Steerable microrobots could someday be used to explore
brain tissue
Zoe Elizabeth Buck
July 15, 2008 6:20 AM
MCT NEWSFEATURES
McClatchy Newspapers
(MCT)
RALEIGH, N.C. - Gas prices have auto manufacturers rushing
to make cars smaller, but Bruce Donald drives vehicles so tiny
you need a microscope just to see one.
Donald and his team of Duke University computer scientists
have constructed a fleet of fully steerable microrobots small
enough to move around on the head of a pin. Robots this small
could someday explore brain tissue or manipulate delicate
electronics.
The robots are about 250 microns long and 60 microns
across. They are thinner than the width of a human hair, and
you could line two of them end to end inside the period at the
end of this sentence.
They look like spatulas that move around on a charged
surface using small, springlike steps similar to an inchworm's
crawl. The microrobots have a long, thin arm that can be
lowered and used as a pivot for turning, allowing the machines
to steer freely in any direction.
The microrobots will soon be put to work probing the
architecture of animal brain cells. Donald is working with
Duke neurobiologist Richard Mooney and physicist Gleb
Finkelstein to put the little robots to work as drill rigs,
driving electrodes mounted on the front of the robots into the
cells. Eventually Donald hopes this technology can help
neurobiologists understand how the human brain works.
''Just like when the car first appeared and people saw all
sorts of uses for them, there are all kinds of applications
for something that can move around and do tasks at a
microscopic scale,'' Donald said. ''These microrobots will be
able to act as bulldozers, pick-up trucks and construction
machinery. They can drive around by themselves, and now we can
control large groups of them.''
Donald and his collaborators drive the microrobots in much
the same way that young children drive the remote-controlled
toy cars they use to terrorize parents and siblings.
''We send the same signal with instructions to the whole
group of microrobots,'' he said. ''Even though every robot
gets the same message, we constructed multiple types of
robots, which we call species. Each species has a slightly
different physics, so they will all react to the instructions
differently to carry out the task most efficiently.''
Ronald Fearing runs a microrobotics lab at the University
of California at Berkeley.
''I think of what professor Donald is doing as shrinking a
factory to the size of a computer chip,'' Fearing said. ''The
microrobots are like little workers and machinery that can
build things and fix things in the factory. This is really
neat when you're talking about components that can't be
handled by hand.''
With so many potential applications, the future of the
robots is unclear.
''The size is obviously a significant achievement,'' said
Dan Popa, assistant professor of electrical engineering at the
Automation and Robotics Research Institute at the University
of Texas at Arlington. ''But right now what Donald has is
mostly a curiosity. The next question is what these robots
will be used for, and what that is is not entirely
clear.''
Popa said he could see Donald's microrobots being used to
manipulate microscopic materials, a field called
nano-manufacturing.
Although the microrobots are only following instructions
right now, they are likely to start getting more intelligent
in the future.
''My students are working on installing circuits that would
allow the robots to do simple computations on their own,''
Donald said.
But there's no need to fear hordes of Donald's microrobots
taking over the world just yet.
''They're carefully engineered so that they can't escape
from the surface,'' he assured, ''so there's nothing to worry
about.''
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AP-NY-07-15-08 0855EDT
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