研究者詳細 - 瀨部　昇

論文 - 瀨部　昇

分割表示129 件中 41 - 60 件目／全件表示 >>

Characterization of the dual problem of linear matrix inequality for H-infinity output feedback control problem via facial reduction 査読有り国際誌

Waki H., Sebe N.

Mathematics of Control, Signals, and Systems 32 ( 3 ) 361 - 384 2020年07月

記述言語：英語掲載種別：研究論文（学術雑誌）

© 2020, The Author(s). This paper deals with the minimization of H∞ output feedback control. This minimization can be formulated as a linear matrix inequality (LMI) problem via a result of Iwasaki and Skelton 1994. The strict feasibility of the dual problem of such an LMI problem is a valuable property to guarantee the existence of an optimal solution of the LMI problem. If this property fails, then the LMI problem may not have any optimal solutions. Even if one can compute parameters of controllers from a computed solution of the LMI problem, then the computed H∞ norm may be very sensitive to a small change of parameters in the controller. In other words, the non-strict feasibility of the dual tells us that the considered design problem may be poorly formulated. We reveal that the strict feasibility of the dual is closely related to invariant zeros of the given generalized plant. The facial reduction is useful in analyzing the relationship. The facial reduction is an iterative algorithm to convert a non-strictly feasible problem into a strictly feasible one. We also show that facial reduction spends only one iteration for so-called regular H∞ output feedback control. In particular, we can obtain a strictly feasible problem by using null vectors associated with some invariant zeros. This reduction is more straightforward than the direct application of facial reduction.

DOI： 10.1007/s00498-020-00261-z

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85087762239&origin=inward

Initial state design for suppressing undesirable effects of controller switches 査読有り国際誌

Suyama K., Sebe N.

IFAC-PapersOnLine 53 ( 2 ) 6452 - 6458 2020年07月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Germany (online) Berlin 2020年07月11日 - 2020年07月17日

We propose a new initial state design procedure for a newly-activated controller at a controller switch. By minimizing the value of the state-dependent switching L2 gain presented in this paper, we can obtain the optimal initial state for suppressing the difference between the actuality that a controller switch occurs and the virtual situation where it does not occur.

DOI： 10.1016/j.ifacol.2020.12.1788

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85105035116&origin=inward

Learning Koopman operator under dissipativity constraints 査読有り国際誌

Hara K., Inoue M., Sebe N.

IFAC-PapersOnLine 53 ( 2 ) 1169 - 1174 2020年07月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Germany (online) Berlin 2020年07月11日 - 2020年07月17日

This paper addresses a learning problem for nonlinear dynamical systems with incorporating any specified dissipativity property. The nonlinear systems are described by the Koopman operator, which is a linear operator defined on the infinite-dimensional lifted state space. The problem of learning the Koopman operator under specified quadratic dissipativity constraints is formulated and addressed. The learning problem is in a class of the non-convex optimization problem due to nonlinear constraints and is numerically intractable. By applying the change of variable technique and the convex overbounding approximation, the problem is reduced to sequential convex optimization and is solved in a numerically efficient manner. Finally, a numerical simulation is given, where high modeling accuracy achieved by the proposed approach including the specified dissipativity is demonstrated.

DOI： 10.1016/j.ifacol.2020.12.1327

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85105111069&origin=inward

On Gain-Scheduled State-Feedback Controller Synthesis with Quadratic Stability Condition 査読有り国際誌

Ebihara Y., Sebe N., Waki H.

IEEE Control Systems Letters 4 ( 3 ) 662 - 667 2020年07月

記述言語：英語掲載種別：研究論文（学術雑誌）

© 2017 IEEE. This letter shows that, as long as continuous-time linear parameter-varying (LPV) systems are concerned, quadratic-stability-based gain-scheduled state-feedback controller synthesis offers no advantage over quadratic-stability-based fixed (parameter-independent) state-feedback controller synthesis in typical control performance specifications. We derive this counterintuitive result by properly extending the previous results on the robust versions of Finsler's lemma and the elimination lemma. We also show that this counterintuitive result is continuous-time LPV system specific, and in the discrete-time LPV system case quadratic-stability-based gain-scheduled state-feedback controller synthesis does bring improvement. These results give a proper warning about the effectiveness of the quadratic-stability-based gain-scheduled state-feedback controller synthesis.

DOI： 10.1109/LCSYS.2020.2991480

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85085477720&origin=inward

Reduction of H-infinity state feedback control problems for the MIMO servo systems 査読有り国際誌

Waki H., Sebe N.

