JPS62195773A - Magnetic recording device - Google Patents

Abstract

PURPOSE:To accurately position a data head on a target track within a short time by storing beforehand a correction value obtained from the positional information of data plane, correcting a positional signal obtained from the positional information of servo plane with the said correction value, and using a resulting signal as a positional error signal. CONSTITUTION:The second positional signal detected by a data head 11 is supplied to a positional deviation detecting circuit 13 through a positional signal reproducing circuit 12. The circuit 13 has a function of holding a signal, and when a detection instruction is supplied, detects a new positional deviation by inputting the difference value between the positional error obtained from the data plane and that outputted from a positional error difference detecting circuit 16 on the servo plane-side, holds the new deviation until the following detection instruction is supplied, and outputs it. this output represents the difference between the distance between a data head and the target data track and the distance between a servo head and a servo track. Accordingly, said output is made a correction value to correct the first positional error signal obtained from the servo head 14.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a head positioning method for a magnetic recording device, that is, an improvement in a method for accurately positioning a data head on a predetermined data track.

[Conventional technology]

A magnetic recording device has a conversion system consisting of a magnetic disk on which data is recorded (hereinafter referred to as the disk) and a magnetic head (hereinafter referred to as the head) that records and reproduces information on the disk. It is fixed to the FM structure for movement and positioning. A large number of concentric data recording areas called tracks are provided on the disk, and by moving the head onto these tracks,
Information is recorded and reproduced between the disk and the head.

Therefore, in order to efficiently and accurately record and reproduce information,
It is necessary to accurately position the head on the track.

As the track density increases and the track width decreases, more accurate positioning is required. For this reason, position information is recorded on the disk, and the head is tracked accurately according to the position signal reproduced by the head. A servo system with controlled positioning is widely used.

Conventionally, there are several types of servos, but due to the low positioning accuracy and short positioning time, one of the recording surfaces of the disk is dedicated to recording position information for positioning control. Many methods have been adopted in which the remaining surface is used to record only data. The control-only surface on which this positional information is recorded is called the servo surface (servo disk surface), and the surface on which only the remaining data is recorded is called the data surface (data disk surface). These two disks are fixed to a spindle motor and rotated. In this method V), the magnetic recording device has two types of heads: a head corresponding to the servo surface (referred to as a servo head) and a head corresponding to the data surface (called a data head). Each of these heads μ is looked into by a support arm, and the support arm is movable in the radial direction of the disk and is fixed to a positioning device using a VCM (voice coil motor) or the like as a driving motor. The position signal obtained from the servo head is monitored, and the VCM is controlled so that the deviation between the servo head position and the target track position becomes small. It was positioned at

However, according to the above θ method, although it is possible to accurately align the servo head and the servo track, it is not necessarily possible to accurately align the data head and the target data track.

In other words, the support arm between the servo head and the data head, the positioning g & inertia section, and even the main shaft motor may become misaligned or tilted due to the operation of various parts or changes over time.
Mainly, the positioning mechanism, the spindle motor, and the base frame to which these two mechanisms are fixed may tilt or deform due to temperature changes, or temperature differences may occur between stacked disks. Due to reasons such as a difference in expansion density, a difference occurs between the relative positions of the servo head and the servo track and the relative positions of the data head and the target data track.

As a result, even if the servo head is accurately positioned on the target servo track, the data head will deviate from the target data track.

Therefore, in order to solve this problem, Japanese Patent Application Laid-Open No. 51-816
As described in 03, positioning is performed using the first position signal obtained from the servo head, and then a correction value of 1 kW is obtained from the second position signal obtained from the data head.
Superimposed on the position signal of c1.

A method was taken to accurately position the data head over the target data track.

[Problem that the invention seeks to solve]

Although the above method allows the data head and the target data track to be correctly aligned, new problems have arisen as described below. Namely.

