enable isForkliftLoadDetected condition node (ros-navigation#234)

* enable isForkliftLoadDetected condition node

* use check_forklift_load_state argument and remove wait

Author: liyuanlogi

nav2_bt_navigator/behavior_trees/pallet_pickup.xml

@@ -7,10 +7,7 @@
   <BehaviorTree ID="PalletPickUpMasterBT">
     <RetryUntilSuccessful num_attempts="2">
       <Sequence>
-        <!-- <Wait wait_duration="2"/>
-        <Inverter>
-          <isForkliftLoadDetected/>
-        </Inverter>  -->
+        <isForkliftLoadDetected check_forklift_load_state="empty"/>
         <Fallback>
           <Sequence>
             <AGVCloseToPallet goal="{goal}" pallet_id="{pallet_id}"/>

nav2_bt_navigator/behavior_trees/pallet_pickup_without_obstacles.xml

@@ -49,7 +49,7 @@
             </RecoveryNode>
             <AlwaysSuccess/>
           </Fallback>
-          <!--<isForkliftLoadDetected/>-->
+          <isForkliftLoadDetected check_forklift_load_state="loaded"/>
           <SetLiftLevel lift_level="lifted_low" wait_for_lift="True" lift_timeout="10.0"/>
           <Parallel name="lift while backup" failure_threshold="1" success_threshold="2">
             <BackUp backup_dist="1.8" backup_speed="0.3"/>

nav2_bt_navigator/behavior_trees/pallet_pickup_without_obstacles_and_lidar.xml

@@ -28,8 +28,7 @@
                         </RetryUntilSuccessful>
                         <CallService service_name="stop_barcode_scanning_1"/>
                         <CallService service_name="stop_barcode_scanning_2"/>
-                        <!-- After forklift publisher will be operated, node below should be uncommented -->
-                        <!-- <isForkliftLoadDetected/> -->
+                        <isForkliftLoadDetected check_forklift_load_state="loaded"/>
                         <SetLiftLevel lift_level="lifted_low"/>
                     </Sequence>
                 </ReactiveSequence>

nav2_bt_navigator/behavior_trees/pallet_putdown.xml

@@ -6,8 +6,7 @@
   <BehaviorTree ID="PalletPutDownMasterBT">
     <RetryUntilSuccessful num_attempts="2">
       <Sequence>
-        <!-- <Wait wait_duration="2"/>
-        <isForkliftLoadDetected/> -->
+        <isForkliftLoadDetected check_forklift_load_state="loaded"/>
         <Fallback name="leave bin">
           <Sequence name="leave the bin">
             <!-- add_narrow_exit_waypoint-->