/cmd_vel no subscribers

[dmorris0]

Robot Model

Turtlebot4 Lite

ROS distro

Humble

Networking Configuration

Discovery Server

OS

Ubuntu 22.04

Built from source or installed?

Installed

Package version

ubuntu@ubuntu:~$ dpkg -s ros-$ROS_DISTRO-turtlebot4-PACKAGE_WITH_ISSUE
dpkg-query: package 'ros-humble-turtlebot4-package_with_issue' is not installed and no information is available
Use dpkg --info (= dpkg-deb --info) to examine archive files.

Type of issue

Other

Expected behaviour

When I publish to /cmd_vel, or use teleop, I expect the bot to move.

Actual behaviour

My turtlebot does not respond to Teleop or /cmd_vel. When I view info on the /cmd_vel topic I see that it has a publisher but no subscriber -- I expect it to have a subscriber and no publisher as I'm not publishing anything. On the Turtlebot I get:

~$ ros2 topic info /cmd_vel
Type: geometry_msgs/msg/Twist
Publisher count: 1
Subscription count: 0

From my PC, I get 2 publishers:

~$ ros2 topic info /cmd_vel
Type: geometry_msgs/msg/Twist
Publisher count: 2
Subscription count: 0

I can see contents of other topics, like /tf fine.

Error messages

No response

To Reproduce

I installed the latest firmware on the Create and did a factory reset.

I reinstalled the latest RPi image like here: https://turtlebot.github.io/turtlebot4-user-manual/setup/basic.html#install-latest-raspberry-pi-image

I followed all the instructions on setting up the Discovery Server here: https://turtlebot.github.io/turtlebot4-user-manual/setup/discovery_server.html

Other notes

No response

[smatarCPR]

Hello @dmorris0
Thank you for reaching out on the Turtlebot 4 Github page. I am very sorry to hear you are having an issue with one of our products.

I notice that you are using a discovery server setup, have you added an namespace to your environment or is there no namespace? If you have not yet implemented a namespace, it is strongly recommended you do.

If after implementing a namespace, the issue still persists send the turtlebot logs generated by the command: journalctl -b > turtlebot4_log.txt

Let me know how this recommendation works for you. Looking forward to hearing from you soon.
Best Regards,
Saif

[dmorris0]

@smatarCPR Thank you for the namespace suggestion. When I set the namespace, then the new cmd_vel with namespace had a subscriber and I could control the Turtlebot!