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NIST Advanced
Technology Program Announces Two Awards
05 Jan 2005
Work Could Lead to Advanced
Limbs for Amputees, Robots
Researchers at the NanoTech Institute at The University of Texas at Dallas
(UTD) have been awarded a $750,000, 20-month grant to develop artificial
muscles that convert chemical energy to mechanical energy. The award was
made by the United States Defense Advanced Research Projects Agency (DARPA),
whose charter is to develop new technologies for military applications.
UTD NanoTech Institute
researchers have long pioneered in inventing artificial muscles that
are electrically powered, and their discoveries in this area have led
to industrial commercialization efforts in the United States, Japan
and Sweden. This new program is more ambitious – to make artificial
muscles that are chemically powered, like natural muscle, and exceed
the force generation, contraction and speed of their natural
counterpart.
Electrically powered artificial muscles based on conducting polymer
and carbon nanotubes were first described by the principal
investigator of this new program, Dr. Ray H. Baughman, Robert A. Welch
Professor of Chemistry and director of the UTD NanoTech Institute.
Carbon nanotubes are nanosize cylinders of graphite sheets and
conducting polymers are plastics made “metallic” by doping. Dr. Alan
MacDiarmid, James Von Ehr Distinguished Chair in Science and
Technology at UTD and a winner of the Nobel Prize for the co-discovery
of conducting polymers, has made pioneering advances in developing
conducting polymer artificial muscles.
While the carbon nanotube muscles can exceed the performance of
natural muscle by generating a hundred times the force and elongating
twice as fast, the contraction is less than one-tenth that of natural
muscle. The conducting polymer muscles provide similar contractions to
natural muscles, but have neither high cycle life nor high energy
conversion efficiencies. The goal of the DARPA-funded program is to
eliminate these problems and convert from electrically powered to
chemically powered artificial muscles.
The proposed fuel-powered artificial muscles are at the same time fuel
cells, supercapacitors and mechanical actuators, so the same elements
convert a high energy density fuel to electrical energy, store this
energy and use it to do mechanical work. These artificial muscles will
use strong, tough carbon nanotube yarns that were recently described
in the prestigious journal Science by UTD researchers and a colleague
from an Australian national laboratory.
“An important possible eventual application of this research is
artificial limbs that function like natural arms and legs – including
the ability to move and manipulate objects -- both for amputees and
robots,” Baughman said. “While we are very far from achieving this
vision at present, we have already experimentally demonstrated
primitive devices that directly convert the chemical energy of fuels
to mechanical motion.”
The first “fuel cell artificial muscle” was demonstrated at UTD by
Research Scientist Von Howard Ebron, Research Associate Zhiwei Yang
and Dr. John Ferraris, interim dean of the university’s School of
Natural Sciences and Mathematics.
Source: University of Texas at Dallas
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