• Title/Summary/Keyword: Weighted sensitivity function

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Robust controller design for RTP system using weighted mixed sensitivity minimization (하중 혼합감도함수를 이용한 RTP 시스템의 견실제어기 설계)

  • 이상경;오도창;박홍배
    • 제어로봇시스템학회:학술대회논문집
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    • 1997.10a
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    • pp.434-437
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    • 1997
  • In this paper, we present an $H^{\infty}$ controller design of RTP system satisfying robust stability and performance using weighted mixed sensitivity minimization. In industrial fields, RTP system is widely used for improving the oxidation and the annealing in semiconductor manufacturing process. The main control factors are temperature control of wafer and uniformity in the wafer. The control of temperature and uniformity has been solved by PI control method. We improve robust stability and performance of RTP system by the design of $H^{\infty}$ controller using the weighted mixed sensivity function. An example is proposed to show the validity of proposed method.d.

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A Study on the Design Method of a Continuous Time Deadbeat Controller (연속시간 유한정정제어기의 설계방법 고찰)

  • 김성열;이금원
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.326-326
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    • 2000
  • Continuous time system deadbeat controller(CdbC) has been studied mainly since 1992 especially by Japan researchers. They suggested delay elements. These elements stem from the finite Laplace Transform which is the starting point in deadbeat control system design in continuous time system. Every transfer function is established by these elements. From some conditions such as internal model stability and peasibility of a CdbC controller. unknown polynomials or coefficients can be calculated. In this paper, optimal pole placement of the closed loop system is suggested. From this. a CdbC controller with lower order can be obtained which attains the same level of weighted sensitivity function's H$_{\infty}$ norm used as a measure of the robustness property as existing CdbCs.

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A Design of $H_{\infty}$ Adaptive controller ($H_{\infty}$ 적응 제어기의 설계)

  • Park, Seung-Kyu;An, Ho-Kyun;Jang, Woo-Young
    • Proceedings of the KIEE Conference
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    • 1997.07b
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    • pp.679-681
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    • 1997
  • A $H_{\infty}$ adaptive controller is designed by using polynomial approach. The $H_{\infty}$ robust controllers for adaptive system were designed by Grimble. But they did not minimize the mixed sensitivity ra cost function which is the re sum of weighted sensitivity and complementary sensitivity terms Moreover pole placement is dependent of cost function. In this paper, the mixed sensitivity re cost function is minimized by employing the Youla parameterization and polynomial approach at the same time. And pole plaement is independent of weighting function.

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Coprime factor reduction of plant in $H{\infty}$ mixed sensitivity problem

  • Um, Tae-Ho;Oh, Do-Chang;Park, Hong-Bea;Kim, Soo-Joong
    • 제어로봇시스템학회:학술대회논문집
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    • 1995.10a
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    • pp.340-343
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    • 1995
  • In this paper, we get a reduced order controller in $H^{\infty}$ mixed sensitivity problem with weighting functions. For this purpose, we define frequency weighted coprime factor of plant in $H^{\infty}$ mixed sensitivity problem and reduce the coprime factor using the frequency weighted balanced truncation technique. The we design the controller for plant with reduced order coprime factor using J-lossless coprime factorization technique. Using this approach, we can derive the robust stability condition and achieve good performance preservation in the closed loop system with reduced order controller. And it behaves well in both stable plant and unstable plant.t.

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Design of Robust Load Frequency Controller using Mixed Sensitivity based $H_{\infty}$ norm (혼합강도 $H_{\infty}$ 제어기법을 이용한 강인한 부하주파수 제어기 설계)

  • 정형환;김상효;이정필;한길만
    • Journal of Advanced Marine Engineering and Technology
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    • v.24 no.3
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    • pp.88-98
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    • 2000
  • In this paper, a robust controller using $H_{\infty}$ control theory has been designed for the load frequency control of interconnected 2-area power system. The main advantage of the proposed $H_{\infty}$ controller is that uncertainties of power system can be included at the stage of controller design. Representation of uncertainties is modeled by multiplicative uncertainly. In the mixed sensitivity problems, disturbance attenuation and uncertainty of the system is treated simultaneously. The robust stability and the performance of model uncertainties are represented by frequency weighted transfer function. The design of load frequency controller for each area was based on state-space approach. The comparative computer simulation results for the proposed controller and the conventional techniques such as the optimal control and the PID one were analyzed at the additions of various disturbances. Their deviation magnitude of frequency and tie line power flow at each area were mainly evaluated. Also the testing results of robustness for the cases that the perturbations of the all parameters of power system were amounted to about 20% were introduced. It was approved that the resultant performances of the proposed $H_{\infty}$ controller with mixed sensitivity were more robust and stable than the one of conventional controllers.

