
Saunder January 22, 2014 10:43 K15053˙Book
Chapter 8
Nonlinear Disturbance
Observer-Based Control
for Systems with
Arbitrary Disturbance
Relative Degrees
8.1 Introduction
The nonlineardisturbance observer-based control(NDOBC) is proposedandfurther
researched by Chen and his colleagues [10, 2, 40, 5, 86]. It should be pointed out that
these results are only valid for the case where the disturbance relative degree (DRD) is
higher than or equal to the input relative degree (IRD) [10]. Disturbance attenuation
of nonlinear system with the DRD strictly lower than the IRD purely via a NDOBC
without resorting to a high-gain feedback-based design is a longstanding ...