Researcher Profile and Settings

Master

Affiliation (Master)

• Faculty of Information Science and Technology　Systems Science and Informatics　Informatics for System Creation

Affiliation (Master)

• Faculty of Information Science and Technology　Systems Science and Informatics　Informatics for System Creation

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Profile and Settings

Profile and Settings

• Name (Japanese)

  Yamashita

• Name (Kana)

  Yuh

• Name

  200901089891188357

Alternate Names

http://stlab.ssi.ist.hokudai.ac.jp/yuhyama/
http://stlabwww.ssi.ist.hokudai.ac.jp/yuhyama/

Achievement

Research Interests

• Nonlinear Control Theory   知能機械学・機械システム   制御工学   

Research Areas

• Informatics / Robotics and intelligent systems
• Informatics / Mechanics and mechatronics
• Manufacturing technology (mechanical, electrical/electronic, chemical engineering) / Control and systems engineering

Research Experience

• 2019/04 - Today Hokkaido University Division of Systems Science and Informatics, Faculty of Information Science and Technology Professor

Awards

• 2018/06 The Institute of Electronics, Information and Communication Engineers of JAPAN 2017 Best Paper Award
   Linear Quadratic Regulator with Decentralized Event-Triggering 

  受賞者: K. Nakajima;K. Kobayashi;Y. Yamashita

Published Papers

• Model Predictive Control of Spatially Distributed Systems with Spatio-Temporal Logic Specifications

  Ikkei Komizu, Koichi Kobayashi, Yuh Yamashita

  Computation 12 (10) 196 - 196 2024/09/30 

  In this paper, for spatially distributed systems, we propose a new method of model predictive control with spatio-temporal logic specifications. We formulate the finite-time control problem with specifications described by SSTLf (signal spatio-temporal logic over finite traces) formulas. In the problem formulation, the feasibility is guaranteed by representing control specifications as a penalty in the cost function. Time-varying weights in the cost function are introduced to satisfy control specifications as well as possible. The finite-time control problem can be written as a mixed integer programming (MIP) problem. According to the policy of model predictive control (MPC), the control input can be generated by solving the finite-time control problem at each discrete time. The effectiveness of the proposed method is presented through a numerical example.
• A BDD-Based Approach to Finite-Time Control of Boolean Networks

  Fuma MOTOYAMA, Koichi KOBAYASHI, Yuh YAMASHITA

  IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E107.A (5) 793 - 798 0916-8508 2024/05/01
• Lyapunov-based approach to event-triggered control with self-triggered sampling

  Shota Nakayama, Koichi Kobayashi, Yuh Yamashita

  Advanced Robotics 38 (9-10) 603 - 609 0169-1864 2024/02/28
• On reward distribution in reinforcement learning of multi-agent surveillance systems with temporal logic specifications

  Keita Terashima, Koichi Kobayashi, Yuh Yamashita

  Advanced Robotics 2024/02/14
• Online Optimization of Pickup and Delivery Problem Considering Feasibility

  Ryo Matsuoka, Koichi Kobayashi, Yuh Yamashita

  Future Internet 2024/02
• A BDD-Based Approach to Model Reduction of Boolean Networks

  Fuma Motoyama, Koichi Kobayashi, Yuh Yamashita

  IEEE Transactions on Control of Network Systems 2024
• Reinforcement Learning for Multi-Agent Systems with Temporal Logic Specifications

  Keita TERASHIMA, Koichi KOBAYASHI, Yuh YAMASHITA

  IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E107-A (1) 31 - 37 0916-8508 2024/01 [Refereed]
  
• Multi-Agent Surveillance Based on Travel Cost Minimization

  Kyohei MURAKATA, Koichi KOBAYASHI, Yuh YAMASHITA

  IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E107-A (1) 25 - 30 0916-8508 2024/01 [Refereed]
  
• Finite-Time Control of Boolean Networks Using Binary Decision Diagrams

  Fuma Motoyama, Koichi Kobayashi, Yuh Yamashita

  Proc. SICE Annual Conference 2023 145 - 148 2023/09 [Refereed]
  
• Redesign of Control Lyapunov Functions of Nonlinear Systemswith Symmetry under Feedbacks

  Yuh Yamashita, Koichi Kobayashi

  Proc. SICE Annual Conference 2023 411 - 414 2023/09 [Refereed]
  
• Lyapunov Function-Based Approach to Event-Triggered Control with Self-Triggered Sampling

  Nakayama Shota, Kobayashi Koichi, Yamashita Yuh

  Proc. of the 2023 International Symposium on Nonlinear Theory and Its Application 467 - 470 2023/09 [Refereed]
  
• LMI-Based Design of Structured Block-Sparse Output Feedback Controllers for Sensor and Actuator Networks

  Yuta Kawano, Koichi Kobayashi, Yuh Yamashita

  Preprints of the 22nd IFAC World Congress 1481 - 1484 2023/07 [Refereed]
  
• Reinforcement Learning for Multi-Agent Systems with Temporal Logic Specifications

  Keita Terashima, Koichi Kobayashi, Yuh Yamashita

  Preprints of the 22nd IFAC World Congress 1509 - 1512 2023/07 [Refereed]
  
• Vehicle Platooning at Intersection Based on Self-Triggered Pinning Consensus Control

  Ayaka Tanaka, Koichi Kobayashi, Yuh Yamashita

  Preprints of the 22nd IFAC World Congress 5026 - 5028 2023/07 [Refereed]
  
• Automatic Generation of Control Lyapunov Functions for Vehicle Guidance on Complex Paths

  Yuh Yamashita, Wataru Hashimoto, Koichi Kobayashi

  IFAC-PapersOnLine 56 (2) 8036 - 8041 2405-8963 2023/07 [Refereed]
  
• Design of reduced-order and pinning controllers for probabilistic Boolean networks using reinforcement learning

  Michiaki Takizawa, Koichi Kobayashi, Yuh Yamashita

  Applied Mathematics and Computation 457 128211 - 128211 0096-3003 2023/07 [Refereed]
  
• Multi-Agent Reinforcement Learning Based on Event-Based Communication

  Hiroki Sunai, Koichi Kobayashi, Yuh Yamashita

  Proc. of the 38th International Technical Conference on Circuits/Systems, Computers, and Communications 2023/06
• Notion of Opacity and Its Verification for Discrete-Time Piecewise Linear Systems

  Taiga Matsumae, Koichi Kobayashi, Yuh Yamashita

  Proc. of the 38th International Technical Conference on Circuits/Systems, Computers, and Communications 2023/06 [Refereed]
  
• Fixed Point Preserving Model Reduction of Boolean Networks Focusing on Complement and Absorption Laws

  Fuma Motoyama, Koichi Kobayashi, Yuh Yamashita

  IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences E106-A (5) 721 - 728 2023/05 [Refereed]
  
• Detection of False Data Injection Attacks in Distributed State Estimation of Power Networks

  Sho Obata, Koichi Kobayashi, Yuh Yamashita

  IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences E106-A (5) 729 - 735 0916-8508 2023/05 [Refereed]
  
• Block sparse design of distributed controllers for dynamical network systems

  Ryosuke Adachi, Yuh Yamashita, Koichi Kobayashi

  International Journal of Robust and Nonlinear Control 33 (1) 49 - 66 1049-8923 2023/01/10 [Refereed]
   

  This study proposes a controller design method based on block sparse optimization for dynamical network systems. The objective of the controller is to stabilize dynamical network systems with a given convergence rate. The block sparse optimization minimizes the number of controlled nodes. This study is unique in that the structure of the controller is constrained by the network topology of the system. Additionally, the proposed design problem is separable in terms of the distributed optimization over networks. The proposed method is applicable to controller design for the pinning control of consensus systems and the optimal vaccine allocation for epidemic spreading processes.
• Asymptotic stabilization with group‐wise sparse input based on control Lyapunov function approach

  Yuh Yamashita, Kiminori Sakano, Koichi Kobayashi

  International Journal of Robust and Nonlinear Control 33 (1) 35 - 48 1049-8923 2023/01/10 [Refereed]
  
• Passivity‐based control of nonlinear active dynamic vibration absorber

  Sheng Hao, Yuh Yamashita, Koichi Kobayashi

  International Journal of Robust and Nonlinear Control 33 (5) 3247 - 3266 1049-8923 2023/01/06 [Refereed][Not invited]
  
• Decentralized Event-Triggered Output Feedback Control for Cyber-Physical Systems

  Koichi Kitamura, Koichi Kobayashi, Yuh Yamashita

  Proc. of the Joint Symposium of AROB 28th 2023, ISBC 8th 2023, and SWARM 6th 2023 2023/01 [Refereed]
  
• LMI-Based Design of Structured Sparse Output Feedback Controllers

  Yuta Kawano, Koichi Kobayashi, Yuh Yamashita

  Proc. of the Joint Symposium of AROB 28th 2023, ISBC 8th 2023, and SWARM 6th 2023 2023/01 [Refereed]
  
• Output Feedback Ultimate Boundedness Control with Decentralized Event-Triggering

  Koichi KITAMURA, Koichi KOBAYASHI, Yuh YAMASHITA

  IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences 0916-8508 2023 [Refereed]
  
• Virtual merge and split at intersection for vehicle platooning based on self-triggered pinning consensus control

  Ayaka Tanaka, Koichi Kobayashi, Yuh Yamashita

  Advanced Robotics 37 (1) 1 - 10 0169-1864 2023/01 [Refereed]
  
• Output Feedback Ultimate Boundedness Control with Decentralized Event-Triggering

  Koichi Kitamura, Koichi Kobayashi, Yuh Yamashita

  Proc. of 2022 International Symposium on Nonlinear Theory and Its Applications 2022/12 [Refereed]
  
• Blockchain-Based Optimization of Distributed Energy Management Systems with Real-Time Demand Response

  Daiki OGAWA, Koichi KOBAYASHI, Yuh YAMASHITA

  IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E105-A (11) 1478 - 1485 0916-8508 2022/11 [Refereed]
  
• On Initial Locations, Feasibility, and Performance in Multi-Agent Surveillance Systems

  Kyohei Murakata, Koichi Kobayashi, Yuh Yamashita

  Proc. of 2022 IEEE 11th Global Conference on Consumer Electronics (GCCE) 2022/10 [Refereed]
  
• Control of Multi-Agent Surveillance Systems Using Reinforcement Learning

  Keita Terashima, Koichi Kobayashi, Yuh Yamashita

  Proc. of the SICE Annual Conference 2022 ThB05.4  2022/09 [Refereed]
  
• Online Optimization of Pickup and Delivery Problem with Fuel Constraints

  Ryo Matsuoka, Koichi Kobayashi, Yuh Yamashita

  Proc. of the International Technical Conference on Circuits/Systems, Computers, and Communications 2022 2022/07 [Refereed]
  
• Sensor Scheduling-Based Detection of False Data Injection Attacks in Power System State Estimation

  Sho OBATA, Koichi KOBAYASHI, Yuh YAMASHITA

  IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E105-A (6) 1015 - 1019 0916-8508 2022/06 [Refereed][Not invited]
  
• LMI-Based Design of Output Feedback Controllers with Decentralized Event-Triggering

  Koichi KITAMURA, Koichi KOBAYASHI, Yuh YAMASHITA

  IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E105-A (5) 816 - 822 0916-8508 2022/05 [Refereed][Not invited]
  
• Self-Triggered Consensus Approach to Vehicle Platooning at Intersection

  Ayaka Tanaka, Koichi Kobayashi, Yuh Yamashita

  Proc. of IEEE 40th International Conference on Consumer Electronics 2022/01 [Refereed][Not invited]
  
• Robust passivity‐based control design for active nonlinear suspension system

  Sheng Hao, Yuh Yamashita, Koichi Kobayashi

  International Journal of Robust and Nonlinear Control 32 (1) 373 - 392 1049-8923 2022/01 [Refereed][Not invited]
  
• Asymptotic stabilization of nonlinear systems with convex-polytope input constraints by continuous input

  Yuh Yamashita, Ryosuke Matsukizono, Koichi Kobayashi

  Automatica 138 110032 - 110032 0005-1098 2021/11 [Refereed][Not invited]
  
• Distributed Optimal Estimation with Scalable Communication Cost

  Ryosuke Adachi, Yuh Yamashita, Koichi Kobayashi

  IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences E104-A (11) 1470 - 1476 0916-8508 2021/11 [Refereed][Not invited]
  
• On Detection of False Data Injection Attacks in Distributed State Estimation of Power Networks

  Sho Obata, Koichi Kobayashi, Yuh Yamashita

  2021 IEEE 10th Global Conference on Consumer Electronics (GCCE) 472 - 473 2021/10/12 [Refereed][Not invited]
  
• A Graph-Theoretic Approach to Model Reduction of Boolean Networks

  Motoyama, Fuma, Kobayashi, Koichi, Yamashita, Yuh

  Proc. of the SICE Annual Conference 2021 952 - 955 2021/09 [Refereed][Not invited]
  
• Pinning Stabilization of Probabilistic Boolean Networks Using Reinforcement Learning

  Takizawa, Michiaki, Kobayashi, Koichi, Yamashita, Yuh

  Proc. of the SICE Annual Conference 2021 942 - 945 2021/09 [Refereed][Not invited]
  
• Optimal Control Considering Standby Power of Actuators

  Kunitsugu, Yohei, Yamashita, Yuh, Kobayashi, Koichi

  Proc. of the SICE Annual Conference 2021 467 - 470 2021/09 [Refereed][Not invited]
  
• LMI-Based Design of Decentralized Event-Triggered Control Over Sensor and Actuator Networks

  Kitamura, Koichi, Kobayashi, Koichi, Yamashita, Yuh

  Proc. of the SICE Annual Conference 2021 457 - 460 2021/09 [Refereed][Not invited]
  
• Construction of ISS Lyapunov functions for Hamiltonian systems with multiple disturbances

  Sheng Hao, Yuh Yamashita, Koichi Kobayashi

  IFAC-PapersOnLine (Special Issue for Proceedings of 3rd IFAC Conference on Modelling, Identification and Control of Nonlinear Systems) 54 (14) 281 - 286 2405-8963 2021/09 [Refereed][Not invited]
  
• Decentralized Event-Triggered Control of Discrete-Time Linear Systems via Output Feedback

  Koichi Kitamura, Koichi Kobayashi, Yuh Yamashita

  IEEE International Symposium on Industrial Electronics 2021- 2021/06/20 

  In this paper, event-triggered control over a sensor network is studied as one of the control methods of cyber-physical systems. Event-triggered control is a method that communications occur only when the measured value is widely changed. In the proposed method, by solving an LMI (linear matrix inequality) feasibility problem, we derive an event-triggered output feedback controller such that the closed-loop system is asymptotically stable. First, the problem formulation is given. Next, the control problem is reduced to an LMI feasibility problem. Finally, the proposed method is demonstrated by a numerical example.
• Distributed Observer Design on Sensor Networks with Random Communication

  Yuh Yamashita, Haruka Sumita, Ryosuke Adachi, Koichi Kobayashi

  IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E104-A (3) 613 - 621 0916-8508 2021/03 [Refereed][Not invited]
   

  This paper proposes a distributed observer on a sensor network, where communication on the network is randomly performed. This work is a natural extension of Kalman consensus filter approach to the cases involving random communication. In both bidirectional and unidirectional communication cases, gain conditions that guarantee improvement of estimation error convergence compared to the case with no communication are obtained. The obtained conditions are more practical than those of previous studies and give appropriate cooperative gains for a given communication probability. The effectiveness of the proposed method is confirmed by computer simulations.
• Uniformly Ultimate Boundedness Control with Decentralized Event-Triggering

  Koichi Kobayashi, Kyohei Nakajima, Yuh Yamashita

  IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E104-A (2) 455 - 461 2021/02 [Refereed][Not invited]
  
• Effectiveness and Limitation of Blockchain in Distributed Optimization: Applications to Energy Management Systems

  Daiki Ogawa, Koichi Kobayashi, Yuh Yamashita

  IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E104-A (2) 423 - 429 0916-8508 2021/02 [Refereed][Not invited]
  
• Sensor Scheduling-Based Detection of False Data Injection Attacks in Power System State Estimation

  Sho Obata, Koichi Kobayashi, Yuh Yamashita

  Digest of Technical Papers - IEEE International Conference on Consumer Electronics 2021- 0747-668X 2021/01/10 

  In state estimation of steady-state power networks, a cyber attack that cannot be detected from the residual (i.e., the estimation error) is called a false data injection attack. In this paper, to enforce security of power networks, we propose a method of detecting a false data injection attack. In the proposed method, a false data injection attack is detected by randomly choosing sensors used in state estimation. The effectiveness of the proposed method is presented by two numerical examples including the IEEE 14-bus system.
• Distributed estimation based on weighted data aggregation over delayed sensor networks

  Ryosuke Adachi, Yuh Yamashita, Koichi Kobayashi

  IFAC Journal of Systems and Control 14 100109 - 100109 2468-6018 2020/12 [Refereed][Not invited]
  
• Design of global smooth implicit control Lyapunov function for multiple-integrator system with input constraint

  Yuh Yamashita, Naoto Adachi, Ryo Nonaka, Koichi Kobayashi

  Systems & Control Letters 145 104776 - 104776 0167-6911 2020/11 [Refereed][Not invited]
  
• Blockchain-Based Optimization of Energy Management Systems with Demand Response

  Daiki Ogawa, Koichi Kobayashi, Yuh Yamashita

  Proc. of the IEEE 9th Global Conference on Consumer Electronics 58 - 59 0916-8508 2020/10 [Refereed][Not invited]
  
• Stochastic Model Predictive Control of Energy Management Systems with Human in the Loop

  Shogo Shimamoto, Koichi Kobayashi, Yuh Yamashita

  Proc. of the IEEE 9th Global Conference on Consumer Electronics 60 - 61 2020/10 [Refereed][Not invited]
  
• Active Vibration Control of Nonlinear 2DOF Mechanical Systems via IDA-PBC

  Sheng Hao, Yuh Yamashita, Koichi Kobayashi

  IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E103.A (9) 1078 - 1085 0916-8508 2020/09/01 [Refereed][Not invited]
  
• On Attack Detection in Sensor Networks Using Distributed Moving Horizon Estimation

  Kei Isono, Koichi Kobayashi, Yuh Yamashita

  Proc. of the SICE Annual Conference 2020 1602 - 1605 2020/09 [Refereed][Not invited]
  
• LMI-Based Simultaneous Design of Controllers and Decentralized Event-Triggering Conditions

  Koichi Kobayashi, Kyohei Nakajima, Yuh Yamashita

  Proc. of the SICE Annual Conference 2020 1585 - 1588 2020/09 [Refereed][Not invited]
  
• Enforcing Security of Power System State Estimation Using Random Sensor Scheduling

  Sho Obata, Koichi Kobayashi, Yuh Yamashita

  Proc. of the SICE Annual Conference 2020 1163 - 1165 2020/09 [Refereed][Not invited]
  
• ADMM-Based Optimization of Distributed Energy Management Systems with Demand Response

  Daiki Ogawa, Koichi Kobayashi, Yuh Yamashita

  Proc. of the 21st IFAC World Congress 2020/07 [Refereed][Not invited]
  
• On Sensor Attack Detection in Control Systems Using Moving Horizon Estimation and Control Performance

  Kei Isono, Koichi Kobayashi, Ryosuke Adachi, Yuh Yamashita

  Proc. of the 21st IFAC World Congress 2020/07 [Refereed][Not invited]
  
• On Minimum Time Control for Dynamical Transportation Using ADMM

  Ryosuke Adachi, Yuh Yamashita, Koichi Kobayashi

  Proc. of the 21st IFAC World Congress 2020/07 [Refereed][Not invited]
  
• Optimal Regulators for Nonlinear Systems with Incompatible State and Input Cost Functions

  Yuh Yamashita, Yuta Sakai, Koichi Kobayashi

  IFAC-PapersOnLine (Special issue of 21st IFAC World Congress) 53 (2) 6819 - 6824 2405-8963 2020/07 [Refereed]
  
• Passivity-Based Nonlinear Active Suspension Control Utilizing Relative Information

  Sheng Hao, Yuh Yamashita, Koichi Kobayashi

  IFAC-PapersOnLine (Special issue of 21st IFAC World Congress) 53 (2) 5586 - 5591 2405-8963 2020/07 [Refereed]
  
• Design of Controller and Observer for Dynamical Network Systems Based on Weighted Degrees

  Ryosuke Adachi, Yuh Yamashita, Koichi Kobayashi

  IFAC-PapersOnLine (Special issue of 21st IFAC World Congress) 53 (2) 3330 - 3335 2405-8963 2020/07 [Refereed]
  
• Model Reduction of Boolean Networks Using BDD

  Fuma Motoyama, Koichi Kobayashi, Yuh Yamashita

  Proc. of the 35th International Technical Conference on Circuits/Systems, Computers and Communications 89 - 93 2020/07 [Refereed][Not invited]
  
• Model Predictive Control of Energy Management Systems with Human Decision Making

  Shogo Shimamoto, Koichi Kobayashi, Yuh Yamashita

  Proc. of the 35th International Technical Conference on Circuits/Systems, Computers and Communications 84 - 88 2020/07 [Refereed][Not invited]
  
• Distributed Observer over Delayed Sensor Networks for Systems with Unknown Inputs

  ADACHI Ryosuke, YAMASHITA Yuh, KOBAYASHI Koichi

  IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences 一般社団法人 電子情報通信学会 E103-A (2) 469 - 477 0916-8508 2020/02 [Refereed][Not invited]
   

  In this paper, we consider the design problem of an unknown-input observer for distributed network systems under the existence of communication delays. In the proposed method, each node estimates all states and calculates inputs from its own estimate. It is assumed that the controller of each node is given by an observer-based controller. When calculating each node, the input values of the other nodes cannot be utilized. Therefore, each node calculates alternative inputs instead of the unknown inputs of the other nodes. The alternative inputs are generated by own estimate based on the feedback controller of the other nodes given by the assumption. Each node utilizes these values instead of the unknown inputs when calculating the estimation and delay compensation. The stability of the estimation error of the proposed observer is proven by a Lyapunov-Krasovskii functional. The stability condition is given by a linear matrix inequality (LMI). Finally, the result of a numerical simulation is shown to verify the effectiveness of the proposed method.

