PX4 Community Q&A: November 15, 2023

November 15, 2023

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  • Community Announcement
  • Community Q&A
  • General Discussions

Community Announcement

:tada: External Flight Modes is now part of main

:tada: Pixhawk FMUv6XRT is also now in tree

:people_holding_hands: Community Q&A (No deep technical discussions)

:exclamation: Guideline for asking a Question

  1. Specify what you are trying to achieve
  2. Specify what environment / platform you are using
  3. Prepare a Link or Document to help understand if possible
  4. First, ask the question on Discord or create a Github Issue!
  5. If you take over 5 minutes for the question, please continue in Discord or a Github Issue.

Q1: Why is my external module failing

A1: We should implement a CICD pipeline to make sure that external modules are not broken in the future.
Modules should talk to each other through pub/sub not build off of each other. If you hit a particular problem with mavlink receiver you can lower the priority of the mavlink receiver thread. That would be a straightforward change. Or, you could do round robin scheduling with a time slice in place so that other mavlink instances have a chance to run.

Q2: tools or tips for creating a vehicle in Gazebo

A2: gazebo sim app there is a ton of models: https://app.gazebosim.org/fuel/models, you can take one of those and start to modify it from there. Here is also a really good video tutorial: https://app.gazebosim.org/fuel/models.

Q3: Auto-land for fixed wing

A3: The auto-land for 1.14 stable is broken for terrain follow. It keeps girating up and down. Terrain follow goes from valid to invalid from valid to invalid. It can be recreated in sitl.

Q4: Collision prevention cp_guide_angle does not seem to be working to yaw the vehicle before hitting an object. How can we fix it / should we rip out the logic and add something new

A4: biggest obstacle was that there is nothing in sitl that we can test with nor something easy in real life. Andrew has a branch of this working in sitl. we can utilize that branch for people to work on the collision prevention guide angle logic behind the scenes, and then test on the starling.

Hi everybody, another question for you guys.

I have an out-of-tree module and would like to include the mavlink_receiver.h header into that said module to share a variable.

But when I follow the documentation: External Modules (Out-of-Tree) | PX4 User Guide (main) for including the platforms_common I get this error:

Even though I’m not sure if that’s the platforms__common dependency that I want, when I’m reading the definition of the px4_add_module CMake function, I think that’s how I should use it, although I’m not too sure, here’s the link that talks about DEPENDS: https://github.com/PX4/PX4-Autopilot/blob/00568985c0dd750d00eaaa53f05733e8f79714f0/cmake/px4_add_module.cmake#L66

Here’s the definition of our out of tree module CMakeLists.txt file:

And here I’d like it to be able to simply add in my file:

#include <mavlink/mavlink_receiver.h>

And use a value set there.

I hope this is clear enough don’t hesitate to ask for clarification :slight_smile:.

Thank everybody!


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