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| All of the pictures above show the second prototype being assembled. The pin fits through two holes in the "arm" and holds one of the brass weights, a gear, and bearings. The vise was used to press-fit the entire assembly together. |
The final assembly, with the motor casing attached is shown below. (The lid is not placed on the box to show the fit of the assembly.
During the week we also tried to test the system. We went to Dr. Kim's lab and used the force plate again, with the user standing on the force plate while wearing the system. However, the test was conducted the Friday before spring break, when Isaac (the normal wearer) was gone. Kimberli wore the brace during testing, and there was still quite a bit of wiggle that we had hoped to eliminate with the double-mass system. It was unclear whether the design did not address the issue as well as hoped, or if the wiggle was produced because the brace did not fit well on Kimberli. (The brace was custom-designed for Isaac's foot, and was significantly larger than Kimberli's.) This is one thing that needs to be double checked after break when all of the group members return.
Another problem was experienced during testing. The upper mass hit the lower gear when it spun. We will either need to add a bit of clearance or file down the lower gear to reduce this problem.It was also found that the upper gear sometimes became out of alignment, so that the gears were not always opposite of each other. Both of these problems are likely due to the fact that the bearings (on the pin) are somewhat loose and will need to be glued to the brace to reduce movement.
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| As can be seen, the brace sits much lower on the foot/ankle as it was big on Kimberli's leg. (Isaac was not available for testing.) |
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| Video of one of the tests performed while standing on the force plate. |
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