• Dynamic Surveillance by Multiple Agents with Fuel Constraints

  Ryo Masuda, Koichi Kobayashi, Yuh Yamashita

  IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E103-A (2) 462 - 468 2020/02 [Refereed][Not invited]
  
• Self-Triggered Pinning Consensus Control for Multi-Agent Systems

  Shun Andoh, Koichi Kobayashi, Yuh Yamashita

  IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E103.A (2) 443 - 450 0916-8508 2020/02/01 [Refereed][Not invited]
  
• Hierarchical Pinning Control for Consensus of Multi-Agent Systems and Its Application to Vehicle Platooning

  Shun Andoh, Koichi Kobayashi, Yuh Yamashita

  Proceedings of 2020 IEEE/SICE International Symposium on System Integration 1064 - 1069 2020/01 [Refereed][Not invited]
  
• Robust Active Vibration Controller Design for a Class of Underactuated Nonlinear Systems

  Sheng Hao, Yuh Yamashita, Koichi Kobayashi

  Proceedings of 2020 IEEE/SICE International Symposium on System Integration 465 - 470 2020/01 [Refereed][Not invited]
  
• Construction Method of Probabilistic Boolean Networks Based on Imperfect Information

  Katsuaki Umiji, Koichi Kobayashi, Yuh Yamashita

  Algorithms 12 (12) 268 (9 pages)  2019/12 [Refereed][Not invited]
  
• Dynamic Surveillance by Multiple Agents with Fuel Constraints

  Yuh YamashitaRyo Masuda, Koichi Kobayashi, Yuh Yamashita

  Proc. of the 2019 IEEE International Conference on Systems, Man, and Cybernetics 3351 - 3356 2019/10 [Refereed][Not invited]
  
• Stabilization of Nonlinear Systems by Sparse Input with Input Grouping

  Kiminori Sakano, Yuh Yamashita, Koichi Kobayashi

  Proceedings of SICE Annual Conference 2019 1653 - 1656 2019/09 [Refereed][Not invited]
  
• Observer-Based Self-Triggered Pinning Control for Consensus of Multi-Agent Systems

  Yuh YamashitaShun Andoh, Koichi Kobayashi, Yuh Yamashita

  Proceedings of SICE Annual Conference 2019 1440 - 1443 2019/09 [Refereed][Not invited]
  
• On the Optimality of Distributed Observer Using Belief Propagation

  Ryosuke Adachi, Yuh Yamashita, Koichi Kobayashi

  Proceedings of SICE Annual Conference 2019 645 - 648 2019/09 [Refereed][Not invited]
  
• Control of Bilateral Teleoperation System Consisting of Heterogeneous Manipulators with Communication Delay

  Akihisa Higashino, Yuh Yamashita, Koichi Kobayashi

  IFAC PapersOnline (Part of special issue: 11th IFAC Symposium on Nonlinear Control Systems) 52 (16) 747 - 752 2019/09 [Refereed][Not invited]
  
• Design and Value Evaluation of Demand Response Based on Model Predictive Control

  Kodai Miyazaki, Koichi Kobayashi, Shun-Ichi Azuma, Nobuyuki Yamaguchi, Yuh Yamashita

  IEEE Transactions on Industrial Informatics 15 (8) 4809 - 4818 2019/08 [Refereed][Not invited]
  
• Decentralized Event-Triggered Control of Discrete-Time Linear Systems Based on Uniformly Ultimate Boundedness

  Koichi Kobayashi, Kyohei Nakajima, Yuh Yamashita

  Proceedings of the 2019 Asian Control Conference 1392 - 1397 2019/06 [Refereed][Not invited]
  
• Distributed Estimation Over Delayed Sensor Networks with Cyclic Structure

  Ryosuke Adachi, Yuh Yamashita, Koichi Kobayashi

  Proceedings of the 2019 Asian Control Conference 1386 - 1391 2019/06 [Refereed][Not invited]
  
• Attack Detection in Control Systems Based on Unknown Input Observers and Control Performance

  Kei Isono, Koichi Kobayashi, Ryosuke Adachi, Yuh Yamashita

  Proc. of the 34th International Technical Conference on Circuits/Systems, Computers and Communications 290 - 293 2019/06 [Refereed][Not invited]
  
• Effectiveness and Limitation of Blockchain in Distributed Optimization

  Daiki Ogawa, Koichi Kobayashi, Yuh Yamashita

  Proc. of the 34th International Technical Conference on Circuits/Systems, Computers and Communications 286 - 289 2019/06 [Refereed][Not invited]
  
• Blockchain-Based Distributed Optimization for Energy Management Systems

  Daiki Ogawa, Koichi Kobayashi, Yuh Yamashita

  Proceedings of 2019 IEEE International Conference on Industrial Cyber Physical Systems 706 - 711 2019/05 [Refereed][Not invited]
  
• Distributed Estimation over Delayed Sensor Network with Scalable Communication

  Ryosuke Adachi, Yuh Yamashita, Koichi Kobayashi

  IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E102-A (5) 712 - 720 2019/05 [Refereed][Not invited]
  
• Computationally Efficient Model Predictive Control for Multi-Agent Surveillance Systems

  Koichi Kobayashi, Mifuyu Kido, Yuh Yamashita

  IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences E102-A (2) 372 - 378 2019/02 [Refereed][Not invited]
  
• Convergence Rates of Stochastic Homogeneous Systems

  Kenta Hoshino, Yuki Nishimura, Yuh Yamashita

  Systems & Control Letters 124 33 - 39 2019/02 [Refereed][Not invited]
  
• Asymptotic stabilization of nonholonomic four-wheeled vehicle with steering limitation

  Wataru Hashimoto, Yuh Yamashita, Koichi Kobayashi

  IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences E102-A (1) 227 - 234 2019/01 [Refereed][Not invited]
  
• Active Nonlinear Tuned Mass Damper via IDA-PBC

  Sheng Hao, Yuh Yamashita, Koichi Kobayashi

  Proc. of 2018 IEEE International Conference on Systems, Man, and Cybernetics 4383 - 4388 2018/10 [Refereed][Not invited]
  
• Computationally Efficient Model Predictive Control for Multi-Agent Surveillance Systems

  Koichi Kobayashi, Mifuyu Kido, Yuh Yamashita

  Proc. of 2018 IEEE International Conference on Systems, Man, and Cybernetics 2015 - 2020 2018/10 [Refereed][Not invited]
  
• Observer Design for Distributed Network Systems with Communication Delays

  Ryosuke Adachi, Yuh Yamashita, Koichi Kobayashi

  IFAC PapersOnline; Proceedings of the 5th IFAC Conference on Analysis and Control of Chaotic Systems 51 (33) 115 - 125 2018/10 [Refereed][Not invited]
  
• Switching Controller Design for Quantized Event-Triggered Control

  Shumpei Yoshikawa, Koichi Kobayashi, Yuh Yamashita

  Proceedings of the SICE Annual Conference 2018 1797 - 1800 2018/09 [Refereed][Not invited]
  
• Self-Triggered Predictive Pinning Control for Consensus of Multi-Agent Systems

  Shun Andoh, Koichi Kobayashi, Yuh Yamashita

  Proceedings of the SICE Annual Conference 2018 1806 - 1809 2018/09 [Refereed][Not invited]
  
• Asymptotically Stabilizing Controller Generating Sparse Input for Nonlinear Systems

  Yuh Yamashita, Kiminori Sakano, Koichi Kobayashi

  Proc. of the 23rd International Symposium on Mathematical Theory of Networks and Systems 435 - 440 2018/07 [Refereed][Not invited]
  
• MPC-Based Design of Demand Response Programs in Energy Management Systems

  Kodai Miyazaki, Koichi Kobayashi, Shun-ichi Azuma, Nobuyuki Yamaguchi, Yuh Yamashita

  Proc. of the 33rd International Technical Conference on Circuits/Systems, Computers and Communications 2018/07 [Refereed][Not invited]
  
• Vibration Suppression of Hamiltonian Systems with Velocity and Force Disturbances Using IDA-PBC

  Sheng Hao, Yuh Yamashita, Koichi Kobayashi

  IFAC Papers Online, Proc. of the Second IFAC Conference on Modelling, Identification and Control of Nonlinear Systems 51 (13) 285 - 290 2018/06 [Refereed][Not invited]
  
• MPC-based Co-design of Control and Routing for Wireless Sensor and Actuator Networks

  Dai Satoh, Koichi Kobayashi, Yuh Yamashita

  International Journal of Control, Automation and Systems 16 (3) 953 - 960 2005-4092 2018/06/01 [Refereed][Not invited]
   

  A wireless sensor and actuator network (WSAN) is a class of networked control systems. In WSANs, sensors and actuators are located in a distributed way, and communicate to controllers through a wireless communication network such as a multi-hop network. In this paper, we propose a model predictive control (MPC) method for co-design of control and routing of WSANs. MPC is an optimal control strategy based on numerical optimization. The control input is calculated by solving the finite-time optimal control problem at each discrete time. In the proposed method, a WSAN is modeled by a switched linear system. In the finite-time optimal control problem, a control input and a mode corresponding to a communication path are optimized simultaneously. The proposed method is demonstrated by a numerical example.
• Optimal Monitoring of Multiple Agents via Time Sequence-Based Modeling

  Ryo MASUDA, Koichi KOBAYASHI, Yuh YAMASHITA

  SICE Journal of Control, Measurement, and System Integration 11 (3) 169 - 173 2018/05 [Refereed][Not invited]
  
• Delay-compensated maximum-likelihood-estimation method and its application for quadrotor UAVs

  Ryosuke Adachi, Yuh Yamashita

  IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E101A (4) 678 - 684 1745-1337 2018/04/01 [Refereed][Not invited]
   

  This study proposes a maximum-likelihood-estimation method for a quadrotor UAV given the existence of sensor delays. The state equation of the UAV is nonlinear, and thus, we propose an approximated method that consists of two steps. The first step estimates the past state based on the delayed output through an extended Kalman filter. The second step involves calculating an estimate of the present state by simulating the original system from the past to the present. It is proven that the proposed method provides an approximated maximum-likelihood-estimation. The effectiveness of the estimator is verified by performing experiments.
• Nonlinear system identification by affine coordinate unification of locally identified MIMO linear systems

  Kazuya Nomura, Yuh Yamashita, Koichi Kobayashi

  Proc. of the SICE International Symposium on Control Systems 2018 220 - 225 2018/03 [Refereed][Not invited]
  
• Quantized event-triggered control of discrete-time linear systems with switching triggering conditions

  Shumpei Yoshikawa, Koichi Kobayashi, Yuh Yamashita

  IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E101A (2) 322 - 327 1745-1337 2018/02/01 [Refereed][Not invited]
   

  Event-triggered control is a method that the control input is updated only when a certain triggering condition is satisfied. In networked control systems, quantization errors via A/D conversion should be considered. In this paper, a new method for quantized event-triggered control with switching triggering conditions is proposed. For a discrete-time linear system, we consider the problem of finding a state-feedback controller such that the closed-loop system is uniformly ultimately bounded in a certain ellipsoid. This problem is reduced to an LMI (Linear Matrix Inequality) optimization problem. The volume of the ellipsoid may be adjusted. The effectiveness of the proposed method is presented by a numerical example.
• Markov Chain-Based Modeling Techniques of Appliances for Demand Response

  Kenta Ohashi, Koichi Kobayashi, Yuh Yamashita

  Proc. of the 23rd International Symposium on Artificial Life and Robotics 805 - 808 2018/01 [Refereed][Not invited]
  
• Model Predictive-Based Demand Response in Energy Management Systems

  Yuh YamashitaKodai Miyazaki, Koichi Kobayashi, Shun-ichi Azuma, Nobuyuki Yamaguchi, Yuh Yamashita

  Proc. of the 23rd International Symposium on Artificial Life and Robotics 815 - 818 2018/01 [Refereed][Not invited]
  
• BMI approach to design of networked control systems with decentralized event-triggering

  Kyohei Nakajima, Koichi Kobayashi, Yuh Yamashita

  IEEE Workshop on Signal Processing Advances in Wireless Communications, SPAWC 2017- 1 - 5 2017/12/19 [Refereed][Not invited]
   

  In a networked control system (NCS) where plants and controllers are connected through communication networks, it is important to decrease the number of times of communications under preserving of control performances such as optimality and stability. From this viewpoint, event-triggered control has been studied so far. In event-triggered control, the measured signal is sent to the controller only when a triggering condition is satisfied. In this paper, the control problem with decentralized event-triggering conditions is investigated. Here, generalized event-triggering conditions with design parameters are utilized. First, the control problem studied here is formulated. Next, this original problem is reduced to the problem of minimizing an upper bound of the cost function in the original problem. Furthermore, the reduced problem is approximated by a BMI (bilinear matrix inequality) optimization problem. Finally, the proposed method is demonstrated by a numerical example.
• Asymptotic Stabilization of Nonholonomic Four-Wheeled Vehicle with Hysteresis Mechanism

  Wataru Hashimoto, Yuh Yamashita, Koichi Kobayashi

  Proceedings of the 2017 International Symposium on Nonlinear Theory and Its Applications 30 - 33 2017/12 [Refereed][Not invited]
  
• A unification method of locally identified linear systems and reconstruction of nonlinear dynamical model

  Kazuya Nomura, Yuh Yamashita, Koichi Kobayashi

  IFAC-PapersOnLine 50 (1) 14004 - 14009 2405-8963 2017/07/01 [Refereed][Not invited]
   

  In this study, we propose an identification method of a state-space model for discrete-time SISO nonlinear systems. The first step of the procedure is to construct models which approximate local dynamics around stationary points of the system using a subspace method. The second step is to describe the local models in one unified coordinate using affine coordinate transformations. The coordinate transformations are determined based on the similarity of adjacent local models by the least-squares method. The model describes quasi-steady behavior of the plant. Simulation results of the proposed method are presented.
• Data Aggregation based Estimation for Sensor Network with Communication Delay

  Ryosuke Adachi, Yuh Yamashita, Koichi Kobayashi

  IFAC-PapersOnLine 50 (1) 2488 - 2493 2405-8963 2017/07/01 [Refereed][Not invited]
   

  In this paper, a distributed delay-compensated observer for wireless sensor networks is proposed. Each node of the sensor network aggregates data from the other nodes and sends the aggregated data to the neighbor nodes. All nodes estimate the state variables of a system simultaneously. The observer in each node is similar to the delay-compensated observer with multi-sensor delays proposed by Watanabe. The effectiveness of the proposed method is verified by numerical simulation.
• Asymptotic Stabilization of Nonlinear Systems with Convex-Polytope Input Constraints and its Inverse Optimality

  Yuh Yamashita, Ryosuke Matsukizono, Koichi Kobayashi

  IFAC-PapersOnLine 50 (1) 1397 - 1402 2405-8963 2017/07/01 [Refereed][Not invited]
   

  In this study, we propose an asymptotic stabilization controller for a nonlinear system with a convex-polytope input constraint. Moreover, we establish a condition that the controller has inverse optimality in the neighborhood of the origin. The controller input is continuous in the set where the asymptotic stabilization is guaranteed. We consider the asymmetric constraint for zero-input, and this bias is adjusted by using an un-uniform scaling on each vertex point, in the neighborhood of the origin. Therefore, the input cost in the inverse optimal performance functional is approximated by a quadratic form near the origin.
• Switched Probabilistic Model of Consumers for Demand Response

  Kenta Ohashi, Koichi Kobayashi, Yuh Yamashita

  Proceedings of the 32nd International Technical Conference on Circuits, Systems, Computers, and Communications 143 - 146 2017/07 [Refereed][Not invited]
  
• Approximate MLD System Model of Switched Linear Systems for Model Predictive Control

  Shin Kanazawa, Koichi Kobayashi, Yuh Yamashita

  SICE Journal of Control, Measurement, and System Integration 10 (3) 136 - 140 2017/05 [Refereed][Not invited]
  
• MPC-Based Surveillance over Graphs by Multiple Agents

  Mifuyu Kido, Koichi Kobayashi, Yuh Yamashita

  SICE Journal of Control, Measurement, and System Integration 10 (3) 253 - 258 2017/05 [Refereed][Not invited]
  
• Linear Quadratic Regulator with Decentralized Event-Triggering

  Kyohei Nakajima, Koichi Kobayashi, Yuh Yamashita

  IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES E100A (2) 414 - 420 1745-1337 2017/02 [Refereed][Not invited]
   

  Event-triggered control is a control method that the measured signal is sent to the controller only when a certain triggering condition on the measured signal is satisfied. In this paper, we propose a linear quadratic regulator (LQR) with decentralized triggering conditions. First, a suboptimal solution to the design problem of LQRs with decentralized triggering conditions is derived. A state-feedback gain can be obtained by solving a convex optimization problem with LMI (linear matrix inequality) constraints. Next, the relation between centralized and decentralized triggering conditions is discussed. It is shown that control performance of an LQR with decentralized event-triggering is better than that with centralized event-triggering. Finally, a numerical example is illustrated.
• Periodic Model Predictive Control of Multi-Hop Control Networks

  Dai Satoh, Koichi Kobayashi, Yuh Yamashita

  IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES E100A (2) 406 - 413 1745-1337 2017/02 [Refereed][Not invited]
   

  In this paper, a new method of model predictive control (MPC) for a multi-hop control network (MHCN) is proposed. An MHCN is a control system in which plants and controllers are connected through a multi-hop wireless network. In the proposed method, (i) control inputs and (ii) paths used in transmission of control inputs are computed with constant period by solving the finite-time optimal control problem. First, a mathematical model for expressing an MHCN is proposed. This model is given by a switched linear system, and is compatible with MPC. Next, the finite-time optimal control problem using this model is formulated, and is reduced to a mixed integer quadratic programming problem. Finally, a numerical example is presented to show the effectiveness of the proposed method.
• Quantized Event-Triggered Control of Discrete-Time Linear Systems with Switching Triggering Conditions

  Shumpei Yoshikawa, Koichi Kobayashi, Yuh Yamashita

  2017 56TH ANNUAL CONFERENCE OF THE SOCIETY OF INSTRUMENT AND CONTROL ENGINEERS OF JAPAN (SICE) 313 - 316 2017 [Refereed][Not invited]
   

  Event-triggered control is a method that the control input is updated only when a certain triggering condition is satisfied. In networked control systems, quantization errors via A/D conversion should be considered. In this paper, a new method for quantized event-triggered control with switching triggering conditions is proposed. For a discrete-time linear system, we consider the problem of finding a state-feedback controller such that the closed-loop system is uniformly ultimately bounded in a certain ellipsoid. This problem is reduced to an LMI (Linear Matrix Inequality) optimization problem. The volume of the ellipsoid can be adjusted.
• Optimal Monitoring of Multiple Agents via Time Sequence-Based Modeling

  Ryo Masuda, Koichi Kobayashi, Yuh Yamashita

  2017 56TH ANNUAL CONFERENCE OF THE SOCIETY OF INSTRUMENT AND CONTROL ENGINEERS OF JAPAN (SICE) 168 - 171 2017 [Refereed][Not invited]
   

  The multi-agent monitoring (surveillance) problem over graphs is to find trajectories of multiple agents that travel each node as evenly as possible. This problem has several applications such as city safety management and disaster rescue. In our previously proposed method, the finite-time optimal surveillance problem was formulated, and was reduced to a mixed integer linear programming (MILP) problem. Based on the policy of model predictive control, an optimal trajectory is generated by solving the MILP problem at each discrete time. However, the computation time for solving the MILP problem is frequently long. In this paper, to reduce the computation time of the MILP problem, a modeling method of graphs is proposed. In this method, the adjacency relation is time varying depending on the current position of agents. Since redundant arcs are eliminated, the computation time is improved. The effectiveness of the proposed method is demonstrated by numerical simulations.
• Stochastic Model Predictive Control of Multi-Hop Control Networks with Packet Dropouts

  Dai Satoh, Koichi Kobayashi, Yuh Yamashita

  2017 56TH ANNUAL CONFERENCE OF THE SOCIETY OF INSTRUMENT AND CONTROL ENGINEERS OF JAPAN (SICE) 164 - 167 2017 [Refereed][Not invited]
   

  A multi-hop control network (MHCN) is a control system in which plants and controllers are connected through a multi-hop wireless network. An MHCN is one of the typical examples in cyber-physical systems. In this paper, we propose a new method of stochastic model predictive control for MHCNs with packet dropouts. In the proposed method, a given MHCN is modeled by a stochastic switched system. Then, we consider the finite-time optimal control problem of minimizing the cost function given by the quadratic form with respect to the expected value of the state and the control input. This problem is reduced to a mixed integer programming problem. By solving it, both communication paths and control inputs are optimized simultaneously.
• Potential Game on Measures and its Dynamical Behavior

  Yuh Yamashita

  2017 56TH ANNUAL CONFERENCE OF THE SOCIETY OF INSTRUMENT AND CONTROL ENGINEERS OF JAPAN (SICE) 209 - 213 2017 [Refereed][Not invited]
   

  This work presents a framework of dynamical systems consists of infinite-number of spatially distributed units. The units are classified into several kinds of units, and each unit has relationships with other kinds of units, e.g. communication, commuting, trades, lease, etc. Such a system can be represented by some Radon measures with some constraints. The units move their position, as well as associated relationships, according to the unit profits. The Nash equilibrium can be represented as a potential with constraints. The dynamical system can be obtained as a gradient-like system for the potential.
• Periodic Model Predictive Control of Multi-Hop Control Networks

  Dai Satoh, Koichi Kobayashi, Yuh Yamashita

  Proceedings of the 2016 IEEE International Conference on Systems, Man, and Cybernetics 2016/10 [Refereed][Not invited]
  
• Backstepping for Set-valued Upper Control Laws and Its Application to Control Allocation Problem

  Daiki Suzuki, Yuh Yamashita, Koichi Kobayashi

  Proceedings of the 2016 IEEE International Conference on Systems, Man, and Cybernetics 一般社団法人 システム制御情報学会 29 (4) 175 - 181 1342-5668 2016/10 [Refereed][Not invited]
   

