[Jazzy] How to set: position_proportional_gain

[firesurfer]

Hi I am looking for a way to set the position_proportional_gain parameter.

According to: #250 it should be possible to be set from a parameter file.
Unfortunately there seems to be no (or I can't find it) documentation on how to provide an additional configuration file for the gz_ros_control node from a launch file.

[firesurfer]

A friendly push :)

[christophfroehlich]

I neither was able to pass ROS arguments to the gz_ros2_control node, I added a parser from the URDF in the linked PR.

[christophfroehlich]

I managed to pass ROS parameters: Just add this to the yaml file passed in the parameters

gz_ros_control:
  ros__parameters:
    position_proportional_gain: 0.5

be aware that the node is called gz_ros_control instead of gz_ros2_control ;)

[firesurfer]

Sorry for the dumb question, but in a launch file. Which component do I need to pass that parameter file, is it the

	start_gazebo_cmd = IncludeLaunchDescription(
		PythonLaunchDescriptionSource(
			os.path.join(pkg_ros_gz_sim, 'launch', 'gz_sim.launch.py')),
		launch_arguments=[('gz_args', [' -r -v 4 empty.sdf']),])

As far as I am aware there is no example that shows how to pass a parameter file.

[christophfroehlich]

I tried the same, and parameters should have wildcard namespace from the launch file -> it did not work.
I have no idea if this is possible, maybe the gz_sim.launch.py does not pass the parameters to gz.

[firesurfer]

I managed to pass ROS parameters: Just add this to the yaml file passed in the parameters

gz_ros_control:
  ros__parameters:
    position_proportional_gain: 0.5

be aware that the node is called gz_ros_control instead of gz_ros2_control ;)

Then I don't understand your answer :D

Or is the PR you linked necessary for that to work ?

[christophfroehlich]

No, the PR is for adding them as parameters in the URDF plugin tag.

Add gz_ros2_control namespace in the yaml file you load into the plugin, like this cart_controller.yaml

<gazebo>
  <plugin filename="libgz_ros2_control-system.so" name="gz_ros2_control::GazeboSimROS2ControlPlugin">
    <parameters>$(find gz_ros2_control_demos)/config/cart_controller.yaml</parameters>
  </plugin>
</gazebo>

They will be passed to the node of gz_ros_control.