[ODE] Car Physics

[Brent Burton]

On Mon, 19 Apr 2004, Steve Eckles wrote:
> Thanks, I'll give it a try. Any other suggestions? Do you have any code I
> could look at?

(jumping in here...)

Other suggestions for roll-over:
* CG is just too high for the car.  Place it about as high
  as the top of the tires.  That is close to where many sedan
  CGs are.
* Springs are too soft.  Increase spring rate, and increase dampers.
* Any anti roll bar simulated?  Are they strong enough and do
  the forces act in the proper direction?
* Too much tire grip.  Real tire grip changes with the camber and
  slip angle.  Grip (holding forces) increase up to some threshold,
  the decrease again after that threshold.  "Slip Ratio" and "slip
  angle" are good terms for a websearch.

The source code for an older version of Racer (0.5.0f) is on
the Racer website.

Another simulator is Vamos.  I've not tried it, but it's an
open-source project and you can get the source from
http://vamos.sourceforge.net/

Both Racer and Vamos use the Pacejka tire force model.

The "pendulum model" isn't a good way to stabilize the car.  It
adds considerable unrealistic weight, and in turns the car will
lean opposite reality (it will lean like a motorcycle).  A
pendulum car will also nose-dive during acceleration and ride
nose-high during braking...  Hmmm, sounds like helicopter dynamics.

-Brent