gazebo_ros2_control Plugin Error

[NoobiesDoobies]

Hi, I'm using Ubuntu 22.04 with ros-humble and gazebo-classic. When I use gazebo_ros2_control/GazeboSystem plugin for my ros2_control framework, I get this error:

[ros2_control_node-2] what(): According to the loaded plugin descriptions the class gazebo_ros2_control/GazeboSystem with base class type hardware_interface::SystemInterface does not exist. Declared types are diffbot_control/DiffBotSystemHardware fake_components/GenericSystem mock_components/GenericSystem test_hardware_components/TestSystemCommandModes test_hardware_components/TestTwoJointSystem

When I launch it using my own ros2_control plugin, it works. I made my own plugin (The diffbot_control/DiffBotSystemHardware) by following one of Josh's tutorials (here is my ros2_control hardware interface plugin). It is based on the HardwareInterface::SystemInterface class. However, gazebo_ros2_control seems to not use the same class (?)

This is my control urdf:

<?xml version="1.0"?>
<robot xmlns:xacro="http://www.ros.org/wiki/xacro">

  <xacro:macro name="diffbot_ros2_control" params="name prefix use_mock_hardware">

    <ros2_control name="${name}" type="system">
      <xacro:unless value="${use_mock_hardware}">
        <hardware>
          <plugin>diffbot_control/DiffBotSystemHardware</plugin>
          <param name="example_param_hw_start_duration_sec">0</param>
          <param name="example_param_hw_stop_duration_sec">3.0</param>
          <param name="left_wheel_name">left_wheel_joint</param>
          <param name="right_wheel_name">right_wheel_joint</param>
          <param name="imu_name">mpu_6050</param>
          <param name="loop_rate">30</param>

          <!-- First Arduino for motor command and encoder reading -->
          <param name="device_motor_bridge">
            /dev/serial/by-id/usb-Arduino__www.arduino.cc__0043_557393239373515181E1-if00</param>
          <!-- Second Arduino for IMU reading -->
          <param name="device_imu_bridge">
            /dev/serial/by-id/usb-Arduino__www.arduino.cc__0043_75735353338351E050A1-if00</param>

          <!-- <param name="device">/dev/ttyACM0</param> -->
          <param name="baud_rate">57600</param>
          <param name="timeout_ms">1000</param>
          <param name="enc_counts_per_rev">425</param>
          <param name="imu_calib_timeout_ms">100000</param>
          <param name="pid_p">10</param>
          <param name="pid_d">0</param>
          <param name="pid_i">5</param>
          <param name="pid_o">0</param>

        </hardware>
      </xacro:unless>
      <xacro:if value="${use_mock_hardware}">
        <hardware>
          <plugin>gazebo_ros2_control/GazeboSystem</plugin>
        </hardware>
      </xacro:if>
      <joint name="${prefix}left_wheel_joint">
        <command_interface name="velocity" />
        <state_interface name="position" />
        <state_interface name="velocity" />
      </joint>
      <joint name="${prefix}right_wheel_joint">
        <command_interface name="velocity" />
        <state_interface name="position" />
        <state_interface name="velocity" />
      </joint>

    </ros2_control>

    <xacro:if value="${use_mock_hardware}">
      <plugin filename="ign_ros2_control-system" name="ign_ros2_control::IgnitionROS2ControlPlugin">
        <parameters>$(find slam_bot)/config/diffbot_controllers.yaml</parameters>
      </plugin>
    </xacro:if>

  </xacro:macro>

</robot>

This is my launch file:

import os

from ament_index_python.packages import get_package_share_directory


from launch import LaunchDescription
from launch.actions import IncludeLaunchDescription, TimerAction
from launch.launch_description_sources import PythonLaunchDescriptionSource
from launch.substitutions import Command, LaunchConfiguration, PythonExpression
from launch.actions import RegisterEventHandler, DeclareLaunchArgument
from launch.event_handlers import OnProcessStart

from launch_ros.actions import Node



def generate_launch_description():
    
    package_name='slam_bot' 

    use_ros2_control = LaunchConfiguration('use_ros2_control')

    use_ros2_control_dec = DeclareLaunchArgument(
        'use_ros2_control',
        default_value='true',
        description='Use ros2 control if true'
    )

    tracker_params_sim = os.path.join(get_package_share_directory(package_name),'config','ball_tracker_params_sim.yaml')
    tracker_params_robot = os.path.join(get_package_share_directory(package_name),'config','ball_tracker_params_robot.yaml')


    robot_spawner = IncludeLaunchDescription(
                PythonLaunchDescriptionSource([os.path.join(
                    get_package_share_directory(package_name),'launch','robot_spawner.launch.py'
                )]), launch_arguments={'sim_mode': 'true', 'use_ros2_control': use_ros2_control}.items()
    )

    joystick = IncludeLaunchDescription(
                PythonLaunchDescriptionSource([os.path.join(
                    get_package_share_directory(package_name),'launch','joystick.launch.py'
                )])
    )


    # twist_mux_params = os.path.join(get_package_share_directory(package_name),'config','twist_mux.yaml')
    # twist_mux = Node(
    #         package="twist_mux",
    #         executable="twist_mux",
    #         parameters=[twist_mux_params],
    #         remappings=[('/cmd_vel_out','/diff_cont/cmd_vel_unstamped')]
    #     )

    


    robot_description = Command(['ros2 param get --hide-type /robot_state_publisher robot_description'])

    controller_params_file = os.path.join(get_package_share_directory(package_name),'config','diffbot_controllers.yaml')

    controller_manager = Node(
        package="controller_manager",
        executable="ros2_control_node",
        parameters=[{'robot_description': robot_description},
                    controller_params_file],
        output="both",
        remappings=[
            ("~/robot_description", "/robot_description"),
        ],
    )

    delayed_controller_manager = TimerAction(period=1.0, actions=[controller_manager])

    diff_drive_spawner = Node(
        package="controller_manager",
        executable="spawner",
        arguments=["diffbot_base_controller"],
    )

    delayed_diff_drive_spawner = RegisterEventHandler(
        event_handler=OnProcessStart(
            target_action=controller_manager,
            on_start=[diff_drive_spawner],
        )
    )

    joint_broad_spawner = Node(
        package="controller_manager",
        executable="spawner",
        arguments=["joint_state_broadcaster"],
    )

    delayed_joint_broad_spawner = RegisterEventHandler(
        event_handler=OnProcessStart(
            target_action=controller_manager,
            on_start=[joint_broad_spawner],
        )
    )
    gazebo_params_file = os.path.join(get_package_share_directory(package_name),'config','gazebo_params.yaml')

    # Include the Gazebo launch file, provided by the gazebo_ros package
    gazebo = IncludeLaunchDescription(
                PythonLaunchDescriptionSource([os.path.join(
                    get_package_share_directory('gazebo_ros'), 'launch', 'gazebo.launch.py')]),
                    launch_arguments={'extra_gazebo_args': '--ros-args --params-file ' + gazebo_params_file}.items()
             )


    # Launch them all!
    return LaunchDescription([
        use_ros2_control_dec,
        robot_spawner,
        gazebo,
        # joystick,
        # twist_mux,
        delayed_controller_manager,
        delayed_diff_drive_spawner,
        delayed_joint_broad_spawner
    ])

Can anybody help me resolve this issue? I have made sure that the gazebo-ros2-control package is installed by running
sudo apt install ros-humble-gazebo-ros2-control

Thanks !!