JPS59180859A - Speed controller of magnetic disk device - Google Patents

Abstract

PURPOSE:To attain a high-speed operation by controlling the speed of a magnetic head in accordance with the actual speed and the target speed based on the output of a cylinder pulse control means. CONSTITUTION:When a cylinder pulse is produced at a time point t1, the output of an OR circuit 10 is set at ''H''. Thus the pulse is applied to a control circuit 4, and the output of the circuit 10 is kept at ''L''. Thus no pulse is applied. In an acceleration mode one pulse is supplied to the circuit 4 for every two cylinder pulses. The pulse is applied to the circuit 4 at a time point t3; while no pulse is applied to the circuit 4 at a time point t4. In a constant speed mode one pulse is applied to the circuit 4 for every two cylinder pulses. The signal P2 is always set at ''H'' when the shift speed of a magnetic head 1 is reduced less than a fixed level at a time point t5. Therefore the output of the circuit 10 is kept at ''H'', and an AND circuit 11 applies the cylinder pulse as it is to the circuit 4. One pulse is produced for every plural cylinder pulses before the head 1 is set in a deceleration mode. Then the pulse equal to the cylinder pulse is produced in the deceleration mode to perform the speed control. Thus a high- speed operation is possible even with high density of a track.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in a speed control device for a magnetic disk device.

[Technical background of the invention]

An example of the configuration of a conventional device will be described with reference to FIG. 1 and FIG. 2Z. FIG. 1 is a block diagram of one configuration example, and FIG. 2 is a time chart illustrating its operation. The magnetic head 1 reads a positioning signal previously written on the medium and supplies it to the two-phase position signal generating circuit 2. Based on the positioning signal, the two-phase position signal generation circuit 2 generates two-phase position signals a and b, which are 90 degrees out of phase, as shown in FIG. . When the track pitch of the medium is half the period of the position signal a, the cylinder pulse generating circuit 3 is operated as shown in FIG.
), a cylinder pulse is generated that rises or falls at the zero cross of either position signal a or b. A control circuit 4 consisting of a microprocessor, ROM, etc. counts this cylinder nozzle and outputs a pre-stored target speed signal via a D/A converter 5.

Further, the speed signal generation circuit 6 obtains the actual speed of the magnetic head 1 by differentiating the two-phase position signals, and generates a speed signal corresponding to the actual speed. The speed signal and the target speed signal are subtracted in a summing amplifier 7, and based on this, the speed of the magnetic head 1 can be controlled by an actuator driver 8 and an actuator 9. That is, is the actual speed obtained from the speed signal generation circuit 6 the D/A converter 5'? : The control formula is controlled so that the control awn is controlled according to the target speed given through.

When the track pinch of the medium is 1/4 period of the position signal, the position signal a is as shown in FIG. 2(c).

A cylinder pulse that rises or falls at both zero crosses of b is emitted.

[Problems with background technology]

As mentioned above, in conventional devices, cylinder pulses are emitted in response to the magnetic head crossing tracks on the medium, and these pulses are counted and processed by a microprocessor, etc., so when the track density increases, Since the period of the cylinder Paris is shortened, there is a drawback that the magnetic head cannot be moved at high speed.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and provides a speed control device for a magnetic disk device that enables a magnetic head to operate at high speed even when the track Z density on a magnetic disk increases. The purpose is to

[Summary of the invention]

In order to achieve the above object, the present invention reads a positioning signal written in advance on a track on a medium by a magnetic head, and a cylinder that rises or falls in response to the magnetic head crossing the trunk. In a speed control device that determines the target speed of the magnetic head based on pulses and controls the speed of the magnetic head based on this target speed and the actual speed, the magnetic head that is currently moving on the medium from the track to the target track is Cylinder nozzle control means is provided for emitting one pulse for each plurality of cylinder pulses before entering a deceleration state to stop at the target track, and emitting the same nozzle as the cylinder Paris after entering the deceleration state. The present invention provides a speed control device for a magnetic disk device that determines a target speed of the magnetic head based on the output of this cylinder pulse control means and controls the speed of the magnetic head based on the target speed and the actual speed. .

[Embodiments of the invention]

The present invention will be described in detail with reference to FIGS. 3 to 8.

