THE ACTIVE SUSPENSION BETWEEN CUSTOMER BENEFIT AND TECHNOLOGICAL COMPETITION

This paper presents the attempts of BMW, in Germany, to define an appropriately designed active suspension system, based on vehicle dynamics measurement and subjective driver rating. It first surveys existing types of suspension systems systematically, and discusses the theoretical scope for their improvement. The following BMW vehicles were investigated: (1) a series production vehicle with active hydro- pneumatic suspension; (2) a test set-up with fully active suspension; (3) a test set-up with active hydro-pneumatic suspension; and (4) a different series production vehicle. Subjective and objective functional assessments were given of the following features of the vehicles: (1) vertical vibrational comfort; (2) handling (lateral and rolling movements); and (3) superimposed dynamics. The hardware requirements for active suspension are discussed. Finally, several findings are presented, based on measurements and on the subjective assessments of a considerable number of drivers. Customers seem to appreciate active suspension, if it is sufficiently effective. However, the costs of such suspension systems are still very high. For the covering abstract see IRRD 870290.