JPS61224185A - Magnetic disk control device - Google Patents

Abstract

PURPOSE:To move a magnetic head in a stable floating attitude by providing a control circuit of a positioning mechanism with a filter means for reducing the oscillation of the magnetic head at the resonant frequency in the vertical direction. CONSTITUTION:The control circuit is formed by a counting circuit 11 counting the horizontal movement of the magnetic head with the track as the reference, a speed pattern generating circuit 12 generating a target speed pattern, a speed control circuit 13 controlling the speed of the magnetic head 3, notch filter circuits 15, 20 for reducing the vibrations of the high resonant frequency, a power amplifier 16 for applying the current to a voice coil motor coil 2, a positioning mechanism 17 formed by the voice coil motor coil 2 and the magnetic head 3, a circuit 18 for finding the deflection of the magnetic head from the center of the target track, a compensating circuit 19 forming a control signal moving the magnetic head based on the deflection and a filter circuit for especially reducing the large oscillation component out of the oscillation components in the direction perpendicular to the disk surface of the magnetic head. For transition and follow-up movements, the switch 21 is switched by a counter 22 and a switch changeover circuit 23.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a control device for a magnetic disk, and more particularly to a control device for controlling a positioning mechanism of a head support arm system having a head.

[Background of the invention]

A magnetic disk positioning mechanism includes a head support arm having a magnetic head at one end, and a guide arm that supports the head support arm in a cantilevered manner. When this positioning mechanism positions the magnetic head at a predetermined location on the magnetic disk, each part of the positioning mechanism vibrates in various vibration modes. In particular, the vibration that affects the positioning operation is the vibration at the resonant frequency, which has a high vibration level, and this becomes noticeable as vibration in the horizontal direction and vertical direction with respect to the disk surface of the magnetic head.

This may adversely affect positioning operations.

Conventionally, as means for reducing the above-mentioned vibration, for example, 19
“IEI!E Transactions on Magnetiques” (IEI!E) published in June 1978.
TRANSACTIONS ON M^GNETIC5
) Vol., MAG-14, Nn4, pages 178 to 181, it is stated that when a transition operation (seek operation) of a magnetic head to a target track of a magnetic disk is performed, this operation is performed so as not to degrade the performance of this operation. A notch filter centered at a resonant frequency fst, which is considerably higher than the crossover frequency f8 of the control circuit that causes this, is inserted into the control circuit to reduce vibrations at this resonant frequency. Furthermore, when following the target track (following operation), a notch filter centered at a resonant frequency fyt that is slightly higher than the crossover frequency f2 of the control circuit that performs this operation is inserted into the control circuit to suppress vibrations at this resonant frequency. It is disclosed that it reduces

However, in these conventional methods, the resonance frequency vibration to be removed tends to be limited to horizontal vibration of the magnetic head with respect to the disk surface.

Therefore, countermeasures against vibrations of the magnetic head in the direction perpendicular to the disk surface are not sufficient, and there is a risk that the magnetic head and the disk surface will come into contact under severe operating conditions.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic disk control device that can reduce the vibration level of the resonant frequency of the vibration perpendicular to the disk surface of the magnetic head and minimize the influence on the positioning operation of one positioning mechanism.

[Summary of the invention]

In order to achieve the above object, the present invention provides a magnetic disk equipped with a head positioning mechanism system having a head support arm having a magnetic head at one end and a guide arm supporting the head support arm in a cantilever shape. , to the control circuit of the positioning mechanism system.

A filter means is provided for reducing vibrations at the resonant frequency of vibrations perpendicular to the disk surface of the magnetic head that occur during positioning operations of the magnetic head.

With this configuration, the magnetic head can be shifted in a stable flying posture.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of a magnetic disk positioning mechanism equipped with an example of the apparatus of the present invention, which is called a one-rotation type mechanism. In this figure, 1 is the magnet of the voice coil motor, and 2 is the voice coil bobbin. 3 is a plurality of magnetic heads; 4 is a head support arm that supports each of the magnetic heads 3; and 5 is a guide arm that supports each of the head support arms. The voice coil bobbin 2 and the guide arm 5 are coupled and integrated by a carriage 6. The carriage 6 is a rotation bearing 8 of the base 7.
It is rotatably supported by.

