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The Field Improvised eXoskeleton (FIX) final project report serves to explain and evaluate the results of the testing performed during the Fall 2020 and Spring 2021 semesters to assess whether the FIX prototype meets the design requirements. A full prototype was built to treat a distal radius fracture on Soldiers in the field by testing the ability of an “injured” volunteer to perform a “buddy drag”and comparing between a standard SAM splint and a Modified Splint built by the team. Similarly, the prototype was split into two parts: a Modified Splint subsystem and an external task subsystem for the “buddy drag.” The splint subsystem served the main purpose of improving upon the standard of care for splinting, which is a SAM splint. All subsystems were made of materials present in a Field Medic Pack or from materials that were considered easily accessible, such as straps and duct tape.
The general requirements for the prototype design were for the prototype to: stabilize the fracture site, be capable of performing the test adequately, be assembled quickly, minimize damage to the fracture, have clear fabrication instructions, stay within the given budget, be adjustable, apply an appropriate amount of pressure on the arm for the splint, prevent extra pain, and be comfortable. The fracture was proven to be stabilized using the first of two surrogate arms with an implanted fracture and hall effect sensor to measure maximum fracture displacement. All maximum fracture displacements of the Modified Splint subsystem of the prototype were less than the standard of care SAM splint, which made it an improvement of the standard of care. The “buddy drag” external subsystem of the prototype was proven to perform adequately by comparing a healthy “drag” to a “drag” using the external subsystem. The time taken to perform the “drag” was within 2 seconds of a healthy “drag” for a 10 yard distance for a small person’s weight and was tested up to a weight nearly 50 pounds more than the average weight of a soldier. The fabrication time for the entire prototype is 9 min and 10 seconds, which was considered a reasonable amount of time for a Combat Medic to spend assembling the prototype in the field. The prototype was proven to minimally damage the fracture site using the second surrogate arm that experienced a simulated strap tug similar to the “buddy drag” performed. Similarly to before, the maximum fracture displacement was less than the standard of care in this case. The fabrication instructions were proven to be clear after a volunteer not on the FIX team read over the instructions and provided feedback that was resolved by the FIX team. The prototype cost less than half of the given budget, so it stayed within budget. The prototype was proven to be adjustable through the use of straps and the application of the splints on different volunteers and members of the FIX team with different arm sizes. The splint pressure was tested using pressure sensors and a capillary refill test that compared the pressure applied by the standard of care SAM splint and the prototype Modified Splint. In this case, all pressure tests proved that the Modified Splint compressed the arm more than the SAM splint without restricting the blood flow of the arm, which would prevent further damage to the fracture. There was no extra pain applied during the “buddy drag” because a volunteer filled out a comfort questionnaire regarding their discomfort and answered that he did not experience any pain during the test after resolving a complaint about the strap rubbing by adding a more realistic outer garb to his arm. Lastly, the volunteers answered comfort questionnaires for the splint and external system regarding how comfortable they felt. The volunteers said their comfort ranged from completely comfortable to slightly less comfortable, but none of them were answered in the uncomfortable range. Overall, the full prototype met all requirements and was considered successful while a work-in-progress external system for the ammo carry done by the team was not considered in the final prototype due to time constraints.
Liu, Kelly; Dang, Duncan; Peñaloza, Karla; and Mondragon, Emi, "Field Improvised eXoskeleton (FIX) Final Project Report" (2021). Engineering Senior Design Reports. 44.