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Merge branch 'rolling' into rm/iron
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ahcorde authored Dec 10, 2024
2 parents d6cae79 + d2b2f0d commit 7f854dc
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2 changes: 1 addition & 1 deletion .pre-commit-config.yaml
Original file line number Diff line number Diff line change
Expand Up @@ -136,7 +136,7 @@ repos:
exclude: CHANGELOG\.rst|\.(svg|pyc)$

- repo: https://github.com/python-jsonschema/check-jsonschema
rev: 0.29.4
rev: 0.30.0
hooks:
- id: check-github-workflows
args: ["--verbose"]
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70 changes: 63 additions & 7 deletions doc/index.rst
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Expand Up @@ -61,13 +61,13 @@ To run the demo
ros2 run gz_ros2_control_demos example_position
Add ros2_control tag to a URDF
Add ros2_control tag to a URDF or SDF
==========================================

Simple setup
-----------------------------------------------------------

To use *ros2_control* with your robot, you need to add some additional elements to your URDF.
To use *ros2_control* with your robot, you need to add some additional elements to your URDF or SDF.
You should include the tag ``<ros2_control>`` to access and control the robot interfaces. We should
include:

Expand Down Expand Up @@ -96,7 +96,7 @@ include:
Using mimic joints in simulation
-----------------------------------------------------------

To use ``mimic`` joints in *gz_ros2_control* you should define its parameters in your URDF, i.e, set the ``<mimic>`` tag to the mimicked joint (see the `URDF specification <https://wiki.ros.org/urdf/XML/joint>`__)
To use ``mimic`` joints in *gz_ros2_control* you should define its parameters in your URDF or SDF, i.e, set the ``<mimic>`` tag to the mimicked joint (see the `URDF specification <https://wiki.ros.org/urdf/XML/joint>`__ or the `SDF specification <http://sdformat.org/spec?ver=1.11&elem=joint#axis_mimic>`__)

.. code-block:: xml
Expand All @@ -122,12 +122,14 @@ The mimic joint must not have command interfaces configured in the ``<ros2_contr
Add the gz_ros2_control plugin
==========================================

In addition to the *ros2_control* tags, a Gazebo plugin needs to be added to your URDF that
In addition to the *ros2_control* tags, a Gazebo plugin needs to be added to your URDF or SDF that
actually parses the *ros2_control* tags and loads the appropriate hardware interfaces and
controller manager. By default the *gz_ros2_control* plugin is very simple, though it is also
extensible via an additional plugin architecture to allow power users to create their own custom
robot hardware interfaces between *ros2_control* and Gazebo.

URDF:

.. code-block:: xml
<gazebo>
Expand All @@ -136,12 +138,20 @@ robot hardware interfaces between *ros2_control* and Gazebo.
</plugin>
</gazebo>
SDF:

.. code-block:: xml
<plugin filename="libgz_ros2_control-system.so" name="gz_ros2_control::GazeboSimROS2ControlPlugin">
<parameters>$(find gz_ros2_control_demos)/config/cart_controller.yaml</parameters>
</plugin>
The *gz_ros2_control* ``<plugin>`` tag also has the following optional child elements:

* ``<parameters>``: A YAML file with the configuration of the controllers. This element can be given multiple times to load multiple files.
* ``<controller_manager_name>``: Set controller manager name (default: ``controller_manager``)

The following additional parameters can be set via child elements in the URDF or via ROS parameters in the YAML file above:
The following additional parameters can be set via child elements in the URDF/SDF or via ROS parameters in the YAML file above:

* ``<hold_joints>``: if set to true (default), it will hold the joints' position if their interface was not claimed, e.g., the controller hasn't been activated yet.
* ``<position_proportional_gain>``: Set the proportional gain. (default: 0.1) This determines the setpoint for a position-controlled joint ``joint_velocity = joint_position_error * position_proportional_gain``.
Expand All @@ -157,6 +167,8 @@ or via ROS parameters:
Additionally, one can specify a namespace and remapping rules, which will be forwarded to the controller_manager and loaded controllers. Add the following ``<ros>`` section:

URDF:

.. code-block:: xml
<gazebo>
Expand All @@ -169,10 +181,23 @@ Additionally, one can specify a namespace and remapping rules, which will be for
</plugin>
</gazebo>
SDF:

.. code-block:: xml
<plugin filename="libgz_ros2_control-system.so" name="gz_ros2_control::GazeboSimROS2ControlPlugin">
...
<ros>
<namespace>my_namespace</namespace>
<remapping>/robot_description:=/robot_description_full</remapping>
</ros>
</plugin>
Default gz_ros2_control Behavior
-----------------------------------------------------------

By default, without a ``<plugin>`` tag, *gz_ros2_control* will attempt to get all of the information it needs to interface with a ros2_control-based controller out of the URDF. This is sufficient for most cases, and good for at least getting started.
By default, without a ``<plugin>`` tag, *gz_ros2_control* will attempt to get all of the information it needs to interface with a ros2_control-based controller out of the URDF or SDF. This is sufficient for most cases, and good for at least getting started.

