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Last Updated :2024/11/07

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Master

Affiliation (Master)

  • Faculty of Engineering　Mechanical and Aerospace Engineering　Human and Mechanical Systems

Affiliation (Master)

  • Faculty of Engineering　Mechanical and Aerospace Engineering　Human and Mechanical Systems

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Profile and Settings

Profile and Settings

  • Name (Japanese)

    ITSURO

  • Name (Kana)

    KAJIWARA

  • Name

    200901087870258131

Alternate Names

Achievement

Research Interests

  • 産業応用   構造ヘルスモニタリング   レーザー工学   スマート構造   制御   振動   構造動力学   Structural dynamics   

Research Areas

  • Informatics / Mechanics and mechatronics

Research Experience

  • 2009/04 - Today Hokkaido University Graduate School of Engineering Professor
  • 2000/04 - 2009/03 Tokyo Institute of Technology Graduate School of Science and Engineering Associate Professor
  • 1990/04 - 2000/03 Tokyo Institute of Technology Faculty of Engineering Assistant Professor

Education

  • 1986/04 - 1988/03  東京工業大学大学院
  •        - 1988  Tokyo Institute of Technology  Graduate School, Division of Science and Engineering
  •        - 1986/03  Tokyo Metropolitan University  Faculty of Engineering  Department of Mechanical Engineering

Committee Memberships

  • -2024/06   International Conference: Innovation in Engineering (ICIE’2024) (June 26-28, Science and Technology Park, Portugal)   International Scientific Committee
  • 2022   The 10th International Conference on Control, Mechatronics and Automation (ICCMA 2022), (University of Luxembourg, Luxembourg),   International Technical Committee
  • 2005   'International Journal of Vehicle Design'   Guest Editor

Awards

  • 2023/08 日本機械学会 機械力学・計測制御部門 学術業績賞
     
    受賞者: 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
     
    受賞者: 梶原 逸朗
  • 2017 日本機械学会 120周年記念功労者表彰
     
    受賞者: 梶原 逸朗
  • 2016 可視化情報学会賞 技術賞
     
    受賞者: 梶原 逸朗
  • 2015 日本機械学会 論文賞
     
    受賞者: 梶原 逸朗
  • 2010 情報ストレージ研究推進機構 論文賞
     
    受賞者: 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
     
    受賞者: 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
     
    受賞者: 梶原 逸朗
  • 1989 日本機械学会 論文賞
     
    受賞者: 梶原 逸朗
  • 1984 日本機械学会 畠山賞
     
    受賞者: 梶原 逸朗

Published Papers

  • Qi Liu, Hong Lu, Heisei Yonezawa, Ansei Yonezawa, Itsuro Kajiwara, Tao Jiang, Jiji He
    Mechanical Systems and Signal Processing 224 (112041) 1 - 26 0888-3270 2025/01/01 [Refereed][Not invited]
  • Heisei Yonezawa, Ansei Yonezawa, Itsuro Kajiwara
    Mechanical Systems and Signal Processing 224 (111961) 1 - 22 0888-3270 2025/01/01 [Refereed][Not invited]
     
    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.
  • Heisei Yonezawa, Ansei Yonezawa, Itsuro Kajiwara
    Mechanism and Machine Theory 203 (105825) 1 - 22 0094-114X 2024/11 [Refereed][Not invited]
  • Shuichi Yahagi, Itsuro Kajiwara
    IEEE Access 12 147882 - 147893 2024/10 [Refereed][Not invited]
  • Yoshifusa ITO, Masaki HIRATA, Heisei YONEZAWA, Shota SATO, Takashi HATANO, Chiaki NISHIDOME, Itsuro KAJIWARA
    Transactions of the JSME 1 - 20 2024/08 [Refereed][Not invited]
  • Ansei Yonezawa, Heisei Yonezawa, Shuichi Yahagi, Itsuro Kajiwara
    ISA Transactions 152 208 - 216 0019-0578 2024/07 [Refereed][Not invited]
  • 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 1464-4193 2024/04/01 [Refereed][Not invited]
     
    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.
  • Masaki Hirata, Heisei Yonezawa, Ansei Yonezawa, Itsuro Kajiwara
    International Journal of Control (First published online) 1 - 13 0020-7179 2024/04/01 [Refereed][Not invited]
  • Ansei Yonezawa, Heisei Yonezawa, Itsuro Kajiwara
    IEEE Transactions on Cybernetics 54 (9) 4903 - 4914 2168-2267 2024/03/28 [Refereed][Not invited]
  • Heisei Yonezawa, Ansei Yonezawa, Itsuro Kajiwara
    Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering (First published online) 1 - 14 0954-4070 2024/03/24 [Refereed][Not invited]
     
    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.
  • Toshiki Hiruta, Hiroki Ishihara, Naoki Hosoya, Shingo Maeda, Kentaro Takagi, Itsuro Kajiwara
    Smart Materials and Structures 0964-1726 2024/02/12 [Refereed][Not invited]
     
    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.
  • Shuichi Yahagi, Itsuro Kajiwara
    Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 1 - 13 0954-4070 2024/01/09 
    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.
  • Heisei Yonezawa, Ansei Yonezawa, Itsuro Kajiwara
    IEEE Access 12 11972 - 11986 2024/01 [Refereed][Not invited]
  • Heisei Yonezawa, Ansei Yonezawa, Itsuro Kajiwara
    ASME 2023 International Mechanical Engineering Congress and Exposition 6 (Paper No: IMECE2023-113274) 2023/10/29 [Refereed][Not invited]
     
    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.
  • Ansei Yonezawa, Heisei Yonezawa, Itsuro Kajiwara
    ASME 2023 International Mechanical Engineering Congress and Exposition 6 (Paper No: IMECE2023-112871) 2023/10/29 [Refereed][Not invited]
     
    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.
  • Shuichi Yahagi, Itsuro Kajiwara
    2023 23rd International Conference on Control, Automation and Systems (ICCAS) No. TuB2-2 2023/10/17 [Refereed][Not invited]
  • Ansei Yonezawa, Heisei Yonezawa, Itsuro Kajiwara
    Mechanical Systems and Signal Processing 200 (110526) 110526 - 110526 0888-3270 2023/10 [Refereed][Not invited]
  • Heisei Yonezawa, Ansei Yonezawa, Itsuro Kajiwara
    IEEE Access 11 93935 - 93947 2023/09 [Refereed][Not invited]
  • 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 0954-4070 2023/06/02 [Refereed][Not invited]
     
    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.
  • Shuichi Yahagi, Itsuro Kajiwara
    IEEE Access 1 - 12 2023/06 [Refereed][Not invited]
  • Qi Liu, Hong Lu, Heisei Yonezawa, Ansei Yonezawa, Itsuro Kajiwara, Ben Wang
    Mathematics 11 (10) 2259 - 2259 2023/05/11 [Refereed][Not invited]
     
    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.
  • Toshiki Hiruta, Kaishi Sasaki, Naoki Hosoya, Shingo Maeda, Kentaro Takagi, Itsuro Kajiwara
    Electroactive Polymer Actuators and Devices (EAPAD) XXV 12482 41 - 48 2023/04/28 [Refereed][Not invited]
  • Ansei Yonezawa, Heisei Yonezawa, Itsuro Kajiwara
    Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science (published online)  0954-4062 2022/12/21 [Refereed][Not invited]
     
    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.
  • Heisei Yonezawa, Ansei Yonezawa, Takashi Hatano, Shigeki Hiramatsu, Chiaki Nishidome, Itsuro Kajiwara
    2022 10th International Conference on Control, Mechatronics and Automation (ICCMA) 108 - 115 2022/11/09 [Refereed][Not invited]
  • Ansei Yonezawa, Heisei Yonezawa, Itsuro Kajiwara
    2022 10th International Conference on Control, Mechatronics and Automation (ICCMA) 88 - 93 2022/11/09 [Refereed][Not invited]
  • Tatsunari Sakai, Shuichi Yahagi, Itsuro Kajiwara
    IEEE Access 10 120475 - 120491 2022/11 [Refereed][Not invited]
  • Heisei Yonezawa, Ansei Yonezawa, Takashi Hatano, Shigeki Hiramatsu, Chiaki Nishidome, Itsuro Kajiwara
    Mechanism and Machine Theory 175 104957 - 104957 0094-114X 2022/09 [Refereed][Not invited]
  • Shuichi Yahagi, Itsuro Kajiwara
    IEEE Access 10 72773 - 72784 2022/07 [Refereed]
  • Shuichi Yahagi, Itsuro Kajiwara
    IEEE Control Systems Letters 1 - 6 2022/06 [Refereed][Not invited]
  • Ansei Yonezawa, Heisei Yonezawa, Itsuro Kajiwara
    Mechanical Systems and Signal Processing 170 108801 - 108801 0888-3270 2022/05 [Refereed][Not invited]
  • Yuto Sato, Heisei Yonezawa, Ansei Yonezawa, Itsuro Kajiwara
    Journal of Vibration Engineering & Technologies (published online) 1 - 14 2523-3920 2022/02/08 [Refereed][Not invited]
     
    Abstract Purpose 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. Methods and Results 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. Conclusions 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.
  • Ansei Yonezawa, Heisei Yonezawa, Itsuro Kajiwara
    Mechanical Systems and Signal Processing 165 (108313) 1 - 18 0888-3270 2022/02 [Refereed]
     
