| dc.description.abstract | This dissertation explores the viability of two prospective wearable mechatronic devices. The first is a swing-assist knee prosthesis for individuals with transfemoral amputation, and the second is a backpack-wearable thruster intended to counteract impending falls in people at fall risk (e.g., the elderly). The swing-assist knee was intended to provide the advantages of compactness and low-impedance interaction provided by passive prostheses, with the swing-phase robustness and assistance of powered prostheses. The proposed device employs passive stability for stance support and incorporates a small motor to assist swing phase motion. A prototype was constructed and experimentally evaluated on a single transfemoral amputee, walking on an instrumented treadmill at three speeds. The results indicated a reduction in pre-swing hip moments and improved consistency and repeatability of knee motion across all walking speeds, compared to the daily-use passive prosthesis. The second part of this dissertation examines the feasibility of a fall prevention device in the form of a cold-gas thruster (CGT). The CGT, intended to prevent backward falls for individuals at fall risk, is comprised of a pressurized air tank combined with a custom electrically actuated high-flow-capacity valve and servo-controlled nozzle, which are employed together to create a thrust to restore balance in instances of an impending fall. This research involved performing design calculations; constructing a prototype system to provide appropriate thrust characteristics; designing a controller to detect impending falls and provide corrective force; and testing the device on an experimental apparatus that represented a human user. Experiments on a simple experimental model (a rocking block) were conducted, where perturbations were introduced to the block and the responses with and without the CGT were compared. The results were used to evaluate and quantify the assistance provided by the device as well as the reliability of the CGT controller. According to the results, the autonomously controlled CGT significantly improved the perturbation rejection of the block. Finally, some remarks on the differences between the rocking block and a human body and possible changes to the controller for use with humans are provided. | |
