Study Of Temperature Drift Characteristics Of Servo Valve And Its Testing System

Servo valve is mainly used in the field of military and its characteristic parameters are must very stable to ensure the control accuracy of system. Affected by the oil temperature, the work zero of servo valve will be changed, which has a great impact on the control accuracy of the system. It is a very important link to test the temperature drift of servo valve before leaving the factory. There are many equipments needed in the existing testing device and the results are mainly through the experimental personnel, which will lead to the low efficiency, poor stability and poor accuracy.This thesis is based on the project of a Space Research Institute.It is designed to develop a servo valve computer aided test system, which is applied to test the temperature drift parameter of the servo valve.This thesis mainly studies the temperature drift of a certain type of force feedback two stage servo valve and its automatic test system. Firstly, the temperature drift characteristic parameters of the servo valve are introduced, and which belongs to the closed-loop control system of the hydraulic position.The mathematical model of servo amplifier, servo valve and valve cylinder is established, and the transfer function block diagram of the test system is obtained.Then, the research on the control algorithm of the test system, the calculation of temperature drift value and the current sampling circuit of the servo valve are studied.Respectivly, analysis of the influence of temperature change on the torque motor, the valve nozzle flapper and slide valve, which how to change the operating point of the servo valve. Secondly according to the requirements of the servo valve temperature drift characteristic parameter testing, mechanical testing station, and signal conversion circuit are designed. Beside based on the platform of C#in VS2010environment complete PC interface programming. Finally, the test results of the temperature drift of a two stage servo valve with the force feedback are analyzed.Results show that the design of servo valve temperature drift characteristic parameter testing system greatly improve the test efficiency, test precision and stability. What’s more, it also fully reflects the servo valve under different temperature bias.