QL+ Program Manager:
Kristie Yelinek
The mission of the George Washington University is to educate individuals in liberal arts, languages, sciences, learned professions, and other courses and subjects of study, and to conduct scholarly research and publish the findings of such research.
kristie.yelinek@qlplus.org
Ms. Salak is a retired Army veteran who enjoys an active lifestyle. However, Ms. Salak recently sustained an injury and now uses an above-knee prosthetic. To stay active, she frequently rides her handcycle, both leisurely on local trails and competitively in marathons....
The GW Hiking Prosthetic challenge is being executed in accordance with the Quality of Life Plus (QL+) Program. The specific client, or challenger, for this project, is Rob Jones, a double transfemoral amputee. Rob served as a combat engineer in the Marine Corps; during a deployment to Afghanistan in 2010, he was wounded in action by a landmine....
Hiking and walking on uneven terrain are challenges for many transfemoral amputees. This challenge becomes even more difficult when someone is a double transfemoral amputee. Quality of Life Plus and our client, Rob Jones, presented us with the challenge to design and build a solution that will allow him and other prosthetic users to hike on uneven terrain more efficiently....
There were several milestones accomplished this year along with some outside challenges that altered the project timeline. For the automated spring movement subsystem, a novel stepper motor threaded rod linear actuator design to move the springs inward and outward along the wobble plate was developed. A mock system utilizing one set of smaller components verified the feasibility of the design approach. A full-scale system was then designed in CAD and all necessary parts were either sourced or requested from the machine shop using drawing files. Due to delays in receiving parts from the machine shop, the full-scale system did not start being built until the Spring 2021 semester. Furthermore, the machine shop delays have prevented experimental testing to confirm the necessary stepper motor specifications and power distribution requirements. In addition to building and testing the full-scale automated spring wobble plate in the Spring 2021 semester, a power distribution subsystem was sourced to operate the stepper motors and scissor jack lifts. For the stabilization mechanism subsystem, several concepts were explored, and it was determined that the scissor jack lifts design was the best path forward. The scissor jack lifts initial concept was tested. In the Spring 2021 semester, the stepper motors were secured to the scissor jack threaded rods via a U-shaped brackets and couplers. Unistrut beams were welded to the tops of the scissor jacks to offer horizontal contact points with the upper seat plywood board. Due to machine shop delays, additional safety features were scaled back, including an adjustable footrest and enclosed ball socket. For the calibration procedure subsystem, a python script was developed that yielded the same output as the spreadsheet currently used by WRNMMC to determine/calculate corresponding MGH values (ex. MGH80%) at different spring positions, by inputting the participant’s forward/backward moments and angles yielded by the physical calibration procedure. Additionally, a python script was developed that allows WRNMMC to explore and calculate the anthropometric calibration method. Furthermore, three sets of calibration wedges were designed offer 5-, 7.5-, and 10-degree chair tilts that allow WRNMMC to explore tilting the chair during the calibration procedure to different known angles. The team was able to visit WRNMMC early in the Spring 2021 semester, where data was collected, and the code was tested.
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