• Title, Summary, Keyword: sufficient uncertainty bound

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Robust and Reliable $H_\infty$ Control for Linear Systems with Parameter Uncertainty (파라메타 불확실성을 갖는 선형시스템에 대한 강한 신뢰 $H_\infty$제어)

  • 서창준;김병국
    • 제어로봇시스템학회:학술대회논문집
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    • pp.498-503
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    • 1993
  • In this paper, a robust and reliable H$_{\infty}$ control problem is considered for linear uncertain systems with time-varying norm-bounded uncertainty in the state matrix, which performs well despite of actuator outages. Using linear static state feedback and the quadratic stabilization with H$_{\infty}$-norm bound, a robust and reliable H$_{\infty}$ controller is obtained that stabilizes the plant and guarantees an H$_{\infty}$-norm bound constraint on disturbance attenuation for all admissible uncertainties and normal state as well as faulty state of actuators. It provides a sufficient condition for robust and reliable stabilization with H$_{\infty}$-norm bound. Reliability is guaranteed provided actuator outages only occur within a prespecified subset of actuators.tors.

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Stability Bound for Time-Varying Uncertainty of Positive Time-Varying Discrete Systems with Time-Varying Delay Time (시변 지연시간을 갖는 양의 시변 이산시스템의 시변 불확실성의 안정범위)

  • Han, Hyung-Seok
    • Journal of Institute of Control, Robotics and Systems
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    • v.22 no.6
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    • pp.424-428
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    • 2016
  • A simple new sufficient condition for asymptotic stability of the positive linear time-varying discrete-time systems, with unstructured time-varying uncertainty in delayed states, is established in this paper Compared with previous results that cannot be applied to time-varying systems; the time-varying system and delay time are considered simultaneously in this paper. The proposed conditions are compared with suitable conditions for the typical discrete-time systems. The considerations are illustrated by numerical examples of previous work.

Stability Bound for Time-Varying Uncertainty of Time-varying Discrete Interval System with Time-varying Delay Time (시변 지연시간을 갖는 이산 구간 시변 시스템의 시변 불확실성의 안정범위)

  • Han, Hyung-seok
    • The Journal of Advanced Navigation Technology
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    • v.21 no.6
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    • pp.608-613
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    • 2017
  • In this paper, we consider the stability bound for uncertainty of delayed state variables in the linear discrete interval time-varying systems with time-varying delay time. The considered system has an interval time-varying system matrix for non-delayed states and is perturbed by the unstructured time-varying uncertainty in delayed states with time-varying delay time within fixed interval. Compared to the previous results which are derived for time-invariant cases and can not be extended to time-varying cases, the new stability bound in this paper is applicable to time-varying systems in which every factors are considered as time-varying variables. The proposed result has no limitation in applicable systems and is very powerful in the aspects of feasibility compared to the previous. Furthermore. the new bound needs no complex numerical algorithms such as LMI(Linear Matrix Inequality) equation or upper solution bound of Lyapunov equation. By numerical examples, it is shown that the proposed bound is able to include the many existing results in the previous literatures and has better performances in the aspects of expandability and effectiveness.

Discrete-Time Robust Guaranteed Cost Filtering for Convex Bounded Uncertain Systems With Time Delay

  • Kim, Jong-Hae
    • Transactions on Control, Automation and Systems Engineering
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    • v.4 no.4
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    • pp.324-329
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    • 2002
  • In this paper, the guaranteed cost filtering design method for linear time delay systems with convex bounded uncertainties in discrete-time case is presented. The uncertain parameters are assumed to be unknown but belonging to known convex compact set of polytotype less conservative than norm bounded parameter uncertainty. The main purpose is to design a stable filter which minimizes the guaranteed cost. The sufficient condition for the existence of filter, the guaranteed cost filter design method, and the upper bound of the guaranteed cost are proposed. Since the proposed sufficient conditions are LMI(linear matrix inequality) forms in terms of all finding variables, all solutions can be obtained simultaneously by means of powerful convex programming tools with global convergence assured. Finally, a numerical example is given to check the validity of the proposed method.

Robust Guaranteed Cost Filtering for Uncertain Systems with Time-Varying Delay Via LMI Approach

  • Kim, Jong-Hae
    • Transactions on Control, Automation and Systems Engineering
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    • v.3 no.1
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    • pp.27-31
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    • 2001
  • In this paper, we consider the guaranteed cost filtering design method for time-varying delay system with parameter uncertainties by LMI(Linear Matrix Inequality) approach. The objective is to design a stable guaranteed cost filter which minimizes the guaranteed cost fo the closed loop systems in filtering error dynamics. The sufficient conditions for the existence of filter, the guaranteed cost filter design method, and th guaranteed cost upper bound are proposed by LMI technique in terms of all finding variables. Finally, we give an example to check the validity of the proposed method.

