adding uml class diagram of example_1

example_1/doc/summary_explanation_example_1.md

@@ -0,0 +1,78 @@
+# ROS2 Control - Example 1 (RRBot System Position Only)
+
+This example demonstrates the **basic architecture of ROS2 Control** using a simple 2-joint robot (**RRBot**) with a custom hardware interface and controllers.
+
+---
+
+## Hardware
+
+The robot (**RRBot**) is a simple 2-joint robot.
+
+A custom hardware interface **`RRBotSystemPositionOnlyHardware`** is implemented in:  
+`ros2_control_demo_example_1/rrbot_hardware_interface.cpp`
+
+This hardware plugin:
+
+- Inherits from **`hardware_interface::SystemInterface`**
+- Defines how to **read joint positions** (from hardware, simulated here)
+- Defines how to **write commands** (set joint positions)
+- Is registered in a **`plugin.xml`** file so the **ResourceManager** can load it
+
+From the UML:  
+- `hardware_interface::SystemInterface` → implemented by the RRBot hardware plugin  
+- `hardware_interface::ResourceManager` → manages your hardware plugin after loading it  
+
+---
+
+## Robot Description (URDF/Xacro)
+
+The robot description is defined in:  
+`rrbot.urdf.xacro`
+
+The URDF contains:
+
+- Links and joints of the robot  
+- A `<ros2_control>` tag specifying which hardware plugin to load  
+
+When launched, **ros2_control** reads this URDF and knows:
+
+- Which joints exist  
+- Which hardware plugin provides those joints  
+
+From the UML:  
+- `robot_config (URDF)` → parsed into **`hardware_interface::HardwareInfo`** and passed to **ResourceManager**  
+
+---
+
+## Controller Manager
+
+The **`controller_manager::ControllerManager`** is the core ROS2 node.  
+
+Responsibilities:
+
+- Loads your hardware plugin (via **ResourceManager**)  
+- Loads and manages controllers (defined in a YAML config file)  
+
+From the UML:  
+- `controller_manager::ControllerManager` → central node  
+- Uses `controllers_config (YAML)` and `robot_config (URDF)` to configure everything  
+
+---
+
+## Controllers
+
+**Forward Command Controller**  
+- `forward_position_controller` (from `forward_command_controller` package)  
+- Directly forwards position commands to the hardware interface  
+
+**Joint State Broadcaster**  
+- Publishes **`/joint_states`**  
+- Allows visualization of the robot in RViz  
+
+From the UML:  
+- `controller_interface::ControllerInterface` → base class for controllers  
+- `forward_command_controller::ForwardCommandController` → used in this demo  
+- `joint_state_broadcaster::JointStateBroadcaster` → publishes joint states  
+
+---
+

example_1/doc/userdoc.rst

@@ -501,3 +501,14 @@ Controllers from this demo
   * ``Joint State Broadcaster`` (`ros2_controllers repository <https://github.com/ros-controls/ros2_controllers/tree/{REPOS_FILE_BRANCH}/joint_state_broadcaster>`__): :ref:`doc <joint_state_broadcaster_userdoc>`
   * ``Forward Command Controller`` (`ros2_controllers repository <https://github.com/ros-controls/ros2_controllers/tree/{REPOS_FILE_BRANCH}/forward_command_controller>`__): :ref:`doc <forward_command_controller_userdoc>`
   * ``Joint Trajectory Controller`` (`ros2_controllers repository <https://github.com/ros-controls/ros2_controllers/tree/{REPOS_FILE_BRANCH}/joint_trajectory_controller>`__): :ref:`doc <joint_trajectory_controller_userdoc>`
+
+
+
+Additional Resources for this demo
+----------------------------------
+* `UML Class Diagram of example_1 <https://github.com/ros-controls/ros2_control_demos/tree/{REPOS_FILE_BRANCH}/example_1/doc/ros2_control_demo_example_1.svg>`__  a visual representation of the RRBot hardware interface architecture.
+
+* `Summary Explanation of example_1 <https://github.com/ros-controls/ros2_control_demos/tree/{REPOS_FILE_BRANCH}/example_1/doc/summary_explanation_example_1.md>`__  a step-by-step explanation of the demo’s architecture and component interaction.
+
+
+