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Last Updated :2024/10/07

研究者情報

マスター

アカウント（マスター）

  • 氏名

    山下　裕(ヤマシタ　ユウ), ヤマシタ　ユウ

所属（マスター）

  • 情報科学研究院　システム情報科学部門　システム創成学分野

所属（マスター）

  • 情報科学研究院　システム情報科学部門　システム創成学分野

独自項目

syllabus

  • 2021, システム制御理論特論, Systems Control Theory, 修士課程, 情報科学研究科, 非線形動的システム, ハイブリッド動的システム, 非線形制御, 受動性アプローチ, 厳密な線形化, 混合論理動的システムモデル, モデル予測制御
  • 2021, システム制御理論特論, Systems Control Theory, 修士課程, 情報科学院, 非線形動的システム, ハイブリッド動的システム, 非線形制御, 受動性アプローチ, 厳密な線形化, 混合論理動的システムモデル, モデル予測制御
  • 2021, システム創成学特論, Frontiers of System Creation Technologies, 修士課程, 情報科学研究科, H∞制御，人間センシング，ディジタル幾何処理，サイバーフィールド
  • 2021, システム創成学特論, Frontiers of System Creation Technologies, 修士課程, 情報科学院, H∞制御，人間センシング，ディジタル幾何処理，サイバーフィールド
  • 2021, システム制御理論特論, Systems Control Theory, 博士後期課程, 情報科学研究科, 非線形動的システム, ハイブリッド動的システム, 非線形制御, 受動性アプローチ, 厳密な線形化, 混合論理動的システムモデル, モデル予測制御
  • 2021, システム制御理論特論, Systems Control Theory, 博士後期課程, 情報科学院, 非線形動的システム, ハイブリッド動的システム, 非線形制御, 受動性アプローチ, 厳密な線形化, 混合論理動的システムモデル, モデル予測制御
  • 2021, システム創成学特論, Frontiers of System Creation Technologies, 博士後期課程, 情報科学研究科, H∞制御，人間センシング，ディジタル幾何処理，サイバーフィールド
  • 2021, システム創成学特論, Frontiers of System Creation Technologies, 博士後期課程, 情報科学院, H∞制御，人間センシング，ディジタル幾何処理，サイバーフィールド
  • 2021, 情報エレクトロニクス概論, Introduction to Electronics and Information Engineering, 学士課程, 工学部, 情報理論, 計算機ハードウエア, 電子デバイス, 生体情報, 生命科学, 電子回路, 通信, メディア, ネットワーク, 電気回路, 制御工学
  • 2021, 英語演習, English Seminar, 学士課程, 全学教育, 先端テクノロジー，ロボット，OS，通信ネットワーク，火星探査，電動飛行機
  • 2021, 情報学 Ⅰ, Introduction to Informatics I, 学士課程, 全学教育, 情報活用，情報社会，情報科学，プログラミング，データサイエンス
  • 2021, 線形システム論, Linear System Theory, 学士課程, 工学部, ダイナミカルシステム, 線形システム, 可制御性, 可観測性, 周波数特性, 安定性
  • 2021, メカトロニクス基礎, Fundamental Mechatronics, 学士課程, 工学部, 材料力学, 振動論, 解析力学
  • 2021, ディジタル制御, Digital Control, 学士課程, 工学部, 線形離散時間システム, システム表現, 離散化, 安定性, 最適レギュレータ, オブザーバ, カルマンフィルタ

researchmap

プロフィール情報

学位

  • 博士(工学)（北海道大学）

プロフィール情報

  • 姓

    山下, 山下

  • 名

    裕, 裕

  • ID各種

    200901089891188357

対象リソース

業績リスト

研究キーワード

  • 非線形制御理論   知能機械学・機械システム   制御工学   

研究分野

  • 情報通信 / ロボティクス、知能機械システム
  • 情報通信 / 機械力学、メカトロニクス
  • ものづくり技術（機械・電気電子・化学工学） / 制御、システム工学

経歴

  • 2019年04月 - 現在 北海道大学 大学院情報科学研究院システム情報科学部門 教授

委員歴

  • 2021年03月 - 現在   計測自動制御学会   論文集委員会 (和文・制御部門editor)
  • 2015年 - 現在   IFAC   TC2.3 member
  • 2013年02月 - 2015年02月   計測自動制御学会   理事
  • 2011年 - 2012年   システム制御情報学会   理事
  • 2007年 - 2009年   計測自動制御学会   北海道支部長   計測自動制御学会
  • 2006年 - 2008年   計測自動制御学会   「多様な非線形ダイナミクスを生かした次世代制御調査研究会」主査   計測自動制御学会
  • 2005年 - 2008年   システム制御情報学会   理事   システム制御情報学会
  • 2004年 - 2007年   計測自動制御学会   北海道支部幹事   計測自動制御学会

受賞

  • 2018年06月 電子情報通信学会 第74回（平成29年度）論文賞
     Linear Quadratic Regulator with Decentralized Event-Triggering 
    受賞者: 中島 共平;小林 孝一;山下 裕

論文

  • Ikkei Komizu, Koichi Kobayashi, Yuh Yamashita
    Computation 12 10 196 - 196 2024年09月30日 
    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.
  • Fuma MOTOYAMA, Koichi KOBAYASHI, Yuh YAMASHITA
    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E107.A 5 793 - 798 2024年05月01日
  • Shota Nakayama, Koichi Kobayashi, Yuh Yamashita
    Advanced Robotics 38 9-10 603 - 609 2024年02月28日
  • Keita Terashima, Koichi Kobayashi, Yuh Yamashita
    Advanced Robotics 2024年02月14日
  • Ryo Matsuoka, Koichi Kobayashi, Yuh Yamashita
    Future Internet 2024年02月
  • Fuma Motoyama, Koichi Kobayashi, Yuh Yamashita
    IEEE Transactions on Control of Network Systems 2024年
  • Keita TERASHIMA, Koichi KOBAYASHI, Yuh YAMASHITA
    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E107-A 1 31 - 37 2024年01月 [査読有り]
  • Kyohei MURAKATA, Koichi KOBAYASHI, Yuh YAMASHITA
    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E107-A 1 25 - 30 2024年01月 [査読有り]
  • Finite-Time Control of Boolean Networks Using Binary Decision Diagrams
    Fuma Motoyama, Koichi Kobayashi, Yuh Yamashita
    Proc. SICE Annual Conference 2023 145 - 148 2023年09月 [査読有り]
  • Redesign of Control Lyapunov Functions of Nonlinear Systemswith Symmetry under Feedbacks
    Yuh Yamashita, Koichi Kobayashi
    Proc. SICE Annual Conference 2023 411 - 414 2023年09月 [査読有り]
  • Nakayama Shota, Kobayashi Koichi, Yamashita Yuh
    Proc. of the 2023 International Symposium on Nonlinear Theory and Its Application 467 - 470 2023年09月 [査読有り]
  • 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年07月 [査読有り]
  • 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年07月 [査読有り]
  • 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年07月 [査読有り]
  • Yuh Yamashita, Wataru Hashimoto, Koichi Kobayashi
    IFAC-PapersOnLine 56 2 8036 - 8041 2023年07月 [査読有り]
  • Michiaki Takizawa, Koichi Kobayashi, Yuh Yamashita
    Applied Mathematics and Computation 457 128211 - 128211 2023年07月 [査読有り]
  • 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年06月
  • 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年06月 [査読有り]
  • Fuma Motoyama, Koichi Kobayashi, Yuh Yamashita
    IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences E106-A 5 721 - 728 2023年05月 [査読有り]
  • Sho Obata, Koichi Kobayashi, Yuh Yamashita
    IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences E106-A 5 729 - 735 2023年05月 [査読有り]
  • Ryosuke Adachi, Yuh Yamashita, Koichi Kobayashi
    International Journal of Robust and Nonlinear Control 33 1 49 - 66 2023年01月10日 [査読有り]
     
    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.
  • Yuh Yamashita, Kiminori Sakano, Koichi Kobayashi
    International Journal of Robust and Nonlinear Control 33 1 35 - 48 2023年01月10日 [査読有り]
  • Sheng Hao, Yuh Yamashita, Koichi Kobayashi
    International Journal of Robust and Nonlinear Control 33 5 3247 - 3266 2023年01月06日 [査読有り][通常論文]
  • 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年01月 [査読有り]
  • 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年01月 [査読有り]
  • Koichi KITAMURA, Koichi KOBAYASHI, Yuh YAMASHITA
    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences 2023年 [査読有り]
  • Ayaka Tanaka, Koichi Kobayashi, Yuh Yamashita
    Advanced Robotics 37 1 1 - 10 2023年01月 [査読有り]
  • 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年12月 [査読有り]
  • Daiki OGAWA, Koichi KOBAYASHI, Yuh YAMASHITA
    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E105-A 11 1478 - 1485 2022年11月 [査読有り]
  • 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年10月 [査読有り]
  • 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年09月 [査読有り]
  • 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年07月 [査読有り]
  • Sho OBATA, Koichi KOBAYASHI, Yuh YAMASHITA
    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E105-A 6 1015 - 1019 2022年06月 [査読有り][通常論文]
  • Koichi KITAMURA, Koichi KOBAYASHI, Yuh YAMASHITA
    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E105-A 5 816 - 822 2022年05月 [査読有り][通常論文]
  • 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年01月 [査読有り][通常論文]
  • Sheng Hao, Yuh Yamashita, Koichi Kobayashi
    International Journal of Robust and Nonlinear Control 32 1 373 - 392 2022年01月 [査読有り][通常論文]
  • Yuh Yamashita, Ryosuke Matsukizono, Koichi Kobayashi
    Automatica 138 110032 - 110032 2021年11月 [査読有り][通常論文]
  • Ryosuke Adachi, Yuh Yamashita, Koichi Kobayashi
    IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences E104-A 11 1470 - 1476 2021年11月 [査読有り][通常論文]
  • Sho Obata, Koichi Kobayashi, Yuh Yamashita
    2021 IEEE 10th Global Conference on Consumer Electronics (GCCE) 472 - 473 2021年10月12日 [査読有り][通常論文]
  • 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年09月 [査読有り][通常論文]
  • 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年09月 [査読有り][通常論文]
  • Optimal Control Considering Standby Power of Actuators
    Kunitsugu, Yohei, Yamashita, Yuh, Kobayashi, Koichi
    Proc. of the SICE Annual Conference 2021 467 - 470 2021年09月 [査読有り][通常論文]
  • 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年09月 [査読有り][通常論文]
  • 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 2021年09月 [査読有り][通常論文]
  • Koichi Kitamura, Koichi Kobayashi, Yuh Yamashita
    IEEE International Symposium on Industrial Electronics 2021- 2021年06月20日 
    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.
  • Yuh Yamashita, Haruka Sumita, Ryosuke Adachi, Koichi Kobayashi
    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E104-A 3 613 - 621 2021年03月 [査読有り][通常論文]
     
