Communication-Constrained Multi-Robot Exploration with Intermittent Rendezvous

TL;DR

This paper proposes a novel approach for multi-robot exploration under communication constraints by modeling the task as a DEC-POMDP and planning rendezvous points via Job Shop Scheduling, improving efficiency over traditional relay methods.

Contribution

It introduces a joint exploration policy with rendezvous planning modeled as a JSSP, enabling effective coordination despite intermittent communication constraints.

Findings

Simulation shows improved exploration efficiency

Rendezvous planning reduces waiting times

Method outperforms relay-based communication strategies

Abstract

Communication constraints can significantly impact robots' ability to share information, coordinate their movements, and synchronize their actions, thus limiting coordination in Multi-Robot Exploration (MRE) applications. In this work, we address these challenges by modeling the MRE application as a DEC-POMDP and designing a joint policy that follows a rendezvous plan. This policy allows robots to explore unknown environments while intermittently sharing maps opportunistically or at rendezvous locations without being constrained by joint path optimizations. To generate the rendezvous plan, robots represent the MRE task as an instance of the Job Shop Scheduling Problem (JSSP) and minimize JSSP metrics. They aim to reduce waiting times and increase connectivity, which correlates to the DEC-POMDP rewards and time to complete the task. Our simulation results suggest that our method is more efficient than using relays or maintaining intermittent communication with a base station, being a suitable approach for Multi-Robot Exploration. We developed a proof-of-concept using the Robot Operating System (ROS) that is available at: https://github.com/multirobotplayground/ROS-Noetic-Multi-robot-Sandbox.