Granted Patent B1

US 9,053,726 · App. 14/179,268 · Granted Jun 9, 2015

Abstract

Claims (204)

1. A data storage device comprising:

a disk comprising tracks defined by servo sectors;

a head; and

control circuitry configured to:

measure a location of the head over the disk based on the servo sectors;

generate a position error signal (PES) representing a difference between a target location for the head and the measured location for the head;

generate an actuator control signal (ACS) in response to the PES;

generate a disturbance compensation signal (DCS) based on the PES and the ACS;

filter the DCS with a disturbance observer filter;

adjust the ACS based on an output of the disturbance observer filter;

actuate the head over the disk based on the adjusted ACS;

filter the DCS with a plurality of band-pass filters different from the disturbance observer filter; and

adjust the disturbance observer filter based on the plurality of band-pass filters.

2. The data storage device as recited in claim 1 , wherein the control circuitry is further configured to adjust the disturbance observer filter by adjusting at least one of a center frequency, a gain, and a bandwidth of the disturbance observer filter.

3. The data storage device as recited in claim 2 , wherein the control circuitry is further configured to adjust the gain of the disturbance observer filter according to:

min

(

1

,

max

(

G

min

,

(

1

-

G

min

)

⁢

mag

pk

-

MLMG

MLFG

-

MLMG

+

G

min

)

)

where:

G min represents a minimum gain;

mag pk represents a magnitude of an output of one of the band-pass filters;

MLMG represents a magnitude level of minimum gain; and

MLFG represents a magnitude level of full gain.

4. The data storage device as recited in claim 1 , wherein each of the band-pass filters comprises a gain based on a torque sensitivity function of the control circuitry.

5. A data storage device comprising:

a disk comprising tracks defined by servo sectors;

a head; and

control circuitry configured to:

measure a location of the head over the disk based on the servo sectors;

generate a position error signal (PES) representing a difference between a target location for the head and the measured location for the head;

generate an actuator control signal (ACS) in response to the PES;

generate a disturbance compensation signal (DCS) based on the PES and the ACS;

filter the DCS with a disturbance observer filter;

adjust the ACS based on an output of the disturbance observer filter and adjust at least one of a center frequency, a gain, and a bandwidth of the disturbance observer filter;

actuate the head over the disk based on the adjusted ACS; and

filter the adjusted ACS with a loop shaping filter comprising a plurality of second-order filters:

∏

i

⁢

⁢

A

i

⁡

(

z

-

1

)

B

i

⁡

(

z

-

1

)

.

6. The data storage device as recited in claim 5 , wherein the control circuitry is further configured to adjust the disturbance observer filter based on the DCS.

7. The data storage device as recited in claim 5 , wherein the control circuitry is further configured to adjust the at least one of the center frequency, the gain, and the bandwidth of the disturbance observer filter based on a frequency response of the DCS.

8. The data storage device as recited in claim 5 , wherein the control circuitry is further configured to actuate the head over the disk based on an output of the loop shaping filter.

9. A method of operating a data storage device, the method comprising:

measuring a location of a head over a disk based on servo sectors on the disk;

generating a position error signal (PES) representing a difference between a target location for the head and the measured location for the head;

generating an actuator control signal (ACS) in response to the PES;

generating a disturbance compensation signal (DCS) based on the PES and the ACS;

filtering the DCS with a disturbance observer filter;

adjusting the ACS based on an output of the disturbance observer filter;

actuating the head over the disk based on the adjusted ACS;

filtering the DCS with a plurality of band-pass filters different from the disturbance observer filter; and

adjusting the disturbance observer filter based on the plurality of band-pass filters.

10. The method as recited in claim 9 , further comprising adjusting the disturbance observer filter by adjusting at least one of a center frequency, a gain, and a bandwidth of the disturbance observer filter.

11. The method as recited in claim 10 , further comprising adjusting the gain of the disturbance observer filter according to:

min

(

1

,

max

(

G

min

,

(

1

-

G

min

)

⁢

mag

pk

-

MLMG

MLFG

-

MLMG

+

G

min

)

)

where:

G min represents a minimum gain;

mag pk represents a magnitude of an output of one of the band-pass filters;

MLMG represents a magnitude level of minimum gain; and

MLFG represents a magnitude level of full gain.

12. The method as recited in claim 9 , wherein each of the band-pass filters comprises a gain based on a torque sensitivity function of the data storage device.

13. A method of operating a data storage device, the method comprising:

measuring a location of a head over a disk based on servo sectors on the disk;

generating a position error signal (PES) representing a difference between a target location for the head and the measured location for the head;

generating an actuator control signal (ACS) in response to the PES;

generating a disturbance compensation signal (DCS) based on the PES and the ACS;

filtering the DCS with a disturbance observer filter;

adjusting the ACS based on an output of the disturbance observer filter and concurrently adjusting at least one of a center frequency, a gain, and a bandwidth of the disturbance observer filter;

actuating the head over the disk based on the adjusted ACS; and

filtering the adjusted ACS with a loop shaping filter comprising a plurality of second-order filters:

∏

i

⁢

⁢

A

i

⁡

(

z

-

1

)

B

i

⁡

(

z

-

1

)

.

14. The method as recited in claim 13 , further comprising adjusting the disturbance observer filter based on the DCS.

15. The method as recited in claim 13 , further comprising adjusting the at least one of the center frequency, the gain, and the bandwidth of the disturbance observer filter based on a frequency response of the DCS.

16. The method as recited in claim 13 , further comprising actuating the head over the disk based on an output of the loop shaping filter.

17. Control circuitry configured to:

measure a location of a head over a disk based on servo sectors on the disk;

generate a position error signal (PES) representing a difference between a target location for the head and the measured location for the head;

generate an actuator control signal (ACS) in response to the PES;

generate a disturbance compensation signal (DCS) based on the PES and the ACS;

filter the DCS with a disturbance observer filter;

adjust the ACS based on an output of the disturbance observer filter;

actuate the head over the disk based on the adjusted ACS;

filter the DCS with a plurality of band-pass filters different from filtering the DCS with the disturbance observer filter; and

adjust the disturbance observer filter based on the plurality of band-pass filters.

18. Control circuitry configured to:

measure a location of a head over a disk based on servo sectors on the disk;

generate a position error signal (PES) representing a difference between a target location for the head and the measured location for the head;

generate an actuator control signal (ACS) in response to the PES;

generate a disturbance compensation signal (DCS) based on the PES and the ACS;

filter the DCS with a disturbance observer filter;

adjust the ACS based on an output of the disturbance observer filter and adjust at least one of a center frequency, a gain, and a bandwidth of the disturbance observer filter;

actuate the head over the disk based on the adjusted ACS; and

filter the adjusted ACS with a loop shaping filter comprising a plurality of second-order filters:

∏

i

⁢

⁢

A

i

⁡

(

z

-

1

)

B

i

⁡

(

z

-

1

)

.

Assignments (8)