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
中島 共平;小林 孝一;山下 裕

Model Predictive Control of Spatially Distributed Systems with Spatio-Temporal Logic Specifications
Ikkei Komizu, Koichi Kobayashi, Yuh Yamashita
Computation, 12, 10, 196, 196, MDPI AG, 2024年09月30日
研究論文（学術雑誌）, In this paper, for spatially distributed systems, we propose a new method of model predictive control with spatio-temporal logic specifications. We formulate the finite-time control problem with specifications described by SSTLf (signal spatio-temporal logic over finite traces) formulas. In the problem formulation, the feasibility is guaranteed by representing control specifications as a penalty in the cost function. Time-varying weights in the cost function are introduced to satisfy control specifications as well as possible. The finite-time control problem can be written as a mixed integer programming (MIP) problem. According to the policy of model predictive control (MPC), the control input can be generated by solving the finite-time control problem at each discrete time. The effectiveness of the proposed method is presented through a numerical example.

A BDD-Based Approach to Finite-Time Control of Boolean Networks
Fuma MOTOYAMA, Koichi KOBAYASHI, Yuh YAMASHITA
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E107.A, 5, 793, 798, Institute of Electronics, Information and Communications Engineers (IEICE), 2024年05月01日
研究論文（学術雑誌）

Lyapunov-based approach to event-triggered control with self-triggered sampling
Shota Nakayama, Koichi Kobayashi, Yuh Yamashita
Advanced Robotics, 38, 9-10, 603, 609, Informa UK Limited, 2024年02月28日
研究論文（学術雑誌）

On reward distribution in reinforcement learning of multi-agent surveillance systems with temporal logic specifications
Keita Terashima, Koichi Kobayashi, Yuh Yamashita
Advanced Robotics, 2024年02月14日
研究論文（学術雑誌）

Online Optimization of Pickup and Delivery Problem Considering Feasibility
Ryo Matsuoka, Koichi Kobayashi, Yuh Yamashita
Future Internet, 2024年02月
研究論文（学術雑誌）

A BDD-Based Approach to Model Reduction of Boolean Networks
Fuma Motoyama, Koichi Kobayashi, Yuh Yamashita
IEEE Transactions on Control of Network Systems, 2024年
研究論文（学術雑誌）

Reinforcement Learning for Multi-Agent Systems with Temporal Logic Specifications
Keita TERASHIMA, Koichi KOBAYASHI, Yuh YAMASHITA
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E107-A, 1, 31, 37, Institute of Electronics, Information and Communications Engineers (IEICE), 2024年01月, ［査読有り］, ［最終著者］
英語, 研究論文（学術雑誌）

Multi-Agent Surveillance Based on Travel Cost Minimization
Kyohei MURAKATA, Koichi KOBAYASHI, Yuh YAMASHITA
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E107-A, 1, 25, 30, Institute of Electronics, Information and Communications Engineers (IEICE), 2024年01月, ［査読有り］, ［最終著者］
英語, 研究論文（学術雑誌）

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］, ［最終著者］
英語, 研究論文（国際会議プロシーディングス）

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］, ［筆頭著者］
英語, 研究論文（国際会議プロシーディングス）

Lyapunov Function-Based Approach to Event-Triggered Control with Self-Triggered Sampling
Nakayama Shota, Kobayashi Koichi, Yamashita Yuh
Proc. of the 2023 International Symposium on Nonlinear Theory and Its Application, 467, 470, 2023年09月, ［査読有り］, ［最終著者］
英語, 研究論文（国際会議プロシーディングス）

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］, ［最終著者］
英語, 研究論文（国際会議プロシーディングス）

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］, ［最終著者］
英語, 研究論文（国際会議プロシーディングス）

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］, ［最終著者］
英語, 研究論文（国際会議プロシーディングス）

Automatic Generation of Control Lyapunov Functions for Vehicle Guidance on Complex Paths
Yuh Yamashita, Wataru Hashimoto, Koichi Kobayashi
IFAC-PapersOnLine, 56, 2, 8036, 8041, Elsevier BV, 2023年07月, ［査読有り］, ［筆頭著者］
英語, 研究論文（国際会議プロシーディングス）

Design of reduced-order and pinning controllers for probabilistic Boolean networks using reinforcement learning
Michiaki Takizawa, Koichi Kobayashi, Yuh Yamashita
Applied Mathematics and Computation, 457, 128211, 128211, Elsevier BV, 2023年07月, ［査読有り］, ［最終著者］
英語, 研究論文（学術雑誌）

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, ［最終著者］
英語, 研究論文（国際会議プロシーディングス）

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］, ［最終著者］
英語, 研究論文（国際会議プロシーディングス）

Fixed Point Preserving Model Reduction of Boolean Networks Focusing on Complement and Absorption Laws
Fuma Motoyama, Koichi Kobayashi, Yuh Yamashita
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences, E106-A, 5, 721, 728, 2023年05月, ［査読有り］, ［最終著者］
英語, 研究論文（学術雑誌）

Detection of False Data Injection Attacks in Distributed State Estimation of Power Networks
Sho Obata, Koichi Kobayashi, Yuh Yamashita
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences, E106-A, 5, 729, 735, Institute of Electronics, Information and Communications Engineers (IEICE), 2023年05月, ［査読有り］, ［最終著者］
英語, 研究論文（学術雑誌）

Block sparse design of distributed controllers for dynamical network systems
Ryosuke Adachi, Yuh Yamashita, Koichi Kobayashi
International Journal of Robust and Nonlinear Control, 33, 1, 49, 66, Wiley, 2023年01月10日, ［査読有り］
英語, 研究論文（学術雑誌）, This study proposes a controller design method based on block sparse optimization for dynamical network systems. The objective of the controller is to stabilize dynamical network systems with a given convergence rate. The block sparse optimization minimizes the number of controlled nodes. This study is unique in that the structure of the controller is constrained by the network topology of the system. Additionally, the proposed design problem is separable in terms of the distributed optimization over networks. The proposed method is applicable to controller design for the pinning control of consensus systems and the optimal vaccine allocation for epidemic spreading processes.

Asymptotic stabilization with group‐wise sparse input based on control Lyapunov function approach
Yuh Yamashita, Kiminori Sakano, Koichi Kobayashi
International Journal of Robust and Nonlinear Control, 33, 1, 35, 48, Wiley, 2023年01月10日, ［査読有り］, ［筆頭著者, 責任著者］
英語, 研究論文（学術雑誌）

Passivity‐based control of nonlinear active dynamic vibration absorber
Sheng Hao, Yuh Yamashita, Koichi Kobayashi
International Journal of Robust and Nonlinear Control, 33, 5, 3247, 3266, Wiley, 2023年01月06日, ［査読有り］
英語, 研究論文（学術雑誌）

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］, ［最終著者］
英語, 研究論文（国際会議プロシーディングス）

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］, ［最終著者］
英語, 研究論文（国際会議プロシーディングス）

Output Feedback Ultimate Boundedness Control with Decentralized Event-Triggering
Koichi KITAMURA, Koichi KOBAYASHI, Yuh YAMASHITA
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, Institute of Electronics, Information and Communications Engineers (IEICE), 2023年, ［査読有り］, ［最終著者］
英語, 研究論文（学術雑誌）

Virtual merge and split at intersection for vehicle platooning based on self-triggered pinning consensus control
Ayaka Tanaka, Koichi Kobayashi, Yuh Yamashita
Advanced Robotics, 37, 1, 1, 10, Informa UK Limited, 2023年01月, ［査読有り］, ［最終著者］
英語, 研究論文（学術雑誌）

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］, ［最終著者］
英語, 研究論文（国際会議プロシーディングス）

Blockchain-Based Optimization of Distributed Energy Management Systems with Real-Time Demand Response
Daiki OGAWA, Koichi KOBAYASHI, Yuh YAMASHITA
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E105-A, 11, 1478, 1485, Institute of Electronics, Information and Communications Engineers (IEICE), 2022年11月, ［査読有り］, ［最終著者］
英語, 研究論文（学術雑誌）

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］, ［最終著者］
英語, 研究論文（国際会議プロシーディングス）

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］, ［最終著者］
英語, 研究論文（国際会議プロシーディングス）

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］, ［最終著者］
英語, 研究論文（国際会議プロシーディングス）

Sensor Scheduling-Based Detection of False Data Injection Attacks in Power System State Estimation
Sho OBATA, Koichi KOBAYASHI, Yuh YAMASHITA
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E105-A, 6, 1015, 1019, Institute of Electronics, Information and Communications Engineers (IEICE), 2022年06月, ［査読有り］, ［最終著者］
英語, 研究論文（学術雑誌）

LMI-Based Design of Output Feedback Controllers with Decentralized Event-Triggering
Koichi KITAMURA, Koichi KOBAYASHI, Yuh YAMASHITA
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E105-A, 5, 816, 822, Institute of Electronics, Information and Communications Engineers (IEICE), 2022年05月, ［査読有り］, ［最終著者］
英語, 研究論文（学術雑誌）

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］, ［最終著者］
英語, 研究論文（国際会議プロシーディングス）

Robust passivity‐based control design for active nonlinear suspension system
Sheng Hao, Yuh Yamashita, Koichi Kobayashi
International Journal of Robust and Nonlinear Control, 32, 1, 373, 392, Wiley, 2022年01月, ［査読有り］
英語, 研究論文（学術雑誌）

Asymptotic stabilization of nonlinear systems with convex-polytope input constraints by continuous input
Yuh Yamashita, Ryosuke Matsukizono, Koichi Kobayashi
Automatica, 138, 110032, 110032, Elsevier BV, 2021年11月, ［査読有り］, ［筆頭著者］
英語, 研究論文（学術雑誌）

Distributed Optimal Estimation with Scalable Communication Cost
Ryosuke Adachi, Yuh Yamashita, Koichi Kobayashi
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences, E104-A, 11, 1470, 1476, Institute of Electronics, Information and Communications Engineers (IEICE), 2021年11月, ［査読有り］
英語, 研究論文（学術雑誌）

On Detection of False Data Injection Attacks in Distributed State Estimation of Power Networks
Sho Obata, Koichi Kobayashi, Yuh Yamashita
2021 IEEE 10th Global Conference on Consumer Electronics (GCCE), 472, 473, IEEE, 2021年10月12日, ［査読有り］, ［最終著者］
英語, 研究論文（国際会議プロシーディングス）

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］
英語, 研究論文（国際会議プロシーディングス）

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］
英語, 研究論文（国際会議プロシーディングス）

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］
英語, 研究論文（国際会議プロシーディングス）

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］
英語, 研究論文（国際会議プロシーディングス）

Construction of ISS Lyapunov functions for Hamiltonian systems with multiple disturbances
Sheng Hao, Yuh Yamashita, Koichi Kobayashi
IFAC-PapersOnLine (Special Issue for Proceedings of 3rd IFAC Conference on Modelling, Identification and Control of Nonlinear Systems), 54, 14, 281, 286, Elsevier BV, 2021年09月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

Decentralized Event-Triggered Control of Discrete-Time Linear Systems via Output Feedback
Koichi Kitamura, Koichi Kobayashi, Yuh Yamashita
IEEE International Symposium on Industrial Electronics, 2021-, Institute of Electrical and Electronics Engineers Inc., 2021年06月20日
英語, 研究論文（国際会議プロシーディングス）, In this paper, event-triggered control over a sensor network is studied as one of the control methods of cyber-physical systems. Event-triggered control is a method that communications occur only when the measured value is widely changed. In the proposed method, by solving an LMI (linear matrix inequality) feasibility problem, we derive an event-triggered output feedback controller such that the closed-loop system is asymptotically stable. First, the problem formulation is given. Next, the control problem is reduced to an LMI feasibility problem. Finally, the proposed method is demonstrated by a numerical example.

Distributed Observer Design on Sensor Networks with Random Communication
Yuh Yamashita, Haruka Sumita, Ryosuke Adachi, Koichi Kobayashi
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E104-A, 3, 613, 621, 2021年03月, ［査読有り］, ［筆頭著者］
英語, 研究論文（学術雑誌）, This paper proposes a distributed observer on a sensor network, where communication on the network is randomly performed. This work is a natural extension of Kalman consensus filter approach to the cases involving random communication. In both bidirectional and unidirectional communication cases, gain conditions that guarantee improvement of estimation error convergence compared to the case with no communication are obtained. The obtained conditions are more practical than those of previous studies and give appropriate cooperative gains for a given communication probability. The effectiveness of the proposed method is confirmed by computer simulations.

Uniformly Ultimate Boundedness Control with Decentralized Event-Triggering
Koichi Kobayashi, Kyohei Nakajima, Yuh Yamashita
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E104-A, 2, 455, 461, 2021年02月, ［査読有り］, ［最終著者］
英語, 研究論文（学術雑誌）

Effectiveness and Limitation of Blockchain in Distributed Optimization: Applications to Energy Management Systems
Daiki Ogawa, Koichi Kobayashi, Yuh Yamashita
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E104-A, 2, 423, 429, Institute of Electronics, Information and Communications Engineers (IEICE), 2021年02月, ［査読有り］, ［最終著者］
英語, 研究論文（学術雑誌）

Sensor Scheduling-Based Detection of False Data Injection Attacks in Power System State Estimation
Sho Obata, Koichi Kobayashi, Yuh Yamashita
Digest of Technical Papers - IEEE International Conference on Consumer Electronics, 2021-, Institute of Electrical and Electronics Engineers Inc., 2021年01月10日
英語, 研究論文（国際会議プロシーディングス）, In state estimation of steady-state power networks, a cyber attack that cannot be detected from the residual (i.e., the estimation error) is called a false data injection attack. In this paper, to enforce security of power networks, we propose a method of detecting a false data injection attack. In the proposed method, a false data injection attack is detected by randomly choosing sensors used in state estimation. The effectiveness of the proposed method is presented by two numerical examples including the IEEE 14-bus system.

