Research Of The Optimal Control For Nonlinear Time-delay Systems

There are a lot of nonlinear characteristics in actual controlled object or processing. Because of nonlinear characteristics, the process of industry will not become stable. The control systems will lack robustness. It will affect process of industry. Therefore, the analysis of problem for nonlinear systems is a significant research both in theory and in practice. The paper presents the related problems of nonlinear systems and current research. The advanced ways of control design for nonlinear systems are described at home and aboard in detail. By using a successive approximation approach, the two point boundary value problem of optimal control of nonlinear system can be solved.Following, the article discusses the optimal output tracking control for a special class of nonlinear time delay system that is bilinear time delay system. According to a necessary condition for the maximum principle, the nonlinear time delay system change into the two point boundary value problem. Then, the new two point boundary value problem is transformed into two decoupled linear differential equations'sequences by using the successive approximation approach. By solving the equation sequences and intercepting the limit term of sequence, the suboptimal control law could be got. The optimal output tracking control law can be obtained vector sequence which converges at the law of original system by solving the equation sequences.Then, optimal control problems of a kind of time delay systems are studied in a deep-going way. At the same time, for the systems with persistent external disturbances whose dynamics are described by an exosystem, a disturbance rejection method is presented. The existence and uniqueness of the control law are studied and an approximate design procedure of the law is given. The physical realization problem is resolved.Finally, the optimal control problem of the status delay system with time delay in control action is resolved by the method that is made mention of this paper. The system is transformed into status delay system without time delay in control action by transformation of state transition matrix. In accordance with a successive approximation approach, the optimal control law of system is obtained.A lot of simulation result show that this approach possesses efficiency. The applied scope of method is expanded. The main work in this dissertation is summarized and a proposition is indicated on the research work in the future.