Output Feedback Control Of Uncertain Nonlinear Cascade Systems

Uncertain nonlinear system control is an important topic in control theory. In all, we have got a lot of results in the area of state-feedback adaptive control for a class of uncertain nonlinear systems. But comparatively speaking, we have got fewer in the area of output-feedback adaptive control for a class of uncertain nonlinear systems, moreover, there are still many problems to be solved. Specially, the problem of output-feedback adaptive control for a class of uncertain nonlinear cascade systems with unknown control directions and output-feedback adaptive control for a class of uncertain time-delay nonlinear cascade systems with unknown control directions about which we need to discuss and research further. In this paper, we will talk about these two kinds of nonlinear systems.My thesis is organized as follows:Chapter 1; Introduce the background of this topic, internal and overseas research situations, theoretical and Practical significance, the main contributions of this paper.Chapter 2:Introduce the basic theory involved in my thesis, including some basic concepts, related theory and some lemmas. Specifically we mainly introduce the definition of Lyapunov function, the application of back-stepping design in nonlinear systems, Nussbaum function, Barbalat lemma and some related lemmas. We make our focus on the introduction of the application of back-stepping design in nonlinear system.Chapter 3:Introduce the output-feedback adaptive control for a class of uncertain nonlinear cascade systems with unknown control directions. Because of the unknown control directions, we pull in the concept of Nussbaum function which has an advantage in solving this control problem for this kind of system.Chapter 4:We extend the contents of Chapter 3 to time-delay systems. Introduce the output-feedback adaptive control for a class of uncertain time-delay nonlinear cascade systems with unknown control directions. The design thought way is the same as that of Chapter 3, and there is nothing distinction but the choose of Lyapunov function.Chapter 5, Summarize this papers and propose the problem for further research.