Fuzzy Control For T-S Fuzzy Time-delay Systems With Actuator Saturating

In recent years,there has been a popular study in the comprehensive control issue of nonlinear systems and time-delay systems subject to actuator saturation,which has attracted a vast amount of research attention.In many practical control systems,in different extent,there is a delay phenomenon. Such as networked control systems(NCSs),transmission systems,chemical process systems are typically time-delay systems.The inherent time delay of a controlled plant has brought a lot of difficulties to system analysis and controller design,time-delay systems are considered as the most difficult to controlled plant.At the same time,taking into account the physical properties and the actual significance of system components,the occurrence of the actuator saturation is relatively common phenomenon.Usually, actuator saturation can severely degrade system performance and sometimes even make a stable system unstable.Therefore,stability analysis and the design of the controller of nonlinear time-delay systems with actuator saturation have important theoretical and practical significance.Especially, in the modern society that the digital communications technology is rapidly developing,the stabilization problem for nonlinear NCSs subject to actuator saturation is also a significant issue.The main results in the dissertation are as follows:(1) The significance of this paper is introduced,not only in theory but also in applications,and the related development both abroad and at home is recalled briefly.(2) For the nonlinear system represented by Takagi - Sugeno(T-S) fuzzy model,stability analysis and fuzzy controller design method are investigated for a class of nonlinear systems with actuator saturation and time-varying delay.By using parallel distributed compensation(PDC) technique,quadratic Lyapunov function,Razumikhin stability theorem and linear matrix inequalities(LMI) approach,a delay-dependent criterion of local asymptotic stability for the closed-loop fuzzy systems is established, and the design method of the fuzzy controller is presented.Meanwhile,for the case that the actuator is non-standard saturation,some corresponding results are proposed.The estimation of the domain of attraction for closed-loop fuzzy systems is obtained by solving such LMIs.Then,a design procedure for the fuzzy controller that maximizes the estimation of the domain of attraction is addressed.A numerical example is given to illustrate the effectiveness of the proposed method.(3) The stabilization problem for a class of nonlinear NCSs with actuator saturating is studied.First,by using PDC technique,a T-S fuzzy time-delay model is established to represent the systems under consideration of both network-induced delay and packet dropouts in transmission.Then,by means of Lyapunov-Krasovskii functional method,the input-delay approach and free weighting matrix techniques,a delay-dependent criterion of asymptotic stability for the nonlinear NCSs with actuator saturating is established in terms of LMI,and the design method of the corresponding controller is presented.The problem of estimating the domain of attraction for such systems is obtained by solving such LMIs.A numerical example is given to illustrate the effectiveness of the proposed method.(4) The main results of the thesis are concluded,and some research issues in future are proposed.