Pose Trajectory Formation Mechanism for Corner Module Vehicles in Highway Lane-Changing Scenarios

The lateral motion of traditional vehicles cannot be actively controlled, but can only be realized through coordinated control of longitudinal and yaw movement. In highway lane-changing scenarios, an angle between the road tangent and the vehicle orientation must be created. This allows the vehicle to have a velocity in the road vertical direction, thereby the lateral displacement of vehicle relative to the road is generated. However, if the vehicle's lateral motion can be controlled actively, the angle between road tangent and vehicle orientation becomes unnecessary. The needless angle may generate adverse effects on driver visibility, vehicle stability and comfort. To solve this problem, this paper presents a pose trajectory concept for lane-changing, including longitudinal and lateral positions and yaw angles, using a corner module vehicle as the research subject. The kinematic and dynamic constraints of the vehicle are established. Considering lane-changing efficiency, lateral performance, yaw angle deviation from the road direction, and yaw performance, the optimization objectives are established. A particle swarm optimization algorithm is utilized to find the optimal trajectory of the proposed pose trajectories in highway lane-changing scenarios, and the traceability of the optimal pose trajectory is verified using model predictive control method based on a four-wheel steering vehicle model. Finally, the two optimal trajectories of the proposed pose trajectories and traditional position trajectories are compared. The results show that the proposed pose trajectories can reduce the yaw angle deviation and substantially improve vehicle yaw stability and comfort without reducing lane-changing efficiency.