Emergent velocity agreement in robot networks

TL;DR

This paper introduces a novel self-stabilizing algorithm enabling a flock of oblivious, asynchronous robots to achieve velocity agreement and follow a leader in a plane, even after disruptions, without prior shared coordinates.

Contribution

The paper presents the first self-stabilizing flocking algorithm for oblivious, asynchronous robots that guarantees velocity agreement and pattern preservation under arbitrary initial conditions.

Findings

Algorithm ensures flocking with velocity agreement in asynchronous settings

System is self-healing, re-electing a new leader if the original leaves

Step complexity of the solution is O(n)

Abstract

In this paper we propose and prove correct a new self-stabilizing velocity agreement (flocking) algorithm for oblivious and asynchronous robot networks. Our algorithm allows a flock of uniform robots to follow a flock head emergent during the computation whatever its direction in plane. Robots are asynchronous, oblivious and do not share a common coordinate system. Our solution includes three modules architectured as follows: creation of a common coordinate system that also allows the emergence of a flock-head, setting up the flock pattern and moving the flock. The novelty of our approach steams in identifying the necessary conditions on the flock pattern placement and the velocity of the flock-head (rotation, translation or speed) that allow the flock to both follow the exact same head and to preserve the flock pattern. Additionally, our system is self-healing and self-stabilizing. In the event of the head leave (the leading robot disappears or is damaged and cannot be recognized by the other robots) the flock agrees on another head and follows the trajectory of the new head. Also, robots are oblivious (they do not recall the result of their previous computations) and we make no assumption on their initial position. The step complexity of our solution is O(n).