Insect avionics to keep aircraft from crashing
Bees use optical flow to measure speed and height while landing; a similar digital feedback loop attached to aircraft could save lives; researchers at the University of the Mediterranean solicit interest from helicopter manufacturers
For the past few weeks we have reported incessantly on studies demonstrating that the wing structures of the birds, the bees, and the bats offer useful studies of how a micro air vehicle (MAV) might achieve sufficient lift to pull its small frame off the ground. As it turns out, our winged friends are even more useful than that, leading us to wonder if entomology and ornithology might become established disciplines in the homeland security field. In the most recent breakthrough to come to our attention, scientists at the University of the Mediterranean in Marseilles have shown that the same technique used by insects to zoom about without crashing to the ground could provide a simple replacement for the complicated avionics in small aircraft.
According to scientist Nicolas Franceschini, as insects fly forward they monitor the ground below them, with the “optical flow” providing critical cues about height and speed. “The higher an insect’s altitude, the slower the optical flow; the faster it flies, the faster the optical flow.” From the insect’s perspective, the key when descending is to maintain a constant optical flow by monitoring the height-to-ground-speed ratio so that the insect slows down to just the right speed while landing. This explains why bees can drown while flying over still water. As the water provides no surface features with which to measure the optical flow, the bee instinctively descends much further than normal, resulting in certain death.
In order to prove that a similar method could assist UAVs and other small craft, Franceschini and his colleagues outfitted a miniature helicopter with a simple feedback loop that mimicked an insect’s ability to indirectly measure the height to ground speed ratio. With the minicopter tethered to the ceiling, a downward-pointing camera recorded the craft’s angular speed and adjusted its height to keep that speed constant. If the helicopter approached the ground, for instance, it would register a faster angular speed and ascend to throttle back. Franceschini is now in discussions with helicopter manufacturers about developing such optical flow regulators for their aircraft.
-read more in Duncan Graham-Rowe’s New Scientist report
