• CN: 11-2187/TH
  • ISSN: 0577-6686

Journal of Mechanical Engineering ›› 2023, Vol. 59 ›› Issue (24): 290-298.doi: 10.3901/JME.2023.24.290

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Hierarchical Motion Planning Method Based on Hybrid A-star for Cruising in Parking Area

ZHAO Jintao, LI Liang, XUE Zhongjin, ZHANG Zhihuang   

  1. State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing 100084
  • Received:2023-06-05 Revised:2023-10-25 Online:2023-12-20 Published:2024-03-05

Abstract: As an important part of the intelligent transportation system, autonomous vehicles have received more and more attention from researchers. Auto valet parking is an essential part of high-level autonomous driving. As valet parking is applied to unstructured environments, researchers need to design special planning algorithms to deal with the various challenges of unstructured scenarios such as the lack of road lines, and the uncertain forecasts of surroundings. Considering the environmental characteristics of valet parking, a hierarchical motion planning method based on an improved hybrid A-Star algorithm and a time elastic band algorithm is proposed. By modifying the collision detection process, the hybrid A-Star algorithm can achieve interactive behavior. By introducing the cost of the reference line, the search efficiency of the hybrid A-Star algorithm is improved. The improved hybrid A-Star algorithm can generate reasonable and effective initial trajectories for unstructured environments. The time-elastic-band algorithm has high execution efficiency, effectively solves the problem of vehicle kinematics and obstacle constraints, and can quickly respond to environmental changes. A real vehicle experiment is carried out in Suzhou, China. The results show that the proposed algorithm can effectively solve the problem of vehicle lateral motion planning in conventional scenarios.

Key words: auto valet parking, motion planning, hybrid A-star, timed-elastic-band

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