Aug. 2023, 日本機械学会 機械力学・計測制御部門, 学術業績賞　　　　　　　　　　　　　　　
梶原逸朗

2018, 日本機械学会 機械力学・計測制御部門, 部門功績賞　　　　　　　　　　　　　　　
梶原 逸朗

2017, 日本機械学会, 120周年記念功労者表彰　　　　　　　　　　　　　　　
梶原 逸朗

2016, 可視化情報学会賞, 技術賞　　　　　　　　　　　　　　　
梶原 逸朗

2015, 日本機械学会, 論文賞　　　　　　　　　　　　　　　
梶原 逸朗

2010, 情報ストレージ研究推進機構, 論文賞　　　　　　　　　　　　　　　
梶原 逸朗

2008, 日本機械学会 機械力学・計測制御部門, パイオニア賞　　　　　　　　　　　　　　　
梶原 逸朗

2005, 日本機械学会 機械力学・計測制御部門, 部門貢献表彰　　　　　　　　　　　　　　　
梶原 逸朗, Japan

1989, 日本機械学会, 論文賞　　　　　　　　　　　　　　　
梶原 逸朗, Japan

1984, 日本機械学会, 畠山賞　　　　　　　　　　　　　　　
梶原 逸朗, Japan

Geometric and dynamic error compensation of dual-drive machine tool based on mechanism-data hybrid method
Qi Liu, Hong Lu, Heisei Yonezawa, Ansei Yonezawa, Itsuro Kajiwara, Tao Jiang, Jiji He
Mechanical Systems and Signal Processing, 224, 112041, 1, 26, Elsevier BV, 01 Jan. 2025, [Peer-reviewed]
English, Scientific journal

Experimental verification of model-free active damping system based on virtual controlled object and fuzzy sliding mode control
Heisei Yonezawa, Ansei Yonezawa, Itsuro Kajiwara
Mechanical Systems and Signal Processing, 224, 111961, 1, 22, 01 Jan. 2025, [Peer-reviewed], [Last author]
English, Scientific journal, To actively suppress vibrations in mechanical structures, this research presents a novel fuzzy sliding mode controller that can be designed without involving mathematical plant modeling and any plant's parameters. The proposed strategy introduces a virtual controlled object (VCO)-based model-free scheme into a sliding mode control (SMC) system while addressing chattering mitigation by adaptive fuzzy inference. A framework of the model-free design is first formulated by interposing the VCO between a real controlled structure and an actuator. Based on a simple controlled frequency band-based design policy, the VCO, which is represented by a single-degree-of-freedom (SDOF) system, is specified to enable model-free active controller design. The VCO-based design process is then combined with SMC, and a Lyapunov function approach is employed to analyze the convergence. Furthermore, the chattering issue, which hinders successful implementation of SMC, is explicitly addressed by employing a fuzzy inference system. The fuzzy rules adjust the control effort online to ensure rapidly convergence to the sliding surface while avoiding drastic switching of the control input, in accordance with variations of the switching function. Finally, experimental verifications are performed by applying the proposed vibration controller to a cantilever plate with characteristic perturbations. The verification results demonstrate that the proposed fuzzy SMC provides sufficient vibration reduction and realizes high robustness to changes in the controlled object.

Experimental validation of adaptive grey wolf optimizer-based powertrain vibration control with backlash handling
Heisei Yonezawa, Ansei Yonezawa, Itsuro Kajiwara
Mechanism and Machine Theory, 203, 105825, 1, 22, Elsevier BV, Nov. 2024, [Peer-reviewed], [Last author]
English, Scientific journal

One-Shot Data-Driven Design for Feedback Controller and Reference Model With BIBO Stability
Shuichi Yahagi, Itsuro Kajiwara
IEEE Access, 12, 147882, 147893, Institute of Electrical and Electronics Engineers (IEEE), Oct. 2024, [Peer-reviewed], [Last author]
English, Scientific journal

Compensation approach for discretization constraint in automobile powertrain control and its performance evaluation
Yoshifusa ITO, Masaki HIRATA, Heisei YONEZAWA, Shota SATO, Takashi HATANO, Chiaki NISHIDOME, Itsuro KAJIWARA
Transactions of the JSME, 1, 20, Japan Society of Mechanical Engineers, Aug. 2024, [Peer-reviewed], [Last author]
Japanese, Scientific journal

Practical one-shot data-driven design of fractional-order PID controller: Fictitious reference signal approach
Ansei Yonezawa, Heisei Yonezawa, Shuichi Yahagi, Itsuro Kajiwara
ISA Transactions, 152, 208, 216, Elsevier BV, Jul. 2024, [Peer-reviewed], [Last author]
English, Scientific journal

Experimental verification of active oscillation controller for vehicle drivetrain with backlash nonlinearity based on norm-limited SPSA
Heisei Yonezawa, Ansei Yonezawa, Itsuro Kajiwara
Proceedings of the Institution of Mechanical Engineers, Part K: Journal of Multi-body Dynamics, (First published online), 1, 16, SAGE Publications, 01 Apr. 2024, [Peer-reviewed], [Last author]
English, Scientific journal, To address vehicle drivetrain vibrations that cause discomfort and poor drivability, this study proposes a new active damping strategy with simple backlash compensation based on the simultaneous perturbation stochastic approximation (SPSA) with norm-limited update vector. First, an experimental device developed for a simplified drivetrain mechanism is demonstrated. A mechanism for reproducing both the contact mode and the backlash mode is included in the device. For the contact mode, a model-based [Formula: see text] controller is employed as the baseline damping strategy. Further, to mitigate the backlash effect, a simple algorithm based on mode-switching-based compensation is used with the [Formula: see text] controller. In particular, for the critical controller parameters, this article presents a systematic design approach to search for their optimal values. The key parameters, which are needed for the backlash and contact mode controllers, are simultaneously auto-tuned using norm-limited update vector-based SPSA, which ensures the stability in the iterative tuning. The novelty of this study is that both the backlash mode controller and the contact mode controller are simultaneously optimized by the improved version of SPSA, thus realizing a comprehensive auto-tuning design of an active drivetrain damping system. Finally, the active controller is experimentally verified using the actual test device. Comparative studies show that the proposed approach significantly reduces drivetrain vibrations and is robust against fluctuations in the backlash.

Final state control-based active compensation for backlash in vibration suppression of automobile powertrain
Masaki Hirata, Heisei Yonezawa, Ansei Yonezawa, Itsuro Kajiwara
International Journal of Control, (First published online), 1, 13, Informa UK Limited, 01 Apr. 2024, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal

Simple Inverse Kinematics Computation Considering Joint Motion Efficiency
Ansei Yonezawa, Heisei Yonezawa, Itsuro Kajiwara
IEEE Transactions on Cybernetics, 54, 9, 4903, 4914, Institute of Electrical and Electronics Engineers (IEEE), 28 Mar. 2024, [Peer-reviewed], [Last author]
English, Scientific journal

Grey wolf optimization tuned drivetrain vibration controller with backlash compensation strategy using time-dependent-switched Kalman filter
Heisei Yonezawa, Ansei Yonezawa, Itsuro Kajiwara
Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, (First published online), 1, 14, SAGE Publications, 24 Mar. 2024, [Peer-reviewed], [Last author]
English, Scientific journal, To improve the performance and durability of vehicle components, efforts have been made to reduce driveline oscillations using advanced active control algorithms. However, existing methods often rely on subjective parameter adjustments, which can be burdensome for designers. This study introduces an effective tuning algorithm for a driveline vibration controller that accounts for nonlinear backlash effects. Initially, a driveline dynamics model is developed to focus on transient oscillations resulting from changes in driving force and the presence of nonlinear backlash. The backlash impact is incorporated into the model through a discontinuous dead-zone region. Two operational dynamics, which are the contact mode and the backlash mode, are considered. A dynamic output feedback [Formula: see text] controller is designed as a baseline controller to mitigate low-frequency resonance in the driveline. A solution for managing the nonlinear backlash challenges is introduced, involving the use of a simple control mode switching algorithm in conjunction with the controller. This algorithm relies on a time-dependent-switched Kalman filter. Additionally, the optimal settings for the parameters needed by the mode-switching algorithm are autonomously determined using the grey wolf optimizer (GWO). The proposed active controller can be implemented in real vehicles by using an on-vehicle acceleration sensor and electronic control unit (ECU). In a simulation environment, the vehicle body vibration is online fed back to the resultant controller, and an actuator is supposed to apply control commands to the driveline. The effectiveness of this newly proposed active controller is confirmed through comparative tests, revealing the superior vibration control.

Active vibration control for thin curved structures using dielectric elastomer actuators
Toshiki Hiruta, Hiroki Ishihara, Naoki Hosoya, Shingo Maeda, Kentaro Takagi, Itsuro Kajiwara
Smart Materials and Structures, IOP Publishing, 12 Feb. 2024, [Peer-reviewed], [Last author]
English, Scientific journal, Abstract

This study proposes an active vibration control technique for pipe structures using dielectric elastomer actuators (DEAs). Vibrations in pipe structures must be eliminated to improve their mechanical reliability, and active vibration control techniques can be applied for effective vibration suppression. Soft actuators, which can completely fit pipe structures with complex-shaped surfaces, are required to transfer their vibration reduction forces to the target. DEA is suitable for this kind of target structure because DEA is characterized by high stretchability, flexibility, large deformation, and fast response. By applying the DEA, the effectiveness of vibration control for the pipe structure was experimentally demonstrated. A stacked DEA was fabricated and attached to the target structure. Its shape and placement were determined based on a modal analysis of the target structure. A control system, in which the controller for the active vibration control was designed based on H_∞ control theory, was composed. The vibration control experiment was conducted using the controller with a digital control system, and the vibration reduction effect was evaluated based on the frequency response of the target pipe structure.

Data-driven design of model-free control for reference model tracking based on an ultra-local model: Application to vehicle yaw rate control
Shuichi Yahagi, Itsuro Kajiwara
Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 1, 13, SAGE Publications, 09 Jan. 2024, [Last author]
English, Scientific journal, Lateral vehicle dynamics control is important for autonomous driving. This paper presents a data-driven design of model-referenced model-free control (DD-MR-MFC) based on an ultra-local model for vehicle yaw rate control. The characteristics of lateral vehicle dynamics systems depend on vehicle velocities and weights. For this system, fixed proportional–integral–derivative (PID) controllers cannot provide the desired control performance. Additionally, although model-based control can be applied to lateral vehicle dynamics, the modeling process is time-consuming. To efficiently design controllers that can realize the desired performance, we adopt a model-free approach. In this study, the control law of practical MR-MFC is derived by extending the traditional MFC based on an ultra-local model and using a data-driven design method. The MFC approach can be applied to nonlinear systems with few parameters, and the data-driven method provides optimized parameters from single-experiment time-series data without the need for repeated experiments and system model to be controlled. Additionally, the processing cost is considerably low because the controller parameter can be obtained using least-square methods. The effectiveness of the proposed method is verified using a multibody vehicle simulator. The yaw rate tracking performance is examined under different velocities and loads. Results showed that the root-mean-square error of the proposed method is approximately 1/100th of that when using a fixed PID controller optimized using a data-driven method.

Novel powertrain vibration controller with six rules-based fuzzy inference for time-fluctuated control period
Heisei Yonezawa, Ansei Yonezawa, Itsuro Kajiwara
IEEE Access, 12, 11972, 11986, Institute of Electrical and Electronics Engineers (IEEE), Jan. 2024, [Peer-reviewed], [Last author]
English, Scientific journal

Improved Six Rules-Based Fuzzy Compensation for Time-Varying Control Cycle in Active Powertrain Oscillation Reduction
Heisei Yonezawa, Ansei Yonezawa, Itsuro Kajiwara
ASME 2023 International Mechanical Engineering Congress and Exposition, 6, Paper No: IMECE2023-113274, American Society of Mechanical Engineers, 29 Oct. 2023, [Peer-reviewed], [Last author]
English, International conference proceedings, Abstract

To prevent the degradations of comfort and drivability, this research presents an improved fuzzy-logic-based active oscillation control algorithm for an automotive powertrain with a time-fluctuated control cycle limitation. A sampled-data controller is firstly employed as the base control, and a model-predictive algorithm is implemented to compute the optimal control signals at a periodic time interval. However, the update timing of the real control input fluctuates over time due to the powertrain actuator limitation. The fuzzy reasoning is applied to tackle the time-fluctuated control cycles. In the present method, the update timing is translated into some fuzzy sets. Moreover, the periodic control signals by the sampled-data controller are combined as fuzziness, resulting in linguistic fuzzy sets. Six fuzzy rules are created based on those fuzzy sets to derive feasible control inputs at the fluctuated updating timings. The control strategy is tested via simulations with a powertrain oscillation model. The compensation effect is observed for the two patterns of the fluctuated control cycles. In addition, the test results confirm the improvement of the oscillation reduction over a conventional control algorithm.

Experimental Comparison of Model-Free Vibration Control Based on Virtual Controlled Object and Model-Based Control: Robustness to Characteristic Changes in Actual Controlled Object
Ansei Yonezawa, Heisei Yonezawa, Itsuro Kajiwara
ASME 2023 International Mechanical Engineering Congress and Exposition, 6, Paper No: IMECE2023-112871, American Society of Mechanical Engineers, 29 Oct. 2023, [Peer-reviewed], [Last author]
English, International conference proceedings, Abstract

Model-free active vibration control based on a virtual controlled object (VCO) has attracted a great deal of attention due to its simplicity. This study experimentally compares VCO-based model-free vibration control with model-based control in terms of the robustness to characteristic changes in an actual controlled object. The VCO is designed so as to achieve model-free vibration suppression in the designated frequency band. A state equation for designing a model-free vibration controller is constructed using only the actuator model and the VCO. The VCO-based model-free controller is designed based on the mixed H2/H∞ synthesis for the state equation. The model-based mixed H2/H∞ controller is designed based on the mathematical model of a both ends supported plate (BESP). The VCO-based and model-based controllers are tuned through vibration control experiment so that both controllers provide the same vibration reduction effects for the BESP. Then these controllers are applied to a vibration control experiment for a cantilever plate which is totally different from the BESP. As a result, the VCO-controller exhibits a good vibration suppression for the cantilever while the model-based one totally fails, revealing the advantage of the VCO-approach over the model-based strategy in the viewpoint of the robustness.

Data-Driven Design for Model-Referenced Model-Free Controller
Shuichi Yahagi, Itsuro Kajiwara
2023 23rd International Conference on Control, Automation and Systems (ICCAS), No. TuB2-2, IEEE, 17 Oct. 2023, [Peer-reviewed], [Last author]
English, International conference proceedings

Efficient parameter tuning to enhance practicability of a model-free vibration controller based on a virtual controlled object
Ansei Yonezawa, Heisei Yonezawa, Itsuro Kajiwara
Mechanical Systems and Signal Processing, 200, 110526, 110526, 110526, Elsevier BV, Oct. 2023, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal

Efficient Tuning Scheme of Mode-Switching-Based Powertrain Oscillation Controller Considering Nonlinear Backlash
Heisei Yonezawa, Ansei Yonezawa, Itsuro Kajiwara
IEEE Access, 11, 93935, 93947, Institute of Electrical and Electronics Engineers (IEEE), Sep. 2023, [Peer-reviewed], [Last author]
English, Scientific journal

Experimental verification of active damping of powertrain vibrations with simple fuzzy logic compensation for time-varying control period
Heisei Yonezawa, Ansei Yonezawa, Takashi Hatano, Shigeki Hiramatsu, Chiaki Nishidome, Itsuro Kajiwara
Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 095440702311781, 1, 10, SAGE Publications, 02 Jun. 2023, [Peer-reviewed], [Last author]
English, Scientific journal, To ensure comfortability and lifetime of components, transient vibrations in a vehicle powertrain must be suppressed. This study proposes a novel active vibration control strategy with straightforward fuzzy inference compensation for time-fluctuations of control periods of engines used as actuators. First, a model prediction algorithm including a sampled-data controller (SDC) is applied for addressing the maximal phase lag of the control input caused by the fluctuated control period. Fluctuated renewal timings of the control input that are deviated from those of the periodical operated SDC are defined by fuzzy sets. These fuzzy sets are expressed as “Nearly past timing” and “Nearly future timing.” Using a human-intuition-like fuzzy compensation with only four inference rules, unknown control inputs at fluctuated update timings are reasonably determined from such fuzzy sets and periodical control signals given by the SDC. Experiments using an actual test device are performed to investigate the damping performance of the proposed control scheme. The experimental tests demonstrate that the novel active damping strategy significantly reduces transient vibrations despite the fluctuated control period. Moreover, several different test conditions newly reveal the robustness of the fuzzy compensation against fluctuations of variable regions in the control periods.

Noniterative data-driven gain-scheduled controller design based on fictitious reference signal
Shuichi Yahagi, Itsuro Kajiwara
IEEE Access, 1, 12, Institute of Electrical and Electronics Engineers (IEEE), Jun. 2023, [Peer-reviewed], [Last author]
English, Scientific journal

Grey-Wolf-Optimization-Algorithm-Based Tuned P-PI Cascade Controller for Dual-Ball-Screw Feed Drive Systems
Qi Liu, Hong Lu, Heisei Yonezawa, Ansei Yonezawa, Itsuro Kajiwara, Ben Wang
Mathematics, 11, 10, 2259, 2259, MDPI AG, 11 May 2023, [Peer-reviewed]
English, Scientific journal, Dual-ball-screw feed drive systems (DBSFDSs) are designed for most high-end manufacturing equipment. However, the mismatch between the dynamic characteristic parameters (e.g., stiffness and inertia) and the P-PI cascade control method reduces the accuracy of the DBSFDSs owing to the structural characteristic changes in the motion. Moreover, the parameters of the P-PI cascade controller of the DBSFDSs are always the same even though the two axes have different dynamic characteristics, and it is difficult to tune two-axis parameters simultaneously. A new application of the combination of the grey wolf optimization (GWO) algorithm and the P-PI cascade controller is presented to solve these problems and enhance the motion performance of DBSFDSs. The novelty is that the flexible coupling model and dynamic stiffness obtained from the motor current can better represent the two-axis coupling dynamic characteristics, and the GWO algorithm is used to adjust the P-PI controller parameters to address variations in the positions of the moving parts and reflect characteristic differences between the two axes. Comparison of simulation and experimental results validated the superiority of the proposed controller over existing ones in practical applications, showing a decrease in the tracking error of the tool center and non-synchronization error of over 34% and 39%, respectively.

A method of testing pear fruit firmness with dielectric elastomer actuator excitation
Toshiki Hiruta, Kaishi Sasaki, Naoki Hosoya, Shingo Maeda, Kentaro Takagi, Itsuro Kajiwara
Electroactive Polymer Actuators and Devices (EAPAD) XXV, 12482, 41, 48, SPIE, 28 Apr. 2023, [Peer-reviewed], [Last author]
English, International conference proceedings

Experimental study of model-free vibration control based on a virtual controlled object considering parameter uncertainty of actuator
Ansei Yonezawa, Heisei Yonezawa, Itsuro Kajiwara
Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, (published online), SAGE Publications, 21 Dec. 2022, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal, This study experimentally verifies robustness of a model-free vibration controller based on a virtual controlled object (VCO) considering parametric uncertainty of actuator. A proof-mass actuator, which can be modeled as a single-degree-of-freedom (SDOF) system, is used. A VCO, which is defined as an SDOF structure, is introduced between a real controlled object and the actuator model. The parameters of the VCO are determined so as to achieve model-free vibration control. A state equation to derive the model-free controller is constructed using the two-degree-of-freedom (2DOF) structure composed of the actuator model and the VCO. The parametric uncertainty of the actuator is quantitatively characterized in the 2DOF structure. The mixed [Formula: see text] control theory is used to design a model-free controller. The vibration suppression performance and robustness to the actuator uncertainty of the proposed method are validated by experiments. Simulation studies are also conducted to enhance the validity of the experimental results. As a result, the proposed damping method exhibits good damping performance and strong robustness to the actuator uncertainty and characteristic changes in controlled object.

Active Reduction of Transient Driveline Oscillations with Fuzzy Update Timings of Control Input
Heisei Yonezawa, Ansei Yonezawa, Takashi Hatano, Shigeki Hiramatsu, Chiaki Nishidome, Itsuro Kajiwara
2022 10th International Conference on Control, Mechatronics and Automation (ICCMA), 108, 115, IEEE, 09 Nov. 2022, [Peer-reviewed], [Last author]
English, International conference proceedings

Noise Tolerance of Online Self-Tuning Mechanism for Model-Free Vibration Controller Based on a Virtual Controlled Object
Ansei Yonezawa, Heisei Yonezawa, Itsuro Kajiwara
2022 10th International Conference on Control, Mechatronics and Automation (ICCMA), 88, 93, IEEE, 09 Nov. 2022, [Peer-reviewed], [Last author]
English, International conference proceedings

Two-Degree-of-Freedom Controller Design Based on a Data-Driven Estimation Approach
Tatsunari Sakai, Shuichi Yahagi, Itsuro Kajiwara
IEEE Access, 10, 120475, 120491, Institute of Electrical and Electronics Engineers (IEEE), Nov. 2022, [Peer-reviewed], [Last author]
English, Scientific journal

Fuzzy-reasoning-based robust vibration controller for drivetrain mechanism with various control input updating timings
Heisei Yonezawa, Ansei Yonezawa, Takashi Hatano, Shigeki Hiramatsu, Chiaki Nishidome, Itsuro Kajiwara
Mechanism and Machine Theory, 175, 104957, 104957, Elsevier BV, Sep. 2022, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal

Non-Iterative Data-Driven Tuning of Model-Free Control Based on an Ultra-Local Model
Shuichi Yahagi, Itsuro Kajiwara
IEEE Access, 10, 72773, 72784, Institute of Electrical and Electronics Engineers (IEEE), Jul. 2022, [Peer-reviewed], [Last author]
English, Scientific journal

Direct data-driven tuning of look-up tables for feedback control systems
Shuichi Yahagi, Itsuro Kajiwara
IEEE Control Systems Letters, 1, 6, Institute of Electrical and Electronics Engineers (IEEE), Jun. 2022, [Peer-reviewed], [Last author]
English, Scientific journal

Vibration control for various structures with time-varying properties via model-free adaptive controller based on virtual controlled object and SPSA
Ansei Yonezawa, Heisei Yonezawa, Itsuro Kajiwara
Mechanical Systems and Signal Processing, 170, 108801, 108801, Elsevier BV, May 2022, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal

Stability Improvement of Model-Free Control Based on a Virtual Structure Against the Resonance of a Proof-Mass Actuator
Yuto Sato, Heisei Yonezawa, Ansei Yonezawa, Itsuro Kajiwara
Journal of Vibration Engineering & Technologies, (published online), 1, 14, Springer Science and Business Media LLC, 08 Feb. 2022, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal,

This study improves the robustness of the model-free controller based on a virtual structure. Additionally, the adverse interference between the proof-mass actuator resonance and a controlled object is investigated as it is not clarified in the previous studies.




A virtual structure modeled as a SDOF system was inserted between the actuator and the actual controlled object. This achieved the indirect damping of the actual controlled object and model-free control. Vibration control simulations were conducted for various finite element models with a model-free $${H}_{\infty }$$

H
∞

controller based on a virtual structure. The results demonstrate that the actuator resonance adversely affects the stability of the control system when the controlled object has a mode whose natural frequency is too close to that of the actuator. Therefore, a notch filter was applied to the model-free $${H}_{\infty }$$

H
∞

controller design approach to suppress the resonance without affecting the damping performance. The improved controller with notch filter is more robust to the resonance of the actuator than the previous one.




The resonance of the proof-mass actuator adversely affects the stability of the control system composed of the previous model-free $${H}_{\infty }$$

H
∞

controller when the low-order vibration mode of the actual controlled object is too close to the natural frequency of the actuator. Introducing a notch filter into the model-free approach based on a virtual structure effectively reduces the negative impact due to the resonance of the actuator and improves the robustness of the control system.

Parameter tuning technique for a model-free vibration control system based on a virtual controlled object
Ansei Yonezawa, Heisei Yonezawa, Itsuro Kajiwara
Mechanical Systems and Signal Processing, 165, 108313, 1, 18, Elsevier BV, Feb. 2022, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal, A parameter tuning technique without manual trial-and-error procedures is proposed for a controller in a model-free vibration control system based on a virtual controlled object (VCO), which is defined as a single-degree-of-freedom (SDOF) system. The model-free control system is constructed by inserting a VCO between the actuator and the actual controlled object. A reference controlled object (RCO), which is also expressed as an SDOF system, is defined for the configured model-free control system. Then the loss function, which is calculated using the RCO vibration control simulation results, is used to evaluate the vibration suppression performance. The simultaneous perturbation stochastic approximation (SPSA) adjusts the controller tuning parameters to minimize the loss function. The SPSA- and RCO-based tuning procedures automatically tune the model-free controller without manual trial-and-error procedures. Simulations and experiments demonstrate that a model-free linear quadratic regulator designed by the proposed approach provides sufficient vibration reduction.

Measurements of S0 mode Lamb waves using a high-speed polarization camera to detect damage in transparent materials during non-contact excitation based on a laser-induced plasma shock wave
Naoki Hosoya, Tsubasa Katsumata, Itsuro Kajiwara, Takashi Onuma, Atsushi Kanda
Optics and Lasers in Engineering, 148, 106770, 1, 10, Elsevier BV, Jan. 2022, [Peer-reviewed]
English, Scientific journal

Firmness evaluation of postharvest pear fruit during storage based on a vibration experiment technique using a dielectric elastomer actuator
Toshiki Hiruta, Kaishi Sasaki, Naoki Hosoya, Shingo Maeda, Itsuro Kajiwara
Postharvest Biology and Technology, 182, 111697, 1, 8, Elsevier BV, Dec. 2021, [Peer-reviewed], [Last author]
English, Scientific journal

Vibration Control System Construction Method without Controlled Object Modeling　　　　　　　　　　　　　　　
Ansei Yonezawa, Heisei Yonezawa, Itsuro Kajiwara
Proceedings of the 9th International Conference on Control, Mechatronics and Automation (ICCMA2021), M1-0038, Nov. 2021, [Peer-reviewed], [Last author]
English, International conference proceedings

Experimental Verification of Model-Free Vibration Control Technique Based on a Virtual Controlled Object Considering Actuator Parameter Uncertainty
Ansei Yonezawa, Heisei Yonezawa, Itsuro Kajiwara
Proceedings of International Mechanical Engineering Congress & Exposition (IMECE2021), 095440622211408, Paper: 69100, (published online), SAGE Publications, Nov. 2021, [Peer-reviewed], [Last author]
English, International conference proceedings, This study experimentally verifies robustness of a model-free vibration controller based on a virtual controlled object (VCO) considering parametric uncertainty of actuator. A proof-mass actuator, which can be modeled as a single-degree-of-freedom (SDOF) system, is used. A VCO, which is defined as an SDOF structure, is introduced between a real controlled object and the actuator model. The parameters of the VCO are determined so as to achieve model-free vibration control. A state equation to derive the model-free controller is constructed using the two-degree-of-freedom (2DOF) structure composed of the actuator model and the VCO. The parametric uncertainty of the actuator is quantitatively characterized in the 2DOF structure. The mixed [Formula: see text] control theory is used to design a model-free controller. The vibration suppression performance and robustness to the actuator uncertainty of the proposed method are validated by experiments. Simulation studies are also conducted to enhance the validity of the experimental results. As a result, the proposed damping method exhibits good damping performance and strong robustness to the actuator uncertainty and characteristic changes in controlled object.

Vibration control of membrane structures using multiple dielectric elastomer actuators　　　　　　　　　　　　　　　
Thosiki Hiruta, Hiroki Ishihara, Naoki Hosoya, Shingo Maeda, Itsuro Kajiwara
Proceedings of the 21st International Conference on Control, Automation and Systems, FB5-1, 1932, 1936, Oct. 2021, [Peer-reviewed], [Last author]
English, International conference proceedings

Direct tuning of PID controller and reference model with input constraint
Shuichi Yahagi, Itsuro Kajiwara
Proceedings of the 21st International Conference on Control, Automation and Systems, TC3-2, 1424, 1429, IEEE, Oct. 2021, [Peer-reviewed], [Last author]
English, International conference proceedings, The direct tuning of controller parameters based on data-driven control has attracted considerable attention because of its simple controller design. In this study, we proposed a direct tuning method based on a fictitious reference signal to obtain controller and reference model parameters. In the method, predicted input/output data with respect to controller parameters are used. The predicted data with pole information are obtained based on instability detecting-fictitious reference iterative tuning, which can ensure bounded-input, bounded-output stability. We derived a new objective function with constraints using the predicted data to automatically obtain controller and reference model parameters to perform a fast response under model matching and input constraints. The function consists of an evaluation part in which the fastest responsive reference model is requested and constraint parts that include model-matching errors and input amounts. A simulation was performed to verify the effectiveness of the proposed method. The results showed that the proposed method provided controller and reference model parameters for the model matching and input constraints from one-shot data without trial and error.

Direct tuning method of gain‐scheduled controllers with the sparse polynomials function
Shuichi Yahagi, Itsuro Kajiwara
Asian Journal of Control, (published online), 1, 16, Wiley, 18 Aug. 2021, [Peer-reviewed], [Last author]
English, Scientific journal

Direct tuning of gain-scheduled controller for electro-pneumatic clutch position control
Shuichi Yahagi, Itsuro Kajiwara
Advances in Mechanical Engineering, 13, 8, 1, 12, SAGE Publications, Aug. 2021, [Peer-reviewed], [Last author]
English, Scientific journal, This study proposes a gain-scheduled controller with direct tuning for the position control of a pneumatic clutch actuator that is installed in heavy-duty trucks. Pneumatic clutch actuators are highly nonlinear systems and cannot be easily controlled. Industries require a simple controller design that is easy to understand and requires few trial-and-error calibrations. Therefore, we adopted a gain-scheduled proportional integral derivative (PID) control law, which is a well-known and easy-to-understand nonlinear control method. In this approach, a gain scheduler is expressed using polynomials composed of coefficient parameters and controlled object states. The unknown coefficient parameters of the polynomials are directly tuned from the controlled object input/output data without having to use a controlled object model. The proposed controller design procedure is simple and does not require system identification or trial-and-error tuning. The effectiveness of the proposed method is verified by an experiment using an actual vehicle. The experimental results confirm the effectiveness of the proposed method for the position control of pneumatic clutch actuators.

Experimental evaluation of frequency response and firmness of apples based on an excitation technique using a dielectric elastomer actuator
Toshiki Hiruta, Naoki Hosoya, Shingo Maeda, Itsuro Kajiwara
Sensors and Actuators A: Physical, 330, 112830, 1, 8, Elsevier BV, May 2021, [Peer-reviewed], [Corresponding author]
English, Scientific journal

Direct tuning of the data-driven controller considering closed-loop stability based on a fictitious reference signal
Shuichi Yahagi, Itsuro Kajiwara
Measurement and Control, 54, 5-6, 1026, 1042, SAGE Publications, 29 Apr. 2021, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal, The direct tuning of controller parameters, which is based on data-driven control, has been attracting considerable attention because of the ease of its control system design. In practical use, it is important to consider the stability of the closed-loop system and model matching with few design parameters. In this study, we propose a direct tuning method based on a fictitious reference signal that considers the bounded-input bounded-output (BIBO) and model matching without repeating experiments. The proposed method includes two steps. In the first step, the BIBO stability is satisfied. The pole information is lost in the cost function of the conventional method using a fictitious reference signal. Then, we derive a new cost function that can prevent the loss of the pole information. This provides controller parameters that can stabilize the closed-loop system. The model matching between the reference model and the closed-loop system is considered in the second step. When model matching is achieved, the characteristics of the reference model almost match those of the closed-loop system, including the gain and phase margins. The parameters of the reference model are automatically tuned to realize model matching. Using the two-step method, we can obtain parameters considering BIBO stability and the model matching. In addition, there are no design parameters apart from the dealing noise. Two simulations and an experiment were performed on a system with dead time to verify the effectiveness of the proposed two-step method. The results showed that the proposed method provides BIBO stability and model-matched control parameters from the measured data through a one-time experiment without trial and error.

Soft Mango Firmness Assessment Based on Rayleigh Waves Generated by a Laser-Induced Plasma Shock Wave Technique
Nayuta Arai, Masafumi Miyake, Kengo Yamamoto, Itsuro Kajiwara, Naoki Hosoya
Foods, 10, 323, 1, 16, MDPI AG, 03 Feb. 2021, [Peer-reviewed]
English, Scientific journal, Many methods based on acoustic vibration characteristics have been studied to indirectly assess fruit ripeness via fruit firmness. Among these, the frequency of the 0S2 vibration mode measured on the equator has been examined, but soft-flesh fruit do not show the 0S2 vibration mode. In this study, a Rayleigh wave is generated on a soft mango fruit using the impulse excitation force generated by a laser-induced plasma shock wave technique. Then, the flesh firmness of mangoes is assessed in a non-contact and non-destructive manner by observing the Rayleigh wave propagation velocity because it is correlated with the firmness (shear elasticity), density, and Poisson’s ratio of an object. If the changes in the density and Poisson’s ratio are small enough to be ignored during storage, then the Rayleigh wave propagation velocity is strongly correlated to fruit firmness. Here, we measure the Rayleigh wave propagation velocity and investigate the effect of storage time. Specifically, we investigate the changes in firmness caused by ripening. The Rayleigh wave propagation velocity on the equator of Kent mangoes tended to decrease by over 4% in 96 h. The Rayleigh wave measured on two different lines propagated independent distance and showed a different change rate of propagation velocity during 96-h storage. Furthermore, we consider the reliability of our method by investigating the interaction of a mango seed on the Rayleigh wave propagation velocity.

Experimental validation of vibration control in membrane structures using dielectric elastomer actuators in a vacuum environment
Toshiki Hiruta, Naoki Hosoya, Shingo Maeda, Itsuro Kajiwara
International Journal of Mechanical Sciences, 191, 106049, 1, 10, Elsevier BV, Feb. 2021, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal

Active vibration control of automobile drivetrain with backlash considering time-varying long control period
Heisei Yonezawa, Itsuro Kajiwara, Chiaki Nishidome, Takashi Hatano, Masato Sakata, Shigeki Hiramatsu
Journal of Automobile Engineering, 235, 2-3, 773, 783, SAGE Publications, Feb. 2021, [Peer-reviewed], [Corresponding author]
English, Scientific journal, Active vibration control of automotive drivetrains must be developed to compensate for the backlash of gears because it causes undesired responses. In addition, an engine used as an actuator has a constraint which makes the control periods longer and time-varying, resulting in deterioration of the control performance. The contribution of this study is to cope with all the issues described above, backlash and the control period constraint, simultaneously. First, a basic experimental device, which simplifies an actual vehicle to focus on the effect due to backlash, is demonstrated. In the device, the control period constraint, which is equivalent to that of an engine, is reproduced by a digital signal processor. To reduce an adverse effect due to the extension of the control period, the sampled-data controller, which does not require discretization in its implementation, is employed. In this paper, predictive processing using the servo-type sampled-data controller is proposed to compensate for the phase delay of the control input caused by the time-varying control period. In addition, a control mode switching technique included in the prediction suppresses undesired responses due to backlash. Finally, control experiments verify the effectiveness of the control system.

