• Title, Summary, Keyword: nonlinear control

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최신 비선형 pH제어 방법의 실험적 비교

  • 천일근;유성덕;이지태
    • 제어로봇시스템학회:학술대회논문집
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    • pp.327-330
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    • 1989
  • Two recent nonlinear control methods of nonlinear geometric method and nonlinear optimal control method are applied to a pH control system with severe nonlinear characteristics. Simulations and experiments show that their performances are very good and robust for various realistic situations such as model parameter mismatches.

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A nonlinear structural experiment platform with adjustable plastic hinges: analysis and vibration control

  • Li, Luyu;Song, Gangbing;Ou, Jinping
    • Smart Structures and Systems
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    • v.11 no.3
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    • pp.315-329
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    • 2013
  • The construction of an experimental nonlinear structural model with little cost and unlimited repeatability for vibration control study represents a challenging task, especially for material nonlinearity. This paper reports the design, analysis and vibration control of a nonlinear structural experiment platform with adjustable hinges. In our approach, magnetorheological rotary brakes are substituted for the joints of a frame structure to simulate the nonlinear material behaviors of plastic hinges. For vibration control, a separate magnetorheological damper was employed to provide semi-active damping force to the nonlinear structure. A dynamic neural network was designed as a state observer to enable the feedback based semi-active vibration control. Based on the dynamic neural network observer, an adaptive fuzzy sliding mode based output control was developed for the magnetorheological damper to suppress the vibrations of the structure. The performance of the intelligent control algorithm was studied by subjecting the structure to shake table experiments. Experimental results show that the magnetorheological rotary brake can simulate the nonlinearity of the structural model with good repeatability. Moreover, different nonlinear behaviors can be achieved by controlling the input voltage of magnetorheological rotary damper. Different levels of nonlinearity in the vibration response of the structure can be achieved with the above adaptive fuzzy sliding mode control algorithm using a dynamic neural network observer.

Control of complex distillation configuration (복합 증류계의 제어)

  • 한명완;박선원
    • 제어로봇시스템학회:학술대회논문집
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    • pp.742-748
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    • 1993
  • The dynamics and control of two complex column configurations (sidestream column with stripper; prcfractionater/sidestream column configuration), which are multivariable interacting and nonlinear, have been studied. A new control scheme developed by Hanand Park(1993) to deal with the nonlinear and multivariable nature of distillation processes has been applied to these complex distillation configurations. The control scheme incorporates a nonlinear wave model into a generic model control framework. An observer based on the nonlinear wave model is used to determine the profile positions of distillation column sections. The control scheme enables tight control of the profile position of each column section that leads to fast stabilization of product compositions.

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Nonlinear Hydraulic System Control Using Fuzzy PID Control Technique (퍼지 PID 제어 기법을 이용한 비선형 유압시스템의 제어)

  • 박장호;김종화;류기석
    • 제어로봇시스템학회:학술대회논문집
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    • pp.69-69
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    • 2000
  • Control systems using a hydraulic cylinder as an actuator are modeled to a nonlinear system owing to varying of moments and nonlinearities of hydraulic itself. In this paper, we want to control nonlinear hydraulic systems by adopting the fuzzy PID control technique which include nonlinear time varying control parameters. To do this, we propose the design method of fuzzy Pm controller and in order to assure effectiveness of fuzzy PID controller, computer simulations were executed for the control system.

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Comparative Performance Evaluation of Nonlinear Controllers for Longitudinal Control in a Vehicle Platooning (군집주행의 종방향 제어를 위한 비선형 제어기 성능 비교 평가)

  • 전성민;최재원;김영호
    • 제어로봇시스템학회:학술대회논문집
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    • pp.218-218
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    • 2000
  • Advanced Vehicle Control Systems(AVCS) is one of the key elements in Intelligent Transportation Systems(ITS). This paper considers the problem of longitudinal control in vehicle platoon on a straight lane of a highway. In a very simplified situation, longitudinal vehicle dynamics contains many nonlinear elements. The nonlinear characteristics are mainly composed of an engine, a torque converter, and a drag force. In this paper, sliding control, one of nonlinear control methods, is applied to longitudinal automated vehicle control for platooning. Output feedback linearization is also simulated for comparison with the sliding control. Simulations for comparative study for the adopted controllers such as sliding control and output feedback linearization are peformed under the same conditions. This Paper aims at clarifying the characteristics of sliding control and output feedback linearization.

