Implementation of a differential geometric nonlinear controller on an industrial evaporator system

Abstract This paper is devoted to the plant trial of a differential geometric nonlinear controller, input–output linearization(I/O), on the evaporative unit of the liquor burning process in an alumina Refinery. The liquor burning process is a two-input by two-output system with three nonlinear dynamic state equations. The trial is aimed at establishing guidelines for implementing I/O on site, including conversion of the relevant constraints and interface between the conventional industrial proportional and integral controller on site and the I/O nonlinear control algorithm. The results showed that the performance of the nonlinear controller was better at set point tracking while the existing feedforward ratio linear controller was less lively in terms of responsiveness, settling time, and resistance to both disturbances and set point changes.