Aerial robots are widely deployed, but highly cluttered environments such as dense forests remain inaccessible to drones and even more so to swarms of drones. In these scenarios, previously unknown surroundings and narrow corridors combined with requirements of swarm coordination can create challenges. To enable swarm navigation in the wild, we develop miniature but fully autonomous drones with a trajectory planner that can function in a timely and accurate manner based on limited information from onboard sensors. The planning problem satisfies various task requirements including flight efficiency, obstacle avoidance, and inter-robot collision avoidance, dynamical feasibility, swarm coordination, and so on, thus realizing an extensible planner. Furthermore, the proposed planner deforms trajectory shapes and adjusts time allocation synchronously based on spatial-temporal joint optimization. A high-quality trajectory thus can be obtained after exhaustively exploiting the solution space within only a few milliseconds, even in the most constrained environment. The planner is finally integrated into the developed palm-sized swarm platform with onboard perception, localization, and control. Benchmark comparisons validate the superior performance of the planner in trajectory quality and computing time. Various real-world field experiments demonstrate the extensibility of our system. Our approach evolves aerial robotics in three aspects: capability of cluttered environment navigation, extensibility to diverse task requirements, and coordination as a swarm without external facilities.

中文翻译：

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一群微型飞行机器人在野外

空中机器人被广泛部署，但高度杂乱的环境，如茂密的森林，仍然无法让无人机进入，对于成群的无人机来说更是如此。在这些情况下，以前未知的环境和狭窄的走廊以及群体协调的要求可能会带来挑战。为了在野外实现群体导航，我们开发了具有轨迹规划器的微型但完全自主的无人机，该无人机可以根据来自机载传感器的有限信息及时准确地运行。规划问题满足飞行效率、避障、机器人间避碰、动态可行性、群体协调等多种任务要求，实现了可扩展的规划器。此外，所提出的规划器基于时空联合优化同步变形轨迹形状并调整时间分配。因此，即使在最受限制的环境中，也可以在几毫秒内彻底利用解空间后获得高质量的轨迹。规划器最终集成到开发的手掌大小的群平台中，具有板载感知、定位和控制功能。基准比较验证了规划器在轨迹质量和计算时间方面的卓越性能。各种真实世界的现场实验证明了我们系统的可扩展性。我们的方法在三个方面发展了空中机器人技术：杂乱环境导航的能力、对不同任务要求的可扩展性以及在没有外部设施的情况下作为群的协调。