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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  • Hi, had a crash/hard landing with version 3.3.2. The quad was flying quite nicely until the battery failsafe kicked in and the quad quickly became unstable and went down wobbling hard. The quad was below the configured RTL altitude at the time of the failsafe event. The log shows that the throttle output saturates and the angles don't follow command when failsafe begins. Can anyone here see the cause of the problem? Here's the Log

    2016-02-10 17-24-05.bin
    • your battery couldnt handle the current it takes to climb in the initial stages of rtl. It looks like you are using a very low c rated battery, and it was dead by the time RTL kicked in. Set your voltage failsafe higher to avoid this in the future.

      • Thanks Craig, I was indeed using a low c rated battery. Turnigy Multistar 10c 8Ah to be exact. 

  • Hi Randy and friends 

    Is it possible to change the height at which copter transitions from RTL to land .. I know you can set the land height to 0 for Land and RTL to a height to return at, but it is the section where it pauses to enter landing mode. I would like to change this height but I don't see any setting in MP for it. Is it possible?  


    • Developer

      So you're talking about the altitude at which it slows from the WPNAV_SPEED_DN (normally 1.5m/s) to LAND_SPEED (normally 0.5m/s).  I'm afraid the altitude is hard-coded to 10m above home unless the vehicle has a sonar in which case it will slow at the higher of 10m or when it first detects something below.  We could add a parameter for Copter-3.4 perhaps.  Just to understand the use case, I guess you would like to make it lower so it gets down faster?

      • Hi Randy !  

        Well, I would like to increase the transition zone to say 14m as its a very heavy large copter and when it descends its struggles to slow enough at the land zone height and we have one hard landing already .. I know I can set the WP Down speed but if i make it slower when it comes down from 200m its a long time for the descent .. so I have increased the WP Down speed and now need to raise the land section  from 10m hard coded to approx 14m.. unsure until its tested.


        • Developer


          Did that incident happen with a version before Copter-3.3.2?  In 3.3.2 we fixed an issue with how the landings were being done that should stop it from having the hard landings (see release notes here).

          • Yes Randy pre 3.3.2 on this machine we are still running the old version..I think it still on 3.2.1 :)  It was landing fine..infact we have done so many missions with this unit with no issue .. but it is a bit heavier now and i did increase the WP NAV down speed.. so it did no take so long to lose altitude after clearing some high terrain and enter its Land stage. Now it surpasses the safe height due to increased acceleration..Kinda drops like a stone and does not have enough time to pull up. and yes the copter has heaps of power and hovers around 450    

            • Developer


              Ok, so if you could give Copter-3.3.2 a try and see if it still has the problem that'd be good.  If it does still have the problem, just post a dataflash log and we can have a look.

              • Hi Randy .. I dont think posting a log would help, as I am sure its just descending too fast, to slow before Land kicks in .. It has been flying great for over a year now :o) 

                On a sad note a new Giant quad build  1200mm with 135kv motors and 26 inch props, after great month of flight testing on 8s packs flying with a 3.5kg load for 40 plus mins ! It was running 3.3.2.. It came crashing down today from 70m and there is not much left of it .. big dollars lost of that one :o( .. almost everything is damaged. We were flight testing some tuning to see if we could get it more stable when i think a motor arm rotated in the boss.. and it started spinning and doing cart wheels nothing i could do to save it .. here is the only photo I have of it in prototype stage..sitting on top of a 42inch telly :o) I dont think large Quads or copters do well as the larger motors and big props are too slow for fast changes required for good stable flight. I think using the same motors but on 12s with 20 inch props may do it :o)


This reply was deleted.


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