Distributed estimation based on weighted data aggregation over delayed sensor networks
Ryosuke Adachi, Yuh Yamashita, Koichi Kobayashi
IFAC Journal of Systems and Control, 14, 100109, 100109, Elsevier BV, 2020年12月, ［査読有り］, ［国際誌］
英語, 研究論文（学術雑誌）

Design of global smooth implicit control Lyapunov function for multiple-integrator system with input constraint
Yuh Yamashita, Naoto Adachi, Ryo Nonaka, Koichi Kobayashi
Systems & Control Letters, 145, 104776, 104776, Elsevier BV, 2020年11月, ［査読有り］, ［筆頭著者, 責任著者］, ［国際誌］
英語, 研究論文（学術雑誌）

Blockchain-Based Optimization of Energy Management Systems with Demand Response
Daiki Ogawa, Koichi Kobayashi, Yuh Yamashita
Proc. of the IEEE 9th Global Conference on Consumer Electronics, 58, 59, Institute of Electronics, Information and Communications Engineers (IEICE), 2020年10月, ［査読有り］, ［最終著者］
英語, 研究論文（国際会議プロシーディングス）

Stochastic Model Predictive Control of Energy Management Systems with Human in the Loop
Shogo Shimamoto, Koichi Kobayashi, Yuh Yamashita
Proc. of the IEEE 9th Global Conference on Consumer Electronics, 60, 61, 2020年10月, ［査読有り］, ［最終著者］
英語, 研究論文（国際会議プロシーディングス）

Active Vibration Control of Nonlinear 2DOF Mechanical Systems via IDA-PBC
Sheng Hao, Yuh Yamashita, Koichi Kobayashi
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E103.A, 9, 1078, 1085, Institute of Electronics, Information and Communications Engineers (IEICE), 2020年09月01日, ［査読有り］
英語, 研究論文（学術雑誌）

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］, ［最終著者］
英語, 研究論文（国際会議プロシーディングス）

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］, ［最終著者］
英語, 研究論文（国際会議プロシーディングス）

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］, ［最終著者］
英語, 研究論文（国際会議プロシーディングス）

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］, ［最終著者］
英語, 研究論文（国際会議プロシーディングス）

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］, ［最終著者］
英語, 研究論文（国際会議プロシーディングス）

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］
英語, 研究論文（国際会議プロシーディングス）

Optimal Regulators for Nonlinear Systems with Incompatible State and Input Cost Functions
Yuh Yamashita, Yuta Sakai, Koichi Kobayashi
IFAC-PapersOnLine (Special issue of 21st IFAC World Congress), 53, 2, 6819, 6824, Elsevier BV, 2020年07月, ［査読有り］, ［筆頭著者, 責任著者］
英語, 研究論文（国際会議プロシーディングス）

Passivity-Based Nonlinear Active Suspension Control Utilizing Relative Information
Sheng Hao, Yuh Yamashita, Koichi Kobayashi
IFAC-PapersOnLine (Special issue of 21st IFAC World Congress), 53, 2, 5586, 5591, Elsevier BV, 2020年07月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

Design of Controller and Observer for Dynamical Network Systems Based on Weighted Degrees
Ryosuke Adachi, Yuh Yamashita, Koichi Kobayashi
IFAC-PapersOnLine (Special issue of 21st IFAC World Congress), 53, 2, 3330, 3335, Elsevier BV, 2020年07月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

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］, ［最終著者］
英語, 研究論文（国際会議プロシーディングス）

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］, ［最終著者］
英語, 研究論文（国際会議プロシーディングス）

Distributed Observer over Delayed Sensor Networks for Systems with Unknown Inputs
ADACHI Ryosuke, YAMASHITA Yuh, KOBAYASHI Koichi
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 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］
英語, 研究論文（学術雑誌）,

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

Dynamic Surveillance by Multiple Agents with Fuel Constraints
Ryo Masuda, Koichi Kobayashi, Yuh Yamashita
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E103-A, 2, 462, 468, 2020年02月, ［査読有り］
英語, 研究論文（学術雑誌）

Self-Triggered Pinning Consensus Control for Multi-Agent Systems
Shun Andoh, Koichi Kobayashi, Yuh Yamashita
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E103.A, 2, 443, 450, Institute of Electronics, Information and Communications Engineers (IEICE), 2020年02月01日, ［査読有り］, ［最終著者］
英語, 研究論文（学術雑誌）

Hierarchical Pinning Control for Consensus of Multi-Agent Systems and Its Application to Vehicle Platooning
Shun Andoh, Koichi Kobayashi, Yuh Yamashita
Proceedings of 2020 IEEE/SICE International Symposium on System Integration, 1064, 1069, 2020年01月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

Robust Active Vibration Controller Design for a Class of Underactuated Nonlinear Systems
Sheng Hao, Yuh Yamashita, Koichi Kobayashi
Proceedings of 2020 IEEE/SICE International Symposium on System Integration, 465, 470, 2020年01月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

Construction Method of Probabilistic Boolean Networks Based on Imperfect Information
Katsuaki Umiji, Koichi Kobayashi, Yuh Yamashita
Algorithms, 12, 12, 268 (9 pages), 2019年12月, ［査読有り］
英語, 研究論文（学術雑誌）

Dynamic Surveillance by Multiple Agents with Fuel Constraints
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］
英語, 研究論文（国際会議プロシーディングス）

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］
英語, 研究論文（国際会議プロシーディングス）

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］
英語, 研究論文（国際会議プロシーディングス）

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］
英語, 研究論文（国際会議プロシーディングス）

Control of Bilateral Teleoperation System Consisting of Heterogeneous Manipulators with Communication Delay
Akihisa Higashino, Yuh Yamashita, Koichi Kobayashi
IFAC PapersOnline (Part of special issue: 11th IFAC Symposium on Nonlinear Control Systems), 52, 16, 747, 752, 2019年09月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

Design and Value Evaluation of Demand Response Based on Model Predictive Control
Kodai Miyazaki, Koichi Kobayashi, Shun-Ichi Azuma, Nobuyuki Yamaguchi, Yuh Yamashita
IEEE Transactions on Industrial Informatics, 15, 8, 4809, 4818, 2019年08月, ［査読有り］
英語, 研究論文（学術雑誌）

Decentralized Event-Triggered Control of Discrete-Time Linear Systems Based on Uniformly Ultimate Boundedness
Koichi Kobayashi, Kyohei Nakajima, Yuh Yamashita
Proceedings of the 2019 Asian Control Conference, 1392, 1397, 2019年06月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

Distributed Estimation Over Delayed Sensor Networks with Cyclic Structure
Ryosuke Adachi, Yuh Yamashita, Koichi Kobayashi
Proceedings of the 2019 Asian Control Conference, 1386, 1391, 2019年06月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

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］
英語, 研究論文（国際会議プロシーディングス）

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］
英語, 研究論文（国際会議プロシーディングス）

Blockchain-Based Distributed Optimization for Energy Management Systems
Daiki Ogawa, Koichi Kobayashi, Yuh Yamashita
Proceedings of 2019 IEEE International Conference on Industrial Cyber Physical Systems, 706, 711, 2019年05月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

Distributed Estimation over Delayed Sensor Network with Scalable Communication
Ryosuke Adachi, Yuh Yamashita, Koichi Kobayashi
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E102-A, 5, 712, 720, 2019年05月, ［査読有り］
英語, 研究論文（学術雑誌）

Computationally Efficient Model Predictive Control for Multi-Agent Surveillance Systems
Koichi Kobayashi, Mifuyu Kido, Yuh Yamashita
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences, E102-A, 2, 372, 378, 2019年02月, ［査読有り］
英語, 研究論文（学術雑誌）

Convergence Rates of Stochastic Homogeneous Systems
Kenta Hoshino, Yuki Nishimura, Yuh Yamashita
Systems & Control Letters, 124, 33, 39, 2019年02月, ［査読有り］
英語, 研究論文（学術雑誌）

Asymptotic stabilization of nonholonomic four-wheeled vehicle with steering limitation
Wataru Hashimoto, Yuh Yamashita, Koichi Kobayashi
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences, E102-A, 1, 227, 234, 2019年01月, ［査読有り］
英語, 研究論文（学術雑誌）

Active Nonlinear Tuned Mass Damper via IDA-PBC
Sheng Hao, Yuh Yamashita, Koichi Kobayashi
Proc. of 2018 IEEE International Conference on Systems, Man, and Cybernetics, 4383, 4388, 2018年10月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

Computationally Efficient Model Predictive Control for Multi-Agent Surveillance Systems
Koichi Kobayashi, Mifuyu Kido, Yuh Yamashita
Proc. of 2018 IEEE International Conference on Systems, Man, and Cybernetics, 2015, 2020, 2018年10月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

Observer Design for Distributed Network Systems with Communication Delays
Ryosuke Adachi, Yuh Yamashita, Koichi Kobayashi
IFAC PapersOnline; Proceedings of the 5th IFAC Conference on Analysis and Control of Chaotic Systems, 51, 33, 115, 125, 2018年10月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

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］
英語, 研究論文（国際会議プロシーディングス）

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］
英語, 研究論文（国際会議プロシーディングス）

Asymptotically Stabilizing Controller Generating Sparse Input for Nonlinear Systems
Yuh Yamashita, Kiminori Sakano, Koichi Kobayashi
Proc. of the 23rd International Symposium on Mathematical Theory of Networks and Systems, 435, 440, 2018年07月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

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］
英語, 研究論文（国際会議プロシーディングス）

Vibration Suppression of Hamiltonian Systems with Velocity and Force Disturbances Using IDA-PBC
Sheng Hao, Yuh Yamashita, Koichi Kobayashi
IFAC Papers Online, Proc. of the Second IFAC Conference on Modelling, Identification and Control of Nonlinear Systems, 51, 13, 285, 290, 2018年06月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

MPC-based Co-design of Control and Routing for Wireless Sensor and Actuator Networks
Dai Satoh, Koichi Kobayashi, Yuh Yamashita
International Journal of Control, Automation and Systems, 16, 3, 953, 960, Institute of Control, Robotics and Systems, 2018年06月01日, ［査読有り］
英語, 研究論文（学術雑誌）, A wireless sensor and actuator network (WSAN) is a class of networked control systems. In WSANs, sensors and actuators are located in a distributed way, and communicate to controllers through a wireless communication network such as a multi-hop network. In this paper, we propose a model predictive control (MPC) method for co-design of control and routing of WSANs. MPC is an optimal control strategy based on numerical optimization. The control input is calculated by solving the finite-time optimal control problem at each discrete time. In the proposed method, a WSAN is modeled by a switched linear system. In the finite-time optimal control problem, a control input and a mode corresponding to a communication path are optimized simultaneously. The proposed method is demonstrated by a numerical example.

Optimal Monitoring of Multiple Agents via Time Sequence-Based Modeling
Ryo MASUDA, Koichi KOBAYASHI, Yuh YAMASHITA
SICE Journal of Control, Measurement, and System Integration, 11, 3, 169, 173, 2018年05月, ［査読有り］
英語, 研究論文（学術雑誌）

Delay-compensated maximum-likelihood-estimation method and its application for quadrotor UAVs
Ryosuke Adachi, Yuh Yamashita
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E101A, 4, 678, 684, Institute of Electronics, Information and Communication, Engineers, IEICE, 2018年04月01日, ［査読有り］
英語, 研究論文（学術雑誌）, This study proposes a maximum-likelihood-estimation method for a quadrotor UAV given the existence of sensor delays. The state equation of the UAV is nonlinear, and thus, we propose an approximated method that consists of two steps. The first step estimates the past state based on the delayed output through an extended Kalman filter. The second step involves calculating an estimate of the present state by simulating the original system from the past to the present. It is proven that the proposed method provides an approximated maximum-likelihood-estimation. The effectiveness of the estimator is verified by performing experiments.

Nonlinear system identification by affine coordinate unification of locally identified MIMO linear systems
Kazuya Nomura, Yuh Yamashita, Koichi Kobayashi
Proc. of the SICE International Symposium on Control Systems 2018, 220, 225, 2018年03月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

Quantized event-triggered control of discrete-time linear systems with switching triggering conditions
Shumpei Yoshikawa, Koichi Kobayashi, Yuh Yamashita
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E101A, 2, 322, 327, Institute of Electronics, Information and Communication, Engineers, IEICE, 2018年02月01日, ［査読有り］
英語, 研究論文（学術雑誌）, 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］
英語, 研究論文（国際会議プロシーディングス）

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］
英語, 研究論文（国際会議プロシーディングス）

BMI approach to design of networked control systems with decentralized event-triggering
Kyohei Nakajima, Koichi Kobayashi, Yuh Yamashita
IEEE Workshop on Signal Processing Advances in Wireless Communications, SPAWC, 2017-, 1, 5, Institute of Electrical and Electronics Engineers Inc., 2017年12月19日, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, In a networked control system (NCS) where plants and controllers are connected through communication networks, it is important to decrease the number of times of communications under preserving of control performances such as optimality and stability. From this viewpoint, event-triggered control has been studied so far. In event-triggered control, the measured signal is sent to the controller only when a triggering condition is satisfied. In this paper, the control problem with decentralized event-triggering conditions is investigated. Here, generalized event-triggering conditions with design parameters are utilized. First, the control problem studied here is formulated. Next, this original problem is reduced to the problem of minimizing an upper bound of the cost function in the original problem. Furthermore, the reduced problem is approximated by a BMI (bilinear matrix inequality) optimization problem. Finally, the proposed method is demonstrated by a numerical example.

Asymptotic Stabilization of Nonholonomic Four-Wheeled Vehicle with Hysteresis Mechanism
Wataru Hashimoto, Yuh Yamashita, Koichi Kobayashi
Proceedings of the 2017 International Symposium on Nonlinear Theory and Its Applications, 30, 33, 2017年12月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

A unification method of locally identified linear systems and reconstruction of nonlinear dynamical model
Kazuya Nomura, Yuh Yamashita, Koichi Kobayashi
IFAC-PapersOnLine, 50, 1, 14004, 14009, Elsevier B.V., 2017年07月01日, ［査読有り］
英語, 研究論文（学術雑誌）, In this study, we propose an identification method of a state-space model for discrete-time SISO nonlinear systems. The first step of the procedure is to construct models which approximate local dynamics around stationary points of the system using a subspace method. The second step is to describe the local models in one unified coordinate using affine coordinate transformations. The coordinate transformations are determined based on the similarity of adjacent local models by the least-squares method. The model describes quasi-steady behavior of the plant. Simulation results of the proposed method are presented.

Data Aggregation based Estimation for Sensor Network with Communication Delay
Ryosuke Adachi, Yuh Yamashita, Koichi Kobayashi
IFAC-PapersOnLine, 50, 1, 2488, 2493, Elsevier B.V., 2017年07月01日, ［査読有り］
英語, 研究論文（学術雑誌）, In this paper, a distributed delay-compensated observer for wireless sensor networks is proposed. Each node of the sensor network aggregates data from the other nodes and sends the aggregated data to the neighbor nodes. All nodes estimate the state variables of a system simultaneously. The observer in each node is similar to the delay-compensated observer with multi-sensor delays proposed by Watanabe. The effectiveness of the proposed method is verified by numerical simulation.

Asymptotic Stabilization of Nonlinear Systems with Convex-Polytope Input Constraints and its Inverse Optimality
Yuh Yamashita, Ryosuke Matsukizono, Koichi Kobayashi
IFAC-PapersOnLine, 50, 1, 1397, 1402, Elsevier B.V., 2017年07月01日, ［査読有り］
英語, 研究論文（学術雑誌）, 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］
英語, 研究論文（国際会議プロシーディングス）

Approximate MLD System Model of Switched Linear Systems for Model Predictive Control
Shin Kanazawa, Koichi Kobayashi, Yuh Yamashita
SICE Journal of Control, Measurement, and System Integration, 10, 3, 136, 140, 2017年05月, ［査読有り］
英語, 研究論文（学術雑誌）

MPC-Based Surveillance over Graphs by Multiple Agents
Mifuyu Kido, Koichi Kobayashi, Yuh Yamashita
SICE Journal of Control, Measurement, and System Integration, 10, 3, 253, 258, 2017年05月, ［査読有り］
英語, 研究論文（学術雑誌）

Linear Quadratic Regulator with Decentralized Event-Triggering
Kyohei Nakajima, Koichi Kobayashi, Yuh Yamashita
IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, E100A, 2, 414, 420, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, 2017年02月, ［査読有り］
英語, 研究論文（学術雑誌）, Event-triggered control is a control method that the measured signal is sent to the controller only when a certain triggering condition on the measured signal is satisfied. In this paper, we propose a linear quadratic regulator (LQR) with decentralized triggering conditions. First, a suboptimal solution to the design problem of LQRs with decentralized triggering conditions is derived. A state-feedback gain can be obtained by solving a convex optimization problem with LMI (linear matrix inequality) constraints. Next, the relation between centralized and decentralized triggering conditions is discussed. It is shown that control performance of an LQR with decentralized event-triggering is better than that with centralized event-triggering. Finally, a numerical example is illustrated.

Periodic Model Predictive Control of Multi-Hop Control Networks
Dai Satoh, Koichi Kobayashi, Yuh Yamashita
IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, E100A, 2, 406, 413, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, 2017年02月, ［査読有り］
英語, 研究論文（学術雑誌）, In this paper, a new method of model predictive control (MPC) for a multi-hop control network (MHCN) is proposed. An MHCN is a control system in which plants and controllers are connected through a multi-hop wireless network. In the proposed method, (i) control inputs and (ii) paths used in transmission of control inputs are computed with constant period by solving the finite-time optimal control problem. First, a mathematical model for expressing an MHCN is proposed. This model is given by a switched linear system, and is compatible with MPC. Next, the finite-time optimal control problem using this model is formulated, and is reduced to a mixed integer quadratic programming problem. Finally, a numerical example is presented to show the effectiveness of the proposed method.

