Design of multi-stage composite nonlinear feedback control for hard disk drives

Abstract

The multistage composite nonlinear feedback (MCNF) control is proposed to improve effectiveness of the composite nonlinear feedback (CNF) control. The latter is developed for a class of linear systems with actuator saturation and consists of a linear and a nonlinear feedback part without any switching element. There is another nonlinear feedback part added in the MCNF control compared to the CNF control. The added nonlinear feedback will be effective after the original one has been set to be linear and a new CNF control will be constructed. Experimental results show that the MCNF control can produce better performances than the CNF control to design hard disk drive (HDD) servo systems.