Wen-Jer Chang

National Taiwan Ocean University, Keelung, Taiwan, Taiwan

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Publications (96)73.25 Total impact

  • Wen-Jer Chang · Feng-Ling Hsu
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    ABSTRACT: This paper investigated the multiple performance constrained sliding mode fuzzy control problem for continuous-time stochastic nonlinear systems with multiplicative noises. The stochastic nonlinear systems considered in this paper are represented by Takagi-Sugeno (T-S) fuzzy models with a bilinear consequent part. To simultaneously satisfy stability, passivity and variance constraints, sufficient conditions are derived in terms of linear matrix inequalities based on Lyapunov theory. By solving the corresponding sufficient conditions, a parallel distributed compensation based fuzzy controller is obtained to ensure the stability of the closed-loop nonlinear systems subject to variance and passivity performance constraints. The main contribution of this paper is a sliding mode fuzzy controller developed such that the considered multiple performance constraints can be satisfied for the T-S fuzzy systems with a bilinear consequent part. Finally, a numerical example for controlling a ship steering system is provided to demonstrate the validity and effectiveness of the proposed sliding mode fuzzy control method.
    No preview · Article · Jan 2016 · Information Sciences
  • Wen-Jer Chang · Po-Hsun Chen · Cheung-Chieh Ku
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    ABSTRACT: In this study, a novel multi-objective sliding mode fuzzy control technique is presented for a class of discrete-time non-linear stochastic systems that are represented by Takagi-Sugeno (T-S) fuzzy models. Subject to variance and passivity constraints, parallel distributed compensation based sliding mode fuzzy control approach is investigated for the discretetime T-S fuzzy models. Combining Lyapunov theory, passivity theory and covariance theory, sufficient conditions are derived to satisfy stability, passivity and variance constraints. The iterative linear matrix inequality algorithm is employed in this study to solve these sufficient conditions. The contribution of this study is to develop a novel sliding mode fuzzy control method such that the closed-loop discrete-time non-linear stochastic system achieves passivity constraint and individual state variance constraints, simultaneously. At last, the simulations of controlling a discrete-time non-linear ship steering system are given in a numerical example to demonstrate the effectiveness and usefulness of proposed sliding mode fuzzy control methodology.
    No preview · Article · Jul 2015 · IET Control Theory and Applications
  • Wen-Jer Chang · Che-Pin Kuo · Cheung-Chieh Ku
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    ABSTRACT: This paper provides the criterion for discussing stability analysis and synthesis of a class of complex nonlinear systems represented by Takagi–Sugeno fuzzy models with multiplicative noise. In the consequent part of the T–S fuzzy models, the Itô’s stochastic differential equations are introduced to represent the linear subsystems with multiplicative noise. Under the concept of imperfect premise matching, a novel fuzzy controller is designed without limitation of sharing the same membership function of fuzzy models. In other words, the imperfect premise matching technique provides a more general approach in designing fuzzy controllers. The advantage of the proposed fuzzy controller design method is that it can be enhanced more flexibility and robustness than well-known parallel distributed compensation based fuzzy control approach. At last, two numerical examples are given to illustrate the usefulness and effectiveness of proposed fuzzy controller design method.
    No preview · Article · Apr 2015 · Neurocomputing
  • Wen-Jer Chang · Yao-Chung Chang · Cheung-Chieh Ku
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    ABSTRACT: The passive fuzzy control problem is studied in this paper via line-integral fuzzy Lyapunov function for nonlinear ship drum-boiler systems with multiplicative noises. The Takagi-Sugeno (T-S) fuzzy model is employed to represent the nonlinearities of the multiplicative noised nonlinear ship drum-boiler systems. For stability analysis and synthesis, the sufficient conditions are derived via line-integral fuzzy Lyapunov functions. These conditions are transformed into the linear matrix inequality (LMI) forms which can be solved by the convex optimal programming algorithm. In addition, the passivity theory is employed to deal with the effect of external disturbance in the ship drum-boiler system. Finally, a numerical example is provided to show the applicability and effectiveness of the proposed fuzzy controller design approach.
