Charging Drones with Lasers So They Can Fly Forever

When it comes to using drones for commercial applications, battery life is one of the biggest limiting factors.

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Extending battery life has proved a tough challenge, and one that the drone industry has been laboring away at for years.

All this work has produced steady progress, with battery life steadily increasing. But the gains in flight time for drones that fly using your standard LiPo batteries have been relatively small despite all the work put into extending them.

Some less common approaches to powering drones have been tested, and seem promising. One is using hydrogen fuel cells, and tests have also been made with powering drones using gasoline (though these don’t seem to have gone anywhere).

Of course, you can also use a tether to send power up to the drone, allowing it to stay aloft as long as you want—but this means the drone has to remain stationary, since it’s leashed to the ground by the tether.

But there may be a way to power drones from a removed power source without having to tether them to ground.

That’s right—we’re talking about powering drones with lasers.

Credit: Northwestern Polytechnical University

New Breakthroughs for Laser-Powered Drones

The idea of using lasers as a power source for drones has been around for at least a decade.

But new research conducted by scientists at the Northwestern Polytechnical University (NPU) in China has been making the news lately, showing progress in work toward making this technology viable.

The team of researchers at NPU have equipped a drone with a module that converts light energy into electricity, allowing it to capture power from a high-energy laser beam so it can stay in flight indefinitely.

The researchers have dubbed these UAVs optics-driven drones (ODDs).

Credit: Northwestern Polytechnical University

Of course, for this laser-powering method to work the laser needs to be able to automatically track the drone.

For this reason, the researchers have made the laser adaptive and given it the ability to track its target—the photoelectric conversion module on the bottom of the drone—using an “intelligent visual tracking algorithm.”

According to NPU researchers, the algorithm has proven effective in a variety of environments, as well as differing light and weather conditions.

The lasers used to power the drone also have an adaptive technology that allows them to shape their beams autonomously, adjusting intensity as needed based on the distance the drone is from the power source and in instances where an object is detected between the laser beam and the drone.

The laser-power drone technology was recently tested on a small quadcopter. Tests were conducted outside at night and inside with both the lights on and off.

In the tests, the drone reaches a height of just about 33 feet in the air (see below for images from the tests).

Credit: Northwestern Polytechnical University

So far the NPU system has proven to be pretty inefficient, losing about 50% of the energy transmitted from the laser.

But it works.

And that may be all that matters right now, given that electricity is fairly inexpensive and that the approach allows the drone to can stay in the air indefinitely.

Other Laser-Charging Drone Projects

Here’s a quick rundown of other noteworthy efforts to charge drones with lasers.

PowerLight

In 2012, U.S.-based PowerLight (formerly known as LaserMotive), demonstrated its wireless drone charging system by keeping a large drone in the air for 48 hours in a wind tunnel.

The system was also used to power a Lockheed Martin Stalker drone outdoors at a range of 1,970 feet in the air.

Today PowerLight says it’s working on long-range, lightweight wireless laser power transmission system. Watch the video below to learn more.

DARPA’s Drone Laser Project

In 2018, DARPA (Defense Advanced Research Projects Agency) announced a program called the Stand-off Ubiquitous Power/Energy Replenishment—Power Beaming Demo (SUPER PBD).

The goal of the program was to test technology that would charge aircraft while in flight using laser beams.

In DARPA’s approach, the aircraft has solar panels in its wings and batteries in its fuselage. At first the batteries provide power to the aircraft, but as they run down a laser beam is pointed at the craft’s solar panels, allowing it recharge and stay in flight.

DARPA selected a UAS called Silent Falcon made by a company of the same name for its laser tests.

Credit: Silent Falcon

LakeDiamond

In 2018, a startup called LakeDiamond made news for its idea to use lab-grown diamonds to recharge drones while in flight.

The diamonds allow laser beams to maintain strength over a long distance, letting them recharge photovoltaic cells on the surface of the drone. In LakeDiamond’s laser, the light produced by a diode is directed at a booster composed of reflective material, an optical component, and a small metal plate to absorb the heat.

Credit: LakeDiamond

The Benefits of Charging Drones with Lasers

So why would you want to charge drones with lasers?

The obvious benefit is that you would no longer have to worry about battery life. Using lasers, you could hypothetically have a drone that could fly for as long as you wanted.

But there are specific use cases that would benefit from having a drone that can fly for a very long time—maybe even forever.

Here they are:

• Disaster relief. During time-consuming emergency missions, like searching for victims after a flash flood or earthquake, the ability to have a drone remain in the air for long periods of time could be extremely helpful.
• Traffic control. Traffic never stops, and continuously flying drones could be used to monitor traffic and help improve safety on the roads.
• Security patrols. Security concerns are in place every hour of the day, a fact that supports the idea of having a constant “eye in the sky” to monitor the security of a building or perimeter.
• Flying satellites. Laser-powered drones could be used for higher altitude drone operations, in which drones basically act like small low-altitude satellites.

The last one sounds a little unlikely, but it does reveal the places our imagination can take us when a drone is no longer limited by how long it can stay in the air.

Who knows—maybe we’ll see laser-powered drones rolled out within our lifetime. Results from the research being conducted today certainly makes it seem like a strong possibility.