Add controller_stopper documentation

Author: urfeex

ur_robot_driver/doc/controller_stopper.rst

@@ -0,0 +1,29 @@
+.. _controller_stopper:
+
+Controller stopper
+==================
+
+As explained in the section :ref:`robot_startup_program`, the robot needs to run a program in order
+to receive motion commands from the ROS driver. When the program is not running, commands sent to
+the robot will have no effect.
+
+To make that transparent, the ``controller_stopper`` node mirrors that state in the ROS
+controller's state. It listens to the ``/io_and_status_controller/robot_program_running`` topic and
+deactivates all motion controllers  (or any controller not explicitly marked as "consistent", see
+below)when the program is not running.
+
+Once the program is running again, any previously active motion controller will be activated again.
+
+This way, when sending commands to an inactive controller the caller should be transparently
+informed, that the controller cannot accept commands at the moment.
+
+In the same way, any running action on the ROS controller will be aborted, as the controller gets
+deactivated by the controller_stopper.
+
+Parameters
+----------
+
+- ``~consistent_controllers`` (list of strings, default: ``[]``)
+
+  A list of controller names that should not be stopped when the program is not running. Any
+  controller that doesn't require the robot program to be running should be in that list.

ur_robot_driver/doc/index.rst

@@ -18,3 +18,4 @@ ur_robot_driver
    hardware_interface_parameters
    dashboard_client
    robot_state_helper
+   controller_stopper

ur_robot_driver/doc/usage/startup.rst

@@ -71,12 +71,12 @@ Depending on the :ref:`robot control mode<operation_modes>` do the following:
 * When the driver is started with ``headless_mode:=true`` nothing is needed. The driver is running
   already.
 
-.. _continuation_after_interruptions:
+
+.. _verify_calibration:
 
 Verify calibration info is being used correctly
 -----------------------------------------------
 
-.. _verify_calibration:
 
 If you passed a path to an extracted calibration via the *kinematics_params_file*
 parameter, ensure that the loaded calibration matches that of the robot by inspecting the console
@@ -98,9 +98,12 @@ Alternatively, search for the term *checksum* in the console output after launch
 Verify that the printed checksum matches that on the final line of your extracted calibration file.
 
 
+.. _continuation_after_interruptions:
+
 Continuation after interruptions
 --------------------------------
 
+
 Whenever the *External Control URCap* program gets interrupted, it has to be unpaused / restarted.
 
 If that happens, you will see the output ``Connection to reverse interface dropped.``