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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          • Are we sure this is equivalent to doing command line erase and reloading the firmware?

            The question is that changing the mentioned parameter back to "0" may stop the HUD spinning but maybe there is something still hidden after the compassmot.

            I hope some developer would confirm this. Because Bart if you are correct, then you really found a good short cut to it:)


        • Hm..I did try reload 3.1.3 again but without reset command...I guess all over again is my way...Thank you Steve

  •  Please restore back flight mode position hold for 3.2

    I am happy using pos hold for 3.1

    Important for aerial photo, manual throtle and lock position. Loiter cannot do that in fast climbing.

    • it is still there, it is just a bug in MP. You can set that flight mode in your full parameters list until the MP bug is fixed.

      • Tq Brit.

        I set value to 8 for pos hold. In full parameter.

        It works

  • Hello
    after the problems with the Compass offsets were 0 0 0 solved via the MP, now the following structure.

    Frame for all Pixhawk same.
    Software for all Pixhawks same.
    Compass was the same area where calibrated.

    1. PIXHAWK 2.4 / 5 months old. Compass offsets 53,8559 / 84,23895 / 85,17641.

    2. PIXHAWK 2.4 / 3 weeks old. compass offsets 363, ---- / 195, --- / 299, ----

    3. PIXHAWK 2.4 / 3 weeks old, compass offsets 294, --- / 185, --- 397, ----.

    How is that possible?

    was provided by the ARMING check compass disable.

    could be flown, no problems, no problems at RTL came back to the point.

    Why the different Compass offsets?

    • I have noticed that with external magnetometers that the offsets can vary from unit to unit even for those purchased in the same batch.  However, I have also found that the way you do the calibration routine changes the readings a bit too.  The readings seem lowest and generally best matched to landmarks in mission planner (google maps) when the calibration rotation is done at a uniform speed throughout the rotation of each axis.  I.e. spin it as uniformly as possible.  Herky jerk motion during calibration seems to make the offset readings higher.

      when calibration is done, I also check the offsets against actual landmarks like the street I live on.  If the vehicle heading shown in mission planner doesn't match the map within about 5 degrees, I manually change the offsets until it does.  You need to check it for variations in pitch and roll while holding the heading steady.  Heading should not move as you vary pitch and roll.  If it does, the calibration is off.

      • Hi Steve
        I agree with them to some.
        only be on 2 Pixhawks the offsets as high indicating the Board an error. a person who does not know about this thing has is overtaxed.
        such high offsets are not calibrated by inappropriate to reach.
        Also, it is not normal in the MP 99 of the compass is always zero, and the offset 0 0 to 0.
        the MP software needs to be changed.

  • Hello!

    I have several problems with my hexa with 3.1.2 firm.

    I attached the log.

    The installation seems fine...

    Anybody could help me?

    2014-04-15 15-42-54.log

  • Has anybody successfully removed "yaw wagging" from their quads? I'm flying a Discovery Pro with a Pixhawk and external GPS+Mag on a post. When I review my video footage, there is, in all modes (some more than others), a very noticeable slow yawing that is not periodic, more random than not. Coming from the CC3D (accels and gyros only) and using Axis Lock for yaw, I don't remember this occuring.

    Besides doing calibration, compassmot, and reducing Stab_Yaw_P, is there any better way to ask the aircraft to not yaw when not commanded, and worry less about "staying" on a magnetic heading, and instead just resist change via gyros+accels? I'm concerned that small changes in mag heading are asking for the "corrections" instead of just using old school IMU sensors. This wagging is just killing so many otherwise great video shots -- I've gotta fix it!

    Any thoughts or advice would be greatly appreciated!

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