A self-tuning control scheme for disk file servos

Author

Horowitz, Roberto ; McCormick, James

Author_Institution

Dept. of Mech. Eng., California Univ., Berkeley, CA, USA

Volume

27

Issue

6

fYear

1991

fDate

11/1/1991 12:00:00 AM

Firstpage

4490

Lastpage

4495

Abstract

The authors present a self-tuning control scheme for disk file track-following servos. The scheme augments an existing fixed controller to recover a specified nominal performance in the presence of unmodeled dynamics. The compensator used in each disk file is individually tuned by inserting an add-on adjustable compensator to the nominal compensator, utilizing a linear fractional transformation (LFT) known as the Youla-Kucera parametrization. Similarly, the difference between the actual disk drive dynamics and the nominal model is characterized by an unknown transfer function, using the Youla-Kucera parametrization applied to the plant rather than the compensator. The algorithm consists of two steps: identification of the unmodeled dynamics transfer function, followed by the synthesis of the add-on compensator, utilizing the linear quadratic Gaussian (LQG) compensator methodology

Keywords

adaptive control; compensation; control system synthesis; magnetic disc storage; position control; self-adjusting systems; servomechanisms; transfer functions; Youla-Kucera parametrization; add-on compensator; disk drive dynamics; disk file servos; linear fractional transformation; linear quadratic Gaussian compensator methodology; self-tuning control scheme; track-following servos; transfer function; unmodeled dynamics; unmodeled dynamics transfer function; Control systems; Discrete time systems; Disk drives; Feedback; Laboratories; Mechanical engineering; Optimal control; Robust control; Servomechanisms; Transfer functions;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.278669

Filename

278669