Internal model control (IMC) approach for designing disk drive servo-controller

Abstract

A design procedure for disk drive servomechanism using Internal Model Control (IMC) structure is presented. In this method, a second order nominal model of the plant is used to design an H2-optimal controller to attain minimum integral-error-square (ISE) performance. The H2-optimal control is augmented by a low pass filter with sufficient high-frequency roll-off to ensure robust stability and robust performance. A multiplicative uncertainty bound is defined using the data of the disk drive servo plant's frequency response and the response of the nominal model, and this is then used to decide robust stability and robust performance bounds. Simulation results for the design controller are presented.