JPH03209675A - Magnetic head driving control device - Google Patents

Abstract

PURPOSE:To shorten a seeking time by increasing the maximum value of an objective speed signal when the objective moving distance of a magnetic head is longer than a reference distance. CONSTITUTION:A position signal former 33 outputs the position signal of the magnetic head 31 based upon a signal read out from the head 31 and a speed detector 34 detects the real moving speed of the head 31. When a cylinder cross detector 35 detects the crossing of the cylinder of the head 31 from the output of the former 33, the objective speed signal is formed by a data processing part 37 and a D/A converter 38 in a CPU and a head moving speed is controlled in accordance with a speed error signal obtained from a subtractor 42. On the other hand, the processing part 37 compares the reference distance with the objective distance, controls the switching of contacts S2, S3 of a switch 41, and when the target distance is larger than the reference distance, the maximum value of the objective speed is increased and the seaking time can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a magnetic head drive control device used in a magnetic disk drive.

(Prior Art) Generally, a magnetic disk device is a device that uses a magnetic head to magnetically record and reproduce data on a magnetic disk (hereinafter abbreviated as a disk), which is a magnetic recording medium. Multiple disks are attached to one spindle,
A magnetic head is provided corresponding to each disk. A plurality of cylinders (tracks) are defined on the disk, and a magnetic head is positioned for each cylinder to record and reproduce data in the rotational direction of the disk.

In such a magnetic disk device, positioning of the magnetic head to a target cylinder is performed based on position information written on the disk in advance.

FIG. 4 shows the configuration of such a magnetic head drive control device that positions the magnetic head to the target cylinder. Position information is written in advance on a disk (not shown), and this position information is read by a magnetic head 11 and output to a position signal generator 13 via an amplifier 12. The position signal generator 13 detects the position of the magnetic head 11 based on this position information, and outputs the resulting position signal to the speed detector 14 and cylinder cross detector 15.

The speed detector 14 detects the magnetic head it based on the position signal.
detects the actual moving speed of the motor and outputs an actual moving speed signal v1 via the resistor 16. In addition, the cylinder cross detector 15
detects the number of cylinders crossed by the magnetic head 11.

Then, the data processing unit (CPU) 17 calculates a moving target speed according to the number of remaining moving cylinders based on the detection result of the cylinder cross detector 15. The data processing unit 17 outputs data corresponding to the calculated movement target speed to the D/A converter 18.

The D/A converter 18 converts the data from the data processing section 17 into an analog signal, and outputs the moving target speed signal v2 via the resistor 19.

In this way, the actual moving speed signal V1 of the magnetic head 11 is
When the moving target speed signal V2 is obtained, the subtracter 20 generates an error speed signal V3 corresponding to the difference between the two speeds, and this signal is applied to the power amplifier 22 through the error amplifier 21. Therefore, the voice coil 23 that drives the magnetic head 11 is supplied with a current determined by the error velocity signal v3, thereby driving the magnetic head 11 toward the target cylinder.

Incidentally, acceleration and deceleration during movement (seek) of the magnetic head are generally performed by constant current acceleration and constant current deceleration, and the deceleration current is often 2/3 of the acceleration current. In this case, it has been theoretically calculated that the average seek time can be shortened the most by driving with the maximum current lll1ax for a distance of 1/3 of the moving distance of the magnetic head, and such control is performed. .

FIG. 5 is a diagram for explaining this ideal drive current, where the horizontal axis is the moving time of the magnetic head and the vertical axis is the drive current. In the figure, if T1 is the time for the magnetic head to move to the target cylinder position and Il0aX is the maximum current, acceleration current drive is performed with the maximum current 1a+ax until T1/3 time, and then deceleration current drive is performed with ImaX2/3. By doing so, the average seek time can be shortened the most.

However, the maximum value of the moving target speed that can be set is D
/A converter 17 determines the value.

Therefore, the target speed signal V1 outputted via the resistor 19 sets the constant speed mode in which the magnetic herad 11 is moved at the maximum speed Vmax. Therefore, in the conventional device, it is impossible to achieve a speed higher than the maximum speed v max obtained by the maximum moving target speed. In addition, when decelerating the magnetic head 11, it is necessary to control the deceleration current within a range that does not exceed a specified value, so the movement target speed Vll1aX, which limits the actual movement speed of the magnetic head 11, is set to a certain constant value. Is it necessary? Because of this, the maximum speed v max of the magnetic head 11
The value was limited.

