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).