Quantized Event-Triggered Control of Discrete-Time Linear Systems with Switching Triggering Conditions
Shumpei Yoshikawa, Koichi Kobayashi, Yuh Yamashita
2017 56TH ANNUAL CONFERENCE OF THE SOCIETY OF INSTRUMENT AND CONTROL ENGINEERS OF JAPAN (SICE), 313, 316, IEEE, 2017年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, Event-triggered control is a method that the control input is updated only when a certain triggering condition is satisfied. In networked control systems, quantization errors via A/D conversion should be considered. In this paper, a new method for quantized event-triggered control with switching triggering conditions is proposed. For a discrete-time linear system, we consider the problem of finding a state-feedback controller such that the closed-loop system is uniformly ultimately bounded in a certain ellipsoid. This problem is reduced to an LMI (Linear Matrix Inequality) optimization problem. The volume of the ellipsoid can be adjusted.

Optimal Monitoring of Multiple Agents via Time Sequence-Based Modeling
Ryo Masuda, Koichi Kobayashi, Yuh Yamashita
2017 56TH ANNUAL CONFERENCE OF THE SOCIETY OF INSTRUMENT AND CONTROL ENGINEERS OF JAPAN (SICE), 168, 171, IEEE, 2017年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, The multi-agent monitoring (surveillance) problem over graphs is to find trajectories of multiple agents that travel each node as evenly as possible. This problem has several applications such as city safety management and disaster rescue. In our previously proposed method, the finite-time optimal surveillance problem was formulated, and was reduced to a mixed integer linear programming (MILP) problem. Based on the policy of model predictive control, an optimal trajectory is generated by solving the MILP problem at each discrete time. However, the computation time for solving the MILP problem is frequently long. In this paper, to reduce the computation time of the MILP problem, a modeling method of graphs is proposed. In this method, the adjacency relation is time varying depending on the current position of agents. Since redundant arcs are eliminated, the computation time is improved. The effectiveness of the proposed method is demonstrated by numerical simulations.

Stochastic Model Predictive Control of Multi-Hop Control Networks with Packet Dropouts
Dai Satoh, Koichi Kobayashi, Yuh Yamashita
2017 56TH ANNUAL CONFERENCE OF THE SOCIETY OF INSTRUMENT AND CONTROL ENGINEERS OF JAPAN (SICE), 164, 167, IEEE, 2017年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, A multi-hop control network (MHCN) is a control system in which plants and controllers are connected through a multi-hop wireless network. An MHCN is one of the typical examples in cyber-physical systems. In this paper, we propose a new method of stochastic model predictive control for MHCNs with packet dropouts. In the proposed method, a given MHCN is modeled by a stochastic switched system. Then, we consider the finite-time optimal control problem of minimizing the cost function given by the quadratic form with respect to the expected value of the state and the control input. This problem is reduced to a mixed integer programming problem. By solving it, both communication paths and control inputs are optimized simultaneously.

Potential Game on Measures and its Dynamical Behavior
Yuh Yamashita
2017 56TH ANNUAL CONFERENCE OF THE SOCIETY OF INSTRUMENT AND CONTROL ENGINEERS OF JAPAN (SICE), 209, 213, IEEE, 2017年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, 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］
英語, 研究論文（国際会議プロシーディングス）

Backstepping for Set-valued Upper Control Laws and Its Application to Control Allocation Problem
Daiki Suzuki, Yuh Yamashita, Koichi Kobayashi
Proceedings of the 2016 IEEE International Conference on Systems, Man, and Cybernetics, 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］
英語, 研究論文（国際会議プロシーディングス）, 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］
英語, 研究論文（国際会議プロシーディングス）

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］
英語, 研究論文（国際会議プロシーディングス）

Global Asymptotic Stabilization of Nonlinear Deterministic Systems Using Wiener Processes
Kenta Hoshino, Yuki Nishimura, Yuh Yamashita, Daisuke Tsubakino
IEEE TRANSACTIONS ON AUTOMATIC CONTROL, 61, 8, 2318, 2323, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2016年08月, ［査読有り］
英語, 研究論文（学術雑誌）, 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］
英語, 研究論文（国際会議プロシーディングス）

集合値で表される上位制御則に対するバックステッピングと入力分配問題への応用
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］
日本語, 研究論文（学術雑誌）, This paper provides a new framework of control allocation of over-actuated system for static optimization of inputs via dynamical extension and potential approach. The static optimization of the control allocation is performed in real-time approximately, by varying the input according to the potential. To ensure asymptotic stability of the controlled system, we extends the backstepping method to our cases where more flexible additional potential can be used. Under the conditions on the set of the minimizer, the growth rate around the set, and the unimodality of the additional potential with some auxiliary assumptions, the extended potential function becomes a control Lyapunov function of the augmented system. The effectiveness of the proposed method is demonstrated by simulations.

Linear Quadratic Regulator with Decentralized Event-Triggering
Kyohei Nakajima, Koichi Kobayashi, Yuh Yamashita
PROCEEDINGS OF THE IECON 2016 - 42ND ANNUAL CONFERENCE OF THE IEEE INDUSTRIAL ELECTRONICS SOCIETY, 5374, 5379, IEEE, 2016年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, Event-triggered control is a control method that the measured signal is sent to the controller only when a certain condition on the measured signal is satisfied. In this paper, we propose a decentralized event-triggered linear quadratic regulator (LQR). First, a suboptimal solution to the decentralized event-triggered LQR problem is derived. A state-feedback gain can he obtained by solving an LMI (linear matrix inequality) optimization problem. Next, the relation between centralized and decentralized event-triggered LQR problems is discussed. It is shown that control performance of a decentralized event triggered LQR is better than that of a centralized event-triggered LQR. Finally, a numerical example is illustrated.

Asymptotic Stabilization of Nonholonomic Four-Wheeled Vehicle with Steering Limitation based on Lyapunov Function Approach
W. Hashimoto, Y. Yamashita, R. Nonaka, K. Kobayashi
IFAC PAPERSONLINE, 49, 18, 235, 240, ELSEVIER SCIENCE BV, 2016年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, In this paper, we propose a new control law for the asymptotic stabilization of a four-wheeled vehicle with a steering angle limitation. The control law is based on a locally semiconcave control Lyapunov function (LS-CLF) for the chained system proposed by Kimura et al. (2015) that is converted by coordinate and input transformations without singular points. We confirm that the LS-CLF is also effective for the four-wheeled vehicle case, i.e., such inputs exist in the input constraint that decrease the LS-CLF. We also design a control law by using the LS-CLF and steering angle constraint that achieves asymptotic stabilization of the origin of a four-wheeled system while avoiding pivot turns. We confirm the effectiveness of the proposed control law via a computer simulation and an experiment. (C) 2016, IFAC (International Federation of Automatic Control)Hosting by Elsevier Ltd. All rights reserved.

Multiple obstacle avoidance of four-wheeled vehicle with steering limitation using nondifferentiable control Lyapunov function
Ryo Nonaka, Yuh Yamashita, Daisuke Tsubakino
ADVANCED ROBOTICS, 30, 1, 15, 28, TAYLOR & FRANCIS LTD, 2016年01月, ［査読有り］
英語, 研究論文（学術雑誌）, Controlling a mobile robot in a space with obstacles is a well-known problem in robotics. The control objective is for the mobile robot to reach a goal point with obstacle avoidance. In this paper, we specially consider the multiple obstacle avoidance problem for particularly a four-wheeled vehicle. Assuming that the shapes and locations of the obstacles are known, we propose a design method of a nondifferentiable navigation function, which guides a vehicle at the desired point. The control law for the four-wheeled vehicle is obtained from the extended function of the navigation function. As four-wheeled vehicles cannot move sideways because of their nonholonomic constraint, the proposed control law addresses this difficulty by considering a decrease in the control Lyapunov function, and can be applied to vehicles with steering limitations. Moreover, the control law makes it possible for the vehicles to achieve an n-point turn automatically without the need for any rule-based decision-making or heuristic method. The four-wheeled vehicle can reach the goal point from any initial point under the proposed control law. Our experimental results with a small four-wheeled vehicle are presented at the end of this paper.

Vibration suppression for mass-spring-damper systems with a tuned mass damper using interconnection and damping assignment passivity-based control
Takashi Aoki, Yuh Yamashita, Daisuke Tsubakino
INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, 26, 2, 235, 251, WILEY, 2016年01月, ［査読有り］
英語, 研究論文（学術雑誌）, This paper considers a vibration suppression control method using feedback for a mass-spring-damper system with a tuned mass damper. For vibration suppression, we adopt the interconnection and damping assignment passivity-based control, whereby the system is transformed to a system with a skyhook damper with an artificial structure matrix. The feedback law includes no accelerometer signal and uses only information on relative displacements and velocities. The proposed control method can simultaneously suppress the influences of the floor vibration and the disturbance force acting on the main body. A guideline for choosing parameters of the desired system is shown. The proposed method can be easily extended to nonlinear cases, which is demonstrated for a nonlinear-spring case. We also show the input-to-state stability property of closed-loop systems for linear cases and nonlinear cases. Copyright (C) 2015 John Wiley & Sons, Ltd.

Continuous-time delayed feedback control for chaotic systems using complex number observer
Yuh Yamashita
IFAC-PapersOnLine, 28, 18, 199, 204, 2015年11月01日, ［査読有り］, ［筆頭著者, 最終著者, 責任著者］
英語, 研究論文（国際会議プロシーディングス）, 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
英語, 研究論文（国際会議プロシーディングス）

最小射影法を使ったPVTOLシステムに対する静的状態フィードバック制御系設計
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］
日本語, 研究論文（学術雑誌）, "Dynamic extension" is commonly used for stabilization of planar vertical takeoff and landing (PVTOL) system. Most of controllers designed by this method suffer from singularities of division-by-zero. We propose a "static" control Lyapunov function (CLF) design method for a PVTOL system by using a CLF obtained by dynamic extension and minimum projection method. Then, we design an inverse optimal controller with the designed static CLF. Moreover, we show that the proposed controller successfully stabilizes a desired operating point even in the neighborhood of the singularity where the conventional dynamic extension can not stabilize.

Asymptotic Stabilization of Two-Wheeled Mobile Robot via Locally Semiconcave Generalized Homogeneous Control Lyapunov Function
Shunsuke KIMURA, Hisakazu NAKAMURA, Yuh YAMASHITA
SICE Journal of Control, Measurement, and System Integration, 8, 2, 122, 130, The Society of Instrument and Control Engineers, 2015年03月, ［査読有り］
英語, 研究論文（学術雑誌）, A locally semiconcave control Lyapunov function exists for every globally asymptotically controllable system; however for nonholonomic systems, the issue of a locally semiconcave generalized homogeneous control Lyapunov function is not investigated. In this paper, the authors propose a locally semiconcave generalized homogeneous control Lyapunov function for Brockett integrator as a canonical form of nonholonomic systems. Moreover, the authors propose an exponentially stabilizing controller for a two-wheeled mobile robot with the function. The effectiveness of the proposed method are confirmed by computer simulation and an experiment, and advantages over previously proposed controllers are confirmed by experiments.

Stabilization of Artstein's Circle by Continuous Stochastic Feedback
Kenta Hoshino, Yuki Nishimura, Yuh Yamashita, Jun Yoneyama
2015 IEEE CONFERENCE ON CONTROL AND APPLICATIONS (CCA 2015), 257, 262, IEEE, 2015年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, This paper presents the asymptotic stabilization of the Artstein's circle using stochastic processes in a control law. To construct a C-2 control Lyapunov function (CLF) for a stabilization method using stochastic processes, we synthesize a nonsmooth CLF for a nonsmooth stabilization method and a smooth function. By synthesizing these functions, we obtain a C-2 CLF. By this C-2 CLF, we can obtain a continuous stabilizing feedback using stochastic processes for the Artstein's circle.

Delay-Compensated Maximum Likelihood Estimation Method for Quadrotor UAV
Ryosuke Adachi, Yuh Yamashita
2015 IEEE CONFERENCE ON CONTROL AND APPLICATIONS (CCA 2015), 601, 606, IEEE, 2015年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, This paper considers a maximum likelihood estimation problem for a quadrotor UAV under the existence of sensor delays. Since the state equation of the UAV is nonlinear, we propose an approximated method consisting of the following two steps. The first step is devoted to estimation of the past state based on the delayed output. We use an extended Kalman filter for this purpose. As the second step, an estimate of the present state is calculated by simulating the linear approximated system from the past to the present time. It is proved that the proposed method provides an approximated maximum likelihood estimation. The effectiveness of the estimator is verified by an experiment.

Higher-Order Sliding-Mode Control for Binary Input by Using Implicit Lyapunov Function
Ryo Nonaka, Yuh Yamashita, Daisuke Tsubakino
IFAC-PapersOnLine, 48, 11, 866, 871, Elsevier B.V., 2015年, ［査読有り］
英語, 研究論文（学術雑誌）, We propose a binary input controller for higher-order sliding-mode control. The proposed method extends the continuous controller for higher-order sliding-mode control to applicable for a system with a binary input constraint. Under the binary input constraint, the controller for the system can only use two input such as ±1. We design a binary input controller for the system based on the implicit Lyapunov function method. We also reduce the chattering phenomenon on the sliding hypersurface except on the origin. The reduction mechanism provides strong effect for the chattering reduction under three-valued input constraint ±1 and zero, which is demonstrated in the simulation in this paper.

State estimation for boundary-coupled parabolic distributed parameter systems using spatial averages
Daisuke Tsubakino, Yuh Yamashita
2015 10TH ASIAN CONTROL CONFERENCE (ASCC), IEEE, 2015年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, This paper proposes an indirect method for designing a Luenberger-type state observer for systems described by boundary-coupled two parabolic partial differential equations. In particular, we concentrate on the case where outputs are spatial averages of the state variables. The proposed method consists of two steps. We first introduce a state transformation that converts the system into another system with boundary measurement. Then, the backstepping approach can provide a state observer for the converted system. An estimate of the original state variables is constructed through the inverse transformation. The performance of the proposed observer is confirmed by a numerical simulation.

General Scheme for Design of Higher-Order Sliding-Mode Controller
Ryo Nonaka, Yuh Yamashita, Daisuke Tsubakino
2015 AMERICAN CONTROL CONFERENCE (ACC), 5176, 5181, IEEE, 2015年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, Higher-order sliding-mode control has exclusive properties, such as robustness against the disturbance and uncertainty. Moreover, the finite-time stability of a system can be realized with a homogeneous sliding-mode controller. However, designing a higher-order sliding-mode controller is difficult. In this paper, we introduce a general strategy that includes various types of homogeneous sliding-mode control laws. We can check the stability of a system under the control law with some explicit inequalities. Therefore, we can theoretically design the controller even if the target system has input constraints, bounded disturbances, and uncertainty.

Asymptotic stabilization of nonlinear systems on general manifolds via minimum projection method
Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani
2009 European Control Conference, ECC 2009, 2757, 2762, Institute of Electrical and Electronics Engineers Inc., 2014年03月26日
英語, 研究論文（国際会議プロシーディングス）, 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.

零次ホールダ下での離散時間近似と連続時間システム同定への応用
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
日本語, 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．

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

Homogeneous Stabilization of Driftless Input-Affine Systems Using Wiener Processes
Kenta Hoshino, Yuh Yamashita, Yuki Nishimura, Daisuke Tsubakino
2014 IEEE 53RD ANNUAL CONFERENCE ON DECISION AND CONTROL (CDC), 3167, 3172, IEEE, 2014年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, This paper presents a method for the homogeneous stabilization of homogeneous driftless input-affine systems using feedback controllers with Wiener processes. Although previous studies have shown methods for the stabilization of nonholonomic systems by using Wiener processes, the closed-loop systems sometimes show slow convergence. To improve the convergence rate, we show a method that gives a homogeneous controller by redesigning the controllers designed by the previous methods. By the virtue of the homogeneity, the closed-loop systems exhibit almost sure exponential stability with respect to homogeneous norms. A numerical example shows the effectiveness of the proposed method.

