Team 3863 Pantherbotics is proud to release the latest iteration of our swerve drive!
Compared to our previous offseason swerve, this design is intended to reduce the number of unique parts, minimize cost, and increase assembly speed. The top and bottom plates were machined on our CNC router using 2D operations only. We were able to do so by removing the bearing pocket on the bottom plate and switching to use bolt heads to retain the X-contact 6816 bearing. The forks were cut out initially on the router, then the holes on top were done on our mill.
Regarding the steering, we chose to avoid using a VersaPlanetary as we found it was significantly more expensive than using spur gears, belts, and pulleys. The first stage is a 100:12 using 32DP COTS gears, and the second stage is using a 5mm pitch HTD belt and 3D printed pulleys. Currently, the total steering ratio is around 30:1, which is definitely a little on the low side. We’ll have to do more testing to see if this ratio is sustainable. The 32DP first stage could be swapped for an equivalent C-C 20DP reduction, which would net us a higher ratio. We are using a TT-6127 absolute encoder with a separate encoder gearing off of the first stage to sense wheel orientation.
For the drive, we are using a 3D printed wheel. For our ‘proof of concept’ modules, we have been printing them out of PETG. They’ve been surprisingly durable! However, we plan to print the final modules out of Nylon 910. The printed wheel has six 0.201" holes in a 1.5" bolt circle to affix the bevel gear to the wheel. The total drive reduction is 7.50:1, netting a free speed of 13.21ft/s with a NEO. It can be geared faster, if necessary. We plan on using the NEO hall effect sensors for sensing wheel velocity, but we can also opt to use Munchskull’s CIMCoder if necessary.
Google Photos link to an assembled module, here.
GrabCAD link (includes both STEP and SolidWorks native files)
As always, don’t hesitate to ask questions!