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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      • As per wiki instructions( ) there is 3 ways that you can set radio failsafe.

        Low-Throttle method

        No signal method

        Receiver method

        I'm referring to the 3 option. It was working on AC3.1.5 and is not working on 3.2.1

        Same thing for the failsafe on AUX channels 1 to 6, on ac3.1.5 I set my camera to be pointing to a specific position in case of an loss of signal in my receiver and it's not working anymore with 3.2.1.

        I have done a detailed report of the problem here about one month ago. For me it was very useful and I'm said that it's not working anymore. I didn't see any info in the AC3.2.1 release description saying that it would be disable and besides, receiver failsafe instructions are still in the wiki.

        Thanks for your reply.

        • I had problems with the receiver method in 3.1 and 3.2. Depending on where my mode switch was it would act differently. Doesn't make sense but that's what it did. No signal method is what I prefer because it will continue in RTL even if the RX regains signal. But why it worked for you in 3.1.5 but not 3.2.1 is a mystery. 

          • Thanks for your reply...

            I tried in 3 different pixhawk board, and in all of them receiver failsafe would work in ac3.1.5 but not in the ac3.2.1, so I understand that it was a firmware problem.

            Anyway, is there anyone that could confirm that the receiver failsafe method should be working in AC3.3?

            Thanks in advance.

  • Developer

    Copter-3.3-rc11 is now available through the mission planner’s beta firmwares link.

    This has just one change from –rc10, instead of saying “Waiting for 3D Fix” during pre-arm it gives a detailed reason like “PreArm: Need 6 sats (have 5)”.

    We're aiming to do a soft release of Copter-3.3 probably this weekend.  So that will just be renaming -rc11 to Copter-3.3 and asking the general community to upgrade to 3.3 and report any issue into the APM Forum.  We will let that go on for a couple of weeks and if nothing scary comes up we will replace 3.2.1 with 3.3 as the official, default for Pixhawk and other high CPU boards (APM2 will remain at AC3.2.1).

    Thanks all!

    • A few points.

      Can't provide bin files and can't figure out why, but that's another issue.

      This TLOG has some of the tests I managed to do after lunch, and there's something weird with FS_THR_VALUE that I had set for 960 and only after disabling the Radio Failsafe I was able to fly. Radio Calibration done.

      Radio system is DSMX and is set to bring CH3 to 930 with radio off and I can see it on the Failsafes screen.

      First impressions without auto tuning is a flawless flight but with the windy conditions I had AltHold was behaving reasonably well, PosHold was unable to get a fixed position, and Rob's Break mode was absolutely fantastic, because it kept the small quad absolutely static on the spot.

      Won't test more, until I can figure out what's wrong with the damn FS_THR_VALUE, because I don't want to fly very far without Radio Failsafe.

      ps: As a side note. I hope Paul is able to offer us all some aluminum made cars, because at 2m distance from my car (Honda) Compass Variance of the EKF goes nuts......

      now to see why I don't have logs on the damn microsd, and no warnings from the card....

      • Developer

        Thanks for testing.

        If PosHold was unable to hold a fixed position, but Brake mode worked then it means that the issue is not a GPS quality or EKF position estimate issue.  It's most likely that the radio trims are slightly off and so PosHold thinks that you're supplying input.

        Copter-3.4 will automatically clear out the binary log files if the SD card fills up but that's not in AC3.3 (nor AC3.2.1) so it just requires some manual effort now and then to clear off the files.  The files are bigger than they use to be though so perhaps the SD cards are filling up faster than they would have with AC3.2.1.

        • Thanks Randy,

          I looked at the radio logs, and it doesn't seem to be anything related to radio inputs, as it can also be seen from the TLOGs.

          My biggest issue now is to sort out the THR_VALUE for the failsafe....

      • Ah,

        something else Randy.

        Bunny hopping on land still here :)

        • Developer


          Really we need to see logs but I strongly suspect this is a ground-effect-on-baro issue.  The Solo suffers from the same thing and you can see how it lands near the end of this video.  Solo-master has a work-around for this that we may add to Copter-3.4 but we need to review it and ensure it doesn't mess things up for other users.  If this is indeed the issue, then I think it will show up clearly as baro movement during landing and a physical change to the frame is probably the only viable solution in the short-term.

          • Just a positive reflection:

            Two examples with Land (last 7 seconds of the Video).



            No bouncing @ all. Btw., all Settings @ Quad Default , no autotune. Since I do a lot of flights at 1-2 m height, I don´t believe in ground effect issues.

            I´m always using LAND (coming usually from PosHold) and it works perfectly with -rc10,-rc11 with AUAV-X2 ,Pixhack (with internal damping) @F450 and the Pixhawk Lite cheapo @ Mini Drones 500mm Carbon Frame.

            PS: What I like about it,that the throttle hasn´t to be moved down

            Thanks a lot for the good work !

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