    No preview · Article · Apr 2015 · Journal of Dynamic Systems Measurement and Control
  • Wen-Jer Chang · Ying-Jie Shih
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    ABSTRACT: In this paper, a H∞ performance constrained fuzzy control approach is investigated for a class of nonlinear stochastic systems subject to actuator saturation. The nonlinear stochastic systems considered in this paper are represented by Takagi-Sugeno fuzzy models with multiplicative noises. According to H∞ performance constraint and actuator saturation, it is shown that the stabilization of multiplicative noised Takagi-Sugeno fuzzy models can be formulated as a convex optimization problem subject to linear matrix inequalities. The proposed fuzzy control method is accomplished based on the Lyapunov stability theory. Simulation study on a continuous-time nonlinear stochastic ship steering system is given to show the performances of the proposed H∞ performance constrained fuzzy control methodology.
    No preview · Article · Jan 2015 · Neurocomputing
  • Wen-Jer Chang · Bo-Jyun Huang
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    ABSTRACT: The multi-constrained robust fuzzy control problem is investigated in this paper for perturbed continuous-time nonlinear stochastic systems. The nonlinear system considered in this paper is represented by a Takagi–Sugeno fuzzy model with perturbations and state multiplicative noises. The multiple performance constraints considered in this paper include stability, passivity and individual state variance constraints. The Lyapunov stability theory is employed to derive sufficient conditions to achieve the above performance constraints. By solving these sufficient conditions, the contribution of this paper is to develop a parallel distributed compensation based robust fuzzy control approach to satisfy multiple performance constraints for perturbed nonlinear systems with multiplicative noises. At last, a numerical example for the control of perturbed inverted pendulum system is provided to illustrate the applicability and effectiveness of the proposed multi-constrained robust fuzzy control method.
    No preview · Article · Sep 2014 · ISA Transactions
  • Wen-Jer Chang · Bo-Jyun Huang
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    ABSTRACT: In this paper, a fuzzy controller design problem for continuous perturbed nonlinear stochastic systems with state multiplicative noises is investigated. In order to simultaneously achieve variance and passivity constrained performances, some sufficient conditions are derived based on the Lyapunov theory. These sufficient conditions are in term of the linear matrix inequality forms that can be solved by the convex optimal programming algorithm. Besides, the parallel distributed compensation concept is employed to construct the fuzzy controllers. Finally, a numerical simulation example is given to show the effectiveness and applicability of the proposed fuzzy control methodology.
    No preview · Conference Paper · Jul 2014
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    Wen-Jer Chang · Bo-Jyun Huang · Po-Hsun Chen
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    ABSTRACT: For nonlinear discrete-time stochastic systems, a fuzzy controller design methodology is developed in this paper subject to state variance constraint and passivity constraint. According to fuzzy model based control technique, the nonlinear discrete-time stochastic systems considered in this paper are represented by the discrete-time Takagi-Sugeno fuzzy models with multiplicative noise. Employing Lyapunov stability theory, upper bound covariance control theory, and passivity theory, some sufficient conditions are derived to find parallel distributed compensation based fuzzy controllers. In order to solve these sufficient conditions, an iterative linear matrix inequality algorithm is applied based on the linear matrix inequality technique. Finally, the fuzzy stabilization problem for nonlinear discrete ship steering stochastic systems is investigated in the numerical example to illustrate the feasibility and validity of proposed fuzzy controller design method.
    Preview · Article · Jan 2014 · Mathematical Problems in Engineering
  • Wen-Jer Chang · Cheung-Chieh Ku · Zong-Guo Fu
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    ABSTRACT: The passive fuzzy control for discrete-time uncertain Takagi-Sugeno (T-S) fuzzy models with multiplicative noises and time delay is investigated subject to robust asymptotical stability. Applying Jensen's inequality and free-weighting matrix technique, less conservative sufficient conditions are derived via choosing Lyapunov function to analyze and synthesize the robust asymptotical stability and passivity of closed-loop system. The derived conditions are not strictly linear matrix inequality (LMI) problems, thus the cone complementarity technique is employed to propose a suboptimal technique to solve the proposed nonstrictly LMI problems. An algorithm is developed in this paper to design the fuzzy controller which can be accomplished by state-feedback scheme or output-feedback scheme. Finally, numerical examples are provided to demonstrate the feasibility and applicability of the proposed fuzzy controller design technique.
    No preview · Article · Dec 2013 · Mathematical Problems in Engineering
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    Wen-Jer Chang · Cheung-Chieh Ku · Hao-Jie Liang
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    ABSTRACT: This paper deals with the fuzzy controller design problem for discrete-time Takagi-Sugeno (T-S) fuzzy systems with multiplicative noises. Using the Lyapunov stability theory and Itô formula, the sufficient conditions are derived to guarantee the stability of the closed-loop nonlinear stochastic systems subject to actuator saturation. Based on the Parallel Distributed Compensation (PDC) concept, the fuzzy controller can be obtained to stabilize the T-S fuzzy models with multiplicative noises by combining the same membership functions of plants and desired state feedback gains. In order to illustrate the availability and practicability of proposed fuzzy controller design approach, the numerical simulations for the nonlinear truck-trailer system are given to demonstrate the applications of this paper.
