Evert Cooper - Academia.edu (original) (raw)

Papers by Evert Cooper

Research paper thumbnail of Method and Apparatus for Controlling a Voice Coil Motor of a Hard Disk Drive

Research paper thumbnail of A United States Patent ( 19 ) 11 Patent Number : 6 , 091 , 567

73 Assignee: Seagate Technology, Inc., Scotts An apparatus and method are disclosed for improving... more 73 Assignee: Seagate Technology, Inc., Scotts An apparatus and method are disclosed for improving Servo Valley, Calif. performance of a disc drive. The disc drive includes a head adjacent a rotatable disc on which data are Stored on a 21 Appl. No.: 09/052,896 plurality of tracks. A Servo circuit is provided to control the position of the head by generating an actual (raw) position 22 Filed: Mar. 31, 1998 error Signal (PES) nominally characterized as nonlinear over O O a portion of the width of a selected track and indicative of Related U.S. Application Data position of the head relative to the selected track. The servo 60 Provisional application No. 60/071,158, Jan. 13, 1998. circuit further generates a predicted PES as an approxima (51) Int. Cl." ..................................................... G11B 5/596 tion of the actual PES, and then controls head position 52 U.S. Cl. ..................................... 360/77.08; 360/77.07; through Summation of the actual PES with ...

Research paper thumbnail of Electric switch operation monitoring circuitry

Research paper thumbnail of Modeling position error nonlinearity to improve servo performance

Research paper thumbnail of Control object positioning using an optimum jerk profile to reduce excitation of mechanical resonances

Research paper thumbnail of Singular Perturbation Time-Optimal Controller for Disk Drives

Optimal Control, 1993

One of the most important performance goals of a disk file actuator is rapid access time. The dis... more One of the most important performance goals of a disk file actuator is rapid access time. The disk file actuator as incorporated within its magnetic head/disk assembly is a high-order, flexible dynamic system with unpredictable behavior due to manufacturing tolerances and temperature variations. The controller must operate within demanding limits of response time, power consumption, and storage capacity. Although the goal of rapid access time argues for a time optimal control law, the high system order necessitates approximation techniques. Further, the desire to maintain near time-optimality in the presence of temperature fluctuations and time-varying unmodeled dynamic effects motivates the need for an adaptive approach. The disk drive control problem is summarized in Reference 1.

Research paper thumbnail of Perturbation method for improved time-optimal control of disk drives

Mechanics and Control, 1991

... Mark D. Ardema and Evert Cooper Santa Clara University~ Santa Clara, CA. 95053, USA 1. Introd... more ... Mark D. Ardema and Evert Cooper Santa Clara University~ Santa Clara, CA. 95053, USA 1. Introduction ... The time-optimal controller computes a control signal in real-time based on a reduced-order reference model of the true system. ...

Research paper thumbnail of Adaptive compensation for position error signal nonlinearity

IEEE Transactions on Magnetics, 2002

Research paper thumbnail of A nonlinearity specification for constructing the servo position error signal

IEEE Transactions on Magnetics, 1997

A high performance disk file actuator servo requires a position transducer whose response is line... more A high performance disk file actuator servo requires a position transducer whose response is linear with displacement. Two concerns that detrimentally affect positional linearity are the nonlinear response of the burst detector to burst amplitude and the nonuniform sensitivity of the magnetic read element across its pole faces. Nonuniform field sensitivity is of particular concern with the advent of magneto resistive heads for embedded servo systems, and this paper gives specification for both for good actuator positioning.

Research paper thumbnail of Accommodating errors in PES detection

IEEE Transactions on Magnetics, 1997

Research paper thumbnail of Minimizing power dissipation in a disk file actuator

IEEE Transactions on Magnetics, 1988

Research paper thumbnail of Design of a disk-file reference-velocity generator

IEEE Transactions on Magnetics, 1985

Research paper thumbnail of A disk file servomechanism immunized to media defects

IEEE Transactions on Magnetics, 1985

Research paper thumbnail of Minimum-time control of magnetic head flux

IEEE Transactions on Magnetics, 2001

This paper presents an optimal shape for a wave traversing a transmission line, incident to a mag... more This paper presents an optimal shape for a wave traversing a transmission line, incident to a magnetic head's write element, that gives minimum-time control of a magnetic head's yoke flux. The control waveform allows for the effects of the magnetic head's eddy currents as well as of the wave that reflects from the time-varying impedance of the magnetic head write

