4165 Offseason swerve

[matthewdenny]

Originally Posted by Ether

I think Luke was comparing your 2-wheel arrangement to a swerve with only one wheel centered on the turning axis. In that comparison, it takes much more torque to steer the 2-wheel arrangement. Also, the kinematics with the 2-wheel arrangement are slightly compromised: there will be some wheel scrubbing.

Have you done calculations on the loading of that bevel gear bearing? It will see thrust, side, and cantilever loading.

Ok, got it. Yes there is noticeably more friction with the wheels out from the turning axis, but we calculate that we still can turn 90deg with a fully weighted robot in <.1s, which was acceptable for us. The 2 wheel arrangement allowed us to lower the cg, and keep everything COTS, which was a primary design concern.

As far as the bearing goes, we aren't sure where to find the spec on the bearing load limits or what kind of shock forces we can expect. We do anticipate that most thrust forces would be held by a needle roller bearing between the bevel box upper gear and vex gearbox though. The side and cantelever loads are a bit of a mystery, and any insight you could share on calculating that would be appreciated.