On Formation Control Strategies in a Failure-Prevention Scenario for Multi-UAV Payload Transportation

This study considers a system composed of multiple Unmanned Aerial Vehicles (UAVs), carrying a payload by flexible cables. A formation control problem is addressed in the course of a path-following procedure. In the context of a scenario where one UAV could fail during the flight and is automatically detached from the system, the optimal formation to be kept for the whole mission is found, which would minimize the maximum path the remaining UAVs should travel to change the formation if any of the UAVs would fail. The focus is on a system with three UAVs and the transition to a formation of two UAVs is studied after possible failures. The evolution of the system is described by a set of dynamic equations; a considered software architecture is provided, and software-in-the-loop tests are performed to validate the proposed algorithms. Results compare the performances of the proposed formation against a static configuration in a failure scenario of one UAV during the path-following, highlighting the benefits of the first when the failure happens in critical points during the flight. Video: https://youtu.be/BuLZwTGbV5M.