JP2812073B2 - Track-to-track access method for disk units - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a disk drive,
The present invention relates to a method for causing a head to access between tracks at high speed.

[0002]

2. Description of the Related Art A control system of a disk drive generates a reference speed to be followed by a head in accordance with a difference between a head position and a target position, and a speed mode in which the head speed follows the reference speed; There are two control modes: a position following mode for following the track center.

In a speed mode control system, a target speed for accelerating / decelerating the head and moving at a constant speed is generated in accordance with the difference between the head position and the target position, and is proportional to the difference between the target speed and the head speed. The generated actuator drive signal is generated.

In the position tracking mode, a signal proportional to the difference between the target position and the head position is subtracted from a signal proportional to the head speed, so that the head converges and tracks the target position. .

The inter-track access operation is realized by first moving the head to the vicinity of the center of the adjacent target track in the speed mode, and switching from the speed mode to the position following mode near the center of the target track.

[0006]

In the inter-track access operation of the above-described disk device, the time in the speed mode is short, and the mode is switched to the position following mode in a state in which the reference speed cannot be followed. If the speed deviation is large, the transient response after switching to the position following mode is poor, which causes the seek time to be prolonged.

[0007]

In the disk drive of the present invention, the target speed and the head speed are set between the center of the track followed by the head before the inter-track access operation and the target position of the inter-track access operation. The speed deviation between the sample points is set, independent accumulation memories are assigned to the sample points, and when the head reaches the sample point, the signal stored in the accumulation memory assigned to the reached sample point Is added to the drive current of the actuator, and at the same time, the speed deviation is accumulated in the accumulation memory allocated to the reached sample point, thereby performing an access operation between tracks.

[0008]

According to the inter-track access method of the disk device of the present invention, the speed deviation between the target speed and the head speed is compressed by repeatedly performing the inter-track access operation. Variations in the initial value are reduced, and a more stable high-speed inter-track access operation can be realized.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a speed mode controller showing one embodiment of the present invention, and FIG. 2 is a block diagram of the entire control system of a disk drive.

According to the servo information 9 read from the disk surface 1, position error information of the head 2 can be obtained from the track center. The position error signal generator 3 generates a position error signal 10 as a periodic signal for each track from the servo information 9 and inputs the position error signal 10 to the controller 5. The signal 13 output from the controller 5 is converted into a drive current 14 by the power amplifier 6 and output to the actuator 7. This drive current value is converted to a current sense signal 12 by the current detector 8 and input to the controller 5. The number of tracks passed by the head is counted by the passing track counter 4 from the position error signal 10, and the number 11 of tracks passed by the head is sent to the controller 5. In the controller shown in FIG. 1, head position information 20 is obtained from the position error signal 10 and the number of tracks 11 passed by the head. From the head position information 20 and the current sense signal 12, the speed estimator 16 calculates the head speed 22.
Is required.

The target speed generator 15 obtains the remaining access distance of the head from the position information 20 of the head and the target position, and generates a target speed 21. Target speed 21
As an example, when the remaining distance of the access operation is large, the maximum speed of the head obtained from the performance of the actuator is provided, and a target speed proportional to the square root of the remaining distance is provided so that the deceleration of the access operation is constant. . This switching is performed after the target maximum speed and the deceleration target speed become equal.

The target speed 21 generated by the target speed generator 15 and the estimated speed 2 of the head obtained by the speed estimator 16
2 and the actuator drive signal 2
6 is generated.

Here, a correction value 25 for increasing the gain is added so as to further reduce the speed deviation. A method of generating the correction value 25 will be described with reference to FIG.

First, in the inter-track access operation, since the access distance is equal to the track pitch, the track pitch is equally divided, and the integration memory 19 is set corresponding to each moving distance.

When the head moves to a set distance,
The correction value 25 is switched to a value in the integration memory corresponding to the moving distance of the head. At the same time, the value is accumulated in the value of the accumulation memory corresponding to the moving distance of the speed head at that time, and the value is replaced with the value of the accumulation memory.

Further, in order to suppress the high frequency fluctuation of the correction value 25, the integrated value is taken into the integration memory after the high frequency component is reduced by using the filter 18. Thereby, the speed deviation 2 between the target speed 21 and the head speed 22 is obtained.
3, the speed deviation at the time of switching from the speed mode to the position mode is compressed by repeating the inter-track access operation,
The variation in the inrush speed when switching from the speed mode to the position following mode is eliminated, and the adverse effect of the transient response such as overshoot is greatly reduced, so that the inter-track access time is reduced.

In the disk drive, the influence of an external force applied to the actuator is different between the outer seek operation from the inner circumference to the outer circumference and the inner seek operation from the outer circumference to the inner circumference due to the influence of the FPC and the like attached to the actuator. The value of the speed deviation between the speed and the head speed often differs. As a countermeasure, it is a very effective method to divide the integration memory between the outer seek operation and the inner seek operation.

Further, when the actuator is of a rotary type, a phenomenon in which the force constant decreases when the head is located at the inner and outer peripheral portions of the disk may appear. In this case, the speed deviation between the target speed and the head speed at the inner, outer, and center portions of the disk fluctuates so as not to be ignored. As a countermeasure, it is an effective method to provide another accumulation memory depending on the location of the inter-track access depending on the inner circumference, outer circumference, and center of the disk.

[0019]

As described above, according to the present invention, since the inter-track access operation is repeatedly performed, the speed deviation between the target speed and the head speed is compressed, so that when the mode is switched from the speed mode to the position following mode. Variations in the initial value are reduced, and a more stable high-speed inter-track access operation can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of the present invention.

FIG. 2 is a block diagram of a speed mode controller of the embodiment.

FIG. 3 is a setting diagram of an integration memory according to the present invention.

[Explanation of symbols]

 21 Target speed 22 Head speed 23 Speed deviation 25 Speed deviation correction value

Claims (3)

(57) [Claims] A power amplifier for supplying a drive current to an actuator for moving the head; a speed detector for obtaining the speed of the head by estimation or measurement; and a target speed generator for generating a target speed of the head. The head is moved to near the center of the target track by a speed mode that causes the head speed to follow the target speed, and from the speed mode near the center of the target track,
In a control method for performing an inter-track access operation of moving the head to an adjacent track by switching the head to a position following mode in which the head follows the center of the target track, the head follows the inter-track access operation. A sample point for sampling a speed deviation between the target speed and the head speed is set between the center of the track and the target position in the inter-track access operation, and is independent of the sample point. At the time when the head reaches the sample point, an output proportional to the signal stored in the integration memory assigned to the reached sample point is added to the drive current of the actuator. Integrating the speed deviation into the integration memory assigned to the sample point An inter-track access method for a disk device. 2. The method according to claim 1, wherein the speed deviation is integrated by different integration memories between an inner seek operation in which the head moves from the outer periphery to the inner periphery and an outer seek operation in which the head moves from the inner periphery to the outer periphery. 2. The inter-track access control method for a disk device according to claim 1, wherein: 3. The storage surface of the disk is divided into zones in the radial direction, and different accumulation memories are assigned to the respective zones. When performing inter-track access, the accumulation memory of the zone to which the head position or the target position before the access belongs is used. 2. The inter-track access control method for a disk device according to claim 1, wherein the speed deviation is integrated by performing the integration.