For
years now, scientists have sought to build aerial robots inspired by
bees and other flying insects. But they have always run into a
fundamental problem: Flying takes a lot of energy.
Insects
flap their wings, generating the thrust needed to move through the air
by utilizing the energy stored in strong muscles. Their robot
doppelgängers must rely on batteries, which are less efficient and tend
to be heavy, or must be hooked up externally.
Now
researchers at Harvard University have built a new type of robot that
is capable of true, untethered flight. The unit, called the RoboBee
X-Wing, is equipped with four tiny wings made of carbon fiber and
polyester, and even tinier photovoltaic cells.
In
bright light, its solar cells generate about five volts of electricity,
which a minuscule transformer then boosts to the 200 volts necessary
for liftoff. When the high voltage is applied to two components called
piezoelectric actuators, they bend and contract, much as an insect’s
muscles would. This drives the flapping motion of the RoboBee’s wings.
Clever
engineering keeps the device small and light — about one-quarter the
weight of a paper clip. This allows the RoboBee to flit about freely,
whereas previous iterations of the robot could only take off, land, or perch mid-flight while leashed to a power supply.
“We
wanted to keep pushing the limit on how much power we could squeeze out
of the artificial muscles in the robot, and how efficient we could make
the whole system,” said Noah Jafferis, a postdoctoral engineer at Harvard and one of the leaders of the research.
On Wednesday, Dr. Jafferis and his colleagues reported in Nature that the RoboBee is now able to match the thrust efficiency of similarly sized insects, such as bees.
The
first time the robot took off in the lab, it lifted off with such force
and speed that some of the researchers yelped in surprise. “We weren’t
expecting it to take off like that at all,” said Farrell Helbling, a postdoctoral roboticist who also led research on the seminal flight.
So
far, each of the RoboBee’s test flights have only lasted a couple
seconds. One of the robot’s shortcomings is that it still can’t store
energy. As soon as it flies out of a small, well-lit area, it slows down
and falls to the ground.
But
Dr. Helbling and Dr. Jafferis are confident that the robot could stay
aloft for several minutes if its solar cells and circuits were given the
proper tweaks.
Further advances in engineering could make microrobots even more autonomous, said F.
Zeynep Temel, who works on ant-sized jumping robots at Carnegie Mellon
University. And once these tiny robots are able to zip up, down and
sideways outdoors, they could be used to take air quality measurements,
help search collapsed buildings for survivors, or even be deployed in swarms.
“Having onboard power is the first big step to getting microrobots out of the lab and into the real world,” Dr. Temel said.
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I suggest comparing the above article with p. 116 of my book CHAMELEO: A STRANGE BUT TRUE STORY OF INVISIBLE SPIES, HEROIN ADDICTION, AND HOMELAND SECURITY. It's also worth noting (as political researcher Dave Emory is fond of pointing out) that the military is generally fifteen to twenty years ahead of the civilian world when it comes to technological developments.
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