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Fabrication of Carbon-Based Ionic Electromechanically Active Soft Actuators
Published on: April 25, 2020
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Coil Formation and Biomimetic Performance Characterization of Twisted Coiled Polymer Artificial Muscles.
Nicholas S Witham1, Johannes Mersch2,3, Lukas Selzer4
1Department of Biomedical Engineering, University of Utah, Salt Lake City, 84112, USA.
Summary
Artificial muscles, or twisted coiled polymer actuators (TCPAs), demonstrate remarkable biomimetic performance, matching biological muscle capabilities statically. Further dynamic testing is needed to fully assess their potential in biomechatronic applications.
Area of Science:
- Materials Science
- Biomimetics
- Robotics
Background:
- Biological muscles exhibit complex, nonlinear force constraints based on state and history.
- Artificial muscles aim to replicate the full mechanical spectrum of biological muscles.
- Twisted coiled polymer actuators (TCPAs) are a promising class of artificial muscles.
Purpose of the Study:
- To mechanically characterize TCPAs using novel methods.
- To verify the biomimetic performance of TCPAs against biological muscle benchmarks.
- To establish comprehensive and reproducible test procedures for artificial muscle characterization.
Main Methods:
- Utilized a rheometer for high-precision mechanical characterization.
- Controlled and measured twist level, torque, length, force, and temperature during fabrication and testing.
- Formed TCPAs from linear low-density polyethylene (LLDPE) monofilament.
Main Results:
- LLDPE TCPAs generate stresses exceeding biological muscle across the strain spectrum.
- Achieved >40% contraction and >0.3 MPa stress at rest length.
- Demonstrated static biomimetic performance, withstanding 8 MPa tension without damage.
Conclusions:
- LLDPE TCPAs exhibit static mechanical performance comparable to biological muscle.
- Intelligent control systems can leverage TCPA mechanical properties for biomimetic actuation.
- High-throughput manufacturability positions TCPAs for advanced biomechatronic applications like prosthetics and exoskeletons.
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