    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.
  • Koichi Kobayashi, Kyohei Nakajima, Yuh Yamashita
    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E104-A 2 455 - 461 2021年02月 [査読有り][通常論文]
  • Daiki Ogawa, Koichi Kobayashi, Yuh Yamashita
    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E104-A 2 423 - 429 2021年02月 [査読有り][通常論文]
  • Sho Obata, Koichi Kobayashi, Yuh Yamashita
    Digest of Technical Papers - IEEE International Conference on Consumer Electronics 2021- 2021年01月10日 
    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.
  • Ryosuke Adachi, Yuh Yamashita, Koichi Kobayashi
    IFAC Journal of Systems and Control 14 100109 - 100109 2020年12月 [査読有り][通常論文]
  • Yuh Yamashita, Naoto Adachi, Ryo Nonaka, Koichi Kobayashi
    Systems & Control Letters 145 104776 - 104776 2020年11月 [査読有り][通常論文]
  • Daiki Ogawa, Koichi Kobayashi, Yuh Yamashita
    Proc. of the IEEE 9th Global Conference on Consumer Electronics 58 - 59 2020年10月 [査読有り][通常論文]
  • Shogo Shimamoto, Koichi Kobayashi, Yuh Yamashita
    Proc. of the IEEE 9th Global Conference on Consumer Electronics 60 - 61 2020年10月 [査読有り][通常論文]
  • Sheng Hao, Yuh Yamashita, Koichi Kobayashi
    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E103.A 9 1078 - 1085 2020年09月01日 [査読有り][通常論文]
  • 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年09月 [査読有り][通常論文]
  • 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年09月 [査読有り][通常論文]
  • 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年09月 [査読有り][通常論文]
  • 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年07月 [査読有り][通常論文]
  • 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年07月 [査読有り][通常論文]
  • On Minimum Time Control for Dynamical Transportation Using ADMM
    Ryosuke Adachi, Yuh Yamashita, Koichi Kobayashi
    Proc. of the 21st IFAC World Congress 2020年07月 [査読有り][通常論文]
  • Yuh Yamashita, Yuta Sakai, Koichi Kobayashi
    IFAC-PapersOnLine (Special issue of 21st IFAC World Congress) 53 2 6819 - 6824 2020年07月 [査読有り]
  • Sheng Hao, Yuh Yamashita, Koichi Kobayashi
    IFAC-PapersOnLine (Special issue of 21st IFAC World Congress) 53 2 5586 - 5591 2020年07月 [査読有り]
  • Ryosuke Adachi, Yuh Yamashita, Koichi Kobayashi
    IFAC-PapersOnLine (Special issue of 21st IFAC World Congress) 53 2 3330 - 3335 2020年07月 [査読有り]
  • 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年07月 [査読有り][通常論文]
  • 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年07月 [査読有り][通常論文]
  • ADACHI Ryosuke, YAMASHITA Yuh, KOBAYASHI Koichi
    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E103-A 2 469 - 477 一般社団法人 電子情報通信学会 2020年02月 [査読有り][通常論文]
     

    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.

  • Ryo Masuda, Koichi Kobayashi, Yuh Yamashita
    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E103-A 2 462 - 468 2020年02月 [査読有り][通常論文]
  • Shun Andoh, Koichi Kobayashi, Yuh Yamashita
    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E103.A 2 443 - 450 2020年02月01日 [査読有り][通常論文]
  • Shun Andoh, Koichi Kobayashi, Yuh Yamashita
    Proceedings of 2020 IEEE/SICE International Symposium on System Integration 1064 - 1069 2020年01月 [査読有り][通常論文]
  • Sheng Hao, Yuh Yamashita, Koichi Kobayashi
    Proceedings of 2020 IEEE/SICE International Symposium on System Integration 465 - 470 2020年01月 [査読有り][通常論文]
  • Katsuaki Umiji, Koichi Kobayashi, Yuh Yamashita
    Algorithms 12 12 268 (9 pages)  2019年12月 [査読有り][通常論文]
  • Ryo Masuda, Koichi Kobayashi, Yuh Yamashita
    Proc. of the 2019 IEEE International Conference on Systems, Man, and Cybernetics 3351 - 3356 2019年10月 [査読有り][通常論文]
  • 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年09月 [査読有り][通常論文]
  • Observer-Based Self-Triggered Pinning Control for Consensus of Multi-Agent Systems
    Shun Andoh, Koichi Kobayashi, Yuh Yamashita
    Proceedings of SICE Annual Conference 2019 1440 - 1443 2019年09月 [査読有り][通常論文]
  • On the Optimality of Distributed Observer Using Belief Propagation
    Ryosuke Adachi, Yuh Yamashita, Koichi Kobayashi
    Proceedings of SICE Annual Conference 2019 645 - 648 2019年09月 [査読有り][通常論文]
  • Akihisa Higashino, Yuh Yamashita, Koichi Kobayashi
    IFAC PapersOnline (Part of special issue: 11th IFAC Symposium on Nonlinear Control Systems) 52 16 747 - 752 2019年09月 [査読有り][通常論文]
  • Kodai Miyazaki, Koichi Kobayashi, Shun-Ichi Azuma, Nobuyuki Yamaguchi, Yuh Yamashita
    IEEE Transactions on Industrial Informatics 15 8 4809 - 4818 2019年08月 [査読有り][通常論文]
  • Koichi Kobayashi, Kyohei Nakajima, Yuh Yamashita
    Proceedings of the 2019 Asian Control Conference 1392 - 1397 2019年06月 [査読有り][通常論文]
  • Ryosuke Adachi, Yuh Yamashita, Koichi Kobayashi
    Proceedings of the 2019 Asian Control Conference 1386 - 1391 2019年06月 [査読有り][通常論文]
  • 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年06月 [査読有り][通常論文]
  • 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年06月 [査読有り][通常論文]
  • Daiki Ogawa, Koichi Kobayashi, Yuh Yamashita
    Proceedings of 2019 IEEE International Conference on Industrial Cyber Physical Systems 706 - 711 2019年05月 [査読有り][通常論文]
  • Ryosuke Adachi, Yuh Yamashita, Koichi Kobayashi
    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E102-A 5 712 - 720 2019年05月 [査読有り][通常論文]
  • Koichi Kobayashi, Mifuyu Kido, Yuh Yamashita
    IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences E102-A 2 372 - 378 2019年02月 [査読有り][通常論文]
  • Kenta Hoshino, Yuki Nishimura, Yuh Yamashita
    Systems & Control Letters 124 33 - 39 2019年02月 [査読有り][通常論文]
  • Wataru Hashimoto, Yuh Yamashita, Koichi Kobayashi
    IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences E102-A 1 227 - 234 2019年01月 [査読有り][通常論文]
  • Sheng Hao, Yuh Yamashita, Koichi Kobayashi
    Proc. of 2018 IEEE International Conference on Systems, Man, and Cybernetics 4383 - 4388 2018年10月 [査読有り][通常論文]
  • Koichi Kobayashi, Mifuyu Kido, Yuh Yamashita
    Proc. of 2018 IEEE International Conference on Systems, Man, and Cybernetics 2015 - 2020 2018年10月 [査読有り][通常論文]
  • 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年10月 [査読有り][通常論文]
  • Switching Controller Design for Quantized Event-Triggered Control
    Shumpei Yoshikawa, Koichi Kobayashi, Yuh Yamashita
    Proceedings of the SICE Annual Conference 2018 1797 - 1800 2018年09月 [査読有り][通常論文]
  • 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年09月 [査読有り][通常論文]
  • Yuh Yamashita, Kiminori Sakano, Koichi Kobayashi
    Proc. of the 23rd International Symposium on Mathematical Theory of Networks and Systems 435 - 440 2018年07月 [査読有り][通常論文]
  • 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年07月 [査読有り][通常論文]
  • 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年06月 [査読有り][通常論文]
  • Dai Satoh, Koichi Kobayashi, Yuh Yamashita
    International Journal of Control, Automation and Systems 16 3 953 - 960 2018年06月01日 [査読有り][通常論文]
     
    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.
  • Ryo MASUDA, Koichi KOBAYASHI, Yuh YAMASHITA
    SICE Journal of Control, Measurement, and System Integration 11 3 169 - 173 2018年05月 [査読有り][通常論文]
  • Ryosuke Adachi, Yuh Yamashita
    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E101A 4 678 - 684 2018年04月01日 [査読有り][通常論文]
     
