Drones Will Fly As Gracefully As Birds

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Photo: Linda Cicero, Stanford University

Birds have been around for around 150 million years. Flying drones are much newer. So it’s only natural that the people designing the latter would take cues from the former in their quest to make airborne robots that can safely and effectively navigate the skies. Thanks to birds, there are now drones that can hit an object mid-flight and keep on going, drones that fly in birdlike formations, and drones that dance through the sky so convincingly, they’ve got real birds buying it.

The latest example comes from Stanford, where a team of researchers studied bird and bat wings to build a drone that could withstand collisions. The key to their success was a flexible set of wings, complete with a wrist and shoulder joint, which can absorb mid-air impacts and spring back into position passively. Researchers say this is a step toward being able to fly drones in cluttered environments, like forests, where rigid-wing drones might be knocked to the ground with no ability to recover. (This skill would probably come in handy in cities, too.)

“Real birds are able to precisely control their wind motions, and this enables them to do very impressive aerobatics,” says University of Maryland robotics professor SK Gupta in this video. His team’s Robo Raven has digitally controlled wings that move independent of one another, allowing the drone to perform dives and backflips in the air. The drone is so birdlike that a hawk attacked it mid-flight.

The lessons birds can teach drones don’t end with wing structure, though. A team of Hungarian researchers looked at how birds flock together in order to design a group of drones that fly in formation. Along with modifying a fleet of quadcopters and adding GPS, small processors, and radios for communication, the researchers devised “flocking algorithms.” The drones were then able to fly together without the help of a central computer. Instead, a set of rules allowed them to communicate among themselves in order to find their way through tight spaces and restrictive paths. Physicist Tamas Vicsek, who led on the design team, compared them to “gregarious animals.”

Some drone designers have moved beyond avian inspiration and are embracing straight-up mimicry. For example, in 2011, DARPA had the company Aerovironment build the Nano Hummingbird, a tiny drone that looks and moves like a hummingbird. (Unlike a hummingbird, it has a built-in camera.) The German company Festo based its SmartBird on a seagull. Maveric, a drone built for the Army, looks like a bird for a very obvious reason — camouflage. As the drone’s manufacturer told FlightGlobal, the drone was supposed to have a “natural, biological look. It wasn't supposed to look DoD-ish.”

Of course, taking inspiration from birds is nothing new for aviation engineers. The Wright Brothers dreamed up designs for their first plane by watching birds, and the new Airbus A350 XWB uses principles gleaned from sea birds to detect changing winds. But with drones, the lessons are particularly apt. Before long they’ll be sharing airspace with birds, so some structural and behavioral similarity makes sense. At the very least, it’ll help them work together when the TIE interceptors attack.