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Numerically Efficient Estimator Structures for Dasd Digital Servo

IP.com Disclosure Number: IPCOM000036092D
Original Publication Date: 1989-Sep-01
Included in the Prior Art Database: 2005-Jan-28

Publishing Venue

IBM

Related People

Authors:
Ottesen, H Sri-Jayantha, M Stich, M [+details]

Abstract

The digital servos used in magnetic disk drives employ a state variable-based estimator/controller to achieve seek/tracking performance. The standard structure of a servo algorithm does not take advantage of the control law structure in order to reduce computation time and numerical round-off errors. A compressed form of the estimator/controller structure that reduces the number of multiplications by a factor of (1/n+3) and summations by (1+(1/n))/(n+2) is disclosed herein (where n is the model order of the combined estimator/ (Image Omitted) controller). The compression reduces the computation time as well as noise contribution due to multiplication-based round-off errors. The algorithm is valid only when the controller is linear, which is in fact the case in the track-following mode.