JPS6318587A - Head positioning device for magnetic disk device - Google Patents

Abstract

PURPOSE:To shorten a time for positioning a head at a prescribed data track by constantly monitoring a temperature in a device and updating control data indicating the quantity of energization to a stored head actuator when the temperature changes by a value above a constant value. CONSTITUTION:A microcomputer 13 reads the detection signal of a temperature sensor 12, detects the temperature in the device, obtains the temperature when the data is previously stored in a chopping duty table and the present temperature, when the change in the temperature is within a preset tolerance, the quantity of off tracking of immediately positioned heads 6a, 6b is detected to control a servo and maintain the position of the head. When the microcomputer 13 detects that the present temperature changes above the preset tolerance, the heads 6a, 6b are sequentially positioned at the respective sampling tracks and the data corresponding to the duty ratio of an exciting voltage impressed to a step motor 7 is stored in the chopping duty table to update the data.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a head positioning device for a magnetic disk device. - [Prior art] When using a step motor as a head actuator for a magnetic disk drive, a microstep drive method is used in which the amount of rotation is arbitrarily set by adjusting the ratio of the amount of current to the two magnetic excitation phases of the step motor. is often adopted. In addition, in magnetic disk devices, the biggest cause of off-track occurrence, which is the positional deviation of the head from the target track, is thermal damage caused by the expansion and contraction of the mechanical parts of the carriage that mounts the magnetic disk and head due to temperature changes inside the device. Rack to off 1 is known.

For this reason, immediately after the power of the magnetic disk device is turned on, the head is sequentially positioned on sampling tracks, which are a plurality of preset data tracks, by predetermined servo control. Then, the ratio of the amount of current applied to the step motor when the step motor is positioned on each track is stored. Thereafter, when positioning the head on a predetermined data track according to instructions from the host computer, the step motor is controlled according to the stored current ratio, and initial positioning is performed according to the temperature during operation. Thereafter, accurate positioning is performed by predetermined servo control based on servo information recorded on the data track.

Incidentally, the temperature inside the magnetic disk device changes due to heat generation from the motor and electronic circuit components or fluctuations in the environmental temperature. Therefore, after such a temperature change occurs, when the head is positioned on a predetermined track for writing or reading data as described above, the step motor is driven according to the ratio of the energization amount memorized when the power is turned on. This results in a large off-track during initial positioning. Therefore,
If an off-track exceeding a certain amount occurs a certain number of times during such positioning, the head is sequentially positioned to each sampling track and the ratio of the energization amounts at that time is re-stored in the same manner as described above. After that, the head is positioned on a predetermined data track for writing or reading data.

For this reason, the conventional head positioning device for such a magnetic disk drive has a problem in that it takes time to position the head to a predetermined data track due to temperature fluctuations after startup.

[Objective] It is an object of the present invention to provide a head positioning device for a magnetic disk drive that can solve the above problems and shorten the time it takes to position the head on a predetermined data track.

[Configuration] For this reason, the present invention constantly monitors the temperature inside the device, and when the temperature changes by a certain value or more, the stored control data indicating the amount of current applied to the head actuator is updated according to the temperature at that time. It was designed to do so.

Hereinafter, one embodiment of the present invention will be described in detail.

FIG. 1 is a block diagram of a head positioning device for magnetic disk loading according to an embodiment of the present invention. This device is unitized and installed in a computer system (not shown), and power is supplied from the main body. In the figure, a magnetic disk 1 is fixed to a disk support 2 and driven by a spindle motor 3. The spindle motor drive circuit 4 rotates the spindle motor 3 at a constant speed. The carriage 5 is mounted with read/write heads (hereinafter simply referred to as heads) 6a and 6b that are in contact with each data recording surface of the magnetic disk 1, and is driven by a step motor 7. The step motor drive circuit 8 rotates the step motor 7 by a predetermined amount.

The information recording/reproducing circuit 9 sends a write signal to the heads 6a, 6b and also extracts the read signal, and the servo signal detection circuit 10 detects a servo signal from the extracted read signal. The interface circuit 11 is connected to a host computer (not shown) via a disk controller (not shown), and sends and receives control signals, status signals, read data, or write data to and from the disk controller. A temperature sensor 12 is installed inside this magnetic disk device to detect its internal temperature. The microcomputer 13 receives predetermined signals from each of the circuits described above and controls each of the circuits.

