Hi, it looks like the /gazebo node (rosnode info /gazebo) has subscribed to a topic (/cmd_vel) that any node publishes (yet) ...

Questions :

  • How do you know how the /gazebo node is created ?
  • In my local install (roslaunch turtlebot_gazebo turtlebot_world.launch) the /gazebo node doesn't subscribe to any /cmd_vel topic , how do you do that ?

Thank you very much,

asked 09 Jan '18, 13:32

mscavazzin's gravatar image

accept rate: 0%

Hi @mscavazzin,

if you check "turtlebot_world.launch" you can see that this launch file probably includes another launch files. Following the includes you will see that at some point the "empty_world.launch" from the "gazebo_ros" package will be included.

If you check the content of empty_world.launch, you will see that the "gazebo" node is launched.

You can see the content of that file using the command below:

roscat gazebo_ros empty_world.launch

Regarding to the "/cmd_vel" topic, "gazebo" itself doesn't subscribe to that topic. But in Gazebo you can load plugins. These plugins can do anything. In this case, the ".world" that is loaded in gazebo is telling gazebo to load a specific plugin.

More details about Gazebo Plugins can be found on this page: http://gazebosim.org/tutorials?tut=ros_gzplugins


permanent link

answered 09 Jan '18, 21:37

ralves%40theconstructsim.com's gravatar image

ralves@theco... ♦♦
accept rate: 48%


I think I figured that out, the cmd_vel topic is defined in kobuki_gazebo.urdf.xacro Thanks.

(10 Jan '18, 10:30) mscavazzin
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question asked: 09 Jan '18, 13:32

question was seen: 435 times

last updated: 10 Jan '18, 10:30

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