Abstract
A two-degrees-of-freedom vehicle model incorporating passive, active and semi-active suspensions was studied using analytical and simulation techniques. The trade-offs between the three performance criteria of ride comfort, suspension deflections and road safety were demonstrated for the different types of suspensions. The model is excited by random road irregularities which are represented by a filtered white noise. The results show that while substantial improvements in vehicle performance are achieved through the use of an active suspension, the active suspension is still compromised in satisfying simultaneously the three performance criteria.