  For many years, the idea of a human with bionic muscles immediately conjures
up science fiction images of a TV series superhuman character that was
implanted with bionic muscles and portrayed with strength and speed far
superior to any normal human. As fantastic as this idea may seem, recent
developments in electroactive polymers (EAP) may one day make such bionics
possible. Polymers that exhibit large displacement in response to stimulation
that is other than electrical signal were known for many years. Initially, EAP
received relatively little attention due to their limited actuation capability.
However, in the recent years, the view of the EAP materials has changed due to
the introduction of effective new materials that significantly surpassed the
capability of the widely used piezoelectric polymer, PVDF. As this technology
continues to evolve, novel mechanisms that are biologically inspired are
expected to emerge. EAP materials can potentially provide actuation with
lifelike response and more flexible configurations. While further improvements
in performance and robustness are still needed, there already have been several
reported successes. In recognition of the need for cooperation in this
multidisciplinary field, the author initiated and organized a series of
international forums that are leading to a growing number of research and
development projects and to great advances in the field. In 1999, he challenged
the worldwide science and engineering community of EAP experts to develop a
robotic arm that is actuated by artificial muscles to win a wrestling match
against a human opponent. In this paper, the field of EAP as artificial muscles
will be reviewed covering the state of the art, the challenges and the vision
for the progress in future years.
