A robotic fly hovering for 7 seconds during a flight experiment. U.S. quarter shown for scale. | Video courtesy of Kevin Ma, Pakpong Chirarattananon

Small, winged insects, like flies and honeybees, are capable of unique and agile flight maneuvers that allow them to avoid flyswatters and land upon flowers blowing in the wind. For this reason, their aerial prowess has been extremely difficult to reproduce in the laboratory.

Now, Kevin Ma and colleagues from the School of Engineering and Applied Sciences and the Wyss Institute for Biologically Inspired Engineering at Harvard University have designed a miniature robot equipped with flapping wings that can hover in place and perform some of the same, sophisticated moves that insects pull off in nature. It’s the first robot of its kind, and the researchers say that it required some non-traditional approaches to propulsion, actuation and manufacturing.

The report describing their biologically inspired “RoboBees” is published in the 3 May issue of the journal Science.

“Large robots can run on electromagnetic motors,” Ma explained in a press release from Harvard University. “But at this small scale you have to come up with an alternative, and there wasn’t one.”

The researchers applied smart composite microstructures and used piezoelectric materials, or those that convert an electrical charge into mechanical stress, to develop the robot’s miniature wings. They also inserted thin hinges of plastic into a carbon fiber body frame to serve as joints, and developed a remote control system that directs each of the robot’s wings independently.

The mechanized insect remains tethered to a small, off-board power source since Ma and his colleagues estimate that it would only be able to fly for a few minutes using an on-board source. There simply aren’t any fuel cells small enough to be mounted on the robot’s body that could power its mechanical flight for longer stretches, they say.

Five individual robotic flies of identical design are shown alongside a U.S. penny for scale, demonstrating that the manufacturing process facilitates repeatability and mass production. | Image courtesy of Kevin Ma, Pakpong Chirarattananon

In their current form, the researchers’ prototypes consume approximately 19 milliwatts of electricity during their flights, which is roughly consistent with the energy expended by similarly sized insects.

The winged robots offer a new way to study flapping-wing flight mechanics and control at the insect scale, and the researchers suggest that its design could inform future studies of miniaturized power, sensing and computation technologies. They also imagine that their RoboBees could find work in environmental monitoring, search-and-rescue operations and even crop pollination.

“This work is a beautiful example of how bringing together scientists and engineers from multiple disciplines to carry out research inspired by nature and focused on translation can lead to major technical breakthroughs,” Wyss Founding Director Don Ingber concluded in the press release.

Links

Read the abstract, “Controlled Flight of a Biologically Inspired, Insect-Scale Robot,” by Kevin Ma et al.