Merge pull request #306 from PickNikRobotics/davetcoleman-patch-2

Improve inline documentation for constrained_pick_place

src/picknik_ur_mock_hw_config/objectives/constrained_pick_place.xml

@@ -1,21 +1,24 @@
 <?xml version='1.0' encoding='UTF-8'?>
 <root BTCPP_format="4" main_tree_to_execute="Constrained Pick and Place">
   <!-- ////////// -->
-  <BehaviorTree ID="Constrained Pick and Place" _description="Pick and place an object with constraints on the gripper's range of motion" _favorite="true">
+  <BehaviorTree ID="Constrained Pick and Place" _description="More advanced example of picking and placing an (invisible) object with orientation constraints enforced on the gripper's motion" _favorite="true">
     <Decorator ID="KeepRunningUntilFailure">
       <Control ID="Sequence">
+        <!--Create a special type of motion planning configuration that includes an upwards orientation requirement-->
         <Action ID="InitializeMotionConstraints" constraints_name="gripper pointing down" constraints="{constraints}"/>
         <Action ID="AppendOrientationConstraint" config_file_name="my_constraints.yaml" constraints="{constraints}"/>
-        <Control ID="Sequence" name="TopLevelSequence">
-          <SubTree ID="Open Gripper"/>
-          <Decorator ID="RetryUntilSuccessful" num_attempts="3">
-            <SubTree ID="Move to Waypoint" waypoint_name="Grasp Right" joint_group_name="manipulator" controller_names="/joint_trajectory_controller /robotiq_gripper_controller" planner_interface="moveit_default"/>
-          </Decorator>
-          <SubTree ID="Close Gripper"/>
-          <Decorator ID="RetryUntilSuccessful" num_attempts="3">
-            <SubTree ID="Move to Waypoint" controller_names="/joint_trajectory_controller /robotiq_gripper_controller" joint_group_name="manipulator" waypoint_name="Grasp Left" planner_interface="moveit_all_planners" constraints="{constraints}"/>
-          </Decorator>
-        </Control>
+        <!--Move to pick location-->
+        <SubTree ID="Open Gripper"/>
+        <!--Note: Sampling based planners can be non-deterministic. The retry decorator improves the likelihood of success-->
+        <Decorator ID="RetryUntilSuccessful" num_attempts="3">
+          <SubTree ID="Move to Waypoint" waypoint_name="Grasp Right" joint_group_name="manipulator" controller_names="/joint_trajectory_controller /robotiq_gripper_controller" planner_interface="moveit_default"/>
+        </Decorator>
+        <!--Pick-->
+        <SubTree ID="Close Gripper"/>
+        <!--Move to place (drop) location-->
+        <Decorator ID="RetryUntilSuccessful" num_attempts="3">
+          <SubTree ID="Move to Waypoint" controller_names="/joint_trajectory_controller /robotiq_gripper_controller" joint_group_name="manipulator" waypoint_name="Grasp Left" planner_interface="moveit_default" constraints="{constraints}"/>
+        </Decorator>
       </Control>
     </Decorator>
   </BehaviorTree>