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 have been running for a few days with no issues.

      Have about 8 flights and about 2 hours flight time with no issues.

    • I've done a half dozen flights with my quad and hex with no problems. Very stable and prdictable. Auto missions are solid however I did not try to replicate the bug.
    • Tried it on Thursday and didn't notice any difference from 3.3 for me.
  • Ok, below is the real and not fantasy VIBE results after making some adjustments in the FC mounting. I tried AT with the earlier VIBE numbers, and that didn't work out too well. It almost flipped and did other odd things.

    Tonight I flew with the below vibration results, but too windy to AT. One noticeable event was it occasionally would Yaw as if it were trying to adjust the heading. It did that with the high vibrations, so I chalked it up to that. What usually causes a quad to Yaw without sending a Yaw command?


    • Developer

      Yes, like Cala says interference on the compass from the motors is one possibility.  The other possibility is a large-ish motor imbalance.

      If it's compass interference then you could see it in two ways:

      1. the easy way is check the live EKF viewer's compass variance during one these yawing events (MP, Tower and AP2 all have live EKF viewers now).  If it climbs dramatically then it's probably interference.
      2. the more direct way is to look at the dataflash logs and compare the CTUN's throttle out with the mag field length. The mag-field length can't be graphed directly though, it needs to be calculated (I use excel) using =sqrt(x^2+y^2+z^2).

      The motor imbalance is quite easy to see from the dataflash logs.  Just take a log from a vehicle doing a regular hover and plot the first 4 channels of RCOU message (assuming it's a quad).  If the distance from the highest to the lowest motor is over 200 or 250 then the motor imbalance could be the cause.  Perhaps one of the motors is tilted.If you post a dataflash log I can peek at it if you like.

      • The motor imbalance is quite easy to see from the dataflash logs.  Just take a log from a vehicle doing a regular hover and plot the first 4 channels of RCOU message (assuming it's a quad).  If the distance from the highest to the lowest motor is over 200 or 250 then the motor imbalance could be the cause.  Perhaps one of the motors is tilted.If you post a dataflash log I can peek at it if you like.

        hi randy,

        that´s sound interesting to check the tilted motors.

        can you explain it with a picture. attached is a log of me. it´s 3.2.1. i hope it´s ok in this thread.

        thank you very much

        2015-10-25 14-45-25.bin

        • Developer


          Here it is for the log, it shows an imbalance of about 100pwm which is fine.  I encourage you to try it yourself though, it's really very easy to produce these types of views.


          • i found´s new in beta mp

          • hi randy,

            my log browser looks a little bit different. i can´t see the values on the top. and from where comes your value of 100pwm at your screen? is it the different between ch1 = 1438 and ch4 = 1520?

            i´m using mission planner, not apm planner.

            best regards


      • Yes, I like the EKF viewer feature. Today it was quite windy and I was just glad to land before it ended up in the woods or a tree/barn......landed and totally forgot to look at the EKF stuff.  

        I didn't post the VIBE from when I did the AT yesterday, but they were ridiculously high with lots of clipping; don't know why it got worse from the other day, but the AT was aborted after the acrobatics show.  That prompted me to redo the FC mounting.

        This is from the AT attempt.

        sANwhtu.jpgAttached is the short flight from today. Thanks for looking at it. BTW, others have told me these Alien frames are a bit cantankerous to tune. I hope not. 

        2015-10-23 18-09-55.bin

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