In this letter, we present a distributed algorithm for flocking in complex environments that operates at constant altitude, without explicit communication, no a priori information about the environment, and by using only on-board sensing and computation capabilities. We provide sufficient conditions to guarantee collision avoidance with obstacles and other robots without exceeding a desired maximum distance from a predefined set of neighbors (flocking or proximity maintenance constraint) during the mission. The proposed approach allows to operate in crowded scenarios and to explicitly deal with tracking errors and on-board sensing errors. The algorithm was verified through simulations with varying number of UAVs and also through numerous real-world experiments in a dense forest involving up to four UAVs.

翻译：本文提出一种适用于复杂环境的分布式集群飞行算法，该算法可在恒定高度运行，无需显式通信，无需环境先验信息，仅依赖机载传感与计算能力。我们给出了充分条件，以保证任务期间在不超过预设邻域集（集群飞行或邻近保持约束）最大距离的前提下，实现与障碍物及其他机器人的碰撞规避。所提方法能够在拥挤场景中运行，并显式处理跟踪误差与机载传感误差。通过不同数量无人机的仿真实验，以及在茂密森林中最多四架无人机的多次实地实验，验证了该算法的有效性。