condition distance traveled always returns failure

[guidout]

Since when the behavior tree is first loaded, all nodes are in the IDLE state before they are ticked for the first time, doesn't this if statement always return IDLE and therefore the tick method always return FAILURE?

navigation2/nav2_behavior_tree/plugins/condition/distance_traveled_condition.cpp

Line 46 in 507b365

if (status() == BT::NodeStatus::IDLE) {

I also asked the question here but didn't get answers:
https://robotics.stackexchange.com/questions/114059/nav2-distance-traveled-condition

[SteveMacenski]

Please do not cross post.

Have you actually tried to use it and see that it doesn't work or just speculating looking at the software? We have a unit test that seems to point to it working [1]

[1] https://github.com/ros-navigation/navigation2/blob/main/nav2_behavior_tree/test/plugins/condition/test_distance_traveled.cpp

[guidout]

Yes, I did test it and the condition always returns IDLE.
This is the BT I used for the test:

<root main_tree_to_execute="MainTree">
  <BehaviorTree ID="MainTree">

    <RateController hz="1.0">
      <ReactiveFallback name="CheckDistanceTravelled">
        <DistanceTraveled distance="2.0" global_frame="map" robot_base_frame="base_link"
        />

        <PipelineSequence>
          <GoalUpdatedController>
            <RecoveryNode number_of_retries="1" name="RecoveryComputePathToPose">
              <ComputePathToPose goal="{goal}" path="{path}"
                planner_id="GridBased_SmacHybrid_production_line" />
              <ClearEntireCostmap name="ClearGlobalCostmap-Context"
                service_name="global_costmap/clear_entirely_global_costmap" />
            </RecoveryNode>
          </GoalUpdatedController>
          <RecoveryNode number_of_retries="1" name="RecoveryFollowPath">
            <FollowPath path="{path}" controller_id="FollowPath_TEB_prod_line"
              goal_checker_id="general_goal_checker" />
            <ClearEntireCostmap name="ClearLocalCostmap-Context"
              service_name="local_costmap/clear_entirely_local_costmap" />
          </RecoveryNode>
        </PipelineSequence>
      </ReactiveFallback>
    </RateController>
  </BehaviorTree>
</root>

I added a print out in the distance_traveled_condition.cpp:

BT::NodeStatus DistanceTraveledCondition::tick()
{
    std::cout << "Distance Traveled Condition Status: " << status()
              << std::endl;

    if (status() == BT::NodeStatus::IDLE)
...

It always prints IDLE.

Maybe my behavior tree does not implement this condition correctly?

[SteveMacenski]

Can you check the test and see an error? Unfortunately, we're a bit resource constrained right now, so I do need developers to do a bit of research to help suss out their issues (if they exist). I don't have the bandwidth right now to dig into each reported issue from scratch :-)

I see that the main version of this node looks different from the link that you provided based on some hash. What branch is that from, how did you obtain that hash, and have you tested any changes as addressing the behavior (and/or looked at main for potential updates)?

It could be that your hash is from a no longer supported branch / distribution -- or based on BT.CPPv3, and we're on BT.CPPv4 now that has different behavior and definitions for states

[guidout]

That hash should be the latest commit from the Humble branch.
I'll do some digging and report back.
I understand your resource constraints, totally. Thanks for replying, I'll report back as I find out more.