Research On Optimum Control For A Kind Of Time-Delay System

In the industrial process, there are a lot of plants which possess the characteristic of time-delay, especially in the petroleum, chemical, brewing, pharmaceutical, metallurgy and other industries. Because of the existence of long time-delay, common control method is difficult to guarantee the good control quality, and the precision and stability of control system is badly affected. Therefore, the control of large time-delay plant is a big problem in the field of automation all the time. Also, it is considered as a kind of plant which is hard to be controlled, the longer the time-delay takes, the harder the plant is to be controlled. Due to this kind of plant widely exists in industrial process and is difficult to be controlled, the research on this issue is of significance in practice. This paper does some research on the optimum control for this kind of time-delay system. Firstly, the design of optimal system is based on the functional indicators and the optimal system transfer function. So, through a comparative analysis of different functional indicators, ultimately we choose ITAE function as a system’s performance indicators and use the improved particle swarm optimization to calculate optimal control law of common system. Secondly, the theory of twice optimum has been applied to design of control system for time-delay plant and this method is simple and flexible operation. However, this method is imperfect, so the theory is introduced in details and design method is given in the paper. At the same time, this paper does the research on improved method, and results show that the method has significantly improved the dynamic property, the steady accuracy, and the robustness of this kind of control system. Finally, for the situation that twice optimum control can not be achieved, fuzzy control is proposed. The ITAE optimal control law is applied to optimize the quantifying factors and scaling factor of fuzzy controller.