The Research And Design Of Multiplex Proportional Valve Control System

With the development of industrial automation, higher requirements of the hydraulic control system have been put forward by each industry. In the era of digital circuits, digital circuits occupy the most of the market with its advantages such as its easy implementation, reliable system, high integration, easily realizing functions and so on. So, the digital proportional controller has become a trend in today’s proportional controller area because of its high control precision and good performance.The traditional electro-hydraulic proportional valve control system is usually realized by PID(proportion, integration, differentiation) control technology. However, this control technology cannot meet the demands in industry with requiring of higher control performance. Aiming at the shortcomings of the traditional control technology, this paper introduces a kind of method which can realize controlling multi-channel proportional valve. The method adopts the model of constant current control. This can achieve faster response and higher control precision.This system adopts the STMicroelectronics company’s product STM32F103VET6. The chip is based on the Cortex-M3 kernel. It is a 32-bit processor. The core control chip communicates with PC through serial port. Via serial port, the upper machine can control the hardware system. At the same time, the hardware system collects the current values by control chip then sent to the PC. The PC can display it. The core chip stores the correction in its internal flash memory for the purpose of better control effect. The hardware part includes power supply module, control module, multi-channel realizing, adjustment of PWM, driver module and so on. This paper introduces the realization of adjusting the duty of PWM, full bridge drive and collection of current in detail. The software part includes the software of core chip processor and PC control interface. This paper introduces the direct digital frequency synthesizer and the data correction through linear interpolation. At the same time, this paper introduces how to use virtual instrument Lab Windows/CVI to develop graphical user interface. Through the modular design, this system has realized the constant current mode control of electro-hydraulic proportional valve. The advantages of this system are low consumption, low cast, strong anti-interference, etc.