Tiny Fly Beats Robots
Fruit flies dart, circle, zig and zag rapidly. Researchers gain some insight into how they do it so efficiently.
Researchers at Penn State have learned some amazing things about fruit flies. Their wings beat as fast as a blur, but they can orient their heads four times faster than the wings beat. They found this out in a flight simulator with high-speed cameras.
By examining how fruit flies use eye movements to enhance flight control with a staggeringly fast reaction speed — about 30 times faster than the blink of an eye — Penn State researchers have detailed a framework to mimic this ability in robotics….
The fly uses its eye movements to coordinate its wings in response to what it is seeing. Researchers developed a flight simulator to test they fly’s responses to moving objects in the visual field. They tethered the fly’s thorax to an overhead post, allowing the wings to flap and the head to move. This enabled them to watch, using a high-speed camera, how the head moved in relationship to the wings. Films recorded with the setup show the head rapidly moving side to side, four times faster than the wings were flapping.
Eye on the Ball
Current robot designs use stationary sensors on the head. The fly uses a different approach: it uses active eye movements that allow it to quickly sense its visual field in order to scan its environment. Humans do this too but at a much slower rate.
In support of this theory, the researchers determined the eyes of the fruit fly were able to react four times faster than the body or wings of the animal. These reactions were also tightly coupled, demonstrating that flies rely heavily upon eye movements to coordinate their wing movements.
“We’ve shown that their eyes can control and stabilize their vision better than we originally thought, by reducing motion blur,” Cellini said. “Like in sports, they teach baseball players to follow the ball with their eyes to reduce blur and increase batting performance.”
A video clip in the press release overflows with praise for the abilities of one of the smallest, humblest of insects. “If we look at the best man-made… insect-scale robots,” one of the team members says, “they pale in comparison to what flies and other small insects can do.” For instance, they can land upside down on ceilings. “Nothing we’ve designed as humans comes even close” to doing that.
Their paper is published in PNAS:
Cellini and Mongeau, “Active vision shapes and coordinates flight motor responses in flies.” PNAS September 1, 2020 https://doi.org/10.1073/pnas.1920846117.
The team took interest in fly aerodynamics in order to improve human technology.
“If you are able to study flies doing what they do best — flying — you can find some incredible engineering solutions that already exist in biology,” said Benjamin Cellini, a doctoral student studying mechanical engineering and the first author of the paper.
Maybe there will be fruit-fly-inspired technology on Mars some day. The evolution-free video and article ends,
“In engineering, you are taught to apply principles from mathematics and physics to solve problems,” Cellini said. “If you want to build a robot to fly on Mars, you can use engineering concepts to provide potential solutions. But we don’t always have to develop ideas from scratch; we can also seek inspiration from nature.”
For tiny flyers that we tend to brush off or even swat at, “flies can do some amazing tasks,” the scientist notes. Gnats are even smaller. They can fly in swarms without colliding – reminiscent of the starlings in Illustra’s film, Flight: The Genius of Birds. This shows that the Creator of nature’s flight technology knows how to scale it up or down. Whether in birds or in insects, rapid eye-wing coordination is required for such stunning displays of formation flight.