Advances in Artificial Muscles Using Plastic

pinglej writes "According to this story on MSNBC, Scientists at SRI have made some advances in muscles made using strained plastic that are more responsive than natural muscles. Has lots of neat applications from speakers to artificial limbs. " I think the best idea is to make me the strongest man alive - it'll be better than cybernetic body armor!

Comments

Applications

[Captn Pepe]

Materials like this exert force because they try to maintain an approximately uniform density, so an electric potential squeezes it into a different shape. The trouble with using this to do mechanical work -- like the "artificial muscle" this is being hyped as -- is that you can't exert very much force before the material starts to compress, or else you overwhelm the electrostatic forces. This is sort of the converse of the problem that piezo-based transducers have always had: the electrostatic potentials cause the crystalline lattice of a piezo to expand with considerable force ... but only for a few hundreds of microns, at best. Which makes them good for speakers, or ultra-fine positioning, but not so good for doing work.

As far as I can tell, the most promising avenue for these materials would be to use them rather like small, agile hydrolic pumps that have large dynamic range but little pushing power and even less pull. The comment in the article about an artificial butterfly could be insightful with respect to what you could do with these. As far as artificial limbs go, unless they can dramatically increase the force they can put out, they might be a major breakthrough for actuating the fingers of a prosthetic hand, but they'll be no good at all for replacing the wrist flexors, never mind a bicep.

I would suggest that researchers look for a way to turn this effect around, allowing the material to pull rather than push. Such plastics almost invariably have greater tensile strength than resistance to compression, and it's much easier to engineer around, too.