Data storage device reducing seek power consumption
View Patent ↗A data storage device is disclosed comprising a disk comprising a plurality of tracks, a head, and an actuator configured to actuate the head over the disk. An adjusted seek time is determined to seek the head from a first track to a second track, and an adjusted coast velocity and an adjusted coast time of the seek is determined based on the adjusted seek time and a power consumption of the seek when a driving current applied to the actuator is substantially constant during at least one of an acceleration time and a deceleration time of the seek.
1. A data storage device comprising:
a disk comprising a plurality of tracks;
a head;
an actuator configured to actuate the head over the disk; and
control circuitry configured to:
determine an adjusted seek time to seek the head from a first track to a second track; and
determine an adjusted coast velocity and an adjusted coast time of the seek based on the adjusted seek time and a power consumption of the seek when a driving current applied to the actuator is substantially constant during at least one of an acceleration time and a deceleration time of the seek.
2. The data storage device as recited in claim 1 , wherein the control circuitry is further configured to determine the adjusted coast time t c2 based on:
t c2 =√{square root over ( T 2 2 −T 2 +t c 2 )}
where:
T represents a nominal seek time for the seek based on a nominal coast velocity and a nominal coast time t c ; and
T 2 represents the adjusted seek time.
3. The data storage device as recited in claim 2 , wherein the control circuitry is further configured to determine the adjusted coast velocity V c2 based on:
V
c
2
=
2
S
T
2
+
T
2
2
-
T
2
+
t
c
2
where S represents a distance of the seek.
4. The data storage device as recited in claim 1 , wherein the control circuitry is further configured to determine the adjusted coast time t c2 based on:
t
c
2
=
{
T
2
3
if
T
2
2
-
T
2
+
t
c
2
≥
(
T
2
3
)
2
and
T
2
3
>
t
c
-
t
la
T
2
2
-
T
2
+
t
c
2
if
(
T
2
2
-
T
2
+
t
c
2
)
<
(
T
2
3
)
2
t
c
-
t
la
Otherwise
where:
T represents a nominal seek time for the seek based on a nominal coast velocity and a nominal coast time t c ; and
T 2 represents the adjusted seek time; and
t la represents a difference between T 2 and T.
5. The data storage device as recited in claim 4 , wherein the control circuitry is further configured to determine the adjusted coast velocity V c2 based on:
V
c
2
=
{
3
S
2
T
2
if
T
2
2
-
T
2
+
t
c
2
≥
(
T
2
3
)
2
and
T
2
3
>
t
c
-
t
la
2
S
T
2
+
T
2
2
-
T
2
+
t
c
2
if
(
T
2
2
-
T
2
+
t
c
2
)
<
(
T
2
3
)
2
V
c
Otherwise
where S represents a distance of the seek.
6. The data storage device as recited in claim 5 , wherein the control circuitry is further configured to determine an adjusted driving current a 2 of the adjusted seek time based on:
a
2
=
{
a
1
*
9
8
*
T
2
-
t
c
2
T
2
2
if
T
2
2
-
T
2
+
t
c
2
≥
(
T
2
3
)
2
and
T
2
3
>
t
c
-
t
la
a
1
if
(
T
2
2
-
T
2
+
t
c
2
)
<
(
T
2
3
)
2
a
1
*
T
-
t
c
T
2
-
t
c
+
t
la
Otherwise
where T represents a nominal seek time for the seek based on a nominal coast velocity, a nominal coast time t c , and a nominal driving current a 1 .
7. The data storage device as recited in claim 6 , wherein a 2 ≦a 1 .
8. The data storage device as recited in claim 1 , wherein the control circuitry is further configured to determine a seek parameter based on the adjusted coast time and the adjusted coast velocity.
9. The data storage device as recited in claim 8 , wherein the control circuitry is further configured to determine the seek parameter based on an adjusted driving current corresponding to the adjusted coast time and the adjusted coast velocity.
10. A method of operating a data storage device, the method comprising:
determining an adjusted seek time to seek a head from a first track to a second track on a disk; and
determining an adjusted coast velocity and an adjusted coast time of the seek based on the adjusted seek time and a power consumption of the seek when a driving current applied to an actuator is substantially constant during at least one of an acceleration time and a deceleration time of the seek.
11. The method as recited in claim 10 , further comprising determining the adjusted coast time t c2 based on:
t c2 =√{square root over ( T 2 2 −T 2 +t c 2 )}
where:
T represents a nominal seek time for the seek based on a nominal coast velocity and a nominal coast time t c ; and
T 2 represents the adjusted seek time.
12. The method as recited in claim 11 , further comprising determining the adjusted coast velocity V c2 based on:
V
c
2
=
2
S
T
2
+
T
2
2
-
T
2
+
t
c
2
where S represents a distance of the seek.
13. The method as recited in claim 10 , further comprising determining the adjusted coast time t c2 based on:
t
c
2
=
{
T
2
3
if
T
2
2
-
T
2
+
t
c
2
≥
(
T
2
3
)
2
and
T
2
3
>
t
c
-
t
la
T
2
2
-
T
2
+
t
c
2
if
(
T
2
2
-
T
2
+
t
c
2
)
<
(
T
2
3
)
2
t
c
-
t
la
Otherwise
where:
T represents a nominal seek time for the seek based on a nominal coast velocity and a nominal coast time t c ; and
T 2 represents the adjusted seek time; and
t la represents a difference between T 2 and T.
14. The method as recited in claim 13 , further comprising determining the adjusted coast velocity V c based on:
V
c
2
=
{
3
S
2
T
2
if
T
2
2
-
T
2
+
t
c
2
≥
(
T
2
3
)
2
and
T
2
3
>
t
c
-
t
la
2
S
T
2
+
T
2
2
-
T
2
+
t
c
2
if
(
T
2
2
-
T
2
+
t
c
2
)
<
(
T
2
3
)
2
V
c
Otherwise
where S represents a distance of the seek.
15. The method as recited in claim 14 , further comprising determining an adjusted driving current a 2 of the adjusted seek time based on:
a
2
=
{
a
1
*
9
8
*
T
2
-
t
c
2
T
2
2
if
T
2
2
-
T
2
+
t
c
2
≥
(
T
2
3
)
2
and
T
2
3
>
t
c
-
t
la
a
1
if
(
T
2
2
-
T
2
+
t
c
2
)
<
(
T
2
3
)
2
a
1
*
T
-
t
c
T
2
-
t
c
+
t
la
Otherwise
where T represents a nominal seek time for the seek based on a nominal coast velocity, a nominal coast time t c , and a nominal driving current a 1 .
16. The method as recited in claim 15 , wherein a 2 ≦a 1 .
17. The method as recited in claim 10 , further comprising determining a seek parameter based on the adjusted coast time and the adjusted coast velocity.
18. The method as recited in claim 17 , further comprising determining the seek parameter based on an adjusted driving current corresponding to the adjusted coast time and the adjusted coast velocity.