Another crash caused by a switch to a different flight mode....
After several good flights with my pixhawk equipped quad, i had a crash soon after take off immediately after switching to alt hold flight mode. The quad immediately rolled over and fell from the sky...
I don't understand the cause, especially because i had several good flights with the same configuration, i didn't change anything since then...
If somebody can give me a hint based on the log file i attach to this thread i will be very grateful.
I also attached the video taken from the go pro on the gimbal.
Thank you in advance...
Replies
I also built a Y6 and have similar issues. Mine seemed to begin with a firmware upgrade last winter. I have a list of possible causes. Most are power related. I am getting tired of repairing and I ruined a $500 gopro.
Voltage brownout due to under capacity batteries. I am using 4s 5000 mAh, 50c. I upgraded with my latest battery to a 60c.
Power module failure
Bad power distribution board (I discovered a bade trace.) The circuitry is not capable of high current, will overheat and burn through.
Thank you again for your help!
Anyway the fact that things went bad exactely when i switched to alt hold flight mode is the biggest hint to understand that this was triggering the crash. Just don't still get why.
Your help in the analysis is very helpful anyway. Thank you again.
The reason the flight mode passes through sport mode before alt hold is that i configured two 3 pos switches of my taranis for the mode change, and to give time to activate both switches to select a mode there's a time lag of 0,5 seconds before ch5 sends the approprate pwm level for the selected mode, the problem is that in that 0,5 seconds the pwm level of ch5 goes to midposition that is the level at wich sport mode is set. This has never caused any problem, but i could even reduce that lag to zero, but this will cause the taranis to voice confirm every flight mode is passed though with the 2 3 pos switches combination before reaching the last selected mode, that is anooying and confusing, with that lag of 0,5 secs the taranis will read only the last position selected.
The pixhawk configuration is for standard quad, so motors 1 and 4 are on the right side of the frame.
As you can see from the movie of the crash, the roll is to the left, so you're right saying that it's like the motors on the left failed, what's strange is that this happened with the switch to alt hold, and i don't see any reason for which this flight mode could cause a failure of both motors on one side. Consider also that this quad had several good flights with the same configuration. Moreover i did some ground tests to make sure that the motors/escs combination didn't cause any sync issue, as reported by others with the same setup.
For sure not at close distance, also on google maps i can't see any in the area, do u think those antennas could interfere with the pixhawk? If so why would it do that at the moment of the flight mode switch?
Son, do you have bad experience around comm tower like the one pictured?
I am asking because I fly an Iris close to one of the towers, and sometimes I have funny glitches, but mostly poor 915 telemetry.
Thank you.
Paul
FW is the latest, 3.1.5, I can exclude prop issue, about motor and esc i must check, but it's not likely, the drone rolled over exactely when i switched to alt hold, till that moment it was flying nicely as always.
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