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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    • Niether of my Lites have "that" issue but both get BAD AHRS on bootup. Sigh. It eventually clears though.

      I WAS getting that error though and it was odd because I was just using the internal compass and no external which makes me wonder how it could have a bad variance. I flashed back to 3.1.5 and did a console erase and reset and then flashed 3.3-rc10 and that part went away.

    • I have one of those, and running fine.

      Calibrate mag as instructed on the wiki. 

      On my small 330 Quadcopter that I've been using to test 3.3 the ESCs are right below the PixHawk lite so I added a small aluminum self adhesive foil below the PixHawk. Note the small post for the GPS+Mag (a BG880 unit).

      The mags are reporting some sensitivity, and at 2 meters from my car the Compass Variance would go nuts, affected by the large metallic mass....3702593867?profile=original3702593665?profile=original3702593750?profile=original

    • Scott, I experienced this as well, when I build a copter for a friend who eagerly wanted this cheap FC.

      It turned out, that the internal MAG wasn´t working although it showed up with its dev_ID @ MP. However, when I did Compass calibration, it didn´t really show up (MP claimed about 10 samples), so its really unsuable, although present.

      Maybe, if there would be a way to turn the internal MAG off by AC, Variance message would not appear.

      Nevertheless, since this PIXHAWK Lite V2 came up with random Bad AHRS as well, even sitting still on the desk and presented a SELF TILTING horizont (sometimes so that power leads have to be shorted), I m going to RMA this pos.. Maybe the builders used 3rd choice LSM303 (located right beside the MS5611)...and the next one is better.

      Despite of that, it does fly ;-) (Well I turn off all PA checks anyways.)

      @Alberto: USB is working fully @ the one I described above. Production Variance ;-)

    • Hi, my "Pixhawk Lite" don't have this error but need to by connected to the power module to work properly. The USB connection is not in-of to make it work.


  • Hi Randy.

    I have a question. If posible change the range of _radius variable to take more radius in circle mode? I´m traying to do a circle on a rock that is in the sea, near of the coast, but it has more that 100m. Can you help me? Thank you so much.…
    • Hello.
      All fixed, with MissionPlanner have created a circular route with waypoints

      Thanks to all.

      • If you use splined waypoints it should work out pretty well.

    • Chris,

      Reread your post and realized you were using circle mode and not a ground station program or app.  You could probably get your shot using one of them.

      • Hi Greg.
        Thank you for taking your time to answer.
        The problem I have is that Tower is not possible to perform the mission because it allows the maximum radius is 50 meters, in APMPlanner2 the maximum radius is 255 meters and MissionPlanner can not send the mission to drone because it gives an error; Looking at the complete list of parameters see that CIRCLE_RADIUS Variable accepts at most 10000cm do not know if I can define it by a larger number, I need it 40000cm.

        Thank you.

    • What are you using to setup you flight, Tower, DP or MP?  Might want to take the question to the appropriate forum for whichever you are using.

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