Digital amplifier for proportional directional valve with position feedback

CHEN Feifei1, XV Hui2, WANG Shijie2, JIN Bo2, ZHANG Lulu2

(1.Ningbo HOYEA Machinery Manufacture Co., Ltd., Ningbo 315131, China;
2.State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou 310027, China)

Abstract: Aiming at the development status of the amplifier for proportional valve and the control requirement of proportional directional valve, the control principle of digital amplifier for proportional directional valve(DAPDV) was analyzed and the system model of proportional directional valve was established. After the theoretical analysis, a DAPDV based on ARM7 micro-controller and the technology of the inverse-relief power driver circuit was implemented. With the aid of Visual C++ and ADS1.2 integrated development environment, the software system of the proportional amplifier was developed. The human-machine interface of host computer was designed, and the program control and close loop control of the proportional valve was realized. After determining the PID parameters of the proportional amplifier, the step response and sine wave signal response of the proportional directional valve system were tested on the electra-hydraulic proportional experiment rig. The results indicate that the system setting time for step response is short, the frequency response bandwidth is enough, and the designed proportional amplifier has good stability and dynamic performance.

Key words: digital proportional amplifier; mathematical model of proportional directional valve system; ARM; inverse-relief power driver circuit; human-machine interface