Help with tuning Hexacopter

ArduCopter Copter 4.0
1

Hello everyone,

I have been struggling with my hexacopter setup, where I am unable to autotune, due to an error that the drone is not able to stabilize.

Indeed the drone oscillates, which I have tried to control following the ‘initial aircraft tune’ ( Initial Tuning Flight — Copter documentation). I tried reducing the following parameters as indicated in the post, but it only led to slower oscillations and did not eliminate them: ATC_RAT_PIT_P, ATC_RAT_PIT_I, ATC_RAT_PIT_D, ATC_RAT_RLL_P, ATC_RAT_RLL_I

A forum post with similar issues (AutoTune worked on older firmware but stopped working properly on Arducopter 4.2.2 - #11 by AmroA) provided parameters to test, which have not resolved the issue either. Moreover, I tried to use the FFT analysis indicated in that post, which showed 25Hz, (which is far off the expected 1000Hz). Not sure if this is directly related or I am doing something wrong?!

I would appreciate any suggestions or insights that could help me resolve this issue. Attached I show a video that shows the oscillations (if you look carefully). The logs are also attached. The 20 second video corresponds to minute 3:30-3:50 in the logs. video stuff - Google Drive

Setup:
Navio2
ArduPilot 4.0.0 (also tried 4.2)
Skystars Talon 40A 3-6S
Racerstar Racing Edition BR2312

Thank you in advance for your help!

2

Ah, that’s too bad. Can you not run the latest Stable version of Copter?

Yes, outputs are oscillating. I would suggest setting the Rate Pitch/Roll P&I equal at 0.100 and set these:
PSC_ACCZ_I,0.32
PSC_ACCZ_P,0.16
Set these to collect data for the Notch Filter that you haven’t configured:
INS_LOG_BAT_MASK,1
INS_LOG_BAT_OPT,0 (normally 4 would be used here but you are on old firmware)

Make a short hover flight in AltHold and then review the motor ouputs for oscillation and configure the notch filter.