Research paper thumbnail of A solution to magnetic-bubble sensor-signal noise

IEEE Transactions on Magnetics, 1985

Research paper thumbnail of Method and Apparatus for Controlling a Voice Coil Motor of a Hard Disk Drive

Research paper thumbnail of A United States Patent ( 19 ) 11 Patent Number : 6 , 091 , 567

73 Assignee: Seagate Technology, Inc., Scotts An apparatus and method are disclosed for improving... more 73 Assignee: Seagate Technology, Inc., Scotts An apparatus and method are disclosed for improving Servo Valley, Calif. performance of a disc drive. The disc drive includes a head adjacent a rotatable disc on which data are Stored on a 21 Appl. No.: 09/052,896 plurality of tracks. A Servo circuit is provided to control the position of the head by generating an actual (raw) position 22 Filed: Mar. 31, 1998 error Signal (PES) nominally characterized as nonlinear over O O a portion of the width of a selected track and indicative of Related U.S. Application Data position of the head relative to the selected track. The servo 60 Provisional application No. 60/071,158, Jan. 13, 1998. circuit further generates a predicted PES as an approxima (51) Int. Cl." ..................................................... G11B 5/596 tion of the actual PES, and then controls head position 52 U.S. Cl. ..................................... 360/77.08; 360/77.07; through Summation of the actual PES with ...

Research paper thumbnail of Electric switch operation monitoring circuitry

Research paper thumbnail of Modeling position error nonlinearity to improve servo performance

Research paper thumbnail of Control object positioning using an optimum jerk profile to reduce excitation of mechanical resonances

Research paper thumbnail of Singular Perturbation Time-Optimal Controller for Disk Drives

Optimal Control, 1993

One of the most important performance goals of a disk file actuator is rapid access time. The dis... more One of the most important performance goals of a disk file actuator is rapid access time. The disk file actuator as incorporated within its magnetic head/disk assembly is a high-order, flexible dynamic system with unpredictable behavior due to manufacturing tolerances and temperature variations. The controller must operate within demanding limits of response time, power consumption, and storage capacity. Although the goal of rapid access time argues for a time optimal control law, the high system order necessitates approximation techniques. Further, the desire to maintain near time-optimality in the presence of temperature fluctuations and time-varying unmodeled dynamic effects motivates the need for an adaptive approach. The disk drive control problem is summarized in Reference 1.

Research paper thumbnail of Perturbation method for improved time-optimal control of disk drives

Mechanics and Control, 1991

... Mark D. Ardema and Evert Cooper Santa Clara University~ Santa Clara, CA. 95053, USA 1. Introd... more ... Mark D. Ardema and Evert Cooper Santa Clara University~ Santa Clara, CA. 95053, USA 1. Introduction ... The time-optimal controller computes a control signal in real-time based on a reduced-order reference model of the true system. ...

Research paper thumbnail of Adaptive compensation for position error signal nonlinearity

IEEE Transactions on Magnetics, 2002

Research paper thumbnail of A nonlinearity specification for constructing the servo position error signal

IEEE Transactions on Magnetics, 1997

A high performance disk file actuator servo requires a position transducer whose response is line... more A high performance disk file actuator servo requires a position transducer whose response is linear with displacement. Two concerns that detrimentally affect positional linearity are the nonlinear response of the burst detector to burst amplitude and the nonuniform sensitivity of the magnetic read element across its pole faces. Nonuniform field sensitivity is of particular concern with the advent of magneto resistive heads for embedded servo systems, and this paper gives specification for both for good actuator positioning.

Research paper thumbnail of Accommodating errors in PES detection

IEEE Transactions on Magnetics, 1997

Research paper thumbnail of Minimizing power dissipation in a disk file actuator

IEEE Transactions on Magnetics, 1988

Research paper thumbnail of Design of a disk-file reference-velocity generator

IEEE Transactions on Magnetics, 1985

Research paper thumbnail of A disk file servomechanism immunized to media defects

IEEE Transactions on Magnetics, 1985

Research paper thumbnail of Minimum-time control of magnetic head flux

IEEE Transactions on Magnetics, 2001

This paper presents an optimal shape for a wave traversing a transmission line, incident to a mag... more This paper presents an optimal shape for a wave traversing a transmission line, incident to a magnetic head's write element, that gives minimum-time control of a magnetic head's yoke flux. The control waveform allows for the effects of the magnetic head's eddy currents as well as of the wave that reflects from the time-varying impedance of the magnetic head write

Research paper thumbnail of A solution to magnetic-bubble sensor-signal noise

IEEE Transactions on Magnetics, 1985