Browsing by Author "Berglund, Mary Ellen"
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Item Development and Characterization of a Mannequin-Based Method for Fit Measurement of Wearable Systems(48th International Conference on Environmental Systems, 2018-07-08) Compton, Crystal; Berglund, Mary Ellen; Chen, Jin; Brubaker, Derek; Bunyard, Clayton; Dunne, LucyMeasuring fit of a wearable system on a body is a perennial challenge in the development of all kinds of on-body systems including clothing and everyday products. For human spaceflight applications, aspects of fit that relate to contact between the body and the garment are especially important. Wearable sensors and electrodes are the most common approach to sensing this kind of functional fit, however, they also present challenges in the form of reduced accuracy when applied to soft, unpredictable body surfaces and observer effects as the sensor structure alters the distribution of force and contact over the skin. Augmented mannequins offer an alternative to human-based evaluation. While mannequins are more limited in anthropometric variability, they can provide a controlled testing environment in which fit variables can be better isolated prior to human testing. In previous work we have established an electrical method for measuring contact between the body and a worn garment. Here, we extend that concept through implementation using an augmented mannequin, which improves the efficiency of testing and allows body/garment contact to be more specifically characterized. Importantly, our approach maintains the continuous mechanical properties of the mannequin, designed to be similar to human tissue. This study presents the development and validation process for mannequin- and garment-integrated electrodes, as well as results of an initial pilot test measuring body contact over repeated donning/doffing of two garment and garment-electrode structures on the augmented mannequin.Item Development of Elastomer-Strain Gauge Composite for On-Body Dynamic Force Measurement(47th International Conference on Environmental Systems, 2017-07-16) Berglund, Mary Ellen; Foo, Esther; Dunne, Lucy; Holschuh, BradSensing force on the body is useful for a variety of aerospace applications. In extravehicular activity (EVA) suits, sensing force on the body is important to determine when and where a rigid suit structure comes into contact with the astronaut. In intravehicular activity (IVA) compression garments, real-time force sensing could help improve current garment performance, or even enable new forms of compression therapy. In this paper we describe the development of a novel elastomer-strain gauge composite designed to unobtrusively measure contact force on the body. The sensor, which combines a strain-sensitive conductive cover-stitched trace with a compliant elastomer matrix, is engineered to respond to normal force by inducing repeatable and predictable strain in the conductive trace. Consequently, the electrical resistance of the trace changes with applied force, leading to useful sensing capability. A parametric design study of two manufacturing methods and elastomer material stiffnesses (Shore value) was performed to assess the effects of these parameters on the elastomer-strain gauge composite performance. The two manufacturing methods differ in terms of ease of manufacturing. The results of this study indicated that the ‘direct-stitched’ manufacturing method with a lower Shore value had greater performance than the ‘layered-assembly’ manufacturing method in terms of sensor characteristics, evaluated based on polynomial model fitting and long term-repeatability. This type of novel elastomer-strain gauge composite enables unobtrusive on-body normal force sensing, which can benefit astronauts during IVA/EVA, as well as additional applications where on body force sensing is valuable.