Analysis And Synthesis For Several Classes Of Switched Fuzzy Systems

A switched fuzzy system is a switched system whose subsystems are all fuzzy sys-tems. Exhibiting features of both switched systems and fuzzy systems, switched fuzzy systems are more complicated hybrid systems. In practice, switched nonlinear systems can be more precisely described by switched fuzzy systems, so the research of switched fuzzy systems has received a great amount of attention. However, only a few results on such issues have been reported up to now. This dissertation studies the problem of stabi-lization, feedback passification, H? control for several classes of switched fuzzy systems. The main contributions are as follows.(1) The non-fragile guaranteed cost control problem for a class of uncertain switched fuzzy systems is investigated. Based on the single Lyapunov function method and the generalized multiple Lyapunov functions method, non-fragile guaranteed cost controllers and a switching law are designed to guarantee that the closed-loop switched fuzzy system is asymptotically stable and the non-fragile guaranteed cost function possesses an upper bound.(2) The robust stabilization problem is studied for a class of switched fuzzy systems with saturating actuators, whose fuzzy subsystems are not assumed to be asymptotically stabilizable. Based on the multiple Lyapunov functions method, a switching law and state feedback controllers are designed such that the switched fuzzy system with saturating actuators is asymptotically stable in the domain of attraction. In addition, the estimation of the domain of attraction is presented by solving an optimization problem.(3) The problem of feedback passification for switched fuzzy systems is investigated where each fuzzy subsystem is non-feedback passive. A switching law and controllers are designed to guarantee that the closed-loop switched fuzzy system is passive by using multiple Lyapunov functions method. According to the situation that the system state is available or not, conditions for feedback passification are derived for the switched fuzzy system with time delays and for the switched fuzzy system based on the observer, respec-tively.(4) The robust H? control problem for a class of networked switched fuzzy systems is studied. First of all, such systems with network induced delays and packet dropout are represented as switched fuzzy systems with time-varying delays. The solvability of the H? control problem for each fuzzy subsystem is not assumed. Based on the multiple Lyapunov functions method, a sufficient condition for solvability of the H? control prob-lem is derived for the networked switched fuzzy system. Meanwhile, a switching law and controllers are designed.(5) The two-layer multiple Lyapunov functions method is presented for the first time and the stabilization problem for a class of switched fuzzy systems is investigated. Two-layer Lyapunov functions are multiple either for the fuzzy subsystems or for the lo-cal linear models, which substantially decreases the conservativeness of the issue. We give a sufficient condition for stabilization of the switched fuzzy system and a design for a switching law and controllers by using the two-layer multiple Lyapunov functions method.The conclusions and perspectives are presented in the end of the dissertation.