If the above improvement had not been made, positioning would have been performed only using the 117th position signal from the servo head, but with the above improvement, positioning was first performed using the 10th position signal from the servo head, and then, Furthermore, since fine adjustment is performed using the second position signal obtained from the data head, additional positioning time is required for this fine adjustment.Furthermore, this second position information is not recorded on the data track. For example, if only one location is recorded -6,-, the data head will start recording the second location information from the moment the position control based on the first location information is switched to the location control with the second location information superimposed. Before reading the data and actually starting control, a waiting time is required equal to the time it takes for the second position information on the data surface to rotate to the data head. If the second position information is recorded at only one location on the track, the physical waiting time is equal to the time it takes for the disk to make one-half revolution. Furthermore, if a large number of positional information are recorded on a data track, the above-mentioned waiting time will be shortened, but it will not essentially be improved.

FIG. 5 is drawn to explain how the displacement of the data head with respect to the target data track changes with the passage of time when determining the Q and #. In FIG. 5, the solid line graph 28c represents the change in displacement over time when correction is performed using the second position information as described above. The broken line indicated by 31 is the track position based on the first position information, and after the head moves with this as a target, it makes a vibrational transient response and then converges to the target position indicated by 31 ( The settling time 32 for the convergence of this transient response is called settling, and the second
Waiting time until the location where the position information is recorded rotates to the data head location 33 Time for the next fish to move to the data track based on the correction value Ah, after positioning the data head on the data track A settling time of 35.04 different operating times is required.

Without the above-mentioned improvement, positioning would be completed within settling time 32, which would significantly increase the overall travel time.

As described above, the improved method has the disadvantage that the head positioning time is long, and it is incompatible with devices that have been increasing in speed in data retrieval and transfer in recent years.

[Means for solving problems]

A servo disk surface on which 11D position information is recorded as a control signal for positioning the data head on the target data track, and one or more surfaces on which second position information is recorded together with the data area on the data track. a servo head having a data disk surface and attached corresponding to the servo disk surface; and a servo head attached corresponding to the data disk to record and reproduce data and reproduce the second position information. One or more data heads, a head positioning mechanism section for attaching, moving and positioning the servo head and the data head, and controlling the positioning of the data head to the target data track based on the position information of the @1 and the beast 2. In a magnetic recording device having a control unit, the second position information recorded on the data disk surface, or if there is a plurality of data disk surfaces, the second position information recorded on one or more data disk surfaces.
No.1 information@ft, detect as appropriate in states other than startup.

From the obtained second position signal and the first position signal obtained from the servo disk surface on which the first position information is recorded, the positional deviation between the data head and the target data track and the servo head are determined. A signal corresponding to the difference in positional deviation between the servo track and the servo track is detected and stored as a correction needle, and when positioning the data head cJ, the first position signal obtained from the servo disk is used as the correction needle. The correction is made by superimposing the 0 position signal on the 0 position signal, and positioning is performed using the O position signal after the correction.

[Effect]

According to the present invention, the second position information for which the first position information is to be corrected is read out in advance by the data head and stored as a correction value before seeking, and the correction value obtained in advance is used at the time of seek. Direct positioning at the corrected position (2) requires a short time for positioning, and since the correction is performed using the second position information (3), each data head is accurately positioned on the target track.

〔Example〕

A first embodiment of the invention vi - described below.

Figure 1 is a conceptual diagram of the mechanical system of this embodiment. A disk is attached to the main shaft motor 3 and is rotating, and the lower recording surface of the disk is the servo surface 1. Remaining side or data side 2 (2 cL ~ 3 g)
A servo head 4 and a data head 5 (5α to 5g) are provided as heads corresponding to the respective heads. Each of these heads is fixed to a support arm 6,
Furthermore, the support arm is attached to the head positioning machine m section 7. This is a head drive motor. When the voice coil motor (VC:M) of No. 8 rotates around the axis lO, the servo head and data head attached to the head positioning mechanism section make the same movement in the disk radial direction.