  This paper provides a new framework of control allocation of over-actuated system for static optimization of inputs via dynamical extension and potential approach. The static optimization of the control allocation is performed in real-time approximately, by varying the input according to the potential. To ensure asymptotic stability of the controlled system, we extends the backstepping method to our cases where more flexible additional potential can be used. Under the conditions on the set of the minimizer, the growth rate around the set, and the unimodality of the additional potential with some auxiliary assumptions, the extended potential function becomes a control Lyapunov function of the augmented system. The effectiveness of the proposed method is demonstrated by simulations.
• Approximate MLD System Model of Switched Linear Systems for Model Predictive Control

  Shin Kanazawa, Koichi Kobayashi, Yuh Yamashita

  Proceedings of the SICE Annual Conference 2016 1745 - 1748 2016/09 [Refereed][Not invited]
  
• Model Predictive Control of Multiple Plants over Communication Networks

  Dai Satoh, Koichi Kobayashi, Yuh Yamashita

  Proceedings of the SICE Annual Conference 2016 1737 - 1740 2016/09 [Refereed][Not invited]
  
• Global Asymptotic Stabilization of Nonlinear Deterministic Systems Using Wiener Processes

  Kenta Hoshino, Yuki Nishimura, Yuh Yamashita, Daisuke Tsubakino

  IEEE TRANSACTIONS ON AUTOMATIC CONTROL 61 (8) 2318 - 2323 0018-9286 2016/08 [Refereed][Not invited]
   

  The objective of this study is to present a noise-assisted stabilization method and a constructive method for designing a stabilizing controller. We investigate the stabilization of a deterministic nonlinear affine system by using a controller with a Wiener process. Our approach focuses on the global asymptotic stabilization of nonholonomic systems. The proposed method for designing a stabilizing controller is based on the notion of a stochastic control Lyapunov function. We show that if there exists a stochastic control Lyapunov function with small control property, the designed controller globally asymptotically stabilizes a given system with probability one.
• An MILP Approach to Optimal Surveillance over Graphs

  Mifuyu Kido, Koichi Kobayashi, Yuh Yamashita

  Proc. of the 31st International Technical Conference on Circuits/Systems, Computers and Communications 133 - 136 2016/07/11 [Refereed][Not invited]
  
• Backstepping for set-valued upper control laws and its application to control allocation problem

  Daiki Suzuki, Yuh Yamashita

  Transactions of the Institute of Systems, Control and Information Engineers 一般社団法人 システム制御情報学会 29 (4) 175 - 181 1342-5668 2016/04 [Refereed][Not invited]
   

  This paper provides a new framework of control allocation of over-actuated system for static optimization of inputs via dynamical extension and potential approach. The static optimization of the control allocation is performed in real-time approximately, by varying the input according to the potential. To ensure asymptotic stability of the controlled system, we extends the backstepping method to our cases where more flexible additional potential can be used. Under the conditions on the set of the minimizer, the growth rate around the set, and the unimodality of the additional potential with some auxiliary assumptions, the extended potential function becomes a control Lyapunov function of the augmented system. The effectiveness of the proposed method is demonstrated by simulations.
• Linear Quadratic Regulator with Decentralized Event-Triggering

  Kyohei Nakajima, Koichi Kobayashi, Yuh Yamashita

  PROCEEDINGS OF THE IECON 2016 - 42ND ANNUAL CONFERENCE OF THE IEEE INDUSTRIAL ELECTRONICS SOCIETY 5374 - 5379 1553-572X 2016 [Refereed][Not invited]
   

  Event-triggered control is a control method that the measured signal is sent to the controller only when a certain condition on the measured signal is satisfied. In this paper, we propose a decentralized event-triggered linear quadratic regulator (LQR). First, a suboptimal solution to the decentralized event-triggered LQR problem is derived. A state-feedback gain can he obtained by solving an LMI (linear matrix inequality) optimization problem. Next, the relation between centralized and decentralized event-triggered LQR problems is discussed. It is shown that control performance of a decentralized event triggered LQR is better than that of a centralized event-triggered LQR. Finally, a numerical example is illustrated.
• Asymptotic Stabilization of Nonholonomic Four-Wheeled Vehicle with Steering Limitation based on Lyapunov Function Approach

  W. Hashimoto, Y. Yamashita, R. Nonaka, K. Kobayashi

  IFAC PAPERSONLINE 49 (18) 235 - 240 2405-8963 2016 [Refereed][Not invited]
   

  In this paper, we propose a new control law for the asymptotic stabilization of a four-wheeled vehicle with a steering angle limitation. The control law is based on a locally semiconcave control Lyapunov function (LS-CLF) for the chained system proposed by Kimura et al. (2015) that is converted by coordinate and input transformations without singular points. We confirm that the LS-CLF is also effective for the four-wheeled vehicle case, i.e., such inputs exist in the input constraint that decrease the LS-CLF. We also design a control law by using the LS-CLF and steering angle constraint that achieves asymptotic stabilization of the origin of a four-wheeled system while avoiding pivot turns. We confirm the effectiveness of the proposed control law via a computer simulation and an experiment. (C) 2016, IFAC (International Federation of Automatic Control)Hosting by Elsevier Ltd. All rights reserved.
• Multiple obstacle avoidance of four-wheeled vehicle with steering limitation using nondifferentiable control Lyapunov function

  Ryo Nonaka, Yuh Yamashita, Daisuke Tsubakino

  ADVANCED ROBOTICS 30 (1) 15 - 28 0169-1864 2016/01 [Refereed][Not invited]
   

  Controlling a mobile robot in a space with obstacles is a well-known problem in robotics. The control objective is for the mobile robot to reach a goal point with obstacle avoidance. In this paper, we specially consider the multiple obstacle avoidance problem for particularly a four-wheeled vehicle. Assuming that the shapes and locations of the obstacles are known, we propose a design method of a nondifferentiable navigation function, which guides a vehicle at the desired point. The control law for the four-wheeled vehicle is obtained from the extended function of the navigation function. As four-wheeled vehicles cannot move sideways because of their nonholonomic constraint, the proposed control law addresses this difficulty by considering a decrease in the control Lyapunov function, and can be applied to vehicles with steering limitations. Moreover, the control law makes it possible for the vehicles to achieve an n-point turn automatically without the need for any rule-based decision-making or heuristic method. The four-wheeled vehicle can reach the goal point from any initial point under the proposed control law. Our experimental results with a small four-wheeled vehicle are presented at the end of this paper.
• Vibration suppression for mass-spring-damper systems with a tuned mass damper using interconnection and damping assignment passivity-based control

  Takashi Aoki, Yuh Yamashita, Daisuke Tsubakino

  INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL 26 (2) 235 - 251 1049-8923 2016/01 [Refereed][Not invited]
   

  This paper considers a vibration suppression control method using feedback for a mass-spring-damper system with a tuned mass damper. For vibration suppression, we adopt the interconnection and damping assignment passivity-based control, whereby the system is transformed to a system with a skyhook damper with an artificial structure matrix. The feedback law includes no accelerometer signal and uses only information on relative displacements and velocities. The proposed control method can simultaneously suppress the influences of the floor vibration and the disturbance force acting on the main body. A guideline for choosing parameters of the desired system is shown. The proposed method can be easily extended to nonlinear cases, which is demonstrated for a nonlinear-spring case. We also show the input-to-state stability property of closed-loop systems for linear cases and nonlinear cases. Copyright (C) 2015 John Wiley & Sons, Ltd.
• Continuous-time delayed feedback control for chaotic systems using complex number observer

  Yuh Yamashita

  IFAC-PapersOnLine 28 (18) 199 - 204 2405-8963 2015/11/01 [Refereed][Not invited]
   

  This paper propose a new delayed feedback control (DFC) method which is an extension of the observer-based DFC method to continuous-time cases for the stabilization problem of an unstable periodic orbit (UPO). The proposed method construct a complex-number observer which estimates the tracking error against the UPO. This paper proposes the extension of the author's previous research, and can be used for the time-invariant chaotic systems. The controller tunes the time-shift value of the desired UPO, and overcomes the problem of pole-zero canceling at the origin in the complex plane. The proposed method is applied to the stabilization problem of a UPO in the trajectories of Lorenz model.
• Maximum Likelihood Estimation Method for Nonlinear System with Sensor Delay

  Ryosuke Adachi, Yuh Yamashita, Daisuke Tsubakino

  Proceedings of SICE Annual Conference 2015 626 - 629 2015/07 [Not refereed][Not invited]
  
• Static State Feedback Control System Design for PVTOL System via Minimum Projection Method

  KUGA SOKI, SATO YASUYUKI, NAKAMURA HISAKAZU, YAMASHITA YU

  Transactions of the Society of Instrument and Control Engineers The Society of Instrument and Control Engineers 51 (5) 361 - 370 0453-4654 2015/05 [Refereed][Not invited]
   

  "Dynamic extension" is commonly used for stabilization of planar vertical takeoff and landing (PVTOL) system. Most of controllers designed by this method suffer from singularities of division-by-zero. We propose a "static" control Lyapunov function (CLF) design method for a PVTOL system by using a CLF obtained by dynamic extension and minimum projection method. Then, we design an inverse optimal controller with the designed static CLF. Moreover, we show that the proposed controller successfully stabilizes a desired operating point even in the neighborhood of the singularity where the conventional dynamic extension can not stabilize.
• Asymptotic Stabilization of Two-Wheeled Mobile Robot via Locally Semiconcave Generalized Homogeneous Control Lyapunov Function

  Shunsuke KIMURA, Hisakazu NAKAMURA, Yuh YAMASHITA

  SICE Journal of Control, Measurement, and System Integration The Society of Instrument and Control Engineers 8 (2) 122 - 130 1882-4889 2015/03 [Refereed][Not invited]
   

  A locally semiconcave control Lyapunov function exists for every globally asymptotically controllable system; however for nonholonomic systems, the issue of a locally semiconcave generalized homogeneous control Lyapunov function is not investigated. In this paper, the authors propose a locally semiconcave generalized homogeneous control Lyapunov function for Brockett integrator as a canonical form of nonholonomic systems. Moreover, the authors propose an exponentially stabilizing controller for a two-wheeled mobile robot with the function. The effectiveness of the proposed method are confirmed by computer simulation and an experiment, and advantages over previously proposed controllers are confirmed by experiments.
• Stabilization of Artstein's Circle by Continuous Stochastic Feedback

  Kenta Hoshino, Yuki Nishimura, Yuh Yamashita, Jun Yoneyama

  2015 IEEE CONFERENCE ON CONTROL AND APPLICATIONS (CCA 2015) 257 - 262 1085-1992 2015 [Refereed][Not invited]
   

  This paper presents the asymptotic stabilization of the Artstein's circle using stochastic processes in a control law. To construct a C-2 control Lyapunov function (CLF) for a stabilization method using stochastic processes, we synthesize a nonsmooth CLF for a nonsmooth stabilization method and a smooth function. By synthesizing these functions, we obtain a C-2 CLF. By this C-2 CLF, we can obtain a continuous stabilizing feedback using stochastic processes for the Artstein's circle.
• Delay-Compensated Maximum Likelihood Estimation Method for Quadrotor UAV

  Ryosuke Adachi, Yuh Yamashita

  2015 IEEE CONFERENCE ON CONTROL AND APPLICATIONS (CCA 2015) 601 - 606 1085-1992 2015 [Refereed][Not invited]
   

  This paper considers a maximum likelihood estimation problem for a quadrotor UAV under the existence of sensor delays. Since the state equation of the UAV is nonlinear, we propose an approximated method consisting of the following two steps. The first step is devoted to estimation of the past state based on the delayed output. We use an extended Kalman filter for this purpose. As the second step, an estimate of the present state is calculated by simulating the linear approximated system from the past to the present time. It is proved that the proposed method provides an approximated maximum likelihood estimation. The effectiveness of the estimator is verified by an experiment.
• Higher-Order Sliding-Mode Control for Binary Input by Using Implicit Lyapunov Function

  Ryo Nonaka, Yuh Yamashita, Daisuke Tsubakino

  IFAC-PapersOnLine 48 (11) 866 - 871 2405-8963 2015 [Refereed][Not invited]
   

  We propose a binary input controller for higher-order sliding-mode control. The proposed method extends the continuous controller for higher-order sliding-mode control to applicable for a system with a binary input constraint. Under the binary input constraint, the controller for the system can only use two input such as ±1. We design a binary input controller for the system based on the implicit Lyapunov function method. We also reduce the chattering phenomenon on the sliding hypersurface except on the origin. The reduction mechanism provides strong effect for the chattering reduction under three-valued input constraint ±1 and zero, which is demonstrated in the simulation in this paper.
• State estimation for boundary-coupled parabolic distributed parameter systems using spatial averages

  Daisuke Tsubakino, Yuh Yamashita

  2015 10TH ASIAN CONTROL CONFERENCE (ASCC) 2015 [Refereed][Not invited]
   

  This paper proposes an indirect method for designing a Luenberger-type state observer for systems described by boundary-coupled two parabolic partial differential equations. In particular, we concentrate on the case where outputs are spatial averages of the state variables. The proposed method consists of two steps. We first introduce a state transformation that converts the system into another system with boundary measurement. Then, the backstepping approach can provide a state observer for the converted system. An estimate of the original state variables is constructed through the inverse transformation. The performance of the proposed observer is confirmed by a numerical simulation.
• General Scheme for Design of Higher-Order Sliding-Mode Controller

  Ryo Nonaka, Yuh Yamashita, Daisuke Tsubakino

  2015 AMERICAN CONTROL CONFERENCE (ACC) 5176 - 5181 0743-1619 2015 [Refereed][Not invited]
   

  Higher-order sliding-mode control has exclusive properties, such as robustness against the disturbance and uncertainty. Moreover, the finite-time stability of a system can be realized with a homogeneous sliding-mode controller. However, designing a higher-order sliding-mode controller is difficult. In this paper, we introduce a general strategy that includes various types of homogeneous sliding-mode control laws. We can check the stability of a system under the control law with some explicit inequalities. Therefore, we can theoretically design the controller even if the target system has input constraints, bounded disturbances, and uncertainty.
• Asymptotic stabilization of nonlinear systems on general manifolds via minimum projection method

  Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani

  2009 European Control Conference, ECC 2009 2757 - 2762 2014/03/26 

  Asymptotic stabilization on noncontractible manifolds is known as a difficult control problem. For the problem, we proposed the minimum projection method to design a nonsmooth control Lyapunov function on a manifold. However, how to stabilize the control system defined on the manifold with the obtained control Lyapunov function remains a problem. Then, a Rifford-type formula on general manifolds is proposed with nonsmooth control Lyapunov functions via the minimum projection method in this paper. Moreover, we prove our proposed method asymptotically stabilize the origin of the control system defined on the manifold in the sense of Euler and π-trajectory. The effectiveness of the proposed method is illustrated by an example of collision avoidance of a mobile robot.
• Discrete-Time Approximation under Zero-Order Holder and Its Application to Continuous-Time System Identification

  Aoki Daisuke, Tsubakino Daisuke, Yamashita Yuh

  Proceedings of the Japan Joint Automatic Control Conference 自動制御連合講演会 57 1412 - 1415 2014 

  連続時間伝達関数から離散時間近似伝達関数を得る方法として，Tustin 変換を用いる方法が知られている．これは時間領域では，台形則による数値積分に対応し，入力が連続関数であれば離散時間近似として妥当なものである．しかしながら，現実よく用いられる零次ホールダを経由すると，入力が不連続関数となってしまう．そこで本研究では，入力の不連続性を考慮したさまざまな次数の離散時間近似式を導出する．さらに，離散時間近似式とその変換を用いた，間接的な連続時間システムの同定についても考察する．
• Stability Preserving Model Reduction by Moment Matching for Hierarchical Systems

  Minami Ryoichiro, Tsubakino Daisuke, Yamashita Yuh

  Proceedings of the Japan Joint Automatic Control Conference 自動制御連合講演会 57 814 - 817 2014 

  本稿では，階層構造をもつ線形システムに対して，安定性を考慮したモーメントマッチングによる低次元化法を考察する．モーメントマッチングでは，サブシステム毎に低次元化を行った場合に，システム全体のモーメントマッチングが達成できることが知られている．しかしながら，元のシステムの安定性が必ずしも保存されないという問題がある．そこで本研究では，サブシステムの低次元化モデルのL2ゲインを適切に設定することにより，低次元化システムの安定性を保証することを提案する．
• Homogeneous Stabilization of Driftless Input-Affine Systems Using Wiener Processes

  Kenta Hoshino, Yuh Yamashita, Yuki Nishimura, Daisuke Tsubakino

  2014 IEEE 53RD ANNUAL CONFERENCE ON DECISION AND CONTROL (CDC) 3167 - 3172 0743-1546 2014 [Refereed][Not invited]
   

  This paper presents a method for the homogeneous stabilization of homogeneous driftless input-affine systems using feedback controllers with Wiener processes. Although previous studies have shown methods for the stabilization of nonholonomic systems by using Wiener processes, the closed-loop systems sometimes show slow convergence. To improve the convergence rate, we show a method that gives a homogeneous controller by redesigning the controllers designed by the previous methods. By the virtue of the homogeneity, the closed-loop systems exhibit almost sure exponential stability with respect to homogeneous norms. A numerical example shows the effectiveness of the proposed method.
• Collision-free Formation Control of Two-wheeled Vehicles based on Triangular LQ Optimal Regulator

  Takashi Kusunoki, Daisuke Tsubakino, Yuh Yamashita

  2014 IEEE CONFERENCE ON CONTROL APPLICATIONS (CCA) 1072 - 1077 1085-1992 2014 [Refereed][Not invited]
   

  This paper considers a formation control problem of two-wheeled vehicles. We first design a base controller based on the structured linear quadratic optimal regulator. The resulting optimal control gain is a lower triangular matrix; thus, agents communicate with each other in a top-down manner. However, vehicles may collide with each other under this control law since it is linear. To avoid collision of vehicles, we design a potential function by deforming the quadratic form of the stabilizing solution of the Riccati equation. The gradient of the potential function gives a control law that guarantees collision avoidance. The control law coincides with the optimal control law if vehicles are far from each other. The effectiveness of the proposed controller is confirmed by numerical simulation.
• Boundary control of a cascade of two parabolic PDEs with different diffusion coefficients

  Daisuke Tsubakino, Miroslav Krstic, Yuh Yamashita

  Proc. 52nd IEEE Conf. Dec. & Cont. 3720 - 3725 0743-1546 2013/12 [Refereed][Not invited]
  
• Stochastic Asymptotic Stabilizers for Deterministic Input-Affine Systems Based on Stochastic Control Lyapunov Functions

  Yuki Nishimura, Kanya Tanaka, Yuji Wakasa, Yuh Yamashita

  IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES E96A (8) 1695 - 1702 1745-1337 2013/08 [Refereed][Not invited]
   

  In this paper, a stochastic asymptotic stabilization method is proposed for deterministic input-affine control systems, which are randomized by including Gaussian white noises in control inputs. The sufficient condition is derived for the diffusion coefficients so that there exist stochastic control Lyapunov functions for the systems. To illustrate the usefulness of the sufficient condition, the authors propose the stochastic continuous feedback law, which makes the origin of the Brockett integrator become globally asymptotically stable in probability.
• Boundary Control of Boundary Coupled Parabolic Distributed Parameter Systems based on Partial State Transformation

  Daisuke Tsubakino, Kazuya Nomura, Yuh Yamashita

  Transactions of the Institute of Systems, Control and Information Engineers 一般社団法人 システム制御情報学会 26 (7) 277 - 287 1342-5668 2013/07 [Refereed][Not invited]
   

  This paper considers a boundary stabilization problem of systems described by boundary coupled two one-dimensional parabolic partial differential equations based on the backstepping method. Unlike the conventional backstepping framework, we propose a state transformation that contains the state of the unforced subsystem partially. It is proved that this transformation is well-defined and converts the original system into an exponentially stable system together with an associated state feedback control law under a condition that ensures the stability of the unforced subsystem. The original system with this control law inherits the stability of the transfomed one. The effectiveness of the obtained control law is demonstrated numerically.
• Stochastic Extremum-Seeking Algorithm for One-Dimensional and Multivariate Static Systems

  HOSHINO KENTA, YAMASHITA YUH

  SICE J Control Meas Syst Integr The Society of Instrument and Control Engineers 6 (3) 177 - 185 1882-4889 2013/05 [Refereed][Not invited]
   

  The aim of this paper is to present a stochastic extremum-seeking algorithm for one-dimensional and multivariate optimization of static systems. Extremum-seeking algorithms estimate the optimum value of a function using perturbation signals. The authors propose three schemes (a basic scheme, an annealing parameter scheme, and a high-pass filter scheme) for the one-parameter problem and one scheme (a high-pass filter scheme) for the multivariate problem. These methods employ Wiener processes for the perturbation signals. In this paper, the proposed methods are shown to converge by means of a stability analysis of stochastic systems. The paper presents some numerical examples to demonstrate the effectiveness of the methods.
• Simultaneous estimation of vehicle sideslip angle and tire-road friction coefficient

  Momoko Yoshida, Yuh Yamashita

  2013 PROCEEDINGS OF SICE ANNUAL CONFERENCE (SICE) 1586 - 1591 1550-0322 2013 [Refereed][Not invited]
   

  We simultaneously estimate the vehicle sideslip angle and tire-road friction coefficient from generally given information from various sensors by using the differences in tire characteristics. In most previous studies, a linear vehicle model for determining the lateral force has been used, whereas we use a nonlinear model. Furthermore, we use Levant's exact differentiator to determine the yaw angular acceleration from the yaw rate in real time. The proposed method can accurately estimate the vehicle sideslip angle and provide real-time information about road surface conditions without the need to use an expensive real-time kinematic global positioning system sensor.
• Stability and Stabilization of Homogeneous Stochastic Systems

  Kenta Hoshino, Yuh Yamashita, Yuki Nishimura, Daisuke Tsubakino

  2013 IEEE 52ND ANNUAL CONFERENCE ON DECISION AND CONTROL (CDC) 1229 - 1234 0743-1546 2013 [Refereed][Not invited]
   

  This study considers homogeneous stochastic systems and shows their stability and stabilization. We define a homogeneous stochastic system as an extension of a homogeneous deterministic system. We show that homogeneous systems can exhibit exponential stability or finite-time stability according to the degree of homogeneity. Further, we show a control law for the stabilization of homogeneous stochastic control systems. Numerical examples of stable homogeneous systems and the stabilization of a homogeneous control system are also presented.
• Control of two-wheeled mobile robot via homogeneous semiconcave control Lyapunov function

  Shunsuke Kimura, Hisakazu Nakamura, Yuh Yamashita

  IFAC Proceedings Volumes (IFAC-PapersOnline) 9 (1) 92 - 97 1474-6670 2013 [Refereed][Not invited]
   

  Semiconcave control Lyapunov functions for globally asymptotic stabilizing controllable systems are available. However, a semiconcave control Lyapunov function for nonholonomic systems has not been proposed yet. For a two-wheeled mobile robot, we construct a homogeneous semiconcave control Lyapunov function and a control law with the function. The advantages of the proposed method are confirmed by computer simulation. © IFAC.
• Constructive design method of stochastic continuous feedback laws for stabilization of deterministic nonlinear systems

  Kenta Hoshino, Yuki Nishimura, Yuh Yamashita, Daisuke Tsubakino

  2013 AMERICAN CONTROL CONFERENCE (ACC) 2013 Vol.8 6424 - 6429 0743-1619 2013 [Refereed][Not invited]
   

  The purpose of this paper is to present a constructive design method of a stochastic feedback law for a deterministic nonlinear affine system. This design method gives a feedback law in the case that a randomized system is given as a Stratonovich-type stochastic differential equation, based on a result of Wong and Zakai. It is proved that a designed feedback law can globally asymptotically stabilize a randomized system with probability one. The design method employs a notion of a stochastic control Lyapunov function and the so-called Sontag's formula. The method in this paper aims the stabilization of nonholomic systems and non-Euclidean systems, which cannot be stabilized by any continuously differentiable time-invariant feedback laws. We can obtain a continuous feedback law for a state variable in the stabilization of such systems.
• Stochastic asymptotic stabilizers for deterministic input-affine systems based on stochastic control lyapunov functions

  Yûki Nishimura, Kanya Tanaka, Yuji Wakasa, Yuh Yamashita

  IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E96-A (8) 1695 - 1702 1745-1337 2013 [Refereed][Not invited]
   

  In this paper, a stochastic asymptotic stabilization method is proposed for deterministic input-affine control systems, which are randomized by including Gaussian white noises in control inputs. The sufficient condition is derived for the diffusion coefficients so that there exist stochastic control Lyapunov functions for the systems. To illustrate the usefulness of the sufficient condition, the authors propose the stochastic continuous feedback law, which makes the origin of the Brockett integrator become globally asymptotically stable in probability. Copyright © 2013 The Institute of Electronics, Information and Communication Engineers.
• Stability and stabilization of homogeneous stochastic systems

  Kenta Hoshino, Yuh Yamashita, Yûki Nishimura, Daisuke Tsubakino

  Proceedings of the IEEE Conference on Decision and Control 1229 - 1234 0191-2216 2013 [Refereed][Not invited]
   

  This study considers homogeneous stochastic systems and shows their stability and stabilization. We define a homogeneous stochastic system as an extension of a homogeneous deterministic system. We show that homogeneous systems can exhibit exponential stability or finite-time stability according to the degree of homogeneity. Further, we show a control law for the stabilization of homogeneous stochastic control systems. Numerical examples of stable homogeneous systems and the stabilization of a homogeneous control system are also presented. © 2013 IEEE.
• Boundary control of a cascade of two parabolic PDEs with different diffusion coefficients

  Daisuke Tsubakino, Miroslav Krstic, Yuh Yamashita

  Proceedings of the IEEE Conference on Decision and Control 3720 - 3725 0191-2216 2013 [Refereed][Not invited]
   

  In this paper, a state feedback control law is proposed for boundary coupled two different one-dimensional parabolic partial differential equations (PDEs). The control input is assumed to act only at a boundary of one side. The feedback law is designed based on the backstepping method. As a novelty of this paper, a state transformation involving a 'discontinuous' integral kernel is introduced in order to handle the difference of diffusion coefficients. This enables us to develop a well-posed backstepping framework for cascades of parabolic PDEs and an exponentially stabilizing controller is derived. The performance of the proposed controller is also validated by numerical simulation. ©2013 IEEE.
• Digital Control with One Sampling Delay Focused on Value of Control Lyapunov Function of Continuous-time System

  Shu Kusano, Yuh Yamashita

  Transactions of the Society of Instrument and Control Engineers 計測自動制御学会 ; [196-]- 48 (12) 889 - 897 0453-4654 2012/12 [Refereed][Not invited]
  
• Numerical Computation of Families of Dissipative Boundaries for Two-Dimensional Gradient-Like Morse-Smale Dynamical Systems

  Yukishige Izue, Ryuji Enomoto, Yuh Yamashita

  IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences J95-A (3) 2011JAP1066  1881-0195 2012/03 [Refereed][Not invited]
  
• Vibration suppression of mass-spring-damper system with dynamic dampers using IDA-PBC

  Takashi Aoki, Yuh Yamashita, Daisuke Tsubakino

  IFAC Proceedings Volumes (IFAC-PapersOnline) 45 (19) 42 - 47 1474-6670 2012 [Refereed][Not invited]
   

  In this paper, we propose a vibration suppression control method for a mass-spring-damper system with one or two dynamic damper(s). The feedback is designed by the interconnection and damping assignment passivity-based control, where the system is transformed to a system having a skyhook damper with an artificial modification of the structure matrix. The feedback is expressed by a function of the relative displacements and velocities. The proposed control method can suppress the influences of the floor vibration and the disturbance force acting on the main body, simultaneously. © 2012 IFAC.
• Navigation Function of Mobile Robots for Formation Driving

  Masahiro Yamada, Yuh Yamashita, Daisuke Tsubakino

  2012 IEEE INTERNATIONAL CONFERENCE ON CONTROL APPLICATIONS (CCA) 1590 - 1595 1085-1992 2012 [Refereed][Not invited]
   

  This paper investigates a vehicle formation control based on the following of a leader by nonholonomic mobile robots with two driving wheels. In this research, we propose a method for creating continuous and non-differentiable navigation functions, from which we derive a formation control law for each robot. The non-differentiability of the proposed navigation function removes the singularity encountered by conventional methods. The stability condition of a formation based on leader-following has been demonstrated by Tanner et al. as "Leader-to-Formation Stability" (LFS) [1]. In this paper, we assess the LFS property by regarding the navigation function as a LFS Lyapunov function.
• Control Law for Multiple Obstacle Avoidance of Four-wheeled Vehicle with Limited Steering Angle by Multilayer Minimum Projection Method

  Ryo Nonaka, Yuh Yamashita, Daisuke Tsubakino

  2012 IEEE INTERNATIONAL CONFERENCE ON CONTROL APPLICATIONS (CCA) 1578 - 1583 1085-1992 2012 [Refereed][Not invited]
   

  Maintaining control of a mobile robot in a space punctuated by obstacles is known to be a difficult problem. It is generally necessary to avoid such obstacles and find as short a route as possible to a goal. In this paper, we approach such a problem by proposing a design method for a navigation function to a given goal point, assuming that we know the location and shape of the obstacles. We then obtain a control law for a four-wheeled vehicle from a control Lyapunov function extended from this navigation function. Four-wheeled vehicles, such as cars, cannot move sideways due to their nonholonomic constraint. The control law proposed in this paper clears the nonholonomicity and enables us to consider the direction of the vehicle and its steering angle limitation using the backstepping method with our navigation function. We also describe some experimental results of the proposed method for a small four-wheeled vehicle.
• A Search Algorithm for Control Lyapunov Functions Using Radial Basis Function Networks

  Takayuki Tsuzuki, Taiki Yagi, Kazunobu Yoshida, Yuh Yamashita

  Proceedings of SICE Annual Conference 2011 390 - 394 2011/09 [Refereed][Not invited]
  
• Novel ODE-Type Smith Predictor for Nonlinear Control Systems with Delay

  Xuanxuan TENG, Yuh YAMASHITA

  SICE Journal of Control, Measurement, and System Integration The Society of Instrument and Control Engineers 4 (5) 380 - 386 1882-4889 2011/09 [Refereed][Not invited]
   

  This paper proposes a novel ODE-type Smith predictor for nonlinear control systems with transmission delays. The presence of time delays in the transmission of the control signals and the sensor signals may severely affect the performance of the closed-loop system and prevent the successful application of established nonlinear control methodologies. First, we investigate a backstepping interpretation of Smith predictors for linear time-variant (LTV) systems in the state space. Second, we propose a new nonlinear Smith predictor, the error dynamics of which is locally stabilized by another Smith predictor for the LTV systems. The Smith predictor can reduce the computational cost of the controller, because integral equations, which should be solved at each time in previously proposed predictive controllers, are replaced by inner-product operations.
• Schrodinger Equations Constructing Approximate Solutions to Infinite-Horizon Optimal Regulators

  Yuki Nishimura, Kanya Tanaka, Yuji Wakasa, Yuh Yamashita

  Transactions of the Japan Society for Industrial and Applied Mathematics 一般社団法人 日本応用数理学会 21 (3) 197 - 209 0917-2246 2011/03 [Refereed][Not invited]
   

  Pontryagin formalized optimal control problems as canonical systems, which are concepts from analytic mechanics. Recently, a canonical quantization method for optimal control problems was proposed. In this paper, we derive a sufficient condition that particular solutions to the canonical quantized optimal regulator problems converge to strict solutions to the original optimal control problems with infinite-time horizons. Further, we discuss possibility that the canonical quantization method yields useful approximate methods for nonlinear optimal regulator problems.
• Static Nonsmooth Control Lyapunov Function Design via Dynamic Extension

  Takahiro Yamazaki, Yuh Yamashita, Hisakazu Nakamura

  2011 50TH IEEE CONFERENCE ON DECISION AND CONTROL AND EUROPEAN CONTROL CONFERENCE (CDC-ECC) 7573 - 7578 2011 [Refereed][Not invited]
   

  In this paper, we propose a method to obtain a control Lyapunov function (CLF) by the reduction of a CLF of an augmented system with a dynamic compensator. For asymptotically stabilizing control, dynamic compensators are not necessary in most of the cases. However, in some cases, we can easily design a stabilizing control law using a dynamic compensator. Therefore, a constructive design method using a static controller via a dynamic controller has advantages and is preferable in practice. In this paper, we assume that a CLF has been designed on an extended state space with a dynamic compensator, and show that taking minimum values of the CLF on the extended state space gives a nonsmooth CLF on the original state space. This method can be considered as an extension of the minimum projection method[1], [2]. We also show that the obtained CLF fulfills Lipschitz continuity and local semiconcavity if the original CLF on the extended state space is Lipschitz continuous and locally semiconcave. The effectiveness of the proposed method is demonstrated by an example.
• Schrödinger equations for constructing infinite time horizon optimal regulators

  Yuki Nishimura, Kanya Tanaka, Yuji Wakasa, Yuh Yamashita

  IFAC Proceedings Volumes (IFAC-PapersOnline) 18 (1) 8058 - 8063 1474-6670 2011 [Refereed][Not invited]
   

  In this paper, we propose a new method for constructing approximate value functions for nonlinear optimal regulator problems with infinite time horizons. We consider a canonical quantization, which is an operation to change classical mass systems to quantum mass systems. First, we apply the canonical quantization to mass systems equivalent to the optimal regulator systems. Second, we construct approximate optimal regulators by using the canonical quantized mass systems. Third, we clarify the conditions under which approximate solutions converge to the strict solutions. In addition, we demonstrate some examples with one-dimensional systems. © 2011 IFAC.
• Passivity based control of bilateral teleoperators with time delay using low-pass filters

  Naoyoshi Ohkawa, Yuh Yamashita

  IFAC Proceedings Volumes (IFAC-PapersOnline) 18 (1) 3274 - 3279 1474-6670 2011 [Refereed][Not invited]
   

  Bilateral teleoperators, designed within the passivity framework using the concepts of scattering transformation and two port network theory, provide robust stability in the constant delay condition in a network. In this paper, we propose a new coordination architecture for bilateral teleoperation in which static feedback gains in the master and slave robots are replaced by dynamic feedbacks using nonlinear low-pass filters. This architecture can select low-frequency gain and high-frequency gain independently. We can select the cut-off frequencies of the master block and slave block independently. We show the stability of our system and the ultimate boundedness of the position error between the master manipulator and the slave manipulator trajectories using a Lyapunov Krasovskii functional, in free motion with transmission time delay. This architecture guarantees accurate position tracking of the two robots in free motion with transmission time delay. Simulation results are presented that demonstrate the effectiveness of the proposed architecture for position and force tracking control. © 2011 IFAC.
• Novel extremum seeking algorithm using Wiener process

  Kenta Hoshino, Yuh Yamashita

  2011 19th Mediterranean Conference on Control and Automation, MED 2011 886 - 891 2011 [Refereed][Not invited]
   

  We propose a new stochastic continuous time extremum seeking algorithm. The proposed algorithm is simpler to use than conventional stochastic continuous time extremum seeking algorithms. The proposed algorithm uses the Wiener process directly to extract gradients of objective functions. Three schemes, i.e., the simple scheme, the annealing parameter scheme, and the high-pass-filter scheme, are described. We develop a method for estimating the time evolution of the probability density of the solution of the system in the simple scheme. The stability analysis is discussed for the high-pass filter scheme. It is shown that the extreme value of the system is obtained with the proposed system in simulation results. © 2011 IEEE.
• Novel ODE-type nonlinear Smith predictor for networked control systems with time-varying delay

  Xuanxuan Teng, Yuh Yamashita

  2011 19th Mediterranean Conference on Control and Automation, MED 2011 19 - 24 2011 [Refereed][Not invited]
   

  This paper discusses the stability analysis of networked control systems (NCSs) with time-varying delays. In an NCS, the presence of time delays in the transmission may severely affect the performance of the closed-loop system and prevent the successful application of established nonlinear control methodologies. First, we present the backstepping interpretation of Smith predictors for linear time-variant systems in the state space. Second, we present a design and stability analysis for the control of a nonlinear Smith predictor and propose a new control scheme. The Smith predictor provides a set of future control predictions to make the closed-loop system achieve the desired control performance. © 2011 IEEE.
• Global Asymptotic Stabilization for a Nonlinear System on a Manifold via a Dynamic Compensator

  Takayuki TSUZUKI, Yuh YAMASHITA

  Transactions of the Society of Instrument and Control Engineers The Society of Instrument and Control Engineers 46 (10) 598 - 606 0453-4654 2010/10 [Refereed][Not invited]
   

  The purpose of this paper is to solve a global asymptotic stabilization problem for a nonlinear control system on a manifold with a complete metric. As well known, a system on a noncontractible manifold is not globally asymptotically stabilizable via a continuous feedback law. This problem results from the existence of multiple singular points of such a controlled system. It is shown that if all singular points can be assigned to a subspace of the extended state space using a dynamic compensator and a continuous feedback except for at most one jump, then the augmented system becomes globally asymptotically stable. Moreover, a method for stabilization is developed using a dynamic compensator and a global control Lyapunov function for an input-affine system. Finally, we propose a method for constructing the control Lyapunov function for a system such that the dimension of the coefficient matrix of the input is equal to the dimension of the state.
• A sufficient condition for local semiconcavity of value function of nonlinear optimal regulator

  Takayuki Tsuzuki, Yuh Yamashita

  Proceedings of SICE Annual Conference 2010 1559 - 1562 2010/08 [Refereed][Not invited]
  
• Observer-Based Delayed Feedback Control Stabilizing Unstable Periodic Orbits of Continuous-Time Chaotic Systems

  Yuh Yamashita

  Proceeding of IFAC Workshop on Periodic Control Systems 2010 75 - 80 2010/08 [Refereed][Not invited]
  
• Numerical Computation of Regular Dissipative Boundaries for Two-Dimensional Gradient-Like Morse-Smale Dynamical Systems

  Yukishige Izue, Ryuji Enomoto, Yuh Yamashita

  IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences 一般社団法人電子情報通信学会 J93-A (2) 119 - 126 0913-5707 2010/02 [Refereed][Not invited]
   

  本研究の目的は,大域コンパクトアトラクタをもつような任意の二次元こう配的Morse-Smale力学系に対して,Conleyの意味におけるリヤプノフ関数を構成するための有効な方法を見出すことである.最初にいくつかの特徴的な散逸境界(リヤプノフ関数の水準面の境界)を求め,それらを組み合わせてリヤプノフ関数を構成したい.本論文では,その第一ステップとして,チューブと呼ばれる概念を用いて散逸境界を数値的に算定するためのアルゴリズムを提案し,数値例を用いてその有効性を確認する.
• Novel ODE-type Nonlinear Smith Predictor for Networked Control Systems

  Xuanxuan Teng, Yuh Yamashita

  2010 IEEE INTERNATIONAL CONFERENCE ON CONTROL APPLICATIONS 1773 - 1778 1085-1992 2010 [Refereed][Not invited]
   

  This paper discusses the stability analysis of networked control systems (NCSs) with transmission delays. In an NCS, the presence of time delays in the transmission may severely affect the performance of the closed-loop system and prevent the successful application of established nonlinear control methodologies. First, we present the backstepping interpretation of Smith predictors for linear time-variant systems in the state space. Second, we present a design and stability analysis for the control of a nonlinear Smith predictor and propose a new control scheme. The Smith predictor provides a set of future control predictions to make the closed-loop system achieve the desired control performance.
• Minimum Projection Method for nonsmooth control Lyapunov function design on general manifolds

  Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani

  SYSTEMS & CONTROL LETTERS 58 (10-11) 716 - 723 0167-6911 2009/10 [Refereed][Not invited]
   

  Asymptotic stabilization on noncontractible manifolds is known as a difficult control problem. On the other hand, an important fact is every control system that is globally asymptotically stabilizable at a desired equilibrium must have nonsmooth control Lyapunov functions. This paper considers the problem of construction of nonsmooth control Lyapunov functions on general manifolds, and we propose a nonsmooth control Lyapunov function design method called the 'Minimum Projection Method'. The proposed method considers a simple-structured smooth manifold associated with the original manifold by a surjective immersion, and then a control Lyapunov function defined on the simple-structured manifold is projected to the original manifold. A function on the original manifold is thus obtained. In this paper, we prove that the control system on another manifold associated with a surjective immersion is determined uniquely, and the resulting function by the proposed method is a nonsmooth control Lyapunov function on the original manifold. The effectiveness of the proposed method is confirmed by examples. (C) 2009 Elsevier B.V. All rights reserved.
• Homogeneous Stabilization for Input Affine Homogeneous Systems

  Nami Nakamura, Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani

  IEEE TRANSACTIONS ON AUTOMATIC CONTROL 54 (9) 2271 - 2275 0018-9286 2009/09 [Refereed][Not invited]
   

  Dilated homogeneous systems are local canonical forms of nonlinear control systems. For input affine homogeneous systems, existence of continuous homogeneous stabilizing controllers is equivalent to existence of differentiable homogeneous control Lyapunov functions. In this technical note, we propose an homogeneous stabilizing controller and an homogeneous inverse optimal controller for multi-input affine homogeneous systems with given homogeneous control Lyapunov functions.
• Asymptotic stabilization of nonlinear systems on general manifolds via minimum projection method

  Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani

  Proceedings of European Control Conference 2009 2757 - 2762 2009/08 [Refereed][Not invited]
  
• Construction Method of Approximate Stochastic Lyapunov Functions using Quantization of Markov Process

  Yuki Nishimura, Yuh Yamashita

  Transactions of the Institute of Systems, Control and Information Engineers 一般社団法人 システム制御情報学会 22 (8) 295 - 302 1342-5668 2009/08 [Refereed][Not invited]
   

  The existence of stochastic Lyapunov functions assures that the systems are stable in probability. However, general scheme of obtaining stochastic Lyapunov functions has not been introduced yet. This paper extends the authors' previous method[21] obtaining Lyapunov functions for deterministic cases to stochastic cases. In the method, difference-approximation scheme[6,10] and quantization of Markov processes[1,14] are used to approximate Lyapunov equations by linear quantum-like equations. We propose a method of obtaining approximate stochastic Lyapunov functions for nonlinear stochastic systems by superimposing the eigenfunctions of the quantum-like equations.
• Construction method of Lyapunov functions based on eigen analysis

  Yuki Nishimura, Yuh Yamashita, Kanya Tanaka, Yuji Wakasa

  Proceedings of 2009 ICCAS-SICE 691 - 694 2009/08 [Refereed][Not invited]
  
• Stabilization Problems of Nonlinear Systems using Feedback laws with Wiener Processes

  Yuki Nishimura, Kazuki Takehara, Yuh Yamashita, Kanya Tanaka, Yuji Wakasa

  PROCEEDINGS OF THE 48TH IEEE CONFERENCE ON DECISION AND CONTROL, 2009 HELD JOINTLY WITH THE 2009 28TH CHINESE CONTROL CONFERENCE (CDC/CCC 2009) 7363 - 7368 0743-1546 2009 [Refereed][Not invited]
   

  This paper proposes a method to stabilize the origins of deterministic dynamical systems by state feedback control laws with Wiener processes. First, we obtain Ito-type stochastic dynamical systems by randomizing ordinary differential equation systems. Second, we design the diffusion coefficients. Then, we obtain Sontag-type global asymptotically stabilizers based on the stochastic control Lyapunov functions. Moreover, we show the usefulness of our results by some examples, i.e., systems with noncontractible state spaces and nonholonomic systems.
• Homogeneous stabilization for input affine homogeneous systems

  Nami Nakamura, Hisakazu Nakamura, Yuh Yamashita

  IEEE Transactions on Automatic Control 54 (9) 2271 - 2275 0743-1546 2009 [Refereed][Not invited]
   

  In this paper, we propose an homogeneous stabilizing controller for input-affine homogeneous systems. Moreover, we provide an homogeneous inverse optimal controller.
• Global Asymptotical Stabilization of Morse-Smale Systems Using Weak Control-Lyapunov Functions

  Gou NISHIDA, Takayuki TSUZUKI, Hisakazu NAKAMURA, Yuh YAMASHITA

  SICE Journal of Control, Measurement, and System Integration 公益社団法人 計測自動制御学会 2 (1) 43 - 49 1882-4889 2009/01 [Refereed][Not invited]
   

  This paper proposes a method of constructing weak control-Lyapunov functions for nonlinear systems by introducing a topological geometric assumption called a Morse-Smale system. A Lyapunov function is one of the most important tools to study stability and stabilization of nonlinear systems. However, a general way of finding Lyapunov functions has not been found yet. First, we confirm there is a weak Lyapunov function for Morse-Smale systems. Next, we define the escapability for singular structures of the weak Lyapunov function. If all singular structures are escapable, then the Morse-Smale system is a globally asymptotically stabilizable one. Finally, we present the method of constructing a set of weak control-Lyapunov functions to achieve global stabilization. The method is described in terms of a recursive sequence of singular structures. We call the sequence a weak Lyapunov filtration.
• Stabilization problems of nonlinear systems using feedback laws with wiener processes

  Yuki Nishimura, Kazuki Takehara, Yuh Yamashita, Kanya Tanaka, Yuji Wakasa

  Proceedings of the IEEE Conference on Decision and Control 7363 - 7368 0191-2216 2009 [Refereed][Not invited]
   

  This paper proposes a method to stabilize the origins of deterministic dynamical systems by state feedback control laws with Wiener processes. First, we obtain Ito-type stochastic dynamical systems by randomizing ordinary differential equation systems. Second, we design the diffusion coefficients. Then, we obtain Sontag-type global asymptotically stabilizers based on the stochastic control Lyapunov functions. Moreover, we show the usefulness of our results by some examples, i.e., systems with noncontractible state spaces and nonholonomic systems. ©2009 IEEE.
• Stochastic Lyapunov Function Design using Quantization of Markov Process

  Proceedings of 47th IEEE Conference on Decision and Control 3475 - 3480 2008 [Not refereed][Not invited]
  
• Stabilization of nonlinear systems using weak-control-Lyapunov functions

  NISHIDA G.

