Development Of Electro-hydraulic Servo Test Bench For Automotive Suspension Damper And Its' Measure And Control System

An important factor which impact automobile performance is vibration, and vehicle riding and handling stability performance and the fatigue life of automotive components is impacted badly by this vibration. In automotive vibration reducing, suspension acts the main part, and as a part of suspension, damper plays domiciliary.So it is very important significance to study and improve damper performance, and it depends on the development of testing technique. Now, in our country, the mechanical test bench used prevalently has some vices: only one test wave, big test error, difficult to achieve more operating condition test to meet the test criterion. Electro-hydraulic servo test bench mostly imported from abroad, cost highly. The aim of this paper is to develop an electro-hydraulic test bench for automotive suspension damper, whose function is perfect and price is low. This test bench can provide a variety waveforms including: sine, square, saw-tooth, random road surface. The servo performance of output relative to input is better, it can do many type tamper performance test in this test bench.This thesis adopts the hydraulic drive which is designed for SV-5 automotive damper electro-hydraulic test bench provided by manufacturer. By matching the high speed servo-valve, to realize the testing signals. While the hydraulic equipment has been fixed, the test bench frame and test clamp which meet the test intensity and rigidity are designed according to dampers testing journey and hydraulic equipment structure, and also insure that the design tolerance of structure is in the limit of testing allow errors, accordingly, achieve the installation and debugging.The electro-hydraulic servo control system of test bench is simulated in MATLAB SIMULINK in this paper. It is shown that the servo performance of output of test bench relative to input is very perfect. It is also indicated this test bench can provide a variety waveforms to satisfy damper performance testing. By simplifying the automobile model and building a quarter car model -bench vibration system, the further research about the matching of suspension rigidity and damp and appraise of convenience can be reached, which also furthest simulate the actual working condition of the damper. However, actually, hydraulic control system contains the characteristic delay. According to the table of frequency and phase difference which provided by the manufacturer, apply the method of combining the Smith phase forecast and PID control, compensate the delay, of system and optimize the performance of system.USB2088 data collection interface, PCI2306-DA and a variety of sensor have been adopted as the hardware of measure and control system in this project .By programming to simulate the test signal and collect data in LabVIEW software. When the action signal is send out by computer, it is amplified and modulated. Output is electric current signal which make hydraulic actuator moving according to required direction and velocity, meanwhile the damper move according to the actuator movement. The displacement, velocity, force and acceleration is measured by the sensor respectively. The signals are input to AD converter, required damper characteristic spot is gained by processing these data. Computer and measure & control system is used in test bench to automatic control test processing, and acquire test data, and make force-displacement and force-velocity plot of damper. The data and plot is saved and printed conveniently.