A Humanoid Robot with Superhuman Strength? Soon, using Carbon Nanotube Muscles

Humanoid Robots have often been depicted in Hollywood with superhuman strength; the fembots in the Bionic Woman series from the 1970s are a classic example. A more recent one is found in the I-Robot (2004) Nestor Class 5 (NS-5) humanoid robot named Sonny. Sonny is an advanced robot that has enhanced armor plating and superhuman strength even greater than average NS-5 units, and is portrayed as astonishingly quick in a series of combat scenes throughout the film.

Researchers at the University of Texas, Dallas may bring us one step closer to making science fiction a reality. Ray Baughman, a materials scientist at the Alan G. MacDiarmid Nano Tech Institute says, “We’ve made a totally new type of artificial muscle that is able to provide performance characteristics that have not previously been obtained.”  According to a report in the New Scientist, Baughman and colleagues have developed a technique to make ribbons of carbon nanofiber – tangled carbon nanotubes that expand in width by 220% when a voltage is applied and then return to their normal size once it is removed. The process takes only milliseconds.

The potential of this new carbon nanotube muscle has wide-ranging applications in the field of robotics. Baughman points out that a collection of the carbon nanotube ribbons could function as artificial muscle fibers – for example, to move the limbs of a walking bipedal robot.  The carbon nanofiber can be formed into a thin super-tough film that is stronger than steel and stiffer than diamond, which expands dramatically when the voltage is applied.

[Video courtesy of Science Technology Education Media (STEM) University of Texas, Dallas]

Roboticists who have experimented with artificial muscle technology, such as air muscles or muscle-wire, are well aware of the design challenges in mimicking the speed and accuracy of human muscles and reflexes, and that these methods are less than ideal for a robotic artificial muscle. But the new carbon nanotube muscles hold considerable promise for revolutionizing the science and development of robotic muscles. Steve Rainwater at Robots.net breaks down the materials science implications of this new research while contrasting with more traditional approaches to building the perfect artificial muscle:

“Wouldn’t it be nice to have something better? Say, a material with a Poisson’s ratio of 15, a contraction rate of 30,000% per second, an elongation rate of 220% per second, the density of a gas, and a specific strength greater than steel. If that’s not enough for you, how about if this new muscle material could expand 4,000 times faster than human muscles and could be switched on and off up to 1,000 times per second, and functioned in temperatures ranging from -196C to +1538C?”

The research is formally described in a jointly-authored article appearing in the recent edition of “Science Magazine” entitled, “Giant-Stroke, Superelastic Carbon Nanotube Aerogel Muscles.”

Though the research is much in its infancy, carbon nanotube muscles have significant potential applications to the development of a synthetic brain. What is now apparent is that carbon nanotubes and carbon nanofiber will also play a major role in the development of a new robotic artificial muscle, which can be applied to the musculature of a humanoid robot. This would entail potentially significant applications in extreme or dangerous environments, where a humanoid robot will someday be employed—such as in combat zones, serving as security guards, policing the streets, or in other high risk jobs like fighting fires, conducting rescue operations, and mining.

While the NS-5s of the future won’t have the lightening speed that Hollywood depicts, it’s not unlikely that humanoid robots equipped with carbon nanotube muscles will display considerable, possibly superhuman strength and highly developed reflexes. It’s even plausible that a humanoid robot will be developed to compete against humans in athletic competitions. For example, the inspiration behind the annual RoboCup competition is to design humanoid robots that can beat the human world soccer champion team by the year 2050. But with such sophisticated musculature, it remains to be seen how humanoid robots and humans will fare in actual sports competitions. Imagine robotic professional wrestling and be aware! If machines are ever equipped with carbon nanotube muscles capable of expanding 4,000 times faster than human muscles and able to be switched on and off up to 1,000 times per second, as is currently speculated, then they may well launch their human counterparts right out of the ring!

Tags: artificial muscle, carbon nanofiber, carbon nanotube muscle, carbon nanotube muscles, future of robotics, humanoid robot, superhuman strength