Servers by jDrones

Log Help: Work Solo fell out of the sky


(Saijin_Naib) #1

I’ve posted this on 3DRPilots as well as the FB group, but I wanted to get some more eyes on here if at all possible so I know what to expect for the upcoming season, and to possibly address any problems I may have with my maintenance schedule.

To me, it was seemingly running just fine. Motors sounded smooth, they cogged cleanly when moved manually. I check the auto-analysis in Mission Planner after most jobs, and didn’t get any warnings I wasn’t expecting (slow loop, etc). The props are fresh Master Airscrew props which have seen 0 abuse (I store/transport them in the microfiber drawstring bag). The battery pack lights even report roughly the same percentage as the last I saw on my remote, so it doesn’t seem the battery crapped out. From watching the log playback, I almost want to say I had an ESC brownout and it couldn’t recover, or possibly I had a bird-strike. I don’t think any prop threw a blade since I recovered all the pieces of the props at the crash site, and I would expect that if a blade got thrown, I wouldn’t find it laying at the site of impact.
Thoughts?
Thanks!

Attached in the below OneDrive link are 4 logs:
01_DATAFLASH_2ND_LAST_KNOWN_GOOD.7z
This log is the oldest field flown the day before the crash.
02_DATAFLASH_1ST_LAST_KNOWN_GOOD.7z
This log is the last field flown the day before the crash.
03_DATAFLASH_CRASHED.7z
This log is the dataflash from the crash.
04_TELEMETRY_CRASHED.7z
This log is the tlog from the crash.

https://1drv.ms/f/s!AvMZEGXuAwQzqNMn5KL8pm7ADImyEw

Thanks for any and all help!


(Rick) #2

The logs indicate a failure on motor/ESC 4. The drone rolls right and pitches up, even as motor 4 throttle is increased to compensate.

It’s impossible to know exactly why motor 4 failed from the logs, but I noticed that the drone was flying at maximum performance for certain sections of the flight. It looks like it must have been a very windy day, as the drone was unable to reach its speed target when flying northwards while at full throttle, and had some difficulty maintaining attitude. Meanwhile, it flew nicely at ~35% throttle on the southward transects. It crashed on a northward transect, so I suspect an ESC or motor might have overheated from flying at full power for an extended time.

I’m not really familiar with Solo hardware, though, so someone else might be able to comment on whether the overheating is a likely cause.


(Saijin_Naib) #3

That analysis proved very valuable. It corroborates what a number of other analyses found in the 3DRPilots thread, and even helped narrow it down to one arm of the quadcopter.

I’m not sure if you had the opportunity to look at the older logs as well to see if perhaps there were any signs that this was a combination of mechanical+electrical failure? Possibly a motor wearing out? The auto-analysis showed decent motor balance flight to flight, so I never replaced the motors/bearings.

In terms of the Solo hardware, it was seemingly likely the ESC fault where ground bounce/lift happens due to the Black Cube signaling at 3.3V and effectively browning out under load, which is what the Slew Rate Code from 3DR attempted to “fix”. It apparently was always possible to trigger this failure by harsh flying conditions, which I likely encountered as it was windy, hot, and higher elevation than normal for me.

Thank you for your time in helping me gain further insight into this.