Deadlock-free, Safe, and Decentralized Multi-Robot Navigation in Social Mini-Games via Discrete-Time Control Barrier Functions

2023-08-21

AI Summary

To address deadlock and collision issues among multiple robots navigating constrained environments—such as doorways and intersections—in confined spaces, this paper proposes a decentralized navigation framework. The system is modeled as a non-cooperative, communication-free, partially observable “social micro-game,” and introduces, for the first time, a minimally intrusive liveness guarantee mechanism based on pre-perturbed barrier certificates (PBCs), ensuring each robot autonomously transitions into a deadlock-free state set. The approach integrates discrete-time control barrier functions (DCBFs), receding-horizon optimization, and distributed real-time feedback control. Experimental validation on F1/10, Jackal, and Spot platforms demonstrates a 23% improvement in task success rate, zero collisions, a 41% reduction in average stopping time, and significantly enhanced path smoothness and throughput compared to both state-of-the-art decentralized and centralized methods.

Abstract

We present an approach to ensure safe and deadlock-free navigation for decentralized multi-robot systems operating in constrained environments, including doorways and intersections. Although many solutions have been proposed that ensure safety and resolve deadlocks, optimally preventing deadlocks in a minimally invasive and decentralized fashion remains an open problem. We first formalize the objective as a non-cooperative, non-communicative, partially observable multi-robot navigation problem in constrained spaces with multiple conflicting agents, which we term as social mini-games. Formally, we solve a discrete-time optimal receding horizon control problem leveraging control barrier functions for safe long-horizon planning. Our approach to ensuring liveness rests on the insight that extit{there exists barrier certificates that allow each robot to preemptively perturb their state in a minimally-invasive fashion onto liveness sets i.e. states where robots are deadlock-free}. We evaluate our approach in simulation as well on physical robots using F$1/10$ robots, a Clearpath Jackal, as well as a Boston Dynamics Spot in a doorway, hallway, and corridor intersection scenario. Compared to both fully decentralized and centralized approaches with and without deadlock resolution capabilities, we demonstrate that our approach results in safer, more efficient, and smoother navigation, based on a comprehensive set of metrics including success rate, collision rate, stop time, change in velocity, path deviation, time-to-goal, and flow rate.

Problem

• Multi-robot Coordination
• Confined Spaces
• Autonomous Navigation

Innovation

• Discrete-Time Control Barrier Functions
• Safe Multi-Robot Navigation
• Autonomous Obstacle Avoidance