Crash Autotune and Roll Issue

Hi All!

I have a problem with my Hexa…
All the time when i try to make autotune process the Hexacopter Crash to the left side…
I changed my old Afro ESC for a New F30A and i have the same result.
My hexa… APM 2.6 Arducopter 3.2 version.

I cant understand what is the problem…
Thanks in advance.

I send the logs file.

Regards :slight_smile:

Sounds like a loss of sync issue.

Are you running SimonK firmware on the F30A ESC?

Do you have the signal ground connected?

Im running with SimonK firmware… but in the old AfroESC i tried with BhHeli and the same…
Signal Ground Conected??


I have tried now with a BlHeli firmware in the F30A but the same problem, i crash one more time… :frowning:

6 ESC F30A
6 4220 650kv

13x4 prop… ( i tested it with 12x4.5… )

I think that is some mechanical problem… O_O


Now… I change the position of one of these engines… the same.

Later i tried taking out athe red and black wires from the esc… the same.

And later i tried changing Angle_MAX to 3000 ( 30º )… and the same issue…

Ufffff… the carbon propellers… xDD


You say you moved a motor, did you move the motor and ESC together? Did that same unit fail? Or another unit in the same location?

i change the position of one engine… the problem is that always the crash is from the left side…
Then i tried to change the main engine on the left side.
Before i change all the ESC and i think that it`s not the problem…

I have read something about the Multistar 4220 65Kv sync issue… :S


Lots of motors and ESC’s have sync issues. There’s really not much we can do about it in Arducopter.

Thanks, but the strange thing is that whenever synchronization is lost is on the left side… :S


Could be the ESC on the left side?

I think no, i wrote that i have changed all the ESC for new F30A ESC.

Thanks! :slight_smile:

I have had the same on my Y6B, always left side, I have changed everything including the Pixhawk, always the same motor.
I am not sure if this fixed it but I have bumped up the minimum throttle. I noticed that over time in hover or on the bench,the RC out can drop quite low, depending on which side is higher (even by a tiny amount) and I thought that it might be desyncing due to too low PWM values. The opposite is true for the lower side, the RC out grows and can become quite high.
It is less noticeable in flight as the frame moves but in a long tethered hover without corrections it seems that the higher side motors can drop very low and eventually the motor stops. Raising the THR_MIN seems to have stopped this.
I will keep testing. I think this might be what is causing my issues as I am sure that it is a simple problem but DEFINATELY not hardware. Sounds similar to your reported issues. It might not help you but you never know.

Thanks iUAS_AUS!!

I will try too.


I read somewhere that they replaced the Pixhawk and the problem went away.

Since you have a hex maybe you could turn your APM around and rewire it. If it leans left then it must be the APM doing it since nothing else changed. If it now leans Right then its motor or ESC.


Nice idea to try and find root cause.

I did replace AND swap everything and the problem was still there with the same motor position. Strangely, it only happens on my Y6B.
Rob, I am assuming that it is normal for the motors to slowly ramp up when idling on the bench. Is that right? I think that if the frame is not perfectly level then the motors will slowly try to compensate. As it is on the bench they keep trying with no effect. On the bench my roll value was 0.44 or there about. Over one minute I would see motors 1/2 climb and 5/6 fall. I can change the behaviour by making the roll -0.44. Then 5/6 climb and 1/2 fall.
If I leave it the higher side motors will go all the way to Min_THR.
More importantly, the offset between motors is stored so if I drop throttle straight down to zero and then raise it a little bit the motors come back up spinning in the same ratio with the lower side motors going straight up to about 1450 and the lower side staying at THR_MIN until I raise the throttle by about 450 or whatever the difference is between the fastest motor and the slowest.
This problem is better if I allow the copter to rise a couple of centimetres above the bench and then there is some movement in all axis, however, if I arm and take a minute to get set then the motors are in this mode before taking off. I am trying to get some other motor to desync by changing the roll/pitch on the bench by a small amount. I will see how it goes.
This seems to lead to the syncing issue, I am not completely sure but raising THR_MIN to 150 has helped, motors no longer stop after running them for a few minutes. I think they stopped because of the offset causing some motors to keep running but the ones with lower PWM values would go below the ESC’s threshold.

That all sounds perfectly normal. The motors on the low side will slowly increase, due to build-up of I-term. If you set Rate Pitch, Roll and Yaw Imax all to zero, then you should see that they do not increase speed slowly over time. But you wouldn’t want to fly like that.

If some of your motors actually stop during that test, then I think you need to raise your Thr_Min. They should not stop.