Ros2 control ang gazebo ignition

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[ROS2 Control + Gazebo Ignition] Issue with loading libgz_ros2_control-system.so

Hi everyone,

I’m using Ubuntu 22.04 (Jammy) with ROS 2 Humble, and I’ve installed Gazebo Ignition (the version released for Humble).

I’m quite new to the ROS ecosystem — and even newer to ros2_control — so I could really use some help.

:white_check_mark: Setup Summary

I installed both versions of the control plugin (gz and ign) since I wasn’t sure which was correct:

libgz_ros2_control-system.so
libign_ros2_control-system.so

In my robot’s URDF, I have the following plugin section:

<gazebo>
  <plugin name="gz_ros2_control::GazeboSystem" filename="libgz_ros2_control-system.so">
    <ros>
      <remapping>tf:=tf</remapping>
      <remapping>tf_static:=tf_static</remapping>
    </ros>
    <parameters>$(find control_bringup)/share/control_bringup/config/xinius_control.yaml</parameters>
  </plugin>
</gazebo>

I’m not 100% sure the plugin line is correct — that’s one of my concerns.

:rocket: Launch File

Here’s the relevant part of my launch.py that starts the robot:

def generate_launch_description():
    pkg_share = FindPackageShare('control_bringup').find('control_bringup')
    urdf_path = os.path.join(pkg_share, 'description', 'Xinius.urdf')
    controller_config = os.path.join(pkg_share, 'config', 'xinius_control.yaml')

    with open(urdf_path, 'r') as infp:
        robot_description_content = infp.read()

    return LaunchDescription([
        Node(
            package='robot_state_publisher',
            executable='robot_state_publisher',
            name='robot_state_publisher',
            parameters=[{'robot_description': robot_description_content}],
            output='screen'
        ),

        Node(
            package='controller_manager',
            executable='ros2_control_node',
            parameters=[
                {'robot_description': robot_description_content},
                controller_config
            ],
            output='screen'
        ),

        ExecuteProcess(
            cmd=['ign', 'gazebo', '-r', 'empty.sdf', '--force-version', '6'],
            output='screen'
        ),
    ])

:cross_mark: Error

When I launch the system and spawn my robot, I get the following error:

[ERROR] [ros2_control_node-2]: process has died [pid 8121, exit code -6, ...]
[ign-3] libEGL warning: MESA-LOADER: failed to open vgem
[ign-3] libEGL warning: NEEDS EXTENSION: falling back to kms_swrast
[ign-3] [Err] [SystemLoader.cc:94] Failed to load system plugin [libgz_ros2_control-system.so] : couldn't find shared library.

:puzzle_piece: Configuration File

Here’s my YAML file, which I believe is correctly formatted:

xinius_geometry:
  ros__parameters:
    wheel_radius: 0.050
    wheels_separation: 0.678
    wheels_separation_multiplier: 1.0
    left_wheel_radius_multiplier: 1.0
    right_wheel_radius_multiplier: 1.0

diff_drive:
  ros__parameters:
    odom_frame_id: odom
    robot_frame_id: base_footprint
    translation_covariance_base: 0.005
    rotation_covariance_base: 0.005
    max_dt: 0.1
    max_delta_wheels: 6.0

:red_question_mark: Questions

  • Is the plugin name/filename correct for ROS 2 Humble with Ignition?
  • Should I be using libign_ros2_control-system.so instead?
  • Could this be a build or install path issue?

Thanks in advance for any help!