Limited battery life has always been one of the main challenges for using drones in applications that require long flight times, such as infrastructure monitoring or search and rescue operations. What if the drone could recharge itself in flight, using the energy of high voltage electrical cables? This is the brilliant idea that pushed a team of researchers from the University of Southern Denmark to develop an innovative system that allows a drone to perch on electric cables and "suck" the energy needed to recharge its batteries, just like a vampire thirsty for… electricity.
Vampire drone, the origins
The idea of using power lines to charge drones was born in 2017, when Emad Ebeid, professor at the University of Southern Denmark (SDU), was exploring the applications of drones and identified power line inspection as an area of interest. According to the drone's developers, Ebeid noted that the current inspection process, which relied on helicopters and ground personnel, was expensive and inefficient. He therefore thought of drones as a natural alternative to this very expensive maintenance effort.
The main problem, as mentioned, was represented by the limited autonomy of the drones (a maximum of 40 minutes of flight for the most advanced models and only 30 minutes for the majority of industrial drones). To ensure complete autonomy, the drones needed a charging system that did not require human intervention. The solution turned out to be right before Ebeid's eyes: the power lines themselves. The vampire drone was born: only he didn't know it yet.
Suck the energy without frying the drone
Designing a system that would allow the drone to perch and suck electricity from a power line proved to be a daunting challenge. The researchers faced several problems, starting with how to make the drone interact with the cable. After extensive testing, they programmed the drone to approach the power line from below, reducing the risk of collision. In no time, they had to find a way to securely attach the drone to the cable. The solution was to equip the drone with an insulated clamp that attaches to the power line without conducting electricity to the aircraft. This docking mechanism requires no motors to operate, simplifying the design and reducing possible failure points.
The last obstacle to overcome it was like using the electricity of line to charge the drone without damage it. The solution was inductive coupling: taking advantage of the magnetic field created around high voltage cables, the drone uses a metal coil to induce a current and recharge its battery, similar to wireless smartphone chargers.
Successful tests and future prospects
After seven years of development, the team finally managed to get the system working. During tests conducted at HCA Airport in Denmark, the drone performed five charging sessions without any human intervention flying continuously for two hours, a huge step up from the typical 30 minutes of battery life.
Engineers are now working to optimize the system and make it resistant to adverse weather conditions. Before we see a vampire drone flying in our skies, it will be necessary to resolve even more banal questions. To say: who pays for the energy "sucked" by the power lines? Once all the details are worked out, the potential of this technology is enormous. With around 25 million kilometers of power lines around the world, drones could recharge and create 24/24 monitoring networks, revolutionizing entire industrial sectors.
From emergency relief to optimizing operations, through to saving money and lives, the applications and benefits that can arise from this technology are, as the inventors say, “as vast as the global electricity grid itself”. Not bad, Count Drone.
