A Comparison Study of Nonlinear State Observer Design: Application to an Intensified Heat-Exchanger/Reactor

In this paper, five classical nonlinear state observers: extended Luenberger observer (ELO), extended Kalman filter (EKF), high-gain observer (HGO), sliding mode observer (SMO) and adaptive observer (AO), are applied to an intensified chemical heat exchanger/reactor (HEX reactor). In order to choose a suitable observer to develop a new fault diagnosis algorithm for this high nonlinear system, the behaviors of these observers are compared. The maximum overshoot and the settling time, which are the key features of the dynamic of the output estimation error system, are used as the criteria to compare the performances of the observers. Both cases with and without measurement noise are considered. It is concluded that the AO presents the fastest convergence speed and the minimum oscillation for the application to the HEX reactor. And the information provided by the AO will be further used for its fault diagnosis.