  Proc. the 17th IFAC World Congress, Seoul, 2008 6190 - 6195 2008 [Not refereed][Not invited]
  
• Global asymptotic stabilization for a nonlinear system on a manifold via a dynamic compensator

  Proceedings of 17th IFAC World Congress 6178 - 6183 2008 [Not refereed][Not invited]
  
• Lyapunov Function Design using Quantization of Markov Process

  Yuki Nishimura, Yuh Yamashita

  IFAC Proceedings Volumes 41 (2) 2808 - 2813 1474-6670 2008
• Construction of Lyapunov Function Using Quantization of Markov Process

  Yuki NISHIMURA, Yuh YAMASHITA

  Transactions of the Society of Instrument and Control Engineers 44 (1) 26 - 35 2008 [Refereed][Not invited]
  
• Inverse optimal control for nonlinear systems with input constraints

  Nami Nakamura, Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani

  Proceedings of 2007 European Control Conference 5376 - 5382 2007/07 [Refereed][Not invited]
  
• Seeking Control Lyapunov-Morse Functions Using Genetic Programming for Global Asymptotical Stabilization of Nonlinear Systems

  Takayuki TSUZUKI, Kousuke KUWADA, Yuh YAMASHITA

  Transactions of the Society of Instrument and Control Engineers 計測自動制御学会 43 (2) 85 - 92 0453-4654 2007/02 [Refereed][Not invited]
  
• Homogeneous eigenvalue analysis for complex homogeneous systems

  Nami Nakamura, Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani

  IFAC Proceedings Volumes (IFAC-PapersOnline) 7 (1) 107 - 112 1474-6670 2007 

  In this paper, we analyze the stability of complex homogeneous systems by homogeneous eigenvalues. First, we redefine the complex homogeneity. Second, we obtain some properties of complex homogeneous functions, complex homogeneous vector fields, and complex homogeneous systems. Finally, we analyze the stability of complex homogeneous systems by homogeneous eigenvalues. Copyright © 2007 IFAC.
• Homogeneous stabilization for input-affine homogeneous systems

  Nami Nakamura, Hisakazu Nakamura, Yuh Yamashita

  PROCEEDINGS OF THE 46TH IEEE CONFERENCE ON DECISION AND CONTROL, VOLS 1-14 3770 - + 0743-1546 2007 [Refereed][Not invited]
   

  In this paper, we propose an homogeneous stabilizing controller for input-affine homogeneous systems. Moreover, we provide an homogeneous inverse optimal controller.
• State Feedback Stabilization for Distributed Parameter Systems of Parabolic Type with Adaptive Observers

  OHMURO Akira, YAMASHITA Yuh, SHIMA Masasuke

  Transactions of the Society of Instrument and Control Engineers The Society of Instrument and Control Engineers 43 (10) 901 - 908 0453-4654 2007 [Not refereed][Not invited]
   

  This paper proposes a design method of stabilizing state feedback for distributed parameter systems of parabolic type with adaptive observers. The distributed parameter system with unknown coefficients is described by evolution equations in Hilbert space. The structure of adaptive observer using filtered values generated from input and output is stated. Moreover, control law using estimates of unknown coefficients is derived. Finally, by assuming the persistency of excitation, stability of the proposed control system is shown.
• Optimal control of formation flight based on MLD systems

  Miao Du, Yuh Yamashita

  PROCEEDINGS OF THE 2007 IEEE CONFERENCE ON CONTROL APPLICATIONS, VOLS 1-3 1292 - 1297 1085-1992 2007 [Refereed][Not invited]
   

  In this paper, formation flight is modeled as a mixed logical dynamical (MLD) system, which is described by linear equations subject to linear inequalities involving real and integer variables. This model is built by discretizing the continuous-time nonlinear kinematical equations of formation flight system through the Euler method, quantizing its physical input variables, and integrating operating constraints. The control objective is to maintain the relative positions and orientations between aircraft close to their desired values to keep a formation geometry without potential collisions despite the maneuvering of the leader. The resulting MLD system of formation flight can be governed by the mixed integer predictive control (MIPC) law, and the optimal predictive control input can be obtained by solving an equivalent mixed integer linear programming (MILP) problem. This MLD model essentially considers the three dimensional motion of aircraft. The effectiveness of this method is demonstrated by simulation results.
• Homogeneous eigenvalue analysis for complex homogeneous systems of degree (l,l)

  Nami Nakamura, Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani

  PROCEEDINGS OF SICE ANNUAL CONFERENCE, VOLS 1-8 1238 - + 2007 [Refereed][Not invited]
   

  In this paper, we analyze the stability of complex homogeneous systems of degree (l, l) by homogeneous eigenvalues. First, we define homogeneous eigenvalues and homogeneous eigenvectors for complex homogeneous systems of degree (l, l). Then, we obtain solutions on homogeneous eigenvectors. Convergence of the solutions depends not only on homogeneous eigenvalues but also on homogeneous eigenvectors. Moreover, solutions on homogeneous eigenvectors never vibrate. Hence, it may not be appropriate to assign complex analytic homogeneous systems to real analytic homogeneous systems in complex transformation.
• Global asymptotic stabilization of nonlinear system with multiple singular points using changeover of control Lyapunov-Morse function

  Kazuki Takeharai, Takayuki Tsuzuki, Yuh Yamashita

  PROCEEDINGS OF SICE ANNUAL CONFERENCE, VOLS 1-8 104 - + 2007 [Refereed][Not invited]
   

  The purpose of this paper is to solve the global asymptotic stabilization problem of multi-input affine systems on general manifolds. It is known that if the control Lyapunov-Morse function (CLMF) satisfies some assumptions, the controlled system is globally asymptotically stablizable via the discontinuous feedback law derived from the CLMF. However, in some cases we cannot find CLMFs satisfying the assumption. In this paper, we perturb original CLMF and we change over the feedback laws derived from the original and perturbed CLMF under some rules. Moreover, a condition of global asymptotic stability of controlled system with feedback law is also obtained.
• Homogeneous eigenvalue analysis for complex homegeneous systems

  7th IFAC Symposium on Nonlinear Control Systems 415 - 420 2007 [Not refereed][Not invited]
  
• Semi-global output regulation of nonminimum-phase nonlinear systems via error feedback

  Yoshinori Hirose, Yuh Yamashita

  PROCEEDINGS OF SICE ANNUAL CONFERENCE, VOLS 1-8 1259 - + 2007 [Refereed][Not invited]
   

  We consider semi-global output regulation of single-input single-output nonminimum-phase nonlinear systems via error feedback. Onishi et al. introduced the method like backsteppings to solve some global output regulation problems via state feedback in non-minimum phase nonlinear systems. Yang et al. introduced a comprehensible idea to achieve semi-global stabilization via output feedback. We use these ideas. The regulator has saturation to prevent that sudden observation noise make the state of the whole system escape from origin neighborhood. This method requires the solvabilities of some partial differential equations and a linear growth condition.
• Homogeneous stabilization for input-affine homogeneous systems

  Nami Nakamura, Hisakazu Nakamura, Yuh Yamashita

  Proceedings of the IEEE Conference on Decision and Control 80 - 85 0191-2216 2007 [Refereed][Not invited]
   

  In this paper, we propose an homogeneous stabilizing controller for input-affine homogeneous systems. Moreover, we provide an homogeneous inverse optimal controller. © 2007 IEEE.
• On characteristic families of dissipative boundaries for two-dimensional gradient-like Morse-Smale controlled systems

  Ryuji Enomoto, Yukishige Izue, Yuh Yamashita

  2007 INTERNATIONAL CONFERENCE ON CONTROL, AUTOMATION AND SYSTEMS, VOLS 1-6 1487 - + 2007 [Refereed][Not invited]
   

  The method of gradient-like Morse-Smale controlled (GLMSC) systems is a systematic approach to solve global asymptotic stabilization problems for finite and nonlinear state equations. A GLMSC system is a closed loop system equipped with the structure of a gradient-like Morse-Smale flow. In general, the system has finitely many hyperbolic singular points of the vector field. Its global compact attractor can be represented as a normal CW-complex (CWC). For a fixed combination of hyperbolic singular points, there appear a vast number of corresponding CWCs with different structures. In this paper, we investigate an identification technique for these CWCs with the same singular point data and propose a notion of 'characteristic families of dissipative boundaries' for distinguishing a given CWC from others.
• Searching for control Lyapunov-Morse functions using genetic programming for global asymptotic stabilization of nonlinear systems

  Takayuki Tsuzuki, Kousuke Kuwada, Yuh Yamashita

  Proceedings of the 45th IEEE Conference on Decision and Control IEEE 5114 - 5119 0743-1546 2006/12 [Refereed][Not invited]
  
• Asymptotic Stability Analysis for Homogeneous Systems Using Homogeneous Eigenvalues

  Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani

  Proceedings of the 45th IEEE Conference on Decision and Control IEEE 4230 - 4235 2006/12 [Refereed][Not invited]
  
• Adaptive Observers of Distributed Parameter Systems of Parabolic Type

  Akira OHMURO, Yuh YAMASHITA, Masasuke SHIMA

  Transactions of the Society of Instrument and Control Engineers The Society of Instrument and Control Engineers 42 (10) 1100 - 1106 0453-4654 2006/10 [Refereed]
   

  This paper proposes a design method of adaptive observers for distributed parameter systems of parabolic type. For a distributed parameter system with unknown coefficients described by an evolution equation in Hilbert space, transformations of the state derives an input-output representation with filtered values. An adaptive law and a state observer are obtained, where the convergence of parameter error is evaluated by using the Lyapunov function. Under the assumption of persistency of excitation, parameter-error convergence to zero is guaranteed.
• Stability Analysis of Homgoeneous Systems via Homogeneous Eigenvalues

  Hisakazu NAKAMURA, Yuh YAMASHITA, Hirokazu NISHITANI

  Transactions of the Society of Instrument and Control Engineers The Society of Instrument and Control Engineers 42 (8) 894 - 901 0453-4654 2006/08 [Refereed][Not invited]
   

  This paper focuses on the problem of stability of homogeneous systems with dilation. First, we propose 'homogeneous eigenvalue' for the homogeneous systems. Next, we analyze stability of the homogeneous systems using the homogeneous eigenvalues, and we show that the positive homogeneous eigenvalues imply instability. Finally, we show effectiveness of the proposed method by examples.
• Existence of Homogeneous Eigenvalues for Homogeneous Systems

  Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani

  Proc. MTNS 2006 2799 - 2804 2006/07 [Refereed][Not invited]
  
• Stabilization Problem of 1-Input Underactuated Mechanics

  Yuki Nishimura, Yuh Yamashita

  17th International Symposium on Mathematical Theory of Networks and Systems 1018 - 1023 2006/07 [Refereed][Not invited]
  
• Global Asymptotic Stabilization of Multi-Input Affine Systems by Using Control Lyapunov-Morse Function

  Takayuki Tsuzuki, Yuh Yamashita

  17th International Symposium on Mathematical Theory of Networks and Systems 22 - 26 2006/07 [Refereed][Not invited]
  
• Adaptive Observers of Distributed Parameter Systems of the Parabolic Type with Unknown Parameters

  Akira Ohmuro, Yuh Yamashita

  17th International Symposium on Mathematical Theory of Networks and Systems 2053 - 2058 2006/07 [Refereed][Not invited]
  
• Numerical Computation of Dissipative Boundaries for Two-Dimensional Gradient-Like Morse-Smale Dynamical Systems

  Yukishige Izue, Ryuji Enomoto, Yuh Yamashita

  17th International Symposium on Mathematical Theory of Networks and Systems 2043 - 2047 2006/07 [Refereed][Not invited]
  
• Postural Stability Analysis of Compass-like Biped Robot Model

  Yuji Hosokawa, Hisakazu Nakamura, Hirokazu Nishitani, Yuh Yamashita

  Journal of the Robotics Society of Japan The Robotics Society of Japan 24 (2) 232 - 239 0289-1824 2006/02 [Refereed][Not invited]
   

  This paper focuses on the problem of postural stability of a biped robot. We consider a compass-like biped model and analyze its postural stability based on the energy dissipation when the idling leg collides against the ground surface. We calculate the amount of energy dissipation by using rigid dynamics. We propose a novel criterion PSC (Postural Stability Criterion) that judges postural stability of the robot. Finally the effectiveness of the proposed criterion with two other indexes is demonstrated by computer simulation.
• Stabilization of nonlinear planer systems using homogeneous eigenvalues

  Hisakazu Nakamura, Gou Nishida, Hirokazu Nishitani, Yuh Yamashita

  2006 SICE-ICASE INTERNATIONAL JOINT CONFERENCE, VOLS 1-13 33 - + 2006 [Not refereed][Not invited]
   

  Homogeneous systems play important roles in nonlinear control theory. We proposed homogeneous eigenvalues, and provided sufficient conditions for asymptotic stability using homogeneous eigenvalue analysis in the previous papers. In this paper, we prove that there exist a homogeneous system which has uncountable infinite homogeneous eigenvalues. Moreover, we introduce the definition of the oscillation in nonlinear systems and prove the condition for oscillation. Finally, we construct the controller which does not oscillate each solution of the controlled system.
• Global Asymptotic Stabilization by Using Control Lyapunov-Morse Functions

  Takayuki TSUZUKI, Yuh YAMASHITA

  Transactions of the Society of Instrument and Control Engineers The Society of Instrument and Control Engineers 42 (6) 643 - 650 0453-4654 2006 

  The purpose of this paper is to solve the global asymptotic stabilization problem for nonlinear systems on general manifolds. It is known that if the state space of a control system is not contractible, the system is not globally asymptotically stabilizable via C¹ feedback law, because gradient-like flow on the non-contractible manifold demands multiple singular points. In this paper, we define a control Lyapunov-Morse function having multiple critical points using the concept of the Lyapunov-Morse function, which is a kind of complete Lyapunov functions for dynamical systems with multiple isolated singular points. We derive a discontinuous feedback law from the control Lyapunov-Morse function. Moreover, a condition for global asymptotic stability of the controlled system with the discontinuous feedback law is also obtained.
• Inverse Optimal Control for a Nonlinear System with an Input Constraint

  Nami KIDANE, Hisakazu NAKAMURA, Yuh YAMASHITA, Hirokazu NISHITANI

  Transactions of the Society of Instrument and Control Engineers 計測自動制御学会 42 (1) 26 - 34 0453-4654 2006/01 [Refereed][Not invited]
  
• Global finite-time control of wheeled mobile robots using homogeneous finite-time controllers

  Nakamura Hisakazu, Yamashita Yuh, Nishitani Hirokazu

  Proceedings of the Annual Conference of the Institute of Systems, Control and Information Engineers システム制御情報学会 6 231 - 231 2006 

  In this paper, we propose a global finite-time stabilizer for a wheeled mobile robot.Moreover, we analyze the oscillation of the controlled system using homogeneous eigenvalue analysis.Finally, we confirm the effectiveness of the proposed method by computer simulation.
• On the option pricing using stock prices and volatilities via time series analysis

  KIMOTO TAKAMORI, OHMURO AKIRA, YAMASHITA YUH

  Proceedings of the Annual Conference of the Institute of Systems, Control and Information Engineers システム制御情報学会 6 46 - 46 2006 

  確率的なダイナミカルシステムで表現される株価の変動モデルに対しては、今日まで時系列解析やオプション理論など、さまざまな研究がなされてきたが、それらを組み合わせたオプションプライシングなどの研究は、あまり行われていないのが現状である。そこで、時系列解析により得られる推定値のオプションプライシングへの適用を試みる。そのために、ARモデルとSVモデルによる株価の時系列解析と、Edgeworth展開により近似される確率密度関数を用いたオプションモデルの導出を行う。
• Asymptotic stability of homogeneous systems using homogeneous eigenvalues

  Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani

  PROCEEDINGS OF THE 45TH IEEE CONFERENCE ON DECISION AND CONTROL, VOLS 1-14 4234 - + 0743-1546 2006 [Refereed][Not invited]
   

  Homogeneous eigenvalue analysis is a useful tool for analysis of homogeneous systems. We obtained necessary conditions for asymptotic stability in our previous paper. However, any sufficient conditions are not obtained. In this paper, we introduce Euler sphere, and analyze the properties of solutions of homogeneous systems using dilations of Euler sphere. Moreover, we show the equivalence between a trajectory of a projection of a solution and a trajectory of a solution of a projection system. Then, we prove sufficient conditions for asymptotic stability of homogeneous systems. Finally, we demonstrate the effectiveness of the proposed method for a system which has an uncontrollable linear approximation.
• Complex homogeneous eigenvalues for complex homogeneous systems

  Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani

  Proc. of SICE Annual Conference 2005 3033 - 3036 2005/08 [Refereed][Not invited]
  
• GLOBAL ASYMPTOTIC STABILIZATION BY USING THE CONTROL LYAPUNOV FUNCTION

  Takayuki Tsuzuki, Yuh Yamashita, Ryuji Enomoto

  IFAC Proceedings Volumes (Proc. IFAC World Congress 2005) 38 (1) 640 - 645 1474-6670 2005/07 [Refereed][Not invited]
  
• On a topological condition for strongly asymptotically stable differential inclusions

  Yuh Yamashita, Takayuki Tsuzuki, Hisakazu Nakamura

  2005 44th IEEE Conference on Decision and Control & European Control Conference, Vols 1-8 5444 - 5449 0191-2216 2005 [Refereed][Not invited]
   

  In this paper, we will show that a system on a non-contractible manifold cannot be strongly asymptotically stabilized in Filippov's sense, even if discontinuous feedback is used. The fact is well-known for C-1 feedback case, and we extend it to the discontinuous feedback case. To consider the stabilization problem on a non-contractible manifold, the assumption convexity or upper semicontinuity is restrictive. We will propose a new type of differential inclusion without upper semicontinuity by defining a function indicating a rate of leaving from discontinuous set. By adopting the new differential inclusion, stabilization problems on non-contractible manifolds become possible for many cases.
• Grobal position and posture control of a two-wheeled mobile robot using a discontinuous homogeneous control

  H Nakamura, T Kaji, H Nishitani, Y Yamashita

  2005 IEEE INTERNATIONAL CONFERENCE ON CONTROL APPLICATIONS (CCA), VOLS 1AND 2 1569 - 1574 1085-1992 2005 [Not refereed][Not invited]
   

  This paper focuses on the problem of global stabilization of a two-wheeled mobile robot. We propose a global exponentially stabilizing controller for a two-wheel mobile robot based on the discontinuous finite-time homogeneous controller for chained systems. Moreover, we demonstrate the effectiveness of proposed method through an experiment using a "Khepera 2" mobile robot.
• Controller for a nonlinear system with an input constraint by using a control Lyapunov function I

  16th IFAC World Congress (CD-ROM) Th-E03-TO/4  2005 [Not refereed][Not invited]
  
• Nonlinear continuous-time reference governors for constrained nonlinear systems

  16th IFAC World Congress (CD-ROM) Fr-M08-TO/6  2005 [Not refereed][Not invited]
  
• Controller for a nonlinear system with an input constraint by using a control Lyapunov function II

  16th IFAC World Congress (CD-ROM) Th-E03-TO/5  2005 [Not refereed][Not invited]
  
• Controller Design for a Nonlinear System with an Input Constraint

  KIDANE Nami, NAKAMURA Hisakazu, YAMASHITA Yuh, NISHITANI Hirokazu

  計測自動制御学会論文集 計測自動制御学会 41 (3) 250 - 258 0453-4654 2005 [Not refereed][Not invited]
  
• Homogeneous eigenvalue analysis of homogeneous systems

  NAKAMURA H.

