Fit for Space: Leveraging a Novel Skin Contact Measurement Technique Toward a More Efficient Liquid Cooled Garment

Abstract

Comfort, mobility, and performance are all affected by the fit and contour of a garment to the body. Understanding the body-garment relationship allows for improvement of all of these aspects, and thus the garment and experience for the wearer. With current methods, it is possible to measure the body-garment relationship primarily in static positions, but mobile analysis is time- and equipment-intensive. A more direct garment contour and body contact monitoring procedure would benefit the functional clothing design community. Mobile measurement is especially important for functional garments, as the body-garment relationship changes over time during body movements. Here, we describe a new method developed to measure the body-garment relationship, specifically for mobile scenarios. This method detects body-garment contact using an electrical signal within a circuit formed between the garment and the body. The analog electrical connection (expressed as a varying voltage using a voltage-divider circuit) between the body and a conductive patch is processed and recorded by a microcontroller. In this investigation three main variables were evaluated for their influence on the measurement of body-garment contact: 1) patch materials, 2) applied force, and 3) patch sizes were tested within the body/garment interface. Material results showed that all of the tested materials (with the exception of one material, which contained the sparsest surface area of conductive material) facilitated a voltage response in the presence of body contact that could be viable for detecting contact between body and garment. However, preliminary tests revealed that materials with lower resistivity and more rigid structure facilitated a smoother signal with less noise, which correlated more closely with the input signal. Applied force results showed that the amount of force between the sensor and the body affects the response of the system. All patch sizes with the exception of the smallest size tested (0.3175 cm) were effective in measuring body-garment contact. The smallest diameter possible for the conductive patch is of interest, in an attempt to minimize its effect on the body-garment measuring system. A 0.635 cm diameter conductive hook fastener sensor was subsequently used to implement this method in a pilot evaluation of LCG (Liquid Cooling Garment) fit. A grid of six analog sensors (maximum amount for microcontroller used) was integrated into the right torso region of the LCG for testing. Various movements that would be similar to movements that astronauts would be performing in EVA were used to test body-garment contact. Results show distinct differences in body contact for each sensor during each movement.