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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  •  A bump on my problem of 12 hrs ago.

    I see that the altitude drift after  initial  boot isn't reset on arming. Is there something new there?

    Yesterday, I took off from +3m and landed at 9m. This would affect autoland. (in this case I did a manual land.

    WHen I tested on the bench, the altitude read near 12 meters after only about 5 min. It didn't reset on ARM.

    This last test was indoors without GPS, however a similar result occurred previously outside with HDOP of 1.3

    Anybody know what's going on?

    I'm going to fly today. I'll try letting it "settle down", then reset power, its shouldn't deviate much from zero on the ground, but that's not a reasonable fix.

  • Hello @ll,

    sorry if I overread the solution to my problem but I still cant find it in any forum. I have a PX4FMU + IO and APM 3.2.1 runs fine on it. I can upload to 3.3rc4 with mission planner but then I cant connect anymore. I'm trying APM Planner2, Mission Planner and qgrountcontrol. None of them connects. Just a timeout. I also tried different speeds but it doesn't work. I can then go back to 3.2.1 and everything works fine again. Does anybody have an idea how to solve this?`I see people running 3.3rc4 on PX4 here in the forum...

    Thanks and greetings from Austria


    • Hi

         I have done autotune with v3.3 r/c4   twice now and notice that rate P and rate I are identical in roll and also in pitch,  (5 decimal places ) coincidence?, part of the algorithn ,or bug?

      any way my Y6 flies so sharp and crisp now I am very pleased Thanks all.

       Tim Painter

      • Developer

        Hi Tim,

        That is part of the algorithm.

        Glad you are happy with the results!!

        • Hi

              Yes i think auto tune is truly sorted now.   just one thing after autotune completes I land with autotune selected and as soon as the legs touch down  the tri (y6) copter does a bucking bronco act, finaly fliping before i can disarm . This has happened every time ( thank heaven for soft grass) normal flight landings are easy(stabilise)

             Any way Thanks again for working on v3.3


  • This is a bump forward from Monday. My sonar worked fine with 3.2.1 but I get an error message with 3.3 rc4...

    I set up my sonar (1240 analogue) and I get accurate readings in Mission Planer but I can't arm the quad. I get a "prearm check rangefinder" message. I have to disable it by setting RNGFND_PIN from 14 to -1 to arm the quad. Is this a bug in 3.3 or am I doing something wrong?

    • Hey Terry

      Pls do this -> "The check can be disabled by setting ARMING_CHECK to Skip Param/Sonar." U found the Parameter in the Full Parameter List.

      Greetings, pit

      • Thanks Pit, I'll give that a try but I wonder why the prearm check fails?

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