6 Wheel Drive vs. 8 Wheel Drive

[Aren Siekmeier]

2175 went 10 wheel with 4" plaction this year for a few reasons: As mentioned, you can hang more of your robot off with wheels closer together (specifically, with our CG just behind the wheels, you could get as far as half the robot hanging off, though we never did). Also, we need to not bottom out on the bump, but also have as low a cg as possible, so many small wheels did this for us. We dropped the center 3 on each side (6 total), so it behaved much like an uneven 8 wheel in terms of stability, which was nice for shooting, balancing, and just for stability in general. Not really many problems turning (contact rectangle 9" long by 28" wide), though it did stall out when attempting minor adjustments (the driver got good at it). I imagine a 6 wheel would do better there, since it can lift it's end wheels off the ground in the turn. Also lots of contact surface, so some could argue more traction (though I haven't seen or even sought data to support this).

We definitely did our share of CADing the wheel layout, checking for clearance, cutting cardboard profiles, making wooden wheels, etc.

Unfortunately, some other poor design (little review, not enough manpower, not enough time, etc.) meant we didn't actually get our CG low enough to get over the bump (or do a lot of other things).