Hello,
I experienced something extremely dangerous with my quad. I flew for +-6min, mostly in loiter mode. Then I let it hover at about 2m from the ground and suddently it goes full power in the air!! It happened 2 times and the second time it didn't react to changing modes and sticks. Luckily i was alone on the field. At about 300m one of the propellers broke and it crashed (fortunately).
I was hoping that someone could look at my logs? I was really really scared and I am still.
I hope someone can help me that would be awesome!
Thank You.
Max
Replies
Hi Guy's I just had a similar issue but I'm no expert - would someone be able to look at my logs to see if it's a similar issue.
I was flying ok for about 30 seconds just hovering testing it out and then switched into loiter then about 10 seconds later it just shot up with no stick input. - tried to regain control and didnt really regain much control before an expensive crash.
Any help is greatly appreciated
17.BIN
Hey,
I'm not an expert either but it seems that we have the same problem! I reviewed your log and it shows that you have a lot of vibrations too: Test:
IMU Mismatch = WARN - Check vibration or accelerometer calibration. (Mismatch: 1.09, WARN: 0.75, FAIL: 1.50)
The rest of your logs seem to be pretty good:
Test: Autotune = UNKNOWN - No ATUN log data
Test: Balance/Twist = GOOD -
Test: Brownout = GOOD -
Test: Compass = GOOD - mag_field interference within limits (17.47%)
Max mag field length (564.20) > recommended (550.00)
Test: Dupe Log Data = GOOD -
Test: Empty = GOOD -
Test: Event/Failsafe = GOOD -
Test: GPS = GOOD -
Test: IMU Mismatch = WARN - Check vibration or accelerometer calibration. (Mismatch: 1.09, WARN: 0.75, FAIL: 1.50)
Test: Parameters = GOOD -
Test: PM = FAIL - 5 slow loop lines found, max 10.13% on line 8020
Test: Pitch/Roll = GOOD -
Test: Thrust = GOOD -
Test: VCC = GOOD -
This is a clone from Hobbyking, do you think it has something to do with them? Should i stop using it? What about the voltage, doesn't that look like a brownout?
This was my 57th flight with this controller according to the logs, it flew perfectly fine until then :( and suddently...
Thanks so much for your help!!!! Waiting for your answers hehe :D
Just to make things clear:
In your opinion this loss of control happend mostly because of vibrations?
If you had stabilize mode you could have switched to that and brought the throttle lower to have the quad descend.
Hope that helped :-)
Well it fell 300m down because 1) a prop broke OR 2) the little thing (don't know how it's called in english) which holds the shaft of the motor snapped away, because the top of the motor was found 20m away from the copter...
Esc's seem to be fine. There was a "baro fail", could that also have let to this?
Thanks so much for your help!
I wrote an instructable on changing motor shafts. Do you mean this part http://www.instructables.com/file/FY6W7UFHFSHUXHU circlip?
You can probably factory reset and recalibrate with a new motor, if that what is broken.
it ranges between 4.51v and 5.1v which is acceptable. But the dip would also point to excessive power consumption and you can see the amps rise to maximum as it thinks it needs full throttle to stay aloft. The voltage sags from 21V to 15.2V and lower.
These are symptoms of the vibrations. i.e. lots of vibrations makes the copter think it needs more thrust, more current, more vibrations etc...
Vibrations are because of mechanical failure, it could just have been the prop breaking or something else.
Cannot really say more than that really. Did you find anything wrong with the motors post crash, or ESCs?
see http://copter.ardupilot.com/wiki/common-diagnosing-problems-using-l...
You are about 5m of the ground in Alt-Hold, then Loiter. Then at about count 36600 the AccZ vibrations goes nuts, and the quad rises to 150m. As you notice the issue, you cut the throttle, but it still rising. You switch between Loiter >> alt_hold >> Loiter.alt_hold >> Loter and you regain control and it stop rising, but throttle is at zero, so it start to descend at a fixed speed. You switch to RTL, then when at 50m you go to loiter. Everything starts to behave like normal again. you are in loiter. NOTE: Keep throttle at 50% for Alt_hold/Loiter/Pos_Hold mods to keep altitude constant (don't use 0% unless you intended to stop flying!)
Then the graph at 73000 has a AccZ blimp, and again at 75000 and the second event happens at 76300. AccZ starts to go crazy and the copter rises to it 300m destination. You cut the throttle way before that, but it doesn't respond. AccZ is now 'off the chart'
Each blip of AccZ started when you raised the throttle. see bright green line throttle-in matches the rise in AccZ
I'd bet my money on this being mechanical fault, and the frequency of the vibrations started bad with higher throttle requests. To the point that is got so bad, that it just lost control.
Switching to stabilize would have stopped the copter, but with throttle at zero, it would have dropped out of the sky.
Hope that helps :)
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