JPS60106082A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To make the adjustment of a head shifting speed unnecessary at the time of shipment at a factory by detecting the maximum speed at the time of shifting of a head by a counter, and calculating the maximum shifting speed to be a target figure according to the output of the counter, and supplying the result to a servo control circuit. CONSTITUTION:A counter 106 counts a cylinder passing signal 208, latches the counted value by a positioning action termination signal 205, and outputs the result to a counter reading bus 209. These data correspond to the maximum speed of header shifting. A data conversion circuit 7 inputs data on the counter reading bus 209, and by using the result, a speed adjusting signal 210 having the value to match the head shifting speed to a target speed is calculated, which is transmitted to a servo control circuit 103. Thus deviation of a head shifting speed from a target figure due to the individual difference of each part of a head drive part and due to aging can be prevented, and a shifting speed can be matched automatically to a target figure by the shift of head several times.

Description

TECHNICAL FIELD The present invention relates to a magnetic disk device that controls the positioning of a read/write head on a magnetic disk using a closed loop control method.

Prior Art In a conventional device of this type, a servo control circuit supplies a head drive signal to a magnetic head drive unit according to the direction of movement of the head and the number of moving cylinders, and the magnetic head drive unit performs readout using a current according to the input signal. The magnetic head is controlled by closed-loop control in which the write head is driven, the head positioning information read from the read/write head is fed back into the servo control circuit, and the servo control circuit modifies the head drive signal with the positioning information read signal. It is moved to the target cylinder and held on the target cylinder.

The above-mentioned conventional magnetic disk drive has a disadvantage in that it requires manual adjustment at the time of shipment from the factory because differences in head movement speed occur due to variations in circuit elements in the servo analog circuit, variations in mechanical parts, and the like. Another drawback is that the head movement speed adjusted at the time of shipment cannot be maintained due to aging of the circuit elements and mechanical parts.

[1] The CI feature of the present invention is to solve the above-mentioned conventional drawbacks, and to easily and automatically adjust the head movement speed by moving the head several times when turning on the power of the device, etc. The object of the present invention is to provide a magnetic disk device that can be shipped without adjusting the head movement speed.

Structure of the Invention The magnetic disk device of the present invention includes a magnetic disk plate mounted thereon, a read/write head for writing and reading information on the magnetic disk plate, and a head drive signal supplied from a servo control circuit described later. a magnetic head drive unit that drives the head; a positioning information reading circuit that outputs head positioning information read by the magnetic head and written on the disk plate to a servo control circuit described later; and a moving direction of the head and a moving cylinder. A positioning control logic circuit that outputs a number, etc., and a head drive signal that is supplied to the magnetic head drive unit by the output of the positioning control logic circuit, and a device determination information readout signal that supplies the head drive signal to the magnetic head drive unit according to the output of the positioning control logic circuit, and a device determination information readout signal that outputs the head drive signal. In a servo surface servo-type magnetic desk device equipped with a servo control circuit that performs closed-loop control of the head position and head movement speed by correcting the positioning control logic circuit, the head movement start signal output from the positioning control logic circuit is input. a timing setting circuit that outputs a window signal of a certain time width after a certain period of time from the start signal; a counter that counts the cylinder passing signal supplied from the servo control circuit during the period of the window signal output from the timing setting circuit; a data conversion circuit that compares the output of the counter with a preset maximum speed value and outputs a speed adjustment signal to the servo control circuit; and a data conversion circuit that detects that the output of the counter is within a certain range and outputs an adjustment operation end signal. and a data comparison circuit that outputs.

Embodiments of the Invention Next, the present invention will be described in detail with reference to one drawing.IJJ
do.

FIG. 1 is a block diagram showing one embodiment of the present invention,
Only the portions related to head positioning of the magnetic disk device are shown. That is, servo control circuit 1
03 outputs a head drive signal 201 based on the head movement direction signal 203 and head movement cylinder number signal 204 supplied from the positioning control logic circuit 104 and supplies it to the magnetic head drive section 101, and receives feedback input from the positioning information reading circuit 102. The read/write head 303 is controlled by closed-loop control in which the head drive signal 201 is modified by the positioning information readout signal 202.
．． 304 is moved to and held on the target cylinder.

