Video: Model butterfly

Just like the real thing (Image: OpenCage/Flickr)

For the first time, engineers have created a model that flies just like a real butterfly.

Powered only by an elastic band, it flits up and down and flaps its wings languidly – just like the swallowtail butterfly it was modelled on. The band powers a mechanical crank that drives the wing motion.

“To our knowledge, our model is the first free-flying replica that has the same basic dimensions, mass and shape as a real insect,” says Hiroto Tanaka of Harvard University’s microrobotics lab, who designed the model with Isao Shimoyama of the University of Tokyo, Japan.


“We achieved the same mass, same flapping frequency and the same wing shape and stiffness as a real swallowtail, and found that realistic flight happens passively, by default,” says Tanaka.

The researchers say their objective is simply to study the flight mechanisms of butterflies in more detail. For instance, they discovered that mimicking the veins of the real butterfly gave the artificial version more lift than un-veined wings.

Spoilsports

But the pair aren’t planning to mass-produce the butterflies as toys. “It’s a one-off creation,” says Tanaka. Nor have they given it an exotic name. “In our previous presentations at conferences, we called it a butterfly-type ornithopter, or BTO,” he says.

The team claim it’s the first flying replica insect which matches the real thing in size and weight, though other flying robotic insects have been created. In 2008, the Harvard lab produced a robotic fly, and other researchers have also created tiny hovering robots based on insects since then. Other teams are developing insects for exploring hazardous environments and even other planets.

Journal reference: Bioinspiration & Biomimetics, DOI: 10.1088/1748-3182/5/2/026003