Research On Control Methods Of Vehicle Active Suspension

Vehicle Active Suspension appears that has been payed close attention to, because the suspension performance has influence on ride quality and drive safety. With vehicle ride quality rising, the research on active suspension control has developped quickly as well. As we known, although the phyical structure of suspensions are the same, different control methods bring different control performance. Because of the system complexity, time-varying and uncertainty etc, the study and refinement of active suspension control methods have been proven to be very significant, this paper starts work to meet the needs.This paper has four chapters, in chapter 2 the phycial structure of suspension system and the mathematics expression of that have been studied deeply. Usually the vehicle model has been grouped into three types, 7 DOF (Degree of Freedom) whole vehicle model, 4 DOF half-car model and 2 DOF quarter-car model. To meet the research need we chose one of them, in this paper we chose 2 DOF quarter-car model to study the suspension system performance effected by the heave disturbance from road surface. The road disturbance models alse have been discussed in this paper, including the white-noise road disturbance model and bump roud disturbance model.In chapter 3, PID controller has been designed and simulated in matlab both in time domain and frequency domain. In chapter 4, constrained MPC (Model Predictive Control) controller has been studied from its stability to its solution procedure step by step. Take the vehicle body heave acceleration , suspension deflection and tire deflection as the performance index with weight coefficients, and the suspension deflection and control force as the constraints to reach the better ride quality. Analysed suspension system performance effected by the predictive time span, so as the weight coefficients.