Motion and Vibration Control of Automotive Drivetrain with Control Cycle Limitation
H. Yonezawa, I. Kajiwara, C. Nishidome, T. Hatano, M. Sakata, S. Hiramatsu
Vibration Engineering for a Sustainable Future, 1, 87, 93, Springer International Publishing, 2021, [Peer-reviewed]
English, International conference proceedings

Loosening Detection of a Bolted Joint Based on Monitoring Dynamic Characteristics in the Ultrasonic Frequency Region
Takanori Niikura, Naoki Hosoya, Shinji Hashimura, Itsuro Kajiwara, Francesco Giorgio-Serchi
Vibration Engineering for a Sustainable Future, 2, 191, 196, Springer International Publishing, 2021, [Peer-reviewed]
English, International conference proceedings

Application of Physical Function Model to State Estimations of Nonlinear Mechanical Systems
Heisei Yonezawa, Itsuro Kajiwara, Shota Sato, Chiaki Nishidome, Takashi Hatano, Shigeki Hiramatsu
IEEE Access, 9, 12002, 12018, Institute of Electrical and Electronics Engineers (IEEE), Jan. 2021, [Peer-reviewed], [Corresponding author]
English, Scientific journal

Novel Sliding Mode Vibration Controller with Simple Model-free Design and Compensation for Actuator’s Uncertainty
Ansei Yonezawa, Itsuro Kajiwara, Heisei Yonezawa
IEEE Access, 9, 4351, 4363, Institute of Electrical and Electronics Engineers (IEEE), Jan. 2021, [Peer-reviewed], [Corresponding author]
English, Scientific journal

Axial force measurement of the bolt/nut assemblies based on the bending mode shape frequency of the protruding thread part using ultrasonic modal analysis
Naoki Hosoya, Takanori Niikura, Shinji Hashimura, Itsuro Kajiwara, Francesco Giorgio-Serchi
Measurement: Journal of the International Measurement Confederation, 162, 107914, 1, 10, 01 Oct. 2020, [Peer-reviewed]
English, Scientific journal, © 2020 The Author(s) Bolt/nut assemblies are commonly used in machines and structures to enable easy assembly and disassembly. However, the axial force (i.e. the fastening force) of such assemblies decreases due to recursive external loading on the bolt/nut assemblies or chronic progressive wearing of the assemblies. Consequently, axial force monitoring is essential in preventing serious failure due to loss of functions in the assembly or fatigue. This study proves that the axial force on bolt/nut assemblies can be measured by investigating changes in the bending mode natural frequency of the bolt's threaded portion that protrudes from the nut (hereinafter referred to as the “protruding thread part“). This method is postulated on the observation that a reduction in the axial force decreases the joint stiffness of the bolt/nut assembly at the protruding thread part, leading to a shift in the characteristic peak frequency of the bending mode. A bolt/nut assembly is formed and its bending mode shapes and bending mode frequencies are obtained by impact tests. A series of tests are performed to define a quantitative measure of the correlation between the shift in the bending mode frequency and the axial force on the bolt/nut assembly. This method enables to perform measurement of the axial force on the bolt/nut assembly of −40 to −50% in the frequency range between 25 and 35 kHz. Dependency of the accuracy of this method on bolt aspect ratio (protruding length/nominal diameter) shows that lower aspect ratios are better suited for measuring axial force via bending mode frequency variation., 13302765

Model-free vibration control based on a virtual controlled object considering actuator uncertainty
Ansei Yonezawa, Itsuro Kajiwara, Heisei Yonezawa
Journal of Vibration and Control, 27, 11-12, 1324, 1335, SAGE Publications, 02 Jul. 2020, [Peer-reviewed], [Corresponding author]
English, Scientific journal, The purpose of this research is to construct a simple and practical controller design method, considering the actuator’s parameter uncertainty, without using a model of controlled objects. In this method, a controller is designed with an actuator model including a single-degree-of-freedom virtual structure inserted between actuator and controlled object, resulting in a model-free controller design. Furthermore, an [Formula: see text] control problem is defined so that the actuator’s parameter uncertainty is compensated by satisfying a robust stability condition. Because the actuator model including the virtual controlled object is a simple low-order system, and the actuator’s parameter uncertainty is considered, a controller with high robustness to the actuator’s parameter uncertainty can be designed based on traditional model-based control theory. The effectiveness of the proposed method is verified by both simulation and experiment.

Slip control during inertia phase of clutch-to-clutch shift using model-free self-tuning proportional-integral-derivative control　　　　　　　　　　　　　　　
Yahagi, S., Kajiwara, I., Shimozawa, T.
Journal of Automobile Engineering, 234, 9, 2279, 2290, Apr. 2020, [Peer-reviewed]
English, Scientific journal

Experimental verification of model-free active vibration control approach using virtually controlled object　　　　　　　　　　　　　　　
Yonezawa, H., Kajiwara, I., Yonezawa, A.
Journal of Vibration and Control, 26, 19-20, 1656, 1667, Jan. 2020, [Peer-reviewed], [Corresponding author]
English, Scientific journal

Frequency response function measurements of rotational degrees of freedom using a non-contact moment excitation based on nanosecond laser ablation　　　　　　　　　　　　　　　
Hosoya, N, Ozawa, S, Kajiwara, I
Journal of Sound and Vibration, 456, 239, 253, Sep. 2019, [Peer-reviewed]
English, Scientific journal

Vibration Control of automotive drive system with nonlinear gear backlash　　　　　　　　　　　　　　　
Yonezawa, H, Kajiwara, I, Sato, S, Nishidome, C, Sakata, M, Hatano, T, Hiramatsu, S
Journal of Dynamic Systems, Measurement and Control, 141, 12, No. 121002, Aug. 2019, [Peer-reviewed]
English, Scientific journal

Spherical projectile impact using compressed air for frequency response function measurements in vibration tests　　　　　　　　　　　　　　　
Hosoya, N, Kato, J, Kajiwara, I.
Mechanical Systems and Signal Processing, 134, 106295, 1, 12, Aug. 2019, [Peer-reviewed]
English, Scientific journal

Design of dielectric elastomer actuators for vibration control at high frequencies　　　　　　　　　　　　　　　
Kajiwara, I, Kitabatake, S, Hosoya, N, Maeda, S
International Journal of Mechanical Sciences, 157-158, 849, 857, Jul. 2019, [Peer-reviewed]
English, Scientific journal

Model-free vibration control to enable vibration suppression of arbitrary structures　　　　　　　　　　　　　　　
Yonezawa, H, Kajiwara, I, Yonezawa, A
Proceedings of The 12th Asian Control Conference, Paper: MoB3.1., Jun. 2019, [Peer-reviewed]
English, International conference proceedings

Vibration control of automotive drive system with backlash considering control period constraint
Yonezawa, H, Kajiwara, I, Nishidome, C, Hiramatsu, S, Sakata, M, Hatano, T
Journal of Advanced Mechanical Design, Systems, and Manufacturing, 13, 1, 18-00430, JAPAN SOC MECHANICAL ENGINEERS, 2019, [Peer-reviewed]
English, Scientific journal, This paper proposes a vibration control method of an automotive drive system with backlash to maintain stability and control performance under the control period constraint due to an engine's characteristics. Reducing the vibrations of the automotive drive system remains a challenge when improving the riding comfort and driving performance of automobiles. In particular, a vibration control method must be developed to compensate for the backlash of differential gears because this element degrades the vibration control performance. Furthermore, engines used as actuators have a constraint in which control cycles are made longer due to restrictions of the input update. The roughly updated cycles adversely affect not only the high vibration control performance but also the stability. In this study, we validate the control system for an automotive drive system with backlash by considering the input update limitation. First, a basic experimental device, which abstracts actual vehicles to focus on the influence due to backlash while reflecting only the basic structure of an automotive drive system, is created. Then to cope with the control cycle constraint, sampled-data H-2 control is applied. The servo system is constructed by applying an approximate integrator and frequency shaping. As an approach to compensate for backlash, we propose a simple and practical control mode switching technique. Finally, the effectiveness of the control system is verified experimentally. The results are compared to the control results with those obtained by the traditional discrete approximation.

Evaluation of the clamping force of bolted joints using local mode characteristics of a bolt head　　　　　　　　　　　　　　　
Hosoya, N, Hosokawa, T, Kajiwara, I, Hashimura, S, Huda, F
Journal of Nondestructive Evaluation, 37:75, Dec. 2018, [Peer-reviewed]
English, Scientific journal

Visualization of Lamb waves propagating in transparent materials using high-speed camera　　　　　　　　　　　　　　　
Katsumata, T, Hosoya, N, Kanda, A, Kajiwara, I, Onuma, T
Proceedings on The 5th Asia-Pacific Conference on Engineering and Applied Science, APCEAS-0120, Dec. 2018, [Peer-reviewed]
English, International conference proceedings

Damage detection in pipes based on acoustic excitations using laser-induced plasma
Itsuro Kajiwara, Ryosuke Akita, Naoki Hosoya
Mechanical Systems and Signal Processing, 111, 570, 579, Academic Press, 01 Oct. 2018, [Peer-reviewed]
English, Scientific journal, A health-monitoring system is proposed to detect holes drilled in a pipe based on laser plasma acoustic excitations and acoustic measurements. In this system, an acoustic excitation is applied to a pipe via a laser-induced plasma in air generated by a high-power Nd: YAG pulse laser. Laser-induced plasmas can realize non-contact acoustic impulse excitations. A microphone is used to measure the time response of the acoustic pressure. In this study, we focus on the detection of a hole in the pipe. The reflection of the acoustic wave due to a hole drilled in the pipe induces a change in the time response of the acoustic pressure. Applying a continuous wavelet transform to the measured time response data with/without the hole can locate the position of the hole. This study demonstrates the effectiveness of the present damage detection method based on an acoustic excitation using a laser-induced plasma.

Motion and Vibration Control of Automotive Drive System Considering Gear Backlash Nonlinearity　　　　　　　　　　　　　　　
Yonezawa, H, Kajiwara, I, Sato, S, Nishidome, C, Sakata, M, Hatano, T, Hiramatsu, S
Proceedings of 14th International Conference on Motion and Vibration Control, B-06, Aug. 2018, [Peer-reviewed]
English, International conference proceedings

Experimental verification of a real-time tuning method of a model-based controller by perturbations to its poles
Itsuro Kajiwara, Keiichiro Furuya, Shinichi Ishizuka
Mechanical Systems and Signal Processing, 107, 396, 408, Academic Press, 01 Jul. 2018, [Peer-reviewed]
English, Scientific journal, Model-based controllers with adaptive design variables are often used to control an object with time-dependent characteristics. However, the controller's performance is influenced by many factors such as modeling accuracy and fluctuations in the object's characteristics. One method to overcome these negative factors is to tune model-based controllers. Herein we propose an online tuning method to maintain control performance for an object that exhibits time-dependent variations. The proposed method employs the poles of the controller as design variables because the poles significantly impact performance. Specifically, we use the simultaneous perturbation stochastic approximation (SPSA) to optimize a model-based controller with multiple design variables. Moreover, a vibration control experiment of an object with time-dependent characteristics as the temperature is varied demonstrates that the proposed method allows adaptive control and stably maintains the closed-loop characteristics.

Non-contact and non-destructive Lamb wave generation using laser-induced plasma shock wave
Hosoya Naoki, Yoshinaga Atsushi, Kanda Atsushi, Kajiwara Itsuro
International journal of mechanical sciences, 140, 140, 486, 492, Elsevier, May 2018, [Peer-reviewed]
English, Scientific journal

Numerical simulations of magnetic resonance elastography using finite element analysis with a linear heterogeneous viscoelastic model
Sunao Tomita, Hayato Suzuki, Itsuro Kajiwara, Gen Nakamura, Yu Jiang, Mikio Suga, Takayuki Obata, Shigeru Tadano
Journal of Visualization, 21, 1, 133, 145, 01 Feb. 2018, [Peer-reviewed]
English, Scientific journal, © 2017, The Author(s). Abstract: Magnetic resonance elastography (MRE) is a technique to identify the viscoelastic moduli of biological tissues by solving the inverse problem from the displacement field of viscoelastic wave propagation in a tissue measured by MRI. Because finite element analysis (FEA) of MRE evaluates not only the viscoelastic model for a tissue but also the efficiency of the inversion algorithm, we developed FEA for MRE using commercial software called ANSYS, the Zener model for displacement field of a wave inside tissue, and an inversion algorithm called the modified integral method. The profile of the simulated displacement field by FEA agrees well with the experimental data measured by MRE for gel phantoms. Similarly, the value of storage modulus (i.e., stiffness) recovered using the modified integral method with the simulation data is consistent with the value given in FEA. Furthermore, applying the suggested FEA to a human liver demonstrates the effectiveness of the present simulation scheme. Graphical abstract: [Figure not available: see fulltext.].

Lamb wave generation using nanosecond laser ablation to detect damage
Hosoya, N, Umino, R, Kanda, A, Kajiwara, I, Yoshinaga, A
Journal of Vibration and Control, 24, 24, 5842, 5853, SAGE PUBLICATIONS LTD, 2018, [Peer-reviewed]
English, Scientific journal, This paper proposes a non-contact damage detection method based on Lamb waves generated by laser ablation (LA). Previously, Lamb waves generated by contact-type sensors such as acoustic emission or piezoelectric zirconate titanate devices have been studied to detect damage. Lamb wave generation systems with embedded contact-type excitation devices to objective structures to be inspected may quickly realize large-area damage detection on a huge object such as an aircraft. However, replacing contact-type devices with non-contact devices in Lamb wave generation systems, the systems will have sufficient potential to excite under the specific conditions such as submerged target structures in liquid and high-temperature substances. The LA-generated Lamb waves that have amplitudes several hundred times larger than those generated by conventional laser-thermoelastically generated Lamb waves are of advantage from the viewpoint of the signal-to-noise ratio in the measurements. When the laser fluence reaches 10(12)-10(14) W/m(2), which is greater than that for laser-thermoelastic regime, a LA regime is induced. The amplitudes of the LA-generated Lamb waves might be higher than those of the laser-thermoelastically generated Lamb waves; this is within the scope of the assumption. Since the LA process entails a number of nonlinear processes such as melting, vaporization, and sublimation, it is important to confirm that LA could generate a Lamb wave and its mode. In this paper, Lamb waves that contain broadband frequency elements of more than several hundred kHz are generated by non-contact impulse excitation using LA, which is common in vibration tests in the high-frequency range, laser peening, propulsion of micro-aircraft, bolt loosening diagnosis, etc. The present method is evaluated by comparing the measured and calculated propagation phase and group velocities of the Lamb waves. Furthermore, the feasibility of our approach is demonstrated by non-contact damage detection against an aluminum alloy 2024 plate with a crack.

Dynamic characterizations of underwater structures using non-contact vibration tests based on nanosecond laser ablation in water: evaluation of passive vibration suppression with damping materials　　　　　　　　　　　　　　　
Hosoya, N, Kajiwara, I, Umenai, K, Maeda, S
Journal of Vibration and Control, 24, I6, 3714, 3725, 2018, [Peer-reviewed]
English, Scientific journal

Structural Health Monitoring Based on Laser Excitation Vibration Test and Wavelet Transform　　　　　　　　　　　　　　　
Cao, S, Kajiwara, I, Li, X, Hosoya, N
Proceedings of The 11th International Conference on Sensing Technology, 414, 419, Dec. 2017, [Peer-reviewed]
English, International conference proceedings

Bolt Loosening Diagnosis by Measuring Vibration Responses Excited by Laser Induced Plasma　　　　　　　　　　　　　　　
Singh, M.P, Kajiwara, I, Hosoya, N
Proceedings of The 17th Asian Pacific Vibration Conference, #124, Nov. 2017, [Peer-reviewed]
English, International conference proceedings

Excitation system based on laser-induced plasma to generate Lamb wave　　　　　　　　　　　　　　　
Hosoya, N, Yoshinaga, A, Kanda, A, Umino, R, Kajiwara, I.
Proceedings of International Conference on Engineering Vibration 2017, 121, Sep. 2017, [Peer-reviewed]
English, International conference proceedings

Non-destructive firmness assessment of apples using a non-contact laser excitation system based on a laser-induced plasma shock wave
Naoki Hosoya, Michiru Mishima, Itsuro Kajiwara, Shingo Maeda
POSTHARVEST BIOLOGY AND TECHNOLOGY, 128, 11, 17, ELSEVIER SCIENCE BV, Jun. 2017, [Peer-reviewed]
English, Scientific journal, Various indexes have been used to assess the ripeness of fruit, including peel color and firmness because added value is given to fruit when grade selection is determined objectively. In this paper, we realize a non-destructive firmness assessment for apples by means of a non-contact vibration test method. We investigate their natural frequencies and vibration mode shapes because these factors influence the S-0(2) mode, which is related to firmness. A laser-induced plasma shock wave generated with a high-output Nd: YAG pulsed laser is applied to apples as an excitation force. Firmness is assessed with this non-contact and non-destructive method using the apple's vibration response spectra measured with a laser Doppler vibrometer. The effectiveness of this method is experimentally demonstrated through assessments of apples' firmness, identification of the vibration mode shapes, and a follow-up survey on the flesh firmness of apples during storage. (C) 2017 The Authors. Published by Elsevier B. V.

Active vibration suppression of membrane structures and evaluation with a non-contact laser excitation vibration test
Yuelin Zhang, Toshiki Hiruta, Itsuro Kajiwara, Naoki Hosoya
JOURNAL OF VIBRATION AND CONTROL, 23, 10, 1681, 1692, SAGE PUBLICATIONS LTD, Jun. 2017, [Peer-reviewed]
English, Scientific journal, To realize a vibration suppression of flexible structures like a membrane, our research focuses on introducing smart structures technology into the membrane structure. In this study, the membrane structure is composed of a vibration control system using a flexible Polyvinylidene fluoride (PVDF) film as an actuator. A non-contact vibration test system, which uses a high power Nd: YAG pulse laser for producing an ideal impulse excitation and laser Doppler vibrometers for measuring the response on the membrane, is employed to evaluate the vibration characteristics of the smart membrane structure. To confirm the effectiveness of the proposed method, using a flexible PVDF actuator installed on the membrane structure, control experiments with H control for reducing single mode and multiple modes vibration are conducted. In the results of the control experiments for single mode vibration suppression, a corresponding resonance peak is reduced by around 20 dB. In case of multiple modes vibration suppression, the first and second resonance peaks are reduced by 14 dB and 24 dB, respectively. This study demonstrates that the present control method using a flexible piezoelectric element and a non-contact vibration test system effectively suppress and evaluate the vibration responses of smart membrane structures.

Model-free adaptive control scheme for EGR/VNT control of a diesel engine using the simultaneous perturbation stochastic approximation
Shinichi Ishizuka, Itsuro Kajiwara, Junichi Sato, Yoshifumi Hanamura, Satoshi Hanawa
TRANSACTIONS OF THE INSTITUTE OF MEASUREMENT AND CONTROL, 39, 1, 114, 128, SAGE PUBLICATIONS LTD, Jan. 2017, [Peer-reviewed]
English, Scientific journal, To meet the more stringent environmental requirements of automobile exhaust gas emissions, diesel engines have recently received increased attention due to their high heat efficiency. To lower fuel consumption and reduce exhaust gas simultaneously, fuel combustion must be more precisely controlled. For example, the oxygen concentration, which affects emissions, is controlled by exhaust gas recirculation (EGR) and variable nozzle turbo (VNT). However, realizing a controlled design is difficult due to system non-linearity and strong interference between EGR and VNT. Recently, various design methods have employed the so-called model-based control design, but this design approach is difficult to use when the controlled object is complex. Currently, mass production uses gain scheduling of map-based on proportional-integral-derivative (PID) control, in which each gain is tuned at various operational points. However, map calibration has many drawbacks, including time-consuming tuning, difficulty tuning during transient operations and problems adapting to the individual variations in the engine characteristics. This study proposes a construction method for a model-free adaptive PID controller using the simultaneous perturbation stochastic approximation (SPSA) and its performance is confirmed in an engine bench test.

A New Approach for NOx Soft Sensors for the Aftertreatment of Diesel Engines
S. Ishizuka, I. Kajiwara, J. Sato, Y. Hanamura
Journal of Physics: Conference Series, 744, 1, Institute of Physics Publishing, 03 Oct. 2016, [Peer-reviewed]
English, International conference proceedings, To maintain the NOX concentration at an appropriate level, traditionally an air-path control that regulates the intake and exhaust system of diesel engines aims to control the mass air flow and the manifold absolute pressure, which influence the production of NOX. To improve the control accuracy, a more recent approach takes the NOX concentration directly as a controlled output variable, but the sensors monitoring the NOX concentration are slow to respond. Consequently, a direct sensor is inappropriate as a feedback controller. Instead a mechanism called a soft sensor, which computes the NOX concentration from state quantities of diesel engines, is used. Because the prediction accuracy from the sensor model greatly affects the control performance, it is important to improve the model accuracy. However, deviations in the steady state indicate an insufficient model accuracy. This study proposes a method to construct an adaptive NOX soft sensor that corrects the parameters of the sensor model sequentially using the simultaneous perturbation stochastic approximation while comparing the values computed by the software to actual measurements as well as examines the effectiveness of the proposed method experimentally.

Dynamic characterizations of underwater structures using non-contact vibration test based on nanosecond laser ablation in water: investigation of cavitation bubbles by visualizing shockwaves using the Schlieren method
Naoki Hosoya, Itsuro Kajiwara, Koh Umenai
JOURNAL OF VIBRATION AND CONTROL, 22, 17, 3649, 3658, SAGE PUBLICATIONS LTD, Oct. 2016, [Peer-reviewed]
English, Scientific journal, A pulsed-laser ablation method for non-contact experimental vibration analysis of completely submerged underwater structures is proposed. Although impact testing with an impulse hammer is commonly used for vibration analysis due to its simplicity, impact testing has limited use in underwater conditions. An input-detection-free frequency response function measurement in water will greatly contribute to the development of high-precision and high-speed positioning autonomous underwater vehicles, underwater vehicle-manipulators, underwater robots, submarines, etc., which are used in dangerous conditions (e.g., deep oceans, under ice, and nuclear reactor plants). To achieve these high-performance underwater systems, vibrations due to hydrodynamic parameters (such as added mass, buoyant force, drag force, and damping coefficient) should be suppressed, and vibration tests should be conducted on the actual equipment submerged in water. The proposed method yields the frequency response function by applying a pulsed-laser-ablation excitation force to an underwater structure and measuring the output using a laser Doppler vibrometer. Because the direction, strength, and effective duration of the pulsed-laser-ablation force are essentially constant, this force can be estimated by measuring these properties in advance. Hence, the proposed method realizes input-detection-free frequency response function measurements in underwater conditions.

Nano-second Laser-induced Plasma Shock Wave in Air for Non-contact Vibration Tests
N. Hosoya, M. Nagata, I. Kajiwara, R. Umino
EXPERIMENTAL MECHANICS, 56, 7, 1305, 1311, SPRINGER, Sep. 2016, [Peer-reviewed]
English, Scientific journal, Herein a vibration test method is discussed based on a non-contact, non-destructive excitation input using a laser-induced plasma (LIP) shock wave and a non-contact input estimation using Newton's second law of motion. We have previously introduced a non-contact vibration test method using an excitation force generated by laser ablation, but it cannot be used when the target structure is lightweight, fragile, and small-sized because a crater with a diameter of several micrometers is created. The LIP generates a highly reproducible shock wave, which become an excitation force to a target structure. This shock wave depends on the gas density, gas specific heat ratio, laser fluence, and ambient environment. If these parameters are constant, the LIP excitation force can be estimated beforehand, allowing only the output measurement to determine the frequency response measurement of an input-output relationship of the target structure. After calibrating the LIP excitation, the frequency response function of a target structure can be obtained.

Damage Detection in Transparent Materials Using Non-Contact Laser Excitation by Nano-Second Laser Ablation and High-Speed Polarization-imaging Camera
N. Hosoya, R. Umino, I. Kajiwara, S. Maeda, T. Onuma, A. Mihara
EXPERIMENTAL MECHANICS, 56, 2, 339, 343, SPRINGER, Feb. 2016, [Peer-reviewed]
English, Scientific journal, Although transparent materials with birefringent properties (e.g., solar panels and separator films for secondary cells) are common, damage detection during the manufacturing process is crucial to economically realize high-quality materials. Herein a method using a pulsed-laser and a high-speed polarization-imaging camera is proposed to rapidly detect damage, including scratches and dents, in transparent materials. Specifically, as stress waves, which are generated by a non-contact impulse excitation from laser ablation, propagate through a material, the stress concentrations induced around damage are measured as the two-dimensional birefringent phase differences using a high-speed polarization-imaging camera with a microsecond-order temporal resolution. When stress is dominant, the distribution of the measured birefringent phase difference can be considered the relative distribution of stress. Using acrylic plates as a representative transparent material with several hundred micrometers of damage (e.g., a dent or a scratch), we demonstrate that the proposed method detects damage in a very short timeframe of several microseconds.

Multi-objective optimization for vibration suppression of smart laminated composites
Honda, S, Narita, Y, Kajiwara, I
Mechanical Engineering Journal, 3, 1, 14-00561, 00561-14-00561, The Japan Society of Mechanical Engineers, 2016, [Peer-reviewed]
English, Scientific journal, The present paper proposes a multi-objective optimization technique for smart laminated composites to maximize two conflicting objectives. The first objective is the performance of active vibration control of smart composite with piezoelectric (PZT) actuators. The second is the fundamental frequency of smart structures related to the performance of passive vibration control. Both performances of active and passive vibration control are maximized simultaneously. The vibration suppression of smart structures strongly depends on both actuator placements and vibration mode shapes. It is possible to design vibration mode shapes for laminated fibrous composites since their anisotropy for whole thickness is tailorable by arranging fiber orientation angle in each layer. This allows the smart structure with laminated composite to archive higher performance of vibration suppression than those with isotropic materials. However, the optimized structure results in lower natural frequencies than composites with typical fiber orientation angles since an effective input of control force from actuators is realized for the structure with lower stiffness. This reveals that there is a trade-off relation for smart composite structures between the performance of active vibration suppression and natural frequencies. To disclose this relation, the present study applies the effective multi-objective optimization technique, the refined non-dominated genetic algorithm (NSGAII), and obtains Pareto optimal solutions. Calculated results are successfully validated by a comparison with those from the real-time control experiment where a laser excitation technique which is effective to small sized structures is used.

Quality assessment of apples based on modal analysis using laser-induced plasma shock wave
M. Mishima, N. Hosoya, I. Kajiwara, S. Maeda
PROCEEDINGS OF ISMA2016 INTERNATIONAL CONFERENCE ON NOISE AND VIBRATION ENGINEERING AND USD2016 INTERNATIONAL CONFERENCE ON UNCERTAINTY IN STRUCTURAL DYNAMICS, 2279, 2286, KATHOLIEKE UNIV LEUVEN, DEPT WERKTUIGKUNDE, 2016, [Peer-reviewed]
English, International conference proceedings, High-quality fruits classified by ripeness of the fruits in a quantitative way are important for farm producers and customers. Therefore, many ripeness assessment methods, which are biochemical methods, physical methods, and optical methods, have been studied by researchers. The ripeness assessment techniques of fruits based on vibration tests have more potential because the techniques are based on non-destructive test. The ripeness of fruits is assessed by measuring natural frequencies of fruits in vibration tests, since firmness decline of fruits can be used to assess a ripeness of the fruits by past studies. In general, an impulse hammer and a shaker as contact-type excitation equipment are used in vibration tests for assessing ripeness of fruits. However, when target fruits are soft and small-sized as well as lightweight such as a grape, the implements with contact might not be used to assess the ripeness. In this paper, we measure natural frequencies of fruits in vibration tests using a shock wave generated by laser-induced plasma.

Adaptive NOX Soft Sensor for Aftertreatment of Diesel Engines
Shinichi Ishizuka, Itsuro Kajiwara, Junichi Sato, Yoshifumi Hanamura
2015 3RD INTERNATIONAL CONFERENCE ON CONTROL, MECHATRONICS AND AUTOMATION (ICCMA 2015), 42, E D P SCIENCES, 2016, [Peer-reviewed]
English, International conference proceedings, As environmental regulations become stricter, diesel engines must become cleaner. Hence, in addition to combustion control, aftertreatment of the exhaust is important to reduce emissions involving NOX and diesel particulate matter (DPM). NOX is eliminated by a chemical reaction with ammonia, which is generated by hydrolysis of injected urea. Although the NOX concentration must be accurately detected to ensure the appropriate quantity of urea is used, the response speed of the current NOX sensor is too slow to follow transient operations. In this paper, a new NOX adaptive soft sensor for aftertreatment of diesel engines is described, and its basic characteristics are confirmed via an engine bench test.

Adaptive Vibration Control Based on Pole Tuning of Model-based Controller　　　　　　　　　　　　　　　
Furuya, K, Ishizuka, S, Kajiwara, I
Proceedings of the 16th Asia Pacific Vibration Conference, 718, 724, Nov. 2015, [Peer-reviewed]
English, International conference proceedings

Development of Lamb wave visualization technology using laser
神田淳, 細矢直基, 梶原逸朗
可視化情報学会誌, 35, Suppl.2, 45‐46, 15 Sep. 2015
Japanese

Lamb wave generation using laser ablation　　　　　　　　　　　　　　　
Hosoya, N, Umino, R, Kanda, A, Kajiwara, I, Yoshinaga, A
Proceedings of International Conference on Engineering Vibration, 299, 1674, 1681, Sep. 2015, [Peer-reviewed]
English, International conference proceedings

A Composition Method for Model-free PID Control and The Convergence Characteristic　　　　　　　　　　　　　　　
Ishizuka, S, Kajiwara, I
Proceedings of the 4th Korea-Japan Joint Symposium on Dynamics & Control, 148, 150, May 2015, [Peer-reviewed]
English, International conference proceedings

Active vibration control of a membrane structure using PVDF actuator　　　　　　　　　　　　　　　
Zhang, Y, Hiruta, T, Kajiwara I, Hosoya, N
Proceedings of the 4th Korea-Japan Joint Symposium on Dynamics & Control, 163, 166, May 2015, [Peer-reviewed]
English, International conference proceedings

Viscoelastic modulus of agarose gels by magnetic resonance elastography using Micro-MRI
SUZUKI Hayato, TADANO Shigeru, GOTO Mototeru, YAMADA Satoshi, FUJISAKI Kazuhiro, KAJIWARA Itsuro, SUGA Mikio, NAKAMURA Gen
Mechanical Engineering Journal, 2, 3, 14, 00417-14-00417, The Japan Society of Mechanical Engineers, 2015, [Peer-reviewed]
English, Scientific journal, This study aimed to apply magnetic resonance elastography (MRE) using micro-magnetic resonance imaging (micro-MRI) system for the measurements of viscoelastic modulus in soft matters. The rectangular specimens of 90 × 70 × 50 mm were made of agarose gel with five kinds of stiffness by changing concentrations. The specimens were oscillated with longitudinal waves transmitted by an elastic-bar from a vibration generator in a micro-MRI system. Since the viscoelastic properties depend on the excitation frequency and amplitude, the experimental conditions were selected in the range of 50-250 Hz and 0.1-0.5 mm. The viscoelastic modulus was expressed as storage shear modulus G´ and loss shear modulus G˝. As a result, G´ increased with the frequency and amplitude, and the difference of G´ between hard and soft gels was obtained. The viscoelastic modulus of agarose gels was measured using the MRE system under the excitation conditions. Furthermore, double-layer specimens composed of 0.6 and 2.0 wt% gels were examined as an application of the MRE system. The difference of wave pattern between the hard and soft parts was observed. The values of G´ in the soft parts of the double-layer specimens corresponded to the value of the single-layer specimen, but the values of G´ in the hard parts were varied.

Online tuning of a model-based controller by perturbation of its poles
Keiichiro Furuya, Shinichi Ishizuka, Itsuro Kajiwara
JOURNAL OF ADVANCED MECHANICAL DESIGN SYSTEMS AND MANUFACTURING, 9, 2, No.15-00061, JAPAN SOC MECHANICAL ENGINEERS, 2015, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal, This study proposes an online tuning method using a model-based controller with adaptive parameters in the controller to effectively maintain the control performance and stability due to characteristic variations in the structure. Although model-based control generally provides a highly controllable performance, its performance depends on the modeling accuracy of the controlled object. Typically modeling errors, characteristics that change over time, etc. cause the performance to deteriorate. Hence, tuning of the model-based controller's characteristics is proposed as a method to adapt to the errors between a real object and its model. The main idea of the tuning method proposed in this study is that tuning the poles of the controller greatly affects control performance and stability. The tuning algorithm in the proposed method employs the simultaneous perturbation stochastic approximation (SPSA), which is well suited for optimization problems with multiple design variables. To evaluate the effectiveness of the proposed tuning method, it is applied to vibration control simulations in which the model of the controlled object is perturbed to change its physical characteristics, and then the controller is tuned to adapt to these changes. Since SPSA is a stochastic optimization method, Monte Carlo simulations are also conducted to demonstrate the effectiveness of the proposed tuning method.

Online adaptive PID control for MIMO systems using simultaneous perturbation stochastic approximation
Shinichi Ishizuka, Itsuro Kajiwara
JOURNAL OF ADVANCED MECHANICAL DESIGN SYSTEMS AND MANUFACTURING, 9, 2, No.14-00390, JAPAN SOC MECHANICAL ENGINEERS, 2015, [Peer-reviewed]
English, Scientific journal, This paper proposes a constitution method for an adaptive PID control system that follows a non-stationary system. Because a PID controller has various practical benefits that are easy to implement, unnecessary of controlled model and highly robust, it is the most common control system in industrial world even today. However, its main drawback is that tuning is time consuming because each parameter is determined empirically based on trial-and-error, which is especially noticeable in a multi-input multi-output (MIMO) system composed of multiple PID controllers with interference between control input and controlled output. Other methods have been proposed, including the Ziegler-Nichols ultimate sensitivity method, but it cannot deal with a MIMO system. Additionally, methods using optimization exist, but they cannot provide online tuning for non-stationary systems during operations due to the numerous tuning parameters and repeated computations. In this study, we introduce a computationally efficient optimization method called the Simultaneous Perturbation Stochastic Approximation (SPSA) and investigate its performances when applied to a PID control system. We also propose an online parameter tuning method for the controller by improving the standard SPSA algorithm. The efficiency of proposed method is demonstrated by applying it to a MIMO system, which has some interference.

Non-contact acoustic tests based on nanosecond laser ablation: Generation of a pulse sound source with a small amplitude
Naoki Hosoya, Itsuro Kajiwara, Tatsuo Inoue, Koh Umenai
JOURNAL OF SOUND AND VIBRATION, 333, 18, 4254, 4264, ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, Sep. 2014, [Peer-reviewed]
English, Scientific journal, A method to generate a pulse sound source for acoustic tests based on nanosecond laser ablation with a plasma plume is discussed. Irradiating a solid surface with a laser beam expands a high-temperature plasma plume composed of free electrons, ionized atoms, etc. at a high velocity throughout ambient air. The shockwave generated by the plasma plume becomes the pulse sound source. A laser ablation sound source has two features. Because laser ablation is induced when the laser fluence reaches 10(12)-10(14) W/m(2), which is less than that for laser-induced breakdown (10(15) W/m(2)), laser ablation can generate a lower sound pressure, and the sound source has a hemispherical radiation pattern on the surface where laser ablation is generated. Additionally, another feature is that laser-induced breakdown sound sources can fluctuate, whereas laser ablation sound sources do not because laser ablation is produced at a laser beam-irradiation point We validate this laser ablation method for acoustic tests by comparing the measured and theoretical resonant frequencies of an impedance tube. (C) 2014 Elsevier Ltd. All rights reserved.

Vibration control evaluation for underwater structures using non-contact laser excitation
Umenai K, Hosoya N, Kajiwara I
Proceedings of 12th International Conference on Motion and Vibration Control, 2A32, Aug. 2014, [Peer-reviewed]
English, International conference proceedings

Pole tuning of model-based controller using simultaneous perturbation stochastic approximation
Furuya K, Ishizuka S, Kajiwara I, Zhang Y
Proceedings of 12th International Conference on Motion and Vibration Control, 3B23, Aug. 2014, [Peer-reviewed]
English, International conference proceedings

Co-operative PID tuning for interference systems using Simultaneous Perturbation Stochastic Approximation
Ishizuka S, Kajiwara, I.
Proceedings of 12th International Conference on Motion and Vibration Control, 2A14, Aug. 2014, [Peer-reviewed]
English, International conference proceedings

Mechano-actuated ultrafast full-colour switching in layered photonic hydrogels
Youfeng Yue, Takayuki Kurokawa, Md Anamul Haque, Tasuku Nakajima, Takayuki Nonoyama, Xufeng Li, Itsuro Kajiwara, Jian Ping Gong
NATURE COMMUNICATIONS, 5, 4659, NATURE PUBLISHING GROUP, Aug. 2014, [Peer-reviewed]
English, Scientific journal, Photonic crystals with tunability in the visible region are of great interest for controlling light diffraction. Mechanochromic photonic materials are periodically structured soft materials designed with a photonic stop-band that can be tuned by mechanical forces to reflect specific colours. Soft photonic materials with broad colour tunability and fast colour switching are invaluable for application. Here we report a novel mechano-actuated, soft photonic hydrogel that has an ultrafast-response time, full-colour tunable range, high spatial resolution and can be actuated by a very small compressive stress. In addition, the material has excellent mechanical stability and the colour can be reversibly switched at high frequency more than 10,000 times without degradation. This material can be used in optical devices, such as full-colour display and sensors to visualize the time evolution of complicated stress/strain fields, for example, generated during the motion of biological cells.

