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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    • You should change STB_RLL_P and STB_PIT_P. Because this converts a angle error to a desired rate...

      What value are they now? 


      • Hi Menno,

        Here are my current settings obtained via the auto tune function.

        3702644102?profile=originalRoll and pitch rates seem quite ok.
        So as you suggested is to turn down the stab_P for roll and pitch.

        • Yes I would try that, make them 3.0 for roll and pitch... you can leave yaw as it is. The rate gains that Randy was pointing out seem too low to be causing your problem.

          I think the rate gains could even be a bit larger, but for your next text maybe leave it as it is. However I would also lower the integration gains (I for rate roll and rate pitch) from 0.085/0.08 to 0.010. Normally your quad should also fly pretty okay with I's and D's to zero if your P's are not too high...

          Does the quad respond good (good directions) to minor pitch/roll/yaw inputs? If it does, try setting the parameters as I just said ;-). Start with minor deviations, go to bigger deviations and in the end try fast deviations. (but I would avoid moving your stick instantaneously to their extreme positions...)

          Let me know how it flew ;-)

          • Menno,

            Thank you for the feedback.
            I will certainly give it a try as suggested.
            Hopefully the weather stays fine for some testing :-)


      • Hi Menno,

        I don't have the values for the moment but I'll check them out this evening and get back to you.

        Thx already for the feedback

        • Developer

          Perhaps the most important gain to get correct is the Rate Roll/Pitch P gain.  There's some discussion of this on the Tuning wiki page here.

          • Do these parameters have an effect on the stabilize behavior or are they just for pilot input?

            • They both do yes... all gains (ending with _P, _I or _D) have an effect on stability. 
              You should definitely choose these values within the adequate range. Set to the default values and tune from there using a tuning guide.

              ANGLE_MAX for example is for changing pilot input 

              • ANGLE_MAX doesn't change pilot input, ANGLE_MAX manages the max amount of lean angle on the pitch and roll axis on the copter in stabilized modes (not including Loiter).  It then maps stick input in a way where hands-off is no lean angle, and full stick deflection along that axis is what lean angle APM:Copter will try to achieve and sustain for as long as the stick is on that axis.  The amount of lean angle is then proportional to the amount of stick deflection, not including any Expo you've programmed on your transmitter.

                • yes so it's the same as changing the pilot input... ;-). Witch pilot input I mean the mapping...

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