Gain scheduling control based on closed-loop system identification

Abstract

This paper deals with system identification and gain scheduling control of multi-variable nonlinear systems. We propose a novel scheme where a linear approximation of the system model is obtained in an operating point; then, a Youla-Kucera (YJBK) parameter specifying the difference between the first and a second operating point is identified in closed-loop using system identification methods with open-loop properties. Next, a linear controller is designed for this linearised model, and gain scheduling control can subsequently be achieved by interpolating between each controller. In a constructive manner, we show how to use the YJBK parameterisation to achieve a smooth scheduling between the controllers. The approach is tested on a simple, but highly nonlinear model of a coal-fired power plant.