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Delay-dependent Guaranteed Cost Control for Uncertain Time Delay System

  • Lee, In-Beum;Choi, Jin-Young
    • 제어로봇시스템학회:학술대회논문집
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    • pp.62.4-62
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    • 2001
  • In this paper, we propose a delay-dependent guaranteed cost controller design method for uncertain linear systems with time delay. The uncertainty is norm bounded and time-varying. A quadratic cost function is considered as the performance measure for the given system. Based on the Lyapunov method, sufficient condition, which guarantees that the closed-loop system is asymptotically stable and the upper bound value of the closed-loop cost function is not more than a specied one, is derived in terms of Linear Matrix Inequalities(LMIs) that can be solved sufficiently. A convex optimization problem can be formulated to design a guaranteed cost controller, which minimizes the upper bound value of the cost function. Numerical examples show the activeness of the proposed method.

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Design of Robust Guaranteed Cost State Feedback Controller for Uncertain Discrete-time Singular Systems using LMI (선형행렬부등식을 이용한 불확실성 이산시간 특이시스템의 강인 보장비용 상태궤환 제어기 설계)

  • Kim, Jong-Hae
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.57 no.8
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    • pp.1429-1433
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    • 2008
  • In this paper, we consider the design method of robust guaranteed cost controller for discrete-time singular systems with norm-bounded time-varying parameter uncertainty. In order to get the optimum(minimum) value of guaranteed cost, an optimization problem is given by linear matrix inequality (LMI) approach. The sufficient condition for the existence of controller and the upper bound of guaranteed cost function are proposed in terms of strict LMIs without decompositions of system matrices. Numerical examples are provided to show the validity of the presented method.

Guaranteed Cost Controller Design Method for Singular Systems with Time Delays using LMI (선형행렬부등식을 이용한 시간지연 특이시스템의 보장비용 제어기 설계방법)

  • 김종해
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.40 no.3
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    • pp.99-108
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    • 2003
  • This paper is concerned with the problem of designing a guaranteed cost state feedback controller for singular systems with time-varying delays. The sufficient condition for the existence of guaranteed cost controller, the controller design method, and the optimization problem to get the upper bound of guaranteed cost function are proposed by LMI(linear matrix inequality), singular value decomposition, Schur complements, and change of variables. Since the obtained sufficient conditions can be changed to LMI form, all solutions including controller gain and the upper bound of guaranteed cost function can be obtained simultaneously. Moreover, the proposed controller design method can be extended to the problem of robust guaranteed cost controller design method for singular systems with parameter uncertainties and time-varying delays. The validity of the proposed design algorithm is investigated through a numerical example.

Non-fragile robust guaranteed cost control for descriptor systems with parameter uncertainties (변수 불확실성 특이시스템의 비약성 강인 보장비용 제어)

  • Kim, Jong-Hae
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.44 no.1
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    • pp.59-66
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    • 2007
  • In this paper, we consider the non-fragile robust guaranteed cost state feedback controllers design method for descriptor systems with parameter uncertainties and static state feedback controller with multiplicative uncertainty. The sufficient condition of controller existence, the design method of non-fragile robust guaranteed cost controller, the measure of non-fragility in controller, the upper bound of guaranteed cost performance measure to minimize the guaranteed cost are presented via LMI(linear matrix inequality) technique. Also, the sufficient condition can be rewritten as LMI form in terms of transformed variables through singular value decomposition, some changes of variables, and Schur complements. Therefore, the obtained non-fragile robust guaranteed cost controller satisfies the asymptotic stability and minimizes the guaranteed cost for the closed loop descriptor systems with parameter uncertainties and controller fragility. Finally, a numerical example is given to illustrate the design method.

A New Gain Scheduled QFT Method Based on Neural Networks for Linear Time-Varying System (선형 시변시스템을 위한 신경망 기반의 새로운 이득계획 QFT 기법)

  • Park, Jae-Seon;Im, Ki-Hong
    • Journal of Institute of Control, Robotics and Systems
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    • v.6 no.9
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    • pp.758-767
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    • 2000
  • The properties of linear time-varying(LTV) systems vary because of the time-varying property of plant parameters. The generalized controller design method for linear time-varying systems does not exit because the analytic soultion of dynamic equation has not been found yet. Hence, to design a controller for LTV systems, the robust control methods for uncertain LTI systems which are the approximation of LTV systems have been generally ised omstead. However, these methods are not sufficient to reflect the fast dynamics of the original time-varying systems such as missiles and supersonic aircraft. In general, both the performance and the robustness of the control system which is designed with these are not satisfactory. In addition, since a better model will give the more robustness to the controlled system, a gain scheduling technique based on LTI controller design methods has been uesd to solve time problem. Therefore, we propose a new gain scheduled QFT method for LTV systems based on neural networks in this paper. The gain scheduled QFT involves gain dcheduling procedured which are the first trial for QFT and are well suited consideration of the properties of the existing QFT method. The proposed method is illustrated by a numerical example.

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