Design and Evaluation of Fabric Cooling Channels for Twisted Coiled Actuators
Abstract
Twisted coiled actuators (TCAs) are biomimetic and inexpensive artificial muscles. To enable their integration into soft robotics, a novel cooling apparatus was designed, consisting of a fabric channel to house the TCA and a miniature air pump for forced convection. The channel was designed to be lightweight, flexible, and easy to integrate into a soft wearable robotic device. The effect that the channel dimensions had on TCA performance (cooling time, heating time, and stroke) was investigated by testing combinations of three widths (6, 8, and 10 mm) and three heights (4, 6, and 8 mm). In general, as the channel dimensions increased, the cooling time and heating time decreased, however the stroke was unaffected (provided that the channel height was above 4 mm). The largest channel, 10 mm width and 8 mm height, resulted in the best combination of cooling time, heating time, and stroke, and thus it was used in a secondary experiment to compare the performance of the TCA with and without the cooling apparatus. When compared to passive cooling without a channel, the cooling apparatus resulted in a 42% decrease in cooling time (21.71 ± 1.24 s vs. 12.54 ± 2.31 s), 9% increase in the heating time (3.46 ± 0.71 s vs. 3.76 ± 0.71 s), and a 28% decrease in stroke (5.40 ± 0.44 mm vs. 3.89 ± 0.77 mm). This work demonstrates that fabric cooling channels are a viable option for cooling TCAs. Future work can continue to improve the channel design and investigate alternative means of air flow to further improve the performance of the TCA.