    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.
  • Kazuya Nomura, Yuh Yamashita, Koichi Kobayashi
    Proc. of the SICE International Symposium on Control Systems 2018 220 - 225 2018年03月 [査読有り][通常論文]
  • Shumpei Yoshikawa, Koichi Kobayashi, Yuh Yamashita
    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E101A 2 322 - 327 2018年02月01日 [査読有り][通常論文]
     
    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年01月 [査読有り][通常論文]
  • Model Predictive-Based Demand Response in Energy Management Systems
    Kodai Miyazaki, Koichi Kobayashi, Shun-ichi Azuma, Nobuyuki Yamaguchi, Yuh Yamashita
    Proc. of the 23rd International Symposium on Artificial Life and Robotics 815 - 818 2018年01月 [査読有り][通常論文]
  • Kyohei Nakajima, Koichi Kobayashi, Yuh Yamashita
    IEEE Workshop on Signal Processing Advances in Wireless Communications, SPAWC 2017- 1 - 5 2017年12月19日 [査読有り][通常論文]
     
    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.
  • Wataru Hashimoto, Yuh Yamashita, Koichi Kobayashi
    Proceedings of the 2017 International Symposium on Nonlinear Theory and Its Applications 30 - 33 2017年12月 [査読有り][通常論文]
  • Kazuya Nomura, Yuh Yamashita, Koichi Kobayashi
    IFAC-PapersOnLine 50 1 14004 - 14009 2017年07月01日 [査読有り][通常論文]
     
    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.
  • Ryosuke Adachi, Yuh Yamashita, Koichi Kobayashi
    IFAC-PapersOnLine 50 1 2488 - 2493 2017年07月01日 [査読有り][通常論文]
     
    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.
  • Yuh Yamashita, Ryosuke Matsukizono, Koichi Kobayashi
    IFAC-PapersOnLine 50 1 1397 - 1402 2017年07月01日 [査読有り][通常論文]
     
    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年07月 [査読有り][通常論文]
  • Shin Kanazawa, Koichi Kobayashi, Yuh Yamashita
    SICE Journal of Control, Measurement, and System Integration 10 3 136 - 140 2017年05月 [査読有り][通常論文]
  • Mifuyu Kido, Koichi Kobayashi, Yuh Yamashita
    SICE Journal of Control, Measurement, and System Integration 10 3 253 - 258 2017年05月 [査読有り][通常論文]
  • Kyohei Nakajima, Koichi Kobayashi, Yuh Yamashita
    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES E100A 2 414 - 420 2017年02月 [査読有り][通常論文]
     
    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.
  • Dai Satoh, Koichi Kobayashi, Yuh Yamashita
    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES E100A 2 406 - 413 2017年02月 [査読有り][通常論文]
     
    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.
  • Shumpei Yoshikawa, Koichi Kobayashi, Yuh Yamashita
    2017 56TH ANNUAL CONFERENCE OF THE SOCIETY OF INSTRUMENT AND CONTROL ENGINEERS OF JAPAN (SICE) 313 - 316 2017年 [査読有り][通常論文]
     
    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.
  • Ryo Masuda, Koichi Kobayashi, Yuh Yamashita
    2017 56TH ANNUAL CONFERENCE OF THE SOCIETY OF INSTRUMENT AND CONTROL ENGINEERS OF JAPAN (SICE) 168 - 171 2017年 [査読有り][通常論文]
     
    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.
  • Dai Satoh, Koichi Kobayashi, Yuh Yamashita
    2017 56TH ANNUAL CONFERENCE OF THE SOCIETY OF INSTRUMENT AND CONTROL ENGINEERS OF JAPAN (SICE) 164 - 167 2017年 [査読有り][通常論文]
     
    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.
  • Yuh Yamashita
    2017 56TH ANNUAL CONFERENCE OF THE SOCIETY OF INSTRUMENT AND CONTROL ENGINEERS OF JAPAN (SICE) 209 - 213 2017年 [査読有り][通常論文]
     
    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年10月 [査読有り][通常論文]
  • Daiki Suzuki, Yuh Yamashita, Koichi Kobayashi
    Proceedings of the 2016 IEEE International Conference on Systems, Man, and Cybernetics 29 4 175 - 181 一般社団法人 システム制御情報学会 2016年10月 [査読有り][通常論文]
     
    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年09月 [査読有り][通常論文]
  • 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年09月 [査読有り][通常論文]
  • Kenta Hoshino, Yuki Nishimura, Yuh Yamashita, Daisuke Tsubakino
    IEEE TRANSACTIONS ON AUTOMATIC CONTROL 61 8 2318 - 2323 2016年08月 [査読有り][通常論文]
     
    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年07月11日 [査読有り][通常論文]
  • 鈴木大基, 山下裕
    システム制御情報学会論文誌 29 4 175 - 181 一般社団法人 システム制御情報学会 2016年04月 [査読有り][通常論文]
     
    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.
  • Kyohei Nakajima, Koichi Kobayashi, Yuh Yamashita
    PROCEEDINGS OF THE IECON 2016 - 42ND ANNUAL CONFERENCE OF THE IEEE INDUSTRIAL ELECTRONICS SOCIETY 5374 - 5379 2016年 [査読有り][通常論文]
     
    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.
  • W. Hashimoto, Y. Yamashita, R. Nonaka, K. Kobayashi
    IFAC PAPERSONLINE 49 18 235 - 240 2016年 [査読有り][通常論文]
     
    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.
  • Ryo Nonaka, Yuh Yamashita, Daisuke Tsubakino
    ADVANCED ROBOTICS 30 1 15 - 28 2016年01月 [査読有り][通常論文]
     
    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.
  • Takashi Aoki, Yuh Yamashita, Daisuke Tsubakino
    INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL 26 2 235 - 251 2016年01月 [査読有り][通常論文]
     
    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.
  • Yuh Yamashita
    IFAC-PapersOnLine 28 18 199 - 204 2015年11月01日 [査読有り][通常論文]
     
    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年07月 [査読無し][通常論文]
  • 久我創紀, 佐藤康之, 中村文一, 山下裕
    計測自動制御学会論文集 51 5 361 - 370 The Society of Instrument and Control Engineers 2015年05月 [査読有り][通常論文]
     
    "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.
  • Shunsuke KIMURA, Hisakazu NAKAMURA, Yuh YAMASHITA
    SICE Journal of Control, Measurement, and System Integration 8 2 122 - 130 The Society of Instrument and Control Engineers 2015年03月 [査読有り][通常論文]
     
    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.
  • Kenta Hoshino, Yuki Nishimura, Yuh Yamashita, Jun Yoneyama
    2015 IEEE CONFERENCE ON CONTROL AND APPLICATIONS (CCA 2015) 257 - 262 2015年 [査読有り][通常論文]
     
    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.
  • Ryosuke Adachi, Yuh Yamashita
    2015 IEEE CONFERENCE ON CONTROL AND APPLICATIONS (CCA 2015) 601 - 606 2015年 [査読有り][通常論文]
     
    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.
  • Ryo Nonaka, Yuh Yamashita, Daisuke Tsubakino
    IFAC-PapersOnLine 48 11 866 - 871 2015年 [査読有り][通常論文]
     
    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.
  • Daisuke Tsubakino, Yuh Yamashita
    2015 10TH ASIAN CONTROL CONFERENCE (ASCC) 2015年 [査読有り][通常論文]
     
    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.
  • Ryo Nonaka, Yuh Yamashita, Daisuke Tsubakino
    2015 AMERICAN CONTROL CONFERENCE (ACC) 5176 - 5181 2015年 [査読有り][通常論文]
     
    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.
  • Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani
    2009 European Control Conference, ECC 2009 2757 - 2762 2014年03月26日 
    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.
  • 青木 大輔, 椿野 大輔, 山下 裕
    自動制御連合講演会講演論文集 57 1412 - 1415 自動制御連合講演会 2014年 
    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．
  • 南 遼一朗, 椿野 大輔, 山下 裕
    自動制御連合講演会講演論文集 57 814 - 817 自動制御連合講演会 2014年 
    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．
  • Kenta Hoshino, Yuh Yamashita, Yuki Nishimura, Daisuke Tsubakino
    2014 IEEE 53RD ANNUAL CONFERENCE ON DECISION AND CONTROL (CDC) 3167 - 3172 2014年 [査読有り][通常論文]
     
    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.
  • Takashi Kusunoki, Daisuke Tsubakino, Yuh Yamashita
    2014 IEEE CONFERENCE ON CONTROL APPLICATIONS (CCA) 1072 - 1077 2014年 [査読有り][通常論文]
     
    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.
  • Daisuke Tsubakino, Miroslav Krstic, Yuh Yamashita
    Proc. 52nd IEEE Conf. Dec. & Cont. 3720 - 3725 2013年12月 [査読有り][通常論文]
  • Yuki Nishimura, Kanya Tanaka, Yuji Wakasa, Yuh Yamashita
    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES E96A 8 1695 - 1702 2013年08月 [査読有り][通常論文]
     
    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.
  • 椿野大輔, 野村和也, 山下裕
    システム制御情報学会論文誌 26 7 277 - 287 一般社団法人 システム制御情報学会 2013年07月 [査読有り][通常論文]
     
    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.
  • HOSHINO Kenta, YAMASHITA Yuh
    SICE J Control Meas Syst Integr 6 3 177 - 185 The Society of Instrument and Control Engineers 2013年05月 [査読有り][通常論文]
     
    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.
  • Momoko Yoshida, Yuh Yamashita
    2013 PROCEEDINGS OF SICE ANNUAL CONFERENCE (SICE) 1586 - 1591 2013年 [査読有り][通常論文]
     
