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 you Cala for your answer. I would be grateful if you could share your PIDs. We've got different props but i thing pids could be similar (not equal).

      so if i'm flying with gimbal should i adjust pids manualy for only one axis? for example first for pitch and than for roll?

      how to start? First from P? or I? or D? or Stab? :) a lot of question for such a "little copter":)

      • This my pids: I'm not an expert but, perhaps give you an idea to begin, Pitch is higher (in my case and yours) because the copter have to do more esford to move on that side, batteries are larger to there and a camera, gimbal etc. first to tune be shure that your center gravity is correct in both sides, set your gimbal as near as the main plates as you can; as Leonardthal recommend, do a first autotune and then a second one to fine tune; if you don't like your results, download them by steps, the axis that you don't feel comfortable, you have an easy basic tunning page, try with it first

        3702723778?profile=originalThis only an orientation, remember that I don't finish to tune yet, but flies good, Good luck 

        PD: here you have an autotune topic with good information and where you can post your tune advances

    • So here is photo of my build.


      and log file

      hope link will work


      thanks a lot!

      • Very similar than my new build

        I did autotune but without the gimbal in front, then I lower stab pich and roll and rates pitch and roll but pitch stay higher, then I try a second autotune but abort in roll for a lost signal problem and now waiting a calm day to re do for a fine tunning but the copter is flying well, I have to put a cover, look my post. If you want, I can share my actual pids

    • Perhaps it's usefull if you share a photo of your build, It's looks strange that you have so higher values in Roll than Pitch, did you complete well Pitch and yaw autotune?

      It's usefull for experts if you share your autotune log too. 

  • Developer

    Ok, there seems to be a problem with the centralised builder which is stopping the release candidate from appearing in the mission planner.  It's getting late in Asia so I suspect it will be a 12h+ delay before it's out.

    • Randy,

      Thanks. I run into this issue earlier, and was stump, not sure what had happened. 

    • Thank you for the effort Randy!

      I had this bug once. i was ready to take off then a storm of birds was passing by so i immediatly abort the take off.

      At re arming the iris took off immediatly. I take it down with the rc controller due to the strange fact and then i power cycle the iris. By luck i didn't engage the missions stored on the iris after the strange take off.

      • Developer


            yes, you got lucky there.  That's the exact case where it gets itself into a bad state.


            ok, sorry for the troubles!

        To add a bit more detail, internally Copter has an auto-armed flag that should always be true if the vehicle is flying autonomously.  It's primary function is to stop the vehicle from beginning an autonomous mission unless the user has raised the throttle.  In the case of the take-off being initiated from the ground station we were not checking that flag.

        Copter-3-3.1-rc1 has appeared in the mission planner so all feedback welcome.

        It actually has some additional changes beyond this fix:

        • compiler updated to 4.9.3 (code runs slightly faster than with older 4.7.2 compiler)
        • TradHeli changes ahead of next round of beta testing (should not affect multicopters)
  • Developer

    We've found a slightly obscure bug in Copter-3.3 caused by a few missing checks in the take-off controller.  Thanks to Stephan for uncovering the bug and providing both dataflash and tlogs which helped us find the bug.  Thanks also to Jonathan Challinger of the Solo dev team who pinpointed the cause.

    The sequence of events to uncover the bug is listed below and also in the video:

    1. Leave transmitter throttle at zero
    2. Arm from the ground station
    3. Take-off using the ground station but then immediately disarm
    4. Arm again (vehicle takes off without Take-off button being pushed!)
    5. Switch to Follow-Me, Auto or Guided and the vehicle falls out of the sky

    Pretty much this exact sequence is required so there are a dozen ways to *not* hit the problem including these two:

    a) Raise transmitter throttle above zero when using Guided mode


    b) Don't abort your takeoffs.

    Copter-3.3.1-rc1 which includes the fix should appear through the Mission Planner's beta firmwares link within a couple of hours.  It would be great if people could give it a try and then we will make this the official version within a couple of days.

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