Global integrated control of vehicle suspension and chassis key subsystems

This paper presents a new integrated control methodology for vehicle chassis subsystems associated with controlled suspension, braking system, and steering systems. In order to reflect the practical vehicle better, a non-linear complicated full-vehicle model which includes longitudinal, lateral, and vertical dynamics is established and combined with the modified non-linear tyre model. Then, a main objective-oriented hierarchical control strategy is proposed for global integrated control of chassis subsystems to improve the vehicle performance during different kinds of driving condition. The proposed hierarchical strategy consists of two layers. The upper layer is a system supervisory layer which is used to identify the vehicle states and to assign the task for each controllable subsystem based on their effective regions and the detected state signals of the system. The lower layer is the executive layer interfaced to actuators of the chassis subsystem. In this layer, different controllers which can be switched to a special vehicle state are designed by using fuzzy control and integral sliding-mode control methods. The effectiveness of the proposed control strategy is verified via computer simulations, showing the results of three typical driving conditions.