Robotics Update

Hydrogen could be used to make robot muscles far quieter than compressed air or electric motors:

http://www.newscientist.com/article/mg20427305.600-hydrogen-muscle-silences-the-domestic-robot.html

Robotics Update

New nanotube-based material could form the basis of robotic muscles that function similar to biological muscles only with far greater capability (once they increase the density):

http://www.newscientist.com/article/dn16806-robots-could-flex-muscles-that-are-stronger-than-steel.html

"Baughman and colleagues have developed a technique to make ribbons of tangled 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 tangled nanotubes are constructed into a film that can be described as an aerogel, meaning it contains more air than anything else. Each cubic centimetre weighs only 1.5 milligrams and, given the film's thinness, a single gram would cover 30 square metres."

"It is extremely stiff and strong in the "long" direction – that in which the nanotubes are aligned – but is as stretchy as rubber across its width. It also maintains its properties over an extreme range of temperatures: from -196 °C, at which temperature nitrogen is liquid, to 1538 °C, above the melting point of iron."