    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.
  • Naoki Hosoya, Tsubasa Katsumata, Itsuro Kajiwara, Takashi Onuma, Atsushi Kanda
    Optics and Lasers in Engineering 148 (106770) 1 - 10 0143-8166 2022/01 [Refereed]
  • Toshiki Hiruta, Kaishi Sasaki, Naoki Hosoya, Shingo Maeda, Itsuro Kajiwara
    Postharvest Biology and Technology 182 (111697) 1 - 8 0925-5214 2021/12 [Refereed]
  • 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) 2021/11 [Refereed][Not invited]
  • Ansei Yonezawa, Heisei Yonezawa, Itsuro Kajiwara
    Proceedings of International Mechanical Engineering Congress & Exposition (IMECE2021) 095440622211408 (Paper: 69100) (published online)  0954-4062 2021/11 [Refereed][Not invited]
     
    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 2021/10 [Refereed][Not invited]
  • Shuichi Yahagi, Itsuro Kajiwara
    Proceedings of the 21st International Conference on Control, Automation and Systems (TC3-2) 1424 - 1429 2093-7121 2021/10 [Refereed][Not invited]
     
    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.
  • Shuichi Yahagi, Itsuro Kajiwara
    Asian Journal of Control (published online) 1 - 16 1561-8625 2021/08/18 [Refereed]
  • Shuichi Yahagi, Itsuro Kajiwara
    Advances in Mechanical Engineering 13 (8) 1 - 12 1687-8140 2021/08 [Refereed]
     
    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.
  • Toshiki Hiruta, Naoki Hosoya, Shingo Maeda, Itsuro Kajiwara
    Sensors and Actuators A: Physical 330 (112830) 1 - 8 0924-4247 2021/05 [Refereed][Not invited]
  • Shuichi Yahagi, Itsuro Kajiwara
    Measurement and Control 54 (5-6) 1026 - 1042 0020-2940 2021/04/29 [Refereed][Not invited]
     
    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.
  • Nayuta Arai, Masafumi Miyake, Kengo Yamamoto, Itsuro Kajiwara, Naoki Hosoya
    Foods 10 (323) 1 - 16 2021/02/03 [Refereed]
     
    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.
  • Toshiki Hiruta, Naoki Hosoya, Shingo Maeda, Itsuro Kajiwara
    International Journal of Mechanical Sciences 191 (106049) 1 - 10 0020-7403 2021/02 [Refereed][Not invited]
  • Heisei Yonezawa, Itsuro Kajiwara, Chiaki Nishidome, Takashi Hatano, Masato Sakata, Shigeki Hiramatsu
    Journal of Automobile Engineering 235 (2-3) 773 - 783 0954-4070 2021/02 [Refereed]
     
    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.
  • H. Yonezawa, I. Kajiwara, C. Nishidome, T. Hatano, M. Sakata, S. Hiramatsu
    Vibration Engineering for a Sustainable Future 1 87 - 93 2021 [Refereed][Not invited]
  • Takanori Niikura, Naoki Hosoya, Shinji Hashimura, Itsuro Kajiwara, Francesco Giorgio-Serchi
    Vibration Engineering for a Sustainable Future 2 191 - 196 2021 [Refereed][Not invited]
  • Heisei Yonezawa, Itsuro Kajiwara, Shota Sato, Chiaki Nishidome, Takashi Hatano, Shigeki Hiramatsu
    IEEE Access 9 12002 - 12018 2021/01 [Refereed][Not invited]
  • Ansei Yonezawa, Itsuro Kajiwara, Heisei Yonezawa
    IEEE Access 9 4351 - 4363 2021/01 [Refereed][Not invited]
  • Naoki Hosoya, Takanori Niikura, Shinji Hashimura, Itsuro Kajiwara, Francesco Giorgio-Serchi
    Measurement: Journal of the International Measurement Confederation 162 (107914) 1 - 10 0263-2241 2020/10/01 [Refereed][Not invited]
     
    © 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.
  • Ansei Yonezawa, Itsuro Kajiwara, Heisei Yonezawa
    Journal of Vibration and Control 27 (11-12) 1324 - 1335 1077-5463 2020/07/02 [Refereed][Not invited]
     
    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 2020/04 [Refereed][Not invited]
  • 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 2020/01 [Refereed][Not invited]
  • 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 2019/09 [Refereed][Not invited]
  • 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  2019/08 [Refereed][Not invited]
  • 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 2019/08 [Refereed][Not invited]
  • 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 2019/07 [Refereed][Not invited]
  • 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.  2019/06 [Refereed][Not invited]
  • Yonezawa, H, Kajiwara, I, Nishidome, C, Hiramatsu, S, Sakata, M, Hatano, T
    Journal of Advanced Mechanical Design, Systems, and Manufacturing 13 (1) 18-00430  1881-3054 2019 [Refereed][Not invited]
     
    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 2018/12 [Refereed][Not invited]
  • 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  2018/12 [Refereed][Not invited]
  • Itsuro Kajiwara, Ryosuke Akita, Naoki Hosoya
    Mechanical Systems and Signal Processing 111 570 - 579 1096-1216 2018/10/01 [Refereed][Not invited]
     
    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 2018/08 [Refereed][Not invited]
  • Itsuro Kajiwara, Keiichiro Furuya, Shinichi Ishizuka
    Mechanical Systems and Signal Processing 107 396 - 408 1096-1216 2018/07/01 [Refereed][Not invited]
     
    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.
  • Hosoya Naoki, Yoshinaga Atsushi, Kanda Atsushi, Kajiwara Itsuro
    International journal of mechanical sciences Elsevier 140 (140) 486 - 492 0020-7403 2018/05 [Refereed][Not invited]
  • Sunao Tomita, Hayato Suzuki, Itsuro Kajiwara, Gen Nakamura, Yu Jiang, Mikio Suga, Takayuki Obata, Shigeru Tadano
    Journal of Visualization 21 (1) 133 - 145 1343-8875 2018/02/01 [Refereed][Not invited]
     
    © 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.].
  • Hosoya, N, Umino, R, Kanda, A, Kajiwara, I, Yoshinaga, A
    Journal of Vibration and Control 24 (24) 5842 - 5853 1077-5463 2018 [Refereed][Not invited]
     
    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 [Refereed][Not invited]
  • 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 2017/12 [Refereed][Not invited]
  • 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 2017/11 [Refereed][Not invited]
  • 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 2017/09 [Refereed][Not invited]
  • Naoki Hosoya, Michiru Mishima, Itsuro Kajiwara, Shingo Maeda
    POSTHARVEST BIOLOGY AND TECHNOLOGY 128 11 - 17 0925-5214 2017/06 [Refereed][Not invited]
     
    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.
  • Yuelin Zhang, Toshiki Hiruta, Itsuro Kajiwara, Naoki Hosoya
    JOURNAL OF VIBRATION AND CONTROL 23 (10) 1681 - 1692 1077-5463 2017/06 [Refereed][Not invited]
     
    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.
  • Shinichi Ishizuka, Itsuro Kajiwara, Junichi Sato, Yoshifumi Hanamura, Satoshi Hanawa
    TRANSACTIONS OF THE INSTITUTE OF MEASUREMENT AND CONTROL 39 (1) 114 - 128 0142-3312 2017/01 [Refereed][Not invited]
     
    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.
  • S. Ishizuka, I. Kajiwara, J. Sato, Y. Hanamura
    Journal of Physics: Conference Series 744 (1) 1742-6596 2016/10/03 [Refereed][Not invited]
     
    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.
  • Naoki Hosoya, Itsuro Kajiwara, Koh Umenai
    JOURNAL OF VIBRATION AND CONTROL 22 (17) 3649 - 3658 1077-5463 2016/10 [Refereed][Not invited]
     
    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.
  • N. Hosoya, M. Nagata, I. Kajiwara, R. Umino
    EXPERIMENTAL MECHANICS 56 (7) 1305 - 1311 0014-4851 2016/09 [Refereed][Not invited]
     
    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.
  • N. Hosoya, R. Umino, I. Kajiwara, S. Maeda, T. Onuma, A. Mihara
    EXPERIMENTAL MECHANICS 56 (2) 339 - 343 0014-4851 2016/02 [Refereed][Not invited]
     
    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.
  • Honda, S, Narita, Y, Kajiwara, I
    Mechanical Engineering Journal 一般社団法人 日本機械学会 3 (1) 14-00561 - 00561-14-00561 2187-9745 2016 [Refereed][Not invited]
     
    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.
  • 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 2016 [Refereed][Not invited]
     
    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.
  • Shinichi Ishizuka, Itsuro Kajiwara, Junichi Sato, Yoshifumi Hanamura
    2015 3RD INTERNATIONAL CONFERENCE ON CONTROL, MECHATRONICS AND AUTOMATION (ICCMA 2015) 42 2261-236X 2016 [Refereed][Not invited]
     
    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 2015/11 [Refereed][Not invited]
  • 神田淳, 細矢直基, 梶原逸朗
    可視化情報学会誌 35 (Suppl.2) 45‐46  0916-4731 2015/09/15 [Not refereed][Not invited]
  • 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 2015/09 [Refereed][Not invited]
  • 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 2015/05 [Refereed][Not invited]
  • 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 2015/05 [Refereed][Not invited]
  • SUZUKI Hayato, TADANO Shigeru, GOTO Mototeru, YAMADA Satoshi, FUJISAKI Kazuhiro, KAJIWARA Itsuro, SUGA Mikio, NAKAMURA Gen
    Mechanical Engineering Journal 一般社団法人 日本機械学会 2 (3) 14 - 00417-14-00417 2187-9745 2015 [Refereed][Not invited]
     
    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.
  • Keiichiro Furuya, Shinichi Ishizuka, Itsuro Kajiwara
    JOURNAL OF ADVANCED MECHANICAL DESIGN SYSTEMS AND MANUFACTURING 9 (2) No.15-00061  1881-3054 2015 [Refereed][Not invited]
     
    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.
  • Shinichi Ishizuka, Itsuro Kajiwara
    JOURNAL OF ADVANCED MECHANICAL DESIGN SYSTEMS AND MANUFACTURING 9 (2) No.14-00390  1881-3054 2015 [Refereed][Not invited]
     
