Improved Heuristics for Multi-Agent Path Finding with Conflict-Based Search

Improved Heuristics for Multi-Agent Path Finding with Conflict-Based Search

Jiaoyang Li, Ariel Felner, Eli Boyarski, Hang Ma, Sven Koenig

Proceedings of the Twenty-Eighth International Joint Conference on Artificial Intelligence
Main track. Pages 442-449. https://doi.org/10.24963/ijcai.2019/63

Conflict-Based Search (CBS) and its enhancements are among the strongest algorithms for Multi-Agent Path Finding. Recent work introduced an admissible heuristic to guide the high-level search of CBS. In this work, we prove the limitation of this heuristic, as it is based on cardinal conflicts only. We then introduce two new admissible heuristics by reasoning about the pairwise dependencies between agents. Empirically, CBS with either new heuristic significantly improves the success rate over CBS with the recent heuristic and reduces the number of expanded nodes and runtime by up to a factor of 50.
Keywords:
Agent-based and Multi-agent Systems: Multi-agent Planning
Heuristic Search and Game Playing: Heuristic Search
Planning and Scheduling: Search in Planning and Scheduling
Heuristic Search and Game Playing: Combinatorial Search and Optimisation