Hi Ugo,
I just tried running your xml file through an xml validator (
www.xmlvalidation.com). I'm getting an error:
*55:** **8** **The string "--" is not permitted within comments.*
*
*
Maybe this is causing robot state publisher to fail quietly.
Vijay
On Wed, Apr 7, 2010 at 3:08 AM, Ugo Cupcic <
ugo@shadowrobot.com> wrote:
> Wim,
>
> The urdf model which doesn't work contained two links and a joint. I tried
> it once more and I don't get a warning in the rxconsole. Still the
> robot_state_publisher didn't subscribe to the /joint_states topic.
>
> The dummy.xml file I attached is my simplified urdf model that doesn't
> work. I have a more complete urdf model which works fine.
>
> Cheers,
>
> Ugo
>
>
> Wim Meeussen wrote:
>
>> Ugo,
>>
>> I figured it out. My urdf model didn't have the same number of joints as
>>> my published joint_states messages.
>>>
>>
>> I don't think this was your problem. The robot state publisher does
>> not care about additional/missing joints in the joint_states message.
>>
>>
>> rostopic info /joint_states
>>> Type: sensor_msgs/JointState
>>> Publishers:
>>> * /shadowhand_publisher (http://ulster:35258/)
>>> Subscribers: None
>>>
>>
>> The output above shows the problem: no node is subscribed to the
>> joint_states topic. So the robot state publisher is not receiving any
>> messages. This should only happen when you give the robot state
>> publisher a urdf with no or only one link. In that case, the robot
>> state publisher couldn't possible publish anything, and it therefore
>> does not subscribe to the joint_states topic.
>>
>> But, you should have seen a warning in 'rxconsole'. It should have
>> shown either "Robot state publisher got an empty tree and cannot
>> publish any state to tf" or "Robot state publisher got a tree with
>> only one segment and cannot publish any state to tf". After it shows
>> this warning, the robot state publisher just sits there, unable to do
>> anything. I guess that is quite a confusing state. We had a discussion
>> about this here <https://code.ros.org/trac/ros-pkg/ticket/3224>. Feel
>> free to add comments based on your experience with the robot state
>> publisher.
>>
>> Wim
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> --
>> Wim Meeussen
>> Willow Garage Inc.
>> <http://www.willowgarage.com)
>> _______________________________________________
>> ros-users mailing list
>> ros-users@code.ros.org
>> https://code.ros.org/mailman/listinfo/ros-users
>>
>>
>
> --
> Ugo Cupcic | Shadow Robot Company | ugo@shadowrobot.com
> Software Engineer 251 Liverpool Road
> need a Hand? London N1 1LX | +44 20 7700 2487
> http://www.shadowrobot.com/hand/ @shadowrobot
>
>
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