    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.
  • Kenta Hoshino, Yuh Yamashita, Yuki Nishimura, Daisuke Tsubakino
    2013 IEEE 52ND ANNUAL CONFERENCE ON DECISION AND CONTROL (CDC) 1229 - 1234 2013年 [査読有り][通常論文]
     
    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.
  • Shunsuke Kimura, Hisakazu Nakamura, Yuh Yamashita
    IFAC Proceedings Volumes (IFAC-PapersOnline) 9 1 92 - 97 2013年 [査読有り][通常論文]
     
    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.
  • Kenta Hoshino, Yuki Nishimura, Yuh Yamashita, Daisuke Tsubakino
    2013 AMERICAN CONTROL CONFERENCE (ACC) 2013 Vol.8 6424 - 6429 2013年 [査読有り][通常論文]
     
    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.
  • Yûki Nishimura, Kanya Tanaka, Yuji Wakasa, Yuh Yamashita
    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E96-A 8 1695 - 1702 2013年 [査読有り][通常論文]
     
    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.
  • Kenta Hoshino, Yuh Yamashita, Yûki Nishimura, Daisuke Tsubakino
    Proceedings of the IEEE Conference on Decision and Control 1229 - 1234 2013年 [査読有り][通常論文]
     
    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.
  • Daisuke Tsubakino, Miroslav Krstic, Yuh Yamashita
    Proceedings of the IEEE Conference on Decision and Control 3720 - 3725 2013年 [査読有り][通常論文]
     
    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.
  • 草野 周, 山下 裕
    計測自動制御学会論文集 48 12 889 - 897 計測自動制御学会 ; [196-]- 2012年12月 [査読有り][通常論文]
  • 出江 幸重, 榎本 隆二, 山下 裕
    電子情報通信学会論文誌 J95-A 3 2011JAP1066  2012年03月 [査読有り][通常論文]
  • Takashi Aoki, Yuh Yamashita, Daisuke Tsubakino
    IFAC Proceedings Volumes (IFAC-PapersOnline) 45 19 42 - 47 2012年 [査読有り][通常論文]
     
    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.
  • Masahiro Yamada, Yuh Yamashita, Daisuke Tsubakino
    2012 IEEE INTERNATIONAL CONFERENCE ON CONTROL APPLICATIONS (CCA) 1590 - 1595 2012年 [査読有り][通常論文]
     
    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.
  • Ryo Nonaka, Yuh Yamashita, Daisuke Tsubakino
    2012 IEEE INTERNATIONAL CONFERENCE ON CONTROL APPLICATIONS (CCA) 1578 - 1583 2012年 [査読有り][通常論文]
     
    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.
  • Takayuki Tsuzuki, Taiki Yagi, Kazunobu Yoshida, Yuh Yamashita
    Proceedings of SICE Annual Conference 2011 390 - 394 2011年09月 [査読有り][通常論文]
  • Xuanxuan TENG, Yuh YAMASHITA
    SICE Journal of Control, Measurement, and System Integration 4 5 380 - 386 The Society of Instrument and Control Engineers 2011年09月 [査読有り][通常論文]
     
    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.
  • 西村 悠樹, 田中 幹也, 若佐 裕治, 山下 裕
    日本応用数理学会論文誌 21 3 197 - 209 一般社団法人 日本応用数理学会 2011年03月 [査読有り][通常論文]
     
    Pontryaginは最適制御問題を正準方程式として定式化したが,正準方程式は解析力学の枠組みで捉えられる.近年,最適制御系に正準量子化を施し量子力学系として定式化する手法が提案された.本稿では,無限時間最適レギュレータ問題の正準量子化手法で得られる特殊解が最適レギュレータの解に収束する条件について検討し,正準量子化手法が非線形最適レギュレータ問題の有用な近似解法を導く可能性について言及する.
  • Takahiro Yamazaki, Yuh Yamashita, Hisakazu Nakamura
    2011 50TH IEEE CONFERENCE ON DECISION AND CONTROL AND EUROPEAN CONTROL CONFERENCE (CDC-ECC) 7573 - 7578 2011年 [査読有り][通常論文]
     
    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.
  • Yuki Nishimura, Kanya Tanaka, Yuji Wakasa, Yuh Yamashita
    IFAC Proceedings Volumes (IFAC-PapersOnline) 18 1 8058 - 8063 2011年 [査読有り][通常論文]
     
    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.
  • Naoyoshi Ohkawa, Yuh Yamashita
    IFAC Proceedings Volumes (IFAC-PapersOnline) 18 1 3274 - 3279 2011年 [査読有り][通常論文]
     
    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.
  • Kenta Hoshino, Yuh Yamashita
    2011 19th Mediterranean Conference on Control and Automation, MED 2011 886 - 891 2011年 [査読有り][通常論文]
     
    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.
  • Xuanxuan Teng, Yuh Yamashita
    2011 19th Mediterranean Conference on Control and Automation, MED 2011 19 - 24 2011年 [査読有り][通常論文]
     
    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.
  • 都築 卓有規, 山下 裕
    計測自動制御学会論文集 46 10 598 - 606 The Society of Instrument and Control Engineers 2010年10月 [査読有り][通常論文]
     
    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.
  • Takayuki Tsuzuki, Yuh Yamashita
    Proceedings of SICE Annual Conference 2010 1559 - 1562 2010年08月 [査読有り][通常論文]
  • Yuh Yamashita
    Proceeding of IFAC Workshop on Periodic Control Systems 2010 75 - 80 2010年08月 [査読有り][通常論文]
  • 出江幸重, 榎本隆二, 山下裕
    電子情報通信学会論文誌 A J93-A 2 119 - 126 一般社団法人電子情報通信学会 2010年02月 [査読有り][通常論文]
     
    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.
  • Xuanxuan Teng, Yuh Yamashita
    2010 IEEE INTERNATIONAL CONFERENCE ON CONTROL APPLICATIONS 1773 - 1778 2010年 [査読有り][通常論文]
     
    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.
  • Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani
    SYSTEMS & CONTROL LETTERS 58 10-11 716 - 723 2009年10月 [査読有り][通常論文]
     
    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.
  • Nami Nakamura, Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani
    IEEE TRANSACTIONS ON AUTOMATIC CONTROL 54 9 2271 - 2275 2009年09月 [査読有り][通常論文]
     
    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.
  • Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani
    Proceedings of European Control Conference 2009 2757 - 2762 2009年08月 [査読有り][通常論文]
  • 西村悠樹, 山下裕
    システム制御情報学会論文誌 22 8 295 - 302 一般社団法人 システム制御情報学会 2009年08月 [査読有り][通常論文]
     
    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.
  • Yuki Nishimura, Yuh Yamashita, Kanya Tanaka, Yuji Wakasa
    Proceedings of 2009 ICCAS-SICE 691 - 694 2009年08月 [査読有り][通常論文]
  • 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 2009年 [査読有り][通常論文]
     
    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.
  • Nami Nakamura, Hisakazu Nakamura, Yuh Yamashita
    IEEE Transactions on Automatic Control 54 9 2271 - 2275 2009年 [査読有り][通常論文]
     
    In this paper, we propose an homogeneous stabilizing controller for input-affine homogeneous systems. Moreover, we provide an homogeneous inverse optimal controller.
  • Gou NISHIDA, Takayuki TSUZUKI, Hisakazu NAKAMURA, Yuh YAMASHITA
    SICE Journal of Control, Measurement, and System Integration 2 1 43 - 49 公益社団法人 計測自動制御学会 2009年01月 [査読有り][通常論文]
     
    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.
  • Yuki Nishimura, Kazuki Takehara, Yuh Yamashita, Kanya Tanaka, Yuji Wakasa
    Proceedings of the IEEE Conference on Decision and Control 7363 - 7368 2009年 [査読有り][通常論文]
     
    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.
  • Proceedings of 47th IEEE Conference on Decision and Control 3475 - 3480 2008年 [査読無し][通常論文]
  • NISHIDA G.
    Proceedings of 17th IFAC World Congress 6190 - 6195 2008年 [査読無し][通常論文]
  • Global asymptotic stabilization for a nonlinear system on a manifold via a dynamic compensator
    Proceedings of 17th IFAC World Congress 6178 - 6183 2008年 [査読無し][通常論文]
  • Yuki Nishimura, Yuh Yamashita
    IFAC Proceedings Volumes 41 2 2808 - 2813 2008年
  • 西村悠樹, 山下裕
    計測自動制御学会論文集 44 1 26 - 35 2008年 [査読有り][通常論文]
  • Nami Nakamura, Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani
    Proceedings of 2007 European Control Conference 5376 - 5382 2007年07月 [査読有り][通常論文]
  • 都築卓有規, 桑田幸典, 山下裕
    計測自動制御学会論文集 43 2 85 - 92 計測自動制御学会 2007年02月 [査読有り][通常論文]
  • Nami Nakamura, Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani
    IFAC Proceedings Volumes (IFAC-PapersOnline) 7 1 107 - 112 2007年 
    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.
  • Nami Nakamura, Hisakazu Nakamura, Yuh Yamashita
    PROCEEDINGS OF THE 46TH IEEE CONFERENCE ON DECISION AND CONTROL, VOLS 1-14 3770 - + 2007年 [査読有り][通常論文]
     
    In this paper, we propose an homogeneous stabilizing controller for input-affine homogeneous systems. Moreover, we provide an homogeneous inverse optimal controller.
  • 大室 朗, 山下 裕, 島 公脩
    計測自動制御学会論文集 43 10 901 - 908 The Society of Instrument and Control Engineers 2007年 [査読無し][通常論文]
     
    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.
  • Miao Du, Yuh Yamashita
    PROCEEDINGS OF THE 2007 IEEE CONFERENCE ON CONTROL APPLICATIONS, VOLS 1-3 1292 - 1297 2007年 [査読有り][通常論文]
     
