Lan Anh Ngo

Address:

3434 Gln Vlg Ct, Orlando, FL 32822

VIN:

1HGCM82697A002630

Make:

HONDA

Model:

ACCORD

Year:

2007

US Patent:

6914743, Jul 5, 2005

Filed:

Nov 30, 2000

Appl. No.:

09/728626

Inventors:

Aswartha Narayana - Mission Viejo CA, US
Raffi Codilian - Irvine CA, US
Lan V. Ngo - Garden Grove CA, US

Assignee:

Western Digital Technologies, Inc. - Lake Forest CA

International Classification:

G11B005/596

US Classification:

360 7708, 360 7702, 360 7706

Abstract:

Disclosed is a disk drive using an accelerometer to sense linear vibration and cancel its effects with an adaptive algorithm during track following. The accelerometer is oriented to detect acceleration associated with torque that tends to cause the actuator to move off-track notwithstanding the efforts of the servo control system. The accelerometer's filtered output is used to modify the control effort. The disk drive uses the position error signal to adaptively filter the accelerometer's output in an effort to mathematically converge on a set of optimal filter coefficients and thereby reduce the effect of vibration that may otherwise impose a torque on the actuator.

US Patent:

6937423, Aug 30, 2005

Filed:

Feb 6, 2004

Appl. No.:

10/773526

Inventors:

Lan V. Ngo - Garden Grove CA, US
Raffi Codilian - Irvine CA, US

Assignee:

Western Digital Technologies, Inc. - Lake Forest CA

International Classification:

G11B005/596

US Classification:

360 7702, 360 7703, 360 7707

Abstract:

A method of reducing rotational vibration effects in a disk drive by sensing vibration in a sensor and generating corresponding sensor data; deriving a statistical sensor (SS) value based on the sensor data; deriving a statistical position error signal (SPES) value from servo sectors read by the head; comparing the SS value to a SS-threshold value; comparing SPES value to a SPES-threshold value; and generating a feed-forward command effort signal for reducing rotational vibration effects if the SS value exceeds the SS-threshold value and if SPES value exceeds the SPES-threshold value.

US Patent:

6952318, Oct 4, 2005

Filed:

Jan 30, 2004

Appl. No.:

10/769444

Inventors:

Lan V. Ngo - Garden Grove CA, US

Assignee:

Western Digital Technologies, Inc. - Lake Forest

International Classification:

G11B019/02

US Classification:

360 69

Abstract:

A method for reducing the effects of rotational vibration in a disk drive comprising generating a self-induced vibration in the disk drive, and sensing the self-induced vibration in the first and second sensors and generating a corresponding first and second sensor data. The method further comprises comparing the first and second sensor data to determine a gain-differential, and scaling at least one of the first and second sensor data to reduce the gain-differential between the first and second sensors.

US Patent:

7023640, Apr 4, 2006

Filed:

May 27, 2004

Appl. No.:

10/856400

Inventors:

Raffi Codilian - Irvine CA, US
Lan V. Ngo - Garden Grove CA, US
Norman D. Gardner - Aliso Viejo CA, US

Assignee:

Western Digital Technologies, Inc. - Lake Forest CA

International Classification:

G11B 19/04
G11B 21/02
G11B 19/02

US Classification:

360 60, 360 69, 360 75

Abstract:

A disk drive comprising a first sensor mounted on a nominally stationary portion of the disk drive and adapted to detect acceleration disturbances of the disk drive. The disk drive further comprising: a dual-function subsystem having a first circuit adapted to provide a write-inhibit signal and a second circuit adapted to provide a feed-forward basis signal, the dual-function subsystem adapted to receive a first sensor signal from the first sensor and to provide (a) the write-inhibit signal based on the received first sensor signal and a first threshold value, and (b) the feed-forward basis signal based on the received first sensor signal.

US Patent:

6710966, Mar 23, 2004

Filed:

Oct 23, 2001

Appl. No.:

10/003943

Inventors:

Raffi Codilian - Irvine CA
Aswartha Narayana - Mission Viejo CA
Lan V. Ngo - Garden Grove CA

Assignee:

Western Digital Technologies, Inc. - Lake Forest CA

International Classification:

G11B 5596

US Classification:

360 7708, 360 7702

Abstract:

The present invention may be embodied in a method, implemented in a disk drive, for adaptively reducing an effect of vibration during a track following operation. The disk drive includes a disk and a rotary actuator. The disk includes distributed position information in a plurality of servo wedges. The actuator carries a transducer and pivots on a base of the disk drive. The actuator may exhibit an imbalance that may be affected by a linear vibration. In the method, a sensor signal is generated that is responsive to a vibration to the disk drive. The sensor value is modified based on an adaptive-filter gain to generate a position error adjustment signal for modifying a nominal position error signal. The adaptive-filter gain is then altered based on an adjusted position error signal and the sensor value associated with the current servo wedge for use during a next servo wedge.