Development And Experimental Research On Fatigue Performance Of Electro-Pneumatic Inverter

Electro-pneumatic inverter is a kind of equipment that converts electric signal to pneumatic signal. It is the essential key device in many automatic process control system and mainly used in the field of high request for safety, such as: petrol, chemical, spin, paper making. It makes use of the converting principle of nozzle-flapper structure, adopts the piezoelectric ceramic composite plate as the actuator. Compared with the traditional mode, it is a breakthrough in easy controlling and the simple structure.The thesis mainly completed as follows:Designed the orthogonal experiment testing the performance based on the condition of request of inverter, and also made the repeat fatigue experiment, through the experiment, the significant factor-temperature and next significant factor-the way of voltage's change have been found, frequency and interaction between factors are the insignificant factors, so they can be ignored.With ANSYS software, have made the reliability analysis based on the main dimension of the flapper which is the main part of the inverter, calculated the sensitivities which influence the inverter's performance. Between the dimension of the inverter, the length of PZT(R1) is the highest, the next is the thickness of copper electrode(T2), the influence of them is negative, it indicates that they are reverse with the inverter's performance, the influence of the thickness of PZT(T1) is positive, it indicates that it is direct proportion with the performance, the relation between them is R1>T2>T1.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. As adopted close loop controlling, control intelligence, diagnose intelligence and protection intelligence are the remarkable characteristics of the system; control accuracy and the system credibility is greatly improved.Completed the static and whole testing of the inverter, it contains: whole precision, the performance of the steady transition and excursion of the inverter.