| In this paper, the dynamics property of the suspension system has been theoretical analyzed, and the control technology of the semi-active suspension system is been studied both in time domain and frequency domain. At the same time, the software and hardware design and realization of the suspension control system are discussed. The major research work of this paper are:(1)The frequency response and step response property of the suspension have been analyzed, and the influence effect of suspension system performance to damping varing is revealed.(2) Describing function method has been used as the analytical technique to study the nonlinear semi-active suspension control system. And the DF analysis method has been realized using Matlab and Simulink.(3) Guass white noise filtered road profile model has been analyzed, and A~E grade road profile have been realized using Matlab and Simulink. The spectrum analysis has been done for the time domain simulating result of the road profile employing FFT technology.(4) Skyhook control, ON-OFF control which is based on skyhook control thought and fuzzy logic control have been studied and the time domain and frequency domain simulation programme was realized using Malab high-level language, Simulink and corresponding toolbox. The results show that Skyhook control, ON-OFF control and fuzzy control can improve ride comfort at the premise of reasonable tire deflection and suspension deflection.(5) The ride quality of the vehicle has been evaluated using frequency weighted mean square root method according to national standard GB4970 and the evaluation programme was coded in Matlab high-level language.(6) The realization of the suspension control system are discussed and the real-time embedded OS μC/OS-II was ported to DSP to improve the stability of control system. And experiment was taken out for the semiactive suspension control system. |
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