Damage detection in membrane structures using non-contact laser excitation and wavelet transformation
Feblil Huda, Itsuro Kajiwara, Naoki Hosoya
JOURNAL OF SOUND AND VIBRATION, 333, 16, 3609, 3624, ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, Aug. 2014, [Peer-reviewed]
English, Scientific journal, In this paper, a vibration testing and health monitoring system based on an impulse response excited by laser is proposed to detect damage in membrane structures. A high power Nd: YAG pulse laser is used to supply an ideal impulse to a membrane structure by generating shock waves via laser-induced breakdown in air. A health monitoring apparatus is developed with this vibration testing system and a damage detecting algorithm which only requires the vibration mode shape of the damaged membrane. Artificial damage is induced in membrane structure by cutting and tearing the membrane. The vibration mode shapes of the membrane structure extracted from vibration testing by using the laser-induced breakdown and laser Doppler vibrometer are then analyzed by 2-D continuous wavelet transformation. The location of damage is determined by the dominant peak of the wavelet coefficient which can be seen clearly by applying a boundary treatment and the concept of an iso-surface to the 2-D wavelet coefficient. The applicability of the present approach is verified by finite element analysis and experimental results, demonstrating the ability of the method to detect and identify the positions of damage induced on the membrane structure. (C) 2014 Elsevier Ltd. All rights reserved.

MRE simulation based on finite element vibration analysis of viscoelastic model
S. Tomita, H. Suzuki, I. Kajiwara, S. Tadano, G. Nakamura, Y. Jiang
IFMBE Proceedings, 43, 43, 168, 171, Springer Verlag, 2014, [Peer-reviewed]
English, International conference proceedings, Elastogram of magnetic resonance elastography (MRE) is a technique to identify the viscoelastic parameters of biological tissue by solving inverse problem from the displacement fields inside the tissue measured by the hardware of MRE. Finite element analysis (FEA) is effective to support developing elastogram. In this study, as the forward problem of elastogram three-dimensional numerical simulation of MRE measurement is conducted by applying FEA to a viscoelastic model of tissue. Then the inverse problem of elastogram is solved by applying the modified integral method to FEA results. The accuracy of numerical simulation is verified by comparing calculated results to real data measured by MRE.

Viscoelastic properties of gel material and soft tissue measured by MRE (Magnetic Resonance Elastography) using micro MRE
Hayato Suzuki, Mikio Suga, Kazuhiro Fujisaki, Itsuro Kajiwara, Gen Nakamura, Kogo Yoshikawa, Shigeru Tadano
IFMBE Proceedings, 43, 156, 159, Springer Verlag, 2014, [Peer-reviewed]
English, International conference proceedings, Magnetic resonance elastography (MRE) was developed for detecting the region and the stage of disease by changing in the hardness of human tissue or organ. The MRE technology requires an external excitation system for generating transverse waves to the subject in the gantry of MRI. Stiffness of the organ is quantitatively calculated from the wave patterns through a mathematical model. Techniques to measure viscoelastic property of soft materials have been developed. For example, rheometer and ultrasound elastography has been generally used for gel materials and soft tissues. For example, rheometer and ultrasound elastography has been generally used for gel materials and soft tissues. Magnetic resonance elastography have an important role to measure a distribution of quantitative viscoelastic property under a keeping shape of soft material objects and an influence of frequency. In this study, we focused the viscoelastic property of gel material and soft tissue measured by the MRE based on the micro MRI (0.3 T) designed from a high-power vibration generator and a bartype vibration transmitter. The MRE represent the viscoelastic property at a complex modulus G*=G’+iG”. The storage shear modulus G’ and the loss shear modulus G” shows elasticity and viscosity, respectively. Specimens made by gelatin gel and bovine liver and muscle. We report about influence of excitation frequency that is used 62.5 to 500 Hz and specimen boundary condition that fix each plane of the specimen. The G’ of gelatin gel increase with the frequency. We will discuss about the boundary condition of the specimen and the soft tissue.

Viscoelastic properties of gel material and soft tissue measured by MRE (Magnetic Resonance Elastography) using micro MRE
Hayato Suzuki, Mikio Suga, Kazuhiro Fujisaki, Itsuro Kajiwara, Gen Nakamura, Kogo Yoshikawa, Shigeru Tadano
IFMBE Proceedings, 43, 156, 159, Springer Verlag, 2014, [Peer-reviewed]
English, International conference proceedings, Magnetic resonance elastography (MRE) was developed for detecting the region and the stage of disease by changing in the hardness of human tissue or organ. The MRE technology requires an external excitation system for generating transverse waves to the subject in the gantry of MRI. Stiffness of the organ is quantitatively calculated from the wave patterns through a mathematical model. Techniques to measure viscoelastic property of soft materials have been developed. For example, rheometer and ultrasound elastography has been generally used for gel materials and soft tissues. For example, rheometer and ultrasound elastography has been generally used for gel materials and soft tissues. Magnetic resonance elastography have an important role to measure a distribution of quantitative viscoelastic property under a keeping shape of soft material objects and an influence of frequency. In this study, we focused the viscoelastic property of gel material and soft tissue measured by the MRE based on the micro MRI (0.3 T) designed from a high-power vibration generator and a bartype vibration transmitter. The MRE represent the viscoelastic property at a complex modulus G*=G’+iG”. The storage shear modulus G’ and the loss shear modulus G” shows elasticity and viscosity, respectively. Specimens made by gelatin gel and bovine liver and muscle. We report about influence of excitation frequency that is used 62.5 to 500 Hz and specimen boundary condition that fix each plane of the specimen. The G’ of gelatin gel increase with the frequency. We will discuss about the boundary condition of the specimen and the soft tissue.

Vibration test and health monitoring of membrane structure using non-contact laser excitation
Feblil Huda, Itsuro Kajiwara, Naoki Hosoya
HEALTH MONITORING OF STRUCTURAL AND BIOLOGICAL SYSTEMS 2014, 9064, SPIE-INT SOC OPTICAL ENGINEERING, 2014, [Peer-reviewed]
English, International conference proceedings, In this paper, a vibration testing and health monitoring system based on an impulse response excited by laser-induced breakdown is proposed to detect damage on membrane structure. A health monitoring apparatus is developed with this vibration testing system and damage detecting algorithm which only requires the vibration mode shape of the damaged membrane. The vibration mode shapes of the membrane structure are analyzed by using 2-D continuous wavelet transform, and applying boundary treatment and the concept of iso-surface. The effectiveness of the present approach is verified by finite element analysis and experimental results, demonstrating the ability of the method to detect and identify the location of damages.

Robustness analysis of enhanced adaptive feed-forward cancellation
Shota Yabui, Itsuro Kajiwara, Ryohei Okita
JOURNAL OF ADVANCED MECHANICAL DESIGN SYSTEMS AND MANUFACTURING, 8, 1, 1, 12, JAPAN SOC MECHANICAL ENGINEERS, 2014, [Peer-reviewed]
English, Scientific journal, This paper presents a robustness analysis of an enhanced adaptive feed-forward cancellation (AFC) function for a control system. The AFC is known as an adaptive control method, and the adaptive algorithm can estimate a periodic disturbance. In a previous study, an enhanced AFC was developed to compensate for non-periodic disturbances. The effectiveness of the enhanced AFC there was shown with only simulation results. In this study, the stable robustness of the enhanced AFC is analyzed for a one degree of freedom system. When the enhanced AFC is implemented to around a resonant frequency, the variations in the mechanical characteristics may cause instabilities in the control system, because the performance of the enhanced AFC depends on the phase condition of the mechanical characteristics. The experimental results show that variations in the resonant frequency may cause oscillation when the enhanced AFC design does not consider this kind of variation. The study confirms that the enhanced AFC must be designed considering variations in the resonant frequency.

MRE simulation based on finite element vibration analysis of viscoelastic model
S. Tomita, H. Suzuki, I. Kajiwara, S. Tadano, G. Nakamura, Y. Jiang
IFMBE Proceedings, 43, 168, 171, Springer Verlag, 2014, [Peer-reviewed]
English, International conference proceedings, Elastogram of magnetic resonance elastography (MRE) is a technique to identify the viscoelastic parameters of biological tissue by solving inverse problem from the displacement fields inside the tissue measured by the hardware of MRE. Finite element analysis (FEA) is effective to support developing elastogram. In this study, as the forward problem of elastogram three-dimensional numerical simulation of MRE measurement is conducted by applying FEA to a viscoelastic model of tissue. Then the inverse problem of elastogram is solved by applying the modified integral method to FEA results. The accuracy of numerical simulation is verified by comparing calculated results to real data measured by MRE.

Laser excitation system for measuring frequency response function of underwater structures
N. Hosoya, I. Kajiwara, K. Umenai
PROCEEDINGS OF INTERNATIONAL CONFERENCE ON NOISE AND VIBRATION ENGINEERING (ISMA2014) AND INTERNATIONAL CONFERENCE ON UNCERTAINTY IN STRUCTURAL DYNAMICS (USD2014), 1089, 1099, KATHOLIEKE UNIV LEUVEN, DEPT WERKTUIGKUNDE, 2014, [Peer-reviewed]
English, International conference proceedings, Ocean robots that equipped with manipulator for building underwater structures and handling investigations of ocean resources have been studied. To achieve high-precision and high-speed positioning for the manipulator, its vibration caused by an additional mass effect of fluid, a drag force and a buoyant force, etc. should be evaluated by vibration tests in water in actual equipment and suppressed through this evaluation. However, the vibration tests of the underwater structures (we refer to machines and structures in water as underwater structures) to measure frequency response function are difficult. This paper proposes a method of a non-contact experimental vibration analysis using pulsed-laser ablation for the underwater structures that were completely submerged in water. The impact testing with impulse hammer is used widely for experimental vibration analysis due to the simplicity of the apparatus. However, the impact testing has limitations in use in underwater condition because it is difficult for experimenters to operate the impact hammer in water. The proposed method yields the frequency response functions by applying a pulsed-laser-ablation excitation force to the structure and measuring the output using a laser Doppler vibrometer. Since the direction, strength and effective duration of the pulsed-laser-ablation force are essentially constant, this force can be calibrated by measuring these properties in advance. Therefore input-detection-free frequency response function measurements can be realized. The results obtained in this study demonstrate the effectiveness of the present vibration test method for the underwater structures.

A Comparison Study between a Resonant Filter and an Adaptive Feed-forward Cancellation for Implementation of a Control System
Shota Yabui, Itsuro Kajiwara
2014 IEEE 13TH INTERNATIONAL WORKSHOP ON ADVANCED MOTION CONTROL (AMC), 598, 603, IEEE, 2014, [Peer-reviewed]
English, International conference proceedings, In this paper, we present a comparison study between a resonant filter and an adaptive feed-forward cancellation (AFC). To compensate for disturbances, the resonant filter decreases the gain of the sensitivity function by using the vector locus. The adaptive learning method adjusts the coefficients of the AFC to compensate for a disturbance. Each method does not make difference with respect to performance for disturbance compensation. However, important factors for constructing the control system should be also considered to implement for a control systems in addition to the performance. This paper introduces comparison study between the resonant filter and the AFC for implementation of a control system. The simulations of the disturbance compensation were conducted using an HDD Benchmark Problem as a case study. Engineers can decide which control theory is better to be implemented in the control system with reference to this study.

A study of equivalence between adaptive learning and loop shaping methods for disturbance compensation
Shota Yabui, Atushi Okuyama, Takenori Atsumi, Itsuro Kajiwara
JOURNAL OF ADVANCED MECHANICAL DESIGN SYSTEMS AND MANUFACTURING, 8, 3, 1, 14, JAPAN SOC MECHANICAL ENGINEERS, 2014, [Peer-reviewed]
English, Scientific journal, This paper introduces a theoretical analysis of the disturbance compensation methods in positioning systems. There are two major methods used to compensate for disturbances. The first one is based on a loop shaping method and the second one is based on an adaptive learning method. We make a comparison between a resonant filter used as the loop shaping method and an enhanced adaptive feed-forward cancellation (AFC) method used as the adaptive learning method. To compensate disturbances, the resonant filter decreases the gain of the sensitivity function at the disturbance frequency by using the vector locus. The adaptive learning method adjusts the coefficients of the enhanced AFC to compensate for a disturbance. We found that the LTI model of an enhanced AFC is the same as that for a resonant filter when we compared their characteristics. A simulation of the disturbance compensation in a hard disk drive showed that these time responses and frequency responses coincided. Moreover, the results showed advantages of each of the control methods with the exception of the performance. A resonant filter realizes low cost implementation with compare to an enhanced AFC. That is, a resonant filter easier to implement than an enhanced AFC. An enhanced AFC has the utility to realize a high quality function control system simultaneously able to compensate and estimate for disturbances. The results of the evaluation in this study will provide design engineers with guidelines for selecting an optimum control strategy in actual applications.

Bolt loosening analysis and diagnosis by non-contact laser excitation vibration tests
Feblil Huda, Itsuro Kajiwara, Naoki Hosoya, Shozo Kawamura
MECHANICAL SYSTEMS AND SIGNAL PROCESSING, 40, 2, 589, 604, ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, Nov. 2013, [Peer-reviewed]
English, Scientific journal, In this paper, a vibration testing and health monitoring system based on an impulse response excited by laser ablation is proposed to detect bolted joint loosening. A high power Nd: YAG pulse laser is used to generate an ideal impulse on a structural surface which offers the potential to measure high frequency vibration responses on the structure. A health monitoring apparatus is developed with this vibration testing system and a damage detecting algorithm. The joint loosening can be estimated by detecting fluctuations of the high frequency response with the health monitoring system. Additionally, a finite element model of bolted joints is proposed by using three-dimensional elements with a pretension force applied and with contact between components taken into account to support the bolt loosening detection method. Frequency responses obtained from the finite element analysis and the experiments using the laser excitation are in good agreement. The bolt loosening can be detected and identified by introducing a damage index by statistical evaluations of the frequency response data using the Recognition-Taguchi method. The effectiveness of the present approach is verified by simulations and experimental results, which are able to detect and identify loose bolt positions in a six-bolt joint cantilever. (C) 2013 Elsevier Ltd. All rights reserved.

Acoustic testing in a very small space based on a point sound source generated by laser-induced breakdown: Stabilization of plasma formation
Naoki Hosoya, Masaki Nagata, Itsuro Kajiwara
Journal of Sound and Vibration, 332, 19, 4572, 4583, 16 Sep. 2013, [Peer-reviewed]
English, Scientific journal, This paper proposes a method of acoustic testing based on a point source generated by laser-induced breakdown in air. A high-power neodymium-yttrium- aluminum-garnet pulse laser is used in this system for generating the laser-induced breakdown in acoustic fields. Plasma formation can be realized by the laser-induced breakdown if the local intensity of the laser beam reaches 1015 W/m2. The shock wave that is yielded by consuming a part of the plasma energy becomes a sound source. Assuming that the laser beam is focused to a small volume through a convex lens and the sound source by the laser induced-breakdown has nondirectional property, it is possible to create a point source with this technique. Securing the laser light path installs no device for acoustic excitation in acoustic fields. The system is validated by comparing the resonant frequencies of a very small space measured by the laser-induced breakdown and calculated by theoretical model. © 2013 Elsevier Ltd. All rights reserved.

Non-contact Vibro-acoustic Tests Based on Nano-second laser ablation　　　　　　　　　　　　　　　
Hosoya, N, Inoue, T, Kajiwara, I
Proceedings on 11th International Conference on Vibration Problems, 248, Sep. 2013, [Peer-reviewed]
English, International conference proceedings

Optimum Design and Experimental Evaluation for Smart Micro-composites by Using Laser Excitation Technique　　　　　　　　　　　　　　　
Shinya HONDA, Kazuki WATANABE, Yoshihiro NARITA, Itsuro KAJIWARA
Proceedings of the 9th International Symposium on Vibrations of Continuous Systems (ISVCS9), 28, 30, Jul. 2013, [Peer-reviewed]
English, International conference proceedings

Maximization of Vibration Control Performance for Micro Smart Composites with the Laser Excitation Technique　　　　　　　　　　　　　　　
Kazuki WATANABE, Shinya HONDA, Yoshihiro NARITA, Itsuro KAJIWARA
Proceedings of the 15th Asia Pacific Vibration Conference, M1_303B_1, USB, Jun. 2013, [Peer-reviewed]
English, International conference proceedings

Vibration measurement and monitoring of a rotating disk using contactless laser excitation
Itsuro Kajiwara, Naoki Hosoya
ASME 2013 Dynamic Systems and Control Conference, DSCC 2013, 3, American Society of Mechanical Engineers (ASME), 2013, [Peer-reviewed]
English, International conference proceedings, This paper proposes a contactless vibration testing system for rotating disks based on an impulse response excited by a laser ablation. High power YAG pulse laser is used in this system for producing an ideal impulse force on structural surface without contact. The contactless vibration testing system is composed of a YAG laser, laser Doppler vibrometer and spectrum analyzer. This system makes it possible to measure vibration characteristics of structures under operation, such as vibration measurement of a rotating disk. The effectiveness of this system is confirmed by experimental and theoretical analyses. In this paper, a platter of hard disk drive is employed as an experimental object. Vibration characteristics of a rotating and non-rotating platter are measured and compared with the results of theoretical analysis. Copyright © 2013 by ASME.

Improvement of convergence for adaptive feed-forward cancellation using variable gains in a head positioning system of hard disk drives
Shota Yabui, Itsuro Kajiwara, Shigeo Nakamura, Takenori Atsumi
Journal of Advanced Mechanical Design, Systems and Manufacturing, 7, 6, 903, 918, 2013, [Peer-reviewed]
English, Scientific journal, We present an enhanced adaptive feed-forward cancellation (AFC) with variable gains to be used in the head positioning control system of a hard disk drive (HDD). The variable gains can help to improve the convergence characteristic of the enhanced AFC after the track seeking control. Therefore, the proposed enhanced AFC can improve the transient response of the head positioning after the track seeking control. The track seeking simulation results from HDDs showed that the proposed control method compensated for the disturbances caused by the repeatable run-out (RRO) and airflowinduced vibration immediately after the track seeking control. © 2013 by JSME.

Bolted joint loosening detection by using laser excitation
Feblil Huda, Itsuro Kajiwara, Naoki Hosoya, Shozo Kawamura
HEALTH MONITORING OF STRUCTURAL AND BIOLOGICAL SYSTEMS 2013, 8695, SPIE-INT SOC OPTICAL ENGINEERING, 2013, [Peer-reviewed]
English, International conference proceedings, In this paper, the authors propose a finite element model of a simple single bolt joint that undergoes loosening in order to verify characteristic changes due to bolt loosening and develop a loose-bolt detection system. The model is created using 3D solid elements and surface-to-surface contact elements between head/nut and flange interfaces. Pretension effects and contact behavior between flanges to be joined are also taken into account. In order to validate the finite element model by experiment, vibration testing method based on non-contact impulse excitation by high-power YAG pulse laser which can produce an ideal impulse is conducted. The characteristic changes due to the bolt loosening in high frequency region can be extracted by the present laser excitation system. Finally, an approach of loose bolt detection is demonstrated by applying statistical evaluation of Recognition-Taguchi (RT) method to a six bolt cantilever which has loose bolt.

ACTIVE VIBRATION CONTROL BASED ON SELF-SENSING FOR UNKNOWN TARGET STRUCTURES BY DIRECT VELOCITY FEEDBACK WITH ADAPTIVE FEED-FORWARD CANCELLATION
Shota Yabui, Itsuro Kajiwara, Ryohei Okita
PROCEEDINGS OF THE ASME 2013 DYNAMIC SYSTEMS AND CONTROL CONFERENCE (DSCC2013), VOL. 1, 4014, AMER SOC MECHANICAL ENGINEERS, 2013, [Peer-reviewed]
English, International conference proceedings, This paper presents active vibration control based on self-sensing for unknown target structures by direct velocity feedback (DVFB) with enhanced adaptive feed-forward cancellation (AFC). AFC is known as an adaptive control method, and the adaptive algorithm can estimate a periodic disturbance. In a previous study, an enhanced AFC was developed to compensate for a non-periodic disturbance. An active vibration control based on self-sensing by DVFB can suppress mechanical resonance by using relative velocity between the voice coil actuator and a target structure. In this study, the enhanced AFC was applied to compensate disturbance for the self-sensing vibration control system. The simulation results showed the vibration control system with DVFB and enhanced AFC could suppress mechanical resonance and compensate disturbances.

Viscoelastic properties of agarose gel by MRE using micro MRI　　　　　　　　　　　　　　　
Suzuki, H, Fujiki, K, Suga, M, Nakamura, G, Haibig, W, Kajiwara, I., Tadano, S
Proceedings of World Congress on Medical Physics and Biomedical Engineering 2012, TH.07/07.3P-08, May 2012, [Peer-reviewed]
English, International conference proceedings

Vibration testing based on impulse response excited by pulsed-laser ablation: Measurement of frequency response function with detection-free input
Naoki Hosoya, Itsuro Kajiwara, Takahiko Hosokawa
JOURNAL OF SOUND AND VIBRATION, 331, 6, 1355, 1365, ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, Mar. 2012, [Peer-reviewed]
English, Scientific journal, We have developed a non-contact vibration-measurement system that is based on impulse excitation by laser ablation (i.e. laser excitation) to measure the high-frequency-vibration characteristics of objects. The proposed method makes it possible to analyse the frequency response function just by measuring the output (acceleration response) of a test object excited by pulsed-laser ablation. This technique does not require detection of the input force. Firstly, using a rigid block, the pulsed-laser-ablation force is calibrated via Newton's second law. Secondly, an experiment is conducted in which an object whose natural frequency lies in the high-frequency domain is excited by pulsed-laser ablation. The complex frequency spectrum obtained by Fourier transform of the measured response is then divided by the estimated pulsed-laser-ablation force. Finally, because of the error involved in the trigger position of the response with respect to the impulse arrival time, the phase of the complex Fourier transform is modified by accounting for the response dead time. The result is the frequency response function of the object. The effectiveness of the proposed method is demonstrated by a vibration test of an aluminium block. (C) 2011 Elsevier Ltd. All rights reserved.

Self-sensing and model-free active vibration control based on DVFB (demonstration of control method by simulation)
Shuichi Yahagi, Yusuke Sato, Itsuro Kajiwara, Masahiko Kondo
Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, 78, 793, 3104, 3117, 2012, [Peer-reviewed]
Japanese, Scientific journal, This paper proposes a method of self-sensing and model-free vibration control based on DVFB (Direct Velocity Feedback). In general. model-based control theor is applied to design control system. In this case. an accurate vibration model of the system is required to achieve an adequate vibration control performance. However, making an accurate model and designing a control system increase the workload of engineers, and installing sensors to detect structural vibration obstructs a cost reduction of control system. In this study, we consider a self-sensing vibration control strateg using a single degree-of-freedom voice coil actuator without the model of target structures. First, the self-sensing is achieved by detecting the voltage and current of the voice coil and estimating the relative velocity of the actuator. Second. the state variables containing the velocity at the point on the target stnmcture to which the actuator is connected are estimated by Kalman litter. Finally, an c\\tended DVFB control law is applied to the actuator. In this paper. effectiveness of the proposed method is validated by simulation with the controlled systems of a two degree-of-freedom and FE (Finite Element) models.

Vibration control evaluation of smart microstructures with non-contact laser excitation
Itsuro Kajiwara, Satoshi Nakamura, Yan Zhu, Naoki Hosoya
ASME 2012 5th Annual Dynamic Systems and Control Conference Joint with the JSME 2012 11th Motion and Vibration Conference, DSCC 2012-MOVIC 2012, 3, 833, 841, 2012, [Peer-reviewed]
English, International conference proceedings, Smart structures technology that uses materials such as piezoelectric elements, etc. is effective for controlling vibration in small devices. However, for micro devices, it is difficult to experimentally measure and evaluate the vibration control characteristics of the system because of the microscopic scale. Namely, it is not realistic to install an external exciter or to apply the excitation force using an impulse hammer. Therefore, in this study, the vibration property is measured and evaluated using non-contact technologies for excitation and measurement
namely, laser ablation for the excitation and a laser Doppler vibrometer as the measurement device. Since both the input excitation and the output measurement are accomplished without contact and the excitation force is easily reproducible in the same system, this technique can be used repeatedly and the measurement can be improved. Copyright © 2012 by ASME.

Non-contact vibration tests with detection-free input based on pulsed-laser ablation for underwater structures
Naoki Hosoya, Shuichi Yahagi, Itsuro Kajiwara
Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, 78, 791, 2426, 2437, 2012, [Peer-reviewed]
Japanese, Scientific journal, This paper proposes a method of a non-contact experimental vibration analysis for underwater structures by pulsed-laser ablation. The impact testing with impulse hammer is used widely for vibration analysis due to the simplicity of the apparatus. However, the impact testing has limitations in use in underwater condition because of contact method by the experimenter. The proposed method yields the frequency response functions by applying apulsed-laser- ablation excitation force to the structure and measuring the output using a laser Doppler vibrometer. Since the direction, strength and effective duration of the pulsed-laser-ablation force are essentially constant, this force can be calibrated by measuring these properties in advance. Therefore input-detection-free frequency response function measurements can be realized. The method is validated by comparing frequency response functions obtained using laser excitation with FEM. Additionally, the frequency response function obtained in underwater conditions shows that the natural frequency decreases and the amplitude is attenuated by comparing with frequency response function in air conditions.

Multidisciplinary design optimization for smart micro-composite and experimental validation by using laser excitation technique
Shinya Honda, Kazuki Watanabe, Yoshihiro Narita, Itsuro Kajiwara
ASME 2012 5th Annual Dynamic Systems and Control Conference Joint with the JSME 2012 11th Motion and Vibration Conference, DSCC 2012-MOVIC 2012, 3, 339, 347, 2012, [Peer-reviewed]
English, International conference proceedings, The present paper proposes a multidisciplinary design optimization method for smart micro-composite structures to maximize vibration suppression performance, and an innovative experimental technique with laser excitation is applied to validate numerical results. The smart structures are composed of graphite/epoxy (CFRP) composites and PZT actuators. The performance of smart structures for vibration suppression strongly depends on vibration mode shapes and PZT actuator placements. It is possible to specify vibration mode shapes for the laminated composite by varying the stacking angles of reinforcing fibers, and both fiber orientation angles and PZT placements are optimized simultaneously by using a simple Genetic Algorithm (GA) method. Then, the calculated results are validated by an experiment using laser excitation which excites the micro-sized structures with high reproducibility since the laser is precisely irradiated to the structure at same position with same power repeatedly. Copyright © 2012 by ASME.

Excitation System for Magnetic Resonance Elastography Using Micro MRI
TADANO Shigeru, FUJISAKI Kazuhiro, SUZUKI Hayato, TAKAO Seishin, SUGA Mikio, KAJIWARA Itsuro, YAMAMOTO Toru, JIANG Yu, NAKAMURA Gen
Journal of Biomechanical Science and Engineering, 7, 4, 463, 474, The Japan Society of Mechanical Engineers, 2012, [Peer-reviewed]
English, Scientific journal, Magnetic resonance elastography (MRE) is a nondestructive method for measuring the hardness and softness of living tissue by means of magnetic resonance imaging (MRI) coupled with mechanical excitation of the subject. The shear modulus of a tissue is related to the velocity of transverse waves propagating through it, and local movements are obtained from MRI phase images. Micro MRI systems are available for high-resolution MRE measurements of soft materials. Longitudinal waves are effective for long-distance wave propagation from small excitation areas in micro MRI systems, and the transverse waves produced by the longitudinal waves can be used for elastography. This study proposes an excitation system comprising a high-power vibration generator and bar-shaped vibration transmitter made from an elastic material. The transmission characteristics of the glass-fiber-reinforced plastic bar-shaped transducer were evaluated by measuring the accelerations at its base and tip. The performance of the excitation system, which focused on the effects of frequency and amplitude, was investigated for measuring storage and loss modulus distributions in agarose gel. This system could transfer longitudinal waves with an amplitude of 0.5 mm and frequency between 50 and 250 Hz, without significant damping. Moreover, the excitation capabilities for gel phantoms were evaluated by MRE using 0.3T micro MRI equipment. A large amplitude of 0.5 mm and high frequency of 250 Hz produced less data scatter than smaller amplitudes and lower frequencies. MRE performance improved upon using strong excitations.

EGR-VNT cooperative control of diesel engine based on ILQ design
Chiaki Nishidome, Junichi Satoh, Itsuro Kajiwara, Yoshifumi Hanamura, Hiroshi Takata
Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, 78, 785, 114, 125, 2012, [Peer-reviewed]
Japanese, Scientific journal, The development of a clean and fuel efficient diesel engine control method is required for the purpose of global environmental protection. However, in the EGR control of turbo-charged engines, the system has nonlinear characteristics, and there is mutual interference between the EGR valve and the VNT guide vane. We propose a cooperative control method to deal with the nonlinearity of the diesel engine. In this paper, a method for model identification and ILQ (Inverse Linear Quadratic) design is introduced. As the result of using this method, which can be systemized from model identification to the mapping of the controller gain, high environmental performance and efficiency are achieved. © 2012 The Japan Society of Mechanical Engineers.

Acoustic vibration testing in a micro-space based on a point source generated by laser-induced breakdown
Naoki Hosoya, Masaki Nagata, Itsuro Kajiwara
Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, 78, 787, 770, 782, 2012, [Peer-reviewed]
Japanese, Scientific journal, This paper proposes a method of acoustic vibration testing based on a point source generated by laser-induced breakdown in the air. A high-power Nd: YAG pulse laser is used in this system for generating the laser-induced breakdown in acoustic fields. Plasma formation can be realized by the laser-induced breakdown if the local intensity of the laser beam reaches 10 15 W/m 2. The shock wave that is yielded by consuming a part of the plasma energy becomes a sound source. Assuming that the laser beam is focused to a small volume through a convex lens and the sound source by the laser induced-breakdown has nondirectional property, it is possible to create a point source with this technique. Securing the laser light path installs no device for acoustic excitation in acoustic fields. The system is validated by comparing the resonant frequencies of a micro-space measured by the laser-induced breakdown and calculated by theoretical model. © 2012 The Japan Society of Mechanical Engineers.

Acoustic testing in a micro-space based on a point source generated by laser-induced breakdown
N. Hosoya, M. Nagata, I. Kajiwara
PROCEEDINGS OF INTERNATIONAL CONFERENCE ON NOISE AND VIBRATION ENGINEERING (ISMA2012) / INTERNATIONAL CONFERENCE ON UNCERTAINTY IN STRUCTURAL DYNAMICS (USD2012), 49, 58, KATHOLIEKE UNIV LEUVEN, DEPT WERKTUIGKUNDE, 2012, [Peer-reviewed]
English, International conference proceedings, This paper proposes a method of acoustic testing based on a point source generated by laser-induced breakdown in the air. A high-power Nd: YAG pulse laser is used in this system for generating the laser-induced breakdown in acoustic fields. Plasma formation can be realized by the laser-induced breakdown if the local intensity of the laser beam reaches 10(15) W/m(2). The shock wave that is yielded by consuming a part of the plasma energy becomes a sound source. Assuming that the laser beam is focused to a small volume through a convex lens and the sound source by the laser-induced breakdown has nondirectional property, it is possible to create a point source with this technique. Securing the laser light path installs no device for acoustic excitation in acoustic fields.

Loose Bolt Detection by high frequency vibration measurement with non-contact laser excitation
Kajiwara, I., Miyamoto, D, Hosoya, N, Nishidome, C
Journal of System Design and Dynamics, 5, 8, 1559, 1571, The Japan Society of Mechanical Engineers, Dec. 2011, [Peer-reviewed]
English, Scientific journal, This paper proposes a vibration testing and health monitoring system based on an impulse response excited by a laser ablation. High power YAG pulse laser is used for producing an ideal impulse force on structural surface. It is possible to measure high frequency vibration responses in this system. A health monitoring system is constructed by this vibration testing system and a damage detecting algorithm. A microscopic damage of structures can be extracted by detecting fluctuations of high frequency vibration response with the present health monitoring system. In this study, loosening of bolt tightening torques is defined as the damage of the system. The damage is detected and identified by statistical evaluations of measured frequency response data with Recognition-Taguchi method. The effectiveness of the present approach is verified by experiment to detect and identify the loosening of bolts installed on an aluminum block structure.

Vibration testing based on impulse response excited by laser ablation
Itsuro Kajiwara, Naoki Hosoya
JOURNAL OF SOUND AND VIBRATION, 330, 21, 5045, 5057, ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, Oct. 2011, [Peer-reviewed]
English, Scientific journal, This paper proposes an innovative vibration testing method based on impulse response excited by laser ablation. In conventional vibration testing using an impulse hammer, high-frequency elements of over tens of kilohertz are barely present in the excitation force. A pulsed high-power YAG laser is used in this study for producing an ideal impulse force on a structural surface. Illuminating a point on a metal with the well-focused YAG laser, laser ablation is caused by generation of plasma on the metal. As a result, an ideal impulse excitation force generated by laser ablation is applied to the point on the structure. Therefore, it is possible to measure high-frequency FRFs due to the laser excitation. A water droplet overlay on the metal is used to adjust the force magnitude of laser excitation. An aluminum block that has nine natural frequencies below 40 kHz is employed as a test piece. The validity of the proposed method is verified by comparing the FRFs of the block obtained by the laser excitation, impulse hammer, and finite element analysis. Furthermore, the relationship between accuracy of FRF measurements and sensitivity of sensors is investigated. (C) 2011 Elsevier Ltd. All rights reserved.

Multidisciplinary Design Optimization for Vibration Control of Smart Laminated Composite Structures
Shinya Honda, Itsuro Kajiwara, Yoshihiro Narita
JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES, 22, 13, 1419, 1430, SAGE PUBLICATIONS LTD, Sep. 2011, [Peer-reviewed]
English, Scientific journal, The structure and vibration control system of smart laminated composites consisting of graphite-epoxy composites and piezoelectric actuators are designed for optimum vibration suppression. The placement of piezoelectric actuators, the lay-up configurations of laminated composite plates, and the H(2) control system are employed as design variables and they are optimized simultaneously by a simple genetic algorithm. To reduce complexity, only pre-selected families of lay-up configurations are considered. An objective function is the H(2) performance with respect to the controlled response for vibration suppression. A multidisciplinary design optimization is performed with the above three design variables and then the output feedback system is reconstructed with a dynamic compensator based on a linear matrix inequality approach. The validity of the modeling and calculation technique is confirmed experimentally. Optimization results show that optimized smart composites with the present approach successfully realize vibration suppression and it is confirmed that the proposed multidisciplinary design optimization technique enhances the vibration suppression of smart composites.

Design of smart composite for vibration suppression using lamination parameters
Honda S, Kosaka K, Narita Y, Kajiwara I
Proceedings of ICCM International Conferences on Composite Materials, IF0541, Aug. 2011, [Peer-reviewed]
English, International conference proceedings

Vibration Testing Method of Smart Micro-Composite with Laser Excitation
Shinya Honda, Yoshihiro Narita, Itsuro Kajiwara, Satoshi Nakamura
DYNAMICS FOR SUSTAINABLE ENGINEERING, 2011, VOL 3, 1462, 1470, HONG KONG POLYTECHNIC UNIV, 2011, [Peer-reviewed]
English, International conference proceedings, A vibration testing method for a micro-sized smart composite device using a noncontact excitation technology of the laser ablation is presented in this study. A smart structure consists of graphite/epoxy composites and piezoelectric actuators. There is a difficulty in exciting micro-devices experimentally by an impulse hammer or external exciter due to limitations on size and their high natural frequencies, resulting in an ineffective vibration evaluation. The laser ablation technology with pulse laser makes it possible to excite the structure without making a physical contact with devices and it generates a sharper impulse force than the physical contact. The experimental results showed that the present technique excites smart micro-composite accurately ranging to the high frequency region with high reproducibility and the smart micro-composite indicates specified performance of vibration control. This reveals that the laser ablation technique is suitable for the testing method of smart micro-composites.

