The Flight of An Insect-Scaled Robot

The aerodynamic feats of insects do not interest most of us in the least — in fact, our first instinct would be to swat at any fly that hovers too close. But researchers from Harvard University have drawn inspiration from the maneuvers of these airborne creatures to design a lightweight flapping-wing robot, capable of controlled flight. They report their findings in this issue of Science.

The team led by Prof. Robert Wood of the Harvard School of Engineering and Applied Sciences invented an efficient way to fabricate these 80-milligram robotic insects. An origami-like technique lets them rapidly put together this device with its many layers of laser-cut materials and integrated electronics. Previously, these parts had to be assembled, part by part, by hand, under a microscope.

Getting these robots air-borne was the next step. The prototype has a pair of wings that flap thanks to piezoelectric actuators — ceramic strips that expand and contract in response to an electric field. The flapping frequency of 120 times per second generates enough downward moving air to lift the robot. The robot can  hover and steer on a preset path. Both power and control signals come through thin cables.

Putting a battery onboard would be nice but, like every other component on this robot with the carbon composite frame, it would have to be custom-made, says Sawyer Fuller, co-author of this paper. The post-doctoral researcher in Wood’s group elaborates: “Adding a battery would increase weight, but we think it will still be possible to carry it. Eventually, we will put a small, omnidirectional camera onboard — something like the eyes used by insects — so that the robot can see obstacles and avoid them.”

This robot, incapable as yet of independent flight, may be the first of a swarm of mechanical pollinators. RoboBees is the name of a National Science Foundation-funded project inspired by the Colony Collapse Disorder, an ailment that has struck honeybee colonies in many countries in the last decade. The drastic drop in the population of these insects brought together a team of interdisciplinary scientists – vision experts, biologists, material scientists and electrical engineers – who would collaborate to try and create robotic pollinators.

The larger goal of the RoboBees project is to try and understand the interaction between the body, brain and colony in insect swarms, says Prof. Gu-Yeon Wei. The robots could find practical use wherever larger numbers of these devices need to be deployed — not just in pollination, says Fuller. “It is relatively cheap to make many of them because even though they are made out of aircraft-grade materials, only minimal amounts of material go into the making of these devices.”

What the RoboBee can do presently, of course, is not even a patch on the ability of the real bee that deftly evades a swatting hand or land smoothly on a dandelion swayed by a gust of wind. We would like to understand their biology better and apply it to our own work, says Fuller.