Update docs and cleanup member of GazeboSimROS2ControlPluginPrivate (…

…#363)

doc/index.rst

@@ -131,17 +131,30 @@ robot hardware interfaces between *ros2_control* and Gazebo.
 .. code-block:: xml
 
   <gazebo>
-      <plugin filename="libgz_ros2_control-system.so" name="gz_ros2_control::GazeboSimROS2ControlPlugin">
-        <robot_param>robot_description</robot_param>
-        <robot_param_node>robot_state_publisher</robot_param_node>
-        <parameters>$(find gz_ros2_control_demos)/config/cart_controller.yaml</parameters>
-      </plugin>
+    <plugin filename="libgz_ros2_control-system.so" name="gz_ros2_control::GazeboSimROS2ControlPlugin">
+      <parameters>$(find gz_ros2_control_demos)/config/cart_controller.yaml</parameters>
+    </plugin>
   </gazebo>
 
 The *gz_ros2_control* ``<plugin>`` tag also has the following optional child elements:
 
-* ``<parameters>``: YAML file with the configuration of the controllers
+* ``<parameters>``: A YAML file with the configuration of the controllers. This element can be given multiple times to load multiple files.
 * ``<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.
+* ``<controller_manager_name>``: Set controller manager name (default: ``controller_manager``)
+
+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:
+
+.. code-block:: xml
+
+  <gazebo>
+    <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>
+  </gazebo>
 
 Default gz_ros2_control Behavior
 -----------------------------------------------------------

gz_ros2_control/src/gz_ros2_control_plugin.cpp

@@ -159,11 +159,6 @@ class GazeboSimROS2ControlPluginPrivate
   /// \brief Timing
   rclcpp::Duration control_period_ = rclcpp::Duration(1, 0);
 
-  /// \brief Interface loader
-  std::shared_ptr<pluginlib::ClassLoader<
-      gz_ros2_control::GazeboSimSystemInterface>>
-  robot_hw_sim_loader_{nullptr};
-
   /// \brief Controller manager
   std::shared_ptr<controller_manager::ControllerManager>
   controller_manager_{nullptr};