PX4 Dev Call: June 29, 2022

rroche · June 22, 2022, 5:01pm

June 29, 2022

Join us

Agenda

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

Community Announcement

PX4 master branch naming → ‘main’

In case you want to learn more: visit Github’s Post on it

Community Q&A (No deep technical discussions)

Guideline for asking a Question

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

Q.1 : Where are parameters saved in Flight controller (physically)? - Vatsal

Problem now : Not sure if saving parameter in Flash is possible.
Answer : In STM32, there’s flash backend.
Also can utilize MTD / NuttX to store the parameters
Usually in FRAM, after v1.12, it would also save into a SD card

Q.2 : Is Px4 using ROS? - Kevin

MAVROS exists as a bridge between Px4 and ROS
MAVLink is used for telemetry & controlling PX4 vehicle
MAVROS is bridging that MAVLink connection as a ‘ROS Node’
There exists uORB messaging system that acts like ROS system!
Check out the tutorial blog post on uORB → PX4 uORB Explained: Part 1 - PX4 Autopilot

Project Updates

P.1 : PWM Disarmed value PR

github.com/PX4/PX4-Autopilot

PWM: Use disarmed value as default failsafe value

PX4:main ← PX4:failsafe-defaults-disarmed

opened 07:24AM - 25 Jun 22 UTC

MaEtUgR

+84 -82

## Describe problem solved by this pull request Before https://github.com/PX4/P…X4-Autopilot/pull/19805 failsafe values stayed 0 which resulted in PWM signal being lost completely upon vehicle termination if not configured explicitly different per channel. The pr introduced default failsafe values of 900 for channels configured as ESCs and 1500 for servos. While this solved most cases there remain some unsafe ones where the output is not correctly masked as ESC, mistaken for a servo and even though the disarmed value is 0 or even set to 900 and the motor not turning when disarmed it can spool up upon vehicle termination. Also, it could be that an ESCs and servos are calibrated/set up for a different idle values than 900 and 1500 in which case the failsafe value is out of sync with the disarmed one and has to be set separately. E.g. @RomanBapst reported a VTOL pusher which was presumably not masked as ESC spinning up after vehicle termination. ## Describe your solution **My suggestion to prevent these cases is to use the channel's disarmed value as the default failsafe value.** The user has to then only change it in case he wants to have a specific PWM value other than the disarmed one for a channel upon termination e.g. to set up a PWM parachute or bring a PWM gimbal into its safest position. ## Describe possible alternatives I know this only applies to the legacy mixing system and probably mostly benefits the 1.13 release. I'll follow up with @bkueng about the new dynamic one. **EDIT:** I'll still check in but according to this the new mixing already follows this logic: https://github.com/PX4/PX4-Autopilot/blob/55563eba49f87624d7b73356ea3d421fee7ec081/Tools/module_config/generate_params.py#L281 ## Test data / coverage I did not test these code changes yet. I first want to get feedback on the proposed changes. ## Additional context IO mixing to FMU: https://github.com/PX4/PX4-Autopilot/pull/16444 Default PWM configuration loading: https://github.com/PX4/PX4-Autopilot/pull/17833 Fix for failsafe defaults being 0: https://github.com/PX4/PX4-Autopilot/pull/19805

Had a case where Motor was wrongly configured as a Servo, and having it go to 1500 PWM value fired up the motor!
Related PR on Failsafe: PWM set all failsafe values by Igor-Misic · Pull Request #19805 · PX4/PX4-Autopilot · GitHub

First, Mixer done on IO side kinda worked
Next, mixer being done in FMU now

Need to review exceptions like Parachute, in terms of configurable failsafe value

P.2 : Generic Button/Switch support support for old QGC

Need to keep Parameters as depreciated, and then fade it out
MAVLink also has implementation to make sure QGC doesn’t get confused due to missing parameters: PX4-Autopilot/src/modules/mavlink/mavlink_parameters.cpp at main · PX4/PX4-Autopilot · GitHub

P.3 : Board information metadata JSON file PR

https://github.com/PX4/PX4-Autopilot/pull/19848

Switch from Jenkins to Github Actions
PX4-Autopilot/.ci/Jenkinsfile-compile at main · PX4/PX4-Autopilot · GitHub
There are some issues on QGC Windows with Orange? board / etc.
TODO : Try out any NON-PX4 boards: Cube, etc. Weird Driver issue
Matthias using KAKUH7 with no issues on Windows
Let’s give a test with the QGC build on Mac/Linux/Windows platform and make sure the JSON fetching part works!

General Discussions

D.1 : manual_control_setpoint message roll/pitch/yaw … x/y/z naming

Discussion is here

Proposing renaming the fields as roll/pitch/yaw/throttle
What about Rovers?
- We don’t have unified control mode for Rovers (some people use Yaw, some Roll, etc)
What about Throttle range?

D.2 : Getting Follow Me into V1.13

PR is up, just needs a quick review

D.3 : Coding Format

CLang format
CLang tidy : Takes a long time to build (Currently done in Github Actions!)
Clang Tidy · Workflow runs · PX4/PX4-Autopilot · GitHub
File Names: Google C++ Style Guide

Topic		Replies	Views
PX4 Dev Call: June 15, 2022 PX4 Autopilot	0	665	June 8, 2022
PX4 Dev Call: May 25, 2022 PX4 Autopilot	0	649	May 18, 2022
PX4 Dev Call: July 20, 2022 PX4 Autopilot	0	919	July 13, 2022
PX4 Dev Call: August 10, 2022 PX4 Autopilot	1	697	August 10, 2022
PX4 Dev Call: May 18, 2022 PX4 Autopilot	0	687	May 11, 2022