    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.
  • Naoki Hosoya, Itsuro Kajiwara, Tatsuo Inoue, Koh Umenai
    JOURNAL OF SOUND AND VIBRATION 333 (18) 4254 - 4264 0022-460X 2014/09 [Refereed][Not invited]
     
    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.
  • Umenai K, Hosoya N, Kajiwara I
    Proceedings of 12th International Conference on Motion and Vibration Control 2A32 2014/08 [Refereed][Not invited]
  • Furuya K, Ishizuka S, Kajiwara I, Zhang Y
    Proceedings of 12th International Conference on Motion and Vibration Control 3B23 2014/08 [Refereed][Not invited]
  • Ishizuka S, Kajiwara, I.
    Proceedings of 12th International Conference on Motion and Vibration Control 2A14 2014/08 [Refereed][Not invited]
  • Youfeng Yue, Takayuki Kurokawa, Md Anamul Haque, Tasuku Nakajima, Takayuki Nonoyama, Xufeng Li, Itsuro Kajiwara, Jian Ping Gong
    NATURE COMMUNICATIONS 5 (4659) 2041-1723 2014/08 [Refereed][Not invited]
     
    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.
  • Feblil Huda, Itsuro Kajiwara, Naoki Hosoya
    JOURNAL OF SOUND AND VIBRATION 333 (16) 3609 - 3624 0022-460X 2014/08 [Refereed][Not invited]
     
    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.
  • S. Tomita, H. Suzuki, I. Kajiwara, S. Tadano, G. Nakamura, Y. Jiang
    IFMBE Proceedings 43 (43) 168 - 171 1680-0737 2014 [Refereed][Not invited]
     
    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.
  • Hayato Suzuki, Mikio Suga, Kazuhiro Fujisaki, Itsuro Kajiwara, Gen Nakamura, Kogo Yoshikawa, Shigeru Tadano
    IFMBE Proceedings 43 156 - 159 1680-0737 2014 [Refereed][Not invited]
     
    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.
  • Hayato Suzuki, Mikio Suga, Kazuhiro Fujisaki, Itsuro Kajiwara, Gen Nakamura, Kogo Yoshikawa, Shigeru Tadano
    IFMBE Proceedings 43 156 - 159 1680-0737 2014 [Refereed][Not invited]
     
    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.
  • Feblil Huda, Itsuro Kajiwara, Naoki Hosoya
    HEALTH MONITORING OF STRUCTURAL AND BIOLOGICAL SYSTEMS 2014 9064 0277-786X 2014 [Refereed][Not invited]
     
    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.
  • Shota Yabui, Itsuro Kajiwara, Ryohei Okita
    JOURNAL OF ADVANCED MECHANICAL DESIGN SYSTEMS AND MANUFACTURING 8 (1) 1 - 12 1881-3054 2014 [Refereed][Not invited]
     
    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.
  • S. Tomita, H. Suzuki, I. Kajiwara, S. Tadano, G. Nakamura, Y. Jiang
    IFMBE Proceedings 43 168 - 171 1680-0737 2014 [Refereed][Not invited]
     
    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.
  • 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 2014 [Refereed][Not invited]
     
    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.
  • Shota Yabui, Itsuro Kajiwara
    2014 IEEE 13TH INTERNATIONAL WORKSHOP ON ADVANCED MOTION CONTROL (AMC) 598 - 603 1943-6572 2014 [Refereed][Not invited]
     
    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.
  • Shota Yabui, Atushi Okuyama, Takenori Atsumi, Itsuro Kajiwara
    JOURNAL OF ADVANCED MECHANICAL DESIGN SYSTEMS AND MANUFACTURING 8 (3) 1 - 14 1881-3054 2014 [Refereed][Not invited]
     
    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.
  • Feblil Huda, Itsuro Kajiwara, Naoki Hosoya, Shozo Kawamura
    MECHANICAL SYSTEMS AND SIGNAL PROCESSING 40 (2) 589 - 604 0888-3270 2013/11 [Refereed][Not invited]
     
    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.
  • Naoki Hosoya, Masaki Nagata, Itsuro Kajiwara
    Journal of Sound and Vibration 332 (19) 4572 - 4583 0022-460X 2013/09/16 [Refereed][Not invited]
     
    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 2013/09 [Refereed][Not invited]
  • 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 2013/07 [Refereed][Not invited]
  • 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  2013/06 [Refereed][Not invited]
  • Itsuro Kajiwara, Naoki Hosoya
    ASME 2013 Dynamic Systems and Control Conference, DSCC 2013 3 2013 [Refereed][Not invited]
     
    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.
  • Shota Yabui, Itsuro Kajiwara, Shigeo Nakamura, Takenori Atsumi
    Journal of Advanced Mechanical Design, Systems and Manufacturing 7 (6) 903 - 918 1881-3054 2013 [Refereed][Not invited]
     
    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.
  • Feblil Huda, Itsuro Kajiwara, Naoki Hosoya, Shozo Kawamura
    HEALTH MONITORING OF STRUCTURAL AND BIOLOGICAL SYSTEMS 2013 8695 0277-786X 2013 [Refereed][Not invited]
     
    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.
  • Shota Yabui, Itsuro Kajiwara, Ryohei Okita
    PROCEEDINGS OF THE ASME 2013 DYNAMIC SYSTEMS AND CONTROL CONFERENCE (DSCC2013), VOL. 1 4014 2013 [Refereed][Not invited]
     
    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 2012/05 [Refereed][Not invited]
  • Naoki Hosoya, Itsuro Kajiwara, Takahiko Hosokawa
    JOURNAL OF SOUND AND VIBRATION 331 (6) 1355 - 1365 0022-460X 2012/03 [Refereed][Not invited]
     
    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.
  • 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 0387-5024 2012 [Refereed][Not invited]
     
    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.
  • 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 [Refereed][Not invited]
     
    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.
  • 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 0387-5024 2012 [Refereed][Not invited]
     
    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.
  • 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 [Refereed][Not invited]
     
    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.
  • TADANO Shigeru, FUJISAKI Kazuhiro, SUZUKI Hayato, TAKAO Seishin, SUGA Mikio, KAJIWARA Itsuro, YAMAMOTO Toru, JIANG Yu, NAKAMURA Gen
    Journal of Biomechanical Science and Engineering 一般社団法人 日本機械学会 7 (4) 463 - 474 1880-9863 2012 [Refereed][Not invited]
     
    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.
  • 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 0387-5024 2012 [Refereed][Not invited]
     
    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.
  • 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 0387-5024 2012 [Refereed][Not invited]
     
    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.
  • 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 2012 [Refereed][Not invited]
     
    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.
  • Kajiwara, I., Miyamoto, D, Hosoya, N, Nishidome, C
    Journal of System Design and Dynamics The Japan Society of Mechanical Engineers 5 (8) 1559 - 1571 1881-3046 2011/12 [Refereed][Not invited]
     
    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.
  • Itsuro Kajiwara, Naoki Hosoya
    JOURNAL OF SOUND AND VIBRATION 330 (21) 5045 - 5057 0022-460X 2011/10 [Refereed][Not invited]
     
    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.
  • Shinya Honda, Itsuro Kajiwara, Yoshihiro Narita
    JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES 22 (13) 1419 - 1430 1045-389X 2011/09 [Refereed][Not invited]
     
    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.
  • Honda S, Kosaka K, Narita Y, Kajiwara I
    Proceedings of ICCM International Conferences on Composite Materials IF0541 2011/08 [Refereed][Not invited]
  • Shinya Honda, Yoshihiro Narita, Itsuro Kajiwara, Satoshi Nakamura
    DYNAMICS FOR SUSTAINABLE ENGINEERING, 2011, VOL 3 1462 - 1470 2011 [Refereed][Not invited]
     
    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.
  • Kajiwara, I, Harada, H
    Journal of System Design and Dynamics The Japan Society of Mechanical Engineers 5 (6) 1202 - 1213 1881-3046 2011 [Refereed][Not invited]
     
    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.
  • Hosoya N, Kajiwara, I., Hosokawa T
    Transactions of the Japan Society of Mechanical Engineers Series C The Japan Society of Mechanical Engineers 77 (773) 102 - 113 0387-5024 2011 [Refereed][Not invited]
     
    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.
  • Kajiwara I, Obara K
    Transactions of the Japan Society of Mechanical Engineers Series C The Japan Society of Mechanical Engineers 77 (779) 2662 - 2672 0387-5024 2011 [Refereed][Not invited]
     
    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.
  • 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 0387-5024 2011 [Refereed][Not invited]
     
    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.
  • Nakamura S, Kajiwara I, Arisaka T
    Transactions of the Japan Society of Mechanical Engineers Series C The Japan Society of Mechanical Engineers 77 (775) 847 - 857 0387-5024 2011 [Refereed][Not invited]
     
    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.
  • 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 0387-5024 2011 [Refereed][Not invited]
     
    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.
  • I. Kajiwara, D. Miyamoto, N. Hosoya, C. Nishidome
    HEALTH MONITORING OF STRUCTURAL AND BIOLOGICAL SYSTEMS 2011 7984 0277-786X 2011 [Refereed][Not invited]
     
    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.
  • Miyamoto D, Kajiwara I, Hosoya N, Nishidome C
    Transactions of the Japan Society of Mechanical Engineers Series C 77 (777) 1760 - 1771 2011 [Refereed][Not invited]
  • 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 0387-5024 2010 [Refereed][Not invited]
     
    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.
  • Kenya Obara, Itsuro Kajiwara
    PROCEEDINGS OF THE ASME CONFERENCE ON SMART MATERIALS, ADAPTIVE STRUCTURES AND INTELLIGENT SYSTEMS, 2010, VOL 2 3617 559 - 564 2153-2001 2010 [Refereed][Not invited]
     