  16th IFAC World Congress, 2005 Mo-A11-TO/4  2005 [Not refereed][Not invited]
  
• Thinking State Estimation using Multiple Physiological Signals

  Taketoshi KUROOKA, Masato ANDO, Ippei HOSHI, Yuh YAMASHITA, Hirokazu NISHITANI

  The Human Factors in Japan 日本プラント・ヒューマンファクター学会 9 (2) 114 - 122 1349-4910 2005/01 [Refereed][Not invited]
  
• Globally Asymptotically Stable Attitude Control System of Satellite Using Nonlinear Observer

  YAMASHITA Yuh, NAKAMURA Hisakazu, NISHITANI Hirokazu

  計測自動制御学会論文集 計測自動制御学会 40 (11) 1071 - 1077 0453-4654 2004/11/30 [Not refereed][Not invited]
  
• Lyapunov functions for homogeneous differential inclusions

  Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani

  IFAC Proceedings Volumes (Part of special issue: 6th IFAC Symposium on Nonlinear Control Systems) 37 (13) 733 - 738 1474-6670 2004/09 [Refereed][Not invited]
  
• Human modeling and simulation for plant operations

  YH Jin, Y Yamashita, H Nishitani

  COMPUTERS & CHEMICAL ENGINEERING 28 (10) 1967 - 1980 0098-1354 2004/09 [Not refereed][Not invited]
   

  It is widely known that various types of human errors occur in the confused state of a plant operator's mind under abnormal situations. In order to understand the generation mechanism of these human errors in the circumstances of disturbances and equipment failures, we have developed a cognitive information-processing model incorporating the operator's physical and mental states. The operator model is installed on a PC and connected to a boiler plant simulator for training through a human-machine interface model that we also developed. Using this simulation environment we examine perceptual error in the monitoring mode and cognitive error in fault diagnosis during malfunctions. The simulation results coincide well qualitatively with observations of actual plant operations and simulator training. This operator model can be used to analyze the generation mechanism of various types of human errors from the viewpoint of cognitive information processing. Accordingly, we can study how to prevent human errors and evaluate the effects of various measures by running simulations. (C) 2004 Elsevier Ltd. All rights reserved.
• Computer aids for knowledge management in plant operations

  O Orapimpan, A Kurosaki, T Kurooka, Y Yamashita, H Nishitani

  INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH 43 (14) 3731 - 3740 0888-5885 2004/07 [Not refereed][Not invited]
   

  It is difficult to extract tacit knowledge in the workplace. In this paper, we apply video annotation to externalize the technologies and skills in plant operations. We have developed two prototype systems. The first is an interactive support system using multimedia, which offers functions for collecting "know-how" and "know-why" from on-site plant operations and for presenting this information as learning materials. The second is a system for evaluating emergency training results and for extracting common problems and lesson points. This system is useful for exploratory sequential data analysis of human behavior.
• 認知情報処理モデルを用いた異常診断におけるプラントオペレータの認知エラーの考察

  金 銀花, 山下 裕, 西谷 紘一

  ヒューマンファクターズ 日本プラント・ヒューマンファクター学会 9 (1) 27 - 37 1349-4910 2004/07 [Not refereed][Not invited]
  
• Controller design for a nonlinear system with inputs restricted to a direct product of Minkowski balls

  N Kidane, H Nakamura, Y Yamashita, H Nishitani

  2004 43RD IEEE CONFERENCE ON DECISION AND CONTROL (CDC), VOLS 1-5 4069 - 4074 0743-1546 2004 [Not refereed][Not invited]
   

  In this paper, we propose a continuous controller for a nonlinear system such that the inputs are restricted to a direct product of Minkowski balls. We also demonstrate the effectiveness of the controller by computer simulation.
• Inverse optimization for a nonlinear system with an input constraint

  N Kidane, Y Yamashita, H Nakamura, H Nishitani

  SICE 2004 ANNUAL CONFERENCE, VOLS 1-3 1210 - 1213 2004 [Not refereed][Not invited]
   

  In a previous work, we proposed controllers that do not maintain the direction of the Jurdjevic-Quinn controller for a nonlinear system such that the k-norm of inputs is less than one. In this paper, we provide inverse optimal regulators that hold the directions of the proposed controllers.
• Stabilization of a cascade-connected nonlinear system with an input constraint

  6th IFAC Symposium on Nonlinear Control Systems 341 - 346 2004 [Not refereed][Not invited]
  
• A Kansei design system for keyboard switch reaction forces using neural networks

  2nd International Conference on Artificial Intelligence in Engineering and Technology 318 - 321 2004 [Not refereed][Not invited]
  
• Stabilization of a cascade-connected nonlinear system with an input constraint

  H Nakamura, N Kidane, Y Yamashita, H Nishitani

  SICE 2004 ANNUAL CONFERENCE, VOLS 1-3 1874 - 1879 2004 [Not refereed][Not invited]
   

  this paper focuses on the problem of stabilization of a nonlinear system with an input constraint. We provide a universal control formula for a cascade-connected nonlinear system with an input constraint and confirm the effectiveness of proposed method by computer simulation.
• Observer-based Controller Design for Nonlinear DAE Systems

  KIDANE Nami, YAMASHITA Yuh, NISHITANI Hirokazu

  Transactions of the Society of Instrument and Control Engineers The Society of Instrument and Control Engineers Vol. 40 (No. 7) 721 - 728 0453-4654 2004 [Not refereed][Not invited]
   

  In this paper, we propose a design method of an observer-based controller for nonlinear differential algebraic equation (DAE) systems. We transform a DAE system to an explicit ordinary differential equation (ODE) system that is restricted to an invariant manifold by differentiating the original DAE repeatedly. If the DAE is non-regular, we add integrators to inputs to avoid impulse modes. We design a state feedback law that incorporates redundant state variables and an observer that estimates all of these variables simultaneously. We also give a set of sufficient conditions for the global stability of the control system. The efficiency of the controller is demonstrated by computer simulation.
• Developing a driving simulator and an assessment methodology to estimate a driver's mental state when distracted

  Hiroaki Kosaka, Akira Kurosaki, Atsushi Harada, Yuh Yamashita, Hirokazu Nishitani

  SAE Technical Papers Paper Number: 2004-01-0233  2004 [Not refereed][Not invited]
   

  In this paper, authors discuss a driving simulator that was developed to study a driver's mental state in a traffic accident occurring between vehicles at an intersection. The functions of the driving simulator and a video annotation system for analyzing human behavior and human cognitive processes are discussed. Also described is how to estimate a driver's mental state by using physiological indices when the driver is distracted in addition to the experimental plan established. Copyright © 2004 SAE International.
• Compensation of transmission delay and packet-loss in nonlinear remote-control system

  The 10th IFAC/IFORS/IMACS/IFIP Symposium on Large Scale Systems: Theory and Applications 627 - 632 2004 [Not refereed][Not invited]
  
• Modeling and Simulation of Plant Operator’s Fault Diagnosis Process

  Yinhua JIN, Yuh YAMASHITA, Hirokazu NISHITANI

  The Journal of the Society for Industrial Plant Human Factors of Japan 日本プラント・ヒュ-マンファクタ-学会 8 (2) 68 - 76 1342-4459 2004/01 [Refereed][Not invited]
  
• Controller design for a nonlinear system with inputs restricted to a direct product of Minkowski balls

  Nami Kidane, Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani

  Proceedings of the IEEE Conference on Decision and Control 4 4069 - 4074 0191-2216 2004 

  In this paper, we propose a continuous controller for a nonlinear system such that the inputs are restricted to a direct product of Minkowski balls. We also demonstrate the effectiveness of the controller by computer simulation.
• Homogeneous Finite-Time Control of Chained Systems

  NAKAMURA Hisakazu, YAMASHITA Yuh, NISHITANI Hirokazu

  Transactions of the Society of Instrument and Control Engineers The Society of Instrument and Control Engineers 39 (8) 717 - 725 0453-4654 2003 [Not refereed][Not invited]
   

  This paper focuses on the problem of stabilization of a chained-form nonholonomic system. We propose a time-invariant discontinuous finite-time homogeneous controller for the chained system. The controller has no singular point where the control inputs become infinite values. Using the characteristics of the homogeneous system, we can select the convergence speed of the controlled system. Namely, we can choose an exponentially stable system or a finite-time stable system. We designed the controller for a 3-state chained system and confirmed the superior performance of the controlled system by computer simulations.
• Finite-time stabilization of the high-order chained system

  H Nakamura, Y Yamashita, H Nishitani

  PROCEEDINGS OF THE 2003 AMERICAN CONTROL CONFERENCE, VOLS 1-6 4137 - 4142 0743-1619 2003 [Not refereed][Not invited]
   

  This research focuses on the problem of a stabilization of high-order chained-form nonholonomic system. We propose a finite-time discontinuous controller for the chained system. The controller is derived by using a high-order homogeneous finite-time control technique and a high-order sliding mode control approach. The proposed method has no feed-forward factors and no singular points where the controller inputs become infinite values. Moreover, we designed the controller for the simplest high-order chained system and confirmed the superior performance of the controlled system by computer simulation.
• Lyapunov Functions for Homogeneous Differential Inclusions

  NAKAMURA Hisakazu, YAMASHITA Yuh, NISHITANI Hirokazu

  計測自動制御学会論文集 計測自動制御学会 39 (4) 365 - 374 0453-4654 2003 [Not refereed][Not invited]
  
• Observer Based I/O-linearizing Control of High Index DAE Systems

  2003 American Control Conference Proceedings 3537 - 3541 2003 [Not refereed][Not invited]
  
• Support systems for knowledge inheritance from video images of plant operations

  O Orapimpan, T Kurooka, Y Yamashita, H Nishitani

  PROCESS SYSTEMS ENGINEERING 2003, PTS A AND B 15 1466 - 1471 1570-7946 2003 [Not refereed][Not invited]
   

  It is difficult to extract tacit knowledge in the workplace. In this paper, we apply video annotation to externalize the technologies and skills in plant operations. We developed two prototype systems. The first is an interactive support system using multimedia, which offers functions for collecting know-how and know-why in on-site plant operations, and for presenting this information as learning materials. The second is a system for evaluating emergency training results and extracting the common problems and lesson points. This system is useful for sequential data analysis related to human behavior.
• Observer design for nonlinear systems described by differential-algebraic equations

  Y Yamashita, N Kidane, H Nishitani

  PROCESS SYSTEMS ENGINEERING 2003, PTS A AND B 15 1100 - 1105 1570-7946 2003 [Not refereed][Not invited]
   

  We propose an observer design method for a differential-algebraic equation (DAE) systems with index one. In the observer, the algebraic equation constraint is fulfilled asymptotically. The error of the constraint converges to zero in finite time by means of functions that do not satisfy the local Lipschitz condition. The dynamics part of the observer is designed via the linear matrix inequality (LMI) technique. The observer is globally asymptotically stable under certain assumptions. Since the algebraic equations include input variable, the observer requires the derivative of input to plant. The derivative of the input is calculated from the controller states directly or estimated by the exact differentiator of Levant.
• Modeling and simulation of human errors in plant operations

  YH Jin, T Kurooka, Y Yamashita, H Nishitani

  PROCESS SYSTEMS ENGINEERING 2003, PTS A AND B 15 1280 - 1285 1570-7946 2003 [Not refereed][Not invited]
   

  We have developed a cognitive information processing model that incorporates the states of mind and body in order to simulate a plant operator's behavior under abnormal situations. This model enables simulation of human errors under various conditions. As an illustrative example, oversights in using two graphic panels designed for monitoring a boiler plant were examined. The results coincided qualitatively with observations of actual plant operations. This operator model can be used to analyze various types of human errors from the viewpoint of cognitive information processing and to study how to cope with different situations.
• 心理状態を考慮したオペレータモデルの開発

  金 銀花, 黒岡 武俊, 山下 裕

  日本プラント・ヒュ-マンファクタ-学会誌 日本プラント・ヒュ-マンファクタ-学会 7 (2) 86 - 96 1342-4459 2003/01 [Not refereed][Not invited]
  
• Discontinuous control of nonholonomic systems using nondifferentiable Lyapunov functions

  H Nakamura, Y Yamashita, H Nishitani, H Yamamoto

  SICE 2003 ANNUAL CONFERENCE, VOLS 1-3 1415 - 1418 2003 [Refereed][Not invited]
   

  This research focuses on the problem of discontinuous controller design by using a non-differentiable Lyapunov function. We propose a new concept for a solution of the discontinuous system. We design a discontinuous controller for a nonholonomic system by using a non-differentiable Lyapunov function and analyze the stability of the controlled system by using the proposed solution. Moreover, we confirm the performance of the controlled system by computer simulation.
• Stabilizability analysis and controller design for a nonlinear system with an input constraint

  N Kidane, H Nakamura, Y Yamashita, H Nishitani

  SICE 2003 ANNUAL CONFERENCE, VOLS 1-3 1419 - 1422 2003 [Refereed][Not invited]
   

  Researches on nonlinear systems with input constraints have been based on control Lyapunov functions that assure global stability, and the stabilizable region has not been investigated. In this paper, we investigate the stabilizability and the stabilizable region and design a controller that stabilizes the system. Then we show a simulation to demonstrate the usefulness of the controller.
• A Cognitive Information Processing Model for Analysis of Plant Operator Errors

  Yinhua Jin, Taketoshi Kurooka, Yuh Yamashita, Hirokazu Nishitani

  Proceedings of International Symposium on Design, Operation and Control of Chemical Processes 313 - 318 2002/12 [Refereed][Not invited]
  
• Compensation for transmission delay and data loss in remote control systems

  Yuh Yamashita, Hirokazu Nishitani

  Proceedings of International Symposium on Design, Operation and Control of Chemical Processes 141 - 146 2002/12 [Refereed][Not invited]
  
• Support System for Emergency Training in Plant Operations

  Opat Orapimpan, Taketoshi Kurooka, Yuh Yamashita, Hirokazu Nishitani

  Proceedings of International Symposium on Design, Operation and Control of Chemical Processes 345 - 350 2002/12 [Refereed][Not invited]
  
• Thinking State Monitoring with Plural Physiological Signals

  Taketoshi Kurooka, Masato Ando, Yuh Yamashita, Hirokazu Nishitani

  E International Conference on Systems, Man, and Cybernetics (CD-ROM) Paper ID: WP1N4  2002/10 [Refereed][Not invited]
  
• Real-time Optimization Method for Nonlinear Receding-Horizon Control

  IMAFUKU Kei, YAMASHITA Yuh, NISHITANI Hirokazu

  JRSJ The Robotics Society of Japan 20 (7) 759 - 770 0289-1824 2002/10 [Refereed][Not invited]
   

  An optimal control problem for nonlinear systems is useful because various control objectives can be included in the cost function such as rapid stabilization and input cost minimization. However, there exist input restrictions of actuators and state constraints that arise from the movable region of the system in the real system. Therefore, the optimal control problem should be solved to satisfy these restrictions. In this paper, we propose a new method to realize nonlinear receding-horizon control under input restrictions and state constraints. First, a receding horizon control problem is formulated. Next, a new real-time optimization method is proposed. Then, the method is applied to solve a receding-horizon control problem of a wheeled vehicle. The effectiveness of the proposed method is shown through simulations and experimental results.
• Stabilization of Nonholonomic Systems using Homogeneous Finite-time Control Technique

  Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nisitani

  15th World Congress of the IFAC 2437 - 2445 2002/07 [Refereed][Not invited]
  
• シミュレータトレーニング収録ビデオからの知識の創出

  Orapimpan Opat, 黒岡 武俊, 山下 裕

  日本プラント・ヒュ-マンファクタ-学会誌 日本プラント・ヒュ-マンファクタ-学会 7 (1) 10 - 19 1342-4459 2002/07 [Not refereed][Not invited]
  
• Tracking Control of Nonlinear Systems with No Relative Degree

  YAMASHITA Yuh, ONISHI Norio, NISHITANI Hirokazu

  Transactions of the Society of Instrument and Control Engineers 計測自動制御学会 38 (1) 18 - 25 0453-4654 2002/01/31 [Not refereed][Not invited]
   

  In this paper, we propose a new method of exact tracking control for multi-input multi-output nonlinear systems in which the relative degree for an output is not well defined at the origin. First, the system is transformed into a singularly perturbed system using a time-scale transformation and coordinate transformations. A composite control law is adopted to attain exact tracking control for the singularly perturbed system. However, it is difficult to solve simultaneous partial differential equations for the composite control law. We obtain an approximate solution of the PDEs via the ε-correction method. The proposed tracking control law is applied to the ball and plate system, which is a typical example having no relative degree at the origin.
• Output regulation through singularities via state-feedback

  Y Yamashita

  NONLINEAR CONTROL SYSTEMS 2001, VOLS 1-3 633 - 638 0962-9505 2002 [Refereed][Not invited]
   

  In this paper, the problem of global output regulation using state-feedback is solved for nonlinear systems with no relative degree. We introduce an invariant manifold on which tracking error tends to zero, and through which we derive a coordinate transformation of state. The variable-gain feedback on the new coordinate attains global output regulation through singularities. Copyright (C) 2001 IFAC.
• 状態フィードバックを用いた非線形非最小位相系に対する大域的出力レギュレーション

  大西 規雄, 山下 裕, 西谷 紘一

  システム制御情報学会論文誌 15 (1) 336 - 343 2002/01 [Refereed][Not invited]
  
• I/O-Linearizing controller and observer for Nonlinear DAE systems with high index

  N Kidane, Y Yamashita, H Nishitani

  SICE 2002: PROCEEDINGS OF THE 41ST SICE ANNUAL CONFERENCE, VOLS 1-5 1966 - 1969 2002 [Refereed][Not invited]
   

  We consider I/O-linearization problems for differential algebraic equation (DAE) systems with high index using dynamic output feedback. First, a way to transform a DAE system to an explicit ordinary differential equation system is shown. Second, a design method is presented to achieve I/O-linearization by a static feedback law. Lastly, an observer is proposed to stabilize globally the controled system.
• Smooth Lyapunov functions for homogeneous differential inclusions

  H Nakamura, Y Yamashita, H Nishitani

  SICE 2002: PROCEEDINGS OF THE 41ST SICE ANNUAL CONFERENCE, VOLS 1-5 1974 - 1979 2002 [Refereed][Not invited]
   

  This paper provides a construction method of a smooth homogeneous Lyapunov function associated with a discontinuous homogeneous system, which is locally asymptotically stable. First, we analyze two similar converse Lyapunov theorems for differential inclusions and unify them into a simple theorem. Next, we propose a new definition of homogeneous differential inclusion. Then, we construct a smooth homogeneous Lyapunov function associated with the homogeneous differential inclusion. Lastly, we show that the order of homogeneity of a homogeneous system indicates the speed of convergence.
• Compensation for transmission delay in remote-control system under measurement noise

  Y Sawamura, Y Yamashita, H Nishitani

  SICE 2002: PROCEEDINGS OF THE 41ST SICE ANNUAL CONFERENCE, VOLS 1-5 219 - 222 2002 [Refereed][Not invited]
   

  In digital tele-communication, the delay time of the transmission isn't fixed. One solution is to design a new digital controller which is composed of an analog controller and two digital compensators. However, this system is weak to measurement noise. We develop a new digital controller that can cope with the problems of measurement noise by applying the H-infinity control method.
• Global asymptotic stabilization of nonminimum phase nonlinear systems via extended backstepping

  N Onishi, Y Yamashita, H Nishitani

  SICE 2002: PROCEEDINGS OF THE 41ST SICE ANNUAL CONFERENCE, VOLS 1-5 2249 - 2254 2002 [Refereed][Not invited]
   

  In this paper, we address the problem of global asymptotic stabilization for a single-input single-output non-linear system that may not be minimum phase. To solve this problem, we introduce a set of invariant manifolds which have hierarchical structure. We transform the plant repeatedly by using this set of invariant manifolds. Under the linear growth condition and some additional assumptions, global asymptotic stabilization is achieved by applying a variable-gain state feedback law to the obtained system.
• Discontinuous finite-time control of multi-generator nonholonomic systems

  H Nakamura, Y Yamashita, H Nishitani

  SICE 2002: PROCEEDINGS OF THE 41ST SICE ANNUAL CONFERENCE, VOLS 1-5 1980 - 1983 2002 [Refereed][Not invited]
   

  This paper focuses on the problem of finite-time stabilization of multi-generator nonholonomic systems using discontinuous feedback. We propose time-invariant discontinuous controllers based on the invariant-manifolds approach for stabilizing these systems. In the proposed method, the system is finite-time stable and the number of switching times of control is limited.
• Computation Method for Optimal Control Problem with Terminal Constraints using Genetic Algorithm

  Yuh Yamashita, Masasuke Shima

  Transactions of the Society of Instrument and Control Engineers E-1 274 - 280 2001/12 [Refereed][Not invited]
  
• Real-time monitoring of a plant operator's thinking state

  T Kurooka, M Yamakawa, Y Yamashita, H Nishitani

  JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 34 (11) 1387 - 1395 0021-9592 2001/11 [Refereed][Not invited]
   

  We have been studying the use of multiple channel electroencephalogram (EEG) data to infer a human's thinking state. As a result, we have confirmed off-line thinking state estimation to be effective, in experimental studies on simulator training during malfunctions and mathematics problem solving. In this research, we developed a real-time system that monitors a human's thinking state on the basis of off-line results. First, an artificial neural network (ANN) model and a linear regression model were compared to determine which was more appropriate for real-time use. The ANN model was adopted because of its ease of handling and higher accuracy in thinking state estimation. Then, a prototype real-time thinking state monitoring (RTSM) system with the ANN model was developed and its effectiveness was evaluated experimentally via mathematics problem solving. Finally, we discuss a conception of plant operations with RTSM.
• Acquiring and Representing Know-how and Know-why in On-site Plant Operations

  Opat Orapimpan, Taketoshi Kurooka, Yuh Yamashita, Hirokazu Nishitani

  Proceedings of HCI International 2001 239 - 241 2001/08 [Refereed][Not invited]
  
• The Development of a Real-time Thinking State Monitoring System for Plant Operators

  Hirokazu Nishitani, Yuh Yamashita, Taketoshi Kurooka

  Usability Evaluation and Interface Design: Cognitive Engineering, Intelligent Agents and Virtual Reality 1 1445 - 1449 2001/08 [Refereed][Not invited]
  
• Condition Monitoring of a Heterogeneous Azeotropic Distillation Column Using Self-Organizing Maps

  Taketoshi Kurooka, Sadaharu Morishita, Yuh Yamashita, Hirokazu Nishitani

  6th IFAC Symposium on Dynamics and Control of Process Systems 585 - 590 2001/06 [Refereed][Not invited]
  
• Development of a Learning System of Know-How and Know-Why in On-site Plant Operations

  Opat Orapimpan, Kouichi Sakata, Taketoshi Kurooka, Yuh Yamashita, Hirokazu Nishitani

  日本プラント・ヒューマンファクター学会誌 日本プラント・ヒュ-マンファクタ-学会 6 (1) 33 - 44 1342-4459 2001/04 [Refereed][Not invited]
  
• A real-time thinking state monitoring system for plant operation

  T Kurooka, M Yamakawa, Y Yamashita, H Nishitani

  HUMAN-COMPUTER INTERACTION - INTERACT'01 609 - 616 2001 [Refereed][Not invited]
   

