Copter: use 3DoF gimbal

[srmainwaring]

Change the Iris model to use the 3DoF gimbal.

Dependencies

• Port #102 to ros2 ardupilot_gazebo#124

Testing

Launch simulation

ros2 launch ardupilot_gz_bringup iris_runway.launch.py console:=True

and start a mavproxy interactive session to control:

mavproxy.py --master :14550
 
STABILIZE> mode guided
GUIDED> arm throttle
GUIDED> takeoff 2
GUIDED> Take Off started
GUIDED> rc 3 1500
GUIDED> circle

• The model appears correctly in Gazebo.
• The model appears correctly in rviz.
• The 3DoF gimbal links are visible in rviz2.
• The camera topic is relayed from Gazebo to ROS 2.

[Ryanf55]

For some reason, I do not get synthetic video, and rviz doesn't show the vehicle frame.

In CLI, I see [Wrn] [ArduPilotPlugin.cc:1585] ArduPilot controller has reset 3 times in the logs.

[srmainwaring]

For some reason, I do not get synthetic video, and rviz doesn't show the vehicle frame.

@Ryanf55, I've just checked on an Ubuntu 22.04 VM (Gazebo Harmonic and ROS 2 Humble) - and is working after checking out the two branches and rebuilding. Can you please post the launch terminal log to help trace what might be going on.

[Ryanf55]

ardupilot_gz_logs.txt
frames_2024-10-30_18.15.35.pdf

There's no /tf data or /tf_static data.

[srmainwaring]

There's no /tf data or /tf_static data.

The problem is here:

[robot_state_publisher-6] [ERROR] [1730333584.404356089] [sdformat_urdf]: Failed to find sdf canonical link [base_link]
[robot_state_publisher-6] Failed to parse robot description using: sdformat_urdf_plugin/SDFormatURDFParser
[robot_state_publisher-6] terminate called after throwing an instance of 'std::runtime_error'
[robot_state_publisher-6]   what():  Unable to initialize urdf::model from robot description

Now I'm not sure why that is an issue on your install. It could be related to #49?

Edit if I check out the main branch of ardupilot_gazebo rather than ros2, and re-run, I see this error:

[robot_state_publisher-6] [ERROR] [1730370408.367511000] [sdformat_urdf]: Failed to find sdf canonical link [base_link]
[robot_state_publisher-6] [WARN] [1730370408.367654000] [urdf]: Failed to parse robot description using: sdformat_urdf_plugin/SDFormatURDFParser
[robot_state_publisher-6] 
[robot_state_publisher-6] libc++abi: terminating due to uncaught exception of type std::runtime_error: Unable to initialize urdf::model from robot description
[ERROR] [robot_state_publisher-6]: process has died [pid 87187, exit code -6, cmd '/Users/rhys/Code/ros2/rolling/ros2-rolling/install/robot_state_publisher/lib/robot_state_publisher/robot_state_publisher --ros-args -r __node:=robot_state_publisher --params-file /var/folders/_y/7tf19g6j2wgclxfy1m3nrr9m0000gn/T/launch_params_xo4lzeen --params-file /var/folders/_y/7tf19g6j2wgclxfy1m3nrr9m0000gn/T/launch_params_i4hxw6i3'].

This is because sdformat_urdf can only resolve SDF <uri> elements that use the package:// prefix, which is a ROS construct rather than something native to Gazebo.

One possibility is that your build / install is using the wrong branch of ardupilot_gazebo, or that an iris_with_gimbal model using the model:// prefix in the <uri> is present in the GZ_SIM_RESOURCE_PATH.

[Ryanf55]

I checked all branches and fixed using the wrong ardupilot_gazebo branch. Once I do that, the vehicle can takeoff and circle, however the gimbal doesn't seem to be controlled.

Nothing seems wrong in the logs other than periodic warnings on the ArduPilot controller has reset periodically. robot_state_publisher is running.

[srmainwaring]

the gimbal doesn't seem to be controlled

Does the gimbal respond to rc commands? The following should centre it.

> rc 6 1500
> rc 7 1500
> rc 8 1500

[Ryanf55]

the gimbal doesn't seem to be controlled

Does the gimbal respond to rc commands? The following should centre it.

> rc 6 1500
> rc 7 1500
> rc 8 1500

With rc 7 1680 that brings the pitch horizontal. Yes, it responds to those. At 1500, it looks at the center point.

Not sure why the gimbal doesn't default to that. RC<5,7,8>_TRIM is 1500.