PX4 Dev Call: August 10, 2022

August 10, 2022

Join us


  • Community Announcement
  • Community Q&A
  • Project Updates
  • General Discussions
  • Weekly Overview
  • High priority queue
  • Release

:loudspeaker: Community Announcement

: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 the Slack or create a Github Issue!
  5. If you take over 5 minutes for the question, please continue in Slack or a Github Issue.

Q.1 : How does MAVROS co-exist with DDS? - Michael

Have a custom MAVROS for ROS2, and have been using PlotJuggler for plotting live during flight.

  • With direct DDS communication, the translation of MAVLink message to ROS topic would be eliminated, which is convenient :+1:
  • DDS connection may suffer from lossy connection (e.g. Over the Air Telemetry Radio), so MAVLink communication can be better there

Q.2 : Control allocator trim - Chris

Let’s say we have 1000 ~ 2000 us range Actuator. And you need to trim it to one side. Would it then leave a ‘deadspace’ in the maximum control signal? (Or does it linearly map the input to output so that we still have full range of motion?)

  • The trim should be in the hardware level (e.g. PWM in microseconds)?
  • But that would lead to *multiple trim settings for different output protocols (CAN, PWM, etc)

Q.3 : Airspeed integration for control allocation

It is still unclear if we want to bring the airspeed consideration into control allocator, but would be nice to discuss together.

  • Shared Rate controller

Q.4 : uBlox driver

Made a change in driver to enable RTCM passing through directly to the Rover

  • Currently for Rover startup script, it disables UART2.

Currently for Underwater Robot SITL, we are not using hydropressure sensor data, and is now using barometric data.

:construction_worker_woman: Project Updates

P.1 : Transition to XRCE-DDS compatible PR coming soon

Exciting possibility of having real-time PlotJuggler plotting generic uORB data via DDS connection :+1:

Timestamp setting discussion

  • Would be better to consider it as a ‘metadata’ instead of a mandatory field user needs to fill in when publishing a uORB message.

P.2 : uORB Service Implementation

  • Where is the ROS2 implementation / metadata architecture? → RMW libraries &

P.3 : Multiple height sensor fusion - Mathieu

Would love to get feedback & test logs!

P.4 : Helicopter bringup is coming soon - Matthias

PR is coming up with all the learnings :helicopter:
Still working on a nice ramp-up (spool up) behavior.

And found a bug in Multicopter Attitude controller

:thinking: General Discussions

D.1 : Geofence Altitude limit overshoot bug

@DPatrick has a good understanding of this issue and may join the call to discuss this.

D.2 : Momentary switch activated mode/ transitions - Chris

There is a stale PR that tried to implement this:

:calendar: Weekly Overview

:mouse2: Github

Recently updated Issues / PRs in PX4-Autopilot Link

Pull Requests

:computer: Slack

:phone: Last Dev-Call

PX4 Dev Call: August 03, 2022

:exclamation: High priority queue

Discussion based on: High-Priority Queue · GitHub

:ear_of_rice: Release


Great notes, thanks for that!