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
Richard,
Boat mode isn't included in Copter-3.3.2. If you're feeling brave you can load up "master" though you can go to MP's Install Firmware page and press "Ctrl-Q" to get V3.4-dev. Many of the devs fly master but please remember it is broken from time to time.
I was referring to this but I guess it wasn't right... the ct.-Q way I didn't know about thanks! http://firmware.diydrones.com/Copter/latest/PX4-octa/
Hi Dave,
This is an unusual log. There is no obvious motor sync issue or any sign pointing to one motor being lost. The closest to this I can see is that Motor 1 appears to be working a little harder than the rest but this is probably just due to an offset CG or that motor having a slightly lower kv than the rest or something similar.
What this looks like to me is one of your motors has rotated during the full throttle burst. This has then caused a yaw that the controllers are fighting by dropping motors 3 and 4 to minimum. The thing that makes me think that this is the case is that motors 1 and 2 are almost equal suggesting that neither one is bad.
If you have a single motor out situation then you normally see loss of roll and pitch control with a single motor going to maximum.
When you looked over the copter after the crash was any of the motor mounts able to rotate on the arms or needing to be straightened. There is a 1 in 4 chance the motor that rotated is also the one that broke in the crash.
Does any of this match what you saw in your copter as you fixed it?
Hi Dave,
So this has got me puzzled. We have Motor 1 going a little high for a moment during the full throttle burst but nothing too major. Maybe enough to suggest that the problem may have started there.
We see the negative yaw rate error starts we also see a small positive roll and negative pitch angle error appear and go away. This initial deviation suggests a loss of lift from motor 1.
This is where I would normally expect to see all other motors go low and the copter flip roll positive and pitch negative with a slight negative yaw. However this isn't what happens (obviously).
So the copter does something very strange at this point, it hardly loses roll and pitch control at all and instead starts to spin in yaw (negative) with both motor 1 and 2 high and 3 and 4 low. This is very unusual because motors 1 and 2 have very similar outputs and they stay that way all the way down.
Looking at the logs I see two possible causes of this combination of events.
1. We have partial failure of lift on both 1 and 2. This may be sync issues, loose props, interference on the esc signal line, ice build up on the props (thanks Martin)..... Any other ideas.....
2. One of the arms rotated in flight. Because motors 1 and 2 have the same output and we expect to see a lost of lift from a rotated arm, that would suggest motor 3 (being higher than 4). You have already said this doesn't look like the problem unless the cold allowed them to move. However, you should have been able to see this on the copter after it landed.
What arm broke?
This really has me stumped....
Looking at the video it looks like there is some serious vibration as you go full throttle and the initial yaw rotation looks almost violent and there appears to be a shock go through the frame just as it happens. Looking at the vibration logs you can clearly see this too. Vibrations steadily increase from the moment you go full throttle as the motors spool up (you can hear this on the video). Then BAM there is a massive amount of vibration just as you loose yaw control. You are getting clipping in the accelerometers meaning you are hitting 16g. Your climb rate reaches 3g so your copter is putting some power down during the climb. So this is definitely pointing to a serious mechanical problem. So maybe the person suggesting your arm broke in flight rather than in the impact was correct. It may not have been a full break and instead twisted partially in place causing the yaw rotation.
Any more information you can think of??
Forgive me if this was already discussed pages back but... could a prop have come only partially loose? It could cause high vibration and noise.
Another off the wall possibility is perhaps one prop caught something like a feather that of course fell off on impact so you never knew it. LOL yea I know..... suuuuuure that's it.
I will have a look as soon as I get home.
And sorry for the capital letters.
:)
Ok. But given the sudden chaos in the video (and 200 feet away!), your eyes work much faster than mine.
George
Hi Dave,
If one of the arms was rotated by 5 degrees after the crash then that fits all the symptoms. I suspect the sound you hear is the arm rotating under the large vibration forces I see in the logs. 5 degrees may not have been enough for me to see the lost lift from that motor.
This may have been made possible because of the cold air letting things move just a little easier than they do when everything is back up to temperature.
You are in good company with that crash, Marco had a motor rotate 90 degrees on a hex. Thankfully arducopter kept is stabilized nicely an he was able to land it without damage.
I think you are safe to assume this is the case and give things another try.
Here's a useful video on why motor mounts fail roughly where yours failed:
https://www.youtube.com/watch?v=57XZW0eYfpc
(you can skip the first 5:50 entirely)
Motor mount 'stealth' fatigue is a serious hazard.
George
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