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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        • As I'm a control freak :-) I always takeoff/land in stabilize.

          But as I am mostly flying in highlands, before flying missions, as a SOP I always arm and takeoff in one of the GPS modes first, to make sure I have a good GPS lock

          • I'm the same way I can't STAND the idea of taking off in any other mode except stab. Then I get it to where I want it. Then switch to alt-hold, or loiter, or auto etc. Took me FOREVER to allow it to auto land land and I STILL rarely do so unless I init RTL or end a mission.

            • if you engage RTL in the end then it is absolutely required to change routine and engage GeoFence so firmware will not let you to start and fly until system acquires acceptable GPS lock and gets your initial position correctly, otherwise your start with GPS coordinates from who knows where may result in RTL into who knows where.

              GeoFence is annoying as it takes forever for it to finally acquire that '3d Lock', whatever it is, as it may sit 5 min or so having 13-14 sats in 3D mode before it finally satisfies, but afterward it is flying OK.

              Also, after my fights with drone doing toilet bowl and other GPS glitches - an only solution is to buy a separate BEC with a _very_ good LC filter and power your GPS units from that separate BEC, not from your flight controller COM ports. Difference is quite dramatic, in both speed to acquire locks and with in-flight stability.

              After all that done I am now always start in position hold and vehicle does not dart sideways anymore, does not try to fly away anymore either. Only other thing - on dual GPS vehicles you still need to change the option to disable automatic GPS receiver swap function until Randy and Co will change logic not to use actual physical coordinates from GPS units but an average delta between positions GPS units return, as different GPS units never return same actual number for coordinates no matter what you do.

              Code really needs  to be adjusted to take care of that - to trace actual movement delta from both units and not actual coordinates value as latter results in the drone darting from one stable position to an another. 

              • Hi
                I us a Ublox NEO-M8N as my main gps which gets 15 sats in my living room and a second 3dr gps which is still thinking about getting a lock in the house with gps auto switch on it never actually switches gps but 3dr one is there should the m8one gps one fail as I go a couple of miles out best be safe than no backup
  • Loaded 3.3.2 rc2 on my 450 and 550 quads. Autotuned both and flew a bit this afternoon.  All went well.  Only thing I saw was the 550 tended to have a minor  "quiver" side to side.  Probably a slight vibration problem.  Was testing new props.  Will fine tune and recheck but believe that it is my problem not 3.3.2 rc2.

    Thanks Randy & team for your excellent work and fast turn-around.


  • today more flights, more test switching to stab and pos hold and works well

  • Anyone run autotune with parachutes on board and armed?  Just going to autotune a new rig that happens to have dual Skycat's on board and wondered if it would be a good idea to take them off.  Wouldn't be all that great if they fired lol!  The chutes are designed to save the payload...  But not the multi rotor so much at about 17'/sec.

    • Yes, I run autotune with parachutes on board and armed, no problem

  • Is there no THR_MAX parameter in 3.3.x? I have gone through the wizard for a Hexacopter in X, but my parameters do not include a THR_MAX and my copter will not take off (motors spin and almost take off, but do not).

    Attached pic showing no THR_MAX after using the wizard for Hexacopter in X. 

    • Anyone else any thoughts? I have done tons of searching, but no luck getting any closer to finding this setting.
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Aug 25