Design And Research On The Controlling System Of Piezoelectric-driven Flow Valve

With the development and application of micro precision fluid control technology in the area of aerospace,deep-sea exploration, accurate mix substances system in medicine, defence and military, high-pressure microfluidics control technology is expected more to meeting the demands of the small system in mass,volume and a higher system performance. In order to control the flow of the piezoelectric-driven flow valve,a high precision fine-tuning for the valve spool is required. A controlling system of piezoelectric-driven flow valve is designed.The piezoelectric ceramic is a kind of high-precision positioning actuator. Firstly, the implementation of controlling system of piezoelectric-driven flow valve is proved to be reasonable through analyzing the principle of piezoelectric-driven flow valve; Secondly,based on the principle of voltage-controlled piezoelectric ceramic driving power, a high precision piezoelectric ceramic drive has been designed by using a high-voltage operational amplifier circuit consisting of amplifier PA90 and OPA277 P.The test results show that this matching circuit is with some marvelous features like good linearity, low voltage ripple and fast dynamic response and high reliability; Finally, a software program which is aim to eliminate the nonlinearity,the uncertain in some degree of the piezoelectric ceramic,solves the difficulties to obtain accurate mathematical model of the piezoelectric ceramic and applies to control the system is designed.In the end, a closed-loop experimental control system is established, by using a data acquisition card to acquire voltage data, by the mean of using a laser displacement sensor to measure the displacement of piezoelectric ceramic and through the sensor controller output a displacement signal to the data acquisition card.Through the test of open loop output characteristics of piezoelectric ceramic and closed-loop control precision of the control system and comparing the result of the PID control experiment and fuzzy PID control experiment, the experimental results show that this system has small overshoot, high control accuracy, short adjusting time,fast dynamic response and low steady error.