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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  • I'm having some strange issues.  I think it's GPS issues, but I don't see anything wrong in the logs. 
    It tired to fly away in loiter a couple weeks ago, and I've never figured out why.  GPS looked fine at the time.
    Today I was unable to switch to loiter.  I got "err flight_mode-5" in the log, when I tried.   Then, that same flight I was a little lost and flew out of radio range, and it switched to "land" instead of RTL. (It is set to RTL on failsafe) It did land successfully.   I had 3d GPS lock the entire time.

    Could someone look at the log and let me know if you see a reason for the flight mode error, or its inability to RTL?

    I've been flying this copter on 3.3 since about may, and haven't had any issues like these until I updated to rc10 or 11..
    but, I definitely can't say the issue is 3.3 related.   
    Thank you

    2015-09-13 19-09-41.bin

    • I saw something similar on the mission planner app with disarmed Copter:

      The position was about 50 m away from the real position. With the M8N I had fast twitching number of satelites (12 - 18) with HDOP below 1. There was a good view to the sky (outdoor) I leave the copter disarmed for over 5 min but the position was at a more or less same position still wrong. Then I repowered the whole system the problem was instantly gone. I did not have any logs.

  • Hi. This is a question for the developers but I´m not sure it is a 3.3 only thing.

    I have a big octa which has an extra battery for the gimbal and the pixhawk conected to an output so when I deplete the main one after flying, I can put a new one and I do not have to wait for everything to settle. The thing is that if the copter reaches failsafe voltage, it does everything that is supposed to (RTL) but once it lands, I can not fly again because the failsafe is not cleared even though the voltage is a 25.1

    Is there anything I can do? Or is it a software bug?

    • I have tried to the same thing with a backup battery on the 5v rail. I was hoping to be able to "warm up" the GPS on the way to the field and do hot battery swaps. So far I have found that I still have to fully power down in between battery cycles.

      It would be nice to have some way to warm up a multi with out having to have the main battery connected.

      This feature would be valuable to any emergency services use where rapid deployment is needed.
      This domain may be for sale!
      • Exactly. Another use is taking off from a boat. I need to start the apm on the shore to make the gyro cal and them move it.

  • Just had a crash...  I'm not sure what happened, but it wasn't good. 

    Let me try to explain a bit.  I have a quad, quite vanilla in design about 14in  MTM. Been flying it for about a year, its a good flyer. I have been flying the beta flightware (updating as each rc was released.) mostly just low level flights around the yard. I had 4 un-eventful flights on rc11 flightware in and out of alt hold and loiter modes many times.

    Today I decided to try a simple programmed mission and fly it from my android tablet, with the xmitter on and standing by.

    The Mission;

      Auto takoff, climp out to 250ft, loiter circle 2 times, decend to 40ft hold for 20sec. autoland. 

    I armed the bird from the tablet, OK,

    commanded the auto takeoff from the tablet, OK.

    commanded it to auto mode from the tablet, OK.

    All went well up to the final landing sequence. At this point (I think) it got below the tree line  lost some of the lower gps satlites and started to drift into a tree.

    This is where things went bad....

    From the transmitter (not the tablet)  I switched to Altitude hold, this caused the throttle to drop to idle and it dropped about 10ft. to the asphalt,  Splat......

    I was recording the GS video of the Heads-up display onboard, and looking, it clearly shows DISARMED in the display while it still flying.  


       Is there any cross checking between commands sent from a tablet and commands sent by the transmitter?

       can it be armed by the tablet and still think it's disarmed? 

       Or did I do something I should not do. Mix tablet control and Xmitter control?

       Or worse.. Did I find a bug?

    I will try to re-create the error condition again. ASAP.

    Flash log file; 63.bin

    Thanks for looking at this. and Thanks for any and all input/comments.



  • With rc11 I am not getting Land and RTL reported by the GCS when I am still on the ground. This happens in both MP and APM Planner. The modes work and I believe they are being reported when flying, just not before arming.

  • I'm trying to autotune a QAV250 on rc11 and I physically can't do it even though I'm doing one axis at a time. I'm using a 1.8Ah lipo which gives about 6mins flight time and each axis takes longer than this. I just about managed yaw, but pitch was still going when I hit the battery failsafe. Any suggestions? I can't use a bigger battery - it's already pretty big for this size of craft. Surely there should be a way of limiting the autotune time? Anyone have some reasonable numbers for a QAV250 that I could use as a starting point?

    • Developer

      Hi Andy,

      If you do one axis and post it here I can tell you where it got to before you had to come down. That should make it faster for you.

      The most important parameters to change for smaller quads is the filter frequencies:


      Set them all to 40.

      I have done a write up on setting up smaller copters here:

      • Thanks Leonard. I have now worked through your post in detail and will try again when the weather permits it.

        Roll is:

        P: 0.425

        I: 0.425

        D: 0.04

        IMAX: 200

        Stab RP: 3.469

        Pitch didn't complete so I assume it didn't capture any values?

This reply was deleted.


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