    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.
  • Kajiwara I, Nakano K, Harada H
    Journal of System Design and Dynamics The Japan Society of Mechanical Engineers 4 (6) 941 - 952 1881-3046 2010 [Refereed][Not invited]
     
    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.
  • 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 2153-2001 2010 [Refereed][Not invited]
     
    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.
  • N. Hosoya, I. Kajiwara, T. Hosokawa
    PROCEEDINGS OF ISMA2010 - INTERNATIONAL CONFERENCE ON NOISE AND VIBRATION ENGINEERING INCLUDING USD2010 1747 - 1757 2010 [Refereed][Not invited]
     
    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 2009/11 [Refereed][Not invited]
  • 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 0387-5024 2009 [Refereed][Not invited]
     
    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.
  • 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 0387-5024 2009 [Refereed][Not invited]
     
    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.
  • Itsuro Kajiwara, Toshio Uchiyama, Toshihiro Airisaka
    MOTION AND VIBRATION CONTROL 165 - + 2009 [Refereed][Not invited]
     
    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.
  • Kajiwara, I., Takahashi, M, Arisaka, T
    Journal of System Design and Dynamics The Japan Society of Mechanical Engineers 3 (6) 906 - 917 1881-3046 2009 [Refereed][Not invited]
     
    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.
  • ITSURO KAJIWARA, RYO TSUCHIYA
    Journal of System Design and Dynamics The Japan Society of Mechanical Engineers 2 (1) 413 - 424 1881-3046 2008 [Not refereed][Not invited]
     
    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.
  • Kajiwara I, Tsuchiya R, Ishizuka S
    Proceedings of 19th International Conference on Adaptive Structures and Technologies 2008, ICAST 2008 718 - 729 2008 [Refereed][Not invited]
  • Kimiaki Ono, Itsuro Kajiwara
    INTERNATIONAL JOURNAL OF VEHICLE DESIGN 43 (1-4) 184 - 199 0143-3369 2007 [Refereed][Not invited]
     
    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.
  • Hiroyuki Sato, Chiaki Nishidome, Itsuro Kajiwara, A. Koichi Hayashi
    INTERNATIONAL JOURNAL OF VEHICLE DESIGN 43 (1-4) 322 - 340 0143-3369 2007 [Refereed][Not invited]
     
    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.
  • Kajiwara, I., Kato H, Kondo M, Sato Y
    Transactions of the Japan Society of Mechanical Engineers Series C 一般社団法人日本機械学会 73 (732) 2246 - 2254 0387-5024 2007 [Refereed][Not invited]
     
    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.
  • 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 0143-3369 2007 [Refereed][Not invited]
     
    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.
  • Kajiwara I, Tsuchiya R
    Proceedings of the World Forum on Smart Materials and Smart Structures Technology 453 2007 [Refereed][Not invited]
  • Itsuro Kajiwara, Kentaro Hoshino, Shinji Hara, Daisuke Shiokata, Takashi Yabe
    Transactions of the Japan Society for Aeronautical and Space Sciences 49 (164) 71 - 76 0549-3811 2006 [Not refereed][Not invited]
     
    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.
  • Tetsuya Okita, Kentaro Hoshino, Itsuro Kajiwara
    BEAMED ENERGY PROPULSION 830 553 - + 0094-243X 2006 [Refereed][Not invited]
     
    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.
  • Ono K, Kajiwara I
    Proceedings of 11th AIAA/ISSMO Multidisciplinary Analysis and Optimization Conference AIAA-2006-7046 2006 [Refereed][Not invited]
  • Tsuchiya R, Kajiwara, I.
    Transactions of the Japan Society of Mechanical Engineers Series C 72 (713) 53 - 60 2006 [Refereed][Not invited]
  • F Ohashi, Kajiwara, I., M Iwadare, T Arisaka
    MICROSYSTEM TECHNOLOGIES-MICRO-AND NANOSYSTEMS-INFORMATION STORAGE AND PROCESSING SYSTEMS 11 (8-10) 711 - 717 0946-7076 2005/08 [Not refereed][Not invited]
     
    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 [Refereed][Not invited]
  • 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 [Refereed][Not invited]
  • 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 2005 [Refereed][Not invited]
     
    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.
  • H Ishikawa, Kajiwara, I, K Hoshino, T Yabe, S Uchida, Y Shimane
    BEAMED ENERGY PROPULSION 702 342 - 353 0094-243X 2004 [Refereed][Not invited]
     
    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 [Refereed][Not invited]
  • 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 [Refereed][Not invited]
  • 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 [Refereed][Not invited]
  • Itsuro Kajiwara, Kentaro Hoshino, Hiroyasu Ishikawa, Yoshichika Shimane, Takashi Yabe, Shigeaki Uchida
    Theoretical and Applied Mechanics Japan 53 115 - 124 1349-4244 2004 [Refereed][Not invited]
     
    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.
  • Hoshino K, Kajiwara, I., Hara S, Ishikawa H, Shiokata D
    Proceedings of the IEEE International Conference on Control Applications 1 1 - 6 2004 [Refereed][Not invited]
  • Iwadare M, Kajiwara I, Tsuchiya R, Horie M
    Proceedings of the IEEE International Conference on Control Applications 2 1717 - 1722 2004 [Refereed][Not invited]
  • 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 0947-8396 2003/07 [Refereed][Not invited]
     
    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.
  • C Nishidome, Kajiwara, I
    JSME INTERNATIONAL JOURNAL SERIES C-MECHANICAL SYSTEMS MACHINE ELEMENTS AND MANUFACTURING 46 (2) 565 - 571 1344-7653 2003/06 [Refereed][Not invited]
     
    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.
  • Kajiwara, I, H Ishikawa, S Furuya, T Yabe, C Nishidome
    BEAMED ENERGY PROPULSION 664 545 - 556 0094-243X 2003 [Refereed][Not invited]
     
    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 [Refereed][Not invited]
  • 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 [Refereed][Not invited]
  • Kajiwara I, Uehara M
    Transactions of the Japan Society of Mechanical Engineers Series C 一般社団法人日本機械学会 69 (684) 2093 - 2100 0387-5024 2003 [Refereed][Not invited]
     
    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.
  • Nishidome C, Kajiwara, I., Nagamatsu A
    Transactions of the Japan Society of Mechanical Engineers Series C 社団法人日本機械学会 69 (677) 10 - 17 0387-5024 2003 [Refereed][Not invited]
     
    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.
  • 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 0003-6951 2002/06 [Refereed][Not invited]
     
    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 [Refereed][Not invited]
  • 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 [Refereed][Not invited]
  • C Nishidome, Kajiwara, I
    SICE 2002: PROCEEDINGS OF THE 41ST SICE ANNUAL CONFERENCE, VOLS 1-5 1129 - 1134 2002 [Refereed][Not invited]
     
    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.
  • F Ohashi, Kajiwara, I., T Omori, T Arisaka
    SICE 2002: PROCEEDINGS OF THE 41ST SICE ANNUAL CONFERENCE, VOLS 1-5 1117 - 1122 2002 [Refereed][Not invited]
     
    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.
  • H Ishikawa, Kajiwara, I, T Yabe
    SICE 2002: PROCEEDINGS OF THE 41ST SICE ANNUAL CONFERENCE, VOLS 1-5 599 - 604 2002 [Refereed][Not invited]
     
    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.
  • 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 0387-5024 2002 [Refereed][Not invited]
     
    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.
  • 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 0277-786X 2002 [Refereed][Not invited]
     
    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 [Not refereed][Not invited]
  • 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 0387-5024 2001 [Not refereed][Not invited]
     
    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.
  • Kajiwara, I., Yambe, K, Nishidome, C
    Proceedings of the ASME Design Engineering Technical Conference VIB-21326 2001 [Refereed][Not invited]
     
    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.
  • Kajiwara I, Uehara M
    Proceedings of 19th AIAA Applied Aerodynamics Conference 2001-1555 2001 [Refereed][Not invited]
  • Kajiwara, I, RT Haftka
    JSME INTERNATIONAL JOURNAL SERIES C-MECHANICAL SYSTEMS MACHINE ELEMENTS AND MANUFACTURING 43 (3) 684 - 690 1340-8062 2000/09 [Refereed][Not invited]
     
    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 [Refereed][Not invited]
  • Itsuro Kajiwara, Raphael T. Haftka
    JSME International Journal, Series C: Mechanical Systems, Machine Elements and Manufacturing 43 (3) 684 - 690 1344-7653 2000 [Refereed][Not invited]
     
    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.
  • Y Kawabe, S Yoshida, S Saegusa, Kajiwara, I, A Nagamatsu
    JOURNAL OF MECHANICAL DESIGN 121 (2) 188 - 194 1050-0472 1999/06 [Refereed][Not invited]
     
    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.
  • Hiroshi Shimojima, Yoshihiro Matsunaga, Sekiya Koike, Itsuro Kajiwara
    Transactions of the Japan Society of Mechanical Engineers Series C 一般社団法人日本機械学会 65 (633) 1849 - 1856 0387-5024 1999/01 [Refereed][Not invited]
     
    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.
  • Kajiwara I, Nagamatsu A
    Proceedings of the IEEE International Conference on Systems, Man and Cybernetics 3 152 - 157 1999 [Refereed][Not invited]
  • Kajiwara Itsuro, Nagamatsu Akio
    Proceedings of IEEE Conference on Control Applications 86 - 91 1999 [Refereed][Not invited]
  • 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 [Refereed][Not invited]
  • ZY Guo, Kajiwara, I, A Nagamatsu
    JSME INTERNATIONAL JOURNAL SERIES C-MECHANICAL SYSTEMS MACHINE ELEMENTS AND MANUFACTURING 41 (2) 171 - 177 1340-8062 1998/06 [Refereed][Not invited]
     
