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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  • Leonard/Randy,

      If you get time, would you please look at these Auto Tune results for my latest quadcopter build? It's an H4 Alien 680. The props are APC 13x5.5 MR, smaller than desired, but I could not find the adapters for the 14".  It had one squirrely event during roll while AT, but other than that it went smooth.  

    Why is the Stab Pitch and Roll so diverged? The COG is darn close, and it seems to fly ok, although only flew it for a few minutes in perfectly still winds :)

    Link to flight log

  • Hello,

    I'm unable to use my tarot t2d gimbal with 3.3 on pixhawk. I have been using it connected directly to my rc on channel 6. Today, I setup the camera gimbal on mission planner to RC9 output / rc6 input according to the wiki. The gimbal initializes with the blue led steady ( no signal )  and the cam pointed to the front ( horizon ). When I press the motor switch , the blue light starts blinking and the camera turns downward, but I'm unable to control it with the RC6 switch.

    Could someone confirm that it is working with 3.3 version and perhaps point me to a soution?

    Many thanks in advance

    • I would really appreciate if someone could post a .param file of a working tarot t2d setup.


  • Hi Randy. I installed 3.3.1 RC1 today to test and issue which I have with no SBUS output on a Pixhawk controller. I´m trying to connect a Storm32 controller. If I make a direct connection between the X8R and the ST32 I get no problem, but I i try to make it through the pixhawk I get no response. I have set BRD_SBUS_OUT to 1

    • Sbus out is not implemented yet. Just make a Y harnes for your sbus. Also, it is much better to use sbus ou pin for RSSI so you have that info on your OSD. 

      • I think Robert once said that it was working. Maybe is not so difficult to implement. I would also be saffer than using a Y cable

  • Hi Randy, 

    Is there a work around for my alexmos simplebgc gimbal? I was able to use it without issues on the previous 3.3 beta build. but now it seems I cannot control the pitch. Previously, i use ch6 on my radio. The gimbal was connected to aux1 like before. MNT_Type was set to servo. but now on the latest build, i cannot use it properly..

  • Maiden flight on ac3.3, it was really stable :)
  • This afternoon another fligth but FPV now, pos hold, some less wind and no simple, all good.

    • Cala I think you are just having too much fun :D

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Aug 25