Simultaneous Remote Energy Supply and Motion Control of Micro Vehicles with Laser
Kajiwara, I, Harada, H
Journal of System Design and Dynamics, 5, 6, 1202, 1213, The Japan Society of Mechanical Engineers, 2011, [Peer-reviewed]
English, Scientific journal, This paper proposes a method for simultaneous laser energy transmission and motion control of micro vehicles. Both the energy transmission and the remote control are achieved simultaneously with the same light path of two lasers. A green laser and a laser diode are used independently for the navigation and the energy transmission, respectively. Core technology of the system is the laser tracking, in which the direction of the tracking laser beam is changed by a galvano mirror so as to keep chasing the position of the corner-cube reflector mounted on the vehicle. In addition, by using a pulsing oscillation of the tracking laser, the vehicle is able to receive operation commands as a frequency change of the pulse. A beam of the laser diode runs parallel to the tracking beam and is radiated to the solar cells mounted on the vehicle. Then the photoelectrically converted power is supplied for the DC motors and control circuits on the vehicle. Experiments with a small wheeled-vehicle were conducted, and the results show that proposed system exhibits sufficient performance for controlling and supplying power to the micro vehicle.

Vibration testing based on impulse response excited by laser ablation (Input sensorless FRF measurements)
Hosoya N, Kajiwara, I., Hosokawa T
Transactions of the Japan Society of Mechanical Engineers Series C, 77, 773, 102, 113, The Japan Society of Mechanical Engineers, 2011, [Peer-reviewed]
Japanese, Scientific journal, The authors have proposed an analyzing method for vibration testing based on impulse excitation by laser ablation in order to experimentally identify dynamic characteristics of micro devices such as HDD head actuators or MEMS that have in the high frequency region the natural frequencies of a few tens of kilohertz. This paper proposes a method that makes it possible to analyze FRF by only measuring the output (acceleration response) in a laser excitation experiment. This enables the measurement of the force input sensorless. First, the laser excitation force is normalized by Newton's second law using a rigid block. Next, the laser excitation experiment with an object structure having a natural frequency within the high frequency region is conducted. Complex Fourier spectrum obtained by Fourier transforming the measured response is divided by the estimated laser excitation force. Finally, since the trigger position of the response and the time the impulse input is actually applied have errors, phase characteristics of the force-regulated complex Fourier transform is modified by taking the dead time included in the response into account, resulting in the FRF of the structure. The effectiveness of the proposed method is demonstrated by the vibration test with an aluminum block as object structure.

Vibration test for membrane structures using non-contact laser excitation system in vacuum environment
Kajiwara I, Obara K
Transactions of the Japan Society of Mechanical Engineers Series C, 77, 779, 2662, 2672, The Japan Society of Mechanical Engineers, 2011, [Peer-reviewed]
Japanese, Scientific journal, This paper proposes an innovative vibration testing method for membrane structures based on impulse response excited by laser. Non-contact impulse force is generated by irradiating a high power pulse laser to a structure. The laser excitation makes a precise measurement of the frequency response in wide frequency range possible because an ideal impulse force is applied to a point on the structure. Using a laser Doppler vibrometer to detect a response of the structure, both non-contact laser excitation and measurement are achieved in the vibration testing system. Furthermore, a vibration measurement of the membrane structure in vacuum environment is effectively conducted by using the proposed vibration testing method with a vacuum chamber. The validity of the present vibration testing system is verified by evaluating the measured data of the membrane structure in the vacuum chamber.

Vibration measurement for rotating disk using contactless laser excitation
Daisuke Miyamoto, Itsuro Kajiwara, Naoki Hosoya
Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, 77, 784, 4402, 4412, 2011, [Peer-reviewed]
Japanese, Scientific journal, This paper proposes a contactless vibration testing system for rotating disks based on an impulse response excited by a laser ablation. High power YAG pulse laser is used in this system for producing an ideal impulse force on structural surface without contact. The contactless vibration testing system is composed of a YAG laser, laser Doppler vibrometer and spectrum analyzer. This system makes it possible to measure vibration characteristics of structures under operation, such as vibration measurement of a rotating disk. The effectiveness of this system is confirmed by experimental and theoretical analyses. In this paper, a platter of hard disk drive is employed as an experimental object. Vibration characteristics of a rotating and non-rotating platter are measured and compared with the results of theoretical analysis. © 2011 The Japan Society of Mechanical Engineers.

Vibration control of hdd smart head actuator with pzt element
Nakamura S, Kajiwara I, Arisaka T
Transactions of the Japan Society of Mechanical Engineers Series C, 77, 775, 847, 857, The Japan Society of Mechanical Engineers, 2011, [Peer-reviewed]
Japanese, Scientific journal, The head positioning accuracy of the hard disk drive should be improved to meet today's increasing performance demands. Vibration suppression of the arm in the hard disk drive is very useful to enhance the servo bandwidth of the head positioning system. In this study, the smart structure is introduced into the hard disk drive to suppress the vibration. First, the proof-mass actuator and the tabular PZT actuator are designed, and then the experimental set-up of the smart head actuator is developed by installing the actuators for vibration control on the objective head actuator. Second, the state-space modeling of the system is conducted by system identification approach in the experimental modal analysis for control system design. Next, the vibration controller is obtained by conducting the H_∞ control problem. Finally, the closed-loop performance is evaluated by simulation and experiment.

Vibration control evaluation of micro smart structures with non-contact laser excitation
Satoshi Nakamura, Yan Zhu, Itsuro Kajiwara, Naoki Hosoya
Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, 77, 784, 4413, 4424, 2011, [Peer-reviewed]
Japanese, Scientific journal, Smart structures technology that uses piezoelectric element etc. is effective for the vibration control of small devices. However, for micro devices, it is difficult to experimentally measure and evaluate the vibration control characteristics of the system due to its microscopic scale. Namely, it is not realistic to install an external exciter or to apply the excitation force with an impulse hammer. Therefore, in this study, the vibration property is measured and evaluated by using the non-contact excitation/measurement technology using laser ablation for the excitation and laser Doppler vibrometer for the measurement. Since both input excitation and output measurement are made without contact of apparatus and the excitation force has a high reproducibility in the present system, the efficiency and the reliability of the measurement can be improved. © 2011 The Japan Society of Mechanical Engineers.

Structural health monitoring by high frequency vibration measurement with non-contact laser excitation
I. Kajiwara, D. Miyamoto, N. Hosoya, C. Nishidome
HEALTH MONITORING OF STRUCTURAL AND BIOLOGICAL SYSTEMS 2011, 7984, SPIE-INT SOC OPTICAL ENGINEERING, 2011, [Peer-reviewed]
English, International conference proceedings, This paper proposes a vibration testing and health monitoring system based on an impulse response excited by a laser ablation. High power YAG pulse laser is used for producing an ideal impulse force on structural surface. It is possible to measure high frequency vibration responses in this system. A health monitoring system is constructed by this vibration testing system and a damage detecting algorithm. A microscopic damage of structures can be extracted by detecting fluctuations of high frequency vibration response with the present health monitoring system. In this study, loosening of bolt tightening torques is defined as the damage of the system. The damage is detected and identified by statistical evaluations with Recognition-Taguchi method.

Health monitoring based on high frequency vibration measurement with laser
Miyamoto D, Kajiwara I, Hosoya N, Nishidome C
Transactions of the Japan Society of Mechanical Engineers Series C, 77, 777, 1760, 1771, 2011, [Peer-reviewed]
Japanese, Scientific journal

Remote motion control of micro vehicles by two-way laser communication technology
Itsuro Kajiwara, Kosuke Nakano, Hiroyuki Harada
Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, 76, 765, 1232, 1239, Japan Society of Mechanical Engineers, 2010, [Peer-reviewed]
Japanese, Scientific journal, A remote motion control method for micro vehicles by two-way laser communication technology is proposed in this paper. The vehicle receives operation commands as pulse frequency modulations of a pulse laser radiated from the light source base. The laser is also used for laser tracking to chase the position of the corner-cube reflector equipped on the vehicle. At the same time, the vehicle sends its position information to the base with a MEMS (Micro-Electric-Mechanical-Systems) mirror equipped on the vehicle. The MEMS mirror transmits the information signal as light-path frequency modulations of the reflected laser beam. An advantage of this system is that the all these functions are achieved by a single laser source, resulting in the simplicity of the mechanism and the weight reduction of the micro vehicle. An experiment with a wheeled vehicle is carried out and the effectiveness of the proposed system is verified by achieving the motion control of the vehicle.

VIBRATION MEASUREMENTS FOR MEMBRANE STRUCTURES BY USING LASER EXCITATION SYSTEM
Kenya Obara, Itsuro Kajiwara
PROCEEDINGS OF THE ASME CONFERENCE ON SMART MATERIALS, ADAPTIVE STRUCTURES AND INTELLIGENT SYSTEMS, 2010, VOL 2, 3617, 559, 564, AMER SOC MECHANICAL ENGINEERS, 2010, [Peer-reviewed]
English, International conference proceedings, The purpose of this study is to establish a measurement method to get vibration characteristics of membrane structures. An impulse hammer or a vibration exciter have been traditionally used to measure the vibration response of constructions and mechanical systems, but this method is not appropriate to apply the impulse force for the membrane structures due to its lightness and flexibility. Consequently, non-contact impulse excitation is applied by using laser excitation system and is absolutely suitable for the vibration measurement of the membrane structures. The proposed method makes the precise measurement of the frequency response in wide frequency range possible because an ideal impulse force is applied to a point on the structure. Moreover, a health monitoring system can be constructed by combining this vibration testing system and damage detection system. Damage of structures can be identified by detecting fluctuations of vibration responses with this health monitoring system.

Remote motion control of micro vehicles by two-way laser communication technology
Kajiwara I, Nakano K, Harada H
Journal of System Design and Dynamics, 4, 6, 941, 952, The Japan Society of Mechanical Engineers, 2010, [Peer-reviewed]
English, Scientific journal, A novel remote-control method for micro vehicles based on two-way laser communication is proposed. The vehicle receives operational commands in the frequency changes of a pulsed-laser. The laser also plays a role in tracking the vehicle by following the position of a corner-cube reflector equipped on the vehicle. At the same time, the vehicle returns information by means of a MEMS mirror equipped on the vehicle; the mirror transmits information as frequency changes in the light-path vibrations of the reflected laser-beam. The advantage of this system is that the all of these communication functions are achieved by a single laser beam; and the proposed method will contribute to simplify the mechanism and reduce the weight of micro vehicles. An experiment with a small wheeled-vehicle was conducted, and the results show that the concept exhibits a sufficiently accurate performance to control micro vehicles.

MULTIDISCIPLINARY DESIGN OPTIMIZATION OF ACTUATOR ARRANGEMENTS, LAY-UP CONFIGURATIONS AND CONTROL SYSTEMS FOR SMART LAMINATED COMPOSITE STRUCTURES
Shinya Honda, Itsuro Kajiwara, Yoshihiro Narita
PROCEEDINGS OF THE ASME CONFERENCE ON SMART MATERIALS, ADAPTIVE STRUCTURES AND INTELLIGENT SYSTEMS, 2010, VOL 2, 3661, 315, 321, AMER SOC MECHANICAL ENGINEERS, 2010, [Peer-reviewed]
English, International conference proceedings, Structures and control systems of smart laminated composites consisting of graphite-epoxy composites and piezoelectric actuators are designed optimally for the vibration suppression. Placements of piezoelectric actuators, lay-up configurations of laminated composite plates and the H-2 control system are employed as design variables and are optimized simultaneously by a simple genetic algorithm (SGA). An objective function is H-2 performance with assuming that the state feedback is available. A multidisciplinary design optimization is performed with above three design variables and then the output feedback system is reconstructed with the dynamic compensator based on the linear matrix inequality (LMI) approach. Optimization results show that the optimized smart composite successfully realizes vibration suppression of the system and it is confirmed that the present multidisciplinary design optimization technique is quite efficient to the smart composites.

Input Sensorless FRF Measurements by Laser Excitation System
N. Hosoya, I. Kajiwara, T. Hosokawa
PROCEEDINGS OF ISMA2010 - INTERNATIONAL CONFERENCE ON NOISE AND VIBRATION ENGINEERING INCLUDING USD2010, 1747, 1757, KATHOLIEKE UNIV LEUVEN, DEPT WERKTUIGKUNDE, 2010, [Peer-reviewed]
English, International conference proceedings, The authors have been proposed an analyzing method for vibration testing based on impulse excitation by laser ablation in order to experimentally identify dynamic characteristics of micro devices such as HDD head actuators or MEMS that have in the high frequency region the natural frequencies of a few tens of kilohertz. This paper proposes a method that makes it possible to analyze FRF by only measuring the output (acceleration response) in a laser excitation experiment. This enables the measurement of the force input sensorless. First, the laser excitation force is normalized by Newton's second law using a rigid block. Next, the laser excitation experiment with an object structure having a natural frequency within the high frequency region is conducted. Complex Fourier spectrum obtained by Fourier transforming the measured response is divided by the estimated laser excitation force. Finally, since the trigger position of the response and the time the impulse input is actually applied have errors, phase characteristics of the force-regulated complex Fourier transform is modified by taking the dead time included in the response into account, resulting in the FRF of the structure. The effectiveness of the proposed method is demonstrated by the vibration test with an aluminum block as object structure.

Laser Excitation System for Measuring Frequency Response Function of High Frequency Vibration　　　　　　　　　　　　　　　
Hosoya, N, Kajiwara, I
Proceedings of 13th Asia-Pacific Vibration Conference, P84, Nov. 2009, [Peer-reviewed]
English, International conference proceedings

Optimization of smart structure for improving servo performance of hard disk drive
Masafumi Takahashi, Itsuro Kajiwara, Toshihiro Arisaka
Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, 75, 753, 1369, 1376, Japan Society of Mechanical Engineers, 2009, [Peer-reviewed]
Japanese, Scientific journal, The head positioning accuracy of the hard disk drive (HDD) should be improved to meet today's increasing performance demands. Vibration suppression of the arm in the hard disk drive is very important to enhance the servo bandwidth of the head positioning system. In this study, the smart structure is introduced into the hard disk drive to suppress the vibration. It has been expected that technology of smart structure will contribute to the development of small and light-weight mechatronics devices with the required performance. First, modeling of the system is conducted with finite element method (FEM) and modal analysis. Next, the actuator location and the control system are simultaneously optimized using genetic algorithm (GA). Vibration control effect with the proposed vibration control mechanisms has been evaluated by some simulations.

Vibration testing based on impulse response excited by laser ablation
Naoki Hosoya, Itsuro Kajiwara, Hitoshi Sorimachi
Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, 75, 760, 3160, 3167, Japan Society of Mechanical Engineers, 2009, [Peer-reviewed]
Japanese, Scientific journal, This paper proposes a vibration testing system based on an impulse response excited by a laser ablation. In conventional vibration testing using an impulse hammer, high frequency elements of over tens of kilohertz are barely present in the excitation force. A high-power YAG pulse laser is used in this system for producing an ideal impulse force on a structural surface. By illuminating a point on a metal with a well-focused (2 μn) YAG laser, atoms, electrons and ions etc. are emitted from the metal. As a result, an ideal impulse excitation force generated by laser ablation is applied to a point on the structure. Therefore, it is possible to measure high frequency FRFs (Frequency Response Functions) in this system. Additionally, a water droplet overlay on the metal is used to adjust the force magnitude of laser excitation. An aluminum block that has nine natural frequencies below 40 kHz is employed as a test piece. The system is validated by comparing the FRFs of the block obtained using laser excitation, an impulse hammer, and FEM. In addition, the relationship between accuracy of FRF measurements and sensitivity of sensors is investigated.

Vibration Control of Hard Disk Drive with Smart Structure Technology for Improving Servo Performance
Itsuro Kajiwara, Toshio Uchiyama, Toshihiro Airisaka
MOTION AND VIBRATION CONTROL, 165, +, SPRINGER, 2009, [Peer-reviewed]
English, International conference proceedings, In hard disk drives, vibration suppression is very important to boost the servo performance for achieving the enhanced density of the disk and following precision of the system, It has been expected that technology of smart structure will contribute to the development of small and light-weight mechatronics devices with the required performance. This study proposes a new vibration control mechanism with smart structures technology in order to achieve significant vibration suppression in hard disk drive systems, First, modeling of the system is conducted with finite element and modal analyses. Next, the control system design and closed-loop simulation are performed with the proposed vibration control mechanism composed of piezoelectric sensors and actuators. Finally, a multidisciplinary design optimization on actuator location and control system is examined to enhance the closed-loop performance of the system.

Optimization of smart structure for improving servo performance of hard disk drive
Kajiwara, I., Takahashi, M, Arisaka, T
Journal of System Design and Dynamics, 3, 6, 906, 917, The Japan Society of Mechanical Engineers, 2009, [Peer-reviewed]
English, Scientific journal, Head positioning accuracy of the hard disk drive should be improved to meet today's increasing performance demands. Vibration suppression of the arm in the hard disk drive is very important to enhance the servo bandwidth of the head positioning system. In this study, smart structure technology is introduced into the hard disk drive to suppress the vibration of the head actuator. It has been expected that the smart structure technology will contribute to the development of small and light-weight mechatronics devices with the required performance. First, modeling of the system is conducted with finite element method and modal analysis. Next, the actuator location and the control system are simultaneously optimized using genetic algorithm. Vibration control effect with the proposed vibration control mechanisms has been evaluated by some simulations.

Vibration Control of Smart Structures with Dynamic Characteristic Variation
ITSURO KAJIWARA, RYO TSUCHIYA
Journal of System Design and Dynamics, 2, 1, 413, 424, The Japan Society of Mechanical Engineers, 2008
English, Scientific journal, This study is concerned with a vibration control strategy for a flexible-link system to achieve effective vibration suppression. It is required that the control system adapts to the dynamic characteristic variation of the system. A smart-link system composed of piezoelectric actuators and gain-scheduled controller is proposed to cope with change of the variable parameters which causes the dynamic characteristic variation of the system. An adaptive control is conducted by scheduling some LTI controllers to keep the stability and performance against the change of the variable parameters. The appropriate actuator location is determined by the target mode shapes. The scheduling gains for the LTI controllers designed at their operating points are optimized to obtain effective vibration suppression of the system.

Gain-scheduled control of smart link system with dynamic characteristic variation
Kajiwara I, Tsuchiya R, Ishizuka S
Proceedings of 19th International Conference on Adaptive Structures and Technologies 2008, ICAST 2008, 718, 729, 2008, [Peer-reviewed]
English, International conference proceedings

Piezoelectric and control optimisation of smart structures for vibration and sound suppression
Kimiaki Ono, Itsuro Kajiwara
INTERNATIONAL JOURNAL OF VEHICLE DESIGN, 43, 1-4, 184, 199, INDERSCIENCE ENTERPRISES LTD, 2007, [Peer-reviewed]
English, Scientific journal, This paper proposes a multidisciplinary design optimisation of smart structures for vibration and sound suppression. The smart structure consists of a panel with one fixed end, two piezoelectric actuators and a control system. The control system is designed according to the H-2 specification with a reduced-order modal model derived from FEM and modal analysis. The sound pressure level of sound radiation from the vibrating panel is calculated by BEM. The design problem for improving the H-2 performance is defined and then the piezoelectric actuators and the control system are simultaneously optimised by the presented approach, resulting in an enhanced performance for the vibration and sound suppression.

Design of active control system for combustion instability using H-2 algorithm
Hiroyuki Sato, Chiaki Nishidome, Itsuro Kajiwara, A. Koichi Hayashi
INTERNATIONAL JOURNAL OF VEHICLE DESIGN, 43, 1-4, 322, 340, INDERSCIENCE ENTERPRISES LTD, 2007, [Peer-reviewed]
English, Scientific journal, An active control system of oscillatory flame in a swirler combustor was investigated to control flame stability and to reduce the combustion noise. A modem H-2 control algorithm based on experimental modal analysis for system identification was applied to develop a closed-loop feedback control system. To examine the exothermic fluctuation, planar laser-induced fluorescence measurements were carried out. The OH radical distribution near the region of the flame holder was visualised. Two types of oscillatory flame were observed in this investigation: one was characterised by low-frequency mode; the other, with high-frequency mode, was produced with a remarkable frequency characterised by resonance of the combustor. As for the closed-loop feedback control system, a loudspeaker and microphone were used as an actuator and a sensor. It was found that the developed control system performed well with the result of 15-dB reduction.

Broadband robust controller design of multi-frequency-band parallel control system
Kajiwara, I., Kato H, Kondo M, Sato Y
Transactions of the Japan Society of Mechanical Engineers Series C, 73, 732, 2246, 2254, The Japan Society of Mechanical Engineers, 2007, [Peer-reviewed]
Japanese, Scientific journal, This paper proposes an approach on broadband robust controller design of multi-frequency-band parallel control system in order to achieve a significant vibration reduction in broadband frequency range. Mechanical systems usually have vibration and noise problems in various frequency ranges. A complex high-order modeling has to be conducted to control the vibration and noise in broadband frequency range. In this case, the modeling error is generally increased, resulting in a degradation of control performance. This study designs the multiple subcontrollers based on the multiple sub-models derived in the corresponding frequency ranges. The order of each sub-model becomes small and so the modeling accuracy is improved. The total controller is constructed as the parallel circuit with each sub-controller designed in each frequency range. Each sub-controller is designed to satisfy the closed-loop stability against the interference to other sub-controllers in this study. It is verified that the calculation efficiency and control performance can be enhanced by the proposed control strategy.

Active control of combustion oscillations in a lean premixed gas-turbine combustor
Shigeru Tachibana, Laurent Zimmer, Yoji Kurosawa, Kazuo Suzuki, Hiroyuki Sato, A. Koichi Hayashi, Chiaki Nishidome, Itsuro Kajiwara
INTERNATIONAL JOURNAL OF VEHICLE DESIGN, 43, 1-4, 306, 321, INDERSCIENCE ENTERPRISES LTD, 2007, [Peer-reviewed]
English, Scientific journal, Active control of combustion oscillations occurring in a methane-air lean premixed model combustor is accomplished by the method of secondary fuel injection. The main flame is sustained by an axial vane swirler. The central part of the swirler is endowed a function as the secondary fuel injector. The fuel jets from the injector enhance the flame stability by producing rich stable flames in the region of the flame base. Open-loop controls by secondary fuel injection with constant flow rates have been conducted on a naturally unstable condition. The results show sensitivity to the injection amount. It indicates that the flame base is very sensitive to the additional fuel distribution. A similar discussion is made on NOx emission also. Finally, a closed-loop control has been performed by implementing the mixed H-2/H-infinity controller. An obvious effect of the closed-loop control on the suppression of pressure oscillations is found without loosing an advantage for low NOx emissions.

Gain-scheduled control of smart structures with dynamic characteristic variation
Kajiwara I, Tsuchiya R
Proceedings of the World Forum on Smart Materials and Smart Structures Technology, 453, 2007, [Peer-reviewed]
English, International conference proceedings

Tracking control and system development for laser-driven micro-vehicles
Itsuro Kajiwara, Kentaro Hoshino, Shinji Hara, Daisuke Shiokata, Takashi Yabe
Transactions of the Japan Society for Aeronautical and Space Sciences, 49, 164, 71, 76, 2006
English, Scientific journal, The purpose of this paper is to design a control system for an integrated laser propulsion/tracking system to achieve continuous motion and control of laser-driven micro-vehicles. Laser propulsion is significant in achieving miniature and light micro-vehicles. A laser-driven micro-airplane has been studied using a paper airplane and YAG laser, resulting in successful gliding of the airplane. High-performance laser tracking control is required to achieve continuous flight. This paper presents a control design strategy based on the generalized Kalman-Yakubovic-Popov lemma to achieve this requirement. Experiments have been carried out to evaluate the performance of the integrated laser propulsion/tracking system. © 2006 The Japan Society for Aeronautical and Space Sciences.

Remote control of laser-driven micro-vehicles
Tetsuya Okita, Kentaro Hoshino, Itsuro Kajiwara
BEAMED ENERGY PROPULSION, 830, 553, +, AMER INST PHYSICS, 2006, [Peer-reviewed]
English, International conference proceedings, The LPFM (Laser Pulse Frequency Modulation) laser control approach for laser-driven micro-vehicles is presented and die integrated laser propulsion/tracking/control system is developed in this study. The laser propulsion has been studied to achieve the lightened and miniaturized vehicles. The laser tracking using corner cube reflector that is widely used in free space communications is expected as a key technology to achieve continuous propulsion. The laser control is remotely conducted by sending the commands to the vehicle with laser. Since each laser pulse frequency is instantaneously transformed into the command with the laser beam and phototransistor, high speed positioning is achieved with the presented LPFM laser control system ne use of three different laser wavelengths and dielectric mirrors makes it possible to integrate die laser propulsion, tracking and control systems. First, the constitution and function of LPFM laser control to laser-driven micro-vehicles is shown and the integrated laser propulsion/tracking/control system is developed. Next, experiments with a miniature vehicle am carried out to confirm the performance of the developed system.

Optimization of vibration control system for smart structures with disturbance characteristic variation
Ono K, Kajiwara I
Proceedings of 11th AIAA/ISSMO Multidisciplinary Analysis and Optimization Conference, AIAA-2006-7046, 2006, [Peer-reviewed]
English, International conference proceedings

Integrated optimization of actuator array and adaptive control for smart structures
Tsuchiya R, Kajiwara, I.
Transactions of the Japan Society of Mechanical Engineers Series C, 72, 713, 53, 60, 2006, [Peer-reviewed]
Japanese, Scientific journal

Optimal design of smart carriage arm in magnetic disk drive for vibration suppression
F Ohashi, Kajiwara, I., M Iwadare, T Arisaka
MICROSYSTEM TECHNOLOGIES-MICRO-AND NANOSYSTEMS-INFORMATION STORAGE AND PROCESSING SYSTEMS, 11, 8-10, 711, 717, SPRINGER, Aug. 2005
English, Scientific journal, In hard disk drives, vibration suppression is very important to boost the performance of information-processing equipment. It has been expected that technology of smart structure will contribute to the development of small and light-weight mechatronics devices with the required performance. The smart structure is composed of the piezoelectric film sensor and actuator in order to reduce the structural vibration. The placement of the piezoelectric actuator and H-2 control system are simultaneously optimized based on genetic algorithm to improve the effect on the vibration suppression. It has been verified by some applications with a plate structure and a magnetic disk drive that an enhanced performance for the vibration suppression can be achieved by the proposed optimal design method.

Efficiency of Air Injection on Stability and Emission Controls in Premixed Combustion　　　　　　　　　　　　　　　
Sato, H, Nishidome, C, Kajiwara, I, Nakajima, M, Nagao, T, Hayashi K, Ogawa, S
Proceedings of 20th International Colloquium on the Dynamics of Explosions and Reactive Systems, 73, 2005, [Peer-reviewed]
English, International conference proceedings

Multidisciplinary Design Optimization of Smart Structures for Vibration and Sound Suppression　　　　　　　　　　　　　　　
Kajiwara, I, Ono, K, Ishizuka, S
Proceedings of 11th Asia-Pacific Vibration Conference, 1, 198, 203, 2005, [Peer-reviewed]
English, International conference proceedings

Suppression of combustion noise and combustion oscillation by thermo-acoustic active control using secondary flame
Masaru Ikame, Takeyuki Kishi, Kazuyoshi Harumi, Katsuhide Hiraoka, Hideyuki Oka, Hiroyuki Sato, A. Koichi Hayashi, Chiaki Nishidome, Itsuro Kajiwara, Satoru Ogawa
Proceedings of the ASME Turbo Expo 2005, Vol 1, GT2005-68233, 549, 559, AMER SOC MECHANICAL ENGINEERS, 2005, [Peer-reviewed]
English, International conference proceedings, A feedback combustion control system based on the active noise control (ANC) principle was investigated with an experimental lean premixed dump combustor. In the control system, secondary diffusion flames were used as the sound source to attenuate pressure fluctuation in the combustion system. Piezo-valves with fast response were used to modulate the flow rate of the fuel for the secondary flames and to generate controlled sound by heat release oscillation. We investigated two kinds of controllers, that is, a time delay type controller and a model-based type one. In the experiment of the former, the dominant resonant mode of the combustion noise was suppressed more than 10dB in maximum. Clear periodicity of the suppression effect according to delay time indicates that the suppression is due to the acoustic interaction between the main flame and the secondary flames. In the model-based controller, robust control algorithms (mixed H-2/H-infinity) were used. In addition, the gain-scheduled control was implemented to tune in to the shift of the dominant mode of the combustion noise, which resulted from variation of equivalence ratio. This control system effectively suppressed the dominant mode by more than 25dB without increase in other modes.

Development of laser propulsion and tracking system for laser-driven micro-airplane
H Ishikawa, Kajiwara, I, K Hoshino, T Yabe, S Uchida, Y Shimane
BEAMED ENERGY PROPULSION, 702, 342, 353, AMER INST PHYSICS, 2004, [Peer-reviewed]
English, International conference proceedings, The purposes of this paper are to improve the control performance of the developed laser tracking system and to develop an integrated laser propulsion/tracking system for realizing a continuous flight and control of the micro-airplane. The laser propulsion is significantly effective to achieve the miniaturization and lightening of the micro-airplane. The laser-driven micro-airplane has been studied with a paper-craft airplane and YAG laser, resulting in a successful glide of the airplane. In the next stage of the laser-driven micro-airplane development, the laser tracking is expected as key technologies to achieve continuous propulsion. Furthermore, the laser propulsion system should be combined with the laser tracking system to supply continuous propulsion. Experiments are carried out to evaluate the performance of the developed laser tracking system and integrated laser propulsion/tracking system.

Integrated Design of Mechanism and Control System for Smart Structures　　　　　　　　　　　　　　　
Kajiwara, I, Ohashi, F
Proceedings of The First International Symposium on Intelligent Artifacts and Bio-systems, OS-8-4, 2004, [Peer-reviewed]
English, International conference proceedings

Multidisciplinary Optimization of Smart Structure with Characteristic Variation for Vibration Suppression　　　　　　　　　　　　　　　
Kajiwara, I., Tsuchiya, R
Proceedings of the International Workshop on Smart Materials and Structural Systems, 8, 04-1, 276, 277, 2004, [Peer-reviewed]
English, International conference proceedings

Multidisciplinary Design of Actuator Array and Adaptive Control System for Smart Structures　　　　　　　　　　　　　　　
Kajiwara, I, Tsuchiya, R
Proceedings of The Fourth International Symposium on Advanced Fluid Information and The First International Symposium Transdisciplinary Fluid Integration, IFS-TM016, 307, 312, 2004, [Peer-reviewed]
English, International conference proceedings

Integrated Laser Propulsion/Tracking System for Laser-Driven Micro-Airplane
Itsuro Kajiwara, Kentaro Hoshino, Hiroyasu Ishikawa, Yoshichika Shimane, Takashi Yabe, Shigeaki Uchida
Theoretical and Applied Mechanics Japan, 53, 115, 124, 2004, [Peer-reviewed]
English, Scientific journal, The purpose of this paper is to develop a laser tracking system and an integrated laser propulsion/tracking system for realizing a continuous flight and control of a laser-driven micro-airplane. The laser propulsion is significantly effective to achieve the miniaturization and lightening of the micro-airplane. The laser-driven micro-airplane has been studied with a paper-craft airplane and yag laser, resulting in a successful glide of the airplane. It is required that the irradiated laser is tracked to the moving micro-airplane with the laser tracking system. Furthermore, the laser propulsion system has to be combined with the laser tracking system to supply repetitive propulsion. Fundamental experiments are carried out to evaluate the performance of the developed laser tracking and laser propulsion/tracking systems. © 2004, National Committee for IUTAM. All rights reserved.

Tracking control for laser-driven micro-airplane
Hoshino K, Kajiwara, I., Hara S, Ishikawa H, Shiokata D
Proceedings of the IEEE International Conference on Control Applications, 1, 1, 6, 2004, [Peer-reviewed]
English, International conference proceedings

Integrated actuator/control design of smart pantograph mechanism for vibration suppression
Iwadare M, Kajiwara I, Tsuchiya R, Horie M
Proceedings of the IEEE International Conference on Control Applications, 2, 1717, 1722, 2004, [Peer-reviewed]
English, International conference proceedings

Laser-driven vehicles - from inner-space to outer-space
T Yabe, C Phipps, K Aoki, M Yamaguchi, R Nakagawa, C Baasandash, Y Ogata, M Shiho, G Inoue, M Onda, K Horioka, Kajiwara, I, K Yoshida
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING, 77, 2, 243, 249, SPRINGER-VERLAG, Jul. 2003, [Peer-reviewed]
English, Scientific journal, Laser-supported propulsion of a micro-airplane with a water-covered ablator is demonstrated. The repetitive use of an overlay structure is experimentally demonstrated with a specially designed water supply. Various transparent overlays are investigated by the CIP-based hydrodynamic code and by experiments using a pendulum and using a semi-conductor load cell. A momentum-coupling efficiency of similar to10(4) N s/MJ is achieved by water-exotic-target experiments, in agreement with the simulation code, which predicts a maximum efficiency of similar to10(5) N s/MJ. The concept of laser-supported propulsion can also be used for driving a Mach 5 airplane in the stratosphere, a micro-ship inside the human body, and a robot in a nuclear power reactor accident, during which large numbers of neutrons make electronic devices useless.

Motion and vibration control of flexible-link mechanism with smart structure
C Nishidome, Kajiwara, I
JSME INTERNATIONAL JOURNAL SERIES C-MECHANICAL SYSTEMS MACHINE ELEMENTS AND MANUFACTURING, 46, 2, 565, 571, JAPAN SOC MECHANICAL ENGINEERS, Jun. 2003, [Peer-reviewed]
English, Scientific journal, This study is concerned with the motion and vibration control strategy for a flexible-link mechanism composed of smart structures in order to achieve the high performance and stability. Reducing vibration and making positioning time faster are simultaneously required in this system. Technology of smart structures is introduced in the flexible-link system to achieve the vibration reduction. The smart flexible-link is composed of the flexible-link and the piezoelectric film which has the sensor/actuator functions for itself, and so its mechanism is extremely suitable for controlling the vibration. Modeling and control strategy are presented to enhance the motion and vibration control performance.

Control of wing for micro-airplane with smart material and laser
Kajiwara, I, H Ishikawa, S Furuya, T Yabe, C Nishidome
BEAMED ENERGY PROPULSION, 664, 545, 556, AMER INST PHYSICS, 2003, [Peer-reviewed]
English, International conference proceedings, A laser tracking system and a smart wing are proposed and developed to control the flight of a laser-driven micro-airplane. The laser tracking system is composed of a light source, detector and optical system with a galvano-mirror control mechanism, and used for controlling the smart wing constituted by a wing, phototransistor, battery and smart material. The light source is installed on the ground and so this system is effective for miniaturization and lightening of the micro-airplane. Experiments are carried out to evaluate the performance of the laser tracking system and the smart wing.

Optimization of Smart Structure For Realizing High Controllability　　　　　　　　　　　　　　　
Omori, T, Kajiwara, I.
Proceedings of the 2003 JSME-IIP/ASME-ISPS Joint Conference on Micromechatronics for Information and Precision Equipment, 03-208, 183, 184, 2003, [Peer-reviewed]
English, International conference proceedings

Optimal Design of Smart Carriage Arm in Magnetic Disk Drive for Vibration Suppression
Ohashi, F, Kajiwara, I, Iwadare, M, Arisaka, T
Proceedings of the 2003 JSME-IIP/ASME-ISPS Joint Conference on Micromechatronics for Information and Precision Equipment, 03-208, 181, 182, 2003, [Peer-reviewed]
English, International conference proceedings

Simultaneous design of piezoelectric shape and control system for smart structures (shape optimization of multiple piezoelectric actuators)
Kajiwara I, Uehara M
Transactions of the Japan Society of Mechanical Engineers Series C, 69, 684, 2093, 2100, The Japan Society of Mechanical Engineers, 2003, [Peer-reviewed]
Japanese, Scientific journal, A smart structure is composed of the piezoelectric film sensor and actuator in order to reduce the structural vibration. H_2 controller is designed with the reduced order model of the smart structure which is obtained by finite element and modal analyses. The control force is applied by the piezoelectric film actuator and the feedback signals are detected by the piezoelectric film sensor and the accelerometer in the system. The vibration response is suppressed by the modal control and the displacement control in which the modal coordinate displacement and the spatial displacement are taken as the controlled variable. The shapes of the multiple piezoelectric actuators and the H_2 control system are simultaneously optimized to achieve an enhanced vibration control performance. Efficient optimization algorithm based on a two-step procedure is employed in the simultaneous optimization. It is verified that an enhanced performance on vibration suppression can be achieved by the presented optimal design.