In ζζ, as described above, the first position information on the servo surface is reproduced by the servo head, and the data on the data surface and the position information of Ka2 are reproduced by the data head. FIG. 2 shows a conceptual diagram of a row of data recorded on the data surface and the second v position information.

A large number of data tracks D1 to D3 and servo tracks S l-S are arranged on the data surface 2, and the boundaries of adjacent servo tracks coincide with the radial center of the data tracks. In this embodiment, the servo tracks are arranged only at one location on the data track, but there is no problem even if there are servo tracks at two or more locations.

FIG. 3 is a conceptual diagram of a position control circuit for loading and unloading a magnetic disk in this embodiment, and its operation will be explained below.

14 is a servo head, and detects the first position information recorded in Servo Co., Ltd., and in a position signal reproducing circuit of 15, after passing the AGO through an i-fit that does not cause position detection errors due to changes in signal amplitude. , a necessary position signal is separated from the servo signal, and from this signal, a position difference detection circuit 16 determines the servo head and servo track error.

On the other hand, the second position signal detected by the data head 11 is similarly supplied to the position deviation signal detection circuit 13 via the position signal reproducing circuit 12. The position error detection circuit 13 has a signal hold function, and when a detection command is given, it detects the difference between the position difference obtained from the data surface and the device error constituted by the position error detection circuit 16 of the servo surface sensor 1. It inputs a new positional deviation and outputs it while holding it until the next detection command is given. This output represents the difference between the distance between the data head and the target data track and the distance between the servo head and the servo track, and serves as a correction for correcting the first position error signal obtained from the servo head.

As described above, the first position information on the servo surface and the position information on the data surface 2 are added to the adder 17, and become a corrected position error signal.

Now, after the position information obtained from the servo surface passes through the position signal reproducing circuit 15, it follows another route. The position signal differentiated by the differentiating circuit 21 becomes a speed signal and is applied to the electronic tachometer 4. On the other hand, the accent tachometer 22 has %
A signal obtained by detecting the drive current flowing from the VCM drive circuit 18 to the VCM 19 and integrating it at an integrator station is also added. Using the speed signals of the two heels inputted to the electronic tachometer 22f'i, it outputs a speed signal with a good 8/1J ratio over a wide frequency band. During a seek, when you press i, the CPU calculates the speed according to the number of remaining tracks to which the head should further seek (specifically, proportional to the square root of the number of remaining tracks).
The signal obtained by converting this value by the speed reference signal generating circuit δ becomes a speed reference signal, and is used as a reference for the head to move at this speed.

The output of the attenuator tachometer 22+2) and the speed reference signal are applied to the adder B, and the difference between the two is output as a speed error signal.

As explained above, the adder 17 outputs the corrected position error signal, and the adder B outputs the speed error signal. During the seek operation, the movement operation is speed controlled except for the final stage positioning control. Therefore, SWl is opened and only FLs w is closed, and only the speed error signal from the adder Okara is applied to the vCM drive circuit 18 iL, VCML
drive the head system 14 via the positioning mechanism section 20.
and 11vi-move. On the other hand, when the number of remaining tracks to be moved becomes less than 1 track, the data head is correctly positioned on the target data track by one-position control in which speed control is switched to position control. For this purpose, SW- is opened and aWl is closed, and thereby a position error signal corrected with the previously held position signal of the spear 2 is input to the drive circuit 8, which controls the VCM 19 to set the data head 11 to 1. By repeating Ifil control, the target data track can be accurately positioned in a short time.

FIG. 4 shows a conceptual diagram of a circuit according to a second embodiment of the present invention.

The basic operation is the same as in the first embodiment, but the processing of the second position information obtained from the data head is different.

That is, the position information obtained from the data head 11 is 1
The signal passes through the position signal reproducing circuit 12 and the position deviation signal detecting circuit 13 and then enters the averaging circuit 27.

