Fly-sized robot takes first controlled flight

Harvard researchers have successfully designed, manufactured and flown a tiny fly-inspired aerial robot.
The demonstration of the first controlled flight of an insect-sized robot is the culmination of more than a decade's work, led by researchers at the Harvard School of Engineering and Applied Sciences (SEAS) and the Wyss Institute for Biologically Inspired Engineering at Harvard.
"This is what I have been trying to do for literally the last 12 years," said Robert J Wood, principal investigator of the National Science Foundation-supported RoboBee project.
Inspired by the biology of a fly, with submillimeter-scale anatomy and two wafer-thin wings that flap almost invisibly, 120 times per second, the tiny device not only represents the absolute cutting edge of micromanufacturing and control systems.

"We had to develop solutions from scratch, for everything. We would get one component working, but when we moved onto the next, five new problems would arise. It was a moving target," said Wood.
Flight muscles, for instance, don't come prepackaged for robots the size of a fingertip.

"Large robots can run on electromagnetic motors, but at this small scale you have to come up with an alternative, and there wasn't one," said co-lead author Kevin Y Ma, a graduate student at SEAS.
The tiny robot flaps its wings with piezoelectric actuators - strips of ceramic that expand and contract when an electric field is applied.

Thin hinges of plastic embedded within the carbon fiber body frame serve as joints, and a delicately balanced control system commands the rotational motions in the flapping-wing robot, with each wing controlled independently in real-time.
At tiny scales, small changes in airflow can have an outsized effect on flight dynamics, and the control system has to react that much faster to remain stable.
The robotic insects also take advantage of an ingenious pop-up manufacturing technique developed by Wood's team in 2011.
Sheets of various laser-cut materials are layered and sandwiched together into a thin, flat plate that folds up like a child's pop-up book into the complete electromechanical structure.

"We can now very rapidly build reliable prototypes, which allows us to be more aggressive in how we test them," said Ma.