Add GenericSystem to GPIO example

example_10/bringup/launch/rrbot.launch.py

@@ -14,15 +14,27 @@
 
 
 from launch import LaunchDescription
-from launch.actions import RegisterEventHandler
+from launch.actions import DeclareLaunchArgument, RegisterEventHandler
 from launch.event_handlers import OnProcessExit
-from launch.substitutions import Command, FindExecutable, PathJoinSubstitution
+from launch.substitutions import Command, FindExecutable, PathJoinSubstitution, LaunchConfiguration
 
 from launch_ros.actions import Node
 from launch_ros.substitutions import FindPackageShare
 
 
 def generate_launch_description():
+ # Declare arguments
+ declared_arguments = []
+ declared_arguments.append(
+ DeclareLaunchArgument(
+ "use_mock_hardware",
+ default_value="false",
+ description="Start robot with mock hardware mirroring command to its states.",
+ )
+ )
+ # Initialize Arguments
+ use_mock_hardware = LaunchConfiguration("use_mock_hardware")
+
  # Get URDF via xacro
  robot_description_content = Command(
  [
@@ -35,6 +47,9 @@ def generate_launch_description():
  "rrbot.urdf.xacro",
  ]
  ),
+ " ",
+ "use_mock_hardware:=",
+ use_mock_hardware,
  ]
  )
  robot_description = {"robot_description": robot_description_content}
@@ -94,4 +109,4 @@ def generate_launch_description():
  delay_robot_controller_spawner_after_joint_state_broadcaster_spawner,
  ]
 
- return LaunchDescription(nodes)
+ return LaunchDescription(declared_arguments + nodes)

example_10/description/ros2_control/rrbot.ros2_control.xacro

@@ -1,15 +1,23 @@
 <?xml version="1.0"?>
 <robot xmlns:xacro="http://www.ros.org/wiki/xacro">
 
- <xacro:macro name="rrbot_ros2_control" params="name prefix">
+ <xacro:macro name="rrbot_ros2_control" params="name prefix use_mock_hardware">
 
  <ros2_control name="${name}" type="system">
- <hardware>
- <plugin>ros2_control_demo_example_10/RRBotSystemWithGPIOHardware</plugin>
- <param name="example_param_hw_start_duration_sec">0</param>
- <param name="example_param_hw_stop_duration_sec">3.0</param>
- <param name="example_param_hw_slowdown">100</param>
- </hardware>
+ <xacro:unless value="${use_mock_hardware}">
+ <hardware>
+ <plugin>ros2_control_demo_example_10/RRBotSystemWithGPIOHardware</plugin>
+ <param name="example_param_hw_start_duration_sec">0</param>
+ <param name="example_param_hw_stop_duration_sec">3.0</param>
+ <param name="example_param_hw_slowdown">100</param>
+ </hardware>
+ </xacro:unless>
+ <xacro:if value="${use_mock_hardware}">
+ <hardware>
+ <plugin>mock_components/GenericSystem</plugin>
+ <param name="calculate_dynamics">true</param>
+ </hardware>
+ </xacro:if>
 
  <joint name="${prefix}joint1">
  <command_interface name="position">
@@ -34,7 +42,9 @@
  </gpio>
  <gpio name="flange_vacuum">
  <command_interface name="vacuum"/>
- <state_interface name="vacuum"/> <!-- Needed to know current state of the input -->
+ <state_interface name="vacuum">
+ <param name="initial_value">1.0</param>
+ </state_interface>
  </gpio>
  </ros2_control>
 

example_10/description/urdf/rrbot.urdf.xacro

@@ -6,6 +6,7 @@ https://github.com/ros-simulation/gazebo_ros_demos/blob/kinetic-devel/rrbot_desc
 -->
 <robot xmlns:xacro="http://www.ros.org/wiki/xacro" name="2dof_robot">
  <xacro:arg name="prefix" default="" />
+ <xacro:arg name="use_mock_hardware" default="false" />
 
  <!-- Import RRBot macro -->
  <xacro:include filename="$(find ros2_control_demo_description)/rrbot/urdf/rrbot_description.urdf.xacro" />
@@ -24,6 +25,6 @@ https://github.com/ros-simulation/gazebo_ros_demos/blob/kinetic-devel/rrbot_desc
  </xacro:rrbot>
 
  <xacro:rrbot_ros2_control
- name="RRBot" prefix="$(arg prefix)" />
+ name="RRBot" prefix="$(arg prefix)" use_mock_hardware="$(arg use_mock_hardware)"/>
 
 </robot>

example_10/doc/userdoc.rst

@@ -91,6 +91,103 @@ The *RRBot* URDF files can be found in the ``description/urdf`` folder.
  [RRBotSystemWithGPIOHardware]: Got command 0.5 for GP output 0!
  [RRBotSystemWithGPIOHardware]: Got command 0.7 for GP output 1!
 
