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December 3, 2009
By John Trent
Kwang Kim, a professor of mechanical engineering in the College of Engineering, is at the forefront of research that could make robots run much more like they seem in movies and on television. That is, with very little noise.
Kim’s work with the building of artificial muscles that run on hydrogen, instead of much louder compressed-air pumps or electric motors, was featured recently in a news article in New Scientist.
The article notes that Kim “came up with the idea after realizing that hydrogen can be supplied silently by metal hydride compounds. Metal hydrides can undergo a process called reversible chemisorption, allowing them to store and release extra hydrogen held by weak chemical bonds. It’s this property that has led to the motor industry investigating metal hydrides as hydrogen ‘tanks’ for fuel cells.”
The article adds that Kim, and colleague Alexandra Vanderhoff first compressed “a copper and nickel-based hydride power into peanut-sized pellets. They then secured them in a reactor vessel and pumped in hydrogen to ‘charge’ the pellets with the gas. A heater coil surrounded the vessel, as heat breaks the weak chemical bonds and releases the stored hydrogen.” The vessel is then connected to artificial muscle, made of inflatable rubber tube and Kevlar. When two of these are placed on the sides of a robotic joint, the movement of muscles can be imitated by either inflation or deflation.
Kim says the muscle performs just as efficiently as those that run on compressed air.
“The system has biological muscle-like properties for humanoid robots that need high power, large limb strokes – and no noise,” Kim says.