This video of an ornithopter from Harvard University and the University of Tokyo has been making its way around the internet, and while it’s pretty amazing to see those bio-inspired flapping wings, I thought I’d share a slightly different perspective on this ‘robotic butterfly.’ Wired magazine spoke with Robert Dudley, a professor at UC Berkeley who specializes in biomechanics.
Butterfly flight is somewhat mysterious because it’s roughly the opposite of “as the crow flies.” Butterflies flit about rather than flying in a straight line. That actually costs them more energy, Dudley said, so scientists assume their looping flying serves some evolutionary purpose.
“The advantage is that it’s thought to be an anti-predator behavior,” Dudley said. “The claim is that irregular flight paths are a permanent signal of prey unprofitability.”
The Japanese researchers somewhat capture this oscillating type of flight with their plastic-winged flyer, but Dudley argued that the differences between the bot and a real butterfly are so great as to invalidate the biological lessons the researchers try to draw.
“There is nothing fundamentally wrong with this approach but it severely limits any claims to the biology,” Dudley said.
This is really interesting, from an evolutionary point of view… Basically, butterflies flit about randomly like they do because it makes them a pain in the butt to catch. The extra energy that they expend doing this is made up for by the fact that they don’t get eaten as frequently. Anyway, back to robots.
It seems to me as though the scope of this particular research has been somewhat misemphasized… The researchers look to have been experimenting with the dynamics of butterfly wings, as opposed to attempting to create a robotic butterfly that flies like a real one. Specifically, they were looking at the wing veins, and as it turns out, “a mimic wing with veins generated a much higher lift coefficient during the flapping flight.”