    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.
  • Nami Nakamura, Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani
    PROCEEDINGS OF SICE ANNUAL CONFERENCE, VOLS 1-8 1238 - + 2007年 [査読有り][通常論文]
     
    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.
  • Kazuki Takeharai, Takayuki Tsuzuki, Yuh Yamashita
    PROCEEDINGS OF SICE ANNUAL CONFERENCE, VOLS 1-8 104 - + 2007年 [査読有り][通常論文]
     
    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年 [査読無し][通常論文]
  • Yoshinori Hirose, Yuh Yamashita
    PROCEEDINGS OF SICE ANNUAL CONFERENCE, VOLS 1-8 1259 - + 2007年 [査読有り][通常論文]
     
    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.
  • Nami Nakamura, Hisakazu Nakamura, Yuh Yamashita
    Proceedings of the IEEE Conference on Decision and Control 80 - 85 2007年 [査読有り][通常論文]
     
    In this paper, we propose an homogeneous stabilizing controller for input-affine homogeneous systems. Moreover, we provide an homogeneous inverse optimal controller. © 2007 IEEE.
  • Ryuji Enomoto, Yukishige Izue, Yuh Yamashita
    2007 INTERNATIONAL CONFERENCE ON CONTROL, AUTOMATION AND SYSTEMS, VOLS 1-6 1487 - + 2007年 [査読有り][通常論文]
     
    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.
  • Takayuki Tsuzuki, Kousuke Kuwada, Yuh Yamashita
    Proceedings of the 45th IEEE Conference on Decision and Control 5114 - 5119 IEEE 2006年12月 [査読有り][通常論文]
  • Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani
    Proceedings of the 45th IEEE Conference on Decision and Control 4230 - 4235 IEEE 2006年12月 [査読有り][通常論文]
  • 大室 朗, 山下 裕, 島 公脩
    計測自動制御学会論文集 42 10 1100 - 1106 The Society of Instrument and Control Engineers 2006年10月 [査読有り]
     
    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.
  • 中村 文一, 山下 裕, 西谷 紘一
    計測自動制御学会論文集 42 8 894 - 901 The Society of Instrument and Control Engineers 2006年08月 [査読有り][通常論文]
     
    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.
  • Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani
    17th International Symposium on Mathematical Theory of Networks and Systems 2799 - 2804 2006年07月 [査読有り][通常論文]
  • Stabilization Problem of 1-Input Underactuated Mechanics
    Yuki Nishimura, Yuh Yamashita
    17th International Symposium on Mathematical Theory of Networks and Systems 1018 - 1023 2006年07月 [査読有り][通常論文]
  • 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年07月 [査読有り][通常論文]
  • 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年07月 [査読有り][通常論文]
  • 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年07月 [査読有り][通常論文]
  • 細川 雄史, 中村 文一, 西谷 紘一, 山下 裕
    日本ロボット学会誌 24 2 232 - 239 The Robotics Society of Japan 2006年02月 [査読有り][通常論文]
     
    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.
  • Hisakazu Nakamura, Gou Nishida, Hirokazu Nishitani, Yuh Yamashita
    2006 SICE-ICASE INTERNATIONAL JOINT CONFERENCE, VOLS 1-13 33 - + 2006年 [査読無し][通常論文]
     
    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.
  • 都築 卓有規, 山下 裕
    計測自動制御学会論文集 42 6 643 - 650 The Society of Instrument and Control Engineers 2006年 
    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.
  • 喜種 奈美, 中村 文一, 山下 裕, 西谷 紘一
    計測自動制御学会論文集 42 1 26 - 34 計測自動制御学会 2006年01月 [査読有り][通常論文]
  • 中村 文一, 山下 裕, 西谷 紘一
    システム制御情報学会 研究発表講演会講演論文集 6 231 - 231 システム制御情報学会 2006年 
    近年非ホロノミックシステムに対する制御系設計が盛んに研究されているが，車両型移動ロボットに対して，大域的に有限時間で整定する制御器はこれまで得られていない．本研究では，車両型移動ロボットに対し，大域的に有限時間で原点に整定する制御器を提案し，システムが振動的な挙動を示さないパラメータを明らかにする．最後に，コンピュータシミュレーションにより提案する制御則の有効性を確認する．．
  • 木元 隆盛, 大室 朗, 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 6 46 - 46 システム制御情報学会 2006年 
    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。
  • Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani
    PROCEEDINGS OF THE 45TH IEEE CONFERENCE ON DECISION AND CONTROL, VOLS 1-14 4234 - + 2006年 [査読有り][通常論文]
     
    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年08月 [査読有り][通常論文]
  • Takayuki Tsuzuki, Yuh Yamashita, Ryuji Enomoto
    IFAC Proceedings Volumes (Proc. IFAC World Congress 2005) 38 1 640 - 645 2005年07月 [査読有り][通常論文]
  • Yuh Yamashita, Takayuki Tsuzuki, Hisakazu Nakamura
    2005 44th IEEE Conference on Decision and Control & European Control Conference, Vols 1-8 5444 - 5449 2005年 [査読有り][通常論文]
     
    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.
  • H Nakamura, T Kaji, H Nishitani, Y Yamashita
    2005 IEEE INTERNATIONAL CONFERENCE ON CONTROL APPLICATIONS (CCA), VOLS 1AND 2 1569 - 1574 2005年 [査読無し][通常論文]
     
    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年 [査読無し][通常論文]
  • Nonlinear continuous-time reference governors for constrained nonlinear systems
    16th IFAC World Congress (CD-ROM) Fr-M08-TO/6  2005年 [査読無し][通常論文]
  • 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年 [査読無し][通常論文]
  • 喜種 奈美, 中村 文一, 山下 裕, 西谷 紘一
    計測自動制御学会論文集 41 3 250 - 258 計測自動制御学会 2005年 [査読無し][通常論文]
  • NAKAMURA H.
    16th IFAC World Congress (CD-ROM) Mo-A11-TO/4  2005年 [査読無し][通常論文]
  • 黒岡武俊, 安東雅人, 星一平, 山下裕, 西谷紘一
    ヒューマンファクターズ 9 2 114 - 122 日本プラント・ヒューマンファクター学会 2005年01月 [査読有り][通常論文]
  • 山下 裕, 中村 文一, 西谷 紘一
    計測自動制御学会論文集 40 11 1071 - 1077 計測自動制御学会 2004年11月30日 [査読無し][通常論文]
  • Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani
    IFAC Proceedings Volumes (Part of special issue: 6th IFAC Symposium on Nonlinear Control Systems) 37 13 733 - 738 2004年09月 [査読有り][通常論文]
  • YH Jin, Y Yamashita, H Nishitani
    COMPUTERS & CHEMICAL ENGINEERING 28 10 1967 - 1980 2004年09月 [査読無し][通常論文]
     
    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.
  • O Orapimpan, A Kurosaki, T Kurooka, Y Yamashita, H Nishitani
    INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH 43 14 3731 - 3740 2004年07月 [査読無し][通常論文]
     
    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.
  • 金 銀花, 山下 裕, 西谷 紘一
    ヒューマンファクターズ 9 1 27 - 37 日本プラント・ヒューマンファクター学会 2004年07月 [査読無し][通常論文]
  • N Kidane, H Nakamura, Y Yamashita, H Nishitani
    2004 43RD IEEE CONFERENCE ON DECISION AND CONTROL (CDC), VOLS 1-5 4069 - 4074 2004年 [査読無し][通常論文]
     
    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.
  • N Kidane, Y Yamashita, H Nakamura, H Nishitani
    SICE 2004 ANNUAL CONFERENCE, VOLS 1-3 1210 - 1213 2004年 [査読無し][通常論文]
     
    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年 [査読無し][通常論文]
  • 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年 [査読無し][通常論文]
  • H Nakamura, N Kidane, Y Yamashita, H Nishitani
    SICE 2004 ANNUAL CONFERENCE, VOLS 1-3 1874 - 1879 2004年 [査読無し][通常論文]
     
    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.
  • 喜種 奈美, 山下 裕, 西谷 紘一
    計測自動制御学会論文集 Vol. 40 No. 7 721 - 728 The Society of Instrument and Control Engineers 2004年 [査読無し][通常論文]
     
    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.
  • Hiroaki Kosaka, Akira Kurosaki, Atsushi Harada, Yuh Yamashita, Hirokazu Nishitani
    SAE Technical Papers Paper Number: 2004-01-0233  2004年 [査読無し][通常論文]
     
    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年 [査読無し][通常論文]
  • 金 銀花, 山下 裕, 西谷 紘一
    日本プラント・ヒューマンファクター学会誌 8 2 68 - 76 日本プラント・ヒュ-マンファクタ-学会 2004年01月 [査読有り][通常論文]
  • Nami Kidane, Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani
    Proceedings of the IEEE Conference on Decision and Control 4 4069 - 4074 2004年 
    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.
  • 中村 文一, 山下 裕, 西谷 紘一
    計測自動制御学会論文集 39 8 717 - 725 The Society of Instrument and Control Engineers 2003年 [査読無し][通常論文]
     
    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.
  • H Nakamura, Y Yamashita, H Nishitani
    PROCEEDINGS OF THE 2003 AMERICAN CONTROL CONFERENCE, VOLS 1-6 4137 - 4142 2003年 [査読無し][通常論文]
     
    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.
  • 中村 文一, 山下 裕, 西谷 紘一
    計測自動制御学会論文集 39 4 365 - 374 計測自動制御学会 2003年 [査読無し][通常論文]
  • Observer Based I/O-linearizing Control of High Index DAE Systems
    2003 American Control Conference Proceedings 3537 - 3541 2003年 [査読無し][通常論文]
  • O Orapimpan, T Kurooka, Y Yamashita, H Nishitani
    PROCESS SYSTEMS ENGINEERING 2003, PTS A AND B 15 1466 - 1471 2003年 [査読無し][通常論文]
     
