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
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!
the arms are very stiff. however the folding mechanism could be the weak point which allows vibrations to occur.
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.
Be careful with the built in buzzer. It may interfere with the Accels and the compass.
Thanks Leonard, thanks for the massive amount of time you have spent helping me. Also thanks for making or being part of making this great piece of software.
You are right, life goes on. The Quad is built up again and ready for the next flight (hopefully it stops to rain and be too windy soon)!
This time everything is built even better and there is a screw securing the mounts from turning :P
Also thanks to all the other people who helped investigating this crash!
Great people out there!
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 haven't done any tests with the accels running at 4kHz but it keeps coming up in the discussion with Tridge and Paul Riseborough so I think it'll happen at some point in the next couple of months. Both the XRacer and the NAVIO+ have this IMU and hopefully most manufacturers will move to this IMU sooner or later.
It would be great if it could see ahead so to speak so that if there was an abrupt vertical change in the terrain it could regonise the issue and gain altitude a head of time based on it's trajectory.
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/
Props were still immovable after the crash. I tightened them strong enough and there are also locknuts being used. So I guess it was the feather :P
So I make a new post on this because the other one got so large and this is a whole new topic.
In short: I had a flyaway today with the same copter that circle crashed a few days before.
Here is the last post, where a motor mount got twisted and the copter came down: http://diydrones.com/xn/detail/705844:Comment:2137266
Today, I tested a few failure possibilities:
I detatched a prop from one motor and then gave a little throttle while holding the copter in the hands and it would have probably flipped, as it tilted really hard into the direction of the unmounted prop and it would have crashed much harder if one motor or esc had failed in the last crash.
I also tested it with a twisted motor mount while holding and it behaved exactly like in the first crash, so I am pretty sure now that this has happened in the first crash! The sound you hear in the video is possibly the sound of the twisting mount.
I also made a full throttle test while holding down the quad, then while holding it in the air, I made several stability tests.
The copter behaved perfectly in all tests.
Then without changing the setup, I went out and the copter flew fine in loiter for 3 minutes.
After that, I landed. I started again after about 2 minutes. 30 seconds after the takeoff and holding the position perfectly in loiter, the copter began to drift extremely hard in one direction while still holding the height and heading. It didn't react to any control inputs. It happened too fast to try to switch to stabilize.
The GPS reception was perfect!
The copter crashed into a wall and is pretty damaged now. I was pretty lucky that just the copter was damaged and nothing else.
All the tests and finally the crash flight are in the same log, because I didn't disconnect the battery in between.
I had the voltage and current sensor connected this time.
The flyaway starts at ~221000.
As you may understand, my trust in the copter has fainted now.
It behaved perfectly and in the next moment, it just flies away and crashes.
I looked at the logs and didn't find any sensor defect.
What could it be this time?
I can exclude mechanical failures. I flew it at about 2m height and just hovered (just very little and smooth flying around).
I again demand your help.
Thank you in advance.