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A Study on Nonlinear PID Controller Design Using a Cell-Mediated Immune Response (세포성 면역 반응을 이용한 비선형 PID 제어기 설계에 관한 연구)

  • Park Jin-Hyun;Choi Young-Kiu
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.52 no.5
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    • pp.259-267
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    • 2003
  • In this paper, we propose a nonlinear variable PID controller using a cell-mediated immune response. An immune feedback response is based on the functioning of biological T-cells. An immune feedback response and P-controller of conventional PID controllers resemble each other in role and mechanism. Therefore, we extend immune feedback mechanism to nonlinear PE controller. And in order to choose the optimal nonlinear PID controller games, we also propose the on-line tuning algorithm of nonlinear functions parameters in immune feedback mechanism. The trained parameters of nonlinear functions are adapted to the variations of the system parameters and any command velocity. And the adapted parameters obtained outputs of nonlinear functions with an optimal control performance. To verify performances of the proposed control systems, the speed control of nonlinear BC motor is performed. The simulation results show that the proposed control systems are effective in tracking a command velocity under system variations.

Design of IMC for Nonlinear Systems by Using Adaptive Neuro-Fuzzy Inference System (뉴로 퍼지 시스템을 이용한 비선형 시스템의 IMC 제어기 설계)

  • Kim, Sung-Ho;Kang, Jung-Kyu
    • Journal of Institute of Control, Robotics and Systems
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    • v.7 no.11
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    • pp.958-961
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    • 2001
  • Control of Industrial processes is very difficult due to nonlinear dynamics, effect of disturbances and modeling errors. M.Morari proposed Internal Model Control(IMC) system that can be effectively applied to the systems with model uncertainties and time delays. The advantage of IMC is their robustness with respect to a model mismatch and disturbances. But it is difficult to apply for nonlinear systems. ANFIS(Adaptive Neuro-Fuzzy Inference System) which contains multiple linear models as consequent part is used to model nonlinear systems. Generally, the linear parameters in ANFIS can be effectively utilized to control a nonlinear systems. In this paper, we propose new ANFIS-based IMC controller for nonlinear systems. Numerical simulation results show that the proposed control scheme has good performances.

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Adaptive Fuzzy Output Feedback Control based on Observer for Nonlinear Heating, Ventilating and Air Conditioning System

  • Baek, Jae-Ho;Hwang, Eun-Ju;Kim, Eun-Tai;Park, Mi-gnon
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.9 no.2
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    • pp.76-82
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    • 2009
  • A Heating, Ventilating and Air Conditioning (HVAC) system is a nonlinear multi-input multi-output (MIMO) system. This system is very difficult to control the temperature and the humidity ratio of a thermal space because of complex nonlinear characteristics. This paper proposes an adaptive fuzzy output feedback control based on observer for the nonlinear HVAC system. The nonlinear HVAC system is linearized through dynamic extension. State observers are designed for estimating state variables of the HVAC system. Fuzzy systems are employed to approximate uncertain nonlinear functions of the HVAC system with unavailable state variables. The obtained controller compares with an adaptive feedback controller. Simulation is given to demonstrate the effectiveness of our proposed adaptive fuzzy method.

Direct Gradient Descent Control and Sontag's Formula on Asymptotic Stability of General Nonlinear Control System

  • Naiborhu J.;Nababan S. M.;Saragih R.;Pranoto I.
    • International Journal of Control, Automation, and Systems
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    • v.3 no.2
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    • pp.244-251
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    • 2005
  • In this paper, we study the problem of stabilizing a general nonlinear control system by means of gradient descent control method which is a dynamic feedback control law. In this method, the general nonlinear control system can be considered as an affine nonlinear control systems. Then by using Sontag's formula we investigate the stability (asymptotic) of the general nonlinear control system.

Adaptive Nonlinear Guidance Considering Target Uncertainties and Control Loop Dynamics (목표물의 불확실성과 제어루프 특성을 고려한 비선형 적응 유도기법)

  • 좌동경;최진영;송찬호
    • Journal of Institute of Control, Robotics and Systems
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    • v.9 no.4
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    • pp.320-328
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    • 2003
  • This paper proposes a new nonlinear adaptive guidance law. Fourth order state equation for integrated guidance and control loop is formulated considering target uncertainties and control loop dynamics. The state equation is further changed into the normal form by nonlinear coordinate transformation. An adaptive nonlinear guidance law is proposed to compensate for the uncertainties In both target acceleration and control loop dynamics. The proposed law adopts the sliding mode control approach with adaptation fer unknown bound of uncertainties. The present approach can effectively solve the existing guidance problem of target maneuver and the limited performance of control loop. We provide the stability analyses and demonstrate the effectiveness of our scheme through simulations.