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<TITLE>AW: [ros-users] robot_state_publisher with joint_states in different messages does not compute tf for all joints</TITLE>
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<P><FONT SIZE=2>Hi,<BR>
<BR>
what's the reason/drawback for not having one robot_state_publisher and one urdf that can deal with multiple joint_states messages for a serial kinematic chain? ...which is, at least for me, the intuitive understanding of a "global" /joint_states topic and a "global" urdf description for the whole robot. Why dividing it into multiple subsystems?<BR>
<BR>
Regards,<BR>
Florian<BR>
<BR>
<BR>
-----Ursprüngliche Nachricht-----<BR>
Von: ros-users-bounces@code.ros.org im Auftrag von David Lu!!<BR>
Gesendet: Mo 22.11.2010 14:45<BR>
An: User discussions<BR>
Betreff: Re: [ros-users] robot_state_publisher with joint_states in different messages does not compute tf for all joints<BR>
<BR>
This is the intended behavior. The standard approach to fixing it is to<BR>
create a node that merges the two JointState messages. Alternatively, you<BR>
could use two separate URDF and two separate robot_state_publishers.<BR>
<BR>
-David!!<BR>
<BR>
On Mon, Nov 22, 2010 at 6:44 AM, Weißhardt, Florian <<BR>
Florian.Weisshardt@ipa.fraunhofer.de> wrote:<BR>
<BR>
> Dear ros users,<BR>
><BR>
><BR>
><BR>
> probably we figured out a bug in the robot_state_publisher (or are not<BR>
> using it correctly):<BR>
><BR>
><BR>
><BR>
> We are running a robot_state_publisher subscribed to the /joint_states<BR>
> topic and using a urdf robot_description. The transformation from<BR>
> joint_states with urdf to tf transformations works only if<BR>
><BR>
> a) the joint information for the whole kinematic chain is published<BR>
> in one joint_states message or<BR>
><BR>
> b) at least there are no joints connected to a serial chain and<BR>
> published in different joint_states messages.<BR>
><BR>
><BR>
><BR>
> In our case e.g. there is a gripper attached to an arm. Both have rotary<BR>
> joints defined and are publishing joint_states in two different joint_states<BR>
> messages, but tf can only be computed for the arm, not for the gripper.<BR>
><BR>
><BR>
><BR>
> Is this a known behaviour (bug?) or are we missing something?<BR>
><BR>
><BR>
><BR>
> Best regards,<BR>
><BR>
> Florian<BR>
><BR>
><BR>
><BR>
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> ros-users@code.ros.org<BR>
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><BR>
><BR>
<BR>
</FONT>
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