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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    • Distributor

      Hugues - that's really great - thank you very much for the detailed analysis!

      What is the manufacturing date of the sensor which you are using?

      I think we have to check as well the maximum distance which the sensor can reliable measure (maybe the 40 m stated by the manufacturer are not correct).

      Would it be possible that you use your set up with the Arduino board to check that one too?

      • MR60

        The unit is manufactured February 2015.

        • Very nice chart. I have the same results - Arduino -> very accurate; Pix -> ~ +40cm to real readings. Mine is a Feb 2015 one too, connected with PWM

  • Developer

    Henri (replying here re the Parachute instead of back on page 42),

    I've reviewed the parachute code and there were a couple of issues I found which I hope I've fixed.  Not saying it's perfect now but hopefully a little better and I'm happy to address any other issues you find.

    • it was using the altitude above the "EKF origin" instead of the alt-above home.   Normally they're close but not always.
    • increased the duration that the servo/relay is activated to 2seconds
    • better error message if the parachute won't deploy because the vehicle is landed

    I tested it using the wiki instructions and it seemed to do the expected thing.  My guess is that that problems you're having getting it to deploy are related to the vehicle thinking that it's landed.  Especially if the CHUTE_ALT_MIN is set to "0" it removes the altitude check completely (but it still doesn't remove the landed check).

    I had a peek at your log files but there were so many there I wasn't sure which to look at.  Also could you set the LOG_BITMASK to "All+LogWhileDisarmed" just for the test?   This'll give me some more information if the parachute is deployed while the vehicle is disarmed.

    By the way, the modified firmware (good for benchtesting) can be pulled from the Mission Planner's "Install Firmware" screen by pressing the magic "Ctrl-Q" keystrokes.  It should appear as "AC3.3-dev".

  • T3

    Fully OT: I just had a look at Github and realized the incredible number of commits since APM 3.2.1.

    Looking back and depending on the function, APM 4.0 will contain another 35000 - 60000 commits :-)


  • Is a fix for accurate LIDAR Readings (PWM Method) on the worklist for 3.3 Final? I am thinking about adjusting the lidar by itself, but then I have to disamble the full copter again, when it gets fixed.

  • does anybody know how many amps a BEC should bring for pixhawk?
    i think i have just burned my voltage converter RECOM R-78B5.0-1.5L (1.5amps), this was so bad, suddenly the light were off and pixhawk shutdown. i could only look to my copter falling like a stone from the sky.
    up to this point I had no problems.

    • Hi Rob, thanks for your reply. The disassemble has shown that the problem was not the DC/DC converter but the solder joints on the attopilot.

      See below what happens when 160Amps are hitting a small plate. Next time i have to fill all with solder, Lesson to be learned. 


      • That's a real shame.

        I constantly advise everybody to NEVER use a current sensor like that on any machine that draws even half the rated current of the sensors.  They are just not reliable, and the failure mode is terrible.  The usefulness of the data from a current sensor is not high enough to outweigh the risks.

        I never use those on large machines, just my small quads.  If you really want current data, consider using the Amploc series of sensors.  I have one on my large Octocopter.  It poses zero risk of failure, as it simply slips over an existing wire.

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