• Title/Summary/Keyword: time-varying delay

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Robust Controller Design for Uncertain Dynamic System Using Time Delay Control and Sliding Mode Control Method (시간지연 제어와 슬라이딩모드 제어기법을 이용한 불확실한 동적 시스템의 강인 제어기 설계)

  • 박병석;이인성;윤지섭;강이석
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.225-225
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    • 2000
  • We propose the hybrid robust controller for TDC(Time Delay Control) and SMC(Sliding Mode Control) method. TDC and SMC deal with the time-varying system parameters, unknown dynamics and unexpected disturbance. This controller is applied to follow the desired reference model for the uncertain time-varying overhead crane. The control performance is evaluated through simulation. The theoretical results indicate That the proposed controller shows excellent performance to an overhead crane with the uncertain time-varying parameters and disturbance.

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Adaptive Control for Discrete Process with Time Varying Delay (시변 지연시간을 갖는 이산형 프로세스의 적응제어)

  • 김영철;김국헌;정찬수;양흥석
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.35 no.11
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    • pp.503-510
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    • 1986
  • A new algorithm based on the concept of prediction error minimization is suggested to estimate the time varying delay in discrete processes. In spite of the existence of the stochastic noise, this algorithm can estimate time varying delay accurately. Computation time of this algorithm is far less than that of the previous extended parameter methods. With the use of this algorithm, generalized minimum variance control shows good control behavior in simulations.

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Stability Condition for Discrete Interval System with Time-Varying Delay Time (시변 지연시간을 갖는 이산 구간 시스템의 안정조건)

  • Han, Hyung-seok
    • Journal of Advanced Navigation Technology
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    • v.19 no.6
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    • pp.574-580
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    • 2015
  • The stability condition of linear discrete interval systems with a time-varying delay time is considered. The considered system has interval system matrices for both non-delayed and delayed states with time-varying delay time within given interval values. The proposed condition is derived by using Lyapunov stability theory and expressed by very simple inequality. Compared to previous results, the stability issue on the interval systems is expanded to time-varying delay. Furthermore, the new condition can imply the existing results on the time-invariant case and show the relation between interval time-varying delay time and stability of the system. The proposed condition can be applied to find the stability bound of the discrete interval system. Some numerical examples are given to show the effectiveness of the new condition and comparisons with the previously reported results are also presented.

Stability Condition for Discrete Interval Time-varying System with Time-varying Delay Time (시변 지연시간을 갖는 이산 구간 시변 시스템의 안정조건)

  • Han, Hyung-seok
    • Journal of Advanced Navigation Technology
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    • v.20 no.5
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    • pp.475-481
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    • 2016
  • In this paper, the new stability condition of linear discrete interval time-varying systems with time-varying delay time is proposed. The considered system has interval time-varying system matrices for both non-delayed and delayed states with time-varying delay time within given interval values. The proposed condition is derived by using Lyapunov stability theory and expressed by very simple inequality. The restricted stability issue on the interval time-invariant system is expanded to interval time-varying system and a powerful stability condition which is more comprehensive than the previous is proposed. As a results, it is possible to avoid the introduction of complex linear matrix inequality (LMI) or upper solution bound of Lyapunov equation in the derivation of sufficient condition. Also, it is shown that the proposed result can include the many existing stability conditions in the previous literatures. A numerical example in the pe revious works is modified to more general interval system and shows the expandability and effectiveness of the new stability condition.

Delay-dependent Robust $H_{\infty}$ Control for Uncertain Discrete-time Descriptor Systems with Interval Time-varying Delays in State and Control Input (상태와 입력에 구간 시변 시간지연을 가지는 불확실 이산시간 특이시스템의 지연 종속 강인 $H_{\infty}$ 제어)

  • Kim, Jong-Hae
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.1
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    • pp.193-198
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    • 2009
  • In this paper, we consider the design problem of delay-dependent robust $H{\infty}$ controller of discrete-time descriptor systems with parameter uncertainties and interval time-varying delays in state and control input by delay-dependent LMI (linear matrix inequality) technique. A new delay-dependent bounded real lemma for discrete-time descriptor systems with time-varying delays is derived. The condition for the existence of robust $H{\infty}$ controller and the robust $H{\infty}$ state feedback control law are proposed by LMI approach. A numerical example is demonstrated to show the validity of the design method.

