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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    • nice piloting skills there. Here is a short clip of my quad cruising during the rc7 release.

    • Wow!! I feel dizzy, impressive, the camera is cmos?

    • really good.

      are you fliing in acro mode ?

  • hi, is the a way to change IMU sampling frequency in AC3.3? for some reason I canoot find the old mpu6k frequency parameter. 3702079562?profile=original

    • Developer


      Yes, the MPU6K_FILT has been split and renamed to INS_ACCEL_FILTER and INS_GYRO_FILTER.  The way you use it is the same though.  I personally never adjust that parameter but my understanding is that smaller copters do well with a higher number to reduce the delay.

  • Developer

    Hi all,

    I added a discussion to sort out what we need to get Tri-Copters up to scratch. So if you have anything to contribute please go here:

  • First flight with rc9 seemed really good yesterday. Today second flight and hexa tilted over after lift off. It actually tried to tilt over just before lift off but I was able to compensate that. Same behavior on both flights.

    Also 12 minutes was not enough for autotune, didn't even get to yaw part. Previously that has been plenty.

    tilt log:

    tried to tilt & autotune log:

    2015-08-25 13-36-37.bin
    Shared with Dropbox
  • Hi guys,

    Sorry if this is slightly off topic.

    Just saw that the new Tarot T4-3D 3-axis gimbal is out.

    As it has an SBUS input I am wondering if the Pixhawk SBUS out port is fully implemented in copter 3.3.

    The wiki says it's not implemented yet, but there is a parameter BRD_SBUS_OUT, and I find out some info on the forums about it working, at least with ch1-8.

    The release notes also doesn't mention it.



  • Here's some information.. (I think everything is working as it should)

    I just did an autotune of a little 250 size quad.  (3.3rc9)
    With the aggr set to .1, it tuned fine, but then after saving the parameters, and trying to fly again, it always flipped over when taking off.  My CG is a bit off, and the back is heavy, so that's why it's having trouble.  I re tuned the pitch with aggr set to .05, and now it works perfectly. 

    FYI the CG is about a centimeter behind the center of the copter.

    • One more thing, I'm not sure if this is OK...

      I get "Bad AHRS" messages occasionally.  It seems random.  Just now, I've had the copter sitting on my table, and it was fine for the past 10 minutes, but now I'm getting the Bad AHRS message in MP.  (I haven't touched the copter at all).  It'll go away in a few minutes, and I'm sure it will return again sometime. 
      Same goes when I'm in the field.  Seemingly randomly I'll get the Bad AHRS messages, then they go away and I can arm and fly w/out any  trouble. 

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Shivchand Jaysaval liked Shivchand Jaysaval's profile
Aug 25