Quote:
Originally Posted by kramarczyk
Should have posted this earlier...
The center axle in a 6WD system carries a disproportionate amount of weight on it. In a uniformly distributed frame the center axle carries about 62.5% of the weight vs. 18.75% for the outer axles. Since traction is proportional to weight, increasing the friction coefficient at the center axles has the biggest bang for the buck in terms of pushing force while minimizing the reduction in turning due to high skidding losses.
Assuming a uniformly distributed 120lb bot with 6 skyways (0.7 CoF) then the pushing force is 84 lbs. Swap the center wheels to a ridgetop material (1.3 CoF I think) and the pushing force jumps to 129 lbs (120*.625*1.3+120*.1875*.7*2), an improvement of over 50%. In reality most bots are not uniformly distributed, but instead biased to the center which makes this change even more significant.
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Also wouldn't changing the center wheels to omnis allow other robots to translate you sideways in addition to being able to spin you around the center axis? Then they wouldn't even have to hit you on the corner, any part of either side of your robot perpendicular to the drive direction would do.