Output-Feedback Stabilization Control Design For A Class Of Nonlinear Uncertain Systems

In this paper, the problem of output-feedback control is investigated for a class of nonlinear systems with uncertainties. Based on the multivariable analog of circle criterion, an observer is introduced for the state estimates and the dynamics of the estimation error are thus derived. Then, the output-feedback stable controller, the adaptive output-feedback stable controller and asymptotical tracking controller are constructively designed using integral backstepping approach. It is shown that, the controllers designed keep the equilibrium at origin, and ensure the closed systems derived the desired performance. Concretely speaking, the feature of this paper are as follows:1) The nonlinear systems to be considered in this paper possess two types of nonlinear dynamic characterizations, thus they are more general than the results that related to this paper. Firstly, under the condition that the known nonlinearities satisfy the multivariable nonlinear monotony increasing condition, and the unknown nonlinearities can be dominated by a known function, the stable controller is constructively designed for such class of nonlinear systems; secondly, when the known nonlinearities satisfy the same condition, the unknown nonlinearities can be dominated by a known function multiplying an unknown constant, the adaptive stable controller is constructively designed for such class of nonlinear systems; at last, when the known nonlinearities satisfy the same condition, the unknown nonlinearities are zero, we design the tracking controller for the system. The controllers designed not only ensure that the closed systems derive the desired performance, but also ensure that the observer systems are asymptotically convergent.2) In this paper, when we design output-feedback controllers for the systems, the technique of completing square is used sufficiently, the over parameters are avoided effectively. The controllers designed make the systems derive desired performance. The ultimate simulation results are presented to show the effectiveness of the each result of this paper respectively.This paper consists of 5 chapters. In chapter 1, we introduce the devel-...