Martyn A Lewis

US Patent:

53195094, Jun 7, 1994

Filed:

Sep 13, 1991

Appl. No.:

7/759402

Inventors:

Gajus Michelson - Westlake Village CA
William W. Valliant - Camarillo CA
Martyn A. Lewis - Pacific Palisades CA

Assignee:

Servo Track Writer Corporation - Westlake Village CA

International Classification:

G11B 5596
G11B 3310

US Classification:

360 7703

Abstract:

A system and method for controlling and analyzing data storage systems, and more particularly, to systems and methods for controlling and analyzing performance and physical attributes of a sealed disk drive unit using an externally accessible but internally integral positioning system. A disk drive having a sealed housing utilizes a reflective planar mirror on the rotary actuator controlling the head drive assembly. A narrow beam directed through a window on the side wall of the housing onto the mirror is reflected off at angle dependent on the actuator position to a beam sensitive detector. A translator system driven by a positioner disposed at a distance from the rotary actuator axis which is substantially greater than the distance between the actuator axis and the head assembly, is used to vary the relationship between the directed and reflected beams. This system incorporates the rotary actuator in a closed loop servo that positions the actuator precisely at different locations relative to the recording medium, so that the data may be written and analyzed at off-track track position increments. The invention further provides, at an early or later manufacturing stage, means for calculating bias torque and friction without the need for prerecorded embedded servo information.

US Patent:

55109390, Apr 23, 1996

Filed:

Jul 16, 1992

Appl. No.:

7/915104

Inventors:

Martyn A. Lewis - Pacific Palisades CA

Assignee:

Micropolis Corporation - Chatsworth CA

International Classification:

G11B 5596

US Classification:

360 7809

Abstract:

A disk drive system with adaptive positioning employs one or more storage disks for recording data, one or more read and write heads for performing input/output operation on the disks, with at least one of the heads being used as a servo head, a head-positioning mechanism for controlling the movement of the heads, and a digital compensator for predicting the post-seek displacement of the heads due to internal accelerations and to provide a compensating control signal to the head-positioning mechanism. The compensator includes means for approximating an nth order transfer function and learning algorithms for adapting to the dynamic response characteristics of an individual disk drive unit. The positioning of the heads is adapted to minimize post-seek displacements through trial seeks executed at disk startup and continually through background processes performed during normal input/output operations.

US Patent:

48018538, Jan 31, 1989

Filed:

Nov 16, 1987

Appl. No.:

7/121200

Inventors:

Martyn Lewis - Pacific Palisades CA
Richard Anderson - Chatsworth CA

Assignee:

Eastman Kodak Company - Rochester NY

International Classification:

B65H 5938

US Classification:

318 7

Abstract:

A motion control system for a reel to reel web transport apparatus which maintains a controlled tension on a web as it is transported between reels. The motion control system includes brushless direct current motors directly coupled each reel. A magnetic hysteresis brake is coupled to each reel by means of respective one-way clutches. During transport of the web from reel to reel, a magnetic hysteresis brake applies a controlled torque only to the reel supplying web. Thus, a controlled tension is maintained on the web at all times, even during loss of power to the DC motors.

US Patent:

43719031, Feb 1, 1983

Filed:

Sep 28, 1981

Appl. No.:

6/305941

Inventors:

Martyn A. Lewis - Pacific Palisades CA

Assignee:

DMA Systems Corporation - Goleta CA

International Classification:

G11B 554
G11B 2102

US Classification:

360 75

Abstract:

In a disc drive including a disc having a magnetic surface and supported for rotation on a spindle, a spindle motor for driving the spindle, a linear motor having a positioner coil for radially moving a head support structure along the disc surface, and a circuit responsive to an emergency condition for causing the linear motor positioner coil to retract the head support structure, there is disclosed an improvement wherein the spindle motor is a rotating magnet DC motor and the kinetic energy stored in the rotating spindle mass is used to provide the energy required to unload the heads upon the occurrence of an emergency situation. Under emergency conditions, the spindle motor windings are switched directly to the linear motor positioner coil and the spindle motor acts as a generator to supply the head retract energy.

