ArduCopter-3.1 released!

After months of testing AC3.1 is finally available in the Mission Planner and GitHub.

Warning #1: If the vehicle is left landed (but armed) while in AltHold or Loiter mode for more than a few seconds, the vehicle may suddenly jump into the air the moment the pilot raises the throttle above zero.  The reason is the baro altitude may fall while the vehicle is sitting on the ground.  In AC3.2 this bug is fixed because we reset the target before take-off.

Warning #2: Motors will spin (slowly) by default as soon as the copter is armed!  You can switch this feature off by setting the MOT_SPIN_ARMED parameter to zero.

Warning #3: if you see "Bad Gyro" on the HUD then you may have a blown 3.3V regulator.  See this thread for details.

Warning #4: if you use a sonar set the SONAR_GAIN parameter to 0.8 or lower

Warning #5: Trad Heli users should now connect their main rotor ESC to APM's RC8 output

Warning #6: Trad Heli BUG causes loss of collective control in ACRO mode if swash type set to flybarred (i.e. not flybarless).  Will be fixed in AC3.2.


The major improvements over AC3.0.1 are (full list here):

1. Pixhawk support (Tridge & PX4 development team)

2. Autotune of Roll and Pitch gains (Leonard/Randy)

3. Drift mode (Jason)

4. Improved Acro (Rob/Leonard) and new Sport mode (Leonard)

5. Arming, Take-off, Land in Loiter or AltHold

6. TradHeli improvements (Rob) including:

a) support for direct drive tail rotors

b) smoother ramp-up of main rotor

c) reduced collective for better control in stabilize mode (STAB_COL_MIN, STAB_COL_MAX params)

7. Support for SingleCopter (Bill King)

8. Performance improvements resolve AltHold troubles for Hexa & Octacopters

9. Safety Improvements:

a) GPS Glitch detection (Randy)

b) Motors spin when armed (Jonathan Challinger)

c) crash detector shuts off motors if copter flipped for 2secs

d) batt failsafe option to RTL instead of LAND, gps failsafe option to trigger AltHold instead of Land

e) more pre-arm checks of inertial nav speed,

10. Bug fixes:

a) optical flow working again (although performance is still not great because not integrated with inertial navigation)

b) ROI working (use DO_SET_ROI command)


How to upgrade:
Click on the MissionPlanner's Initial Setup >> Install Firmware screen.  The version numbers should appear as "ArduCopter-3.1", then click the appropriate frame icon and it should upgrade as per usual.

Special thanks to Marco and the many beta testers on the AC3.0.1 thread who put their copters at risk during the testing of this new version and uncovered many problems so that you don't have to!  Here are some of their videos: loiter in wind, patio sonar, autotune, autotune2, roi, beach, acro, vrbrain, tricopter, train spotting, radio failsafe, the tree, double loiter


If you haven't seen it recently, please check out the ArduCopter wiki.


Feel free to post comments below and we're going to use the new APM Forum for support issues so please post your support requests there.

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  • Hi, can someone assist me with my log (not full log). I got a very bad "glitch" between 3950 and 4050. It was in RTL when it suddenly roll and pitch but recover quicly after. Landing was normal.

    Setup: APM with external compass, ublox gps, OFM seeker quad. PID was set by autotune.



    2014-05-17 16-26-03.log
  • Developer

    ArduCopter 3.1.5-rc2 should appear in the Mission Planner's Beta Firmwares area shortly.  This is our 2nd attempt at the AC3.1.5 fixes.  There was unfortunately a typo that caused loiter to act as AltHold in -rc1. Very sorry about that.

    The changes are in the ReleaseNotes.txt and below:

    ArduCopter 3.1.5-rc2 20-May-2014, Changes from 3.1.5-rc1
    1) Bug Fix to broken loiter (pixhawk only)
    2) Workaround to read from FRAM in 128byte chunks to resolve a few users boot issues (Pixhawk only)
    ArduCopter 3.1.5-rc1 14-May-2014, Changes from 3.1.4
    1) Bug Fix to ignore roll and pitch inputs to loiter controller when in radio failsafe
    2) Bug Fix to allow compassmot to work on Pixhawk

    The FRAM issue (the first #2 above) only affects a handful of users who have recently found that their boards won't boot properly.  It's been traced to some kind of issue with the FRAM storage on the Pixhawk in that it can't read chucks larger than 128bytes.

    All feedback appreciated!  Hopefully this one will be ok and will become the official release in a few days.

    • I wonder if this is why I am having issue on my Ardupilot32/Revo?

    • 3.1.5RC2 works well!

      tested Stab, Alt_h, loiter and Flip!

      Thanks dev team!

      • Hi, I wanted always to try the Flip option, but I cannot find the right reading about it first, could you give me a link with the description? Thx! 

    • Hi, just tested rc2, rock steady, loiter now working, tested drift and 5 waypoint auto, RTL.

      I am only noticing 2 little twitches when entering loiter.  Flying the hexa pixhawk.

    • Hi, rc2 works perfectly for me - loiter is back working and the radio failsafe now works on the taranis for the first time.  Hurrah!  Thanks guys, great work.

    • Now Loiter working perfect.

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