Drone out of control, no crash

[IalexI]

Hi there,

I am a happy Mavic Pro user for some while.

Yesterday, I was flying at the beach and received the following error messages:
"Gimbal vibrations"
"Gimbal overload"

Suddenly, the gimbal went totally crazy and the craft started to spin while it was over the ocean. In an attempt to save the craft, I firstly increased the flight altitude. For somehow, I was able to accelerate in the right moments to fly it back and I was even able to land it safely. I believe it was not the toilet bowl effect, since the craft was able to hover on the same place and rotated around a spin axel in the middle of the craft.

Everything is stock: The drone is unmodified (hardware + software) and I am using the newest firmware and DJI GO4 app on an Android mobile.

I have attached the flight log to this post, as well as a visualization of the flight log and a Youtube video showing the exact moment when the Gimbal went haywire.

Could you point me in a direction, what is wrong with the drone? I basically don't understand the connection between the gimbal issue and craft spinning.

I have this drone for about a year, never crashed it and it's quite sad to see how it's falling apart in the middle of a flight.

Please help!

Best regards!
Alexander

Flight log visualization: DJI Flight Log Viewer - PhantomHelp.com
Youtube Video:

 

[BigAl07]

Welcome to the forum

Was were the winds at the time?

 

[eaglesurfing]

Welcome to the forum and enjoy.

Please use one of the best forum search options.

Wow that was really close. It looked like a real battle to get almost to dry land.

 

[Mavikhan]

WELCOME ABOARD! ?

 

[IalexI]

@BigAl07: there was almost no wind at the time.

Could you let me know if the systems of the gimbal (accelerometers?) are connected with flight stabilization? I still don't understand why both problems appeared at the same time.

 

[teeroy]

Looks like quite the rodeo.

 

[Yogi053]

WOW!
So glad you got it back. Cannot wait to see if any experts on here find the cause.

 

[Thomas B]

Welcome to the forum from the deserts of Arizona! Enjoy.

interesting question you pose. Glad you didn’t lose the drone.

 

[fguthrie]

I wonder if a bird collided with your drone. It seems odd to me that one minute it is working perfectly and then the next the gimbal goes bonkers and the drone starts spinning. Have you tried replacing the propellers to see if that fixes the spinning issue? Also, any indication of feathers anywhere?

 

[spamgnome]

Similar thing happened with my MA1 the last time I flew it. At the time, it was flying a Litchi mission in autonomous mode, so I quickly took back manual control, and was able to wrestle it back to me. I haven't really sat down to analyze what might have happened, BUT I suspect it may actually have to do more with the controller rather than the drone. Suggest you calibrate everything. Controller. Compass, IMU. Then see what happens. For the next few flights, stay over land

 

[DanMan32]

Similar thing happened with my MA1 the last time I flew it. At the time, it was flying a Litchi mission in autonomous mode, so I quickly took back manual control, and was able to wrestle it back to me. I haven't really sat down to analyze what might have happened, BUT I suspect it may actually have to do more with the controller rather than the drone. Suggest you calibrate everything. Controller. Compass, IMU. Then see what happens. For the next few flights, stay over land

That would explain AC not maneuvering exactly as commanded,, but doesn't explain gimbal..

Gimbal does communicate with IMU. When my P3 started acting up, first symptom was camera view looking like it was set to FPV. Then got a compass error, then it went to ATTI where flight and view was level again.
As I was about to orient and fly back, it went back to normal GPS navigation.

 

[earth3rd]

Looks like quite the rodeo. View attachment 122194

How on earth did you get it to come back?

 

[SpitFire]

Welcome to the forum from Chicago the Windy City.
Looking with great interest what will be the review, of what happened to your bird. I have 2 MP's, one old and one new.

 

[Ol' Sparky]

Had similar issues first M2 Zoom flight this year. First battery was fine, but second flight, Gimbal starting shaking, pointed down & wouldn't respond, got several overload messages, briefly lost signal and video a couple times, a strong R/C interference warning, a high wind warning even though there was no wind at all. It had been a while since last flight so I updated firmware and software the night before. There were IMU issues, so tried a calibration but it wouldn't go out in the field, but all the indicators showed green, so I flew and had the issues. Took it home and did a proper IMU calibration and downgraded the firmware to the previous version. Hoping that solves the problem...but haven't been out yet. If there are no issues next time, I'll put the new firmware back on and see if it flies straight.

 

[slup]

Hi there,

I am a happy Mavic Pro user for some while.

Yesterday, I was flying at the beach and received the following error messages:
"Gimbal vibrations"
"Gimbal overload"

Suddenly, the gimbal went totally crazy and the craft started to spin while it was over the ocean. In an attempt to save the craft, I firstly increased the flight altitude. For somehow, I was able to accelerate in the right moments to fly it back and I was even able to land it safely. I believe it was not the toilet bowl effect, since the craft was able to hover on the same place and rotated around a spin axel in the middle of the craft.

Everything is stock: The drone is unmodified (hardware + software) and I am using the newest firmware and DJI GO4 app on an Android mobile.

I have attached the flight log to this post, as well as a visualization of the flight log and a Youtube video showing the exact moment when the Gimbal went haywire.

Could you point me in a direction, what is wrong with the drone? I basically don't understand the connection between the gimbal issue and craft spinning.

I have this drone for about a year, never crashed it and it's quite sad to see how it's falling apart in the middle of a flight.

Please help!

Best regards!
Alexander

Flight log visualization: DJI Flight Log Viewer - PhantomHelp.com
Youtube Video:

The shaking gimbal is most probably a secondary effect & not a root cause ... it's easily seen in your clip where something starts to vibrate first, then a jello effect is introduced in the footage which also is a side effect of vibrations.

My guess in this stage is that something is going haywire in the rear that develops to a situation where that prop/motor no longer can create enough torque to counterbalance the three other ... & that makes the AC start to rotate.

Would be interesting to take a look at the motor data ... for that the mobile device .DAT log is needed. Go here & read up on how to retrieve --> Mavic Flight Log Retrieval and Analysis Guide (read under section 3.) The correct .DAT log ends with FLY167.DAT attach it then in a new post here.

 

[IalexI]

Dear all,

thanks for all the reply and your input. Also thank you very much for the warm welcome to this forum!

Before I will try the next flight, I would like to fully analyze the situation. The gimbal is defective for sure. I have ordered a ribbon cable from Amazon and if time allows, I will try to fix the gimbal by myself.

@slup: I have attached the requested file to this post and I am very curious what you can see in it. Which software do you use for analysis?

@fguthrie There were no signs of a bird contact, no scratches, no feathers.

@spamgnome I also thought about the possibility of a miscalibrated controller. My understanding is that you can see the stick inputs in the log file visualization (DJI Flight Log Viewer - PhantomHelp.com) and they seem to be fine.

Best regards and thanks for your help!
Alexander

 

[MavicProGlow]

Similar instance happened and I am friends with a repair shop that suggested that I recalibrate the vision sensor to start in dji assistant then calibrate imu, and finally the compass in that particular order after time imu and compass calibration variations along with vision sensor inactivity due to low ambient light situation causes the imu and vision sensors to almost work against each other reading data compass is providing.

 

[IalexI]

I took a closer look at the documentation regarding log file download and analysis posted by @slup.

I have converted the DAT file into csv and loaded this into CSVViewer (graph attached).

This looks interesting. You can see the very moment when the problem arises after approx. 45 seconds. It seems that the RPM of all 4 motos dropped at the same time for a very short period. After this, the curves also don't look normal, but I am not sure how to interpret them.

 

[VZ2]

Looks like the motors are executing commands from IMU raving RPM up and down and gimbal was trying to compensate for the shake of the quad. Why IMU gives erratic input to motors and the bird still able to fly (more or less)? Some sensor got loose, intermittent connection... IMU glitch or persistent errors...
Have you tried to run it again? Like spin motors on a ground and look at gimbal and overall behavior?

PS: by doing that I would tied up the quad just in case to prevent it to fly away if IMU will continue to act...

 

[IalexI]

@VZ2: I powered it on yesterday just to find out that the gimbal is defective for sure. It moves to an erratic position right after power-on. Calibration fails. I didn't want to run motors, yet.