This Crow-Inspired Energy-Efficient Robo-Bird Drone Design Has Legs — Literally

Researchers at the École Polytechnique Fédérale de Lausanne (EPFL) and the University of California at Irvine have come up with a drone design that can easily switch between ground-based and aerial locomotion — by, effectively, building a robot bird dubbed RAVEN.

"Most birds can navigate seamlessly between aerial and terrestrial environments. Whereas the forelimbs evolved into wings primarily for flight, the hindlimbs serve diverse functions such as walking, hopping and leaping, and jumping take-off for transitions into flight," the team explains of its work. "These capabilities have inspired engineers to aim for similar multimodality in aerial robots, expanding their range of applications across diverse environments."

Previous efforts to create a design mimicking the flexibility of actual birds, though, have suffered from excessive mechanical complexity when it comes to handling more than a couple of different locomotion modes. That's where the researchers come in with RAVEN, the Robot Avian-inspired Vehicle for Multiple Environments — delivering the ability to walk, hop, and leap into flight.

"We show that jumping for take-off contributes substantially to the initial flight take-off speed," the researchers say of their experimentation, "and, remarkably, that it is more energy efficient than taking off without the jump. Multifunctional robot legs expand the opportunities to deploy traditional fixed-wing aircraft in complex terrains through autonomous take-offs and multimodal gaits."

The team's work has been published in the journal Nature under closed-access terms; additional information is available in an article on IEEE Spectrum covering the work.