Output-feedback Stabilization For Nonlinear Systems

Using extending the adding a power integrator technique, this paper designs a one-dimensional nonsmooth compensator and gain function, it also constructs a smooth robust adaptive controller, and then by using lyapunov stability theory, considering the problems of the global output stabilization for a class of nonlinear systems and robust adaptive control. Global output stabilization is widely applied in various engineering disciplines, and extended to biology, medicine, environment, economic management and many other social life. In view of the problem of stabilization for two-order uncertain nonlinear systems and adaptive control for high-order nonlinear uncertain systems, this paper designs smooth time-varying adaptive dynamic feedback controller, to ensure global stabilization of the nonlinear system, but also it proves the feasibility of the controller.First, the problem of the global stability for a class of fourth-order nonlinear systems is studied in the first chapter, which are transformed to equivalent system by making a change, using the analog method constructed Lyapunov functional of the fourth-order nonlinear systems. A sufficient condition is obtained to ensure the global stability for the class of zero solution of fourth-order nonlinear system.Then, the second chapter deals with the problem of the global finite-time stabilization by output feedback for a class of second-order uncertain nonlinear systems. By the choice of observer and using extending the adding a power integrator technique, A feedback controller is designed to ensure the global finite-time stabilization of the closed-loop system.Finally, the problem of the robust adaptive control for a class of high-order nonlinear uncertain systems is considered in the third chapter. By modifying the adding a power integrator technique, a smooth robust adaptive controller is explicitly constructed to render the global stabilization of nonlinear system.