The innovation can expand the range of potential environments accessible to unmanned aerial vehicles.
The Laboratory of Intelligent Systems, led by Dario Floreano, in EPFL’s School of Engineering has named their device RAVEN (Robotic Avian-inspired Vehicle for multiple ENvironments).
Designed based on perching birds like ravens and crows that frequently switch between air and land, the multifunctional robotic legs allow it to take off autonomously in environments previously inaccessible to winged drones.
“Birds were the inspiration for airplanes in the first place, and the Wright brothers made this dream come true, but even today’s planes are still quite far from what birds are capable of,” says LIS PhD student Won Dong Shin. “Birds can transition from walking to running to the air and back again, without the aid of a runway or launcher. Engineering platforms for these kinds of movements are still missing in robotics.”
RAVEN's design maximises gait diversity while minimising mass. Inspired by the proportions of bird legs, Shin designed multifunctional avian legs for a fixed-wing drone.
He used a combination of mathematical models, computer simulations, and experimental iterations to achieve an optimal balance between leg complexity and overall drone weight (0.62kg). The resulting leg keeps heavier components close to the ‘body’, while a combination of springs and motors mimics powerful avian tendons and muscles.
Lightweight avian-inspired feet composed of two articulated structures leverage a passive elastic joint that supports diverse postures for walking, hopping, and jumping.
“Translating avian legs and feet into a lightweight robotic system presented us with design, integration, and control problems that birds have solved elegantly over the course of evolution,” Floreano says. “This led us to not only come up with the most multimodal winged drone to date, but also to shed light on the energetic efficiency of jumping for take-off in both birds and drones.”