The default behavior provides the following ros2_control interfaces:

Expand All @@ -188,9 +213,11 @@ The *gz_ros2_control* Gazebo plugin also provides a pluginlib-based interface to
These plugins must inherit the ``gz_ros2_control::GazeboSimSystemInterface``, which implements a simulated *ros2_control*
``hardware_interface::SystemInterface``. SystemInterface provides API-level access to read and command joint properties.

The respective GazeboSimSystemInterface sub-class is specified in a URDF model and is loaded when the
The respective GazeboSimSystemInterface sub-class is specified in a URDF or SDF model and is loaded when the
robot model is loaded. For example, the following XML will load the default plugin:

URDF:

.. code-block:: xml
<ros2_control name="GazeboSimSystem" type="system">
Expand All @@ -205,12 +232,28 @@ robot model is loaded. For example, the following XML will load the default plug
</plugin>
</gazebo>
SDF:

.. code-block:: xml
<ros2_control name="GazeboSimSystem" type="system">
<hardware>
<plugin>gz_ros2_control/GazeboSimSystem</plugin>
</hardware>
...
<ros2_control>
<plugin name="gz_ros2_control::GazeboSimROS2ControlPlugin" filename="libgz_ros2_control-system">
...
</plugin>
Set up controllers
-----------------------------------------------------------

Use the tag ``<parameters>`` inside ``<plugin>`` to set the YAML file with the controller configuration
and use the tag ``<controller_manager_prefix_node_name>`` to set the controller manager node name.

URDF:

.. code-block:: xml
<gazebo>
Expand All @@ -220,6 +263,15 @@ and use the tag ``<controller_manager_prefix_node_name>`` to set the controller
</plugin>
<gazebo>
SDF:

.. code-block:: xml
<plugin name="gz_ros2_control::GazeboSimROS2ControlPlugin" filename="libgz_ros2_control-system">
<parameters>$(find gz_ros2_control_demos)/config/cart_controller.yaml</parameters>
<controller_manager_prefix_node_name>controller_manager</controller_manager_prefix_node_name>
</plugin>
The following is a basic configuration of the controllers:

- ``joint_state_broadcaster``: This controller publishes the state of all resources registered to a ``hardware_interface::StateInterface`` to a topic of type ``sensor_msgs/msg/JointState``.
Expand All @@ -233,6 +285,10 @@ gz_ros2_control_demos
==========================================

There are some examples in the *gz_ros2_control_demos* package.
To specify whether to use URDF or SDF, you can launch the demo in the following way (the default is URDF):
.. code-block:: shell
ros2 launch gz_ros2_control_demos <launch file> description_format:=sdf
Cart on rail
-----------------------------------------------------------
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1 change: 1 addition & 0 deletions gz_ros2_control_demos/CMakeLists.txt
Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,7 @@ find_package(geometry_msgs REQUIRED)
install(DIRECTORY
launch
config
sdf
urdf
DESTINATION share/${PROJECT_NAME}/
)
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53 changes: 31 additions & 22 deletions gz_ros2_control_demos/launch/ackermann_drive_example.launch.py
Original file line number Diff line number Diff line change
Expand Up @@ -13,7 +13,7 @@
# limitations under the License.

