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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      • Developer


        Thanks for testing and for figuring out the Fence issue.  I'm pretty sure you're right.

        The low HDOP value is because of the "Note #1" mentioned in the main part of the discussion above.  It's a bug fix to the value pulled from the Ublox (previously it was actually "PDOP").

        The "Need 3D Fix" message is clearly a message we need to clarify because someone asked this same question about 2 days ago.  The EKF has a bunch of other tests it does including checking the GPS velocity but we always display the same failure message regardless of which of those checks have failed.  In short, what you're seeing is the EKF isn't yet happy with the info coming out of the GPS.

        • Hi Randy,

          Have we got any closer to what to do with this issue?  I understand that the message is ambiguous in APM:Copter V3.3-rc10 but I have not been able to find a way out of it.  Do you have any suggestions as to how to track down why EKF is unhappy?  

          I have tried disabling PreArm checks entirely and thepre warning message persists.  The LED shows flashing blue when any GPS-reliant mode is selected prior to attempting to Arm. In Stabilize mode (as expected) the status LED is green and arming is possible. 

          I have on occasion seen the Pixhawk status light go green in GPS (Fence enabled) mode if I wait long enough.  Yet the HUD says 3D fix and Sats are >= 6.  



          • Developer


            Sorry but did you post dataflash logs anywhere?  Ideally with the logging-while-disarmed bit turned on.  It's likely that the EKF is unhappy with the velocities coming from the GPS but we will need logs to be sure.  The "Bad AHRS" message sounds like something else is going wrong (like an IMU).

        • Moderator


          Thanks for the explanation. I understood about Note #1, I wasn't concerned with the number per say, it was really the fact that I got it almost immediately upon powering up while I was indoors! That seems very unlikely.

          Any clarification on the units that the sonar values are when reported on the Mission Planner status tab? Or the pitch oscillation I'm seeing when I reach the value of WPNAV_LOIT_SPEED?


          Nathaniel ~KD2DEY

    • Yeah I autotuned roll and pitch axis with rc8 yesterday with aggressiveness set to 0.5.  Roll axis is OK but pitch axis took forever to autotune and now I get slow oscillation on the pitch axis when it recovers from significant pitch movements.  I'm going to re-autotune today with 0.7aggr and see what happens.

      • Developer

        Hi Fnoop,

        0.5 is way too high, that will be limited internally to 0.2. I hope you meant 0.05 but it is worth checking you didn't make a mistake.

        My suggested range is 0.05 to 0.1.

  • Has anyone else had trouble geotagging gopro pics via mission planner with 3.3rc8? Works well with 3.2 for me. When I tried with 3.3, using time offset, est offset always shows -1, then pre processing finds no matches. 3.3rc8 log below. 

    2015-07-30 16-45-21.bin

  • Randy, maybe it will appeal to you to compile something like 3.2.2 with most of the 3.3's non flight control related features like different gimbal serial  support, retracts and some other kinks? I think it is beneficial for both the AC project and us is users as we'll get some useful features on a hell of a stable platform, while you guys will get a chance to iron out any bugs in the said non flight control related features at the same time you will get some more time to work on the EKF and make 3.3 something really great instead. 

  • Hello,

    Is this negative baro readings are ok in flight?


This reply was deleted.


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