Nonlinear systems Memes

Control theory professors: "You need complex mathematical proofs, robust H-infinity methods, and optimal control theory to handle nonlinear systems!" Industry engineers: "Haha PID controller go brrr." The dirty secret of engineering is that while academics write papers about sophisticated control algorithms, 98% of real-world industrial loops are controlled by the same basic PID controllers invented in 1922. Why solve for optimal actuation when you can just tweak three parameters until the machine stops exploding?