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


                    You're right in AC3.2.1 there's no COMPASS_USE2 parameter so there's no way to disable just the compass consistency pre-arm check.  So the only way around it would be to set the ARMING_CHECK to Skip-Compass which disables this check plus all other compass related checks.  My guess is that with AC3.2 just waving the copter around a bit will also let it get past the compass consistency check because it's not that strict... it's meant to catch really large compass orientation errors.

                    ... this is just a pre-arm check .. not sure this is really worthy of an AC3.2.2 release at least not on it's own.

                  • re- Both AC3.2.1 and AC3.3 will actually never fail-over to the backup compass so it's really just a matter of ignoring the internal compass during the pre-arm checks if it's been set to COMPASS_USE2 = 0

                    I'm flying 3.2.1 and don't see COMPASS_USE2 ?? 

                    I see COMPASS_PRIMARY

                    then COMPASS_USE

                    but no COMPASS_USE2

                    The fix should be added to 3.2?? Our point??? 

                    also note related here

                    re- boat take off THANK_YOU_X100



            • Hey Rainer,

              After watching the video you posted, I came a cross the below one.

              Many people saying it is fake. I don't know why would someone go through all hassles to make a fake video. These things happening even with super expensive systems because those expensive systems aren't the best. They are just expensive!..


      • Developers, please, please ignore this ridiculous request.  The rapid and bold development made over such short timescales is nothing short of amazing and the stability is incredible given the complexity involved and potential for regressions and bugs.

        There is a perfectly good stable branch/release for those that want to use stable code, used by thousands out there with excellent results.

        • Developer

          Thank you!

        • So ridiculous it's been done many times apparently. lol

          It is nice that this forum is ussually polite and courteous to all views.  Much more so than most. I think we should all try and keep it that way. 

          • @Richard,
            Did you get your Taranis Mavlink sorted out? I sent another reply but it was buried in the thread. I have my Serial2 protocol set to 2 instead of 3 which makes no sense as 2 is not even listed in the wiki listing. Can't explain it but it works on all of my aircraft. Let me know how you come out on this, sounds like we are in a similar place.

            • I tried that and it did start to give me data but then it keeps giving me strange audibles that make no sense. I'm using a script from droneshop must be a glitch with that. But thanks for the tip!  That is odd it works for you but so long as it does who cares :] I ended up going back to 3.2 for now and for some reason I no longer have the DCM bad heading problem!! Who knows why but I'll take it!

        • Thank you:)
This reply was deleted.


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