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The vibrations and significant play between the links caused would sometimes cause the mechanism to fall apart. We addressed multiple reasons for these issues.
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The second issue was imprecise measurements of the steel rods. Our initial measurements for the rods were determined by the CAD model. We used the CAD model to measure the rod lengths for the gears and limbs but eyeballed the motor transmission rod due to time constraints.
Finally, our initial assembly was poorly done. We did not adequately plan the order of assembly. Press-fits had to be done multiple times to correct assembly errors, such as when a part needed to be press-fit while already attached to the mechanism. This degraded the quality of our prints.
For the final assembly, we used SLA prints. The higher resolution of SLA printers meant that the resultant prints were more precise. This meant tolerances were better for press fitting, and connections between parts were cleaner. We also increased the size of the end caps which held the limbs to the steel rods. Finally, we used precise measurements for cutting the steel rods.
As a result, the motion became much smoother:
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