Drone autonomous operations near power lines are growing steadily and require innovative techniques to keep them on air. This paper presents a novel electromechanical recharging station that can be mounted on energized AC power line to charge the drone battery wirelessly without a need to modify the electrical infrastructure. The work shows a thorough analysis of the electrical and mechanical core components to build a flexible, lightweight and efficient recharging station that can be attached to a robotic arm. The work also discusses the recharging station design and its special robot end effector that mechanically couples the station with an aerial manipulator. Finally, the recharging station has been tested in the lab and in a real power line setup to validate its design and efficiency. The total achieved mass is 2300 grams with a harvesting efficiency of 77% at 250 A primary current.INDEX TERMS Recharging station, energy harvesting, drone, end effector, power line, unmanned aerial vehicle, aerial robotic manipulation.

Recent research has pushed the applications of UAVs into domains such as infrastructure inspection and interaction. For UAVs to be able to safely and efficiently perform autonomous operations near the target infrastructure, they need to be aware of their surroundings while exposing navigation API to the application software. For powerline inspection UAVs, this yields a requirement for knowledge of the powerline cable positions and a set of actions facilitating specific flight operations in this environment. This work presents a hardware/software system solving these requirements. A framework is shown which allows application software to autonomously fly the UAV to any of the perceived cables, to fly the UAV along a cable, and to land on and takeoff from a cable. The system relies on an abstract representation of the identified and tracked cables, while solving the flight maneuvers using an MPC based trajectory planning routine. The system is tested in a real powerline environment featuring four cables stretched between two pylons. A GUI application is developed for triggering the actions remotely from a ground control station while providing a visual representation of the perceived cables and planned trajectories.