Additional VRX 2023 Tutorials

[M1chaelM]

• [x] Create tutorials on WAMV Compliance for VRX 2023 and put these with competition tutorials @M1chaelM
• [x] Sequence for practice worlds for 2023
• [x] Sequence for competition overview
• [x] Update Thruster Articulation tutorial @j-herman
• [x] Update Visualization with Rviz tutorial @j-herman
• [x] Add system requirements to the Getting Started sequence, reference it in the installation tutorial, and update the main tutorials page to include it in the sequence menu. @M1chaelM

[M1chaelM]

@j-herman Can you look at these two tutorials:

• [x] Update Thruster Articulation tutorial
• [x] Update Visualization with Rviz tutorial

[j-herman]

@M1chaelM My plan for these and future tutorials is to assume the code is correct, and write the tutorial to match the code. I'll leave notes here when there's a significant change, in case it was not intended. Example: we used to have tags to edit in the xacro to enable/ disable thruster articulation, change the max angle, change topics... none of those parameters still exist, so I am removing that section from the 2023 tutorial. Also, we state that thruster angle control is via a "pre-tuned PID controller" - we are actually just using the default PID values for a position controller in Gazebo. Should we do some tuning? Do we want to allow the teams to mess with that? It would be set in wamv_gazebo_thruster_config.xacro. For now I will comment out the note on PID altogether.

[M1chaelM]

Example: we used to have tags to edit in the xacro to enable/ disable thruster articulation, change the max angle, change topics... none of those parameters still exist, so I am removing that section from the 2023 tutorial.

Seems ok, but let's check with @caguero about what is still supported. I think he worked on this.

Also, we state that thruster angle control is via a "pre-tuned PID controller" - we are actually just using the default PID values for a position controller in Gazebo. Should we do some tuning? Do we want to allow the teams to mess with that? It would be set in wamv_gazebo_thruster_config.xacro. For now I will comment out the note on PID altogether.

Do the default values give reasonable behavior? I don't think the teams need to adjust this but again I will defer to @caguero

[j-herman]

Also, we state that thruster angle control is via a "pre-tuned PID controller" - we are actually just using the default PID values for a position controller in Gazebo. Should we do some tuning? Do we want to allow the teams to mess with that? It would be set in wamv_gazebo_thruster_config.xacro. For now I will comment out the note on PID altogether.

Do the default values give reasonable behavior? I don't think the teams need to adjust this but again I will defer to @caguero

Actually, after further research it looks like we aren't using the PID at all. There is an option in the JointPositionController that we have enabled:

<use_velocity_commands> Bypasses the PID and creates a perfect /// position. The maximum speed on the joint can be set using the <cmd_max> /// tag.

This seems fine as long as this isn't an area where we are trying to maximize realism for the teams. I think we are focusing more on the perception and algorithms, rather than on the control details, and so a very fast and accurate repositioning of the thruster might be ok. If we want to use the PID, I'd recommend against the defaults, as they produce undesirable behavior. Good starter values might be:

<p_gain>10</p_gain>
<i_gain>1</i_gain>
<d_gain>2</d_gain> 

[M1chaelM]

This seems fine as long as this isn't an area where we are trying to maximize realism for the teams. I think we are focusing more on the perception and algorithms, rather than on the control details, and so a very fast and accurate repositioning of the thruster might be ok.

Yes, this is right--I think bypassing the PID is our way of simulating a PID that has been pre-tuned as well as possible. I think we can keep this as-is.

[caguero]

I think we're good removing the parameters that we don't have anymore. And about the angular movement of the thruster, as Jessica said we bypass the internal PID to avoid gain tunning and simplify configuration.

[j-herman]

Will need to merge PR 664 for the RViz tutorial. It's in a working state but not yet complete.

[j-herman]

This is tutorial-related, but too much of a nit to open a new issues, so I'll pose the question here: I've been doing many fresh installs of Gazebo/ROS2/VRX and keep forgetting to write down all of the additional packages that need to be installed beyond the humble desktop full install (xacro, for instance, is the first one that pops up). There was a question on the discord page that looked like the same issue. So, I think we need to add something to the installation tutorial to account for these extra packages for those who are installing directly on their systems rather than using docker. rosdep is an option; a list of other packages is another option. Which would we prefer? rosdep has been working for me to fix all the errors at once, but I know there are some reasons we might not want to recommend that.

[M1chaelM]

@j-herman I'm slightly worried by the phrase "all of the additional packages." The only one I've seen so far is xacro. We can definitely add that to the tutorial. Can you let me know if you encounter anything else?

[j-herman]

I can't remember - just know I had a sequence of two or three the first time, which wasn't a 100% fresh install. Agreed, let's just add xacro and I will recheck next time I reset a system.

[youxu2017]

The tutorial of the Rviz is not working right now ( July 12), right?

[j-herman]

The tutorial of the Rviz is not working right now ( July 12), right?

That's correct. There are some code changes required to support this and they're still in review.

[M1chaelM]

Compliance tutorials todo list:

• [x] Create the tutorial page.
• [x] Update the phase 2 and phase 3 tutorials to link to the new components and thruster config tutorials.
• [x] Update both tutorials above to also add a bullet under the submission format section that links to the new compliance tutorial.
• [x] Add the new compliance tutorial to the How to Participate Sequence, between phase 3 and validation.
• [x] Update the main tutorials page to add a line for the compliance tutorial in the details of the How to Participate sequence.

[j-herman]

The tutorial of the Rviz is not working right now ( July 12), right?

@youxu2017 The files are now incorporated so this tutorial should be working.

[caguero]

Done