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

      Hi Ron,

      There aren't any plans to add anything to 3.3 at this stage. Any adding is only happening for 3.4.

      I like the idea though.

      • As far as I remeber the code is already there, just needs a custom compile.

        • Developer

          Grant Mophett and I were looking at that PR just yesterday.  It's a small change but it needs to be modified a lot to fit in with the new AP_Mount library structure that we put into AC3.3 to allow support for various types of gimbals.  Of course, with the new structure it fits in much better.  As Leonard says though, it'll be an AC3.4 thing.

  • Hi. I'm trying FRSKY s.port telemetry, telemetry may be sent before arming? Or is it only possible after arming?


    • Developer

      Hi Chris,

      I use the earlier FRSKY telemetry and it is sending data as soon as the autopilot boots up.

      • Haha, while we are at the frsky telemetry (old). Please, advise what is the correct baud rate for it. I am using it on one of my machines with openlrsng setup which fully supports frsky old telemetry, but I believe due to incorrect setrinngs either in AC or in the radio I get garbage values every now and than. I've asked at the frsky telemetry threads and they say it is 56k, but MP sets the serial port to 9k when I choose frskytelemetry. Thx! 

    • Developer

      I've actually never personally used it but from a peek at the code I think the FRSky telemetry should always be sent whether armed or disarmed.  Happy to be corrected though if someone else knows better.

  • Hey guys, I had something strange happen with auto tune today. I was flying 3.3 rc9 and having a grand ol time, but decided to go for a roll axis autotune in order to hopefully iron out a Teeny tiny little roll twitch. I adjusted the autotune axis to 2 and flipped my channel 7 switch to start autotune. Auto tune started but started with pitch... this isnt what I wanted so I killed autotune, landed and double checked the parameter via Tower. I showed 2 so I took off and tried again and it started to autotune pitch again. Thinking I might have remembered the parameters incorrectly, I changed the autotune_axis to 1 and went for it again. It still started pitch so I shut autotune off by flipping my channel 7 low again. Now, the thing that really bothers me. At sometime during all of this on and off with autotune, my pitch parameters were actually changed and my quad started to oscillate to the point of discomfort, but not enough to cause issues getting it back on the ground. I never landed and disarmed while in autotune. I never even completed autotune, but my tune was definitely altered. I really don't think it should happen like this, and hopefully there is an explanation as to why. 

    Incidentally, I have never had a favorable outcome from autotune. It always yields a flyable craft, but it is always twitchy and always has to be downtuned substantially. My current quad has been manually tuned and actually flies really nice, but the same rig flown on the results of an autotune tend to cause substantial amounts of anxiety. 

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