• International Journal of Control, Automation, and Systems
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• 제4권4호
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• pp.506-515
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• 2006

This paper studies an intelligent digital control for nonlinear systems with multirate sampling. It is worth noting that the multirate control design is addressed for a given nonlinear system represented by Takagi-Sugeno (T-S) fuzzy models. The main features of the proposed method are that i) it is provided that the sufficient conditions for stabilization of the discrete-time T-S fuzzy system in the sense of Lyapunov stability criterion, which is can be formulated in the linear matrix inequalities (LMIs); and ii) the stability properties of the trivial solution of the digital control system can be deduced from that of the solution of its discretized versions. An example is provided for showing the feasibility of the proposed method.

• 한국정보통신학회논문지
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• 제6권1호
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• pp.1-5
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• 2002

디지털 제어시스템을 설계하려면, 먼저 아날로그 시스템을 설계한 후, 이산화하여 디지털 시스템을 설계한다. 본 논문에서는 최적 디지털 제어기의 선계에 샘플치 제어이론을 적용한다. 특히, 아날로그 제어기들의 멀티레이트 이산화에 Η$_2$최적화를 이용한다. 멀티레이트 구조상 인과성 제약을 갖는 멀티레이트 Η$_2$최적화를 통해 해를 얻는다. 설계 예제를 통해, 기존 이산화 방법과 비교하여, 멀티레이트 설계방법의 우수성을 확인한다.

• 제어로봇시스템학회논문지
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• 제8권12호
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• pp.1004-1013
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• 2002

A multirate state feedback control (MRSFC) method is proposed for systems sensitive to disturbance and noise based on the multirate estimator design using current estimator. MRSFC updates the controller output slower than the measurement sampling fiequency of system output by a lifting factor $R=T_c/T_s$ The closed-loop MRSFC system is less sensitive to disturbance and noise due to filtering effect than the conventional single-rate control system The multirate estimator gain can be obtained by solving a conventional pole placement problem such that MRSFC has the same spectrum of eigenvalues in the s-plane as the single-rate control. We applied the proposed multirate state feedback controller to a galvanometer servo system Simulation and experimental results show that settling and tracking performances are improved compared with a conventional single-rate pole placement control (PPC).

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.190-190
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• 2000

This paper presents a multirate state feedback control (MRSFC) method for systems sensitive to disturbance and noise based on the multirate estimator design using the current estimator. MRSFC updates the controller output slower than the measurement sampling frequency of system output by a lifting factor R=T$\sub$c//T$\sub$s/. The closed-loop MRSFC system is less sensitive to disturbance and noise due to filtering effect than the conventional single-rate control system. The multirate estimator gain is obtained from solving a conventional pole placement problem such that MRSFC has the same spectrum of eigenvalues in the s-plane as the single-rate control. We applied the proposed multirate state feedback controller to a galvanometer servo system. Simulation and experimental results show that settling and tracking performances are improved compared with a conventional single-rate pole placement control (PPC).

• 제어로봇시스템학회논문지
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• 제12궈1호
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• pp.54-59
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• 2006

The smart space is composed of the wire and/or wireless network, multi-sensor-based environment, and many various controllers. For the smart space, this paper presents a new design method of multirate digital decentralized controller using the intelligent digital redesign technique. In specific, the proposed method is based on the delta-operator and the multirate sampling and takes the form of the LMIs. To shows the feasibility of the suggested method, the computer simulations for Heating, ventilating, and ai. conditioning (HVAC) system are provided.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.708-710
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• 2004

This paper studies a multirate sampled-data control for LTI systems by using the digital redesign (DR) method. In this note, to well tackle the problem associated with both the state matching and the stabilization, our nobel strategy is to minimize the linear quadratic cost function. The main features of the proposed method are that i) the delta-operator-based descretization method is applied to improve the state-matching performance in the fast sampling limit and/or the large input multiplicity; ii) the proposed multirate control scheme can improve the state-matching performance in the long sampling limit; iii) some sufficient conditions that guarantee the stability of the closed-loop discrete-time system and provide a guarantee cost for the cost function can be formulated in the LMIs format; and iv) an optimal sampled-data controller in the sense of minimizing the upper bound of the cost function is also given by means of an LMI optimization procedure.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2001년도 추계종합학술대회
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• pp.271-274
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• 2001

본 논문에서는 최적 디지털 제어기의 설계에 샘플치 제어이론을 적용한다. 특히, 아날로그 제어기들의 멀티레이트 이산화에 H$_2$최적화를 이용한다. 멀티레이트 구조상 인과성 제약을 갖는 멀티레이트 H$_2$최적화를 통해 해를 얻는다. 설계 예제를 통해, 기존 이산화 방법과 비교하여, 멀티레이트 설계방법의 우수성을 확인한다.

• 한국지능시스템학회논문지
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• 제15권6호
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• pp.765-770
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• 2005

This paper presents a new intelligent digital redesign (IDR) method via the compensated bilinear transformation to design the digital controller such that the digital fuzzy system is equivalent to the analog fuzzy system in the sense of the state-matching. This paper especially consider a multirate control scheme with a predictive feature, where the digital control input is held constant N times between the sampling points. More precisely, the multirate control scheme is proposed that utilizes a numerical integration scheme to approximately predict the current state from the state measured at the sampling points, the delayed measurements. For this system, the IDR conditions incorporated with stabilizability in the format of the linear matrix inequalities (LMIs) are derived. The superiority of the proposed technique is convincingly visualized through a numerical example.

• 융합신호처리학회논문지
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• 제4권4호
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• pp.47-51
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• 2003

디지털제어에 잘 사용되어 온 유한정정제어를 연속계에 적용하기는 연속계의 점근성 때문에 어려운 것으로 알려져 있다. 그러나 유한 Laplace변환을 전달함수에 적용하고 여기에 정정조건을 적용하여 제어기를 설계한 연속계 유한정정제어기(CDBC, Continuous-time Deadbeat Controller)에 대해서 연구가 되고 있다. 이에 따라 지연요소가 전달함수에 사용되어 정정을 위한 차수 및 보간조건이 유도되어 제어기가 설계되거나, 디지털 유한정정제어기를 설계하고 이를 연속계 제어기로 변환하기 위해 평활요소로 사용하여 CDBC를 구성하기도 한다. 본 논문에서는 다중 샘플링을 적용하여 제어기와 출력귀환루프의 샘플링 속도를 달리하였으며, 2차 평활요소를 디지털 유한정정제어기에 사용한 CDBC를 연구한다. 이러한 다중 샘플링은 샘플링 주기 동안에 제어루프를 또 샘플링하여 전체적인 출력응답을 개선할 수 있다. 제어기는 직렬 적분 보상기를 전향경로에 배치하고 지역 귀환보상기를 귀환 루프에 도입한다. Matlab Simulink을 사용하여 시뮬레이션을 한다.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2005년도 추계학술대회 학술발표 논문집 제15권 제2호
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• pp.91-94
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• 2005

This paper presents a new linear- matrix- inequality- basedintelligent digital redesign (LMI-based IDR) technique to match he states of the analog and the digital control systems at the intersampling instants as well as the sampling ones. The main features of the proposed technique are: 1) the multirate control is employed, and the control input is changed N times during one sampling period; 2) The proposed IDR technique is based on the compensated bilinear transformation.