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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  • I'm using 3.1 rc2 and I must say that it is a great release but a couple of nice functions are still not working.

    FOLLOW ME (that was working great in v 2.9) is now very twitchy and copter is dangerously bouncing every time he moves toward the moving target

    ROI (DO SET ROI) (that was working fine in v 2.8) is not working anymore. Copter is facing ROI only for one WP after DO SET ROI event. Other WPs yaw is facing next WP. Tried all parameters in YAW-BEHAVIOUR (0, 1, 3) with no success. I've seen the video linked in the feature list but I can't understand how that it can be done  :)

    Has anybody tried these functions? Any hint?


    • Developer

      Hi Luciano, for ROI read the discussion here.
      About the "follow me" function i agree, with the all the version 3.x is bouncing every time, it doesn't work fine with the inertial.

      • Thanks Marco! I understand that the discussion you linked is related to Gimbal ROI. The function I refer is DO SET ROI event in mission planning that should keep the yaw of the copter toward a specific Point Of Interest. 

        I discovered just now that this is a well known problem and Randy says that it will be solved in 3.2



  • @randy, i did not find the name jonathan Challinger on APM forum.

  • Hey guys me and a few of my friends are going for a competition. Using nothing but the best, PixHawk:) Please help us share and like the video. 

  • Hello,I have a problem

    after uploading latest firmware to my APM 2.0 board with external ublox 7N GPS board I have gps blue led (3dfix)always on regardless gps connected or not

    also,gps who use to work normal does not work any more

    Can someone enlighten me what is the problem...iwe try upload previous firmware's and erasing eprom as well,uploading again 3dr gps configuration text to did not help

    I know I should ask in Forum BUT WHERE?situation over there is real mess,all the questions randomly posted under same subject (3.1) so you first need to read all the questions to see if some have your problem....80% of questions is not solved and many of them not answered..

    ....and over here only few good official people is trying to answer 1000 questions....

    • Hallo Emin

      The Eprom deleted using the Arduino software 1.0.1.
      File - Example eeprom - eeprom clear.

      Then new APM load

      • Hm,Rainer as you can see from post above I did erase command in terminal screen....also I did factory reset with reset command in terminal...

        I can arm and disarm,PPM Graupner,ppm encoder updated both on APM and RX

        I newer used arduino softwere,ist reset enough?

        • I think I know what you mean
          Start the Arduino IDE(I used 1.0.5) with your APM hooked up (and with the correct settings: comport/arduino atmega 2560). Now go to the menue files/examples/eeprom/eeprom_clear and upload that sketch. Done. uploaded arducopter 3.1.2 firmware again..same 3Dfix led is always solid on during all procedures I mentioned before

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