Hi,

You need parenthesis around your find command.  the $( ..) triggers an
escape for the launch file interpreter and tells it to execute the
commands inside.  It should look something like this:

<param name="robot_description"
 command="cat $(find learning_urdf)/my_urdf.xml" />

Good luck,
Adam

On Fri, Apr 30, 2010 at 4:13 AM, shayan sengupta <shayanfennec@gmail.com> wrote:
>
> hi
>
> I have created an urdf package for my robot refering the urdf tutorials and its working as expected.I have included a visual tag to the top link of my robot so that i can visualize it on rviz.I tried creating a launch file using following set of instruction
>
> <launch>
> <param name="robot_description" command="cat $(find packagename)/model.xml" />
>
> </launch>
>
> but when i try to launch this file i get invalid parameter tag error
>
>
> Invalid <param> tag: Cannot load command parameter [my_urdf.xml]: command [cat $learning_urdf/my_urdf.xml] returned with code [1].
>
> Param xml is <param command="cat $learning_urdf/my_urdf.xml" name="my_urdf.xml"/>
>
>
> Actually I am not quite sure what give as a parameter name.
>
> so if any one can suggest it would be a great help.
>
> Regards,
> Shayan Sengupta
>
>
>
>
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