[ODE] Slip values and Pacejka Magic Formula

[Russ Smith]

Andrew Stunell wrote:
> 
> see http://www.esbconsult.com.au/ogden/locost/phors/phors.htm
> 
> about magic formula part 21 and 22 I think. This uses a variety of a 
> formula developed in a paper by Pacejka.

okay, to try and answer your question:

consider a rotating tyre in contact with the ground (i.e. the vehicle
is moving with a velocity V). if a transverse force F is applied to the 
wheel (i.e. perpendicular to the direction of motion), the tyre will 
reach a steady state where it 'slips' in the transverse direction with 
a velocity proportional to F and V. the scaling factors depend on the 
environment. this behavior can be simulated in ODE with the 'slip' 
contact parameter. 'slip' basically says that a force at the contact 
should produce a resulting velocity (NOT an acceleration, as would 
normally be the case). note also that slip is independent of 
static/dynamic friction - there is no threshold.

does this help?

russ.

--
Russell Smith
http://www.q12.org