The magnetic head drive unit lot is controlled by a head drive signal 201 supplied from the servo control circuit 103, and physically drives the read/write heads 303 and 304 by outputting a current according to the signal. The read/write heads 303 and 304 are connected to the magnetic disk 301.
．． The positioning information read from the positioning information readout circuit 302 is amplified and decoded by the positioning information readout circuit 102, and is fed back to the servo control circuit 103 as a digital positioning information readout signal 202.

The positioning control logic circuit 104 outputs a head movement direction signal 203 and a head movement cylinder number signal 204 to the servo control circuit 103 to start the head movement operation, and also sends a head movement start signal 206 to the timing setting circuit 105. In addition, the positioning operation end signal 205 from the servo control circuit 103 is inputted, and the head is moved again as described later.

The timing setting circuit 105 generates a timing window signal 20 of a certain time width one foot after the head movement start signal 206 is manually inputted from the positioning control logic circuit 104.
7 is output and supplied to the counter 106.

The timing window signal 207 is a second signal, and its start time a and end time a' are set within a period bb' during which the moving speed of the head is constant. The actual moving speed of the head causes a deviation from the standard value, so there is variation between b and b', but even when the deviation is maximum, a and a' are within the period bb'. It is necessary to set E2 so that

Returning to the first factor, the counter 106 receives the cylinder passage signal 208 during the period of the second timing window signal 207.
is counted, and the count value is latched by the positioning operation end signal 205 and output to the counter readout path 209. A cylinder passing signal 208 is transmitted to the servo control circuit 1 when the magnetic head passes through the cylinder.
03, the output data of the counter 106 corresponds to the moving speed of the head during the period of the timing window signal 207. Data conversion circuit 10
7 inputs data on the counter read bus 209;
This is compared with the target moving speed, and a speed adjustment signal 210 is generated.
is output and supplied to the servo control circuit 103.

The servo control circuit 103 receives the speed adjustment signal 2
10, the head drive signal 201 is changed so that the next head movement speed becomes the target i1. When the data on the counter readout path 209-L falls within the allowable range for the target head movement speed, the data comparison circuit 108 outputs an adjustment operation end signal 211 to the positioning control logic circuit 108.
Supply on 04. The positioning control logic circuit 104 ends the adjustment operation when the adjustment operation end signal 211 is input.

The positioning control logic circuit 104 receives the adjustment operation end signal 21
If 1 is not input, the head movement direction signal 20 is input again.
3 and the head movement cylinder number signal 204 are output to the servo control circuit 103 to start the head movement operation for the maximum distance, until the adjustment operation end signal 211 is obtained.
Adjustment operations similar to those described above are repeated.

Next, the operation of this embodiment will be explained. First, the 1-positioning control logic circuit 104 outputs a head movement direction signal 203 and a head movement cylinder number signal 204 to the servo control circuit 103 to start a maximum distance head movement operation.

When the servo control circuit 103 is supplied with the head movement direction signal 203 and the movement cylinder number signal 204, it controls the movement speed of the head and controls the head movement speed by feedback inputting the positioning information readout signal 202 and outputting the head drive signal O1. Performs positioning control.

On the other hand, in response to the head movement start signal 206 supplied from the positioning control logic circuit 104 at the time of starting the head movement operation, the timing setting circuit 105 outputs a timing window signal 207 and supplies it to the counter 106. It counts the cylinder passing signal 208 and latches the count value in response to the 1 positioning operation end signal 205 and outputs it onto the counter readout bus 209. This data corresponds to the maximum head movement speed.

The data conversion circuit 107 inputs the data on the counter readout bus 209 and uses the data to calculate a speed adjustment signal 210 having a value that makes the head movement speed match the target speed, and sends it to the servo control circuit 103.