The head positioning device of this embodiment is configured as shown in FIG. 9 or above, and immediately after the power is turned on, the operation shown in FIG. 2 is executed. That is, first of all, the microcomputer 13 reads the detection signal of the temperature sensor 12, detects and stores the temperature inside the device at that time (process 21 in FIG. 2).
)6 By the way, the step motor drive circuit 8 of this embodiment drives the step motor 7 using the following microstep drive method. That is, Fig. 3 (a
), excitation voltages Vl and v2 are simultaneously applied to the two excitation phases A and 8 of the step motor 7. As shown in the same figure (b), the excitation voltages Vl and V2 are chopping pulses set so that the sum of on-times T1 and T2 becomes a constant period T, and the ratio of 1 hour TI to T2 That is, the duty ratio D=T s /T 2 is variable.

The rotation amount of the step motor 7 with respect to this duty ratio is shown as shown in FIG. It stops at the center of 8 phases.

When the duty ratio is set to D<1 or >1, the magnetic poles come to rest in the A-total or B-total position depending on the value of the duty ratio.

Now, the microcomputer 13 controls the step motor drive circuit 8 to rotate the step motor 7 by a predetermined amount.
One of the heads 6a or 6b selected in the initial state is caused to seek one of the sampling tracks, which are a plurality of data tracks specified in advance. At this time, the information recording/reproducing circuit 9 reads out the recording signal of the sampling track from the head 6a or 6b, and the servo signal detection circuit 10 detects the servo signal in the read signal, and determines the amount of off-track by predetermined processing. Outputs a signal indicating.

The microcomputer 13 controls the step motor drive circuit 8 while monitoring the signal, and adjusts the duty ratio 0 of the excitation voltages Vl and V2 to the step motor 7 so that the off-track amount is within a certain allowable range. do. Thereby, the heads 6a and 6b are correctly positioned on the sampling track. Microcomputer 13
stores the value of the duty ratio O of the excitation voltage V r rV 2 applied at this time.

The microcomputer 13 sequentially executes the above operation for all sampling tracks, and stores data corresponding to the duty ratio value stored in the above operation in the chopping duty table formed in the internal memory (process 22). , after this, microcomputer 1
3 reads the detection signal of the temperature sensor 12 and detects the temperature inside the device (process 23).Next, the change between the temperature when the data was stored in the chopping duty table last time and the current temperature detected above is detected. and determines whether the temperature change is within a preset allowable range (process 24). For example, after storing the data in the table in process 22, if the temperature change is small and within the allowable range ( Processing 24 v), microcomputer 13
Head 6a positioned just before 11.

The off-track amount of the head 6b is detected as described above and servo controlled to maintain the head position (process 25).

Here, if a control command is not received from a disk controller (not shown) (N in process 26), the above process 2
Return to step 3 and repeat the same operation at regular intervals.

Further, if any control command is received from the disk controller (Y in process 26), the command is identified. When the received control command is a seek command (Y in process 27), the microcomputer 13 drives the step motor 7 to cause the predetermined heads 6a and 6b to seek one predetermined data track.

At this time, the step motor 7 is driven with an excitation voltage corresponding to the duty ratio according to the data stored in the chopping duty table to position the heads 6a and 6b (process 28). Further, the off-track amount generated here is detected in the same manner as described above, and the head position is corrected according to predetermined servo control (process 29). Next, after the interface circuit 11 outputs a signal indicating the completion of reseek to the disk controller (not shown) (process 30), the process returns to the process 23 and repeats the above operation.During this process, the head position set above is set in process 25. is held, so the information recording/reproducing circuit 9 follows the control signal from the disk controller.

Information can be recorded on the magnetic disk 1 or information on the magnetic disk 1 can be reproduced.

On the other hand, the microcomputer 13 determines if the current temperature changes by more than a preset tolerance range from the temperature when the data was last stored in the chopping duty table (N in process 24), and The temperature at that time is memorized, the heads 6a and 6b are sequentially positioned on each sampling track in the same way as in process 22, and data corresponding to the duty ratio of the excitation voltage to be applied to the step motor 7 is stored. The data is stored in the chopping duty table and updated (processing 31).

