Golf Prosthesis Final Design Report (P10)
Design Verification Plan
Testing our final designs was an intricate process due to the fact that upper extremity bilateral amputees are extremely rare. Less than one percent of all amputees are bilateral amputees and of that one percent, few play golf. This is due to the inherent lack of innovation or adaptations that have been created to address this issue. Fortunately, through an independent search we came in contact with two bilateral amputees, both of whom have experience playing golf, John Lawson and Jim Taylor. However, because John Lawson lives in Ohio and Jim Taylor lives in Washington State, we were only able to have Jim Taylor drive down to test our devices twice over the course of a year. To compensate for the lack of personal feedback, we decided to build our own set of golf arms, which then allowed us to test our prototype designs almost immediately after fabrication.
We built two pseudo-prosthetic arms, which we then used to mimic how a body powered prosthetic device might interact with our prototype designs. To accomplish this, two prosthetic hooks were donated to us from Jim Taylor. These pseudo-prosthetic arms provided us with instant feedback about our prototypes and eventually lead to two working designs. Using our two designs we successfully hit golf balls both out of the rough, off of the fairway, and off of a tee using irons, woods, and drivers. These personal test trials allowed us to improve our design with each iteration and create a functioning prototype before meeting with Jim Taylor in late November, where he tested out both of our designs and compared them to his current working prosthetic golf arms.
During Jim Taylor’s final visit in November we had him personally test our two prototype designs in order to compare and contrast our designs with his current set of golf arms. Using his own set of golf arms, we had Jim hit 5 golf balls, using his seven iron, while in line with a target one hundred yards away. The results from the test are shown in Table 4 below.
After each practicing swing and after each shot Jim would have to readjust the head of the golf club. Typically the head of the golf club would rotate counter clockwise or shut the face of the golf club after impact with the ground. During testing Jim attempted to use our devices. He was successfully able to put on and take off each device; however, Jim was not actually able to hit a golf ball with our devices because he felt uncomfortable and unsafe. Jim’s everyday prosthetic arms not only lack the appropriate gripping strength of his golf arms, but also have a host of issues associated with them, such as durability and orientation, that make them difficult to golf with and that were not taken into account while designing our two prostheses. Prior to testing we had not considered the limitation of Jim’s every day prosthetic arms and how uncomfortable it would make him feel. Although Jim uses these arms for most of his everyday functions, he was not comfortable golfing with these arms, and hadn’t done so in ten years.
We also discovered that the angle created at the interface between our golf attachments and Jim’s hooks made him feel uncomfortable. Our devices attempted to simulate the natural wrist hinge of a fully able-bodied golfer; however, we did not consider that the angle we created would actually make the user feel more uncomfortable while using our device. In fact, upon further analysis we discovered that with Jim’s golf arms the golf club functioned as a direct extension of his arm, where no wrists hinge was present.