This paper proposes autonomous parallel parking for a front-wheel steering vehicle, with highlights on a trajectory planning method and on a trajectory tracking control method. The trajectory planning problem is decoupled into the path planning problem and the longitudinal velocity planning problem to reduce the difficulty of the trajectory planning problem. First, a collision-free path by combining circle arcs with straight line is created to park the vehicle in one or more maneuvers on the premise of meeting the kinematic constraint of vehicle, and then the path is transformed into a continuous-curvature path using B-spline curve. Second, the longitudinal velocity is created using B-spline curve on the premise of meeting the performance constraints of driving and braking system. To execute the generated trajectory, a non-time reference path tracking sliding mode control strategy is deduced by Lyapunov stability theory, and a longitudinal velocity tracking proportional–integral control strategy is proposed based on smooth handoff method. Finally, the parking performance is verified based on model-in-the-loop simulation system.
Trajectory planning and tracking control for autonomous parallel parking of a non-holonomic vehicle