Observer-based Adaptive Fuzzy Control For A Class Of Nonlinear Strict Feedback Systems

The nonlinear and time-delay phenomena in industrial engineering are ubiquitous,and the non-linearity,uncertainty and delay of the system will affect the performance of the system and bring some difficulties to the control design of the system.In recent years,with the advancement of modern technology,nonlinear system and time-delay system analysis and control design has become a hot spot for experts and scholars.The control design method combined with the approximation theory of fuzzy logic system and adaptive backstepping technology is of great concern.Strict feedback system is a special form of pure feedback system,but its control design and performance analysis has a wide range of application background.In this paper,we study the control design problem of single-input single-output nonlinear strict feedback system and its time-delay system.The main contents are as follows:Firstly,a class of single-input single-output nonlinear strict feedback system is studied.The adaptive fuzzy backstepping method is used to construct the system controller.Since this system state is not directly measurable,the state observer is designed to estimate the state variables of the system.In order to reduce the estimation error of the system state variables,a fuzzy logic system is set up in the observer to increase the accuracy of the state estimation.The convexity and matrix inequality are used to solve the observation gain matrix,which solves the problem of inconsistency between the existing observer design and the dynamic stability of observation error.Secondly,an adaptive fuzzy control problem for a class of nonlinear strictly feedback systems with time delay is studied.The above-mentioned observer-based fuzzy adaptive output feedback control design method is further extended to the nonlinear strictly feedback time-delay system,and the corresponding fuzzy adaptive output feedback stabilization control scheme is given.Thirdly,the simulation of the above two kinds of nonlinear systems is carried out.