kdl::parser
| Submitted by shashank sharma on Sat, 2011-03-05 19:52 |
Hi
I have parsed a URDF model of my robot ( URDF includes joint limits ) via
KDL parser to build a kdl::chain.
This chain I want to use for doing inverse position kinematic solving using
the KDL::ChainIkSolverPos_NR_JL<http://people.mech.kuleuven.be/~orocos/pub/devel/kdl/latest/api/html/classKDL_1_1ChainIkSolverPos__NR__JL.html>
class.
This class requires joint limits. Now is it possible somehow to extract
these values (joint limits from urdf) using the parser? Is there a better
way to do it than hardcoding (defining it specifically) it?
Regards
Shashank
kdl::parser
Shashank, (CC to ros-users)
> I have parsed a URDF model of my robot ( URDF includes joint limits ) via
> KDL parser to build a kdl::chain.
> This chain I want to use for doing inverse position kinematic solving using
> the KDL::ChainIkSolverPos_NR_JL class.
> This class requires joint limits. Now is it possible somehow to extract
> these values (joint limits from urdf) using the parser? Is there a better
> way to do it than hardcoding (defining it specifically) it?
A urdf tree contains joint limits, but a kdl tree/chain does not. In
the kdl world the joint limits are not part of the model, but instead
are parameters to some of the solvers. The best way to get access to
the joint limits is by using the urdf parser. You can pass the same
urdf file to both the urdf parser and the kdl parser (internally the
kdl parser uses the urdf parser before it converts the model to a kdl
format). The code api of the urdf model
<http://www.ros.org/doc/api/urdf/html/classurdf_1_1Model.html> should
help you find the joint limits.
Hope this helps,
Wim
kdl::parser
Hello Wim,
Thanks for the suggestion.
Regards
Shashank
On Sat, Mar 5, 2011 at 10:23 PM, Wim Meeussen <meeussen [..] ...>wrote:
> Shashank, (CC to ros-users)
>
> > I have parsed a URDF model of my robot ( URDF includes joint limits ) via
> > KDL parser to build a kdl::chain.
> > This chain I want to use for doing inverse position kinematic solving
> using
> > the KDL::ChainIkSolverPos_NR_JL class.
> > This class requires joint limits. Now is it possible somehow to extract
> > these values (joint limits from urdf) using the parser? Is there a better
> > way to do it than hardcoding (defining it specifically) it?
>
> A urdf tree contains joint limits, but a kdl tree/chain does not. In
> the kdl world the joint limits are not part of the model, but instead
> are parameters to some of the solvers. The best way to get access to
> the joint limits is by using the urdf parser. You can pass the same
> urdf file to both the urdf parser and the kdl parser (internally the
> kdl parser uses the urdf parser before it converts the model to a kdl
> format). The code api of the urdf model
> <http://www.ros.org/doc/api/urdf/html/classurdf_1_1Model.html> should
> help you find the joint limits.
>
> Hope this helps,
>
> Wim
>
>
>
>
> --
> --
> Wim Meeussen
> Willow Garage Inc.
> <http://www.willowgarage.com)
>