Running Pixhawk, Ardocopter 3.5.1 with FR Sky Taranis radio. Everything previously working fine.
When I attempted a takeoff in loiter mode today my machine dipped left & right then dipped forward & aft. I tried to nreturn it to the ground & it rolled over.
Powered down & tried again after a break & same thing occurred again.
Changes before this flight were enabling simple mode on channel 8.
Ive attached t log file (crash occurs at 48%) as well as other log file.
Roll and pitch diverge badly from demand and oscillate at ~1.5 hz, which would make me suspect your RATE_P or STB_P gain terms.
Is your copter lighter than when it was tuned, or have you given it a new battery perhaps?
I recommend backing off STB_PIT_P and STB_RLL_P to the default of 4.5, RATE_PIT_P, RATE_PIT_I, RATE_RLL_P, and RATE_RLL_I by 20% to .072 and running an autotune with the copter at its minimum flying weight - no cameras, gimbals, extra batteries or payload.
thanks for your response Jonathon, very much appreciated.
I’ll give that a try. The only change to my machine has been upgrading software & attempting to change a switch on my fr sky.
I’ve never done an auto tune as I purchased the machine second hand from a reputable dealer. I’ve been through about 8 battery cycles (3 batteries) & experienced never experienced the same issue before.