a few weeks ago my TREX600 (with Pix-Mini) , while hovering slowly in loiter mode, suddenly tilted backwards and crashed into the ground with the tail boom. In a fraction of a second. Before that it flew several flights without any problems.
I was so frustrated that I put the heli in the corner and no longer touched.
Now I looked at the log file after all. I would like to find out of course what it was due to.
I suspect it was the GPS.
In the log you can see that the number of satelites drops to zero just before the crash. Also there is a message “GPS glitch” and “Glitch cleared”.
Now I wonder, is the holybro GPS module itself the cause of the error or is the error somewhere else?
Another possible cause would be a faulty connection or a too low voltage in the on-board voltage.
I have looked at the last logs of flights before the crash.
Two flights before I also had the situation that the number of satelites went down to zero. However, no additional GPS messages came
On these flights, the on-board voltage had also dropped to min 4.52V in between. On the previous flights, the voltage was always above 5.0V.
Therefore I suspect that the GPS satellite drop comes from the low voltage.
Before I change both, the GPS module and the power module, I would be glad if I could get your opinion about my problem. Maybe the cause of the sudden crash is somewhere else entirely.
@heri with the way your log abruptly ends with out showing the actual crash, I think your controller reset in-flight. Was there another log on your flight controller after this log. probably dated the same day as your crash. This would show the controller booting up after the in-flight reset. If you have it, please post the log.
no, unfortunately I did not make another flight after that. The heli was very destroyed.
I removed all electrical components from the destroyed heli and left everything in the corner for weeks. As already reported.
A few days ago I removed the memory card from the FC and then looked at it on my computer.
Stupidly, yesterday I reassembled all the electronic components on my workbench as a test and connected them to the power supply. Just to see what still works. However, in doing so, I did not insert the memory card into the FC. Stupidly, this caused it not to write a log file on the first boot after the crash.
However, what I noticed during my test was that if I moved the FC back and forth very wildly, it rebooted!!!
I will insert the memory card again today and try around with it. I can link the resulting log files here.
I may have found the error.
With my TREX I had not connected the power supply for the FC directly to my drive battery. I fly with 12S and the power board can only handle 10S. Therefore I had made the power supply of the FC with an additional battery, which also supplies the servos with power.
Probably this power supply somehow did not work properly. Maybe the servos used too much amps, so that there was not enough current left for the power board.
I’ll have to experiment with my test setup on my workbench to recreate the situation.
On one test already done, the volt strength collapsed to 4.62Volts. When this happened, the FC did a reset.
This test setup does not correspond exactly to the conditions of the crash flight. Nevertheless, a drop in voltage may have caused the reset. Probably the GPS glitch was also caused by the voltage drop. And this was a harbinger for the following reset of the FC.
Bill, there was no second log from these day on the storage. But, I think the log will only be written on the storage, when you arm the heli? Isnt it? Or am I wrong?
So, because I did not arm the heli again, the FC did not wrote a new log after the reset.
If it was a watchdog reset then it will reboot and start a new log as soon as it reboots. I am sorry to hear that it could be a power issue but with the way the log abruptly ends, that is the likely cause.
yes, I am increasingly thinking it was a voltage problem.
I will test this further on my workbench and reconsider my voltage supply.
I had a different power supply arrangement in my other heli, the mechanics from the Vario Bell 230 fuselage. There I had no such problems during my adjustment flights. Unfortunately, I have not come to a satisfactory conclusion with this mechanic
result with the adjustments (See my old thread on this subject).
It unfortunately crashed the TREX that was flying well. The frustration from both crashing the Trex and not being able to handle the vario mechanics has brought me away from the FC.
I will try it again with a new test helicopter (Mikado Logo 600 SE) on the subject of FCs.