[ODE] Slip detection

[Railey, Ken]

Excellent. Thanks guys! 



-----Original Message-----
From: ode-bounces at q12.org [mailto:ode-bounces at q12.org] On Behalf Of Jon Watte (ODE)
Sent: Saturday, August 13, 2005 10:03 AM
To: Charlls Quarra
Cc: ode at q12.org
Subject: Re: [ODE] Slip detection

Yes; my formula was specifically for sideways slip.

If you want just slip, period, then the easiest way to do that is to get 
the world velocity of the body (wheel) at the contact point. There's 
even a call to get it: dBodyGetPointVel(). If it's non-0, then you're 
slipping. Note that there will always be a small amount of slippage even 
whiel rolling, because of simulation approximations, so you should 
subtract some threshold value.

Cheers,

			/ h+


Charlls Quarra wrote:
> Actually velocity at the contact point (assuming a sphere) is ( w x r + 
> v ), where w is the angular velocity times the axis of rotation, r is 
> the vector that point from center of sphere to contact point, and v is 
> the linear velocity. when w x r + v is the zero vector you have rolling 
> contact. Otherwise you are slipping

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