Multiple dimensions

On Mon, Aug 31, 2015 at 12:42 PM, <antoine [dot] rennuit [..] ...
> wrote:

> Hello Adolfo,
>
> When you say "Three vector ports (pos, vel,acc) is a good compromise as you
> don't have to
> develop a new typekit" is this because you mean to use data of type vector
> which is already built-in?
>

Yes.

>
> Also when you write "you could also consider adding a timestamp that
> downstream
> components might find useful", you mean it is useful for non-periodic data
> generation or you also see a use case for this timestamp in case of
> periodic
> data?
>

The data acquisition time can be useful for different things. You could use
it for synchronizing with other data streams, or interpolation (like ROS'
tf). You could also trigger error states if data is older than expected
(data acquisition time != data reception time). If your pos,vel,acc data is
acquired at the same time, it could be convenient to time-stamp the whole
data structure. This is slightly off-topic, as it's not really related to
the original question.

Adolfo.

> Thanks,
>
> Antoine.
> --
> Orocos-Users mailing list
> Orocos-Users [..] ...
> http://lists.mech.kuleuven.be/mailman/listinfo/orocos-users
>

RE : Multiple dimensions

Your answer is clear, thanks a lot!

-------- Message d'origine --------
De : Adolfo Rodríguez Tsouroukdissian <adolfo [dot] rodriguez [..] ...>
Date : 31/08/2015 16:35 (GMT+01:00)
À : Antoine Rennuit <antoine [dot] rennuit [..] ...>
Cc : orocos-users <orocos-users [..] ...>
Objet : Re: [Orocos-users] Multiple dimensions

On Mon, Aug 31, 2015 at 12:42 PM, <antoine [dot] rennuit [..] ...<mailto:antoine [dot] rennuit [..] ...>> wrote:
Hello Adolfo,

When you say "Three vector ports (pos, vel,acc) is a good compromise as you
don't have to
develop a new typekit" is this because you mean to use data of type vector
which is already built-in?

Yes.

Also when you write "you could also consider adding a timestamp that
downstream
components might find useful", you mean it is useful for non-periodic data
generation or you also see a use case for this timestamp in case of periodic
data?

The data acquisition time can be useful for different things. You could use it for synchronizing with other data streams, or interpolation (like ROS' tf). You could also trigger error states if data is older than expected (data acquisition time != data reception time). If your pos,vel,acc data is acquired at the same time, it could be convenient to time-stamp the whole data structure. This is slightly off-topic, as it's not really related to the original question.

Adolfo.

Thanks,

Antoine.
--
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Orocos-Users [..] ...<mailto:Orocos-Users [..] ...>
http://lists.mech.kuleuven.be/mailman/listinfo/orocos-users

--
Adolfo Rodríguez Tsouroukdissian
Senior robotics engineer
adolfo [dot] rodriguez [..] ...<mailto:adolfo [dot] rodriguez [..] ...>
http://www.pal-robotics.com<http://www.pal-robotics.com/>

PAL ROBOTICS S.L
c/ Pujades 77-79, 4º4ª
08005 Barcelona, Spain.
Tel. +34.93.414.53.47
Fax.+34.93.209.11.09
Skype: adolfo.pal-robotics
Facebook<http://www.facebook.com/palrobotics1> - Twitter<http://twitter.com/#%21/palrobotics> - PAL Robotics YouTube Channel<http://www.youtube.com/user/PALRobotics>

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.

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Multiple dimensions

2015-08-31 16:35 GMT+02:00 Adolfo Rodríguez Tsouroukdissian
<adolfo [dot] rodriguez [..] ...>:
>
>
> On Mon, Aug 31, 2015 at 12:42 PM,
> <antoine [dot] rennuit [..] ...> wrote:
>>
>> Hello Adolfo,
>>
>> When you say "Three vector ports (pos, vel,acc) is a good compromise as
>> you
>> don't have to
>> develop a new typekit" is this because you mean to use data of type vector
>> which is already built-in?
>
>
> Yes.
Unfortunately, this is not always a winning approach.
Sending only a vector of positions (or velocities, or acc) leads into
a bookeeping issue (to which joint the position at the index 'i'
refers to?).
Some people (ROS-community) attempt to solve that by adding a "name"
vector of strings (see
<http://docs.ros.org/api/sensor_msgs/html/msg/JointState.html> ), but
this approach fails too, since there is no guarantee that the position
ad index 'i' corresponds to the joint name at index 'i'. (In fact it
is a vector of _unordered_ values, while you expect an ordered list).
In short, there are many assumptions you implicitly take by doing so -
be aware of these!

