Development Of Electro-hydraulic Servo Test Bench For Automotive Suspension Damper

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. There are three parts which damp vibration: tyre, suspension and seat. Suspension system contributes most in these three parts, and damper contributes most in suspension system. So it has very important significance to improve vehicle riding performance and automobile quality by improving damper performance. When designing damper, the design result and practice effect is must be validated by examination, so the development of damper designing technology depend on the development of testing and examination technology.The mechanical test bench used prevalently some vices: only one test wave, big test error of displacement and velocity, little bound of test velocity, bad contrast of test result, difficult to achieve more operating condition test, and so on. The function of electro-hydraulic servo test bench is perfect, but its price is very high. The most aim of this paper is developing 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.A computer and a data collection clip are used to measure and control in this test bench. The action signal of test bench is send out by computer, and the signal put intoservo controller via digital analog converter, with which the signal is magnified 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 and force is measured by displacement sensor, velocity sensor and force sensor respectively, and these displacement signal, velocity signal and force signal are input analog digital converter. The required damper characteristic spot is gained by processing these data. The technology of microcomputer measurement & control and electro-hydraulic servo is use in this designing course, realizing real-time examining and closed loop controlling by simulating damper practical operating condition.The electro-hydraulic servo control system of test bench is simulated in MAT1AB 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. It is shown that this test bench can test not only single damper but also simplified automobile model by establishing test bench and quarter car body model.Computer and measurement & control software is used in test bench to automatic control test processing, and collect test data, and make force-displacement and force-velocity plot of damper. The data and plot is saved and printed conveniently.