High vibration cause lost rc control

I have some vibration issue in my 26cc fixed wing when I test in ground, that is look some switch between DCM and EKF3, but very strange is that lost rc control , then flight mode enter into RTL but can not switch to manual mode.
I believe that is not hardware issue
the log

does anyone have specific cases where software caused vibration issues?

Hi @jinchengde

Your 26cc engine is shaking the plane to death. The log shows a lot of sensor clipping by vibrations.
There is no chance to fix this by software.

Possible hardware fixes:

  • run in the engine properly. It just needs some time.
  • find the “sweet” spot on te carburetor settings
  • balance the prop

Good luck.

I wish to know what cause RC control lost? vibration cause attitude error is make sense, but why lost rc control and can’t back, that means you have no chance to switch back to MANUAL mode if that happen.
I fallback the firmware to 4.0.9, rc control lost no happen again. of course, maybe no enough test, but in 4.1.3, very easy to repeat.

your log says it has entered throttle failsafe. so your throttle is going below failsafe value meaning your receiver is loosing connection. I would guess you have a problem with how you are powering your flight controller, receiver and servos along with the massive vibrations.

yes something strange is happening with the servo 5v rail

the failsafe value for throttle is about 950, no below for that.
the failsafe action for reciver is hold the pwm value, the failsafe trigger for flightcontroller is based on the rssi
so that is very strange
the servo 5v(actually 6V) rail became a line because no move for the servo because the rc control is lost

no even with the servos still there should be some noise in the signal.

There is no such thing as RSSI failsafe, it will only activate if the RC signal has been totally lost for over a second or throttle value goes below failsafe value.

your servo voltage is very noisy, how are you powering it? It shouldnt have spikes like that when the servos are barely moving.

I used hobbywing ubec ( UBEC 8A (Large Current BEC) - HOBBYWING North America (hobbywingdirect.com)) for servo power.
do you suspect that cuased by ubec?

I am not sure, even if your servo power failed that shouldn’t cause your receiver to loose connection. how is your pixhawk and receiver powered? are you using a power module? what receiver is it?

I find that cause by the internal error 0x3000, that means io reset, maybe I need the replace the flight controller to new.

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FMUV5 servo voltage monitoring is also on the iomcu. It seems that the communication lost of iomcu, or iomcu restarts or freeze.

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its possible the vibrations have shaken something and exposing a bad solder joint in the controller. your probably safer to replace it. but is your ignition system near your flight controller?, the spark could cause issues if its too close.

yes, I replace fc to new one and test on the ground, no happen again.

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You still need to fix your vibration issues.