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 got that every now and then on rc-9 but do not seem to get it on rc10. Also after you unplug your lipo use a paper clip or something to short the leads on your connector to fully discharge your MR as some have said this solves the issue.

      • You might want to be careful about your wording when posting advice like this in case someone interprets it wrongly and explodes their battery :)

        • Any one who read those posts and thought they should short their battery as a pose to shorting the copter leads, likely should not be flying any thing more than a phantom any way.

          I do get your point though.
        • I understand what you are saying but I would think Darwin would sort that out pretty quickly :)

          But you're right. When I say short out the leads I mean the ones going to the copter/plane NOT the battery. 

      • I get the bad AHRS message, bad gyro, and GPS health frequently on multiple firmwares.

        Unplugging the battery and shorting the leads seems to clear it up most times, other times I have to repeat the process as many as three times.
  • There are other issues on the flight but from what you told us, I believe this was the moment things began to act strange. Also to note, that the controller appears to have some brownouts, but I didn't look at this with care.


    • Luis, are the brownouts that you are referring to the red spikes downwards?  I seem to have always seen these, so much that I thought maybe it is just a sensor glitch, they are never more than a sharp spike.

      Also, I know that other than the unexplained climbing and descending motion, the vehicle didn't got to full throttle and fly around like crazy for 2 or 3 seconds until the very end of the log. The last mode change was from stabile to alt-hold, and then when it touched down, all heck broke loose. I agree, it seems like a sudden displacement of the CG, like something falling off could have the vehicle reacting in this way.  It makes me wonder if it was the camera and gimble.  It will be hard to determine now, they were thrown from the wreckage..

      I'm pretty sure this is not a 3.3 issue now, so sorry I brought it up here. 

      thanks for the help.


      • Don't know. It's always a case by case that has to be "traced" :) In this case it might be just a glitch because the other power parameters don't show anything:


  • Sure, plain APM Planner 2.0.18

  • I had a very violent crash today while flying my 750 size quad.   I am currently using 3.3rc8 on this one.

    I have flown it about 3 times on this firmware and it was very stable.  The wind conditions were light and variable.  

    this time, I began to wonder when I first tool off, a slight gust came up and It tipped over backwards.  on a second try, it lifted off and seemed very stable (in stabile mode).  I switched to Alt-Hold at about 10 feet, it seemed to be fine so I went to PosHold.

    Also fine, but I was showing friends how it could hold position then it started loosing stability in the Z axis.  It dropped i altitude pretty quickly and I took a bit of stick to stop the descent.    I stopped so I tried to get it to stabilize, flipped it back to Althold.

    then I decided to land, and forgot it was in AltHold. It landed and I reached to switch it back to stabile, and the copter spun up again, tipped back, then went to full throttle.  I was about 20 feet away and I started to duck, but it went but me so fast I didn't had time to take cover, I was just blessed that it missed me.  (this is a 6s powered system with 15 inch carbon props, and 380 Pancake motors and it is lethal at full power.  It then headed towards my group of 5 friends and just by the grace of God missed them too. it was all over the place, ended up reversing course several times, barely missed me again on the way to destroy my ground station and finally hit some pavement, flipping a few times until it slung the battery off.  

    All this happened in about 2 seconds..

    Once I was able to declare it officially dead, I started picking up the pieces.

    I feel that the beginning of this sudden destruction was cause by landing in Alt-Hold.  Is that possible?

    here is the log, I hope someone can help me understand what pissed this copter off.  I'm afraid to power this beast up again..

    (there is a lot of dead time where I am waiting for GPS lock and getting the ground station set up)


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Shivchand Jaysaval liked Shivchand Jaysaval's profile
Aug 25