Harvard researchers develop robotic fly for use in surveillance, spying

Published 20 July 2007

Researchers develop an artificial fly whic h may be used in surveillance of battlefields, urban environments; the robot’s small size and fly-like appearance are key: “You probably wouldn’t notice a fly in the room, but you certainly would notice a hawk,” team leader says

We wrote last week about two Carnegie Mellon reseachers who developed a water-striding robot. Not to be outdone, Harvard University researchers have built a life-size, robotic fly. Weighing only sixty milligrams, with a wingspan of three centimeters, the robot’s movements are modeled on those of a real fly. The researchers say that much work remains to be done on the mechanical insect, but when completed, these small flying machines could one day be used as spies, or for detecting harmful chemicals. “Nature makes the world’s best fliers,” Robert Wood, leader of Harvard’s robotic-fly project and a professor at the university’s school of engineering and applied sciences, told Technology Review. The U.S. Defense Advanced Research Projects Agency (DARPA) is funding Wood’s research, hoping that it will lead to stealth surveillance robots for the battlefield and urban environments. The robot’s small size and fly-like appearance are critical to such missions. “You probably wouldn’t notice a fly in the room, but you certainly would notice a hawk,” Wood says.

Recreating a fly’s efficient movements in a robot roughly the size of the real insect is not easy because existing manufacturing processes couldn’t be used to make the sturdy, lightweight parts required. The motors, bearings, and joints typically used for large-scale robots would not work for something the size of a fly. “Simply scaling down existing macro-scale techniques will not come close to the performance that we need,” Wood says. Extremely small parts can be made using the processes for creating microelectromechanical systems, but such processes require a lot of time and money. Wood and his colleagues at the University of California, Berkeley, developed their own fabrication process, using laser micromachining, cutting thin sheets of carbon fiber into two-dimensional patterns that are accurate to a couple of micrometers. Sheets of polymer are cut using the same process, and by carefully arranging the sheets of carbon fiber and polymer, the researchers are able to create functional parts.

By fitting many little carbon-polymer pieces together, the researchers are able to create rather complicated parts that can bend and rotate precisely as required. To make parts that will move in response to electrical signals, the researchers incorporate electroactive polymers, which change shape when exposed to voltage. The entire fabrication process will be outlined in a paper appearing in an upcoming edition of the Journal of Mechanical Design (sub. req.).