Collision-free Formation Control of Two-wheeled Vehicles based on Triangular LQ Optimal Regulator
Takashi Kusunoki, Daisuke Tsubakino, Yuh Yamashita
2014 IEEE CONFERENCE ON CONTROL APPLICATIONS (CCA), 1072, 1077, IEEE, 2014年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, This paper considers a formation control problem of two-wheeled vehicles. We first design a base controller based on the structured linear quadratic optimal regulator. The resulting optimal control gain is a lower triangular matrix; thus, agents communicate with each other in a top-down manner. However, vehicles may collide with each other under this control law since it is linear. To avoid collision of vehicles, we design a potential function by deforming the quadratic form of the stabilizing solution of the Riccati equation. The gradient of the potential function gives a control law that guarantees collision avoidance. The control law coincides with the optimal control law if vehicles are far from each other. The effectiveness of the proposed controller is confirmed by numerical simulation.

Boundary control of a cascade of two parabolic PDEs with different diffusion coefficients
Daisuke Tsubakino, Miroslav Krstic, Yuh Yamashita
Proc. 52nd IEEE Conf. Dec. & Cont., 3720, 3725, 2013年12月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

Stochastic Asymptotic Stabilizers for Deterministic Input-Affine Systems Based on Stochastic Control Lyapunov Functions
Yuki Nishimura, Kanya Tanaka, Yuji Wakasa, Yuh Yamashita
IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, E96A, 8, 1695, 1702, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, 2013年08月, ［査読有り］
英語, 研究論文（学術雑誌）, 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.

部分変換を用いた境界結合放物型分布定数系の境界制御
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］
日本語, 研究論文（学術雑誌）, This paper considers a boundary stabilization problem of systems described by boundary coupled two one-dimensional parabolic partial differential equations based on the backstepping method. Unlike the conventional backstepping framework, we propose a state transformation that contains the state of the unforced subsystem partially. It is proved that this transformation is well-defined and converts the original system into an exponentially stable system together with an associated state feedback control law under a condition that ensures the stability of the unforced subsystem. The original system with this control law inherits the stability of the transfomed one. The effectiveness of the obtained control law is demonstrated numerically.

Stochastic Extremum-Seeking Algorithm for One-Dimensional and Multivariate Static Systems
HOSHINO Kenta, YAMASHITA Yuh
SICE J Control Meas Syst Integr, 6, 3, 177, 185, The Society of Instrument and Control Engineers, 2013年05月, ［査読有り］
英語, The aim of this paper is to present a stochastic extremum-seeking algorithm for one-dimensional and multivariate optimization of static systems. Extremum-seeking algorithms estimate the optimum value of a function using perturbation signals. The authors propose three schemes (a basic scheme, an annealing parameter scheme, and a high-pass filter scheme) for the one-parameter problem and one scheme (a high-pass filter scheme) for the multivariate problem. These methods employ Wiener processes for the perturbation signals. In this paper, the proposed methods are shown to converge by means of a stability analysis of stochastic systems. The paper presents some numerical examples to demonstrate the effectiveness of the methods.

Simultaneous estimation of vehicle sideslip angle and tire-road friction coefficient
Momoko Yoshida, Yuh Yamashita
2013 PROCEEDINGS OF SICE ANNUAL CONFERENCE (SICE), 1586, 1591, IEEE, 2013年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, We simultaneously estimate the vehicle sideslip angle and tire-road friction coefficient from generally given information from various sensors by using the differences in tire characteristics. In most previous studies, a linear vehicle model for determining the lateral force has been used, whereas we use a nonlinear model. Furthermore, we use Levant's exact differentiator to determine the yaw angular acceleration from the yaw rate in real time. The proposed method can accurately estimate the vehicle sideslip angle and provide real-time information about road surface conditions without the need to use an expensive real-time kinematic global positioning system sensor.

Stability and Stabilization of Homogeneous Stochastic Systems
Kenta Hoshino, Yuh Yamashita, Yuki Nishimura, Daisuke Tsubakino
2013 IEEE 52ND ANNUAL CONFERENCE ON DECISION AND CONTROL (CDC), 1229, 1234, IEEE, 2013年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, This study considers homogeneous stochastic systems and shows their stability and stabilization. We define a homogeneous stochastic system as an extension of a homogeneous deterministic system. We show that homogeneous systems can exhibit exponential stability or finite-time stability according to the degree of homogeneity. Further, we show a control law for the stabilization of homogeneous stochastic control systems. Numerical examples of stable homogeneous systems and the stabilization of a homogeneous control system are also presented.

Control of two-wheeled mobile robot via homogeneous semiconcave control Lyapunov function
Shunsuke Kimura, Hisakazu Nakamura, Yuh Yamashita
IFAC Proceedings Volumes (IFAC-PapersOnline), 9, 1, 92, 97, 2013年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, Semiconcave control Lyapunov functions for globally asymptotic stabilizing controllable systems are available. However, a semiconcave control Lyapunov function for nonholonomic systems has not been proposed yet. For a two-wheeled mobile robot, we construct a homogeneous semiconcave control Lyapunov function and a control law with the function. The advantages of the proposed method are confirmed by computer simulation. © IFAC.

Constructive design method of stochastic continuous feedback laws for stabilization of deterministic nonlinear systems
Kenta Hoshino, Yuki Nishimura, Yuh Yamashita, Daisuke Tsubakino
2013 AMERICAN CONTROL CONFERENCE (ACC), 2013 Vol.8, 6424, 6429, IEEE, 2013年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, The purpose of this paper is to present a constructive design method of a stochastic feedback law for a deterministic nonlinear affine system. This design method gives a feedback law in the case that a randomized system is given as a Stratonovich-type stochastic differential equation, based on a result of Wong and Zakai. It is proved that a designed feedback law can globally asymptotically stabilize a randomized system with probability one. The design method employs a notion of a stochastic control Lyapunov function and the so-called Sontag's formula. The method in this paper aims the stabilization of nonholomic systems and non-Euclidean systems, which cannot be stabilized by any continuously differentiable time-invariant feedback laws. We can obtain a continuous feedback law for a state variable in the stabilization of such systems.

Stochastic asymptotic stabilizers for deterministic input-affine systems based on stochastic control lyapunov functions
Yûki Nishimura, Kanya Tanaka, Yuji Wakasa, Yuh Yamashita
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E96-A, 8, 1695, 1702, Institute of Electronics, Information and Communication, Engineers, IEICE, 2013年, ［査読有り］
英語, 研究論文（学術雑誌）, In this paper, a stochastic asymptotic stabilization method is proposed for deterministic input-affine control systems, which are randomized by including Gaussian white noises in control inputs. The sufficient condition is derived for the diffusion coefficients so that there exist stochastic control Lyapunov functions for the systems. To illustrate the usefulness of the sufficient condition, the authors propose the stochastic continuous feedback law, which makes the origin of the Brockett integrator become globally asymptotically stable in probability. Copyright © 2013 The Institute of Electronics, Information and Communication Engineers.

Stability and stabilization of homogeneous stochastic systems
Kenta Hoshino, Yuh Yamashita, Yûki Nishimura, Daisuke Tsubakino
Proceedings of the IEEE Conference on Decision and Control, 1229, 1234, Institute of Electrical and Electronics Engineers Inc., 2013年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, This study considers homogeneous stochastic systems and shows their stability and stabilization. We define a homogeneous stochastic system as an extension of a homogeneous deterministic system. We show that homogeneous systems can exhibit exponential stability or finite-time stability according to the degree of homogeneity. Further, we show a control law for the stabilization of homogeneous stochastic control systems. Numerical examples of stable homogeneous systems and the stabilization of a homogeneous control system are also presented. © 2013 IEEE.

Boundary control of a cascade of two parabolic PDEs with different diffusion coefficients
Daisuke Tsubakino, Miroslav Krstic, Yuh Yamashita
Proceedings of the IEEE Conference on Decision and Control, 3720, 3725, Institute of Electrical and Electronics Engineers Inc., 2013年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, 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.

連続時間系の制御リアプノフ関数に着目した1 サンプル遅れを持つディジタル制御
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］
日本語, 研究論文（学術雑誌）

二次元こう配的Morse-Smale力学系の散逸境界族の数値的算定
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］
日本語, 研究論文（学術雑誌）

Vibration suppression of mass-spring-damper system with dynamic dampers using IDA-PBC
Takashi Aoki, Yuh Yamashita, Daisuke Tsubakino
IFAC Proceedings Volumes (IFAC-PapersOnline), 45, 19, 42, 47, IFAC Secretariat, 2012年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, In this paper, we propose a vibration suppression control method for a mass-spring-damper system with one or two dynamic damper(s). The feedback is designed by the interconnection and damping assignment passivity-based control, where the system is transformed to a system having a skyhook damper with an artificial modification of the structure matrix. The feedback is expressed by a function of the relative displacements and velocities. The proposed control method can suppress the influences of the floor vibration and the disturbance force acting on the main body, simultaneously. © 2012 IFAC.

Navigation Function of Mobile Robots for Formation Driving
Masahiro Yamada, Yuh Yamashita, Daisuke Tsubakino
2012 IEEE INTERNATIONAL CONFERENCE ON CONTROL APPLICATIONS (CCA), 1590, 1595, IEEE, 2012年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, This paper investigates a vehicle formation control based on the following of a leader by nonholonomic mobile robots with two driving wheels. In this research, we propose a method for creating continuous and non-differentiable navigation functions, from which we derive a formation control law for each robot. The non-differentiability of the proposed navigation function removes the singularity encountered by conventional methods. The stability condition of a formation based on leader-following has been demonstrated by Tanner et al. as "Leader-to-Formation Stability" (LFS) [1]. In this paper, we assess the LFS property by regarding the navigation function as a LFS Lyapunov function.

Control Law for Multiple Obstacle Avoidance of Four-wheeled Vehicle with Limited Steering Angle by Multilayer Minimum Projection Method
Ryo Nonaka, Yuh Yamashita, Daisuke Tsubakino
2012 IEEE INTERNATIONAL CONFERENCE ON CONTROL APPLICATIONS (CCA), 1578, 1583, IEEE, 2012年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, Maintaining control of a mobile robot in a space punctuated by obstacles is known to be a difficult problem. It is generally necessary to avoid such obstacles and find as short a route as possible to a goal. In this paper, we approach such a problem by proposing a design method for a navigation function to a given goal point, assuming that we know the location and shape of the obstacles. We then obtain a control law for a four-wheeled vehicle from a control Lyapunov function extended from this navigation function. Four-wheeled vehicles, such as cars, cannot move sideways due to their nonholonomic constraint. The control law proposed in this paper clears the nonholonomicity and enables us to consider the direction of the vehicle and its steering angle limitation using the backstepping method with our navigation function. We also describe some experimental results of the proposed method for a small four-wheeled vehicle.

A Search Algorithm for Control Lyapunov Functions Using Radial Basis Function Networks
Takayuki Tsuzuki, Taiki Yagi, Kazunobu Yoshida, Yuh Yamashita
Proceedings of SICE Annual Conference 2011, 390, 394, 2011年09月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

Novel ODE-Type Smith Predictor for Nonlinear Control Systems with Delay
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］
英語, 研究論文（学術雑誌）, 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.

無限時間最適レギュレータ問題の近似解を構成するSchrödinger方程式について
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］
日本語, 研究論文（学術雑誌）, 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.

Static Nonsmooth Control Lyapunov Function Design via Dynamic Extension
Takahiro Yamazaki, Yuh Yamashita, Hisakazu Nakamura
2011 50TH IEEE CONFERENCE ON DECISION AND CONTROL AND EUROPEAN CONTROL CONFERENCE (CDC-ECC), 7573, 7578, IEEE, 2011年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, In this paper, we propose a method to obtain a control Lyapunov function (CLF) by the reduction of a CLF of an augmented system with a dynamic compensator. For asymptotically stabilizing control, dynamic compensators are not necessary in most of the cases. However, in some cases, we can easily design a stabilizing control law using a dynamic compensator. Therefore, a constructive design method using a static controller via a dynamic controller has advantages and is preferable in practice. In this paper, we assume that a CLF has been designed on an extended state space with a dynamic compensator, and show that taking minimum values of the CLF on the extended state space gives a nonsmooth CLF on the original state space. This method can be considered as an extension of the minimum projection method[1], [2]. We also show that the obtained CLF fulfills Lipschitz continuity and local semiconcavity if the original CLF on the extended state space is Lipschitz continuous and locally semiconcave. The effectiveness of the proposed method is demonstrated by an example.

Schrödinger equations for constructing infinite time horizon optimal regulators
Yuki Nishimura, Kanya Tanaka, Yuji Wakasa, Yuh Yamashita
IFAC Proceedings Volumes (IFAC-PapersOnline), 18, 1, 8058, 8063, 2011年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, In this paper, we propose a new method for constructing approximate value functions for nonlinear optimal regulator problems with infinite time horizons. We consider a canonical quantization, which is an operation to change classical mass systems to quantum mass systems. First, we apply the canonical quantization to mass systems equivalent to the optimal regulator systems. Second, we construct approximate optimal regulators by using the canonical quantized mass systems. Third, we clarify the conditions under which approximate solutions converge to the strict solutions. In addition, we demonstrate some examples with one-dimensional systems. © 2011 IFAC.

Passivity based control of bilateral teleoperators with time delay using low-pass filters
Naoyoshi Ohkawa, Yuh Yamashita
IFAC Proceedings Volumes (IFAC-PapersOnline), 18, 1, 3274, 3279, 2011年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, Bilateral teleoperators, designed within the passivity framework using the concepts of scattering transformation and two port network theory, provide robust stability in the constant delay condition in a network. In this paper, we propose a new coordination architecture for bilateral teleoperation in which static feedback gains in the master and slave robots are replaced by dynamic feedbacks using nonlinear low-pass filters. This architecture can select low-frequency gain and high-frequency gain independently. We can select the cut-off frequencies of the master block and slave block independently. We show the stability of our system and the ultimate boundedness of the position error between the master manipulator and the slave manipulator trajectories using a Lyapunov Krasovskii functional, in free motion with transmission time delay. This architecture guarantees accurate position tracking of the two robots in free motion with transmission time delay. Simulation results are presented that demonstrate the effectiveness of the proposed architecture for position and force tracking control. © 2011 IFAC.

Novel extremum seeking algorithm using Wiener process
Kenta Hoshino, Yuh Yamashita
2011 19th Mediterranean Conference on Control and Automation, MED 2011, 886, 891, 2011年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, We propose a new stochastic continuous time extremum seeking algorithm. The proposed algorithm is simpler to use than conventional stochastic continuous time extremum seeking algorithms. The proposed algorithm uses the Wiener process directly to extract gradients of objective functions. Three schemes, i.e., the simple scheme, the annealing parameter scheme, and the high-pass-filter scheme, are described. We develop a method for estimating the time evolution of the probability density of the solution of the system in the simple scheme. The stability analysis is discussed for the high-pass filter scheme. It is shown that the extreme value of the system is obtained with the proposed system in simulation results. © 2011 IEEE.

Novel ODE-type nonlinear Smith predictor for networked control systems with time-varying delay
Xuanxuan Teng, Yuh Yamashita
2011 19th Mediterranean Conference on Control and Automation, MED 2011, 19, 24, 2011年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, 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.

動的補償器による多様体上の非線形制御系の大域漸近安定化
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］
日本語, 研究論文（学術雑誌）, The purpose of this paper is to solve a global asymptotic stabilization problem for a nonlinear control system on a manifold with a complete metric. As well known, a system on a noncontractible manifold is not globally asymptotically stabilizable via a continuous feedback law. This problem results from the existence of multiple singular points of such a controlled system. It is shown that if all singular points can be assigned to a subspace of the extended state space using a dynamic compensator and a continuous feedback except for at most one jump, then the augmented system becomes globally asymptotically stable. Moreover, a method for stabilization is developed using a dynamic compensator and a global control Lyapunov function for an input-affine system. Finally, we propose a method for constructing the control Lyapunov function for a system such that the dimension of the coefficient matrix of the input is equal to the dimension of the state.

