[ODE] controling joint forces

[Manohar B.S]

Hi,
    Is there a comprehensive literature on how joint
contraints are done using LCP solver? I guess both the
math and algorithm are crucial.

Cheers!
Manohar
IISc, Bangalore.
http://ssl.serc.iisc.ernet.in/~manohar/research.htm


--- Jaroslav Sinecky <jsinecky at tiscali.cz> wrote:

> I'm not exactly the ODE experienced one, but as no
> other replays, I tell you
> my opinion based on part of ODE code I have seen.
> 
> I think it's not easy to implement what you want (by
> the way what for do you
> need to add joint forces only above certain value?).
> Joints actually don't
> simply add forces to bodies, joint forces in every
> island of bodies are
> interdependent, when one joint applies more force,
> some other joint may
> apply less force, so that joint constraints are
> maintained. That's what the
> LCP solver does.
> Maybe some similar trick as for friction limit
> contact could be used, but I
> don't know how this is done.
> 
> Cheers!
> Jaroslav
> 
> 
> > -----Original Message-----
> > From: ode-bounces at q12.org
> [mailto:ode-bounces at q12.org]On Behalf
> > Of Piotr Obrzut
> > Sent: Monday, September 12, 2005 2:24 PM
> > To: ode at q12.org
> > Subject: [ODE] controling joint forces
> >
> >
> > Hi,
> >
> >    I'm back to my ODE project again and I started
> to have more complex
> >    needs:
> >
> >    I want to control all data about forces that
> ode aplies to bodies
> >    (the most interesting are joint forces).
> Normaly I use "joint
> >    feedback" info (btw. I still must test the
> patch by Jaroslav
> >    Sinecky) and it served me well. Now I want to
> controll added
> >    forces: I want let joint to add its forces only
> when the force will
> >    be greater than certain value. The most
> convenient way will be to
> >    have special *callback* that will be called
> each time joint will want
> >    to add forces to body.
> >
> >    I didn't have to look under ODE's interfaces
> before, so I wanted to
> >    ask first more experianced users if this could
> be done that way and
> >    if later this small change could be added to
> ODE's cvs. I don't
> >    want to make my own joints  and have my own
> version of ODE
> >    (I use it through Crystal Space interface that
> is prepared to work
> >    with official ODE's cvs version).
> >
> >
> >    So ODE devs: could this change be added to cvs?
> >
> >    all ODE experienced: could I do this that way?
> >
> > --
> > Greetings,
> > Piotr Obrzut
> > mailto:piotr_obrzut at o2.pl
> >
> > _______________________________________________
> > ODE mailing list
> > ODE at q12.org
> > http://q12.org/mailman/listinfo/ode
> 
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> 



	
		
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