Thursday, May 21, 2009

Technology Transfer: The Flight of a Fly

Insect flight is fascinating. It seems to defy engineering principles and the old joke is that it is impossible. (As body size reduces the lift force becomes weaker than the body weight, and viscosity effects also cause problems). Now we understand better how it can be possible, and we're continuing to learn more of the details. A recent paper reporting on creative new research on insect flight control reveals some interesting aspects of the visual flight speed response in fruit flies. Insects, like subatomic particles, are difficult to measure without disturbing. Past experiments often relied on tethering the flies–hardly a natural environment. This new paper reports on research using a wind tunnel with controlled light patterns to better understand how the fly's visual system controls flight. The researchers found that:

To control flight speed, the visual system of the fruit fly extracts linear pattern velocity robustly over a broad range of spatio–temporal frequencies. The speed signal is used for a proportional control of flight speed within locomotor limits. The extraction of pattern velocity over a broad spatio–temporal frequency range may require more sophisticated motion processing mechanisms than those identified in flies so far. ... Finally, the high-level control principles identified in the fly can be meaningfully transferred into a robotic context, such as for the robust and efficient control of autonomous flying micro air vehicles.

In recent years autonomous, uncrewed flight vehicles have become increasingly common. Of course leaving out the crew can be useful for dangerous missions, but the absence of any personnel also allows for very small vehicles. There are applications for micro flight vehicles, and this work adds to a growing body of research on how the sophisticated designs of insects can be of use in such vehicles.