Scientists built a flying robot that is both easy to control and energy-efficient, especially in changing wind conditions. The robot can change its shape and uses wind to stay in the air, instead of relying on thrust-generating motors.
(Nanowerk News) Current flying objects face a trade-off: Drones with propellers for instance are very agile and able to hover, however they use up a lot of energy. Airplanes on the other hand feature fixed wings which allow them to fly very efficiently. The downside: they can’t remain suspended in the air like a kestrel on the lookout for prey.
Scientists from the Max Planck Institute for Intelligent Systems (MPI-IS) in Tübingen and from the University of Stuttgart created a shape-changing flying robot named “Floaty” that can fly efficiently as well as stay stable in the air.
Floaty is inspired by birds which can glide and remain airborne by making use of wind currents and by simply adjusting their wings. Just like these animals, Floaty doesn’t utilize propellers to remain in the air
In a video, the robot is featured flying in a wind tunnel with speeds of up to 10 m/s. Floaty makes use of the fast-rising air from below and quickly changes the four movable flaps on its top. By rotating these adjustable flaps, the robot controls how air flows around it, changing the air resistance. This allows Floaty to balance itself, even if air pushes it sideways – without the need for active propulsion and high-power consumption.
Learned from many experiments inside the wind tunnel, Floaty relies on a learned aerodynamic model to precisely control itself and hover in place. It can successfully recover from physical pushes and wind disturbances.
„We believe our work opens up new ways of building flying robots that are more efficient and more sustainable,” says Ghadeer Elmkaiel, who is first author of the publication and a Ph.D. student in the Learning and Dynamical Systems Group at MPI-IS. “Instead of relying on thrust-generating motors, Floaty shows that robots can ride the wind intelligently, just like birds – saving a lot of energy while still staying controllable.”
Initially, the biggest challenge was making the robot naturally stable so it wouldn't flip over, while ensuring it remained easy to steer. During early wind tunnel tests, Floaty’s original flat shape caused it to tip over sideways instead of righting itself. To fix this, the researchers made two key design changes: they lowered the robot’s center of gravity and redesigned the rigid flaps by adding a precise bend. Thanks to these adjustments, Floaty is now naturally stable and automatically corrects its balance in mid-air.
“Our Floaty robot could be useful in many real-world situations where there are updrafts,” says Michael Mühlebach, who leads the Learning and Dynamical Systems Group and who is co-author of the publication. He gives several examples: “Floaty could inspect factory smokestacks where there is strong upward airflow. It could potentially work there with little modification. Similar technology could perhaps also help control rockets during re-entry, or it could help guide weather balloons. There are many ways in which the robot can take advantage of upward airflows to save energy.”
