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 –


  • Today I test for first time 3.3 rc11, two short flight to test the new controller, with standard params no tune yet and some wind; when I download the logs I find that RTL appears two or tree times but I didn't switched, I was near the copter and no failsafe err appears, I check PWM values and looks well, What can be happened?

    2015-09-22 17-22-20.log

    2015-09-22 17-39-30.log

    • Hi Cala,

      If you look graph "Battery Issues" from the pull down in the log analyser, you can see strange drops in the VOLT reading (It actually goes negative).  VOLT drop whenever there is a spike in THROUT (Maybe a battery issue).  It seems that when both THRIN and VOLT goes low you get the RTL.  It is very short as it seems that once the VOLT go back to normal so does your flight mode.

      What power module are you using?  Is it 6S? 

      I might be wrong but are you sure that you are not reading CURR as VOLT and VOLT as CURR?  You volt values seem more like current readings (Goes up and down with THR) and the CURR values look more like battery voltage (Starts high and decreases over time).

      When VOLT goes low but THRIN is high you do not seem to get the RTL.  I might be wong but it seems to be the only common thing I could see.

      I don't think that you are actually getting a voltage drop but you power module is reporting a bogus value.

      I think you can change the pins in the config to swap these around.

      Also, it seems that the first part of your flight is before the EKF is completely happy.

      The latest MP has "ekf VEL tune" in the graph option pull downs.  If you look at this you can clearly see when the velocity innovations  IVE, IVN, IVD start.

      I have been trying two different ways to avoid this:

      1: Wait until I can arm with the Fence enabled

      2: Arming in Poshold. (I usually take off and land in STAB but use this to check)

      I think that either method requires both a good 3D GPS lock but also waits for the EKF to be happy with position and velocity comparisons between the IMU and GPS.  Not sure if it is the Gyro's settling or the GPS velocities taking time to match up.

      I have also noticed that if I  land and take off without disarming the EKF noise is a bit higher.  I think it may be due to GPS velocity measurements when the frame is landed (ie motionless) but GPS still registers small position shifts. 

      This does not seem to cause flight issues but I think it does affect things such as the origin setting.  I have been playing it safe by making sure that the EKF is completely happy before taking off.  It take a couple of minutes first time round but after that it is almost immeadiate.

      Hope that helps!!

      • Many thank's Alex, It's possible that pins are changed, I have an old 3DR Pmodule 3-4S and didn't check that, I have to invert nearly all when I change the APM 2,5 to Pixhawk (chinnese) I have the 6s PM that's arrive with the Pix, I'm going to change pins and if doesn't work I change the PM, many thank's to discover, I didn't take care of curr because I had an external alarm reading batt and looks good when I land so I'm not going to discover the issue for my oun.

        Thank's for the tips, arming in Poshold it's a good idea, I almost time fly in pos hold so check looks interesting for me.

  • Does anyone know why Rate P and I are always the same when autotuning in 3.3?  Seems a bit strange.  Trying to sort out why my unit is shaking on takeoff, but flies well otherwise.  Maybe not related, but still seems odd P and I are always the same.  

    • Developer

      Hi Shaun, 

      This is because autotune sets them to be equal. This is based on the time constant the average pilot expects to see.

      • Am I the only one that didn't know that?  

  • RC11 flies very well. I had frequent EKF issues, all resolved now. Thank you!


    I have not seen any info regarding DO_MOUNT_CONTROL other than mentioning it in the wiki. I have wanted to use this for some time now, so I thought I would post a video showing my results. I did not spend a lot of time planning the mission and its not the greatest video, but maybe it will help someone. I am flying a stock IRIS+ with a tarot 2d gimbal, so pitch will be the only variable. In mission planner my gimbal is restricted to move between 0 deg and -90 deg.  If using a different gimbal, check the gimbal set up page to know the limits for this command. I initially tried a pitch setting of 20, and since that was out of the range of 0 to -90, nothing happened. When I figured out pitching down should be a negative number, it worked great. At the first waypoint the camera goes to -20 deg, followed by -25, -30, -35, and -40. I included the waypoint file is case anyone wanted details.

    I'll be using -30. Here's a large road project near me. This video ends showing a transition from DO_MOUNT command to ROI and back to DO_MOUNT.

    mount test.txt

    • Developer

      Thanks for testing, nice video!

This reply was deleted.


DIY Robocars via Twitter
RT @DanielChiaJH: @a1k0n @diyrobocars @circuitlaunch And here's the final showdown! Video courtesy of @chr1sa I think I was a little faste…
8 hours ago
DIY Robocars via Twitter
RT @DanielChiaJH: @a1k0n @armand_dpl @SmallpixelCar @diyrobocars @circuitlaunch I use @foxglovedev Foxglove Studio for my visualization nee…
8 hours ago
DIY Robocars via Twitter
8 hours ago
DIY Robocars via Twitter
RT @a1k0n: @DanielChiaJH @diyrobocars @circuitlaunch Here's my car's view of that race. About 8.4 second lap times for laps 2 and 3... both…
DIY Robocars via Twitter
RT @DanielChiaJH: Great racing against @a1k0n today at @diyrobocars! Pretty cool to both break sun-9s at the track today I think I got very…
DIY Robocars via Twitter
Broadcasting the @circuitlaunch race live now at Races begin around 2:00pm PT
DIY Robocars via Twitter
RT @a1k0n: ran a huge number of hyperparameter tuning experiments yesterday; now I can train a new policy, far with better quality, in 15 m…
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…
Sep 26
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…
Sep 26
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…
Sep 26
DIY Robocars via Twitter
Sep 24
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…
Sep 24
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…
Sep 24
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…
Sep 23
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