• Title, Summary, Keyword: robust stability

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Delay-dependent and Parameter-dependent Robust Stability for Discrete-time Delayed Uncertain Singular Systems (이산시간 지연 불확실 특이시스템의 지연 종속 및 변수 종속 강인 안정성)

  • Kim, Jong-Hae
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.4
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    • pp.788-792
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    • 2010
  • The problem of delay-dependent and parameter-dependent robust stability condition for discrete-time uncertain singular systems with polytopic uncertainty and interval time-varying delay is considered. A new robust stability condition based on parameter-dependent Lyapunov function is derived in terms of LMI (linear matrix inequality). Moreover, the proposed robust stability condition is a general condition for both singular and non-singular systems. A numerical example is presented to demonstrate the effectiveness of the proposed method.

Design of a repetitive controller for the system with unstructured uncertainty (비구조적인 불확실성을 가지는 시스템에 대한 반복 제어기의 설계)

  • 도태용;문정호;정명진
    • 제어로봇시스템학회:학술대회논문집
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    • pp.779-782
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    • 1996
  • Repetitive control is a proposed control strategy in view of the internal model principle and achieves a high accuracy asymptotic tracking property by implementing a model that generates the periodic signals of period into the closed-loop system. Since the repetitive control system contains a periodic signal generator with positive feedback loop, which reduces the stability margin, in the overall closed-loop system, the stability of the closed-loop system should be considered as an important problem. In case that a real system has plant uncertainties which are not represented through modeling, the robust stability problem of the repetitive control system has not been considered sufficiently. In this paper, we propose the robust stability condition for the system with modeling uncertainty. The proposed robust stability condition will be obtained using the robust performance condition in the H$_{\infty}$ control. Moreover, by use of the proposed robust stability condition, we propose a procedure that designs a repetitive controller and a feedback controller simultaneously which can stabilize the overall closed-loop system robustly and which can also do the closedloop system without repetitive controller..

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Robust Optimal Bang-Bang Controller Using Lyapunov Robust Stability Condition (Lyapunov 강인 안정성 조건을 이용한 강인 최적 뱅뱅 제어기)

  • Park Young-Jin;Moon Seok-Jun;Park Youn-Sik;Lim Chae-Wook
    • Journal of Institute of Control, Robotics and Systems
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    • v.12 no.5
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    • pp.411-418
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    • 2006
  • There are mainly two types of bang-bang controllers for nominal linear time-invariant (LTI) system. Optimal bang-bang controller is designed based on optimal control theory and suboptimal bang-bang controller is obtained by using Lyapunov stability condition. In this paper, the suboptimal bang-bang control method is extended to LTI system involving both control input saturation and structured real parameter uncertainties by using Lyapunov robust stability condition. Two robust optimal bang-bang controllers are derived by minimizing the time derivative of Lyapunov function subjected to the limit of control input. The one is developed based on the classical quadratic stability(QS), and the other is developed based on the affine quadratic stability(AQS). And characteristics of the two controllers are compared. Especially, bounds of parameter uncertainties which theoretically guarantee robust stability of the two controllers are compared quantitatively for 1DOF vibrating system. Moreover, the validity of robust optimal bang-bang controller based on the AQS is shown through numerical simulations for this system.

Robust attitude control and analysis for 3-axis stabilized spacecraft using sliding mode control (슬라이딩 모드 제어를 이용한 3축 안정화 위성의 자세 제어및 강건성 해석)

  • 신동준;김진호
    • 제어로봇시스템학회:학술대회논문집
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    • pp.692-695
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    • 1997
  • Nonlinear robust attitude controller for 3-axis stabilized spacecraft is designed. Robust stability analysis for nonlinear spacecraft system with disturbance is conducted. External disturbances and parametric uncertainties decrease Spacecraft's attitude pointing accuracy. Sliding Mode Control(SMC) provides stability of system in the face of these disturbances and uncertainties. The concept of quadratic boundedness and quadratic stability are applied to the robust analysis for the nonlinear spacecraft system subject to bounded disturbance torques. Numerical simulation is conducted to compare the analysis result and actual nonlinear simulation. The simulation show that analysis result is valid.

