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!

You need to be a member of diydrones to add comments!

Join diydrones

Email me when people reply –


  • So did some experimentation with batteries on my QAV250 because of that youtube clip. Turns out the wire end of a LiPo has much more interference than the blunt end, even if the wires are close together or twisted together (I know the wires cause interference but it's interesting that its so pronounced). If I mount the battery with the wires near the compass but folded back I get 80% interference, if I turn the battery end over end I get 20% interference, even though the battery itself is in the same position. I have subsequently resoldered all the XT60's on my small lipos so that they have short tails so that I can mount them with the wires pointing out the end of the quad.

    I haven't flown yet, but I'm pretty hopeful!

  • I'm not sure if this is the place to post a request for the next release, but it would've been nice to add a rc overide for the mount when dealing with ROI. Sometimes Gmap overlay is way off, in my area is like 5-10 meters offset, many times doing auto missions with ROI I have to move the ROI around in MP until I find the right spot.( I'm using ST32 gimbal, all angles match in the gimbal controller and FMU). Also if one is to change his/her mind in the middle of a mission and wants to take manual control of the gimbal is kind of impossible until the mission finishes. A workaround I've found, is to briefly change modes back and forth. It would've been even cooler if we can set ROI in flight, pointing a camera at a desired target and set ROI with a switch, kind of like save WP option. To whom may be interested, regarding my crash posted here few pages back, I have found no mechanical issues, I've flown it since then with 3.2, I mean realy beating the hell out of it and it performed flawlessly, in the process I also recovered the lost plane after almost a week, intact, only with a puffed 5A lipo. Speaking of finding the needle in the haystack, I have covered 2 acre of sugarcane field until I spot it. Just for fun I'll upload just the frame where I have found it after examining almost 1 hour of footage. I'll make a story about this, it was such an adventure. The sugarcane is about 3.5-4 m tall, I have flown at 20m with a 90 degree fov lens. The plane it white 1.5m span, see if you can spot it. This is the only frame where is the most visible.


    • Took a few seconds ....... about 20% right of the left margin and about 25% down?

      I can imagine you going nuts looking at hours of that sugar cane!

      One went on a full sized sailplane retrieve where the guy had landed in a sunflower crop field. The sunflowers were ripe so the field so looked black like a nice inviting ploughed field from above. It was only when he was committed that the pilot saw it was a tall crop ( also about 2.5 to 3m tall )

      Plonked it in and sank to ground level. We drove around the perimeter of that particular field ( several hundred acres ) more than once. Aircraft was only 50m in from a boundary but totally invisible. :) We found the pilot at a farmhouse eventually. He'd tied a jacket to the fence near the aircraft to mark the area and even then you could walk 15m away and not see a 15m wingspan bright white full sized aircraft!

      We took several buckets of dry sunflower seeds out of the fuselage when we got back to the airfield!

      This was all 40 years ago, if we'd had a UAV it would have been a lot quicker to find it! :)

  • Hi, would anyone be able to provide some assistance here?

    Built my second machine and I haven't gotten it quite right as yet. Its been having and inconsistent yaw issue, where it yaws uncontrollably. Sometimes it responds to input, sometimes not. One day itl be fine, the next, not. I've torn everything down and tested almost everything i can think of. Today i accidentally armed and took off in loiter, but the yaw issue was still there, surprisingly it seemed like loiter kept in from spinning off into a random direction.  I can list each component if necessary, Attached are two logs, 

    7.bin is where it flew mostly fine.

    15.bin is the most recent where the uncontrollable yaw is happening again

    Dropbox - Link not found
    Dropbox is a free service that lets you bring your photos, docs, and videos anywhere and share them easily. Never email yourself a file again!
  • not sure I understand this parameter setting for EKF_FALLBACK, how can EKF fallback to itself? or am I misunderstanding (am sure I am!)  

    whats the basis for using either option? would love to hear from one of the devs


    • Developer


      This parameter is ignored in Copter but is used in Plane.  We could probably hide it but in any case, in Plane they allow the user to choose whether to use DCM or EKF but for Copter that's never a good choice because DCM can't do the position accuracy we need for RTL, Loiter, etc.  There is one exception in that Copter will fall back to DCM if the EKF has NaNs appear within it.  This should never happen because we should have the necessary checks in the code to stop it from happening.. but the fall back is there just in case.

  • Developer

    I made a mistake during the release process yesterday and TradHeli has accidentally been upgrade to Copter-3.3.  The testing for TradHeli isn't complete so we will revert it to Copter-3.2.1 asap.  Any TradHeli users out there reading this should not upgrade to Copter-3.3.

    Multicopter users should not be alarmed, this is a TradHeli specific warning.

This reply was deleted.


DIY Robocars via Twitter
RT @a1k0n: Did I get rid of hand-tuned parameters? Yes. Am I still hand-tuning more parameters? Also yes. I have a few knobs to address the…
DIY Robocars via Twitter
RT @a1k0n: I'm not going to spoil it, but (after charging the battery) this works way better than it has any right to. The car is now faste…
DIY Robocars via Twitter
RT @a1k0n: Decided to just see what happens if I run the sim-trained neural net on the car, with some safety rails around max throttle slew…
DIY Robocars via Twitter
DIY Robocars via Twitter
RT @SmallpixelCar: @a1k0n @diyrobocars I learned from this. This is my speed profile. Looks like I am too conservative on the right side of…
DIY Robocars via Twitter
RT @a1k0n: @SmallpixelCar @diyrobocars Dot color is speed; brighter is faster. Yeah, it has less room to explore in the tighter part, and t…
DIY Robocars via Twitter
RT @a1k0n: I'm gonna try to do proper offline reinforcement learning for @diyrobocars and throw away all my manual parameter tuning for the…
DIY Robocars via Twitter
RT @circuitlaunch: DIY Robocars & Brazilian BBQ - Sat 10/1. Our track combines hairpin curves with an intersection for max danger. Take tha…
Sep 22
DIY Robocars via Twitter
RT @SmallpixelCar: Had an great test today on @RAMS_RC_Club track. However the car starts to drift at 40mph. Some experts recommended to ch…
Sep 11
DIY Robocars via Twitter
RT @gclue_akira: 世界最速 チームtamiyaのaiカー
Sep 10
DIY Robocars via Twitter
RT @DanielChiaJH: Always a good time working on my @diyrobocars car at @circuitlaunch. Still got some work to do if I’m to beat @a1k0n howe…
Sep 10
DIY Robocars via Twitter
RT @SmallpixelCar: My new speed profile for @RAMS_RC_Club track
Sep 10
DIY Robocars via Twitter
RT @SmallpixelCar: Practiced at @RAMS_RC_Club today with my new @ARRMARC car
Aug 28
DIY Robocars via Twitter
Aug 24
DIY Robocars via Twitter
RT @gclue_akira: 柏の葉で走行させてるjetracerの中身 #instantNeRF #jetracer
Jul 4
DIY Robocars via Twitter
Cool web-based self-driving simulator. Click save when the AI does the right thing
Jul 4