[f5soh]

What arming settings do you use ?

[TheOtherCliff]

f5soh: What do you think about the inverted falling incidents that you know of, where CruiseControl was active?

User Stopping motors allow it to fall, speed up, and tumble.  3 seconds of fall would get it fast enough to require high motor speed to recover from stalled props.  Reversed stabilization (spinning prop is more drag than slower prop) keeps it falling inverted and motors never get very fast (as discussed earlier in thread)?  It would be a self levelling mode for the control reversal to keep it inverted.

Assuming you can recover in Rate mode no CC, I think that Attitude with CC would be the only one that would not let you recover.  Rattitude is Rate at full stick.

Of course stalled props would cause problems in any mode but at least you would have control over the thrust (default settings hold thrust at 5% when using CC and inverted).

I just thought of a way to test this (without a wind tunnel).    Use Rotate Virtual to rotate level hover into a 90 degree roll bank.  Mount quad very strongly on a long broom handle.  Set pitch and yaw PIDs to zero.  Motors off.  Hold it out the car window so that FC considers it inverted and airflow is same as falling inverted.  Accelerate car to desired speed.  Start quad motors.

[batata003]

@TheOtherCliff sorry for long time without answering. Just yersterday I had time to make the test you said. I realized it looks like an intermitent problem or some very particular thing in the code of librepilot that makes this problem happens.

I did this: throttle to about 50% for 10 seconds (holding of course the quad in my hand) and after that I set throttle to minimum (no throttle at all). After 3 seconds I turned the quad upside down and waited 5 seconds, after that I tried applying high throttle and sometimes the motors spin very fast and other times the motors spin not fast (I belive it's the 5% thing you said).

I also realized that while inverted if I keep shaking my drone, when I throttle up the motors spin very fast as they should. But if I keep it upside down without shaking the motors would not turn very fast as they should to try to recover from the fall.

I am really out of ideas of what could be causing this. Disabling cruise control fix the problems everytime, I set throttle to MANUAL and this issue does not happen anymore so I am 100% confident this problem is related to cruise control.

MAYBE the other suggestion of @TheOtherCliff also could have happened: stall props or a very strong rotation in the opposite direction of the prop (cause by the wind hitting the props) didnt allow the motor to spin to the right direction and start working.

[TheOtherCliff]

You should realize that if you are using CruiseControl and it is inverted, that some motors will be very fast and others will be 5%.  It is designed that way.

It is just trying very hard to make it upright.  There is no way to get all 4 motors to run fast.

If you tilt it a little the other way, the fast ones will be slow and the slow ones will be fast.  180.0001 degrees upside down and these motors will run to try to pull it to 360.  179.9999 degrees upside down and other motors will run to try to pull it to 0.