PX4 Community Q&A: July 19, 2023

[rroche]

July 19, 2023

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Agenda

• Community Announcement
• Community Q&A
• General Discussions

Community Announcement

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A.1 : v1.14 Release update

Yesterday, we discussed during maintainers meeting that we are now going to release Release Candidate. So more flight testings will be helpful!

Please share with us your logs here [v1.14 Release Candidate] - Flight testing & Flight Issues (logs) · Issue #21358 · PX4/PX4-Autopilot · GitHub

A.2: CFP for PX4 Dev Summit 2023 has now ended!

PX4 Developer Summit | LF Events

Community Q&A (No deep technical discussions)

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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 : GPS failure not triggering failsafe / using secondary GPS

PX4 Community Q&A: July 19, 2023

Q.1 : Position GPS failsafe not activated We had a crash a few days ago where the drone lost all the satellites of the primary GPS (ublox F9P) and started to go off in all directions. The root cause is known: it’s the antenna screw that unscrewed and cut off satellite signal reception. My question is why, in such an obvious case of loss of position, didn’t the Position failsafe activate? We also have a secondary GPS and it was not used even though reception was good for it. Open issue here.

Prognosis: Currently there’s no implementation that switches to secondary GPS, if the primary GPS is still giving data (even if it is corrupted / unreliable).

And using that bad data getting fused for EKF2, resulted in having local position being ‘valid’, whereas it was diverging.

There is currently no switching to secondary GPS when primary GPS quality degrades, could be added. You could kind of simulate it with GPS blending, but with one GPS using RTK and the other not, it’s not ideal to use that.

Q.2: Direct GPIO control for IO processor, resulting in compilation error

Pixhawk - Enabling GPIO output

Hello, I’ve been able to control all FMU GPIO pins successfully, but I was wondering if its possible to control the GPIO pins for the IO processor (px4io). I’m using V6C hardware and I’m getting an error when I’m trying to use these pins. Here’s what I’ve done: I’ve added this definitions in boards/px4/io-v2/src/board_config.h to make it more readable: #define IO_CH1 GPIO_PWM1 #define IO_CH2 GPIO_PWM2 #define IO_CH3 GPIO_PWM3 #define IO_CH4 GPIO_PWM4 #define IO_CH5 GPIO_PWM5 #define IO_CH6 G…

Answer: Pinged on discord, and will get answers hopefully!

Q.3: XRCE-DDS client not starting in PX4 - ibrahim

In simulation it works fine, but in hardware client is not starting. Connection via USB.

Possibly related: uXRCE-DDS (PX4-ROS 2/DDS Bridge) | PX4 User Guide (main)

Perhaps having USB connection is the reason XRCE-DDS doesn’t work?

TODO: Will post Github issue on this. Perhaps there’s XRCE-DDS configuration issue.

Q.4: MAVROS communication with ROS2

You can use the bridge, and the ROS1 interface should work: GitHub - ros2/ros1_bridge: ROS 2 package that provides bidirectional communication between ROS 1 and ROS 2

General Discussions

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D.1 :

[Katawan]

Q.1 : Position GPS failsafe not activated

We had a crash a few days ago where the drone lost all the satellites of the primary GPS (ublox F9P) and started to go off in all directions. The root cause is known: it’s the antenna screw that unscrewed and cut off satellite signal reception.

My question is why, in such an obvious case of loss of position, didn’t the Position failsafe activate? We also have a secondary GPS and it was not used even though reception was good for it. Open issue here.