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Hello everyone,

I'm trying to use rwt_moveit package alongside with cyton_gamma_300 moveit package on ROS Melodic. I can visualize the robot and the markers on the web page, but as soon I launch the /moveit_publisher node I get this error:

Client [/moveit_publisher] wants topic /move_group/result to have datatype/md5sum [moveit_msgs/MoveGroupActionResult/47ef72f231e49f6059f185fc18418665], but our version has [moveit_msgs/MoveGroupActionResult/6ee8682a508d60603228accdc4a2b30b]. Dropping connection.

So according to what I found in the community, this error occurs when two nodes try to communicate with each other, but from two different ROS environments (like one node from Indigo, and the other one from Kinetic). But in my case, all nodes are in the same ROS environment which is Melodic.

Here is the launch file:

<include file="$(find cyton_gamma_300_moveit_config)/launch/demo.launch"/>

<include file="$(find rosbridge_server)/launch/rosbridge_websocket.launch" />

<node pkg="tf" type="static_transform_publisher" name="connect_start" args="0 0 0 0 0 0 $(arg fixed_frame) /start$(arg fixed_frame) 100" />

<node pkg="tf" type="static_transform_publisher" name="connect_goal" args="0 0 0 0 0 0 $(arg fixed_frame) /goal$(arg fixed_frame) 100" />

<!--node name="tf_web_republisher" pkg="py_tf2_web" type="tf_web_republisher.py" /-->
<node name="tf2_web_republisher" pkg="tf2_web_republisher" type="tf2_web_republisher" />

<node pkg="robot_state_publisher" type="robot_state_publisher" name="start_state_publisher_start">
    <remap from="joint_states" to="start_joint_states" />
    <param name="tf_prefix" type="string" value="start" />
<node pkg="robot_state_publisher" type="robot_state_publisher" name="goal_state_publisher_goal">
    <remap from="joint_states" to="goal_joint_states" />
    <param name="tf_prefix" type="string" value="goal" />

Here are the info about the /move_group/result topic:

rostopic info /move_group/result Type: moveit_msgs/MoveGroupActionResult


  • /move_group (http://laresi-MS-7978:41113/)


  • /moveit_publisher (http://laresi-MS-7978:38973/)
  • /rviz_laresi_MS_7978_6064_4036308910317907203 (http://laresi-MS-7978:43175/)

Can anyone, please, give me some advice or a clue? Thank you very much!

Originally posted by MerAARIZOU on ROS Answers with karma: 3 on 2020-11-08

Post score: 0


1 Answer 1


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This error also occurs if one of your nodes refers to an older message definition than the other. Try cleaning and rebuilding your workspace ( catkin clean -y && catkin build ) and sourcing it in all the terminals ( source devel/setup.bash ). The latter step is important.

Originally posted by fvd with karma: 2180 on 2020-11-10

This answer was ACCEPTED on the original site

Post score: 0

Original comments

Comment by MerAARIZOU on 2020-11-10:
Thank you for your answer . After looking up into the moveit_msgs package, I found out that msgs definitions are different from the source. Actually, I have installed ros-melodic-moveit-msgs from the repos, the package installed in /opt/ros/melodic/... path does contain moveit_msgs/MoveGroupActionResult message, which is not the case if you look into the source code on GitHub https://github.com/ros-planning/moveit_msgs on Melodic branch. I was not able to install the package from source, because of some errors in building other dependencies. I wonder why the two versions are so different, eventhough they are both for Melodic?

Comment by fvd on 2020-11-10:
.action files are generated into Request Result and Feedback messages, so the message you see is based on this action. It would look the same if you built it locally. You can also build moveit from source if this doesn't work.


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