Ros2 control framework unit1 intro, not able to contact service /controller_manager

I just started the ros2 control framework course and the very first ros2 command produces an error:
The command

$ ros2 launch unit1_demo

which is supposed to show a successful load of the controller joint_state_broadcaster instead issues the following message:

could not contact service /controller_manager/load_controller

This is followed by the error report that each of three processes have died.
I have apparently gone through some of this unit before (the progress bar shows 17%) but I wanted to start from the beginning.
Is this something I can fix?

Hello @damien8181,
Thanks for reaching out!

It might be that the simulation on the upper right side of the screen has not fully loaded.

Could you please confirm that the robot is visible before you run that command?

Looking forward to your reply,


Hi Roberto ,
Yeah, it looks like the simulation is not fully loading.
For now I will try refreshing the browser and clearing the cache if that doesn’t work.
If you have any other suggestions, please let me know.
Thanks for your help.

Hi @damien8181, did the simulation fully load for you? Can you see the robot?
I tested it again and there’s no problem on my end.



Hi again Roberto,

Yeah, I was able to load it.
I am now having an issue in Unit 3, thinking about making a new conversation with that one.

Thanks again for the help.


This topic was automatically closed 24 hours after the last reply. New replies are no longer allowed.