On the improvement of transient performance in tracking control for discrete-time systems with input saturation and disturbances

Abstract

In this paper, we present an enhanced composite nonlinear feedback (CNF) control technique for discrete-time systems with input saturation and with external disturbances. The conventional CNF control is proved to be capable of yielding better transient performance in tracking control for systems with input saturation. However, when the given system has external disturbances as in most of practical situations, the conventional CNF control would yield some steady state errors in the resulting output response. The enhanced CNF technique presented is an extension of the conventional one. It retains good transient properties as those of the conventional CNF control and at the same time has an additional capacity of eliminating steady state bias due to unknown constant disturbances. © 2005 IEEE.