Digital Equipment Corporation

Quantum Corporation

John A Scaramuzzo, Jr

Roger W Brockett

Frederick K Groll

Charles R Watt

A method and apparatus for moving a member provides parameters related to a given destination position of the member and corresponding to a switch time, a final time, an acceleration amplitude, and a deceleration amplitude. These parameters are used to specify a piecewise continuous function of time as an input signal. The input signal feeds a motor to move the member. The final time, switch time, acceleration amplitude, and deceleration amplitude are specified by iteratively providing minimal values for the switch time and final time while providing maximum acceptable values for the acceleration amplitude and deceleration amplitude for each possible given change in a characteristic of the movable member. A pre-shaped input signal is thereby provided which is bandwidth limited such that its energy is concentrated below the frequency of the lowest system resonance, since the signal is a piecewise continuous function comprising concatenated raised cosine and constant functions. The input signal may be asymmetrical and may have acceleration and deceleration amplitudes which differ in magnitude, and thus is useful in systems where it is desirable to the limit frequency content of an input signal while compensating for the effects of back EMF voltage. Since only four parameters are needed to specify the input signal, the signal is easy to construct, and it thus practical for use in high density disk drive applications.

Band limited control of a flexible structure using piecewise

A method for automatically calibrating gain parameters of a servo control including a track position detector for a computer disk drive. The method generally comprises the step of encoding AB bursts on at least one special calibration track of a disk surface in accordance with a known off center pattern signal having a preselected frequency. Servo correction number information is also encoded on the calibration track to compensate for the off center pattern of the AB bursts. A digital signal processing technique is performed on a correction signal derived from the AB bursts and servo correction number information to detect a residual signal at the preselected frequency of the off center pattern signal. The gain of the track position detector is thereafter adjusted to minimize the magnitude of the residual signal.

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Natick, MA, United States of America

John A Scaramuzzo, Jr