Dynamic magnetic information storage or retrieval – Automatic control of a recorder mechanism – Controlling the head
Reexamination Certificate
2008-05-20
2008-05-20
Nguyen, Hoa T. (Department: 2627)
Dynamic magnetic information storage or retrieval
Automatic control of a recorder mechanism
Controlling the head
Reexamination Certificate
active
11378459
ABSTRACT:
A disk drive has multiple feedforward controllers for handling external disturbances, such as rotational vibration (RV), that have different external disturbance frequency spectra. Each feedforward controller is designed to be optimal for a canceling a specific associated RV spectrum. The actual RV spectrum acting on the disk drive is determined and the proper feedforward controller is then selected and used to generate a compensation signal for canceling the RV. Each feedforward controller may be tested when the disk drive is experiencing the RV, and the resulting compensation signal and PES measured. The feedforward controller that produces the best external disturbance cancellation is then selected as the feedforward controller. A signal from a RV sensor may be used to detect the peak frequency of the actual RV spectrum. This detected peak frequency is then matched to a peak frequency in a plurality of peak frequencies in a lookup table, and the feedforward controller associated with the matching peak frequency is selected as the feedforward controller.
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Semba Tetsuo
Tzou Kevin I.
White Matthew T.
Berthold Thomas R.
Habermehl James L
Hitachi Global Storage Technologies - Netherlands B.V.
Nguyen Hoa T.
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