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mergify[bot]bobbleballsahcorde
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Fix namespacing for multiple instances of gazebo_ros2_control plugin (#181) (#398)
Co-authored-by: ben.holden <[email protected]> Co-authored-by: Christoph Froehlich <[email protected]> (cherry picked from commit 828b5f2) Co-authored-by: Ben Holden <[email protected]> Co-authored-by: Alejandro Hernández Cordero <[email protected]>
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‎doc/index.rst

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@@ -313,6 +313,54 @@ The following is a basic configuration of the controllers:
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.. literalinclude:: ../gazebo_ros2_control_demos/config/cart_controller.yaml
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:language: yaml
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Multiple Namespaces
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-----------------------------------------------------------
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The gazebo_ros2_control plugin can be launched in multiple namespaces. This is useful if it is desired to have multiple robots of the same description running at the same time.
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It is possible to directly define the namespace in the URDF file, as shown below:
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.. code-block:: xml
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<gazebo>
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<plugin name="gazebo_ros2_control" filename="libgazebo_ros2_control.so">
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<parameters> $(arg control_yaml) </parameters>
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<ros>
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<namespace>r1</namespace>
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<remapping>/tf:=tf</remapping>
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<remapping>/tf_static:=tf_static</remapping>
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<remapping>diffdrive_controller/odom:=odom</remapping>
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</ros>
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</plugin>
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</gazebo>
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Where ``r1`` is the namespace associated to the particular instance of the plugin. Please note that the remapping of ``/tf`` and ``/tf_static`` is recommended only if you want to have a separate TF buffer for each namespace, e.g ``/r1/tf``
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As an example, run the following command to launch the diff_drive example within the namespace ``r1``
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.. code-block:: bash
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ros2 launch gazebo_ros2_control_demos diff_drive_namespaced.launch.py
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A second method to launch an instance with a particular namespace is by using the Gazebo ``spawn_entity.py`` tool and setting the ``-robot_namespace`` parameter to the script:
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.. code-block:: bash
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ros2 run gazebo_ros spawn_entity.py -entity robot_1 -robot_namespace r1 -topic robot_description
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The script calls the ``spawn_entity`` service to spawn an entity named ``robot_1`` in the namespace ``r1``. It is assumed that a robot description is being published by a ``robot_state_publisher`` node on the topic ``robot_description``, this will also be used for the ``gazebo_ros2_control`` plugin.
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The ``spawn_entity.py`` script will rewrite the robot description to include a namespace for every plugin tag. Please note that this method will apply a namespace to every plugin in the robot description. It will also overwrite any existing namespaces set in the description file.
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As an example, run the following command to spawn two diff_drive robots in the namespaces ``r1`` and ``r2``
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.. note::
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The ros2_control settings for the controller_manager and the controller defined in ``diff_drive_controller_namespaced.yaml`` use wildcards to match both namespaces.
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.. code-block:: bash
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ros2 launch gazebo_ros2_control_demos diff_drive_pair_namespaced.launch.py
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gazebo_ros2_control_demos
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==========================================
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‎gazebo_ros2_control/src/gazebo_ros2_control_plugin.cpp

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@@ -226,24 +226,10 @@ void GazeboRosControlPlugin::Load(gazebo::physics::ModelPtr parent, sdf::Element
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if (sdf->HasElement("ros")) {
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sdf = sdf->GetElement("ros");
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// Set namespace if tag is present
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if (sdf->HasElement("namespace")) {
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std::string ns = sdf->GetElement("namespace")->Get<std::string>();
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// prevent exception: namespace must be absolute, it must lead with a '/'
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if (ns.empty() || ns[0] != '/') {
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ns = '/' + ns;
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}
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std::string ns_arg = std::string("__ns:=") + ns;
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arguments.push_back(RCL_REMAP_FLAG);
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arguments.push_back(ns_arg);
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}
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// Get list of remapping rules from SDF
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if (sdf->HasElement("remapping")) {
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sdf::ElementPtr argument_sdf = sdf->GetElement("remapping");
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arguments.push_back(RCL_ROS_ARGS_FLAG);
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while (argument_sdf) {
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std::string argument = argument_sdf->Get<std::string>();
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arguments.push_back(RCL_REMAP_FLAG);