Cheers,
- Enea

>>
>>
>> Also when you write "you could also consider adding a timestamp that
>> downstream
>> components might find useful", you mean it is useful for non-periodic data
>> generation or you also see a use case for this timestamp in case of
>> periodic
>> data?
>
>
> The data acquisition time can be useful for different things. You could use
> it for synchronizing with other data streams, or interpolation (like ROS'
> tf). You could also trigger error states if data is older than expected
> (data acquisition time != data reception time). If your pos,vel,acc data is
> acquired at the same time, it could be convenient to time-stamp the whole
> data structure. This is slightly off-topic, as it's not really related to
> the original question.
>
> Adolfo.
>
>>
>> Thanks,
>>
>> Antoine.
>> --
>> Orocos-Users mailing list
>> Orocos-Users [..] ...
>> http://lists.mech.kuleuven.be/mailman/listinfo/orocos-users
>
>
>
>
> --
> Adolfo Rodríguez Tsouroukdissian
> Senior robotics engineer
> adolfo [dot] rodriguez [..] ...
> http://www.pal-robotics.com
>
> PAL ROBOTICS S.L
> c/ Pujades 77-79, 4º4ª
> 08005 Barcelona, Spain.
> Tel. +34.93.414.53.47
> Fax.+34.93.209.11.09
> Skype: adolfo.pal-robotics
> Facebook - Twitter - PAL Robotics YouTube Channel
>
> 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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> Orocos-Users [..] ...
> http://lists.mech.kuleuven.be/mailman/listinfo/orocos-users
>

RE : Multiple dimensions

Ha! This is interesting to keep in mind indeed! Thanks a lot.

-------- Message d'origine --------
De : Enea Scioni <scnnee [..] ...>
Date : 31/08/2015 16:47 (GMT+01:00)
À : Adolfo Rodríguez Tsouroukdissian <adolfo [dot] rodriguez [..] ...>
Cc : Antoine Rennuit <antoine [dot] rennuit [..] ...>, orocos-users <orocos-users [..] ...>
Objet : Re: [Orocos-users] Multiple dimensions

2015-08-31 16:35 GMT+02:00 Adolfo Rodríguez Tsouroukdissian
<adolfo [dot] rodriguez [..] ...>:
>
>
> On Mon, Aug 31, 2015 at 12:42 PM,
> <antoine [dot] rennuit [..] ...> wrote:
>>
>> Hello Adolfo,
>>
>> When you say "Three vector ports (pos, vel,acc) is a good compromise as
>> you
>> don't have to
>> develop a new typekit" is this because you mean to use data of type vector
>> which is already built-in?
>
>
> Yes.
Unfortunately, this is not always a winning approach.
Sending only a vector of positions (or velocities, or acc) leads into
a bookeeping issue (to which joint the position at the index 'i'
refers to?).
Some people (ROS-community) attempt to solve that by adding a "name"
vector of strings (see
<http://docs.ros.org/api/sensor_msgs/html/msg/JointState.html> ), but
this approach fails too, since there is no guarantee that the position
ad index 'i' corresponds to the joint name at index 'i'. (In fact it
is a vector of _unordered_ values, while you expect an ordered list).
In short, there are many assumptions you implicitly take by doing so -
be aware of these!

Cheers,
- Enea

>>
>>
>> Also when you write "you could also consider adding a timestamp that
>> downstream
>> components might find useful", you mean it is useful for non-periodic data
>> generation or you also see a use case for this timestamp in case of
>> periodic
>> data?
>
>
> The data acquisition time can be useful for different things. You could use
> it for synchronizing with other data streams, or interpolation (like ROS'
> tf). You could also trigger error states if data is older than expected
> (data acquisition time != data reception time). If your pos,vel,acc data is
> acquired at the same time, it could be convenient to time-stamp the whole
> data structure. This is slightly off-topic, as it's not really related to
> the original question.
>
> Adolfo.
>
>>
>> Thanks,
>>
>> Antoine.
>> --
>> Orocos-Users mailing list
>> Orocos-Users [..] ...
>> http://lists.mech.kuleuven.be/mailman/listinfo/orocos-users
>
>
>
>
> --
> Adolfo Rodríguez Tsouroukdissian
> Senior robotics engineer
> adolfo [dot] rodriguez [..] ...
> http://www.pal-robotics.com
>
> PAL ROBOTICS S.L
> c/ Pujades 77-79, 4º4ª
> 08005 Barcelona, Spain.
> Tel. +34.93.414.53.47
> Fax.+34.93.209.11.09
> Skype: adolfo.pal-robotics
> Facebook - Twitter - PAL Robotics YouTube Channel
>
> 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.
>
> --
> Orocos-Users mailing list
> Orocos-Users [..] ...
> http://lists.mech.kuleuven.be/mailman/listinfo/orocos-users
>