Systems, apparatus, and methods for motor control

• US 6,977,477 B2
• Filed: 11/27/2001
• Issued: 12/20/2005
• Est. Priority Date: 11/27/2000
• Status: Expired due to Fees

• Current Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Original Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Inventors: Hastings, Matthew E., Bloyer, Donald Ray, Korbel, Garry E.
• Primary Examiner(s): Martin, David
• Assistant Examiner(s): MILLER, PATRICK L
• Application Number:
  US09/995,433
• Publication Number:
  US 20020063545A1
• Time in Patent Office: 1,484 Days
• Field of Search: 318/560, 318/638, 318/685, 318/696, 318/565, 388/806, 388/815, 388/833, 388/847, 369/30.22, 369/30.24, 369/30.36, 369/44.32, 369/44.33, 369/44.34, 369/47.44, 369/52.1
• US Class Current: 318/560
• CPC Class Codes: G11B 19/28 Speed controlling, regulating, or indicating G11B19/24 takes precedence
• CPC Class Codes: Y10S 388/902 Compensation

Abstract

Systems and methods are provided through which the current to a spindle motor of the recording medium of a mass storage device is modulated to avoid anomalies in the operation of mass storage device and reduce power consumption. In the example of a disc drive, the current is modulated to prevent expected or predicted disturbances in the air bearing between a read/write head and the recording medium, and to reduce the power consumption when no disturbances are predicted or expected.

Claims

1. A method comprising steps of:

(a) directing current to a motor; and

(b) modulating the current in reference to a predetermined profile that reduces air bearing instability, and in reference to an occurrence of interference associated with an undesired air-bearing stability in an interface between a head and a surface.

2. The method of claim 1, wherein the motor is associated with a spindle and the surface is a disc, wherein the disc and motor are included in a storage device.

3. The method of claim 2, wherein the modulating step (b) further comprises the step of:

(b)(i) modulating the current in reference to a predicted occurrence of interference in the interface between the head and the disc of the storage device that exceeds a predetermined threshold of interference in the interface between the head and the disc of the storage device.

4. The method of claim 3, wherein the modulating step (b)(i) further comprises the steps of:

(b)(i)(1) monitoring a lapse of time;

(b)(i)(2) comparing the lapse of time to the time of a predicted occurrence of interference in the interface between the head and the disc of the storage device that exceeds a predetermined threshold of interference in the interface between the head and the disc of the storage device; and

(b)(i)(3) modulating the current in reference to the predicted occurrence.

5. The method of claim 2 wherein the modulating step (b) further comprises the step of:

(b)(i) modulating the current during spin-up of the storage device.

6. The method of claim 2, wherein the modulating step (b) further comprises the step of:

(b)(i) modulating the current during spin-down of the storage device.

7. The method of claim 1, wherein the profile represents a relationship between time and quantity of current, and wherein the modulating step further comprises the steps of:

(b)(1) monitoring a lapse of time;

(b)(2) referencing the representation of a quantity of current in the profile, from the lapse of time; and

(b)(3) modulating the current to the motor in reference to the representation of the quantity of current in the profile.

8. The method of claim 1, wherein the

predetermined profile reduces takeoff air-bearing instability.

9. The method of claim 1, wherein the modulating step (b) further comprises the step of:

(b)(i) increasing the current, in reference to the occurrence of interference in the interface between the head and the surface.

10. A method for generating a profile of modulated current of a spindle motor of a mass storage device, the method comprising steps of:

(a) receiving air-bearing stability performance data of the mass storage device, the data including the quantity of current applied to the spindle motor at a plurality of discrete points in time, and including at least one performance measurement;

(b) determining a portion of the performance data that indicates a performance inadequacy that exceeds a predetermined threshold; and

(c) generating the profile in reference to the performance inadequacy and the performance data.

11. The method of claim 10, wherein the air-bearing stability further comprises takeoff air-bearing stability.

12. The method of claim 10, wherein the performance data includes a measurement of a drag and a measurement of speed, and the method further comprises:

(d) measuring the drag and speed; and

(e) burning the profile into the firmware of a processor of the mass storage device.

13. A method for dynamically modulating current based on dynamic performance data during operation of a storage device, the method comprising steps of:

(a) determining interference associated with an undesired air-bearing stability between a head and a storage medium of the storage device, in reference to a performance profile, and in reference to dynamic performance data during operation, the determining step comprising;

(a)(i) measuring the time per revolution; and

(a)(ii) comparing the time per revolution to an expected time in the profile;

wherein not meeting the expected time is an indication of interference; and

(b) modulating current to control the disc in reference to the interference.

14. A method for dynamically modulating current based on dynamic performance data during operation of a storage device, the method comprising steps of:

(a) determining interference associated with an undesired air-bearing stability between a head and a storage medium of the storage device, in reference to a performance profile, and in reference to dynamic performance data during operation, the determining step comprising;

(a)(i) sampling the rate of change of speed; and

(a)(ii) comparing the rate of change of speed to a last sample; and

(b) modulating current to control the disc in reference to the interference.

15. The method of claim 14, wherein the sampling step (a)(i) further comprises:

(a)(i)(1) sampling the rate of change of speed at each revolution.

16. The method of claim 14, wherein the sampling step (a)(i) further comprises:

(a)(i)(1) sampling the rate of change of speed at multiple revolutions.

17. The method of claim 14, wherein the sampling step (a)(i) further comprises:

(a)(i)(1) sampling the rate of change of speed at sub-multiple revolutions.

18. An apparatus for controlling a spindle motor of a mass storage device, the apparatus comprising:

a recording medium;

a spindle motor operably attached to the recording medium of the mass storage device; and

a modulator that modulates current to the spindle motor in a manner that avoids anomalies in the performance of the mass storage device thereby reducing wear on a head and the recording medium, the modulator being operably coupled to the spindle motor.

19. The apparatus of claim 18, further comprising:

a predetermined profile, the profile including a plurality of representations of quantity of current and a corresponding plurality of times.

20. The apparatus of claim 19, wherein the modulator further comprises:

a clock device, wherein the clock device is a component of a microcontroller of the mass storage device;

a time monitor of a lapse of time, wherein the time monitor obtains the time from the clock device, and generates a time lapse from the time, the time monitor being operably coupled to the clock device;

a profile referencer, wherein the profile reference references the predetermined profile using the lapse of time to extract or receive a representation of a quantity of current in the profile, the profile referencer operably coupled to the time monitor; and

a controller of the current to the spindle motor in reference to the representation of the quantity of current, the controller operably coupled to the profile referencer.

21. The apparatus of claim 20, wherein the profile referencer identifies a particular quantity or level of current from the lapse of time as an index into the profile.

22. The apparatus of claim 20, wherein the mass storage device further comprises a disc drive.

23. An apparatus to generate a profile of modulated current of a spindle motor of a mass storage device, comprising:

a receiver of performance data of the mass storage device, wherein the data includes a quantity of current applied to the spindle motor at each of a plurality of discrete points in time, and wherein the data also includes at least one air-bearing stability performance measurement;

a determiner of one or more portions of the performance data that indicate a performance inadequacy that exceeds a predetermined threshold or level, wherein the determiner is operably coupled to the receiver, and

a generator of the profile in reference to the performance inadequacy and the performance data, wherein the generator is operably coupled to the determiner.