This stub is just to sort of report and query whether we are on the right track with using Gazebo in ROS.
Yesterday we wanted to couple ROS Fuerte with Gazebo on Ubuntu 12.04.
We first installed gazebo 1.4 from source and followed this tutorial for ROS integration: http://gazebosim.org/wiki/Tutorials/1.4/ros_enabled_model_plugin. Worked well but now the problem with the tutorial is that the plugin is not a ROS package anymore. After talking to @jhsu he's told me the following:
jhsu: this was an exercise in cmake. We've recently moved drcsim's ros plugins into a cmake subproject using ExternalProject_Add, which seems to work despite the fact that we haven't yet figured out how to make it track dependent file modification and trigger recompile, otherwise seems to be working ok. Using this approach, we will switch back to invoking rosbuild as a ros package directly. On the ros front, the plan is to update simulator_gazebo in Hydro so it does not pull/compile it's own binary, but use a system debian install instead.
We in fact did go back, use pkg-config magic from the tutorial within the ros package for our plugin and were able to build it successfully. The problem however now was that we could not run gazebo from the Gazebo script anymore. This basically also means that
a) we could not run Gazebo as a ROS node anymore and
b) could not conveniently use ROS package file structure anymore. Too many drawback which led us back to the gazebo_simulator ROS stack.
In there we enabled building of Gazebo from source and checked out the deprecated_parser_sdf_1.2_support branch. This one also compiled and run fine (we could run it rosrun for instance) but all of a sudden could not load our robot sdf model anymore. It then turned out that was because GAZEBO_MODEL_PATH was not set by the gazebo_ros_paths_plugin.cpp.
This is our state as of today, tomorrow we will provide the patch for the latter.
@jhsu also said that from ROS Hydro all these issues will go away since Gazebo will become a system dependency. But since we need ROS and Gazebo working today, I would still like to raise couple of questions to help us move forward.
URDF vs SDF: How do you model your robots that are running in simulation as well as in real hardware? Do you maintain both sdf and urdf files?
When using Gazebo in ROS - are we supposed to set any of the
GAZEBO_*environment variables explicitly in bash? Or is everything begin taken care of by the gazebo/scripts/gazebo scripts?GAZEBO_MODEL_PATHis obviously not.Is Gazebo ROS node actually publishing robot's joint_states as needed by the
robot_state_publisher?Is Gazebo currently (branch
deprecated_parser_sdf_1.2_support) running on different computers (e.g. server on one and client on another one)? If yes, is there an example?
Thx, D.
Originally posted by dejanpan on Gazebo Answers with karma: 60 on 2013-02-05
Post score: 2
Original comments
Comment by dejanpan on 2013-02-06:
Nate thanks a lot for your answer, I am sure it will help plenty of people. Sorry for missing on the rosrun and Gazebo publishing joint_states things, I in no case did not want to be misleading. I just wanted to gather whether my current understanding of things was correct. You guys are doing great and I am sure all the changes and muddy waters are for the better. When Gazebo will be factored out of ROS, can you comment on how that is planned to be done?
Comment by dejanpan on 2013-02-06:
I can see how you do something like this with openCV or PCL which are pure libraries and then in ROS you only call their functions, but with Gazebo you will always need to run gzserver and gzclients as separate processes, no?