APM3.4.6 RTL mode Crashed my Copter

ArduCopter Copter 3.4
1

My copter controled by an iPhone crashed today during executing RTL mode. At the time it reaches the RTL height, it dropped down to ground. Is it possible that the remote control software made this happen? it uses only GUIDE and RTL mode, and sometimes send mavlink: MVMessageSetPositionTargetGlobalInt message to controll its speed & direction. On the ground, all testing on iPhone/simulator/Copter are fine. I can’t figure it out why yet. software/hardware? Really appreciated if anyone’s help or hints for troubleshooting this problem.

log:http://112.124.25.213/2018-3-17-16-56-52.bin
http://112.124.25.213/aaa.mp4

2

Everything points to a total power failure in flight.Everything I check in the log finishes abruptly.This is just the motors but everything else stopped at just about the same moment.So it’s a power out for some reason.

power%20out
power out.png1920×431 24.2 KB

3

Yep, you have some serious power issues. Either you started out with a 4S pack that was at 3.4 volts per cell (13.6 volts), or you started out with a 3S pack that was over charged to 4.53 volts per cell.

At one point (line 2169) voltage dropped to 9.7 volts. At line 28423 voltage dropped from 12.35 volts to 2.138 volts at line 28448. Voltage dropped again at line 28495 to 1.5 volts.

After that voltage was erratic, jumping between 1.5 and 4+ volts.

Measured current is totally useless and never goes higher than 5 amps.

Here is the Auto Analysis dump:

2018-03-11 17-53-49.log
Size (kb) 2798.86328125
No of lines 33681
Duration 0:04:48
Vehicle type ArduCopter
Firmware Version V3.5.2
Firmware Hash 62a12357
Hardware Type
Free Mem 0
Skipped Lines 0
Test: Autotune = NA -
Test: Balance/Twist = NA -
Test: Brownout = GOOD -
Test: Compass = FAIL - Large change in mag_field (116.09%)
Max mag field length (662.62) > recommended (550.00)

Test: Dupe Log Data = GOOD -
Test: Empty = GOOD -
Test: Event/Failsafe = FAIL - ERRs found: FLT_MODE FS_BATT CRASH
Test: GPS = GOOD -
Test: IMU Mismatch = NA -
Test: Parameters = GOOD -
Test: PM = NA -
Test: Pitch/Roll = NA -
Test: Thrust = NA -
Test: VCC = WARN - VCC min/max diff 12.04404v, should be <0.3v

Notice the “FLT_MODE FS_BATT” error. This means the flight controller went into Failsafe because of either a low battery voltage, or low remaining capacity. This was followed by “CRASH”.

The flight controller did exactly what is was supposed to do, but unfortunately it didn’t have enough power to complete an RTL (if in fact you have the fail safe set up properly) or a Landing.

The bottom line is, the FC did not crash the aircraft, you did…

So, what you need to do is go through the power system top to bottom and stem to stern. Test EVERY battery. Make sure they hold a charge and are not damaged or swollen (aka puffed). Make sure your charger is in good working order. If you do not have a DVM (Digital Volt Meter) get one.

Calibrate the battery monitor/power module for voltage and current.
http://ardupilot.org/copter/docs/common-power-module-configuration-in-mission-planner.html

4

Thanks a lot for your answers !
my log is 2018-3-17-16-56-52.bin。