• 제어로봇시스템학회논문지
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• 제2권1호
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• pp.1-4
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• 1996

This paper presents a state feedback $H^{\infty}$ controller design method for linear systems with delayed states and inputs. We derive a sufficient condition that the closed-loop system is asymptotically stable for all time-delays and that the $H^{\infty}$-norm of the closed-loop transfer function is less than or equal to some prescribed level $\gamma$. And we propose a sufficient condition for the existence of a state feedback $H^{\infty}$ controller using a form of linear matrix inequality(LMI). Furthermore, we show that the state feedback $H^{\infty}$ controllers can be obtained from solutions satisfying LMI.

• 전기전자학회논문지
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• 제18권4호
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• pp.517-522
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• 2014

본 논문은 임의의 네트워크 시간 지연이 존재하는 선형 다개체 시스템의 일치문제를 다룬다. 다개체 시스템의 상태일치를 위한 충분조건은 선형행렬방정식을 이용하여 제공된다. 또한, 제안한 충분조건아래에서 임의의 크기를 갖는 네트워크 지연이 존재하는 경우에도 일치에 도달할 수 있음을 증명한다. 마지막으로 제안한 결과의 유효성을 증명하기 위하여 수치 예제를 제공한다.

• 한국해양공학회지
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• 제26권3호
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• pp.20-25
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• 2012

In this paper, the authors propose a new approach to the control problem of marine vessels that are moored or controlled by actuators. The vessel control system is basically based on Dynamic Positioning System (DPS) technology. The main object of this paper is to obtain a more useful control design method for DPS. In this problem, the control allocation is a complication. For this problem, many results have been given and verified by other researchers using a two-step process, with the controller and control allocation design processes carried out individually. In this paper, the authors provide a more sophisticated design solution for this issue. The authors propose a new design method in which the controller design and control allocation problems are considered and solved simultaneously. In other words, the system stability, control performance, and allocation problem are unified by an LMI (linear matrix inequality) based on control theory. The usefulness of the proposed approach is verified by a simulation using a supply vessel model.

• 제어로봇시스템학회논문지
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• 제19권9호
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• pp.846-852
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• 2013

In this paper, the authors propose a new approach to control problem of the marine vessels which are moored or controlled by actuators. The vessel control problem in the specified area is called a DPS (Dynamic Positioning System). The main objective of this paper is to obtain more useful control design method for DPS. In this problem, a complicate fact is control allocation which is a numerical method for distributing the control signal to the controlled system. For this, many results have been given and verified by other researchers using two individual processes. It means that the controller design and control allocation design process are carried out individually. In this paper, the authors give more sophisticated design solution on this issue. In which the controller design and control allocation problem are unified by a robust controller design problem. In other word, the stability of the closed-loop system, control performance and allocation problem are unified by an LMI (Linear Matrix Inequality) constraint based on $H_2/H_{\infty}$ mixed design framework. The usefulness of proposed approach is verified by simulation with a supply vessel model and found works well.

• 제어로봇시스템학회논문지
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• 제20권1호
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• pp.6-11
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• 2014

Repetitive control is a specialized control scheme to track and/or attenuate a periodic reference trajectory and/or disturbance. Most researches about repetitive control have been performed in the frequency domain. Recently, several approaches to deal with repetitive control systems in the state space are developed by representing a q filter as a state-space equation. This paper presents a design method of a repetitive control system in the state space to satisfy $H_{\infty}$ performance. The overall system is composed of a plant, a repetitive controller, and a state-feedback controller, which can be converted to a standard form used in $H_{\infty}$ control. A LMI (Linear Matrix Inequality)-based stability condition is derived for fixed state-feedback gains. Under a given q filter, another LMI condition is derived to improve $H_{\infty}$ performance and is employed to find state-feedback gains by solving an optimization problem. Finally, to verify the feasibility of the proposed method, a numerical example is demonstrated.

• 한국지능시스템학회논문지
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• 제14권3호
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• pp.316-323
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• 2004

이 논문에서는 특이섭동 T-S 퍼지시스템의 $H_{\infty}$ 출력 궤환 제어기의 설계를 취급한다. 특이섭동 시스템에서 저속 부시스템과 고속 부시스템의 $H_{\infty}$ 노옴이 각각 ${\gamma}$ 보다 적다면 충분히 적은 ${\varepsilon}$>0에 대해서 특이섭동 퍼지시스템의 $H_{\infty}$ 노옴이 ${\gamma}$보다 적음을 증명한다. 이러한 사실을 이용하여 특이섭동 파라메터 ${\varepsilon}$과 무관한 선형 행렬부등식을 기반으로하는 제어기 설계법을 제시한다. 제시된 설계법의 효용성을 입증하기 위하여 수치예를 보여준다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제7권1호
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• pp.77-84
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• 2007

In this paper, Takagi-Sugeno (TS) fuzzy integral control is investigated to regulate the output voltage of an asymmetric half-bridge (AHB) DC/DC converter; First, we model the dynamic characteristics of the AHB DC/DC converter with state-space averaging method and small perturbation at an operating point. After introducing an additional integral state of the output regulation error, we obtain the $5^{th}$-order TS fuzzy model of the AHB DC/DC converter. Second, the concept of the parallel distributed compensation is applied to design the fuzzy integral controller, in which the state feedback gains are obtained by solving the linear matrix inequalities (LMIs). Finally, simulation results are presented to show the performance of the considered design method as the output voltage regulator and compared to the results for which the conventional loop gain method is used.

• 제어로봇시스템학회논문지
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• 제3권2호
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• pp.109-114
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• 1997

In this paper, we present an output feedback $H^\infty$controller design method and derive the sufficient condition of the bounded real lemma for linear systems with multiple delays in states. For state delayed systems, sufficient conditions for the existence $\kappa$-th order $H^\infty$controllers are given in terms of three linear matrix inequalities(LMIs). Furthermore, we show how to construct such controllers from the positive definite solutions of their LMIs and given an example to illustrate the validitiy of the proosed design procedure.

• 전자공학회논문지SC
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• 제40권5호
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• pp.326-332
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• 2003

본 연구에서는 상태변수에 시변 시간지연을 가진 선형시스템의 모델 차수축소를 취급한다. 이를 위하여 시간지연 시스템의 일반화 가제어성/가관측성 그래미안을 선형행렬 부등식의 해를 이용하여 정의하고 균형화된 상태공간 구현을 정의한다. 균형화된 상태공간 구현으로부터 상태변수론 절삭하여 차수축소된 시간지연 시스템을 구하고 모델 축소오차의 상한치를 제시한다. 수치예를 통하여 제시된 방법의 효용성을 입증한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년 학술대회 논문집 정보 및 제어부문
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• pp.220-222
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• 2006

This paper presents intelligent digital redesign method of global approach for hybrid state space fuzzy-model-based controllers. For effectiveness and stabilization of continuous-time uncertain nonlinear systems under discrete-time controller, Takagi-Sugeno(TS) fuzzy model is used to represent the complex system. And global approach design problems viewed as a convex optimization problem that we minimize the error of the norm bounds between nonlinearly interpolated lineal operators to be matched. Also, by using the bilinear and inverse bilinear approximation method, we analyzed nonlinear system's uncertain parts more precisely. When a sampling period is sufficiently small, the conversion of a continuous-time structured uncertain nonlinear system to an equivalent discrete-time system have proper reason. Sufficiently conditions for the global state-matching of the digitally controlled system are formulated in terms of linear matrix inequalities (LMIs). Finally, a T-S fuzzy model for the chaotic Lorentz system is used as an example to guarantee the stability and effectiveness of the proposed method.