  We have developed a real-time thinking state monitoring (RTSM) system for plant operation. First, the conception of plant operation with RTSM is proposed. Second, an estimation method of an operator's thinking state is reviewed. A nonlinear neural-network (NN) model and a linear regression model are applied as the estimation model. Third, the estimation method is experimentally evaluated by off-line analysis. It is confirmed that the NN model has some advantages. Finally, a prototype RTSM system with the NN model is developed and experimentally evaluated. The effectiveness is shown using mathematics problem solving.
• Global output regulation of nonminimum phase nonlinear systems

  N Onishi, Y Yamashita, H Nishitani

  PROCEEDINGS OF THE 40TH IEEE CONFERENCE ON DECISION AND CONTROL, VOLS 1-5 79 - 84 0191-2216 2001 [Refereed][Not invited]
   

  We address the problem of global output regulation for a single-input single-output nonlinear system that may not be minimum phase. Some invariant manifolds are introduced to transform the system into a form that is easier to handle. It is shown that a variable-gain feedback law can carry out the global output regulation of the system under some additional assumptions.
• I/O-Linearizing Controller with Observer for Nonlinear Systems Described by Differential-Algebraic Equations

  YAMASHITA Yuh, NISHITANI Hirokazu, SHIMA Masasuke

  計測自動制御学会論文集 計測自動制御学会 36 (12) 1101 - 1107 0453-4654 2000/12/31 [Not refereed][Not invited]
  
• Numerical Methods for Viscosity Solutions of an Optimal Control Problem and an Obstacle Avoidance Problem for a Wheeled Vehicle

  IMAFUKU Kei, YAMASHITA Yuh, NISHITANI Hirokazu

  Transactions of the Institute of Systems, Control and Information Engineers 一般社団法人 システム制御情報学会 44 (10) 458 - 469 1342-5668 2000/10 [Refereed][Not invited]
   

  To construct an optimal regulator for a wheeled vehicle, we need a viscosity solution of the Hamilton-Jacobi partial differential equation (HJ-PDE). In this paper, we propose a new method to have the viscosity solution of the HJ-PDE more quickly by applying a new searching method which uses a sequence of random inputs. This method reduces the number of searching points and makes calculation time faster than the previous method. Next, we propose a method to have the viscosity solution for obstacle avoidance. From the theoretical result of optimal control with state constraints, we can get the viscosity solution which avoids obstacles optimally. Then we make sure that an optimal solution can be obtained analytically by the finite difference numerical approximation of the HJ-PDE. This new result gives us an optimal solution without searching. Finally, the effectiveness of control results calculated from proposed methods are confirmed through simulations.
• 視線分析を用いたプラントオペレータの挙動の分析

  山本 純平, 黒岡 武俊, 山下 裕

  日本プラント・ヒューマンファクター学会誌 日本プラント・ヒューマンファクター学会 5 (2) 88 - 98 1342-4459 2000/10 [Not refereed][Not invited]
  
• 高速探索手法によるCSTRの自励振動反応を利用した収率のオンライン最適化

  今福 啓, 山下 裕, 西谷 紘一

  化学工学論文集 26 (5) 683 - 686 0386-216X 2000/09 [Refereed][Not invited]
  
• Design and verification of the SFC program for sequential Control

  K Fujino, K Imafuku, Y Yamashita, H Nishitani

  COMPUTERS & CHEMICAL ENGINEERING 24 (2-7) 303 - 308 0098-1354 2000/07 [Refereed][Not invited]
   

  A programmable controller (PC) programming technique using SFC (sequential function chart) has been adopted in sequential control system design because SFC can graphically represent the sequence how of control logic. However, when we design an SFC program, we must verify the program with the design specifications. For this purpose, we can use scenario simulation and exhaustive simulation. In this paper, we propose to model both the controlled object and the SFC program by a Petri net for verification by both types of simulations. (C) 2000 Elsevier Science Ltd. All rights reserved.
• Mind state estimation for operator support

  T Kurooka, Y Yamashita, H Nishitani

  COMPUTERS & CHEMICAL ENGINEERING 24 (2-7) 551 - 556 0098-1354 2000/07 [Refereed][Not invited]
   

  We have developed a method to estimate a plant operator's thinking state during abnormal situations. The operator's thinking state is estimated from EEG data. First, three basic modes were defined according to the typical thinking slate of a plant operator at the time of a malfunction. Second, experiments were performed to evoke the basic modes. Third, a nonlinear model was developed to estimate the thinking state of a plant operator. Finally, the estimation method was applied to a subject who operated a boiler plant simulator under abnormal circumstances. It was verified that the method gives useful information for estimating the plant operator's thinking state. (C) 2000 Elsevier Science Ltd. All rights reserved.
• Dynamic simulation and nonlinear control system design of a heterogeneous azeotropic distillation column

  T Kurooka, Y Yamashita, H Nishitani, Y Hashimoto, M Yoshida, M Numata

  COMPUTERS & CHEMICAL ENGINEERING 24 (2-7) 887 - 892 0098-1354 2000/07 [Refereed][Not invited]
   

  A nonlinear control system was considered for a heterogeneous azeotropic distillation column that separates a three component mixture of water, n-butyl-acetate, and acetic acid. This system shows such complex dynamic behavior that it is difficult to operate it and to design its controller. In this study, we developed a dynamic simulator to understand and characteristics of the process. After considering the system's behavior by using the simulator, a control system was developed with exact input-output linearization. The control performance was examined when a step change happened in the feed composition and the feed flow rate. Compared with a multiloop control system, the proposed control system can quickly settle down at the setpoints with small fluctuations. (C) 2000 Elsevier Science Ltd. All rights reserved.
• Multivariable control of a distillation column by exact input-output linearization

  T. Kurooka, Y. Yamashita, H. Nishitani

  Journal of Chemical Engineering of Japan 33 (3) 406 - 412 0021-9592 2000/06 

  Exact input-output linearization was applied to multivariable control of a distillation column. A four-input four-output system was transformed to four SISO systems by input-output linearization based on a simplified framework of the column. A control system was designed for the linearized four SISO systems, accounting for the effect of model mismatch. The performances of the control system were examined with simulation of a methanol-water distillation column. The control system by input-output linearization exhibited better performance than the conventional multi-loop control systems. These properties were evident under large scaled disturbances. Original is an abstract.
• Mulitivariable Control of a Distillation Column by Exact Input-Output Linearization

  Taketoshi Kurooka, Yuh Yamashita, Hirokazu Nishitani

  Kagaku Kogaku Ronbunshu 26 (3) 406 - 412 1349-9203 2000 [Refereed][Not invited]
   

  Exact input-output linearization, which is one method of nonlinear control, was applied to multivariable control of a distillation column. First, a four-input four-output system was transformed to four SISO systems by input-output linearization based on a simplified model of the distillation column. For this purpose, an appropriate set of outputs must be selected. Second, a control system was designed for the linearized four SISO systems, considering the influence of model mismatch. Finally, the performances of the control system were evaluated with simulation of a methanol-water distillation column. The simulation model was much more rigorous than the simplified one used for controller design. From the various viewpoints, such as the speed of response, recovery of the materials, and energy efficiency, the control system by input-output linearization showed better performance than the conventional multiloop control system. These characteristics were clearly noticed under large scaled disturbances. input-output linearization, distillation column, multivariable control, nonlinear control, process control. © 2000, The Society of Chemical Engineers, Japan. All rights reserved.
• Global output regulation through singularities

  Y Yamashita, A Isidori

  PROCEEDINGS OF THE 39TH IEEE CONFERENCE ON DECISION AND CONTROL, VOLS 1-5 1295 - 1300 0743-1546 2000 [Refereed][Not invited]
   

  In this paper, global output regulation problem using state-feedback for nonlinear systems with no relative degree is concidered. We introduce an invariant manifold on which tracking error tends to zero, and through which we derive a coordinate transformation of state. By means of the forwarding design method, it is shown that a simple feedback on the new coordinate attains the global output regulation through singularities.
• Exact Input-Output Linearization Control of Heterogeneous Azeotropic Distillation Column

  Taketoshi Kurooka, Yuh Yamashita, Hirokazu Nishitani

  1999 AIChE Annual Meeting (CD-ROM) Paper ID: 228i  1999/11 [Refereed][Not invited]
  
• Mind State Estimation in Logical Thinking Jobs

  Taketoshi Kurooka, Yuh Yamashita, Hirokazu Nishitani

  IEEE International Conference on Systems, Man, and Cybernetics 407 - 412 1999/10 [Refereed][Not invited]
  
• 複数仕様を満たす制御系設計法の吸収冷凍機への応用

  大形 明弘, 山下 裕, 西谷 紘一

  化学工学論文集 25 (5) 721 - 727 0386-216X 1999/09 [Refereed][Not invited]
  
• Controller Design with Multiple Specifications for an Absorption Heat Pump System

  Akihiko Ohgata, Yuh Yamashita, Hirokazu Nishitani

  The 8th Congress of Asian Pacific Confederation of Chemical Engineering 599 - 602 1999/08 [Refereed][Not invited]
  
• Measurement of Operator's Thinking State using EEGs

  Taketoshi Kurooka, Yuh Yamashita, Hirokazu Nishitani

  The 8th Congress of Asian Pacific Confederation of Chemical Engineering 1001 - 1004 1999/08 [Refereed][Not invited]
  
• Control of a Wheeled Vehicle Using the Viscosity Solution of the Hamilton-Jacobi Partial Differential Equation

  Kei Imafuku, Yuh Yamashita, Hirokazu Nishitani

  Journal of the Robotics Society of Japan The Robotics Society of Japan 17 (5) 689 - 695 0289-1824 1999/07 [Refereed][Not invited]
   

  To construct an optimal regulator for nonlinear systems, we need to solve a Hamilton-Jacobi partial differential equation (HJ-PDE) . However, if the system has nonholonomic constraints, the HJ-PDE has a nonsmooth solution because of the nonsmoothness of the optimal cost function. In such a case, the viscosity solution, a nonsmooth weak solution of the HJ-PDE, is obtained.
  In this paper, we deal with a wheeled vehicle, which is a nonholonomic system, and propose a numerical method to achieve a viscosity solution of the HJ-PDE using the dynamic programming principle (DPP) . The DPP can be applied to acquire a nonsmooth solution of the HJ-PDE. We also construct an optimal control law using derivatives of the viscosity solution of the HJ-PDE. The effectiveness of the proposed method is shown through simulations.
• Estimation of Plant Operator's Thinking State using EEGs

  Taketoshi Kurooka, Yuh Yamashita, Hirokazu Nishitani

  The 15th World Congress of International Measurement Confederation (CD-ROM) Paper ID: 18.2.3 - 412 1999/06 [Refereed][Not invited]
  
• An Algorithm to Find a Static State Feedback Gain Matrix to Satisfy Multiple Specifications

  OGATA Akihiro, YAMASHITA Yuh, NISHITANI Hirokazu

  The Transactions of the Institute of Electrical Engineers of Japan. C 電気学会 119 (5) 615 - 623 0385-4221 1999/05 [Not refereed][Not invited]
  
• Application of mind state estimation to plant operators

  T Kurooka, M Kisa, Y Yamashita, H Nishitani

  ANALYSIS, DESIGN AND EVALUATION OF MAN-MACHINE SYSTEMS 1998 479 - 484 1999 [Refereed][Not invited]
   

  We developed a linear regression model with Electroencephalograms (EEGs) to estimate the mind state of a plant operator. First, we defined three modes according to the typical thinking state of plant operators. The classification was validated by preparatory experiments with card games, mathematical problems, and pussies. The estimation method was applied to a plant operator who operates a boiler plant simulator under abnormal situations. As a result, the method provided the plant operator's mind state, which is liable to be overlooked by analysing with a simple interview and observation. Copyright (C) 1998 IFAC.
• On the Nonstandard Nonlinear H_∞ Control Problem

  IMAFUKU Kei, YAMASHITA Yuh, SHINBA Takahiro, SHIMA Masasuke, NISHITANI Hirokazu

  Transactions of the Society of Instrument and Control Engineers 計測自動制御学会 35 (1) 59 - 65 0453-4654 1999/01 [Not refereed][Not invited]
   

  Sufficient conditions of the nonstandard nonlinear H_∞ control problem are provided. This problem needs not to satisfy the rank condition of the direct-through matrices from the controlled input to the regulated output and from the disturbance to the measured output. First, we present a feedback law via state feedback. Next, a feedback law via output feedback and an observer gain are given. It is shown by extending the result of the linear system to the nonlinear system.
• 脳波を用いたプラントオペレ-タの思考状態推定

  黒岡 武俊, 木佐 昌文, 山下 裕

  日本プラント・ヒュ-マンファクタ-学会誌 日本プラント・ヒュ-マンファクタ-学会 3 (2) 100 - 109 1342-4459 1998/10 [Not refereed][Not invited]
  
• A New Method of Solving the Hamilton-Jacobi Partial Differential Equation

  YAMASHITA Yuh, SHIMA Masasuke

  Transactions of the Society of Instrument and Control Engineers 計測自動制御学会 34 (6) 571 - 576 0453-4654 1998/06/30 [Not refereed][Not invited]
   

  A New method of solving the Hamilton-Jacobi partial differential equation is proposed. Hamilton-Jacobi partial differential equations are often used for solving nonlinear-H^∞-control problems or nonlinear-optimal-control problems. Some trajectories of the Hamiltonian system which is generated from the Hamiltonian function related to the Hamilton-Jacobi equation give a stable manifold of the system approximately, so they produce the derivative of the storage function. From their trajectories, the solution of the Hamilton-Jacobi equation is approximated with Bezier interpolation. The initial states of the trajectories are given by the linear system which approximates the dynamics on the stable manifold.
• Control of Wheeled vehicle using dynamic programming principle

  Kei Imafuku, Yuh Yamashita, Hirokazu Nishitani

  Mathematical Theory of networks and Systems 1027 - 1030 1998 [Refereed][Not invited]
  
• Controller Design of Absorption Heat Pump System via LMI

  Akihiro Ohgata, Yuh Yamashita, Hirokazu Nishitani

  Kagaku Kogaku Ronbunshu 24 (2) 291 - 298 1349-9203 1998 [Refereed][Not invited]
   

  An absorption heat pump system is a complex nonlinear system. The system dynamics varies considerably depending on the load. The local linearization technique is not suitable for such a system, because a linearized model approximates the original nonlinear system only in the neighborhood of the point where linearization is done. In this paper, the dynamics of an absorption heat pump system is modeled as a linear time-varying system, of which the system matrix is within a specified polytope at any time. Once a plant is modeled as a polytope system, a controller design problem can be reduced to a convex programming problem which can be solved easily. Numerical simulations illustrate that this procedure is practical and effective to design a load following controller for the absorption heat pump system. © 1998, The Society of Chemical Engineers, Japan. All rights reserved.
• Tracking control for unlinearizable nonlinear systems

  Y Yamashita, T Bono, M Shima, H Nishitani

  NONLINEAR CONTROL SYSTEMS DESIGN 1998, VOLS 1& 2 195 - 200 1998 [Refereed][Not invited]
   

  In this paper, we consider a tracking problem for nonlinear systems of which input-output behaviors cannot be linearized. Such a system is converted to a singularly perturbed control system using a time-scale transformation and coordinate transformations under some assumptions The exact-tracking control for the singularly perturbed control system is accomplished by a composite control law. The exact-tracking control law is approximated by truncating higher-order terms with respect to epsilon. The proposed method is applied to a ball and beam example. Copyright (C) 1998 IFAC.
• Numerical computational method using genetic algorithm for the optimal control problem with terminal constraints and free parameters

  Y Yamashita, M Shima

  NONLINEAR ANALYSIS-THEORY METHODS & APPLICATIONS 30 (4) 2285 - 2290 0362-546X 1997/12 [Refereed][Not invited]
  
• Invariance condition of general nonlinear control system with integral type output

  M Shima, Y Yamashita

  NONLINEAR ANALYSIS-THEORY METHODS & APPLICATIONS 30 (4) 2279 - 2284 0362-546X 1997/12 [Refereed][Not invited]
  
• プラント運転を行うオペレータモデルの開発

  北島 禎二, 中山 慶彦, 黒岡 武俊, 山下 裕, 西谷 紘一

  本プラント・ヒューマンファクター学会誌 日本プラント・ヒュ-マンファクタ-学会 2 (2) 106 - 115 1342-4459 1997/10 [Refereed][Not invited]
  
• プラントオペレーションにおけるヒューマンモデリング

  中山 慶彦, 北島 禎二, 山下 裕, 西谷 紘一

  化学工学 化学工学会 61 (8) 612 - 613 0375-9253 1997/08/05 [Not refereed][Not invited]
  
• On the Nonstandard Nonlinear H∞ Control Problem

  Yuh Yamashita, Takahiro Shinba, Masasuke Shima, Hirokazu Nishitani

  Proc. of the 2nd Asian Control Conference 579 - 582 1997/07 [Refereed][Not invited]
  
• Computation Method for Optimal Control Problem with Terminal Constraints Using Genetic Algorithm

  YAMASHITA Yuh, SHIMA Masasuke

  Transactions of the Society of Instrument and Control Engineers 計測自動制御学会 33 (3) 189 - 194 0453-4654 1997/03/31 [Not refereed][Not invited]
   

  In this paper, a new numerical computation method using genetic algorithm for an optimal control problem with terminal constraints and singular arcs is proposed. The input functions are parameterized using spline interpolation, which has devices that can represent discontinuous input functions. In order to treat the terminal constraints properly, Lagrange multipliers that are contained in genetic information of chromosomes are introduced. On the singular arcs, coefficients of inputs in Hamiltonian vanish, so the coefficients on the arcs are included in the extended performance index. The weight constants of the extended performance index are changed adaptively at every generation of the genetic algorithm. A simple example is solved using this method, which verifies the efficiency of genetic algorithm in the computation of the optimal control.
• Robust control of an absorption heat pump system

  A Ohgata, Y Yamashita, H Nishitani

  COMPUTERS & CHEMICAL ENGINEERING 21 (Supplement 1) S131 - S136 0098-1354 1997 [Refereed][Not invited]
   

  An absorption heat pump system is a complex nonlinear system. We proposed a practical procedure of controller design based on the idea of global linearization. Numerical simulation runs have illustrated this procedure is practical and effective for the complex nonlinear system.
• Tracking control using self-organizing neural network

  Y Yamashita, Y Ikuno, M Shima

  PROCEEDINGS OF THE 35TH IEEE CONFERENCE ON DECISION AND CONTROL, VOLS 1-4 3804 - 3809 0191-2216 1996 [Refereed][Not invited]
   

  An identification method and a tracking controller for nonlinear discrete-time systems using ''neural-gas network'' are proposed. Neural-gas network is a kind of self-organizing networks, and was developed by Martinet and Schulten[1]. The system is identified by estimating a hypersurface in the space of input and output sequences using neural-gas network. The metric of the space of synapse weight is modified to increase efficiency of learning. The hypersurface is expressed with a method by means of rational Bezier surface or direct interpolation. An inverse model of the system is derived from the surface, which is applied to tracking control problem.
• Adaptive Multi-Step Learning Control for Time-Varying Linear Systems

  YAMASHITA Yuh, MIYAMOTO Junichi, SHIMA Masasuke

  Transactions of the Institute of Systems, Control and Information Engineers 一般社団法人 システム制御情報学会 7 (4) 134 - 141 1342-5668 1994/04 [Refereed][Not invited]
   

  In this paper, the adaptive multi-step learning control for continuous-time linear system is studied. Input function u_k+1 (t) is calculated from the triplets (u_k, e_k, e_k) and (u_k-1, e_k-1, e_k-1) where e_k is tracking error of k-th trial. The weighting coefficients of the triplets are determined adaptively. The convergence of the control law is proved by means of evaluation of the norm of tracking error. Moreover, the learning control is applied to the tracking problem of two-link robot manipulator.
• CMACによる非線形離散時間系のモデル追従制御

  山下 裕, 佐藤 友彦, 島 公脩

  Transactions of the Institute of Systems, Control and Information Engineers 一般社団法人 システム制御情報学会 4 (6) 245 - 251 1342-5668 1991/06 [Refereed][Not invited]
   

  This paper discusses a design method of "neural controller" which achieves the model following control for a SISO nonlinear discrete-time system. If the system dynamics is completely known, the model following control law can be derived as a nonlinear function of input-output sequence via the nonlinear control theory. Under reasonable assumptions, a neural network CMAC-Cerebellar Model Arithmetic Computer-is able to learn both the uncertain nonlinear dynamics of the system and the nonlinear function which yields the model following controller. Moreover, in order to improve the accuracy and the speed of learning, the data presented to the CMAC are transformed by the difference method or the correlation method. It is shown by computer simulations that our method works well and the correlation method is better than the difference method.
• Conditions of Invariance and Decoupling for Continuous-time or Discrete-time General Nonlinear Systems

  YAMASHITA Yuh, SHIMA Masasuke

  Transactions of the Institute of Systems, Control and Information Engineers 一般社団法人 システム制御情報学会 3 (9) 277 - 286 1342-5668 1990/09 [Refereed][Not invited]
   

  In our previous paper 4) -12), we have studied "Theory of Invariance" for nonlinear continuous-time systems with their inputs appearing linearly. The aim of this paper is to derive necessary and sufficient conditions that inputs never effect outputs (so called conditions of "Invariance") for nonlinear discrete-time and continuous-time systems without the assumption of linearity in inputs. Applying these conditions to the decoupling problem, we obtained necessary and sufficient conditions which yield decoupling control laws for both the continuous-time systems and the discrete-time systems. The conditions of decoupling given by van der Schaft 13) and Grizzle 14) via geometric approach are different in forms from ours. But, it seems difficult to derive control laws from their conditions because the integration of partial deferential equations is needed there.
• 一般的な非線形系における入出力線形化

  山下 裕, 島 公脩

  計測自動制御学会論文集 計測自動制御学会 26 (9) p1009 - 1014 0453-4654 1990/09 [Not refereed][Not invited]
  
• 4元数による表現を用いた飛行体の大角度姿勢制御

  細川 民樹, 山下 裕, 島 公脩

  計測自動制御学会論文集 計測自動制御学会 26 (4) p467 - 473 0453-4654 1990/04 [Not refereed][Not invited]
  
• Theory of Invariance and its Applications-X. Block Decoupling

  YAMASHITA Yuh, SHIMA Masasuke

  Transactions of the Institute of Systems, Control and Information Engineers 一般社団法人 システム制御情報学会 1 (3) 108 - 116 1342-5668 1988/03 [Refereed][Not invited]
   

  In this paper, we study the block decoupling problem of nonlinear systems with C^ω-Structures : x=f (x) +G (x) u, y=h (x). Inputs and outputs are divided into N blocks, respectively. First, we propose a new algorithm by which we can determine the maximal locally controlled invariant distribution contained in Ker dh. This algorithm is an extension of nonlinear structure algorithm extensively used in the input-output linearlization, and can be applied to systems which is not input-output linearlizable. Moreover, it has an advantage in that we need not integrate the distribution.
  Application of this algorithm to I-th output block yields a vector valued function z_I(x).Then, the block decoupling problem is solvable if and only if each row of D(G)z_I(x) is zero vector or is linearly independent of rows of other D(G)z_J(x)(J=1, …, N; I≠J). The state feedback control law which accomplishes the block decoupling is derived from z_I(x).
• Invarianceの理論とその応用-9-多入力多出力非線形系の出力可制御性

  山下 裕, 島 公脩

  システムと制御 日本自動制御協会 31 (6) p450 - 456 0374-4507 1987/06 [Not refereed][Not invited]
  

MISC

• What has not yet been Realized in Nonlinear Control?