Asian Journal of Control 22 ( 3 ) 1025 - 1037 2020年05月

記述言語：英語掲載種別：研究論文（学術雑誌）

We deal with H-infinity state feedback control problem for the multi-input-multi-output (MIMO) servo system and discuss the advantages of the facial reduction (FR) to the resulting linear matrix inequality (LMI) problems. In fact, as far as our usual setting, the dual of the LMI problem is not strictly feasible because the generalized plant has always stable invariant zeros. Thus FR is available to such LMI problems, and we can reduce and simplify the original LMI problem to a smaller-size LMI problem. As a result, we observe that the numerical performance of the SDP solvers is improved. Also, as a by-product, we obtain the best performance index of the reduced LMI problem with a closed-form expression. This helps the H-infinity performance limitation analysis. Another contribution is to reveal that the resulting LMI problem obtained from H-infinity control problem has a finite optimal value, but no optimal solutions under an additional assumption. This is also confirmed in the numerical experiment of this paper. FR also plays an essential role in this analysis.

DOI： 10.1002/asjc.1985

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85058052736&origin=inward

Fault tolerant method on position cascade control of Dc servo system 査読有り国際誌

Indriawati K., Sebe N.

Mechatronic Systems and Control 48 ( 2 ) 144 - 151 2020年04月

記述言語：英語掲載種別：研究論文（学術雑誌）

The fault of the positioning servo system due to actuator and sensor faults can endanger users and the surrounding environment; even the existing control system has a good performance to position precisely something, such as a position cascade control system. In this paper, a fault tolerant control (FTC) system has been implemented to tolerate faults automatically when the faults on actuator and sensor component of DC modular servo system have occurred. The proposed design consisted of both observers working to estimate actuator fault and later sensor fault, as well as the fault compensation mechanism that has functioned as an occurred fault corrector. The results have showed that FTC system could maintain the performance of the cascade control system of a DC modular servo system with the values of maximum overshoot, settling time, and error steady state that have been smaller than the ones without fault compensation.

DOI： 10.2316/J.2020.201-0094

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85090422845&origin=inward

半正定値計画によるH∞性能限界解析招待有り

蛯原義雄, 脇隼人, 瀬部昇

計測と制御 ( 公益社団法人計測自動制御学会 ) 59 ( 3 ) 218 - 225 2020年03月

離散時間線形時不変システム解析のための外部非負システムの構成と低次元化査読有り

蛯原義雄, 瀬部昇, 増淵泉, 脇隼人, 管野政明, 椿野大輔

システム制御情報学会論文誌 ( 一般社団法人システム制御情報学会 ) 32 ( 7 ) 284 - 293 2019年07月

記述言語：日本語掲載種別：研究論文（学術雑誌）

<p>This paper is concerned with the analysis of discrete-time LTI systems via construction of associated externally positive systems. Recently, the authors established a construction method of an externally positive system whose impulse response is given by the square of the original discrete-time LTI SISO system to be analyzed. This externally positive system allows us to characterize the <i>H</i><sub>2 </sub>norm of the original system by means of the closed-form <i>l<sub>∞</sub></i>-induced norm characterization of externally positive systems. It is nonetheless true that, for the original system of order <i>n</i>, the order of the resulting externally positive system is <i>n</i><sup>2</sup>, incurring a drastic increase in computational burden of computer-aided analysis and synthesis. With this important issue in mind, in this paper, we show that the order can be reduced down to <i>n</i>(<i>n</i>+1)<i>/</i>2 by using the elimination and duplication matrices that are intensively studied by J. R. Magnus in the 80's. In addition to the computational complexity reduction for the aforementioned <i>H</i><sub>2 </sub>analysis, we show that such construction of externally positive systems with reduced order is quite effective in semidefinite-programming-based peak value analysis of impulse responses of general LTI systems.</p>

DOI： 10.5687/iscie.32.284

その他リンク： https://ci.nii.ac.jp/naid/130007728846

Initial state design for controller switches by using state-dependent switching L2 gain 査読有り国際誌

Suyama K., Sebe N.

2019 18th European Control Conference, ECC 2019 1257 - 1262 2019年06月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Italy Naples 2019年06月25日 - 2019年06月28日

© 2019 EUCA. We propose a new method for designing the initial state of a newly-activated controller at a controller switch. By minimizing the value of a state-dependent switching L2gain through a linear matrix inequality problem, it can provide the optimal initial state for suppressing the fluctuations in transient responses after the switch.

DOI： 10.23919/ECC.2019.8796131

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85071591347&origin=inward

Minimal order observer based H-infinity controller design based on overbounding approximation method 査読有り国際誌

Kayo S., Nohmi A., Sebe N., Sato M.

