Alternative wave model example

[srmainwaring]

@bsb808, @caguero and @j-herman, as a follow up from our call about wave models I've created a demo using the sydney_regatta world. I forked the gazebosim branch and swapped the wave models out for the ones in asv_wave_sim.

https://user-images.githubusercontent.com/24916364/189438132-ccc66f38-fa33-42eb-8257-58629201d1d4.mov

The example uses the non-PBS shader version of the wave renderer. The ocean is a 21 x 21 grid of tiles, each 100m x 100m containing 256 x 256 cells for the FFT wave generation.

Changes

There are a few modifications:

1. The asv_wave_sim plugins build against Gazebo Garden (gz-sim7) which is the first version to have full support for macOS / Metal. It was going to be a lot of work to manage the namespace migration and retain backwards compatibility - so I opted to support Garden only.
2. The first commit on https://github.com/srmainwaring/vrx/commit/1ccfa9fcd7d20de400a6a4eb617b55e2eb11be5b deals with the upgrade to Garden.
3. The second commit https://github.com/srmainwaring/vrx/commit/e12c71fcbaad5117a45b07bbaeae6dd5ad2dcbe0 is a workaround for my installation, for some reason Gazebo will not load models downloaded by fuel.
4. The third commit https://github.com/srmainwaring/vrx/commit/3a8286af2386839dad93108f8738623391233ebe swaps the wave models over and adds the control to the GUI. There's not that much to it once the preparation has been done.

Set up and run

1. Build osrf/vrx with the above changes.
2. Follow the instructions to install asv_wave_sim. The master branch should be suitable. The GUI plugin must be manually built in ~/waves_ws/src/asv_wave_sim/gz-waves/src/gui/plugins/waves_control/build as it's not fully integrated into the top level build files.
3. Set up the environment variables. I'm using something like the following:

export GZ_SIM_RESOURCE_PATH=\
$HOME/.gz/fuel/models:\
$HOME/waves_ws/src/asv_wave_sim/gz-waves-models/models:\
$HOME/waves_ws/src/asv_wave_sim/gz-waves-models/world_models:\
$HOME/waves_ws/src/asv_wave_sim/gz-waves-models/worlds:\
$HOME/vrx_ws/install/share/vrx_ign/models:\
$HOME/vrx_ws/install/share/vrx_ign/worlds

export GZ_SIM_SYSTEM_PLUGIN_PATH=\
$HOME/waves_ws/install/lib:\
$HOME/vrx_ws/install/lib

export GZ_GUI_PLUGIN_PATH=\
$HOME/waves_ws/src/asv_wave_sim/gz-waves/src/gui/plugins/waves_control/build

Then run the world directly:

gz sim -v4 -r sydney_regatta.sdf

WAM-V

To enable the plugins for the WAM-V requires two additional changes:

• Disable setting a wavefield for the model in the spawn.launch.py: https://github.com/srmainwaring/vrx/commit/6b2d251e1671b243230c89277ef59cade39804b9.
• Replace the Surface and SimpleHydrodynamics plugins with the asv_wave_sim versions and enable the dynamics on the hull collisions only: https://github.com/srmainwaring/vrx/commit/2e2e68d3432f8ee3f779bd5af96bdaf1e29fc8f5

Run using the launch file:

ros2 launch vrx_ros competition_local.launch.py gz_args:="-v4 -r sydney_regatta.sdf"

The wave spectrum settings can be updated at runtime (mean height and direction).

https://user-images.githubusercontent.com/24916364/189539746-a3f480f7-53e0-4090-bca8-6784d87da2ac.mov

[mvanlobensels]

@srmainwaring Are you still able to control the WAM-V using the thrusters this way? The SimpleHydrodynamics also seems to compute the ship dynamics.

[srmainwaring]

Are you still able to control the WAM-V using the thrusters this way? The SimpleHydrodynamics also seems to compute the ship dynamics.

If the gz-sim thruster plugin is used, control is independent of the model for waves and the choice of hydrodynamics.

The example above uses plugins from asv_wave_sim to control the wave physics and visuals and another for the hydrodynamics. These plugins include non-linear restoring forces not captured in SimpleHydrodynamics, which uses a model that assumes small displacements from a mean position. SimpleHydrodynamics should be disabled if using the asv_wave_sim plugins.

[srmainwaring]

Closing - no further action required at this stage.