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!
Replies
according to what I have read in the EKF settings, you may increase the importance of the GPS over the Baro alt correct ?
Could that be preventing it, if nothing obvious can be found in the hardware section... I do use vibration damping which is more solid than the original 3D damping, so I may need to go back to this softer stuff...
Currently the PixHawk is close to hard bolted to the frame..
Thanks again !
Looks like high vibration levels. Hopefully we will have some real-time display of this in the ground stations in the near future. For now it's only visible in the dataflash logs but they are very clearly too high.
I am however wondering why as the same platform has been flying fine for quite some time, i.e from 3.21 onwards....
At the first part of the flight when I still was in loiter the vibes are fine, it's as soon as it is gaing height in Auto it starts, but isn't this obvious as you are moving up fast ?
I.e are we looking at the result of the movement here ?
Erik,
The vibration levels are really quite high even at the beginning. The AC3.2.1 vs AC3.3 resistance to vibration is a good question - so the biggest difference from AC321 vs AC33 is we've replaced the 2nd-order-complementary-filter (aka InertialNav) with the EKF. We were expecting that that would improve resistance to vibration but in fact, it may not. It may even be worse which would be a bit of a sad result. PaulR (creator of the EKF) has started on the "New Maths" which is a large-ish change to improve EKF's robustness (i.e. bad vibes, bad sensor data) but that won't come until AC34.
AC33-rc9 will have one final change directly related to the EKF's vibration resistance, it's going to do a better job of picking the IMU with lower noise. Hopefully that will help.
Don't get me wrong I do like the progress a.k.a EKF, but I do see rather inconsistent behaviour between flights..., in RC7 I had clipping up too 3000 and higher, without any strange side effect...
I have never seen any EKF errors in my logs...
Suddenly now I get up to 100 (VIBS) and it is acting like it may jump up and down anytime... which I do not understand.., as the hardware didn't change at all.
I'll also do a compare between Params RC7 and RC8 to see what did change between both versions after initial download, maybe something has changed there ?
In my second flight yesterday I did reduce VEL_Z_P from 5 to 3 and in AltHold it was holding altitude a little better I.e without the engine variance in sound..., not sure if that can be related to this or not, but it was flying smoother as before...
I agree with what Andy says of course.
I'll also add that -rc8 had an attempt at improving the EKF's ability to deal with high vibration by pick the IMU that was clipping less. We've found that didn't improve resistance to high vibrations though (as we saw from Evgeny's on-going problems) so -rc9 will use a different method which checks the noise on each IMU instead of the level of clipping.
I have zero clipping on my 3DR X4. Any clipping is bad IMO, I don't think you can ignore it as it means that the sensors are essentially lying to the EKF.
Finally today I was in outside flying just for fun and not for work.
But...
I had 3 fly-away in a row. During Auto-Tune mode.
AC3.3 rc8.
I had recovered my copter by switching in stabilize mode, and after switch I landed.
I ca not undestand why the fly-away start.
At the first tought I thinked that could be the multistar battery.
Since I'm using 10C batteries.
Now I'am not so sure that is battery fault.
Now I think that this is the problem:
It seems that when it switch to AUTOLAND mode due to battery failsafe, it start to flyaway. But why?
Of course that's what I think now.
I'am not sure.
Attached 2 logs that show two of the three fly-away.
5.BIN
4.BIN
Andrea,
Thanks for testing!
So what happened is the battery failsafe triggered a GPS-controlled-LAND but it was able to to control it's velocity probably because of a bad heading. It looks like compassmot has been run on the vehicle but it's throttle based instead of current based. The throttle-based compassmot is not very reliable because the interference is really related to current and throttle's relationship to current is not linear. I've actually been considering removing the throttle-based compassmot.
The MAG messages are not present in the log which means I cannot directly check the interference level. If you could set the LOG_BITMASK to "NearlyAll" that would be good for future analysis.
By the way, as a minor point, I wouldn't personally call this a "flyaway". I think a "flyaway" is when the vehicle flies off out-of-control and out of the pilot's view. In this case the vehicle was indeed out of control for a short-time but through some good piloting skills you re-took control before it got even 10m away.
Hi Randy. I always follow your posts and I have noticed that the idea of removing throttle-based compassmot has been with you for quite some time. I think you should go ahead and eliminate it. I have always used only two options: either I just fly without calibration or make a good current sensor calibration and then run compassmot.
Throttle based compassmot is just a problem wainting to happen specially since novice users think is might be as good as the other option but with less work.
Just my two cents!
Keep up with the good work
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