Saunder January 22, 2014 10:43 K15053˙Book
18 Disturbance Observer-Based Control: Methods and Applications
1.4 Early History
1.4.1 An Overview on Disturbance Estimation Approaches
Since 1970s, many effective disturbance estimation techniques have been developed,
such as Unknown Input Observer (UIO) [69], Perturbation Observer (PO) [70,
71], Equivalent Input Disturbance (EID)-based estimator [72, 73], Extended State
Observer (ESO) [74, 75, 4, 76], and Disturbance Observer (DO) [2, 27, 26, 28].
Among those disturbance estimation approaches, the theory and applications of DO
and ESO are most extensively investigated. ESO was firstly proposed by Prof. J. Han
in the 1990s [9]. ESO is generally regarded as a fundamental part of the so-called
active disturbance ...