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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  • Part of this is cross posted from here

    I was flying on the shores of Lake Huron in Michigan today; absolutely gorgeous weather and flying conditions.

    Here's the flying condition:

     Takeoff launch position was about 3m from the edge of a cliff ~20 meters higher than the water.  Is it possible the difference in altitude from the launch position and the water is playing tricks on the baro and EKF/GPS?

    How do scenarios like this affect the barometer?  Once the copter takes off, does the barometer "see" this altitude change? Would lidar be a good addition to have in order to get a true altitude reading once launching from the cliffs? Today was a practice flight for a trip this summer to PIctured Rocks on Lake Superior in da U.P. where I want to get some nice video of from above the water. I find it difficult to judge how far above the water the copter is and wonder if the barometer provides an accurate altitude so my equipment doesn't end up in the drink.

    • Air pressure will not be different above (at your take off point) or beyond the cliff. Thus your barometer should read the same value and should not register any altitude difference once you go over the cliff and expose your copter to 20m altitude.

      Air pressure value changes from the mean sea level. Where you flew your copter was the same vertical distance from this sea level.

      GPS vertical data cannot be trusted at this situation either. So the only way to register the altitude difference in your case would be using some type of distance sensor (ultrasonic, IR etc.)


      • Thanks, I'm looking into LidarLite.

        I still don't understand how there can be such drastic altitude errors when using RTL/Land (by switch or Auto mission) in only a few minutes of flying. It happens at my home, field and yesterday at the lake and two different copters, one using Pixhawk, the other AUAV-X2.

  • Today I had a small crash with 3.3 RC3+: Before landing accidently I switched to drift mode. After landing I want to disam via yaw stick but the copter flipped on the ground. I think it should be possible to disarm the copter in every flight mode. I know thats stupid to land in drift mode, but when done disarming should be possible.

    Cheers Gregor

  • Looking forward to RC4  Best guess on when it will be available?

    • Randy is going to be trying for Sunday.

  • To all the developers, 

    will the "follow me" mode be smarter on the succeeding builds? I would love to see it perform better in follow me mode, like filming you from behind, or from your side. I think as of now, it is limited to fly above you. 

    just sharing my opinion. :) thanks again!

    • Nice! That's great news :) something to look forward to, :) thanks again.
    • Developer

      We are continuing to improve the performance of the follow me controllers. As Randy says, the rest is done from the ground station.

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