Will Artificial Muscle Make You Stronger?

Three clean-cut engineering students from Virginia Tech—Steve Deso, Stephen Ros and Noah Papas—worked evenings and weekends in the lab for months to build their robotic arm as part of a project required to graduate.“We wasted our entire senior year—no partying,” Deso says, and the others laugh. They had spent three years in class learning about Newtonian mechanics, solid mechanics and biomechanics, and hanging out together in their spare time.“We were looking for something that would apply our skills,” Ros says. They spotted an online article about the contest and joked about entering. It seemed too big a project at first, Deso recalls. They e-mailed Bar-Cohen.“He said, â€Just go for it,´” and they did.
The three decided to use an artificial muscle called polyacrylonitrile, a gel imbued with fibers for strength. After burning through their $800 budget, they begged, pleaded, and scrounged parts and help. Unable to afford polyacrylonitrile, they synthesized it, starting with textile fibers donated by the manufacturer, Mitsubishi Rayon. A prosthetics company donated a metal elbow for the arm, and a body shop spray-painted it for no cost in maroon and orange, their school colors.

Papas pulls one of their muscles from a plastic bag to show me. It´s about a foot long and three quarters of an inch thick, brown and moist; it feels like a piece of raw meat and resembles a giant slug. For the match, they´ll place it inside Plexiglas and use a windshield-wiper pump to spray acid on it. They´ll tie the ends of the muscle to the arm with 50-pound-test fishing line so that it can wrestle. If all goes well, the acid will penetrate the gel, neutralizing charged groups in the plastic and forcing the material to contract. The students know their muscle is strong enough to perform, but they haven´t had time to test their final configuration.

When the match is over, they´re heading to Vegas.

The Swiss engineers clamp their arm to the table. They connect red and black leads from the box to a bank of power sources, and Felsen dons a heavy rubber glove for safety. Bar-Cohen walks to the table, microphone in hand, and booms, “It doesn´t look like an arm, it doesn´t feel like an arm, but it is an arm!” On three, the black box emits a low hum and the scent of burning rubber. Taking pointers from the champ, Felsen uses her body this time—and downs the arm in four seconds. The audience laughs. The Swiss team, which hadn´t had the chance to fully test their creation, looks on, stone-faced.“I thought we couldn´t lose,” Kessler would later tell me.

Now it´s the Virginia Tech team´s turn. The students, dressed in crisp-looking maroon polo shirts, clamp their
project to the table.“Now it gets exciting,” Bar-Cohen booms. He hands the microphone to Deso, who tells the crowd how they´re going to activate their device by adding acid. Felsen dons safety goggles and grips the hand. She pushes, and in three seconds the arm flops to the table without even a hint of resistance. A few moments afterward, inside the Plexiglas contraption, the sluglike artificial muscle begins to contract.

“Our goal was just to get here,” Deso tells me.“That was a huge accomplishment.” And they do seem happy. Only Ros voices a regret—that they didn´t activate their muscle earlier:“If [the match] had started five seconds later, we could have put up a fight.”