2019 12th Asian Control Conference, ASCC 2019 167 - 172 2019年06月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Japan Kitakyushu 2019年06月10日 - 2019年06月12日

© 2019 JSME. In this paper, the minimal order observer based H∞ controller design is studied. The state space representation of the minimal order observer based controller is complicated and involves the product and quadratic terms of the decision variable matrices, i.e., the state feedback and observer gains. To make the design problem as a bilinear matrix inequality (BMI) problem, we represent the minimal order observer based controller by a descriptor representation, where the decision variable matrices are affinely involved. This descriptor representation enables us to design controllers by applying the overbounding approximation method for general BMI problems. The effectiveness of the proposed design procedure is demonstrated by a numerical example.

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85069940778&origin=inward

Switching L2 gain for evaluating the fluctuations in transient responses after an unpredictable system switch 査読有り国際誌

Suyama K., Sebe N.

International Journal of Control 92 ( 5 ) 1084 - 1093 2019年05月

記述言語：英語掲載種別：研究論文（学術雑誌）

© 2017, © 2017 Informa UK Limited, trading as Taylor & Francis Group. We propose a new switching L2 gain for evaluating the fluctuations in transient responses after an unpredictable switch, such as a switch caused by a failure in a control device occurring in the normal operation, between two linear time-invariant systems. We also present L2 gain conditions that enable us to compute the value of the proposed switching L2 gain. We then theoretically establish its applicability as an analysis index. Furthermore, by applying the proposed gain to switching matrix design, we show its potential applicability as a design index.

DOI： 10.1080/00207179.2017.1381884

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85031415647&origin=inward

Application of facial reduction to H-infinity state feedback control problem 査読有り国際誌

H. Waki, N. Sebe

International Journal of Control 92 ( 2 ) 303 - 316 2019年02月

記述言語：英語掲載種別：研究論文（学術雑誌）

© 2017, © 2017 Informa UK Limited, trading as Taylor & Francis Group. One often encounters numerical difficulties in solving linear matrix inequality (LMI) problems obtained from H ∞ control problems. For semidefinite programming (SDP) relaxations for combinatorial problems, it is known that when either an SDP relaxation problem or its dual is not strongly feasible, one may encounter such numerical difficulties. We discuss necessary and sufficient conditions to be not strongly feasible for an LMI problem obtained from H ∞ state feedback control problems and its dual. Moreover, we interpret the conditions in terms of control theory. In this analysis, facial reduction, which was proposed by Borwein and Wolkowicz, plays an important role. We show that the dual of the LMI problem is not strongly feasible if and only if there exist invariant zeros in the closed left-half plane in the system, and present a remedy to remove the numerical difficulty with the null vectors associated with invariant zeros in the closed left-half plane. Numerical results show that the numerical stability is improved by applying it.

DOI： 10.1080/00207179.2017.1351625

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85025143403&origin=inward

State-Dependent Switching L2 Gain for Analyzing the Fluctuations in Transient Responses after a System Switch 査読有り国際誌

Koichi Suyama, Noboru Sebe

Proceedings of 57th IEEE Conference on Decision and Control 6263 - 6268 2018年12月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

U.S.A. Miami Beach 2018年12月17日 - 2018年12月19日

© 2018 IEEE. We propose a state-dependent switching mathcal{L}-{2} gain for analyzing the fluctuations in transient response after an unpredictable switch between two linear time-invariant systems. Its value depends on the state of a pre-switch system at a switching time. Thus, it enables us to theoretically discuss the effects of the situation at a switching time on the fluctuations in transient responses after the switch. For example, its value distribution in the state space of a pre-switch system can be used for evaluating the dangerous extent of the situation at an occurrence time of a control device failure.

DOI： 10.1109/CDC.2018.8618974

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85062170815&origin=inward

Search Direction in Successive Linearization of Bilinear Matrix Inequality Problems 査読有り国際誌

Tomoki Okayama, Noboru Sebe

2018 International Conference on Information and Communication Technology Robotics, ICT-ROBOT 2018 6 pages 2018年09月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Korea Busan 2018年09月07日 - 2018年09月09日

© 2018 IEEE. This paper proposes an alternative successive linearization method which determines the search direction previously to the optimization of decision variables. The proposed method preserves the size of matrix inequality constraint to avoid the increase of the computational consumption.

DOI： 10.1109/ICT-ROBOT.2018.8549906

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85060017680&origin=inward

Sequential Convex Overbounding Approximation Method for Bilinear Matrix Inequality Problems 査読有り

Noboru Sebe

IFAC symposium on Robust Control Design 51 ( 25 ) 102 - 109 IFAC paper online 2018年09月

担当区分：責任著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Brazil Florianopolis 2018年09月03日 - 2018年09月05日

© 2018 This paper concerns with the overbounding method for solving the bilinear matrix inequality (BMI) problem. The overbounding method is essentially the same as the difference of convex optimization approach and the inner approximation method. The unified view of these methods is provided. This paper also proposes a new overbounding algorithm based on the less conservative overbounding approximation and the matrix decomposition.

