Application And Design Of Intelligent Valve Positioner Control System

As a key accessory of pneumatic control valves,valve positioners improve the response speed and adjustment accuracy of pneumatic control valves.Pneumatic control valves are now widely used in various industrial sites.In order to meet various complex and accurate control requirements,valve positioners have also become necessary accessories.Due to the mature technology of foreign enterprises and the late start of domestic research,most of the domestic valve positioner market is occupied by well-known foreign brands,so the research on intelligent valve positioners still needs to continue.This thesis studies and designs an intelligent valve positioner to achieve its function of adjusting the valve position based on input set signals.In terms of hardware design,the STM32L476RGT6 ultra-low power chip is used as the control core.The selection of the I/P conversion module,displacement sensor module,and chips of various modules on the circuit board is carried out.The hardware circuits of the power supply module,current acquisition module,displacement feedback module,display module,key input module,and PWM output module are designed.During the software design,the UCOSIII real-time operating system was transplanted,and the drivers’ codes for peripherals such as timers,analog-to-digital converters,general-purpose input and output,and LCD controllers were written.The low-power operation tasks,key input tasks,display tasks,parameter setting tasks,and valve position control tasks were designed.When studying the valve position control algorithm,the mathematical model of the pneumatic control valve control system is established using Simulink software.By analyzing the process of valve position movement,the flow equation,gas chamber thermodynamic equation,and mathematical model of valve stem movement of piezoelectric valves are established.PID algorithm is selected as the valve position control algorithm,and particle swarm optimization algorithm is used to fill in parameter simulation calculations for the system model during the parameter tuning process.By improving the particle velocity calculation method of particle swarm optimization algorithm and designing a fitness function,the optimal PID algorithm parameters are found,and finally verified on an actual pneumatic control valve.