from launch import LaunchDescription
from launch.actions import DeclareLaunchArgument, IncludeLaunchDescription
from launch.actions import DeclareLaunchArgument, IncludeLaunchDescription, OpaqueFunction
from launch.actions import RegisterEventHandler
from launch.event_handlers import OnProcessExit
from launch.launch_description_sources import PythonLaunchDescriptionSource
Expand All @@ -27,18 +27,29 @@ 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('gz_ros2_control_demos'),
'urdf', 'test_ackermann_drive.xacro.urdf']
),
]
)
robot_description = {'robot_description': robot_description_content}
def robot_state_publisher(context):
performed_description_format = LaunchConfiguration('description_format').perform(context)
# Get URDF or SDF via xacro
robot_description_content = Command(
[
PathJoinSubstitution([FindExecutable(name='xacro')]),
' ',
PathJoinSubstitution([
FindPackageShare('gz_ros2_control_demos'),
performed_description_format,
f'test_ackermann_drive.xacro.{performed_description_format}'
]),
]
)
robot_description = {'robot_description': robot_description_content}
node_robot_state_publisher = Node(
package='robot_state_publisher',
executable='robot_state_publisher',
output='screen',
parameters=[robot_description]
)
return [node_robot_state_publisher]

robot_controllers = PathJoinSubstitution(
[
FindPackageShare('gz_ros2_control_demos'),
Expand All @@ -47,13 +58,6 @@ def generate_launch_description():
]
)

node_robot_state_publisher = Node(
package='robot_state_publisher',
executable='robot_state_publisher',
output='screen',
parameters=[robot_description]
)

gz_spawn_entity = Node(
package='ros_gz_sim',
executable='create',
Expand Down Expand Up @@ -84,7 +88,7 @@ def generate_launch_description():
output='screen'
)

return LaunchDescription([
ld = LaunchDescription([
bridge,
# Launch gazebo environment
IncludeLaunchDescription(
Expand All @@ -105,11 +109,16 @@ def generate_launch_description():
on_exit=[ackermann_steering_controller_spawner],
)
),
node_robot_state_publisher,
gz_spawn_entity,
# Launch Arguments
DeclareLaunchArgument(
'use_sim_time',
default_value=use_sim_time,
description='If true, use simulated clock'),
DeclareLaunchArgument(
'description_format',
default_value='urdf',
description='Robot description format to use, urdf or sdf'),
])
ld.add_action(OpaqueFunction(function=robot_state_publisher))
return ld
9 changes: 9 additions & 0 deletions gz_ros2_control_demos/launch/cart_example_effort.launch.py
Original file line number Diff line number Diff line change
Expand Up @@ -77,6 +77,14 @@ def generate_launch_description():
],
)

# Bridge
bridge = Node(
package='ros_gz_bridge',
executable='parameter_bridge',
arguments=['/clock@rosgraph_msgs/msg/Clock[gz.msgs.Clock'],
output='screen'
)

return LaunchDescription([
# Launch gazebo environment
IncludeLaunchDescription(
Expand All @@ -97,6 +105,7 @@ def generate_launch_description():
on_exit=[effort_controller_spawner],
)
),
bridge,
node_robot_state_publisher,
gz_spawn_entity,
# Launch Arguments
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12 changes: 11 additions & 1 deletion gz_ros2_control_demos/launch/cart_example_position.launch.py
Original file line number Diff line number Diff line change
Expand Up @@ -65,7 +65,8 @@ def generate_launch_description():
joint_state_broadcaster_spawner = Node(
package='controller_manager',
executable='spawner',
arguments=['joint_state_broadcaster'],
arguments=['joint_state_broadcaster',
],
)
joint_trajectory_controller_spawner = Node(
package='controller_manager',
Expand All @@ -77,6 +78,14 @@ def generate_launch_description():
],
)

# Bridge
bridge = Node(
package='ros_gz_bridge',
executable='parameter_bridge',
arguments=['/clock@rosgraph_msgs/msg/Clock[gz.msgs.Clock'],
output='screen'
)

return LaunchDescription([
# Launch gazebo environment
IncludeLaunchDescription(
Expand All @@ -97,6 +106,7 @@ def generate_launch_description():
on_exit=[joint_trajectory_controller_spawner],
)
),
bridge,
node_robot_state_publisher,
gz_spawn_entity,
# Launch Arguments
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9 changes: 9 additions & 0 deletions gz_ros2_control_demos/launch/cart_example_velocity.launch.py
Original file line number Diff line number Diff line change
Expand Up @@ -86,6 +86,14 @@ def generate_launch_description():
],
)

# Bridge
bridge = Node(
package='ros_gz_bridge',
executable='parameter_bridge',
arguments=['/clock@rosgraph_msgs/msg/Clock[gz.msgs.Clock'],
output='screen'
)

return LaunchDescription([
# Launch gazebo environment
IncludeLaunchDescription(
Expand All @@ -107,6 +115,7 @@ def generate_launch_description():
imu_sensor_broadcaster_spawner],
)
),
bridge,
node_robot_state_publisher,
gz_spawn_entity,
# Launch Arguments
Expand Down
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