1. A method for controlling a non-linear plant, comprising the steps of: providing a linear controller having a linear gain k that is operable to receive inputs representing measured variables of the plant and predicting on an output of the linear controller predicted control values for manipulatible variables that control the plant; providing a non-linear model of the plant for storing a representation of the plant over a trained region of the operating input space and having a steady-state gain K associated therewith; adjusting the gain k of the linear model with the gain K of the non-linear model in accordance with a predetermined relationship as the measured variables change the operating region of the input space at which the linear controller is predicting the values for the manipulatible variables; and outputting the predictive manipulatible variables after the step of adjusting the gain k.