Trajectory Planning, Dynamics Modelling and Trajectory Tracking Method for Off-Road Autonomous Vehicles Considering the Road Topography Information

The road topography can significantly affect the tyre vertical load and the vehicle dynamics response in off-road scenarios, which will greatly impact the autonomous vehicle's stability, trajectory planning and trajectory tracking performance. However, the road topography information is less focused in current literature. This study focuses on the local trajectory planning and tracking method by assuming waypoints along the global route are already available. First an innovative spatiotemporal-based local trajectory planning algorithm is proposed to select the desired trajectory with minimum road gradient and bank angle. After that, a 8 degrees-of-freedom (DOF) vehicle dynamics model is proposed to better present the dynamics performance. Finally a double-layer control strategy for trajectory tracking is designed to follow the desired planned trajectory. It is proved by simulations results that the peak bank angle and road gradient could be avoided, and the trajectory tracking performance is improved by the proposed method. Furthermore, the omni-directional vehicle is shown to have better vehicle stability performance than the vehicle with front-wheel steering (FWS) characteristic.