Re: simulated arm/gripper

On Tue, 19 Jul 2005, Tim Oates wrote:

> I've written a simulation of a 6-DOF arm/gripper that's working.  I have
> two questions:
> 
>   (1) When all of the joint angles in the multibody are zero, the arm is
>       pointing down.  I'd like to be able to rotate the arm so that when
>       all of the joint angles are zero it's pointing in an arbitrary
>       direction.  I've experimented with various rotate methods on the
>       multibody and its joints, but either get no effect or erratic
>       behavior.  Does anyone know how to do this?

This should be what's referred to as "relative rotation" of the joint.  There
are methods for setting relative rotation in the Joint class.

>   (2) Does anyone have any advice on how to parameterize the simulation to
>       give the gripper, which just opens and closes, the best chance of
>       getting a good grip on objects in the simulated world.  I've set
>       friction on the gripper and objects to be high.  I've also played
>       around with the coefficient of restitution (set-e).  Are there are
>       things I can/should do?

I would try setting the "mu" value to be quite high.  Although the 
documentation may say it's a value between 0 and 1, that information is 
outdated.  mu can now be a value between 0 and infinity, so you can provide
arbitrarily high values.

- jon klein

_______________________________________________
breve mailing list
[email protected]
http://lists.spiderland.org/mailman/listinfo/breve