Therefore, from then on, when a seek command is received (from Y in process 26 to Y in process 27) and positioning of the head is executed (process 28), based on the above data updated in accordance with the degree change. Since the step motor 7 is driven,
The amount of thermal off-track is reduced, and the above-mentioned accurate positioning is achieved.

Note that in process 27, when a control command other than a seek command such as a head selection command is received (N in process 27), a predetermined operation according to the command is executed (process 3).
2).

As described above, in this embodiment, the temperature inside the device is constantly detected, and the control data stored in the chopping duty table for head positioning is updated every time the temperature changes above a certain value. That's what I do. This reduces the amount of off-track that occurs when positioning the head for writing or reading data. Therefore, in the middle of such positioning as before.

Since the operation of updating the control data is not executed when a large off-track occurs more than a certain number of times, the head positioning time is shortened.

Now, FIG. 4 is a flowchart showing another embodiment of the head positioning device for a magnetic disk device according to the present invention. In this embodiment, a chopping duty basic table and a chopping duty common table are provided in the internal memory of the microcomputer 13.

4 differs from FIG. 2 in that processes 33 and 34 are provided in place of process 22, process 35 is provided in place of process 31, and furthermore, in process 28, the head is positioned according to the above-mentioned common table. This is the point.

In process 33, the same operation as process 22 in FIG. 2 is executed, and data indicating the duty ratio obtained by the operation is stored in the chopping duty basic table. Further, in step 34, the same data stored above is also stored in the common table.

As a result, when a head seek command is received from a disk controller (not shown) to position the heads 6a and 6b, the step motor 7 is driven based on the data stored in the common table in process 2a, so that ffi Accurate head positioning corresponding to the original oleo 2 o'clock position is performed.

On the other hand, if there is a temperature change of more than a certain value after the power is turned on, the microcomputer 13 determines this (N in process 24).

By the way, the off-track amount based on the temperature TE inside the device, which is called thermal off-track, is shown as shown in FIG. That is, 1. For example, in process 33, the temperature TE
(Suppose that the head is positioned on a specific data track under + and the off-track amount TR becomes zero, and at that time the step motor 7 is driven at a duty ratio D+. At this time, the above duty ratio 01 Data corresponding to is stored in the chopping duty basic table.

However, when the temperature inside the device rises to Ti=t, an off-track amount TRI will occur if the step motor 7 is driven at the same duty ratio D1 as described above.

Here, assuming that the off-track 1lTb+ is proportional to the temperature TE and setting the proportionality constant to 1, a linear equation is established.

TRt = +・(Tt t −TE O)
(1) On the other hand, off-track correction is performed by adjusting the amount of rotation of the step motor 7 that drives the heads 6a and 6b, and the amount of rotation is as shown in FIG. 3(c). It can be adjusted by adjusting the duty ratio of the excitation voltage.

Also, since the actual duty ratio setting j is within a certain range around D=1 as shown in section V in the figure, this section V
As shown in FIG. 6, it can be considered that the off-track correction amount is proportional to the duty ratio.

Now, at duty ratio D1, off-track -1t
Since T*+ has occurred, the duty ratio Do that should be set to correct this off-track amount TRI is expressed by the linear formula % formula %, where the proportionality constant at this time is 2. Here, the above formula (1) Substituting into equation (2) yields.

DO=D+ (TE I −TE o becomes 11 and 2, and the constant Ko becomes 0=KI・K2.

Do = DI(TE t −TE I) )・nio・
...(3).

That is, based on the value of the duty ratio DI set under the temperature TEI in process 33, the duty ratio Do to be set at the arbitrary temperature TEI can be calculated from the above equation.

Therefore, when the microcomputer 13 detects a temperature change exceeding the certain value (N in process 24), the microcomputer 13 uses each data indicating the duty ratio stored in the chopping duty basic table and the temperature at that time. Based on the above equation (3), a duty ratio to be newly set is calculated. Store the data corresponding to the calculated duty ratio in the chopping duty common table (
Processing 35).

