So I am using a pixhawk on a quad and it works great if I just let it hover, POS hold is rock solid and so is alt hold. But in AltHold or POS HOLD as soon as I give it some forward momentum and then back or just sharp turns it instantly goes 100% throttle until I switch it to Stab and I have to let it fall for a bit until its back at the level it started at at.
Now I know it's vibrations because I review my logs and the Z, x y, accel is great until it it puts out more throttle then it goes crazy and thats when alt hold misbehaves. I tried EKF and issue still happens, I tried really thin "airy" foam but compressed with the same foam on top (made a pixhawk sandwhich), my latest was moongel and I did 2 peices at each end and used its standard pre cut size. I was thinking of doing 2 layers next...
So I am trying to find out which motor, prop is the issue but I have gone through a number of props (I just have been flying normally and not using RTL or alt hold (RTL uses ALT hold so if it goes into RTL I lose my quad in the sky forever)
I switched out a motor since it sounded funny on the bench although I felt minimal vibrations when testing with out props. It just has a "hum" vibration, hard to explain. (this is 4 all 4 motors)
I balanced the props and tested them on the quad and they all produced similar vibes and nothing major
I bought new arms in case some were twisted or something and still same issue.
Tightened all screws
I put it in Poshold and just watched the props for a couple minutes in hover and they looked fine
Frame: Aphid x450 (Uses f450 arms)
Sunnysky xx2212 980kv, 3S, 10x4.5sf plastic.