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Researchers at the University of California at Berkeley are
building a minuscule robot guaranteed to give new meaning to the old phrase,
``fly on the wall.''
Known affectionately as ``robofly,'' the gadget is exactly
what its name implies: a flying robot about the size of a housefly. It even
looks a bit like a fly, although it will have four wings instead of two and one
glassy eye instead of two beady ones.
Uncle Sam, who is bankrolling the project to the tune of $2.5
million and wants to see robofly airborne by 2004, will add the flying robot to
its espionage toy box.
``The potential application of a robot based on a fly might
be, in an urban environment, clandestine surveillance and reconnaissance,'' said
Teresa McMullen of the Office of Naval Research.
In other words, that fly might be a spy. Just the thing for
keeping tabs on terrorists. Or wandering spouses.
Its creators are not mad scientists but Ph.D.s. They envision
a nifty gizmo that will do all sorts of wonderful things, like fly through the
rubble of an earthquake searching for survivors.
``I really do envision, in every fire station, a jar of
robotic insects,'' Michael Dickinson, a biologist working on the project, said
with a perfectly straight face. ``You could scatter them around and have them
send a signal when they find something.''
But why a fly? Because the aerodynamic principles that keep
747s aloft do not work on such a small a scale.
``If we want to develop something with stealth, we have to
look at nature,'' McMullen said. ``There are no man-made objects that small that
can fly.''
But why a fly? Why not something with a little more pizzazz
like, say, a dragonfly?
Two reasons, said Ron Fearing, the top gun behind the
micromechanical flying insect. First, dragonflies have four wings.
``That automatically doubles the complexity of the project,''
Fearing said.
More importantly, flies, for all their faults, are outstanding
pilots. They can take off and land in any direction, even upside down. They can
change course in just 30-thousandths of a second. And they process information
at speeds that make a supercomputer look like an abacus.
``They're the fighter jets of the animal world,'' Fearing
said.
Robofly will weigh about 43 milligrams -- roughly the weight
of a fat housefly. Its body will be made of paper-thin stainless steel and its
wings of Mylar, which looks and feels a lot like Saran Wrap.
``Instead of gears and cogs and cams, we're using pieces that
are more like origami,'' Dickinson said.
Robofly will be powered by the sun, and a tiny device called a
piezoelectric actuator will flap its four puny wings 180 times a second.
Fearing and his pals cleared their first big hurdle in April
when Dickinson figured out how flies fly. It was a question that had perplexed
researchers for decades, and Fearing sheepishly admits that he had no clue how
flies fly when he pitched robofly to the Office of Naval Research.
Lucky for him that Dickinson solved the riddle. Dickinson
discovered that insects use three different wing motions that, taken together,
create backspin and air vortices that create lift. The complexity of the
movement means robofly will need four wings to do what flies do with two.
That problem solved, Fearing is scratching his head trying to
figure out how to control robofly once it is airborne. After all, there is not
much use for robots that can only hover over a desk.
``Flies have 100 million years of evolution to tell them how
to fly,'' Fearing said. ``We're not going to be there instantly.''
He is hoping to crib from colleagues at California Institute
of Technology in Pasadena who are developing tiny gyroscopes just one millimeter
in diameter. And some of the tricks Caltech researcher Kris Pister is developing
for ``smart dust'' -- which will pack sensors, communicators and computing power
onto tiny silicon motes -- also could come in handy.
Robofly was hatched in early 1998, when the Office of Naval
Research sought ideas for tiny robots. Fearing, who has been fascinated by
robots since he was a teenager, jumped at the chance.
He got together with some colleagues who let their
imaginations run wild. Really wild. One idea was for a tiny, walking robot not
much larger than an ant. (``Basically a silicon chip with legs,'' Fearing said.)
Another idea was for a hopping robot modeled after an octopus. And then there
was robofly.
The Navy loved robofly. It also loved robolobster, now being
built at Northeastern University, and robopike, which swims in a tank at the
Massachusetts Institute of Technology.
The robomenagerie is the vanguard of biomimetics, a strange
field where scientists reverse-engineer nature's greatest tricks.
``There are all kinds of things nature can do that we don't
know how to do yet,'' Fearing said.
The idea is to copy Mother Nature's nifty tricks -- things
like a lobster's ability to navigate pounding surf or a bat's sonar that allows
it to find mosquitoes in the dark.
The pint-size, or, in the case of robolobster, quart-size,
robots also represent a move among engineers and researchers toward
microrobotics.
The idea is to use a bunch of little robots to do the work of
one big robot -- or human. The Defense Department likes the idea of sending
robobeasts to do things far too dangerous for humans -- nasty little tasks like
clearing land mines or inspecting nuclear reactors in submarines. Robot, after
all, comes from the Czech word robota, which means drudgery.
The best example of the microrobotic trend is NASA, which has
embraced the ``smaller, faster, cheaper'' philosophy of sending lots of little
space probes to do the work of one big space probe.
With a single big robot, it's ``one giant accident, and you're
hosed,'' Dickinson said. ``But if you throw up 1,000 little robots and lose a
few of them, or even half of them, you'll still be getting a lot of
information.''
While Fearing has been fascinated with robots since high
school, Dickinson is new to the game. He was drafted by the team because of his
expertise in the arcane field of insect aerodynamics but admits he likes the
idea of tinkering with a robot.
``A lot of biologists,'' he joked, ``are nerdy geeks who, but
for a twist of fate, would have been engineers.''
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