Falcon drone

The Hawk-inspired robot with posable wings is an agile long-haul aviator

By Chris Stokel-Walker

This hawk-like drone is an agile and efficient flyer

2020 EPFL / Alain Herzog

A robot with wings that move like a hawk can fly more stable and nimble than other flying robots – and it uses less power and increases flight time.

Enrico Ajanic from the Swiss Federal Institute of Technology in Lausanne and his colleagues borrowed a 284-gram drone with a maximum wingspan of 1.05 meters from the biology of the northern goshawk (Accipiter gentilis). The vehicle contains 27 spring-like panels – nine on each wing and another nine on the stern – so it moves through the air like a hawk.

The goal was to develop a drone that could fly great distances through cities, but maneuver around buildings and objects that it is likely to encounter. "Multicopter drones can hover and move well, but they cannot fly long distances," says Ajanic. "Winged drones can fly long distances, but they are not very agile."


Motors allow the wings of the drone to be folded in or out and the tail to be contracted or fanned out, thereby mimicking the flight behavior of a bird. When the wings and tail are fully spread, the robot gains height. When the top speed is reached, the feather-like plates can be used more aerodynamically like a bird.

The tail also moves up and down and from side to side, allowing the robot to change its height quickly. Each wing can also be retracted or extended independently, if necessary, to increase or decrease drag. By plugging in the wings and tail at an optimal speed of 9.6 meters per second, the drone uses 55.4 percent less energy than would be required to travel at this speed with the wing and tail fully open.

"The transforming wing and tail structures of this design are revealing and novel," says Jonathan Aitken of the University of Sheffield, UK. He is impressed with the ability to quickly change maneuverability. "It offers the potential for unconventional flight maneuvers, such as slow but controlled flight at high angles of attack."

In the future, Ajanic would like to add artificial intelligence to be able to fly the drone without human intervention. "We want to make the drone more autonomous," he says.

Journal reference: Science Robotics, DOI: 10.1126 / scirobotics.abc2897

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