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Robust Stability Analysis of Fuzzy Feedback Linearization Control Systems

  • Park, Chang-Woo;Lee, Chang-Hoon;Park, Mignon
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.2 no.1
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    • pp.78-82
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    • 2002
  • In this paper, we have studied a numerical stability analysis method for the robust fuzzy feedback linearization regulator using Takagi-Sugeno fuzzy model. To analyze the robust stability, we assume that uncertainty is included in the model structure with known bounds. For these structured uncertainty, the robust stability of the closed system is analyzed by applying Linear Matrix Inequalities theory following a transformation of the closed loop systems into Lur'e systems.

Experimental Study on Stability of Robust Saturation Controller (강인 포화 제어기의 안정성에 관한 실험적 연구)

  • Lim, Chae-Wook;Moon, Seok-Jun;Park, Youngjin;Park, Yun-Sik
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.16 no.2
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    • pp.207-213
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    • 2006
  • In our previous research, we proposed a robust saturation controller which involves both control input saturation and structured real parameter uncertainties. This controller can analytically prescribed the upper and lower bounds of parameter uncertainties, and guarantee the closed-loop robust stability of the system in the presence of actuator's saturation. And the availability and the effectiveness of the proposed robust saturation controller were verified through numerical simulations. In this paper, we verify the robust stability of this controller through experimental tests. Expecially, we show unstable cases of other controllers in comparison with this controller. Experimental tests are carried out in the laboratory using a two-story test structure with a hydraulic-type active mass damper.

A Study on Power System Stability Enhancement by Robust Control of SPFC and Generators

  • Lee, Byung-Ha
    • KIEE International Transactions on Power Engineering
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    • v.4A no.3
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    • pp.109-114
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    • 2004
  • In this paper, the H$\infty$ control method is applied in the control of SPFC and generators in order to obtain the robust stability performance of the power system. Moreover, a SPFC H$\infty$ controller based on loop shaping is designed to achieve first-rate tracking properties in addition to the robust stability. This robust control method is applied to a Ward and Hale 6-bus power system and the effects are analyzed. The MATLAB program is used for simulation of the robust controller.

Robust Control via Peak Control of Sensitivity Function (민감도 함수의 최대치 제어를 통한 강인제어)

  • Suh, Sang-Min
    • Journal of Institute of Control, Robotics and Systems
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    • v.15 no.11
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    • pp.1071-1075
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    • 2009
  • This article describes a robust control method by using peak control of a sensitivity function in the state-feedback control systems. This method apparently reduces the peak, and as a result makes closed loop systems more stable. The designed closed loop systems also make the response to an external step disturbance more fast with a lower undershoot. At the conclusion, it is verified that the proposed method enhances robust stability and robust performance to parametric uncertainties through $\mu$-plot.

Research on Robust Stability Analysis and Worst Case Identification Methods for Parameters Uncertain Missiles

  • Hou, Zhenqian;Liang, Xiaogeng;Wang, Wenzheng
    • International Journal of Aeronautical and Space Sciences
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    • v.15 no.1
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    • pp.63-73
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    • 2014
  • For robust stability analysis of parameters uncertainty missiles, the traditional frequency domain method can only analyze each respective channel at several interval points within uncertain parameter space. Discontinuous calculation and couplings between channels will lead to inaccurate analysis results. A method based on the ${\nu}$-gap metric is proposed, which is able to comprehensively evaluate the robust stability of missiles with uncertain parameters; and then a genetic-simulated annealing hybrid optimization algorithm, which has global and local searching ability, is used to search for a parameters combination that leads to the worst stability within the space of uncertain parameters. Finally, the proposed method is used to analyze the robust stability of a re-entry missile with uncertain parameters; the results verify the feasibility and accuracy of the method.

Stability analysis to generally structured robust control problems

  • Cho, K.H.;Lim, J.T.
    • 제어로봇시스템학회:학술대회논문집
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    • pp.369-372
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    • 1994
  • In this paper, the robust stability of characteristic polynomials with respect to real parameter variations is investigated through a new functional approach. Specifically there is no restriction on the interrelationship between coefficients of the polynomials. This allows one to treat the robust stability problems alike without distinction as to continuous or discrete time systems. Necessary condition and sufficient condition for the robust stability are shown and some examples extracted from two-link planar manipulator are provided.

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