From the above, conventionally, when the magnetic head 11 seeks, the target movement distance is 1/3 of the maximum movement distance.
If it was longer, a constant speed period in which no acceleration or deceleration was performed was created in order to reach the maximum speed v max. FIG. 6 shows the relationship between the moving time and moving speed of the magnetic head 11 in conventional control.

That is, in FIG. 6, the horizontal axis is the travel time, the vertical axis is the travel speed, and the travel time for the maximum travel distance is Tωa.
Xs If the time required to move a distance of 1/3 of the maximum movement distance is T2, the movement speed of the magnetic helad 11 is rcl-a when the target movement distance is shorter than 1/3 of the maximum movement distance. -dj, and when the target movement distance is 1/3 of the maximum movement distance, the path rO-b-eJ is followed.

On the other hand, if the target moving distance is longer than 1/3 of the maximum moving distance, the value of v max is constant as described above, so the moving speed of the magnetic head 11 follows the trajectory of ro-b-c-fJ. Follow. In this case, the period between rb and cJ is a constant speed period.

(Problems to be Solved by the Invention) As described above, in the case of the conventional magnetic head drive control device, the maximum speed of the magnetic head is limited. For this reason,
When the target moving distance is longer than a predetermined reference moving distance, a constant speed period occurs, and the seek time cannot be shortened.

The present invention has been made in view of the above points, and provides a magnetic head drive control device that can drive and control a magnetic head without providing a constant speed period even when the target movement distance is longer than a predetermined reference movement distance. The purpose is to provide

[Structure of the Invention] (Means for Solving the Problems) The present invention generates an error speed signal according to the difference between a moving target speed signal for a magnetic head and an actual moving speed signal of the magnetic head, and In a magnetic head drive control device that drives and controls a magnetic head based on the following, a target moving distance detecting means detecting the distance traveled by the magnetic head, and a moving target corresponding to the target moving distance detected by the target moving distance detecting means. data generating means for generating target speed data for setting a speed signal, the data generating means generating target speed data when the target moving distance detected by the target moving distance detecting means is longer than a predetermined reference moving distance. The maximum speed value of the moving target speed signal converted from the target speed data is increased to a predetermined value, and the magnetic head is driven and controlled by a control mode consisting of an acceleration control mode and a deceleration control mode based on this moving target speed signal. It consists of

(Function) In the magnetic head drive control device configured in this manner, even during the constant speed period that conventionally occurred when the target movement distance of the magnetic head was longer than the predetermined reference movement distance,
By controlling the acceleration/deceleration of the magnetic head, the seek time is reduced.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a magnetic head drive control device according to the same embodiment. In FIG. 1, a magnetic head 31 is positioned on a cylinder (track) of a disk (not shown), and reads position information written on the disk for positioning the magnetic head. The position information read by the magnetic head 11 is output to the position signal generator 33 through the amplifier 32.

The position signal generator 33 detects the position of the magnetic head 31 based on the position information read by the magnetic head 31, and transmits the position signal obtained as a result of this detection to the speed detector 34.
, and output to the cylinder cross detector 35. The speed detector 34 detects the actual moving speed of the magnetic head 31 based on the position signal from the position signal generator 33, and outputs the actual moving speed signal s1 via the resistor 36. The cylinder cross detector 35 detects that the magnetic head 31 has crossed the cylinder based on the position signal from the position signal generator 33, and outputs the cylinder cross signal obtained as a result to the data processing unit (CPU) 37. do. The data processing unit 37 detects the target movement distance (the number of cylinders to the target cylinder) of the magnetic head 31 based on the cylinder cross signal from the cylinder cross detector 35. The data processing unit 37 outputs to the D/A converter 38 data that is the basis of a moving target speed signal corresponding to the detected moving target distance. The D/A converter 38 performs D/A conversion on the data from the data processing section 37, and converts the data from the data processing section 37 into a moving target speed signal S2. Output S3. The maximum speed of the moving target speed signal S2 outputted via the resistor 39 is set to v wax.

