Analysis And Control Design Of Interval Type-2 T-S Model Based Networked Systems

Fuzzy control is a universal and powerful tool to deal with complicated nonlinear systems,and has been successfully applied to the industrial processes.The T-S fuzzy model can approximate complex nonlinear systems with linear subsystems in the form of weighted sums.In recent years,nonlinear system control based T-S model has been widely used in practical production.T-S fuzzy state feedback controller is assumed that fuzzy weights do not contain uncertainty information.However,in practice,nonlinear systems in many cases have uncertainties.The fuzzy weights of T-S fuzzy models may contain uncertain information.Compared with the type-1 fuzzy sets,the type-2 fuzzy sets overcome the defects of the type-1 fuzzy sets,and type-2 fuzzy sets have better abilities to deal with uncertainty.Interval type-2 is a special form of type-2 fuzzy set,whose calculation is relatively simple.Therefore,interval type-2 fuzzy model is adopted to deal with uncertainty of control systems.This dissertation studies the stabilization of T-S model based interval type-2 fuzzy systems,and includes the following several aspects:In the first part,the problem of state feedback control for a class of interval type-2 networked systems is discussed.For the network delay in interval type-2 networked systems,a sufficient condition for the asymptotic stability of the considered system is established by constructing Lyapunov-Krasovskii functional and using inequality scaling and matrix decomposition techniques.A state feedback controller is designed which makes the closed-loop system asymptotically stable.Finally,a numerical simulation is given to verify the effectiveness of the design method.The second part focuses on studying the H_? control of a class of interval type-2networked systems with external disturbances.The sufficient condition of asymptotic stability for the system is established using the properties of the upper and lower membership functions of the interval type-2.The matrix decomposition technique is used to obtain the sufficient conditions for the stability of interval type-2 networked systems with the given H_? performance.A state feedback controller for the closed-loop system is proposed satisfying the given H_? performance.The numerical simulation verifies the feasibility of the design method.In the third part,the controller design of interval type-2 delayed systems is considered.By using Lyapunov-Krasovskii functional and combining with the related inequality scaling techniques,the asymptotic stability condition of uncertain nonlinear systems with time-varying delays is obtained and the controller design method is given.Based on the stability conditions and using the properties of the type-2 fuzzy basis,a less conservative condition of stability is established.Finally,a numerical simulation verifies the effectiveness of the design method.