The
off-road robo-roach
By Andrea Baird
Anyone
who has ever chased a cockroach through the kitchen with a rolled-up
magazine has seen what incredible movers they are. A cockroach
can dash across the linoleum, up the cabinet door, over this morning’s
butter knife and breakfast plate, down the wall, and under the
refrigerator before a thrown shoe ever hits the counter. Few people
appreciate such speed and agility in their household pests, but
robotics engineers know a good design when they see one. “If
you had a robot that could do half the things a cockroach can
do,” says Roy Ritzmann, a biology professor at Case Western
Reserve University, “you’d have the best legged robot
in the world.”
Traditionally, if engineers
have wanted a robot to move they’ve used that quintessential
human invention: the wheel. On a flat surface, (such as that other
great human invention: the road) wheels work wonderfully. To make
robots that can go off road, however, engineers are turning to
the leg, nature’s invention for moving animals in any environment.
In the near future, engineers hope legged robots will explore
places too bumpy and obstructed for wheels and too dangerous for
people—like the rubble of fallen buildings, unmapped minefields
or (way off-road) the boulder-strewn surface of Mars. As the model
for this new frontline of robotic rescue workers, soldiers and
astronauts, many engineers have chosen that nimble legged runner,
the cockroach.
To make a robot as agile
as a roach, scientists first have to figure out why roaches are
so nimble. To unlock this secret, biologists put cockroaches through
rigorous road testing. In his University of California, Berkeley
lab, one such scientist, Robert Full, videotapes the insects running
on roach-sized treadmills and over uneven ground to see how their
legs move. He glues little jetpacks to their backs to discover
what they do when a blast of air gives them a push in mid-stride.
(One of the advantages of working with roaches is that no one
really cares what you do to them, says Roger Quinn, professor
of mechanical engineering at Case Western Reserve University:
“PETA has not been banging down the door.”) Video
of roaches racing across blocks of Jell-O reveals how much force
each foot exerts on the ground as the animals run. (A tip for
the at-home biologist: Full quickly discovered that it’s
best to use unflavored Jell-O to study running rather than eating
behavior).
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