    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.
  • Y Yamashita, N Kidane, H Nishitani
    PROCESS SYSTEMS ENGINEERING 2003, PTS A AND B 15 1100 - 1105 2003年 [査読無し][通常論文]
     
    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.
  • YH Jin, T Kurooka, Y Yamashita, H Nishitani
    PROCESS SYSTEMS ENGINEERING 2003, PTS A AND B 15 1280 - 1285 2003年 [査読無し][通常論文]
     
    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.
  • 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 7 2 86 - 96 日本プラント・ヒュ-マンファクタ-学会 2003年01月 [査読無し][通常論文]
  • H Nakamura, Y Yamashita, H Nishitani, H Yamamoto
    SICE 2003 ANNUAL CONFERENCE, VOLS 1-3 1415 - 1418 2003年 [査読有り][通常論文]
     
    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.
  • N Kidane, H Nakamura, Y Yamashita, H Nishitani
    SICE 2003 ANNUAL CONFERENCE, VOLS 1-3 1419 - 1422 2003年 [査読有り][通常論文]
     
    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年12月 [査読有り][通常論文]
  • 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年12月 [査読有り][通常論文]
  • 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年12月 [査読有り][通常論文]
  • 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年10月 [査読有り][通常論文]
  • 今福 啓, 山下 裕, 西谷 紘一
    日本ロボット学会誌 20 7 759 - 770 The Robotics Society of Japan 2002年10月 [査読有り][通常論文]
     
    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年07月 [査読有り][通常論文]
  • 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 7 1 10 - 19 日本プラント・ヒュ-マンファクタ-学会 2002年07月 [査読無し][通常論文]
  • 山下 裕, 大西 規雄, 西谷 紘一
    計測自動制御学会論文集 38 1 18 - 25 計測自動制御学会 2002年01月31日 [査読無し][通常論文]
     
    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.
  • Y Yamashita
    NONLINEAR CONTROL SYSTEMS 2001, VOLS 1-3 633 - 638 2002年 [査読有り][通常論文]
     
    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.
  • 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年01月 [査読有り][通常論文]
  • N Kidane, Y Yamashita, H Nishitani
    SICE 2002: PROCEEDINGS OF THE 41ST SICE ANNUAL CONFERENCE, VOLS 1-5 1966 - 1969 2002年 [査読有り][通常論文]
     
    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.
  • H Nakamura, Y Yamashita, H Nishitani
    SICE 2002: PROCEEDINGS OF THE 41ST SICE ANNUAL CONFERENCE, VOLS 1-5 1974 - 1979 2002年 [査読有り][通常論文]
     
    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.
  • Y Sawamura, Y Yamashita, H Nishitani
    SICE 2002: PROCEEDINGS OF THE 41ST SICE ANNUAL CONFERENCE, VOLS 1-5 219 - 222 2002年 [査読有り][通常論文]
     
    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.
  • N Onishi, Y Yamashita, H Nishitani
    SICE 2002: PROCEEDINGS OF THE 41ST SICE ANNUAL CONFERENCE, VOLS 1-5 2249 - 2254 2002年 [査読有り][通常論文]
     
    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.
  • H Nakamura, Y Yamashita, H Nishitani
    SICE 2002: PROCEEDINGS OF THE 41ST SICE ANNUAL CONFERENCE, VOLS 1-5 1980 - 1983 2002年 [査読有り][通常論文]
     
    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年12月 [査読有り][通常論文]
  • T Kurooka, M Yamakawa, Y Yamashita, H Nishitani
    JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 34 11 1387 - 1395 2001年11月 [査読有り][通常論文]
     
    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年08月 [査読有り][通常論文]
  • 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年08月 [査読有り][通常論文]
  • 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年06月 [査読有り][通常論文]
  • 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 6 1 33 - 44 日本プラント・ヒュ-マンファクタ-学会 2001年04月 [査読有り][通常論文]
  • T Kurooka, M Yamakawa, Y Yamashita, H Nishitani
    HUMAN-COMPUTER INTERACTION - INTERACT'01 609 - 616 2001年 [査読有り][通常論文]
     
    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.
  • N Onishi, Y Yamashita, H Nishitani
    PROCEEDINGS OF THE 40TH IEEE CONFERENCE ON DECISION AND CONTROL, VOLS 1-5 79 - 84 2001年 [査読有り][通常論文]
     
    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.
  • 山下 裕, 西谷 紘一, 島 公脩
    計測自動制御学会論文集 36 12 1101 - 1107 計測自動制御学会 2000年12月31日 [査読無し][通常論文]
  • 福 啓, 山下 裕, 西谷 紘一
    システム制御情報学会誌 44 10 458 - 469 一般社団法人 システム制御情報学会 2000年10月 [査読有り][通常論文]
     
    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.
  • 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 5 2 88 - 98 日本プラント・ヒューマンファクター学会 2000年10月 [査読無し][通常論文]
  • 今福 啓, 山下 裕, 西谷 紘一
    化学工学論文集 26 5 683 - 686 2000年09月 [査読有り][通常論文]
  • K Fujino, K Imafuku, Y Yamashita, H Nishitani
    COMPUTERS & CHEMICAL ENGINEERING 24 2-7 303 - 308 2000年07月 [査読有り][通常論文]
     
    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.
  • T Kurooka, Y Yamashita, H Nishitani
    COMPUTERS & CHEMICAL ENGINEERING 24 2-7 551 - 556 2000年07月 [査読有り][通常論文]
     
    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.
  • T Kurooka, Y Yamashita, H Nishitani, Y Hashimoto, M Yoshida, M Numata
    COMPUTERS & CHEMICAL ENGINEERING 24 2-7 887 - 892 2000年07月 [査読有り][通常論文]
     
    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 2000年06月 
    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.
  • 黒岡 武俊, 山下 裕, 西谷 紘一
    化学工学論文集 26 3 406 - 412 2000年 [査読有り][通常論文]
     
    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.
  • Y Yamashita, A Isidori
    PROCEEDINGS OF THE 39TH IEEE CONFERENCE ON DECISION AND CONTROL, VOLS 1-5 1295 - 1300 2000年 [査読有り][通常論文]
     
    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年11月 [査読有り][通常論文]
  • Taketoshi Kurooka, Yuh Yamashita, Hirokazu Nishitani
    IEEE International Conference on Systems, Man, and Cybernetics 407 - 412 1999年10月 [査読有り][通常論文]
  • 大形 明弘, 山下 裕, 西谷 紘一
    化学工学論文集 25 5 721 - 727 1999年09月 [査読有り][通常論文]
  • 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年08月 [査読有り][通常論文]
  • 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年08月 [査読有り][通常論文]
  • 今福 啓, 山下 裕, 西谷紘一
    日本ロボット学会誌 17 5 689 - 695 The Robotics Society of Japan 1999年07月 [査読有り][通常論文]
     
    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.
  • Taketoshi Kurooka, Yuh Yamashita, Hirokazu Nishitani
    The 15th World Congress of International Measurement Confederation (CD-ROM) Paper ID: 18.2.3 - 412 1999年06月 [査読有り][通常論文]
  • 大形 明弘, 山下 裕, 西谷 紘一
    電気学会論文誌. C, 電子・情報・システム部門誌 = The transactions of the Institute of Electrical Engineers of Japan. C, A publication of Electronics, Information and System Society 119 5 615 - 623 電気学会 1999年05月 [査読無し][通常論文]
  • T Kurooka, M Kisa, Y Yamashita, H Nishitani
    ANALYSIS, DESIGN AND EVALUATION OF MAN-MACHINE SYSTEMS 1998 479 - 484 1999年 [査読有り][通常論文]
     
    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.
  • 今福 啓, 山下 裕, 榛葉 貴博, 島 公脩, 西谷 紘一
    計測自動制御学会論文集 35 1 59 - 65 計測自動制御学会 1999年01月 [査読無し][通常論文]
     
    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.
  • 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 3 2 100 - 109 日本プラント・ヒュ-マンファクタ-学会 1998年10月 [査読無し][通常論文]
  • 山下 裕, 島 公脩
    計測自動制御学会論文集 34 6 571 - 576 計測自動制御学会 1998年06月30日 [査読無し][通常論文]
     
    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年 [査読有り][通常論文]
  • 大形 明弘, 山下 裕, 西谷 紘一
    化学工学論文集 24 2 291 - 298 1998年 [査読有り][通常論文]
     
    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.
  • Y Yamashita, T Bono, M Shima, H Nishitani
    NONLINEAR CONTROL SYSTEMS DESIGN 1998, VOLS 1& 2 195 - 200 1998年 [査読有り][通常論文]
     
    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.
  • Y Yamashita, M Shima
    NONLINEAR ANALYSIS-THEORY METHODS & APPLICATIONS 30 4 2285 - 2290 1997年12月 [査読有り][通常論文]
  • M Shima, Y Yamashita
    NONLINEAR ANALYSIS-THEORY METHODS & APPLICATIONS 30 4 2279 - 2284 1997年12月 [査読有り][通常論文]
  • 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 2 2 106 - 115 日本プラント・ヒュ-マンファクタ-学会 1997年10月 [査読有り][通常論文]
  • 中山 慶彦, 北島 禎二, 山下 裕, 西谷 紘一
    化学工学 61 8 612 - 613 化学工学会 1997年08月05日 [査読無し][通常論文]
  • 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年07月 [査読有り][通常論文]
  • 山下 裕, 島 公脩
    計測自動制御学会論文集 33 3 189 - 194 計測自動制御学会 1997年03月31日 [査読無し][通常論文]
     
