Biomedical Engineering Reference
In-Depth Information
Figure 10.13
An artistic interpretation of the Grand Challenge for the development of EAP-actuated robotics.
2001). Success in developing such an arm will lead to the possible use of EAP to replace damaged
human muscles, that is making ''bionic human.'' A remarkable contribution of the EAP field would
be to see, one day, a handicapped person jogging to the grocery store using this technology.
A graphic rendering of this challenge that was posed by the author is illustrated in Figure 10.13.
The intent of posing this challenge was to use the human arm as a baseline for the implementation
of the advances in the development of EAP materials. Success in wrestling against humans will
enable biomimetic capabilities that are currently considered impossible. It would allow applying
EAP materials to improve many aspects of our life where some of the possibilities include smart
implants and prosthetics (also known as cyborgs), active clothing (de Rossi et al., 1997), realistic
biologically inspired robots as well as fabricating products with unmatched capabilities. Recent
advances in understanding the behavior of EAP materials and the improvement of their efficiency
led to the historical first competition held in March 2005. In this competition, three robotic arms
participated and the human opponent was a 17-year-old female student. The three arms were made
by Environmental Robots Incorporated (ERI), New Mexico; Swiss Federal Laboratories for
Materials Testing and Research, EMPA, Dubendorf, Switzerland; and three senior students from
the Engineering Science and Mechanics Department, Virginia Tech.
1.
The arm that was made by Environmental Robots Incorporated (ERI), New Mexico held for 26 sec
against the 17-year-old student. This wrestling arm (see Figure 10.14) had the size of an average
human arm and it was made of polypropylene and Derlin. This arm was driven by two groups of
artificial muscle. One group consisted of dielectric elastomeric resilient type that was used to
maintain an equilibrium force and the other was composed of ionic polymer-metal composites
(IPMC) type strips that flex to increase or decrease the main resilient force.
2.
The Materials Testing and Research, EMPA, Dubendorf, Switzerland, arm (see Figure 10.15) held
for 4 sec before losing. This arm was driven by the dielectric elastomer type using multi-layered
scrolled actuators that were organized in four groups. A photo of one of the group lifting two
5-gallon water containers (about 20-kg) is shown in Figure 10.16. Using electronic control, these
actuators were operated similar to human muscles, where two of these groups acted as protagonists
and the other two operated as antagonists. The arm had an outer shell made of fiberglass that was
used as a shield for the electric section. The arm structure was made of composite sandwich
consisting of fiberglass and carbon fibers.
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