Output Feedback Control Of Switched Systems

Switched system is one of the most important branches of hybrid systems, and is essentially a nonlinear system. It consists of several linear subsystems and switching law which decides the active subsystem at each instant time. Currently, many kinds of the index performance for system synthesize problem that can be carried out only depending on state feedback. It is shown that state feedback is better than output feedback on function. However, the state is a system inner variant set, or because of all states cannot be measured directly, or because of the measurement means' restriction in the economy and the applicability, make the physical realization of the state feedback become impossibly or very difficult, which leads to design of thedynamic output feedback controllers. Robust H_∞dynamical output feedback controlfor uncertain switched systems and based-observer robust H_∞output feedback controlfor switched systems with time-delay are discussed in this dissertation. All summarize as follows:First, the problem of robust H_∞dynamical output feedback design for switchedsystems with time-varying and unknown but norm-bounded uncertainties in states as well as inputs is investigated. Based on the completeness condition and the Lyapunovfunction approach, a sufficient condition for the existence of robust H_∞dynamical output feedback controllers for switched systems is obtained. At the same time, H_∞dynamical output feedback controllers of subsystems and switching strategy aredesigned. By using the variable substitute method, the nonlinear matrix inequalities are changed into linear matrix inequalities (LMIs) which are easily solved. The simulation shows the validity of the proposed design approach.Second, Observer-based robust H_∞output feedback control for switched systems with time-delay in state is investigated. By combining multiple Lyapunov functions with linear matrix inequalities technique, the observer-based robust H_∞output feedback controllers are designed for switched systems with time-delay. The sufficient conditions of observer-based robust H_∞output feedback control forswitched systems with time- delay independent is obtained. Furthermore, the sufficient condition was turned into a feasibility problem with a set of LMIs. At the same time, the parameterized characterizations of the switching observer and controller and the corresponding switching strategy based on restructured state are provided. The simulation shows the validity of the proposed design approach.The summary is in the last. The problems and directions for future study are pointed out.