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 think what Randy is doing is a logic to have a dynamic adjustment of an angle_max depending on the ability of the platform to maintain altitude and it is better than an arbitrarily set angle, well, obviously assuming it will work correctly and reliably.

          a mode where this limit is enforced already exists - a generic 'loiter' mode. position hold is not the same.

          • A dynamic max angle adjustment of course would be the best way to handle the problem. But it also has to check single motor PWM because al least my Y6B looses yaw control before altitude drops.

      • altitude prioritizing would be well suited for 'boat mode' fyi. Lest we end up with the perfect vid shot right into the drink. 

      • Sure, why not. Probably good logic would be to gain back to original altitude after detection of an altitude sudden drop and if if goes up and down within a meter of so, it is not a big deal, as long as it done smooth.
    • Did you check your vibs? I have that problem with vibs in one cuad, I hope the y ones do that but not shure, what shure is I have that problem when vibs aren't constant.

  • My current setup is a tbs discovery frame with stock dji arms, 1045 carbon composite props. What is the recommended value for Aggr? I would like to set it before trying autotune. Thanks in advance!
  • Hi devs, I'm not able to do autotune on rc7 without sending my quad wobbling to the ground. First few steps on roll axis seem normal but then it looks like it gets a diagonal step and becomes unstable. Is this maybe a hardware issue? 15inch props, 470kv motors. Using default parameters except aggr 0.05, but same problem with aggr 0.1. The log is attached. 

    2015-07-16 22-11-12.bin

    • Developer

      Hi Arni,

      Sorry for the delay in my reply. This is almost certainly caused by poor starting tune. You are getting an oscillation that is coupled between the two axis. The scary part is it looks like it is getting started by a sync issue in your front right motor.

      You may be wise to tune this copter manually until you are confident you don't have ESC sync issues.

      As far as I can see your Arducopter setup looks sensible.

      • Hi leonardthall,

        I'm trying to learn reading the logs, and I'm wondering: what info in this one shows that there is a sync issue?

        Or even better, how can I now that one of the motors has a problem, sync or something else?


        • Developer

          Hi Igor,

          I look at a couple of things but mainly I am looking for movement in the copter that doesn't match the motor outputs. This is pretty clear during autotune because I know that before each twitch the copter is level and not moving much. Then it gets commanded to move in one axis only. This is then followed by a movement back to level. So if I see any movement other than the single axis I look for signs of a poor CG or a motor sync issue.

          Now I go to looking at the motor outputs. The symptom of poor CG I am looking for is a consistent mismatch of motors, generally forward and aft motors.

          If I don't see this then I look at the time the copter moved from it's desired axis twitch and look at the motor outputs. Generally I see a significant difference between the last twitch and the previous twitches (generally I have been given a crash or near crash so the autotune stopped after the twitch with the problem). The normal twitches show a clear motor output to cause the copter to accelerate in the desired axis. The problem twitch generally shows a very different response as the copter tries to level itself. It is normal to see the motor with the sync problem going to maximum but that arm still dropping.

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