Structural Optimization Of The Piezoelectricity Electric-pneumatic Conveter And The Study On The Control

Electro-pneumatic converter is a kind of equipment that converts electric signal to pneumatic signal, and is the essential key device in many automatic process control system. Piezoelectric electro-pneumatic converter is an improvement of the membrane electro-pneumatic converter. It makes use of the converting principle of nozzle-flapper structure, adopts the piezoelectric ceramic composite plate as the actuator. These make it makes a breakthrough in the traditional mode. It's simple structured and easy to control.This thesis mainly completed two parts: The first is Parameter optimization of the Piezoelectricity electric-pneumatic conveter air course. the second is the hardware and software design of the converter's intelligence control system.As actuator was the piezoelectric bimorphs,electric-pneumatic transfer device with new piezoelectric structure was designed.The paper introduced the structure and the principle of the transfer device, analysised the key parameter and built orthogonal experimental design form.Base on the FLUENT, the Parameter optimization to the whole air course was carried on.The characteristic curve for the flapper gap to the back pressure was drawn.The key parameter of the nazzle was definited. The experiment proved that the parameter was reasonable, linearity was fine.Emulation laid the stone for the development of electric-pneumatic transducer valve and electric-pneumatic positioner valve with new piezo- electric structure.The intelligent control system of the electro-pneumatic converter is developed. The super low dissipation microprocessor MSP430F149 is the kernel of the control system. The control task is accomplished by software as well as hardware. The control method adopts the analog and digital closed loop control, using the techniques of software filter, digital PID control. Control intelligence, diagnose intelligence and protection intelligence are the remarkable characteristics of the system; it improves control accuracy and the system credibility greatly. Through the static testing and whole machine operation,the results show that the structure is reasonable, control system is reliable.