[ODE] Questions about wheel slip and damping

[Yizhen Zhang]

Hi, Michael,

Thanks a lot for your reply. But when I also set the
velocity for the rear wheels, it didn't seem to help
at all. Maybe the problem is with the hinge joint I
used for the wheels. Since after I changed the hinge
joints to hinge-2 joints for the wheels, the rear
wheels do not slip any more in steady state, and I
don't have to set velocity for them. However, I am
still wondering how to simulate and control a small
percentage of wheel slip during normal driving
conditions.

I also noticed that, even with the hinge-2 joints
model, if the friction coef mu is not set to dInfinity
(say 0.9) and the torque is set to more than
corresponding maximum friction/adhesion force the
ground can provide, the driving wheels will reach the
set velocity in 1 timestep, which means huge wheel
slip here. I am not sure if this is realistic.

Best regards,
Yizhen

> Date: Tue, 12 Oct 2004 17:50:37 +0200
> From: Michael Rauh <michael.rauh at gmail.com>
> Subject: Re: [ODE] Questions about wheel slip and
> damping
> To: ode at q12.org
> Message-ID:
> <de75db1a041012085068baf503 at mail.gmail.com>
> Content-Type: text/plain; charset=US-ASCII
> 
> On Tue, 12 Oct 2004 10:40:37 +0200, Pancini, Ettore
> <epancini at ferrari.it> wrote:
> > 
> >  what about the friction value you set on the
> contact created from rear wheels and ground?
> > 
> Of course the same as for the front wheels, e.g.
> mu=0.8 (with
> dContactApprox1) for one of my  front-driven cars. I
> observed similar
> behaviour as Yizhen when I built the first
> front-driven one. Setting
> the motor speed also for the rear wheels canceled
> that problem. The
> rear wheels are now rolling fine (with v = omega *
> r) as they should
> do. Did you observe something different?
> 
> Greets
> Michael



		
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