[moveit] Disable execution_duration_monitoring by default (#1133)

* [moveit] Disable execution_duration_monitoring by default

* Add note about disabling TEM in docs

* Update documentation

ur_moveit_config/launch/ur_moveit.launch.py

@@ -188,6 +188,8 @@ def launch_setup(context, *args, **kwargs):
         "trajectory_execution.allowed_execution_duration_scaling": 1.2,
         "trajectory_execution.allowed_goal_duration_margin": 0.5,
         "trajectory_execution.allowed_start_tolerance": 0.01,
+        # Execution time monitoring can be incompatible with the scaled JTC
+        "trajectory_execution.execution_duration_monitoring": False,
     }
 
     planning_scene_monitor_parameters = {

ur_robot_driver/doc/usage.rst

@@ -191,6 +191,26 @@ To test the driver with the example MoveIt-setup, first start the driver as desc
 Now you should be able to use the MoveIt Plugin in rviz2 to plan and execute trajectories with the
 robot as explained `here <https://moveit.picknik.ai/main/doc/tutorials/quickstart_in_rviz/quickstart_in_rviz_tutorial.html>`_.
 
+.. note::
+   The MoveIt configuration provided here has Trajectory Execution Monitoring (TEM) *disabled*, as the
+   Scaled Joint Trajectory Controller may cause trajectories to be executed at a lower velocity
+   than they were originally planned by MoveIt. MoveIt's TEM however is not aware of this
+   deliberate slow-down due to scaling and will in most cases unnecessarily (and unexpectedly)
+   abort goals.
+
+   Until this incompatibility is resolved, the default value for ``execution_duration_monitoring``
+   is set to ``false``. Users who wish to temporarily (re)enable TEM at runtime (for use with
+   other, non-scaling controllers) can do so using the ROS 2 parameter services supported by
+   MoveIt.
+
+   .. literalinclude:: ../../ur_moveit_config/launch/ur_moveit.launch.py
+      :language: python
+      :start-at: trajectory_execution =
+      :end-at: execution_duration_monitoring": False
+      :append: }
+      :dedent: 4
+      :caption: ur_moveit_config/launch/ur_moveit.launch.py
+
 Fake hardware on ROS2 Galactic
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^