expected [string_array] got [string] - Move_group

[Ep3896]

Good evening! I'm using ROS2 Humble and I'm working on a Lite6 project. After installing Moveit2 from source and right after launching:

ros2 launch xarm_planner lite6_planner_fake.launch.py

I've noticed that the move_group node dies and so i can't perform the motion planning on my robot.

I was wondering what could I do to fix the error. I've check on the moveit documentiation and see that:

"Warning: Most features in MoveIt will not work properly since additional parameters are required for full Move Group functionality. For a full setup, please continue with the [Move Group C++ Interface Tutorial]"

If anyone could give me advice on how to go through , I would be very pleased!

Thank you in advance, Enrico

[gaspatxo]

1. Make sure you follow the preparation and installation instructions from the xarm_ros2 readme file strictly
2. I had to reboot before being able to use the package (It could be the same issue but I do not remember)

[Ep3896]

I can actually use the package, the problem is that the parameters are not correct, I think that there are parameters that need to be set or unset in order to let the program correctly go through. Maybe it is just an installation mistake but i really doubt about it

[gaspatxo]

You are using Ubuntu 22.04, right? Is it a fresh installation or have you used it for other developing purposes?

Did you succesfully run the moveit2 tutorials?

Did you try using the package post-reboot after the installation session?

I ran the command on my setup, you can check the CLI output. As you can see the error you mention is not there.

[Ep3896]

First of all, I appreciate your help! :D I think there are problems with the planning_pipeline. I don't know yet how to solve this problem but I think there are issues with passing parameters to move group. For parameters I mean the planners, because I see that where my program crushes, yours instead say:

[move_group-4] [INFO] [1712390116.696721151] [moveit.ros_planning_interface.moveit_cpp]: Loading planning pipeline 'ompl' [move_group-4] [INFO] [1712390116.723966080] [moveit.ros_planning.planning_pipeline]: Using planning interface 'OMPL'

So I really need to check how it is possible to fix that problem. Maybe it's a yaml problem? or maybe in the launch file? I am figuring out but if someone can help me I would really be grateful!

[Ep3896]

Of course! this is the log error: here

As for Rviz, this is the log on the window:

So the issue, I suppose, is that the planning pipeline yaml is not correct, but this is just my interpretation. I really trying to understand how to fix that but without great outcomes yet.

[vimior]

@Ep3896 I compared it and found that you did not load the output related to planning_pipeline and the abnormality is that the type of a certain configuration parameter is wrong. Have you modified anything?

[Ep3896]

I don't think so! However, I was able to point out where the program crashes:

ros2 launch xarm_moveit_config _robot_moveit_common.launch.py

this launch file gives me the error but I'm trying to figure out why.

[vimior]

@Ep3896 Running _robot_moveit_common.launch.py alone is incomplete. You can run lite6_moveit_fake.launch.py to find the problem.

ros2 launch xarm_moveit_config lite6_moveit_fake.launch.py

[Ep3896]

yes! but I have already run :

ros2 launch xarm_moveit_config lite6_moveit_fake.launch.py

But I have the exact same error! Could it be libmoveit_planning_pipleline.so.2.9? I'm running out of ideas, if you could provide to me, however your log of this:

ros2 launch xarm_moveit_config lite6_moveit_fake.launch.py

I would be really pleased :)

Thank you in advance!

[vimior]

@Ep3896 This kind of missing libmoveit_planning_pipleline.so.2.9 is usually caused by incomplete system updates. You may need to obtain updates from a stable source. In addition, the humble version here is libmoveit_planning_pipleline.so.2.5.5, and the rolling version is libmoveit_planning_pipleline.so.2.9.0

[vimior]

@Ep3896 Maybe the problem lies in the libmoveit_planning_pipleline.so.2.9 version. This problem will also occur when I run it under the rolling version. I will look for the problem first.

[vimior]

@Ep3896 Hello, I looked through the moveit code and found that the configuration format has changed. Please refer to the pr for details.

You can temporarily modify the xarm_moveit_config/launch/_robot_moveit_common.launch.py file to use, we will fix this problem later. Search for the definition of ompl_planning_pipeline_config, and then modify it to the following format

ompl_planning_pipeline_config = {
    'default_planning_pipeline': 'ompl',
    'planning_pipelines': ['ompl'],
    'ompl': {
        'planning_plugins': ['ompl_interface/OMPLPlanner'],
        'request_adapters': [
            'default_planning_request_adapters/ResolveConstraintFrames',
            'default_planning_request_adapters/ValidateWorkspaceBounds',
            'default_planning_request_adapters/CheckStartStateBounds',
            'default_planning_request_adapters/CheckStartStateCollision',
        ],
        'response_adapters': [
            'default_planning_response_adapters/AddTimeOptimalParameterization',
            'default_planning_response_adapters/ValidateSolution',
            'default_planning_response_adapters/DisplayMotionPath',
        ],
    }
}

[Ep3896]

Thank you very much! I have learnt a lot :) Greetings!

[vimior]

@Ep3896

This change is in the main branch of moveit and has not been applied to humble and iron, i am not sure why the humble version you are using has this change. Is the moveit you are using installed from the main branch of the source code?

Our update adds detection of the current ROS version. Versions after iron will use the new configuration (note: humble still uses the original configuration, which may not be compatible with your situation)

[Ep3896]

I have installed Moveit2 from the main branch because they textually say:

Currently the main branch supports Rolling, Iron, and Humble. However, since it’s used for latest development, the main branch is unstable. For stable versions, please use the distro branches humble, or iron.

And my goal is to actually keep up with the latest developments, even if they are unstable.

Btw, Thank you very much for helping me out!