Contingency Model-based Control (CMC) for Communicationless Cooperative Collision Avoidance in Robot Swarms

TL;DR

This paper introduces a communicationless decentralized control method for robot swarms, ensuring collision avoidance through predefined rules and contingency trajectories, thus overcoming communication failures and attacks.

Contribution

It proposes Contingency Model-based Control (CMC), a novel decentralized approach that guarantees collision avoidance without relying on communication among agents.

Findings

CMC guarantees recursive feasibility and collision avoidance.

The approach allows dynamic entry of new robots into the swarm.

Numerical examples demonstrate smooth operation in constrained environments.

Abstract

Cooperative collision avoidance between robots, or `agents,' in swarm operations remains an open challenge. Assuming a decentralized architecture, each agent is responsible for making its own decisions and choosing its control actions. Most existing approaches rely on a (wireless) communication network between (some of) the agents. In reality, however, communication is brittle. It may be affected by latency, further delays and packet losses, and transmission faults. Moreover, it is subject to adversarial attacks, such as jamming or spoofing. This paper proposes Contingency Model-based Control (CMC), a decentralized cooperative approach that does not rely on communication. Instead, the control algorithm is based on consensual rules that are designed for all agents offline, similar to traffic rules. For CMC, this includes the definition of a contingency trajectory for each robot, and perpendicular bisecting planes as collision avoidance constraints. The setup permits a full guarantee of recursive feasibility and collision avoidance between all swarm members in closed-loop operation. CMC naturally satisfies the plug & play paradigm, i.e., new robots may enter the swarm dynamically. The effectiveness of the CMC regime is demonstrated in two numerical examples, showing that the collision avoidance guarantee is intact and the robot swarm operates smoothly in a constrained environment.