TF Tree on different topic name

[xkaraman]

Describe the bug I don't know where to report this for now, so i will just report it to its digital twin.

I have the Create 3 robot and on i have configured it through its' webserver to have a namespace say /robot1.

I can see the topics have indeed pushed down to it but one concern is that /tf and /tf_static/ are also pushed down i.e /robot1/tf and /robot1/tf_static.

Generally as far as i know /tf and /tf_static should be on global namespace and the frame-names instead should be pushed to a different ie /robot1/odom frame.

I would like to know if my thinking is wrong and how i can keep the namespace but have my tf tree correctly, so i can publish other transforms like lidar or camera frame in relation to say base_link frame.

Available topics: /robot1/tf should be still /tf but with frames like /robot1/odom etc. ( Correct me if i am wrong)

/parameter_events
/robot1/battery_state
/robot1/cmd_audio
/robot1/cmd_lightring
/robot1/cmd_vel
/robot1/dock
/robot1/hazard_detection
/robot1/imu
/robot1/interface_buttons
/robot1/ir_intensity
/robot1/ir_opcode
/robot1/kidnap_status
/robot1/mobility_monitor/transition_event
/robot1/mouse
/robot1/odom
/robot1/robot_state/transition_event
/robot1/slip_status
/robot1/static_transform/transition_event
/robot1/stop_status
/robot1/tf
/robot1/tf_static
/robot1/wheel_status
/robot1/wheel_ticks
/robot1/wheel_vels
/rosout

Additional Context https://github.com/iRobotEducation/create3_sim/pull/176#issuecomment-1185764666 Seems to have it right for the draft but on real robot is not like that.

[justinIRBT]

See the discussion here: https://github.com/iRobotEducation/create3_docs/discussions/39

[xkaraman]

Ok, thanks for the link. Got the reasoning but as far i can see there is https://github.com/ros/robot_state_publisher/commit/b85516011473747771ca7b986489e6e127b5340c that address the problem?

So what's the best way to handle it as far as you know? Should i just drop the namespace for now?

[justinIRBT]

If you had a multi-robot use case, you could subscribe to the separate topics /robot1/tf /robot2/tf then make a TransformBroadcaster with the frames renamed to robot1/frame1 and robot2/frame1, etc... in the standard tf tree

[xkaraman]

Ok thanks for the information and help!