US Patent:

44245432, Jan 3, 1984

Filed:

Nov 16, 1981

Appl. No.:

6/321747

Inventors:

Martyn A. Lewis - Pacific Palisades CA
Steven K. Penniman - Goleta CA
David A. Sutton - Santa Ynez CA

Assignee:

DMA Systems Corporation - Goleta CA

International Classification:

G11B 582
G11B 2110
G11B 2108

US Classification:

360135

Abstract:

In a magnetic disc storage system and a magnetic disc therefor, the disc having opposed surfaces, at least one of the surfaces being coated with a magnetic material, the disc being adapted to be mounted on a spindle for rotation relative to a magnetic transducer positioned for recording data on and retrieving data from the disc, a plurality of concentric annular tracks being defined on the surface of the disc, each of the tracks being divided into a plurality of sectors, each sector having associated therewith prerecorded servo data for identification thereof, the improvement wherein the servo data for each sector comprises a unit distance track identification code recorded three times in succession, the code changing between adjacent sectors of adjacent tracks, and a clock shift check code recorded immediately following the last recorded one of the track identification codes, the same clock shift check code being recorded for each sector of every track.

US Patent:

54166527, May 16, 1995

Filed:

Aug 12, 1993

Appl. No.:

8/106400

Inventors:

Martyn A. Lewis - Pacific Palisades CA

Assignee:

Servo Track Writer Corporation - Westlake Village CA

International Classification:

G11B 509
G11B 5596

US Classification:

360 48

Abstract:

A head records a track (e. g. a servo track) in a memory member outside of a clean room without using reference indices. In each of a plurality of cyclical movements (e. g. revolutions), signals (e. g. servo signals) are recorded in the track in an individual number of frames. Thereafter th e distance of the unrecorded portion of the track is determined. In the next cyclical movement, the head records signals in an individual number of frames contiguous to the frames previously recorded, in a track distance dependent upon such individual number relative to the number of frames still unrecorded and upon the distance determined for the unrecorded track portion. In a last cyclical movement, the head records a single frame in a particular spatial relationship with the first and last frames. In a specific embodiment, 2. sup. N-K frames may be recorded in the K cyclical movement.

US Patent:

43718183, Feb 1, 1983

Filed:

Oct 15, 1980

Appl. No.:

6/197185

Inventors:

Martyn A. Lewis - Pacific Palisades CA

Assignee:

Minnesota Mining and Manufacturing Company - St. Paul MN

International Classification:

H02P 102

US Classification:

318313

Abstract:

A control system for a brushless direct current motor providing linear closed loop speed control when the motor is operating near its desired speed and providing pulse width modulation closed loop speed control when the motor is not operating near its desired speed. A current sensing feedback loop is provided to drive the transistor linearly controlling the electronic commutation of the motor into pulse width modulation when the current through the motor exceeds a predetermined value. An inductor may be coupled in series with control transistor and positive feedback may be supplied to the current sensor.

US Patent:

58548777, Dec 29, 1998

Filed:

Oct 16, 1996

Appl. No.:

8/732069

Inventors:

Martyn A. Lewis - Pacific Palisades CA

Assignee:

Seagate Technology, Inc. - Scotts Valley CA

International Classification:

G05B 1940

US Classification:

388812

Abstract:

A speed control system is disclosed wherein a brushless DC motor and a magneto resistive encoder are able to rotate a motor at arbitrarily low speeds. The motor is able to rotate at low speeds by having a filtered signal generated by an encoder applied to its inputs. The encoder is coupled to a series of filters which remove DC level and harmonic distortions from the resulting encoder signal. These filtered signals are then applied to the motor to control motor rotation speed.