A5A6 Rev 1

Prototype 1 Conclusion

What went well

  • Belt drives: The belts performed well under the tested loads. They did not slip or produce much backlash. Using more professional belts and pulleys instead of FRC parts should only increase this success.
  • Differential: The gearbox was assembled well, had low backlash, and supported the tested loads. 
    • It would be nice to reuse the gears for the real version to avoid having to buy three more expensive gears

What to change

  • Weight of frame: Find a way to make a frame that is still strong enough to support everything without twisting/otherwise breaking, but ideally reducing the thickness and weight of the side plates and standoffs.
  • Overall design of gearbox: 
    • It's quite heavy since it's made of a solid block of aluminum
    • A bit clunky looking also
    • Maybe try to make it easier to manufacture?
      • Curves are hard to mill by hand
      • Inner holes are hard to CNC
  • Big pulleys mounted at the end: Makes it look clunky and adds weight as well
    • With more powerful motors, it may not be necessary to have any/a large reduction by pulleys
  • Belt tensioning mechanism: It takes a lot of force to pull the sliding plates enough to fully tension the belts, and then to hold it in place while tightening the screws; using a lead screw or something like that will make belt tensioning a lot easier.
  • Spacers on the small pulleys: Spacers were scraping on the wall. Not a significant design flaw in my opinion, I just forgot to put any clearance between them. This mistake will not happen again.


  • Maybe: Encoder mounts sticking out: Mounting the encoders at the end of the motor shaft means that they stick out a lot on the side, especially since they're on the other side of the pulley too. This isn't great, both for functionality and looks. 
  • Maybe: Easier to assemble gearbox area: The gearbox and end pulleys have to be assembled and mounted in a specific order, which also means that you have to take off the entire pulley to remove a side gear. Part of this is because of the VersaHub sitting inside the pulley with access to the set screw blocked, but even without that it would be nice to make it a bit easier.
  • Maybe: EE mounting coupler: I just copied an existing Pololu part, if we are still manufacturing it ourselves it doesn't need to have that specific design. Maybe it can be redesigned to better suit our purposes and/or be simpler to manufacture.
    • Holes in a square instead of a circle?
    • Constant diameter?