Flying robots are commonplace these days, from military drones to tiny helicopters that dance in the air, but none of them can flap their wings and then perch on a person's hand — until now.
At the University of Illinois at Urbana-Champaign, professor Soon-Jo Chung and postdoctoral researcher Aditya A. Paranjape designed a birdlike airplane that lands with precision.
Most aircraft (and robots) either fly like a helicopter or like a plane. Airplanes land the way they do because they need to lose lift, which they do by slowing down, but if they slow down too much they just drop out of the air and crash.
Birds are different. To land a bird will glide toward a landing point and then pull up steeply. At the same time the bird's decelerating, it's also climbing rapidly. Unlike airplanes, birds don't have vertical tails, so they have to use their wings to stabilize themselves.
A plane that can fly like a bird, land in a specific place, and launch itself again would offer the precision of a helicopter and the endurance of a fixed-wing craft. (Helicopters can't stay in the air as long as winged aircraft because they use a lot more power when flying).
Flapping wings also conserve power. Bird-like wings can be reoriented in a way fixed ones cannot, and that means it is much easier to maneuver air currents while gliding.
Other roboticists have built bird-like machines or tried and duplicate the way birds and other animals land. MIT has built a glider that can land on a wire, and at Stanford a team designed one that can land on vertical surfaces. And of course, a helicopter can land at any point by just hovering and setting down. But none have yet used the flapping motion of a bird's wings and duplicated the perching action.
Chung and Paranjape have demonstrated the bird-like craft can flap its wings, fly a short distance and perch on someone's hand. In the associated paper (download PDF here), they say this kind of capability would be useful for small robots that have to fly around humans.
Image: University of Illinois / Didier Cauvain