A Conflict Avoidance Table for Continuous Conflict-Based Search (Extended Abstract)

Abstract

Conflict-Based Search is a state-of-the-art algorithm solving the Multi-Agent Path Finding problem. Given multiple agents with start and goal locations, the problem is to find a set of collision-free paths of minimal cost. Continuous Conflict-Based Search is a recent adaptation of this algorithm for continuous time and agents with physical shapes. However, an important ingredient has not been adapted to this continuous version: the Conflict Avoidance Table. It is used as a tie-breaking strategy in single-agent search phases to favor paths causing fewer conflicts with the other agents. This paper explains how the R-Tree can be used as a Conflict Avoidance Table for Continuous Conflict-Based Search. The experiments show that using the Conflict Avoidance Table can reduce the number of nodes expanded by the algorithm by a large margin. As a result, the solving time is improved proportionally and especially when using the implementation based on R-Trees as opposed to a naive implementation.