FIG. 3 is a block diagram of one embodiment, in which the same elements as in FIG. 1 are designated by the same reference numerals. The Norse P1 generated from the speed signal generation circuit 6 and the signal P2 generated from the processor and the like constituting the control circuit 4 are applied to an OR circuit 10, and the output of the OR circuit 10 is applied to one input of the node circuit 11. . A cylinder pulse is given to the other input of the AND circuit 11 from the cylinder pulse generation circuit 3.
The output of the ND circuit 11 is given to the control circuit 4.

FIG. 4 is a diagram explaining the relationship between the moving speed of the magnetic head l and the two-phase position signal, and FIG. 4 (a) shows the temporal change in the moving speed of the magnetic head l! 4(b) shows changes in the two-phase # signal.

When the magnetic head l located at the current track position on the magnetic disk starts moving toward the target trunk at time 1=0, the moving speed increases with time until time t=Tl.
The velocity becomes vO at . After that, when the vehicle moves at a constant speed until time t=T2, it approaches the target trunk and enters a deceleration state. Then, at time 2 T3, the magnetic head stops at the position of the target track.

In this way, the magnetic head l is in an accelerated state until time T1, is in a constant speed state from T1 to T2, and is in a constant speed state from T2 to T3.
Since it is in a deceleration state until time T1, the period of the two-phase position signal gradually becomes shorter until time T1, remains constant from T1 to T2, and gradually becomes longer from T2 to T3. Note that when the seek is short (when the current track and the target track are close), the constant speed state does not appear.

4 is a time chart illustrating the operation of the embodiment shown in FIG. 3 in a deceleration state. As shown in the figure, the pulse Pi emitted from the speed signal generation circuit 6 has two pulses, cylinder and pulse. Each time a pulse is given, one .xi.rus is generated, and is generated based on the positioning signal given from the two-phase position signal generating circuit 2. Further, the signal P2 emitted from the processor etc. that constitutes the control circuit 4 is
In the acceleration state and constant speed state, the level is low (hereinafter referred to as "L"), and when the speed becomes lower than a predetermined constant value after entering the deceleration state, the low level (hereinafter referred to as "H") is reached.
).

When the cylinder pulse is emitted at time t1, the output of the OR circuit 10 is 'H' at this time, so
A pulse is given to the control circuit 4.

When the cylinder pulse is emitted at time t2, the output of the OR circuit 10 remains "L" at this time, so
No pulse is given to the control circuit 4.

In this way, in the acceleration state, 1 pulse is applied to the control circuit 4 for every 2 pulses of the cylinder pulse.

At time t3, a pulse is applied to the control circuit 4 in the same manner as at time t1.

At time t4, no pulse is applied to the control circuit 4 in the same way as at time t2. In this way, even in a constant speed state, the cylinder pulse of 2 vA
9 pulses are given to the control circuit 4 for each pulse.

When the moving speed of the magnetic head 1 becomes less than a certain value at time t5, the signal P2 issued from the control circuit 4 is always "H", so the output of the OR circuit 10 becomes "H". Therefore, 1. The circuit 11 of υ now supplies the cylinder pulse as it is to the control circuit 4.

In this way, the track pitch is 1 of the two-phase position signal a.
/2 period, the cylinder pulse given to the control circuit 4 is 2 tracks in the acceleration state and the constant speed state. In the deceleration state, there is 1 point in the l-truck? Becomes Luz. Here, the reason why the pulse ke increases in the deceleration state is
This is to prevent the magnetic head 1 from overshooting.

FIG. 6 is a block diagram of another embodiment of the present invention, in which the same elements as in FIG. 3 are designated by the same reference numerals. Cylinder pulse is J
K Provided to the clock (CK) input of the flip-flop 12 and one input of the AND circuit 13. The Q output of the JK71 knob float 12 is applied to the other input of the AND circuit 13, and the output of the AND circuit 13 is applied to the control circuit 4. In addition, the J input and the input of the JK Fritz 12 are pulled up by a power supply (not shown), and the reset (PR) input and the clear (CLR) input are supplied with signals from the processor, etc. that constitute the control circuit 4. It will be done.

