Design Of Experimental Platform And Research On Control Strategy Of Pneumatic Regulating Valve Based On LabVIEW

As an essential terminal actuator in industrial production process,pneumatic regulating valve's control performance will directly affect the product quality and safe operation of the whole production system.And as the core accessory of the regulating valve,the intelligent valve positioner can effectively improve the action characteristics of the regulating valve and improve the accuracy and speed of valve position control.Therefore,the improved research on the intelligent valve positioner is very important.Based on this situation,we take ZJHP pneumatic regulating valve as the controlled object,build an experimental platform of valve position control system,and focus on the internal control algorithm of intelligent valve positioner.The main research work of this thesis is as follows:(1)On the basis of deeply understanding the working principle of the valve positioner,we analyze the mechanism characteristics of each component of the valve position control system and obtain its overall model.And considering the difficulty of obtaining the mechanism parameters in the actual system,the first-order inertial hysteresis model commonly used in industrial control is used to approximate the system to facilitate subsequent simulation research on the control algorithm.(2)An experimental platform for pneumatic control valves based on LabVIEW is built.Firstly,according to the working principle of the valve position control system,we construct the hardware connection structure with industrial computer as the core,and then we design the platform LabVIEW function program by modules.Finally,the valve position process data collection and real-time control are realized through the cooperative work of software and hardware.Afterwards,an open-loop control experiment is carried out on the regulating valve using the experimental platform,and the actual input and output data of the valve are obtained.Combined with the MATLAB identification toolbox,the valve position control system is identified,and the specific parameters of the system model are finally obtained.(3)In view of the balance requirements of the valve position control system for accuracy,rapidity and stability,we select human-like intelligent control as the prototype of the valve position control algorithm.And aiming at solving the problems of the basic human-simulating intelligent control that the initial control of modal switching is not timely and the overall intelligence is insufficient,we propose a fuzzy reasoning-based differential action human-simulated intelligent control algorithm.Simulation analysis and platform experiment verification show that this algorithm is superior to PID and basic human-simulating intelligent control algorithms in terms of regulation time,overshoot and other performance,and shows stronger anti-interference and robustness,which can effectively improve the control accuracy of the regulating valve.