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my first big flight away

Posted by Max Patissier on December 14, 2014 at 6:52am

Hi to all

well, custom H alu frame, APM mini firmware 3.2 - GPS Ublox 6h, Qbrain 4x25, moteur Ipower 850Kv.

I start the quad this morming with auto mission 800 m. Wait for 7 satelites - I usualy get 8/9 satelites in our open field,

Started with Alt Hold, seems all good and when I engaged Auto, the quad went 90° and flight away.

I was unable to get it back, no responding to the RC. Thank to telemetry I found it back, very close to a lake.

The log send EKF error, fail safe EKF.... but the EKF_CHECK_THRESH = 0, so I understand that EKF is not acting.

One point very surprising : Z vibration get worst and worst. Never see this. I usually get very low vibrations.

Thank you for your advices !

Log attached

2014-12-14 11-10-14.log

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apm, away, flight, mini

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Replies

Richard Kennedy December 17, 2014 at 4:32am

Looks like your hdop was around 3 when you hit auto. That's not very good.

Looks like the VCC [ which I think is the voltage feeding the controller from your BEC ] dropped to 3.8 or so a couple of times. I'm pretty sure it should be around 5. I guess your not using a power module just a BEC? The the log seems to be corrupted I can't even see rc in or rc out. What kind of radio and receiver are you using? Anyway I am not real good at reading logs just a couple things I notice. Just for the heck of it you might want to change and or double check all your wiring connectors. I had an issue once it acted badly sometimes other times not. Turns one of the 4 wires from the mag was pulling out of the connector. I think I'd consider a gps with a bigger antenna that might help with the sat count and hdop. I've had good luck with this [ this is for the pixhawk 6pos connection apm version uses a 5 which they sell as well ] http://hobbyking.com/hobbyking/store/%5F%5F55558%5F%5FUblox%5FNeo%5...

But again... I'm no expert reading logs. Good luck.
- Max Patissier > Richard Kennedy December 17, 2014 at 4:47am
  
  I am using BEC from Qbrain 4x1 - I prefer that as separate UBEC because less cables mean less problems.
  
  I think the logs were corrupted because of the fall.
  
  I am using orange TX and RX
  
  Anyway, thank you for you rtime
  - Richard Kennedy > Max Patissier December 17, 2014 at 5:05am
    
    Just FYI that's the same 4 in 1 esc I use. Your right less wires... nice. Hope you figure out the problem.
    
    ps send some of that warn air up to North America please :]
    - Max Patissier > Richard Kennedy December 17, 2014 at 5:08am
      
      the fact is that we have currently a nice wind coming from south -> 24°c / 28° for tomorrow.... a pleasure to fly
Max Patissier December 15, 2014 at 6:24am

I try to use kml to understand this flyaway but I cannot understand why the quad went 90° north as soon as I engaged auto and why it didn't response to LAND mode. It was 50 meters from me.
- Max Patissier > Max Patissier December 15, 2014 at 8:51am
  
  https://www.dropbox.com/s/ss7lc79lbin2c38/flyaway.PNG?dl=0
Max Patissier December 15, 2014 at 4:34am
Randy, I just saw this :

https://groups.google.com/forum/#!topic/drones-discuss/rR5CChipB6I

So, I have 2 questions :
- is EKF out if we are using apm 2.6 ? ArduCopter 3.2 adds a DCM heading check and an EKF (Extended Kalman Filter – Pixhawk only) check to catch flyaways caused by a bad heading estimate.
- I put EKF_CHECK_THRESH = 0 - is it dangerous ?
The fact is that I get in 2 days 2 majors incidents with 2 differents quads in a auto mission. One trying dronies mission with droidplanner - the quad went 180° opposite, right to a tree - and this flyaway with quad going 90° as soon as I engaged auto. And out of control.

Thank you for your help.
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- Rob_Lefebvre > Max Patissier December 15, 2014 at 10:55pm
  
  No, there is no EKF for APM 2.6. I think what you're seeing is more of an error in the log analysis program. Those errors #16 and 17 should be labelled as INAV errors for APM2.