    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 [Refereed][Not invited]
  • Itsuro Kajiwara, Masanao Fukuda, Hiroshi Shimojima
    Transactions of the Japan Society of Mechanical Engineers Series C 一般社団法人日本機械学会 64 (621) 1668 - 1675 0387-5024 1998/01 [Refereed][Not invited]
     
    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.
  • Itsuro Kajiwara, Katsuhiro Yambe, Hiroshi Shimojima
    Transactions of the Japan Society of Mechanical Engineers Series C 一般社団法人日本機械学会 64 (626) 3839 - 3846 0387-5024 1998/01 [Refereed][Not invited]
     
    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.
  • Kajiwara Itsuro, Nagamatsu Akio
    Proceedings of the International Conference on Inverse Problems in Engineering 253 - 260 1998 [Refereed][Not invited]
  • Kajiwara, I., ZY Guo, A Nagamatsu
    JSME INTERNATIONAL JOURNAL SERIES C-MECHANICAL SYSTEMS MACHINE ELEMENTS AND MANUFACTURING 40 (2) 197 - 202 1340-8062 1997/06 [Refereed][Not invited]
     
    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.
  • Kajiwara, I, ZY Guo, A Nagamatsu
    JSME INTERNATIONAL JOURNAL SERIES C-MECHANICAL SYSTEMS MACHINE ELEMENTS AND MANUFACTURING 40 (2) 197 - 202 1340-8062 1997/06 [Refereed][Not invited]
     
    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 [Refereed][Not invited]
  • Zhongyang Guo, Itsuro Kajiwara, Akio Nagamatsu, Tsutomu Sonehara
    SAE Technical Papers P-309 (2) 631 - 637 1997 [Refereed][Not invited]
     
    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.
  • 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 0191-2216 1997 [Refereed][Not invited]
     
    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.
  • 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 [Refereed][Not invited]
  • Kajiwara Itsuro, Takahashi Naoki, Nagamatsu Akio
    Transactions of the Japan Society of Mechanical Engineers Series C 一般社団法人日本機械学会 62 (599) 2556 - 2562 0387-5024 1996/07 [Refereed][Not invited]
     
    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 [Refereed][Not invited]
  • Sonehara, T, Kawai, K, Kubo, Y, Kajiwara, I., Nagamatsu, A.
    Journal of JSAE 自動車技術会 27 (4) 83 - 87 0287-8321 1996 [Refereed][Not invited]
  • 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 [Not refereed][Not invited]
  • I. Kajiwara, A. Nagamatsu, K. Seki, Y. Kotani
    37th AIAA/ASME/ASCE/AHS/ASC Structure, Structural Dynamics and Materials Conference CP962 1005 - 1015 1996 [Refereed][Not invited]
     
    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.
  • Kajiwara Itsuro, Sasaki Yasutaka, Nagamatsu Akio
    Transactions of the Japan Society of Mechanical Engineers Series C 62 (597) 1731 - 1738 1996 [Refereed][Not invited]
  • Tsujioka, K, Kajiwara, I, Nagamatsu, A
    AIAA Journal 34 (1) 159 - 165 0001-1452 1996 [Not refereed][Not invited]
     
    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.
  • Kazuaki Tsujioka, Itsuro Kajiwara, Akio Nagamatsu
    Transaction of the Japan Society of Mechanical Engineers 61 (583) 967 - 974 0387-5024 1995 [Refereed][Not invited]
  • Kazuaki Tsujioka, Itsuro Kajiwara, Akio Nagamatsu
    Transactions of the Japan Society of Mechanical Engineers 61 (587) 2704 - 2711 0387-5024 1995/01 [Refereed][Not invited]
     
    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.
  • Itsuro Kajiwara, Yoshiko Kawabe, Shinobu Yoshida, Shozo Saegusa, Akio Nagamatsu
    Transactions of the Japan Society of Mechanical Engineers Series C 一般社団法人日本機械学会 61 (587) 2662 - 2667 0387-5024 1995/01 [Refereed][Not invited]
     
    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.
  • Kajiwara I, Nagamatsu A, Kawabe Y, Yoshida S, Saegusa S
    Proceedings of ASME PVP Conference 305 279 - 283 1995 [Refereed][Not invited]
  • Tsujioka Kazuaki, Kajiwara Itsuro, Nagamatsu Akio
    Proceedings of ASME Pressure Vessels and Piping Division (Publication) PVP 305 297 - 303 1995 [Refereed][Not invited]
  • Kajiwara I, Tsujioka K, Nagamatsu A
    Proceedings of 1995 ASME Design Engineering Division (Publication) DE 84 (3 Pt C) 487 - 494 1995 [Refereed][Not invited]
  • Tsujioka K, Kajiwara, I., Nagamatsu A
    Proceedings of AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference 5 2983 - 2991 1995 [Refereed][Not invited]
  • Itsuro Kajiwara, Akio Nagamatsu
    Transactions of the Japan Society of Mechanical Engineers Series C 一般社団法人日本機械学会 60 (570) 368 - 373 0387-5024 1994/01 [Not refereed][Not invited]
  • I. Kajiwara, K. Tsujioka, A. Nagamatsu
    AIAA Journal 32 (4) 866 - 873 0001-1452 1994 [Refereed][Not invited]
     
    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.
  • KAJIWARA, I, A NAGAMATSU
    PROCEEDINGS OF THE 12TH INTERNATIONAL MODAL ANALYSIS CONFERENCE, VOLS 1 AND 2 2251 591 - 597 1994 [Refereed][Not invited]
  • KAJIWARA, I, A NAGAMATSU
    JOURNAL OF VIBRATION AND ACOUSTICS-TRANSACTIONS OF THE ASME 115 (4) 377 - 383 1048-9002 1993/10 [Refereed][Not invited]
     
    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 [Refereed][Not invited]
  • 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 [Refereed][Not invited]
  • Kajiwara, I., Tsujioka K, Nagamatsu A
    Proceedings of AIAA/ASME Structures, Structural Dynamics and Materials Conference (pt 3) 1409 - 1417 1993 [Refereed][Not invited]
  • Tsujioka, K., Kajiwara, I., Nagamatsu, A.
    Transaction of the Japan Society of Mechanical Engineers 59 (563) 2124 - 2131 1993 [Not refereed][Not invited]
  • Itsuro Kajiwara, Akio Nagamatsu
    Finite Elements in Analysis and Design 14 (2-3) 187 - 195 0168-874X 1993 [Refereed][Not invited]
     
    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.
  • Itsuro Kajiwara, Akio Nagamatsu
    Finite Elements in Analysis and Design 14 (2-3) 101 - 110 0168-874X 1993 [Refereed][Not invited]
     
    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.
  • KAJIWARA, I, A NAGAMATSU
    PROCEEDINGS OF THE 11TH INTERNATIONAL MODAL ANALYSIS CONFERENCE, VOLS 1 AND 2 1923 (pt 2) 883 - 889 1993 [Refereed][Not invited]
  • 梶原逸朗, 長松昭男, 稲垣亨
    Transactions of the Society of Instrument and Control Engineers The Society of Instrument and Control Engineers 28 (3) 383 - 391 0453-4654 1992 [Refereed][Not invited]
     
    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 [Refereed][Not invited]
  • 梶原逸朗, 稲垣亨, 長松昭男
    Transactions of the Japan Society of Mechanical Engineers 一般社団法人日本機械学会 58 (555) 3238 - 3245 0387-5024 1992 [Refereed][Not invited]
     
    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.
  • Itsuro Kajiwara, Tohru Inagaki, Akio Nagamatsu
    Transactions of the Japan Society of Mechanical Engineers Series C 一般社団法人日本機械学会 58 (552) 2365 - 2372 0387-5024 1992/01 [Refereed][Not invited]
     
    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.
  • Itsuro Kajiwara, Akio Nagamatsu, Masaaki Okuma, Toru Inagaki
    Transactions of the Japan Society of Mechanical Engineers Series C 58 (549) 1385 - 1391 0387-5024 1992/01 [Refereed][Not invited]
     
    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.
  • Kajiwara, I., Nagamatsu A
    Proceedings of the 1991 Asia-Pacific Vibration Conference 2 61 - 66 1991 [Refereed][Not invited]
  • Kajiwara I, Nagamatsu A
    Proceedings of American Society of Mechanical Engineers, Design Engineering Division 38 179 - 184 1991 [Refereed][Not invited]
  • 梶原逸朗, 長松昭男
    Transactions of The Society of Instrument and Control Engineers 26 (10) 1140 - 1147 1990 [Refereed][Not invited]
  • Shigeo Yamashita, Itsuro Kajiwara, Kazuto Seto
    Transactions of the Japan Society of Mechanical Engineers Series C 一般社団法人日本機械学会 56 (528) 2107 - 2114 0387-5024 1990/01 [Refereed][Not invited]
     
    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.
  • Itsuro Kajiwara, Akio Nagamatsu
    Transactions of the Japan Society of Mechanical Engineers Series C 一般社団法人日本機械学会 56 (522) 391 - 397 0387-5024 1990/01 [Refereed][Not invited]
     
    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.
  • Itsuro Kajiwara, Kazuto Seto, Akio Nagamatsu, Hiroaki Morifuji, Nobuyuki Nakae
    Transactions of the Japan Society of Mechanical Engineers Series C 一般社団法人日本機械学会 55 (516) 2045 - 2052 0387-5024 1989/01 [Refereed][Not invited]
     
    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.
  • Kazuto Seto, Itsuro Kajiwara, Akio Nagamatsu, Hiroaki Morifuji
    Transactions of the Japan Society of Mechanical Engineers Series C 一般社団法人日本機械学会 55 (516) 2029 - 2036 0387-5024 1989/01 [Refereed][Not invited]
     
    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.
  • Itsuro Kajiwara, Kazuto Seto, Akio Nagamatsu
    Transactions of the Japan Society of Mechanical Engineers Series C 一般社団法人日本機械学会 55 (516) 2037 - 2044 0387-5024 1989/01 [Refereed][Not invited]
     
    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.
  • Kajiwara I, Agamatsu A, Seto K
    Proceedings of ASME PVP Conference 179 161 - 167 1989 [Refereed][Not invited]
  • Itsuro Kajiwara, Masaaki Ookuma, Akio Nagamatsu, Kazuto Seto
    Transactions of the Japan Society of Mechanical Engineers Series C 一般社団法人日本機械学会 54 (505) 2084 - 2091 0387-5024 1988/01 [Refereed][Not invited]
     
    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.

