Golf Prosthesis Final Design Report (P7)
After reviewing all four conceptual designs we narrowed down our choices in order to develop final designs. Both designs address the problem definition and meet the objectives we set out to accomplish. The adaptive golf sleeve is a completely independent device where bilateral amputees will have full use of their prosthetic hooks while playing golf. The adaptive golf cuff is also a simple design that assists bilateral amputees with gripping the club as if their hooks were their hands. The cuff will give them the most realistic golf experience due to its similarity to an actual golf swing. Finally, the slotted wrist design is a concept we initially developed before we understood the importance of hooks for bilateral amputees. After understanding the importance of the hooks we adapted the slotted wrist to incorporate the gripping force of the hooks to assist in swinging a golf club.
One important consideration for our final design is that we only have a general idea for how well a specific design will be effective. We won’t know the effectiveness of a design until we’ve developed a prototype and tested it. Also, every one of our concepts will be relatively cheap to manufacture. With this in mind we decided to proceed with three final designs including the adaptive golf sleeve, adaptive golf glove, and slotted wrist. We decided to leave out the single arm design due to its lack of feasibility. It is more effective to have a golf swing that incorporates the use of both arms. Swinging with both arms will render better results while golfing.
Supporting Preliminary Analysis
The primary analysis for our golf prosthetic is focused on a worst case scenario where the user swings a golf club, using the slotted wrist design, and hits the ground at impact, transferring nearly all momentum of the club into the ground. By recognizing this problem we can develop a model for how much force is exerted from the ground onto the club and analyze the threaded fastener that connects the slotted wrist design onto a prosthetic arm.
Figure 20 below provides a brief sketch, list of assumptions, and governing equation for the problem. The assumptions are important because they allow us to simplify the problem, making the analysis feasible. After using the equation for impulse/conservation of momentum, an impact force of 3350N was calculated.
Once the impact force was calculated we could analyze the force on the threaded fastener to determine the stiffness. Figure 21 depicts a sketch and list of equations used in order to determine the stiffness of the threaded fastener. We want to use a light weight metal such as aluminum for the slotted wrist design so the user has an easier time swinging a golf club. After analyzing an aluminum threaded fastener, a stiffness of 563304 in-lb. was calculated.