Browsing by Subject "wearable technology"

Now showing 1 - 5 of 5
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    Bear Hug: The Design and Development of an Active Deep Touch Pressure Garment for Sensory Processing Disorder
    (2017-08) Duvall, Julia
    Many medical conditions, including sensory processing disorder (SPD), employ compression therapy as a form of treatment. SPD patients often wear weighted or elastic vests to produce compression, deep touch pressure (DTP), on the body, which have been shown to have a calming effect on the wearer. Unfortunately, current products (weighted vests and blankets, pneumatic garments, and negative ease stretch garments) are unable to meet their wearers’ needs, in that they are unable to both provide the dynamic compression required, while also meeting the user’s comfort needs by being unobtrusive. Recent advances in compression garment technology incorporate active materials to produce dynamic, low bulk compression garments that can be remotely controlled. The purpose of this thesis is twofold, first, to identify requirements for a DTP therapy garment, and second, to a build a dynamic garment for DTP therapy. A literature review, a qualitative investigation with experts and occupational therapists, and a quantitative study of current DTP garments were used to build a problem variable framework for a more optimal DTP therapy garment. The variables that were identified fell into two major categories; system variables, which encompass the basic important features needed in order to provide DTP on the body, and usability variables, which are the other important features required for an effective and efficient system. Following this investigation, an active compression vest using shape memory alloy (SMA) spring actuators was developed in order to better meet these requirements than existing DTP products. The vest prototype incorporates 16 SMA spring actuators (1.25 mm diameter, spring index = 3) that constrict when heated, producing large forces and displacements that can be controlled via an applied current. When power is applied (up to 43.8 W), the prototype vest generates increasing magnitudes of pressure (up to 37.6 mmHg, spatially averaged across the front of the torso) on a representative child-sized form. Average pressure generated was measured up to 71.6% of the modeled pressure, and spatial pressure non-uniformities were observed that can be traced to specific garment architectural features. Although there are no consistent standards in magnitude of applied force in compression therapy garments, it is clear from comparative benchmarks that the compression produced by this garment exceeds the demands of the target application. Additionally, the garment can produce a dynamic and controllable pressure durations and magnitudes within a low and unobtrusive form factor, which are identified as important requirements for DTP therapy. There are several variables that require further investigation, including thermal comfort of the garment. This study demonstrates the viability of SMA-based compression garments as an enabling technology for individualized and enhanced SPD (and other compression-based) treatment. Additionally, the technology can be used as a tool to determine and standardize optimal treatment parameters.
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    Characterizing the Influence of the Textile-Sensor Interface on Stitched Sensor Performance
    (2019-07) Dupler, Ellen
    Textile-based strain sensors are first defined with examples of various sensing mechanisms and applications, focusing on on-body smart garments for biomonitoring. A current lack of research in the textile substrate influence on sensor performance is noted, with a thesis investigation outlined to highlight key variables that may be important for successful sensor design. Two conductive thread stitch-based strain sensors are chosen for the textile-based strain sensors and two fabric substrates (2-way and 4-way stretch) are used to investigate their influence on sensor performance. Part 1 investigates if fabric strain properties change due to the attachment of sensors and how the sensor performance changes due to fabric choice and attachment angle. Part 2 uses the recommendations for textile choice, stitch geometry of the sensor, and sensor placement based on Part 1 results to create a 3-sensor, 60° strain rosette. Between the two versions of rosettes fabricated, the 4-way fabric and chainstitch geometry, the strain rosette is proven to improve the overall sensor performance in predicting force, displacement, and force direction. This rosette is characterized and using machine learning model algorithms, model-fitted for future garment based strain sensing applications.
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    Development of Form-Fitted Body-Worn Force Sensors for Space and Terrestrial Applications
    (2016-12) Berglund, Mary Ellen
    Sensing force on the body is useful in the design of many on-body systems, including gas-pressurized space suits, for design diagnostics (e.g., determining where an on-body system is exerting potentially dangerous amounts of force) and for in-use monitoring. Mechanical Counter-Pressure (MCP) space suits have advantages over gas suits, and are an example of where measuring on-body force would be necessary. The development of an unobtrusive and practical means of measuring force in an MCP suit has yet to be established. Reasons for the absence of an established method for force-sensing within an MCP suit lie in the difficulties associated with integrating a force sensor, unobtrusively, into the under-layers of the user’s garment. If the sensor introduces pressure points (e.g., is rigid or bulky), it will potentially cause harm to the user. This thesis describes the process of developing a soft and unobtrusive force sensor that avoids the use of a stiff apparatus. Specifically, the criteria for sensor selection and initial characterization of a variety of candidate sensor configurations when exposed to an applied load will be discussed. This thesis focuses on three experiments that were performed. The first experiment featured a commercial piezoresistive flex sensor as well as a custom coverstitched stretch sensor that were adapted to respond to normal forces and evaluated in a laboratory compression test. The flex sensor response displayed considerable noise, particularly evident in recovery artifacts when the load was fully removed from the sensor. The coverstitch sensor, on the other hand, had a more consistent, linear response in relation to the load being applied. Based on the findings and analysis of the first test, a second experiment was performed to examine the accuracy and performance of different lengths and widths of the coverstitched stretch sensor. The findings concluded that the thin 2’’ coverstitched sensor displayed the most promising results in terms of overall correlation with applied load and standard deviation between trials in relation to the other coverstitched samples that were tested. The final experiment extended the findings from the second experiment to test two different support structure substrates, rubber and silicone, each implemented in a topography of small hemispheres in varying size (small-diameter hemispheres, medium-diameter hemispheres, large-diameter hemispheres, and a flat topography). The results of the third experiment showed promise for the flat topography, which exhibited the strongest correlation between sensor response and applied load for both elastomer rubber and silicone substrate materials. Results were less favorable for the more extreme large-diameter hemisphere topography, which exhibited a weaker correlation indicating the larger the diameter the hemisphere was in the substrate material, the weaker the correlation between the load being applied to the sensor that was overlaid on the substrate material and the sensor’s response (resistance readings). The development of an unobtrusive, form-fitted stretch sensor that measures force is a significant step forward for MCP suit design and controllability, as well as for many other domains in which sensing forces on the body is important. The results of this thesis study illustrate the difficulties associated with implementing a flex sensor onto a pliable surface. Additionally, this thesis study illustrates the potential that the coverstitched stretch sensor has for force-sensing applications.
