Spatio-temporal heuristic method:a trajectory planning for automatic parking considering obstacle behavior

Purpose–The purpose of this paper is to develop a real-time trajectory planner with optimal maneuver for autonomous vehicles to deal with dynamic obstacles during parallel parking.Design/methodology/approach–To deal with dynamic obstacles for autonomous vehicles during parking,a long-and short-term mixed trajectory planning algorithm is proposed in this paper.In long term,considering obstacle behavior,A-star algorithm was improved by RS curve and potential function via spatio-temporal map to obtain a safe and efficient initial trajectory.In short term,this paper proposes a nonlinear model predictive control trajectory optimizer to smooth and adjust the trajectory online based on the vehicle kinematic model.Moreover,the proposed method is simulated and verified in four common dynamic parking scenarios by ACADO Toolkit and QPOASE solver.Findings–Compared with the spline optimization method,the results show that the proposed method can generate efficient obstacle avoidance strategies,safe parking trajectories and control parameters such as the front wheel angle and velocity in high-efficient central processing units.Originality/value–It is aimed at improving the robustness of automatic parking system and providing a reference for decision-making in a dynamic environment.