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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            • :((((((((((((

              Can you tell me one certain thing as One shouldn't do to prevent this bug?

              I don't have an immediate plan to upgrade anything...

              • I had to install and config all again; you have work for the weekend Alex.;)

                • You should not have to config again for this update.

                  • Alex, a disturbance such as a sync error, turbulence, sudden inputs, or anything could potentially trigger the bug. You can't avoid it by treating your sticks gently.

                  • My question was what sort of input causes this bug so I avoid it.

                    It is clearly stated at the top of the page: Simultaneous high throttle with high roll and pitch input.

                    So hopefully I will be able to avoid the above combo. I never give full deflection of stick input anyways...

                  • Perhaps something wrong when I download the firm because all de configurations failed, I installed the plane then the copter again and works well.

    • Developer

      I've posted the additional investigation of the bug on the "Loiter and RTL crashing" thread.  It's just extra details on what rate and angular errors much be achieved for the problem to show up.  There's no change in what we need to do though which is test and then release the AC3.1.3.  As mentioned above it's available now through the mission planner's Beta Firmware link.

      • Randy, I notice a strange behavior in AC3.1.3. It twitches when you switch to RTL. 

        My logs attached.

        • LMAO - I know it twitches - see here the consequence if you couple that twitch with a nasty stability bug (just fixed this past Sunday):

          Johnatan/Leonard doesn't believe me it twitches, but he will in time.

          BTW, it only twitches if current_altitude < RTL_return_altitude



          • I understand that it twitches, but innocuous navigation bugs are currently fairly irrelevant as navigation is being reworked.

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