Fabrication Parameters and Performance Relationship of Twisted and Coiled Polymer Muscles

Abstract

Twisted and Coiled Polymer (TCP) muscles are soft actuators made by inserting twist in a precursor fiber while attaching a dead weight at the end, followed by heat treatment. TCP muscles are thermally driven actuators with high power to weight ratio, large strain and low cost. These muscles have a wide variety of applications in engineering, specifically for robotics since these actuators have large linear deformation in response to applied power (Joule’s Effect). The performance of these muscles depend on numerous fabrication parameters such as speed of the coiling, dead weight used, precursor fiber type, number of filament in precursor fiber, number of plies and training cycles. An in-depth study of the fabrication parameters is required to understand the performance of the muscles. We have designed experimental setup to study the performance of the muscles on different input parameters such as load, current, voltage and output results such as displacement, force and temperature. We present the study of single, double and tripled plied muscles that are fabricated by plying together a twisted and coiled filament. Further, the power consumption of the muscles under various conditions is discussed. This study would help to establish a procedure to fabricate these materials with consistent properties.

Artificial stepper tensile actuator using Joule-heated twisted and coiled polymer muscles

“…Actuation principle of TCPM is demonstrated in different works [1,9,12,13,16]. One of the working principles of TCPM is based on simple phenomenon that relates to expansion or contraction of a twisted polymeric fiber in longitudinal or radial directions.…”

ModiFiber

“…Short actuators for experiments were fabricated using the method reported by Tadesse et al [24]. Throughout the paper, we utilized three types of precursory nylon threads to create our actuators; we will refer to them as "thin actuator" "thick actuator" and "fishing line actuator. "…”

Twisted and coiled polymer (TCP) muscles embedded in silicone elastomer for use in soft robot

“…2a) were fabricated, in batch 1 and 2. In batch 1, the muscles were then annealed by suspending 350 g dead weight and applying an increasing voltage proportional to the length of the TCP muscle using (*1.2 9 length of the muscle in inches (Sahran and Tadesse 2016;Saharan and Tadesse 2016) until the muscle reaches steady state. The muscles were then trained by applying a voltage equal to the last annealing voltage, 7 V, and suspending a weight of 200 g (Fig.…”

“…The muscle is made by twisting and coiling a precursor fiber and applying heat treatment (Sahran and Tadesse 2016), we called this material, Twisted and Coiled Polymer (TCP) muscle throughout in this paper. Silicone elastomer material (Ecoflex-30) is used as an artificial skin material due to its elasticity and other imperative features.…”