DelFly Nimble : a new robot that can fly like a real insect. Flying insects like bees, dragonflies, and fruit flies can perform impressive aerodynamic feats. Particularly when seeking to evade predators or the swatting motion of a human hand. Dutch scientists have successfully built a flying robot capable of executing similar maneuvers. Despite the robot being much larger than the average. It that could shed light on how these creatures achieve those feats. The scientists described their work in a new paper.
There was a time when scientists believed that insect wings worked a lot like airplane wings. The up and down motion of their wings would generate lift because air flowing over the wing follows its slightly tilted surface. While the downward flow lowers the air pressure above the wing, lifting it just enough to keep the body aloft. But in the 1990s, a zoologist named Charles Ellington decided to test this theory by putting various insects in actual wind tunnels. The conventional lift they measured simply wasn’t sufficient to account for their ability to fly.
Ellington’s subsequent research showed that a stable leading-edge vortex is the most likely explanation for how insects stay aloft. Once the vortex forms, it spirals out along the wing toward the tip, drawing air outward so as to avoid a stall. That explains how insects generate lift to hover, but not how they manage to execute complicated maneuvers? That’s possibly due to how an insect wing can rotate to slightly get rid of the vortex for an extra bit of lift. This enables the insect to change direction. But there is still plenty of mystery remaining for scientists to explore. And that’s where this new flying robot comes in.
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Matej Karasek of the Delft University of Technology in The Netherlands has long been intrigued by the agility of flying insects. He used them as inspiration to develop tail-less flapping-wing robots. “The major challenge was to come up with a wing actuation mechanism that would allow independently controlling body rotations around the three body axes,” he says. And that mechanism had to be sufficiently lightweight for the robot to be able to carry it. The flight of fruit flies provided the key. Karasek programmed his robot to mimic their hypothesized flight biomechanics.
It worked like a charm, and the result is the prototype DelFly Nimble flying robot. The robot’s wings beat 17 times per second, generating lift. Also making the robot capable of controlling flight direction by slight adjustments in wing motion. It can hover and fly in any direction as well as perform banked turns and 360-degree flips, akin to loops or barrel rolls. All this, just like a fruit fly, despite being significantly larger than the insect. It also boasts excellent power efficiency, capable of hovering for five minutes or flying more than a kilometer on a single charge. So there is no need for a feedback mechanism for fruit flies to perform their evasive maneuvers as quickly as possible.
Insect-inspired drones hold a lot of potential because they can fly more efficiently, with better maneuverability, than the standard drones currently available. The DelFly Nimble is also relatively cheap to manufacture since it builds on existing manufacturing processes and uses off-the-shelf components.