Drones have become incredibly useful for photography, inspections, and deliveries.
They are highly maneuverable and can hover in one place, but they have a major weakness: they use a lot of energy.
Their spinning propellers need a constant supply of power, which limits how long they can stay in the air.
Airplanes have the opposite advantage.
Their fixed wings make them very energy efficient, allowing them to fly long distances while using relatively little power. However, airplanes cannot hover in one spot.
Now, researchers have created a flying robot that may combine some of the best qualities of both systems.
Scientists from the Max Planck Institute for Intelligent Systems and the University of Stuttgart have developed a shape-changing robot called Floaty that can remain stable in the air without using propellers.
The robot takes its inspiration from birds. Birds such as kestrels can appear to hang motionless in the sky while searching for prey.
They do this by taking advantage of rising air currents and making small adjustments to their wings rather than constantly flapping.
Floaty works in a similar way. Instead of using motors to generate lift, it uses upward-moving air. The robot has four movable flaps on its top surface. By rotating these flaps, Floaty changes how air flows around its body. These adjustments alter air resistance and allow the robot to control its position.
The researchers tested Floaty in a wind tunnel with air speeds of up to 10 meters per second, or about 36 kilometers per hour. The robot successfully balanced itself even when the airflow pushed it from the side. It could also recover after being physically nudged or disturbed by changing winds.
To achieve this, the team trained the robot using data from many wind tunnel experiments. Over time, Floaty learned an aerodynamic model that allows it to predict how changes in its flaps affect its movement. This enables the robot to make precise adjustments and remain suspended in the air.
Building the robot was not easy. Early versions of Floaty had a flat design that made them unstable. Instead of correcting themselves, they often tipped over sideways.
The researchers solved this problem by making two important changes. First, they lowered the robot’s center of gravity, making it less likely to flip.
Second, they redesigned the flaps by giving them a carefully calculated bend. These changes allowed Floaty to naturally stabilize itself and automatically regain balance while flying.
The scientists believe this technology could have many practical uses. Floaty could inspect factory smokestacks, where strong upward air currents already exist. Similar ideas might also help control rockets as they reenter Earth’s atmosphere or guide weather balloons more efficiently.
Perhaps most importantly, Floaty shows that flying robots do not always need energy-hungry propellers. By learning to ride the wind like birds do, future robots may be able to stay airborne for much longer while using far less energy.
