Global Output Feedback Control For Two Types Of Nonlinear Systems

First of all, a scaling gain is introduced into the high-order system in the study under a group of coordinate transformation and the adding a power integrator technique, Moreover, we explicitly construct a nonlinear stabilizer with adjustable coefficients. Then, Under the aid of the homogeneous domination approach and Lyapunov-Krasovskii functional, This paper is concerned with the problem of global output feedback control for a class of nonliear systems whose output functions are not precisely known and the problem of global output feedback stabilization for a class of lower-triangular nonlinear systems with time-varying input delay. Global output feedback control has been widely used in the fields of medical science, physics, water conservancy project, information technology, industrial manufacturing and so on. The problem of global output feedback stabilization for nonlinear systems is one of the most important and challenging problems in the field of nonlinear control. But most of the existing output feedback stabilization results all require precise knowledge of the nonlinear functions and output functions, which are necessary to construct the nonlinear observers. When the nonlinear terms and output functions are not precisely known, the observers proposed in the aforementioned works will be no longer feasible.To deal with the unknown nonlinears and unknown output functions, an explicit dynamic feedback law that solves the problem of global stabilization is designed. The feasibility of the feedback controller are proved.The main contents of this paper are as follows: In Chapter1, several main global control approaches and the latest research develop-ment of problems studied in this paper are simply presented, and a brief introduction is given to related research method and our work.In Chapter2, this part employs homogeneous domination approach to solve the prob-lem of global output feedback control for a class of nonliear systems whose output functions are not precisely known. A state compensator will be constructed without using z1, and acorresponding controller will be constructed to globally stabilizethe nominal system. Then we further employ the homogeneous domination approach in which a tunable scaling gain will be introduced to the compensator and controller. In this paper, we first show that the scaled output feedback controller can be used to solve the problem of global output feedback stabilization for a class of upper-triangular systems. Moreover, we show that the scaled output feedback clntroller can also can be used to solve the problem of global practical tracking for a class of nonlinear systems.In Chapter3, this paper consider the problem of global output feedback tracking for a class of lower-triangular nonlinear systems with time-varying input delay. First of all, a scaling gain is introduced into the high-order system in the study under a group of coor-dinate transformations to deal with the nonlinear terms as well as the input delay. Based on the homogeneous domination approach, the closed-loop system is global asymptotically stable by choosing an appropriate Lyapunov-Krasovskii functional.