Research On Control Methods Of Nonlinear Systems With Polynomial Nonlinear Terms

As is well known,output feedback control problem of nonlinear systems has been widely paid attention to,compared with linear systems,nonlinear systems are more accu-rate and more able to show the essential characteristics of the systems.Hence,nonlinear system control design has always been a hot spot and the difficulty in the field of control theory,many models in the spring,nonlinear resistance circuit and so on display poly-nomial nonlinearities.Therefore,output feedback controller design of nonlinear systems with polynomial nonlinearities has both theoretical significance and practical value.This paper considers the design and analysis of output feedback controller for nonlinear sys-tems with polynomial nonlinearities.The main contents of this paper are mainly divided into the following three parts:The first part investigates the output feedback stabilization problem for a class of high-order nonlinear systems with polynomial nonlinearities.The innovations are that the studied systems include more general high-order and low-order nonlinearities,moreover,the nonlinearities depend on output polynomial.Based on the homogeneous domination and adding a power integrator methods,by constructing the novel Lyapunov function and observer,an output feedback controller is developed to guarantee that the equilibrium of the closed-loop system is globally uniformly asymptotically stable.The second part studies the problem of output feedback disturbance attenuation for a class of nonlinear systems with input matching uncertainty.The novelties are that the systems to be investigated contain disturbance and input matching uncertainty,whose nonlinearities simultaneously possess unknown input and output polynomial functions growth rates.Combining the technique of dynamic gain and extended state observer,an adaptive output feedback controller is designed to guarantee that the states of the closed-loop system are globally bounded,and the disturbance attenuation is achieved in the L₂-gain sense?The third part gives the summary and outlook of the thesis.