Six years ago, Jet Propulsion Laboratory researcher Yoseph Bar-Cohen challenged scientists to create an artificial arm that could beat a human in an arm-wrestling match. The catch: The arm must be made of a pliable plastic material controlled by electrical impulses. In other words, no motors allowed.

Monday, in front of a battalion of TV cameras and an audience of hundreds, three groups of scientists took on Bar-Cohen’s challenge — and failed. One of the robot arms seemed to flop helplessly, while the other two quickly fell to a 17-year-old high-school student.

Even if they had worked, the devices wouldn’t have been ready for arm-wrestling competitions on ESPN: One relied on a potentially dangerous hydrochloric acid reaction, while another was powered by a strong electric current.

Nonetheless, Bar-Cohen still looked ecstatic after most of the media had left the International Society for Optical Engineering’s Smart Structures/NDE conference. He hadn’t expected anyone to take up his arm-wrestling dare for 20 years, and now one of the artificial arms managed to hold off the teenager for nearly a half-minute. “This is a major step,” he said. “But it’s a tough challenge.”

It could mean the transformation of robots from large, clunky, motor-driven devices — think of the robot arm that helped put together your car — into sleek, sturdy, self-contained machines. You know, like humans.

“There could be some point where you can have a robot dog, not walking like a machine, but walking like a dog,” said Bar-Cohen, a tireless advocate for the technology. “Or maybe a cheetah robot running on Mars instead of slowly rolling, climbing a mountain like we climb a mountain.”

Humans and animals, after all, don’t come with drive shafts and gears and wheels. Bar-Cohen and others expect that the artificial muscles will revolutionize prosthetics, allowing disabled people to more easily move their limbs.

More here.