Hybrid control of motion and vibration for smart flexible-link mechanism
Nishidome C, Kajiwara, I., Nagamatsu A
Transactions of the Japan Society of Mechanical Engineers Series C, 69, 677, 10, 17, The Japan Society of Mechanical Engineers, 2003, [Peer-reviewed]
Japanese, Scientific journal, This study is concerned with the motion and vibration control strategy for a flexible-link mechanism in order to achieve high performance and stability. Reducing vibration and making positioning time faster are simultaneously required in this system. Technology of smart structures is introduced in the flexible-link system to conduct the vibration control. The smart flexible-link is composed of the two flexible-links and the piezoelectric films which have the sensor/actuator function for itself, and so its mechanism is extremely suitable for controlling the vibration. First, a modeling method of the flexible multibody systems is presented based on a functional modeling method and modal analysis. An approach for hybrid control of motion and vibration is proposed, in which a large magnitude and slow vibration is controlled by the servomotors and a minute vibration is controlled by the piezoelectric films. The motion and vibration controller for the servomotors is designed with the mixed H_2/H_∞ control problem and the vibration controller for the piezoelectric films is constructed by a direct velocity feedback, resulting in the enhanced performance on the motion and vibration control.

Microairplane propelled by laser driven exotic target
T Yabe, C Phipps, M Yamaguchi, R Nakagawa, K Aoki, H Mine, Y Ogata, C Baasandash, M Nakagawa, E Fujiwara, K Yoshida, A Nishiguchi, Kajiwara, I
APPLIED PHYSICS LETTERS, 80, 23, 4318, 4320, AMER INST PHYSICS, Jun. 2002, [Peer-reviewed]
English, Scientific journal, We propose a propulsion concept to drive a microairplane by laser that can be used for observation of climate and volcanic eruption. Since it does not have to develop thrust for vertical takeoff, and it has no engine in the normal sense, the microairplane can be very light, with its payload consisting only of observation and communication equipment. In order to demonstrate the concept, we succeeded in flying a paper microairplane driven by a 590 mJ, 5 ns pulse yttrium-aluminum-garnet laser that impinges on a double-layer "exotic target." The coupling efficiency agrees well with simulations and with experiments. (C) 2002 American Institute of Physics.

Position and Force Control of 2-Link Manipulator Using Mixed H2/H-infinity Control　　　　　　　　　　　　　　　
Kajiwara, I, Yambe, K, Nishidome, C
Proceedings of the First Asian Conference on Multibody Dynamics, 02-202, 41, 48, 2002, [Peer-reviewed]
English, International conference proceedings

Motion and Vibration Control of Flexible-Link Mechanism with Smart Structure　　　　　　　　　　　　　　　
Nishidome, C, Kajiwara, I
Proceedings of the First Asian Conference on Multibody Dynamics, 02-202, 49, 56, 2002, [Peer-reviewed]
English, International conference proceedings

Hybrid control of motion and vibration for smart flexible-link mechanism
C Nishidome, Kajiwara, I
SICE 2002: PROCEEDINGS OF THE 41ST SICE ANNUAL CONFERENCE, VOLS 1-5, 1129, 1134, IEEE, 2002, [Peer-reviewed]
English, International conference proceedings, Technology of smart structures is introduced in the flexible-link system to conduct the vibration control. The smart flexible-link is composed of the two flexible-links and the piezoelectric films which. have the sensor/actuator function for itself An approach for hybrid control of motion and vibration is proposed. in which a large magnitude and slow vibration is controlled by the servomotors and a minute vibration is controlled by the piezoelectric film actuators, The motion and vibration controller for the servomotor is designed with the mixed H-2/H-infinity control problem and the vibration controller for the piezoelectric films is constructed by a direct velocity feedback, resulting in the enhanced performance on the motion and vibration control.

Simultaneous design of mechanism and control system for smart structures (Optimization of piezoelectric placement and application to magnetic disk drive)
F Ohashi, Kajiwara, I., T Omori, T Arisaka
SICE 2002: PROCEEDINGS OF THE 41ST SICE ANNUAL CONFERENCE, VOLS 1-5, 1117, 1122, IEEE, 2002, [Peer-reviewed]
English, International conference proceedings, The placement of the piezoelectric actuator and the H. control system in a smart structure are simultaneously optimized by genetic algorithm is achieve an enhanced vibration control performance. Efficient optimization algorithm based on a two-step procedure is employed in the simultaneous optimization. in which the optimal piezoelectric placement and state feedback controller are obtained by genetic algorilhm at the 1st-step and then the dynamic compensator for the output feedback is reconstructed at the 2nd-step of the optimization. It is verified by sonic applications with a plate structure and a magnetic disk. drive that an enhanced performance for the vibration suppression can be achieved by the presented optimal design.

Design of shape and control system for micro-airplane development
H Ishikawa, Kajiwara, I, T Yabe
SICE 2002: PROCEEDINGS OF THE 41ST SICE ANNUAL CONFERENCE, VOLS 1-5, 599, 604, IEEE, 2002, [Peer-reviewed]
English, International conference proceedings, In the field of airplane, technology for higher performance, miniaturization and lightening has been attracting the attention of the aircraft engineers. But the characteristic, interference between the aerodynamics based on the structure shape and the control system can't be ignored when The miniaturization is conducted.. This paper demonstrates a design strategy of micro-airplanes by the use of simultaneous aerodynamic shape and control system optimization.

Simultaneous Optimal Design of Piezoelectric Shape/Placement and Control System for Smart Structures
Itsuro Kajiwara, Manabu Uehara, Takahiro Omori, Fumitake Ohashi
Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, 68, 674, 2925, 2932, 2002, [Peer-reviewed]
English, Scientific journal, A smart structure is composed of the piezoelectric film sensor and actuator in order to reduce the structural vibration. H2 controller is designed with the reduced order model of the smart structure which is obtained by finite element and modal analyses. The control force is applied by the piezoelectric film actuator and the feedback signals are detected by the piezoelectric film sensor and the accelerometer in the system. The vibration response is suppressed by the displacement control and the modal control in which the spatial displacement and the modal coordinate displacement are taken as the controlled variable. The shape/placement of the piezoelectric actuator and the H2 control system are simultaneously optimized to achieve an enhanced vibration control performance. Efficient optimization algorithm based on a two-step procedure is employed in the simultaneous optimization. It is verified by some applications that the enhanced performance for the vibration suppression can be achieved by the presented optimal design. © 2002, The Japan Society of Mechanical Engineers. All rights reserved.

Laser-driven vehicles - from inner-space to outer-space
T Yabe, C Phipps, K Aoki, M Yamaguchi, Y Ogata, M Shiho, G Inoue, M Onda, K Horioka, Kajiwara, I., K Yoshida
HIGH-POWER LASER ABLATION IV, PTS 1 AND 2, 4760, II, 867, 878, SPIE-INT SOC OPTICAL ENGINEERING, 2002, [Peer-reviewed]
English, International conference proceedings, Laser supported propulsion of a micro-airplane with water-covered ablator is demonstrated. The repetitive use of overlay structure is experimentally demonstrated with specially-designed water supply. The various transparent overlay is investigated by the CIP-based hydrodynamic code and experiments by pendulum and semi-conductor load cell. The momentum coupling efficiency of 5000 N-sec/MJ has been achieved by ORION experiments that agree with the simulation code. With the maximum efficiency similar to105 N-sec/MJ predicted by the simulation, 30 pulses of MJ laser can give the sound speed to 10 tons airplane. The concept can also be used for driving a micro-ship inside human body and a robot under the accidental circumstance of nuclear power reactor in which large amount of neutron source makes electronic device useless.

Proposal and Demonstration of Laser-Driven Micro-Airplane　　　　　　　　　　　　　　　
Yabe, T. Phipps, C. Aoki, K. Yamaguchi, M. Nakagawa, R. Mine, H. Ogata, Y. Baasandash, C. Nakagawa, M. Fujiwara, E. Yoshida, Kajiwara, I
Journal of Plasma and Fusion Research, 77, 12, 1177, 1179, 2001
Japanese, Scientific journal

Motion and Vibration Control of Flexible-Link Mechanism with Smart Structure
Itsuro Kajiwara, Chiaki Nishidome, Norihito Sakakibara, Manabu Uehara, Akio Nagamatsu
Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, 67, 659, 2173, 2180, 2001
English, Scientific journal, This study is concerned with the motion and vibration control strategy for the flexible-link mechanism in order to achieve the high performance and stability. Reducing vibration and making positioning time faster are simultaneously required in this system. Technology of smart structures is introduced in the flexible-link system to achieve the vibration reduction. The smart flexible-link is composed of the flexible-link and the piezoelectric film which has the sensor/actuator function for itself, and so its mechanism is extremely suitable for controlling the vibration. First, a modeling method of the flexible multibody systems is presented based on modal analysis considering the characteristics of the piezoelectric film. In this method, each flexible body modeled by FEM is transformed into the modal space at the 1st stage of the model reduction and then the total system is constructed by synthesizing each modal model and reducing it into the modal space at the 2nd stage reduction. The control system is constructed with the designed dynamic compensator based on the mixed H2/H∞ control problem resulting in the enhanced performance and stability. © 2001, The Japan Society of Mechanical Engineers. All rights reserved.

A control method for non-linear time-varying system using mixed H2/H-infinity control: Position and force control of 2-link manipulator
Kajiwara, I., Yambe, K, Nishidome, C
Proceedings of the ASME Design Engineering Technical Conference, VIB-21326, 2001, [Peer-reviewed]
English, International conference proceedings, Dynamics of multi-link manipulators are highly nonlinear and depend on the time varying configuration. This paper presents a method of gain scheduling which consists in designing a linear time invariant (LTI) controller for each operating point and in switching controller when the operating conditions change. Each LTI controller is designed based on LMI approach in which an optimization problem is defined as a mixed H 2 /H ∞ control problem with pole placement. The performance of the force and the position controls is defined by the H 2 norm, and the robust stability according to gain scheduling is evaluated with the H ∞ norm and the pole placement of the closed-loop system. The effectiveness and the practicability of the proposed method are verified by both simulations and experiments with 2-link manipulator system.

Design of shape and control system for smart structures with piezoelectric films
Kajiwara I, Uehara M
Proceedings of 19th AIAA Applied Aerodynamics Conference, 2001-1555, 2001, [Peer-reviewed]
English, International conference proceedings

Integrated design of aerodynamics and control system for Micro Air Vehicles
Kajiwara, I, RT Haftka
JSME INTERNATIONAL JOURNAL SERIES C-MECHANICAL SYSTEMS MACHINE ELEMENTS AND MANUFACTURING, 43, 3, 684, 690, JAPAN SOC MECHANICAL ENGINEERS, Sep. 2000, [Peer-reviewed]
English, Scientific journal, Technology on Micro Air Vehicles (MAVs) has been attracting the attention for aircraft's researchers. Multidisciplinary optimization is expected to achieve the higher performances and the stability for MAVs. This paper proposes the simultaneous optimization methods of the aerodynamics based on the aircraft shape and the control system. The purpose of the optimization is to reduce the control energy and the roll angle under the constraints with respect to the robust stability. The control system is composed of the H-2 and the mixed H-2/H-infinity controllers. Efficient optimization procedures based on a two step procedure for the H-2 optimization and LMI solver for the H-2/H-infinity, control are developed in this study. Both aircraft shape and control design variables are simultaneously optimized by the proposed methods. Effectiveness of the proposed approaches is verified with some numerical applications.

Motion and Vibration Control in Smart Flexible Link Mechanism　　　　　　　　　　　　　　　
Kajiwara, I. Nishidome, C. Sakakibara, N
Proceedings of International Symposium on Robotics and Automation 2000, 250, 255, 2000, [Peer-reviewed]
English, International conference proceedings

Integrated design of aerodynamics and control system for micro air vehicles
Itsuro Kajiwara, Raphael T. Haftka
JSME International Journal, Series C: Mechanical Systems, Machine Elements and Manufacturing, 43, 3, 684, 690, JSME, 2000, [Peer-reviewed]
English, Scientific journal, Technology on Micro Air Vehicles (MAVs) has been attracting the attention for aircraft's researchers. Multidisciplinary optimization is expected to achieve the higher performances and the stability for MAVs. This paper proposes the simultaneous optimization methods of the aerodynamics based on the aircraft shape and the control system. The purpose of the optimization is to reduce the control energy and the roll angle under the constraints with respect to the robust stability. The control system is composed of the H2 and the mixed H2/H∞ controllers. Efficient optimization procedures based on a two step procedure for the H2 optimization and LMI solver for the H2/H∞ control are developed in this study. Both aircraft shape and control design variables are simultaneously optimized by the proposed methods. Effectiveness of the proposed approaches is verified with some numerical applications.

Optimization for vibration problems: Junction layout of a combined structure under oscillation
Y Kawabe, S Yoshida, S Saegusa, Kajiwara, I, A Nagamatsu
JOURNAL OF MECHANICAL DESIGN, 121, 2, 188, 194, ASME-AMER SOC MECHANICAL ENG, Jun. 1999, [Peer-reviewed]
English, Scientific journal, We proposed a method for optimizing the layout of junctions between two structures so as to minimize the relative displacement between them when one of them is oscillated by noise disturbances. Layout optimization yields the minimum number of junctions, which means fewer joint components or fewer spot-welding operations leading to higher production efficiency.

Feedback Active Noise Control with Multiple Control Sources based on Modal Analysis
Hiroshi Shimojima, Yoshihiro Matsunaga, Sekiya Koike, Itsuro Kajiwara
Transactions of the Japan Society of Mechanical Engineers Series C, 65, 633, 1849, 1856, The Japan Society of Mechanical Engineers, Jan. 1999, [Peer-reviewed]
Japanese, Scientific journal, An approach for feedback active noise control of a one dimensional duct with multiple control sources based on modal analysis is presented in this paper. Based on experimental modal analysis, the modal parameters of an acoustical system are derived from measured multiple frequency response functions. The state equation of the duct is described by the identified modal parameters. Considering eigenvectors of the acoustical system calculated by finite element method, control sources are located to the duct. A feedback active noise controller is designed based on mixed H 2 /H ∞ problem in addition to H ∞ problem, preventing the increase in dimensions of the controllers. Simulations are carried out using the designed controllers. Moreover experiments are carried out using identified controllers based on modal analysis to reduce dimensions of the controllers. The desired performances are obtained by the presented approach. © 1999, The Japan Society of Mechanical Engineers. All rights reserved.

Structural dynamic design considering controllability and stability
Kajiwara I, Nagamatsu A
Proceedings of the IEEE International Conference on Systems, Man and Cybernetics, 3, 152, 157, 1999, [Peer-reviewed]
English, International conference proceedings

Integrated design of structure and control system considering performance and stability
Kajiwara Itsuro, Nagamatsu Akio
Proceedings of IEEE Conference on Control Applications, 86, 91, 1999, [Peer-reviewed]
English, International conference proceedings

Simultaneous optimum design of shape and control system for micro air vehicles
Kajiwara Itsuro, Haftka Raphael T
Proceedings of 40th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, AIAA-1999-1391, 1612, 1621, 1999, [Peer-reviewed]
English, International conference proceedings

Robust identification and control design for truck cab model device
ZY Guo, Kajiwara, I, A Nagamatsu
JSME INTERNATIONAL JOURNAL SERIES C-MECHANICAL SYSTEMS MACHINE ELEMENTS AND MANUFACTURING, 41, 2, 171, 177, JAPAN SOC MECHANICAL ENGINEERS, Jun. 1998, [Peer-reviewed]
English, Scientific journal, The increasing attention on the applications of advanced robust control theories to automotive motivates the further investigation of truck cab model device for active vibration control. A balanced state-space model is necessary when designing a robust controller. Hence, the state-space frequency domain identification method is used to construct a model for model-based robust control design. Then H-infinity control theory and mu synthesis are readily to be used in order to calculate a controller for vibration suppression. The nu-tool is exploited to evaluate the quantitative margin for robust stability and performance. Finally, the closed-loop system achieved the satisfactory control results.

H∞ Control Design of Experimental State-Space Modeling for Vehicle Vibration Suppression　　　　　　　　　　　　　　　
Guo, Z., Kajiwara, I., Nagamatsu, A
SAE Transactions, 106, 6, 2812, 2817, 1998, [Peer-reviewed]
English, Scientific journal

Modeling and Active Noise Control of One Dimensional Duct Based on Modal Analysis and LMI
Itsuro Kajiwara, Masanao Fukuda, Hiroshi Shimojima
Transactions of the Japan Society of Mechanical Engineers Series C, 64, 621, 1668, 1675, The Japan Society of Mechanical Engineers, Jan. 1998, [Peer-reviewed]
Japanese, Scientific journal, Approach for modeling and feedback noise control of a one dimensional duct based on experimental modal analysis and LMI is presented in this paper. The modal parameters of a coupled acoustical structural system are derived from measured noise and vibration data. The state equation of the duct is described by the identified modal parameters. An active noise controller is designed based on LMI approach in which an optimization problem is defined as a mixed H2/H∞ control problem. The performances of the noise reduction and the robust stability are described with H2 and H∞ norms of the closed loop system, respectively. Frequency response shaping is performed by the presented approach with weighted modal matrix and frequency weighting functions. Simulations and experiments are carried out and the desired performances are obtained by the presented approach. © 1998, The Japan Society of Mechanical Engineers. All rights reserved.

A Control Method for Non-Linear Time-Varying System Using Mixed H2/H∞Control (Position and Force Control of 2–Link Manipulator)
Itsuro Kajiwara, Katsuhiro Yambe, Hiroshi Shimojima
Transactions of the Japan Society of Mechanical Engineers Series C, 64, 626, 3839, 3846, The Japan Society of Mechanical Engineers, Jan. 1998, [Peer-reviewed]
Japanese, Scientific journal, Dynamics of multi-link manipulators are highly nonlinear and depend on the time varying configuration. This paper presents a method of gain scheduling which consists in designing an linear time invariant (LTI) controller for each operating point and in switching controller when the operating conditions change. Each LTI controller is designed based on LMI approach in which an optimization problem is defined as a mixed H 2 /H ∞ control problem with pole placement. The performances of the force and the position controls are defined by the H 2 norm, and the robust stability according to gain scheduling is evaluated with the H ∞ norm and the pole placement of the closed-loop system. The effectiveness and the practicability of the proposed method are verified by both simulations and experiments with 2-link manipulator system. © 1998, The Japan Society of Mechanical Engineers. All rights reserved.

Structural topology optimization by genetic algorithm (approaches for improvement of calculation efficiency)
Kajiwara Itsuro, Nagamatsu Akio
Proceedings of the International Conference on Inverse Problems in Engineering, 253, 260, 1998, [Peer-reviewed]
English, International conference proceedings

Integration of experimental state-space modeling based on ERA and H-infinity control design
Kajiwara, I., ZY Guo, A Nagamatsu
JSME INTERNATIONAL JOURNAL SERIES C-MECHANICAL SYSTEMS MACHINE ELEMENTS AND MANUFACTURING, 40, 2, 197, 202, JAPAN SOC MECHANICAL ENGINEERS, Jun. 1997, [Peer-reviewed]
English, Scientific journal, State-space solutions of the H infinity controller are well developed. Hence, for real structure control design, the first step is to derive a state-space model of the structure. There are several analytical and experimental dynamic modeling methods that can be used. It is difficult to obtain an accurate model for a flexible and complex structure by the finite-element method (FEM). Therefore experimental modeling is attempted. In this work, we used the eigensystem realization algorithm (ERA) time-domain method based on system impulse response data, to establish a state-space model in order to design the H infinity control law for vibration suppression. The robust control implementation is exerted on a test bed (truck cab model) with three degrees of freedom. The validity of experimental state-space modeling is confirmed and the robust control performance is achieved.

Integration of experimental state-space modeling based on ERA and H-infinity control design
Kajiwara, I, ZY Guo, A Nagamatsu
JSME INTERNATIONAL JOURNAL SERIES C-MECHANICAL SYSTEMS MACHINE ELEMENTS AND MANUFACTURING, 40, 2, 197, 202, JAPAN SOC MECHANICAL ENGINEERS, Jun. 1997, [Peer-reviewed]
English, Scientific journal, State-space solutions of the H infinity controller are well developed. Hence, for real structure control design, the first step is to derive a state-space model of the structure. There are several analytical and experimental dynamic modeling methods that can be used. It is difficult to obtain an accurate model for a flexible and complex structure by the finite-element method (FEM). Therefore experimental modeling is attempted. In this work, we used the eigensystem realization algorithm (ERA) time-domain method based on system impulse response data, to establish a state-space model in order to design the H infinity control law for vibration suppression. The robust control implementation is exerted on a test bed (truck cab model) with three degrees of freedom. The validity of experimental state-space modeling is confirmed and the robust control performance is achieved.

Structural Topology Optimization for Dynamical Design　　　　　　　　　　　　　　　
Kajiwara, I. Nagamatsu, A. Kawabe, Y. Yoshida, S
Proceedings of JSME International Symposium on Optimization and Innovative Design, CD-ROM, #97-210, 1997, [Peer-reviewed]
English, International conference proceedings

H∞ control design of experimental state-space modeling for vehicle vibration suppression
Zhongyang Guo, Itsuro Kajiwara, Akio Nagamatsu, Tsutomu Sonehara
SAE Technical Papers, P-309, 2, 631, 637, 1997, [Peer-reviewed]
English, International conference proceedings, State-space solutions of H∞ controller have been well developed. Hence to a real structure control design, the first step is to get a state space model of the structure. There are analytical and experimental dynamic modeling methods. As we know, it is hard to obtain an accurate model for a flexible and complex structure by FEM(Finite Element Method). Then the experimental modeling methods are used. In this paper, we use frequency domain modal analysis technique based on system FRF(Frequency Response Function) data and ERA(Eigensystem Realization Algorithm) time domain method based on system impulse response data to establish state-space model in order to design H∞ control law for the purpose of vibration suppression. The robust control implementation is exerted on a testbed (truck cab model device) with three degrees of freedom. The validity of experimental state-space modeling is testified and the obvious vibration control performances are achieved. © Copyright 1997 Society of Automotive Engineers, Inc.

Robust identification and control design for engine mount
ZY Guo, H Guan, ZZ Hu, Kajiwara, I, A Nagamatsu
PROCEEDINGS OF THE 36TH IEEE CONFERENCE ON DECISION AND CONTROL, VOLS 1-5, 858, 859, IEEE, 1997, [Peer-reviewed]
English, International conference proceedings, The increasing attention on the applications of advanced robust control to automotive motivates the investigation of engine mount The state-space frequency domain identification method is used to construct a model for robust control design. Then an H infinity controller is calculated by the LMIs algorithm for the vibration suppression of engine mount.

State-space modeling, uncertainty descriptions and H∞/μ/ν control design for vibration suppression
Guo Zhongyang, Kajiwara I, Nagamatsu A
Proceedings of 38th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, AIAA-97-1399, 655, 663, 1997, [Peer-reviewed]
English, International conference proceedings

Vibration analysis in high-frequency domains based on finite-element method and modal analysis
Kajiwara Itsuro, Takahashi Naoki, Nagamatsu Akio
Transactions of the Japan Society of Mechanical Engineers Series C, 62, 599, 2556, 2562, The Japan Society of Mechanical Engineers, Jul. 1996, [Peer-reviewed]
Japanese, Scientific journal, The finite-element method (FEM) and modal analysis have been used for vibration prediction in relatively low frequency domains, and statistical energy analysis (SEA) has been conducted in order to evaluate the vibration in extremely high-frequency domains. However, modeling and vibration analysis by FEM and modal analysis become more difficult as the frequency becomes higher, and some approximations and hypotheses that have not yet been proven to be accurate are used in SEA. Therefore, in high-frequency domains that exist between the two frequency domains in which FEM and SEA can be appropriately applied, no effective vibration analysis method has been proposed. In this paper, a vibration analysis method based on modal analysis and the statistical method which enables analysis of the high-frequency vibration is presented. Example results are shown for a single-plate structure and an L-shaped structure, and a comparison is made between the results from the asymptotic modal analysis and from the experiment.

Integrated Optimum Design of Structure and Control System with LQR and H-infinity Controller　　　　　　　　　　　　　　　
Kajiwara, I, Nagamatsu, A
Proceedings of First European Conference on Structural Control, 1, 8, 1996, [Peer-reviewed]
English, International conference proceedings

H-infinity Robust Vibration Control of a Truck Cab using Modal Analysis
Sonehara, T, Kawai, K, Kubo, Y, Kajiwara, I., Nagamatsu, A.
Journal of JSAE, 27, 4, 83, 87, 自動車技術会, 1996, [Peer-reviewed]
Japanese

Concurrent Optimum Design of Structure and H∞ Control System by Genetic Algorithm　　　　　　　　　　　　　　　
Kajiwara, I. Nagamatsu, A
Proceedings of the 3rd International Conference on Motion and Vibration Control, 3, 327, 332, 1996
English, International conference proceedings

Integrated optimum design of structure and servosystem with dynamic compensator
I. Kajiwara, A. Nagamatsu, K. Seki, Y. Kotani
37th AIAA/ASME/ASCE/AHS/ASC Structure, Structural Dynamics and Materials Conference, CP962, 1005, 1015, American Institute of Aeronautics and Astronautics Inc, AIAA, 1996, [Peer-reviewed]
English, International conference proceedings, Approaches for optimum design of structure and servosystem to achieve high speed positioning and stability are developed in this paper. Both the structural optimization considering controllability and the integrated optimum design of structure and servosystem are discussed to realize the desired properties of the closed-loop system. This paper considers two types of the servosystem, namely one is composed of dynamic compensator for single input and single output system, and the other is composed of LQI control system. The desired frequency characteristics of the servosystem are achieved by the integrated optimization of structure and dynamic compensator. The integrated optimization of structure and LQI control system can improve the time history response of the closed-loop system. Furthermore, assuring the stability against the high order modes of the structure is satisfied by the integrated optimizations. Simulation and experimental results with a simplified positioning device show the effectiveness and the practicability of the proposed approaches.

Structural topology optimization by genetic algorithm (improvement of calculation efficiency for real system optimization)
Kajiwara Itsuro, Sasaki Yasutaka, Nagamatsu Akio
Transactions of the Japan Society of Mechanical Engineers Series C, 62, 597, 1731, 1738, 1996, [Peer-reviewed]
Japanese, Scientific journal

Integrated Optimum Design of Structure and H∞ Control System
Tsujioka, K, Kajiwara, I, Nagamatsu, A
AIAA Journal, 34, 1, 159, 165, AMER INST AERONAUT ASTRONAUT, 1996
English, Scientific journal, An approach for an integrated optimum design of a structure and an Hm control system is presented. The complex method and the genetic algorithm are adopted in the optimization process in the integrated design. The structural shape and the control system, including the locations of both sensors and actuators, are optimized simultaneously by the proposed approach. The improvement of frequency response shaping under the constraint of the structural mass can be realized by the integrated optimum design presented in this paper, The desired properties with respect to the control performance and the robustness are realized by the frequency shaping ability of H-infinity control. Effectiveness of the presented approach is verified by both simulation and experiment by the integrated design of a panel structure and H-infinity control system.

Simultaneous Optimum Design of the Structure and H∞ Control System.
Kazuaki Tsujioka, Itsuro Kajiwara, Akio Nagamatsu
Transaction of the Japan Society of Mechanical Engineers, 61, 583, 967, 974, 1995, [Peer-reviewed]
Japanese, Scientific journal

Integrated Optimum Design of the Structure and H∞ Control System using Genetic Algorithm
Kazuaki Tsujioka, Itsuro Kajiwara, Akio Nagamatsu
Transactions of the Japan Society of Mechanical Engineers, 61, 587, 2704, 2711, Jan. 1995, [Peer-reviewed]
Japanese, Scientific journal, An approach for integrated optimum design of a structure and H ∞ control system using a genetic algorithm is proposed. The size and shape of the structure, and the sites at which the sensors and the actuators are set are adopted as the design variables. Since the sensors and the actuators are placed only on the nodes of the finite-element model in this study, the design variables are discrete. Therefore, in order to solve this problem, a genetic algorithm is used as the optimization technique. The approach is applied to vibration control of a planar plate. A frequency weighting function and mode weighting coefficient are used in the H ∞ control problem. The mode weighting coefficient enables control of multiple natural modes without increasing the order of the controller. Effectiveness and practicability of the approach are verified by both simulation and experiment. © 1995, The Japan Society of Mechanical Engineers. All rights reserved.

Structural Shape Optimization of Vibration Characteristics
Itsuro Kajiwara, Yoshiko Kawabe, Shinobu Yoshida, Shozo Saegusa, Akio Nagamatsu
Transactions of the Japan Society of Mechanical Engineers Series C, 61, 587, 2662, 2667, The Japan Society of Mechanical Engineers, Jan. 1995, [Peer-reviewed]
Japanese, Scientific journal, A structural topology optimization technique which optimizes the frequency response characteristics is proposed in this paper. The natural frequency and the linear quadratic performance index with respect to the response are defined as the objective function. The density of each finite element is adopted as the design variable and the optimum distribution of the density is sought based on the quasi-Newton method. Minimizig the performance index against the white and the colored noise disturbances, frequency response shaping is achieved. In order to realize the actual structure, a method to separate the value of the density to zero and one, in which the penalty function to divide the density into the two values is introduced in the objective function, is also proposed. © 1995, The Japan Society of Mechanical Engineers. All rights reserved.

Structural shape optimization for improvement of dynamical characteristics
Kajiwara I, Nagamatsu A, Kawabe Y, Yoshida S, Saegusa S
Proceedings of ASME PVP Conference, 305, 279, 283, 1995, [Peer-reviewed]
English, International conference proceedings

Simultaneous optimum design of structure and control system using complex method
Tsujioka Kazuaki, Kajiwara Itsuro, Nagamatsu Akio
Proceedings of ASME Pressure Vessels and Piping Division (Publication) PVP, 305, 297, 303, 1995, [Peer-reviewed]
English, International conference proceedings

Integrated optimum design of structure and control system by modal analysis
Kajiwara I, Tsujioka K, Nagamatsu A
Proceedings of 1995 ASME Design Engineering Division (Publication) DE, 84, 3 Pt C, 487, 494, 1995, [Peer-reviewed]
English, International conference proceedings

Integrated optimum design of structure and H^∞ control system
Tsujioka K, Kajiwara, I., Nagamatsu A
Proceedings of AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, 5, 2983, 2991, 1995, [Peer-reviewed]
English, International conference proceedings

Optimum Design of Structure and Control Systems by Modal Analysis
Itsuro Kajiwara, Akio Nagamatsu
Transactions of the Japan Society of Mechanical Engineers Series C, 60, 570, 368, 373, The Japan Society of Mechanical Engineers, Jan. 1994
Japanese, Scientific journal

Approach for simultaneous optimization of a structure and control system
I. Kajiwara, K. Tsujioka, A. Nagamatsu
AIAA Journal, 32, 4, 866, 873, 1994, [Peer-reviewed]
English, Scientific journal, A new approach is presented for simultaneous structural and control optimum design of a system. The design variables of both the structural and the control parameters are optimized simultaneously by the sensitivity analysis to minimize the response due to disturbances of both white noise and colored noise subjected to a constraint so that the system is stable corresponding to high-order natural modes. Three kinds of models are adopted in this approach, namely, the original spatial model by finite element method, the reduced modal model for designing the control system, and the original modal model for assuring stability of the system. The validity and the usefulness of the present approach are verified by a vibration control experiment of a steel plate. © 1994 American Institute of Aeronautics and Astronautics, Inc., All rights reserved.

H-INFINITY CONTROL-SYSTEM BY MODAL-ANALYSIS FOR SUPPRESSION OF STRUCTURAL VIBRATION
KAJIWARA, I, A NAGAMATSU
PROCEEDINGS OF THE 12TH INTERNATIONAL MODAL ANALYSIS CONFERENCE, VOLS 1 AND 2, 2251, 591, 597, SOC EXPERIMENTAL MECHANICS INC, 1994, [Peer-reviewed]
English, International conference proceedings

OPTIMUM DESIGN OF OPTICAL PICK-UP BY ELIMINATION OF RESONANCE PEAKS
KAJIWARA, I, A NAGAMATSU
JOURNAL OF VIBRATION AND ACOUSTICS-TRANSACTIONS OF THE ASME, 115, 4, 377, 383, ASME-AMER SOC MECHANICAL ENG, Oct. 1993, [Peer-reviewed]
English, Scientific journal, A method for structural dynamic optimization is proposed using sensitivity analysis of resonance and anti-resonance frequencies. The sensitivity of the anti-resonance frequency is newly defined. An approach for eliminating the resonance peak from the frequency response function (FRF) is proposed using this sensitivity, modifying both the frequencies of this resonance and the neighboring anti-resonance bottom to the same value. The proposed method is applied to determine the optimum thickness of a plate in order to eliminate resonance peaks from its FRF. Effectiveness of this method is verified experimentally. Optimum design of an optical actuator for a compact disk player is performed practically by eliminating resonance peaks which deteriorates its servo control function. The player, with this optimized actuator, shows an excellent performance of sound playback.

Optimum Control System Design for High Degree-of-Freedom Structures　　　　　　　　　　　　　　　
Kajiwara, I, Nagamatsu, A
Proceedings of Asia-Pacific Vibration Conference ’93, 3, 929, 934, 1993, [Peer-reviewed]
English, International conference proceedings

Design of Robust Vibration Control System using Modal Analysis and H-infinity Control　　　　　　　　　　　　　　　
Kajiwara, I., Nagamatsu, A
Proceedings of Asia-Pacific Vibration Conference ’93, 3, 935, 940, 1993, [Peer-reviewed]
English, International conference proceedings

Simultaneous optimum design of structure and control system to assure stability of higher modes
Kajiwara, I., Tsujioka K, Nagamatsu A
Proceedings of AIAA/ASME Structures, Structural Dynamics and Materials Conference, pt 3, 1409, 1417, 1993, [Peer-reviewed]
English, International conference proceedings

Simaltaneous Optimum Design of Structure and Control System using Complex Method
Tsujioka, K., Kajiwara, I., Nagamatsu, A.
Transaction of the Japan Society of Mechanical Engineers, 59, 563, 2124, 2131, 1993
Japanese, Scientific journal

Simultaneous optimum design of structure and control systems by sensitivity analysis
Itsuro Kajiwara, Akio Nagamatsu
Finite Elements in Analysis and Design, 14, 2-3, 187, 195, 1993, [Peer-reviewed]
English, Scientific journal, An approach is proposed for simultaneous optimum design of a structure and feedback control system by sensitivity analysis, for the following two purposes. One is to decrease both the response and the control force of the system under a white noise disturbance force. The other is to modify the gain, the pole and the zero-point to the desirable values. The weighting constant of the feedback control system, and the mass, stiffness, shape, dimensions, etc. of the structure, are adopted simultaneously as the design variables. The proposed method is verified by a model simulation. © 1993.

Optimum design of structures by sensitivity analysis
Itsuro Kajiwara, Akio Nagamatsu
Finite Elements in Analysis and Design, 14, 2-3, 101, 110, 1993, [Peer-reviewed]
English, Scientific journal, A series of researches by the authors on structural optimum design by sensitivity analysis is introduced. First, the sensitivity of the anti-resonance frequency is defined, and an approach to eliminate the resonance peak from the frequency response function is proposed using this sensitivity. Next, an experimental approach for structural optimization based on a vibration test is introduced. An approach for optimum design combined with a substructure synthesis method is proposed, in which the objective function is an impulse response function. The proposed methods are illustrated by some examples. © 1993.

OPTIMUM DESIGN OF STRUCTURE BY SENSITIVITY ANALYSIS
KAJIWARA, I, A NAGAMATSU
PROCEEDINGS OF THE 11TH INTERNATIONAL MODAL ANALYSIS CONFERENCE, VOLS 1 AND 2, 1923, pt 2, 883, 889, SPIE - INT SOC OPTICAL ENGINEERING, 1993, [Peer-reviewed]
English, International conference proceedings

Reduced Modelling of Structure of Large Degrees-of-Freedom and Optimum Design of Its Control System
梶原逸朗, 長松昭男, 稲垣亨
Transactions of the Society of Instrument and Control Engineers, 28, 3, 383, 391, The Society of Instrument and Control Engineers, 1992, [Peer-reviewed]
Japanese, Scientific journal, The authors propose a method to design the optimum control system toward flexible structural systems. The mechanical structures used to be modelled by FEM. As a result, these models have large degrees of freedom. The small model can be obtained by identifying the spatial matrices of the structure from the frequency response functions calculated by FEM. The optimum control system is easily designed by applying the optimum control theory to the identified system. However, the stability of the control system is not always guaranteed because the machanical system is generally identified with small degree of freedom in which high order modes are ignored. An optimization method of the control system which guarantees the stability of the actual system of large degrees of freedom is proposed in this paper. The characteristics of both the identified and the actual systems are simultaneously optimized by the proposed method based on sensitivity analysis and nonlinear programming. An application to a FEM model and experimental result verify the effectiveness of the proposed method.

