CRASH_ potential Thrust Loss

Yuric1991 · October 1, 2021, 3:55pm

Hello all,
I am building a quadcopter and It has been flying fine. Today I was doing a long range flight test and everything was fine until when I started to return then all of the sudden the copter started wabling then potential thrust lost then it crashed.
I dont understand the main cause. Can someone help diagnose this with the below logs?

-My motors and ESC are U8LITE-X, the KV190+ALPHA 60A LV+MF2815 30mm 1cw R, 1CCW R, 1CW G, 1CCW G

I am running Cube orange

https://drive.google.com/drive/folders/14E76-0crD4GrstSFHOjfH15WWjBk89G7?usp=sharing

xfacta · October 1, 2021, 10:08pm

Seems to be Motor/ESC1 losing thrust and is eventually commanded to maximum. Without it working the other motors/ESCs struggle to maintain flight.
I dont see an obvious cause, like huge current spike indicating an electrical fault. My personal opinion is use different ESCs or this will happen again.

Yuric1991 · October 2, 2021, 9:39am

HI Shawn, thanks for your reply. how did you tell it was ESC1? Would appreciate guidance to see which motors esc was faulty.

Alvin · October 4, 2021, 3:27am

This can be told from the RCOUT. As you can see RCOU.C1 went maximum, this is a sign of ESC1/motor1 not getting enough thrust output as it should be. Thus Ardupilot tried to raise the output to regain lost thrust.

Yuric1991 · October 4, 2021, 8:13am

Thanks Alvin for the explanation. We are trying to understand why that happened, may be the pilot was a bit aggressive in the maneuvers?

Regards

Alvin · October 5, 2021, 2:57am

As there was no significant voltage drop or high current consumption during RCOU.C1 went maximum, it seems there was no short circuit.

It may be mechanical failure or cable/connector disconnected / etc.

Maneuvers were not too aggressive before problem appear. At least achieved attitude is following desired attitude quite well.