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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    • Developer

      Hi Richard,

      Sorry for the slow reply.

      There are a number of issues here. First up your hover throttle is too high, you hover at approximately 350 but you have your hover throttle set to 460. This will result in your copter jumping if throttle up while it is on a slope and also make it difficult for you when you touch down on landing.

      You also have very high vibrations. This will impact your Alt Hold performance and tend to cause the copter to wonder in altitude.

      Looking at your crash, this looks like you attempted to disarm the copter before the copter had detected a landing. You pulled the roll to the left, pitch down and yaw to the left. The copter then looks like it followed your commands. You then switched to RTL but by this time it looks like it had take a couple of knocks and no longer able to stabilize itself.

      I am sorry about your crash and hope this helps!!

      • I understand what you are saying about hover throttle, I recently took off a heavy camera and gimble and replaced it with a simple GoPro and Tarot 2D.   I hadn't  changed the hover throttle accordingly.. 

        I see the importance now..

        as to the RTL in the log,   I have it set so that It takes a second switch  to engage RTL, and I never use RTL so I don't know what happened  there.   When only using switch 1, I get only stable, Alt-Hold and Position Hold.   I'm sure I didn't engage it operating the second mode switch.  That puzzles me..  It seems like have seen other RTLs in my logs, and yet did not go into RTL.  The only other trigger is the receiver failsafe is set so that loss of signal will cause it to mimic the mode switch settings as when set to RTL.

        I am using the EZUHF LRS receiver, and I did a bind with the mode switch's set to RTL.  That is the method for setting failsafe for that receiver.   I don't think I had any problem with the radio though and I was not more that 20 feet way.

        Still puzzled.

        Thanks for your help.

    • Program a switch on your remote to be emergency motor stop. 
      I have serious issues w/ the landing detection, and my copters flip over, or bounce, or try to take off again, or simply don't slow their motors fast enough when landing.  I broke props almost every time I landed.  Now, I set it down, hit the motor kill switch, and everything is fine. 

      • Good advice! 

      • I just read my post this morning, and it makes the landing detection sound bad.  But I should mention, my flying area isn't completely level, and I'm often trying different props or flying without my camera, etc, so I'm usually causing my landing problems.  Controlled landings with a tuned copter on level surfaces work as they should.The motor stop switch saves me the rest of the time.

        • Developer

          Scott, Richard,

          honest feedback is fine.

          If you guys have logs we can have a peek as to what's going on.  As Richard describes there is a moment when the pilot throttle passes 25% (or 1/2 of mid throttle) where we suddenly turn on the attitude controller.  Leonard and I have a patch that attempts to smooth out the transition but it's a AC3.4 fix.

      • Hi Scott

        What you describe does sound like what is happening to me. On arming, and at first spinup, It sometimes jumps into the air before I am ready, or it may tip  over immediately on arming.  

        There is that critical moment when the attitude of the copter is in its side that things can quickly go very wrong as the copter attempts to right itself by going to full throttle. There probably will not be enough time to reach for a cutoff switch to stop a out of control multi rotor before it could easily do bodily harm if you (or others) are in its path.  

        Perhaps some logic code could detect that situation and shut down automatically.  That would be a very good safety enhancement worthy of adding to the code.

        • On Arming you can control how the props spin. In my personal case I regulate that to the lowest possible velocity that the combo ESC/Motor has a steady spin and it's low enough that no propulsion is generated.

          se MOT_SPIN_ARMED to control how fast the props spin on Arming. Some have the Mot_Spin_Armed disabled, but I really like it because the speed is not enough to cause damage 

      • Developer

        Hi Scott,

        I love it too :)

    • Hi

      Besides what has been said by Trent Russell there's something very strange on your vibration log that occurs right after you said you changed to PosHold. If you see the clipping that jumps at that time, I would say that something physical came loose and from that point forward the copter was trying really hard to keep up. 
      I know that now might be almost impossible to trace back where the physical fault might have occurred but look carefully at what might not be crash results.

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