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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          • Haha as it happens the same although mine are version 2 which I believe are not flashed with simonK, I am thinking of changing them out as I have the version 1 on my fun machine and I'm sure they make for smoother motor performance

    • Developer


      Thanks for testing.  For the gimbal could you set the MOUNT_TYPE to "1" and reboot the board?  That should get it working again.

      • Hi Randy, I did this yesterday as per your advise to my previous post and it didn't solve this issue.

        Although the Gimbal LED is now showing that it is connected to the pixhawk (flashing blue not steady blue) any other ideas?



  • All right, being fueled by so many great responses on AC3.3 autotune, I decide to give it a try last nigh on one of my machines. It is a large-ish (750 size)  tricopter running on 6s lipo. Took off the gimbal, put a dummy weight in its place, made sure nothing is able to move on the air-frame and went to the park to do the autotune. I can say that the values autotune returned on pitch and roll are definitely not ideal, but certainly flyable, on the other hand yaw is a total miss, much delayed reaction + big overshoot. Need to say that the last firmware which gave good PIDs for any tricopter was 3.1.5, is there any way to take the best from 3.1.5 into 3.3?

    Thank you! 

    edit: here is the link to the log

    • Developer

      Hi Artem,

      Could you provide some logs and a couple of photos of your tri.

      I have not tested auto-tune on tri's but I am about to build one so any feedback you can give would be great.

      • here are the pictures: 

        the ****hawk is replaced now with AUAV-X2 

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        • Developer

          Hi Artem,

          Yeh, sorry about how long it has taken me to build a tri. I have ordered another one that should be pretty similar to yours without the gimbal. The frame I had was going to be a pain in the .... to mount the pixhawk on and the tail servo arrangement sucked.

          The tune you supplied looks good for roll and pitch. I suspect that a big part of your problem is you have RCFeel set to 100. I would suggest dropping it to 25 or 50.

          On the yaw tune. Again Autotune looked like it did an ok job of it. However it wasn't designed to handle tri's. When the cg of the rear motor is higher than the pivot point the copter rotates slightly in the wrong direction before starting to rotate in the correct direction. I haven't tried to approach this problem yet.

          Could you give me an example of your yaw tune with parameters you think are good vs the ones from your last tune.


      • HI leaonardt, thank you for looking into this. You might remember we already spoke couple of time regarding autotune on tricopters. Couple questions, do you need some of the regular logs as well, or only those with autotune? 

        I will reattach the 3.3 rc4 autotune log here. 

        edit: and last 3.2.1 atotune as well

        2015-05-20 18-47-20.7z

  • A couple more tests on the bench.

    As suspected, once the unit warms up, a power reset shows less altitude deviation, it only climbs to about a meter in a couple of minutes and stabilizes. But it doesn't reset on ARM.

    • I had this happen a few weeks ago on a new DIY Pixhawk quad build running 3.2.1.  Was causing false altitude reports and RTL did not climb to min altitude before starting the return flight.  Had a few RTLs at 6 feet altitude.  Fortunately was in testing mode so NHNF.  Ran the MP Terminal Baro test several times and it clearly showed the altitude drift.  Thought it was a bad barometer module so I contacted 3DR for a warranty replacement.  They asked that I send the log files which they analyzed and reported back that the log files showed that all was well.  Did not see in the logs what I and my friend who was there observed.  The tech (who was very nice and supportive) asked for a video of the reported behavior along with the log file.  Went to the field to make the video but when I triggered RTL, all worked properly.  Made three attempts without "bad" altitude behavior.  Strange but true.  It's been working fine ever sense.  I guess 'Quadcopter heal thyself" is a hidden flight mode we didn't know about  :>)

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