US Defense Advanced Research Projects have assigned the University of Texas at Dallas to develop artificial muscles that convert chemical energy to mechanical energy. 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.

While the carbon nanotube muscles can exceed the performance of natural muscle by generating 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. 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.