American engineers have designed a robot bird inspired by real birds

Steph Deschamps / December 3, 2021

A team of engineers at the prestigious U.S. Stanford University has created robotic clamps that can be attached to drones, turning them into robotic birds that can pick up objects or perch on various surfaces. These new capabilities could allow flying robots to conserve their batteries instead of having to hover for example, during search-and-rescue operations or help biologists more easily collect samples in the forest.
We want to be able to land anywhere, that's why it's exciting from an engineering and robotics point of view, David Lentink, co-author of an article about the innovation published Wednesday in the journal Science Robotics, told AFP.
As is often the case in robotics, this project was inspired by animal behavior in this case the way birds land and cling to branches to overcome technical difficulties. But imitating these birds, whose millions of years of evolution have enabled them to cling to branches of various sizes and shapes, sometimes covered with lichen or made slippery by the rain, is no easy task.
To this end, the Stanford team used high-speed cameras to study how small parrots landed on poles that varied in size and material: wood, foam, sandpaper and Teflon. The poles were also equipped with sensors that recorded the force with which the birds landed and took off again. 
The scientists found that while the landing motion was the same in each situation, the parrots used their feet to adapt to the variations encountered. Specifically, the birds wrap their talons around their perch and also use soft, wrinkled pads to ensure a good grip.
To be able to support a small drone with four propellers, scientists designed their claws based on the model of peregrine falcon legs. The structure, made using a 3D printer, includes motors and fishing line as muscles and tendons. It takes 20 milliseconds for the mechanism to latch on, and an accelerometer then tells the robot that the landing process is complete.
An algorithm finally allows the mechanical bird to keep its balance on the branch. The robot bird managed to catch objects thrown at it, such as tennis balls, and to land in real-life conditions in the forests of the northwestern United States.
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