Hi guys,
can anyone help dig out from my flight logs why I had a fly away with my hex?
Logs are here:
Log - https://www.dropbox.com/s/fi80fz7hkkfveep/Log.log[1]
Kmz -https://www.dropbox.com/s/osolp2i8ym5pl31/Log.kmz
The hex seemed to stop responding to controls even through I initiated a RTH after probably 60 seconds.
When I found it (thank goodness for TX telemetry) and picked up the many pieces I did check the RX and Pixhawk and the RTH correctly responded in mission planner.
Im thinking of what to rebuild, but without knowing what happened I'm a bit concerned.
Any help is appreciated
thx
Replies
By looking at your logs there seems to be something off on your pitch. Did you do the accelerometer calibration and ESC calibration. You may need to calibrate your voltage sensor as well. Tell us a little more about your hexacopter. Type, speed controllers, battery, BEC, receiver, motor and prop size and so on as this may help with a diagnosis.
According to the logs the pixhawk did receive the RTH. Only when it was far away did the receiver loose a signal. Also go into a little more detail about your flight. Did it ever seem to fly correctly for you?
Both the accelermeters report the same information back so I don't think it is a hardware issue on the Pixhawk. My gut feeling is to check if the motors are connected in the correct order.
I also noticed that motors 3 and 5 would max out. This could be either a bearing going out in one motor or the hexacopter was not balanced.
Below is a summary that mission planner produces.
Log File C:/Users/rob/Desktop/Log.log
Size (kb) 3011.08984375
No of lines 41218
Duration 0:03:57
Vehicletype ArduCopter
Firmware Version ArduCopter
Firmware Hash
Hardware Type
Free Mem 0
Skipped Lines 0
Test: Brownout = PASS -
Test: Compass = WARN - Moderate change in mag_field (32.55%)
Test: Dupe Log Data = PASS -
Test: Empty = PASS -
Test: Event/Failsafe = FAIL - ERRs found: FS_BATT FS_THR
Test: GPS = PASS -
Test: Parameters = PASS -
Test: PM = PASS -
Test: Pitch/Roll = FAIL - Pitch (-62.17, line 28052) > maximum lean angle (45.00)
Test: Underpowered = PASS -
Test: VCC = PASS -
Hi Rob,
thank you so much for the info, this reassures me a lot!
My setup was (as it was destroyed in the crash!!):
It had flown probably a dozen times perfectly with no real issues apart from it constantly low-balling the remaining battery, after each flight id only put back in 2000mah into the lipo, despite alarms during each flight. I'd programmed mission planner for a 5000mah battery.
The only difference on the day of the crash was I went too high and I was flying in a sort of valley, it looked like the winds were way faster higher up than at ground level.
Are 3+5 the back two props, if so could it have been that the wind caught under it and it never managed to dip its nose enough to fight the wind?
Any more help is massively appreciated!
thx
Sorry about the crash, where you able to salvage anything?. Motors 3 and 5 are the front props. Here are how the props are setup.
3 5
2 1
6 3
I looked at your pitch logs and I think your hexacopter was trying to come home. When you first switch to RTL your pitch goes to negative 60. If it Maybe someone else will see something. Do you recall which way the wind was blowing? Looks like the hexacopter was pointing south-south east and trying to come home but was blown north until the battery ran out and crashed.
Below are the graphs of the pixhawk's outputs to the ESCs. It also shows the mode and errors. The purple line is your relative altitude.The second graph is zoomed in just before the crash.
Rob
Hi Rob,
I think in that case it must have been the wind, SSE was home so it was pulling in the right direction but there was a strong northerly wind.. live and learn, next time drop far lower before RTH I guess.
I saved the FC, RX and 5 of the motors, one of them was buried underground from the impact...!
I'm now looking at what to build next, either a smaller quad as it'll be less prone to getting swept away in the wind, and likely keep me closer to the ground... or a plane.. decisions decisions!
Any thoughts on direction?
I started with a tricopter and a APM 2.5.2. Got my feet wet with that. I have had a few crashes but I learned a lot from those crashes. I applied what I learned on my tricopter and now have a hexacopter with the Pixhawk.
I would look at making your own quad out of wood. Some 10 or 12 cm square wood and a thin plywood base and you will have an excellent repairable quad. You will even have an extra motor and 2 ESCs. Your setup should be able to carry a gopro or a digital camera.
How bad is your motor that went into the ground. If it is only a bent shaft and probably a bearing you can replace those. I would then build a wood hexacopter. They are really stable as long as the wind doesn't take them away.
Hi Rob,
sorry to trouble you but I'm hoping you may be able to help me again!
I've setup my new quad however the loiter/position hold mode is not as good as it used to be, whenever I engage it I get quite an amount of drift. The compass has been calibrated and within mission planner the horizon view shows that the copter knows what is flat.
Here are my logs from two flghts - https://www.dropbox.com/s/oqgxugxb9aaz5bg/bin%20files.zip
Do you have any pointers?
Many thanks
Will
I ended up getting a hobbyking dead cat quad, cant complain for £30ish all in :)
The buried motor still turns so it could be ok, I'll spin it up and see how off center (or not it is)
back to flying!