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

      Zero issue with the same hardware, check your wiring and the component position.

  • Well since nobody asked this it seams.. why not let channel 6 tune atc acceleration values just like rates or stabilize?
    • Developer
      Hi Adolf,
      That is a good idea but ch6 tuning is probably a bit of overkill for the ATC_ACCEL parameters. Most people will leave it at the autotune values or have particular backed off numbers they like.
      If enough people request this feature I am sure we will add it but at this stage I don't think it is necessary.
      • The idea came to me because some users get that jump when they yaw and to fix they need to tune the yaw acceleration. Would be easier to do that in the air.
        I was mainly talking adding the ch6 for the atc yaw acceleration only. The other axis... yeah.. lol
  • Help needed here.....a bit of LOL, but can't figure this one out. I don't know what the heck happened, but this is the first time one of my copters completely freaked out running in Auto. This is why I don't do testing even in our sparsely populated country neighborhood.

    Normally I use a laptop and MP in the field, but I bought a new tablet and decided to use Tower.

    Run #1: perfect run, smooth flight approx. .75 miles, landed right on target.

    Run #2: changed route a bit, uploaded to FC, did normal checks, good GPS etc.

                 a) armed, start motors,

                 b) switch to Auto, copter takes off, looks ok for a few seconds but does not go to takeoff altitude

                 c) Tower announces "heading toward wp1"

                 d) copter does a small circle then flies in completely wrong direction toward the woods.

                 e) I immediately knew something was very wrong, switched to RTL, no response......copter kept

                     going horizontally in a bee line to the the woods

                 f)  copter quickly went out of sight behind trees, tried to switch to Poshold and pull response

                 g) tried to switch to Stab (no Super Simple) and pull up, no response.

                 h) Tower informs me it is landing (failsafe?) despite attempting to switch into a different mode to pull up into view.

    GCS FS is set for 'continue mission'.

    It did land, or something, right in the dense woods about 100 yards away. We could hear the props trimming the branches. Fortunately we located it rather quickly, with no apparent damage other than one motor mount twisted, props muddy.....nothing broken. The motors had shut down; thank goodness for crash detection!

    Making the landing gear so they would break loose instead of breaking off worked at least.

    I am totally baffled by this as this quadcopter has been my test vehicle and actually the most reliable best flying of the fleet once the Auto Tune issues were resolved. I could have made a mistake with Tower, but can't determine what. It doesn't make sense.  The copter did not RTL when commanded and did not appear to respond to further commands. 

    Attached are log files 3.3 rc7 This copter is using AUAV-X2 FC.

    2015-07-12 20-57-12.bin
    • Developer

      RE the flight modes, the vehicle did switch to RTL but this didn't help because the horizontal position estimate was bad so it continued to fly off.

      A bit later, it refused to enter PosHold because the position estimates had gotten very bad.

      Very soon after it looks like the pilot switched to Land (with pilot controlled roll/pitch) which did work and the vehicle flattened out.  So maybe in the hubub the pilot selected LAND instead of the intended Stabilize.

      Glad your copter wasn't too badly damaged.  We can't fix the compass interference in software but the EKF check will be working for AUAV-X2 boards in -rc8 and that would have caught things before they got out of hand.

      • Thanks Randy.

        I was on vacation last week and of course didn't notice the AUAV-X2 EKF issue until after posting.

        Once it went into Land mode (as the nice lady on Tower told me), it is possible the radio signal was blocked as the woods were very thick because I most definitely attempted to switch into Stab and PosHold. I couldn't see or hear the copter until it morphed into a blender in the trees.

        What is the cause for a bad horizontal position estimate? Hardware malfunction?

        Would MP have warned me before takeoff? It's really odd because this copter has been very reliable.

        • Developer


          I'm pretty sure the compass interference is coming from the power wires or ESCs - at least that's the most common cause.  The compassmot values are there but quite low so I suspect that something has changed since the compassmot was done.

          There's some pre-arm checks that the compasses are consistent, offsets are reasonable, etc but because the motors aren't running we can't see the interference while it's flying.

          • This is why dev input and "crowd sourcing" is so invaluable in figuring out these events! You and Marco may have hit on something.

            I had recently replaced the AUAV case with the latest version using plastic clips. The new version has a box that surrounds the barometer nicely, then I put a thin layer of foam to make sure it is completely covered.

            Come to think of it I did not check for EMI (compassmot not redone) after switching out the case; didn't occur to me to do that as I was more concerned about altitude issues because of the barometer being exposed to air/light. The new case appears to have fixed the altitude drifting.  

            I highly doubt the ESC's are the problem because it's using a HobbyWing Quattro 4-in-1 which is mounted underneath on the bottom of the frame with the wiring nowhere near the FC. There is however the main power wire that runs through the center of the frame underneath the FC, approximately 3/4-1" away. Maybe an extra CF solid plate should be used or raise the FC up higher (not too keen on that.....would have to redo all wiring).

            Odd though that it flew so well for 5+ flights, then anarchy.

            Thanks for your attention to these sometimes overlooked details.

        • Bummer about your crash but at least you found it and it wasn't too bad. Just fyi stab mode is the go to mode in what happened to you. Poshold and RTL both require gps and or compass. If it's a 'fly-away' stab mode with do nothing except keep the copter level which is what you want. Just make sure to give it enough throttle at the same time. If it's beyond a tree line just out of sight go higher until you can see it. At that point yo can get your bearings and fly it home yourself. You probably knew that but just thought I'd post it anyway. 

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