Using multiple robots with different namespaces isn't working

[AshBastian]

This is the next problem after solving the update_rate problem #366
Now that I can load my robot into the namespace, I tried to load a second one in the the same simulation (therefore the namespace for the robot). While the robot spawns into the simulation without a problem, the plugins take the namespace of the first robot, regardless of what you define in the xacro.urdf.
I hope I get help as fast as last time.
Here the code with the problem:

1. The launch file:

import os

from ament_index_python.packages import get_package_share_directory

from launch import LaunchDescription
from launch.actions import IncludeLaunchDescription, RegisterEventHandler
from launch.launch_description_sources import PythonLaunchDescriptionSource
from launch_ros.actions import Node
from launch.event_handlers import OnProcessExit

import xacro
import rclpy

def generate_launch_description():
    # Create the launch description and populate
    ld = LaunchDescription()

    bringup_dir = get_package_share_directory('gazebo_simulation')
    pkg_gazebo_ros = get_package_share_directory('gazebo_ros')

    urdf1 = os.path.join(bringup_dir, 'urdf', 'test_cart_position_omni1.xacro.urdf')
    urdf2 = os.path.join(bringup_dir, 'urdf', 'test_cart_position_omni2.xacro.urdf')

    gazebo = IncludeLaunchDescription(
                PythonLaunchDescriptionSource([os.path.join(
                    pkg_gazebo_ros, 'launch'), '/gazebo.launch.py']),
             )
    
    doc1 = xacro.parse(open(urdf1))
    xacro.process_doc(doc1)
    params1 = {'robot_description': doc1.toxml()}

    doc2 = xacro.parse(open(urdf2))
    xacro.process_doc(doc2)
    params2 = {'robot_description': doc2.toxml()}

    remappings = [('/tf', 'tf'),
                  ('/tf_static', 'tf_static')]

    omni1_state_publisher = Node(
        package='robot_state_publisher',
        executable='robot_state_publisher',
        namespace='omni1',
        output='screen',
        parameters=[params1],
        remappings=remappings
        )
    
    omni2_state_publisher = Node(
        package='robot_state_publisher',
        executable='robot_state_publisher',
        namespace='omni2',
        output='screen',
        parameters=[params2],
        remappings=remappings
        )
    
    spawn_omni1 = Node(
            package='gazebo_ros',
            executable='spawn_entity.py',
            namespace='omni1',
            arguments=[
                '-topic', 'robot_description',
                '-entity', 'omni1_robot',
                '-x', '0.0', '-y', '0.0',
                '-z', '1.01', '-Y', '0.0',
                '-unpause',
            ],
            output='screen',
        )
    
    spawn_omni2 = Node(
            package='gazebo_ros',
            executable='spawn_entity.py',
            namespace='omni2',
            arguments=[
                '-topic', 'robot_description',
                '-entity', 'omni2_robot',
                '-x', '1.5', '-y', '10.5',
                '-z', '1.01', '-Y', '0.0',
                '-unpause',
            ],
            output='screen',
        )
    
    # ld.add_action(start_gazebo_server_cmd)
    # ld.add_action(start_gazebo_client_cmd)

    ld.add_action(gazebo)
    
    ld.add_action(omni1_state_publisher)
    ld.add_action(spawn_omni1)

    spawn_omni_event = RegisterEventHandler(
                event_handler=OnProcessExit(
                    target_action=spawn_omni1,
                    on_exit=[omni2_state_publisher,
                             spawn_omni2],
                )
            )

    ld.add_action(spawn_omni_event)
    # ld.add_action(omni2_state_publisher)
    # ld.add_action(spawn_omni2)
    
    
    return ld

2. The urdf: (the namespace in changed according to the name in the launch, because there are 2 nearly identical file for the different namespaces)

<?xml version="1.0" ?>
<robot name="cart">
  <link name="world"/>
  <link name="slideBar">
    <visual>
      <geometry>
        <box size="30 0.05 0.05"/>
      </geometry>
      <origin xyz="0 0 0"/>
      <material name="green">
        <color rgba="0 0.8 .8 1"/>
      </material>
    </visual>
    <inertial>
      <mass value="100"/>
      <inertia ixx="1.0" ixy="0.0" ixz="0.0" iyy="1.0" iyz="0.0" izz="1.0"/>
    </inertial>
  </link>
  <link name="cart">
    <visual>
      <geometry>
        <box size="0.5 0.5 0.2"/>
      </geometry>
      <origin xyz="0 0 0"/>
      <material name="blue">
        <color rgba="0 0 .8 1"/>
      </material>
    </visual>
    <inertial>
      <mass value="1"/>
      <inertia ixx="1.0" ixy="0.0" ixz="0.0" iyy="1.0" iyz="0.0" izz="1.0"/>
    </inertial>
  </link>
  <joint name="world_to_base" type="fixed">
    <origin rpy="0 0 0" xyz="0 0 1"/>
    <parent link="world"/>
    <child link="slideBar"/>
  </joint>
  <joint name="slider_to_cart" type="prismatic">
    <axis xyz="1 0 0"/>
    <origin xyz="0.0 0.0 0.0"/>
    <parent link="slideBar"/>
    <child link="cart"/>
    <limit effort="1000.0" lower="-15" upper="15" velocity="30"/>
    <dynamics damping="0.0" friction="0.0"/>
  </joint>
  <ros2_control name="GazeboSystem" type="system">
    <hardware>
      <plugin>gazebo_ros2_control/GazeboSystem</plugin>
    </hardware>
    <joint name="slider_to_cart">
      <command_interface name="position">
        <param name="min">-15</param>
        <param name="max">15</param>
      </command_interface>
      <state_interface name="position">
        <param name="initial_value">1.0</param>
      </state_interface>
      <state_interface name="velocity"/>
      <state_interface name="effort"/>
    </joint>
  </ros2_control>

  <gazebo>
    <plugin filename="libgazebo_ros2_control.so" name="gazebo_ros2_control">
      <ros>
        <namespace>omni1</namespace>
      </ros>
      <parameters>$(find gazebo_simulation)/models/rs_robot/config/controllers_omni1.yaml</parameters>
    </plugin>
  </gazebo>
</robot>

3. The controllers_omni1.yaml: (Again namespace is change depending on the used namespace)

/omni1/controller_manager:
  ros__parameters:
    update_rate: 1000  # Hz

    joint_state_broadcaster:
      type: joint_state_broadcaster/JointStateBroadcaster

    forward_velocity_controller:
      type: forward_command_controller/ForwardCommandController

/omni1/forward_velocity_controller:
  ros__parameters:
    joints:
      - first_wheel_joint
      - second_wheel_joint
      - third_wheel_joint
      - fourth_wheel_joint
    interface_name: velocity
    command_interfaces:
      - velocity
    state_interfaces:
      - velocity

[AshBastian]

#127 is still the problem here, so you need to comment out the namespace extra part in the gazebo_ros2_control_plugin.cpp