By applying a current to this voice coil 2, the magnetic head 3 is swung in a horizontal plane along the magnetic disk surface 9, positioned on concentric tracks recorded on the magnetic disk surface, and read and written magnetic information. do.

FIG. 2 is an enlarged view of the head support arm 4 and guide arm 5 of the magnetic disk. The numbers in the figure indicate the same parts as in Figure 1. When a current is applied to the coil 2, the coil 2 moves as shown by the arrow and the entire body swings around the rotational shaft load, positioning the magnetic head 3 at an arbitrary position. As shown in Figure 0, the coil 2 has a structure in which electric wire is wound, and the guide arm 5 is connected to the head support arm 4 in order to improve the positioning speed.
is lightweight and has a vibration mode with a relatively low resonant frequency. This vibration mode is suitable for high-speed positioning operations on the order of milliseconds, which involves not only vibrations that move the tip of the guide arm 5 in the (horizontal) direction along the disk surface, but also vibrations that move the tip of the guide arm 5 in the direction perpendicular to the disk surface. A considerable acceleration is applied, and the tip of the guide arm 5 vibrates horizontally and vertically to the disk surface, affecting the first positioning operation.

Therefore, the head support arm 4 and the connection between the head support arm 4 and the magnetic head 3 are devised so that this vibration does not directly inhibit the movement of the magnetic head 3.

3 and 4 are enlarged views of the head support arm 4 and the magnetic head 3. FIG. The head support arm 4 is molded from an extremely thin metal plate. The base A of this arm 4 acts as a leaf spring to absorb and cut off vibrations, and the magnetic head 3 is attached to a gimbal 10 made of a thin metal plate.
It is attached to the tip B of the head support arm 4 via.

This cymbal 10 acts as a leaf spring to absorb and cut off vibrations. Through these functions, even if the magnetic head 3 is moved at high speed during seek, the force applied to the magnetic head 3 is alleviated. to maintain a stable floating position. Further, even if the magnetic disk disk 9 vibrates in a direction perpendicular to its surface during rotation, the flying height of the magnetic head 3 is maintained constant by its action.

FIG. 5 shows the circuit configuration of the control device of the present invention. The operation of positioning the magnetic head 3 to the target track has the following two roles, and the respective control circuits function as follows.

First, the transition operation (
During a seek operation), the switch 21 is on the S side. 11
12 is a counting circuit that counts the horizontal displacement of the magnetic head 3 with the track as a reference, and 12 is a speed pattern generating circuit 13 that generates a target speed pattern for the counted number of tracks. A speed control circuit 15 controls the speed of 3, and a notch filter circuit 15 reduces vibrations at a resonance frequency fax that is considerably higher than the crossover frequency f of this control circuit.

16 is a power amplifier for applying current to the voice coil motor coil 2 based on the above control signal.

Reference numeral 17 denotes a positioning mechanism comprising the voice coil motor coil 2, magnetic head 3, etc. shown in FIG. Reference numeral 14 denotes a filter circuit newly provided in order to reduce specific imaging to be described later.

Next, during the following operation for the target track, the switch 21 is on the F side.

18 is a circuit that determines the amount of deviation of the magnetic head from the center of the target track; 19 is a compensation circuit that generates a control signal to move the magnetic head based on this amount of deviation; 20 is a circuit that calculates the amount of deviation of the magnetic head from the center of the target track; a notch filter circuit for reducing the imaging of high resonant frequencies f Pi;
14 to 17 are the same circuits as described above. The above-mentioned switch 21 is connected to the counter 22. The switching is performed by the switch switching circuit 23.

FIG. 6 shows the configuration of a notch filter as an example of a newly provided filter circuit 14 for reducing specific vibrations used in the device of the present invention.

