iTaSC vs. WBC

We were wondering what was the main pros and cons when comparing the
whole-body control (WBC) and iTaSC.

Any insights ?

Thanks in advance,
Sylvain

iTaSC vs. WBC

On Tue, Mar 19, 2013 at 11:33 AM, Sylvain Joyeux <sylvain [dot] joyeux [..] ...>wrote:

> We were wondering what was the main pros and cons when comparing the
> whole-body control (WBC) and iTaSC.
>

WBC meaning a specific implementation, or WBC in general?.

I see iTaSC more as something that leverages a WBC solver. iTaSC should
already be able to support inverse kinematics/dynamics (IK/ID) solvers for
whole-body control. IIRC it currently allows for multiple tasks prioritized
by weights and/or strict priorities. That alone allows you to do quite a
lot of whole-body stuff.

One of the more difficult aspects to address in a realtime IK/ID solver
with multiple priority levels are inequality constraints (joint
pos/vel/effort limits, collisions, visibility, ...). The folks at LAAS
(your old home ;-) have done some pretty good work along these lines with
their stack of tasks --SoT-- implementation (paper [1], code [2]).
According to [3] there should be something going on to integrate iTaSC-SoT.
I don't know the current status of this endeavor.

What kind of problem are you trying to solve with whole-body control?.
We'll have somebody looking into [2] in the coming months.

Cheers,

Adolfo.

[1] http://hal.inria.fr/hal-00751924
[2] https://github.com/laas/soth
[3] http://robohow.eu/meetings/first-integration-workshop

> Any insights ?
>
> Thanks in advance,
> Sylvain
> --
> Orocos-Users mailing list
> Orocos-Users [..] ...
> http://lists.mech.kuleuven.be/mailman/listinfo/orocos-users
>

iTaSC vs. WBC

On 03/19/2013 12:26 PM, Adolfo Rodríguez Tsouroukdissian wrote:
>
>
> On Tue, Mar 19, 2013 at 11:33 AM, Sylvain Joyeux
> <sylvain [dot] joyeux [..] ... <mailto:sylvain [dot] joyeux [..] ...>> wrote:
>
> We were wondering what was the main pros and cons when comparing the
> whole-body control (WBC) and iTaSC.
>
>
> WBC meaning a specific implementation, or WBC in general?.
Meaning the stanford WBC implementation
https://github.com/poftwaresatent/stanford_wbc

iTaSC vs. WBC

On Tue, Mar 19, 2013 at 2:06 PM, Sylvain Joyeux <sylvain [dot] joyeux [..] ...>wrote:

> On 03/19/2013 12:26 PM, Adolfo Rodríguez Tsouroukdissian wrote:
>
>
>
> On Tue, Mar 19, 2013 at 11:33 AM, Sylvain Joyeux <sylvain [dot] joyeux [..] ...>wrote:
>
>> We were wondering what was the main pros and cons when comparing the
>> whole-body control (WBC) and iTaSC.
>>
>
> WBC meaning a specific implementation, or WBC in general?.
>
> Meaning the stanford WBC implementation
> https://github.com/poftwaresatent/stanford_wbc
>

The last time I checked the source in detail was about two-three years ago,
but it seems to not have changed much since. The main limitation for me was
that it only dealt with equality constraints.

> --
> Sylvain Joyeux (Dr.Ing.)
> Senior Researcher
>
> Space & Security Robotics
> Underwater Robotics
>
> !!! Achtung, neue Telefonnummer!!!
>
> Standort Bremen:
> DFKI GmbH
> Robotics Innovation Center
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>
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> Fax: +49 (0)421 218-454150
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>
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> -----------------------------------------------------------------------
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>

iTaSC vs. WBC

hi,

On 03/19/2013 02:47 PM, Adolfo Rodríguez Tsouroukdissian wrote:
>
>
> On Tue, Mar 19, 2013 at 2:06 PM, Sylvain Joyeux <sylvain [dot] joyeux [..] ... <mailto:sylvain [dot] joyeux [..] ...>> wrote:
>
> On 03/19/2013 12:26 PM, Adolfo Rodríguez Tsouroukdissian wrote:
>>
>>
>> On Tue, Mar 19, 2013 at 11:33 AM, Sylvain Joyeux <sylvain [dot] joyeux [..] ... <mailto:sylvain [dot] joyeux [..] ...>> wrote:
>>
>> We were wondering what was the main pros and cons when comparing the
>> whole-body control (WBC) and iTaSC.
>>
>>
>> WBC meaning a specific implementation, or WBC in general?.
> Meaning the stanford WBC implementation https://github.com/poftwaresatent/stanford_wbc
>
>
> The last time I checked the source in detail was about two-three years ago, but it seems to not have changed much since. The main limitation for me was that it only dealt
> with equality constraints.

there are some differences, for example:
*WBC uses a single task frame to express their tasks, while iTaSC allows multiple frames to express a task, the feature frames, allowing a structured approach
situations that these extra frames and expressiveness are useful are eg. using cylindrical coordinates when opening a door or complexer when making a sliding contact
between a robot arm and a table for example, where the feature frames allow to express the movement of the contact point
*iTaSC is actively developed, (although you maybe didn't notice that on the orocos.org/itasc website yet), some things for the near future:
**a formal model of task specification (iTaSC DSL)(release before the summer): this will make it far easier to develop itasc applications!
**code upgrades (see devel branch of all itasc stacks)(release before the summer)
**the move of the itasc algorithms to a library (under development)
**integration of SoT (under development together with LAAS-CNRS, first inequality solver integrated that needs some extra code and testing)
some other things on the agenda:
**other options than using VKC's
**fbsched integration

keep posted, more info coming soon!

>
> --
> Sylvain Joyeux (Dr.Ing.)
> Senior Researcher
>
> Space & Security Robotics
> Underwater Robotics
>
> !!! Achtung, neue Telefonnummer!!!
>
> Standort Bremen:
> DFKI GmbH
> Robotics Innovation Center
> Robert-Hooke-Straße 5
> 28359 Bremen, Germany
>
> Phone:+49 (0)421 178-454136 <tel:%2B49%20%280%29421%20178-454136>
> Fax:+49 (0)421 218-454150 <tel:%2B49%20%280%29421%20218-454150>
> E-Mail:robotik [..] ... <mailto:robotik [..] ...>
>
> Weitere Informationen:http://www.dfki.de/robotik
> -----------------------------------------------------------------------
> Deutsches Forschungszentrum fuer Kuenstliche Intelligenz GmbH
> Firmensitz: Trippstadter Straße 122, D-67663 Kaiserslautern
> Geschaeftsfuehrung: Prof. Dr. Dr. h.c. mult. Wolfgang Wahlster
> (Vorsitzender) Dr. Walter Olthoff
> Vorsitzender des Aufsichtsrats: Prof. Dr. h.c. Hans A. Aukes
> Amtsgericht Kaiserslautern, HRB 2313
> Sitz der Gesellschaft: Kaiserslautern (HRB 2313)
> USt-Id.Nr.: DE 148646973
> Steuernummer: 19/673/0060/3
> -----------------------------------------------------------------------
>
>
>
>
> --
> 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
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> 08005 Barcelona, Spain.
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