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'm with you on that Paul. With three slightly different capacity packs I can fly with on any given day, including one after the other, I need to have Voltage Only triggering Land or RTL if I want it to. 

              • So, no one can offer neither advice nor explanation of what may be going on with this feature? I tried all combination again today, made sure in the voltage sensor screen it makes an alert, I saw alert on the MP screen for low voltage, but still no sign of any attempt to initiate a failsafe by voltage level.

                What is the deal with it?

                • Paul I did flight tonight and flew long enough to get a battery voltage failsafe trigger, so it's working for me. This was at about 50% of set capacity (using older packs that never get near capacity now)...

                  • Martin, what do you mean by '50% set capacity' ?

                    What did you set into parameters? Did you put in a specific voltage level for failsafe to initiate or a percentage of a battery capacity? What condition triggered your failsafe event - capacity estimate or an actual voltage level reading?

            • Little off topic, but Paul, isn't 13.9V (3.475 per cell) a little too low?

              I almost always finish my flight around 15V (3.75 per cell)

              • I even go for 3.3V/cell under load. You are perfectly safe as long as voltage/cell does not drop eveb for a short period below 3V - thats typically the threshold when permanent damage will occur.

                • I go down to 3.3v per cell as well. It is perfectly fine to me under load. Going 3.5v per cell is also okay but anything more than that is a bit too conservative to me.

                  Obviously when I give my answer I consider one will land soon after the 3.3v per cell is triggered. If you plan on flying for minutes or are far away from home then you will definitely need to consider higher voltage values here. 

                  • If anybody got 3.3rc5 to initiate failsafe RTL by a specified voltage level - pls share a screenshot of what you have configured for this to work.

                    As of voltage level - 3.3V asks for an almost immediate landing, when I did set it to 13.9V in failsafe it would still fly until it drops to 13.8v, then in a 20sec or so it would initiate RTL and by arrival to the spot from 100m or so it would be at 13.3-13.5V and it worked for me fine, all in 3.2 firmware. I have no clue why all the same stuff now does not work, I just looked at my APM how it was set in there. Voltage level set =13.9, reserved mAh = 0. Odd stuff.  

                    Should I just set 'reserved mah' parameter to any !=0 value now for whole thing to work? is it that simple?


              • 3702907477?profile=originalI am not sure. Do you use 6S power? I am not sue what would you gain if you stop flight at 15V on 4S power. It is probably good for batteries but on my batteries from 15V to 14V it is several minutes of flight.

                Look at the battery discharge graph from this test where failsafe did not occur and I waited until the end of power. Decide for yourself how to configure the system.

                • Received wisdom is 3.7v+ at rest, 3.5v+ under load or 20% capacity left. I set my failsafe at 14.2v. 3.75v under load is going to leave an extra 20% or so of the battery unused.

                  I'm interested in your Err-RADIO-2. What caused this? I am suffering with these at the moment. I'm assuming it's my RX, but its happening regularly at the end of my second battery - 3 times in a row now, which seems weird.

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