My 15 kg Quad with 30 inch props fly ok in Altitude hold and loiter mode but will not start autotunning unless give a small nudge with RC and it will twitch only once and stop.
I change filter parameter to 10Hz, Agressiveness to 0.075, deadzone on RC1-4 to 60 and tunning Roll axis only
link to .log file
See/join this thread: Autotune; why does larger copters not twitch, unless I move a stick?