Disk drive pivot nonlinearity modeling and compensation through fuzzy logic

The pivot nonlinearity of a disk drive actuator is a complex phenomenon. Various models and compensation schemes were designed to cope with the nonlinearity. In this paper, a fuzzy logic based actuator pivot nonlinearity model is proposed. The fuzzy model can learn the dynamics of the actuator pivot nonlinearity by training with measured data. After the fuzzy model is trained, it can be augmented into a servo controller design as a disturbance observer to cancel the effects of the pivot nonlinearity. The fuzzy model, its modeling performance and a laboratory implementation to demonstrate its effectiveness in pivot nonlinearity compensation are presented.