Benchmarking of a Commercially Available Stacked Dielectric Elastomer as an Alternative Actuator for Rehabilitation Robotic Exoskeletons

• Published in: 2019 IEEE 16th International Conference on Rehabilitation Robotics (ICORR) 2019-06, Vol.2019, p.499-505
• Main Authors: Behboodi, A., Lee, S.C.K.
• Format: Article
• Language: English
• Subjects: Actuators; Elastomers; Electrodes; Equipment Design; Exoskeleton Device; Exoskeletons; Force; Humans; Muscles; Rehabilitation - instrumentation; Rehabilitation robotics; Strain
• ISSN: 1945-7898; 1945-7901
• DOI: 10.1109/ICORR.2019.8779378

Recent commercial availability of a stacked dielectric elastomer actuator (SDEA) has opened up possibilities of their use as "artificial muscles" for rehabilitation robots and powered exoskeleton devices. Made by CTsystems, this actuator (CT_SDEA) is made from soft materials, and offers a lightweight and acoustically noiseless alternative to DC motor actuators used in conventional rehabilitation robotic systems. The purpose of the present work was to benchmark the electromechanical properties of CT-SDEAs to assess its capabilities and limitations for mechanizing rehabilitation robots. The CT-SDEAs tested in this study showed 21 ms electrometrical delay, and their calculated strain-rate was 660 %/s. They could generate 21.74 N of force and have a 426 W/kg power-to-mass ratio. Their longitudinal strain was measured at 3.3%. Additionally, their steady state current consumption was measured 39 \mu A. CT-SDEAs' fast response, short electromechanical delay and high strain-rate, make them highly suitable for closed-loop control. Additionally, their force generation capability, fast response, high power-to-mass ratio, and low steady state power consumption make them a strong candidates for exoskeleton applications. It's longitudinal strain (3.3%) however, was less than that of skeletal muscle (20%). Depending on the application, their use may require the addition of mechanical linkages, for force to displacement conversion.