Dynamic Median Consensus for Marine Multi-Robot Systems Using Acoustic Communication

TL;DR

This paper introduces a dynamic median consensus protocol for underwater multi-robot systems using acoustic communication, enabling robust environmental monitoring by accurately aggregating sensor data despite changing network topologies.

Contribution

It presents the first implementation and validation of a median consensus protocol for underwater robots, with theoretical stability proof and experimental demonstration.

Findings

Protocol converges to median of measurements

Robustness to outliers demonstrated

Successful real-world underwater deployment

Abstract

In this paper, we present a dynamic median consensus protocol for multi-agent systems using acoustic communication. The motivating target scenario is a multi-agent system consisting of underwater robots acting as intelligent sensors, applied to continuous monitoring of the state of a marine environment. The proposed protocol allows each agent to track the median value of individual measurements of all agents through local communication with neighbouring agents. Median is chosen as a measure robust to outliers, as opposed to average value, which is usually used. In contrast to the existing consensus protocols, the proposed protocol is dynamic, uses a switching communication topology and converges to median of measured signals. Stability and correctness of the protocol are theoretically proven. The protocol is tested in simulation, and accuracy and influence of protocol parameters on the system output are analyzed. The protocol is implemented and validated by a set of experiments on an underwater group of robots comprising of aMussel units. This experimental setup is one of the first deployments of any type of consensus protocol for an underwater setting. Both simulation and experimental results confirm the correctness of the presented approach.