The Study On Control Method For Nonlinear Systems Based On Element Models

In modern control theory ,The study of linear control has been very comprehensive while that of nonlinear control systems remains a difficult problem. There is yet no complete and systematic on the research of nonlinear systems theory due to the complexity of nonlinear systems, and most of the contemporary methods in this area have problems such as uncertainty, no hierarchy, and limitations on the range of applications. As a result, no comprehensive and effective theory has been proposed on the research of nonlinear control system. This paper is based on the analysis of nonlinear systems dynamics. By building a mode of approaching element, analyzing of the movement features of nonlinear systems in approaching element space, the design of optimal control of nonlinear systems is completed.Firstly, a mode of approaching element is defined, and some methods then are proposed to build the approaching element model to approximate nonlinear systems. Based on the element model of approaching, a state transfer matrix is set up for nonlinear controlled systems. The analysis on controllability of nonlinear systems can be carried out with the state transfer matrix, to find the optimal control strategy,and complete the design of optimal control of nonlinear systems. An integration of the quantity space, approximation space and symbol space has been made through the element model of approaching, so as to conduct an effective and complete analysis and research on the nonlinear systems.