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    Dynamic Compression for Novel Haptic Interactions
    (2020-12) Foo, Esther
    The sense of touch is an integral part of our everyday experiences. This research examines one of the ubiquitous touch sensations—compression, as a novel interface and mode of interaction. Specifically, it seeks to answer questions related to how people experience compression stimulus given varying compression inputs, applications and contexts. This work first investigates user perception of on-body compression, broadly, from an experience standpoint, including the consideration of parameters (varying compression intensity, duration, pattern, location) and confounds that influence user experience. In order to understand, evaluate, and deploy garment-based compression, however, advancements in wearable technology were required. Therefore, a portion of this work was also dedicated to the design and development of novel compression garment technologies. Taking a human-centered and iterative design approach, soft, garment-based compression technologies driven by shape memory alloy (SMA) actuation—a type of soft robotic actuator—were developed. The second half of this research builds upon the initial findings and examines application-specific cases of such compression technologies, with particular focus on its use in communicating and modulating emotions. The first application on the communication of emotions was motivated by the close relationship between social touch and emotions. Through two online surveys, this research characterized user expectations in selecting strategies of various intensities and patterns on different body locations for emotional communication through warm, compressive actuation (as afforded by the SMA garment), while delimiting/categorizing the range of mental models used during the process. The second application area involves the use of compression for affect modulation. Through a mindful meditation study augmented with compressive haptics delivered through the SMA-based garment, the potential of using compression to promote focused attention and facilitate an overall, positive meditation experience for novice practitioners was demonstrated. Ultimately, the results of this research give rise to new opportunities in a variety of applications and provide a roadmap for interface/interaction design in those context, including enabling new modes of interaction between users separated by distance (e.g., tele-rehabilitation, social mediated touch) as well as new haptic sensations in the area of immersive experiences (e.g., media augmentation, virtual reality).
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    Is There a Color to Context?: Exploring Domain Associations in Wearable Technology
    (2019-08) Gagliardi, Nika
    Studies have found significant impact of domain, or context-of-use, on the social acceptance of wearable technology (Bodine & Gemperle, 2003; Herath et al., 2011; Van Heek, Schaar, Trevisan, Bosowski, & Ziefle, 2014). Therefore, factors which influence domain perceptions are relevant to wearables research. Correspondingly, anecdotal evidence has pointed to the influence of color (e.g. color associations) on wearable technology domain perceptions (Häkkilä, Vahabpour, Colley, Väyrynen, & Koskela, 2015; Starner, Rhodes, Weaver, & Pentland, 1999), yet thorough investigation and empirical evidence of these findings is lacking in the literature. For these reasons, the purpose of this study was to investigate the influence of color and body-worn form on wearable technology domain and function observations. This study used a mixed methods approach to assess the perceived domains of different colored wearable technology products by third party (limited information) observers. Six different products (three arm-worn and three face/head worn) were pilot tested, ultimately leading to the presentation of an armband, eyewear, and headband product in ten different colors. One of each product was randomly selected and presented to 1,413 (131 to 151 per product) non-colorblind Millennial age Mechanical Turk Workers, 522 of which also answered additional, open-ended questions to probe their selection answers. Participants were asked to assess the different colored stimuli and select the domain(s) in which, in their opinion, the product most likely belonged. T-tests were used to compare the counts of domain selections. Open-ended questions asked participants to first name what they believed the device to be and do, then describe if and why the product was recognized, and finally, to comment on the recognizability of the term wearable technology and its relationship to the presented stimuli. The clearest and most dominant results were found in the observed influence of product form and body location on perceived domain: Within each product (across colors), there were consistently observed product domain selections, and in open-ended responses there were consistently referenced products and guessed functions. Consistent domain selections regardless of color were seen in both highly recognized products (e.g. armband) and unrecognized products (e.g. headband). Conjointly, there were similar domain selections between comparable product types (e.g. Gaming & Entertainment in smart glasses and in an HMD) and between comparable body locations (e.g. Health & Wellness in arm-worn products). Other information offered by participants in the product discernment process were possible users and use-case scenarios. This study did not find strong, conclusive results that color significantly altered domain perceptions of unidentified products. Certain trends indicated that color had some influence in domain selection. For example, Medical ratings were consistently high when the product color was beige—however, results and count were not often significant. While color may have been a feature utilized in perception, its influence was not dominant; results primarily point to dominant product and body location function associations, in the minds of American Millennials, and highlight the salient interrelationship of both in product discernment. The results and supporting open-ended responses also speak to what is perceived as common—and potentially acceptable. Finally, the results of this study point to the need for more research on color associations and color influence in wearable technology perception. Study limitations are discussed in depth, and suggestions for future research are described.