Comparison of the sliding observer to several state estimators using a rotational inverted pendulum

Because of the inherent characteristics of nonlinear systems, state estimation of these systems continues to pose difficult problems. The objective of this paper is to test the sliding mode observer technique on a highly nonlinear non-minimum phase system. The chosen system is the rotational inverted pendulum system of Misawa, Arrington, and Ledgerwood. In addition, the observer technique is compared to that of other techniques: the linear Kalman filter, Thau's method, the adaptive observer, the high gain observer, the multistage nonlinear observer, and the equivalent control-based sliding mode observer. The bases of comparison is performance, robustness against disturbances and modeling errors, stability, and ease of application.