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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  • Just to add my thanks.  Great job on 3.2 everyone. 

    Tried Alt Hold, Stabilize, Loiter on my Iris today and it worked great.

  • Not sure this sentence below is really correct. Hovering means periodic adjustment on motors to keep the position, which means power.

    After me flying at a constant speed, like circle,  it gives you longer fly time.

    "Hovering consumes less power than flying in any direction"

  • Hovering consumes less power than flying in any direction. When I compare changes I have made to a setup , I always compare during hover with calm winds. To compare flight time while flying is not accurate since flying is dynamic. Glad to hear it is doing better.

  • @carlos

    RTL can be set to fly on the current altitude so it would not climb up before returning to launch. However, it can also be aborted by switching to other flight modes so you can get manual control. In my TH9X transmitter, I programmed an override switch so I can easily go to stabilize mode regardles of the current flight mode, it is the same as flipping the flight mode switch to other mode then flipping back to stabilize. 

    My TH9X has opentx firmware runnning on it, by the way. :)

  • @michael

    i did not know that land mode also uses GPS like the RTL. Thanks for the advice.

    Anyway, I tried to fly my apid reptile quad today, I brought my FPV Monitor to check on the satellites and other stats before flying. As soon as I got high number of satellites, I flew my quad. The condition today was not ideal, with head wind blowing intermittently causing the gust of wind to smash agains my quad in air. Luckily, my quad was able to maintain its level position after sequence of correcting its level. I was afraid when my quad almost flipped upside down due to a big gust. But everything went fine in mid air. I tried to land the quad but it was quite difficult to land correctly since the wind was quite strong even near the ground, in addition to the gust pushed by the props. So most of my landing flips as it touches the ground. But it was tolerable, no damage acquired. 

    I tested the RTL by doing a simulated radio loss, it went fine (except for the flipping again on the ground due to the wind). Lastly, I flew my quad again around 30m, and waited for the battery failsafe to trigger. After a couple of minutes, the quad signaled the land mode triggerred by batt failsafe. It did not drift away like in my other flights before. I believe this is because of the good gps signal with my flights today. Thanks Michael for clarifying that matter.


    In my last flights, batt failsafe triggers early, so I replaced my 3dr power module with another unit, good thing I had another 3dr power module, and then I calibrated the voltage. In my flights today, I noticed that my quad is flying longer before the battery failsafe kicked. Maybe the 3dr power module initiallly installed is soomehow defective. Though I cannot really pinpoint if it was really the issue.

    I compared my flight today in open field with my previous flights (actually hovering at an altititude) in my backyard. My flight today was longer. Is hovering at an altitude consumes more battery than flying in an open field? 

    thanks again to everyone who enlightened me :)

  • @Artem, good suggestion, you should still be able to controll altitude with throttle to avoid obstacles.

  • I use Land often and do not have any issue with it.  RTL and LAND both rely on GPS and other things to land so if Land does not work then RTL should be worse.

    The other day I was near my house and hit the Land switch and it started to land.  Then at about 1 meter it flew at me for some strange reason. I check the logs and everything looked good.  Low HDOP 12 Satellites.

    What I found out though was that my house slowed down the GPS signal and caused the GPS to drift to the left which caused the copter to fly right because it thought it was moving off course due to wind.

    Needless to say it crashed into the ground away from my house this time and it did it post hast as you say.


  • @Carlos, if you set RTL alt to 0 it will perform RTL at the current height. Of course this is not beneficial if flying behind obsticles. 

  • @Carlos, if you set RTL alt to 0 it will perform RTL at the current height. Of course this is not beneficial if flying behind obsticles. 

  • Set your FS voltage high enough so that you will have enough power to RTL. RTL uses a lot of power because it has to gain altitude then travel home and land. My first try was almost a disaster because I set the FS voltage too low and was some distance away fro home.

    Good luck.

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