Motion Planning for Unlabeled Discs with Optimality Guarantees

TL;DR

This paper presents a novel algorithm for path planning of unlabeled unit-disc robots in cluttered environments, guaranteeing near-optimal solutions with proven bounds and efficient implementation.

Contribution

It introduces the first algorithm with optimality guarantees for unlabeled disc robot path planning in complex environments.

Findings

Algorithm guarantees solution existence or reports failure.

Total path length is within OPT+4m of optimal.

Experimental results demonstrate efficiency and practicality.

Abstract

We study the problem of path planning for unlabeled (indistinguishable) unit-disc robots in a planar environment cluttered with polygonal obstacles. We introduce an algorithm which minimizes the total path length, i.e., the sum of lengths of the individual paths. Our algorithm is guaranteed to find a solution if one exists, or report that none exists otherwise. It runs in time $\tilde{O}(m^4+m^2n^2)$, where $m$ is the number of robots and $n$ is the total complexity of the workspace. Moreover, the total length of the returned solution is at most $\text{OPT}+4m$, where OPT is the optimal solution cost. To the best of our knowledge this is the first algorithm for the problem that has such guarantees. The algorithm has been implemented in an exact manner and we present experimental results that attest to its efficiency.