Projects Archive

The devices our student teams design allow wounded patriots to overcome many of their challenges and get back to doing the things they love. This support can change their lives.

Meet the Challengers
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Para bobsled launcher


Para-athletes that are part of the International Bobsleigh Skeleton Federation (IBSF) require an alternate starting method for the launch phase of a bobsled run. A current bobsled launcher exists to create an even push and start time, but this launcher is for competition use only. It is difficult to transport the competition launcher between training camps and it is too expensive to build multiple. The practice launcher should be easy to move and ship back and forth between the two American bobsled tracks; Lake Placid, NY and Park City, UT. To fill the need for a training launcher, the team partnered with Quality of Life + (QL+) to design and create a safe, cost effective, portable, and fully functional practice launcher to meet the customers’ needs. After generating multiple concepts, the team chose a design called “Matter of a Pinion.” This concept utilizes a motor to rotate a pinion that pushes forward a gear rack and actuating arm. To ensure the launcher would be able to provide enough force, calculations were performed. These analyses influenced the length of the pushing arm, pinion size, and motor selection. The actuating arm is made of a hollow square 2” x 2” x 0.125” Aluminum 6063 tube, with an electromagnet to attach to the back of the bobsled. The steel helical gear rack is attached to the top of the actuating arm. To propel the gear rack, a 1.5 inch pinion is rotated by a 5 horsepower motor. The motor can provide a speed of 1750 RPM with an accelerating torque of 180 in-lbs. A variable frequency drive controls the speed of the motor and communicates with the operator’s hand controller. The hand controller contains both a remote and dead man switch for safety. To ensure the gear rack fully resets between launches, limit switches were implemented. A welded Aluminum 6063 frame is covered by ABS paneling and weather stripping to protect all components. On the outside of the enclosure, there are handles and wheels for portability, as well as a height adjuster to ensure the launcher is level. After completing the design and build phases, the launcher was tested. The launcher meets 93% of the target specifications. Overall, the team is confident that the launcher will provide a launch similar to the competition launcher, and will enhance the para-athletes training and performance.

Unstable chair biofeedback


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.

Shower leg for above knee amputee


The primary objective of the shower leg prosthetic was to design and develop a unit that provided our user the ability to stand in the shower. Throughout the completion of our project, we focused heavily on his safety and comfort, as well as his desire to have full access to his residual limb. We aimed to implement as many features as possible that catered to the transportability of the prosthetic for his athletic travel demands. Multiple iterations of the prosthetic were created to influence the directional changes needed for the final product. The largest impact came from the engineering prototype, where the bottom design of the seat was drastically redesigned to ensure our final print would be without error. It was also in this iteration that we opted for ASA material instead of ABS, for reasons regarding improved mechanical properties and its resistance to UV, weather, and warping. The testing that took place that directly affected our prints was the tolerance testing in DFX, while motion capture testing confirmed the choice of cane we used. Mechanical testing with ANSYS simulation provided the expected performance of our design under load, and highlighted potential areas of concern. An unexpected issue we faced with the production prototype was with the bottom TPU component between the seat and the cane, where it bent under zero load. Our solution was to solidify this joint by either coating the exterior with epoxy, covering the shaft with a clear tube, or substituting the TPU altogether with a brazed piece of steel. Moving forward with the latter, we were able to remove the risk entirely, while still maintaining the height adjustability and portability of the shower leg.

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