Copter-3.3 beta testing

Warning #1: an issue has been found with Tower's Pause button which can cause the vehicle to fly to an old position if the vehicle has not sent a position update to Tower in some time.

Warning #2: Copter-3.3.2 fixes a bug found in Copter-3.3.1's desired climb rate initialisation which could lead to a sudden momentary drop when switching from Stabilize or Acro to AltHold, Loiter or PosHold.

Warning #3: Copter-3.3.2 fixes an issue found in Copter-3.3.1 which could lead to hard landings in RTL or AUTO if the WPNAV_SPEED_DN was set too high (i.e. >400 or 4m/s) and/or the WPNAV_ACCEL_Z was set too low (i.e. <100 or 1m/s/s).

Warning #4: a bug was found in Copter-3.3 which could cause a sudden crash if you abort a Take-off initiated from a ground station.  Video description is here.  The bug is fixed in Copter-3.3.1 so we recommend upgrading.

Note #1: AC3.3-rc8 corrected a long standing bug in the HDOP reporting.  HDOP values will appear about 40% lower than previously but this does not actually mean the GPS position is better than before.
Note #2: if upgrading from AC3.2.1 the vehicle's accelerometer calibration needs to be done again.
Note #3: set SERIAL2_PROTOCOL to "3" and reboot the board to enable FrSky telemetry like in previous versions.
Note #4: the wiki will be updated over the next few weeks to explain how to use the new features

Copter-3.3.1 is available through the mission planner.  The full list of changes vs AC3.2.1 can be see in the ReleaseNotes and below are the most recent changes since AC3.3.

Sadly this version (and all future versions) will not run on the APM2.x boards due to CPU speed, flash and RAM restrictions.

Changes from 3.3:

1) Bug fix to prevent potential crash if Follow-Me is used after an aborted takeoff

2) compiler upgraded to 4.9.3 (runs slightly faster than 4.7.2 which was used previously)

Changes from 3.3-rc11:

1) EKF recovers from pre-arm "Compass variance" failure if compasses are consistent

Changes from 3.3-rc10:

1) PreArm "Need 3D Fix" message replaced with detailed reason from EKF

Changes from 3.3-rc9
1) EKF improvements:
    a) simpler optical flow takeoff check
2) Bug Fixes/Minor enhancements:
    a) fix INS3_USE parameter eeprom location
    b) fix SToRM32 serial protocol driver to work with recent versions
    c) increase motor pwm->thrust conversion (aka MOT_THST_EXPO) to 0.65 (was 0.50)
    d) Firmware version sent to GCS in AUTOPILOT_VERSION message
3) Safety:
    a) pre-arm check of compass variance if arming in Loiter, PosHold, Guided
    b) always check GPS before arming in Loiter (previously could be disabled if ARMING_CHECK=0)
    c) sanity check locations received from GCS for follow-me, do-set-home, do-set-ROI
    d) fix optical flow failsafe (was not always triggering LAND when optical flow failed)
    e) failsafe RTL vs LAND decision based on hardcoded 5m from home check (previously used WPNAV_RADIUS parameter)

Thanks for your testing!

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      • Thank's for the video Gervais, I think's that my problem is still there too so I'm waiting for another dampening system too, new graphs looks amazing to evaluate; I'm anxious to give a try.

    • +1,  same history with my older cuad, waiting a Pix this week if solve the problem, only esc are going to be old (I didn't ask for replace ones :( ) I follow your issue (I build another cuad that flies nice), yes, very frustrating.

  • Now that 3.3 is about wrapped up, and auto tune now does the Y axis.

    Might I suggest adding the Z axis to the auto tune goodness for 3.4?

    Every copter is a little different high powered, under powered, heavy and light. A one setting fits all approach rarely does.

    There are a handful of parameters that affect Z axis tuning, it would be a nice having them optimize themselves through an auto tune process.

    Thank you again to the Delelopers who have taken arducopter has far it has already come.

    Really, thank you.
    • Developer


      Yes, I think Leonard wants to add the Z-axis autotune to AC3.4.  We're also going to improve the user interface for autotune so the GCS can tell the user what's going on.

      • Wow, Arducopter is getting better every day!
  • Moderator

    If I recall correctly WPNAV_UP and _DN used to control the climb rate in althold, this no longer seems to be the case in v3.3, what controls it now?

    • Hi Graham,

      I think that the climb rate in AltHold (or any other mode when the Pilot controls atlitude such as PosHOLD, Loiter etc.) is controlled by:

      • PILOT_VELZ_MAX controls maximum vertical velocity in cm/s and
      • PILOT_ACCEL_Z controls vertical acceleration in c/s/s
      • ALTITUDE_HOLD_P  will determine how aggressively ALTHOLD modes will try to maintain the current Altitude.

      The WPNAV_UP/_DN params are the climb rates that the controller will attempt to achieve when chaning altitude on its own.  (i.e. You are not manually applying throttle to climb or descend. For Example, during a mission or when changing ALT in GUIDED or during RTL)

      CHeck the wiki for detailed info: Altitude Hold Mode

  • Hi Greg,

    Sorry about your crash....

    I had problems with Qbrain in other platforms (32 bit boards.)

    I spent one month to understand the problem….really hard….…. After more than 20 crashes, I simulated the problem on the ground …. With physical support one axis platform

    And the problem occurs without “loops” too…. With fast commands

    So.... maybe is a similar problem.... “frequency”… I don’t know…

    and with old APMs boards no problems....

    Video with Q Brain (look the video description) 1 year ago….

    Video afters change Q Brain

  • Looking at the Alt hold performance on a breezy day for RC10 it looks like the Alt graph line is following the DAlt better than the BarAlt. does this mean the accelerameters are out performing the Barometer under these conditions or is it an avalible trust issue making Alt look better than Baro Alt?

    What could be done to improve the alt hold in this case?


    Just for reference I will post the IMU, Vibe and RCO graphs.



    • Developer

      Hi Wes,

      DAlt is what the controllers are being told to do. Alt is the estimated altitude the controller is using and trying to make equal to DAlt. BarAlt is the raw output from the Baro before it is combined with the accelerometers.

      I believe we can do better in this area than we are currently.

This reply was deleted.


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