Last summer, in a Harvard
robotics laboratory, an insect took flight. Half the size of a paper clip,
weighing less than a tenth of a gram, it leapt a few inches, hovered for a
moment on fragile, flapping wings, and then sped along a preset route through the
air. 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. 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,
but is an aspiration that has impelled innovation in these fields by dozens of
researchers across Harvard for years.
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. Applications of the project could
include distributed environmental monitoring, search-and-rescue operations, or
assistance with crop pollination, but the materials, fabrication techniques,
and components that emerge along the way might prove to be even more
significant (i.e. the pop-up manufacturing process could enable a new class of
complex medical devices).
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