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Gazebo spawn_model hangs (wrong ros namespace) [closed]

asked 2012-08-05 21:52:41 -0500

g.aterido gravatar image

updated 2014-04-20 14:09:32 -0500

ngrennan gravatar image


I have a problem with Gazebo. When I try to launch the model of a robot, I get the following message: loading xml from ros parameter model, but I never get to see the robot in the simulator. The funny thing is that yesterday it loaded the model correctly. Also, when I try to launch some model of Gazebo (a table or something simple) I get the same message and I still see nothing. So, I think that it's not a problem of my model.

Where is the problem? Thanks in advance!

I'm working on Ubuntu 12.04 and fuerte.


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Closed for the following reason the question is answered, right answer was accepted by g.aterido
close date 2012-11-28 21:49:38


With roswtf I get the following error: ERROR Communication with [/empty_world_server] raised an error: ERROR The following nodes should be connected but aren't: * /empty_world_server->/empty_world_server (/clock)

g.aterido gravatar image g.aterido  ( 2012-08-05 23:14:28 -0500 )edit

With roslaunch gazebo_worlds empty_world_paused.launch I dont have this problem... Any clue?

g.aterido gravatar image g.aterido  ( 2012-08-06 00:14:29 -0500 )edit

I have the same problem on a machine with ubuntu ludid and latest fuerte from debs.

Georg gravatar image Georg  ( 2012-08-06 04:08:00 -0500 )edit

Hi g.sterido, can you update the title of this question to something more specific, e.g. "Gazebo spawn_model hangs (wrong ros namespace)" or similar? Thanks.

hsu gravatar image hsu  ( 2012-08-07 06:27:43 -0500 )edit

Title updated! Thanks for the advice ;)

g.aterido gravatar image g.aterido  ( 2012-08-07 20:13:16 -0500 )edit

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answered 2012-08-06 05:19:31 -0500

Georg gravatar image


for a reason that I do not really understand, it helps to name the node "gazebo" instead of "empty_world_server". I changed that after comparing empty_world.launch and empty_world_paused.launch!



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Thanks! That works perfectly!

g.aterido gravatar image g.aterido  ( 2012-08-06 20:20:29 -0500 )edit

answered 2012-08-06 05:48:36 -0500

hsu gravatar image

A recent fix to pass through command line arguments to the ros node initialized within gazebo exposes this problem; by correctly namespacing the gazebo node with the name declared in the launch script. The spawn_model script defaults to look for gazebo services under /gazebo/ namespace, and thus fails and the gazebo node operating under /empty_world_server/(spawn_urdf_model, etc.).

The fix you suggested above is valid. Alternatively, one could also pass the additional commandline argument of gazebo_namespace to the spawn_model script, e.g.

rosrun gazebo spawn_model -gazebo_namespace empty_world_server -...
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Thanks for the explanation! I would suggest to modify the standard world files in gazebo_worlds to be consistent.Best,

Georg gravatar image Georg  ( 2012-08-06 06:11:29 -0500 )edit

@Greg thanks for the suggestion, they should all be consistent by 1.6.13. though in 1.6.12, one of them is still broken (empty_world_throttled.launch).

hsu gravatar image hsu  ( 2012-08-06 06:51:01 -0500 )edit

Thanks! I thought that my computer was going crazy. Regards

g.aterido gravatar image g.aterido  ( 2012-08-06 20:23:46 -0500 )edit

These extra arguments can be put like this no? <node name="youbot_gazebo_model" pkg="gazebo" type="spawn_model" args="-gazebo_namespace youbot_gazebo_model -urdf -param robot_description -model youBot -x 0.0 -y 0.0 -z 0.1" respawn="false" output="screen" /> I still don't see anything on my screen...

NickVT gravatar image NickVT  ( 2012-08-07 06:12:15 -0500 )edit

I can't change the name to gazebo, since I have already a node like that: <node name="gazebo" pkg="gazebo" type="gazebo" args="$(find gazebo_worlds)/worlds/" respawn="false" output="screen"></node>

NickVT gravatar image NickVT  ( 2012-08-07 06:15:55 -0500 )edit

@NickVT you should remove "-gazebo_namespace youbot_gazebo_model" from your "spawn_model" node since your gazebo node is already namespaced under the default namespace that spawn_model looks for (i.e. "/gazebo").

hsu gravatar image hsu  ( 2012-08-07 06:31:41 -0500 )edit

Hi John, without the namespace was the original situation: but Gazebo doesn't come up, there are no errors: spawn status: successfully spawned model [youbot_gazebo_model-3] process has finished cleanly Service [/gazebo/set_physics_properties] is now available. Starting to spin physics dynamic...

NickVT gravatar image NickVT  ( 2012-08-08 02:30:56 -0500 )edit

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Asked: 2012-08-05 21:52:41 -0500

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Last updated: Aug 07 '12