Real-Time Trajectory Planning and Tracking Control of Four-Wheel Steering Vehicles

Four-wheel steering vehicles exhibit exceptional controllability, flexibility, and mobility, making them highly suitable for inspection tasks in complex environments. Research on trajectory planning and trajectory tracking for such vehicles is crucial for achieving efficient and precise inspection operations. To ensure that the planned trajectories align with the actual vehicle dynamics and enable effective navigation in narrow, obstacle-filled spaces, we first derive the kinematic model of the four-wheel steering vehicle. By leveraging the differential flatness property of the four-wheel steering vehicle, we simplify the trajectory representation and design an objective function to incorporate vehicle motion constraints. Additionally, we apply collision constraints using safe driving corridors to achieve efficient obstacle avoidance. Optimal trajectories and corresponding control inputs are computed through gradient descent optimization. To effectively track the planned trajectories, we construct a state-space transfer equation based on the kinematic model of the four-wheel steering vehicle and optimize the control output using quadratic programming. Experimental results demonstrate the effectiveness of the proposed planner and controller, highlighting the significance of this method in improving operational efficiency, trajectory smoothness, and control accuracy. This work provides a robust foundation for further advancements in autonomous navigation systems for four-wheel steering vehicles.