The Design Of PID Controller Based On Internal Model Control Theory

PID control, as a kind of control method in automatic control, is produced the earliest and used for the widest range of application. This paper starts with surveying the advanced PID parameter tuning methods and the newest achievements in this subject. Next, based on PID control's structure, the need of practical control engineering and the realizable conditions, it is analyzed that PID control's special advantages and the theoretical argument. In most PID tuning rules, method of internal model control (IMC) tunings is investigated. The PID controller is designed by using the equivalent feedback structure, and the theoretical results of PID parameters can be obtained. A new PID tuning method is presented for an industrial process control plant (the first-order or second-order pure delay process). A double loop structure is employed to a class of unstable process with time delay. After selecting the P controller to stabilize the inner loop, the IMC principle is used to design the main feedback controller . The design procedure of the two-degree-of-freedom (2DOF) PID controller is presented for these processes. The designed controller has only two adjustable parameters that are directly related to system performance. In this method a good dynamic response performance of both objective tracking and disturbance rejection can be achieved simultaneously. The simulation shows that this method has not only high robustness, but also good expeditiousness and flexibility, and it is fit in with engineering applications. At last, it also points out the directions of the future development.