ArduCopter 3.2 ready for wider use

After months of testing, ArduCopter 3.2 (aka APM:Copter) is ready for widespread use and we invite all users to give it a try.  In order to manage the support load at first it will be available only through the Mission Planner and APM Planner2's Beta Firmwares link.  This link is visible from the regular "Install Firmware" page if you check the "Advanced View" on the Config/Tuning >> Planner page.  On APM Planner2 the "Advanced View" it is under the File menu.

In about two weeks we plan to replace AC3.1.5 with AC3.2 as the default version dispensed by the ground stations.

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 ssupport 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 the 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 CommandYawThor's Zombie Run&FollowMePhanivyas's Test, Rob's TradHeli, Christian's Test1&Test2Balloon'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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  • Developer


    Ok, cool.  You're right that it should be the same...

  • Randy

    I saw this parameter for a week ago and checked my logs, and it was about the same value as i planned to set for THR_MID. I have quite overpowered motors(1,6kg thrustx6) so when looking at my Taranis when hovering in Stabilize mode it hovered at about 45% throttle. The value of the TRIM_THROTTLE was 472, so i tried it out and it worked.

  • Developer


    The current objectives for AC3.3 are here.  Some of the big items are making the EKF the default attitude solution which should make it more robust in cases of high vibration.  Also enabling Optical Flow is another big one.  Terrain following as well perhaps..

  • Developer


    The issue with using TRIM_THROTTLE is that it can be lower than the actual throttle required to hover because it's updated during landing at which time the throttle is quite low.

  • I've just installed AC3.2, and as soon as it stops raining, i'll try it out. By the way, the TRIM_THROTTLE parameter is it ok to use it for THR_MID, if not why?
  • Developer

    @Darrell: PosHold is just as "DJI GPS Mode", Loiter has the advantage of being able to be controlled by the "WPNAV_LOIT_SPEED" parameter (cm/sec), very useful for example when shooting video, you can better maintain a constant speed.
    For example, with full ALE / ELE command you can moves your quad at 3 meters/second if you set that parameter to 300, whatever the direction of the wind.
    In PosHold is obviously not possible, the quad tilts to the maximum angle declared in "ANGLE_MAX" parameter, then go to the maximum speed allowed for that angle, like in AltHold and Stabilize.

  • Dear Developers,

    great job! I tried today 3.2, seems to be better than previous 3.2RC versions, stable and calm in all flight modes. I just ask myself, what could be next developing direction???

  • A big thanks to the dev team and testers for all their hard work in getting this latest release ready.  Your efforts are much appreciated in evolving this market into something that we could only dream about a few years ago.

  • Thanks @Julien

  • @Todd - when you don't touch the sticks, PosHold = Loiter (same code, exactelly the same behaviour)

    The difference if when you move sticks (direct input like Alt_Hold) and when you release sticks (automatic braking  following by loiter once coptrer is fully stopped).

    Marco did some great videos to present this mode, check youtube.

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