A sufficient condition for local semiconcavity of value function of nonlinear optimal regulator
Takayuki Tsuzuki, Yuh Yamashita
Proceedings of SICE Annual Conference 2010, 1559, 1562, 2010年08月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

Observer-Based Delayed Feedback Control Stabilizing Unstable Periodic Orbits of Continuous-Time Chaotic Systems
Yuh Yamashita
Proceeding of IFAC Workshop on Periodic Control Systems 2010, 75, 80, 2010年08月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

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

Novel ODE-type Nonlinear Smith Predictor for Networked Control Systems
Xuanxuan Teng, Yuh Yamashita
2010 IEEE INTERNATIONAL CONFERENCE ON CONTROL APPLICATIONS, 1773, 1778, IEEE, 2010年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, This paper discusses the stability analysis of networked control systems (NCSs) with transmission delays. In an NCS, the presence of time delays in the transmission may severely affect the performance of the closed-loop system and prevent the successful application of established nonlinear control methodologies. First, we present the backstepping interpretation of Smith predictors for linear time-variant systems in the state space. Second, we present a design and stability analysis for the control of a nonlinear Smith predictor and propose a new control scheme. The Smith predictor provides a set of future control predictions to make the closed-loop system achieve the desired control performance.

Minimum Projection Method for nonsmooth control Lyapunov function design on general manifolds
Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani
SYSTEMS & CONTROL LETTERS, 58, 10-11, 716, 723, ELSEVIER SCIENCE BV, 2009年10月, ［査読有り］
英語, 研究論文（学術雑誌）, Asymptotic stabilization on noncontractible manifolds is known as a difficult control problem. On the other hand, an important fact is every control system that is globally asymptotically stabilizable at a desired equilibrium must have nonsmooth control Lyapunov functions.
This paper considers the problem of construction of nonsmooth control Lyapunov functions on general manifolds, and we propose a nonsmooth control Lyapunov function design method called the 'Minimum Projection Method'. The proposed method considers a simple-structured smooth manifold associated with the original manifold by a surjective immersion, and then a control Lyapunov function defined on the simple-structured manifold is projected to the original manifold. A function on the original manifold is thus obtained.
In this paper, we prove that the control system on another manifold associated with a surjective immersion is determined uniquely, and the resulting function by the proposed method is a nonsmooth control Lyapunov function on the original manifold. The effectiveness of the proposed method is confirmed by examples. (C) 2009 Elsevier B.V. All rights reserved.

Homogeneous Stabilization for Input Affine Homogeneous Systems
Nami Nakamura, Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani
IEEE TRANSACTIONS ON AUTOMATIC CONTROL, 54, 9, 2271, 2275, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2009年09月, ［査読有り］
英語, 研究論文（学術雑誌）, Dilated homogeneous systems are local canonical forms of nonlinear control systems. For input affine homogeneous systems, existence of continuous homogeneous stabilizing controllers is equivalent to existence of differentiable homogeneous control Lyapunov functions. In this technical note, we propose an homogeneous stabilizing controller and an homogeneous inverse optimal controller for multi-input affine homogeneous systems with given homogeneous control Lyapunov functions.

Asymptotic stabilization of nonlinear systems on general manifolds via minimum projection method
Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani
Proceedings of European Control Conference 2009, 2757, 2762, 2009年08月, ［査読有り］
英語, 研究論文（学術雑誌）

Markov 過程の量子化を用いた確率的Lyapunov 関数の近似構築
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］
日本語, 研究論文（学術雑誌）, The existence of stochastic Lyapunov functions assures that the systems are stable in probability. However, general scheme of obtaining stochastic Lyapunov functions has not been introduced yet. This paper extends the authors' previous method[21] obtaining Lyapunov functions for deterministic cases to stochastic cases. In the method, difference-approximation scheme[6,10] and quantization of Markov processes[1,14] are used to approximate Lyapunov equations by linear quantum-like equations. We propose a method of obtaining approximate stochastic Lyapunov functions for nonlinear stochastic systems by superimposing the eigenfunctions of the quantum-like equations.

Construction method of Lyapunov functions based on eigen analysis
Yuki Nishimura, Yuh Yamashita, Kanya Tanaka, Yuji Wakasa
Proceedings of 2009 ICCAS-SICE, 691, 694, 2009年08月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

Stabilization Problems of Nonlinear Systems using Feedback laws with Wiener Processes
Yuki Nishimura, Kazuki Takehara, Yuh Yamashita, Kanya Tanaka, Yuji Wakasa
PROCEEDINGS OF THE 48TH IEEE CONFERENCE ON DECISION AND CONTROL, 2009 HELD JOINTLY WITH THE 2009 28TH CHINESE CONTROL CONFERENCE (CDC/CCC 2009), 7363, 7368, IEEE, 2009年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, This paper proposes a method to stabilize the origins of deterministic dynamical systems by state feedback control laws with Wiener processes. First, we obtain Ito-type stochastic dynamical systems by randomizing ordinary differential equation systems. Second, we design the diffusion coefficients. Then, we obtain Sontag-type global asymptotically stabilizers based on the stochastic control Lyapunov functions. Moreover, we show the usefulness of our results by some examples, i.e., systems with noncontractible state spaces and nonholonomic systems.

Homogeneous stabilization for input affine homogeneous systems
Nami Nakamura, Hisakazu Nakamura, Yuh Yamashita
IEEE Transactions on Automatic Control, 54, 9, 2271, 2275, IEEE, 2009年, ［査読有り］
英語, 研究論文（学術雑誌）, In this paper, we propose an homogeneous stabilizing controller for input-affine homogeneous systems. Moreover, we provide an homogeneous inverse optimal controller.

Global Asymptotical Stabilization of Morse-Smale Systems Using Weak Control-Lyapunov Functions
Gou NISHIDA, Takayuki TSUZUKI, Hisakazu NAKAMURA, Yuh YAMASHITA
SICE Journal of Control, Measurement, and System Integration, 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］
英語, 研究論文（学術雑誌）, This paper proposes a method of constructing weak control-Lyapunov functions for nonlinear systems by introducing a topological geometric assumption called a Morse-Smale system. A Lyapunov function is one of the most important tools to study stability and stabilization of nonlinear systems. However, a general way of finding Lyapunov functions has not been found yet. First, we confirm there is a weak Lyapunov function for Morse-Smale systems. Next, we define the escapability for singular structures of the weak Lyapunov function. If all singular structures are escapable, then the Morse-Smale system is a globally asymptotically stabilizable one. Finally, we present the method of constructing a set of weak control-Lyapunov functions to achieve global stabilization. The method is described in terms of a recursive sequence of singular structures. We call the sequence a weak Lyapunov filtration.

Stabilization problems of nonlinear systems using feedback laws with wiener processes
Yuki Nishimura, Kazuki Takehara, Yuh Yamashita, Kanya Tanaka, Yuji Wakasa
Proceedings of the IEEE Conference on Decision and Control, 7363, 7368, 2009年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, This paper proposes a method to stabilize the origins of deterministic dynamical systems by state feedback control laws with Wiener processes. First, we obtain Ito-type stochastic dynamical systems by randomizing ordinary differential equation systems. Second, we design the diffusion coefficients. Then, we obtain Sontag-type global asymptotically stabilizers based on the stochastic control Lyapunov functions. Moreover, we show the usefulness of our results by some examples, i.e., systems with noncontractible state spaces and nonholonomic systems. ©2009 IEEE.

Stochastic Lyapunov Function Design using Quantization of Markov Process
Proceedings of 47th IEEE Conference on Decision and Control, 3475, 3480, 2008年

Stabilization of Nonlinear Systems using Weak-Control-Lyapunov Functions
NISHIDA G.
Proceedings of 17th IFAC World Congress, 6190, 6195, 2008年

Global asymptotic stabilization for a nonlinear system on a manifold via a dynamic compensator　　　　　　　　　　　　　　　
Proceedings of 17th IFAC World Congress, 6178, 6183, 2008年

Lyapunov Function Design using Quantization of Markov Process
Yuki Nishimura, Yuh Yamashita
IFAC Proceedings Volumes, 41, 2, 2808, 2813, Elsevier BV, 2008年
英語, 研究論文（国際会議プロシーディングス）

Markov過程の量子化を用いたLyapunov関数の構築
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］
日本語, 研究論文（学術雑誌）

Inverse optimal control for nonlinear systems with input constraints
Nami Nakamura, Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani
Proceedings of 2007 European Control Conference, 5376, 5382, 2007年07月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

非線形系の大域漸近安定化を目的とした遺伝的プログラミングによる制御Lyapunov-Morse関数の探索
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］
日本語, 研究論文（学術雑誌）

Homogeneous eigenvalue analysis for complex homogeneous systems
Nami Nakamura, Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani
IFAC Proceedings Volumes (IFAC-PapersOnline), 7, 1, 107, 112, IFAC Secretariat, 2007年
英語, 研究論文（国際会議プロシーディングス）, In this paper, we analyze the stability of complex homogeneous systems by homogeneous eigenvalues. First, we redefine the complex homogeneity. Second, we obtain some properties of complex homogeneous functions, complex homogeneous vector fields, and complex homogeneous systems. Finally, we analyze the stability of complex homogeneous systems by homogeneous eigenvalues. Copyright © 2007 IFAC.

Homogeneous stabilization for input-affine homogeneous systems
Nami Nakamura, Hisakazu Nakamura, Yuh Yamashita
PROCEEDINGS OF THE 46TH IEEE CONFERENCE ON DECISION AND CONTROL, VOLS 1-14, 3770, +, IEEE, 2007年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, In this paper, we propose an homogeneous stabilizing controller for input-affine homogeneous systems. Moreover, we provide an homogeneous inverse optimal controller.

放物型分布定数系の適応オブザーバを用いた状態フィードバック安定化
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
This paper proposes a design method of stabilizing state feedback for distributed parameter systems of parabolic type with adaptive observers. The distributed parameter system with unknown coefficients is described by evolution equations in Hilbert space. The structure of adaptive observer using filtered values generated from input and output is stated. Moreover, control law using estimates of unknown coefficients is derived. Finally, by assuming the persistency of excitation, stability of the proposed control system is shown.

Optimal control of formation flight based on MLD systems
Miao Du, Yuh Yamashita
PROCEEDINGS OF THE 2007 IEEE CONFERENCE ON CONTROL APPLICATIONS, VOLS 1-3, 1292, 1297, IEEE, 2007年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, In this paper, formation flight is modeled as a mixed logical dynamical (MLD) system, which is described by linear equations subject to linear inequalities involving real and integer variables. This model is built by discretizing the continuous-time nonlinear kinematical equations of formation flight system through the Euler method, quantizing its physical input variables, and integrating operating constraints. The control objective is to maintain the relative positions and orientations between aircraft close to their desired values to keep a formation geometry without potential collisions despite the maneuvering of the leader. The resulting MLD system of formation flight can be governed by the mixed integer predictive control (MIPC) law, and the optimal predictive control input can be obtained by solving an equivalent mixed integer linear programming (MILP) problem. This MLD model essentially considers the three dimensional motion of aircraft. The effectiveness of this method is demonstrated by simulation results.

Homogeneous eigenvalue analysis for complex homogeneous systems of degree (l,l)
Nami Nakamura, Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani
PROCEEDINGS OF SICE ANNUAL CONFERENCE, VOLS 1-8, 1238, +, IEEE, 2007年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, In this paper, we analyze the stability of complex homogeneous systems of degree (l, l) by homogeneous eigenvalues. First, we define homogeneous eigenvalues and homogeneous eigenvectors for complex homogeneous systems of degree (l, l). Then, we obtain solutions on homogeneous eigenvectors. Convergence of the solutions depends not only on homogeneous eigenvalues but also on homogeneous eigenvectors. Moreover, solutions on homogeneous eigenvectors never vibrate. Hence, it may not be appropriate to assign complex analytic homogeneous systems to real analytic homogeneous systems in complex transformation.

Global asymptotic stabilization of nonlinear system with multiple singular points using changeover of control Lyapunov-Morse function
Kazuki Takeharai, Takayuki Tsuzuki, Yuh Yamashita
PROCEEDINGS OF SICE ANNUAL CONFERENCE, VOLS 1-8, 104, +, IEEE, 2007年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, 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

Semi-global output regulation of nonminimum-phase nonlinear systems via error feedback
Yoshinori Hirose, Yuh Yamashita
PROCEEDINGS OF SICE ANNUAL CONFERENCE, VOLS 1-8, 1259, +, IEEE, 2007年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, We consider semi-global output regulation of single-input single-output nonminimum-phase nonlinear systems via error feedback. Onishi et al. introduced the method like backsteppings to solve some global output regulation problems via state feedback in non-minimum phase nonlinear systems. Yang et al. introduced a comprehensible idea to achieve semi-global stabilization via output feedback. We use these ideas. The regulator has saturation to prevent that sudden observation noise make the state of the whole system escape from origin neighborhood. This method requires the solvabilities of some partial differential equations and a linear growth condition.

Homogeneous stabilization for input-affine homogeneous systems
Nami Nakamura, Hisakazu Nakamura, Yuh Yamashita
Proceedings of the IEEE Conference on Decision and Control, 80, 85, 2007年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, In this paper, we propose an homogeneous stabilizing controller for input-affine homogeneous systems. Moreover, we provide an homogeneous inverse optimal controller. © 2007 IEEE.

On characteristic families of dissipative boundaries for two-dimensional gradient-like Morse-Smale controlled systems
Ryuji Enomoto, Yukishige Izue, Yuh Yamashita
2007 INTERNATIONAL CONFERENCE ON CONTROL, AUTOMATION AND SYSTEMS, VOLS 1-6, 1487, +, IEEE, 2007年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, The method of gradient-like Morse-Smale controlled (GLMSC) systems is a systematic approach to solve global asymptotic stabilization problems for finite and nonlinear state equations. A GLMSC system is a closed loop system equipped with the structure of a gradient-like Morse-Smale flow. In general, the system has finitely many hyperbolic singular points of the vector field. Its global compact attractor can be represented as a normal CW-complex (CWC). For a fixed combination of hyperbolic singular points, there appear a vast number of corresponding CWCs with different structures. In this paper, we investigate an identification technique for these CWCs with the same singular point data and propose a notion of 'characteristic families of dissipative boundaries' for distinguishing a given CWC from others.

Searching for control Lyapunov-Morse functions using genetic programming for global asymptotic stabilization of nonlinear systems
Takayuki Tsuzuki, Kousuke Kuwada, Yuh Yamashita
Proceedings of the 45th IEEE Conference on Decision and Control, 5114, 5119, IEEE, 2006年12月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

Asymptotic Stability Analysis for Homogeneous Systems Using Homogeneous Eigenvalues
Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani
Proceedings of the 45th IEEE Conference on Decision and Control, 4230, 4235, IEEE, 2006年12月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

放物型分布定数系における適応オブザーバ
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］
日本語, 研究論文（学術雑誌）, 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.

同次固有値を用いた同次システムの解析
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］
日本語, 研究論文（学術雑誌）, This paper focuses on the problem of stability of homogeneous systems with dilation. First, we propose 'homogeneous eigenvalue' for the homogeneous systems. Next, we analyze stability of the homogeneous systems using the homogeneous eigenvalues, and we show that the positive homogeneous eigenvalues imply instability. Finally, we show effectiveness of the proposed method by examples.