OPl and OF2 are operational amplifiers. In this circuit, by appropriately selecting the RCC, it is possible to output a signal in which frequency components in the vicinity of a certain frequency are reduced from the input signal.

FIG. 7 shows an example of the frequency distribution of the vibration amplitude in the direction perpendicular to the disk surface of the magnetic head 3 when the filter circuit 14 in FIG. 5 is not used. As shown in this figure, there is vibration near 3KH1 that greatly affects the positioning operation.

FIG. 8 shows an example of the frequency distribution of the vibration amplitude in the direction perpendicular to the disk surface of the magnetic head 3 when the filter circuit 14 in FIG. 5 is used. Filter circuit 14
In the notch filter circuit shown in Fig. 6,
R=24.1 kΩ.

It is C-2200pF. As a result, the output signal from this notch filter circuit has fewer frequency components around 3 KHz. As a result of this,
Vibration around 3 KHz, which was noticeable in FIG. 5, is reduced.

【Effect of the invention〕

According to the present invention, among the vibration components of the magnetic head in the direction perpendicular to the disk surface, it is possible to reduce the vibration component that is particularly large in the positioning operation. As a result, even if the positioning mechanism is driven with a large acceleration during a seek operation, the vibration of the magnetic head can be suppressed to a small level, so that the magnetic head can be shifted in a stable flying posture. Therefore, contact between the magnetic head and the disk surface can be prevented even under severe operating conditions, enabling high-speed and highly accurate positioning operations, and is highly effective in improving the reliability of the magnetic disk drive.

[Brief explanation of drawings]

FIG. 1 is an external view of a positioning mechanism of a magnetic disk drive including an example of the device of the present invention, FIG. 2 is an enlarged view thereof, FIGS. 3 and 4 are a plan view and a side view of a head support arm,
FIG. 5 is a block diaphragm showing the circuit configuration of a control device for head positioning of a magnetic disk drive including a filter circuit of the present invention, and FIG. 6 is a circuit diagram showing the configuration of a filter circuit that is an embodiment of the present invention. , FIG. 7, and FIG. 8 are frequency distribution diagrams showing the vibration characteristics of the magnetic head. DESCRIPTION OF SYMBOLS 1... Voice coil motor magnet, 2... Voice coil bobbin, 3... Magnetic head, 4... Head support arm, 5... Guide arm, 6... Carriage, 7... Base , 8... Rotating bearing, 9... Magnetic disk disc. 10...Gimbal, 11...Counting circuit, 12...
Speed pattern generation circuit, 13... Speed control circuit, 14
... filter circuit, 15 ... notch filter circuit,
16... Back amplifier, 17... Positioning mechanism, 18
... deviation amount detection circuit, 19... compensation circuit, 20...
・Notstifil 岡 2nd hole 30 Tsukiyoshi Otsuko Akira iIL Ei KH1 #7 Saka Ei KHl

Claims (1)

[Scope of Claims] 1. A magnetic disk comprising a positioning mechanism having a head support arm having a magnetic head at one end and a guide arm supporting the head support arm in a cantilever shape, a control circuit for the positioning mechanism. 1. A control device for a magnetic disk, characterized in that a filter means is provided for reducing the resonance frequency of the vibration of the magnetic head in a direction perpendicular to the disk surface, which occurs during a positioning operation of the magnetic head. 2. The filter means is a filter circuit that reduces the vibration resonance frequency of the head support arm that is related to the resonance frequency of vibration of the magnetic head in a direction perpendicular to the disk surface. A magnetic disk control device according to scope 1. 3. Claims characterized in that the filter means is a filter circuit that reduces vibrations at a resonance frequency of vibrations of the guide arm related to resonance frequencies of vibrations of the magnetic head in a direction perpendicular to the disk surface. 2. The magnetic disk control device according to item 1. 4. The magnetic disk control device according to any one of claims 1 to 3, wherein the filter means is a notch filter whose center frequency is the resonance frequency of vibration. 5. The magnetic disk control device according to claim 4, wherein the notch filter has a variable and adjustable center frequency.