DOI： 10.1016/j.ifacol.2018.11.089

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85056868873&origin=inward

State assignment method for improvement of transient response caused by controller switching 査読有り国際誌

Nakano K., Sebe N., Deguchi S., Suyama K.

IFAC Symposium on Robust Control Design 51 ( 25 ) 365 - 370 IFAC-PapersOnLine 2018年09月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Brazil Florianopolis 2018年09月03日 - 2018年09月05日

© 2018 In this paper, the suppression of undesirable transient responses caused by controller switching is considered. In some cases, we switch the feedback and the observer gains in order to improve the control performance. However, such switching causes large disturbed transient response. To suppress such undesirable transient response, we propose to assign the state of the dynamical controller. This paper shows that it can be further suppressed by attaching an observer in order to suppress the transient response caused by switching, even in the case that all the states can be measured directly. The proposed assignment rule is based on the observability gramian of the post-switching closed loop system.

DOI： 10.1016/j.ifacol.2018.11.134

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85056825826&origin=inward

Improving the Accuracy of Dynamical System Based Optical Flow Estimation by Central Difference Discretization of Time Derivative 査読有り国際誌

Yuta Akiyoshi, Noboru Sebe, Shuichi Enokida and Eitaku Nobuyama

4th International Conference on Machine Vision and Machine Learning (MVML'18) MVML107 (7 pages) 2018年08月

Control System Design for Safely Performing Preventive Maintenance 査読有り

Suyama K., Sebe N.

IEEE International Conference on Control and Automation, ICCA 1087 - 1094 2018年06月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

U.S.A. Anchorage 2018年06月12日 - 2018年06月15日

© 2018 IEEE. On the basis of fault-tolerant control theory and switching L2 gain analysis, we propose a new control system design procedure for achieving an operating state suitable for safely performing preventive maintenance of each subsystem, where the safety of the bidirectional transitions between normal operation and an operating state is guaranteed.

DOI： 10.1109/ICCA.2018.8444281

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85053153171&origin=inward

Strong feasibility of the dual problem of linear matrix inequality for H-infinity output feedback control problem 査読有り国際誌

Waki H., Sebe N.

SICE ISCS 2018 - 2018 SICE International Symposium on Control Systems 47 - 53 2018年03月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Japan Tokyo 2018年03月09日 - 2018年03月11日

© 2018 The Society of Instrument and Control Engineers - SICE. Strong feasibility (a.k.a. strict feasibility) of the dual problem of a given linear matrix inequality (LMI) is an important property to guarantee the existence of an optimal solution of the LMI problem. In particular, the LMI problem may not have any optimal solutions if the dual is not strongly feasible. This implies that the computed solutions by SDP solvers may be meaningless and useless for designing the controllers of H∞ output feedback control problems. The facial reduction is a tool to analyze and reduce such non-strongly feasible problems. We introduce the strong feasibility of the dual and facial reduction and provide the necessary and sufficient condition on the strong feasibility. Furthermore, we reveal that the condition is closely related to invariant zeros in the plant.

DOI： 10.23919/SICEISCS.2018.8330155

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85049335246&origin=inward

外部非負システムへの変換による離散時間線形時不変システムのH2解析査読有り

蛯原義雄, 瀬部昇, 増淵泉, 脇隼人, 管野政明, 椿野大輔

システム制御情報学会論文誌 ( 一般社団法人システム制御情報学会 ) 31 ( 2 ) 75 - 84 2018年02月

記述言語：日本語掲載種別：研究論文（学術雑誌）

<p>In this paper, we explore <i>H</i><sub>2 </sub>analysis techniques of general, not necessarily positive, discrete-time linear time-invariant (LTI) systems by means of positive system theory. While externally positive systems are a particular class of systems whose impulse responses take only nonnegative values, we often encounter such impulse responses even in the analysis of general LTI systems. A typical example is the computation of the <i>H</i><sub>2 </sub>norm where we focus on squared impulse responses. In view of this observation, we first clarify that we can construct an SISO externally positive system whose impulse response is given by the square of the impulse response of a given SISO LTI system. This system conversion allows us to reduce the <i>H</i><sub>2 </sub>norm computation problem of a general LTI system to the <i>l</i><i><sub>∞</sub></i>-induced norm computation problem (or <i>l</i><sub>1 </sub>problem in short) of the resulting externally positive system. It also turns out that this problem reduction enables us to derive various alternative formulas for the <i>H</i><sub>2 </sub>norm of general discrete-time LTI systems.</p>

DOI： 10.5687/iscie.31.75

その他リンク： https://ci.nii.ac.jp/naid/130006734448

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