MISC

  • 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  2017/07/31  [Not refereed][Not invited]
  • 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  2016/09/30  [Not refereed][Not invited]
  • 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  2015/06/30  [Not refereed][Not invited]
  • 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  2013/06/28  [Not refereed][Not invited]
  • 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  [Not refereed][Not invited]
  • 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  [Not refereed][Not invited]
  • 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  2011/12/01  [Not refereed][Not invited]
  • 梶原 逸朗  日本機械学會誌  111-  (1077)  686  -687  2008/08/05
  • 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  [Not refereed][Not invited]
  • 梶原逸朗  機械の研究  58-  (9)  937  -944  2006  [Not refereed][Not invited]
  • 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  [Not refereed][Not invited]
  • 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  [Not refereed][Not invited]
  • 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  [Not refereed][Not invited]
  • 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  [Not refereed][Not invited]
  • 梶原逸朗  機械の研究  53-  (12)  1223  -1230  2001  [Not refereed][Not invited]
  • 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  [Not refereed][Not invited]
  • 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  [Not refereed][Not invited]
  • 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  [Not refereed][Not invited]
  • 梶原逸朗  システム／制御／情報  44-  (11)  623  -631  2000  [Not refereed][Not invited]
  • 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  [Not refereed][Not invited]
  • 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  [Not refereed][Not invited]

Books etc

  • 機械工学のための力学
    梶原 逸朗 (Contributor)
    丸善出版 2014
  • シミュレーション辞典
    梶原 逸朗 (Contributor)
    日本シミュレーション学会 2012
  • 制振工学ハンドブック
    梶原 逸朗 (Contributor)
    コロナ社 2008
  • 機械工学のための数学I －基礎数学－
    梶原 逸朗 (Contributor)
    朝倉書店 2007
  • 機械工学のための数学Ⅰ
    梶原 逸朗 (Contributor)
    朝倉書店 2007
  • 構造工学ハンドブック
    梶原 逸朗 (Contributor)
    丸善 2004
  • 最適設計ハンドブック
    梶原 逸朗 (Contributor)
    朝倉書店 2003
  • モード解析ハンドブック
    梶原 逸朗 (Contributor)
    コロナ社 1999
  • 音・振動のモード解析と制御
    梶原 逸朗 (Contributor)
    日本音響学会編、音響テクノロジーシリーズ,コロナ社 1996

