• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 A
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• pp.135-138
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• 2003

In this paper, we provide a reliable few controller design method for descriptor systems satisfying asymptotic stability with $H_\infty$ norm bound and all actuator failures occurred within the pre-specified subset. The proper condition for the existence of a reliable $H_\infty$ controller and the controller design method are proposed by linear matrix inequality(LMI), Schur complements, and singular value decomposition. All solutions can be obtained simultaneously because the presented sufficient condition can be expressed as an LMI form.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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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.

• International Journal of Control, Automation, and Systems
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• 제6권6호
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• pp.954-959
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• 2008

This paper is concerned with the reliable $H_{\infty}$ controller design problem for uncertain linear systems against actuator failures. In the design, the $H_{\infty}$ performance of the closed-loop system is optimized during normal operation(without failures) while the system satisfies a prescribed $H_{\infty}$ performance level in the case of actuator failures. Single and parameter-dependent Lyapunov function approaches are applied in designing suboptimal reliable $H_{\infty}$ controllers. Simulation studies are presented to demonstrate the effectiveness of the proposed design procedures.

• Transactions on Control, Automation and Systems Engineering
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• 제1권2호
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• pp.121-127
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• 1999

In this paper, we present robust reliable H$\infty$ controller design methods of continuous and discrete uncertain time delay systems using LMI (linear matrix inequality) technique, respectively. Also the existence conditions of state feedback control are proposed . Using some changes of variables and Schur complements, the obtained sufficient conditions are transformed into an LMI form. The closed loop system by the obtained controller is quadratically stable with H$\infty$ norm bound for all admissible uncertainties, time delay, and all actuator failures occurred within the prespecified set. We show the validity of the proposed method through numerical example.

• Transactions on Control, Automation and Systems Engineering
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• 제2권1호
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• pp.31-39
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• 2000

We present a robust and reliable H$\infty$ state-feedback controller design for linear uncertain systems, which have norm-bounded time-varying uncertainty in the state matrix, and their prespecified sets of actuators are susceptible to failure. These controllers should guarantee robust stability of the systems and H$\infty$ norm bound against parameter uncertainty and/or actuator failures. Based on the linear matrix inequality (LMI) approach, two state-feedback controller design methods are constructed by formulating to a set of LMIs corresponding to all failure cases or a single LMI that covers all failure cases, with an additional costraint. Effectiveness and geometrical property of these controllers are validated via several numerical examples. Furthermore, the proposed LMI frameworks can be applied to multiobjective problems with additional constraints.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.401-404
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• 1998

In this paper, we present robust reliable $H\infty$ controller design methods of continuous and discrete uncertain time delay systems through LMI(linear matrix inequality) approach, respectively. Also the existence conditions of state feedback control are proposed. Using some changes of varables and Schur complements, the obtained sufficient conditions are transformed into LMI form. We show the validity of the proposed method through numerical examples.

• 전자공학회논문지SC
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• 제41권4호
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• pp.29-37
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• 2004

본 논문에서는 구동기 고장을 가지는 시간지연 특이시스템의 신뢰 H/sub ∞/ 상태궤환 제어기 설계방법을 제안한다. 미리 설정한 영역내에서의 구동기 고장이 발생함에도 불구하고 특이시스템의 점근적 안정성(asymptotic stability)과 H/sub ∞/ 성능지수를 만족하는 신뢰 H/sub ∞/ 제어기가 존재할 조건과 제어기 설계 기법을 선형행렬부등식, 특이값 분해(singular value decomposition), 슈어 여수정리(Schur complements), 변수 치환 등에 의하여 제시한다. 제안한 충분조건은 구하려는 모든 변수의 견지에서 하나의 선형행렬부등식으로 표현되기 때문에 모든 해를 동시에 구할 수 있다는 장점이 있다. 또한, 제안한 알고리듬을 이용하면 변수불확실성과 시간지연을 가지는 특이시스템에 대한 강인 신뢰(robust reliable) H/sub ∞/ 제어기 설계문제에도 쉽게 확장됨을 보인다. 마지막으로, 제안한 알고리듬의 타당성을 수치예제를 통하여 확인한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.34.5-34
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• 2001

This paper presents a reliable H$\infty$ controller design for singularly perturbed systems by the delta operator approach that guarantees stability with a known H$\infty$ norm bound in case of failures in some control channels. Prespecified are the control channels that may experience failures. Sensor outage is covered in this paper It is shown that the delta systems have improved finite wort length characteristics in the example.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 A
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• pp.111-114
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• 2003

In this paper, we consider the stabilization and $H_\infty$ control of linear systems with static output feedback control. The static output feedback control represents the simplest closed-loop control that can be realized in practice, and, moreover, it is less expensive to be implemented and is more reliable. In spite of its advantages, it is one of the open problems which is not sloved analytically or numerically yet. After decompose the closed-loop system into feedback form, by adopting the small gain theorem, we obtain a sufficient condition for stabilization and a sufficient condition for It control expressed as linear matrix inequalites. Finally, we show the usefulness of our results by a numerical example.

• 한국항공우주학회지
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• 제44권1호
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• pp.57-69
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• 2016

폐루프 기준으로 $H_{\infty}$ 제어기를 설계하는 알고리즘에는 3가지(2-ARE, mu-synthesis, LMI) 방법이 있다. 본 논문에서 3가지 $H_{\infty}$ 제어기 설계 알고리즘에 대한 기초 이론을 종합하고, Matlab$^{TM}$에 구현된 함수가 사용될 경우, 실무입장에서 가장 적절하다고 판단되는 $H_{\infty}$ 제어기 설계 알고리즘 제시를 위해 인공위성 자세 제어기 설계 후 결과를 비교 분석하였다: 2-ARE 방법과 LMI 방법은 robust stability, robust performance 및 control authority 측면에서 거의 유사하였으나, LMI 방법에 비해 2-ARE 방법이 weighting 함수설계에 더 민감하였고, mu-synthesis 방법은 다른 2가지 설계 방법에 비해 성능면에서 다소 떨어지고, control authority가 크게 나타났다. 따라서 인공위성 자세제어 설계를 위해 실무 관점에서 LMI 방법이 더 편리한 설계 알고리즘이라는 결론을 얻었다.