Remote refuelling drone

The performance and battery life of drones have long been a key limiting factor in their use for industrial purposes. The goal, of course, would be to get a tiny but smart aircraft to work in the air for as long as possible with a single take-off.

The necessary trade-offs between maximum take-off weight and the longest achievable flight time are a problem that many countries around the world are working on. Researchers at the University of Southern Denmark have been working on the issue for years and have come up with a very specific answer: a drone that can ‘harness’ and recharge itself on power lines carrying electricity.

This could be facilitated by an aircraft capable of ‘refuelling’ and taking off again on the transmission line under inspection.

The Danish drone researchers have fitted a special mechanical coupling system to a Tarot 650 Sport quadcopter (i.e. a drone with four electric motors and propellers). If the drone’s on-board systems detect that the battery is running low, the device uses its camera and short-range millimetre-wave radar system to find the nearest power line.

The drone then flies over the transmission line, slowly descends onto it and guides the overhead cable into the connector system using a pair of inward-folding arms. An inductive charger feeds current into the battery, transforming it to the correct voltage, and once fully charged, the drone takes off on its own and continues its mission. The researchers first demonstrated their concept in 2022, and now the experimental aircraft is flying with an improved connector system. This will allow them to demonstrate real-world applications of the technology in ‘live’ conditions.

In a paper to be presented at the IEEE International Conference on Robotics and Automation (ICRA2024 ) in Yokohama in mid-May, the research team claims that “to the best of our knowledge, this is the first system in the world that can sustain its operation through multiple control/charging cycles using energy from power lines in a real outdoor environment”.

In the most successful and longest-running test to date, the drone stayed airborne for more than two hours while the controller recharged its batteries five times using the power lines. But experts say there is a serious question over the safe operation of the system: if a drone refuelling a power line in a difficult-to-reach section, such as a high mountain area or in the middle of a dense forest, it could mean a longer power cut for even larger regions.

Source: 2024.ieee-icra.org