[KDL] Future plans: Collada import and constraint specification

Hi all,

>From a post in another mailing list [1] I got news that there are plans of
adding Collada-based input to KDL, for describing the kinematics and
dynamics of chains/trees. I've been looking into the Collada 1.5 specs
lately and the idea of having Collada-based persistent storage seems very
appealing.
I also read that there are plans for incorporating constraint-based solvers
into KDL. Does this refer to iTASC, and more specifically, to the
implementation that is currently being incorporated into the Blender game
engine?. On this same subject, do your plans also cover representing
constraints with the Collada standard?. If so, I'm wondering if Collada is
expressive enough to describe the scenarios that your constraint solvers
admit. For example, I have found no way of expressing constraint hierarchies
other than resorting to the <extra> element.

Thanks in advance for feeding my curiosity!

Adolfo.

[1] ROS users:
http://sourceforge.net/mailarchive/forum.php?thread_name=398e6e709112008...

Ruben Smits's picture

[KDL] Future plans: Collada import and constraint specification

2009/11/22 Adolfo Rodríguez Tsouroukdissian <adolfo [dot] rodriguez [..] ...>:
> Hi all,
>
> From a post in another mailing list [1] I got news that there are plans of
> adding Collada-based input to KDL, for describing the kinematics and
> dynamics of chains/trees. I've been looking into the Collada 1.5 specs
> lately and the idea of having Collada-based persistent storage seems very
> appealing.
> I also read that there are plans for incorporating constraint-based solvers
> into KDL. Does this refer to iTASC, and more specifically, to the
> implementation that is currently being incorporated into the Blender game
> engine?.

It does refer to iTaSC, an it will be similar to the implementation
that is incorporated into the Blender game engine, but since that
implementation is highly coupled with some Blender internals, it will
not be entirely the same.
The idea is however to use the Collada format to interchange task
specifications between different platforms/implementations. So you
would be able to use the specification you made in Blender on your
real robot using for instance the KDL implementation.

> On this same subject, do your plans also cover representing
> constraints with the Collada standard?. If so, I'm wondering if Collada is
> expressive enough to describe the scenarios that your constraint solvers
> admit. For example, I have found no way of expressing constraint hierarchies
> other than resorting to the <extra> element.

For now we will be using the <extra> element. I have currently no idea
on how to propose a new element for the Collada standard.

> Thanks in advance for feeding my curiosity!

Mission accomplished ;)

> Adolfo.
>
> [1] ROS users:
> http://sourceforge.net/mailarchive/forum.php?thread_name=398e6e709112008...
>
> --
> Adolfo Rodríguez Tsouroukdissian, Ph. D.
>
> Robotics engineer
> PAL ROBOTICS S.L
> http://www.pal-robotics.com
> Tel. +34.93.414.53.47
> Fax.+34.93.209.11.09
> AVISO DE CONFIDENCIALIDAD: Este mensaje y sus documentos adjuntos, pueden
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[KDL] Future plans: Collada import and constraint specification

2009/11/23 Ruben Smits <ruben [dot] smits [..] ...>

> 2009/11/22 Adolfo Rodríguez Tsouroukdissian <
> adolfo [dot] rodriguez [..] ...>:
> > Hi all,
> >
> > From a post in another mailing list [1] I got news that there are plans
> of
> > adding Collada-based input to KDL, for describing the kinematics and
> > dynamics of chains/trees. I've been looking into the Collada 1.5 specs
> > lately and the idea of having Collada-based persistent storage seems very
> > appealing.
> > I also read that there are plans for incorporating constraint-based
> solvers
> > into KDL. Does this refer to iTASC, and more specifically, to the
> > implementation that is currently being incorporated into the Blender game
> > engine?.
>
> It does refer to iTaSC, an it will be similar to the implementation
> that is incorporated into the Blender game engine, but since that
> implementation is highly coupled with some Blender internals, it will
> not be entirely the same.
> The idea is however to use the Collada format to interchange task
> specifications between different platforms/implementations. So you
> would be able to use the specification you made in Blender on your
> real robot using for instance the KDL implementation.
>
> > On this same subject, do your plans also cover representing
> > constraints with the Collada standard?. If so, I'm wondering if Collada
> is
> > expressive enough to describe the scenarios that your constraint solvers
> > admit. For example, I have found no way of expressing constraint
> hierarchies
> > other than resorting to the <extra> element.
>
> For now we will be using the <extra> element. I have currently no idea
> on how to propose a new element for the Collada standard.
>

I wasn't suggesting something as ambitious as expanding the standard ;-),
but rather wondering if part of the existing infrastructure could be used
somehow (e.g., the <rigid_constraint> element). Then again, expressiveness
seems to be limited, so using the swiss-army <extra> element seems to be OK.

