Framework to view the buoy on RViz

[quarkytale]

Requires

• Odometry publisher: also publish Pose_V (TF) gazebosim/gz-sim#1534
• Support for universal and ball joint in sdf ros/sdformat_urdf#13
• Feature: set QoS options to override durability (#250) gazebosim/ros_gz#259

---

Tailored our SDF model and brought up upstream support for viewing the WEC on RViz.

Usage

Launch Arguments (pass arguments as '<name>:=<value>'):

'world_file':
    Gazebo world filename.sdf
    (default: 'mbari_wec.sdf')

'world_name':
    Gazebo <world name>
    (default: 'world_demo')

'rviz':
    Open RViz.
    (default: 'false')

Run with launch arguments set:

ros2 launch buoy_gazebo mbari_wec.launch.py rviz:=True world_file:=buoy_playground.sdf world_name:=playground

Note: Ignore the RViz warning [rviz2-5] Warning: Invalid frame ID "MBARI_WEC/odom" passed to canTransform argument target_frame - frame does not exist

Snapshots

buoy_on_rviz.mp4

Progress log

Breaking it down into smaller issues:

• sdformat version should be 1.7 See comment
• Sensors in the model are not supported by URDF
• Unsupported joint types: ball, universal, screw, revolute2, gearbox sdformat_urdf PR #13
• Cannot have multiple root links, all links (except one root link) should have a parent
• Publishing tfs vis ros_ign

For more details on limitations of the parser see README in the sdformat_urdf package

[chapulina]

I'm able to load the meshes prefixed by package:// on both RViz and Gazebo with this change:

diff --git a/buoy_description/hooks/buoy_description.dsv.in b/buoy_description/hooks/buoy_description.dsv.in
index 54beeea..c0ae662 100644
--- a/buoy_description/hooks/buoy_description.dsv.in
+++ b/buoy_description/hooks/buoy_description.dsv.in
@@ -1 +1 @@
-prepend-non-duplicate;IGN_GAZEBO_RESOURCE_PATH;share/@PROJECT_NAME@/models
+prepend-non-duplicate;IGN_GAZEBO_RESOURCE_PATH;share

What Gazebo does is strip everything up to :// and try prefixing the rest of the URL with all paths in the IGN_GAZEBO_RESOURCE_PATH environment variable.

For example, with that change, after sourcing my colcon workspace, I see these values for the environment variable:

$ env | grep RES
IGN_GAZEBO_RESOURCE_PATH=/home/chapulina/dev_focal/ws_fortress/install/share/buoy_gazebo/worlds:/home/chapulina/dev_focal/ws_fortress/install/share

So consider a URI like this:

https://github.com/osrf/buoy_sim/blob/ff2f498a5afda06bf0a42d4188fc3d7bf6c582b4/buoy_gazebo/worlds/test_mbari_wec_model.sdf#L22

Gazebo will try:

1. /home/chapulina/dev_focal/ws_fortress/install/share/buoy_gazebo/worlds/buoy_description/models/mbari_wec/meshes/buoy_float.stl - that doesn't exist, continue
2. /home/chapulina/dev_focal/ws_fortress/install/share/buoy_description/models/mbari_wec/meshes/buoy_float.stl - that exists!

[chapulina]

Just gave it a quick try

[chapulina]

I think we should be able to keep 1.8 once we start using Fortress in sdformat_urdf, see

• Galactic: Support Citadel, Edifice and Fortress ros/sdformat_urdf#8

[quarkytale]

Though the functionality is still incomplete (tfs aren't being published, wip on ros_ign), this should be clear now to be merged as its won't affect simulating using gazebo!

[chapulina]

Just checking, with this PR as is, the buoy doesn't show on RViz, right? We need TF for it?

Also note that there are linter errors.

[quarkytale]

Just checking, with this PR as is, the buoy doesn't show on RViz, right? We need TF for it?
No the buoy would still be visible, only it can't translate movement in rviz as seen in gazebo.

I think I found the issue with the transforms. Seems like coming from here or its ros2 equivalent https://github.com/ros/kdl_parser/blob/a1ba6dfffc9c95b30d8a099f8785db4cf5c0342f/kdl_parser/src/kdl_parser.cpp#L103. Not sure what this library does but missing universal joint support.

[chapulina]

Great work! I just have some smaller comments, and we should wait for ros/sdformat_urdf#13 to be merged before merging this one.

[quarkytale]

Support from sdformat_urdf and upstream Gazebo is all merged! This is ready for a final review.

[chapulina]

LGTM! The only things missing before merging:

• See Publish tf_static with transient_local durability #64 for handling the tf_static transform better
• We need an ign-gazebo6 release with the changes from Odometry publisher: also publish Pose_V (TF) gazebosim/gz-sim#1534, I'm working on it

[chapulina]

Works great! All necessary releases are out, this is good to go!