PX4 Community Q&A: November 22, 2023

rroche · November 15, 2023, 6:01pm

November 22, 2023

Join us

Agenda

Community Announcement
Community Q&A
General Discussions

Community Announcement

A.1 :

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

Q.1 : Multirotor hold having altitude oscillations when without Laser Range Finder - Alex

When Laser Range Finder (LRF) was not working, there were oscillations happening and altitude was not being kept.

Possible issue:

GPS data was not healthy
MPC Alt Mode was set to terrain hold, so maybe it goes to undefined state without LRF

Action Item: Will share log later (apparently flight review says it is corrupted and can’t open, but can open via PlotJuggler)

Q.2: Slow velocity horizontal behavior for multirotor not consistent after v1.13 - Sverre

Issue may not be fixed in v1.14, and on main it should be fixed - Matthias

Relation to currently open PR:

github.com/PX4/PX4-Autopilot

Slow Position Mode

PX4:main ← PX4:slow-mode

opened 05:55PM - 19 Sep 23 UTC

MaEtUgR

+551 -36

### Solved Problem @marcinolokk and I implemented a slow version of the Positio…n mode. It allows to fly like in Position mode but with slower horizontal and vertical velocity plus yaw turn rate. The sources for how much slower it goes in these dimensions can be: - Parameters for metric limits as defaults - Mappable auxiliary remote inputs e.g. knobs that allow scaling down - uORB/MAVLink message specifying metric limits Fixes #19799 (note that the default horizontal speed is 3m/s which should fulfill the requirement) ### Solution - Add interfaces in the existing flight task components that are in use for Position mode to slow down - Add a new mode "Position Slow" - Add a new message for velocity limits which is supposed to be filled with the contents of the MAVLink message from https://github.com/mavlink/mavlink/pull/2015 - Implement a new `FlightTaskManualAccelerationSlow` that orchestrates the inputs ### Changelog Entry For release notes: ``` Feature: Add new multicopter slowed-down Position mode Documentation: Missing so far. It needs a new mode page best situated under the Position mode. ``` ### Test coverage The full solution was tested in simulation and on a real quadrotor with different settings and all the different inputs and combinations. It will soon be rolled out to production. ### Context - I realized in https://github.com/PX4/PX4-Autopilot/pull/22084 that there are probably conflicts with https://github.com/PX4/PX4-Autopilot/pull/20707 I'm happy to rebase and resolve. - With https://github.com/mavlink/mavlink/pull/2031 we can also bring in auxiliary remote inputs through MAVLink. I'm adding support for this separately from this pr.

Q.3:

github.com/PX4/PX4-Autopilot

drivers: Accept entire distance sensor signal strength range

PX4:main ← scoutdi:accept-entire-distance-sensor-signal-strength

opened 12:38PM - 14 Nov 23 UTC

sverrevr

+22 -5

### Solved Problem The reason for this commit is that we had a flight where t…he distance sensor was in practice disabled for large parts of the flight as the signal strength being read from the sensor was lower than 70/255 which is today's threshold. Looking at the sensor data itself we see that there were a lot of measurements with good quality that should not have been discarded. See for example this section here where all data is discarded for more than 20 seconds even thought the sensor data is perfect ![image](https://github.com/PX4/PX4-Autopilot/assets/9085288/ceabab41-dde5-46db-aed5-78648e0f2616) To explore where the limit should be, we set the minimal signal strength to 0 so that the signal strength is directly mapped to `distance_sensor/signal_quality` What we saw from our experiments were that we only had outlier measurements where the signal strength was 0. Any non zero values corresponded to a good measurement. See comments below for plots Looking at the datasheet we have the following documentation: https://static.garmin.com/pumac/LIDAR-Lite_v3HP_Instructions_EN.pdf ![image](https://github.com/PX4/PX4-Autopilot/assets/9085288/4b2d8cb7-402a-474c-b395-3879f9f12d95) So signal strength is already capped with a lower threshold calculated based on the noise floor. From this its not unreasonable that all non-zero measurements are likely good. Furthermore, at least for the terrain estimator, its not a problem if outliers are not removed at this step, as there already is outlier detection there. Is this also the case if the distance sensor is used directly in the EKF? ### Changelog Entry For release notes: ``` Accept entire distance sensor signal strength New parameter: None Documentation: ``` ### Test coverage Flying again in the same location where the problem was first observed yielded good result where the distance sensor was used and no bad measurements were accepted. ### Context Related links, screenshot before/after, video

Signal strength reporting sensor data

Q.4: Custom board, but filesystem not working properly - Sangam Thampa

Daniel: Should check ‘defconfig’ file to chance the custom board dir value, like below

github.com

PX4/PX4-Autopilot/blob/1cf38e9d762c92f7624ee8b2e0a3b40cbfa0477e/boards/px4/fmu-v4/nuttx-config/nsh/defconfig#L55


      
          # CONFIG_NSH_DISABLE_SLEEP is not set
          # CONFIG_NSH_DISABLE_SOURCE is not set
          # CONFIG_NSH_DISABLE_TEST is not set
          # CONFIG_NSH_DISABLE_TIME is not set
          # CONFIG_NSH_DISABLE_UMOUNT is not set
          # CONFIG_NSH_DISABLE_UNSET is not set
          # CONFIG_NSH_DISABLE_USLEEP is not set
          # CONFIG_STM32_CCMEXCLUDE is not set
          CONFIG_ARCH="arm"
          CONFIG_ARCH_BOARD_CUSTOM=y
          CONFIG_ARCH_BOARD_CUSTOM_DIR="../../../../boards/px4/fmu-v4/nuttx-config"
          CONFIG_ARCH_BOARD_CUSTOM_DIR_RELPATH=y
          CONFIG_ARCH_BOARD_CUSTOM_NAME="px4"
          CONFIG_ARCH_CHIP="stm32"
          CONFIG_ARCH_CHIP_STM32=y
          CONFIG_ARCH_CHIP_STM32F427V=y
          CONFIG_ARCH_INTERRUPTSTACK=768
          CONFIG_ARCH_STACKDUMP=y
          CONFIG_ARMV7M_MEMCPY=y
          CONFIG_ARMV7M_USEBASEPRI=y
          CONFIG_ARM_MPU_EARLY_RESET=y

Q.5: SPI-only driver programming issue - Janardhan

Remove all I2C stuff, then failure shouldn’t happen
Also remove I2C stuff from the CMakeLists

The config pointer:

When I2C stuff is removed, results in error regarding I2C. So need to also remove that part as well.

Q.6: Docker container in Windows issue - Janardhan

Windows crashes when running the container.

Try WSL2 instead.

Q.7: Custom naming of USART ports - Janardhan

Use case: Want to change e.g. USART 1,2,3 into 0,1,2.

Currnetly NuttX configures so that USART ports get numbered automatically
Should be way to change NuttX config to change how serial numbering works out

Could be helpful:

General Discussions

D.1 :

sverrevr · November 22, 2023, 4:14pm

We have a large slow drone where we use a max velocity of 1m/s. After 1.13 we had to re-introduce smooth position control for the drone to work well at 1m/s. Are there any plans on making px4 compatible with slow drones?