‎gazebo_ros2_control_demos/config/diff_drive_controller_namespaced.yaml

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/**/controller_manager:
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ros__parameters:
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update_rate: 100 # Hz
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use_sim_time: true
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joint_state_broadcaster:
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type: joint_state_broadcaster/JointStateBroadcaster
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diff_drive_base_controller:
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type: diff_drive_controller/DiffDriveController
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/**/diff_drive_base_controller:
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ros__parameters:
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left_wheel_names: ["left_wheel_joint"]
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right_wheel_names: ["right_wheel_joint"]
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wheel_separation: 1.25
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wheel_radius: 0.3
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wheel_separation_multiplier: 1.0
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left_wheel_radius_multiplier: 1.0
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right_wheel_radius_multiplier: 1.0
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publish_rate: 50.0
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odom_frame_id: odom
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base_frame_id: chassis
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pose_covariance_diagonal : [0.001, 0.001, 0.0, 0.0, 0.0, 0.01]
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twist_covariance_diagonal: [0.001, 0.0, 0.0, 0.0, 0.0, 0.01]
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open_loop: true
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enable_odom_tf: true
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cmd_vel_timeout: 0.5
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#publish_limited_velocity: true
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#velocity_rolling_window_size: 10
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# Velocity and acceleration limits
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# Whenever a min_* is unspecified, default to -max_*
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linear.x.max_velocity: 1.0
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linear.x.min_velocity: -1.0
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linear.x.max_acceleration: 1.0
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linear.x.max_jerk: 0.0
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linear.x.min_jerk: 0.0
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angular.z.max_velocity: 1.0
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angular.z.min_velocity: -1.0
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angular.z.max_acceleration: 1.0
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angular.z.min_acceleration: -1.0
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angular.z.max_jerk: 0.0
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angular.z.min_jerk: 0.0

‎gazebo_ros2_control_demos/launch/diff_drive_namespaced.launch.py

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# Copyright 2024 Open Source Robotics Foundation, Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import os
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from ament_index_python.packages import get_package_share_directory
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from launch import LaunchDescription
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from launch.actions import ExecuteProcess, IncludeLaunchDescription, RegisterEventHandler
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from launch.event_handlers import OnProcessExit
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from launch.launch_description_sources import PythonLaunchDescriptionSource
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from launch_ros.actions import Node
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import xacro
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def generate_launch_description():
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gazebo = IncludeLaunchDescription(
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PythonLaunchDescriptionSource([os.path.join(
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get_package_share_directory('gazebo_ros'), 'launch'), '/gazebo.launch.py']),
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)
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gazebo_ros2_control_demos_path = os.path.join(
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get_package_share_directory('gazebo_ros2_control_demos'))
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xacro_file = os.path.join(gazebo_ros2_control_demos_path,
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'urdf',
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'test_diff_drive_namespaced.xacro.urdf')
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doc = xacro.parse(open(xacro_file))
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xacro.process_doc(doc)
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params = {'robot_description': doc.toxml()}
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node_robot_state_publisher = Node(
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package='robot_state_publisher',
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executable='robot_state_publisher',
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namespace='r1',
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output='screen',
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parameters=[params]
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)
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spawn_entity = Node(package='gazebo_ros', executable='spawn_entity.py',
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namespace='r1',
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arguments=['-topic', 'robot_description',
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'-entity', 'diffbot'],
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output='screen')
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load_joint_state_broadcaster = ExecuteProcess(
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cmd=['ros2', 'control', 'load_controller', '--set-state', 'active',
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'joint_state_broadcaster',
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'-c', '/r1/controller_manager'],
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output='screen'
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)
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load_diff_drive_base_controller = ExecuteProcess(
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cmd=['ros2', 'control', 'load_controller', '--set-state', 'active',
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'diff_drive_base_controller',
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'-c', '/r1/controller_manager'],
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output='screen'
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)
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return LaunchDescription([
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RegisterEventHandler(
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event_handler=OnProcessExit(
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target_action=spawn_entity,
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on_exit=[load_joint_state_broadcaster],
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)
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),
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RegisterEventHandler(
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event_handler=OnProcessExit(
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target_action=load_joint_state_broadcaster,
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on_exit=[load_diff_drive_base_controller],
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)
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),
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gazebo,
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node_robot_state_publisher,
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spawn_entity,
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])

