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Unread 09-12-2013, 15:29
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@JohnVNeun
AKA: John Vielkind-Neun
FRC #0148 (Robowranglers)
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Re: Omni vs Mecanum CoF ?

Quote:
Originally Posted by gpetilli View Post
AndyMark is good about posting forward vs. side for their wheels, so I believe that the CoF comparison is valid (never expected it tested at 45deg). What I was less sure of is that the CoF measurement would have exhibited the sqrt(2)/2, but I believe your diagram predicts that it would. IFI does not report forward vs. side for their mecanum and given the similarity in CoF to the Omni, I am highly suspicious that they are reporting the CoF for the roller material, not the wheel assembly.
We report CoF for an overall drive assembly, weighted to 150 lbs (120 lb robot + 14 lb battery + 20 lb bumpers = 154 lbs). In this way, we are reporting the average CoF of a drive train "in application."

These tests were done with locked wheels (not locked rollers) using the tilted incline method (which we believe allows for greater accuracy than the pull test method).