>
> > Thanks in advance for feeding my curiosity!
>
> Mission accomplished ;)
>

:)

> > Adolfo.
> >
> > [1] ROS users:
> >
> http://sourceforge.net/mailarchive/forum.php?thread_name=398e6e709112008...
> >
> > --
> > Adolfo Rodríguez Tsouroukdissian, Ph. D.
> >
> > Robotics engineer
> > PAL ROBOTICS S.L
> > http://www.pal-robotics.com
> > Tel. +34.93.414.53.47
> > Fax.+34.93.209.11.09
> > AVISO DE CONFIDENCIALIDAD: Este mensaje y sus documentos adjuntos, pueden
> > contener información privilegiada y/o confidencial que está dirigida
> > exclusivamente a su destinatario. Si usted recibe este mensaje y no es el
> > destinatario indicado, o el empleado encargado de su entrega a dicha
> > persona, por favor, notifíquelo inmediatamente y remita el mensaje
> original
> > a la dirección de correo electrónico indicada. Cualquier copia, uso o
> > distribución no autorizados de esta comunicación queda estrictamente
> > prohibida.
> >
> > CONFIDENTIALITY NOTICE: This e-mail and the accompanying document(s) may
> > contain confidential information which is privileged and intended only
> for
> > the individual or entity to whom they are addressed. If you are not the
> > intended recipient, you are hereby notified that any disclosure, copying,
> > distribution or use of this e-mail and/or accompanying document(s) is
> > strictly prohibited. If you have received this e-mail in error, please
> > immediately notify the sender at the above e-mail address.
> >
>

[KDL] Future plans: Collada import and constraint specification

On Sun, 22 Nov 2009, Adolfo Rodríguez Tsouroukdissian wrote:

> From a post in another mailing list [1] I got news that there are plans of adding
> Collada-based input to KDL, for describing the kinematics and dynamics of chains/trees.
> I've been looking into the Collada 1.5 specs lately and the idea of having Collada-based
> persistent storage seems very appealing.

It is! It would be stupid _not_ to use Collada 1.5 :-)

> I also read that there are plans for incorporating constraint-based solvers into KDL. Does
> this refer to iTASC, and more specifically, to the implementation that is currently being
> incorporated into the Blender game engine?.

Yes. (The Blender code is somewhat independent, because Blender
requires/provides another infrastructure than RTT...)

> On this same subject, do your plans also cover
> representing constraints with the Collada standard?.
The standard does not help much in this respect: we will have to define our
own semantic tags for constraints...

> If so, I'm wondering if Collada is
> expressive enough to describe the scenarios that your constraint solvers admit. For
> example, I have found no way of expressing constraint hierarchies other than resorting to
> the <extra> element.
That's right, I think.

>
> Thanks in advance for feeding my curiosity!
We would be happy to start working together on this topic!

Herman

> Adolfo.
>
> [1] ROS users:http://sourceforge.net/mailarchive/forum.php?thread_name=398e6e70911200801qbda13d1v7e646a
> 7c6cccdbad%40mail.gmail.com&forum_name=ros-users
>
> --
> Adolfo Rodríguez Tsouroukdissian, Ph. D.
>
> Robotics engineer
> PAL ROBOTICS S.L
> http://www.pal-robotics.com
> Tel. +34.93.414.53.47
> Fax.+34.93.209.11.09
> AVISO DE CONFIDENCIALIDAD: Este mensaje y sus documentos adjuntos, pueden contener
> información privilegiada y/o confidencial que está dirigida exclusivamente a su
> destinatario. Si usted recibe este mensaje y no es el destinatario indicado, o el empleado
> encargado de su entrega a dicha persona, por favor, notifíquelo inmediatamente y remita el
> mensaje original a la dirección de correo electrónico indicada. Cualquier copia, uso o
> distribución no autorizados de esta comunicación queda estrictamente prohibida.
>
> CONFIDENTIALITY NOTICE: This e-mail and the accompanying document(s) may contain
> confidential information which is privileged and intended only for the individual or
> entity to whom they are addressed.  If you are not the intended recipient, you are hereby
> notified that any disclosure, copying, distribution or use of this e-mail and/or
> accompanying document(s) is strictly prohibited.  If you have received this e-mail in
> error, please immediately notify the sender at the above e-mail address.
>
>

--
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<http://people.mech.kuleuven.be/~bruyninc> Tel: +32 16 328056
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