Dev: Add ROS 2 ethernet support information

Signed-off-by: Ryan Friedman <[email protected]>

dev/source/docs/ros.rst

@@ -36,6 +36,7 @@ These pages will show you how to:
         ROS 2 with SITL <ros2-sitl>
         ROS with SITL in Gazebo <ros-gazebo>
         ROS 2 with SITL in Gazebo <ros2-gazebo>
+        ROS 2 over Ethernet <ros2-over-ethernet>
         Cartographer SLAM with ROS 2 in SITL <ros2-cartographer-slam>
         ROS with distance sensors <ros-distance-sensors>
         ROS with Aruco Boards detection <ros-aruco-detection>

dev/source/docs/ros2-over-ethernet.rst

@@ -0,0 +1,97 @@
+.. _ros2-over-ethernet:
+
+===================
+ROS 2 over Ethernet
+===================
+
+The following tutorial explains how to connect a flight controller to a companion computer using ethernet for DDS communication.
+
+Ensure you have ROS 2 :ref:`installed <ros2>` and have run :ref:`SITL <ros2-sitl>` successfully before attempting this page.
+
+Additionally, make sure you understand the :ref:`basics of networking in ArduPilot. <common-network>`
+
+==========
+Motivation
+==========
+
+Starting in ArduPilot 4.5, ethernet is now supported as a new communication interface.
+Compared to connecting an autopilot over serial, ethernet has the following advantages:
+
+* Ethernet is more immune to noise because it uses twisted pair wiring
+* Ethernet can run multiple protocols over the same protocol (unless you use PPP)
+* Ethernet is easier to debug with tools such as ``tcpdump`` or ``Wireshark``
+* Ethernet uses standard cabling, so it's more difficult to mix up TX and RX
+
+==================
+Physical Equipment
+==================
+
+The following equipment is required to complete this tutorial:
+
+* A computer that can run the MicroROS Agent and the ROS 2 CLI
+* An autopilot with ethernet support
+
+=============================================
+Necessary parameters for static configuration
+=============================================
+
+This list of parameters is given as an example.
+If you had the following static IP addresses:
+
+* An autopilot has the IP address ``192.168.1.6``
+* A Computer running the MicroROS agent has the IP address ``192.168.1.5``
+* The MicroROS agent is running on port ``2019``
+
+Then, you would configure all of the below parameters.
+
+
+.. list-table::
+   :widths: 50 50
+   :header-rows: 1
+
+   * - Parameter Name
+     - Value
+   * - :ref:`DDS_ENABLE<DDS_ENABLE>`
+     - 1
+   * - :ref:`DDS_IP0<DDS_IP0>`
+     - 192
+   * - :ref:`DDS_IP1<DDS_IP1>`
+     - 168
+   * - :ref:`DDS_IP2<DDS_IP2>`
+     - 1
+   * - :ref:`DDS_IP3<DDS_IP3>`
+     - 6
+   * - :ref:`DDS_UDP_PORT<DDS_UDP_PORT>`
+     - 2019
+   * - :ref:`NET_DHCP<NET_DHCP>`
+     - 0
+   * - :ref:`NET_ENABLED<NET_ENABLED>`
+     - 1
+   * - :ref:`NET_IPADDR0<NET_IPADDR0>`
+     - 192
+   * - :ref:`NET_IPADDR1<NET_IPADDR1>`
+     - 168
+   * - :ref:`NET_IPADDR2<NET_IPADDR2>`
+     - 1
+   * - :ref:`NET_IPADDR3<NET_IPADDR3>`
+     - 5
+
+
+Modify the addresses to suit your needs; the rest can remain the same.
+
+=====
+Steps
+=====
+
+#. Flash the autopilot with software compiled with ``--enable-dds``
+#. Connect the autopilot via ethernet to the computer
+#. Open a MavProxy session
+#. Configure the parameters described above, starting with the ``ENABLE`` parameters first. 
+#. Reboot the flight controller
+#. Start the MicroROS Agent with the same port as the parameter for ``DDS_UDP_PORT``
+
+    .. code-block:: bash
+
+        ros2 run micro_ros_agent micro_ros_agent udp4 -p 2019 -r dds_xrce_profile.xml
+
+#. Use the ROS 2 CLI to interact with the autopilot