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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  • @Josh

    I reset the bottom ESC's and now they start together. Seems that somehow brake got set to on previously. 

    The spec of the model is as follows 

    Dragonlink LRS radio

    2.4 tuned Vid. tx

    Walkera G-3s Gimbal/Sony RX100 111. Recommended.......

    Pixhawk v.3.2

    The frame is mostly balsa wood and ply. with carbon arms. The photo shows it with small high speed props and Phantom motors which gave exceptional stability but endurance was not good so it now has Multistar 390 on the top with 16x5 carbon props. and some hot phantom motors from Kopterworx with 3 bladed E-flights on the bottom. (4s was better than 3s).

    It is now a combination of fast and slow spinning motors that seem to give a good balance of endurance and response. (Fast motors on the bottom)

    The camera/gimbal system is the best I have tested and more than comparable with anything DJI for a lot less money. 3701882336?profile=original

  • @Denny,

    I too have recently started diving in to the X8 world, and its fun!  I've also built my own; technically I modified a Cinetank Mk.2 L, but its still not an RTF X8.  I'm not using the ESCs you are, rather I'm using two Castle QuadPack's (so 8 ESCs total vs two 4x units)

    One of my flying buddies is using the ESCs you are though on his bigger X8.

    Neither of our X8's start the motors at different phases - they all start together.  My initial guess on your copter is that the second ESC does not have the same ESC end-point calibration as the first one, and I suggest you make sure those are all configured for exactly the same values by performing the online calibration.  Even if you're sure you did it, it's likely wise to do it again just to be sure there wasn't an error earlier.

    After that, I also did have one motor that notoriously spun up a little later than the others, but never needed throttle bumping to get it up to speed.  I thought it was an electrical problem, but it turned out to be a bad Accel config.  Once I fixed that its been smooth flying ever since.

    I'd love to see a pic of your homebrew!  Here is mine:3701881844?profile=originalJosh

  • Well done fellas, thanks for your selfless work.

  • I have been taking 3,2 a step at a time and so far so good. I have been setting up the PIDs manually and it is now very stable. I have a home brew X8 and one strange thing that I see is that the upper motors all start nicely together in a very progressive way but the lower ones come in much later almost at the point of lift off and very abruptly, they also start in an inconsistent way. I sometimes have to add some stick input to get one started.  They are running Hobbywing quatro 25 amp. ESC's x2 and were both set up he same way. So my question is this. Should they all be starting more or less together. or is that delay a part of the normal lift off for an X8. Once airborne everything seems completely normal. 

  • Thank you to all for your tireless efforts!

  • Hi Kristoffer,

    Let me start first by saying your post is absurd.  The tuning of ArduCopter parameters allow flexibility and capability far beyond that of DJI's capabilities, especially the Naza, to say nothing of the fact it flies much better in general once configured properly.  I suggest you learn how to tune the PosHold params or perhaps just stick with DJI for now.  I hope its the first option, though.  The learning curve of any system that is full of features and capabilities is always going to be higher than ones that have less capabilities, such as the Naza.  There are massive amounts of information available in the wiki and if you learn something that you see is not in the wiki (it happens), I can tell you from experience that Randy and Craig would happily support your contributions.  First I suggest you check this link for the different params that apply to PosHold directly.  I would also look at the one for AltHold as I think this may help you get the "stickiness" of your vertical movement set up more to your liking.  If you feel PosHold isn't what you feel it should be, perhaps you could develop some enhancements yourself and submit those patches for review by the project lead (Randy)?  If not (it is a big undertaking) learn how to tune AltHold at least and go from there.  Admittedly, the ArduPilot projects need much more hands on config by the users than DJI products do, but the rewards of flight performance, capability, etc are definitely greater as your skills and knowledge improve.

    The work Randy and the rest of the devs do with ArduCopter is not as simple one may think, and the thought of "pirating" devs from DJI by 3DR (or any other flight controller) to support this project is as inflammatory as it is ridiculous.  Let's not forget that this is an open source project driven largely by the community which is quite different from that of what DJI offers.  3DR is a supporter of these projects, but not the "owner."

    I'll hop off my soap box, but hope you understand the sentiment and sincerity of my thoughts.  Best of luck tuning your copter, I look forward to hearing about your progress along the way.

  • Oh I see. I hope arducopter developers can find a way to really make arducopter fly like DJI GPS mode. The response of althold in vertical movement is too "sticky," seems like there is a deadband. Also, while on althold or moving Hybrid/PosHold, GPS positioning is inexistent unless you release the sticks which we don't actually do. Loiter, on the other hand, is too "sticky" on the position/horizontal movement. Maybe 3DR should just pirate some of DJI programmers so we can get the best of both worlds.
  • Developer


    There shouldn't be any need to reset params or re-do the AutoTune after installing AC3.2 whether you're moving from AC3.1.5 or one of the earlier release candidates.


    There's some documentation here re the EKF and DCM failsafes.  The threshold's default values are set reasonably high so I don't think you should need to adjust them.


    PosHold is just Hybrid mode but renamed to hopefully make it easier to understand it's purpose.

  • Is PosHold almost the same like DJI atti or DJI GPS mode? Or is it the same as hybrid which is just a combination of loiter and althold?
  • Ok, so I enabled EKF. What is EKF_CHECK_THRESH for and what should the setting be?


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