Falcon-inspired drone uses claws to perch and grab objects
Nature is an endless source of inspiration for robot design, so of course flying robots will borrow heavily from birds. Engineers at Stanford have now developed robotic claws inspired by the talons of a falcon that let drones perch on many different surfaces, as well as grabbing or catching objects.
Birds have been shaped by millions of years of evolution, giving drone designers plenty of ideas for corners to cut. Adding feathers, morphing wings or streamlined bodies can make drones more efficient flyers – but how about landing? Most multirotor drones need a clear landing pad, and can’t make use of different surfaces. Birds, on the other hand, can swoop in and perch on a wide variety of surfaces and shapes without thinking about it.
So for the new study, the Stanford researchers set out to design a pair of birdlike legs that could grant drones the same versatility. They named the system Stereotyped Nature-inspired Aerial Grasper (SNAG), and it’s based specifically on the legs and claws of a peregrine falcon.
SNAG has motors that act like muscles, and wires that act like tendons. The leg absorbs the landing impact, and causes the claws to snap shut around the perch within 20 milliseconds. The ankle then locks, and an accelerometer registers that the robot has come to a stop. A balancing algorithm then stabilizes the robot so it doesn’t somersault straight off the front of the perch.
The researchers say that the system allows flying robots to come to rest on surfaces under a variety of conditions. Tests in a forest showed that SNAG could land and hold onto branches of different thicknesses, textures, bumps and offshoots, and whether dry or slick with water. In other tests, the team showed that these responsive claws could catch objects thrown at it, like bean bags and tennis balls.
The team says that SNAG systems could help drones come to rest and possibly recharge between flights, to extend their range. Or they could be used to carry cargo, picking up and putting down objects without needing to come to a stop.
The research was published in the journal Science Robotics. SNAG can be seen in action in the video below.