Presentations

  • 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  [Not invited]
    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  2023/10
  • 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  [Not invited]
    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  2023/09
  • 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  [Not invited]
    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  2023/08
  • 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  [Not invited]
    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  2023/08
  • レーザー加振技術を用いた骨の弾性率推定  [Not invited]
    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  2022/12
  • 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  [Not invited]
    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  2022/12
  • 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  [Not invited]
    磯貝航, 梶原逸朗, 前田真吾, 細矢直基
    Dynamics and Design Conference 2022  2022/09
  • 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  [Not invited]
    坂井達成, 矢作修一, 梶原逸朗
    Dynamics and Design Conference 2022  2022/09
  • 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  [Not invited]
    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  2022/09
  • 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  [Not invited]
    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  2022/09
  • 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  [Not invited]
    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)  2021/12
  • 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  [Not invited]
    古怒田真悟, 荒井那由他, 梶原逸朗, 細矢直基
    Dynamics and Design Conference 2021  2021/09
  • 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  [Not invited]
    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  2021/09
  • 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）  [Not invited]
    若田祥, 前川知輝, 梶原逸朗, Ambroziński Łukasz, Pieczonka Łukasz, 細矢直基
    Dynamics and Design Conference 2021  2021/09
  • 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  [Not invited]
    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  2020/11
  • 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  [Not invited]
    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  2020/11
  • 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  [Not invited]
    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  2020/11
  • 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  [Not invited]
    細矢直基, 吉田侑樹, 前田真吾, 梶原逸朗
    Dynamics and Design Conference 2020  2020/09
  • 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  [Not invited]
    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  2020/09
  • 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  [Not invited]
    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  2020/09
  • 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  [Not invited]
    比留田稔樹, 細矢直基, 前田真吾, 梶原逸朗
    Dynamics and Design Conference 2020  2020/09
  • 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  [Not invited]
    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  2019/12
  • 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  [Not invited]
    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  2019/11
  • 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  [Not invited]
    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  2019/11
  • 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  [Not invited]
    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  2019/11
  • 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  [Not invited]
    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  2019/09
  • 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  [Not invited]
    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  2019/09
  • 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  [Not invited]
    荒井那由他, 高橋健太郎, 細矢直基, 梶原逸朗
    Dynamics and Design Conference 2019  2019/08
  • 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  [Not invited]
    米沢安成, 米沢平成, 梶原逸朗
    Dynamics and Design Conference 2019  2019/08
  • 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  [Not invited]
    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  2019/08
  • 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  [Not invited]
    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  2019/08
  • 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  [Not invited]
    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  2018/12
  • 任意構造物の制振を可能とするモデルフリー振動制御  [Not invited]
    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  2018/11
  • 実験モード解析による「太陽のタマゴ」の硬さ評価  [Not invited]
    細矢直基, 出西勇気, 高橋健太郎, 梶原逸朗
    Dynamics and Design Conference 2018  2018/08
  • 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)  [Not invited]
    平原隼人, 梶原逸朗, 細矢直基, 前田真吾
    Dynamics and Design Conference 2018  2018/08
  • 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  [Not invited]
    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  2018/08
  • 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  [Not invited]
    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  2018/03
  • 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  [Not invited]
    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  2017/11
  • 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）  [Not invited]
    奥村洋平, 細矢直基, 神田淳, 岩﨑紗綾, 梶原逸朗
    Dynamics and Design Conference 2017  2017/08
  • 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  [Not invited]
    小田一心, 梶原逸朗, 細矢直基
    Dynamics and Design Conference 2017  2017/08
  • 非線形性を有する自動車駆系の加速度制御  [Not invited]
    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  2017/08
  • 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  [Not invited]
    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  2017/08
  • 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  [Not invited]
    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  2016/10
  • 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  [Not invited]
    北畠茂幹, 梶原逸朗, 有坂寿洋
    Dynamics and Design Conference 2016  2016/08
  • 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  [Not invited]
    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  2016/08
  • 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  [Not invited]
    秋田涼佑, 梶原逸朗, 細矢直基
    Dynamics and Design Conference 2016  2016/08
  • 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  [Not invited]
    神田淳, 細矢直基, 梶原逸朗
    可視化情報全国講演(京都2015)  2015/10
  • 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  [Not invited]
    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  2015/09
  • 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）  [Not invited]
    古谷圭一郎, 石塚真一, 梶原逸朗
    Dynamics and Design Conference 2015  2015/08
  • MEMS加速度計を用いたモデルフリー振動制御手法  [Not invited]
    伊藤陸, 梶原逸朗, 金堂雅彦
    Dynamics and Design Conference 2015  2015/08
  • 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  [Not invited]
    柴田真太朗, 張月琳, 梶原逸朗, 細矢直基
    Dynamics and Design Conference 2015  2015/08
  • 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  [Not invited]
    佐藤周也, 梶原逸朗, 金堂雅彦, 川野順一
    Dynamics and Design Conference 2015  2015/08
  • 圧電フィルムを用いた膜構造のアクティブ振動制御  [Not invited]
    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  2015/05
  • 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  [Not invited]
    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  2015/01
  • 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  [Not invited]
    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  2014/12
  • 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  [Not invited]
    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  2014/11
  • 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  [Not invited]
    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  2014/11
  • 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  [Not invited]
    石塚真一, 佐藤淳一, 梶原逸朗
    第57回自動制御連合講演会  2014/11
  • 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)  [Not invited]
    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  2014/08
  • 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  [Not invited]
    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  2014/08
  • 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）  [Not invited]
    新里淳, 梶原逸朗, Feblil Huda, 細矢直基
    Dynamics and Design Conference 2014  2014/08
  • スマート構造を用いたＰＣ筐体のアクティブ振動制御  [Not invited]
    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  2014/03
  • 有限要素解析による肝臓モデルのMREシミュレーション  [Not invited]
    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  2014/01
  • 同時摂動確率近似によるモデルフリー適応PID制御  [Not invited]
    石塚真一, 梶原逸朗
    第56回自動制御連合講演会  2013/11
  • 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  [Not invited]
    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  2013/11
  • アクティブマウントによるHDDシステムの外部振動遮断  [Not invited]
    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  2013/11
  • 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  [Not invited]
    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  2013/08
  • 修正MPCによるディーゼルエンジンのEGR-VNT協調制御  [Not invited]
    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  2013/08
  • 粘弾性体の有限要素解析によるMREシミレーション  [Not invited]
    富田直, 鈴木逸人, 梶原逸朗, 但野茂
    Dynamics and Design Conference 2013  2013/08
  • パルスレーザーを用いた高分子材料の振動試験  [Not invited]
    馬場駿, 細矢直基, 前田真吾, 梶原逸朗
    Dynamics and Design Conference 2013  2013/08
  • 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  [Not invited]
    新里淳, 梶原逸朗, 細矢直基, Feblil Huda
    Dynamics and Design Conference 2013  2013/08
  • 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  [Not invited]
    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  2013/03
  • 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  [Not invited]
    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  2013/03
  • 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  [Not invited]
    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  2012/12
  • 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  [Not invited]
    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  2012/12
  • 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)  [Not invited]
    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  2012/11
  • 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)  [Not invited]
    朱艶, 梶原逸朗, 細矢直基
    第55回自動制御連合講演会  2012/11
  • 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  [Not invited]
    中嶋渉, 梶原逸朗
    第55回自動制御連合講演会  2012/11
  • micro-MRIによる高分子ゲルの3次元MRE画像  [Not invited]
    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  2012/10
  • 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  [Not invited]
    渡邉一希, 本田真也, 成田吉弘, 梶原逸朗
    Dynamics and Design Conference 2012  2012/09
  • 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  [Not invited]
    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  2012/09
  • 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  [Not invited]
    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  2012/09
  • 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  [Not invited]
    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  2012/09
  • 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  [Not invited]
    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  2012/09
  • mico-MRIによる2層アガロースゲルのMRE画像  [Not invited]
    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  2012/09
  • 高分子ゲルのMRE画像に対する加振条件  [Not invited]
    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  2012/01
  • 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  [Not invited]
    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  2011/12
  • 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  [Not invited]
    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  2011/10
  • 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  [Not invited]
    朱艶, 中村哲司, 梶原逸朗
    Dynamics and Design Conference 2011  2011/09
  • 非接触レーザー加振システムによる膜構造の振動計測  [Not invited]
    梶原逸朗, 小原賢也
    Dynamics and Design Conference 2011  2011/09
  • 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  [Not invited]
    小坂亙, 本田真也, 成田吉弘, 梶原逸朗
    Dynamics and Design Conference 2011  2011/09
  • 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  [Not invited]
    宮本大資, 梶原逸朗, 細矢直基
    Dynamics and Design Conference 2011  2011/09
  • 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  [Not invited]
    矢作修一, 細矢直基, 梶原逸朗
    Dynamics and Design Conference 2011  2011/09
  • 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  [Not invited]
    永田将希, 細矢直基, 梶原逸朗
    Dynamics and Design Conference 2011  2011/09
  • 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  [Not invited]
    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  2011/06
  • 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  [Not invited]
    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  2011/06
  • 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  [Not invited]
    朱艶, 中村哲司, 梶原逸朗
    IIP2011情報・知能・精密機器部門講演会  2011/03
  • 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  [Not invited]
    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  2011/03
  • 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  [Not invited]
    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  2011/03
  • 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  [Not invited]
    西埜亮太, 小原賢也, 梶原逸朗
    第53回自動制御連合講演会  2010/11
  • 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  [Not invited]
    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  2010/11
  • スマート複合材料の振動制御に関する統合最適化  [Not invited]
    本田真也, 成田吉弘, 梶原逸朗
    第23回計算力学講演会  2010/09
  • 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  [Not invited]
    中村哲司, 梶原逸朗, 有坂寿洋
    第23回計算力学講演会  2010/09
  • 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  [Not invited]
    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  2010/09
  • 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  [Not invited]
    細矢直基, 梶原逸朗, 細川恭彦
    Dynamics and Design Conference 2010  2010/09
  • 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  [Not invited]
    櫻井努, 梶原逸朗, 原田宏幸, 新井浩成
    Dynamics and Design Conference 2010  2010/09
  • 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  [Not invited]
    中村哲司, 梶原逸朗, 有坂寿洋, 高橋真史
    Dynamics and Design Conference 2010  2010/09
  • SMAアクチュエータを用いた水中推進ロボット  [Not invited]
    原田宏幸, 梶原逸朗, 黒川貴裕
    Dynamics and Design Conference 2010  2010/09
  • 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  [Not invited]
    細川恭彦, 細矢直基, 梶原逸朗
    Dynamics and Design Conference 2010  2010/09
  • 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  [Not invited]
    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  2010/03
  • セミアクティブサスペンションによる車両の振動制御  [Not invited]
    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  2010/02
  • 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  [Not invited]
    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  2009/12
  • HDD高密度化のための振動制御と革新的振動計測技術  [Not invited]
    梶原逸朗
    イノベーションジャパン2009 －大学見本市  2009/09
  • 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）  [Not invited]
    細矢直基, 反町仁, 梶原逸朗, 原口大輔
    Dynamics and Design Conference 2009  2009
  • レーザー双方向通信によるマイクロ移動体の遠隔制御  [Not invited]
    梶原逸朗, 中野孝亮
    Dynamics and Design Conference 2009  2009
  • 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  [Not invited]
    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
  • ILQ設計に基づくディーゼルエンジンのEGR-VNT協調制御  [Not invited]
    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
  • 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  [Not invited]
    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
  • 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  [Not invited]
    梶原逸朗, 内山敏夫, 有坂寿洋
    Dynamics and Design Conference 2008  2008
  • 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  [Not invited]
    高橋真史, 内山敏夫, 梶原逸朗, 有坂寿洋
    Dynamics and Design Conference 2008  2008
  • 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  [Not invited]
    中野孝亮, 小幡倫世, 梶原逸朗
    Dynamics and Design Conference 2008  2008
  • 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  [Not invited]
    細矢直基, 梶原逸朗
    Dynamics and Design Conference 2008  2008
  • 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  [Not invited]
    梶原逸朗, 土屋亮, 石塚真一
    第21回計算力学講演会  2008
  • HDDにおけるヘッド機構のスマート構造化と最適設計  [Not invited]
    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
  • Gain-scheduled control of smart structures with dynamic characteristic variation  [Not invited]
    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  [Not invited]
    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
  • 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  [Not invited]
    小野仁章, 梶原逸朗
    Dynamics and Design Conference 2007  2007
  • レーザーエネルギー伝送による小型移動体の遠隔駆動  [Not invited]
    中野孝亮, 大北哲也, 梶原逸朗
    Dynamics and Design Conference 2007  2007
  • レーザーを用いた新しい加振実験方法  [Not invited]
    小幡倫世, 梶原逸朗
    Dynamics and Design Conference 2007  2007
  • 正実性を利用したスマート構造による振動制御法  [Not invited]
    片岡隆仁, 粟生真行, 梶原逸朗
    Dynamics and Design Conference 2007  2007
  • Remote Control of Laser-Driven Micro-Vehicles  [Not invited]
    4th International Symposium on Beamed Energy Propulsion  2006
  • Optimization of vibration control system for smart structures with disturbance characteristic variation  [Not invited]
    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  [Not invited]
    小野仁章, 梶原逸朗
    Dynamics and Design Conference 2006  2006
  • マイクロ移動体のための光学システムの開発  [Not invited]
    大北哲也, 梶原逸朗
    Dynamics and Design Conference 2006  2006
  • 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  [Not invited]
    土屋亮, 梶原逸朗
    日本機械学会2006年度年次大会  2006
  • 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  [Not invited]
    小野仁章, 梶原逸朗
    第49回自動制御連合講演会  2006
  • 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  [Not invited]
    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
  • Suppression of Combustion Noise and Combustion Oscillation by Thermo-Acoustic Active Control Using Secondary Flame  [Not invited]
    ASME Turbo Expo 2005  2005
  • Remote Control of Laser-Driven Micro-Vehicles  [Not invited]
    4th International Symposium on Beamed Energy Propulsion  2005
  • Efficiency of Air Injection on Stability and Emission Controls in Premixed Combustion  [Not invited]
    20th International Colloquium on the Dynamics of Explosions and Reactive Systems  2005
  • Multidisciplinary Design Optimization of Smart Structures for Vibration and Sound Suppression  [Not invited]
    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  [Not invited]
    土屋亮, 梶原逸朗
    Dynamics and Design Conference 2005  2005
  • レーザーによる移動体の遠隔制御に関する研究  [Not invited]
    大北哲也, 星野健太郎, 梶原逸朗
    Dynamics and Design Conference 2005  2005
  • スマート構造の複合領域最適化による振動・騒音の抑制  [Not invited]
    小野仁章, 梶原逸朗, 石塚真一
    Dynamics and Design Conference 2005  2005
  • 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  [Not invited]
    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
  • Multidisciplinary Design of Actuator Array and Adaptive Control System for Smart Structures  [Not invited]
    2004
  • Integrated Actuator/Control Design of Smart Pantograph Mechanism for Vibration Suppression  [Not invited]
    2004
  • Integrated Design of Mechanism and Control System for Smart Structures  [Not invited]
    2004
  • Multidisciplinary Optimization of Smart Structure with Characteristic Variation for Vibration Suppression  [Not invited]
    2004
  • Development of Laser Propulsion and Tracking System for Laser-Driven Micro-Airplane  [Not invited]
    2004
  • Tracking Control for Laser-Driven Micro-Airplane  [Not invited]
    2004
  • マイクロ飛行機のためのレーザー推進／追尾システム  [Not invited]
    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
  • 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  [Not invited]
    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
  • パンタグラフ機構のスマート構造化による振動制御  [Not invited]
    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
  • 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  [Not invited]
    土屋亮, 梶原逸朗
    日本機械学会2004年度年次大会  2004
  • 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  [Not invited]
    岩垂素子, 梶原逸朗, 堀江三喜男
    Dynamics and Design Conference 2004  2004
  • 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  [Not invited]
    梶原逸朗, 矢部孝
    Dynamics and Design Conference 2004  2004
  • 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  [Not invited]
    土屋亮, 梶原逸朗
    Dynamics and Design Conference 2004  2004
  • 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  [Not invited]
    梶原逸朗, 大橋史武
    第47回自動制御連合講演会  2004
  • 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  [Not invited]
    土屋亮, 梶原逸朗
    第6回最適化シンポジウム  2004
  • Development of Laser Propulsion and Tracking System for Laser-Driven Micro-Airplane  [Not invited]
    2003
  • Control of Wing for Micro-Airplane with Smart Material and Laser  [Not invited]
    2003
  • Optimization of Smart Structure For Realizing High Controllability  [Not invited]
    2003
  • Optimal Design of Smart Carriage Arm in Magnetic Disk Drive for Vibration Suppression  [Not invited]
    2003
  • 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  [Not invited]
    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
  • 制御性を考慮したスマート構造の位相・形状最適化  [Not invited]
    梶原逸朗, 大森隆広
    Dynamics and Design Conference 2003  2003
  • 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  [Not invited]
    大橋史武, 梶原逸朗, 有坂寿洋
    Dynamics and Design Conference 2003  2003
  • 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  [Not invited]
    岩垂素子, 大橋史武, 梶原逸朗
    Dynamics and Design Conference 2003  2003
  • 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  [Not invited]
    石川博康, 梶原逸朗, 古谷俊輔, 矢部孝
    Dynamics and Design Conference 2003  2003
  • 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  [Not invited]
    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
  • Hybrid Control of Motion and Vibration for Smart Flexible-Link Mechanism  [Not invited]
    Nishidome, C, Kajiwara, I
    SICE Annual Conference 2002  2002
  • Simultaneous Design of Mechanism and Control System for Smart Strucutres (Optimization of Piezoelectric Placement and Application to Magnetic Disk Drive)  [Not invited]
    2002
  • Design of Shape and Control System for Micro-Airplane Development  [Not invited]
    Ishikawa, H, Kajiwara, I, Yabe, T
    SICE Annual Conference 2002  2002
  • Laser-driven vehicles: from inner space to outer space  [Not invited]
    2002
  • Motion and Vibration Control of Flexible-Link Mechanism with Smart Structure  [Not invited]
    2002
  • Position and Force Control of 2-Link Manipulator Using Mixed H2/H∞ Control  [Not invited]
    2002
  • 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)  [Not invited]
    梶原逸朗, 上原学, 大森隆広
    Dynamics and Design Conference 2002  2002
  • 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  [Not invited]
    大森隆広, 梶原逸朗, 松井勉
    Dynamics and Design Conference 2002  2002
  • スマート構造における機構系と制御系の同時最適化  [Not invited]
    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
  • 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－  [Not invited]
    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
  • 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  [Not invited]
    大森隆広, 上原学, 梶原逸朗
    Dynamics and Design Conference 2001  2001
  • 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  [Not invited]
    梶原逸朗, 月成俊介, 吉村卓也
    Dynamics and Design Conference 2001  2001
  • 圧電フィルムによるOA機器の計測と制御  [Not invited]
    江連勝彦, 猿渡克巳, 梶原逸朗, 森厚夫
    Dynamics and Design Conference 2001  2001
  • スマート構造における計測と制御  [Not invited]
    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
  • 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  [Not invited]
    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
  • 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)  [Not invited]
    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
  • 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  [Not invited]
    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
  • 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  [Not invited]
    梶原逸朗, 榊原範人, 長松昭男
    Dynamics and Design Conference 2000  2000
  • Shape Optimization of Micro Air Vehicles Considering Stability and Controllability  [Not invited]
    Kajiwara, I, Haftka, R. T
    第48回理論応用力学講演会  1999
  • 振動低減のための構造系と制御系の統合設計法  [Not invited]
    梶原逸朗, 長松昭男
    Dynamics and Design Conference ’99  1999
  • フレキシブルリンク機構における振動と運動の制御  [Not invited]
    榊原範人, 梶原逸朗, 長松昭男
    1999年度システム部門講演  1999
  • スマート構造における形状と制御の同時最適化  [Not invited]
    梶原逸朗, 榊原範人, 長松昭男
    1999年度システム部門講演  1999
  • Simultaneous Optimum Design of Structure and Control System  [Not invited]
    Kajiwara, I
    計測自動制御学会第３７回学術講演会予稿集  1998
  • 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  [Not invited]
    松永義弘, 小池関也, 下嶋浩, 梶原逸朗
    Dynamics and Design Conference ’98  1998
  • Simultaneous Optimum Design of Shape and Control System for Micro Air Vehicles  [Not invited]
    Kajiwara, I, Haftka, R. T
    第76期日本機械学会全国大会講演会  1998
  • 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  [Not invited]
    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
  • 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  [Not invited]
    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
  • 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）  [Not invited]
    梶原逸朗, 鎌田慶宣, 長松昭男
    Dynamics and Design Conference ’97  1997
  • 防振ハンドルの最適設計に関する研究  [Not invited]
    Hyou Eiko, 背戸一登, 土井文夫
    Dynamics and Design Conference ’97  1997
  • 位置決め制御機構における構造と制御の統合最適化  [Not invited]
    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
  • 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）  [Not invited]
    梶原逸朗, 長松昭男, 松永義弘
    Dynamics and Design Conference ’96  1996
  • 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  [Not invited]
    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
  • 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  [Not invited]
    梶原逸朗, 長松昭男
    第2回最適化シンポジウム  1996
  • 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  [Not invited]
    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
  • 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  [Not invited]
    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
  • 振動問題における構造物の形状最適設計  [Not invited]
    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
  • 固有振動数を高める構造物の形状最適化手法  [Not invited]
    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
  • 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  [Not invited]
    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
  • 高周波遷移領域のおける振動評価  [Not invited]
    梶原逸朗, 高橋直樹, 長松昭男
    Dynamics and Design Conference ’95  1995
  • 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）  [Not invited]
    梶原逸朗, 佐々木康貴, 長松昭男
    Dynamics and Design Conference ’95  1995
  • 振動問題における結合条件の感度解析  [Not invited]
    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
  • 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  [Not invited]
    辻岡一明, 梶原逸朗, 浅井勝彦, 長松昭男
    Dynamics and Design Conference ’94  1994
  • 振動問題における構造物の形状最適設計  [Not invited]
    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
  • 構造系と 制御系の同時最適設計  [Not invited]
    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
  • 構造系と出力フィードバック制御系の同時最適設計  [Not invited]
    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
  • 感度解析による構造系と制御系の最適設計  [Not invited]
    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
  • 特性行列同定法に基づく最適制御系の設計法  [Not invited]
    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
  • 共振点と反共振点の感度を用いた構造物の最適化方法  [Not invited]
    梶原逸朗
    第１回環境工学総合シンポジウム講  1991
  • 共振点消去の方法と光サーボ系の最適設計  [Not invited]
    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