+7. Let's introspect the ros2_control hardware component. Calling
+
+ .. code-block:: shell
+
+ ros2 control list_hardware_components
+
+ should give you
+
+ .. code-block:: shell
+
+ Hardware Component 1
+ name: RRBot
+ type: system
+ plugin name: ros2_control_demo_example_10/RRBotSystemWithGPIOHardware
+ state: id=3 label=active
+ command interfaces
+ joint1/position [available] [claimed]
+ joint2/position [available] [claimed]
+ flange_analog_IOs/analog_output1 [available] [claimed]
+ flange_vacuum/vacuum [available] [claimed]
+
+ This shows that the custom hardware interface plugin is loaded and running. If you work on a real
+ robot and don't have a simulator running, it is often faster to use the ``mock_components/GenericSystem``
+ hardware component instead of writing a custom one. Stop the launch file and start it again with
+ an additional parameter
+
+ .. code-block:: shell
+
+ ros2 launch ros2_control_demo_example_10 rrbot.launch.py use_mock_hardware:=True
+
+ Calling ``list_hardware_components`` with the ``-v`` option
+
+ .. code-block:: shell
+
+ ros2 control list_hardware_components -v
+
+ now should give you
+
+ .. code-block:: shell
+
+ Hardware Component 1
+ name: RRBot
+ type: system
+ plugin name: mock_components/GenericSystem
+ state: id=3 label=active
+ command interfaces
+ joint1/position [available] [claimed]
+ joint2/position [available] [claimed]
+ flange_analog_IOs/analog_output1 [available] [claimed]
+ flange_vacuum/vacuum [available] [claimed]
+ state interfaces
+ joint1/position [available]
+ joint2/position [available]
+ flange_analog_IOs/analog_output1 [available]
+ flange_analog_IOs/analog_input1 [available]
+ flange_analog_IOs/analog_input2 [available]
+ flange_vacuum/vacuum [available]
+
+ One can see that the plugin ``mock_components/GenericSystem`` was now loaded instead: It will mirror the command interfaces to state interfaces with identical name. Call
+
+ .. code-block:: shell
+
+ ros2 topic echo /gpio_controller/inputs
+
+ again and you should see that - unless commands are received - the values of the state interfaces are now ``nan`` except for the vacuum interface.
+
+ .. code-block:: shell
+
+ interface_names:
+ - flange_analog_IOs/analog_output1
+ - flange_analog_IOs/analog_input1
+ - flange_analog_IOs/analog_input2
+ - flange_vacuum/vacuum
+ values:
+ - .nan
+ - .nan
+ - .nan
+ - 1.0
+
+ This is, because for the vacuum interface an initial value of ``1.0`` is set in the URDF file.
+
+ .. code-block:: xml
+
+ <gpio name="flange_vacuum">
+ <command_interface name="vacuum"/>
+ <state_interface name="vacuum">
+ <param name="initial_value">1.0</param>
+ </state_interface>
+ </gpio>
+
+ Call again
+
+ .. code-block:: shell
+
+ ros2 topic pub /gpio_controller/commands std_msgs/msg/Float64MultiArray "{data: [0.5,0.7]}"
+
+ and you will see that the GPIO command interfaces will be mirrored to their respective state interfaces.
 
 Files used for this demos
 -------------------------
@@ -104,7 +201,11 @@ Files used for this demos
 
 - RViz configuration: `rrbot.rviz <https://github.com/ros-controls/ros2_control_demos/tree/{REPOS_FILE_BRANCH}/ros2_control_demo_description/rrbot/rviz/rrbot.rviz>`__
 
-- Hardware interface plugin: `rrbot.cpp <https://github.com/ros-controls/ros2_control_demos/tree/{REPOS_FILE_BRANCH}/example_10/hardware/rrbot.cpp>`__
+- Hardware interface plugin:
+
+ + `rrbot.cpp <https://github.com/ros-controls/ros2_control_demos/tree/{REPOS_FILE_BRANCH}/example_10/hardware/rrbot.cpp>`__
+ + `generic_system.cpp <https://github.com/ros-controls/ros2_control/tree/{REPOS_FILE_BRANCH}/hardware_interface/src/mock_components/generic_system.cpp>`__
+
 - GPIO controller: `gpio_controller.cpp <https://github.com/ros-controls/ros2_control_demos/tree/{REPOS_FILE_BRANCH}/example_10/controllers/gpio_controller.cpp>`__