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


            We can't explain why one shows more clipping than the other I'm afraid but it could be some kind of physical effect of board flexing maybe.

            This log is making us re-think whether the solution we put in place after your previous crash did any good.  That solution was to de-weight the accels that are clipping but in this case things started going wrong even before they began clipping.

            What's unusual about the vibration it is in the horizontal direction.  Normally the vibrations are in the vertical direction presumably caused by the motors and propellers but in this case, it's in the horizontal direction which makes us wonder if something is bumping against the flight controller.

            Some questions:

            1. you don't remember which direction the vehicle leaned in do you?  We have two attitude solutions running and they disagree so it's hard for us to be sure which one to believe.  You helping us break the tie would be good.

            2. Is this a 3DR pixhawk or another manufacturer's board?  We don't mind the source of course but it removes some variables if we know.

            3. how is the flight controller mounted?  Can you provide a picture?

            4. if you have a log of this copter flying AC3.2.1 that'd be cool.

            • Thanks for support. Answers:

              1. Lean to left side, you can see MP log in attach (fly from 70% of length of log)

              2. It is Pixhack. It have anti-vibration plate inside with sensors.

              3. It is on double-sided adhesive tape and attached by buckle (see photo below).

              4. I try to fly today or tomorrow.

              P.S. You write: "That solution was to de-weight the accels that are clipping but in this case things started going wrong even before they began clipping."

              I not very good speak English (as you can see), can you explain what mean "clipping" in this case? It is mean sharp?


              2015-07-27 18-28-58.tlog

              • Developer

                Evgeny, Jesus, Paul, Artem,

                Well, I wouldn't have expected that!  I've heard of the PixHack but did not know it had built in anti-vibration isolated IMU.  It seems like a good idea but in this case at least it's performance is not good.  I'd recommend going back to the more traditional 3M vibration dampening foam.

                Evgeny, we don't actually have a lot of vehicles with this level of vibration.  I was wondering if you could leave it in it's current configuration and test -rc9 when it's out in about a week (or maybe a little less)?  We're going to try one more idea to improve vibration resistance.  After that testing is done, I'd recommend using the 3M foam or something similar.

                • Ok, I leave this frame for testing RC9. And now I assembling new frame same as previous but with anti-vibration platform and try to check in with AC3.3

                  Thanks for support.

              • Those pixhack have been famous AFAIK for their problem with vibration


                • Yes, the original CUAV pixhack has aluminum shell and the silicon padding inside was specifically designed to dampen high frequency vibes. The plastic case version appears to be not made as good as the aluminum and the silicon pad is harder and is of the different shape. 

                  I have used the original CUAV pixhack for one of my clients. It is indeed a quality made piece of hardware with great IMU dampening especially effective against high frequency vibes. After a positive experience with the "real" thing I have erroneously purchased one in a plastic case (didn't pay enough attention) that one went right back to the seller for a full refund. 

                • Yes, it have anti-vibrations palte with sensor, so I can mount it hard on copter and have good level of vibration. But I'm not sure about second IMU unit, it show high level of vibration. 

                  • My bad Eugene, I must be going blind or something, as on the last picture it sure looks to me as plastic case :D. And yes, as a decent gimbal for anything g bigger than a GOPRO costs about $2k AC 3.3's support of storm32 makes it very attractive. 

                  • Igor, yes exist original Pixhack and fake. I use original with aluminium case. But I think original whatever need external anti-vibration platform on big frame.

                    Artem, у меня точно оригинальный, во-первых в аллюминиевом корпусе и фирменной коробке, во-вторых купленный напрямую от продавца с некоторыми доп. шнурками. Я бы тоже летал на 3.2.1, но мне очень нужны фишки от 3.3, в частности снятие текущих углов с подвеса на Шторм32. Программер сказал, что вырезать этот кусок кода из 3.3 и вставить в 3.2.1 очень трудоемко, приходится пилить 3.3, хотя она конечно мягко говоря сыровата.

                  • Artem,

                    I think it would be nice if you give us a brief summary of the conversation in english.

                    As I (maybe false) understood there are two versions of Pixhack, one seems to be good an the other one has the vibes?

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