The dynamics of vehicles became one of the most important aspects for current developments of electronically controlled steering, suspension and traction/braking systems. However, most of the published research on vehicle maneuverability doesn't take into account the effect of the dynamic tire load and its variation on uneven roads.
Clearly, it was stated that using a suitable active suspension system could reduce this dynamic tire load. This dynamic tire load is playing a vital role as it is the major link between the vertical and lateral forces exerted on the road, which affects the lateral dynamics of the vehicle.
In this paper, a practical hydro-pneumatic limited bandwidth active suspension system with and without wheelbase preview control is used to study its influence on the vehicle stability in lateral direction. The model is a longitudinal half car with four degrees of freedom. Vehicle lateral dynamics is modeled as a two degrees (yaw and side slip) bicycle model and a driver model. The controllable suspension system is deigned based on linear optimal control theory using LQR control technique with front to rear axle preview is taken into account. The interaction between the performance of active suspension and vehicle lateral dynamics is studied through a non-linear Magic Formula tire model.
The results are generated in the time domain to simulate the vehicle response in handling maneuvers while road wheels are subjected to vertical road input. Comparisons between passive and active suspension are discussed as well as correlated and uncorrelated active suspension systems. The improvement of active suspension on maneuverability and stability is shown.