Add example of using multiple controller managers under different namespaces.

[destogl]

No description provided.

[jackcenter]

This doesn't seem to be working on my system. After checking out this branch, the initial demo doesn't work as expected. If I run: ros2 launch ros2_control_demo_bringup rrbot.launch.py
then: `ros2 control list_hardware_interfaces '
I get:

command interfaces
	joint1/position [unclaimed]
	joint2/position [unclaimed]
state interfaces
	 joint1/position
	 joint2/position

and running: ros2 control list_hardware_interfaces
doesn't return anything anymore.
This demo works as expected if I checkout master

Also, running: ros2 launch ros2_control_demo_bringup rrbot_namespace.launch.py
brings up rrbot in rviz, but then running :ros2 control list_hardware_interfaces
returns: Could not contact service /controller_manager/list_hardware_interfaces
and running: ros2 control list_controllers
returns: Could not contact service /controller_manager/list_controllers

[destogl]

@jackcenter

Thanks for the review!

It seems that I have broke rrbot.launch.py example. I just fixed this, and it should work again now. I had some unintentional change still in the code.

Nevertheless, the “namespace” examples are updated, i.e., manual is updated, can you please check one more time? (I don't want to give you further details to “simulate” how a new user would approach the examples. — I am glad to give them to you after test if you are interested, but hopefully the README should be sufficient.)

And yes, this works currently only when ros2_control and ros2_controllers are compiled from source and with newest rolling on 22.04.

[jackcenter]

Looks like everything works, and the simulations look cool! I wrote a few thoughts about the README organization.

[jackcenter]

Presentation thought: this doesn't output the commands as the forward_position_controller does, which may be confusing for new users. It's easy enough to echo the topic it tells you it's publishing on, but it might be a nice addition to output the commands for the demo.

[destogl]

This is something we should update then in the ros2_controllers_test_nodes (here. Is this something you would be interested to do?

[jackcenter]

Sure! I'll create an issue and take a look this week.

[jackcenter]

Random question: why does this file include the joints but ros2_control_demo_bringup/config/multi_controller_manager_forward_position_publisher.yaml doesn't?

[destogl]

Because different type of publisher nodes are used and therefore different type of messages are published. Commands for JointTrajectoryController need to have joint names.

This file configures this publisher node.

The above one configured this node.

[destogl]

Looks like everything works, and the simulations look cool! I wrote a few thoughts about the README organization.

@jackcenter thanks for the thorough review!

[mergify]

This pull request is in conflict. Could you fix it @destogl?

[christophfroehlich]

Closing in favor of #423