Sudden change in flight direction

[Mitteau]

Hello everybody!
I had twice the same thing: CF2 is in stable flight and suddenly change to start very quickly in some direction (and crashes). Perhaps linked with my post dated 02/20 2016 6:24pm.
Regards
Jean-Claude

[Mitteau]

I precise:
Motors are OK, no hair no problem,
CF2-Firmware 2016-02,
Slight modification on led12ring.c (described earlier).

[Mitteau]

Hello !
I send you a plot of battery values, showing 4 instabilities. I do not understand the 4 blue peaks.
I take out LED-ring. Flight looks more stable ?
Best regards
Jean-Claude

[DaGuRu]

Did you ever figure out what was going on with your Crazyflie? Mine started behaving in a similar way out of no where. I will start the crazyflie, connect to it, but if I hold even a little thrust for a while (not even enough to get off the ground) after about 5 or ten seconds the Crazyflie just goes nuts and takes off spinning out of control (even though the thrust being sent to it is still very low).

When I do this and hold the crazyflie in place i can see that the motors are just going crazy, one or two props will stop completely and the other two will go full thrust, this seems to just happen sporadically (like one prop will stop the others go nuts then the stopped prop will go crazy and another one will stop) when i watch the client its not showing me that the sensor values are going crazy or anything so I am not sure why this is happening.

[Mitteau]

Hello DaGuRu
My analysis:
1/some mechanical problem with one motor can occur during flight. I don't think is likely the case. I suppose motors are correct, with clean axis and no loss of power after crashes. This can be verified with a short run on the ground (aircraft "point fixe" in french). I use advanced flight mode with minimum thrust at 12%. Then test is clearer.
2/discontinuity in the battery electric power. This seems to be confirmed by my plot in my last post. So there can be a sudden change in attitude, then rapid cruise in some random direction and crash if the wall is not to far (indoor case). I have no experience outdoor. The question is that this failure occurs even when the battery is fully charged.
Thank you for your opinion.
Best
Jean-Claude

[DaGuRu]

Hey thanks for the response, hopefully it is just an inconsistent charge in the battery, the motors all seem to be running fine at the start then after about a minute or less one random motor will stop and the others will start spinning at max thrust. From what I can tell it seems as if one of the sensors or the stabilizer is having issues after running for a bit, it almost seems like the stabilizer is only worry about the average thrust of all 4 motors (turing one off and ramping another to compensate)

* edit - My issues aren't with the battery, tried running it fully charged and reflashed the firmware but i am still having the same issue

[Mitteau]

Hello DaGuRu
I changed two of the weakest motors. I had to adjust trim. Same behavior.
Regards
Jean-Claude