‎gazebo_ros2_control_demos/launch/diff_drive_pair_namespaced.launch.py

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# Copyright 2024 Open Source Robotics Foundation, Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import os
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from ament_index_python.packages import get_package_share_directory
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from launch import LaunchDescription
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from launch.actions import ExecuteProcess, IncludeLaunchDescription, RegisterEventHandler
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from launch.event_handlers import OnProcessExit
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from launch.launch_description_sources import PythonLaunchDescriptionSource
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from launch_ros.actions import Node
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import xacro
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def generate_launch_description():
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gazebo = IncludeLaunchDescription(
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PythonLaunchDescriptionSource([os.path.join(
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get_package_share_directory('gazebo_ros'), 'launch'), '/gazebo.launch.py']),
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)
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gazebo_ros2_control_demos_path = os.path.join(
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get_package_share_directory('gazebo_ros2_control_demos'))
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xacro_file = os.path.join(gazebo_ros2_control_demos_path,
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'urdf',
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'test_diff_drive_namespaced.xacro.urdf')
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doc = xacro.parse(open(xacro_file))
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xacro.process_doc(doc)
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params = {'robot_description': doc.toxml()}
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node_robot_state_publisher_r1 = Node(
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package='robot_state_publisher',
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executable='robot_state_publisher',
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namespace='r1',
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output='screen',
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parameters=[params]
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)
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node_robot_state_publisher_r2 = Node(
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package='robot_state_publisher',
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executable='robot_state_publisher',
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namespace='r2',
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output='screen',
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parameters=[params]
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)
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spawn_entity_r1 = Node(
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package='gazebo_ros', executable='spawn_entity.py',
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arguments=[
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'-topic', '/r1/robot_description',
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'-robot_namespace', 'r1',
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'-entity', 'diffbot1'
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],
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output='screen'
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)
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spawn_entity_r2 = Node(
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package='gazebo_ros', executable='spawn_entity.py',
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arguments=[
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'-topic', '/r2/robot_description',
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'-robot_namespace', 'r2',
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'-entity', 'diffbot1'
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],
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output='screen'
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)
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load_joint_state_broadcaster_r1 = ExecuteProcess(
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cmd=['ros2', 'control', 'load_controller', '--set-state', 'active',
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'joint_state_broadcaster',
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'-c', '/r1/controller_manager'],
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output='screen'
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)
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load_diff_drive_base_controller_r1 = ExecuteProcess(
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cmd=['ros2', 'control', 'load_controller', '--set-state', 'active',
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'diff_drive_base_controller',
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'-c', '/r1/controller_manager'],
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output='screen'
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)
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load_joint_state_broadcaster_r2 = ExecuteProcess(
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cmd=['ros2', 'control', 'load_controller', '--set-state', 'active',
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'joint_state_broadcaster',
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'-c', '/r2/controller_manager'],
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output='screen'
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)
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load_diff_drive_base_controller_r2 = ExecuteProcess(
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cmd=['ros2', 'control', 'load_controller', '--set-state', 'active',
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'diff_drive_base_controller',
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'-c', '/r2/controller_manager'],
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output='screen'
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)
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return LaunchDescription([
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RegisterEventHandler(
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event_handler=OnProcessExit(
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target_action=spawn_entity_r1,
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on_exit=[
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load_joint_state_broadcaster_r1,
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load_diff_drive_base_controller_r1
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],
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)
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),
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RegisterEventHandler(
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event_handler=OnProcessExit(
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target_action=spawn_entity_r2,
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on_exit=[
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load_joint_state_broadcaster_r2,
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load_diff_drive_base_controller_r2
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],
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)
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),
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gazebo,
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node_robot_state_publisher_r1,
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node_robot_state_publisher_r2,
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spawn_entity_r1,
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spawn_entity_r2,
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])

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