Adaptive Fuzzy Control Of Nonlinear Systems With Unknown Virtual Control Gains

This thesis mainly studies the output feedback control problem of a kind of nonlinear strict feedback system with unknown virtual control gain.For this kind of problem in this research,we put forward a kind of single input and single output strict feedback system design method of robust observer,and further put forward a kind of adaptive fuzzy output feedback control scheme based on observer.A robust observer is built using convex combination,and an ideal controller is constructed using the fuzzy adaptive control method and Backstepping technique.At the same time,using Lyapunov stability theory,the stability of closed-loop system is proved,and all the signals of the closed-loop system are half global and finally bounded.The main research contents are as follows:First,for a single input and single output system with unknown virtual gain,the robust observer is first designed,and the adaptive fuzzy control principle is proposed by Backstepping technology to design the adaptive fuzzy controller.The stability of the closed-loop system is proved by using Lyapunov stability theory.Second,for the problem of the study in the last chapter.To study the situation with the input have the dead zone.The solution to the problem is to regard the input dead zone as the sum of a linear dead zone and a bounded non-linear dead zone,This gives the design method of the observer and the controller.Third,the third chapter studies the content of tracing control,it was proved that the output feedback control strategy is proposed to guarantee that all the signals of the closed-loop system is globally uniformly ultimately bounded,and the tracking error converge to a small neighborhood of the origin.Finally,the adaptive fuzzy control system with unknown virtual control gain is summarized and the existing research content is prospected.