Existence of Homogeneous Eigenvalues for Homogeneous Systems
Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani
17th International Symposium on Mathematical Theory of Networks and Systems, 2799, 2804, 2006年07月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

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］
英語, 研究論文（国際会議プロシーディングス）

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］
英語, 研究論文（国際会議プロシーディングス）

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］
英語, 研究論文（国際会議プロシーディングス）

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］
英語, 研究論文（国際会議プロシーディングス）

コンパス型２足ロボットモデルの姿勢安定解析
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］
日本語, 研究論文（学術雑誌）, This paper focuses on the problem of postural stability of a biped robot. We consider a compass-like biped model and analyze its postural stability based on the energy dissipation when the idling leg collides against the ground surface. We calculate the amount of energy dissipation by using rigid dynamics. We propose a novel criterion PSC (Postural Stability Criterion) that judges postural stability of the robot. Finally the effectiveness of the proposed criterion with two other indexes is demonstrated by computer simulation.

Stabilization of nonlinear planer systems using homogeneous eigenvalues
Hisakazu Nakamura, Gou Nishida, Hirokazu Nishitani, Yuh Yamashita
2006 SICE-ICASE INTERNATIONAL JOINT CONFERENCE, VOLS 1-13, 33, +, IEEE, 2006年
英語, 研究論文（国際会議プロシーディングス）, 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.

制御Lyapupov-Morse関数による大域漸近安定化
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
日本語, 研究論文（学術雑誌）, 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.

入力制約付き非線形システムに対する逆最適制御
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］
日本語, 研究論文（学術雑誌）

同次有限時間整定制御を用いた車両型移動ロボットの大域安定化制御
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．．

時系列解析を行った株価とボラティリティによるオプションプライシングについて
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。

Asymptotic stability of homogeneous systems using homogeneous eigenvalues
Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani
PROCEEDINGS OF THE 45TH IEEE CONFERENCE ON DECISION AND CONTROL, VOLS 1-14, 4234, +, IEEE, 2006年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, 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］
英語, 研究論文（国際会議プロシーディングス）

GLOBAL ASYMPTOTIC STABILIZATION BY USING THE CONTROL LYAPUNOV FUNCTION
Takayuki Tsuzuki, Yuh Yamashita, Ryuji Enomoto
IFAC Proceedings Volumes (Proc. IFAC World Congress 2005), 38, 1, 640, 645, Elsevier BV, 2005年07月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

On a topological condition for strongly asymptotically stable differential inclusions
Yuh Yamashita, Takayuki Tsuzuki, Hisakazu Nakamura
2005 44th IEEE Conference on Decision and Control & European Control Conference, Vols 1-8, 5444, 5449, IEEE, 2005年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, In this paper, we will show that a system on a non-contractible manifold cannot be strongly asymptotically stabilized in Filippov's sense, even if discontinuous feedback is used. The fact is well-known for C-1 feedback case, and we extend it to the discontinuous feedback case. To consider the stabilization problem on a non-contractible manifold, the assumption convexity or upper semicontinuity is restrictive. We will propose a new type of differential inclusion without upper semicontinuity by defining a function indicating a rate of leaving from discontinuous set. By adopting the new differential inclusion, stabilization problems on non-contractible manifolds become possible for many cases.

Grobal position and posture control of a two-wheeled mobile robot using a discontinuous homogeneous control
H Nakamura, T Kaji, H Nishitani, Y Yamashita
2005 IEEE INTERNATIONAL CONFERENCE ON CONTROL APPLICATIONS (CCA), VOLS 1AND 2, 1569, 1574, IEEE, 2005年
英語, 研究論文（国際会議プロシーディングス）, 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

Nonlinear continuous-time reference governors for constrained nonlinear systems　　　　　　　　　　　　　　　
16th IFAC World Congress (CD-ROM), Fr-M08-TO/6, 2005年

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

入力制約付き非線形システムに対する制御則設計
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
日本語

Homogeneous eigenvalue analysis of homogeneous systems
NAKAMURA H.
16th IFAC World Congress (CD-ROM), Mo-A11-TO/4, 2005年

多種の生理信号を用いた思考状態の推定
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］
日本語, 研究論文（学術雑誌）

非線形オブザｰバを用いた人工衛星の大域的漸近安定な姿勢制御系設計
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
日本語

Lyapunov functions for homogeneous differential inclusions
Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani
IFAC Proceedings Volumes (Part of special issue: 6th IFAC Symposium on Nonlinear Control Systems), 37, 13, 733, 738, Elsevier BV, 2004年09月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

Human modeling and simulation for plant operations
YH Jin, Y Yamashita, H Nishitani
COMPUTERS & CHEMICAL ENGINEERING, 28, 10, 1967, 1980, PERGAMON-ELSEVIER SCIENCE LTD, 2004年09月
英語, 研究論文（学術雑誌）, It is widely known that various types of human errors occur in the confused state of a plant operator's mind under abnormal situations. In order to understand the generation mechanism of these human errors in the circumstances of disturbances and equipment failures, we have developed a cognitive information-processing model incorporating the operator's physical and mental states. The operator model is installed on a PC and connected to a boiler plant simulator for training through a human-machine interface model that we also developed. Using this simulation environment we examine perceptual error in the monitoring mode and cognitive error in fault diagnosis during malfunctions. The simulation results coincide well qualitatively with observations of actual plant operations and simulator training. This operator model can be used to analyze the generation mechanism of various types of human errors from the viewpoint of cognitive information processing. Accordingly, we can study how to prevent human errors and evaluate the effects of various measures by running simulations. (C) 2004 Elsevier Ltd. All rights reserved.

Computer aids for knowledge management in plant operations
O Orapimpan, A Kurosaki, T Kurooka, Y Yamashita, H Nishitani
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, 43, 14, 3731, 3740, AMER CHEMICAL SOC, 2004年07月
英語, 研究論文（学術雑誌）, It is difficult to extract tacit knowledge in the workplace. In this paper, we apply video annotation to externalize the technologies and skills in plant operations. We have developed two prototype systems. The first is an interactive support system using multimedia, which offers functions for collecting "know-how" and "know-why" from on-site plant operations and for presenting this information as learning materials. The second is a system for evaluating emergency training results and for extracting common problems and lesson points. This system is useful for exploratory sequential data analysis of human behavior.

認知情報処理モデルを用いた異常診断におけるプラントオペレータの認知エラーの考察
金 銀花, 山下 裕, 西谷 紘一
ヒューマンファクターズ, 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
日本語

Controller design for a nonlinear system with inputs restricted to a direct product of Minkowski balls
N Kidane, H Nakamura, Y Yamashita, H Nishitani
2004 43RD IEEE CONFERENCE ON DECISION AND CONTROL (CDC), VOLS 1-5, 4069, 4074, IEEE, 2004年
英語, 研究論文（国際会議プロシーディングス）, In this paper, we propose a continuous controller for a nonlinear system such that the inputs are restricted to a direct product of Minkowski balls. We also demonstrate the effectiveness of the controller by computer simulation.

Inverse optimization for a nonlinear system with an input constraint
N Kidane, Y Yamashita, H Nakamura, H Nishitani
SICE 2004 ANNUAL CONFERENCE, VOLS 1-3, 1210, 1213, SOC INSTRUMENT CONTROL ENGINEERS JAPAN, 2004年
英語, 研究論文（国際会議プロシーディングス）, 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

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

Stabilization of a cascade-connected nonlinear system with an input constraint
H Nakamura, N Kidane, Y Yamashita, H Nishitani
SICE 2004 ANNUAL CONFERENCE, VOLS 1-3, 1874, 1879, SOC INSTRUMENT CONTROL ENGINEERS JAPAN, 2004年
英語, 研究論文（国際会議プロシーディングス）, 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.

非線形DAE系に対する制御系設計
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
In this paper, we propose a design method of an observer-based controller for nonlinear differential algebraic equation (DAE) systems. We transform a DAE system to an explicit ordinary differential equation (ODE) system that is restricted to an invariant manifold by differentiating the original DAE repeatedly. If the DAE is non-regular, we add integrators to inputs to avoid impulse modes. We design a state feedback law that incorporates redundant state variables and an observer that estimates all of these variables simultaneously. We also give a set of sufficient conditions for the global stability of the control system. The efficiency of the controller is demonstrated by computer simulation.

Developing a driving simulator and an assessment methodology to estimate a driver's mental state when distracted
Hiroaki Kosaka, Akira Kurosaki, Atsushi Harada, Yuh Yamashita, Hirokazu Nishitani
SAE Technical Papers, Paper Number: 2004-01-0233, 2004年
英語, 研究論文（国際会議プロシーディングス）, 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

プラントオペレータの異常診断過程のモデル化とシミュレーション
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］
日本語, 研究論文（学術雑誌）

Controller design for a nonlinear system with inputs restricted to a direct product of Minkowski balls
Nami Kidane, Hisakazu Nakamura, Yuh Yamashita, Hirokazu Nishitani
Proceedings of the IEEE Conference on Decision and Control, 4, 4069, 4074, Institute of Electrical and Electronics Engineers Inc., 2004年
英語, 研究論文（国際会議プロシーディングス）, 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.

チェインドシステムに対する同次有限時間整定制御
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
This paper focuses on the problem of stabilization of a chained-form nonholonomic system. We propose a time-invariant discontinuous finite-time homogeneous controller for the chained system. The controller has no singular point where the control inputs become infinite values. Using the characteristics of the homogeneous system, we can select the convergence speed of the controlled system. Namely, we can choose an exponentially stable system or a finite-time stable system. We designed the controller for a 3-state chained system and confirmed the superior performance of the controlled system by computer simulations.

Finite-time stabilization of the high-order chained system
H Nakamura, Y Yamashita, H Nishitani
PROCEEDINGS OF THE 2003 AMERICAN CONTROL CONFERENCE, VOLS 1-6, 4137, 4142, IEEE, 2003年
英語, 研究論文（国際会議プロシーディングス）, 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.

同次ディファレンシャル・インクルージョンに対するLyapunov関数
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
日本語

Observer Based I/O-linearizing Control of High Index DAE Systems　　　　　　　　　　　　　　　
2003 American Control Conference Proceedings, 3537, 3541, 2003年

Support systems for knowledge inheritance from video images of plant operations
O Orapimpan, T Kurooka, Y Yamashita, H Nishitani
PROCESS SYSTEMS ENGINEERING 2003, PTS A AND B, 15, 1466, 1471, ELSEVIER SCIENCE BV, 2003年
英語, 研究論文（国際会議プロシーディングス）, It is difficult to extract tacit knowledge in the workplace. In this paper, we apply video annotation to externalize the technologies and skills in plant operations. We developed two prototype systems. The first is an interactive support system using multimedia, which offers functions for collecting know-how and know-why in on-site plant operations, and for presenting this information as learning materials. The second is a system for evaluating emergency training results and extracting the common problems and lesson points. This system is useful for sequential data analysis related to human behavior.

Observer design for nonlinear systems described by differential-algebraic equations
Y Yamashita, N Kidane, H Nishitani
PROCESS SYSTEMS ENGINEERING 2003, PTS A AND B, 15, 1100, 1105, ELSEVIER SCIENCE BV, 2003年
英語, 研究論文（国際会議プロシーディングス）, We propose an observer design method for a differential-algebraic equation (DAE) systems with index one. In the observer, the algebraic equation constraint is fulfilled asymptotically. The error of the constraint converges to zero in finite time by means of functions that do not satisfy the local Lipschitz condition. The dynamics part of the observer is designed via the linear matrix inequality (LMI) technique. The observer is globally asymptotically stable under certain assumptions. Since the algebraic equations include input variable, the observer requires the derivative of input to plant. The derivative of the input is calculated from the controller states directly or estimated by the exact differentiator of Levant.

Modeling and simulation of human errors in plant operations
YH Jin, T Kurooka, Y Yamashita, H Nishitani
PROCESS SYSTEMS ENGINEERING 2003, PTS A AND B, 15, 1280, 1285, ELSEVIER SCIENCE BV, 2003年
英語, 研究論文（国際会議プロシーディングス）, We have developed a cognitive information processing model that incorporates the states of mind and body in order to simulate a plant operator's behavior under abnormal situations. This model enables simulation of human errors under various conditions. As an illustrative example, oversights in using two graphic panels designed for monitoring a boiler plant were examined. The results coincided qualitatively with observations of actual plant operations. This operator model can be used to analyze various types of human errors from the viewpoint of cognitive information processing and to study how to cope with different situations.

心理状態を考慮したオペレータモデルの開発
金 銀花, 黒岡 武俊, 山下 裕
日本プラント・ヒュ-マンファクタ-学会誌, 7, 2, 86, 96, 日本プラント・ヒュ-マンファクタ-学会, 2003年01月
日本語

Discontinuous control of nonholonomic systems using nondifferentiable Lyapunov functions
H Nakamura, Y Yamashita, H Nishitani, H Yamamoto
SICE 2003 ANNUAL CONFERENCE, VOLS 1-3, 1415, 1418, IEEE, 2003年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, This research focuses on the problem of discontinuous controller design by using a non-differentiable Lyapunov function. We propose a new concept for a solution of the discontinuous system. We design a discontinuous controller for a nonholonomic system by using a non-differentiable Lyapunov function and analyze the stability of the controlled system by using the proposed solution. Moreover, we confirm the performance of the controlled system by computer simulation.

Stabilizability analysis and controller design for a nonlinear system with an input constraint
N Kidane, H Nakamura, Y Yamashita, H Nishitani
SICE 2003 ANNUAL CONFERENCE, VOLS 1-3, 1419, 1422, IEEE, 2003年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, 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］
英語, 研究論文（国際会議プロシーディングス）

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］
英語, 研究論文（国際会議プロシーディングス）

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］
英語, 研究論文（国際会議プロシーディングス）

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］
英語, 研究論文（国際会議プロシーディングス）

非線形Receding-Horizon制御のための実時間最適化手法
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］
日本語, 研究論文（学術雑誌）, 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］
英語, 研究論文（国際会議プロシーディングス）

シミュレータトレーニング収録ビデオからの知識の創出
Orapimpan Opat, 黒岡 武俊, 山下 裕
日本プラント・ヒュ-マンファクタ-学会誌, 7, 1, 10, 19, 日本プラント・ヒュ-マンファクタ-学会, 2002年07月
日本語

相対次数が定義できない非線形系の追従制御
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
日本語, In this paper, we propose a new method of exact tracking control for multi-input multi-output nonlinear systems in which the relative degree for an output is not well defined at the origin. First, the system is transformed into a singularly perturbed system using a time-scale transformation and coordinate transformations. A composite control law is adopted to attain exact tracking control for the singularly perturbed system. However, it is difficult to solve simultaneous partial differential equations for the composite control law. We obtain an approximate solution of the PDEs via the ε-correction method. The proposed tracking control law is applied to the ball and plate system, which is a typical example having no relative degree at the origin.

Output regulation through singularities via state-feedback
Y Yamashita
NONLINEAR CONTROL SYSTEMS 2001, VOLS 1-3, 633, 638, PERGAMON-ELSEVIER SCIENCE LTD, 2002年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, In this paper, the problem of global output regulation using state-feedback is solved for nonlinear systems with no relative degree. We introduce an invariant manifold on which tracking error tends to zero, and through which we derive a coordinate transformation of state. The variable-gain feedback on the new coordinate attains global output regulation through singularities. Copyright (C) 2001 IFAC.

状態フィードバックを用いた非線形非最小位相系に対する大域的出力レギュレーション
大西 規雄, 山下 裕, 西谷 紘一
システム制御情報学会論文誌, 15, 1, 336, 343, 2002年01月, ［査読有り］
日本語, 研究論文（学術雑誌）

I/O-Linearizing controller and observer for Nonlinear DAE systems with high index
N Kidane, Y Yamashita, H Nishitani
SICE 2002: PROCEEDINGS OF THE 41ST SICE ANNUAL CONFERENCE, VOLS 1-5, 1966, 1969, IEEE, 2002年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, We consider I/O-linearization problems for differential algebraic equation (DAE) systems with high index using dynamic output feedback. First, a way to transform a DAE system to an explicit ordinary differential equation system is shown. Second, a design method is presented to achieve I/O-linearization by a static feedback law. Lastly, an observer is proposed to stabilize globally the controled system.

