Adaptive shock detection

• US 8,179,626 B1
• Filed: 12/04/2009
• Issued: 05/15/2012
• Est. Priority Date: 12/04/2009
• Status: Expired due to Fees

• Current Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Original Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Inventors: Ryan, Robert P., Brunnett, Don, Chahwan, Alain, Phan, Duc T.
• Primary Examiner(s): OLSON, JASON C
• Application Number:
  US12/631,716
• Time in Patent Office: 893 Days
• Field of Search: None
• US Class Current: 360/31
• CPC Class Codes: G11B 19/042 due to external shock or vibration
• CPC Class Codes: G11B 5/5582 system adaptation for working during or after external perturbation, e.g. in the presence of a mechanical oscillation caused by a shock

Abstract

Adaptive shock detection systems are provided according to various embodiments of the present invention. In one embodiment, an adaptive shock detection system comprises a shock sensing circuit, and a controller configured to receive shock detection signals from the shock sensing circuit and to dynamically adjust a sensitivity of the shock sensing circuit based the received shock detection signals.

Claims

1. An adaptive shock detection system, comprising:

a shock sensing circuit; and

a controller configured to receive shock detection signals from the shock sensing circuit and to dynamically adjust a sensitivity of the shock sensing circuit based on the received shock detection signals and to count a number of the shock detection signals from the shock sensing circuit over a first time window and to adjust the sensitivity of the shock sensing circuit based on the number of the shock detection signals,

wherein the first time window comprises two time periods of track following in a disk drive and excludes a time period of track seeking in the disk drive between the two time periods of the track following.

2. The system of claim 1, wherein the shock sensing circuit comprises:

a shock sensor; and

a comparator to receive a sensor signal based on an output signal from the shock sensor, to compare the sensor signal with a threshold, and to output a shock detection signal to the controller based on the comparison.

3. The system of claim 2, wherein the controller is configured to adjust the sensitivity of the shock sensing circuit by adjusting the threshold.

4. The system of claim 2, wherein the shock sensing circuit comprises an amplifier configured to amplify the sensor signal to the comparator, and wherein the controller is configured to adjust the sensitivity of the shock sensing circuit by adjusting a gain of the amplifier.

5. The system of claim 2, wherein the shock sensing circuit comprises a filter configured to filter the sensor signal to the comparator, and wherein the controller is configured to adjust the sensitivity of the shock sensing circuit by adjusting a bandwidth or transfer function of the filter.

6. The system of claim 2, wherein the controller is configured to measure a root mean square, a mean square error, or fast Fourier transform of the sensor signal and to adjust the sensitivity of the shock sensing circuit based on the root mean square, mean square error, or fast Fourier transform of the sensor signal.

7. The system of claim 1, wherein the controller is configured to determine a rate of the shock detection signals from the shock sensing circuit and to adjust the sensitivity of the shock sensing circuit based on the rate of the shock detection signals.

8. The system of claim 1, wherein the controller is configured to count a number of the shock detection signals from the shock sensing circuit over a first time window and to adjust the sensitivity of the shock sensing circuit based on the number of the shock detection signals, wherein the first time window is based on a period of time for reading servo sector information indicating wedges on a disk as the disk rotates.

9. The system of claim 8, wherein the controller is configured to decrease the sensitivity of the shock sensing circuit if the number of the shock detection signals over the first time window exceeds a first number.

10. The system of claim 9, wherein the controller is configured to count a number of the shock detection signals from the shock sensing circuit over a second time window and to increase the sensitivity of the shock sensing circuit if the number of the shock detection signals over the second time window is below a second number.

11. The system of claim 1, wherein the shock sensing circuit is configured to sense shocks within a disk drive.

12. The system of claim 1, wherein the controller is configured to abort a write operation when the controller receives a shock detection signal from the shock sensing circuit.

13. An adaptive shock detection system, comprising:

a shock sensing circuit; and

a controller configured to;

receive shock detection signals from the shock sensing circuit and to dynamically adjust a sensitivity of the shock sensing circuit based on the received shock detection signals,

count a number of the shock detection signals from the shock sensing circuit over a first time window and to adjust the sensitivity of the shock sensing circuit based on the number of the shock detection signals,

count a number of the shock detection signals from the shock sensing circuit over a second time window and to increase the sensitivity of the shock sensing circuit if the number of the shock detection signals over the second time window is below a second number, and

decrease the sensitivity of the shock sensing circuit if the number of the shock detection signals over the first time window exceeds a first number,

wherein the first time window comprises two time periods of track following in a disk drive and excludes a time period of track seeking in the disk drive between the two time periods of the track following, and wherein the second time window is longer than the first time window.

14. An adaptive shock detection system, comprising:

a shock sensing circuit configured to output first shock detection signals and second shock detection signals; and

a controller configured to;

receive the first and second shock detection signals from the shock sensing circuit,

abort write operations based on the first shock detections from the shock sensing circuit,

count a number of the second shock detection signals from the shock sensing circuit, and

dynamically adjust the sensitivity of the shock sensing circuit based at least on the number of the second shock detection signals.

15. The system of claim 14, wherein the shock sensing circuit has a first sensitivity setting for the first shock detection signals and a second sensitivity setting for the second shock detection signals, and the second sensitivity setting is higher than the first sensitivity setting.

16. A method for adaptively adjusting a shock sensing circuit, comprising:

receiving first shock detection signals and second shock detection signals from the shock sensing circuit;

aborting write operations based on the first shock detections from the shock sensing circuit;

counting a number of the second shock detection signals from the shock sensing circuit; and

adjusting a sensitivity of the shock sensing circuit based on the number of the received second shock detection signals.

17. The method of claim 16, wherein the adjusting the sensitivity of the shock sensing circuit comprises adjusting a threshold to a comparator of the shock sensing circuit.

18. The method of claim 16, wherein the adjusting the sensitivity of the shock sensing circuit comprises adjusting a gain of an amplifier of the shock sensing circuit.

19. The method of claim 16, wherein the adjusting the sensitivity of the shock sensing circuit comprises adjusting a bandwidth or a transfer function of a filter of the shock sensing circuit.

20. The method of claim 16, wherein the adjusting the sensitivity of the shock sensing circuit comprises:

determining a rate of the shock detection signals from the shock sensing circuit; and

adapting the shock sensing circuit based on the rate of the shock detection signals.

21. The method of claim 16, wherein the adjusting the sensitivity of the shock sensing circuit comprises:

counting a number of the shock detection signals from the shock sensing circuit over a first time window; and

adjusting the sensitivity of the shock sensing circuit based on the number of the shock detection signals.

22. The method of claim 21, wherein the adjusting the sensitivity of the shock sensing circuit based on the number of the shock detection signals comprises decreasing the sensitivity of the shock sensing circuit if the number of the shock detection signals over the first time window exceeds a first number.

23. The method of claim 22, further comprising:

counting a number of the shock detection signals from the shock sensing circuit over a second time window; and

increasing the sensitivity of the shock sensing circuit if the number of the shock detection signals over the second time window is below a second number.

24. A method for adaptively adjusting a shock sensing circuit, comprising:

receiving shock detection signals from the shock sensing circuit;

counting a number of the shock detection signals from the shock sensing circuit over a first time window and second time window, wherein the second time window is longer than the first time window; and

adjusting a sensitivity of the shock sensing circuit based on the received shock detection signals based on decreasing the sensitivity of the shock sensing circuit if the number of the shock detection signals over the first time window exceeds a first number and increasing the sensitivity of the shock sensing circuit if the number of the shock detection signals over the second time window is below a second number.