Browsing by Author "Burch, Kaleb"
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Item Design and evaluation of wearable technology: sensing and assistance for human motion(University of Delaware, 2023) Burch, KalebBiomechanics research is at a crucial stage where researchers are seeking to translate results in the lab into results in the real world. However, most technologies that have been foundational to biomechanics research, such as optical motion capture systems, force plates, instrumented treadmills, and robotic exoskeletons, are restricted to use in the lab. In order to address this problem, biomechanists have sought to implement other approaches, one of the foremost being wearable technologies. The purpose of this dissertation was to develop wearable technology for measuring and assisting human motion outside of the lab. ☐ In Aim 1, we validated a novel insole pressure sensor for quantifying ground reaction force (GRF) during walking. We collected data from 7 participants walking on an instrumented treadmill while wearing the insole pressure sensor. This sensor was validated by quantifying agreement with gold-standard force plate measurements of peak GRF during walking at three different speeds. We found that this sensor could achieve moderate agreement with the force plate with a basic calibration procedure and a low-cost data acquisition system, which suggests potential to overcome the economic barrier to more widespread adoption of this technology. ☐ In Aim 2, we optimized cable-driven exosuit properties using musculoskeletal modeling and simulation. We recruited 5 healthy adult subjects to perform reaching, drinking, and hair-brushing motions, and used kinematics of these motions as inputs into a musculoskeletal model. We ran computed muscle control (CMC) simulations to first estimate unassisted muscle activity for these tasks, and then ran an optimization algorithm involving successive CMC simulations with different cable actuator properties. We used this optimization algorithm to identify optimal cable actuator attachment points and forces to minimize the combined activity of the middle and anterior deltoids. This method successfully identified optimal actuator properties that substantially reduced activity of the target muscles for all three motions. ☐ In Aim 3, we developed and tested a physical prototype of a shoulder exosuit for reaching and drinking assistance. In this study, we collected kinematic, EMG, and exosuit force data to evaluate how individuals altered motion in response to exosuit assistance. Subjects performed a series of reaches while not wearing the exosuit, while wearing the exosuit without assistance, and wearing the exosuit with assistance. In total, 200 reaches were performed with 120 reaches assisted by the exosuit to allow subjects to learn how to use the device. Subjects also performed drinking motions with and without powered assistance from the exosuit. We found that the exosuit successfully reduced muscle activity of the middle and posterior deltoids during reaching and drinking. Furthermore, we found that individuals altered kinematics in response to the exosuit by allowing their arms to follow exosuit assistance. Finally, we found that subjects exhibited trial-to-trial changes in movement duration and in the timing at which they used a switch to activate the exosuit. Future work should seek to evaluate the learning mechanisms behind changes in muscle activity and movement duration when using an exosuit and to integrate experimental results with musculoskeletal modeling and simulation to improve exosuit design.Item Estimating ground reaction force with novel carbon nanotube-based textile insole pressure sensors(Wearable Technologies, 2023-03-02) Burch, Kaleb; Doshi, Sagar; Chaudhari, Amit; Thostenson, Erik; Higginson, JillThis study presents a new wearable insole pressure sensor (IPS), composed of fabric coated in a carbon nanotube-based composite thin film, and validates its use for quantifying ground reaction forces (GRFs) during human walking. Healthy young adults (n = 7) walked on a treadmill at three different speeds while data were recorded simultaneously from the IPS and a force plate (FP). The IPS was compared against the FP by evaluating differences between the two instruments under two different assessments: (1) comparing the two peak forces at weight acceptance and push-off (2PK) and (2) comparing the absolute maximum (MAX) of each gait cycle. Agreement between the two systems was evaluated using the Bland–Altman method. For the 2PK assessment, the group mean of differences (MoD) was −1.3 ± 4.3% body weight (BW) and the distance between the MoD and the limits of agreement (2S) was 25.4 ± 11.1% BW. For the MAX assessment, the average MoD across subjects was 1.9 ± 3.0% BW, and 2S was 15.8 ± 9.3% BW. The results of this study show that this sensor technology can be used to obtain accurate measurements of peak walking forces with a basic calibration and consequently open new opportunities to monitor GRF outside of the laboratory.