PC-Explorer: Decentralized Multi-UAV Exploration in Bandwidth-Limited Environments

Achieving efficient cooperative exploration with multiple Unmanned Aerial Vehicles (UAV) is challenging due to the conflict between the requirement for map sharing among UAVs and the limited onboard communication resources. In this letter, we propose PC-Explorer, a decentralized cooperative exploration planner designed for bandwidth-limited environments. To enable efficient data transmission, the map information is abstracted into two novel structures: the spatial information of globally known areas is abstracted into pseudo-convex polytope (PC-polytope), while the information of unknown areas is represented by frontier-cluster cuboid (FC-cuboid). These data structures are further encoded into a lightweight exploration message package (EMP) for transmission among UAVs, which helps to construct an exploration information map on each UAV independently. Supported by the information map, an efficient cooperative exploration planner is developed to generate exploration trajectory for each UAV. The performance of PC-Explorer is compared with state-of-the-art methods in simulation, and its effectiveness is further validated in a real-world experiment conducted in a forest of 5909.89 $m^{2}$. The video of simulation and real-world experiment can be found at https://youtu.be/bef1q-MDPSk.