The integrated control between the vehicle chassis subsystems (suspension, brake, and steering) became one of the most important aspects for current developments to improve the dynamics of the vehicles. Therefore, the aim of this study is to investigate the influence of the preview control of the active suspension on the vehicle ride and braking performance. The vehicle performance was examined theoretically using a longitudinal half vehicle model with four degrees of freedom considering the rotational motion of the tires. The active suspension system model, tire-road interface model and braking system model are included in the vehicle model.
In order to study the influence of the preview control on the vehicle ride and braking performance, an active suspension system control algorithm employing the lock-ahead preview information and the wheel-base time delay based on the optimal control theory is derived. On the other hand, the ABS control algorithm is designed based on the slip-control strategy. The vehicle ride performance is evaluated in terms of discomfort and road holding, while the braking distance and time is considered as evaluation criteria for the vehicle brake performance. The results are generated in the time domain to simulate the vehicle response during braking, while wheels are subjected to vertical road input. Comparisons between passive and active suspension systems in terms of ride and braking performance are discussed as well as correlated and uncorrelated active suspension systems. The improvement of the preview control of the active suspension system on the ride and braking performance is shown.
