Head positioning control system for use in a disk drive using different target velocity data for read and write seeks

• US 6,002,544 A
• Filed: 08/26/1997
• Issued: 12/14/1999
• Est. Priority Date: 12/27/1996
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Yatsu, Masahide
• Primary Examiner(s): Psitos, Aristotelis M.
• Assistant Examiner(s): HABERMEHL, JAMES LEE
• Application Number:
  US08/918,319
• Time in Patent Office: 840 Days
• Field of Search: 360/78.07, 360/75, 360/78.04, 360/78.06
• US Class Current: 360/78.09
• CPC Class Codes: G11B 21/083 on discs
• CPC Class Codes: G11B 5/5547 "Seek" control and circuits therefor G11B5/5556 takes precedence
• CPC Class Codes: G11B 5/59688 Servo signal format patterns or signal processing thereof, e.g. dual, tri, quad, burst signal patterns

Abstract

A head positioning control system for use in a HDD and arranged to position a head in a target position has different seek control systems arranged to be operated respectively when a read access is made and when a write access is made. When the read access is made, the system using target velocity data for controlling read seek executes read seek control. When the write access is made, the system using target velocity data for controlling write seek executes write seek control. The read seek control allows the head to be moved to the target position at relatively high velocity. The write seek control allows the head to relatively stably and accurately reach the target position.

Claims

1. A head positioning control system for positioning a head in a target position on a disk based on a servo data prerecorded on the disk, the system comprising:

read seek control means for controlling and moving the head to the target position in accordance with prerecorded target velocity data for the read seek when a read access is made;

write seek control means for controlling and moving the head to the target position in accordance with prerecorded target velocity data for the write seek when a write access is made; and

write seek control means uses target velocity data for controlling the write seek having a precise accuracy characteristic to execute seek control in such a manner that the head is moved to a relatively narrow allowable range for the target position as compared with an allowable range for use when the read access is made on the assumption that the movement distance to the target position is the same.

2. A head positioning control system for positioning a head in a target position on a disk based on a servo data prerecorded on the disk, the system comprising:

read seek control means for controlling and moving the head to the target position in accordance with prerecorded target velocity data for the read seek when a read access is made;

write seek control means for controlling and moving the head to the target position in accordance with prerecorded target velocity data for the write seek when a write access is made; and

target velocity data for controlling the read seek and target velocity data for controlling the write seek have the velocity characteristics for controlling movement of the head, the velocity characteristics including the same target velocity for use in an acceleration mode and a constant velocity mode and different target velocity for use in a deceleration mode which is employed when the head has approached a target position.

3. A head positioning control system for positioning a head in a target position on a disk based on a servo data prerecorded on the disk, the system comprising:

read seek control means for controlling and moving the head to the target position in accordance with prerecorded target velocity data for the read seek when a read access is made;

write seek control means for controlling and moving the head to the target position in accordance with prerecorded target velocity data for the write seek when a write access is made;

read seek control means includes means for executing read position control which uses target position locus data having a high velocity characteristic to position the head in the allowable range for the target position after the head has approached the target position; and

the write seek control means includes means for executing write position control which uses target position locus data having a precise accuracy characteristic to position the head in a relatively narrow allowable range for the target position as compared with an allowable range for use when the read access is made.

4. A head positioning control system for positioning a head in a target position on a disk based on a servo data prerecorded on the disk, the system comprising:

read seek control means for controlling and moving the head to the target position in accordance with prerecorded target velocity data for the read seek when a read access is made;

write seek control means for controlling and moving the head to the target position in accordance with prerecorded target velocity data for the write seek when a write access is made;

each of target velocity data items for respectively controlling the read seek and the write seek has a velocity characteristic composed of an acceleration mode, a constant speed mode and a deceleration mode; and

target velocity data for controlling the write seek is arranged in such a such a manner that start time of the deceleration mode is earlier than start time of the deceleration mode indicated by target velocity data for controlling the read seek.

5. In a disk drive having a head, a disk and a head positioning control system for positioning the head in a target position on the disk based on a servo data prerecorded on the disk, the head positioning control system comprising:

determining means for determining read seek control for moving the head to the target position when a read access is made to read data by the head from the target position on the disk or write seek control for moving the head to the target position when a write access is made to write data on the target position;

detecting means for detecting the position of the head in accordance with servo data read by the head;

memory means for previously storing target velocity data for controlling the read seek and target velocity data for controlling the write seek;

means for selectively reading target velocity data for controlling the read seek from the memory means when the read seek control is performed and for selectively reading target velocity data for controlling the write seek from the memory means when the write seek control is performed;

read seek control means for executing the read seek control by transmitting an amount of a control operation corresponding to the difference in the velocity between velocity indicated by target velocity data for controlling the read seek selected from the memory means and movement velocity obtained in accordance with the position of the head detected by the detecting means;

write seek control means for executing the write seek control by transmitting an amount of a control operation corresponding to the difference in the velocity between velocity indicated with target velocity data for controlling the write seek selected from the memory means and movement velocity obtained in accordance with the position of the head detected by the detecting means;

driving means for moving the head to the target position at the velocity determined in accordance with the amount of the control operation transmitted from the read seek control means or the write seek control means;

memory means stores target velocity data having a high velocity characteristic as compared with target velocity data for controlling the write seek to use as target velocity data for controlling the read seek and stores target velocity data having a precise accuracy characteristic as compared with target velocity data for controlling the read seek to use as target velocity data for controlling the write seek;

the read seek control means uses target velocity data for controlling the read seek to execute seek control in such a manner that seek time taken for the head to be moved to the target position is relatively short as compared with time taken when the write seek control is performed; and

the write seek control means uses target velocity data for controlling the write seek to execute the seek control in such a manner that the head is moved to a relatively narrow allowable range for the target position as compared with an allowable range for use when the read seek control is performed.

