[ODE] which kind of parameters can influence the slip velocity?

[Jon Watte (ODE)]

That doesn't look quite right. I suggest you download and take a look at 
RayCar, which models a tire contact with slip (although it uses a ray, 
not a sphere, for a wheel).

http://www.mindcontrol.org/~hplus/raycar/

Cheers,

          / h+


彭兴文 wrote:
> These days, I want to set the contact.slip with reason in my car 
> simulation. So I want to find out which kind of parameters will 
> influence the slip velocity.
>
> First, I just add one wheel in the ODE. The wheel mass is 5kg and the 
> gravity is 9.81, the torque is add on the rolling axis. Then I set the 
> contact parameters like this:
>
>  ontact[i].surface.mode = dContactFDir1 | dContactMu2 | dContactSlip2 
> | dContactBounce | dContactSoftERP |  dContactSoftCFM | dContactApprox1;
>              
>         FDIR1 =  wheel rolling axis (not the direction that the wheel 
> rolling in)
>     
>         contact[i].surface.mu = 0.7;
>         contact[i].surface.mu2 = 0.7;
>         contact[i].surface.slip2 = 0.01;
>         contact[i].surface.bounce = 0.001;
>         contact[i].surface.soft_erp = 0.9;
>         contact[i].surface.soft_cfm = 0.01;
>
> And the wheel's radius is 0.1m, the wheel width is 0.15m.
>
> I get these data from ODE:
> torque = 0.5 slip2 = 0.01 Angular velocity - linear velocity = 0.01667
> torque = 1.0 slip2 = 0.01 Angular velocity - linear velocity = 0.03333
> torque = 1.0 slip2 = 0.02 Angular velocity - linear velocity = 0.06667
>
> there is no effectives when I changed the wheel width, the wheel mass, 
> the  mu  mu2, bounce soft_erp and soft_cfm. But when I changed the 
> wheel radius to 0.2,it will be:
> torque = 0.5 slip2 = 0.01 Angular velocity - linear velocity = 0.00833
>
> So it seems the torque , contact.slip2 and the wheel radius will 
> influence the slip velocity(Angular velocity - linear velocity). Is 
> this true? And can someone help me
> to understand how these parameters influence the slip velocity?
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