High Density Automated Valet Parking via Multi-agent Path Finding

Improving the land use of parking lots is an essential component of good urban planning. To this end, many planners have introduced cooperative automated valet parking (Co-AVP) systems that realize high-density parking (HDP). Effective HDP requires the relocation of vehicles that blocks other vehicles from entering and leaving the Co-AVP. This paper proposes and solves a destination-assignment and path-planning problem for multiple vehicles with three roles: entering, leaving, and relocating. We minimize the total travel time of leaving vehicles and the total travel distance of entering and relocating vehicles from a service-policy viewpoint. We then propose two methods, integer linear programming (ILP)-based and conflictbased search (CBS)-based, for solving the problem. Numerical experiments demonstrated that the ILP-based approach scales better than the CBS-based approach. We also confirmed the applicability of our approaches to realistic parking situations.