Claims
- 1. In a hard disk drive having a plurality of disks, a method of compensating for offset between read/write heads nominally aligned with each other in a head stack positioned by a servo-controlled actuator, said method comprising the following steps:
- identifying a short seek command;
- initializing servo sample count to zero;
- adjusting estimated position of said heads with regard to said disks;
- adjusting seek length;
- calculating number of servo samples in which an acceleration pulse is applied;
- calculating number of servo samples in which a deceleration pulse is applied;
- calculating amplitude of acceleration pulses;
- calculating amplitude of deceleration pulses;
- incrementing servo error count by one; and
- adding feed forward into said servo-controlled actuator.
- 2. In a hard disk drive having a plurality of disks, and a plurality of read/write heads nominally aligned with each other in a head stack positioned by a servo-controlled actuator, a method of adaptively adjusting estimator position, feed forward durations and magnitudes based on identified head offsets, said method comprising the following steps:
- a adjusting the estimated position based on the head offset
- x.sub.1 =x.sub.1 +Offset.sub.mn
- b adjusting the seek length
- Seek.sub.-- length=Seek.sub.-- length--Offset.sub.mn
- c calculating the number of samples in which the acceleration pulse is applied
- N.sub.acceleration =round(A.sub.1 Seek.sub.-- length+B.sub.1)
- d calculating the number of samples in which the deceleration pulse is applied
- N.sub.deceleration =round(A.sub.2 Seek.sub.-- length+B.sub.2)
- e calculating the acceleration pulse amplitude
- V.sub.acceleration =A.sub.3 Seek.sub.-- length.sup.2 +B.sub.3 Seek.sub.-- length+C.sub.3
- f calculating the deceleration pulse amplitude
- V.sub.deceleration =A.sub.4 Seek.sub.-- length.sup.2 +B.sub.4 Seek.sub.-- length+C.sub.4
- g starting the seek using the feed forward specified by N.sub.acceleration, N.sub.deceleration, V.sub.acceleration, and V.sub.deceleration
- where:
- x.sub.1 =estimated position
- Offset.sub.mn =position offset between head m and head n
- Seek.sub.-- length=seek length
- N.sub.acceleration =the number of samples in which the acceleration pulse is applied
- round=rounding the expression to integer representation
- A.sub.1 to A.sub.4
- B.sub.1 to B.sub.4 =design constants which are selected based on servo loop parameters such as VCM parameters
- C.sub.3 to C.sub.4
- V.sub.acceleration =acceleration pulse amplitude
- N.sub.deceleration =the number of samples in which deceleration pulse is applied
- V.sub.deceleration =deceleration pulse amplitude.
Parent Case Info
This application is a division of application Ser. No. 08/606,641, filed Feb. 27, 1996, which is pending, which is a continuation of application Ser. No. 08/182,611 filed Jan. 14, 1994, now abandoned.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
4914644 |
Chen et al. |
Apr 1990 |
|
5602698 |
Kadlec |
Feb 1997 |
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Divisions (1)
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Number |
Date |
Country |
Parent |
606641 |
Feb 1996 |
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Continuations (1)
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Number |
Date |
Country |
Parent |
182611 |
Jan 1994 |
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