Robo Falcon 2.0: Robot falcon takes off like a bird of prey

A Chinese team of scientists has redesigned the Robo Falcon robot falcon, which was developed in 2021, so that it can now take off like a real bird and also fly more slowly. To achieve this, the researchers developed a wing-flapping mechanism that imitates that of birds even more accurately. The flying robot, now called Robo Falcon 2.0, can take off independently and also fly at low speeds.

The Robo Falcon 2.0 weighs around 800 g, as the scientists write in the study “Flapping-wing robot achieves bird-style self-takeoff by adopting reconfigurable mechanisms,” which was published in Science Advances. The wing system is now more complex and can combine wing beats, swings, and folds in a single stroke.

Many previous bio-inspired flapping-wing robots are based on a mechanical wing structure that has only one degree of freedom. The flight principle is thus more similar to the symmetrical hovering of insects and hummingbirds. However, larger birds and bats use wing kinematics that have three degrees of freedom. This allows flapping, swinging, and folding to be performed in a single flight movement. This should also enable more complex takeoff, landing, and flight maneuvers.

The wing mechanics developed by the Chinese scientists use reconfigurable mechanisms that employ decouplers to enable wing flapping, swinging, and folding in a single movement.

“These mechanisms enable the Robo Falcon 2.0 to take off and fly forward using belly-close forward wing beats and upward wing beats that generate lift and thrust, i.e., performing a bird-style takeoff. The swing and fold amplitude of the wings can also be adjusted to control pitch and roll movement during wing flapping,” the researchers say.

Flapping wing mechanism in practice

The scientists tested the robot's flapping wing mechanism in simulations, wind tunnel tests, and flight tests under real-world conditions. In the simulations and wind tunnel tests, they were able to prove that their system works: the mechanical increase in wing pitch increased lift and significantly improved the pitch movement of the robot falcon. This makes pitch control easier and better. The researchers could confirm this in practical flight tests.

Although the Robo Falcon 2.0 can now take off independently, the scientists admit that there is still room for improvement. At higher speeds, for example, an elevator is needed to achieve greater flight stability. Furthermore, energy efficiency during takeoff is not yet at the level of real birds or miniature insect-sized flying robots. The scientists also say that hovering ability is not as good because yaw control is currently still limited.

(olb)