Title:
ACTIVE DAMPING OF ACTUATOR BEARING TRANSLATIONAL MODE
Document Type and Number:
WIPO Patent Application WO/2001/001393
Kind Code:
A2
Abstract:
Apparatus and method for improving operational performance of a disc drive (100) by detecting and compensating for translational vibration modes in a disc drive actuator (110). The actuator (110) is configured to support a head (120) adjacent a recording disc (106) and pivots about a stationary shaft (132) by way of a cartridge bearing assembly (112) having a pair of ball bearing assemblies (140). A proximity probe (130) detects translational movement of the actuator assembly (110) relative to the shaft (132) due to, for example, abrupt acceleration and deceleration of the head (120) during a seek operation, or externally applied mechanical shocks. The output of the proximity probe is used to generate a bearing translation signal which is fed into an actuator control servo circuit (176) to modify the amount of current applied to an actuator motor (114) to compensate for the translational vibrations during track following and seek operations.
Inventors:
ALLSUP DAVID S
Application Number:
PCT/US2000/040295
Publication Date:
January 04, 2001
Filing Date:
June 30, 2000
Export Citation:
Assignee:
SEAGATE TECHNOLOGY LLC (US)
International Classes:
G11B5/54; F16C41/00; G11B5/55; G11B5/60; G11B21/02; G11B21/08; G11B21/10; G11B25/04; G11B33/08; H02P25/06; (IPC1-7): G11B5/00
Foreign References:
| EP0264535A2 | 1988-04-27 | |||
| US5610777A | 1997-03-11 | |||
| US5452612A | 1995-09-26 | |||
| US5426545A | 1995-06-20 | |||
| EP0560600A2 | 1993-09-15 |
Attorney, Agent or Firm:
Mccarthy, Randall K. (P.C. 1800 Mid-America Tower, 20 North Broadwa, Oklahoma City OK, US)
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Claims:
Claims:
| 1. | A disc drive comprising: a recordable disc upon which a plurality of tracks are radially defined; a rotary actuator having an Eblock which supports a head adjacent the disc; a bearing assembly having a stationary shaft and a bearing sleeve journaled about the shaft, wherein the bearing sleeve is rigidly affixed to the Eblock so that the actuator rotates about the bearing assembly; a proximity probe disposed adjacent the Eblock that generates a bearing translation signal representative of a change in the proximity of the Eblock relative to the proximity probe; an actuator motor coupled to the actuator; and a servo control circuit which applies current to the actuator motor to position the head in relation to servo signals generated as the head reads servo data stored on the disc, wherein the servo circuit further adjusts the current applied to the actuator motor in response to the bearing translation signal. |
| 2. | The disc drive of claim 1, wherein the proximity probe is disposed adjacent the stationary shaft within an interior of the bearing assembly. |
| 3. | The disc drive of claim 1, wherein the proximity probe is affixed to a mounting bracket disposed external to the actuator, and wherein the Eblock has a detection face which, in the absence of bearing translation, provides a constant proximity between the Eblock and proximity probe during rotation of the actuator. |
| 4. | The disc drive of claim 1, wherein the proximity probe comprises a capacitance probe. |
| 5. | The disc drive of claim 1, wherein the bearing translation signal is determined in relation to an error associated with measuring the bearing translation as the angular position of the rotary actuator changes during operation. |
| 6. | In a disc drive having a rotatable disc on which a plurality of tracks are defined, a rotary actuator which supports a head adjacent the disc, an actuator motor which rotates the actuator, a bearing assembly having a stationary shaft about which is journaled the rotary actuator, and a proximity probe disposed adjacent the bearing assembly that generates a bearing translation signal representative of a change in the proximity of the bearing assembly, a method for controlling the position of the head with respect to the disc, comprising steps of : (a) generating a base current command signal indicative of current to be applied to the actuator motor to position the head in a desired relation to the disc; (b) using the proximity probe to generate a bearing translation signal having a magnitude and direction indicative of a translation within the bearing assembly; (c) combining the base current command signal and the bearing translation signal to generate a modified current command signal; and (d) applying current to the actuator in response to the modified current command signal to position the head with respect to the disc. |
| 7. | The method of claim 6, wherein the method comprises a prior step of affixing the proximity probe to the stationary shaft within the interior of the bearing assembly. |
| 8. | The method of claim 6, wherein the method comprises a prior step of affixing the proximity probe to a mounting bracket disposed external to the bearing assembly. |
| 9. | The method of claim 6, wherein the proximity probe comprises a capacitance probe. |
Description:
INTERNATIONAL SEARCH REPORT International Application No PCT/US 00/40295 C. (Continuation) DOCUMENTS CONSIDERED TO BE RELEVANT Category ° Citation of document, with indication. where appropriate, of the relevant passages Relevant to claim No. A EP 0 560 600 A (MINISTOR 1 INTERNATI) 15 September 1993 (1993-09-15) column 5, line 19-column 7, line 20 1 INTERNATIONAL SEARCH REPORT International Application No Information on patent Samily members PCT/US 00/40295 Patent document Publication Patent family Publication cited in search report date member (s) date EP 0264535 A 27-04-1988 JP 63119076 A 23-05-1988 US 5610777 A 11-03-1997 JP 2516311 B 24-07-1996 JP 6309825 A 04-11-1994 US 5452612 A 26-09-1995 AU 3421593 A 28-07-1993 DE 69226519 D 10-09-1998 DE 69226519 T 04-02-1999 EP 0572657 A 08-12-1993 WO 9313426 A 08-07-1993 US 5426545 A 20-06-1995 NONE EP 0560600 A 15-09-1993 US 5333138 A 26-07-1994 JP 6187718 A 08-07-1994
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