This research focuses on the development and validation of novel flexible wearable sensors that can be integrated into clothing and footwear for human motion analysis. The extremely high cost and complexity of instrumented treadmills and motion capture cameras make them prohibitive for large scale use. Additionally, the motion data of the patient/subject can be monitored for a limited amount of time and not in their natural work/home environment. As a result, a critical need exists for low-cost, comfortable wearable technology for human motion analysis.<br/> <br/>The sensing approach for the development of wearable sensors is based on the electrically conductive nanocomposite films of functionalized carbon nanotubes (CNTs) which are deposited using electrophoretic deposition. The thickness of the films is in the range of 150-750 nm and can be controlled by varying the process parameters. The nanocomposite film is chemically bonded to the fiber surface and shows piezoresistive electrical/mechanical coupling. A variety of common fabrics such as polyester, nylon, wool, aramid and cotton can be coated.<br/> <br/>The pressure sensors have the ability to detect an extremely wide range of pressures from tactile to bodyweight to thousands of pounds, and a large change in the in-plane electrical conductivity is observed on application of pressure. Preliminary experiments for the use of these sensors for gait analysis have been conducted by integrating these sensors into footwear with subjects walking on a split-belt treadmill instrumented with force sensors. For joint motion detection, the CNT based sensors are integrated into wearable sleeves. When integrated into an elbow sleeve, the sensors show a dramatic 3,000% change in resistance upon elbow flexion, demonstrating ultra-high sensitivity. These fabric based sensors have the potential to be used for biomechanics research, human-machine interaction, feedback control for assistive devices and rehabilitation related clinical applications.

Flexible and wearable sensors for human motion analysis

2019 Fall National Meeting

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