Many fish species gather by the thousands and swim in harmony with seemingly no effort. Large schools display a range of impressive collective behaviors, from simple shoaling to collective migration and from basic predator evasion to dynamic maneuvers such as bait balls and flash expansion. A wealth of experimental and theoretical work has shown that these complex three-dimensional (3D) behaviors can arise from visual observations of nearby neighbors, without explicit communication. By contrast, most underwater robot collectives rely on centralized, above-water, explicit communication and, as a result, exhibit limited coordination complexity. Here, we demonstrate 3D collective behaviors with a swarm of fish-inspired miniature underwater robots that use only implicit communication mediated through the production and sensing of blue light. We show that complex and dynamic 3D collective behaviors—synchrony, dispersion/aggregation, dynamic circle formation, and search-capture—can be achieved by sensing minimal, noisy impressions of neighbors, without any centralized intervention. Our results provide insights into the power of implicit coordination and are of interest for future underwater robots that display collective capabilities on par with fish schools for applications such as environmental monitoring and search in coral reefs and coastal environments.

许多鱼类成群结队地聚集在一起，似乎毫不费力地和谐游动。大型学校展示了一系列令人印象深刻的集体行为，从简单的浅滩到集体迁徙，从基本的捕食者逃避到诱饵球和闪光扩张等动态机动。大量的实验和理论工作表明，这些复杂的三维 (3D) 行为可以通过对附近邻居的视觉观察而产生，而无需进行明确的交流。相比之下，大多数水下机器人集体依赖于集中式、水上、显式通信，因此表现出有限的协调复杂性。在这里，我们展示了一群受鱼类启发的微型水下机器人的 3D 集体行为，这些机器人仅使用通过产生和感知蓝光进行中介的隐式通信。我们展示了复杂和动态的 3D 集体行为——同步、分散/聚合、动态圆圈形成和搜索捕获——可以通过感知邻居的最小、嘈杂印象来实现，而无需任何集中干预。我们的研究结果提供了对隐式协调能力的见解，并且对未来的水下机器人感兴趣，这些机器人显示出与鱼群相同的集体能力，用于环境监测和珊瑚礁和沿海环境搜索等应用。