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 Randy,

        I have been flying mkblctrl quite happily on a hexa with pixhawk and 3.2. Now I have upgraded to 3.3 and the motors dont start anymore. I think a lot of people at least here in Germany have mkblctrl escs.

        Its sad that I have to downgrade now because a good and nice working thing is discontinued. I think one should be able to rely on downward compability when an update comes out.

        By the way I have your Solo and I think you have done a great job there. I am more than pleased.



          I agree that UAVCAN is better, but my ESCs have only i2c and it would be too generous of me to throw em off.
        2. Thanks. Kso... I guess I have to somehow put it on i2c bus.
        3. Debug is done better via CLI, I have to admit, that "Status" tab of MP is pretty far from ergonomic perfectness.
        4. Thanks, I'll try to see debug.
        5. Thanks again. I can help with Wiki if I'll have editing access.
    • Kinda intense topic...

      • Shoot, it really hurts to find your post with question in web search results while searching for solution :)

  • So I just swapped out my older Pixhawk for a new one hoping to get rid of the "bad gyro health".  Guess what, it still pops up.  It's not on the hud all the time, just pops up  now and again.  Maybe two bad Pixhawks?  Just connected to a small hex with a Pixhawk from about a year ago and the same bad gyro health after loading 3.3rc4.  Comes on for like 10 seconds and then disappears.  So all three autopilots are getting the same message.  No error message in the flight data logs and when the message pops up in flight and it doesn't seem to make any stability difference.  Do you think I'm safe to fly?  

    • Developer

      We're hot on the trail of this issue.  It's related to timing jitter and one of the gyros is slower than the rest (it's max speed is ~700hz).  The two together can cause that gyro to miss a sample which leads to the bad-gyro health.  It's not good but we think it's unlikely to cause a serious problem.  Of course it obscures more serious hardware problems so we've got to fix it.  I'll add a warning to the top of this discussion.

      • You guys seriously rock!  

    • If you look 1 page back, Randy mentioned that they were going to look at the code again as there have been a lot of folks mentioning this.

      I flew my IRIS on the rc4 code and got this error code too but it didn't appear to affect flight.  Loiter was really stable.


  • Hello.  I'm new to this forum but have a bit of experience after owning four quads including building two.  I realize that any beta firmware is a work in progress and subject to possible problems ("bugs"). I am presently flying a 3DR Pixhawk (not a clone) using 3.2.1 and wonder if 3.3-rc4 is stable enough to use for "standard" flying using the features like those available in 3.2.1 not the new capabilities being added and tested.  My setup is pretty standard.  Thanks for all you are doing in this exciting field.

    • My experience with 3.2 betas and testing 3.3 it is far more stable and dependable for all standard flights. 3.3rc4 is the evolution A&M copter and very well done. I have spent the day testing on 3 aircraft with no concerns at all in any flight modes or conditions. I have 5 high School Student teams flying APM and tomorrow we will upload 3.3rc4 in their quads, I believe it to be that stable.

This reply was deleted.


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