A Breakthrough in Soft Robot Muscles, Funded by the Military
A Breakthrough in Soft Robot Muscles, Funded by the
Military
A "soft robot" snake arm designed by Harvard's
Wyss Institute and MIT's CSAIL institute
BY PATRICK TUCKER NOVEMBER 27, 2017
Future military robots may come in softer, more cuddly,
and stranger forms.
Back-flipping robots made of metal and other hard
materials may be a big hit on YouTube, but future military robots may need
appendages that are far softer, stronger and flexible — more like natural
muscle tissue.
Funded in part by the Defense Advanced Research Projects
Agency, a team of researchers from the MIT Computer Science and Artificial
Intelligence Laboratory, or CSAIL, along with scientists from Harvard
University’s Wyss Institute, have created robot “muscles” that use hydraulics
rather than electric motors. These muscles are strong – the researchers say
their 2.6-gram robot muscle can lift a 3-kilogram object, like a “mallard duck
lifting a car” — and can shrink to 10 percent of their original size, all while
using much less power than typical metal-and-circuit robots.
The new soft robot muscles share a lot with animal muscle
tissue. Where humans have muscles, robots have what are called actuators,
little mechanisms that control movement. A humanoid robot with lifelike facial
expressions, for example, has a bunch of actuators buried beneath the surface
of the “skin,” working together to lift the bot’s eyebrows, the corners of the
mouth, etc.
Most robotic actuators are electric and run on battery
power — a lot of it. It’s one reason why many robots (and robotic exoskeletons
that also use electric actuators) are somewhat impractical in many military
settings. Who wants to carry multiple lithium-ion battery packs with them to
power their exoskeleton behind enemy lines?
The Wyss-CSAIL robo-muscles work via hydraulic actuators,
using water and air. They consist of a carefully designed “skeleton” of metal
or some other material folded into a vacuum-sealed bag. As air or water is
added or removed from the bag, the change in pressure causes the skeleton and
the skin to fold or unfold in a way that allows for gripping, pushing, or other
limited functions.
“One of the key aspects of these muscles is that they’re
programmable, in the sense that designing how the skeleton folds defines how
the whole structure moves. You essentially get that motion for free, without
the need for a control system,” Shuguang Li, a researcher at Wyss Institute and
CSAIL, said in a statement.
Moving away from electric actuators toward more organic
ones can also make robots easier to run, reducing the amount of computer
processing needed to get the robot to perform as intended, say the researchers.
“Incorporating intelligence into the body (via specific folding patterns, in
the case of our actuators) has the potential to simplify the algorithms needed
to direct the robot to achieve its goal. All these actuators have the same
simple on/off switch, which their bodies then translate into a broad range of
motions,” said MIT researcher Daniela Rus.
Lightweight, high-power muscles also broaden the range of
applications for robots, everything from soft exoskeletons for carrying heavy
loads longer distances to, potentially, small robots that can be ingested or
implanted in the body to perform specific biological tasks. The researchers
have shown that they can build the robo-muscles with a water-soluble polymer
that dissolves when no longer necessary (so it doesn’t stick around inside
longer than it needs to). And they can be scaled to almost any size.
Their paper (here’s a draft version) will appear in the
Proceedings of the National Academies of Sciences this week.
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