Further, the maximum speed of the moving target speed signal S4 outputted via the resistor 40 is set to be equal to or higher than v a + ax. This movement target speed signal S3 is, for example, the magnetic head 31
The speed corresponding to the maximum movement distance is set. The data processing unit 37 sets the maximum movement distance of the magnetic head 31, 173, as a predetermined reference movement distance, and when the detected target movement distance is smaller than the predetermined reference movement distance, the data processing unit 37 generates a movement target speed signal S.
A speed switching signal S4 for selecting speed switching signal S4 is output. On the other hand, if the detected target moving distance is larger than the predetermined reference moving distance, a speed switching signal S4 is output that selects the moving target signal S3 set to the maximum speed VIIlax of the magnetic head 31 or higher. Furthermore, when the magnetic head 31 is driven to a speed equal to or higher than v max by the movement target speed signal S3, and is decelerated from there and reaches v max, the data processing unit 37 switches the switch 41 to output the target speed signal S2. Output. The subtracter 42 receives the moving target speed signal S2. S3 and the actual moving speed signal S1 are calculated, and an error speed signal S5 is obtained.
It is output to the error amplifier 43 as a signal. Power amplifier 44 supplies a current corresponding to the output of error amplifier 43 to voice coil 45 . The voice coil 45 controls the drive of the magnetic head 31 according to the supplied current value.

Next, the operation of this embodiment will be explained.

When the magnetic head 31 moves on the disk during seek,
The position information written on the disk is read by the magnetic head 31, and based on this position information, the position signal generator 3
3, the position of the magnetic head 31 is detected. When the position of the magnetic head 31 is detected, a position detection signal is output from the position signal generator 33 to the speed detector 34 and the cylinder cross detector 35.

The speed detector 34 detects the actual moving speed of the magnetic head 31 based on the position detection signal, and outputs an actual moving speed signal S1.

On the other hand, the cylinder cross detector 35 detects the number of cylinder crosses of the magnetic head 31 based on the position detection signal, and outputs the resulting cylinder cross detection signal to the data processing section 36. The pig processing unit 36 detects a target moving distance of the magnetic head 31 based on this cylinder cross detection signal, and outputs data for driving the magnetic head at a target speed corresponding to the detected target moving distance.

Here, if the target movement distance detected by the data processing unit 37 is shorter than the predetermined reference movement distance (1/3 of the maximum movement distance), the data processing unit 37 converts the data corresponding to the target movement distance into D/ At the same time, it outputs a speed switching signal S4, switches the switch 41 to the resistor 39 side, and outputs a movement target speed signal S2. The subtracter 42 generates an error speed signal S5 indicating the difference between the moving target speed signal S2 and the moving actual speed signal S1 output from the speed detector 34.
is output to the error amplifier 43. Power amplifier 44 supplies current based on error speed signal S5 to voice coil 45. The voice coil 45 drives and controls the magnetic head 31 according to the supplied current value.

Next, if the target moving distance detected by the data processing section 37 is longer than the predetermined reference moving distance (1/3 of the maximum moving distance), the data processing section 37 outputs a speed switching signal S4 and turns on the switch 41. Switch to the resistor 40 side. As a result, a moving target speed signal S3 whose maximum speed is set to be equal to or higher than V wax is output. In this way, an error speed signal S5 indicating the difference between the moving target speed signal S3 and the moving actual speed signal S1 is output to the error amplifier 43. Thereafter, the magnetic head 31 is driven and controlled in the same manner as in the case of the target speed signal S2.

Here, with reference to FIGS. 2 and 3, the operation when the target movement distance is longer than the predetermined reference movement distance (I & ⅓ of the large movement distance) will be specifically explained.

