[airbreather]

I built a fuzzy logic controller for a very large sag mill in a gold plant (top ten in the world by size).

But at the end of it managed to reduce it to a one line formula I could get almost identical results from when simulating in Excel.

I don't think this is an unusual case looking at other examples I found on the net - really it is just a form of non linear control and probably the easiest way to deal with a second order system that reverses action over the peak.