Video: Watch an eagle-like drone grab objects mid-flight

Lunch, anyone? (Image: Inaki Relanzon/naturepl.com)

AS IF being eyes in the sky weren’t enough, drones are now getting arms and legs, too. With their newfound limbs they are learning to grab objects in mid-flight or even change a light bulb.

Inspired by the way a bald eagle swoops down to seize a fish from the water with its claws, Justin Thomas and colleagues at the University of Pennsylvania in Philadelphia have developed a fast-acting, talon-like gripper for a small unmanned aerial vehicle (UAV).

When the team studied the eagle’s behaviour, they noticed that the bird employed a useful trick to buy more time to grab its prey. The eagle would sweep its legs and claws backwards as its talons closed on a fish, so there was no need to slow down.


The team have mimicked the eagle’s strategy by attaching a 3D-printed, three-fingered claw to a 10-centimetre-long motorised leg. With the appendage fixed below its centre of mass, the drone can snatch a stationary object as it flies by.

Meanwhile, at Drexel University, also in Philadelphia, Christopher Korpela is developing flight stability software for rotor-driven drones with arms. This will allow UAVs with limbs to carry a burden without the added mass making them fall out of the air.

To get around the problem, Korpela and colleagues are designing the software so the drone can reposition the load in flight to achieve better control – something birds do naturally. “We are trying to compensate for the reactions the vehicle undergoes when it tries to open a door, for example,” he says.

His aim is to allow a quad-rotor UAV to help out with tasks like bridge repair, pruning trees, fetching medication, using hand tools or even changing a light bulb. “A UAV with arms could perform the same tasks as a ground robot, but with a three-dimensional workspace,” Korpela told New Scientist.

“Drones with limbs will be able to help out with tasks like bridge repair, pruning trees and using hand tools”

He will present the software in May at the International Conference on Robotics and Automation in Karlsruhe, Germany.

It will be a while before flying robots with arms and legs find their way into wider use, though. “We still have a long way to go to develop aircraft capable of safely interacting with people or the environment,” says Korpela.

This article appeared in print under the headline “Drone makes like an eagle to snatch quarry on the fly”