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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      • Thanks for looking over the log. I saw the the mag reading and suspected the same thing. I got a little anxious to see if it would fly and did not take the time to do the compasmot. I did switch to stab with no regain of control but I was near panic mode thinking I was about to auger in another high dollar build. Put it down in the grass with one broken landing gear so I really got lucky. We have heavy rain predicted for the next three days so I'll have plenty of time to complete the setup. Thanks for the help
    • switching into Stab mode would've given you full manual control stopping any autopilot initiated maneuvers. Also, since throttle in stab is manual copter is far less affected by vibration and absolutely not affected by bad compass, glitching gps or sudden pressure changes. 

      I too learned about stab mode the hard way :) 

    • I had a similar thing happen on one of the earlier 3.3 versions.

      Started spinning and would not respond to yaw after a hard maneuver.

      The problem was two fold, high vibration levels and the motors not level enough.
      This was on a folding quad, the booms pivots were wearing out allowing about 2-5 degrees of twist. Fixed the booms and found the vibration issue, flat spin problem solved.
  • Randy may I suggest an improvement for the next version of AC code, and where should I do it? 

  • test flight yesterday went well. except for this:

    copter triggers battery failafe then initiated auto landing. on the previous builds, I was able to override the landing by flicking one of the toggle switches on my taranis radio. that switch is intended to override the pwm on ch5, thus setting my flight mode to stabilize. supposedly it should have cancelled the landing sequence on failsafe. but it did not..

    is this normal? or is it a bug?

    • Developer

      I'm nearly 100% certain that it's still possible to change flight modes during the landing sequence of a battery failsafe.  There's "de-bouncing" on the flight mode changes though so if you switch the channel quickly away and back it may not register the change.

      • I will try to repeat this sequence later. I will fly  it at around 3 meters again, then wait until battery failsafe kicks in. I just found it weird though because I have been using this "panic" switch to set it back to stabilize before. But my test flight yesterday did not yield the same result. This morning I tried flying it again but still did not cancel the landing sequence. I will try to move my panic switch to another toggle switch on my Taranis. but I'm pretty sure my taranis is working fine, it's almost new.

        Can somebody else confirm this? I hope it's just me :) the latest build is very stable.

      • That's mean if the copter decides to Land for failsafe and you switch to another mode the copter abort land and fly in that mode?

        • Developer


          Yes, that's right.  It pretty much never ignores the pilot's requests to change the flight mode unless it's impossible to enter that flight mode due to poor GPS.

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