6. In a disk drive having a head, a disk and a head positioning control system for positioning the head in a target position on the disk based on a servo data prerecorded on the disk, the head positioning control system comprising:

determining means for determining read seek control for moving the head to the target position when a read access is made to read data by the head from the target position on the disk or write seek control for moving the head to the target position when a write access is made to write data on the target position;

detecting means for detecting the position of the head in accordance with servo data read by the head;

memory means for previously storing target velocity data for controlling the read seek and target velocity data for controlling the write seek;

means for selectively reading target velocity data for controlling the read seek from the memory means when the read seek control is performed and for selectively reading target velocity data for controlling the write seek from the memory means when the write seek control is performed;

read seek control means for executing the read seek control by transmitting an amount of a control operation corresponding to the difference in the velocity between velocity indicated by target velocity data for controlling the read seek selected from the memory means and movement velocity obtained in accordance with the position of the head detected by the detecting means;

write seek control means for executing the write seek control by transmitting an amount of a control operation corresponding to the difference in the velocity between velocity indicated with target velocity data for controlling the write seek selected from the memory means and movement velocity obtained in accordance with the position of the head detected by the detecting means;

driving means for moving the head to the target position at the velocity determined in accordance with the amount of the control operation transmitted from the read seek control means or the write seek control means; and

memory means stores target velocity data for controlling the read seek and the write seek indicating velocity characteristics with which movement of the head is controlled, which have the same target velocity for use in an acceleration mode and a constant velocity mode and which have different target velocity for use in a deceleration mode in which the head approaches the target position.

7. In a disk drive having a head, a disk and a head positioning control system for positioning the head in a target position on the disk based on a servo data prerecorded on the disk, the head positioning control system comprising:

determining means for determining read seek control for moving the head to the target position when a read access is made to read data by the head from the target position on the disk or write seek control for moving the head to the target position when a write access is made to write data on the target position;

detecting means for detecting the position of the head in accordance with servo data read by the head;

memory means for previously storing target velocity data for controlling the read seek and target velocity data for controlling the write seek;

means for selectively reading target velocity data for controlling the read seek from the memory means when the read seek control is performed and for selectively reading target velocity data for controlling the write seek from the memory means when the write seek control is performed;

read seek control means for executing the read seek control by transmitting an amount of a control operation corresponding to the difference in the velocity between velocity indicated by target velocity data for controlling the read seek selected from the memory means and movement velocity obtained in accordance with the position of the head detected by the detecting means;

write seek control means for executing the write seek control by transmitting an amount of a control operation corresponding to the difference in the velocity between velocity indicated with target velocity data for controlling the write seek selected from the memory means and movement velocity obtained in accordance with the position of the head detected by the detecting means;

driving means for moving the head to the target position at the velocity determined in accordance with the amount of the control operation transmitted from the read seek control means or the write seek control means;

read control means includes means for executing read position control after the head has approached the target position by using target position locus data having a high velocity characteristic to position the head in an allowable range for the target position; and

the write seek control means includes means for executing write position control after the head has approached the target position by using target position locus data having a precise accuracy characteristic to position the head in a relatively narrow allowable range for the target position as compared with the allowable range for use when the read access is made.

8. In a disk drive having a head, a disk and a head positioning control system for positioning the head in a target position on the disk based on a servo data prerecorded on the disk, the head positioning control system comprising:

determining means for determining read seek control for moving the head to the target position when a read access is made to read data by the head from the target position on the disk or write seek control for moving the head to the target position when a write access is made to write data on the target position;

detecting means for detecting the position of the head in accordance with servo data read by the head;

memory means for previously storing target velocity data for controlling the read seek and target velocity data for controlling the write seek;

means for selectively reading target velocity data for controlling the read seek from the memory means when the read seek control is performed and for selectively reading target velocity data for controlling the write seek from the memory means when the write seek control is performed;

read seek control means for executing the read seek control by transmitting an amount of a control operation corresponding to the difference in the velocity between velocity indicated by target velocity data for controlling the read seek selected from the memory means and movement velocity obtained in accordance with the position of the head detected by the detecting means;

write seek control means for executing the write seek control by transmitting an amount of a control operation corresponding to the difference in the velocity between velocity indicated with target velocity data for controlling the write seek selected from the memory means and movement velocity obtained in accordance with the position of the head detected by the detecting means;

driving means for moving the head to the target position at the velocity determined in accordance with the amount of the control operation transmitted from the read seek control means or the write seek control means;

each of target velocity data items for respectively controlling the read seek and the write seek has a velocity characteristic composed of an acceleration mode, a constant speed mode and a deceleration mode; and

target velocity data for controlling the write seek is arranged in such a manner that start time of the deceleration mode is earlier than start time of the deceleration mode indicated by target velocity data for controlling the read seek.