LAUSR

A key issue with wearable technology today is the popular use of stiff electrical motors to actuate the joints. Although their performance is ideal in terms of power, bandwidth, accuracy, and speed, they do not have the inherent ability to replicate many key biological properties. This includes the ability to modulate compliance, produce linear actuation, and provide high power-to-weight ratios. The solutions to replicating these properties usually include complex mechanisms in the form of gear boxes, parallel spring mechanisms, and control algorithms, making these devices costly, heavy, and large. As an alternative, the twisted coiled actuator (TCA) is flexible, soft, and can provide large strain and high power outputs when thermally activated. This article provides a new solution to modeling the thermal behavior of TCAs within an active air cooled enclosure. The thermal models were validated against multiple inner tube diameters, heating powers, cooling pressures, and TCA sizes, and predicted the temperature to within 8.16 $^\circ \text{C}$ during heating, and 4.33 $^\circ \text{C}$ during cooling, corresponding to 92.7% and 94.5% accuracy, respectively. After model validation, the sensitivity of the input design parameters to performance characteristics, such as system bandwidth and efficiency, were investigated to provide specific use cases on model optimization techniques.