FIG. 7 is a time chart illustrating the operation of the embodiment shown in FIG. 6 when the magnetic head I is in an accelerated state, a constant speed state, and a decelerated state. As shown in the figure, in the acceleration state and constant speed state, the Q output of the JK frizz ratio becomes H every time two nogs of cylinder pulse are generated.
Control circuit 4 for 1 pulse per 2 cylinder pulses
can be given to On the other hand, in the deceleration state, J
Since the PR large input of the K frizzo flop is inverted from H'' to L'', the Q output is always H'' and is applied to the cylinder/gurusu trench control circuit 4.

FIG. 8 is a block diagram of another embodiment of the present invention, in which the same elements as in FIGS. 3 and 6 are designated by the same reference numerals. As a circuit that arbitrarily controls the number of pulses of the output (cylinder pulse) of the cylinder noculus generation circuit 3, the cylinder ? A pulse control circuit 14 is provided. The cylinder nox control circuit 14 is constituted by a combination of a counter, a flip-flop, and a gate, and outputs a nox signal similar to the AND circuit 11 of FIG. 3 and the likelihood circuit 13 of FIG.

〔Effect of the invention〕

As described above, according to the present invention, in a speed control device that controls the moving speed of a magnetic head based on the target speed of the magnetic head determined based on the cylinder nozzle and the actual speed, the speed control device moves from the current track on the medium to the target track. Before entering the deceleration state to stop the magnetic head moving up to the target track, one nogle is emitted for every multiple cylinder pulse pulses, and after entering the deceleration state, the same number as the cylinder pulse is emitted. ? A cylinder pulse control means for emitting pulses is provided, a target speed of the magnetic head is determined based on the output of the cylinder pulse control means, and the speed of the magnetic head is controlled based on the target speed and the actual speed. Therefore, it is possible to obtain a speed control device for a magnetic disk device that allows the magnetic head to operate at high speed even when the track density on the magnetic disk is increased.

Particularly, in the present invention, when the magnetic head approaches the target track and enters the deceleration state, the cylinder pulse is directly applied to the control circuit, so there is a unique effect that over-shooting is less likely to occur.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional device, and FIG. 2 is a time chart 1 for explaining the operation of the device shown in FIG. FIG. 3 is a block diagram of one embodiment of the present invention, FIG. 4 is a time chart explaining the relationship between the magnetic head and two-phase position signals, and FIG. 5 is a time chart explaining the operation of the embodiment of FIG. 3. , FIG. 6 is a block diagram of another embodiment of the present invention, FIG. 7 is a time chart explaining the operation of the embodiment of FIG. 6, and FIG. 8 is a block diagram of another embodiment of the present invention. . 10...OR circuit, 11, 13...simplified circuit, 1
2...JK flip-flop.

Claims (1)

[Scope of Claims] A magnetic head that reads a positioning signal written in advance on a track on a medium, and a circuit that generates a speed signal corresponding to the actual moving speed of the magnetic head based on the positioning signal. , a circuit for requesting a rising or falling cylinder pulse in response to the magnetic head crossing the track based on the positioning signal; and a target value for the moving speed of the magnetic head based on the cylinder pulse. A speed control device for a magnetic disk drive, comprising: a target speed circuit that issues a target speed signal corresponding to the speed signal; and means for moving the magnetic head from a current track on the medium to a target track based on the speed signal and the target speed signal. in which, before the magnetic head moving on the medium from the current track to the destination track enters a deceleration state to stop at the destination trunk, one noggle is emitted for each of the plurality of cylinder pulses; After entering the deceleration state, the cylinder 1'/'! Le;x, ,! : A speed control device for a magnetic disk drive, characterized in that the target speed circuit is equipped with a cylinder pulse control means for generating the same cylinder pulse, and the target speed circuit generates the target speed signal based on the output of the cylinder pulse control means. . 2. Speed control of the magnetic disk according to claim 1, wherein the cylinder pulse control means detects that the magnetic head has entered a deceleration state based on a signal corresponding to the actual moving speed of the magnetic head. Device. The magnetic disk speed control according to claim 1, wherein the three-cylinder pulse control means detects that the deceleration state has entered based on a signal corresponding to a target value of the moving speed of the magnetic head. Device.