Parameters Tuning Of PID Controller

PID (Proportional,Integral and Differential) controller is widely used in kinds of industry circumstance for its simple structure,easy implementation and strong robustness. Because of the difficulty of modeling the industry plants and the frequent change of the parameters of plants, we often couldn't get optimal control effects by using common PID controllers. In application, excellent tuned parameters of PID controller are the precondition of good closed-loop control effects. So it is significant to find the tuning methods which are simple, practical and have good performance.An overview of the current status in PID controller parameters tuning method is presented. The PID controller tuning methods for different plants is discussed mainly. The work of this paper follows as below:For the existence of right-half-plane (RHP) zeros in the non-minimum phase plus dead time system, there is an under-shoot in the closed-loop response. At the same time the dead time in the system deteriorates the performance of control system and makes the under-shoot more obviously. A design scheme of PID controller for non-minimum phase plants plus dead time system based on Smith predictor is proposed. Both right-half-plane (RHP) and dead time can be compensated. The RHP zeros and dead time are removed from the characteristic equation so that the control design is greatly simplified. The parameters tuning rule is also presented. To improve the poor disturbance-rejection performance of Smith predictor, a feedback controller is added to the scheme.Robust PID control based on internal model control (IMC) can provides good setpoint response performance and poor disturbance-rejection performance for the system. Aiming at good disturbance-rejection performance a robust PID control method which based on IMC is proposed. To gain good setpoint response and disturbance-rejection performance, an adptive robust PID control method based on IMC is proposed. And the parameters of PID can be changed according to the demand of the system by using the proposed method.The experiment of level PID control system of oil and water separator is done .The proposed PID parameter tuning methods are applied to the equipment and the results of the application show that the proposed methods provide good setpoint response and disturbance-rejection performance.