PX4 Dev Call: September 01, 2021

rroche · August 25, 2021, 5:01pm

September 01, 2021

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Agenda

Community Q&A
Roadmap
High priority queue
Release
In-Depth discussions

Community Q&A

@Roman MAVLink question: Could we extend mission items to more than 7 total parameters. Currently we have 3 parameters reserved for 3D position and 4 left for custom use. His goal is to add features to rally points like defining a minimum altitude and possible obstacles close to the specified landing point.

The design of the mission state machine is based on the reduced instruction set idea. This means it’s the idea that more complicated actions get broken down into a lot of actions/mission items. We still need to preserve the context of the higher-level action. How about adding a MAVLink message that describes the details. It could be drafted and tinkered around during development but still needs to be clearly defined for final use. It’s undesirable to cram different data/types into the 7 parameters. We have to be careful changing the entire protocol because it breaks a lot of existing implementations.

Nesting/grouping/hierarchy of the mission items could help with at least part of the problem. Here’s a pull request suggesting something like that:

github.com/mavlink/mavlink

Mission item grouping commands and messages

mavlink:master ← MatejFranceskin:pr-grouping-mission-items

opened 09:08AM - 27 Aug 21 UTC

MatejFranceskin

+22 -0

This PR adds mission items grouping commands. Groups are defined by START/STOP i…tems and 32bit unsigned integer ID. A group can be nested inside another group. When control reaches MAV_CMD_GROUP_START or MAV_CMD_GROUP_END it emits GROUP_START message with group ID and current timestamp. Task requirements and what kind of problem are we trying to solve: We want to be able to associate data acquired by the vehicle (f.e. photos) with groups of mission items. For example: user wants to inspect 2 bridges and creates a flight plan with several way points in proximity of each bridge. With the proposed solution we would group mission items in 2 groups. For each photo we will add current group id and group timestamp to image metadata. This metadata will be later used to f.e. filter out only photos taken at "bridge 2".

To prototype these MAVLink changes we should have a more simple way

Vtsal Joshi: What’s the difference between PWM output, input capture (for camera trigger timing), PWM input. He’s working on RB2040 support and doesn’t have the same functionality available compoared to an STM32.

Focus on the PWM output functionality possibly DSHOT. The input features are far less popular and useful in comparison. The output functions are used in almost every drone to interface with actuators.
Thomas Debrunner: Introducing himself working for 2 weeks now at Auterion, APX4 team. He’s diving into the code and will be in the scene contributing.

Roadmap

Discussion based on board: Roadmap · GitHub

High priority queue

Discussion based on board: High-Priority Queue · GitHub

Release

In-Depth discussions

For smaller groups expanding technical discussions, stay until the end and follow up.

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