Research On Control System Of Cylinder Of High-Speed On-Off Valve Based On PWM

The pneumatic valve position servo system is one of the most importantcomponent which is used in petrochemical industry, electric industry, metallurgyindustry and so on in order to implement automatic control, increase producingefficiency and reduce producing cost. In this paper, a pneumatic valve position servosystem is described, which is made of switching valve and double-acting air cylinder,against to strong non-linearity and great frictional force when the velocity is slow,which has the merits of low cost, self-protecting against pollution while theproportional valve is worse. The experimental results show that the pneumatic valveposition servo system has acceptability positioning accuracy and stabilizing transient.The paper is made up of the following part:Firstly, the application and development of the pneumatic servo at home andabroad is analysed and addressed, such as the PWM and the work principle andcharacteristic of the high-speed on-off valve. Then, according to the theories of theelectromagnetic, circuit and hydromechanics, the transformer of the high-speed on-offvalve and valve control system is deduced. Finally, the convention PID and the Fuzzyadaptive PID is analysed and designed which will be simulated inMATLAB/SIMULINK respectively according the model of system that has been builtabove.Secondly, in order to build high-speed on-off valve PWM control systemhardware platform, the hardware system is designed, with a single-chip R8C2Lcontaining high resolution PWM module as its core. The signal from the displacementtransducer, which is compared with the reference signal then calculated by the Fuzzyadaptive PID control arithmetic, controls the duty ratio by which the on-off valve iscontrolled.Finally, the strategy of the Fuzzy adaptive PID control is tested in the platform.The result of the experiment suggested that the design of this system has great steadyand dynamic performance and the positioning precision is1mm and transient isless than5s.All the analysis show that the research of control system of cylinder ofhigh-speed on-off valve based on PWM is applicable, we will further improve this control method in the using of power station and other industrial applications.