Docs for Loopback Simulator C++ migration (#897)

* Docs for Loopback Simulator C++ migration

Signed-off-by: Tony Najjar <tony.najjar@dexory.com>

* Update odom_publish_dur parameter description for clarity and improve performance note for Loopback Simulator migration to C++

Signed-off-by: Tony Najjar <tony.najjar@dexory.com>

* Update migration/Kilted.rst

Co-authored-by: Steve Macenski <stevenmacenski@gmail.com>
Signed-off-by: Tony Najjar <tony.najjar.1997@gmail.com>

---------

Signed-off-by: Tony Najjar <tony.najjar@dexory.com>
Signed-off-by: Tony Najjar <tony.najjar.1997@gmail.com>
Co-authored-by: Steve Macenski <stevenmacenski@gmail.com>

Author: tonynajjar

configuration/packages/configuring-loopback-sim.rst

@@ -86,34 +86,68 @@ Parameters
   ============== ==============
   Type           Default
   -------------- --------------
-  string         0.1
+  double         0.1
   ============== ==============
 
   Description
     The duration between publishing scan (in sec)
 
+:odom_publish_dur:
+
+  ============== =================
+  Type           Default
+  -------------- -----------------
+  double         <update_duration>
+  ============== =================
+
+  Description
+    The duration between publishing odometry (in sec). Defaults to ``update_duration``.
+
 :publish_map_odom_tf:
 
   ============== ==============
   Type           Default
   -------------- --------------
-  string         true
+  bool           true
   ============== ==============
 
   Description
     Whether or not to publish tf from ``map_frame_id`` to ``odom_frame_id``
 
+:publish_scan:
+
+  ============== ==============
+  Type           Default
+  -------------- --------------
+  bool           true
+  ============== ==============
+
+  Description
+    Whether or not to publish a fake laser scan.
+
 :publish_clock:
 
   ============== ==============
   Type           Default
   -------------- --------------
-  string         true
+  bool           true
   ============== ==============
 
   Description
     Whether or not to publish simulated clock to ``/clock``
 
+:speed_factor:
+
+  ============== ==============
+  Type           Default
+  -------------- --------------
+  double         1.0
+  ============== ==============
+
+  Description
+    Speed factor for the simulated clock, e.g. ``2.0`` runs simulation at 2x wall time.
+    Only used when ``publish_clock`` is ``true``. Dynamically reconfigurable.
+
 :scan_range_min:
 
   ============== ==============
@@ -181,6 +215,17 @@ Parameters
     Whether to use ``inf`` for out-of-range values.
     If ``false``, values are set to ``scan_range_max - 0.1`` instead.
 
+:scan_noise_std:
+
+  ============== ==============
+  Type           Default
+  -------------- --------------
+  double         0.01
+  ============== ==============
+
+  Description
+    Standard deviation of Gaussian noise added to scan ranges (in meters).
+
 Example
 *******
 .. code-block:: yaml
@@ -192,9 +237,13 @@ Example
         map_frame_id: "map"
         scan_frame_id: "base_scan"  # tb4_loopback_simulator.launch.py remaps to 'rplidar_link'
         update_duration: 0.02
+        publish_scan: true
+        publish_clock: true
+        speed_factor: 1.0
         scan_range_min: 0.05
         scan_range_max: 30.0
         scan_angle_min: -3.1415
         scan_angle_max: 3.1415
         scan_angle_increment: 0.02617
         scan_use_inf: true
+        scan_noise_std: 0.01

migration/Kilted.rst

@@ -925,3 +925,16 @@ ValidatePath / IsPathValid parameter changes
 `PR #6027 <https://github.com/ros-navigation/navigation2/pull/6027>`_ renames the ``check_full_path`` parameter to ``stop_at_first_collision`` in both the ``ValidatePath`` BT node and the ``IsPathValid`` service definition. The boolean semantics are inverted: ``check_full_path=false`` (old default) is equivalent to ``stop_at_first_collision=true`` (new default).
 
 Additionally, a new ``max_lookahead_distance`` parameter (default ``-1.0``) has been added to both the BT node and the service. When set to a positive value, only the portion of the path within that distance ahead of the robot is validated, improving efficiency when full path validation is not necessary.
+
+Nav2 Loopback Simulator converted to C++
+----------------------------------------
+
+`PR #6062 <https://github.com/ros-navigation/navigation2/pull/6062>`_ converts ``nav2_loopback_sim`` from Python to C++ for improved performance and consistency with the rest of the Nav2 stack. This results in roughly a 2x improvement in CPU consumption.
+
+Key changes:
+
+- The ``clock_publisher`` is no longer a separate node. It is now embedded within the ``loopback_simulator`` node. Launch files that previously launched both nodes should be updated to launch only the ``loopback_simulator`` node.
+- A new ``speed_factor`` parameter (default ``1.0``) controls the simulated clock speed (e.g. ``2.0`` for 2x). This parameter is dynamically reconfigurable.
+- New parameters ``publish_scan``, ``odom_publish_dur``, and ``scan_noise_std`` are available.
+
+See :ref:`configuring_loopback_sim` for full parameter documentation.