Smooth Lyapunov functions for homogeneous differential inclusions
H Nakamura, Y Yamashita, H Nishitani
SICE 2002: PROCEEDINGS OF THE 41ST SICE ANNUAL CONFERENCE, VOLS 1-5, 1974, 1979, IEEE, 2002年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, This paper provides a construction method of a smooth homogeneous Lyapunov function associated with a discontinuous homogeneous system, which is locally asymptotically stable. First, we analyze two similar converse Lyapunov theorems for differential inclusions and unify them into a simple theorem. Next, we propose a new definition of homogeneous differential inclusion. Then, we construct a smooth homogeneous Lyapunov function associated with the homogeneous differential inclusion. Lastly, we show that the order of homogeneity of a homogeneous system indicates the speed of convergence.

Compensation for transmission delay in remote-control system under measurement noise
Y Sawamura, Y Yamashita, H Nishitani
SICE 2002: PROCEEDINGS OF THE 41ST SICE ANNUAL CONFERENCE, VOLS 1-5, 219, 222, IEEE, 2002年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, In digital tele-communication, the delay time of the transmission isn't fixed. One solution is to design a new digital controller which is composed of an analog controller and two digital compensators. However, this system is weak to measurement noise. We develop a new digital controller that can cope with the problems of measurement noise by applying the H-infinity control method.

Global asymptotic stabilization of nonminimum phase nonlinear systems via extended backstepping
N Onishi, Y Yamashita, H Nishitani
SICE 2002: PROCEEDINGS OF THE 41ST SICE ANNUAL CONFERENCE, VOLS 1-5, 2249, 2254, IEEE, 2002年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, In this paper, we address the problem of global asymptotic stabilization for a single-input single-output non-linear system that may not be minimum phase. To solve this problem, we introduce a set of invariant manifolds which have hierarchical structure. We transform the plant repeatedly by using this set of invariant manifolds. Under the linear growth condition and some additional assumptions, global asymptotic stabilization is achieved by applying a variable-gain state feedback law to the obtained system.

Discontinuous finite-time control of multi-generator nonholonomic systems
H Nakamura, Y Yamashita, H Nishitani
SICE 2002: PROCEEDINGS OF THE 41ST SICE ANNUAL CONFERENCE, VOLS 1-5, 1980, 1983, IEEE, 2002年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, 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］
英語, 研究論文（学術雑誌）

Real-time monitoring of a plant operator's thinking state
T Kurooka, M Yamakawa, Y Yamashita, H Nishitani
JOURNAL OF CHEMICAL ENGINEERING OF JAPAN, 34, 11, 1387, 1395, SOC CHEMICAL ENG JAPAN, 2001年11月, ［査読有り］
英語, 研究論文（学術雑誌）, 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］
英語, 研究論文（国際会議プロシーディングス）

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］
英語, 研究論文（国際会議プロシーディングス）

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］
英語, 研究論文（国際会議プロシーディングス）

Development of a Learning System of Know-How and Know-Why in On-site Plant Operations
Opat Orapimpan, Kouichi Sakata, Taketoshi Kurooka, Yuh Yamashita, Hirokazu Nishitani
日本プラント・ヒューマンファクター学会誌, 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］
日本語, 研究論文（学術雑誌）

A real-time thinking state monitoring system for plant operation
T Kurooka, M Yamakawa, Y Yamashita, H Nishitani
HUMAN-COMPUTER INTERACTION - INTERACT'01, 609, 616, I O S PRESS, 2001年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, We have developed a real-time thinking state monitoring (RTSM) system for plant operation. First, the conception of plant operation with RTSM is proposed. Second, an estimation method of an operator's thinking state is reviewed. A nonlinear neural-network (NN) model and a linear regression model are applied as the estimation model. Third, the estimation method is experimentally evaluated by off-line analysis. It is confirmed that the NN model has some advantages. Finally, a prototype RTSM system with the NN model is developed and experimentally evaluated. The effectiveness is shown using mathematics problem solving.

Global output regulation of nonminimum phase nonlinear systems
N Onishi, Y Yamashita, H Nishitani
PROCEEDINGS OF THE 40TH IEEE CONFERENCE ON DECISION AND CONTROL, VOLS 1-5, 79, 84, IEEE, 2001年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, 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.

非線形DAE系に対する入出力線形化とオブザーバ
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
日本語

三輪移動体の最適制御問題と障害物回避問題に対する粘性解の数値解法
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］
日本語, 研究論文（学術雑誌）, To construct an optimal regulator for a wheeled vehicle, we need a viscosity solution of the Hamilton-Jacobi partial differential equation (HJ-PDE). In this paper, we propose a new method to have the viscosity solution of the HJ-PDE more quickly by applying a new searching method which uses a sequence of random inputs. This method reduces the number of searching points and makes calculation time faster than the previous method. Next, we propose a method to have the viscosity solution for obstacle avoidance. From the theoretical result of optimal control with state constraints, we can get the viscosity solution which avoids obstacles optimally. Then we make sure that an optimal solution can be obtained analytically by the finite difference numerical approximation of the HJ-PDE. This new result gives us an optimal solution without searching. Finally, the effectiveness of control results calculated from proposed methods are confirmed through simulations.

視線分析を用いたプラントオペレータの挙動の分析
山本 純平, 黒岡 武俊, 山下 裕
日本プラント・ヒューマンファクター学会誌, 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
日本語

高速探索手法によるCSTRの自励振動反応を利用した収率のオンライン最適化
今福 啓, 山下 裕, 西谷 紘一
化学工学論文集, 26, 5, 683, 686, 2000年09月, ［査読有り］
日本語, 研究論文（学術雑誌）

Design and verification of the SFC program for sequential Control
K Fujino, K Imafuku, Y Yamashita, H Nishitani
COMPUTERS & CHEMICAL ENGINEERING, 24, 2-7, 303, 308, PERGAMON-ELSEVIER SCIENCE LTD, 2000年07月, ［査読有り］
英語, 研究論文（学術雑誌）, A programmable controller (PC) programming technique using SFC (sequential function chart) has been adopted in sequential control system design because SFC can graphically represent the sequence how of control logic. However, when we design an SFC program, we must verify the program with the design specifications. For this purpose, we can use scenario simulation and exhaustive simulation. In this paper, we propose to model both the controlled object and the SFC program by a Petri net for verification by both types of simulations. (C) 2000 Elsevier Science Ltd. All rights reserved.

Mind state estimation for operator support
T Kurooka, Y Yamashita, H Nishitani
COMPUTERS & CHEMICAL ENGINEERING, 24, 2-7, 551, 556, PERGAMON-ELSEVIER SCIENCE LTD, 2000年07月, ［査読有り］
英語, 研究論文（学術雑誌）, We have developed a method to estimate a plant operator's thinking state during abnormal situations. The operator's thinking state is estimated from EEG data. First, three basic modes were defined according to the typical thinking slate of a plant operator at the time of a malfunction. Second, experiments were performed to evoke the basic modes. Third, a nonlinear model was developed to estimate the thinking state of a plant operator. Finally, the estimation method was applied to a subject who operated a boiler plant simulator under abnormal circumstances. It was verified that the method gives useful information for estimating the plant operator's thinking state. (C) 2000 Elsevier Science Ltd. All rights reserved.

Dynamic simulation and nonlinear control system design of a heterogeneous azeotropic distillation column
T Kurooka, Y Yamashita, H Nishitani, Y Hashimoto, M Yoshida, M Numata
COMPUTERS & CHEMICAL ENGINEERING, 24, 2-7, 887, 892, PERGAMON-ELSEVIER SCIENCE LTD, 2000年07月, ［査読有り］
英語, 研究論文（学術雑誌）, 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
英語, 研究論文（学術雑誌）, 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.

厳密入出力線形化を用いた蒸留塔の多変数制御
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］
英語, 研究論文（学術雑誌）, Exact input-output linearization, which is one method of nonlinear control, was applied to multivariable control of a distillation column. First, a four-input four-output system was transformed to four SISO systems by input-output linearization based on a simplified model of the distillation column. For this purpose, an appropriate set of outputs must be selected. Second, a control system was designed for the linearized four SISO systems, considering the influence of model mismatch. Finally, the performances of the control system were evaluated with simulation of a methanol-water distillation column. The simulation model was much more rigorous than the simplified one used for controller design. From the various viewpoints, such as the speed of response, recovery of the materials, and energy efficiency, the control system by input-output linearization showed better performance than the conventional multiloop control system. These characteristics were clearly noticed under large scaled disturbances. input-output linearization, distillation column, multivariable control, nonlinear control, process control. © 2000, The Society of Chemical Engineers, Japan. All rights reserved.

Global output regulation through singularities
Y Yamashita, A Isidori
PROCEEDINGS OF THE 39TH IEEE CONFERENCE ON DECISION AND CONTROL, VOLS 1-5, 1295, 1300, IEEE, 2000年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, 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］
英語, 研究論文（国際会議プロシーディングス）

Mind State Estimation in Logical Thinking Jobs
Taketoshi Kurooka, Yuh Yamashita, Hirokazu Nishitani
IEEE International Conference on Systems, Man, and Cybernetics, 407, 412, 1999年10月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

複数仕様を満たす制御系設計法の吸収冷凍機への応用
大形 明弘, 山下 裕, 西谷 紘一
化学工学論文集, 25, 5, 721, 727, 1999年09月, ［査読有り］
日本語, 研究論文（学術雑誌）

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］
英語, 研究論文（国際会議プロシーディングス）

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］
英語, 研究論文（国際会議プロシーディングス）

Hamilton-Jacobi偏微分方程式の粘性解を用いた三輪移動体の制御
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］
日本語, 研究論文（学術雑誌）, To construct an optimal regulator for nonlinear systems, we need to solve a Hamilton-Jacobi partial differential equation (HJ-PDE) . However, if the system has nonholonomic constraints, the HJ-PDE has a nonsmooth solution because of the nonsmoothness of the optimal cost function. In such a case, the viscosity solution, a nonsmooth weak solution of the HJ-PDE, is obtained.
In this paper, we deal with a wheeled vehicle, which is a nonholonomic system, and propose a numerical method to achieve a viscosity solution of the HJ-PDE using the dynamic programming principle (DPP) . The DPP can be applied to acquire a nonsmooth solution of the HJ-PDE. We also construct an optimal control law using derivatives of the viscosity solution of the HJ-PDE. The effectiveness of the proposed method is shown through simulations.

Estimation of Plant Operator's Thinking State using EEGs
Taketoshi Kurooka, Yuh Yamashita, Hirokazu Nishitani
The 15th World Congress of International Measurement Confederation (CD-ROM), Paper ID: 18.2.3, 412, 1999年06月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

複数の制御仕様を満たす定数状態フィードバックゲイン行列を求めるための1つの方法
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
日本語

Application of mind state estimation to plant operators
T Kurooka, M Kisa, Y Yamashita, H Nishitani
ANALYSIS, DESIGN AND EVALUATION OF MAN-MACHINE SYSTEMS 1998, 479, 484, ELSEVIER SCIENCE BV, 1999年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, 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.

非線形非標準H_∞制御問題
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
日本語, Sufficient conditions of the nonstandard nonlinear H_∞ control problem are provided. This problem needs not to satisfy the rank condition of the direct-through matrices from the controlled input to the regulated output and from the disturbance to the measured output. First, we present a feedback law via state feedback. Next, a feedback law via output feedback and an observer gain are given. It is shown by extending the result of the linear system to the nonlinear system.

脳波を用いたプラントオペレ-タの思考状態推定
黒岡 武俊, 木佐 昌文, 山下 裕
日本プラント・ヒュ-マンファクタ-学会誌, 3, 2, 100, 109, 日本プラント・ヒュ-マンファクタ-学会, 1998年10月
日本語

Hamilton-Jacobi偏微分方程式の一解法
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
日本語, 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］
英語, 研究論文（学術雑誌）

LMIを用いた吸収冷凍器の制御系設計
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］
英語, 研究論文（学術雑誌）, An absorption heat pump system is a complex nonlinear system. The system dynamics varies considerably depending on the load. The local linearization technique is not suitable for such a system, because a linearized model approximates the original nonlinear system only in the neighborhood of the point where linearization is done. In this paper, the dynamics of an absorption heat pump system is modeled as a linear time-varying system, of which the system matrix is within a specified polytope at any time. Once a plant is modeled as a polytope system, a controller design problem can be reduced to a convex programming problem which can be solved easily. Numerical simulations illustrate that this procedure is practical and effective to design a load following controller for the absorption heat pump system. © 1998, The Society of Chemical Engineers, Japan. All rights reserved.

Tracking control for unlinearizable nonlinear systems
Y Yamashita, T Bono, M Shima, H Nishitani
NONLINEAR CONTROL SYSTEMS DESIGN 1998, VOLS 1& 2, 195, 200, PERGAMON PRESS LTD, 1998年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, In this paper, we consider a tracking problem for nonlinear systems of which input-output behaviors cannot be linearized. Such a system is converted to a singularly perturbed control system using a time-scale transformation and coordinate transformations under some assumptions The exact-tracking control for the singularly perturbed control system is accomplished by a composite control law. The exact-tracking control law is approximated by truncating higher-order terms with respect to epsilon. The proposed method is applied to a ball and beam example. Copyright (C) 1998 IFAC.

Numerical computational method using genetic algorithm for the optimal control problem with terminal constraints and free parameters
Y Yamashita, M Shima
NONLINEAR ANALYSIS-THEORY METHODS & APPLICATIONS, 30, 4, 2285, 2290, PERGAMON-ELSEVIER SCIENCE LTD, 1997年12月, ［査読有り］
英語, 研究論文（学術雑誌）

Invariance condition of general nonlinear control system with integral type output
M Shima, Y Yamashita
NONLINEAR ANALYSIS-THEORY METHODS & APPLICATIONS, 30, 4, 2279, 2284, PERGAMON-ELSEVIER SCIENCE LTD, 1997年12月, ［査読有り］
英語, 研究論文（学術雑誌）

プラント運転を行うオペレータモデルの開発
北島 禎二, 中山 慶彦, 黒岡 武俊, 山下 裕, 西谷 紘一
本プラント・ヒューマンファクター学会誌, 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］
日本語, 研究論文（学術雑誌）

プラントオペレーションにおけるヒューマンモデリング
中山 慶彦, 北島 禎二, 山下 裕, 西谷 紘一
化学工学, 61, 8, 612, 613, 化学工学会, 1997年08月05日
日本語

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］
英語, 研究論文（国際会議プロシーディングス）

遺伝的アルゴリズムによる終端拘束付き最適制御問題の数値解法
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
日本語, In this paper, a new numerical computation method using genetic algorithm for an optimal control problem with terminal constraints and singular arcs is proposed. The input functions are parameterized using spline interpolation, which has devices that can represent discontinuous input functions. In order to treat the terminal constraints properly, Lagrange multipliers that are contained in genetic information of chromosomes are introduced. On the singular arcs, coefficients of inputs in Hamiltonian vanish, so the coefficients on the arcs are included in the extended performance index. The weight constants of the extended performance index are changed adaptively at every generation of the genetic algorithm. A simple example is solved using this method, which verifies the efficiency of genetic algorithm in the computation of the optimal control.

Robust control of an absorption heat pump system
A Ohgata, Y Yamashita, H Nishitani
COMPUTERS & CHEMICAL ENGINEERING, 21, Supplement 1, S131, S136, PERGAMON-ELSEVIER SCIENCE LTD, 1997年, ［査読有り］
英語, 研究論文（学術雑誌）, An absorption heat pump system is a complex nonlinear system. We proposed a practical procedure of controller design based on the idea of global linearization. Numerical simulation runs have illustrated this procedure is practical and effective for the complex nonlinear system.

Tracking control using self-organizing neural network
Y Yamashita, Y Ikuno, M Shima
PROCEEDINGS OF THE 35TH IEEE CONFERENCE ON DECISION AND CONTROL, VOLS 1-4, 3804, 3809, I E E E, 1996年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）, 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.

