Pid Parameters Optimal Design For Plants With Time Delay

With the rapid development of science and technology, industrial systems further step toward intelligence, accuracy, safety and economical direction. As an evergreen in the field of automatic control, a classical PID controller, whether based on major computer platforms, or micro-processor platform, is still leader of automatic control. However, due to the existence of time-variety, nonlinearity, large time delay in the industries, it is difficult for the classical PID controller by tuned and designed based on model to achieve the accurate control objective. On the pace of the development of advanced control theory, a new chapter for PID controller is created. Therefore, combining advanced control strategies with PID controller, will bring a revolutionary breakthrough for the actual production.Recently, intelligent control is gradually affecting all aspects of human being’s life. By combining these control technology with PID controller, it not only covers the shortcomings of traditional PID controller, but also improves the control quality of control system. Actually, the PID controller design problem can be considered as a multi-objective optimization problem. The essence of design of PID controller is that satisfying the actual requirement, such as reference track, load disturbance attenuation, and robustness, by design the moderate PID controller parameters. Additionally, so for, the being published papers for PID controller design are based on the objective function optimization. It is relatively less about the PID controller’s parameters that whether have the stability region or parameter region satisfying the required performance or not for some plant. At last, as a footstone of modern control theory, controller design based on time domain state space method has been one of promising trend in the control field, therefore, PID controller design based on time domain state space is also an approach to broaden the design of PID controller parameters.In this paper, through study the above three thought for PID controller, three PID controller design methods are proposed, namely, a multi-objective robust PID controller design for industrial plant, an optimal robust PID controller design method in stability region, and PID controller design based on state compensation theory. Depending on output performance indices of closed-loop system, the3rd chapter proposed a multi-objective robust PID controller design method by transfer PID controller design method into a multi-objective optimization problem, and applies the method to control a CSTR system. The4th chapter mainly presents a novel PID controller design method in the stability region for process with time delay. According the frequency response of plant, the parameters region for PID controller are obtained, and the optimal PID controller are given by a hierarchical iterative gradient optimization algorithm. The5th chapter mainly study the state compensation theory, and the PID controller are transferred into a time-domain state form. This method overcome the sensitivity on the inner and outer disturbance of system and improve the robustness. In the paper, the advantages and disadvantages of the proposed methods are demonstrated by making some simulated experiment, and presents some questions and thoughts for PID controller in the graduate period, and simply give a direction to solve questions.