• 전기학회논문지
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• 제56권9호
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• pp.1648-1654
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• 2007

In this paper, we consider the design of $H_\infty$ high-gain state feedback control for time-delayed linear systems with limited actuator capacities. The high-gain control means that the control permits the predetermined degree of saturation. Based on new Lyapunov-Krasovskii functional, we derive a result in the form of matrix inequalities. The matrix inequalities are consisted of LMIs those confirm the positive definiteness of Lyapunov- Krasovskii functional, satisfaction of predetermined degree of saturation, reachable set and $L_2$ gain constraint. The result is dependent on the bound of time-delay and its rate, predetermined degree of saturation, actuator capacity, and the allowed size of disturbances. Finally, we give a numerical example to show the effectiveness and usefulness of our result.

• 전기전자학회논문지
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• 제17권1호
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• pp.83-88
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• 2013

본 논문에서는 입력과 출력에 동시에 시간 지연이 존재하는 피드포워드 비선형시스템에 대한 출력 피드백 제어 방법을 제안한다. 제안한 출력 피드백 제어기는 선형관측기와 선형제어기로 구성된다. Lyapunov-Krasovskii 정리를 이용하여 임의의 크기를 갖는 시간지연에 대하여 전역적 점근 안정도를 보장함을 증명한다. 마지막으로 제안한 결과의 유효성을 증명하기 위하여 모의실험 예제를 제공한다.

• Journal of Electrical Engineering and Technology
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• 제13권6호
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• pp.2521-2529
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• 2018

This paper deals with a sampled-data tracking control problem for the Takagi-Sugeno fuzzy system with external disturbances. We derive a stability condition guaranteeing both asymptotic stability and H-infinity tracking performance by employing a newly proposed time-dependent line-integral fuzzy Lyapunov-Krasovskii functional. A new integral inequality is also introduced, by which the proposed stability condition is formulated in terms of linear matrix inequalities. Finally, the effectiveness of the proposed method is demonstrated through a simulation example.

• 전기학회논문지
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• 제66권1호
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• pp.127-136
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• 2017

This paper investigates improved stability and stabilization criteria for sampled-data control systems. By using a suitable and newly constructed augmented Lyapunov-Krasovskii functional and some recent mathematic techniques such as auxiliary function-based integral inequalities, sufficient conditions for stability and stabilization conditions are derived within the framework of linear matrix inequalities(LMI) form. The superiority and validity of the proposed results are illustrated by three numerical examples.

• 전기학회논문지
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• 제60권3호
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• pp.620-624
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• 2011

This paper propose a new delay-dependent stability criterion of neutral time-delay systems. By employing double-integral terms in augmented states and constructing a new Lyapunov-Krasovskii's functional, a delay-dependent stability criterion is established in terms of Linear Matrix Inequality. Through numerical examples, the validity and improvement results obtained by applying the proposed stability criterion will be shown.

• 대한전기학회논문지:시스템및제어부문D
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• 제55권4호
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• pp.147-153
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• 2006

In this paper, we propose a new delay-dependent criterion on the robust stability of time-delayed linear systems having norm bounded uncertainties. Based on new form of Lyapunov-Krasovskii functional and the Newton-Leibniz formula, we drive a result in the form of LMI which guarantees the robust stability without any model transformation. The Newton-Leibniz equation was used to relate the cross terms with free matrices. Finally, we show the usefulness of our result by two numerical examples.

• 전기학회논문지
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• 제59권8호
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• pp.1464-1470
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• 2010

In this paper, we consider the $H_{\infty}$ control of time-delayed linear systems with saturating actuators. The considered time-delay is a time-varying one having bounds on magnitude and time-derivative, and the control permits the predetermined degree of saturation. Based on two modified Lyapunov-Krasovskii(L-K) functionals, we derive a $H_{\infty}$ control in the form of linear matrix inequalities(LMI) having three non-convex design parameters. The result is dependent on the characteristics of time-delay, predetermined degree of saturation level, and bound of disturbance. Finally, we give a comparative example to show the effectiveness and usefulness of our result.

• 전기학회논문지
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• 제60권9호
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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.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 D
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• pp.1751-1752
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• 2006

이 논문에서는 불확적성을 지닌 시간지연 선형시스템에 대한 새로운 안정화 조건을 유도한다. 기존의 안정화 조건보다 향상된 안정화 조건은 이전의 Lyapunov-Krasovskii 후보 함수를 보다 일반화 한 새로운 Lyapunov-Krasovskii 후보 함수와 LMI 변수들간의 관계성을 표현해주는 자유행렬 변수의 개념을 이용한 개선된 형태의 벡터-행렬 등식에 의하여 유도되어진다. 새로운 안정화 조건은 LMI 형태로 제시되었기 때문에 제시된 안정화 조건의 유용성을 쉽게 검증 가능할 뿐만 아니라 주어진 예제를 통한 기존의 결과들과의 비교를 통해 이전의 결과들보다 보다 더 큰 시간지연 값 및 불확정량에 대하여도 안정성을 보장해 줌을 확인할 수 있다.

• 전자공학회논문지
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• 제50권7호
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• pp.239-243
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• 2013

본 논문에서는 입력에 시간 지연이 존재하는 삼각구조의 비선형시스템에 대한 출력 피드백 제어방법을 제안한다. 제안한 제어기는 고이득 관측기와 선형제어기로 구성한다. Lyapunov-Krasovskii 정리를 이용하여 점근적 안정도를 보장하는 입력지연의 크기를 유도한다. 마지막으로 제안한 결과의 유효성을 증명하기 위하여 모의실험 예제를 제공한다.