    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.
  • A Ohgata, Y Yamashita, H Nishitani
    COMPUTERS & CHEMICAL ENGINEERING 21 Supplement 1 S131 - S136 1997年 [査読有り][通常論文]
     
    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.
  • Y Yamashita, Y Ikuno, M Shima
    PROCEEDINGS OF THE 35TH IEEE CONFERENCE ON DECISION AND CONTROL, VOLS 1-4 3804 - 3809 1996年 [査読有り][通常論文]
     
    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.
  • 山下 裕, 宮本 潤一, 島 公脩
    システム制御情報学会論文誌 7 4 134 - 141 一般社団法人 システム制御情報学会 1994年04月 [査読有り][通常論文]
     
    In this paper, the adaptive multi-step learning control for continuous-time linear system is studied. Input function uk+1 (t) is calculated from the triplets (uk, ek, ek) and (uk-1, ek-1, ek-1) where ek 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.
  • 山下 裕, 佐藤 友彦, 島 公脩
    システム制御情報学会論文誌 4 6 245 - 251 一般社団法人 システム制御情報学会 1991年06月 [査読有り][通常論文]
     
    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.
  • 山下 裕, 島 公脩
    システム制御情報学会論文誌 3 9 277 - 286 一般社団法人 システム制御情報学会 1990年09月 [査読有り][通常論文]
     
    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.
  • 山下 裕, 島 公脩
    計測自動制御学会論文集 26 9 p1009 - 1014 計測自動制御学会 1990年09月 [査読無し][通常論文]
  • 細川 民樹, 山下 裕, 島 公脩
    計測自動制御学会論文集 26 4 p467 - 473 計測自動制御学会 1990年04月 [査読無し][通常論文]
  • 山下 裕, 島 公脩
    システム制御情報学会論文誌 1 3 108 - 116 一般社団法人 システム制御情報学会 1988年03月 [査読有り][通常論文]
     
    In this paper, we study the block decoupling problem of nonlinear systems with Cω-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 zI(x).Then, the block decoupling problem is solvable if and only if each row of D(G)zI(x) is zero vector or is linearly independent of rows of other D(G)zJ(x)(J=1, …, N; I≠J). The state feedback control law which accomplishes the block decoupling is derived from zI(x).
  • 山下 裕, 島 公脩
    システムと制御 31 6 p450 - 456 日本自動制御協会 1987年06月 [査読無し][通常論文]

MISC

書籍等出版物

  • 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年 (ISBN: 4339031674)
  • 「非線形システム論」
    計測自動制御学会 1993年

担当経験のある科目（授業）

  • システム制御理論特論北海道大学
  • メカトロニクス基礎北海道大学
  • ディジタル制御北海道大学
  • 線形システム論北海道大学
  • 非線形システム論北海道大学

共同研究・競争的資金等の研究課題

  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2019年04月 -2022年03月 
    代表者 : 山下 裕, 小林 孝一
     
    エネルギー消費最小の定常点と状態の目標値が一致しない場合の省エネルギーな最適制御問題を考え、入力コストを最小限の改変で状態量を含む関数とすることで、問題を定式化し漸近安定性を保証する非線形最適レギュレータを構築した。また、アクチュエータが待機パワーを必要とする場合、冗長入力系では状態量の値に応じて非効率なアクチュエータを休止させる動作が省エネルギーに寄与し、そのような動作を行う最適制御制御器設計法を提案した。さらに、出力値に応じたセンサー値の通信の一時停止を含む制御手法も提案した。
  • 日本学術振興会：科学研究費補助金(基盤研究(B))
    研究期間 : 2016年04月 -2019年03月 
    代表者 : 山下 裕
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2015年04月 -2018年03月 
    代表者 : 中村 文一, 石川 将人, 西村 悠樹, 福井 善朗, 山下 裕, 佐藤 康之
     
    本研究では，トポロジー：位相幾何学という観点から制御問題を眺めることにより，意志決定と制御を統合するフレームワークの構築を目指した．本研究の主要成果として，最小射影法を用いた目標状態を動的に決定する制御フレームワーク，最小射影法とは異なる概念に基づいた制御リヤプノフ関数設計法である極小接続法，制御バリア関数を用いて人間に意思決定と安全制御を統合する新たな手法の開発に成功した．これらにより，制御リヤプノフ関数・制御バリア関数を用いた意思決定と制御の統合が有用であることを明らかにできた．
  • 日本学術振興会：科学研究費補助金(挑戦的萌芽研究)
    研究期間 : 2014年04月 -2017年03月 
    代表者 : 山下 裕
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2011年04月 -2014年03月 
    代表者 : 中村 文一, 山下 裕, 伊藤 博, 榎本 隆二, 福井 善朗
     
    分解微分を利用した局所半凹制御Lyapunov関数を使ったフィードバック制御則設計法を提案した． また，入力制約がある場合にも適用可能であることを示した．また，局所半凹制御Lyapunov関数を使ったJurdjevic-Quinn型制御則においてはかならずCaratheodory解が存在することを明らかにした． 最小射影法における特異点消去現象を解析し，特異点配置法を提案した． 動的拡大を行ったシステムに対する制御Lyapunov関数を最小射影することにより，もとのシステムに対する静的な制御Lyapunov関数及び静的なフィードバック制御則を設計する手法を提案した．
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2011年 -2013年 
    代表者 : 中村 奈美, 山下 裕, 中村 文一
     
    多様体上の非線形システムに対して，Lagrange安定性と入力状態安定性を定義した．さらに，連続正定プロパー関数を用いて安定であるための必要十分条件を明らかにした．また，車両型移動ロボットの障害物回避問題に対して，ISS制御Lyapunov関数および入力状態安定化制御則を設計した．提案した制御則の有効性をコンピュータシミュレーションによって確認した．多様体上の一般的な非線形システムに対して，サンプル入力状態安定化制御問題則を提案した．
  • 日本学術振興会：科学研究費補助金(基盤研究(B))
    研究期間 : 2010年 -2012年 
    代表者 : 山下 裕
     
    本研究では、動的な制御対象の状態空間を連続的あるいは離散的な座標を加えることで拡張し、その上で拡張された座標におけるジャンプを許容する制御システムを設計する方法の枠組みを提案した。また、拡張した空間を縮退させ、不連続制御則あるいは離散状態を持つ制御則を再構成する方法も示した。ジャンプを許容することで、動的システムの従来意思決定問題とされていた対象においても数学的な制御則が構成できた。
  • 文部科学省：科学研究費補助金(基盤研究(C))
    研究期間 : 2007年 -2009年 
    代表者 : 山下 裕, 中村 文一, 西田 豪, 西村 悠樹
     
    本研究では、従来の一般的な理論では扱うことのできなかった非ユークリッド空間を含む一般の多様体上の非線形システムを制御する統一的な枠組みを示した。衛星の大域姿勢制御や移動体の障害物回避・鉄棒ロボットなどがそのような問題の例である。そのような対象を安定化するのに必要な不連続性・ロジック・ランダム性などを含む制御則が、本研究の手法によって自動的に設計される。
  • 文部科学省：科学研究費補助金(基盤研究(B))
    研究期間 : 2002年 -2005年 
    代表者 : 西谷 紘一, 今福 啓, 黒岡 武俊, 山下 裕, 小坂 洋明, 中村 文一
     
    プラント運転の異常対応時におけるヒューマンエラーを含むオペレータの行動を、認知情報処理モデルを用いたダイナミックシミュレーションによって理解し、適切な対策を考えるのに役立つ方法を開発することを目的とした本研究で、次の3つの成果を得た。1.心身状態を考慮した新しい認知情報処理モデル(オペレータモデル)をPC上に実装し、ボイラープラントのリアルタイムシミュレータと結合することによって、プラント運転やシミュレータトレーニングの現場で実際に観察されている状況を再現できるようにした。これによって、プラントの異常対応時に起こるヒューマンエラーの発生メカニズムを心身状態の変化を参考にしながら認知情報処理レベルで考察することが可能になった。2.認知情報処理モデルを仮想オペレータとして、プラント運転の基盤であるグラフィック画面の評価および改善に役立てる方法を提案した。これは画面設計者を支援する方法として使用できると共に、オペレータへの種々の支援を検討する際のツールとしても利用することができる。3.オペレータモデルを参考モデルとして、多くの自動車事故の原因となっているドライバの認知・判断エラーを考察するためのドライバモデルを提案した。このモデルを用いることによって、例えば、交差点進入行動を認知情報処理レベルで分解することできる。結果をチャートで表すことによって運転行動の違いを認知情報処理レベルで...
  • 文部科学省：科学研究費補助金(基盤研究(C))
    研究期間 : 2003年 -2004年 
    代表者 : 山下 裕, 中村 文一
     
    1.不連続系に対するリアプノフの逆定理を整理し、シンプルな表現を与えた。それを漸近安定で不連続な同次系に対して用いた場合、同次なリアプノフ関数が得られることを明らかにした。また、同次リアプノフ関数の時間微分を計算することにより、不連続同次系においても同次次数によって収束速度が決定されることを示した。以上の結果を用い、高次スライディング制御系の有限整定性を証明した。2.代表的な非ホロノミック拘束を持つ系であるchained systemに対し、その部分システムに同次有限整定制御を用いることで、時不変不連続な有限整定制御則を導いた。切り替え則として同次な収束時間保証関数を用いているため制御系全体も同次系となり、数学的にも扱いやすい結果が得られた。実用的にも、局所有界な時不変入力で指数安定以上な制御系になっており、これまでにない優れた結果が得られている。チャタリングを防ぐために入力に同次ノルムを掛ける方法も提案した。また、この制御則を、最終的な滑り面に有限整定させるように考えることで、高次chained systemへ適用するように拡張した。また、上記の方法以外にも、非ホロノミック系に対して、微分不可能なリアプノフ関数を与えることで、ある種の有限整定性を持ち局所有界かつ指数安定となる制御則が得られることを示した。3.上記の不連続フィードバックによる非ホロノミック系の安定化制御則を、...
  • 文部科学省：科学研究費補助金(基盤研究(C))
    研究期間 : 2001年 -2003年 
    代表者 : 島 公脩, 横道 政裕, 川村 武, 石動 善久, 山下 裕, 榎本 隆二
     
