Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.5687/iscie.30.411

CiNii Books

Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.5687/iscie.30.27

CiNii Books

Publishing type：Research paper (scientific journal)  

DOI： 10.5687/iscie.28.41

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

Social communication created on the Internet has realized a communication form mankind never experienced in which thousands or millions of people share each other images and sounds. In this report, we present the results of virtual tug-of-war experiments using multilateral telecontrol in which clients in eight sites throughout Japan share the force sense.

DOI： 10.1109/NetGames.2014.7008966

Web of Science

Language：English   Publishing type：Research paper (international conference proceedings)  

The dynamics of the arm-driven inverted pendulum (ADIP) has strong nonlinearity that depends on the arm angle, so that the performance of control laws from a linearized model is limited around an equilibrium point. In this paper, a multi-objective gain scheduling (GS) control is considered for a large reference angle of the arm. The design conditions are reduced to polynomially parameter-dependent linear matrix inequalities that can be solved by the sum of squares technique. The validity of the GS control is shown through some nonlinear simulations and experiments, in which performance comparisons are discussed with a linear quadratic control as well as a method of state-dependent Riccati equality (SDRE). Copyright © 2011 IFAC.

DOI： 10.3182/20110828-6-IT-1002.00885

Scopus

Language：English   Publishing type：Research paper (international conference proceedings)  

This paper presents an educational research project based on a collaboration between the National Colleges of Technology (NCT) and the Toyohashi University of Technology (TUT) in Japan. First, we constructed a telecontrol system that can work on the Internet for teleoperation experiments. To transmit realistic-looking environmental information, we implemented a 3D scenography system. Here we describe our experimental apparatuses and the control experiments performed as educational experiences for NCT students. In addition, to enhance the effectiveness of the educational experience and improve the proposed telecontrol system, we designed a questionnaire for operators to fill out after they finished the experiments. In this paper, we discuss the contents of the proposed educational system and the improvement of learning motivation that we believe could result from this project. © 2011 IFAC.

DOI： 10.3182/20110828-6-IT-1002.02759

Scopus

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

The acrobot is a two-link underactuated system and its dynamics has strong nonlinearity that gives rise to difficulty of controller design. Gain scheduling (GS) control is an alternative method for stabilizing such system in a wide range of operation with desired performance specifications. In this paper, problems of GS controller design for the attitude control of the acrobot are reduced to solving polynomially parameter-dependent linear matrix inequalities (PDLMIs). The polynomially PDLMIs are relaxed by matrix sum of squares (SOS) polynomials to find feasible solutions. Several reduction techniques for the GS controller design of the acrobot are developed to decrease the amount of computation for solving the SOS problems while direct formulations are too cost to solve. For two attitude modes of the acrobot, the effectiveness of GS control is shown by experiments as well as simulations.

Web of Science

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Society of Instrument and Control Engineers  

The dynamics of acrobots, two-link underactuated system, have strong nonlinearity, so that gain scheduling (GS) control is suitable for stabilizing the system in a wide range of operation. In this paper, GS controller design problems for the attitude control are reduced to solving polynomially parameter-dependent linear matrix inequalities (PDLMIs). The polynomially PDLMIs are relaxed by matrix sum of squares (SOS) polynomials to find feasible solutions. Several reduction techniques are adopted to reduce the amount of computation for solving the SOS problems while direct formulations are too computationally expensive to solve. For two attitude modes of the acrobot, the effectiveness of GS control is shown by experiments as well as nonlinear simulations.

DOI： 10.9746/sicetr.46.373

CiNii Books

Other Link： https://jlc.jst.go.jp/DN/JALC/00354404035?from=CiNii

Publisher：The Society of Instrument and Control Engineers  

Recently, it has been shown that the methods using PDLMI (Parameter-Dependent LMI) are effective for the robust H<SUB>∞</SUB> performance analysis of the linear polytopic-type uncertain systems. Especially, the extended LMI approaches can avoid the product of the Lyapunov matrix and the system matrix by enlarging the size of LMI, and a less conservative analysis can be achieved by using these approaches. On the other hand, the redundant descriptor approaches are known as methods of consequentially enlarging the size of LMI by expanding the rep-resentation of the system. In this paper, we derive extended LMI conditions for the robust H<SUB>∞</SUB> performance analysis from the standpoint of a redundant descriptor approach. Moreover, it is examined to decrease the number of concomitant variables of the extended LMI in order to shorten time to compute the solution.

DOI： 10.9746/ve.sicetr1965.44.147

Publisher：The Society of Instrument and Control Engineers  

In this paper, we shall provide a new redundant descriptor approach to <i>H</i>_∞ state-feedback controller synthesis based on the strategy of the recently developed dilated LMIs. It is known that both of the redundant descriptor and the dilated LMI approaches are effective for robust/gain-scheduled <i>H</i>_∞ state-feedback controller synthesis when the state-space matrices of the plant are affected by uncertain/scheduling parameters. These approaches are closely related in the sense that they enlarge the size of LMIs and employ additional matrix variables to obtain more tractable LMI conditions. However, in the existing redundant descriptor approaches, some assumptions have been imposed on the the state-space matrices of the plant to avoid difficulties arising from the fictious direct feedthrough term from the disturbance inputs to the performance outputs of the resulting descriptor form. This is in sharp contrast with the dilated LMI approaches that do not require any specific assumptions on the state space matrices. To fill the gap between these two approaches, in the present paper, we revisit the redundant descriptor approaches and provide a new way to recast the state-space representations into descriptor forms by employing yet new additional variables. By employing those new additional variables, it turns out that those LMIs resulting from the descriptor approaches coincide with the known dilated LMI conditions. The role of those additional variables can be seen clearly if we view from the standpoint of the redundant descriptor approaches.