In the averaging circuit n, every time a sampling command pulse is input, all position error signals are input, and while the 16 pieces of data from the newest are held, the data before the 17th from the newest are discarded, and the data is processed in the order of the newest. The average value of up to 16 pieces of data is determined and output as a correction value while being held until the next sampling command pulse is input. By averaging the 16 position error signals, it is possible to output a position correction signal with a smaller error Q due to irregular disc radial deviations and vibrations to the adder 17, improving correction accuracy. The circuit configuration and operation other than this are the same as the embodiment shown in FIG.

〔effect〕

As described above, according to the present invention, the correction obtained from the position information on the data surface is stored in advance, and the position signal obtained from the position information on the servo surface is corrected with this correction to generate a position error signal. Since the data head is used as a target track, it is possible to accurately position the data head on the target track in a short time.

FIG. 5 shows a graph in which the Q effect of the present invention can be seen. The dotted line graph is a line showing the temporal change in the displacement of the data head when the positioning control according to the present invention is used. As seen in this figure, the positioning is completed after only one settling time of 36% after the positioning has progressed with the same amount of displacement as that of the conventional array until just before positioning. It is possible to significantly shorten the time and therefore speed up data retrieval.

[Brief explanation of drawings]

Figure 1 is a schematic diagram showing the configuration of the mechanism part of the embodiment of the present invention,
Figure 2 of the sail is one of the fruits of this invention! A diagram schematically showing the arrangement of data tracks and servo tracks on the data surface of the f1 example,
Figure 3 is a diagram showing the circuit configuration of an embodiment of the present invention, Figure 4 is a diagram showing the circuit configuration of another embodiment of the invention, and Figure 5 is a diagram showing the effect of shortening the positioning time according to the present invention. be. 1...Servo surface 2 (2cL ~ 2g) @s data surface 3...Spindle motor 4...e Servo head 5 (5α ~ 5g)...Data head 6...Support arm 7...Head positioning mechanism section 8...- Voice coil motor (VCM) 9...Base frame...Axis 11...Data head 12 @-Position signal regeneration circuit 13...Position deviation detection circuit 14-e servo head 15...Position signal reproduction circuit 16#-Position Error detection circuit 17・e adder 18・・VCM drive circuit 19・・VCM addition/0 head positioning mechanism 21・・differentiator 22@, electronic controller・・adder U・・CPU 5・・・Speed reference signal generator A...Integrator 4...Averaging circuit A...Graph 29 showing an example of the displacement of the data head from the target data track with respect to time changes when positioning is performed using conventional technology. Graph I showing an example of the displacement of the data head from the target data track with respect to changes in time when positioning is performed according to the present invention.Target data track position 31.The data head is moved by the first position information on the servo surface. Positioned position 32, settling time, waiting time 34, self-moving time 35, settling time 36, settling time or more Applicant Seiko Epson Floor Type Company Figure 1-

Claims (1)

[Claims] A servo disk surface on which first position information is recorded as a control signal for positioning the data head on a target data track, and one or more surfaces on which second position information is recorded together with a data area on the data track. a servo head having a data disk surface and attached corresponding to the servo disk surface; and a servo head attached corresponding to the data disk and recording and reproducing data and reproducing the second position information. a head positioning mechanism unit that attaches, moves, and positions the servo head and the data head;
In a magnetic recording device having a control unit that controls the positioning of the data head to a target data track based on the first and second position information, the second position information recorded on the data disk surface, Alternatively, if there are multiple data disk surfaces, the second position information of one or more surfaces is appropriately detected in a state other than startup, and the obtained second position signal and the first position information are From the first position signal obtained from the recorded servo disk surface,
a positional deviation between the data head and the target data track;
A signal corresponding to the difference in positional deviation between the servo head and the servo track is detected and stored as a correction amount, and when positioning the data head, the signal is applied to the first position signal obtained from the servo disk. A magnetic recording device characterized in that positioning is performed using a position signal after superimposing the correction amount.