Design On Controller Of Electro-hydraulic Proportional Flow Valve

Proportional hydraulic control technology combines the advantages of electrical control and Hydraulic transmission. It is one of the core technology of mechanical engineering. With the rapid development of electronic technology, electro-hydraulic proportional control technology has been formed hydromechatronics, intelligence, and network of a trend. With the development of Proportional technology development, proportional control amplifier of one of its main direction. Currently, Analog amplifier is also widely used to control proportional valve on the market. This paper is to direct at the current situation, Through deeply research the developing process of electro-hydraulic proportional control amplifier and the current situation and the future trends of development trends in this paper. It design a digital and reliability proportional control amplifier. It is based on ARM7 control and do much research.The design of the project ARM7 digital proportional amplifier is based on LPC2290 for its processor, it is also expanding the interface circuit of proportional valve. So as the power amplifier circuit, sensors measuring circuitand so on. Power amplifier using PWM-charged anti-unloading proportional solenoid drive power amplifier to improve the dynamic response of proportional solenoids, and also thinking of using software instead of hardware, software programming to achieve the flutter signal superimposed on the PWM control signal. Measurement sensor conditioning amplifier circuit used a chip AD698 to achieve the spool displacement signal into the DC voltage signal. It is greatly simplified the hardware design and improve system reliability to use a Specific integrated chip.Digital proportional amplifier software design is based on uc/OSⅡreal-time operating system. The software sub-module is designed to multi-task. Between tasks carried data by global variables and data mailbox. System uses the PID control algorithm. It through the A/D conversion circuit, the analog signal and spool displacement feedback signals chansform the digital quantity. The digital singal is to filter operation and PID operation, then it output PWM signal to control. PWM singal chansform current signal to control proportional value by the anti-power amplifier circuit.It built a Experimental platform to control the Proportional flow control valve based on Rexroth TS-DS4. It tested the system hardware and software. And used different control algorithms to compared. Experimental results show that the controller's hardware and software wsa to correspond with the functions and requirements of the proportional valve controller. The system stability and Control effect is good.