DOI： 10.9746/sicetr1965.42.750

Publisher：The Society of Instrument and Control Engineers  

Common LMI solutions are used in most multiobjective control designs, however, common LMI solutions cause conservatism. In order to reduce this conservatism, this paper presents a new multiobjective gain scheduled control design method based on non-common LMI solutions for a descriptor form LPV system. In the proposed method, the selection of descriptor variables is devised, and the feedback gain is constant in appearance. As a result, parameter-dependent LMIs are able to be transferred to the finite number of LMIs without conservatism. The proposed design method is applied to an inverted pendulum, and its validity is shown through experiments as compared with the usual design method based on common LMI solutions.

DOI： 10.9746/sicetr1965.38.677

Language：Japanese   Publisher：The Society of Instrument and Control Engineers  

In this paper, a design method of the nonlinear <i>H</i>_∞ state feedback is proposed for a nonlinear descriptor model of an inverted pendulum system. First, the nonlinear descriptor model of a polynominal type with structural uncertainties for the inverted pendulum system introduced. The descriptor variables of this model include not only state variables but also the time derivative of state variables. Next, a state-dependent matrix inequality condition, which is can be transferred to the finite number of linear matrix inequalities, for the nonlinear robust <i>H</i>_∞ control problem and the eigenvalue location problem is given. The validity of the proposed nonlinear <i>H</i>_∞ control is shown through experiments as compared with the other nonlinear <i>H</i>_∞ control.

DOI： 10.9746/sicetr1965.36.650

CiNii Books

Other Link： https://jlc.jst.go.jp/DN/JALC/00069743702?from=CiNii

Language：Japanese   Publisher：The Society of Instrument and Control Engineers  

We have already proposed a novel numerical approach to compute the approximate solution of the Hamilton-Jacobi equation in the nonlinear <i>H</i>_∞ control problems. In this paper, our proposal is applied to an inverted pendulum, and its validity is shown through experiments as compared with the linear <i>H</i>_∞ control.

DOI： 10.9746/sicetr1965.35.294

CiNii Books

Other Link： https://jlc.jst.go.jp/DN/JALC/00059446873?from=CiNii

Language：Japanese   Publisher：THE INSTITUTE OF SYSTEMS, CONTROL AND INFORMATION ENGINEERS (ISCIE)  

In this paper, a novel numerical approach of the Hamilton-Jacobi Equation (HJE) in the nonlinear <I>H</I><SUB>∞</SUB> control problems is proposed. First of all, it is assumed that the solution of the HJE is an extended quadratic form, and a state-dependent Riccati Equation (sRE) is derived. Next, the solution of the sRE is approximated with a polynominal matrix by the least square method, and the approximated solution of the HJE is selected as the extended quadratic form approximately corresponding to this polynominal. Our proposal is applied to an inverted pendulum system, and its validity is shown through simulations as compared with the linear <I>H</I><SUB>∞</SUB> control and the nonlinear<I>H</I><SUB>∞</SUB> control based on the conventional methods.

DOI： 10.5687/iscie.11.401

CiNii Books

Other Link： https://jlc.jst.go.jp/DN/JALC/00384758092?from=CiNii

Language：Japanese   Publisher：THE INSTITUTE OF SYSTEMS, CONTROL AND INFORMATION ENGINEERS (ISCIE)  

DOI： 10.5687/iscie.11.703

CiNii Books

Other Link： https://jlc.jst.go.jp/DN/JALC/00384754759?from=CiNii

DOI： 10.1541/ieejeiss1987.116.11_1211

Language：Japanese   Publisher：THE INSTITUTE OF SYSTEMS, CONTROL AND INFORMATION ENGINEERS (ISCIE)  

An induction motor is basically a nonlinear system having three inputs three outputs and in this paper, first, we show that an induction motor can be exactly linearized and decoupled. However, there is the problem that this general exact linearization system is sensitive for parameter variation. So we cope with this problem by using information that is included in approximated linearization system around an equilibrium point. Second, we design an <I>H</I><SUP>∞</SUP> controller in consideration of parameter variations for exact linearization system. We verify the validity of our proposed design method with respect to both nonlinearity and parameter variation by simulations.

DOI： 10.5687/iscie.7.195

CiNii Books

Other Link： https://jlc.jst.go.jp/DN/JALC/00384766103?from=CiNii

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

DOI： 10.11509/isciesci.55.5_159

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

DOI： 10.11509/isciesci.55.5_165