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Unread 27-05-2013, 14:48
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Re: Team 2052's Mecanum Showcase!

Quote:
Originally Posted by pntbll1313 View Post
You are correct in that static friction is the only force pushing the robot. maybe slip is not the word I'm looking for. What do you call when the rollers spin, not the wheel itself. Slip of the ROLLERS is different than static friction being broken between the rubber and the carpet. When I use the term slip for the rollers I mean the rollers free spinning.
I don't see how to make this a 'cancel out' situation: how does it overcome the phenomenon that mecanums break traction before any tank drive with at least the same* CoF and weight? If the issue is slipping (which is why I asked), it's not CoF vs CoF issue; it's the geometry of the wheels. The fact that mecanum CoFs are then 40-75% that of most tanks only serves to compound this.


Roller slip will vary by specific DT, but not nearly as much as between mecanum and tank in general, and it's not helpful in strafing. It's also (thanks to Ether), not overly difficult to model the description, at least to the point of illustrating its negative effect. As the paper explains, the friction that keeps rollers from slipping adversely effects mecanum's strafing traction. If this is what we're talking about, I don't understand the implication that driving the wheels produces more tank-like results.

*Apparently also lower, to a factor of sec(α)--Ether's paper is great.
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