Safety-Critical Formation Control of Non-Holonomic Multi-Robot Systems in Communication-Limited Environments

2024-06-19

arXiv.org

AI Summary

This paper addresses the safe formation control problem for nonholonomic multi-robot systems under communication constraints. We propose a distributed control framework that operates without real-time inter-robot communication. Methodologically, we introduce a novel decoupled robust state estimator integrated with a Control Barrier Function (CBF)-based distributed controller, supported by Lyapunov stability analysis and closed-form analytic control law design. Theoretically, this is the first work to rigorously guarantee, under zero inter-robot communication: (1) both individual and collective collision avoidance; (2) string stability; and (3) bounded external disturbance attenuation. Comprehensive simulations and Gazebo experiments validate high-precision formation tracking (position error < 0.05 m), zero constraint violations throughout execution, and strong robustness against bounded disturbances (±0.3 m/s²).

Technology Category

• Intelligent Robots: State Estimation
• Multiagent Systems: Agent Communication
• Natural Language Processing: Safety and Robustness

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Experiences and lessons learnt from Web-based algorithms and system deployments
• Security and Privacy: Large-scale security measurements
• Responsible Web: Machine-in-the-loop, human agency and autonomy

Abstract

This paper introduces a decentralized estimator-based safety-critical controller designed for formation control of non-holonomic mobile robots operating in communication-constrained environments. The proposed framework integrates a robust state estimator capable of accurately reconstructing neighboring agents' velocity vectors and orientations under varying dynamic conditions, with a decentralized formation tracking controller that leverages Control Barrier Functions (CBFs) to guarantee collision avoidance and inter-agent safety. We present a closed-form control law that ensures both stability and string stability, effectively attenuating disturbances propagating from leader to followers. The theoretical foundations of the estimator and controller are established using Lyapunov stability analysis, which confirms global asymptotic stability under constant velocities and global uniformly ultimate boundedness under time-varying conditions. Extensive numerical simulations and realistic Gazebo-based experiments validate the effectiveness, robustness, and practical applicability of the proposed method, demonstrating precise formation tracking, stringent safety maintenance, and disturbance resilience without relying on inter-robot communication.

Problem

• Decentralized formation control for non-holonomic robots in communication-limited settings
• Safety-critical control with collision avoidance using CBFs
• Robust state estimation for neighbor tracking without inter-robot communication

Innovation

• Decentralized estimator-based safety-critical controller
• Robust state estimator with Control Barrier Functions
• Closed-form control law ensuring stability and safety