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The Subjectively Weighted Linear Utility Model using Bayesian Approach (베이지안 기법을 이용한 주관적 가중선형효용모형)

  • 김기윤;나관식
    • Journal of the Korean Operations Research and Management Science Society
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    • v.19 no.3
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    • pp.111-129
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    • 1994
  • In this study, we develope a revised model as well as application of decision problem under ambiguity based on the subjectively weighted linear utility medel. Bayes'rule is used when there are ambiguous probabilities on a decision problem and test information is available. A procedure for assessing the ambiguity aversion function is also presented. Decision problem of chemical corporation is used for an illustration of the application of the subjectively weighted linear utility model using Bayesian approach. We present the optimal decisiond using newly developed model. We also perform the sensitivity analysis to assure ourselves about the conclusion we obtianed on degree of ambiguity aversion due to characterize parameter of subjectively weighted linear utility model.

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Robust $H^{2}$ Controller Design of RTP Systems (RTP 시스템의 견실$H^{2}$제어기 설계)

  • 이상경;김종해박홍배
    • Proceedings of the IEEK Conference
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    • 1998.10a
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    • pp.409-412
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    • 1998
  • In this paper, we present an $H^2$ controller design of RTP(rapid thermal processing) systems satisfying robust stability and performance using weighted mixed sensitivity minimization. In industrial fields, RTP system is widely used for improving the oxidation and the annealing in semiconductor manufacturing process. The main control factors are temperature control of wafer and uniformity has been solved by PID control method. Because the reference inputs of RTP are ramp, we improve performance of RTP system by the design of $H^2controller$ using the weighted mixed sensitivity function. Also we compare $H^2controller$ with PID controller in terms of performance. An example is proposed to show the validity of proposed method.

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$H^{\infty}$ Optomal Control Using the Lagrange Multiplier Method (Lagrange 승산자 방법을 이용한$H^{\infty}$최적제어)

  • 전재완;윤한오;박홍배;김수중
    • 제어로봇시스템학회:학술대회논문집
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    • 1991.10a
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    • pp.40-45
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    • 1991
  • This paper deals with the design of feedback controllers which minimize the $H^{\infty}$-norm of the weighted sensitivity function. Using the Lagrange multiplier method and the Nevanlinna-Pick interpolation theory, an algorithm which stabilizes a plant and makes the output to track the reference signal is proposed..

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A Study on the $H_{\infty}$ Robust Controller for Adaptive Control-polynomial approach (적응제어를 위한 $H_{\infty}$ 강인제어기의 설계-다항식 접근방법)

  • Park, Seung-Kyu
    • Proceedings of the KIEE Conference
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    • 1996.07b
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    • pp.936-938
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    • 1996
  • The $H_{\infty}$ robust controller is designed for on-line adaptive control application by using polynomial approach. The $H_{\infty}$ robust controllers for adaptive system were designed first by Grimble. But they have a problem that two minimum costs can exist and did not minimize the conventional $H_{\infty}$ cost function which is the $H_{\infty}$ sum of weighted sensitivity and complementary sensitivity terms. In this paper, the two minimum costs problem can be avoided and the conventional $H_{\infty}$ cost function is minimized by employing the Youla parameterization and polynomial approach at the same time. In addition pole placement is possible without any relation with weighting function.

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The Realization of State-Space Digital Filters with Minimum Output Error Variance by Weighted Function (가중함수에 의한 최소 출력오차 분산을 갖는 상태공간 디지틀 필터 실현)

  • 김정화;정찬수
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.17 no.9
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    • pp.909-917
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    • 1992
  • This paper proposes the realization of state-space digital filters with minimum output error variance. The algorithm is transforms of controllability and observability gramian in linear time invariant systems by weighted function and can improve performance of the digital filters by reducing the put error variance for state space coeffient variation. A numerical example shows that algorithm structure has much lower output error variance than that of other four structures(canonical, parallel, statistical sensitivity, balanced).

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