    Preview · Article · Dec 2013 · Mathematical Problems in Engineering
  • Wen-Jer Chang · Fung-Lin Hsu · Bo-Jyun Huang
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    ABSTRACT: This paper proposes a passive fuzzy controller design methodology for stabilization of nonlinear system with external disturbance based on multiplicative noised Takagi-Sugeno fuzzy model and parallel distributed compensation control design. Applying the Itô's formula and the sense of mean square, the sufficient conditions are developed to analyze the stability and to design the controller for stochastic nonlinear systems. The sufficient conditions derived in this paper belong to the linear matrix inequality forms which can be solved efficiently by convex optimal programming algorithm. Besides, the passivity theory is applied to discuss the effect of external disturbance on system. Finally, a ball and beam system is provided in the example to demonstrate the applications of the proposed fuzzy controller design technique.
    No preview · Conference Paper · Dec 2013
  • Wen-Jer Chang · Bo-Jyun Huang · Zong-Guo Fu
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    ABSTRACT: An individual state variance constrained fuzzy controller design methodology is developed in this paper to achieve state variance constraint and passivity constraint for discrete nonlinear multiplicative noised stochastic systems. The discrete nonlinear multiplicative noised stochastic system considered in this paper is represented by the discrete-time Takagi-Sugeno fuzzy model. The proposed fuzzy controller is constructed by the concept of parallel distributed compensation. The sufficient conditions are derived based on the Lyapunov theory. Employing the matrix transformation technique, these sufficient conditions can be expressed in terms of linear matrix inequalities. Finally, the feasibility and validity of the proposed method are illustrated with a numerical simulation example.
    No preview · Conference Paper · Dec 2013
  • Wen-Jer Chang · Bo-Jyun Huang · Po-Hsun Chen
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    ABSTRACT: This paper studies the passive and individual variance constrained fuzzy control problem for discrete-time stochastic Takagi-Sugeno fuzzy systems. The performances considered in this paper include passivity constraint and individual state variance constraint. The proposed fuzzy control is accomplished by using the concept of parallel distributed compensation. Based on the Lyapunov stability theory, the sufficient conditions are derived to achieve the above multiple performance constraints. In order to illustrate the applicability and validity of the proposed fuzzy control method, a numerical control simulation for a discrete-time Takagi-Sugeno fuzzy system with multiplicative noise is provided.
    No preview · Conference Paper · Dec 2013
  • Wen-Jer Chang · Sin-Sian Jheng · Cheung-Chieh Ku
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    ABSTRACT: This article presents an estimated state feedback fuzzy controller design method for uncertain passive discrete-time nonlinear stochastic systems with multiplicative noises. The nonlinear stochastic systems considered in this article are represented by Takagi–Sugeno (T–S) fuzzy models. For describing stochastic behaviors, stochastic differential equations are used to structure the stochastic T–S fuzzy model for representing nonlinear stochastic systems. Besides, the uncertainties of the controlled system are considered for dealing with molding errors and varying parameters. The concept of parallel distributed compensation is employed in this article to construct the estimated state feedback fuzzy controllers. Applying the Lyapunov and passivity theories, the sufficient stability conditions are derived in terms of linear matrix inequality. Finally, a numerical example is provided to show the effectiveness and applicability of the proposed fuzzy controller design approach.
    No preview · Article · Sep 2013 · Journal- Chinese Institute of Engineers
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    ABSTRACT: This paper investigates a fuzzy controller design method for discrete-time nonlinear stochastic time-delay systems which are presented by the Takagi-Sugeno (T-S) fuzzy model with multiplicative noises. Utilizing the proposed design method, the fuzzy controller can be carried out via not only state feedback scheme but also output feedback scheme. Both of them are accomplished by the concept of imperfect premise matching (IPM). For discussing the stabilization problem, the Lyapunov-Krasovskii function and passivity theory are applied to derive the sufficient conditions. Moreover, the discrete Jensen inequality is employed to decrease the conservatism of the proposed method. Finally, a numerical example for the control of a nonlinear time-delay pendulum system is provided to show the effectiveness and usefulness of the proposed design method.
