[BUG] {connection and nodes issue}

[JJJ2777]

The connection between my PC an turlebot4 doesn't work correctly. I have: ubuntu 20.04, Ros2 Galactic and the Turlebot4 lite with the create 3 and on the turlebot4 is a raspberry pi 4

I have the simple discovery for the Networking, so my PC, Turtlebot4 and my raspberry are all in the same WI-FI.

When I don`t launch something manual these are my lists:

on the PC:

ros2 topic list /battery_state /color/preview/camera_info /color/preview/image /diagnostics /diagnostics_agg /diagnostics_toplevel_state /dock /hazard_detection /imu /interface_buttons /ip /joint_states /joy /mouse /parameter_events /robot_description /rosout /scan /stereo/camera_info /stereo/depth /tf /tf_static /wheel_status

ros2 node list

on my Turtlebot4:

ros2 topic list /battery_state /cmd_audio /cmd_lightring /cmd_vel /color/preview/camera_info /color/preview/image /diagnostics /diagnostics_agg /diagnostics_toplevel_state /dock /hazard_detection /imu /interface_buttons /ip /ir_intensity /ir_opcode /joint_states /joy /kidnap_status /mobility_monitor/transition_event /mouse /odom /parameter_events /robot_description /robot_state/transition_event /rosout /scan /slip_status /static_transform/transition_event /stereo/camera_info /stereo/depth /stop_status /tf /tf_static /wheel_status /wheel_ticks /wheel_vels

ros2 node list /_internal/composite_hazard /_internal/kinematics_engine /_internal/mobility /_internal/stasis /analyzers /mobility_monitor /motion_control /rgb_stereo_node /robot_state /robot_state_publisher /rplidar_composition /static_transform /system_health /turtlebot4_diagnostics /turtlebot4_node /ui_mgr

My problem: I can’t see or use the nodes from my Turtlebot4. I downloaded everything with their dependencies successful. But I can’t drive my Turtlebot4 with my PC and Keyboard Teleoperation or Command Velocity only directly with the Raspberry. For example when I want to dock my Turtlebot4 with my PC with:

ros2 action send_goal /dock irobot_create_msgs/action/DockServo {}

it only says: Waiting for an action server to become available... all the time but nothing happens, it only worked directly from my Turtlebot with the Raspberry

Also I can sometimes see diagnostic data from my Turtlebot4 on my PC when i manually launch on my Turtlebot4:

ros2 launch turtlebot4_diagnostics diagnostics.launch.py

And then I launch on my PC:

ros2 launch turtlebot4_viz view_diagnostics.launch.py

Then I get this node list on the PC:

ros2 node list /analyzers /robot_monitor_log_node /rqt_gui_py_node_20110 /timeline_log_node /timeline_subscriber /turtlebot4_diagnostics

And this is my diagnostic window:

When I also Launch:

ros2 launch turtlebot4_bringup oakd.launch.py ros2 launch turtlebot4_bringup rplidar.launch.py

Then I get this Node list on my PC:

ros2 node list /rgb_stereo_node /robot_monitor_log_node /rplidar_composition /rqt_gui_py_node_20110 /timeline_log_node /timeline_subscriber

(sometimes there are the same nodes twice and I get a warning message about it, because duplication of names can lead to problems)

and my diagnostic Window looks like this:

A few days ago when I launched it manually and the camera worked but now it doesn’t record any events anymore.

And the IMU has the Problem that the frequency is to high but I also don’t know how to change that.

[Serafadam]

Hi, I guess this is related more to Turtlebot stack itself, but if I remember correctly, supported ROS2 version is Humble, could you check if that one works for you?

[JJJ2777]

Yeah, I think I put it in the wrong stack. I can't change it, because we are using Galactic at my university. Does ROS2 only work with Humble?

[Serafadam]

Hi, since Galactic is EOL, I'd recommend asking on Turtlebot repository what would be the recommended steps here, when it comes to the driver itself I would either build it from source (you can use Foxy branch for that) or try using one of Docker images to run it separately and see if that works out.

[JJJ2777]

Thank you for your help, I fixed the problem by changing _RMW_IMPLEMENTATION=rmw_cycloneddscpp to _RMW_IMPLEMENTATION=rmw_fastrtpscpp.