• Title, Summary, Keyword: Smith controller

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New Smith Predictor Controller Design Using a Disturbance Observer (외란 관측기를 이용한 새로운 스미스 예측제어기 설계)

  • Lee, Soon-Young;Yang, Dae-Geun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.9 no.8
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    • pp.1730-1734
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    • 2005
  • In this paper, a new Smith predictor controller for a disturbance adding to input side of a time delay plant is proposed. A disturbance observer is obtained to estimate an input disturbance and the new Smith predictor controller to eliminate the effects of a disturbance is designed using the disturbance observer. As a result, the proposed Smith predictor controller can make a steady state error for step input disturbance zero quickly. The effectiveness and the improved performance of the proposed system are verified by computer simulation.

Design of Hybrid Smith-Predictor Fuzzy Controller Using Reduction Model (축소 모델을 이용한 하이브리드 스미스 퍼지 제어기 설계)

  • Cho, Joon-Ho;Hwang, Hyung-Soo
    • Journal of Institute of Control, Robotics and Systems
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    • v.13 no.5
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    • pp.444-451
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    • 2007
  • In this paper, we propose an improved reduction model and a reduction model-based hybrid smith-predictor fuzzy controller. The transient and steady-state responsed of the reduction model was evaluated. In tuning the controller, the parameters of PID and the factors fuzzy controllers were obtained from the reduced model and by using genetic algorithms, respectively. Simulation examples demonstrated a better performance of the proposed controller than conventional ones.

Design of Controller using Smith Predictor in the Distributed control system including time-delay (시간 지연이 존재하는 분산 제어 시스템에서 Smith predictor를 이용한 제어기의 설계)

  • Cho, Duk-Young;Park, Eik-Dong;Huh, Uk-Youl
    • Proceedings of the KIEE Conference
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    • pp.2317-2319
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    • 2000
  • This paper presents a feedback controller for compensation time delay in the distributed control systems. In using network, controllers and sensors are distributed on a communications network, there exist time delays on communication lines between the system components. So, we deal with the controller using Smith predictor controller design issue for such systems. Particularly compensated for the time delay of the plant or controller involved integrator using Modified Smith predictor. Simulation and the results show the good performance for the modified Smith predictor control systems.

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Design of Cascade Controller With Structure of Smith - Predictor (스미스 예측기 구조를 갖는 Cascadede 제어기 설계)

  • Cho, Joon-Ho;Lee, Won-Hyok;Hwang, Hyung-Soo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.57 no.8
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    • pp.1447-1453
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    • 2008
  • In this paper, we proposed to improve performance of the design of a cascade controller with the smith-predictor structure. The parameters of controller in the inner loop are determined to minimize the integral of time multiplied by the absolute value of error (ITAE) value of performance Index. The controller of outer loop and parameters of Smith-Predictor can be obtain using reduction model. The model reduction is considered that it is the transient response and the steady-state response through the use of nyquist curve. Simulation examples are given to show the better performance of the proposed method than conventional methods.

Model Reduction Method and Optimized Smith Predictor Controller Design using Reduced Model (축소모델을 이용한 최적화된 Smith Predictor 제어기 설계)

  • 최정내;조준호;이원혁;황형수
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.52 no.11
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    • pp.619-625
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    • 2003
  • We proposed an optimum PID controller design method of the Smith Predictor It can be applied to various processes. The real process is approximated via the second order plus time delay model (SOPTD) whose parameters are specified through a model reduction algorithm. We already proposed a new model reduction method that considered four point in the Nyquist curve to reduced the steady state error between the real process model and the reduced model using the gradient decent method and the genetic algorithms. In addition, the Smith predictor is used to compensate time delay of the real process model. In this paper, the new optimum parameter tuning algorithm for PID controller of the Smith Predictor is proposed through ITAE as performance index. The Simulation results show the validity and improvement of performance for various processes.

