| Shock absorber is one of the automobile's most important components.The quality of shock absorber directly relates to safety and comfort whilethe automobile is running. At present, the method to evaluate the quality ofa shock absorber is to vibrate one tire by a multi frequency test-bed. Theadhesion data and the damping parameter tested from the experiment candecide whether the quality of the shock absorber is good or bad accordingto Euro Shock Absorber Association. The advantage of this method is thatthe automotive model is simplified while the test system is accurate andreliable. The disadvantage of this method is that the automotive model iscoupled and the price of the test-bed is too high.This subject is supposed to find out a new test method to decidewhether the shock absorber is broken. Firstly, it established the vibrationmechanical of seven degrees of freedom vehicle and mathematical modelof seven degrees of freedom vehicle. Then the subject designedexperimental road-block. The mathematical model was simulated in Matlabsoftware. The response time of vertical displacement and acceleration ofvehicle body and tires were solved by corresponding simulation software, while the damping parameter was changed. The data from the simulationwas also analyzed in frequency domain.The subject carried out an experiment to confirm that the new methodwas valid. Siglab 20—42 multi-channel dynamic signals analytical systemwas used as data acquisition module. The data from the result of theexperiment was saved in Matlab Work Space and used FFT to transformthe data to frequency domain to analysis. The result of the experiment wascompared to the result of simulation, by which the new test method wasproved valid.
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