Papers by Tadashi Ishihara
Iterative learning control using information database
Proceedings of the 37th SICE Annual Conference. International Session Papers
In this paper, the problem of convergence rate in the initial iterations for iterative learning c... more In this paper, the problem of convergence rate in the initial iterations for iterative learning control schemes is addressed. Iterative learning control using information database (ILCID) is proposed for improving the convergence rate in the initial iterations. It is assumed that proper and efficient selection of initial control input can improve the convergence rate in the initial iterations. The initial control input for a new desired trajectory is constructed by using the information database based on a similarity index defined in this paper. This method is very general and can be applicable to all iterative learning algorithms
LQG/LTR procedure using reduced-order Kalman filters
International Journal of Control
ABSTRACT This paper discusses a linear-quadratic-Gaussian/loop transfer recovery (LQG/LTR) proced... more ABSTRACT This paper discusses a linear-quadratic-Gaussian/loop transfer recovery (LQG/LTR) procedure using reduced-order Kalman filters by extending known exact-recovery result. The state-space realisation commonly used for reduced-order observer design is employed. The zero structure intrinsic to the realisation is revealed. Asymptotic recovery is achieved using a non-singular reduced-order Kalman filter with a parameterised set of covariance matrices. The proposed procedure provides a systematic method for directly designing reduced-order LQG controllers without additional coordinate transformations. A numerical design example for a simple multivariable plant is presented to compare the proposed design with the standard LQG/LTR design using a full-order Kalman filter.
Transactions of the Society of Instrument and Control Engineers, 1993
Stability analysis of an optimal linear system with white coefficients: the influence of an incorrect covariance of the coefficients
International Journal of Control, 1985
Consider the quadratic optimal control problems for scalar linear stochastic systems with two whi... more Consider the quadratic optimal control problems for scalar linear stochastic systems with two white coefficients. The influence of an incorrect covariance of the coefficients on the stability of the closed-loop systems is analysed by elementary methods. The set of the true covariance of the coefficients in the systems stabilized by the optimal control designed on a nominal covariance is obtained. It is shown that this set is classified into several patterns according to the parameters of the systems and the weighting coefficient in the performance index and that the particular control gains stabilize the systems with large uncertainty.
A Design Method of High Order Repetitive Controllers
IFAC-PapersOnLine
IEEE Transactions on Systems, Man, and Cybernetics
The authors propose a simple discrete-time design of robust iterative learning controllers taking... more The authors propose a simple discrete-time design of robust iterative learning controllers taking account of the transient behavior as well as the uncertainty of a plant. Using the impulse response sequence of a plant, we give a simple finite dimensional formulation of the problem. Assuming that a nominal impulse response sequence is given, it is proposed that a design based on the minimization of a quadratic performance index that can be regarded as a measure for the transient performance. Then the effect of the error in the impulse response data is analyzed. It is shown that an excessively high order controller is not robust in the sense that the error severely deteriorates the transient Performance. To obtain a robust controller with a reasonable order, we proposed a design based on a probabilistic modeling of the error in the impulse response data. The controller is obtained by minimizing an averaged quadratic performance index. Simulation examples are presented to illustrate the effectiveness of the proposed methods. 0018-9472/92$03.00 0 1992 IEEE S. Kodama and N. Suda, "Matrix theory for systems and control," Soc. Instrum. Contr. Eng., 1978 (in Japanese). M. Brady et al., Robot Motion: Planning and Control.
SICE '95. Proceedings of the 34th SICE Annual Conference. International Session Papers, 2000
For Multiobjective Control Systems Design, we use Genetic Algorithms to find the Pareto Optimal s... more For Multiobjective Control Systems Design, we use Genetic Algorithms to find the Pareto Optimal set of various control system performance indices. We also propose a modified multiobjective selection scheme and the use of the improved rank-based fiitness assignment. By combining multiobjective genetic algorithm (MGA) with the pole-zero placement algorithm wihich can avoid specified pole-zero cancellations, we construct a MATLAB based software package for the computer-aided control system design (CACSD) system for two degree-of-freedom discrete-time control systems. This CACSD system provides a large freedom in the choice of controller structure and in the design specifications. Effectiveness of the proposed CACSD system is illustrated by a design example whcre the multiobjective optimization by GA is compared with a goal attainment method in MATLAB OPTIMIZATION TOOLBOX.
Transactions of the Society of Instrument and Control Engineers, 1997
For discrete-time plants with direct feedthrough terms, we consider a loop transfer recovery (LTR... more For discrete-time plants with direct feedthrough terms, we consider a loop transfer recovery (LTR) technique based on the Riccati equation formalism. We find that the recovery procedure at the plant input side should utilize the correlation between a disturbance and an observation noise. The variance of the observation noise component independent of the disturbance is taken as a parameter for the recovery. It should be noted that most discrete-time models of practical interest are non-minimum phase.
Estimation of Solid Friction in Mechanical Systems
대한전자공학회 92 한국 자동제어학술회의 논문집 국제학술편, Oct 1, 1992
適応カルマンフィルタによる速度推定法
Journal of the Visualization Society of Japan, 1992
Discrete-time LTR design of optimal output disturbance cancellation controllers using filtering-type Kalman filters
2015 10th Asian Control Conference (ASCC), 2015
カルマンフィルタを用いて摩擦を補償するサーボ系の構成
Transactions of the Japan Society of Mechanical Engineers Series C, 1990
不等式制約法による直結フィードバック制御系の設計
Transactions of the Japan Society of Mechanical Engineers Series C, 1993
Multi-objective Genetic Algorithms for the Method of Inequalities
Control Systems Design, 2005
ABSTRACT Global search capability of genetic algorithms (GAs) provides an attractive method for s... more ABSTRACT Global search capability of genetic algorithms (GAs) provides an attractive method for solving inequalities. For multi-objective optimisation, various multi-objective genetic algorithms (MGAs) have been proposed. However, due to the fundamental difference between the method of inequalities and conventional multi-objective optimisation, it is not immediately apparent how MGAs should be used for solving inequalities. In this chapter, the use of MGAs in the method of inequalities is discussed. For the effective use of MGAs, an auxiliary vector performance index, related to the set of inequalities, is introduced. A simple MGA with Pareto ranking is proposed in conjunction with the auxiliary vector index. The performance of the proposed MGA is tested on a special set of test problems and control design benchmark problems.
The partial loop transfer recovery for servosystems
Proceedings of the IEEE Internatinal Symposium on Intelligent Control, 2002
不等式制約法によるロバストサーボ系の設計
Transactions of the Society of Instrument and Control Engineers, 1991
Model-Based Velocity Estimation Using the Kalman Filter
Flow Visualization VI, 1992
Uploads
Papers by Tadashi Ishihara