Exploring Four-Wheel Steering for Trajectory Tracking of Autonomous Vehicles in Critical Conditions

The advent of autonomous vehicles (AVs) enables the utilisation of by-wire technologies, which can be employed for various purposes, including four-wheel steering (4WS). The integration of 4WS into AVs has the potential to enhance vehicle performance in terms of manoeuvrability, stability and path tracking. This research aims to investigate the application of 4WS in the trajectory tracking of AVs in critical driving conditions. The trajectory tracking problem is formulated within the framework of model predictive control (MPC). The performance of 4WS is examined through comparative analyses with two alternative steering configurations, namely, active front steering (AFS) and a combination of active front and rear steering (AFS+ARS). This evaluation is performed by using three types of reference trajectories, which are generated based on the AFS, AFS+ARS and 4WS configurations. The findings indicate that the 4WS configuration enhances vehicle safety, passing velocity and tracking accuracy.