PID Controller Parameter Tuning Method And Application

PID controller is widely applied in various industrial process-control because of its simple structure,strong robustness,and easy practicability.As a widely used control rule,PID control is still occupied a dominant position in a variety of control technology.With the improvement of production process and more and more complex process control environment,control plant appears the large time delay,nonlinear,and multi-interference factors.PID parameter tuning has attracted more and more attention.It has become an important research topic in the field of automatic control.Performance indicators are used to evaluate performance of the control system,the system used individual performance indicator which reflected steady,accurate,and Response speed,such as overshoot,settling time,rise time and steady-state error,also used the comprehensive performance indicators,such as the square take time error integral ISE and IAE ITAE.In this paper,performance calculation function perfor.m was compiled based on MATLAB,it's convenient when the controller design simulation process response curve calculated for different control systems.Methods of Taylor approximation,all-pole approximation and Pade approximation are adapted to processing and analysis the exist delay of first or second order control object.From the fitting effect,it shows that Pade approximation method is better than the other two methods,and the higher order Pade approximation,the better result of pure delay stages and more smooth curves are.According to the control performance,All-pole approximation is the best.The simulation design of Classic PID parameter tuning methods,including Z-N critical proportional method,Z-N empirical formula method,relay self-Tuning,C-C method and the best Tuning,are also studied.All those tuning method is only applicable to first-order system,and in order to meet the optimum overshoot engineering applications(?%<5%),the three parameters of classic PID need to be adjusted manually.IMC-PID controllers for eight common analog control objects are also designed.Both robust performance and dynamic performance of the value of M and ITAE index value are adapted to turning X parameter of IMC-PID.It shows that when delay time increasing,value of ? increases.The second IMC-PID can be well controlled.