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 Thomas   ..No you do not have to redo the set up again .. Unless its a major update that requires it.

      Regards Reuben

    • i'm wondering the same thing .

      • Hi Sergos    No you do not have to redo the set up again .. Unless its a major update that requires it.

        Regards Reuben

  • hi does anyone know the changes 3.1.4 introduces ? Can't find changelog anywhere .

    • AC-3.1.4-rc1 is now the official version available through the Mission Planner.

      There are no changes for APM1 and APM2 users, but for PX4/Pixhawk users there are these bug fixes:
      1. Bug Fix for Pixhawk/PX4 NuttX I2C memory corruption when errors are found on I2C bus
      2. Fat system file corruption bug that could lead to corrupt log files

      • Hello, i have v3.1.4 in my Quadcopter's APM 2.0. i want to understand the code and for that i need to open sourcecode in arduino software, how can i do that?

  • Fellow droners, i had been testing number of quad and hexa frames using AC3.1.3. the results are fantastic, they all fly superbly stable even in stabilize mode (No loiter). of course the credit goes to a superb code of AC3.1.3. a second reason for super performances is something an individual flyer has to do himself. that is balancing the props. whatever brand it is and irrespective of being nylon/carbon, must balance the props using a good quality magnetic type of balancer. use cyno glue on tip to add weight. scrub after drying using a knife if overweight. you would be surprised to see the difference in performance after balancing the props. i discovered this after two years of flying quads.

  • I thought i read, a few weeks back, that Firmware 3.2 would be released at the end of April, is there a status update on 3.2 release?

    • Developer

      Is in the final testing phase, stay tuned.
      The small delay is related to the attempt to give out a very stable firmware.

      • I wish a smooth transition from AC3.1.4 to AC3.2.

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