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Compensation Technique for External Vibration for Direct Access Storage Devices (DASD)

IP.com Disclosure Number: IPCOM000109045D
Original Publication Date: 1992-May-01
Included in the Prior Art Database: 2005-Mar-23
Document File: 1 page(s) / 45K

Publishing Venue

IBM

Related People

Nagarajan, S: AUTHOR

Abstract

A method for feedforward compensation for stable external vibration, applicable to DASD systems, is disclosed. With a prior knowledge of the frequencies of external vibration, we can perturb control signal parameters which include the magnitude, phase, and frequency, such that the position error signal is minimized.

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Compensation Technique for External Vibration for Direct Access Storage Devices (DASD)

      A method for feedforward compensation for stable external
vibration, applicable to DASD systems, is disclosed.  With a prior
knowledge of the frequencies of external vibration, we can perturb
control signal parameters which include the magnitude, phase, and
frequency, such that the position error signal is minimized.

      There are two ways of applying the compensation: 1) Using the
track-follow position error signal and a fourier transform technique,
we get the frequencies and amplitudes of the error.  Next we can pick
one, two, or more of the frequencies where the amplitudes are high.
The actuator is excited at one of the frequencies with a nominal
amplitude and a certain phase with respect to a known reference.
This excitation is termed as "control excitation," and the amplitude
of the frequency component in the position error signal is monitored.
The phase of the control is perturbed in convenient steps to obtain
that optimum phase for which the magnitude of that frequency
component in the position error signal is minimized.  In a similar
manner for the same phase, the magnitude and, then the frequency of
the control signal, are perturbed to determine all the main optimal
parameters of the control signal for which the position error signal
is minimized. 2) If the frequencies of the external vibration are
known beforehand, the analysis steps in the previous method ma...