Extraterrestrial

[SeriousMoney]

For Robots, Fuel Cells That Double as Muscles
By KENNETH CHANG, March 21, 2006
NewYorkTimes.com

An android walks into a bar... http://www.kurzweilai.net/news/frame.html?main=/news/news_single.html?id%3D5402

Ray H. Baughman, a professor of chemistry at the University of Texas at Dallas, has not built an android. He has not built a brain or an eye or a robotic equivalent of some other complex body part. Instead, he has built something that will also be crucial for future androids: artificial muscles.

Today's crude humanoid robots already use gears, pulleys and pistons to mimic the actions of muscles. But they are electrically powered, requiring that they be plugged in and tethered by an extension cord or powered by batteries, which drain quickly.

Dr. Baughman's advance, reported in the current issue of the journal Science, is that his new muscle fibers double as fuel cells. Just like real muscles, they power themselves instead of relying on external electrical power. Chemical energy also delivers a greater bang.

"The most advanced battery can only store only about one-thirtieth of the energy that is stored chemically in fuels such as methanol," Dr. Baughman said.

He and his colleagues have made two types of artificial muscles. One is a nickel-titanium alloy coated with platinum, which causes the fuel — currently methanol, but hydrogen or alcohol could work, too — to react with oxygen, producing heat. The metal shrinks; the muscle flexes. The artificial muscle can apply 100 times as much force as real muscle.

Dr. Baughman said the technology was simple enough that it could find commercial applications in as few as three years.

The second artificial muscle, currently less powerful, is made of a sheet of nanotubes, tiny but superstrong cylindrical molecules of carbon. The reaction of fuel and oxygen releases electrical charges that repel each other and cause the nanotube sheet to expand.

To put such artificial muscles into robots will require solving other problems, like how to control the amount of fuel going to the muscles. "The analogy of a circulatory system is really what's needed," Dr. Baughman said.

But for the future, he said, it is not entirely far-fetched for an android to walk into a bar.

http://www.nytimes.com/2006/03/21/science/21find.html?_r=1&pagewanted=print&oref=slogin