ArduCopter 3.2 Released

ArduCopter 3.2 (aka APM:Copter) has been released as the default version replacing AC3.1.5. This is the exact same version that we invited all users to test two weeks ago.  Users who wish continue using AC3.1.5 can find it under the "Pick previous firmware" version on the MP's Install Firmware screen.

The full list of changes can be found in the ReleaseNotes but here are the highlights:
Flight Mode Enhancements:

  • PosHold flight mode: similar to Loiter but with direct response to pilot input during repositioning
  • ACRO mode handling improvement EXPO (for faster rotations)
  • Drift mode uses "throttle assist" (similar to AltHold)
  • Smoother transitions between flight modes (i..e when entering Loiter or RTL from high speeds)

Mission Enhancements/Fixes:

New Sensors/Devices:

Safety Features:

  • EKF/DCM check will switch to LAND mode if heading error > 60deg for 1 second
  • Baro glitch detection
  • Pre-arm check for Gyro calibration success
  • Pre-arm check that internal & external sensors (gyros, accels and compass) are consistent (Pixhawk only)
  • Parachute support (Pixhawk only)
  • Feedback to Pilot when taking off in AltHold, Loiter, PosHold (i.e. motors spin up a little as throttle is raised)
  • EKF (new attitude and position estimate system only used for reference in this release)

Bug Fixes:

  • Pixhawk GPS driver buffer overflow that could lead to missed GPS messages
  • Pixhawk I2C bug that could lead freeze up if I2C bus is noisy

Known issues/Warnings:

  • Pixhawk users will need to recalibrate their compasses
  • PosHold won't show up as option on FlightMode screen if you have an old version of mission planner. Please select Help > Check for Updates.
  • Landing detector is more strict meaning it may take longer to disarm after RTL, AUTO.
  • Set THR_MID parameter especially if you have a very powerful copter because "Feedback to Pilot" raises throttle to 1/2 of THR_MID
  • Spline twitches slightly as it passes a waypoint especially if WPNAV_SPEED is set > 500.
  • Dropped support for NMEA and SIRF GPS on APM boards (ran out of Flash space)
  • Dropped support for sonar for MultiCopters on APM1 and TradHeli on APM1 & APM2 (ran out of Flash space)

If you hit issues, please post them in the APM Forum and include a dataflash log file if possible.

Special thanks to Marco and the Beta Testing team from the AC3.2 beta testing thread who put their copters at risk in the pursuit of a smooth, safe release. Here are links to some of their videos: Marco's DJIs900, Holger's Water Tower, Josh's Acro, Ray's TradHeli2&FPV, Raph's Hawaii, PhillS's CommandYaw, Thor's Zombie Run&FollowMe, Phanivyas's Test, Rob's TradHeli, Christian's Test1&Test2, Balloon's Spline, JimJ's FPV, Ultrojo's ROI & Spline&FollowMe1&FollowMe2, Troy's Mission

Thanks also to the code contributors to this release including Tridge, Jonathan, Leonard, RobL, Paul Riseborough, MichaelO, Julien Dubois, David Dewey, Andrew Chapman, Emile, Allyson and many more. If you want to get involved check-out our dev wiki.

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  • The RC Pass Through function seems to now be working in 3.2.  Is this supported and production ready?

  • The 3DR export policy has changed my outlook towards Pixhawk. Having got it working nicely in a X8, a Hexa and now thanks to Ray Gamaro 's help in one of my TDR S/R helis. I find that I can no longer buy a pixhawk and ship it to Cyprus. As I only have one unit and have to keep swapping it out, I will sadly be forced to use an item from China in the future. Same applies to buying all 3DR autopilots. Nothing like living in the good old USofA and you have to feel sorry for those guys who have worked so hard. But having waited all over Xmas for my replacement 3DR radios to arrive after having had two stop working for no apparent reason, I eventually get the message that shipping was delayed due to export reasons. Export delays don't actually stop them debiting your card though. That said, 3DR do have a great after sales hot line where you can actually get help, unlike Walkera in China. I guess my next purchase will have to be from Align, who are very serious about where they are headed. Thanks for all your help in the past guys.

  • Developer


    Yes, there's some improvements which will make the transitions between flight modes smoother especially switching into RTL or Loiter from at high speeds.

    The distance sensors are used in AltHold, Loiter, PosHold (i.e. not Auto) so it should maintain an altitude above the ground.  The Sonar and range finders aren't super popular yet, maybe because the regular althold is pretty accurate but.. anyway, the feature is there.

  • Hi Randy,

    Think we will be moving up to 3.2! 3.1Code has been flying very well on our systems but do have a aggresive pitch back when flying at high speeds and switching to loiter mode. Sounds like something has been added to smooth this out? 

    Also, I see support has been added for distance sensors. Are these sensors actually being used or just giving distance information (ex. can they be used for more accurate landing altitudes)




    Bill D.

  • Thanks @Randy,
    in the previous post I have not attached the log ...
    if it can be useful.


  • Developer

    @Fabio, thanks for the videos!

  • Hi,
    I wanted to post movies inherent in great fw 3.2, the first movie is with a wind of about 20-25 km / h, and I wanted to point out the excellent stability and Alt Hold PosHold although urged by the wind.
    The second is a movie with no wind but even here you can see the great stability of the fw 3.2.
    Good work Team.



  • Got a chance to fly my aphid reptile x450 again today, still haven't performed autotune yet. but pitch and roll tuned manually seems to be quite stable :) Can't wait to go to a larger flying field to do an autotune, I hope my quad will be tuned even better :) 

  • I am tuning my TRex 450 to use APM2.6 and AC3.2. I have it performing well except loiter, which is holding well but with a few slow oscillations (about 1 every second), and some mild toilet bowling that dampens out after several seconds. I have adjusted the external compass to point to magnetic north according to an accurate handheld compass. Question is: how does the magnetic declination (MD) get applied to the compass heading used in the APM? Is it just a direct subtraction to get true north? I want the GPS north heading while moving to match the true heading via external compass + MD adjustment.
  • Another test flight with AC3.2 on my aphid x450 quad. It was quite stable despite that I did not perform an autotune yet. I tested my quad on a windy day, with intermittent gusts as before. It was able to do well while on stabilize mode. I then switched to position hold to capture video with the gopro attached below the quad. Almost everything was perfect while on position hold until one of the props was detached...when another gust of wind hit the quad head on..I found that the prop adapter slipped off...The quad fell like a rock. A bit disastrous incident since one of the motor shaft broke, again. :) Surprisingly, all of the carbon fiber props were fine. I already made repairs on my quad. I ordered another set of X2212 980KV motors but this time, the ones with threaded shafts. I am a bit paranoid now with prop adapters on non-threaded shafts.. I still flew my quad today with the same setup, but with every landing, I make sure the prop adapters are tight.. Nonetheless, I enjoyed using AC3.2 on my quad, :) Thanks to all developers.

    I will test althold on my next flight, on my previous flights, I observed that my quad dips when flying straight with althold. I will confirm on my next flights if the decrease in altitude on althold mode is significant or not. :)

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