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 will make the suggested changes and give it a try, the Pix is mounted on one of these (link below), not sure I can try something better...I have always struggled a bit with minimizing vibes on this copter (Tarot 680). Winds are calm today so it wont have the same issue, but they should pickup tomorrow again....thanks a lot for looking into, you guys are awesome!

        one more thing, should I try AUTOTUNE first also?

        • What is the AUW, prop size and brand?

        • Developer


          Great.  No need to do AutoTune I think at least in order to resolve this problem.

          Thanks for providing the link to the vibration mount.  We can't be completely sure because each copter is different but from the vibration data it looks like this solution is not as good as the 3M foam or hobbyking orange foam mentioned on the vibration wiki page.

    • Developer


      Thanks for the report.  That really does look pretty terrible with the vehicle oscillating quickly in roll and pitch at a couple of times in the flight.  I suspect reducing the WPNAV_ACCEL to 100 will help but it's current value of 200 doesn't seem high enough to cause this problem.  I'll have a chat with Leonard about this and get back to you.

    • didnt attach log, here it is


  • Hi Randy, loaded RC10 on my Y6 with U8's running 28 inch props, flew very nice over 3.2.1.  I especially liked the smooth throttle handling on Loiter take off and landing. Will conduct autotune tomorrow.

    I notice that RC9 now has support for Lidar Lite V2, does this mean we can now connect the V2 via I2C?

    • Developer


      Thanks for testing.  Tridge and TomP have been testing the lidar-lite and he I2C reliability of the V2 seems better than the previous version.  They've still seen situations though where the sensor is suddenly reporting a 13m offset from it's actual distance.  The cause & fix aren't clear yet, but it seems voltage related and the issue is certainly within the sensor itself.  Basically, I guess I'm saying, we have a driver for the V2, you're welcome to try it out and we'd appreciate your feedback to see if it matches what we've seen.

      • Hey Randy,

        I've been testing the V2 via PWM connected to the Pixhawk (using master branch). I also see the jump, often to 12.02m. I also see the PX4Flow Sonar jumping to 12.02m.

        Did you guys also see the jump via I2C, or only via PWM?

  • I have NO idea why this doubled posted. Sorry.

This reply was deleted.