Launching nav2_bringup tb3_simulation_launch.py - Gazebo can't find Child Link[camera_rgb_frame]

[Darkproduct]

Bug report

Required Info:

• Operating System:
  Ubuntu 20.04
• ROS2 Version:
  Foxy binaries
• Version or commit hash:
  ros-foxy-navigation2 0.4.7-1focal.20210701.023143
• DDS implementation:
  Fast-RTPS

Steps to reproduce issue

https://navigation.ros.org/getting_started/index.html#running-the-example

source /opt/ros/<ros2-distro>/setup.bash
export TURTLEBOT3_MODEL=waffle
export GAZEBO_MODEL_PATH=$GAZEBO_MODEL_PATH:/opt/ros/<ros2-distro>/share/turtlebot3_gazebo/models
// Add --verbose to the gzserver in the launch file.
// Either change it directly or copy it and run it afterwards with
// ros2 launch tb3_simulation_launch.py
ros2 launch nav2_bringup tb3_simulation_launch.py

Result:

[gzserver-1] [Msg] Waiting for master.
[gzserver-1] [Msg] Connected to gazebo master @ http://127.0.0.1:11345
[gzserver-1] [Msg] Publicized address: 192.168.122.20
[gzserver-1] [Msg] Loading world file [/opt/ros/foxy/share/nav2_bringup/worlds/waffle.model]
[gzserver-1] [Err] [Joint.cc:297] EXCEPTION: Couldn't Find Child Link[camera_rgb_frame]
[gzserver-1] 
[gzserver-1] [Err] [Model.cc:272] LoadJoint Failed

Expected behavior

Running without errors

Actual behavior

Gazebo can't load the broken waffle.model from nav2_bringup.

Possible fixes

Temporary solution

Use:

ros2 launch tb3_simulation_launch.py world:=/opt/ros/foxy/share/turtlebot3_gazebo/worlds/turtlebot3_worlds/waffle.model

Real fix

Change this back (in tb3_simulation_launch.py):
From:

declare_world_cmd = DeclareLaunchArgument(
        'world',
        # TODO(orduno) Switch back once ROS argument passing has been fixed upstream
        #              https://github.com/ROBOTIS-GIT/turtlebot3_simulations/issues/91
        # default_value=os.path.join(get_package_share_directory('turtlebot3_gazebo'),
        #                            'worlds/turtlebot3_worlds/waffle.model'),
        default_value=os.path.join(bringup_dir, 'worlds', 'waffle.model'),
        description='Full path to world model file to load')

To:

declare_world_cmd = DeclareLaunchArgument(
        'world',
        # ??? TODO(orduno) Switch back once ROS argument passing has been fixed upstream
        # ???             https://github.com/ROBOTIS-GIT/turtlebot3_simulations/issues/91
        default_value=os.path.join(get_package_share_directory('turtlebot3_gazebo'),
                                   'worlds/turtlebot3_worlds/waffle.model'),
        description='Full path to world model file to load')

[SteveMacenski]

a PR to add that link to the model file in nav2_bringup/worlds would be appreciated. Right now we're in the mid-stages of removing dependencies on the TB3 so I don't want to add another dependency by changing the world from our version of the TB3 world to the Robotis version.

[Darkproduct]

Ok, np. Should I just copy to the waffle.model from the TB3 over, or revert to the previus option to just open the model from the tb3_worlds?

[SteveMacenski]

No, I think you just need to add that frame that was missing (or remove the other frames that depend on it if not being used). We have some changes in the model file that should not be wiped out with the TB3's

[Darkproduct]

Ok. I'll have a look then.