Optimum Design of Control System for Large Degrees-of-Freedom Structure to Assure Stability Against High Mode Vibrational Disturbance　　　　　　　　　　　　　　　
Kajiwara, I. Nagamatsu, A
Proceedings of AIAA 33rd SDM Conference, AIAA-92-2323-CP, 1595, 1603, 1992, [Peer-reviewed]
English, International conference proceedings

H∞ Robust Vibration Control of Continuous Structures using Modal Analysis
梶原逸朗, 稲垣亨, 長松昭男
Transactions of the Japan Society of Mechanical Engineers, 58, 555, 3238, 3245, The Japan Society of Mechanical Engineers, 1992, [Peer-reviewed]
Japanese, Scientific journal, In this paper, we consider a robust vibration control of a continuous body structure, such as plate structure. Modeling of a complex structure composed by a continuous body is difficult. FEM is usually used for direct modeling of an actual structure. However, FEM model has originally structural errors and FEM model has so large degree-of-freedom (DOF) that a vibration control system can hardly be designed. This model is reduced to modal coordinate in order to decrease DOF of FEM model. However, the control system becomes unstable frequently because of structural errors and ignored high order modes. We show a design method of a robust vibration control system based on H^∞ control theory. The robustness against structural errors and ignored high order modes can be realized by H^∞ control. Both the control performance and the robustness of the closed loop system can be improved by applying adequate weighting functions of H^∞ control. The effectiveness of the method is verified by the results of both analysis and experiment.

Optimum Design of Vibration Control System using Modal Analysis and Sensitivity Analysis
Itsuro Kajiwara, Tohru Inagaki, Akio Nagamatsu
Transactions of the Japan Society of Mechanical Engineers Series C, 58, 552, 2365, 2372, The Japan Society of Mechanical Engineers, Jan. 1992, [Peer-reviewed]
Japanese, Scientific journal, The authors propose a method by which to design an optimum vibration control system composed of continuous body structures using modal analysis and sensitivity analysis. The mechanical structures are modeled first by FEM. This spatial model is of such a high degree-of-freedom (DOF) that a control system cannot be designed. This spatial model is transformed into a modal model in order to reduce DOF. The optimum control system is designed by applying the optimum control theory to this reduced model. However, stability of the control system is not always guaranteed because the modal model ignores high-order modes. An optimization method of the control system which guarantees stability of the actual system is proposed in this paper. We propose also an experimental optimization of the control system based on experimental modal analysis. The optimization is performed using sensitivity analysis and nonlinear programming. The effectiveness of the proposed method is verified by both simulation and experiment. © 1992, The Japan Society of Mechanical Engineers. All rights reserved.

Modelling and Optimum Design of the Control System based on the Identification of Spatial Matrices
Itsuro Kajiwara, Akio Nagamatsu, Masaaki Okuma, Toru Inagaki
Transactions of the Japan Society of Mechanical Engineers Series C, 58, 549, 1385, 1391, Jan. 1992, [Peer-reviewed]
Japanese, Scientific journal, The authors propose a method to design the optimum control system toward flexible structural systems. The mechanical structural system can be modelled by identifying the spatial matrices from experimental frequency response functions. The optimum control system is easily designed by applying the optimum control theory to the identified system. However, the stability of the control system is not always guaranteed because the mechanical system is generally identified with small degrees of freedom ignoring high-order modes. This report proposes an optimization method of the control system which guarantees the stability of the actual system which is also an identified system with high degrees of freedom. The characteristics of both the identified and actual system are simultaneously optimized by the proposed method based on sensitivity analysis and nonlinear programming. An experimental example verifies the effectiveness of the proposed method. © 1992, The Japan Society of Mechanical Engineers. All rights reserved.

Optimum design of structure by sensitivity analysis
Kajiwara, I., Nagamatsu A
Proceedings of the 1991 Asia-Pacific Vibration Conference, 2, 61, 66, 1991, [Peer-reviewed]
English, International conference proceedings

Approach to simultaneous optimum design of structure and control systems by sensitivity analysis
Kajiwara I, Nagamatsu A
Proceedings of American Society of Mechanical Engineers, Design Engineering Division, 38, 179, 184, 1991, [Peer-reviewed]
English, International conference proceedings

An Approach of Optimal Design for Simultaneous Optimization of Structure and Control Systems using Sensitivity Analysis
梶原逸朗, 長松昭男
Transactions of The Society of Instrument and Control Engineers, 26, 10, 1140, 1147, 1990, [Peer-reviewed]
Japanese, Scientific journal

Vibration Control in a Box-Type Structure by Dual Dynamic Absorbers
Shigeo Yamashita, Itsuro Kajiwara, Kazuto Seto
Transactions of the Japan Society of Mechanical Engineers Series C, 56, 528, 2107, 2114, The Japan Society of Mechanical Engineers, Jan. 1990, [Peer-reviewed]
Japanese, Scientific journal, A polyhedron shell such as a box-type structure is used to cover a noise source and muffle emission noise. However, this structurre vibrates easily and cannot muffle noise completely, since it has low damping qualities. This paper shows that a number of resonance peaks occurring in a polyhedron shell can be suppressed by using a design method of dynamic absorbers to control the vibration of multi-degree-of-freedom systems, and this method will possibly be used to control this type of noise in the future. Four dual dynamic absorbers designed by the experimental method could control the vibration of the structure well. The effectiveness and generality of this method is confirmed by the modal analysis using the finite element method. © 1990, The Japan Society of Mechanical Engineers. All rights reserved.

A Structural Optimization Method considering Time History Response
Itsuro Kajiwara, Akio Nagamatsu
Transactions of the Japan Society of Mechanical Engineers Series C, 56, 522, 391, 397, The Japan Society of Mechanical Engineers, Jan. 1990, [Peer-reviewed]
Japanese, Scientific journal, In the typical structural optimization method, the structural eigenvalues or eigenvectors are modified in order to avoid various problems caused by the resonances. In this case, the optimization is done on frequency domain. However, in some cases the time history response is more important than the characteristics on frequency domain. In this paper, the optimizations of both natural mode and impuls reponse are performed by modifiying the thicknesses and the nodal coordinates of the structure with the FEM model. Firstly, the theory of the optimization method is explained. Secondly, we apply this method to the optimization of an rectangular plate. The optimization of a natural mode and a impuls response are achieved. Finally, we combine this method with the component mode synthesis method in order to enable us to optimize the large structural systems. © 1990, The Japan Society of Mechanical Engineers. All rights reserved.

Design of an Optical Servosystem Using a Structural Optimizing Method Considering Controllability (3rd Report, An Application of the Pole-Zero Cancellation Method to Development of Optical Pick-Up)
Itsuro Kajiwara, Kazuto Seto, Akio Nagamatsu, Hiroaki Morifuji, Nobuyuki Nakae
Transactions of the Japan Society of Mechanical Engineers Series C, 55, 516, 2045, 2052, The Japan Society of Mechanical Engineers, Jan. 1989, [Peer-reviewed]
Japanese, Scientific journal, The design method of an optical servosystem and its practicability were discussed in the first and second reports. In this paper, the authors develop a practical optical pick-up. Firstly, we propose a new type of optical pick-up which is a simple monobloc hinge-type structure and investigate its structural characteristics. As a result, it is confirmed that the structural characteristics of the optical pick-up influence the stability of the servosystem ; accordingly, a structural optimization is necessary to obtain a high degree of controllability. Secondly, the optical pick-up is optimized by using the Pole-Zero Cancellation Method and the servosystem is comprised of the optimal pick-up with the phase-lead compensator. The results of both analytical and experimental investigations verify that the servo characteristics are improved and sufficient characterisitics are satisfied such that the servo specifications are realized. © 1989, The Japan Society of Mechanical Engineers. All rights reserved.

Design of an Optical Servosystem using a Structural Optimizing Method considering Controllability (1st Report, A Total Design combining a Structural System with a Control System by way of Vibration Nodes)
Kazuto Seto, Itsuro Kajiwara, Akio Nagamatsu, Hiroaki Morifuji
Transactions of the Japan Society of Mechanical Engineers Series C, 55, 516, 2029, 2036, The Japan Society of Mechanical Engineers, Jan. 1989, [Peer-reviewed]
Japanese, Scientific journal, This paper proposes a new design concept that takes into consideration the construction of a mechanism that consists of a structural system and a control system. In order to obtain a fine mechanism with high performance, it is necessary to prepare the structural system with higher controllability in the design stage. The essence of the concept is to make practical lse of the nodes at the vibration modes of the structural system for the purpose of suitably arranging the controller and the sensor within it. Firstly, uncontrollability and unobservability, which correspond to the pole-zero cancellation, is realized on the vibration node. Next, it is shown that the controller located on the vibration node cancels any undesirable resonance peak of the structural system required for achieving higher controllability. The effectiveness of the design concept is demonstrated by the design of the optical servosystem. © 1989, The Japan Society of Mechanical Engineers. All rights reserved.

Design of an Optical Servosystem Using a Structural Optimizing Method Considering Controllability (2nd Report, the Structural Optimization of an Optical Pick-Up Model Using the Pole-Zero Cancellation Method)
Itsuro Kajiwara, Kazuto Seto, Akio Nagamatsu
Transactions of the Japan Society of Mechanical Engineers Series C, 55, 516, 2037, 2044, The Japan Society of Mechanical Engineers, Jan. 1989, [Peer-reviewed]
Japanese, Scientific journal, The optical servosystem requires a high degree of controllability. However, it is very difficult to realize a servosystem with higher controllability since the dynamic characteristics of an optical pick-up influence the stability of the servosystem. Therefore, both a control system and a structural system must be considered simultaneously in the design stage of the optical servosystem. The purpose of this paper is to determine the structural system in order to obtain higher controllability. Firstly, the authors investigate the structural characteristics of an optical pick-up model and explain the necessity of structural optimization to improve servo characteristics. Secondly, the structure of the optical pick-up model is optimized by using the Pole-Zero Cancellation Method proposed by the authors. The servosystem is comprised of the optical pick-up model with the phase-lead compensator. Finally, the characteristics of the servosystem are investigated and the improvements are confirmed. The practicability of this design method is verified by the experiments. © 1989, The Japan Society of Mechanical Engineers. All rights reserved.

Technique of structural dynamic optimization using sensivities of resonance and anti-resonance frequencies
Kajiwara I, Agamatsu A, Seto K
Proceedings of ASME PVP Conference, 179, 161, 167, 1989, [Peer-reviewed]
English, International conference proceedings

A Technique of Structural Dynamic Optimization using Resonance and Anti-Resonance Sensitivities
Itsuro Kajiwara, Masaaki Ookuma, Akio Nagamatsu, Kazuto Seto
Transactions of the Japan Society of Mechanical Engineers Series C, 54, 505, 2084, 2091, The Japan Society of Mechanical Engineers, Jan. 1988, [Peer-reviewed]
Japanese, Scientific journal, In this report, the authors propose a new method for structural dynamic modification. The resonance sensitivity and anti-resonance sensitivity of a structure are used in the proposed method. Both sensitivities can be calculated much more easily than the sensitivity for the natural modes because of the simplicity of the calculational procedure. Therefore, this method has a high degree of efficiency. The target peaks of resonance are removed by making the vibration node coincide with an exciting point. As a result, cancel of the resonance peaks is achieved. In this paper, the theory of the proposed method is explained at first. Secondly, the effectiveness of this method is concretely shown with two applications: a 6-degrees-of-freedom system and a rectangular plate. In the latter application, an experiment is also performed in order to verify the effectiveness and accuracy of the method. © 1988, The Japan Society of Mechanical Engineers. All rights reserved.

青果物の非接触非破壊品質評価システム
細矢直基, 梶原逸朗, 芝浦工業大学特別教育・研究報告集(CD-ROM), 2016, 288‐291, 31 Jul. 2017
Japanese

青果物の非接触非破壊品質評価システム
細矢直基, 梶原逸朗, 芝浦工業大学特別教育・研究報告集(CD-ROM), 2015, 284‐287, 287, 30 Sep. 2016
芝浦工業大学連携推進部, Japanese

レーザ誘起プラズマによるモーメント加振法
細矢直基, 梶原逸朗, 芝浦工業大学特別教育・研究報告集(CD-ROM), 2014, 247, 250, 30 Jun. 2015
芝浦工業大学連携推進部, Japanese

レーザーブレイクダウンプラズマによる衝撃波を用いた微小空間のための音響加振法
細矢直基, 梶原逸朗, 芝浦工業大学特別教育・研究報告集(CD-ROM), 2012, 136, 139, 28 Jun. 2013
Japanese

スマート構造による振動／騒音の制御技術　　　　　　　　　　　　　　　
梶原 逸朗, 日本機械学会D&D2010・夏の学校「能動制御／騒音制御の基礎」テキスト, 25, 34, 2012
Japanese, Introduction scientific journal

振動の抑制・アクティブ制御　　　　　　　　　　　　　　　
梶原 逸朗, 日本機械学会関西支部・第320回講習会「実務者のための振動基礎と制振・制御技術」, 51, 76, 2012
Japanese, Introduction scientific journal

レーザー加振に基づくヘルスモニタリング
細矢直基, 梶原逸朗, 芝浦工業大学特別教育・研究報告集(CD-ROM), 2010, 112, 115, 01 Dec. 2011
Japanese

13・5 最適化(13.機械力学・計測制御,<特集>機械工学年鑑)
梶原 逸朗, 日本機械学會誌, 111, 1077, 686, 687, 05 Aug. 2008
一般社団法人日本機械学会, Japanese

振動の制御技術　　　　　　　　　　　　　　　
梶原逸朗, 日本機械学会講習会「振動解析入門－振動の基礎から実験モード解析，CAE解析まで－」テキスト, 06-80, 53, 61, 2006

スマート構造における構造と制御の複合領域最適化
梶原逸朗, 機械の研究, 58, 9, 937, 944, 2006
養賢堂, Japanese

レーザー推進マイクロ飛行機と複合領域の統合的最適化　　　　　　　　　　　　　　　
梶原逸朗, 矢部, 日本航空宇宙学会誌, 52, 608, 237, 242, 2004

水とレーザー駆動による紙飛行機　　　　　　　　　　　　　　　
矢部孝, 梶原逸朗, 日本航空宇宙学会誌, 51, 595, 208, 212, 2003

平成14年度加速度計則標準の現状と動向及び我が国産業界のニーズに関する調査研究報告書　　　　　　　　　　　　　　　
梶原逸朗, (社)日本機械工業連合会・(財)日本産業技術振興協会, 日機連14標準化-8, 2003

圧電フィルムによるOA機器の振動制御　　　　　　　　　　　　　　　
江連勝彦, 猿渡克巳, 梶原逸朗, 小野測器技報, 14, 6, 10, 2001

情報機器の構造設計に基づく制振技術
梶原逸朗, 機械の研究, 53, 12, 1223, 1230, 2001
養賢堂, Japanese

振動制御のためのスマート構造の設計　　　　　　　　　　　　　　　
梶原逸朗, 制振工学研究会 「2000技術交流会」資料集, 44, 50, 2000

情報機器の機構設計／制御の動向　　　　　　　　　　　　　　　
梶原逸朗, 日本機械学会講習会「機構制御の最先端と情報・医療福祉機器への応用」テキスト, 00-32, 45, 52, 2000

振動制御のためのスマート構造の設計　　　　　　　　　　　　　　　
梶原逸朗, 自動車技術会シンポジウム「自動車の振動騒音とうまくつきあう方法」, 10-00, 13, 19, 2000

制御性と安定性の向上を目指した構造と制御の同時設計
梶原逸朗, システム／制御／情報, 44, 11, 623, 631, 2000

構造系と制御系の最適設計　　　　　　　　　　　　　　　
梶原逸朗, 日本機械学会講習会「動システムの設計と最適化に関する先端技術」テキスト, 930-3, 95, 105, 1993

感度解析による最適設計　　　　　　　　　　　　　　　
梶原逸朗, 機械の研究, 43, 3, 351, 356, 1991
Japanese, Introduction scientific journal

機械工学のための力学　　　　　　　　　　　　　　　
梶原 逸朗
丸善出版, 2014, [Contributor]

シミュレーション辞典　　　　　　　　　　　　　　　
梶原 逸朗
日本シミュレーション学会, 2012, [Contributor]

制振工学ハンドブック　　　　　　　　　　　　　　　
梶原 逸朗
コロナ社, 2008, [Contributor]

機械工学のための数学I －基礎数学－　　　　　　　　　　　　　　　
梶原 逸朗
朝倉書店, 2007, [Contributor]

機械工学のための数学Ⅰ　　　　　　　　　　　　　　　
梶原 逸朗
朝倉書店, 2007, [Contributor]

構造工学ハンドブック　　　　　　　　　　　　　　　
梶原 逸朗
丸善, 2004, [Contributor]

最適設計ハンドブック　　　　　　　　　　　　　　　
梶原 逸朗
朝倉書店, 2003, [Contributor]

モード解析ハンドブック　　　　　　　　　　　　　　　
梶原 逸朗
コロナ社, 1999, [Contributor]

音・振動のモード解析と制御　　　　　　　　　　　　　　　
梶原 逸朗
日本音響学会編、音響テクノロジーシリーズ,コロナ社, 1996, [Contributor]

スパースデータ駆動モデリングを用いた非線形モデル予測制御: ディーゼルエンジンの吸排気システムへの適用　　　　　　　　　　　　　　　
矢作修一, 瀬戸洋紀, 米沢安成, 梶原逸朗
第66回自動制御連合講演会, 07 Oct. 2023, Japanese, Oral presentation
07 Oct. 2023 - 08 Oct. 2023

駆動系の振動制御における切り替え型ファジィ制御を用いたバックラッシの補償　　　　　　　　　　　　　　　
河野康平, 米沢平成, 梶原逸朗
第31回インテリジェント・システム・シンポジウム, 07 Sep. 2023, Japanese
07 Sep. 2023 - 08 Sep. 2023

仮想構造物を導入した階層構造物のモデルフリー振動制御　　　　　　　　　　　　　　　
吉川元人, 米沢安成, 福嶋祐人, 米沢平成, 梶原逸朗
Dynamics and Design Conference 2023, 31 Aug. 2023, Japanese
28 Aug. 2023 - 31 Aug. 2023

自動車駆動系制御における離散値制約への対応と性能評価　　　　　　　　　　　　　　　
伊藤義房, 平田将規, 米沢平成, 佐藤晶太, 波多野崇, 西留千晶, 梶原逸朗
Dynamics and Design Conference 2023, 30 Aug. 2023, Japanese
28 Aug. 2023 - 31 Aug. 2023

レーザー加振技術を用いた骨の弾性率推定　　　　　　　　　　　　　　　
菊池大, 岩崎幹大, 山田悟史, 東藤正浩, 米沢平成, 梶原逸朗
日本機械学会 第33回バイオフロンティア講演会, 17 Dec. 2022, Japanese, Oral presentation
17 Dec. 2022 - 18 Dec. 2022

打撃試験に基づくコンクリート材の減衰特性評価に関する基礎検討　　　　　　　　　　　　　　　
岩崎幹大, 菊池大, 澤口香織, 本田真也, 菊地優, 越川武晃, 石井建, 米沢平成, 梶原逸朗
日本機械学会 第20回評価・診断に関するシンポジウム, 02 Dec. 2022, Japanese, Oral presentation
01 Dec. 2022 - 02 Dec. 2022

誘電エラストマーアクチュエータを用いたアボカドの硬さ評価　　　　　　　　　　　　　　　
磯貝航, 梶原逸朗, 前田真吾, 細矢直基
Dynamics and Design Conference 2022, 05 Sep. 2022, Japanese, Oral presentation
05 Sep. 2022 - 08 Sep. 2022

オンライン型FRITを用いた二自由度制御系の適応パラメータチューニングによる目標値追従性能／外乱抑圧性能の向上　　　　　　　　　　　　　　　
坂井達成, 矢作修一, 梶原逸朗
Dynamics and Design Conference 2022, 05 Sep. 2022, Japanese, Oral presentation
05 Sep. 2022 - 08 Sep. 2022

マルチアクチュエータによる任意構造物のモデルフリー振動制御　　　　　　　　　　　　　　　
福嶋祐人, 佐藤友人, 米沢安成, 米沢平成, 梶原逸朗
Dynamics and Design Conference 2022, 05 Sep. 2022, Japanese, Oral presentation
05 Sep. 2022 - 08 Sep. 2022

自動車駆動系の振動制御における離散値制約への対応の検討　　　　　　　　　　　　　　　
平田将規, 波多野崇, 平松繁喜, 佐藤晶太, 西留千晶, 梶原逸朗, 米沢平成
Dynamics and Design Conference 2022, 05 Sep. 2022, Japanese, Oral presentation
05 Sep. 2022 - 08 Sep. 2022

実制御対象の数理モデルを用いないアクティブ振動制御装置の構築手法　　　　　　　　　　　　　　　
米沢安成, 米沢平成, 梶原逸朗
第17回運動と振動の制御シンポジウム(MoViC2021), 10 Dec. 2021, Japanese, Oral presentation
09 Dec. 2021 - 10 Dec. 2021

レーザー誘起プラズマによるインパルス加振を用いたマンゴーの非接触非破壊硬さ評価　　　　　　　　　　　　　　　
古怒田真悟, 荒井那由他, 梶原逸朗, 細矢直基
Dynamics and Design Conference 2021, 17 Sep. 2021, Japanese, Oral presentation
13 Sep. 2021 - 17 Sep. 2021

制御入力の更新タイミングに不確かさを有する自動車駆動系のアクティブ振動制御　　　　　　　　　　　　　　　
米沢平成, 西留千晶, 波多野崇, 平松繁喜, 梶原逸朗
Dynamics and Design Conference 2021, 15 Sep. 2021, Japanese, Oral presentation
13 Sep. 2021 - 17 Sep. 2021

音響レンズを用いたレーザー誘起プラズマ衝撃波による加振法（Lamb 波の生成）　　　　　　　　　　　　　　　
若田祥, 前川知輝, 梶原逸朗, Ambroziński Łukasz, Pieczonka Łukasz, 細矢直基
Dynamics and Design Conference 2021, 15 Sep. 2021, Japanese, Oral presentation
13 Sep. 2021 - 17 Sep. 2021

誘電エラストマーアクチュエータを用いた曲面を有する機械構造物の振動制御　　　　　　　　　　　　　　　
佐々木海詩, 比留田稔樹, 梶原逸朗, 細矢直基, 前田真吾
第63回自動制御連合講演会講演論文集, 21 Nov. 2020, Japanese, Oral presentation
21 Nov. 2020 - 22 Nov. 2020

レーザー加振/計測を用いたコンクリートの硬化モニタリング　　　　　　　　　　　　　　　
佐々木源明, 竹本喜昭, 齊藤 亮介, 梶原逸朗
第63回自動制御連合講演会講演論文集, 21 Nov. 2020, Japanese, Oral presentation
21 Nov. 2020 - 22 Nov. 2020

仮想構造物を導入したマルチアクチュエータによるモデルフリー振動制御　　　　　　　　　　　　　　　
佐藤友人, 米沢平成, 米沢安成, 梶原逸朗
第63回自動制御連合講演会講演論文集, 21 Nov. 2020, Japanese, Oral presentation
21 Nov. 2020 - 22 Nov. 2020

音響レンズを用いたレーザー誘起プラズマ衝撃波による加振法　　　　　　　　　　　　　　　
細矢直基, 吉田侑樹, 前田真吾, 梶原逸朗
Dynamics and Design Conference 2020, 01 Sep. 2020, Japanese, Oral presentation
01 Sep. 2020 - 04 Sep. 2020

可変延長制御周期による影響を考慮した自動車駆動系のアクティブ振動制御　　　　　　　　　　　　　　　
米沢平成, 梶原逸朗, 西留千晶, 波多野崇, 坂田将人, 平松繁喜
Dynamics and Design Conference 2020, 01 Sep. 2020, Japanese, Oral presentation
01 Sep. 2020 - 04 Sep. 2020

マルチ誘電エラストマーアクチュエータを用いた膜構造の振動制御　　　　　　　　　　　　　　　
石原宏基, 比留田稔樹, 細矢直基, 前田真吾, 梶原逸朗
Dynamics and Design Conference 2020, 01 Sep. 2020, Japanese, Oral presentation
01 Sep. 2020 - 04 Sep. 2020

誘電エラストマーアクチュエータ加振に基づくりんごの振動計測と硬さ評価　　　　　　　　　　　　　　　
比留田稔樹, 細矢直基, 前田真吾, 梶原逸朗
Dynamics and Design Conference 2020, 01 Sep. 2020, Japanese, Oral presentation
01 Sep. 2020 - 04 Sep. 2020

制御周期制約下における自動車駆動系のバックラッシ補償　　　　　　　　　　　　　　　
米沢平成, 梶原逸朗, 西留千晶, 波多野崇, 坂田将人, 平松繁
運動と振動の制御シンポジウム2019, 04 Dec. 2019, Japanese, Oral presentation
04 Dec. 2019 - 06 Dec. 2019

非線形性を有する自動車操舵系のモデル化とモータによる角度追従制御　　　　　　　　　　　　　　　
近藤俊朗, 米沢平成, 西留千晶, 梶原逸朗, 加藤真, 近藤秀一, 波多野崇, 坂田将人, 平松繁喜
第62回自動制御連合講演会講演論文集, 08 Nov. 2019, Japanese, Oral presentation
08 Nov. 2019 - 10 Nov. 2019

誘電エラストマーアクチュエータによる加振を用いたりんごの振動特性計測　　　　　　　　　　　　　　　
比留田稔樹, 細矢直基, 前田真吾, 梶原逸朗
第62回自動制御連合講演会講演論文集, 08 Nov. 2019, Japanese, Oral presentation
08 Nov. 2019 - 10 Nov. 2019

物理機能モデルを活用した非線形システムの状態量推定　　　　　　　　　　　　　　　
米沢平成, 梶原逸朗, 西留千晶, 波多野崇, 坂田将人, 平松繁喜
第62回自動制御連合講演会講演論文集, 08 Nov. 2019, Japanese, Oral presentation
08 Nov. 2019 - 10 Nov. 2019

非接触レーザー加振／計測技術を用いたタイル構造の健全性評価　　　　　　　　　　　　　　　
鈴木健吾, 佐々木源明, 齊藤亮介, 北垣亮馬, 梶原逸朗
日本機械学会 2019年度年次大会, 09 Sep. 2019, Japanese, Oral presentation
09 Sep. 2019 - 11 Sep. 2019

レーザー音響加振／計測技術を用いたパイプ構造の損傷検知　　　　　　　　　　　　　　　
梶原逸朗, 秋田涼佑, 細矢直基
日本機械学会 2019年度年次大会, 09 Sep. 2019, Japanese, Oral presentation
09 Sep. 2019 - 11 Sep. 2019

実験モード解析によるポポー果実の非接触非破壊硬度評価　　　　　　　　　　　　　　　
荒井那由他, 高橋健太郎, 細矢直基, 梶原逸朗
Dynamics and Design Conference 2019, 27 Aug. 2019, Japanese, Oral presentation
27 Aug. 2019 - 30 Aug. 2019

パラメータの不確かさを有するアクチュエータを用いたモデルフリー振動制御　　　　　　　　　　　　　　　
米沢安成, 米沢平成, 梶原逸朗
Dynamics and Design Conference 2019, 27 Aug. 2019, Japanese, Oral presentation
27 Aug. 2019 - 30 Aug. 2019

NOx排出量規制を考慮したディーゼルエンジンの運用コスト低減のための最適制御　　　　　　　　　　　　　　　
三輪 柚里江, 塙 哲史, 佐藤 淳一, 花村 良文, 石塚 真一, 梶原逸朗
Dynamics and Design Conference 2019, 27 Aug. 2019, Japanese, Oral presentation
27 Aug. 2019 - 30 Aug. 2019

誘電エラストマーアクチュエータを用いた膜構造の振動制御　　　　　　　　　　　　　　　
比留田稔樹, 平原隼人, 梶原逸朗, 細矢直基, 前田真吾
Dynamics and Design Conference 2019, 27 Aug. 2019, Japanese, Oral presentation
27 Aug. 2019 - 30 Aug. 2019

レーザー誘起プラズマで生成された衝撃波によるインパルス加振を用いた透明高分子材料へのLamb波生成　　　　　　　　　　　　　　　
勝又翼, 細矢直基, 神田淳, 梶原逸朗
第17回評価・診断に関するシンポジウム, 06 Dec. 2018, Japanese, Oral presentation
[Domestic Conference]

任意構造物の制振を可能とするモデルフリー振動制御　　　　　　　　　　　　　　　
米沢平成, 梶原逸朗, 大西諒史, 米沢安成
第61回自動制御連合講演会, 18 Nov. 2018, Japanese, Oral presentation
[Domestic Conference]

実験モード解析による「太陽のタマゴ」の硬さ評価　　　　　　　　　　　　　　　
細矢直基, 出西勇気, 高橋健太郎, 梶原逸朗
Dynamics and Design Conference 2018, 28 Aug. 2018, Japanese, Oral presentation
[Domestic Conference]

DEAによる構造物の振動制御に関する研究(DEAの積層構成と制御効果の考察)　　　　　　　　　　　　　　　
平原隼人, 梶原逸朗, 細矢直基, 前田真吾
Dynamics and Design Conference 2018, 28 Aug. 2018, Japanese, Oral presentation
[Domestic Conference]

バックラッシ特性を再現する自動車駆動系の基礎実験装置と振動制御　　　　　　　　　　　　　　　
米沢平成, 梶原逸朗, 佐藤晶太, 西留千晶, 坂田将人, 波多野崇, 平松繁喜
Dynamics and Design Conference 2018, 28 Aug. 2018, Japanese, Oral presentation
[Domestic Conference]

混合H2/H∞スライディングモード制御によるギヤバックラッシを含む自動車駆動系の振動制御　　　　　　　　　　　　　　　
米沢平成, 梶原逸朗, 佐藤晶太, 西留千晶
第50回計測自動制御学会北海道支部学術講演会, 08 Mar. 2018, Japanese, Oral presentation
[Domestic Conference]

同次指数安定化制御則に基づく仮想構造を利用した任意構造物の振動制御　　　　　　　　　　　　　　　
大西諒史, 梶原逸朗
第60回自動制御連合講演会講演論文集, 10 Nov. 2017, Japanese, Oral presentation
[Domestic Conference]

レーザーアブレーションを用いた Lamb波の生成（金属チップによる損傷防止）　　　　　　　　　　　　　　　
奥村洋平, 細矢直基, 神田淳, 岩﨑紗綾, 梶原逸朗
Dynamics and Design Conference 2017, 29 Aug. 2017, Japanese, Oral presentation
[Domestic Conference]

レーザーを用いた音響加振に基づく閉空間内の異物検知　　　　　　　　　　　　　　　
小田一心, 梶原逸朗, 細矢直基
Dynamics and Design Conference 2017, 29 Aug. 2017, Japanese, Oral presentation
[Domestic Conference]

非線形性を有する自動車駆系の加速度制御　　　　　　　　　　　　　　　
佐藤晶太, 梶原逸朗, 西留千晶, 坂田将人, 波多野崇, 平松繁
運動と振動の制御シンポジウム2017, 29 Aug. 2017, Japanese, Oral presentation
[Domestic Conference]

ディーゼルエンジンにおけるNOx目標値のオンライン最適化　　　　　　　　　　　　　　　
佐々木アスカ, 塙哲史, 佐藤淳一, 花村良文, 石塚真一, 梶原逸朗
運動と振動の制御シンポジウム 2017, 29 Aug. 2017, Japanese, Oral presentation
[Domestic Conference]

ディー ゼルエンジン排出NOxソフトセンサのオンライン最適化　　　　　　　　　　　　　　　
平河佑樹, 梶原逸朗, 佐々木アスカ, 石塚真一, 佐藤淳一, 花村良文
自動車技術会 2016年秋 季大会 産学ポスターセッション, 21 Oct. 2016, Japanese, Oral presentation
[Domestic Conference]

制御性指標に基づくスマート構造のアクチュエタ配置最適化　　　　　　　　　　　　　　　
北畠茂幹, 梶原逸朗, 有坂寿洋
Dynamics and Design Conference 2016, 23 Aug. 2016, Japanese, Oral presentation
[Domestic Conference]

ディーセルエンジンのNOx制御に向けたNOxソフトセンサのセルフチューニング手法　　　　　　　　　　　　　　　
平河佑樹, 石塚真一, 梶原逸朗, 佐藤淳一, 花村良文
Dynamics and Design Conference 2016, 23 Aug. 2016, Japanese, Oral presentation
[Domestic Conference]

レーザプラズマ音響加振・計測による構造ヘルスモニタリング　　　　　　　　　　　　　　　
秋田涼佑, 梶原逸朗, 細矢直基
Dynamics and Design Conference 2016, 23 Aug. 2016, Japanese, Oral presentation
[Domestic Conference]

レーザーを用いた完全非接触でのLamb波生成可視化技術の開発　　　　　　　　　　　　　　　
神田淳, 細矢直基, 梶原逸朗
可視化情報全国講演(京都2015), 10 Oct. 2015, Japanese, Oral presentation
[Domestic Conference]

有限要素モデルと計測データに基づくシステムのモデル化と制御　　　　　　　　　　　　　　　
佐藤聡祐, 梶原逸朗, 有坂寿洋
第25回設計工学・システム部門 講演会, 23 Sep. 2015, Japanese, Oral presentation
[Domestic Conference]

モデルベースコントローラの極への摂動を利用した動特性変動に対するリアルタイムチューニング（実験による検 証）　　　　　　　　　　　　　　　
古谷圭一郎, 石塚真一, 梶原逸朗
Dynamics and Design Conference 2015, 25 Aug. 2015, Japanese, Oral presentation
[Domestic Conference]

MEMS加速度計を用いたモデルフリー振動制御手法　　　　　　　　　　　　　　　
伊藤陸, 梶原逸朗, 金堂雅彦
Dynamics and Design Conference 2015, 25 Aug. 2015, Japanese, Oral presentation
[Domestic Conference]

高出力レーザーによる音響加振技術を用いた構造ヘルスモニタリング　　　　　　　　　　　　　　　
柴田真太朗, 張月琳, 梶原逸朗, 細矢直基
Dynamics and Design Conference 2015, 25 Aug. 2015, Japanese, Oral presentation
[Domestic Conference]

スライディングモード制御に基づく仮想構造を用いたモデルフリー振動制御　　　　　　　　　　　　　　　
佐藤周也, 梶原逸朗, 金堂雅彦, 川野順一
Dynamics and Design Conference 2015, 25 Aug. 2015, Japanese, Oral presentation
[Domestic Conference]

圧電フィルムを用いた膜構造のアクティブ振動制御　　　　　　　　　　　　　　　
比留田稔樹, 張月琳, 梶原逸朗, 細矢直基
第27回「電磁力関連のダイナミクス」シンポジウム講演論文集, 14 May 2015, Japanese, Oral presentation
[Domestic Conference]

有限要素解析に基づく弾性率分布を持つ肝臓モデルのMREシミュレーション　　　　　　　　　　　　　　　
黒田啓介, 梶原逸朗, 但野茂, 菅幹生, 宮内隆太郎
第27回バイオエンジニアリング講演会, 09 Jan. 2015, Japanese, Oral presentation
[Domestic Conference]

非接触レー ザー加振を用いた振動計測に基づくアルミニウム平板の損傷検知　　　　　　　　　　　　　　　
伊藤祥彰, Feblil Huda, 梶原逸朗, 細矢直基
第13回評価・診断に関するシンポジウム, 11 Dec. 2014, Japanese, Oral presentation
[Domestic Conference]

アクチュエータモデルに仮想構造を導入したモデルフリー振動制御手法　　　　　　　　　　　　　　　
佐藤周也, 伊藤陸, 梶原逸朗, 金堂雅彦
第57回自動制御連合講演会, 10 Nov. 2014, Japanese, Oral presentation
[Domestic Conference]

モデルベースコントローラの極への摂動を利用した動特性変動に対するリアルタイムチューニング　　　　　　　　　　　　　　　
古谷圭一郎, 石塚真一, 梶原逸朗
第57回自動制御連合講演会, 10 Nov. 2014, Japanese, Oral presentation
[Domestic Conference]

