# [ODE] nonholonomic vehicle path following

Ke kxubb at yahoo.com
Mon Jun 11 11:29:10 MST 2007

```Thank you all for your advices.
We really appreciate that.
After tuning up the parameters like steering,linear
velocity, our car can reach one target position w/
less than 5% error. But that set of parameters may not
give us good error control for other testing cases.But
we need to find a good set of parameters good for
general cases. Looks we have to tune the control
parameters case by case.
Please point me out if I was wrong.
Again,thank you all.

Sincerely,
Ke
--- Patrick Enoch <Hendrix_ at gmx.net> wrote:

> You should not copy the steering values from one car
> to the other
> verbatim, but calculate the difference to the
> desired path and apply
> that to the car. This way you will have a
> self-correcting steering. I
> hope this is stable, which depends on how big the
> errors are from
> step to step.
>
> On 11.06.2007, at 08:29, Jon Watte (ODE) wrote:
>
> > Given that ODE is a semi-implicit first-order
> integrator, much like
> > most
> > other game physics engines, that is correct. There
> will always be some
> > error. In fact, if the circle is parametrically
> defined, there will
> > always be some error with any kind of numerical
> integration of this
> > kind. The question you need to answer is "how big
> an error can I
> > accept," and then see whether you can tweak the
> tunable parameters
> > (response force, dampening, time step size, etc)
> to hit that goal.
> > That's true for any numerical integration method;
> not just ODE.
> >
> > Cheers,
> >
> >           / h+
> >
> >
> > Ke wrote:
> >> So our 4-wheeled vehicle simulated by ODE is not
> able
> >> to perform such path following tasks accurate
> enough.
> >> For example, say, we asks the vehicle built by
> ODE, to
> >> follow a given circle path. The trajectory of the
> >> vehicle would not be exactly same as the given
> one,
> >> due to the accuracy of ODE's integrator and
> solver.
> >> Please point me out if I am wrong.
> >> Thanks again and we appreciate your input.
> >>
> >> Sincerely,
> >> Ke
> >>
> >>
> >
> > _______________________________________________
> > ODE mailing list
> > ODE at ode.org
> > http://ode.org/mailman/listinfo/ode
>
> _______________________________________________
> ODE mailing list
> ODE at ode.org
> http://ode.org/mailman/listinfo/ode
>

____________________________________________________________________________________
Be a better Globetrotter. Get better travel answers from someone who knows. Yahoo! Answers - Check it out.