APM:Plane 3.5.1 released


The ArduPilot development team is proud to announce the release of version 3.5.1 of APM:Plane. This is a minor release with primarily small changes.

The changes in this release are:

  • update uavcan to new protocol
  • always exit loiter in AUTO towards next waypoint
  • support more multicopter types in quadplane
  • added support for reverse thrust landings
  • added LAND_THR_SLEW parameter
  • added LAND_THEN_NEUTRL parameter
  • fixed reporting of armed state with safety switch
  • added optional arming check for minimum voltage
  • support motor test for quadplanes
  • added QLAND flight mode (quadplane land mode)
  • added TECS_LAND_SRC (land sink rate change)
  • use throttle slew in quadplane transition
  • added PID tuning for quadplane
  • improved text message queueing to ground stations
  • added LAND_THR_SLEW parameter
  • re-organisation of HAL_Linux bus API
  • improved NMEA parsing in GPS driver
  • changed TECS_LAND_SPDWGT default to -1
  • improved autoconfig of uBlox GPS driver
  • support a wider range of Lightware serial Lidars
  • improved non-GPS performance of EKF2
  • allow for indoor flight of quadplanes
  • improved compass fusion in EKF2
  • improved support for Pixracer board
  • improved NavIO2 support
  • added BATT_WATT_MAX parameter

The reverse thrust landing is particularly exciting as that adds a whole new range of possibilities for landing in restricted areas. Many thanks to Tom for the great work on getting this done.

The uavcan change to the new protocol has been a long time coming, and I'd like to thank Holger for both his great work on this and his patience given how long it has taken to be in a release. This adds support for automatic canbus node assignment which makes setup much easier, and also supports the latest versions of the Zubax canbus GPS.

My apologies if your favourite feature didn't make it into this release! There are a lot more changes pending but we needed to call a halt for the release eventually. This release has had a lot of flight testing and I'm confident it will be a great release.

Happy flying!

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  • Guys, is it possible that once a new FW is available the plane "doesn't want" to fly with the old version? 

  • Developer

    @Jason, I'd like to try to reproduce the problem. I strongly suspect it is related to something in your parameters.

    Can you please do this:

    1) downgrade to 3.5.0

    2) connect with MissionPlanner and save a full copy of your parameters

    3) send me the parameter file

    After you have captured the parameters, try setting the FORMAT_VERSION to 0. Then reboot. This will reset all your parameters to defaults.

    Then try loading 3.5.1 and reload all of your parameters. Please let me know if this fixes the problem. If it does then I will try to reproduce by loading your parameter file.

    Cheers, Tridge

  • I tried that as well, The strange part is I have no issues with 3.5.0, only 3.5.1. This is an original 3D Robotics pixhawk as well, not a chinese version

  • Try erasing the SD card. I have had strange things happen when the SD card gets lots of data on it. BTW a Pixhawk won’t work without a SD card.

  • I was able to get 3.5.0 back onto my planes pixhawk by flashing an old custom firmware I had then reverting to 3.5.0. 3.5.1 loads fine but then the pixhawk goes into that weird mode where it only shows a solid yellow light and is basically dead. Anyone else have issues with 3.5.1?

  • Developer

    @Stephan @Chris

    The mid point can be set to any PWM value but I've only tested it at 1500. Another tester tried it at a different value on early code and had trouble but then couldn't re-test. There's not much gain in using a number other than 1500 so I'd recommend using that. Param configuration is on the wiki

  • I tried a different pixhawk without issue. Ive been using the one that has the issue for over a year and have hundreds of flights on it. Is there a way to reset the firmware? every time I re-upload the firmware it's the same issue. After initializing it's a solid yellow light and does nothing.

  • I just uplaoded 3.5.1 onto our test plane and at first it failed. After a few tries it successfully uploaded the firmware, however, it pixhawk will boot up, flash yellow, do the calibration (Red and Blue flashing) then when it goes back to yellow it is just a solid yellow light and the external arm button is off. I can not connect to mission planner either.

    Any idea's what happened or how to fix this? I've uploaded firmware multiple times for ardupilot and arducopter and never had an issue.

    Thank you and thanks for all the hard work!

  • Thanks Tridge and all others for the new release.  I am hoping to implement the PixRacer with this release.  One issue I see right off is that the Safety switch does not seem to work like the Pixhawk did.  This may be a known PixRacer issue but I couldn't find a lot on it.  Does anyone know if this is just an isolated issue or something wider?  Also, do we foresee the wifi board for the PixRacer supported in the future?  I read in other forums that this is being worked on in Copter but just wanted to know what the support looks like for Plane.  Thanks again.

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