• 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.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제2권1호
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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.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제3권1호
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• pp.58-65
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• 2003

In this paper, a new model, which is a Takagi-Sugeno fuzzy model, for mobile robot is presented. A controller, consisting of two loops the one of which is the inner state feedback loop designed for stability and the outer loop is a PI controller designed for tracking the reference input, is suggested. Because the robot dynamics is nonlinear, it requires the controller to be insensitive to the nonlinear term. To achieve this objective, the model is developed by well known T-S fuzzy model. The design algorithm of inner state-feedback loop is regional pole-placement. In this paper, regions, for which poles of the inner state feedback loop are lie in, are formulated by LMI's. By solving these LMI's, we can obtain the state feedback gains for T-S fuzzy system. And this paper shows that the PI controller is equivalent to the state feedback and the cost function for reference tracking is equivalent to the LQ(linear quadratic) cost. By using these properties, it is also shown in this paper that the PI controller can be obtained by solving the LQ problem.

• Journal of Electrical Engineering and Technology
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• 제7권3호
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• pp.436-442
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• 2012

This paper develops a design methodology of a decentralized fuzzy load-frequency controller for a large-scale nonlinear power system with valve position limits on governors. The concerned system is locally exactly modeled in Takagi-Sugeno's form. Sufficient design condition for uniform ultimate boundedness of the closed-loop system is derived based on the overlapping decomposition. Convergence of all incremental frequency deviations to zero is also investigated. A simulation result is provided to visualize the effectiveness of the proposed technique.

• 한국지능시스템학회논문지
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• 제14권3호
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• pp.298-303
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• 2004

본 논문은 임의의 입력지연을 갖는 Takagi-Sugeno (T-S) 퍼지 시스템의 관측기 기반 출력궤환 제어 시스템을 논의한다. 설계된 연속시간 T-S 퍼지 관측기 시스템을 영차의 샘플/홀드 함수를 이용하여 이산시간 관측기를 설계한다. 이때 플랜트와 관측기의 출력에러가 제어기를 통하여 궤환되기 때문에 이산화 과정에서 발생한 에러를 보정할 수 있다. 여기에서 시스템의 제어 입력은 임의로 변화하는 유한개의 상태를 갖는 마코프 확률과정으로 표현한다. 생성된 시스템의 확률적 안정 가능성 조건은 선형 행렬 부등식의 형태로 표현한다. 이러한 결과를 2자유도 헬리콥터의 모델에 대한 모의실험을 통하여 효용성을 확인한다.

• 한국지능시스템학회논문지
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• 제22권4호
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• pp.441-447
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• 2012

본 논문은 무인 잠수정(Autonomous underwater vehicles: AUVs)의 타카기-수게노 (Takagi-Sugeno: T-S) 퍼지 모델 기반 $H_{\infty}$ 제어기 설계 기법을 제안한다. 설계 기법은 외란을 갖는 무인 잠수정의 깊이 제어 성능을 보장하는 안정성 있는 제어기 설계에 초점을 맞춘다. 비선형 무인 잠수정 시스템은 Sector nonlinearity 기법을 이용하여 T-S 퍼지 시스템으로 모델링된다. 리아푸노프(Lyapunov) 함수를 이용해 제어 성능을 보장하는 선형 행렬 부등식(linear matrix inequality: LMI) 형태의 $H_{\infty}$ 제어기 설계 조건을 유도한다. 성공적인 무인 잠수정의 깊이 제어를 위해 선형 행렬 부등식에 심도각과 피치각의 제한 조건을 고려한다. 시뮬레이션을 통해 제안된 기법의 성능을 검증한다.

• 한국지능시스템학회논문지
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• 제21권4호
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• pp.423-429
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• 2011

본 논문은 고분자 전해질 연료전지 시스템(PEMFC)을 위한 비선형 상호결합 시스템의 분산 퍼지 제어기 설계 기법을 제안한다. 이를 위해 연료전지 시스템의 비선형성을 확인하고, Takagi-Sugeno (T-S) 퍼지 모델링을 통하여 비선형 시스템을 퍼지 모델로 변환한다. 변환된 퍼지 모델을 기반으로 퍼지 관측기를 설계하고 퍼지 시스템을 안정화 시킬 수 있는 분산 퍼지 제어기를 설계한다. 폐루프 시스템의 안정도 조건을 선형 행렬 부등식으로 나타내고, 부등식을 이용하여 제어기의 이득값을 구한다. 마지막으로, 모의실험을 통하여 제어기의 효용성을 평가한다.

• Journal of Power Electronics
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• 제7권3호
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• pp.238-245
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• 2007

This paper considers the problem of regulating the output voltage of a current doubler rectified asymmetric half-bridge (CDRAHB) DC/DC converter via fuzzy integral control. First, we model the dynamic characteristics of the CDRAHB converter with the state-space averaging method, and after introducing an additional integral state of the output regulation error, we obtain the Takagi-Sugeno (TS) fuzzy model for the augmented system. Second, the concept of parallel distributed compensation is applied to the design of the TS fuzzy integral controller, in which the state feedback gains are obtained by solving the linear matrix inequalities (LMIs). Finally, numerical simulations of the considered design method are compared to those of the conventional method, in which a compensated error amplifier is designed for the stability of the feedback control loop.

• International Journal of Control, Automation, and Systems
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• 제3권3호
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• pp.411-418
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• 2005

This paper discusses an output-tracking control design method for Takagi-Sugeno fuzzy systems with parametric uncertainties. We first represent the concerned system as a set of uncertain linear systems. The tracking problem is then converted into a stabilization problem thereby leading to a more feasible control design procedure. A sufficient condition for robust practical output tracking is derived in terms of a set of linear matrix inequalities. A numerical example for a flexible-joint robot-arm model has been demonstrated, to convincingly show effectiveness of the proposed system modeling and control design.

• 전기학회논문지
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• 제63권8호
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• pp.1080-1084
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• 2014

This paper addresses a design technique for formation tracking controllers of discrete-time Takagi-Sugeno fuzzy multi-agent systems based on consensus. The interconnection topology among the agents is expressed as a digraph. The design condition is represented in terms of linear matrix inequalities. Numerical example demonstrates the effectiveness of the proposed method.