Stability Condition for Discrete Interval Time-Varying System with Unstructured Uncertainty and Time-Varying Delay Time (비구조화된 불확실성과 시변 지연시간을 갖는 이산 시변 구간 시스템의 안정조건)

  • Hyung-seok Han
    • Journal of Advanced Navigation Technology
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    • v.26 no.6
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    • pp.504-509
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    • 2022
  • In this paper, we deal with the stability condition of linear time-varying interval discrete systems with time-varying delays and unstructured uncertainty. For the time-varying interval discrete system which has interval matrix as its system matrices, time-varying delay time within some interval value and unstructured uncertainty which can include non-linearity and be expressed by only its magnitude, the stability condition is proposed. Compared with the previous result derived by using a upper bound solution of the Lyapunov equation, the new result is derived by the form of simple inequality based on Lyapunov stability condition and has the advantage of being more effective in checking stability. Furthermore, the proposed condition is very comprehensive, powerful and inclusive the previously published conditions of various linear discrete systems, and can be expressed by the terms of magnitudes of the time-varying delay time and uncertainty, and bounds of interval matrices. The superiority of the new condition is shown in the derivation, and the usefulness and advantage of the proposed condition are examined through numerical example.

Indirect Adaptive Pole Assignment PID Controllers for Unknown Systems with time varying delay (시변 지연시간을 가지는 미지의 시스템에 대한 간접 극배치 적응 PID 제어기)

  • Nam, Hyun-Do;Ahn, Dong-Jun
    • Proceedings of the KIEE Conference
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    • 1988.07a
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    • pp.913-916
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    • 1988
  • Indirect adaptive pole assignment PID controllers for unknown systems with time varying delay, is proposed. Unknown system parameters are estimated by recursive least square method, and time varying delay is estimated using indirect predictors. Since the order of parameter vectors didn't increase, the computational burden is not largely increased in spite of using indirect adaptive control method with time varying delay estimation. Computer simulation is performed to illustrate the efficiency of the proposed method.

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Novel Results for Global Exponential Stability of Uncertain Systems with Interval Time-varying Delay

  • Liu, Yajuan;Lee, Sang-Moon;Kwon, Oh-Min;Park, Ju H.
    • Journal of Electrical Engineering and Technology
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    • v.8 no.6
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    • pp.1542-1550
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    • 2013
  • This paper presents new results on delay-dependent global exponential stability for uncertain linear systems with interval time-varying delay. Based on Lyapunov-Krasovskii functional approach, some novel delay-dependent stability criteria are derived in terms of linear matrix inequalities (LMIs) involving the minimum and maximum delay bounds. By using delay-partitioning method and the lower bound lemma, less conservative results are obtained with fewer decision variables than the existing ones. Numerical examples are given to illustrate the usefulness and effectiveness of the proposed method.

Bilateral Control with Time Domain Passivity Approach under Time-varying Communication Delay: Resetting Scheme (시간영역 수동성 기법을 이용하여 시변 시간지연 하에서 안정성을 보장하는 양방향 원격제어기: 리셋 방법)

  • Ryu, Jee-Hwan
    • Journal of Institute of Control, Robotics and Systems
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    • v.14 no.11
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    • pp.1124-1129
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    • 2008
  • Recently, two-port time-domain passivity approach was modified for time-varying communication delay. The newly proposed approach could achieve stable teleoperation even under the serious time-varying delay and packet loss communication condition. However, after some operation hour, the accumulated energy difference between the input energy from one port and the output energy at the other port caused unstable behavior until the passivity controller is activated. Resetting scheme is introduced for solving this problem, and stable bilateral teleoperation can be guaranteed without worrying about the accumulated energy difference.

Stability of Linear Systems with Interval Time-varying Delay via New Interval Decomposition (새로운 구간 분해 방법을 이용한 구간 시변지연을 갖는 선형시스템의 안정성)

  • Kim, Jin-Hoon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.9
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    • pp.1748-1753
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    • 2011
  • In this paper, we consider the stability of linear systems with an interval time-varying delay. It is known that the adoption of decomposition of delay improves the stability result. For the interval time-delay case, they applied it to the interval of time-delay and got less conservative results. Our basic idea is to apply the general decomposition to the low limit of delay as well as interval of time-delay. Based on this idea, by using the modified Lyapunov-Krasovskii functional and newly derived Lemma, we present a less conservative stability criterion expressed as in the form of linear matrix inequality(LMI). Finally, we show, by well-known two examples, that our result is less conservative than the recent results.