On the other hand, the data comparison circuit 108
09 is compared with a preset target value, and if the difference is within a certain tolerance range, an adjustment operation end signal 211 is output and the positioning control logic circuit 104
The 0 positioning control logic circuit 104 outputs the adjustment operation end signal 211 after inputting the positioning operation end signal 205.
When is input, the adjustment operation ends. When the adjustment operation end signal 211 is not input, the maximum distance head movement command is given to the servo control circuit 103 again in the same way as described above, and the same process is performed until the data comparison circuit 108 outputs the adjustment operation end signal 211. Repeat the action.

Therefore, in this embodiment, the head movement speed is prevented from deviating from the target value due to individual differences in each part of the head drive part, aging, etc., and the movement speed is automatically adjusted to the target value by moving the head several times. It is possible to match. Further, there is no need to adjust the head movement speed at the time of shipment from the factory.

Positioning control logic circuit 104° timing setting circuit 105 of the above-described embodiment. The data conversion circuit 107 and the data comparison circuit 108 are constituted by a microprocessor and a read-only memory connected to the microprocessor, and the positioning control logic circuit 104. Timing setting circuit 1
05° data conversion circuit 107. It is also possible to realize the same functions as in the above embodiment by incorporating the functions of the data comparison circuit 108 and the like into firmware.

Effects of the Invention As described above, in the present invention, the maximum speed during head movement is detected by a counter, and the servo control circuit calculates a speed adjustment signal such that the maximum movement speed becomes a target value based on the output of the counter. Since the servo control circuit is configured to supply the above-mentioned speed adjustment signal, it is possible to automatically adjust and control the moving speed of the head to match the target value by inputting the speed adjustment signal. Therefore, it is possible to prevent the head movement speed from deviating from the target value due to variations in component parts or changes over time, and there is no need to adjust the head movement speed at the time of shipment from the factory.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG. 2 is a time chart showing the relationship between the timing window signal and the head movement speed in the above embodiment. In the figure, 101: a1 head drive unit, 102: positioning information reading circuit, 103: servo control circuit, 104: positioning control logic circuit, 105: timing setting circuit, 106: counter, 107: data conversion circuit, 108: Data comparison circuit, 201: Head drive signal, 2o2: Positioning information read signal, 2o3: Head movement direction signal, 204: Head movement cylinder number signal, 2
05: Positioning operation end signal, 2o6: Head movement start up, 207: Timing window signal, 208 Niji cylinder passing signal, 209: Counter read bus, 210
: Speed adjustment signal, 211 : Adjustment operation end signal, 301
, 302: magnetic disk, 303, 304: read/write head. Applicant: H Mideki Co., Ltd. Agent: Patent Attorney: Toshimune Sumita

Claims (2)

[Claims] (1) A read/write head that mounts a magnetic disk plate and writes and reads information on the magnetic disk plate, and a magnetic head drive unit that drives the head using a head drive signal supplied from a servo control circuit described later. ,
a positioning information reading circuit that outputs head positioning information written on the disk plate read by the magnetic head to a servo control circuit described later; and a positioning control logic circuit that outputs the moving direction of the head, the number of moving cylinders, etc. , a head drive signal is supplied to the magnetic head drive section by the output of the positioning control logic circuit, and the head drive signal is corrected by a device determination information readout signal constituted by the positioning information readout circuit, thereby controlling the head position and head movement. In a servo surface servo type magnetic disk drive equipped with a servo control circuit that performs closed-loop speed control, a head movement start signal output from the positioning control logic circuit is input, and after a certain period of time from the start signal, the head movement start signal is inputted and the head movement start signal is moved for a certain period of time after the start signal. a timing setting circuit that outputs a window signal; a counter that counts the cylinder passing signal supplied from the servo control circuit during the window signal output from the timing setting circuit; and a counter that counts the output of the counter to a preset maximum value. A data conversion circuit that compares it with a high-speed electric value and outputs a speed adjustment signal to the servo control circuit, and a data comparison circuit that detects that the output of the counter is within a certain range and outputs an adjustment operation end signal. A magnetic disk device characterized by: (2) Feature 1: In the magnetic disk drive according to claim 1, the positioning control logic circuit, the timing setting circuit, the data comparison circuit, and the data conversion circuit are connected to a microprocessor and the microprocessor. A patent characterized in that it consists of a read-only memory