PIFF controller in INAV is with us for quite some time now. And it's working just fine, much better than classic PID when it comes down to airplanes. There is, or rather was, a small problem tho: Iterm. When P and FF components of the controller are not tuned, Iterm might do crazy things that will surface themselves when you release the stick: airplane might either roll-back or do a follow-through.

In this video let's discuss why this is happening and what INAV 2.1 did to mitigate this problem. Because it did and it's called fw_iterm_limit_stick_position