ABSTRACT
This chapter introduces the conventional disturbance observer and presents a general form of disturbance observer. Disturbance observers can be used to increase the read/write head-positioning accuracy in hard disk drives by using its estimation results to cancel the effect of the disturbances and modeling error. A general form of disturbance observer has been presented and designed based on the H8 control method to achieve desired disturbance/noise rejection. The designed disturbance observer is applied to an hard disk drive servo system and its effectiveness in disturbance attenuation is demonstrated by simulations and experiments. A general form of disturbance observer has been presented and designed based on the H8 control method to achieve desired disturbance/noise rejection.
