PROCEEDINGS ARTICLE | July 27, 2004
Proc. SPIE. 5385, Smart Structures and Materials 2004: Electroactive Polymer Actuators and Devices (EAPAD)
KEYWORDS: Actuators, Modulation, Sensors, Polymers, Dielectrics, Gait analysis, Electroactive polymers, Artificial muscles, Polymeric actuators, Mode conditioning cables
The rehabilitation community is at the threshold of a new age in which orthotic and prosthetic devices will no longer be
separate, lifeless mechanisms, but intimate extensions of the human body-structurally, neurologically, and
dynamically. In this paper we discuss scientific and technological advances that promise to accelerate the merging of body and machine, including the development of actuator technologies that behave like muscle and control
methodologies that exploit principles of biological movement. We present a state-of-the-art device for leg rehabilitation: a powered ankle-foot orthosis for stroke, cerebral palsy, or multiple sclerosis patients. The device employs a forcecontrollable actuator and a biomimetic control scheme that automatically modulates ankle impedance and motive torque to satisfy patient-specific gait requirements. Although the device has some clinical benefits, problems still remain. The force-controllable actuator comprises an electric motor and a mechanical transmission, resulting in a heavy, bulky, and noisy mechanism. As a resolution of this difficulty, we argue that electroactive polymer-based artificial muscle technologies may offer considerable advantages to the physically challenged, allowing for joint impedance and motive force controllability, noise-free operation, and anthropomorphic device morphologies.
