Thr IN vs Thr OUT exponential deviation

Hi Guys

Had a crash today with my quad, at first it seemed like just a motor failure but after analyzing the logs it seems there is more to it.

Just after the line 13500 (Stabilize) the crash occurs, as you can see ThrOUT (Red) starts to deviate from ThrIN exponentially for no reason that i can see. The blue line is Baro which drops off sharply just after. It seems that something caused the ThrOUT to jump quickly and i think this caused one of my ESC's or motors to cut out causing the crash. The quad was very heavy as i was trying out two batteries in parallel and it was quite a hot day. Motors were very hot after the flight!

When it started falling i cut the throttle as can be seen. When it was on the ground i accidentally switched off the remote causing it to go to RTL, hence the ThrOUT values later. I first suspected that a faulty Tx/Rx caused failsafe RTL but as per the logs RTL only starts after line 13600 and i had been flying with no problems for 8 mins before this. Also you can see that ThrIN and ThrOUT track very nicely up to this point.

Perhaps if the day was cooler or the quad was not so heavy it probably would not have resulted in a crash but this phenomenon is worrying as i cannot find any reason for it. Unfortunately it seems that almost every time i fly now a days i crash which is getting a bit old. Anyway, i have attached the logs and any assistance would be greatly appreciated!

Happy flying

Albertino

2013-03-22 16-26 6.log

2013-03-22 16-26 6.kmz

2013-03-22 15-36-22.tlog

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Replies

  • Sorry i actually put in a screen dump of the applicable log but it looks like it is not showing unfortunately.

    Albertino

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