    まず不変性の概念が制御理論において果たす役割について考察し、以下の成果を得た。(1)パラメータ変動に関する不変性:Frazer-Duncanの定理と単調性の条件を用いて、構造的不確かさのある線形制御系がパラメータの変動区間全体で安定である条件を導びき、単調でない場合の単調化手法を提案した(2)リー代数の構造とフィードバッグ設計:劣駆動機械シネテムの目標軌道追従特性の改善法を提案した。とくに、軸対称劣駆動宇宙機の特異点を通過する軌道生成、および垂直離着陸機の最小位相モデル近似による制御性能の劣化について研究し、有用な方法を与えた。(3)Invarianceの理論の不変的定式化:拘束系の解析力学の最新の研究動向をヨーロッパの文献を中心に調査し、Poisson幾何・Lie亜代数の理論と解析力学との関連の研究の著しい発展、および制御理論への応用の萌芽的研究の出現を確かめ、資料を作成した。(4)不変性・最適性とリー代数:最適特異軌道の存在条件を局所強可到達分布、状態空間、入力空間の次元により分類しBang-bang制御の最適条件、Singular Optimal Controllerの可能性・最短時間制御問題の近似解法を提案した。次に、これらの成果をもし可能ならば統一的に説明するために次の研究を行った。(5)制御理論の構成と入門教程の開発:入力変分および初期状態の変分の双方を考慮した評...
  • 文部科学省：科学研究費補助金(基盤研究(C))
    研究期間 : 2000年 -2002年 
    代表者 : 山下 裕, 黒岡 武俊
     
    本研究では、微分・代数方程式(以下、DAE, differential-algebraic equation)で与えられた非線形システムの制御系設計問題について研究した。非線形の場合、線形のディスクリプタ形式と異なり行列演算だけで冗長度の無い常微分方程式系に変換することができず、非線形代数方程式を解いて冗長度を消去する作業は一般に困難である。そこで、本研究では非線形代数方程式を解くことなく、冗長度を持ったまま制御系設計を行う方法を示した。まず、index 1のDAEシステムに対し、入出力線形化・オブザーバ設計を行った。その際の大域的安定化条件を示した。そこでは冗長度が消えるように、オブザーバのダイナミクスにおいて代数方程式からなる不変多様体に有限時間整定する設計を採用した。次にhigh indexを持つ系に対し、インパルスモードを持つ場合を含めて、冗長な常微分方程式系に変換する方法を2つ示した。一つは、インパルスモードの数に応じた積分器を入力に付加し代数方程式を順次微分する方法である。もう一つは、状態フィードバックを用いるKumarらのrugularizingを改良した方法である。オブザーバを使う場合は、必然的に前者の方法を使わざるを得ない。これを用いてindex 1のDAEシステムと同様にhigh index DAEシステムに対し、入出力線形化・オブザーバ設計を行った。入出...
  • 文部科学省：科学研究費補助金(基盤研究(B))
    研究期間 : 2000年 -2001年 
    代表者 : 西谷 紘一, 黒岡 武俊, 山下 裕
     
    これまで10極の脳波データを用いて人間の論理的思考状態を推定することをオフラインで行っていたが、これをオンラインで行うための基礎的検討を行った。まず、論理的思考を必要とする数学問題解答実験を使って、線形モデルよりもニューラルネットワークモデルの方が精度のよい推定ができることを確認した。次に、このモデルを用いてオンライン・リアルタイムで思考状態を推定するプロトタイプシステムを試作した。続いてこの装置を使って数学問題解答時の被験者の思考状態を推定した結果、3つのモードの正認識率および誤認識率の平均がそれぞれ68%と9%になった。これによって、リアルタイムで思考状態を測定することに目処をたてることができた。次に、より簡単に測定できる生理指標を用いて思考状態を測定する方法について検討した。脳波以外の生理指標として心電、瞬目、呼吸、発汗、脈波、体温のそれぞれについて思考状態との関係を調べた結果、心電、瞬目、呼吸曲線が使えることがわかった。しかし、思考状態のモードごとに推定精度のよい生理指標が異なることから、これら3種類の生理指標を併用する新しい複合モデルを考案した。この結果、被験者の日変化にも安定して、各モードについて60〜70%の精度で推定できることが確認できた。一方、シミュレーション環境における緊急対応訓練を収録したビデオ映像からオペレータの思考状態を判定する支援システムを開発した...
  • 文部科学省：科学研究費補助金(基盤研究(C))
    研究期間 : 1997年 -1998年 
    代表者 : 西谷 紘一, 北島 禎二, 黒岡 武俊, 山下 裕
     
    プラントワイド制御システムは連続制御システムおよびシーケンス制御システムから構成される。さらに通常はプラントオペレータがこの制御システムを使って監視操作を行っている。このような性質の異なる制御要素を含む運転制御システムを設計する際にはダイナミックシミュレーションによる特性評価が必要になる。このため平成9年度は、連続プロセス、離散事象、シーケンス制御を含むプラント全体のシミュレーションを実行するための系統的な方法について検討した。モデリングの基本的な考え方をまとめたあと、混合系のための汎用シミュレーションプログラムを開発した。平成10年度には、プラントワイドの制御システムの代表例として、パイプレスバッチプラントにおけるシステムの運用について考察した。各操作タスクを実行するステーションへ容器(槽)を移動させることによって、製品製造の各工程を順次実行するこの方式の運用(制御)のモデル化を行った。つづいて各設備の台数やレイアウト、移動槽の移動ルール、ジョブのスケジューリングなどの設計要素とプラントのパフォーマンスの関係を調べた。静的および動的要因が複雑に絡んだパイプレスバッチプラントの設計問題はプラントワイドの制御(運用)システムの設計でもある。このような設計問題に対して、設計案の提案とシミュレーションによる設計評価をくりかえす実用的なプラント設計手法を提案し、具体的にモデリング部、...
  • 文部科学省：科学研究費補助金(一般研究(B))
    研究期間 : 1994年 -1995年 
    代表者 : 島 公脩, 川村 武, 山下 裕, 石動 善久
     
    本年度においては、以下のような成果を得た。1.出力フィードバックによる非線形H^∞制御を用いたモデル追従制御においては非標準H^∞問題を解かなければならない。本研究においては、非標準問題のうち、入力から出力までの直達項のランクがフルランクでない場合と、外乱から観測出力までの直達項のランクがフルランクでない場合の2つについて、十分条件を導いた。非標準問題においては、そのままでは平方完成の作業が不可能であり、Hamilton-Jacobi-Issacs偏微分不等式が定義できない。そこで、目標のL_2ゲインを達成するための散逸不等式に、未定関数を含んだ付加的な項を加え、直達項を見かけ上フルランクとした。その上で平方完成を行い、Hamilton-Jacobi-Issacs偏微分不等式を導いた。最後に、散逸不等式に加えた項が零となるように未定関数を決定し、非標準H^∞制御問題の十分条件・制御則が得られた。この手順のままでは、散逸不等式に加えた項の係数が微小という仮定が必要であるが、その仮定が不要であることも別に証明した。2.線形系に対してパラメータに関して非線形な摂動が加わった場合の系の特性多項式に着目し、安定性について考察した。まず写像定理を拡張し、パラメータに関する多重線形性の仮定を単調性にまで緩め、与えられたパラメータの範囲において系が安定となるための条件を求めた。また、単調性の...
  • 文部科学省：科学研究費補助金(奨励研究(A))
    研究期間 : 1994年 -1994年 
    代表者 : 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。
  • 文部科学省：科学研究費補助金(奨励研究(A))
    研究期間 : 1993年 -1993年 
    代表者 : 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...
  • 文部科学省：科学研究費補助金(一般研究(C))
    研究期間 : 1991年 -1992年 
    代表者 : 島 公脩, 山下 裕, 石動 善久
     
    ベクトル場X=X_0+X_1u^1+…X_mu^mにより系の状態の多様体M上での挙動は表現され、制御入力u=(u^1,…,u^m)をある時間区間[t_0,t_1]において与えれば、系の状態の軌道は定まる。その軌道にそって、微分形式ωが取る値ω(X)を積分すると、この積分は系の出力、リヤプノフ関数、最適制御の評価関数を表現できる。この積分を制御径路積分あるいは略して径路積分と名づける。制御理論は径路積分の性質を研究し設計法を導き出す理論である。まず、この設定を時変的非線形系に拡張し、径路積分に部分積分公式を適用して、入出力関係の多項式表現を導き、積分順序の交換公式を用いて制御径路に沿ったFliess型表現および解析性の仮定のもとでFliessの関数項級数展開公式、Volterra級数型表現を導いた。多項式表現より制御径路に沿った設計条件を導出できる。つぎに、径路積分の出力可制御性の必要十分条件を導出した。その条件は強可到達性を表わす一連のベクトル場に沿っての微分形式ωのリイ微分により表現され、ωが完全微分ならば従来の条件と一致する。また、一般化Legendre-Clebschの条件の等式条件を用いると不変性の条件の導出が簡単になることがわかった。この等式条件はある微分形式が閉形式であることと同値である。経路積分を用いることは、系を余接バンドルとハミルトン形式を用いて表現すること...
  • 非線形制御理論
  • Nonlinear control theory

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