Video: Drone with legs can perch on a branch
Is that a bird or a drone watching you from the telephone wire? A drone with legs can perch just like a bird 鈥� or land and walk on flat surfaces. Bhargav Gajjar of in Brighton, Massachusetts, designed the legs as an add-on for small US air force drones.
Small drones generally lack landing gear. Many rely on a controlled crash-landing, a somewhat crude approach compared with the elegant precision landing of a perching bird. Gajjar studied dozens of bird species and recorded their landings using a high-speed camera. His drone鈥檚 legs are based on those of the American kestrel.
The drone perches in an upright position with a powerful gripping action from an electric motor. Its claws are extremely sharp so that its grip is difficult to break.
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A remote computer uses footage from a camera fitted to the drone to control flight and get the drone into the correct position for landing. Just like a real bird, the drone has to brake sharply just above its landing site and perform a controlled stall in order to touch down. Birds鈥� legs also act as shock absorbers, and the mechanical version mimics this.
Gajjar鈥檚 perching legs can waddle short distances, so the drone can explore indoor spaces.
Stealthy watcher
A perching drone can occupy any convenient vantage point, making it stealthier and giving a closer view than one circling overhead. Perching uses no power, and a perching drone recharging from solar cells could operate indefinitely. Gajjar has flown his legs on fixed-wing drones, but is using a quadrotor inside the laboratory.
Copying animals in ways like this appeals to Justin Thomas of the University of Pennsylvania鈥檚 General Robotics, Automation, Sensing and Perception (GRASP) Laboratory. 鈥淪uch a biomimetic approach would have advantages in extending the working time of an aerial robot by allowing it to perch and save energy,鈥� he says. His team has previously created a drone that can grab objects on the ground.
鈥淭his could be particularly advantageous for applications such as environmental monitoring and establishing temporary communication networks, such as in the case of a natural disaster,鈥� Thomas says.
