Semi-active control of a passenger vehicle for improved ride and handling

Abstract

A theoretical model is developed for the semi-active control of the suspension of a full passenger car using a variable-structure-type algorithm. Skyhook control and variants of balance control (cancelling or adding the dynamic spring forces) are applied via a magnetorheological damper at the front and rear wheels to improve the vehicle ride and handling. The magnetorheological damper is modelled via a Bouc—Wen approach. The semi-active vehicle response is compared with a passive response. The robustness of control is established by adding noise to the computed sensor inputs, and the loose-wire scenario is also considered. The results show that balance control is a robust algorithm. The magnitude of acceleration reduction (for the human body and head—neck complex) using semi-active control varies with the semi-active approach and vehicle speed (a simulated random road was assumed). At 30m/s the human body acceleration reduction was found to be 70 per cent with skyhook control and 40 per cent with balance control (cancelling the dynamic spring forces). The handling manoeuvres of the vehicle are presented utilizing BS ISO 3888-1 1999. The handling performance of the vehicle is significantly improved, when balance control by cancelling is applied on the rear dampers only. Using skyhook control and balance control by adding a spring force to the system it is not possible to improve the handling response of the vehicle.