I had a problem with my cinelifter, it had a roll problem and then I changed the FC and it was a gyro problem but after I tuned my quad with the new FC I had a bigger problem. i had a 16 second flight when i did a roll the drone went crazy and went straight to the ground, broke a motor base but that's all the damage besides the broken propellers. I have no idea where the problem is, does anyone know what it could be? I will include the image of the blackbox of the accident. My build is a thicc 3.0 with a speedybee f7 v3, 2 xrotor 65A hobbywing esc, with 3115 brotherhobby 1050kv motors, old airunit, crossfire diversity, gps m10dq geprc

Blackbox here
https://drive.google.com/file/d/120VOnlR...sp=sharing

Why didn't you include the log file instead of just a screenshot?

(20-Nov-2023, 06:13 AM)voodoo614 Wrote: Why didn't you include the log file instead of just a screenshot?

i put in the post 

so, it looks like you did not have airmode active. when you went to zero throttle to do the roll, the quad lost control.

(20-Nov-2023, 05:27 PM)voodoo614 Wrote: so, it looks like you did not have airmode active. when you went to zero throttle to do the roll, the quad lost control.

i have airmode active, i have 2 or 3 flights doing a lot of rolls and flips, and this happend, and i dont know why

I guess it does not flag Airmode when you have it enable all the time.

The other thing I notice is motor 8 goes to 100% as you were going into your left barrel roll. If anything, the left motors should be lowered than the right side motors. But #8 was at max.

To be honest, I am not sure what to make of this. I can't think of a reason why #8 would go to max. it was only a tenth of a sec into your roll.

i cant read logfiles; heavy liftersettup, one motor to 100%
sounds in the direction of a motordesync?

increased motortiming, lowered startup/rampupower and demag compesation, in that order, can maybe solve a desync issue.

but flips and rolls on a x8 lifter quad? maybe you are asking for more than makes sense for that settup possibly?

3115 is a lot of mass from the motor, it might not become responsive

(20-Nov-2023, 08:25 PM)hugnosed_bat Wrote: i cant read logfiles; heavy liftersettup, one motor to 100%
sounds in the direction of a motordesync?

increased motortiming, lowered startup/rampupower and demag compesation, in that order, can maybe solve a desync issue.

but flips and rolls on a x8 lifter quad? maybe you are asking for more than makes sense for that settup possibly?

3115 is a lot of mass from the motor, it might not become responsive

its not a desync, they dont go to 100% and stay, they alternate from one side to another, like left right left right. and i think the drone has to make a move and stay in the air, if the drone make the roll or the flip slower than a 5 inch its ok, but it cannot drop from the sky with no reason. i think

(20-Nov-2023, 08:11 PM)voodoo614 Wrote: I guess it does not flag Airmode when you have it enable all the time.

The other thing I notice is motor 8 goes to 100% as you were going into your left barrel roll. If anything, the left motors should be lowered than the right side motors. But #8 was at max.

To be honest, I am not sure what to make of this. I can't think of a reason why #8 would go to max. it was only a tenth of a sec into your roll.

i dont have any idea of what is this, and i tested in 2 diferent fcs and with the second one i could tune the quad and then this happend.

So normally, a motor signal goes to 100% because the FC is trying to get the motor to spin, but it is not responding. So the FC keeps on sending signal for the motor to spin until it maxes out. The motor is actually not spinning at 100%, just the signal. One reason, as hugnosed has mentioned, is the motor desyncing. Hugnosed does have a point.

(20-Nov-2023, 09:45 PM)voodoo614 Wrote: So normally, a motor signal goes to 100% because the FC is trying to get the motor to spin, but it is not responding. So the FC keeps on sending signal for the motor to spin until it maxes out. The motor is actually not spinning at 100%, just the signal. One reason, as hugnosed has mentioned, is the motor desyncing. Hugnosed does have a point.

I will disassemble the drone and use the esc with a 5 inch motors to test that without the risk of a 9 inch octo flying

(20-Nov-2023, 09:45 PM)voodoo614 Wrote: So normally, a motor signal goes to 100% because the FC is trying to get the motor to spin, but it is not responding. So the FC keeps on sending signal for the motor to spin until it maxes out. The motor is actually not spinning at 100%, just the signal. One reason, as hugnosed has mentioned, is the motor desyncing. Hugnosed does have a point.

Another question is, this can be the i term windup? A friend mentioned this but i never heard this before.

Not sure this looks like a desync issue



As soon as your motors start throttling up past 60%, you can see the gyro starting to oscillate like mad suggesting that there is a vibration issue of FC not being well mounted, or something loose on your frame, imbalanced motors/props, etc. Do you have dvr of this flight? From the log doesn't look like it got to the roll.

(20-Nov-2023, 10:25 PM)matheus.fpv Wrote: Another question is, this can be the i term windup? A friend mentioned this but i never heard this before.

The following is source from BF 4.2 Tuning notes

Quote:If the pilot requests a change in turn rate that is too quick for the quad to deliver, the gyro signal will lag setpoint, and will be a large error signal. I will start to accumulate to help correct this. iTerm_relax will try to control this accumulation. If iterm relax is inadequate for the amount of error, a large amount of I may accumulate, and when the pilot stops the flip, all that accumulated I will drives a movement in the reverse direction, which slowly fades away, until it gets back to zero. That's the single, fairly slow, 'bounce-back' event that the pilot sees when they terminate the flip.

This phenomenon is called 'iterm windup'.

We use the iterm_relax and iterm_windup settings to control iTerm related bounce back. The defaults for these parameters work very well in 4.2 for 'normal authority' builds. iterm_relax, at default of 15, strongly suppresses I accumulation during normal flip and roll inputs. iterm_windup works for yaw problems, and since it usually isn't needed at all, it is off by default.

'Low-authority' quads, however, will tend to get bounce-back after quick flips or rolls, and after quick yaw inputs, because they have much more delay and error than normal in relation to the stick input. Betaflight's iterm_relax and iterm_windup values will need to be adjusted for these machines.

As you can see, the I-term windup has to go with bounce back after a flip or roll or quick yaw. I don't think your even roll very much before going out of control.

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(20-Nov-2023, 10:05 PM)matheus.fpv Wrote: I will disassemble the drone and use the esc with a 5 inch motors to test that without the risk of a 9 inch octo flying

You might not see the same behavior with a different setup.

(21-Nov-2023, 12:17 AM)mstc Wrote: Not sure this looks like a desync issue



As soon as your motors start throttling up past 60%, you can see the gyro starting to oscillate like mad suggesting that there is a vibration issue of FC not being well mounted, or something loose on your frame, imbalanced motors/props, etc. Do you have dvr of this flight? From the log doesn't look like it got to the roll.

yes, here is the Dvr of this flight. and i will not disasemble the drone, i will wait the repair parts and test again with more caution.
https://drive.google.com/file/d/1qEJPP98...sp=sharing