Hello! I had big oscillations during a flight today, and I don’t know if it is because my quadcopter is bad tuning or I am missing something. So maybe you can help me a bit because I think that roll and desired roll does’t match very well.
My quadcopter setup is:
Motor: T-Motor u7 420kv
ESC: Hobbywing x-rotor 80A
Battery: 6S 16000mAh
FC: The Cube Pixhawk 2.1
Do you thing that it is a PID problem or another thing?
And the log: https://drive.google.com/file/d/1kY2I7pRV_onzMChr8RBbcG29dkofNKhH/view?usp=sharing
Have you tuned it at all? Parameters look to be at default. Start here:
Hi Dave! Yes that drone uses the default PIDs but I don’t know if I can perform an auto tune due to those oscillations, I don’t really know if the problem are the PIDs or a desync problem with an ESC, for example.
I would like to be sure because I don’t want to crash the drone while the auto tune is running.
In any case follow the basic tuning guidelines in the link I provided whether you run Autotune or not. There are several parameters to consider based on your craft.
I have found on bigger copters it’s better to drop the autotune aggressiveness down to .05. Then after that completes move it up to .1 and do it again
Be sure to read over all the tuning instructions, but you should be able to start with these for 15inch props:
MOT_THST_HOVER 0.25 (or less)
And after hover learning
Thank you all for your answers! I will downgrade to 3.6.11 due to the problem with autotune in 4.0 and I will start with your recommendations. And if all is ok I will try with autotune, so I will keep you updated
Well, finally the problem wasn’t the PIDs of the copter, a closed look to the logs showed that only motor 1 and 2 varied the pwm signal when the copter was unstablle. So I checked those two motors and I realized that a slightly long screw touched the inductor of motor 2, and there was a short circuit between one phase and the screw.
I think that the ESC was in some moments desynchronizedwith the motor due to that problem, and after I changed the motor, the copter flew well. I still have to perform the autotune, but the real problem seems to be solved.
So thank you guys for your advices!