  Yuh Yamashita  計測と制御  60-  (1)  339  -344  2021/05  [Not refereed][Invited]
  
• State Estimation for Distributed Control Systems on Networks with Communication Delays

  足立 亮介, 山下 裕, 小林 孝一  システム制御情報学会研究発表講演会講演論文集  61-  6p  2017/05/23
• Asynchronous Control of Networked Control Systems with Decentralized Event-Triggering Conditions

  中島 共平, 小林 孝一, 山下 裕  電子情報通信学会技術研究報告 = IEICE technical report : 信学技報  116-  (433)  31  -34  2017/01/27
• Value Assessment of Model Predictive-Based Demand Response

  Miyazaki Kodai, Kobayashi Koichi, Azuma Shun-ichi, Yamaguchi Nobuyuki, Yuh Yamashita  Proceedings of the Japan Joint Automatic Control Conference  60-  344  -347  2017
• Simultaneous Optimization of Control and Routing for Sensor and Actuator Networks (ITS)

  佐藤 大, 小林 孝一, 山下 裕  電子情報通信学会技術研究報告 = IEICE technical report : 信学技報  116-  (338)  89  -93  2016/12/01
• Decentralized Suboptimal Event-triggered Control for Discrete-time Linear Systems

  中島 共平, 小林 孝一, 山下 裕  電子情報通信学会技術研究報告 = IEICE technical report : 信学技報  115-  (442)  13  -16  2016/01/29
• Backstepping for a set-valued upper control law

  鈴木 大基, 山下 裕, 椿野 大輔  システム制御情報学会研究発表講演会講演論文集  59-  4p  2015/05/20
• Collision Avoidance in LQR-based Formation Control

  楠木 孝, 椿野 大輔, 山下 裕  システム制御情報学会研究発表講演会講演論文集  58-  5p  2014/05/21
• Algebras containing Laplacian matrices of some basic graphs

  庄司 恵, 椿野 大輔, 山下 裕  システム制御情報学会研究発表講演会講演論文集  58-  5p  2014/05/21
• Vehicle Formation Control based on LQ Optimal Regulator Preserving Triangular Structure

  楠木 孝, 椿野 大輔, 山下 裕  システム制御情報学会研究発表講演会講演論文集  57-  5p  2013/05/15
• Numerical Computation of Families of Dissipative Boundaries for Two-Dimensional Gradient-Like Morse-Smale Dynamical Systems

  IZUE Yukishige, ENOMOTO Ryuji, YAMASHITA Yuh  The Transactions of the Institute of Electronics, Information and Communication Engineers. A  95-  (3)  261  -267  2012/03/01  

  本研究では,大城コンパクトアトラクタをもつような任意に与えられた二次元こう配的Morse-Smale力学系のリヤプノフ関数を求めることを最終目的としている.我々は,これまでに位相幾何学的な手法を利用して正則散逸境界を数値的に算定するアルゴリズムを示した.本論文では,二次元こう配的Morse-Smale力学系の特異散逸境界を含む散逸境界族の数値データを求めるためのアルゴリズムを提案し,その有効性を数値例を用いて示す.
• 支部の活動

  渡辺 桂吾, 山下 裕, 曽根 秀昭, 寺嶋 一彦, 大薮 多可志, 黒江 康明, 谷口 隆雄, 岡 宏一, 石飛 光章  計測と制御 = Journal of the Society of Instrument and Control Engineers  50-  (8)  570  -577  2011/08/10  [Not refereed][Not invited]
  
• Distributed Coordinative Control for Unknown Work Load

  YAMASHITA Yuh  IEICE technical report  108-  (276)  65  -70  2008/10/30  

  In this paper, we consider a covering control problem for mobile robots. We propose a control method that cancels the effects of an unknown distributed disturbance and makes the mobile robots move to equalize the canceling loads of all robots. In the model of this paper, the distributed disturbance dynamically increases "work loads" to be treated by mobile robots, while in the model of Cortes et al., 2004, the work loads are given a priori by a known function. The control law of each mobile robot is derived by the passivity theory, and its feedback function consists of spatially local information. Simulation of the covering problem shows the effectiveness and some problems of the proposed method.
• Solutions of Systems with Discontinuous Control and a Global Asymptotic Stabilization Problem

  TSUZUKI Takayuki, YAMASHITA Yuh  Systems, control and information  52-  (3)  84  -89  2008/03/15
• Markov過程の量子化を用いた確率的Lyapunov関数の構築—Stochastic Lyapunov function design using quantization of Markov process—非線形問題

  西村 悠樹, 山下 裕  電子情報通信学会技術研究報告 = IEICE technical report : 信学技報  107-  (399)  47  -52  2007/12/19
• Robust analysis of a discontinuous control system

  TSUZUKI Takayuki, YAMASHITA Yuh  IEICE technical report  107-  (399)  43  -46  2007/12/12  

  For nonlinear control systems defined on general manifolds, it is known that there there exist neither continuous global asymptotic stabilizer and control Lyapunov function. A general control Lyapunov function is propsoed to solve the stabilization problem. This paper shows that if a general control Lyapunov function exists for a nonlinear system, there exists a discontinuous global asymptotic stabilizer. Moreover, a robustness with respect to a disturbance is analyzed.
• Output Regulation of Nonlinear Control Systems

  YAMASHITA Yuh  Journal of The Society of Instrument and Control Engineers  42-  (10)  821  -826  2003/10/10  [Not refereed][Not invited]
  
• 非線形系の出力レギュレーション問題 (特集 非線形性に挑む--システム制御理論の最前線)

  山下 裕  計測と制御  42-  (10)  821  -826  2003/10  [Not refereed][Not invited]
  
• On the Compensation for Transmission Delay and Data Loss in Remote Control Systems

  YAMASHITA Yuh  Journal of The Society of Instrument and Control Engineers  41-  (7)  513  -518  2002/07/10  [Not refereed][Not invited]
  
• Estimation of Logical Thinking State Using EEGs

  YAMAKAWA Masashi, KUROOKA Taketoshi, YAMASHITA Yuh, NISHITANI Hirokazu  Human Interface  2-  (3)  7  -12  2000/06/16
• 非線形制御--日本学術振興会143委員会WS19報告 (特集 新時代を担う計装・情報化テクノロジー --その可能性を探る--計装・情報化テクノロジーの活用視点と役割)

  山下 裕  計装  43-  (1)  25  -29  2000/01  [Not refereed][Not invited]
  
• Applications of the genetic algorithm for control problems

  Shima M., Yamashita Y.  物性研究  66-  (4)  659  -662  1996
• Output tracking control for nonlinear singularly perturbed systems

  Yamashita Y, Kishi N, Shima M  Bulletin of the Faculty of Engineering, Hokkaido University  167-  (0)  157  -167  1994/01  [Not refereed][Not invited]
  
• Feedback Design for General Nonlinear Systems

  YAMASHITA Yuh  計測と制御 = Journal of the Society of Instrument and Control Engineers  31-  (8)  859  -864  1992/08/10  [Not refereed][Not invited]
  
• ニュ-ラルネットワ-クによる学習・適応制御 (ニュ-ラルネット<特集>)

  山下 裕, 島 公脩, 石動 善久  計測と制御  30-  (4)  p302  -308  1991/04  [Not refereed][Not invited]
  
• 非線形制御系の設計アルゴリズムとCAD (非線形システム特集号)

  石動 善久, 山下 裕, 島 公脩  システム・制御・情報  33-  (9)  p445  -453  1989/09  [Not refereed][Not invited]
  

Books etc

• 非線形システム制御論

  島 公脩, 石動 善久, 山下 裕, 渡邉 昭義, 川村 武, 横道 政裕 
  コロナ社 1997 (ISBN: 4339031674)
• 「非線形システム論」

  計測自動制御学会 1993

Research Projects

• Energy saving control using discontinuous or non-positive definite input cost

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research

  Date (from‐to) : 2019/04 -2022/03 

  Author : Yamashita Yuh

   

  Considering an energy-saving optimal control problem when the target value of the state does not coincide with the stationary point of minimum energy consumption, we formulated the problem by slightly modifying the input cost function from the natural energy consumption and constructed a nonlinear optimal regulator that guarantees asymptotic stability. In addition, when actuators require standby power, the operation of deactivating inefficient actuators according to the value of the state values contributes to energy conservation in redundant input systems. We proposed an optimal controller design method that performs such an operation. We also proposed a control method that includes suspending the communication of sensor values according to output values.
• 制御リアプノフ関数を用いた入力分配制御

  日本学術振興会：科学研究費補助金(基盤研究(B))

  Date (from‐to) : 2016/04 -2019/03 

  Author : 山下 裕
• Development of topological control theory for decision making

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research

  Date (from‐to) : 2015/04 -2018/03 

  Author : Nakamura Hisakazu

   

  This research aims to design a framework of combining decision and control from the view point of topology. The major achievements are as follows. Development of a control strategy that dynamically identifies the desired state by the minimum projection method, development of the local minimum connection method for static control Lyapunov function design, and development of a human safety assist control strategy by using control barrier functions. By the preceding achievements, this research elucidates that a control Lyapunov function and a control barrier function are effective for the combination of decision and control.
• Radon測度上の動的システムの研究と都市構造遷移モデルへの応用

  日本学術振興会：科学研究費補助金(挑戦的萌芽研究)

  Date (from‐to) : 2014/04 -2017/03 

  Author : 山下 裕
• Nonlinear control theory based on generalized semiconcave functions

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research

  Date (from‐to) : 2011/04 -2014/03 

  Author : NAKAMURA Hisakazu, YAMASHITA Yuh, ITO Hiroshi, ENOMOTO Ryuji, FUKUI Yoshiro

   

  We proposed feed back controller design method by using disassembled differential. Moreover, we confirmed that our proposed method is available for input constrained control systems. We proved that Jurdjevic-Quinn type controllers permit local Caratheodory solutions of closed-loop systems. We analyzed desingularization phenomena on our proposed minimum projection method, and proposed a singular point assignment method for nonsmooth control Lyapunov function design. Moreover, we proposed static control Lyapunov function and static controller design methods based on dynamic extention and the minimum projection method.
• Stability Analysis of Dynamical Systems on Topological Spaces

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research

  Date (from‐to) : 2011 -2013 

  Author : NAKAMURA Nami, YAMASHITA Yuh, NAKAMURA Hisakazu

   

  We have defined Lagrange stability and input-to-state stability for nonlinear systems on manifolds. Furthermore, we have presented necessary and sufficient conditions for stability by using continuous positive definite proper functions. We have designed an ISS-control Lyapunov function and an input-to-state stabilizing controller for an obstacle avoidance problem of a mobile robot. Then, we have confirmed the effectiveness of the proposed controller by computer simulation. We have proposed a sample input-to-state stabilizing controller for general nonlinear systems on manifolds.
• Study on the nonlinear control using transformation to state-jump system

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research

  Date (from‐to) : 2010 -2012 

  Author : YAMASHITA Yuh, NAKAMURA Hisakazu, NISHIDA Gou, NISHIMURA Yuki, TSUZUKI Takayuki

   

  his study proposes a framework of control system design methodologies bywhich the state space of a dynamical controlled object is extended by adding new continuous or discretecoordinates and a desired closed-loop is designed on the augmented space allowing state-jumps on thenew coordinates. Furthermore, methods of the degeneracy of the extended space for obtaining adiscontinuous static feedback law or a control law with discrete states are given. By introducingstate-jumps, we can construct a controller mathematically even for decision-making problems of thedynamical systems.
• Establishment of nonlinear control theory taking into account global structure of manifold

  Ministry of Education, Culture, Sports, Science and Technology：Grants-in-Aid for Scientific Research(基盤研究(C))

  Date (from‐to) : 2007 -2009 

  Author : Yuh YAMASHITA, Hisakazu NAKAMURA, Gou NISHIDA, Yuki NISHIMURA

   

  This study presents a general framework for controlling nonlinear systems on general manifolds including non-Euclidean spaces which precedent control theories cannot handle. Global attitude control of satellites, obstacle avoidance of vehicles, and control of acrobots are examples of our problem. This framework provides design procedures generating control laws automatically with discontinuity, logic, or randomness, of which properties are necessary to stabilize such systems on non-Euclidean spaces.
• Development of Plant Operator Model Incorporating Mental and Physical States

  Ministry of Education, Culture, Sports, Science and Technology：Grants-in-Aid for Scientific Research(基盤研究(B))

  Date (from‐to) : 2002 -2005 

  Author : Hirokazu NISHITANI, 今福 啓, 黒岡 武俊, 山下 裕, 小坂 洋明, 中村 文一

   

  This project aimed at understanding plant operator's behavior under abnormal situations through dynamic simulation by using some cognitive information processing model incorporating the mental and physical states and proposing some method to create appropriate countermeasures. We obtained the following three main results.1.We installed a new plant operator model that is a cognitive information processing model incorporating the mental and physical states on a PC and connected to an industrial boiler plant simulator for operator training. This operator model was used in analyzing the various...
• Control system design using non-smooth feedback

  Ministry of Education, Culture, Sports, Science and Technology：Grants-in-Aid for Scientific Research(基盤研究(C))

  Date (from‐to) : 2003 -2004 

  Author : Yuh YAMASHITA, 中村 文一

   

  1.We obtained a simple expression of the converse Lyapunov theorem for discontinuous systems. Also, the converse Lyapunov theorem for discontinuous homogeneous systems with dilations was developed, which shows that each discontinuous homogeneous strongly stable system with dilation has a homogeneous Lyapunov function. It was shown that the degree of homogeneity indicates the speed of the convergence, i.e. a homogeneous strongly stable system with a negative degree of homogeneity has a finite-time convergence property. The proof of the finite time convergence of high-order sliding mode contr...
• Study on the construction of control theory by the notion of invariance and the development of its introductory course

  Ministry of Education, Culture, Sports, Science and Technology：Grants-in-Aid for Scientific Research(基盤研究(C))

  Date (from‐to) : 2001 -2003 

  Author : Masasuke SHIMA, 横道 政裕, 川村 武, 石動 善久, 山下 裕, 榎本 隆二

   

  Firstly, the role of invariance in the control theory is studied [1]Invariance with respect to the variation of parameters : Using Frazer-Duncan theorem and monotonicity conditions, we derived a necessary and sufficient condition for the stability of linear systems without regard to the variation of interval parameters, and presented a monotonization method for the system which is not monotone. [2]Feedback design considering structures of Lie algebra : Feedback stabilization and improvement of tracking properties ties are studied for the under actuated mechanical systems such as axi-symmetr...
• Control Design for Nonlinear System Described by Differential-Algebraic Equations

  Ministry of Education, Culture, Sports, Science and Technology：Grants-in-Aid for Scientific Research(基盤研究(C))

  Date (from‐to) : 2000 -2002 

  Author : Yuh YAMASHITA, 黒岡 武俊

   

  In this research, we study controller design of nonlinear systems described by differential-algebraic equations (DAE). In nonlinear cases, it is hard to convert the system to ordinary differential equations (ODE) without redundancy, because nonlinear algebraic equations cannot be solved analytically in general.First, for nonlinear DAE systems with index one, a design method of exact I/O-linearizing control and observer is proposed, where the global-stability condition of the observer is also obtained. The estimated state variables in the observer converge to an invariant manifold determined...
• Estimation of a Plant Operator's Mental State and its Application to Operator Support

  Ministry of Education, Culture, Sports, Science and Technology：Grants-in-Aid for Scientific Research(基盤研究(B))

  Date (from‐to) : 2000 -2001 

  Author : Hirokazu NISHITANI, 黒岡 武俊, 山下 裕

   

  We have been studying the use of multiple channel elecroencephalogram (EEG) data to infer a human's thinking state. As a result, we have confirmed off-line thinking state estimation to be effective, in experimental studies on simulator training during malfunctions and mathematical problem solving. In this research, we reconsidered the mathematical model for thinking state estimation and concluded that an artificial neural network (ANN) model is more appropriate for real-time use than the linear regression model.We developed a prototype real-time thinking state monitoring system with the ANN...
• Modeling and Simulation of Plant-Wide Control Systems

  Ministry of Education, Culture, Sports, Science and Technology：Grants-in-Aid for Scientific Research(基盤研究(C))

  Date (from‐to) : 1997 -1998 

  Author : Hirokazu NISHITANI, 北島 禎二, 黒岡 武俊, 山下 裕

   

  In this study, plant-wide control is regarded as the total activities generated by feedback control for continuous processes, sequential control for discrete events and supervisory control for process malfunction and equipment failure. The integration of these control elements enables safe and efficient plant control or operation. However, there is no theory for design of the plant-wide control system. Dynamic simulation is the only way to handle such a large and complicated system. In the first year, we investigated modeling and simulation techniques to evaluate system performances of a pl...
• Robust Design of Nonlinear Control Systems

  Ministry of Education, Culture, Sports, Science and Technology：Grants-in-Aid for Scientific Research(一般研究(B))

  Date (from‐to) : 1994 -1995 

  Author : Masasuke SHIMA, 川村 武, 山下 裕, 石動 善久

   

  In this year, we have obtained the following results.1.The nonlinear non-standard H^* control problem is studied. In this research, two cases are concerned with : (a) the case in which the direct-through term from the input to the output does not have full-rank, and (b) the case in which the direct-through term from the disturbance to the measurement output does not have full-rank. In these cases, the square compliment cannot be carried out with the usual method, and thus the Hamilton-Jacobi-Issacs partial differential inequality is not well-defined. To resolve this difficulty, the term inc...
• ハミルトン・ヤコビ偏微分方程式の数値解法

  文部科学省：科学研究費補助金(奨励研究(A))

  Date (from‐to) : 1994 -1994 

  Author : 山下 裕

   

  本研究では、以下の成果を得た。・正準方程式の安定多様体がハミルトン・ヤコビ偏微分方程式の解であることを利用し、時間軸を逆にとることによって、常微分方程式の数値解法に帰着させた。・上記の常微分方程式を数値的に解くにあたって、その初期点を与えるアルゴリズムを開発した。具体的には、初期サンプル点を一様に分布させ、安定多様体上の線形近似式を用いて原点近傍までシミュレートし、さらに安定多様体の1次近似を用いて2n次元の初期点を得る方法を開発した。原点近傍までの所要時間をもとに・得られた解曲線をBezier補間式で最小2乗近似し、状態量χの関数として表現した。その関数を用いて制御器を作ることが可能となった。・上記の手法を基に、購入したワークステーション上に、目的の解を高精度に得る解法パッケージを開発した。・本方法の特長の1つは、得られた解曲線の存在範囲によって、得られた解の有効な定義域が推定できることである。これは、原点でのTaylor展開による従来の方法ではできなかったことである。
• 遺伝的アルゴリズムによる制御

  文部科学省：科学研究費補助金(奨励研究(A))

  Date (from‐to) : 1993 -1993 

  Author : 山下 裕

   

  本研究に関する研究実績は以下の通りである。1.遺伝的アルゴリズムを最適制御問題、特に最適特異制御問題の数値解法に応用した。最適制御問題の数値解法として幾つかの方法が知られているが、最適特異制御問題を解くことのできる方法は非常に少ない。本研究では、遺伝子上に幾つかの時間の点における入力の大きさをコーディングし、3次スプライン曲線でそれらをつないで、制御入力とした。最適制御においては、入力の関数が不連続となることが多いので、遺伝子上には不連続となる場所に関する情報も加えた。本研究では、槽式流通反応系の最適コスト問題に対し、これらの方法を適用したが、bang-bang制御の区間と最適特異軌道の区間が明確に現れ、良好な結果を得た。これらの成果に関して、現在、投稿準備中である。2.遺伝的アルゴリズムをファジイ制御に応用し、シミュレーションを繰り返すことによりファジイルールを自動生成する研究をおこなった。ファジィ制御の前件部の取りうるすべての組み合わせに対して、その後件部を遺伝子上にコーディングし、オフラインでシミュレーションを繰り返し遺伝的アルゴリズムを用いることで、ファジイルールを自動生成した。本研究では、この方法を車両の障害物回避問題に適用した。試行結果の評価値のみの情報で、ランダムなファジイルールが次第に、障害物を回避し目標に到達するように進化した。これらの成果に関しては、さらに...
• A Study of the System Theory via Controlled Path Integral

  Ministry of Education, Culture, Sports, Science and Technology：Grants-in-Aid for Scientific Research(一般研究(C))

  Date (from‐to) : 1991 -1992 

  Author : Masasuke SHIMA, 山下 裕, 石動 善久

   

  In this research project, we studied the possibility of system theory based on the controlled path integrals. The dynamical behavior of the system is described by a vector field X=X_0+X_1u^1+...+X_mu^m defined on a manifold M as a state space. u=(u^1,...,u^m) are control inputs to the system. The control u(t) given on [t_0,t_1] deter mines the state trajectory p(t). Assuming that a differential form omega is given and integrating omega(X) along the trajectory, we obtain the controlled path integral associated with omega and X. Outputs of a system, Lyapunov function and the performance index...
• 非線形制御理論
• Nonlinear control theory