[ERROR] [1636805101.138944786]: Failed to build tree: child link [front_camera] of joint [front_camera_bracket_joint] not found

[dongmingli-Ben]

Thanks for your great work!
I ran the command roslaunch rm_simulator ridgeback_robots.launch following the instructions in README and ran into the above error with ROS version being Neotic. However, earlier I did almost the same thing on Melodic and no error occurs. As I am new to ROS and gazebo, could you please provide some help on how to resolve this issue?

Expected Outcome:
No error, four robots appear on the map.

Ubuntu version: 20.04
ROS version: Noetic

Error trace:

... logging to /home/decision/.ros/log/eca6f67e-4479-11ec-9874-0f9a2375c8c2/roslaunch-jakeluo-labpc-105471.log
Checking log directory for disk usage. This may take a while.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

xacro: in-order processing became default in ROS Melodic. You can drop the option.
xacro: in-order processing became default in ROS Melodic. You can drop the option.
xacro: in-order processing became default in ROS Melodic. You can drop the option.
xacro: in-order processing became default in ROS Melodic. You can drop the option.
started roslaunch server http://jakeluo-labpc:37863/
......
etting /run_id to eca6f67e-4479-11ec-9874-0f9a2375c8c2
process[rosout-1]: started with pid [105501]
started core service [/rosout]
process[gazebo-2]: started with pid [105508]
process[gazebo_gui-3]: started with pid [105512]
process[map_server-4]: started with pid [105518]
process[jackal0/urdf_spawner-5]: started with pid [105519]
process[jackal0/robot_state_publisher-6]: started with pid [105520]
process[jackal0/controller_spawner-7]: started with pid [105521]
process[jackal0/ekf_localization-8]: started with pid [105522]
process[jackal0/cmd_vel_relay-9]: started with pid [105523]
process[jackal0/turret_controller-10]: started with pid [105525]
process[jackal0/global_planner_node-11]: started with pid [105539]
process[jackal0/local_planner_node-12]: started with pid [105543]
process[jackal0/behavior_test_node-13]: started with pid [105546]
[ERROR] [1636805100.934693031]: Failed to build tree: child link [front_camera] of joint [front_camera_bracket_joint] not found
......
process[jackal3/localization_node-44]: started with pid [105702]
process[simulate_refer_system-45]: started with pid [105705]
process[ridgeback_viz_jackal0-46]: started with pid [105709]
[ INFO] [1636805101.127980623]: !!!!!!!!!!!decision jackal_ns:jackal2
[ INFO] [1636805101.131774334]: !!!!!!!!!!!global jackal_ns:jackal0
[ INFO] [1636805101.131806940]: !!!!!!!!!!!jackal_number:0
[ERROR] [1636805101.138944786]: Failed to build tree: child link [front_camera] of joint [front_camera_bracket_joint] not found
......
[ INFO] [1636805101.148674883]: !!!!!!!!!!!decision jackal_ns:jackal3
[ INFO] [1636805101.158665933]: Load prototxt: /home/decision/decision/workspace/RoboMaster-Simulator/src/RoboRTS/roborts_planning/global_planner/config/global_planner_config.prototxt
[ INFO] [1636805101.182189451]: local planner start
[ERROR] [1636805101.199338900]: Failed to build tree: child link [front_camera] of joint [front_camera_bracket_joint] not found
[ INFO] [1636805101.232287005]: Load prototxt: /home/decision/decision/workspace/RoboMaster-Simulator/src/RoboRTS/roborts_planning/local_planner/config/local_planner.prototxt
[ INFO] [1636805101.250654186]: local planner start
[ INFO] [1636805101.254549442]: Load prototxt: /home/decision/decision/workspace/RoboMaster-Simulator/src/RoboRTS/roborts_planning/global_planner/config/global_planner_config.prototxt
[ERROR] [1636805101.259904003]: Failed to build tree: child link [front_camera] of joint [front_camera_bracket_joint] not found
......
[ INFO] [1636805101.421957796]: waitForService: Service [/static_map] has not been advertised, waiting...
[ INFO] [1636805101.430659859]: waitForService: Service [/static_map] has not been advertised, waiting...
[ INFO] [1636805101.432417707]: waitForService: Service [/static_map] has not been advertised, waiting...
