Add a namespaced example (#457) (#461)

Co-authored-by: Christoph Fröhlich <[email protected]>

doc/index.rst

@@ -276,6 +276,18 @@ When the Gazebo world is launched you can run some of the following commands to
   ros2 run ign_ros2_control_demos example_tricycle_drive
   ros2 run ign_ros2_control_demos example_ackermann_drive
 
+To demonstrate the setup of a namespaced robot, run
+
+.. code-block:: shell
+
+  ros2 launch ign_ros2_control_demos diff_drive_example_namespaced.launch.py
+
+which will launch a diff drive robot within the namespace ``r1``.
+
+.. note::
+
+  The ros2_control settings for the controller_manager and the controller defined in ``diff_drive_controller.yaml`` use wildcards to match all namespaces.
+
 Gripper
 -----------------------------------------------------------
 

ign_ros2_control_demos/config/diff_drive_controller_velocity.yaml → ign_ros2_control_demos/config/diff_drive_controller.yaml

@@ -1,4 +1,4 @@
-controller_manager:
+/**/controller_manager:
   ros__parameters:
     update_rate: 100  # Hz
 
@@ -8,7 +8,7 @@ controller_manager:
     diff_drive_base_controller:
       type: diff_drive_controller/DiffDriveController
 
-diff_drive_base_controller:
+/**/diff_drive_base_controller:
   ros__parameters:
     left_wheel_names: ["left_wheel_joint"]
     right_wheel_names: ["right_wheel_joint"]

ign_ros2_control_demos/launch/diff_drive_example_namespaced.launch.py

@@ -0,0 +1,116 @@
+# Copyright 2024 Open Source Robotics Foundation, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import os
+
+from ament_index_python.packages import get_package_share_directory
+
+from launch import LaunchDescription
+from launch.actions import DeclareLaunchArgument, IncludeLaunchDescription
+from launch.actions import RegisterEventHandler
+from launch.event_handlers import OnProcessExit
+from launch.launch_description_sources import PythonLaunchDescriptionSource
+from launch.substitutions import Command, FindExecutable, LaunchConfiguration, PathJoinSubstitution
+
+from launch_ros.actions import Node
+from launch_ros.substitutions import FindPackageShare
+
+
+def generate_launch_description():
+    # Launch Arguments
+    use_sim_time = LaunchConfiguration('use_sim_time', default=True)
+
+    # Get URDF via xacro
+    robot_description_content = Command(
+        [
+            PathJoinSubstitution([FindExecutable(name='xacro')]),
+            ' ',
+            PathJoinSubstitution(
+                [FindPackageShare('ign_ros2_control_demos'),
+                 'urdf', 'test_diff_drive.xacro.urdf']
+            ),
+            ' ',
+            'namespace:=r1',
+        ]
+    )
+    robot_description = {'robot_description': robot_description_content}
+
+    node_robot_state_publisher = Node(
+        package='robot_state_publisher',
+        executable='robot_state_publisher',
+        namespace='r1',
+        output='screen',
+        parameters=[robot_description, {'use_sim_time': use_sim_time}],
+    )
+
+    ignition_spawn_entity = Node(
+        package='ros_gz_sim',
+        executable='create',
+        namespace='r1',
+        output='screen',
+        arguments=['-topic', 'robot_description',
+                   '-name', 'diff_drive',
+                   '-allow_renaming', 'true'],
+    )
+
+    joint_state_broadcaster_spawner = Node(
+        package='controller_manager',
+        executable='spawner',
+        arguments=[
+            'joint_state_broadcaster',
+            '-c', '/r1/controller_manager'
+            ],
+    )
+    diff_drive_base_controller_spawner = Node(
+        package='controller_manager',
+        executable='spawner',
+        arguments=[
+            'diff_drive_base_controller',
+            '-c', '/r1/controller_manager'
+            ],
+    )
+
+    # Bridge
+    bridge = Node(
+        package='ros_gz_bridge',
+        executable='parameter_bridge',
+        arguments=['/clock@rosgraph_msgs/msg/Clock[ignition.msgs.Clock'],
+        output='screen'
+    )
+
+    return LaunchDescription([
+        bridge,
+        # Launch gazebo environment
+        IncludeLaunchDescription(
+            PythonLaunchDescriptionSource(
+                [os.path.join(get_package_share_directory('ros_ign_gazebo'),
+                              'launch', 'ign_gazebo.launch.py')]),
+            launch_arguments=[('gz_args', [' -r -v 4 empty.sdf'])]),
+        RegisterEventHandler(
+            event_handler=OnProcessExit(
+                target_action=ignition_spawn_entity,
+                on_exit=[
+                          joint_state_broadcaster_spawner,
+                          diff_drive_base_controller_spawner
+                        ],
+            )
+        ),
+        node_robot_state_publisher,
+        ignition_spawn_entity,
+        # Launch Arguments
+        DeclareLaunchArgument(
+            'use_sim_time',
+            default_value=use_sim_time,
+            description='If true, use simulated clock'),
+    ])

ign_ros2_control_demos/urdf/test_diff_drive.xacro.urdf

@@ -1,5 +1,8 @@
 <?xml version="1.0"?>
 <robot name="diff_drive" xmlns:xacro="http://www.ros.org/wiki/xacro">
+
+  <xacro:arg name="namespace" default="" />
+
   <material name="orange">
     <color rgba="0.8 0.4 0.0 1.0"/>
   </material>
@@ -167,7 +170,10 @@
 
   <gazebo>
     <plugin filename="ign_ros2_control-system" name="ign_ros2_control::IgnitionROS2ControlPlugin">
-      <parameters>$(find ign_ros2_control_demos)/config/diff_drive_controller_velocity.yaml</parameters>
+      <ros>
+        <namespace>$(arg namespace)</namespace>
+      </ros>
+      <parameters>$(find ign_ros2_control_demos)/config/diff_drive_controller.yaml</parameters>
     </plugin>
   </gazebo>