Research And Analysis On Electro-hydraulic Digital System Of Plastic Manhole Cover Testing Machine

Plastic manhole cover is commonly known as plastic cover, It is a green cover in recent years. It has many advantages, such as environmental protection, energy conservation, material saving, retrievability. But the corresponding special testing machine have not been developed, leading to the plastic manhole cover in market cannot meet the requirement of the using.In this paper, the research object is Plastic Manhole Cover Testing Machine. Its control system is designed, in view of the existing problems in the work process of universal testing machine. Digital valve is used to control the speed and pressure of system and achieve the purpose of speed and pressure compound control. Firstly, the paper introduces the developing situation of the plastic manhole cover testing machine and points out that the importance of good testing machine; Secondly, analysis the force situation of plastic manhole cover and set up the main functions of the testing machine, selects the digital direction flow valve, hydraulic pump, the hydraulic cylinder, sensors and other hydraulic components. Finally, set up mathematic model of the electro-hydraulic digital speed and pressure control system. Based on reasonable assumptions and approximate linearization processing, the time domain and the frequency domain properties analysis of speed and pressure control system are completed with MATLAB simulation software, and set up the experimental platform. PID correction link is increased to enhance the stability and response speed of control system further and ensure the improved control system could meet design requirements better.The analysis results and experiments showed that it is feasible to control the speed and pressure of system using digital valve.