Reactive Swarm Control for Unpredictable Environments
Date:
Control barrier functions (CBFs) are widely used in multi-robot systems to augment control commands to enforce system safety. However, this safety guarantee can come at the cost of slower robot navigation. Therefore, in this work we introduce a framework for using time-invariant CBFs to form a time-varying CBF that guarantees safety while accelerating multi-robot navigation tasks. We first show that a time-varying convex combination of time-invariant CBFs forms a valid time-varying CBF, which renders the time-dependent safe set forward invariant. We also prove that the safe set is uniformly asymptotically stable. Then we introduce an algorithm that alters CBF shapes in real time to accelerate navigation tasks. The performance of the proposed algorithm is validated in hardware experiments in congested multi-robot environments, and it achieves up to a 43% reduction in the time required to complete navigation tasks compared to a baseline time-invariant CBF implementation.