Long, Fibrous, and Tailorable Dielectric Elastomer Artificial Muscles via Mask-Free Stamping of Carbon Nanotube Electrodes

Abstract

High-performance, large-size artificial muscles are in great demand in the field of robotics. This work reports a comprehensive approach for fabricating, actuating, sensing, and controlling a 180 mm-long fibrous dielectric elastomer (DE) artificial muscle. The fabrication process introduces a novel method for patterning large-area, uniform electrodes using vacuum filtration followed by mask-free stamping on DE substrates. To address the challenge of long charging times that impair dynamic performance, an amplitude modulation algorithm is developed for high-frequency actuation, which increased generated strain by 64% at a resonant frequency of 10 Hz. Additionally, the hollow space within the rolled artificial muscle is used to integrate a waveguide that serves as a strain sensor. This combined actuation-sensing structure maintains flexibility and actuation capabilities while enabling self-sensing and feedback control. The versatility of the DE artificial muscle is further demonstrated by segmenting a single long muscle into three shorter units and employing these units to construct two multi-actuator machines: a tensegrity-based gimbal and a rotary engine. This work advances the large-scale production and application of DE artificial muscles.