Design of rule based expert controller for time delay systems (지연시간을 갖는 계통의 성능 향상을 위한 지식기반 전문가 제어기 설계)

  • 박귀태;이기상;김성호;박태홍;고응렬
    • 제어로봇시스템학회:학술대회논문집
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    • pp.117-121
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    • 1990
  • The control process involving pure time delays presents a continuing challenge to the control system engineer. The nonlinear nature of the delay which can be introduced into the system make the use of conventional control algorithms a poor prospect. The Smith Predictor was developed to alleviate this problem. Unfortunately the quality of control achieved with the Smith Predictor is known to be sensitive to modelling errors. Only recently have researchers attempted to quantify the Smith Predictor controller's robustness to modelling errors. In several studies stability boundaries were plotted as functions of errors in parameters. But the research results address the question of performance of Smith Predictor controllers, In this paper, the Rule based Expert Systems for performance improvement of the Smith Predictor controller are developed.

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Smith-Predictor Controller Design Using New Reduction Model (새로운 축소 모델을 이용한 Smith-Predictor 제어기 설계)

  • Choi Jeoung-Nae;Cho Joon-Ho;Hwang Hyung-Soo
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.52 no.1
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    • pp.9-15
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    • 2003
  • To improve the performance of PID controller of high order systems by model reduction, we proposed two model reduction methods. One, Original model with two point $({\angle}G(jw)=\;-{\pi}/2,\;-{\pi})$ in Nyquist curve used gradient base method and genetic algorithm. The other, Original model without two point$({\angle}G(jw)=\;-{\pi}/2,\;-{\pi})$in Nyquist curve used to add very small dead time. This method has annexed very small dead time on the base model for reduction, and we remove it after getting the reduced model, and , we improved Smith-predictor for a dead-time compensator using genetic algorithms. This method considered four points$({\angle}G(jw)=0,\;-\pi/2,\;-\pi,\;-3\pi/2)$ in the Nyquist curve to reduce steady state error between original and reduced model. It is shown that the proposed methods have more performance than the conventional method.

Design of Hierarchical Controller for Satisfaction of Multiple Performance (다양한 성능 만족을 위한 계층적 제어기 설계)

  • Cho, Joon-Ho
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.2
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    • pp.396-406
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    • 2007
  • In this paper, we proposed development of improved model reduction and design of hierarchical controller using reduction model. The model reduction is considered that it is the transient response and the steady-state response through the use of nyquist curve. The hierarchical controller selected tuning of PID controller to ensure specified gain and phase margin and hybrid smith-predictor fuzzy controller using reduction model. Simulation examples are given to show the better performance of the proposed method than conventional methods.

PI Control with the Smith Predictive Controller for a Variable Speed Refrigeration System

  • Hua, Li;Choi, Jeong-Pil;Jeong, Seok-Kwon;Yang, Joo-Ho;Kim, Dong-Gyu
    • International Journal of Air-Conditioning and Refrigeration
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    • v.15 no.3
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    • pp.129-136
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    • 2007
  • In this paper, we suggest PI control with the Smith predictive controller to improve transient response of a variable speed refrigeration system (VSRS). As the refrigeration system has long dead time inherently, it is difficult to get fast responses of super-heat and reference temperature. We incorporated the Smith predictive controller into PI to compensate the effect of the long dead time of the system. At first, we introduced the decoupling model of the system to control capacity and superheat simultaneously and independently. Next, we designed the predictive controller of the superheat based on PI control law. Finally, the control performance by the proposed method was investigated through some numerical simulations and experiments. The results of the simulations and experiments showed that the proposed PI control with the predictive controller could obtain acceptable transient behaviour for the system.

Design of the Controllers for the Improved Response of Time Delay Systems (시간지연 시스템의 응답특성 개선을 위한 제어기 설계)

  • Lee, Suk-Won;Yang, Seung-Hyun
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.19 no.7
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    • pp.15-19
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    • 2005
  • The practical control problems for the lime-delay system is considered. The delay-free characteristics of the Smith Predictor is available only when both the process and it's model are exactly matched. So it does not used widely in practical industrial processes. In this paper, using the 2nd-order plus dead time model in place of the plant model of the Smith Predictor, the proposed controller shows the improved performance in case of the very long time delay. And the range of integral constant of the PI controller is also proposed.