    No preview · Article · Jun 2013 · International Journal of Control Automation and Systems
  • Wen-Jer Chang · Bo-Jyun Huang
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    ABSTRACT: The variance and passivity constrained fuzzy control problem for the nonlinear ship steering systems with state multiplicative noises is investigated. The continuous-time Takagi-Sugeno fuzzy model is used to represent the nonlinear ship steering systems with state multiplicative noises. In order to simultaneously achieve variance, passivity, and stability performances, some sufficient conditions are derived based on the Lyapunov theory. Employing the matrix transformation technique, these sufficient conditions can be expressed in terms of linear matrix inequalities. By solving the corresponding linear matrix inequality conditions, a parallel distributed compensation based fuzzy controller can be obtained to guarantee the stability of the closed-loop nonlinear ship steering systems subject to variance and passivity performance constraints. Finally, a numerical simulation example is provided to illustrate the usefulness and applicability of the proposed multiple performance constrained fuzzy control method.
    No preview · Article · Mar 2013 · Mathematical Problems in Engineering
  • Wen-Jer Chang · Yao-Chung Chang
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    ABSTRACT: This paper studies the line-integral fuzzy Lyapunov function based fuzzy controller design for continuous-time Takagi-Sugeno fuzzy systems with multiplicative noises. For stability analysis and synthesis, the sufficient conditions are derived via line-integral fuzzy Lyapunov functions. These conditions belong to the linear matrix inequality forms which can be solved by the convex optimal programming algorithm. In addition, the passivity theory is utilized to deal with the effect of external disturbance in the system. Finally, a numerical example is supplied to show the usefulness and effectiveness of the proposed design method.
    No preview · Conference Paper · Jan 2013
  • Wen-Jer Chang · Bo-Jyun Huang
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    ABSTRACT: A passive fuzzy controller design methodology is developed in this paper to achieve state variance constraint for continuous-time Takagi-Sugeno (T-S) fuzzy models. The proposed fuzzy controller is constructed by the concept of Parallel Distributed Compensation (PDC). Based on the Lyapunov theory, the sufficient conditions are derived to guarantee the stability of the closed-loop system. Besides, the passivity and variance constraints are also considered in the derivations of these sufficient conditions. These sufficient conditions belong to the Linear Matrix Inequality (LMI) forms, which can be solved by the convex optimal programming algorithm. Finally, the feasibility and validity of the proposed method are illustrated with a numerical simulation example.
    No preview · Conference Paper · Jan 2013
  • Wen-Jer Chang · Cheung-Chieh Ku · Chia-Hao Chang
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    ABSTRACT: This paper presents a relaxed scheme of fuzzy controller design for continuous-time nonlinear stochastic systems that are constructed by the Takagi–Sugeno (T–S) fuzzy models with multiplicative noises. Through Nonquadratic Lyapunov Functions (NQLF) and Non-Parallel Distributed Compensation (Non-PDC) control law, the less conservative Linear Matrix Inequality (LMI) stabilization conditions on solving fuzzy controllers are derived. Furthermore, in order to study the effects of stochastic behaviors on dynamic systems in real environments, the multiplicative noise term is introduced in the consequent part of fuzzy systems. For decreasing the conservatism of the conventional PDC-based fuzzy control, the NQLF stability synthesis approach is developed in this paper to obtain relaxed stability conditions for T–S fuzzy models with multiplicative noises. Finally, some simulation examples are provided to demonstrate the validity and applicability of the proposed fuzzy controller design approach.
    No preview · Article · Oct 2012 · Journal of the Franklin Institute
  • Wen-Jer Chang · Che-Pin Kuo · Bo-Jyun Huang
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    ABSTRACT: This paper deals with the control problem of nonlinear stochastic ship steering system. The system exhibits nonlinear interaction on three degrees of freedom (surge, sway and yaw) by means of main propellers aft of the ship. For guaranteeing the global stability, the Takagi-Sugeno (T-S) fuzzy model is employed to represent nonlinear ship steering system. Using the technique of Imperfect Premise Matching (IPM), the fuzzy controller is designed without limitation of sharing the same membership function of the fuzzy model. In other words, the IPM technique provides a generalization in designing the fuzzy controller. Besides, the fuzzy controller design can be enhanced more flexibility and robustness than one applies Parallel Distributed Compensation (PDC) approach. Based on the Lyapunov theory, the stability conditions are derived into Linear Matrix Inequality (LMI) problems for applying the convex optimal algorithm. At last, simulation results are given to show the effectiveness of the proposed design method.
    No preview · Article · Dec 2011