The team's first functional prototype is shown in the images below.
Movement
In the two videos, the full revolution of the mechanism is shown. When the crank is rotated, there is a distinct "flicking" motion as estimated by our kinematic analysis. The flicking motion occurs at the bottom of the revolution of the joint 6.
Manufacturing and Materials
The materials used and their specific manufacturing methods are included in the following table.
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Crank Handle.3MF
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Joint 7
Notes for Final Prototype
- The spacers and washers utilized in this design were not as expected in the CAD. Currently additional M3 nuts are acting as spacers in order to provide smooth motion.
- The ternary link short end is not the correct dimension, and we are noticing the angle between links 2 and 3 is not changing as much as anticipated in the Python analysis.
- The ground position of the ternary link is not in the correct place. This may also be contributing to the angle issues noted in (3).
- The ternary link may need to be keyed in the future in order to mitigate slip on the shaft. Currently, the M6 holes were down sized to 5.80 in order to create a snug, press-fit.
- The team will need to replace the crank handle with a 12V DC motor, H-Bridge, and Arduino. Appropriate calculations may be required to ensure the motor can supply enough torque.