同時摂動確率近似を用いたディーゼルエンジンのEGR/VNT制御　　　　　　　　　　　　　　　
石塚真一, 佐藤淳一, 梶原逸朗
第57回自動制御連合講演会, 10 Nov. 2014, Japanese, Oral presentation
[Domestic Conference]

LQG制御則に基づくセルフセンシングモデルフリー振動制御(実験による特性評価)　　　　　　　　　　　　　　　
伊藤陸, 佐藤周也, 梶原逸朗, 金堂雅彦, 松本圭一郎
Dynamics and Design Conference 2014, 26 Aug. 2014, Japanese, Oral presentation
[Domestic Conference]

PC筐体の振動抑制に向けたスマート構造システムの最適化　　　　　　　　　　　　　　　
古谷圭一郎, 佐藤聡祐, 梶原逸朗, 有坂洋寿, 三枝高志
Dynamics and Design Conference 2014, 26 Aug. 2014, Japanese, Oral presentation
[Domestic Conference]

非接触レーザー加振法を用いた膜構造のヘルスモニタリング（モード信頼性評価基準およびRT法を用いた評価方法の検討）　　　　　　　　　　　　　　　
新里淳, 梶原逸朗, Feblil Huda, 細矢直基
Dynamics and Design Conference 2014, 26 Aug. 2014, Japanese, Oral presentation
[Domestic Conference]

スマート構造を用いたＰＣ筐体のアクティブ振動制御　　　　　　　　　　　　　　　
古谷圭一郎, 梶原逸朗, 佐藤 聡祐, 有坂寿洋, 三枝高志
IIP2014情報・知能・精密機器部門講演会, 18 Mar. 2014, Japanese, Oral presentation
[Domestic Conference]

有限要素解析による肝臓モデルのMREシミュレーション　　　　　　　　　　　　　　　
富田直, 梶原逸朗, 但野茂, 横田秀夫, 中村玄, 菅幹生
第26回バイオエンジニアリング講演会, 11 Jan. 2014, Japanese, Oral presentation
[Domestic Conference]

同時摂動確率近似によるモデルフリー適応PID制御　　　　　　　　　　　　　　　
石塚真一, 梶原逸朗
第56回自動制御連合講演会, 16 Nov. 2013, Japanese, Oral presentation
[Domestic Conference]

同時摂動確率近似によるモデルベースコントローラのチューニング　　　　　　　　　　　　　　　
古谷圭一郎, 石塚真一, 梶原逸朗
第56回自動制御連合講演会, 16 Nov. 2013, Japanese, Oral presentation
[Domestic Conference]

アクティブマウントによるHDDシステムの外部振動遮断　　　　　　　　　　　　　　　
中嶋渉, 梶原逸朗, 中村滋男, 吉川紀夫
第56回自動制御連合講演会, 16 Nov. 2013, Japanese, Oral presentation
[Domestic Conference]

LQG制御側に基づくセルフセンシングモデルフリー振動制御　　　　　　　　　　　　　　　
大北竜平, 矢作修一, 梶原逸朗, 金堂雅彦, 松本圭一郎
第13回運動と振動の制御シンポジウム, 27 Aug. 2013, Japanese, Oral presentation
[Domestic Conference]

修正MPCによるディーゼルエンジンのEGR-VNT協調制御　　　　　　　　　　　　　　　
西留千晶, 佐藤淳一, 花村良文, 梶原逸朗
第13回運動と振動の制御シンポジウム, 27 Aug. 2013, Japanese, Oral presentation
[Domestic Conference]

粘弾性体の有限要素解析によるMREシミレーション　　　　　　　　　　　　　　　
富田直, 鈴木逸人, 梶原逸朗, 但野茂
Dynamics and Design Conference 2013, 26 Aug. 2013, Japanese, Oral presentation
[Domestic Conference]

パルスレーザーを用いた高分子材料の振動試験　　　　　　　　　　　　　　　
馬場駿, 細矢直基, 前田真吾, 梶原逸朗
Dynamics and Design Conference 2013, 26 Aug. 2013, Japanese, Oral presentation
[Domestic Conference]

非接触レーザー加振法を用いた膜構造のヘルスモニタリング　　　　　　　　　　　　　　　
新里淳, 梶原逸朗, 細矢直基, Feblil Huda
Dynamics and Design Conference 2013, 26 Aug. 2013, Japanese, Oral presentation
[Domestic Conference]

パッシブ／アクティブマウント機構によるHDDシステムの外部振動遮断　　　　　　　　　　　　　　　
中嶋渉, 古谷圭一郎, 梶原逸朗, 中村滋男, 吉川紀夫
IIP2013情報・知能・精密機器部門講演会, 22 Mar. 2013, Japanese, Oral presentation
[Domestic Conference]

Active feed-forward cancellationに基づくセルフセンシング・モデルフリー振動制御　　　　　　　　　　　　　　　
藪井将太, 梶原逸朗, 矢作修一
IIP2013情報・知能・精密機器部門講演会, 22 Mar. 2013, Japanese, Oral presentation
[Domestic Conference]

MRE評価に向けた生体模擬ファントムの有限要素法振動解析　　　　　　　　　　　　　　　
富田直, 鈴木逸人, 梶原逸朗, 但野茂
第11回評価・診断に関するシンポジウム, 10 Dec. 2012, Japanese, Oral presentation
[Domestic Conference]

レーザーブレイクダウンによる非接触加振法を用いた膜構造の振動モード実験　　　　　　　　　　　　　　　
新里淳, 梶原逸朗, 細矢直基
第11回評価・診断に関するシンポジウム, 10 Dec. 2012, Japanese, Oral presentation
[Domestic Conference]

DVFBに基づくセンサレスモデルフリー振動制御(実験による検証)　　　　　　　　　　　　　　　
矢作修一, 大北竜平, 梶原逸朗, 金堂雅彦, 松本圭一郎
第55回自動制御連合講演会, 18 Nov. 2012, Japanese, Oral presentation
[Domestic Conference]

マイクロスマート構造のパッシブ／アクティブ併用振動制御(非接触レーザー加振システムによる制振特性評価)　　　　　　　　　　　　　　　
朱艶, 梶原逸朗, 細矢直基
第55回自動制御連合講演会, 18 Nov. 2012, Japanese, Oral presentation
[Domestic Conference]

HDDスマートヘッドアクチュエータののパッシブ／アクティブ併用振動制御　　　　　　　　　　　　　　　
中嶋渉, 梶原逸朗
第55回自動制御連合講演会, 18 Nov. 2012, Japanese, Oral presentation
[Domestic Conference]

micro-MRIによる高分子ゲルの3次元MRE画像　　　　　　　　　　　　　　　
鈴木逸人, 藤崎和弘, 菅幹生, 中村玄, 梶原逸朗, 但野茂
第23回バイオフロンティア講演会, Oct. 2012, Japanese, Oral presentation
[Domestic Conference]

マイクロスマート複合材の統合最適化とレーザー加振技術による振動制御性能評価　　　　　　　　　　　　　　　
渡邉一希, 本田真也, 成田吉弘, 梶原逸朗
Dynamics and Design Conference 2012, 20 Sep. 2012, Japanese, Oral presentation
[Domestic Conference]

制御対象のモデルを要しない汎用センサレスモデルフリー振動制御法　　　　　　　　　　　　　　　
矢作修一, 佐藤祐介, 梶原逸朗, 金堂雅彦
日本機械学会2012年度年次大会, 09 Sep. 2012, Japanese, Oral presentation
[Domestic Conference]

非接触レーザー加振技術によるボルト緩み検知に関する研究　　　　　　　　　　　　　　　
杉本雅俊, 竹内将人, 梶原逸朗, 細矢直基, 河村庄造
日本機械学会2012年度年次大会, 09 Sep. 2012, Japanese, Oral presentation
[Domestic Conference]

非接触レーザー加振技術を用いたモーメント加振法による周波数応答関数の推定　　　　　　　　　　　　　　　
小林明莉, 滝口康太, 細矢直基, 梶原逸朗
日本機械学会2012年度年次大会, 09 Sep. 2012, Japanese, Oral presentation
[Domestic Conference]

レーザーアブレーションにより生成されるパルス音源を用いた音響加振法　　　　　　　　　　　　　　　
井上龍生, 細矢直基, 梶原逸朗
日本機械学会2012年度年次大会, 09 Sep. 2012, Japanese, Oral presentation
[Domestic Conference]

mico-MRIによる2層アガロースゲルのMRE画像　　　　　　　　　　　　　　　
鈴木逸人, 藤崎和弘, 菅幹生, 中村玄, 王海兵, 梶原逸朗, 但野茂
日本機械学会2012年度年次大会, 09 Sep. 2012, Japanese, Oral presentation
[Domestic Conference]

高分子ゲルのMRE画像に対する加振条件　　　　　　　　　　　　　　　
鈴木逸人, 藤崎和弘, 菅幹生, 中村玄, 王海兵, 梶原逸朗, 但野茂
第24回バイオエンジニアリング講演会, 07 Jan. 2012, Japanese, Oral presentation
[Domestic Conference]

非接触レーザー加振による膜構造の振動モード特性評価　　　　　　　　　　　　　　　
西埜亮太, 梶原逸朗, 細矢直基, 西留千晶
第10回評価・診断に関するシンポジウム, 14 Dec. 2011, Japanese, Oral presentation
[Domestic Conference]

レーザー加振を用いたスマートマイクロ複合材の振動制御性の評価　　　　　　　　　　　　　　　
本田真也, 成田吉弘, 梶原逸朗, 中村哲司
第36回複合材料シンポジウム, 20 Oct. 2011, Japanese, Oral presentation
[Domestic Conference]

超小型スマート構造の振動制御と非接触レーザー加振による制振特性評価　　　　　　　　　　　　　　　
朱艶, 中村哲司, 梶原逸朗
Dynamics and Design Conference 2011, 05 Sep. 2011, Japanese, Oral presentation
[Domestic Conference]

非接触レーザー加振システムによる膜構造の振動計測　　　　　　　　　　　　　　　
梶原逸朗, 小原賢也
Dynamics and Design Conference 2011, 05 Sep. 2011, Japanese, Oral presentation
[Domestic Conference]

積層パラメータを用いたスマート複合材の統合最適設計　　　　　　　　　　　　　　　
小坂亙, 本田真也, 成田吉弘, 梶原逸朗
Dynamics and Design Conference 2011, 05 Sep. 2011, Japanese, Oral presentation
[Domestic Conference]

レーザー加振技術を用いた回転円板の実稼働時振動計測　　　　　　　　　　　　　　　
宮本大資, 梶原逸朗, 細矢直基
Dynamics and Design Conference 2011, 05 Sep. 2011, Japanese, Oral presentation
[Domestic Conference]

レーザーアブレーション加振による水中構造物の非接触振動試験　　　　　　　　　　　　　　　
矢作修一, 細矢直基, 梶原逸朗
Dynamics and Design Conference 2011, 05 Sep. 2011, Japanese, Oral presentation
[Domestic Conference]

レーザーブレイクダウンによる点音源を用いた微小空間の音響加振法　　　　　　　　　　　　　　　
永田将希, 細矢直基, 梶原逸朗
Dynamics and Design Conference 2011, 05 Sep. 2011, Japanese, Oral presentation
[Domestic Conference]

スマート構造を用いたHDDヘッド駆動機構の高周波帯域振動制御　　　　　　　　　　　　　　　
中村哲司, 梶原逸朗, 有坂寿洋
第12回運動と振動の制御シンポジウム, 29 Jun. 2011, Japanese, Oral presentation
[Domestic Conference]

非接触レーザー加振/計測技術による超小型スマート構造の制振特性評価　　　　　　　　　　　　　　　
朱艶, 中村哲司, 梶原逸朗
第12回運動と振動の制御シンポジウム, 29 Jun. 2011, Japanese, Oral presentation
[Domestic Conference]

レーザー加振技術による小型スマート構造の制振特性評価　　　　　　　　　　　　　　　
朱艶, 中村哲司, 梶原逸朗
IIP2011情報・知能・精密機器部門講演会, 22 Mar. 2011, Japanese, Oral presentation
[Domestic Conference]

打撃試験を用いた高周波帯域の特性変動検知に基づくボルト緩み診断　　　　　　　　　　　　　　　
細川恭彦, 細矢直基, 梶原逸朗
日本機械学会関東支部第17期総会講演会, 18 Mar. 2011, Japanese, Oral presentation
[Domestic Conference]

スマート構造を用いたHDDキャリッジアームの高周波帯域振動制御　　　　　　　　　　　　　　　
中村哲司, 梶原逸朗, 有坂寿洋
第43回計測自動制御学会北海道支部学術講演会, 02 Mar. 2011, Japanese, Oral presentation
[Domestic Conference]

レーザー加振実験およびFEMによる膜構造の振動特性評価　　　　　　　　　　　　　　　
西埜亮太, 小原賢也, 梶原逸朗
第53回自動制御連合講演会, 06 Nov. 2010, Japanese, Oral presentation
[Domestic Conference]

ディーゼルエンジンのモデル予測型EGR－VNT協調制御に関する研究　　　　　　　　　　　　　　　
岩崎晃, 梶原逸朗, 西留千晶, 花村良文, 高田博
第53回自動制御連合講演会, 04 Nov. 2010, Japanese, Oral presentation
[Domestic Conference]

スマート複合材料の振動制御に関する統合最適化　　　　　　　　　　　　　　　
本田真也, 成田吉弘, 梶原逸朗
第23回計算力学講演会, 25 Sep. 2010, Japanese, Oral presentation
[Domestic Conference]

HDDスマートヘッド機構におけるセンサ／アクチュエータ／制御の最適化　　　　　　　　　　　　　　　
中村哲司, 梶原逸朗, 有坂寿洋
第23回計算力学講演会, 23 Sep. 2010, Japanese, Oral presentation
[Domestic Conference]

レーザー加振技術を用いた高周波帯域の特性変動検知に基づくヘルスモニタリング　　　　　　　　　　　　　　　
宮本大資, 梶原逸朗, 細矢直基, 古川崇人, 櫻井泰貴
Dynamics and Design Conference 2010, 17 Sep. 2010, Japanese, Oral presentation
[Domestic Conference]

力計測をセンサレス化したレーザー加振実験に基づくFRF計測　　　　　　　　　　　　　　　
細矢直基, 梶原逸朗, 細川恭彦
Dynamics and Design Conference 2010, 15 Sep. 2010, Japanese, Oral presentation
[Domestic Conference]

圧電素子を用いたエネルギーハーべスティングの高効率化に関する研究　　　　　　　　　　　　　　　
櫻井努, 梶原逸朗, 原田宏幸, 新井浩成
Dynamics and Design Conference 2010, 14 Sep. 2010, Japanese, Oral presentation
[Domestic Conference]

HDDスマートヘッド機構の最適設計と高周波帯域振動制御　　　　　　　　　　　　　　　
中村哲司, 梶原逸朗, 有坂寿洋, 高橋真史
Dynamics and Design Conference 2010, 14 Sep. 2010, Japanese, Oral presentation
[Domestic Conference]

SMAアクチュエータを用いた水中推進ロボット　　　　　　　　　　　　　　　
原田宏幸, 梶原逸朗, 黒川貴裕
Dynamics and Design Conference 2010, 14 Sep. 2010, Japanese, Oral presentation
[Domestic Conference]

打撃試験を用いた高周波帯域の特性変動検知に基づくヘルスモニタリング　　　　　　　　　　　　　　　
細川恭彦, 細矢直基, 梶原逸朗
Dynamics and Design Conference 2010, 14 Sep. 2010, Japanese, Oral presentation
[Domestic Conference]

HDDのスマート構造化と機構最適化による高周波帯域振動制御　　　　　　　　　　　　　　　
高橋真史, 梶原逸朗, 有坂寿洋, 中村哲司
IIP2010情報・知能・精密機器部門講演会, 17 Mar. 2010, Japanese, Oral presentation
[Domestic Conference]

セミアクティブサスペンションによる車両の振動制御　　　　　　　　　　　　　　　
宮本大資, 梶原逸朗, 新藤広樹
第42回計測自動制御学会北海道支部学術講演会, 22 Feb. 2010, Japanese, Oral presentation
[Domestic Conference]

レーザー加振技術を用いた高周波振動計測に基づくヘルスモニタリング　　　　　　　　　　　　　　　
梶原逸朗, 細矢直基
第8回評価・診断に関するシンポジウム, 10 Dec. 2009, Japanese, Oral presentation
[Domestic Conference]

HDD高密度化のための振動制御と革新的振動計測技術　　　　　　　　　　　　　　　
梶原逸朗
イノベーションジャパン2009 －大学見本市, 16 Sep. 2009, Japanese, Oral presentation
[Domestic Conference]

レーザーを用いたインパルス加振実験法による振動計測（周波数応答関数測定の高精度化）　　　　　　　　　　　　　　　
細矢直基, 反町仁, 梶原逸朗, 原口大輔
Dynamics and Design Conference 2009, 2009, Japanese, Oral presentation
[Domestic Conference]

レーザー双方向通信によるマイクロ移動体の遠隔制御　　　　　　　　　　　　　　　
梶原逸朗, 中野孝亮
Dynamics and Design Conference 2009, 2009, Japanese, Oral presentation
[Domestic Conference]

レーザーによる高周波振動計測に基づくヘルスモニタリング　　　　　　　　　　　　　　　
梶原逸朗, 細矢直基
日本機械学会 第11回運動と振動の制御シンポジウム, 2009, Japanese, Oral presentation
[Domestic Conference]

ILQ設計に基づくディーゼルエンジンのEGR-VNT協調制御　　　　　　　　　　　　　　　
西留千晶, 佐藤淳一, 梶原逸朗, 花村良文, 高田 博
日本機械学会 第11回運動と振動の制御シンポジウム, 2009, Japanese, Oral presentation
[Domestic Conference]

慣性質量型圧電アクチュエータによる周波数帯域分離型ロバスト振動制御　　　　　　　　　　　　　　　
梶原逸朗, 加藤弘敏, 金堂雅彦, 佐藤裕介
第20回電磁力関連のダイナミクスシンポジウム, 2008, Japanese, Oral presentation
[Domestic Conference]

HDDのスマート構造化による振動制御とサーボ性能の向上　　　　　　　　　　　　　　　
梶原逸朗, 内山敏夫, 有坂寿洋
Dynamics and Design Conference 2008, 2008, Japanese, Oral presentation
[Domestic Conference]

HDDにおけるサーボの高性能化を目指したスマート構造の最適設計　　　　　　　　　　　　　　　
高橋真史, 内山敏夫, 梶原逸朗, 有坂寿洋
Dynamics and Design Conference 2008, 2008, Japanese, Oral presentation
[Domestic Conference]

レーザーによるマイクロ移動体の遠隔制御とエネルギー伝送　　　　　　　　　　　　　　　
中野孝亮, 小幡倫世, 梶原逸朗
Dynamics and Design Conference 2008, 2008, Japanese, Oral presentation
[Domestic Conference]

レーザーを用いたインパルス加振実験法による振動計測　　　　　　　　　　　　　　　
細矢直基, 梶原逸朗
Dynamics and Design Conference 2008, 2008, Japanese, Oral presentation
[Domestic Conference]

スマートリンク機構における特性変動を考慮した制御系最適化　　　　　　　　　　　　　　　
梶原逸朗, 土屋亮, 石塚真一
第21回計算力学講演会, 2008, Japanese, Oral presentation
[Domestic Conference]

HDDにおけるヘッド機構のスマート構造化と最適設計　　　　　　　　　　　　　　　
高橋真史, 梶原逸朗, 有坂寿洋
第8回最適化シンポジウム, 2008, Japanese, Oral presentation
[Domestic Conference]

Gain-scheduled control of smart structures with dynamic characteristic variation　　　　　　　　　　　　　　　
World Forum on Smart Materials and Smart Structures Technology, 2007

周波数帯域分離型並列コントローラによる広帯域ロバスト協調制御法　　　　　　　　　　　　　　　
梶原逸朗, 加藤弘敏, 金堂雅彦, 佐藤裕介
第10回運動と振動の制御シンポジウム, 2007, Japanese, Oral presentation
[Domestic Conference]

特性変動を有する外乱を受けるスマート構造の振動制御法　　　　　　　　　　　　　　　
小野仁章, 梶原逸朗
Dynamics and Design Conference 2007, 2007, Japanese, Oral presentation
[Domestic Conference]

レーザーエネルギー伝送による小型移動体の遠隔駆動　　　　　　　　　　　　　　　
中野孝亮, 大北哲也, 梶原逸朗
Dynamics and Design Conference 2007, 2007, Japanese, Oral presentation
[Domestic Conference]

レーザーを用いた新しい加振実験方法　　　　　　　　　　　　　　　
小幡倫世, 梶原逸朗
Dynamics and Design Conference 2007, 2007, Japanese, Oral presentation
[Domestic Conference]

正実性を利用したスマート構造による振動制御法　　　　　　　　　　　　　　　
片岡隆仁, 粟生真行, 梶原逸朗
Dynamics and Design Conference 2007, 2007, Japanese, Oral presentation
[Domestic Conference]

Remote Control of Laser-Driven Micro-Vehicles　　　　　　　　　　　　　　　
4th International Symposium on Beamed Energy Propulsion, 2006

Optimization of vibration control system for smart structures with disturbance characteristic variation　　　　　　　　　　　　　　　
11th AIAA/ISSMO Multidisciplinary Analysis and Optimization Conference, 2006

人間の聴覚特性を考慮した放射騒音抑制のためのスマート構造最適化　　　　　　　　　　　　　　　
小野仁章, 梶原逸朗
Dynamics and Design Conference 2006, 2006, Japanese, Oral presentation
[Domestic Conference]

マイクロ移動体のための光学システムの開発　　　　　　　　　　　　　　　
大北哲也, 梶原逸朗
Dynamics and Design Conference 2006, 2006, Japanese, Oral presentation
[Domestic Conference]

特性変動を有するシステムのスマート構造による適応制御　　　　　　　　　　　　　　　
土屋亮, 梶原逸朗
日本機械学会2006年度年次大会, 2006, Japanese, Oral presentation
[Domestic Conference]

外乱特性変動をともなうスマート構造の複合領域最適化　　　　　　　　　　　　　　　
小野仁章, 梶原逸朗
第49回自動制御連合講演会, 2006, Japanese, Oral presentation
[Domestic Conference]

振動燃焼の物理モデルとその能動的制御システムの構築　　　　　　　　　　　　　　　
井出智広, 佐藤博之, 梶原逸朗, 林光一
熱工学コンファレンス2006, 2006, Japanese, Oral presentation
[Domestic Conference]

Suppression of Combustion Noise and Combustion Oscillation by Thermo-Acoustic Active Control Using Secondary Flame　　　　　　　　　　　　　　　
ASME Turbo Expo 2005, 2005

Remote Control of Laser-Driven Micro-Vehicles　　　　　　　　　　　　　　　
4th International Symposium on Beamed Energy Propulsion, 2005, Poster presentation

Efficiency of Air Injection on Stability and Emission Controls in Premixed Combustion　　　　　　　　　　　　　　　
20th International Colloquium on the Dynamics of Explosions and Reactive Systems, 2005

Multidisciplinary Design Optimization of Smart Structures for Vibration and Sound Suppression　　　　　　　　　　　　　　　
11th Asia-Pacific Vibration Conference, 2005

特性変動を有するスマートマニピュレータの制振性能向上を目指した制御機構最適化　　　　　　　　　　　　　　　
土屋亮, 梶原逸朗
Dynamics and Design Conference 2005, 2005, Japanese, Oral presentation
[Domestic Conference]

レーザーによる移動体の遠隔制御に関する研究　　　　　　　　　　　　　　　
大北哲也, 星野健太郎, 梶原逸朗
Dynamics and Design Conference 2005, 2005, Japanese, Oral presentation
[Domestic Conference]

スマート構造の複合領域最適化による振動・騒音の抑制　　　　　　　　　　　　　　　
小野仁章, 梶原逸朗, 石塚真一
Dynamics and Design Conference 2005, 2005, Japanese, Oral presentation
[Domestic Conference]

スマート構造の実験的モデル化による振動・騒音のアクティブ制御　　　　　　　　　　　　　　　
宮下真明, 西留千晶, 梶原逸朗
第9回運動と振動の制御シンポジウム, 2005, Japanese, Oral presentation
[Domestic Conference]

Multidisciplinary Optimization of Smart Structure with Characteristic Variation for Vibration Suppression　　　　　　　　　　　　　　　
2004, Poster presentation

マイクロ飛行機のためのレーザー推進／追尾システム　　　　　　　　　　　　　　　
星野健太郎, 石川博康, 梶原逸朗, 嶋根義親, 矢部孝, 内田成明
第53回理論応用力学講演会, 2004, Japanese, Oral presentation
[Domestic Conference]

スマート構造におけるPZTアクチュエータと制御系の複合領域最適化　　　　　　　　　　　　　　　
大橋史武, 梶原逸朗
日本機械学会関東支部第10期総会講演会, 2004, Japanese, Oral presentation
[Domestic Conference]

パンタグラフ機構のスマート構造化による振動制御　　　　　　　　　　　　　　　
岩垂素子, 大橋史武, 土谷亮, 梶原逸朗, 堀江三喜男
日本機械学会関東支部第10期総会講演会, 2004, Japanese, Oral presentation
[Domestic Conference]

特性変化を伴うスマート構造の制振性能向上を目指した複合領域最適化　　　　　　　　　　　　　　　
土屋亮, 梶原逸朗
日本機械学会2004年度年次大会, 2004, Japanese, Oral presentation
[Domestic Conference]

スマートパンタグラフ機構におけるアクチュエータと制御の統合的最適化　　　　　　　　　　　　　　　
岩垂素子, 梶原逸朗, 堀江三喜男
Dynamics and Design Conference 2004, 2004, Japanese, Oral presentation
[Domestic Conference]

複合領域最適化によるレーザー推進マイクロ飛行機の設計　　　　　　　　　　　　　　　
梶原逸朗, 矢部孝
Dynamics and Design Conference 2004, 2004, Japanese, Oral presentation
[Domestic Conference]

アクチュエータアレイを用いたスマート構造の適応制御　　　　　　　　　　　　　　　
土屋亮, 梶原逸朗
Dynamics and Design Conference 2004, 2004, Japanese, Oral presentation
[Domestic Conference]

特性変動を有するスマート構造のアクチュエータ／スケジューリング制御の統合的最適化　　　　　　　　　　　　　　　
梶原逸朗, 大橋史武
第47回自動制御連合講演会, 2004, Japanese, Oral presentation
[Domestic Conference]

スマート構造におけるアクチュエータアレイと適応制御の統合的最適化　　　　　　　　　　　　　　　
土屋亮, 梶原逸朗
第6回最適化シンポジウム, 2004, Japanese, Oral presentation
[Domestic Conference]

GAによるスマート構造の圧電アクチュエータ配置と制御系の同時最適化　　　　　　　　　　　　　　　
岩垂素子, 大橋史武, 梶原逸朗
第8回日本計算工学会講演会, 2003, Japanese, Oral presentation
[Domestic Conference]

制御性を考慮したスマート構造の位相・形状最適化　　　　　　　　　　　　　　　
梶原逸朗, 大森隆広
Dynamics and Design Conference 2003, 2003, Japanese, Oral presentation
[Domestic Conference]

スマートキャリッジアームにおける圧電アクチュエータ配置と制御系の統合最適化　　　　　　　　　　　　　　　
大橋史武, 梶原逸朗, 有坂寿洋
Dynamics and Design Conference 2003, 2003, Japanese, Oral presentation
[Domestic Conference]

遺伝的アルゴリズムを用いたスマート構造の機構と制御の統合最適化　　　　　　　　　　　　　　　
岩垂素子, 大橋史武, 梶原逸朗
Dynamics and Design Conference 2003, 2003, Japanese, Oral presentation
[Domestic Conference]

レーザー推進マイクロ飛行機におけるレーザー追尾装置とスマート翼の開発　　　　　　　　　　　　　　　
石川博康, 梶原逸朗, 古谷俊輔, 矢部孝
Dynamics and Design Conference 2003, 2003, Japanese, Oral presentation
[Domestic Conference]

スマート構造における圧電アクチュエータとモード制御系の同時最適化による制振性能の向上　　　　　　　　　　　　　　　
梶原逸朗, 大橋史武
第8回運動と振動の制御シンポジウム, 2003, Japanese, Oral presentation
[Domestic Conference]

Hybrid Control of Motion and Vibration for Smart Flexible-Link Mechanism　　　　　　　　　　　　　　　
Nishidome, C, Kajiwara, I
SICE Annual Conference 2002, 2002, English, Oral presentation
[International presentation]

Design of Shape and Control System for Micro-Airplane Development　　　　　　　　　　　　　　　
Ishikawa, H, Kajiwara, I, Yabe, T
SICE Annual Conference 2002, 2002, English, Oral presentation
[International presentation]

スマート構造における機構と制御の同時最適設計 (多入力系における検討)　　　　　　　　　　　　　　　
梶原逸朗, 上原学, 大森隆広
Dynamics and Design Conference 2002, 2002, Japanese, Oral presentation
[Domestic Conference]

光ディスク装置における光ピックアップ構造の動解析と最適化　　　　　　　　　　　　　　　
大森隆広, 梶原逸朗, 松井勉
Dynamics and Design Conference 2002, 2002, Japanese, Oral presentation
[Domestic Conference]

スマート構造における機構系と制御系の同時最適化　　　　　　　　　　　　　　　
上原学, 梶原逸朗, 大森隆広
第7回振動と運動の制御シンポジウム, 2001, Japanese, Oral presentation
[Domestic Conference]

スマート化フレキシブルリンク機構における運動と振動の制御－機構の提案および多リンクの同時スマート化－　　　　　　　　　　　　　　　
西留千晶, 梶原逸朗, 太田俊輔
第7回振動と運動の制御シンポジウ, 2001, Japanese, Oral presentation
[Domestic Conference]

スマート構造における位相形状と制御系の統合最適設計　　　　　　　　　　　　　　　
大森隆広, 上原学, 梶原逸朗
Dynamics and Design Conference 2001, 2001, Japanese, Oral presentation
[Domestic Conference]

実験的モデル化と制御系設計の統合に関する基礎的研究　　　　　　　　　　　　　　　
梶原逸朗, 月成俊介, 吉村卓也
Dynamics and Design Conference 2001, 2001, Japanese, Oral presentation
[Domestic Conference]

圧電フィルムによるOA機器の計測と制御　　　　　　　　　　　　　　　
江連勝彦, 猿渡克巳, 梶原逸朗, 森厚夫
Dynamics and Design Conference 2001, 2001, Japanese, Oral presentation
[Domestic Conference]

スマート構造における計測と制御　　　　　　　　　　　　　　　
梶原逸朗, 上原学, 大森隆広
日本機械学会2001年度年次大会, 2001, Japanese, Oral presentation
[Domestic Conference]

スマート構造における圧電アクチュエータ形状と制御系の最適設計　　　　　　　　　　　　　　　
梶原逸朗, 上原学, 大森隆広
第11回設計工学・システム部門講演会, 2001, Japanese, Oral presentation
[Domestic Conference]

スマート構造における圧電アクチュエータの形状設計 (数値最適化と正実性評価によるアプローチ)　　　　　　　　　　　　　　　
梶原逸朗, 原辰次, 上原学, 山内浩和
第14回計算力学講演会, 2001, Japanese, Oral presentation
[Domestic Conference]

圧電フィルムを用いたスマート構造における形状と制御の統合設計　　　　　　　　　　　　　　　
梶原逸朗, 上原学, 長松昭男
日本機械学会2000年度年次大会, 2000, Japanese, Oral presentation
[Domestic Conference]

スマート化フレキシブルリンク機構における運動と振動の制御　　　　　　　　　　　　　　　
梶原逸朗, 榊原範人, 長松昭男
Dynamics and Design Conference 2000, 2000, Japanese, Oral presentation
[Domestic Conference]

Shape Optimization of Micro Air Vehicles Considering Stability and Controllability　　　　　　　　　　　　　　　
Kajiwara, I, Haftka, R. T
第48回理論応用力学講演会, 1999, English, Oral presentation
[Domestic Conference]

振動低減のための構造系と制御系の統合設計法　　　　　　　　　　　　　　　
梶原逸朗, 長松昭男
Dynamics and Design Conference ’99, 1999, Japanese, Oral presentation
[Domestic Conference]

フレキシブルリンク機構における振動と運動の制御　　　　　　　　　　　　　　　
榊原範人, 梶原逸朗, 長松昭男
1999年度システム部門講演, 1999, Japanese, Oral presentation
[Domestic Conference]

スマート構造における形状と制御の同時最適化　　　　　　　　　　　　　　　
梶原逸朗, 榊原範人, 長松昭男
1999年度システム部門講演, 1999, Japanese, Oral presentation
[Domestic Conference]

Simultaneous Optimum Design of Structure and Control System　　　　　　　　　　　　　　　
Kajiwara, I
計測自動制御学会第３７回学術講演会予稿集, 1998, English, Oral presentation
[Domestic Conference]

複数の制御音源を用いたモード解析に基づくフィードバック音響制御　　　　　　　　　　　　　　　
松永義弘, 小池関也, 下嶋浩, 梶原逸朗
Dynamics and Design Conference ’98, 1998, Japanese, Oral presentation
[Domestic Conference]

Simultaneous Optimum Design of Shape and Control System for Micro Air Vehicles　　　　　　　　　　　　　　　
Kajiwara, I, Haftka, R. T
第76期日本機械学会全国大会講演会, 1998, English, Oral presentation
[Domestic Conference]

モード解析による１次元ダクト音場のモデル化と能動的騒音制御　　　　　　　　　　　　　　　
梶原逸朗, 福田将直, 下嶋浩
日本機械学会第74期通常総会講演会, 1997, Japanese, Oral presentation
[Domestic Conference]

ゲインスケジューリングによる平面２自由度マニピュレータの位置と力の制御　　　　　　　　　　　　　　　
梶原逸朗, 山家勝裕, 下嶋浩
日本機械学会第74期通常総会講演会, 1997, Japanese, Oral presentation
[Domestic Conference]

自動車エンジンマウントの最適設計法（遺伝的アルゴリズムによる連続変数と離散変数の同時最適化）　　　　　　　　　　　　　　　
梶原逸朗, 鎌田慶宣, 長松昭男
Dynamics and Design Conference ’97, 1997, Japanese, Oral presentation
[Domestic Conference]

防振ハンドルの最適設計に関する研究　　　　　　　　　　　　　　　
Hyou Eiko, 背戸一登, 土井文夫
Dynamics and Design Conference ’97, 1997, Japanese, Oral presentation
[Domestic Conference]

位置決め制御機構における構造と制御の統合最適化　　　　　　　　　　　　　　　
梶原逸朗, 長松昭男, 関研一, 小谷雄司
日本機械学会第73期通常総会講演会, 1996, Japanese, Oral presentation
[Domestic Conference]

感度解析による構造系と振動制御系の統合最適設計（構造物形状とセンサー/アクチュエーター配置の最適化）　　　　　　　　　　　　　　　
梶原逸朗, 長松昭男, 松永義弘
Dynamics and Design Conference ’96, 1996, Japanese, Oral presentation
[Domestic Conference]

ERAに基づく実験的状態空間モデル化と制御系設計の統合　　　　　　　　　　　　　　　
郭中陽, 梶原逸朗, 長松昭男
日本機械学会第74期全国大会講演会, 1996, Japanese, Oral presentation
[Domestic Conference]

振動制御系における構造物形状とセンサー/アクチュエータ配置の統合最適化　　　　　　　　　　　　　　　
梶原逸朗, 長松昭男
第2回最適化シンポジウム, 1996, Japanese, Oral presentation
[Domestic Conference]

加振力の周波数応答特性を考慮した構造物の結合点の最適配置法　　　　　　　　　　　　　　　
河辺佳子, 吉田忍, 三枝省三, 梶原逸朗, 長松昭男
第2回最適化シンポジウム, 1996, Japanese, Oral presentation
[Domestic Conference]

遺伝的アルゴリズムを用いた構造系と 制御系の統合最適設計　　　　　　　　　　　　　　　
辻岡一明, 梶原逸朗, 浅井勝彦, 長松昭男
第44回応用力学連合講演会, 1995, Japanese, Oral presentation
[Domestic Conference]

振動問題における構造物の形状最適設計　　　　　　　　　　　　　　　
梶原逸朗, 河辺佳子, 吉田忍, 三枝省三, 長松昭男
第44回応用力学連合講演会, 1995, Japanese, Oral presentation
[Domestic Conference]

