FW3.1.3 - Switch to Loiter = CRASH! - ArduCopter User Group

FW3.1.3 - Switch to Loiter = CRASH!

Posted by Oliver Volkmann on April 26, 2014 at 3:51am

Copter Specs:

APM 2.6: FW 3.1.3

Frame Type: Quad (X)

Motors: T-motor 4008-18 380kV

Props: APC SlowFly 14x4.7

ESC: Castle Creations Pheonix Edge Lite 50 Amp

LiPo: 6s 6000mAH 30C

Recently upgraded to firmware version 3.1.3 and went out to fly yesterday in moderate winds. The copter has not gone through any AutoTune yet but is flyable in Stabilize and in Altitude Hold (however it is not so smooth in this mode). After noticing that the copter was very unstable in GPS (rolled, pitched and oscillated) when left in position I performed another Magnetometer (Compass) calibration in the field and then flew again.

This flight went as follows: Took off in Stabilize. Switched to Altitude Hold, flew for a few seconds and then switched to loiter where immediately the copter flipped and crashed.

Can anyone tell me what happened here? I would greatly appreciate the help!

Kind regards,

Oliver Volkmann

2014-04-25 16-37-51.log

2014-04-25 16-37-51.log.gpx

2014-04-25 16-37-51.kmz

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crash, loiter

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Replies

- Developer
  
  Randy > Oliver Volkmann April 27, 2014 at 5:32pm
  
  Normally the compass declination values are updated automatically by looking up your GPS location in a table. I don't think the zero declination means something has been corrupted, it's more likely just that there was no GPS lock at the time the declination was written into the log (it's written as soon as the vehicle is armed).
- Alexsey Novik > Oliver Volkmann April 27, 2014 at 9:06am
  
  Change your Mission Planner to older version 1.2.97 works fine
  
  Newer versions lead to corrupt compass declination values
- Waladi > Alexsey Novik April 27, 2014 at 9:08am
  
  +1 for Alexsey solution.
  
  I have almost similar problem with compass and strange behavior in any gps related flight mode.
- Oliver Volkmann > Oliver Volkmann April 26, 2014 at 2:02pm
  
  This is the Pitch vs Pitch In issue I see in Loiter mode.
- Oliver Volkmann > Oliver Volkmann April 26, 2014 at 2:10pm
  
  And here is the other flight log with the Stabilize Pitch and Stabilize Roll values at 2.5. I'm hesitant to increase those back up to where the AutoTune did because of how crazy this beast gets when it is subject to strong inputs either from the remote control or from the wind. I'm very confused as to how to solve this issue when Autotune doesn't seem to get it right itself.
  
  2014-04-26 10-49-57.log
  
  2014-04-26 16-28-39 31.log
- Oliver Volkmann > Oliver Volkmann April 26, 2014 at 2:42pm
  
  Here is my Parameter File:
  
  good flight except gps.param
This reply was deleted.
- Oliver Volkmann April 26, 2014 at 2:15pm
  
  Seems to be the cause. Hard to tell because of the crash damage but I did notice that one of the folding arms of the SteadiDrone QU4D that I am using was loose. Very embarrassing but weird that it happened at the exact moment of switching to loiter. Anyway, repairs have been done and now I've noticed more issues. as noted in my post below.
  
  Thanks to all of you who have tried to come up with some reasoning as to what is going on. Unfortunately, the saga continues!
Jakub April 26, 2014 at 7:46am

GPS was malfunctioning at the end of your flight. Number of satellites went from 11 (which is quite a good number) down to 10 (which should be also good enough number but apparently wasn't) and shortly after that error state followed. So I assume the receiving conditions are not the greatest for your GPS module. Try to lift it above the propellers or further away from other antennas and/or strong current flows on the copter. Seems to me that GPS is on the edge in your case.

Wish you many happy flights anyway. :-)

Jakub
- Oliver Volkmann > Jakub April 26, 2014 at 2:13pm
  
  yeah, it was upside down when I lost the GPS.