Electric-Pneumatic Valve Positioner Model Identification And Control Optimization

Electric-pneumatic valve positioner is an important part in the control process of regulating valve.It plays an important role in pipeline flow control,improving control characteristics of regulating valve system.At present,PID algorithm is widely used in electric valve positioner,but it is difficult to obtain highquality PID parameters by conventional PID parameter setting method,and the process of artificial intelligence algorithm to optimize PID parameters is complicated and difficult to complete online.In this paper,the model identification and control system optimization of the electric-pneumatic valve positioner are studied.The specific contents are as follows:Firstly,the operating characteristics and model characteristics of the system are analyzed in this paper,combined with the open-loop step response of the system,the FOPDT model was used to represent the electric valve positioner system.On this basis,the hardware circuit design scheme is proposed.By comparing conventional system identification methods,the area method is determined as the system identification method in this paper.Secondly,aiming at the problems of large overshoot and long adjustment time in the PID control process of electric valve positioner,relay feedback method is selected to determine the PID parameter optimization range,and a PID parameter optimization scheme based on improved genetic algorithm is proposed in this paper MTALAB/SIMULINK simulation verifies that the PID parameters obtained under this scheme can make the system obtain more stable dynamic and static performance,and achieve the control requirements of stable,accurate and fast.Finally,in view of the complex process of genetic optimization PID parameters and large memory consumption,a large number of high-quality PID parameters are generated and stored in offline mode,and a PID parameter database is established.Online system identification and PID parameter query are used to achieve efficient online PID parameter setting.Experimental platform entity valve set show that the system overshoot amount can be controlled in 0.6%,adjust time control in 8 s,rise time control in 3.7 s,PID parameter database query results are basically consistent with the response of the optimal solution,shows that this paper establish procedures for PID parameters database can shorten computation,reduce the power consumption of the main control chip and guarantee the quality of PID parameters.This paper provides a new idea for optimizing the control strategy of electric-pneumatic valve positioner.