PREVIEW

Scientists in Switzerland have built a revolutionary robot raven that leaps into flight like a bird.

They hope that one day the design could eliminate the need for runways for small fixed-wing drones or eVTOL craft.

Inspired by birds, which use powerful leg thrusts to launch into the air, researchers led by Dr Won Dong Shin created ‘RAVEN’, a robot capable of achieving similar feats to its avian namesake.
“Most birds can navigate seamlessly between aerial and terrestrial environments,” the scientists write in their paper. “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.
“These capabilities have inspired engineers to aim for similar multimodality in aerial robots, expanding their range of applications across diverse environments.”
Until now, building a machine able to endure the immense forces involved when a bird springs from its feat has proven challenging.
They add: “However, challenges remain in reproducing multimodal locomotion, across gaits with distinct kinematics and propulsive characteristics, such as walking and jumping, while preserving lightweight mass for flight. This trade-off between mechanical complexity and versatility limits most existing aerial robots to only one additional locomotor mode.”
However, Dr Shin and his team at the Swiss Federal Institute of Technology Lausanne’s (EPFL) propeller-powered robot can walk, hop, and jump into flight using legs designed to mimic a bird's motion.
RAVEN’s legs, while inspired by birds, have been simplified. Unlike real bird legs, which have multiple joints at the hip, knee, and ankle, its legs feature just two joints at the hip and knee, powered by small motors. Springs in each foot store and release energy to aid the jump. This streamlined design helps keep the robot’s weight to just 600 grams – similar to a crow.
The scientists explain: “RAVEN (Robotic Avian-inspired Vehicle for multiple ENvironments), which uses its bird-inspired multifunctional legs to jump rapidly into flight, walk on the ground, and hop over obstacles and gaps similar to the multimodal locomotion of birds.”
In tests, RAVEN managed to jump nearly half a metre into the air, reaching a speed of 2.4 metres per second – comparable to similarly sized birds. Once airborne, its propeller kicks in to maintain flight. This ability to take off vertically from almost any surface could make RAVEN particularly valuable in disaster relief missions, where traditional drones struggle to land or take off.

However, there’s still work to be done as Dr Shin acknowledges that the next step will be perfecting RAVEN's ability to land safely.