固有振動数を高める構造物の形状最適化手法　　　　　　　　　　　　　　　
河辺佳子, 吉田忍, 三枝省三, 梶原逸朗, 長松昭男
第44回応用力学連合講演会, 1995, Japanese, Oral presentation
[Domestic Conference]

モード解析を用いたトラックキャブの ロバスト振動制御　　　　　　　　　　　　　　　
曽根原努, 河合一男, 久保康丸, 梶原逸朗, 長松昭男
自動車技術会春季大会学術講演会, 1995, Japanese, Oral presentation
[Domestic Conference]

高周波遷移領域のおける振動評価　　　　　　　　　　　　　　　
梶原逸朗, 高橋直樹, 長松昭男
Dynamics and Design Conference ’95, 1995, Japanese, Oral presentation
[Domestic Conference]

遺伝的アルゴリズムによる構造物の位相形状最適化（計算効率の向上と実機構造の最適化）　　　　　　　　　　　　　　　
梶原逸朗, 佐々木康貴, 長松昭男
Dynamics and Design Conference ’95, 1995, Japanese, Oral presentation
[Domestic Conference]

振動問題における結合条件の感度解析　　　　　　　　　　　　　　　
河辺佳子, 吉田忍, 三枝省三, 梶原逸朗, 長松昭男
第8回計算力学講演会, 1995, Japanese, Oral presentation
[Domestic Conference]

遺伝的アルゴリズムを用いた構造系と 制御系の統合最適設計　　　　　　　　　　　　　　　
辻岡一明, 梶原逸朗, 浅井勝彦, 長松昭男
Dynamics and Design Conference ’94, 1994, Japanese, Oral presentation
[Domestic Conference]

振動問題における構造物の形状最適設計　　　　　　　　　　　　　　　
梶原逸朗, 河辺佳子, 吉田忍, 三枝省三, 長松昭男
Dynamics and Design Conference ’94, 1994, Japanese, Oral presentation
[Domestic Conference]

構造系と 制御系の同時最適設計　　　　　　　　　　　　　　　
辻岡一明, 梶原逸朗, 浅井勝彦, 長松昭男
日本機械学会第７１期全国大会講演論文集, 1993, Japanese, Oral presentation
[Domestic Conference]

構造系と出力フィードバック制御系の同時最適設計　　　　　　　　　　　　　　　
梶原逸朗, 辻岡一明, 長松昭男
第９回宇宙構造シンポジウム, 1993, Japanese, Oral presentation
[Domestic Conference]

感度解析による構造系と制御系の最適設計　　　　　　　　　　　　　　　
梶原逸朗, 長松昭男
システム最適化に関するシンポジウム, 1991, Japanese, Oral presentation
[Domestic Conference]

特性行列同定法に基づく最適制御系の設計法　　　　　　　　　　　　　　　
梶原逸朗, 長松昭男, 大熊政明, 稲垣亨
第２回運動と振動の制御シンポジウム, 1991, Japanese, Oral presentation
[Domestic Conference]

共振点と反共振点の感度を用いた構造物の最適化方法　　　　　　　　　　　　　　　
梶原逸朗
第１回環境工学総合シンポジウム講, 1991, Japanese, Oral presentation
[Domestic Conference]

共振点消去の方法と光サーボ系の最適設計　　　　　　　　　　　　　　　
梶原逸朗, 長松昭男, 背戸一登
第５回宇宙構造シンポジウム, 1989, Japanese, Oral presentation
[Domestic Conference]

Dynamic characteristic measurement and damage detection of integrated machine/building/infrastructure systems via laser-induced plasma excitation
Grant-in-Aid for Scientific Research
Apr. 2019 - Mar. 2022
KAJIWARA ITSURO
A monitoring system for concrete hardening using laser excitation/measurement was developed in this study. Aluminum (Al) beam inserted in mortar was used as measurement object. Laser beam was irradiated to the Al beam to excite the vibration due to laser ablation and its frequency spectra were measured. It was confirmed that the characteristics on the resonance frequency and damping of the Al beam change as the mortar hardens over time. Moreover, it was found by the finite element analysis that there is a relationship between the hardness of the mortar and the natural frequency of the Al beam inserted in the mortar. By comparing the theoretically calculated frequency with the experimental result, the elastic modulus of the mortar and its variation with time could be estimated. The effectiveness of the developed monitoring system for concrete hardening was verified by some experiments.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, Principal investigator, Competitive research funding, 19H02088

A study on simple origami designs for 3D origami printer system and its origami robot
Grants-in-Aid for Scientific Research
Apr. 2015 - Mar. 2018
Hagiwara Ichiro
In this study, we showed a specification of origami robot with two arms which can fold stiff material. At ASME 2016 Student Mechanism & Robotics Design Competition, one of his students received the Third Place Award by achieving to fold a paper bag by his Lego-based robot. To make origami by origami robot, we needed to solve two problems: to obtain a general rule on robot friendly structures and to get robust control logic. We have overcome the problems and realized the origami robot. It been said that making origami such as current trend biomimetic origami or one-generation-ago origami like “crane” by robot was a big challenge. We developed the way to acquire robot friendly structures by arranging 2D plans and adding appropriate cuts on the plans, then glue on their margins. With this method, the Lego-based origami robot has achieved to make origami.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Meiji University, Coinvestigator, 15H02228

Dynamic characteristic evaluation and diagnosis of mechanical / biological systems by the non-contact laser vibrating system　　　　　　　　　　　　　　　
Grant-in-Aid for Scientific Research
2016 - 2018
KAJIWARA ITSURO
Principal investigator, Competitive research funding

Lamb wave generation to detect damage for a wide area of an aircraft using laser-induced plasma
Grants-in-Aid for Scientific Research
Apr. 2014 - Mar. 2017
Hosoya Naoki, Kanda Atsushi
This study aims to realize a non-contact damage detection system for large objects such as an aircraft. Irradiating the target surface with a high-power Nd: YAG pulse laser induces LA and generates Lamb waves. Spectrum analyses on the Lamb waves generated by LA reveal that the Lamb waves contain a broad range of frequency components up to several hundred kHz. The LA-generated Lamb waves have amplitudes several hundred times larger than those generated by conventional laser ultrasonic Lamb waves, improving the SN ratio. The improved SN ratio reduces the required number of measurements, resulting in a shorter measurement time. Thus, the proposed method can be applied to detect damage on a large area of a large structure. The LA-generated Lamb waves were applied to detect a through crack, which was artificially made to simulate damage. Damage causes the reflection and amplitude of the Lamb wave to change, demonstrating the effectiveness of LA-generated Lamb waves to detect damage.
Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, Shibaura Institute of Technology, Coinvestigator, 26630080

Acoustic Tests in a Micro Space based on a Point Source Generated by Laser-Induced Breakdown
Grants-in-Aid for Scientific Research
Apr. 2012 - Mar. 2014
HOSOYA Naoki, KAJIWARA Itsuro
This paper proposes a method of acoustic vibration testing based on a point source generated by laser-induced breakdown in the air. A high-power Nd: YAG pulse laser is used in this system for generating the laser-induced breakdown in acoustic fields. Plasma formation can be realized by the laser-induced breakdown if the local intensity of the laser beam reaches 1e+15 W/m2. The shock wave that is yielded by consuming a part of the plasma energy becomes a sound source. Assuming that the laser beam is focused to a small volume through a convex lens and the sound source by the laser induced-breakdown has nondirectional property, it is possible to create a point source with this technique. Securing the laser light path installs no device for acoustic excitation in acoustic fields. The system is validated by comparing the resonant frequencies of a micro-space measured by the laser-induced breakdown and calculated by theoretical model.
Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, Shibaura Institute of Technology, Coinvestigator, 24656158

Development of High Frequency Vibration Measurement and Health Monitoring System Using Contactless Laser Excitation
Grant-in-Aid for Scientific Research
2010 - 2012
KAJIWARA ITSURO
This study developed a vibration testing and health monitoring system based on an impulse response excited by a laser ablation. High power Nd: YAG pulse laser was used for producing an ideal impulse force on structural surface. It was possible to measure high frequency vibration responses in this system. A health monitoring system was constructed by this vibration testing system and a damage detecting algorithm.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hokkaido University, Principal investigator, Competitive research funding, 22246027

Research on Creating Function of New Lightweight Core Structure and Its Forming Method by Fusion of Computational Mechanics and Origami Engineering
Grants-in-Aid for Scientific Research
2008 - 2012
HAGIWARA Ichiro, SUGIYAMA Fumiko, KOZUKUE Wakae, ZHAO Xilu, NOJIMA Taketoshi, YASUI Takeo, KITAOKA Tetsuko, OSHIMA Shuzo, OOKUMA Masaaki, FUKUSHIMA Naoto, SHINODA Junichi
The forming method of truss core developed by space filling geometry and Origami operation was established, and its application to industry proved that truss core is superior totally to honey comb. The forming method of reverse spiral cylindrical Origami structure as deployable and foldable core was developed, and it was shown that the structure could be excellent energy absorption. Mapping transformation made the range of industry application widen, because it could generate efficiently the complicated folding structures. Finally, Origami theory is applied to generate real copy model which could become the spout of new industry.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (S), Coinvestigator, 20226006

Design of vibration mode shape for composite piezoelectric material by using local anisotropy
Grants-in-Aid for Scientific Research
2010 - 2011
HONDA Shinya, NARITA Yoshihiro, KAJIWARA Itsuro
The present study generated a new function of carbon fiber reinforced laminated materials, known as advanced composite materials with high specific stiffness and strength. New structures of composite materials with curvilinear reinforcement fibers and variable-thicknesses were proposed in this study, and this structure realized local anisotropy in different positions of structures. Optimum placements of local anisotropy induced by optimum curvilinear fiber shape and distributed thickness resulted in controlling shapes of vibration mode arbitrary. The technique was applied to design optimum smart composite structures to enhance the performances of vibration suppression. From above, it is concluded that the present technique enables effective usage or suppression of vibration by considering the shape of vibration mode.
Japan Society for the Promotion of Science, Grant-in-Aid for Young Scientists (B), Hokkaido University, Coinvestigator, 22760164

Innovative vibration test method based on noncontact excitation via laser ablation　　　　　　　　　　　　　　　
JST A-STEP (Feasibility Study)
2009 - 2010
KAJIWARA ITSURO
Principal investigator, Competitive research funding

Develoment of large capacity hard disk drive using smart structure techonogies　　　　　　　　　　　　　　　
JST SEEDS TEST (B)
2008 - 2008
KAJIWARA ITSURO
Principal investigator, Competitive research funding

Develoment of large capacity hard disk drive using smart structure techonogies　　　　　　　　　　　　　　　
JST SEEDS TEST
2007 - 2007
KAJIWARA ITSURO
Principal investigator, Competitive research funding

Remote Control of Micro-Vehicles with Laser and Micro-Optics System
Grant-in-Aid for Scientific Research
2006 - 2007
KAJIWARA ITSURO
This study presents the development of the integrated laser tracking/control/energy transmission system. First, the LPFM laser control approach for laser-driven micro-vehicles is proposed and the integrated laser tracking/control system is developed. The laser control system is a key technology to achieve remote control of laser-driven micro-vehicles. With the LPFM laser control, both long-distance remote control and high-speed positioning are achieved since laser performs long-distance transmission and the output is rapidly variable. In addition, communication using laser beam can make a resolution to prevent interference and tapping unlike radio communication. In order to integrate each system on the laser tracking and control, both laser tracking/control systems and dielectric mirrors are synthesized in the total system. Next, the constitution and function of LPFM laser control of laser-driven micro-vehicle is shown and a fundamental experiment of LPFM laser control is conducted. Furthermore, experiments with a miniature vehicle are carried out to confirm the performance of the developed system. Finally, the integrated laser tracking/control/energy transmission system is developed by synthesizing the integrated laser tracking/control system and a laser energy transmission system. The purpose of the energy transmission system is to transmit energy to the micro-vehicle with high-power laser and to drive it. Solar cell is used as the photoelectric conversion element. The optical system is constructed by some dielectric mirrors to integrate two systems without interference. The fundamental system is developed and its performance is evaluated throughout the experiment.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Tokyo Institute of Technology, Principal investigator, Competitive research funding, 18560225

Multidisciplinary Design Optimization of Structure/Fluid/Control and Application for Micro-Air Vehicle Development
Grant-in-Aid for Scientific Research
2002 - 2004
KAJIWARA ITSURO
A multidisciplinary design optimization method of Structure/Fluid/Control has been proposed to achieve the required performance of advanced mechanical system. An approach for optimization technology of the placement of the piezoelectric actuators and the control system in smart structures has been developed to improve the vibration control performance. The modeling approach based on FEA and modal analysis is appropriate to obtain the reduced-order system which is used for designing the control system. The optimal placement of the piezoelectric actuators and control system have been simultaneously designed by the presented two-step procedure with GA. The proposed method is applied to designing some mechanical systems to evaluate the effectiveness of the method. It has been verified from this study that the complexity of the optimization algorithm and the calculation efficiency are significantly improved and the enhanced control performance can be achieved by the proposed multidisciplinary design optimization method. Next, the laser tacking system and the integrated laser propulsion/tracking system have been designed and developed as elemental and key technologies for realizing an actual flight and control of the laser-driven micro-airplane. First, the characteristics and the performance of the developed laser tracking system composed of the He-Ne laser, condenser, beamsplitter, PSD and galvano-mirror have been evaluated by the experiment. It has been verified that the laser is traced to the moving reflector with the required accuracy in this system. Next, the integrated laser propulsion/tracking system has been developed with the laser tracking system, the YAG laser and the optical system. It has been verified that the repetitive ablation on the moving target has been caused by the developed laser propulsion/tracking system that is available to achieve the continuous flight and control of the laser-driven micro-airplane.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Tokyo Institute of Technology, Principal investigator, Competitive research funding, 14350118

Development of evolutionary structural optimization design under kinematics and control system
Grants-in-Aid for Scientific Research
2001 - 2003
OKUMA Masanki, NAKAHARA Takeshi, TAMURA Shinji, KAJIWARA Itsuro
The purpose of this research is to develop a new evolutionary structural optimization design methods under kinematics and control system and, in addition, to investigate the structural advanced feature of dragonflies from the viewpoint of structural dynamics. New evolutionary structural optimization methods for static and dynamics have been developed. Then, their advantages and practical usefulness have been investigated using some kinds of basic application studies. This research has published some valuable technical papers and reports and has eventually obtained a ph.D degree to a graduate student of ph.D course who contributed to this research project The dependency problem of initial structures was deeply investigated and was made weak to optimum solutions. This investigation invented the new evolutionary structural optimization. Therefore, the method steadily creates very good results. A cantilever model, a bridge model and a connecting rod in engine etc. were optimally designed by the methods and their good results were obtained. In addition, a health monitoring system is developed as a kind of artificial nerve system for mechanical structural systems. Because the structures to be designed by such evolutionary optimization methods should be implemented such self-monitoring systems. Very precise investigation of dragonfly wings was carried out from the viewpoint of str-uctural dynamics. Vibration testing gave the fundamental natural frequencies and natural modes of the wings. Vein network pattern was accurately measured using a digital microscope and a finite element model of a dragonfly wing was created. The finite element model is available for various computer simulation studies. Finally, the result of this research will be able to create the possibility and usefulness of future development on this sort of research works to the investigators and others
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Tokyo Institute of Technology, Coinvestigator, 13450091

Development of laser propulsion micro airplane by integrated optimal design of the structure / fluid / control
Grant-in-Aid for Scientific Research
2002 - 2002
KAJIWARA ITSURO
レーザーにより推進力を発生させるメカニズムを応用したマイクロ飛行機の開発に向け,それを実現するためのレーザー推進メカニズムの解明,ならびにレーザー追尾システムおよびスマート翼の開発を行った.本研究で開発したレーザー追尾システムは,レーザー偏光ビームスピリッタ,ガルバノミラーおよび光検出器により構成される.計測原理は,レーザー光がガルバノミラーを経由してマイクロ飛行機のリフレクターに照射され,その反射光がガルバノミラーを経て偏光ビームスピリッタにより光検出器へと導かれ,ここで位置誤差に関する信号検出が行われる.ここで,ガルバノミラーは,DCモーターにより縦・横方向に回転できる機構になっており,光検出器からの信号よりディジタル制御システムにより制御入力が演算され,それによってガルバノミラーを回転させることにより,レーザーを目標に追尾させる.制御手法としては,PID制御および混合H_2/H_∞制御を検討したが,両者とも優れた制御性能を示した.次に,マイクロ飛行機の小型化・軽量化を行いながら飛行制御を実現するために,アクチュエータとして形状記憶合金(SMA)を採用し,フォトトランジスタをスイッチング素子として利用した光学系を導入することにより,外部からのレーザー照射によって遠隔制御可能なスマート翼を開発した.翼に入射したレーザーはビームスプリッタによってコーナーキューブリフレクターとフォトトランジスタに入射する.リフレクターに入射したレーザーは前述のレーザー追尾に使用され,フォトトランジスタに入射するレーザーは翼の制御に使用される.フォトトランジスタはSMAへの電圧印加のスイッチとして機能し,レーザーが入射している間,電圧が印加されSMAが変形する.レーザーのオン・オフによる制御実験を行ったところ,SMAの応答性の範囲内で目標値に対する良好な追従性能が達成された.
日本学術振興会, 萌芽研究, 東京工業大学, Principal investigator, Competitive research funding, 14655091

Integration design method of structure and control system in smart structures
Grant-in-Aid for Scientific Research
2000 - 2001
KAJIWARA ITSURO
本研究では,振動制御の機構としてスマート構造を用い,諸性能の向上を達成すべく,アクチュエータ形状/配置と制御の同時設計方法を提案・開発した.同時に,有限要素法(FEM)とモード解析法に基づく低次元モデル化法およびモード制御法を示し,実験による検証を行った.アクチュエータの適切な形状/配置を決定することは,少ない制御エネルギーで高い制振効果を得るために重要なことであり,アクチュエータ形状を含めた機構設計と制御系設計を融合する意義は大きく,高性能化の達成が期待できる.スマート化の基礎となるアクチュエータおよびセンサを圧電フィルムにより構成した.圧電フィルムは非常に軽薄な高分子材料であるため,取り付けが容易であり,柔軟構造のスマート化に適している.固定部を要しないセンサとして,圧電フィルムの他に加速度センサを用いる場合についても検討した.圧電アクチュエータの形状に関する設計変数を,制御対象のFEMモデルに対応する圧電フィルムの幅,配置に関する設計変数をFEMモデルの節点番号とした.H_2性能の向上を目指した設計問題を定義し,圧電フイルムアクチュエータの形状/配置と制御系を同時に最適化した.最適化手法としては,圧電アクチュエータ形状を設計変数とする場合は逐次二次計画法,配置を設計変数とする場合は遺伝的アルゴリズム(GA)を用いた.シミュレーションおよび実験を行い,達成される振動抑制効果および同時最適化の有効性を評価した.さらに,提案した圧電アクチュエータ配置と制御系の同時最適設計法を磁気ディスクアームの制振設計に応用し,その有効性および実用性を検証した.
日本学術振興会, 奨励研究(A), 東京工業大学, Principal investigator, Competitive research funding, 12750178

線形行列不等式に基づく構造系と制御系の統合最適設計法の構築と実用化
科学研究費助成事業
1998 - 1999
梶原 逸朗
先端情報機器に要求される諸性能の向上を目指し、スマート構造を利用した知的構造物における形状と制御の統合最適化方法を、非線形最適化法と線形行列不等式に基づいて構築した。スマート化構造物には、それ自身にセンサー/アクチュエータ機能を有しており、構造形状を含めた機構設計と制御系設計を融合する意義は大きく、高性能化を達成できることを明らかにした。本研究では、制御性を考慮した構造設計および同時最適設計の両面から適切な問題設定について考察し、達成される性能および両者の得失を評価した。また、フレキシブルリンク機構を対象とし、スマート構造を導入した機構と制御の最適化を図り、達成される高速位置決めと振動制御の性能評価および検証を行った。統合設計における構造系の設計変数としては、対象とする構造の形状、寸法とした。制御方法は、周波数領域および時間領域の設計を包括的に扱うことができる線形行列不等式に基づく方法を採用した。すなわち、制御性能の指標として、システム方程式における外乱から制御量までのH_2ノルム、さらにロバスト安定性に関しては伝達関数行列のH_∞ノルムを採用し、要求される諸性能を線形行列不等式により統合的に記述する。そして、構造系に要求される小型化・軽量化を最適化問題の中に導入する。構造系と制御系の各特性、および統合系としての諸性能を用いて、統合最適化問題を定義する。この問題を、逐次二次計画法とLMIソルバーを結合したアルゴリズムにより解き、最適な構造系と制御系と同時に決定する手法を提案・構築した。そして、動的シミュレーションおよび実験により、提案したモデル化手法と統合設計法の有効性を実証した。
日本学術振興会, 奨励研究(A), 東京工業大学, 10750166

線形行列不等式に基づく構造系と制御系の統合最適設計法の構築と実用化
科学研究費助成事業
1997 - 1997
梶原 逸朗
日本学術振興会, 奨励研究(A), 東京工業大学, Principal investigator, 09750252

Integrated Optimum Design of Structure and Servosystem in Information Processing Equipments
Grants-in-Aid for Scientific Research
1996 - 1996
NAGAMATSU Akio, TSUJIOKA Kazuaki, KAJIWARA Itsuro, OKUMA Masaaki
This study presents approaches for optimum design of structure and servosystem to realize higher performances concerning the positioning and the stability. The proposed approaches use the sensitivity analysis and the nonlinear programming method, in which the integrated optimum design of structure and servosystem is taken into consideration. The performance specifications of the control system are generally expressed as the cahracteristics on frequency and time domains Therefore, this study considers two types of the servosystem, namely one is composed of dynamic compensator such as phase-lead and phase-lag compensators in order to deal with the desired frequency characteristics, and the other is composed of LQI control system in which the controller is desighed to achieve the desired transient responses. The original spatial model of a structure with large degrees of freedom (DOF) is made by the finite element method (FEM). The perfomances and the stability of the servosystem depend on the structural characteristics such as the gain and the phase properties of frequency response function (FRF) between the control input and the output signals. Higher performances of the servo properties and stability of the closed-loop system against the high order natural modes are achieved by the integrated optimization presented in this study. Two modal models are made from the original spatial model, namely one is the reduced modal odel of small DOF and the other is the original modal model of medium DOF.The properties of the servosystem composed of the reduced modal model are optimized under the constranit that the closed-loop system composed of the original modal model must be stable. Effectiveness and practicability of the approaches are verified with a simplified model structure of a positioning device.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Tokyo Institute of Technology, Coinvestigator, 08455111

Enhancement of time/frequency domain performance of information devices via integrated optimization
Grant-in-Aid for Scientific Research
1996 - 1996
KAJIWARA ITSURO
構造物の動特性の性能向上を図るために、トポロジを考慮した任意形状最適化を可能にする構造最適設計法を開発した.本手法では、設計変数としてFEM要素の板厚、節点座標および要素の有無を採用している.最適化手法として遺伝的アルゴリズムを用いることにより、これらの設計変数の最適化を実現している.そして、時間領域特性と周波数領域特性を考慮した制御系の最適化手法を開発した.周波数領域の制御方法として、位相補償による動的補償器を用いて高次モードの安定性を保ちながら追従誤差を最小にする制御系設計法を提案した.次に、時間領域の制御方法として、LQI制御理論を用いた制御系設計法を開発することにより、アクセス時間の短縮を実現する最適設計を可能にした.ここで、設計変数としては動的補償器のパラメーター、LQI理論における重み係数行列とした.
さらに、アクセスサーボの高性能化を実現するために、構造系と制御系の統合最適設計法の開発を行った.本手法では、サーボ系のループゲイン、アクセス時間、構造系の不確定性に対するロバスト性能、構造系の質量および形状を用いて最適化における目的関数および制約条件を定義している.そして、要求される設計仕様を含めて統合最適化問題の設定を行い、構造系と制御系の両設計変数に関する感度解析手法を確立させ、実現可能な性能とそのときの最適な両設計変数を決定する手法の開発およびプログラミングを行った.最適化手法としては、逐次二次計画法および遺伝的アルゴリズムを用い、連続設計変数と離散設計変数の同時最適化、ならびに大域的な最適解の探索を可能にしている。
上述の方法を用いて、位置決め制御機構の設計および試作を行い、シミュレーションおよび実験により提案手法の有効性を検証した.
日本学術振興会, 奨励研究(A), 東京工業大学, Principal investigator, Competitive research funding, 08750265

構造系と制御系の統合最適設計による情報機器の追従制御機構の性能向上
科学研究費助成事業
1995 - 1995
長松 昭男, 辻岡 一明, 梶原 逸朗, 大熊 政明
振動制御系と位置決め制御機構の高性能化を達成するために、構造系と制御系の統合設計法の提案および開発を行った。本方法は、遺伝的アルゴリズムと感度解析法を用いた非線形計画法に基づいており、制御性を考慮した構造最適化および構造系と制御系の統合最適化の両方を実行可能である。構造系と振動制御系の統合最適化では、制御系としてH^∞制御系を採用し、遺伝的アルゴリズムを用いて構造物形状と制御則、さらにセンサーおよびアクチュエーターの配置最適化を行うことにより、高性能な周波数整形を可能にした。構造系とサーボ系の統合最適化では、周波数領域と時間領域の性能に対応するために2種類のサーボ系を導入した。すなわち、1入出力系に対して用いられる動的補償器と、多入力系に対して設計されるLQI制御系である。サーボ性を考慮した構造最適化では、制御対象の固有振動数と固有モードをサーボに適した周波数応答が実現されるように最適化する方法を開発した。構造系と動的補償器の統合最適化では、着目する全てのモードの安定性を維持しながら、サーボ性能を左右する主要な極の配置を最適化し、閉ループ系に要求される周波数特性を達成することを可能にした。構造系とLQI制御系の統合最適化では、閉ループ系の安定性を維持しながら、目標入力に対する時間領域での高速追従性能を実現した。本研究で提案・開発した方法を簡易構造の位置決めデバイスの統合設計に適用し、その有効性と実用性を検証している。
日本学術振興会, 一般研究(B), 東京工業大学, 07455102

Integrated Optimum Design of Structure and Servosystem in Information Processing Devices
Grant-in-Aid for Scientific Research
1995 - 1995
KAJIWARA ITSURO
情報機器が内蔵する位置決め制御機構の高性能化を達成するために、構造系と制御系の統合設計法の提案および開発を行った。本方法は、遺伝的アルゴリズムと感度解析法を用いた非線形計画法に基づいており、制御性を考慮した構造最適化および構造系と制御系の統合最適化の両方を実行可能である。まず、位置決め時に構造系が発生する残留振動により追従性能が劣化するのを防止するために、構造系とH^∞制御系の統合最適設計法を開発した。ここでは、遺伝的アルゴリズムを用いて構造物形状と制御則、さらにセンサーおよびアクチュエーターの配置最適化を行うことにより、高性能な周波数整形を可能にし、位置決め制御系における残留振動問題を改善した。構造系とサーボ系の統合最適化では、周波数領域と時間領域の性能に対応するために2種類のサーボ系を導入した。すなわち、1入出力系に対して用いられる動的補償器と、多入力系に対して設計されるLQI制御系である。サーボ性を考慮した構造最適化では、制御対象の固有振動数と固有モードをサーボに適した周波数応答が実現されるように最適化する方法を開発した。構造系と動的補償器の統合最適化では、着目する全てのモードの安定性を維持しながら、サーボ性能を左右する主要な極の配置を最適化し、閉ループ系に要求される周波数特性を達成することを可能にした。構造系とLQI制御系の統合最適化では、閉ループ系の安定性を維持しながら、目標入力に対する時間領域での高速追従性能を実現した。本方法を簡易構造の位置決めデバイスの開発に適用した結果、手法の有効性と実用性が確認された。
日本学術振興会, 奨励研究(A), 東京工業大学, Principal investigator, Competitive research funding, 07750255

High-speed positioning of auto-focus mechanism via optimization
Grant-in-Aid for Scientific Research
1994 - 1994
KAJIWARA ITSURO
本研究では、まずサーボ性を考慮した構造系の最適化を感度解析により実行する方法を提案している。この最適化方法により、サーボ性能と安定性を向上させるための構造物の固有振動数と固有モードの最適化を可能にした。そして、感度解析を用いた構造系とサーボ系の統合最適設計法の提案および開発を行った。この方法は、構造系の形状、制御系の比例ゲインおよび動的補償器のパラメータを設計変数とし、サーボ性能を向上させるための各設計変数の最適値を決定するものである。これらの方法を用いて、位置決め制御機構の簡易モデルの最適設計および実験を行うことにより、手法の有効性を検証している。
次に、高性能な周波数応答の整形を実現させるために、構造系とH^∞制御系の統合設計手法の開発を行った。まず、コンプレックス法による構造系とH^∞制御系の統合設計法の提案および開発を行い、さらにセンサー、アクチュエータ配置を含めた統合設計手法の開発を行っている。後者の方法では、最適化手法として遺伝的アルゴリズムを用いることにより、設計変数が離散値となるセンサー、アクチュエータ配置の最適化を可能にし、構造系との連携においてより自由度の高い設計を行うことを可能にしている。さらに、動的補償器の次数を増やさずに複数のモードの制振を行える、モード重み係数を用いたH^∞制御系の設計法を提案し、その実用性を検証している。
日本学術振興会, 奨励研究(A), 東京工業大学, Principal investigator, Competitive research funding, 06750226

DEVELOPMENT AND PRACTICE OF SIMULTANEOUS OPTIMUM DESIGN OF STRUCTURE AND CONTROL SYSTEM
Grants-in-Aid for Scientific Research
1993 - 1994
NAGAMATSU Akio, YAMAGUCHI Masakatsu, KAJIWARA Itsuro, OKUMA Masaaki
This study proposes new optimum design methods of structure and control system. Forst, a structural topology optimization method based on the genetic argorithm is presented. The fitness function composed of a natural frequency is maximized by optimizing the topology of the structure. The optimum topology of the structure is determined by optimizing the placement of the finite elements in FEM analysis. In the optimum design based on the genetic argorithm, the computer burden should be decreased for practical use. This study improves the genetic operations with respect to the crossover and the mutation in order to improve the efficiency of the calculation. Furthermore, the higher efficiency of the calculation is achieved by the model reduction in structural analysis. Effectiveness and practicability of the proposed approach are verified by optimizing the topology of the guide-arm installed in the magnetic disk device. Next, this study proposes a sumultaneous optimum design method of structure and control system by which to design an optimum servosystem composed of continuous body structures using modal analysis and sensitivity analysis. The mechanical structures is modeled first by FEM.This spatial model are of such high degree of freedom that a control system cannot be designed. This spatial model is transformed into a modal model in order to reduce DOF.The servosystem is composed with the reduced model and a dynamic compensator. However, stability of the control system is not always guaranteed because the modal model ignores high-order modes. An simultaneous optimization method of the structure and the control system which guarantees stability of the actual system is proposed in this study. The optimization is performed using sensitivity analysis and nonlinear programming. The effectiveness of the proposed method is verified by both simulation and experiment.
Japan Society for the Promotion of Science, Grant-in-Aid for General Scientific Research (A), Tokyo Institute of Technology, Coinvestigator, 05402034

Vibration control of vehicle system via simultaneous optimization of structure and control system
Grant-in-Aid for Scientific Research
1993 - 1993
KAJIWARA ITSURO
構造系とH^∞制御系の同時最適設計を、モード解析とコンプレックス法により実行する方法を提案した。構造系のモデル化には有限要素法を適用し、モード座標に変換することによりシステムの低次元化を行い、これに対しH^∞制御系を設定する。そして、構造系とH^∞制御系を同時に最適化することにより、閉ループ系の周波数特性の高性能化とロバスト安定性の向上を実現させる。本研究で設定した同時最適化問題では、外乱から制御量までのH^∞ノルムを目的関数として採用している。また、設計変数としては構造物の寸法と目的関数でもあるH^∞ノルムを同時に採用する。このとき、目的関数は設計変数に対して不連続関数となり、目的関数の感度を用いて設計変数の最適解を探索する通常の最適化手法は適用できない。そこで、ランダム探索法の一つであり、目的関数の感度を用いずに設計変数の最適解を探索するコンプレックス法を用いることにより、同時最適化を可能にしている。また、構造系の質量を最適化問題に導入することにより、制御性能と質量のバランスのとれた設計を実現している。提案する方法を基礎モデルで構成される振動制御系の同時最適化に適用したところ、周波数応答特性の最適化が実現され、本手法の有効性を実証している。
日本学術振興会, 奨励研究(A), 東京工業大学, Principal investigator, Competitive research funding, 05750213

Robust control of optical head actuator via simultaneous optimization of structure and control system
Grant-in-Aid for Scientific Research
1992 - 1992
KAJIWARA ITSURO
日本学術振興会, 奨励研究(A), 東京工業大学, Principal investigator, Competitive research funding, 04750193

Design of an Optical Servosystem using a Simultaneous Optimization of Structure and Control System
Grants-in-Aid for Scientific Research
1991 - 1992
NAGAMATSU Akio, YAMAGUCHI Masakatsu, KAJIWARA Itsuro, OKUMA Masaaki
This study proposes a new design concept that takes into consideration the construction of a mechanism that consists of a structural system and a control system. Firstly, a method for structural dynamic optimization is proposed using sensitivity analysis of resonance and anti-resonance frequencies. The sensitivity of the anti-resonance frequency is newly defined. An approach for eliminating the resonance peak from the frequency response function (FRF) is proposed using this sensitivity, modifying both the frequencies of this resonance and the neighboring anti-resonance bottom to the same value. Optimum design of an optical actuator for a compact disk player is performed practically by eliminating resonance peaks which deteriorates its servo control function. The player, with this optimized actuator, shows an excellent performance of sound playback. Next, an approach is presented for simultaneous optimum design of structure and control system. The design variables of both structure and control parameters are optimized simultaneously by the sensitivity analysis in order to minimize the response dur to disturbances of both white noise and colored noise under the constraining condition that the system is stable against high order natural modes. Three kinds of model are adopted in this approach, namely the original spatial model by FEM, the reduced modal model for designing control system and the original modal model for assuring stability of the system. Validity and usefulness of the presented approach are verified by an experiment of vibration control with a steel plate.
Japan Society for the Promotion of Science, Grant-in-Aid for General Scientific Research (B), Tokyo Institute of Technology, Coinvestigator, 03452139

Automotive vibration suppression via simultaneous optimization of structure and control system
Grant-in-Aid for Scientific Research
1991 - 1991
KAJIWARA ITSURO
日本学術振興会, 奨励研究(A), 東京工業大学, Principal investigator, Competitive research funding, 03750165

硬化体解析方法、硬化体解析システム、硬化体解析装置、及び硬化体解析プログラム　　　　　　　　　　　　　　　
Patent right, 竹本喜昭, 齊藤亮介, 梶原逸朗, 北海道大学
特願2019-149080, 19 Oct. 2020
特許7486745, 10 May 2024
竹本喜昭;齊藤亮介;梶原逸朗

構造物の振動特性の測定方法及び構造物の振動特性の測定装置　　　　　　　　　　　　　　　
Patent right, 齊藤亮介, 梶原逸朗, 北垣亮馬, 北海道大学
15 Aug. 2019
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齊藤亮介;梶原逸朗;北垣亮馬

振動特性計測用の発射装置、加振力入力具、振動特性計測システム及び振動特性計測方法　　　　　　　　　　　　　　　
Patent right, 細矢直基, 梶原逸朗
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細矢直基;梶原逸朗

Method for Measurement of Vibration Property of Structure, and Vibration Property Measurement Device　　　　　　　　　　　　　　　
Patent right, Kajiwara, I, Hosoya, N
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Active vibration control device and design method therefor　　　　　　　　　　　　　　　
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能動型防振装置及び能動型防振方法　　　　　　　　　　　　　　　
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能動型防振装置　　　　　　　　　　　　　　　
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Method for Measurement of Vibration Property of Structure, and Vibration Property Measurement Device　　　　　　　　　　　　　　　
Patent right, Kajiwara, I, Hosoya, N
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MRE用の加振装置、加振システム、および加振方法　　　　　　　　　　　　　　　
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構造物の振動特性の測定方法および振動特性測定装置　　　　　　　　　　　　　　　
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内燃機関の制御方法及び制御装置　　　　　　　　　　　　　　　
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振動低減装置のコントローラの設計法、振動低減装置のコントローラ及び振動低減装置　　　　　　　　　　　　　　　
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