線形時変系に対する適応多段型学習制御
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］
日本語, 研究論文（学術雑誌）, In this paper, the adaptive multi-step learning control for continuous-time linear system is studied. Input function u_k+1 (t) is calculated from the triplets (u_k, e_k, e_k) and (u_k-1, e_k-1, e_k-1) where e_k is tracking error of k-th trial. The weighting coefficients of the triplets are determined adaptively. The convergence of the control law is proved by means of evaluation of the norm of tracking error. Moreover, the learning control is applied to the tracking problem of two-link robot manipulator.

CMACによる非線形離散時間系のモデル追従制御
山下 裕, 佐藤 友彦, 島 公脩
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］
日本語, 研究論文（学術雑誌）, 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.

一般的な連続時間・離散時間非線形系におけるInvarianceの条件と無干渉化
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］
日本語, 研究論文（学術雑誌）, In our previous paper 4) -12), we have studied "Theory of Invariance" for nonlinear continuous-time systems with their inputs appearing linearly. The aim of this paper is to derive necessary and sufficient conditions that inputs never effect outputs (so called conditions of "Invariance") for nonlinear discrete-time and continuous-time systems without the assumption of linearity in inputs. Applying these conditions to the decoupling problem, we obtained necessary and sufficient conditions which yield decoupling control laws for both the continuous-time systems and the discrete-time systems. The conditions of decoupling given by van der Schaft 13) and Grizzle 14) via geometric approach are different in forms from ours. But, it seems difficult to derive control laws from their conditions because the integration of partial deferential equations is needed there.

一般的な非線形系における入出力線形化
山下 裕, 島 公脩
計測自動制御学会論文集, 26, 9, p1009, 1014, 計測自動制御学会, 1990年09月
日本語

4元数による表現を用いた飛行体の大角度姿勢制御
細川 民樹, 山下 裕, 島 公脩
計測自動制御学会論文集, 26, 4, p467, 473, 計測自動制御学会, 1990年04月
日本語

Invarianceの理論とその応用 ― X.ブロック無干渉化
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］
日本語, 研究論文（学術雑誌）, In this paper, we study the block decoupling problem of nonlinear systems with C^ω-Structures : x=f (x) +G (x) u, y=h (x). Inputs and outputs are divided into N blocks, respectively. First, we propose a new algorithm by which we can determine the maximal locally controlled invariant distribution contained in Ker dh. This algorithm is an extension of nonlinear structure algorithm extensively used in the input-output linearlization, and can be applied to systems which is not input-output linearlizable. Moreover, it has an advantage in that we need not integrate the distribution.
Application of this algorithm to I-th output block yields a vector valued function z_I(x).Then, the block decoupling problem is solvable if and only if each row of D(G)z_I(x) is zero vector or is linearly independent of rows of other D(G)z_J(x)(J=1, …, N; I≠J). The state feedback control law which accomplishes the block decoupling is derived from z_I(x).

Invarianceの理論とその応用-9-多入力多出力非線形系の出力可制御性
山下 裕, 島 公脩
システムと制御, 31, 6, p450, 456, 日本自動制御協会, 1987年06月
日本語

非線形制御の何がまだできていないのか
山下 裕, 計測と制御, 60, 1, 339, 344, 2021年05月, ［招待有り］, ［筆頭著者］
日本語, 記事・総説・解説・論説等（学術雑誌）

通信遅延を含むネットワーク上の分散制御系における状態推定
足立 亮介, 山下 裕, 小林 孝一, システム制御情報学会研究発表講演会講演論文集, 61, 6p, 2017年05月23日
システム制御情報学会, 日本語

分散型イベント駆動条件をもつネットワーク化制御システムの非同期制御 (高信頼制御通信)
中島 共平, 小林 孝一, 山下 裕, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 116, 433, 31, 34, 2017年01月27日
電子情報通信学会, 日本語

モデル予測型デマンドレスポンスの価値評価
宮崎 公大, 小林 孝一, 東 俊一, 山口 順之, 山下 裕, 自動制御連合講演会講演論文集, 60, 344, 347, 2017年
自動制御連合講演会, 日本語

センサ・アクチュエータネットワークの制御入力と経路の同時最適化
佐藤 大, 小林 孝一, 山下 裕, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 116, 338, 89, 93, 2016年12月01日
電子情報通信学会, 英語

離散時間線形システムの分散型イベント駆動準最適制御 (高信頼制御通信)
中島 共平, 小林 孝一, 山下 裕, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 115, 442, 13, 16, 2016年01月29日
電子情報通信学会, 日本語

集合値で表される上位制御則に対するバックステッピング
鈴木 大基, 山下 裕, 椿野 大輔, システム制御情報学会研究発表講演会講演論文集, 59, 4p, 2015年05月20日
システム制御情報学会, 日本語

LQ最適レギュレータに基づくフォーメーション制御における衝突回避
楠木 孝, 椿野 大輔, 山下 裕, システム制御情報学会研究発表講演会講演論文集, 58, 5p, 2014年05月21日
システム制御情報学会, 日本語

基本的なグラフのラプラス行列を要素にもつ代数について
庄司 恵, 椿野 大輔, 山下 裕, システム制御情報学会研究発表講演会講演論文集, 58, 5p, 2014年05月21日
システム制御情報学会, 日本語

三角構造を保存したLQ最適レギュレータに基づくフォーメーション制御
楠木 孝, 椿野 大輔, 山下 裕, システム制御情報学会研究発表講演会講演論文集, 57, 5p, 2013年05月15日
システム制御情報学会, 日本語

二次元こう配的 Morse-Smale 力学系の散逸境界族の数値的算定
出江 幸重, 榎本 隆二, 山下 裕, 電子情報通信学会論文誌. A, 基礎・境界 = The transactions of the Institute of Electronics, Information and Communication Engineers. A, 95, 3, 261, 267, 2012年03月01日
本研究では,大城コンパクトアトラクタをもつような任意に与えられた二次元こう配的Morse-Smale力学系のリヤプノフ関数を求めることを最終目的としている.我々は,これまでに位相幾何学的な手法を利用して正則散逸境界を数値的に算定するアルゴリズムを示した.本論文では,二次元こう配的Morse-Smale力学系の特異散逸境界を含む散逸境界族の数値データを求めるためのアルゴリズムを提案し,その有効性を数値例を用いて示す., 一般社団法人電子情報通信学会, 日本語

支部の活動
渡辺 桂吾, 山下 裕, 曽根 秀昭, 寺嶋 一彦, 大薮 多可志, 黒江 康明, 谷口 隆雄, 岡 宏一, 石飛 光章, 計測と制御 = Journal of the Society of Instrument and Control Engineers, 50, 8, 570, 577, 2011年08月10日
日本語

未知負荷に対する分散協調制御
山下 裕, 電子情報通信学会技術研究報告. NLP, 非線形問題, 108, 276, 65, 70, 2008年10月30日
本報告では,移動ロボットによる被覆問題において,未知の外乱に対しその影響をキャンセルし,さらに各移動ロボットの制御負荷が平均化されるようにロボットが自律的に移動する手法を示す.Cortes el al.(2004)の論文と異なり,なすべき仕事が静的に既知関数として与えられているわけではなく,未知外乱によってなすべき仕事が動的に増加するモデルを考えている.各移動ロボットの制御則は受動性の理論により導かれ,局所的な情報のみから構成されている.シミュレーションにより,本手法の有効性および問題点を明らかにした., 一般社団法人電子情報通信学会, 日本語

不連続制御系の解と大域漸近安定化問題
都築 卓有規, 山下 裕, システム/制御/情報 : システム制御情報学会誌 = Systems, control and information, 52, 3, 84, 89, 2008年03月15日
システム制御情報学会, 日本語

Markov過程の量子化を用いた確率的Lyapunov関数の構築—Stochastic Lyapunov function design using quantization of Markov process—非線形問題
西村 悠樹, 山下 裕, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 107, 399, 47, 52, 2007年12月19日
東京 : 電子情報通信学会, 日本語

ある不連続制御系のロバスト性解析
都築 卓有規, 山下 裕, 電子情報通信学会技術研究報告. NLP, 非線形問題, 107, 399, 43, 46, 2007年12月12日
状態空間が線形空間と同相とは限らない多様体上の制御系の大域漸近安定化法として,原点以外に臨界点をもつ一般化制御Lyapunov関数を用いたものが提案されている.この方法では,入力アファインな制御則の不連続面上に不安定平衡点を配置することで,大域漸近安定化を実現している.本研究ではより一般的な非線形制御系について,一般化制御Lyapunov関数の存在性から,不連続な大域漸近安定化制御則の存在を示し,さらに加法的外乱に対するロバスト性を解析する., 一般社団法人電子情報通信学会, 日本語

非線形系の出力レギュレーション問題
山下 裕, 計測と制御 = Journal of the Society of Instrument and Control Engineers, 42, 10, 821, 826, 2003年10月10日
The Society of Instrument and Control Engineers, 日本語

非線形系の出力レギュレーション問題 (特集 非線形性に挑む--システム制御理論の最前線)
山下 裕, 計測と制御, 42, 10, 821, 826, 2003年10月
計測自動制御学会, 日本語

遠隔制御のおける伝送遅延・情報欠落の補償
山下 裕, 計測と制御 = Journal of the Society of Instrument and Control Engineers, 41, 7, 513, 518, 2002年07月10日
計測自動制御学会, 日本語

脳波を用いた論理的思考状態の推定
山川 匡史, 黒岡 武俊, 山下 裕, 西谷 紘一, ヒューマンインタフェース学会研究報告集 : human interface, 2, 3, 7, 12, 2000年06月16日
ヒュ-マンインタフェ-ス学会, 日本語

非線形制御--日本学術振興会143委員会WS19報告 (特集 新時代を担う計装・情報化テクノロジー --その可能性を探る--計装・情報化テクノロジーの活用視点と役割)
山下 裕, 計装, 43, 1, 25, 29, 2000年01月
工業技術社, 日本語

遺伝的アルゴリズムの制御への応用(第2&3回複雑系札幌シンポジウム講究録,研究会報告)
島 公脩, 山下 裕, 物性研究, 66, 4, 659, 662, 1996年
物性研究刊行会, 日本語

非線形特異摂動系の出力トラッキング制御 (情報工学専攻創立20周年記念号)
山下 裕, 岸 直輝, 島 公脩, 北海道大學工學部研究報告, 167, 0, 157, 167, 1994年01月
北海道大学, 日本語

General Nonlinear System の制御系設計
山下 裕, 計測と制御 = Journal of the Society of Instrument and Control Engineers, 31, 8, 859, 864, 1992年08月10日
計測自動制御学会, 日本語

ニュ-ラルネットワ-クによる学習・適応制御 (ニュ-ラルネット<特集>)
山下 裕, 島 公脩, 石動 善久, 計測と制御, 30, 4, p302, 308, 1991年04月
計測自動制御学会, 日本語

非線形制御系の設計アルゴリズムとCAD (非線形システム特集号)
石動 善久, 山下 裕, 島 公脩, システム・制御・情報, 33, 9, p445, 453, 1989年09月
システム制御情報学会, 日本語

非線形システム制御論
島 公脩, 石動 善久, 山下 裕, 渡邉 昭義, 川村 武, 横道 政裕
コロナ社, 1997年, 4339031674, 日本語

「非線形システム論」　　　　　　　　　　　　　　　
計測自動制御学会, 1993年

システム制御理論特論　　　　　　　　　　　　　　　
北海道大学
2014年04月 - 現在

メカトロニクス基礎　　　　　　　　　　　　　　　
北海道大学
2011年04月 - 現在

ディジタル制御　　　　　　　　　　　　　　　
北海道大学
2009年10月 - 現在

線形システム論　　　　　　　　　　　　　　　
北海道大学
2004年10月 - 現在

非線形システム論　　　　　　　　　　　　　　　
北海道大学
2004年10月 - 2006年03月

不連続あるいは正定でない入力コストを用いた省エネルギー制御
科学研究費助成事業
2019年04月01日 - 2022年03月31日
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, 基盤研究(B), 北海道大学, 19H02157

制御リアプノフ関数を用いた入力分配制御
科学研究費補助金(基盤研究(B))
2016年04月 - 2019年03月
山下 裕
日本学術振興会, 研究代表者, 競争的資金

トポロジーに基づく意志決定を考慮した制御理論の構築
科学研究費助成事業
2015年04月01日 - 2018年03月31日
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, 基盤研究(B), 東京理科大学, 15H04022

Radon測度上の動的システムの研究と都市構造遷移モデルへの応用
科学研究費補助金(挑戦的萌芽研究)
2014年04月 - 2017年03月
山下 裕
日本学術振興会, 研究代表者, 競争的資金

一般化半凹関数に基づく非線形制御工学の確立
科学研究費助成事業
2011年04月01日 - 2014年03月31日
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, 基盤研究(B), 東京理科大学, 23360185

位相空間上における動的システムの安定性解析
科学研究費助成事業
2011年 - 2013年
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, 若手研究(B), 東京理科大学, 23760391

状態ジャンプ系変換を用いた非線形系の制御に関する研究
科学研究費補助金(基盤研究(B))
2010年 - 2012年
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。
日本学術振興会, 基盤研究(B), 北海道大学, 研究代表者, 競争的資金, 22360167

多様体の大域的構造を考慮した非線形制御理論の構築
科学研究費補助金(基盤研究(C))
2007年 - 2009年
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, 基盤研究(C), 北海道大学, 研究代表者, 競争的資金, 19560435

心身状態と認知情報処理を融合させたプラントオペレータモデルの開発と応用
科学研究費補助金(基盤研究(B))
2002年 - 2005年
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, 基盤研究(B), 奈良先端科学技術大学院大学, 連携研究者, 競争的資金, 14380179

微分不可能コントローラを用いた制御系設計
科学研究費補助金(基盤研究(C))
2003年 - 2004年
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, 基盤研究(C), 奈良先端科学技術大学院大学->北海道大学, 研究代表者, 競争的資金, 15560378

不変性の概念による制御理論の構成と入門教程の開発に関する研究
科学研究費補助金(基盤研究(C))
2001年 - 2003年
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, 基盤研究(C), 北海道大学, 連携研究者, 競争的資金, 13650479

微分・代数方程式で表された非線形システムの制御
科学研究費補助金(基盤研究(C))
2000年 - 2002年
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, 基盤研究(C), 奈良先端科学技術大学院大学, 研究代表者, 競争的資金, 12650446

プラントオペレータの異常対応時における心理状態の測定と支援システムへの応用
科学研究費補助金(基盤研究(B))
2000年 - 2001年
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, 基盤研究(B), 奈良先端科学技術大学院大学, 連携研究者, 競争的資金, 12480098

プラントワイド制御システムのモデリングとシミュレーション
科学研究費補助金(基盤研究(C))
1997年 - 1998年
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, 基盤研究(C), 奈良先端科学技術大学院大学, 連携研究者, 競争的資金, 09650830

非線形制御系のロバスト設計
科学研究費補助金(一般研究(B))
1994年 - 1995年
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, 一般研究(B), 北海道大学, 連携研究者, 競争的資金, 06452248

ハミルトン・ヤコビ偏微分方程式の数値解法
科学研究費補助金(奨励研究(A))
1994年 - 1994年
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, 奨励研究(A), 北海道大学, 研究代表者, 競争的資金, 06750426

遺伝的アルゴリズムによる制御
科学研究費補助金(奨励研究(A))
1993年 - 1993年
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, 奨励研究(A), 北海道大学, 研究代表者, 競争的資金, 05855056

制御経路積分によるシステム理論の研究
科学研究費補助金(一般研究(C))
1991年 - 1992年
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...
文部科学省, 一般研究(C), 北海道大学, 連携研究者, 競争的資金, 03805020

非線形制御理論　　　　　　　　　　　　　　　
競争的資金

Nonlinear control theory　　　　　　　　　　　　　　　
競争的資金