Y-A Lin, K.J. Loh
University of California, San Diego,
Keywords: e-textile, fabric, human, kinesiology, sensor, strain, tape, thin film, tomography, wearable
Summary:Wearable sensors have attracted considerable interest among the general public due to increased awareness in personal health. Technologies as such can be particularly beneficial to industries related to virtual reality, sports performance, military, and healthcare. However, most wearable sensors today are still based on bulky, rigid, inconvenient, electronic devices. Furthermore, they are limited to discrete sensing at their instrumented locations. In addition, fabric-based sensors and electronic textiles, when worn, can undergo relative movement with respect to the skin during human movement and are thus subjected to skin artefacts. On the contrary, sensors in the form of patches are more conformable to the human body and are capable of distributed sensing. For this reason, the purpose of this study is to develop a comfortable, durable, self-adhesive, fabric-based, skin-strain sensor capable of continuous, real-time, human movement monitoring and assessment. The approach was to integrate strain-sensitive graphene-based thin films with commercially available self-adhesive, elastic, fabric as the substrate. The strain and motion sensing properties of these “Motion Tapes” were characterized using a load frame. Upon verifying their strain sensing, mechanical, and fatigue properties, these self-adhesive and skin-mounted wearable sensors were tested on individuals performing different activities and undergoing different types of movements. Data acquired from the Motion Tapes were compared against post-processed recorded video of subjects performing different controlled motions as well as optical motion capture. In addition, a network of these Motion Tapes could be applied to form a network of sensors for distributed motion monitoring and interrogated by electrical resistance tomography (ERT). In general, repeatable and consistent sensing responses were obtained and confirmed, which demonstrated their promise as a field-deployable wearable sensor for functional movement assessment and monitoring that is also at the cusp of commercialization.