Association Memberships

  • THE VISUALIZATION SOCIETY OF JAPAN   日本機械学会   自動車技術会   計測自動制御学会   American Society of Mechanical Engineers   Astronautics   American Institute of Aeronautics and   

Research Projects

  • Japan Society for the Promotion of Science：Grant-in-Aid for Scientific Research
    Date (from‐to) : 2019/04 -2022/03 
    Author : 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：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2015/04 -2018/03 
    Author : 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.
  • Dynamic characteristic evaluation and diagnosis of mechanical / biological systems by the non-contact laser vibrating system
    Grant-in-Aid for Scientific Research
    Date (from‐to) : 2016 -2018 
    Author : KAJIWARA ITSURO
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2014/04 -2017/03 
    Author : 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：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2012/04 -2014/03 
    Author : 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 Scientific Research
    Date (from‐to) : 2010 -2012 
    Author : 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：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2008 -2012 
    Author : 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：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2010 -2011 
    Author : 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.
  • Innovative vibration test method based on noncontact excitation via laser ablation
    JST A-STEP (Feasibility Study)
    Date (from‐to) : 2009 -2010 
    Author : KAJIWARA ITSURO
  • Develoment of large capacity hard disk drive using smart structure techonogies
    JST SEEDS TEST (B)
    Date (from‐to) : 2008 -2008 
    Author : KAJIWARA ITSURO
  • Develoment of large capacity hard disk drive using smart structure techonogies
    JST SEEDS TEST
    Date (from‐to) : 2007 -2007 
    Author : KAJIWARA ITSURO
  • Japan Society for the Promotion of Science：Grant-in-Aid for Scientific Research
    Date (from‐to) : 2006 -2007 
    Author : 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
    Date (from‐to) : 2002 -2004 
    Author : 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：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2001 -2003 
    Author : 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
  • 日本学術振興会：Grant-in-Aid for Scientific Research
    Date (from‐to) : 2002 -2002 
    Author : 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：Grant-in-Aid for Scientific Research
    Date (from‐to) : 2000 -2001 
    Author : 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：科学研究費助成事業
    Date (from‐to) : 1998 -1999 
    Author : 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：科学研究費助成事業
    Date (from‐to) : 1997 -1997 
    Author : 梶原 逸朗
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 1996 -1996 
    Author : 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.
  • 日本学術振興会：Grant-in-Aid for Scientific Research
    Date (from‐to) : 1996 -1996 
    Author : 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：科学研究費助成事業
    Date (from‐to) : 1995 -1995 
    Author : 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：Grant-in-Aid for Scientific Research
    Date (from‐to) : 1995 -1995 
    Author : 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：Grant-in-Aid for Scientific Research
    Date (from‐to) : 1994 -1994 
    Author : 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。
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 1993 -1994 
    Author : 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.
  • 日本学術振興会：Grant-in-Aid for Scientific Research
    Date (from‐to) : 1993 -1993 
    Author : 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：Grant-in-Aid for Scientific Research
    Date (from‐to) : 1992 -1992 
    Author : KAJIWARA ITSURO
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 1991 -1992 
    Author : 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.
  • 日本学術振興会：Grant-in-Aid for Scientific Research
    Date (from‐to) : 1991 -1991 
    Author : KAJIWARA ITSURO

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