The US Army is taking wireless recharging to new heights, by using lasers to power聽small drones in mid-air.
Small flying vehicles with several rotating blades, known as multicopters or drones, have proven valuable to the military for intelligence gathering. But they are incredibly power-hungry, meaning their flying time is limited to half an hour or less.
Now the US Army鈥檚 Communications-Electronics Research, Development and Engineering Center based in Maryland are developing a power beaming system with a combination of modern lasers and efficient photovoltaic cells.
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The aim is to provide power from five hundred metres away 鈥� enough to keep a drone patrolling indefinitely above a base or fly over a convoy for its entire route. The system works by firing laser light at the drone鈥檚 photovoltaic cell, which then converts the light into electricity.
鈥淭he major challenge we see is thermal management,鈥� says William Rowley, who works on the project. Energy not converted to electricity becomes heat, so there is a risk of melting or burning the drone. They plan to overcome this problem by developing accurate beam control and ensuring the excess heat can dissipate.
The plan looks technically feasible, says David Anderson at the University of Glasgow. Though proving its safety is another matter, given the potential risks from the high-energy beam. Remote power systems have been laboratory toys since the 60s, but a practical working prototype has not previously been developed. The project aims to demonstrate a working ground-to-ground system in early 2019 with ground-to-air following in 2020
鈥淭he challenge is how you can convince the regulatory authorities that it is safe,鈥� says Anderson. 鈥淪pecifically, you have to persuade them that the laser will not miss the drone energy collector panel when charging.鈥�
