Our 30K Drone crashed, and we have no idea why, but we got the logs, maybe somebody can help?

[amilcarlucas]

If they have code inside that can do that, and you bought their product, you have the right to get the source code. It would be nice if you contributed it back to us in the form of a github pull request.

I do not think they did anything that fancy, but it would be good if they did

[hendjosh]

It would be fun to add it though. link

I for some reason here a script calling… I will let those with padded rooms test it though…

[bunnynugget (Bunny Nuggie)]

@peterbarker

Since you have received the running code on your vehicle, you also have
the right under ArduPilot’s license to receive a copy of the source code
to whatever is running on your vehicle.

I will certainly try and get that from them to have a closer look.

@peterbarker

Motors 1 and 2 are opposite corners of the vehicle. When one motor fails that corner will drop, so ArduPilot commands the motor output to max. The other corner is going up, so ArduPilot commands its output to minimum. Roughly speaking.

thanks for the explanation. So, according to the tlog, 2 of the motors failed at the same time, right?
When I plotted the tlog using https://plot.ardupilot.org/ I could tell the drone Rolled clockwise and the information about the motors confirms it.

Is there anything that could help indicate or rule out any sort of collision (with a bird, for instance), prior to the abnormal behaviour of the drone?
obs: I checked some vibration parameters but I am not sure they would capture this aspect - what do you guys think?

@peterbarker

Technically it is possible to fly with a motor out on a quadcopter - it involves the vehicle spinning like a top, and ArduPilot categorically does not support this. ArduCopter master will not fly a quadcopter with a motor out.

Is there anywhere I could get this information in the documentation? I tried to find it, but maybe I didn’t use the right keywords.

[bunnynugget (Bunny Nuggie)]

@amilcarlucas

I do not think they did anything that fancy

I doubt they did it, either.
Who claimed that it could fly with 3 motors was one of the course instructors and unfortunately I don’t have it written down or documented. After hearing that I felt much more confident to fly the drone with our expensive camera.

@hendjosh

It would be fun to add it though. link

that is impressive!
now that I try and picture our (RIP) drone doing it, I see a couple of issues: just to begin with, the propellers were huge and dead sharp. And as the drone was not too small either, I guess someone could’ve gone badly hurt. The size was very similar to their v2: link.

[bunnynugget (Bunny Nuggie)]

Vibration in Z seems to increase and start to drop before the others (X and Y).

Does/Could it indicate anything in particular?

The Roll seems to happen before the peak in the servo outputs. Does it mean the behaviour of the motors happened in an attempt to correct the Roll?

• Is there any indication that the roll could have been caused by a problem affecting one side of the drone (two motors at the same time)?

• Is there any clear indication that the motors had an electrical failure or does it only look like a physical/mechanical problem?

Any thoughts?

[Tarek-H (Tarek Hemia)]

Hello , did you find the cause of your problem? IOMCU reset ?
I had this on one of my machines (helicopter) it disappeared but now it’s back on a new machine, but this time every takeoff for this specific machine , I take my time to understand the real reason for this problem, I changed the autopilot (pixhawk 4 ), the servos, ESC ,bec … it change nothing , I don’t believe that a drop of 0.1v causes this !!, so why not the FMU CPU restarts too !
i can be wrong but for my case I believe that there is a kind of hardware weakness ,lack of insulation ,ground loop , between autopilot and actuators can cause this .

[bunnynugget (Bunny Nuggie)]

Unfortunately, we didn’t find the drone and all we could get were some hypotheses and speculations from the analysis of the telemetry logs.