The off-road robo-roach
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In the past, Roger Quinn and his robotics team at Case Western Reserve University have also worked with stylized cockroach robots like the Stanford and Michigan machines. For their newest project, however, they decided to take a new tack and mimic a cockroach’s structure as closely as possible.

Their robot, like the real thing, has jointed legs that are small and nimble in the front and long and powerful in the back. The legs, though 20 times bigger than a live roach’s and attached to a simple metal rod rather than a cockroach-like body, look disturbingly realistic and ready to run. Their appearance is misleading, however. The robot can’t move. The jointed legs are so complicated that the engineers are still designing their controls. But Quinn says that once the robot is mobile its joints will allow it to do things that simpler robots can’t, like stepping sideways to avoid an obstacle or change where it places its feet to stepping across a hole or over a slatted surface.

Though the robot can’t walk, it is mechanically stable. It can step in place in the tripod gate, and, if pushed, bounces back into place. The artificial air-controlled muscles that power the robot act as shock absorbers at every joint in the leg. The muscles consist of rubber tubing inside a woven metal tube that works like a stretched Chinese finger trap. When the rubber tube is filled with air, the metal tube widens and consequently shortens. By filling both halves of an opposing pair with a little air, each joint of the leg becomes a tuned spring working to balance the robot.

With these three robots, engineers have demonstrated that a legged robot can run stably—even over bumpy terrain—using basic, mechanical cockroach motion. But a robot that can run over rough ground in a blind, unending straight line is still not very useful (except, perhaps, in the minefield scenario). The next step for engineers is to give their robots sense organs like antennae, eyes, ears, and noses so they can avoid obstacles, and, most importantly, a brain that will allow them to complete their missions without a human at the helm.

Though the obstacles engineers face are formidable, Quinn projects that a fully autonomous off-road robot will be developed in the next five years.Five years beyond that, robotic cockroaches may be finding survivors in disaster wreckage, exploring the surfaces of distant planets,...