[jackal0/robot_state_publisher-6] process has died [pid 105520, exit code 1, cmd /opt/ros/noetic/lib/robot_state_publisher/robot_state_publisher __name:=robot_state_publisher __log:=/home/decision/.ros/log/eca6f67e-4479-11ec-9874-0f9a2375c8c2/jackal0-robot_state_publisher-6.log].
log file: /home/decision/.ros/log/eca6f67e-4479-11ec-9874-0f9a2375c8c2/jackal0-robot_state_publisher-6*.log
[jackal1/robot_state_publisher-16] process has died [pid 105564, exit code 1, cmd /opt/ros/noetic/lib/robot_state_publisher/robot_state_publisher __name:=robot_state_publisher __log:=/home/decision/.ros/log/eca6f67e-4479-11ec-9874-0f9a2375c8c2/jackal1-robot_state_publisher-16.log].
log file: /home/decision/.ros/log/eca6f67e-4479-11ec-9874-0f9a2375c8c2/jackal1-robot_state_publisher-16*.log
[ INFO] [1636805101.483923939]: Finished loading Gazebo ROS API Plugin.
[ INFO] [1636805101.484642078]: waitForService: Service [/gazebo/set_physics_properties] has not been advertised, waiting...
[ INFO] [1636805101.565834622]: Finished loading Gazebo ROS API Plugin.
[ INFO] [1636805101.566584950]: waitForService: Service [/gazebo_gui/set_physics_properties] has not been advertised, waiting...
[jackal2/robot_state_publisher-26] process has died [pid 105616, exit code 1, cmd /opt/ros/noetic/lib/robot_state_publisher/robot_state_publisher __name:=robot_state_publisher __log:=/home/decision/.ros/log/eca6f67e-4479-11ec-9874-0f9a2375c8c2/jackal2-robot_state_publisher-26.log].
log file: /home/decision/.ros/log/eca6f67e-4479-11ec-9874-0f9a2375c8c2/jackal2-robot_state_publisher-26*.log
[jackal3/robot_state_publisher-36] process has died [pid 105652, exit code 1, cmd /opt/ros/noetic/lib/robot_state_publisher/robot_state_publisher __name:=robot_state_publisher __log:=/home/decision/.ros/log/eca6f67e-4479-11ec-9874-0f9a2375c8c2/jackal3-robot_state_publisher-36.log].
log file: /home/decision/.ros/log/eca6f67e-4479-11ec-9874-0f9a2375c8c2/jackal3-robot_state_publisher-36*.log
[ERROR] [1636805102.826106674]: Failed to build tree: child link [front_camera] of joint [front_camera_bracket_joint] not found
[ERROR] [1636805102.827634362]: Failed to build tree: child link [front_camera] of joint [front_camera_bracket_joint] not found
[ERROR] [1636805102.831515666]: Failed to build tree: child link [front_camera] of joint [front_camera_bracket_joint] not found
[ERROR] [1636805102.832738008]: Failed to build tree: child link [front_camera] of joint [front_camera_bracket_joint] not found
[ INFO] [1636805103.064505345]: waitForService: Service [/gazebo/set_physics_properties] is now available.
[ INFO] [1636805103.077927275, 5775.864000000]: Physics dynamic reconfigure ready.
Error [parser_urdf.cc:3183] Unable to call parseURDF on robot model
Error [parser.cc:488] parse as old deprecated model file failed.

[yizhengzhang1]

Hi,
It is not tested in ROS Noetic version. You can go through the URDF files to fix this problem. I think there is something updated in ROS Noetic when parsing URDF files.

It is appreciated to fix this problem and create a pull requests.

[dongmingli-Ben]

Thanks for your feedback. After googling around, I find that it is because Noetic forbids the lack of namespace in xacro, as in this question. I successfully solve this problem after adding xacro: to every tag that lacks it.

However, another problem pops up, which shows the error message

E1114 14:51:45.012620 185069 localization_node.cpp:279] Couldn't transform from center_laserto /jackal3/base_link

I notice that this problem may lie in the roborts package. Could you please give some instructions on how to solve this problem?

[dongmingli-Ben]

Just a following up comment, it seems that the cause of the above problem is that the center_lazer or scan is somehow broken. Still, I have no clue on how to solve it.

[yizhengzhang1]

Hi,
This may be related to the Lidar sensor. Maybe the link or joint's name is wrong due to the difference of parse xarco file in Noetic.

[marcopra]

Hi @dongmingli-Ben , do you have the code adapted to work with ROS Noetic? Can I contact you to share it?