Safety-boundary-aware time-varying formation control for multi-agent systems in unknown corridors

Safe traversal of multi-agent formations in constrained environments is essential for many cooperative robotic applications, yet existing methods often rely on accurate prior maps, which limit their applicability in unknown corridors. To overcome this challenge, this paper studies the safe traversal of multi-agent systems through unknown corridors using time-varying formations, where agents possess only coarse prior knowledge of the corridor and must rely on online perception to progressively refine environmental information. To ensure safety during traversal under such limited information, an online safety-boundary construction method is proposed to derive an inner safety envelope with an explicit margin that is theoretically guaranteed to lie within the true boundary. Unlike approaches that depend on local obstacle avoidance, we compute the time-varying formation parameters under the safety-boundary constraints to generate reference trajectories for all agents. Accurate tracking of the generated reference trajectories is achieved by designing a trajectory-tracking control law. Simulation results show that, while preserving the prescribed formation geometry with high accuracy, the proposed method efficiently utilizes the available corridor space, achieving an average corridor utilization rate of 96.2%.