As a result, in step 28, the head is positioned according to the above data, so that the position is always accurately determined according to the temperature at that time.

As described above, in this embodiment, a chopping basic table and a chopping duty common table are provided, and data corresponding to the duty ratio obtained by positioning the head to the sampling track is stored in the two tables. . and.

When a temperature change exceeding a certain value inside the device is detected.

A correction value for the above data is calculated according to the temperature at that time and is stored in the common table. Since the head positioning is performed according to the data in the above-mentioned common table, the amount of thermal off-track can be kept small, and the head positioning time can be shortened as in the previous embodiment. Furthermore, in this embodiment, since there is no need to position the head on the sampling track when the temperature change is detected, the duty ratio data can be quickly corrected.

In each of the above embodiments, the temperature is constantly monitored, but before receiving a head seek command from the disk controller and starting the head positioning operation, the temperature change is determined and the temperature change is determined to be large. Sometimes, the chopping duty table may be corrected.

[Effects] As described above, according to the present invention, when the temperature inside the device changes by a certain value or more, the data stored for controlling the bed actuator is updated.

As a result, the head positioning operation is interrupted,
The data updating operation described above is no longer executed, and the head positioning time is shortened.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a head positioning device for a magnetic disk device according to an embodiment of the present invention, FIG. 2 is a flowchart showing the operation of the device, and FIG. 3(a) is a microstep diagram of a step motor. Explanatory diagram of the drive system, same figure (b
) is a waveform diagram of the excitation voltage in that method, FIG. 4(c) is a graph diagram showing the magnetic pole position of the step motor with respect to the duty ratio of the excitation voltage, and FIG. A flowchart showing the operation of the head positioning device, FIG. 5 is an explanatory diagram of thermal off-track, and FIG. 6 is an explanatory diagram of off-track correction. 1... Magnetic disk, 2... Disk support. 3... Spindle motor, 4... Spindle motor drive circuit, 5... Carriage, 6a, 6b.
... Read/write head, 7... Step motor,
8... Step motor drive circuit, 9... Information recording/reproducing circuit, 10... Servo signal detection circuit, 11... Interface circuit, 12... Melon degree sensor, 13...
microcomputer. Agent Patent Attorney Crest 1) Makoto 1 噌□□□; 1-Daibishinro, \Lroe F91!14 Appetizer Figure 3 (a) (b) (C) (0) (1) (■) □Dute/jLT+T2(D) Fig. 5 □A degree Tε Fig. 6-1 Duty North D

Claims (2)

[Claims] (1) A step motor that moves the head onto each track, and a step motor that rotates a predetermined amount,
microstep driving means for adjusting the rotation amount by changing the ratio of the amount of current supplied to the two excitation phases of the step motor; and a storage means for storing data corresponding to the ratio of the amount of current supplied to the step motor. A head positioning device for a magnetic disk drive that controls the step motor based on the stored data includes a temperature sensor that detects the temperature inside the device, and a temperature change detector that detects when the temperature has changed by more than a certain value. means for controlling the microstep drive means to position the head at a plurality of preset sampling tracks immediately after power is turned on and when the temperature change is detected; A head positioning device for a magnetic disk drive, comprising: memory update means for storing data corresponding to the ratio of the energization amounts in the memory means, and reducing an amount of off-track during positioning of the head. (2) A step motor that moves the head onto each track, and a step motor that rotates a predetermined amount,
microstep drive means for adjusting the amount of rotation by changing the ratio of energization amounts for the two excitation phases of the step motor; and a first memory for storing data corresponding to the ratio of the energization amounts supplied to the step motor. A head positioning device for a magnetic disk drive that controls the step motor based on the stored data, the head positioning device comprising: a temperature sensor that detects the temperature inside the device; control means for positioning the head on a plurality of preset sampling tracks, and storing data corresponding to the ratio of the amount of energization supplied to the step motor at that time in the first storage means; a second storage means for storing the corrected data; a temperature change detection means for detecting that the detected temperature has changed by more than a certain value; and memory updating means for correcting the data stored in the first storage means when a change is detected according to the temperature conditions at that time, and storing the corrected data in the second storage means, A head positioning device for a magnetic disk device, characterized in that the amount of off-track during head positioning is reduced.