Drones

Video: Crafty quadcopter sits on power lines to recharge

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The drone is intended to draw power from lines that it's already been tasked with inspecting
University of Southern Denmark
A closer look at the drone, showing its cable guide (white) and gripper (yellow/blue)
University of Southern Denmark
The drone is intended to draw power from lines that it's already been tasked with inspecting
University of Southern Denmark

Battery life wouldn't be an issue for drones if they could just recharge on power lines as needed. That's exactly what an experimental new quadcopter can now do, allowing it to stay aloft pretty much indefinitely.

Developed by scientists from the University of Southern Denmark, the charging technology could be utilized by drones carrying out a wide variety of tasks. That said, it's intended first and foremost for use by autonomous drones performing power line inspections. After all, those copters are already going to be within easy reach of the lines at all times.

Viet Duong Hoang and colleagues started with a commercial Tarot 650 Sport carbon fiber drone frame, then added an electric quadcopter propulsion system, a 7,000-mAh lithium-polymer battery, and electronic components such as a Raspberry Pi 4 B microcomputer, a Pixhawk V6X autopilot module, plus a millimeter-wave radar unit and an RGB video camera.

Importantly, they also installed a passively actuated power-line-gripper on top of the drone. This device sits within a cable guide consisting of two widely spread inward-sloping arms.

A closer look at the drone, showing its cable guide (white) and gripper (yellow/blue)
University of Southern Denmark

When the drone's onboard software detects that its battery is getting low, the aircraft uses its camera and radar to spot the closest power line. The aircraft then flies straight up toward that line from underneath.

Upon reaching the power line, the drone's cable guide directs the line into the gripper. As the line goes in, it pushes down on two elastomer ribbons spanning the open space between the gripper's two rubber sides. This action causes those sides to quickly close together overtop of the power line – no electricity required.

That said, once the line has been gripped, a magnetic control circuit kicks in to power the gripper, keeping it firmly closed around the line as the drone hangs beneath. A top-located inductive charger on the drone then starts drawing current from the power line. Once the aircraft's battery is fully charged, the gripper opens and the drone can resume its line-inspecting duties.

It should be noted that only a small amount of upward thrust by the drone is required to initially trip the gripper. Additionally, if the voltage of the power line is sufficient, it serves as the power source for the control circuit – otherwise, the drone's battery is used.

In field tests performed on power lines at Denmark's HCA Airport, the 4.3-kg (9.5-lb) demonstrator drone was able to operate for over two hours, recharging its battery five times between line-inspection sessions. The scientists are now working on boosting the system's robustness, and hope to test it in both more remote locations and adverse weather conditions.

You can see the drone in power-line-gripping action, in the video below. A paper on the research is being presented at The 2024 IEEE International Conference on Robotics and Automation.

And for another take on power-line-inspecting drone-like things, check out the LineRanger robot, which crawls along lines instead of flying overtop of them.

Source: University of Southern Denmark

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9 comments
BT
Yes, let’s just leave live powerlines for birds and squirrels..
Bad idea is bad.
BT
Birds. Squirrels. Active powerlines. Bad idea.
Wombat56
OK, so how does it actually harvest the energy to recharge, sitting on just one wire, as it does?

Capacitive coupling? Magnetic fields?
DavidB
“…stay aloft pretty much indefinitely”?
LOL

Only a marketer could try to call being tethered to a power line for recharging the same as staying aloft in any useful sense of the term.

That’d be the same marketing boffin who thinks “over two hours [minus the time spent] recharging its battery five times” is “pretty much indefinitely."

These people clearly think we’re stupid, as well as having absolutely no sense of shame.
christopher
@Wombat56 the ground (or other wire), even though it's a long way, is still close enough that you can get power out of the single wire. You can try this yourself even - grab one end of a long fluro tube, and point the other at an HV powerline: it lights up, even though it's a dozen meters above you.

This is basically the same as an "SWER" (Single-Wire-Earth-Return) circuit that many farmers use - except the "earth return" is the air below the drone going down to the ground (or the air between the drone and the other line, depending on what kind of cable they dangle under).
froggywood
@Wombat56 regarding how the charging takes place - an annotated picture of the drone at about 0:25 in the video show a "current transformer" and states that the system uses "inductive coupling" A typical power line might have several hundreds of amperes of current running when live so this is a sound way of getting enough juice for charging.
pmshah
aren't these powerlines carrying power at between 75k and 230k volts? I have watched videos of humans servicing these lines. It was not only scary but mind boggling. Also the kind of money they make runs into hundreds of thousands of dollars. Wonder what level of capacitive surge would be involved when applying he hook.
Dosmastr
I think in most places this would qualify as theft.
bwana4swahili
Birds recharge this way all the time. A drone has finally caught on!