Fast Swarming of UAVs in GNSS-Denied Feature-Poor Environments Without Explicit Communication

A decentralized swarm approach for the fast cooperative flight of Unmanned Aerial Vehicles (UAVs) in feature-poor environments without any external localization and communication is introduced in this letter. A novel model of a UAV neighborhood is proposed to achieve robust onboard mutual perception and flocking state feedback control, which is designed to decrease the inter-agent oscillations common in standard reactive swarm models employed in fast collective motion. The novel swarming methodology is supplemented with an enhanced Multi-Robot State Estimation (MRSE) strategy to increase the reliability of the purely onboard localization, which may be unreliable in real environments. Although MRSE and the neighborhood model may rely on information exchange between agents, we introduce a communication-less version of the swarming framework based on estimating communicated states to decrease dependence on the often unreliable communication networks of large swarms. The proposed solution has been verified by a set of complex real-world experiments to demonstrate its overall capability in different conditions, including a UAV interception-motivated task with a group velocity reaching the physical limits of the individual hardware platforms.

I. Introduction

Aerial robotic swarms could revolutionize various domains due to enhanced efficiency, robustness, fault tolerance, and cooperative problem-solving abilities. These abilities are currently difficult to achieve due to the apparent complexity of the overall solution and the demanding system transfer from laboratories and simulations to the real world. The available solutions [1] are limited mainly by the physical constraints and high demands on impractical sensory equipment, as well as the communication load. To effectively deploy a swarm of UAVs (Fig. 1) in tasks, such as exploration and monitoring [2], [3] and search and rescue operations [4], [5], it is necessary to mitigate the limitations mentioned.