FIG. 2 is a diagram showing the relationship between the moving speed and travel time of the magnetic head 31 and the switching timing of the switch 41, and FIG. 3 is a diagram showing the relationship between the travel time and drive current of the magnetic head 31. In the figure, the solid line is the characteristic obtained by the control of this embodiment, the broken line is the characteristic obtained by the conventional control, and T3 is the target movement end time when the target movement distance is greater than 1/3 of the maximum movement distance. As described above, it has been theoretically calculated that the average seek time can be shortened the most by driving with the maximum current IIIax for a distance that is 1/3 of the maximum moving distance of the magnetic head 31. In this case, speed control is performed so that V as shown in FIG.
Time T required to stop smoothly from IIlax
a is always constant. Further, the time for supplying the maximum current I rnax is the time Tb until the robot moves ⅓ of the target moving distance.

Therefore, the detected target movement distance is 1 of the maximum movement distance.
/3, the data processing unit 37
The switch 41 is changed over so that the moving target speed signal S3 is outputted via the moving target speed signal S3. The data processing unit 37 increases the maximum value of the moving target speed by outputting the target speed data through the resistor 40, and sets it to Vl that is greater than or equal to v wax. As a result, during the time Tb, the voice coil 45
A current Iwax is supplied to the current Iwax. When the magnetic head 31 is accelerated and reaches a speed v1 corresponding to the target moving distance,
Deceleration control is performed. When the speed of the magnetic head 31 is reduced to v 2 +nax by this deceleration control, the data processing device 37 switches the switch 41 and outputs the moving target speed signal S2. While performing the conventional deceleration according to the moving target speed signal S2, the magnetic head 31
Move to the target cylinder. When the magnetic head 31 approaches the target cylinder, control is shifted to position control for positioning the magnetic head 31 on the track.

In this way, even if the detected movement target distance is longer than the predetermined reference movement distance, in order to perform drive control by acceleration control and deceleration control without providing a constant speed period, the seek time Tc shown in FIG. It can shorten the time. Further, in this case, since the deceleration control after the speed of the magnetic disk 31 during the deceleration period becomes equal to or less than v wax is performed based on the moving target speed signal S2 as in the conventional case,
Smooth positioning is performed.

[Effects of the Invention] As described above, according to the present invention, when the target movement distance of the magnetic head is longer than a predetermined reference movement distance, the maximum value of the movement target speed signal according to the target movement distance is increased to a predetermined value. By doing so, drive control is performed using a control mode consisting of an acceleration control mode and a deceleration control mode during the constant speed period that occurs in the case of conventional magnetic head drive control, so the seek time for the magnetic head to reach the target cylinder is shortened. It becomes possible to do so.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the circuit configuration of a magnetic head drive control device according to an embodiment of the present invention, and FIG. 2 shows the relationship between the moving speed and moving time of the magnetic head and the switch switching timing in the same embodiment. FIG. 3 is a diagram showing the relationship between the travel time of the magnetic head and the drive current in the same embodiment, FIG. 4 is a block diagram showing the circuit configuration of a conventional magnetic head drive control device, and FIG. FIG. 6, which is a diagram for explaining the ideal drive current, is a diagram showing the relationship between the moving time and moving speed of the magnetic head in a conventional magnetic head drive control device. 31...Magnetic head, 32...Amplifier, 33...
Position signal generator, 34... Speed detector, 35... Cylinder cross detector, 36.39.40... Resistor,
37... Data processing section, 38... D/A converter, 4
DESCRIPTION OF SYMBOLS 1...Switch, 42...Subtractor, 43...Error amplifier, 44...Power amplifier, 45...Voice coil, Sl...Movement actual speed signal, S2, S3...Movement Target speed signal, S4...Speed switching signal, S5...
Error speed signal.

Claims (1)

[Claims] A magnetic device that generates an error speed signal according to the difference between a movement target speed signal for the magnetic head and an actual movement speed signal of the magnetic head, and drives and controls the magnetic head based on this error speed signal. In the head drive control device, a target moving distance detecting means for detecting the distance traveled by the magnetic head, and a target speed for setting a moving target speed signal according to the target moving distance detected by the target moving distance detecting means. a data generating means for generating data; and a moving target converted from the target speed data generated by the data generating means when the target moving distance detected by the target moving distance detecting means is longer than a predetermined reference moving distance. Increase the maximum speed value of the speed signal to a predetermined value,
A magnetic head drive control device comprising: drive control means for controlling the drive of the magnetic head in a control mode consisting of an acceleration control mode and a deceleration control mode based on the moving target speed signal.