PX4 Community Q&A: May 03, 2023==

May 03, 2023

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  • Community Announcement
  • Community Q&A
  • General Discussions

:loudspeaker: Community Announcement

A.1 :

: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.

Q.1: Offboard swarm control


Q.2: PX4 Dev Summit 2023 CFP Deadline :calendar:

Find the details here:

  • CFP Closes: Sunday, July 9, at 11:59 PM PDT
  • CFP Notifications: Monday, August 14

Q.3: Multirotor control equation

:thinking: General Discussions

D.1 : DroneCAN 15 Servos support

  • DroneCAN supports 20 servos (DSDL array length limited)
  • We could probably go to 16 servos support, just need to take care of FLASH overflow

D.2: RC Driver discussion

Further discussion on the splitting the RC drivers PR: [WIP] split drivers/rc_input per protocol by dagar · Pull Request #20829 · PX4/PX4-Autopilot · GitHub

We need to have a context on which protocol is used, to remove hard-coded logic!

D.3: DDS Documentation

Ramon will run the XRCE-DDS again, and then will merge the docs PR: [dds] DDS documentation & User workflow testing · Issue #21383 · PX4/PX4-Autopilot · GitHub

D.4: Release candidate for v1.14

Release candidate before next week. We will continue to compile the high level release notes.

Remaining 2 release blockers will be resolved with small fixes. Regarding 100% thrust issue, it is likely not happening with 1.14, we should keep that in mind.

D.5: Multi EKF sensor priority

Multi EKF is currently enabled for most targets. The improvement PR would add logic in EKF selection to prioritize external magnetometers.

Wnated to follow up and see if there is an update on the support for swarm flight and simulation with PX4. Looking tor a way to have offboard control functioning with PX4 for multi vehicle flight. This would allow the implementation of swarm logic. I believe this would be of interested to many researchers as well. I couldn’t find any guide online that worked for me.
Would love to learn if:

  1. This is currently supported on the main branch
  2. How that can be configured and if there is documentation in place.
  3. If this is not in place, what would it take? If someone can take the lead, I am happy to help with the implantation.
  4. If any of the community members have working examples of using swarm algorithms with PX4.


Hi @princealy , I’ll not be able to attend tomorrow, so here is the answer for your questions.
You can simulate multiple drones with PX4 and apply offboard control on them. Everything is in the docs and it refers to the current main branch:

  1. Multiple drone simulations: I am most familiar with Gazebo Classic (default gazebo version up to Ubuntu 20.04) and Gazebo Garden (default Gazebo version from Ubuntu 22.04). In both cases you can spawn multiple drone in different location and have them connected to a PX4 instance.

  2. Offboard control: Once you have the simulation running you can either use offboard through mavlink (mavsdk, mavros, the one that you prefer) or you can use the new PX4 - ROS 2 bridge and its support for multi-vehicle simulations and have all the UORB topics that you want available as ROS 2 topics. Then you can implement any swarm logic on your companion computer / offboard computer.

To be clear, PX4 does not implement any swarm control algorithm. However you can send offboard commands and implements your controllers offboard.

Does this suit your needs? Feel free to open a specific topic if you have other specific needs.

Other relevant resources: