JPH0479079A - Head positioning signal generating method and device and head positioning device - Google Patents

Abstract

PURPOSE:To improve the reliability of a seek operation by forming two small servo patterns, at least, in a servo pattern discretely embedded in a peripheral direction in a recording medium, generating an extended position signal by using a head position information recognizing means and a central processing unit, and using the signal when rushing into a target track. CONSTITUTION:By using two servo patterns at least formed at a servo sector, a head position information recognizing means 10 recognizes and discriminates the relation between relative positions to the information track of a data head to the 1/(2N) width of the track. By using the output of the head position information recognizing means 10 and a central processing means (CPU) 101, a head positioning signal generator 100 calculates a distance in the radial direction of the recording medium between an arbitrarily decided track and the head with the 1/(2N) resolution of the track width and generates a head positioning signal having the M tracks of the dynamic range with the M tracks as the cycle according to the calculated value. Thus, probability can be decreased for sequence error such as overrunning or reversing to the track.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method and apparatus for recognizing head position information and a head positioning method and apparatus when making a data head access an arbitrary information track on a rotatable recording medium. Conventional technology Conventional magnetic disk drives have widely adopted a servo surface servo method that positions the head to a target data track based on servo information written on the surface of the recording medium. The positioning of the data head is performed based on a relationship of trust with Writing servo information on the data surface The data surface servo method is attracting attention because it improves reliability during recording and playback.

One of them is the sector servo method. In this method, a servo sector for positioning is embedded in advance at the beginning of each sector on the data surface, and when an arbitrary data track is selected, the head follows each data track based on the servo information of the servo sector. It is. However, with this method, the servo sector only has information for track following control.In order to move the head at high speed, it is necessary to install a separate position detector.The head position information must be supplied from the servo surface. It has the disadvantage that it cannot be used. In addition, if you try to obtain sufficient position information even during high-speed access using only the servo information of the servo sector, the ratio of the servo sector to the data sector on the recording medium surface will increase, resulting in a significant decrease in storage capacity. There is.

Therefore, a method has been proposed in which a track number is coded and recorded in a servo sector, and the head is accessed based on this information.

(Jikou No. 51-131607) This method (obtains discretely the position information (address information) of the track that the head passes during seek, and compares the average speed between sectors with the bundle number command speed. The speed is controlled by the following method.It has been widely used recently because it is mechanically simple and has good cost performance even when the number of recording media to be stacked is small.

Problems to be Solved by the Invention A method of encoding track numbers and recording them in servo sectors on the surface of a recording medium. The resolution of the track position information obtained is only one track at most.
The speed detection error △Vit,) Rack width is x
If t p and the interval between servo sectors are Ts, it is expressed as tp ΔV = Ts and corresponds to about a few centimeters to ten cm/s. In the transient state when switching from seek operation to follow-up control operation, it is necessary to adequately control the head movement speed to about 1 to 3 cm/s to enable stable entry into the target track. However, it is very difficult to control the moving speed of the head when there is a detection error of several cm/s.In addition, the dynamic range of the position signal when entering the target track is usually ±l.
It is only about /2 track t°C.The conditions for the head entry speed in order to stably draw the head into the target track are low and limited. As a result, the head greatly overshoots or undershoots the target track, and it takes time to adjust to on-track.4 Also, if the speed is even slightly too fast, a seek error may occur, which can be a fatal defect. ~ In other words, there are major issues with the head position detection accuracy during seek and the dynamic range of the position signal during tracking control, which is a major issue in improving the performance of the entire head positioning device.

Additionally, as the recording density on a recording medium improves, the number of information tracks increases when encoding the track numbers mentioned above.
A large area will be required.

In other words, although the ratio of the servo area to the data area on the recording medium is increasing, making it difficult to secure a large capacity, there are ways to solve this problem. The invention includes the following method or structure. In other words, a servo pattern is formed discretely in the circumferential direction of a rotatable recording medium.
The servo pattern (consisting of at least two small servo patterns of the friend M track period (M is an integer of 2 or more),
The peak values of the reproduced signal amplitudes of the respective servo patterns are compared to obtain first binary information, and then at least one of the peak values of the reproduced signal amplitudes is determined according to the value of the first binary information. After adding the first offset, the respective peak values were compared again to create the second binarized information, and the offset was added according to the value of the second binarized information. Add a second offset to the peak value L or 1 yo Second 2
When creating the digitized information, a different offset from the first time is added to the peak value to which no offset was added, and each comparison is performed again to create the third digitized information.
Furthermore, by continuing the above operation up to at least the Nth (N is an integer) position, the position of the head in the radial direction of the recording medium can be recognized minutely to 1/(2'') of the track width, and the arbitrarily determined track and head can be recognized. The distance in the radial direction of the recording medium is
A method of calculating with a resolution of 1/(21') of the track width and generating a head positioning signal with a cycle of M tracks and a dynamic range of M tracks according to the calculated value above. A servo pattern is formed discretely in the circumferential direction, and the servo pattern is composed of at least two small servo patterns of i!M track period (M is an integer of 2 or more), and the peak value of the reproduced signal amplitude of each of the small servo patterns is at least two peak holder elements that each store, and at least one that compares the at least two peak values, respectively.
one comparison element, a first latch element that stores the output of the comparison element and holds the first binarized information, and determines which peak holder element to add an offset to according to the contents of the first latch element. An offset decoder element that adds an offset to a predetermined peak holder element based on the command of the offset decoder element, and an offset addition element that adds an offset to a predetermined peak holder element based on the command of the offset decoder element, and a comparison element that again compares the peak holder element to which an offset is added and the peak holder element to which no offset is added. a second latch element that temporarily stores the result and holds the second binarized information; and N latch elements that latch the Nth to Nth binarized information; Using the contents of the first latch element to the Nth latch element, the relative positional relationship of the data head to the track is determined by 1/(
head position information recognition means comprising a head position information discriminating element that detects up to 2N);
The distance in the recording medium radial direction between an arbitrarily determined track and the data head is calculated with a resolution of 1/(2N) of the track width, and head positioning is performed with a period of M tracks and a dynamic range of M tracks according to the calculation result. A power composed of a central processing unit (CPU) that generates signals
or (Y) a discrete servo pattern formed in the circumferential direction of a rotatable recording medium, a data head capable of reproducing at least information on the recording medium, and a reproduction signal of the data head that generates the discrete servo pattern. servo information demodulation means for extracting servo information contained in the data head; head position information recognition means configured to minutely recognize the relative positional relationship between the data head and the track down to 1/(2N) of the information track width; A head positioning signal generating device according to claim 2, wherein the processing means (CPU) is configured to generate a head positioning signal having a cycle of M tracks and a dynamic range of M tracks, and an output of the head positioning signal generating device. speed command means for outputting a track access speed command according to the distance to the target track; speed recognition means for determining the moving speed of the data head in the radial direction of the recording medium; The track following control is configured by feeding back at least a signal based on the output of the head positioning signal generating device to the positioner means, and the track access control is configured by controlling the speed of the speed command means and the speed recognition means. The method and apparatus for generating a head positioning signal and the head positioning apparatus of the present invention generate a servo pattern in the circumferential direction on a recording medium by the method and apparatus described above. The servo pattern is formed discretely and includes at least two small servo patterns of M track periods (M is an integer of 2 or more).The two servo patterns are used to determine the relative positional relationship of the data head to the track. The distance in the radial direction of the recording medium between the arbitrarily determined track and the head is detected down to 1/(2N) of the track width.
According to the calculated value, it is possible to generate a head positioning signal with a period of M tracks and a dynamic range of M tracks.As a result, the dynamic range of the position signal is expanded many times, and the head moves at high speed. This makes it possible to pull in stably even if the target truck is entered. Sunawazaka Faster, shorter time α
Although it is possible to achieve more reliable track seek (access) performance, the servo information formed on the recording medium (ordinary binarization processing) is limited to the head position up to the same resolution as the information track width. Unrecognizable and ±
With a position signal having a dynamic range of about 1/2 track, the head movement speed when pulling the head into the target track must be limited to a low level. In the conventional method, not only is it not possible to adequately control the moving speed of the head in the transition state from the Ct seek state to the tracking control state, but also the head entry speed to the target track is limited to a low level, and the ability to pull the head into the target track is high. However, the head positioning signal generation method and device of the present invention and the head positioning device ζ can improve the position recognition resolution many times compared to the conventional method, and the speed detection resolution during air intake seek. As a result, the moving speed of the head to enable stable entry into the target track can be sufficiently controlled to about several cm/s. -1, with a period of M tracks, M
It is possible to generate a head positioning signal having the dynamic range of the track, and the dynamic range of the position signal is expanded many times.Even if the head enters the target track at high speed, it can be stably pulled into the target track. In other words, the plate allows you to enter the target track at high speed.The seek time can be shortened. It also prevents overshoot and undershoot when transitioning to track following control and shortens the settling time.In addition, it reduces the probability of seek errors such as overrunning the track or going backwards, and improves seek operation. DESCRIPTION OF THE PREFERRED EMBODIMENTS A method and apparatus for generating a head positioning signal and a head positioning apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a basic block diagram of a head positioning device in one embodiment of the present invention. Figure East 1 is a rotatable recording medium such as a magnetic disk and a spindle motor (not shown).
Rotate by. Reference numeral 2 indicates a servo sector which is discrete in the circumferential direction and records servo information embedded (recorded) in advance on the surface of the recording medium. Reference numeral 3 indicates a data sector in which data is recorded.

4 is an information track provided on the surface of the recording medium, 5 is a data head that can read and write information on this information track, and 6 is a VCM positioner (VCM positioner) that moves (accesses) this data head to a selected information track. 7 is an amplifier that amplifies the reproduced signal from the data head. 8 is a servo information demodulator 10 that detects servo sectors that exist discretely from the reproduced signal and extracts the information. At least two head position information recognition means for recognizing and determining the relative positional relationship of the data head to the information track using two servo patterns up to 1/(2°) of the track width; 100 is the output of the head position information recognition means and central processing; Means (CPU)
101, the distance in the radial direction of the recording medium between an arbitrarily determined track and head is calculated as 1/(2) of the track width.
A head positioning signal generating device calculates with a resolution of N) and generates a head positioning signal having a period of M tracks and a dynamic range of M tracks according to the calculated value. 11 moves the data head to the selected information track (access) To track access control special number
This is a speed command device that commands a target speed according to the distance to the target track or the number of tracks to the target track. Normally, the speed command is a force realized by a ROM table, etc. (It may be a function that calculates and outputs each time the distance to the target track or the number of tracks to the target track is measured. A speed detector that calculates the moving speed of the data head in the radial direction of the recording medium by inputting high-resolution head position information every time it passes through a servo sector.When detecting the speed, only the output from the head position information recognition means is used. It is also possible to use the current flowing through the VCM positioner (-13 is the speed command 1 above).
This is an error amplifier that calculates an error between the outputs of the speed detector 1 and the speed detector 12. The output of this error amplifier 13 is supplied via a compensator 14 and a switch 16 to a current driver 17 that supplies current to the VCM positioner according to the output of the compensator 14, thereby configuring a track access control loop. A tracking control loop 1 that causes the data head to follow an information track outputs the output of the head positioning signal generation device 100 to the current driver 1 via a compensator 15 and a switch 16.
7.

As can be understood from the basic block diagram of FIG. 1, the head positioning signal generation method and device of the present invention and the head positioning device (Muta) relate to position recognition, positioning signal generation, and speed control in track access (seek) of a data head. It mainly uses servo patterns of M track periods (M is an integer of 2 or more) embedded discretely in the circumferential direction of the recording medium to determine the relative positional relationship of the tracks that the data head passes. 1/(2″) of track width
A method and apparatus for generating a head positioning signal having a period of M tracks and a dynamic range of M tracks using head position information recognition means that detects with a resolution of is involved in As a result, the speed of the data head can be sufficiently controlled to several cm/s in a transient state when switching from a seek operation to a follow-up control operation. In addition, even when the target track is entered at high speed, it is possible to shift to follow-up control operation using a position signal with a wide dynamic range, which prevents overshoot or undershoot of the data head and completes the seek operation in a short time. , or 2. Reliability can be improved.

FIG. 2 is an example (servo pattern) of discrete servo sectors embedded in advance in the information track on the rotatable recording medium 1 in one embodiment of the present invention shown in FIG. 3 is a data sector. This servo sector 2 is provided with a burst section 18 for obtaining It and AGC signals, an erase section 19 for detecting the servo sector, and a track code section 20 for obtaining track address information. . The erase section 19 is set to have the maximum erasing time in the information track of the recording medium 1.鑞 Writing to this servo sector is prohibited.

Now, in the track code section 20, (a sync bit S indicating the start of the front track code section 20, a zone discriminating section 2 consisting of three dibit patterns A, &C1 for discriminating the guard zone, data zone, and type of data zone).
0a, 3) 3-phase dibit pattern G, H with rack period.

(1) A first servo pattern 20b consisting of 20b, and a second servo pattern 2 consisting of two quick bit patterns D and E with a period of 12 tracks and a deviation of 3 tracks.
Even if a third servo pattern 20d consisting of a dibit pattern F with a period of 0c, 6 tracks and a deviation of at least 1.5 tracks from the second servo pattern is embedded, here, in FIG. The second servo pattern 20c and the third servo pattern 20d, which are composed of two dibit patterns, are the first servo pattern 2.
A second servo pattern consisting of two Guibit patterns may be placed on both sides of the first servo pattern.
Place the second servo pattern on one side of the first servo pattern.
A third servo pattern may be arranged on the other side of the first servo pattern, and each of the second servo pattern and the third servo pattern is arranged on the first servo pattern consisting of three dibit patterns. The data head 5 may be arranged alternately with the pattern (-and when performing a recording/reproducing operation on a data track, the data head 5 travels across two adjacent tracks with respect to the servo sector 2).

Assuming that the data head 5 is now at the sixth track position on the recording medium, the waveform reproduced by the data head 5 will be as shown in FIG. Strap plate Burst part 1
8, a predetermined reference signal; no signal in the erase section; and, in the track code section 20, at the sync bit position S, at zone discrimination positions 9 B and C,
At the second servo pattern position E, at the third servo pattern position F, at the first servo pattern position G,
At H and I, signals corresponding to each servo pattern are obtained.

In Figure 3, the positions are S, B, C, E, F,
At G and I, we get a playback signal with output 1 and position, and at H we get a playback signal with output 0. It goes without saying that this playback signal changes depending on the track position of the data head 5 on the recording medium. In the present invention: The track position of the data head 5 relative to the recording medium is detected with high precision in the following manner according to the first to third servo patterns 20b, 20c, and 20d obtained in the following manner, and a seek operation is performed to the selected target track. head positioning.

FIG. 4 shows the ideal output state transition of the reproduced waveform when the data head 5 moves the servo sector as shown in FIG. 2 at low speed from the inner circumference to the outer circumference of the recording medium. The slope of each reproduced signal in the figure is determined by the output value according to the ratio of the dibit pattern to the head width when the data head 5 has a finite width when the head crosses each dibit pattern.

In addition, the numbers from OO to 11 in FIG. 4 correspond to the track numbers of the 12-track period shown in FIG. It shows.

Here, the reproduced signals E and F obtained from the second and third servo patterns are binarized at a preset level, and the reproduced signals G, H, obtained from the first servo pattern are After peak-holding each playback output, r compares each value and converts it into binary information.
Playback signal RI, E, F, G, Hl ■ The above two 2
Let the digitized information be the first binarized information, and then perform the above G, )L according to the value of the first binarized information.
The internal I signal also adds a preset offset to the signal that holds a low value, and compares it with the corresponding signal again to obtain the second binary information. The position of the data head 5 on the servo track is set to 1/(2) of the track width using the converted information and the second binarized information.
First, the second servo pattern D, Ef& has a cycle of 12 tracks each, and a deviation of 6 tracks is set on the holding plate.The 3 tracks overlap each other, and the D signal and E signal are obtained from the playback output. Therefore, if the reproduced signal is ideal, D
It is possible to limit 3 of the 12 tracks using only the signal and the reproduction output of EJI'ii. However, there is a finite width in the middle plate head, and the playback output does not change digitally. It is difficult to limit the tracks.Therefore, a third servo pattern F is provided which has a cycle of 6 tracks and has a mutual overlap of 1.5 tracks with the D pattern or E pattern. At the slope portion of the FζiD signal or the E signal, it always becomes the "L II level" or the "H" level.

(Left below) Table 1 shows the binarized information of the D signal, uE signal, and F signal for each servo track in a servo sector with a cycle of 12 tracks. *This is an area where it is unclear whether the binary output will be at the ``L'' level or the ``H'' level depending on the position of the data head when detecting the mark G & signal. When the level of either E is indeterminate, the level of signal F is '
It is configured such that it is determined to be "L" or "HD."

Therefore, by detecting the levels of the signals 1, L, and F, it is possible to determine in which three of the 12 tracks the data head 5 is located.

Next, the reproduced signal G obtained from the first servo pattern,
Based on H and I, determine where the data head 5 is located within the limited three tracks.4 Fifth
The figure shows the ideal reproduction output of signals G, H1, and signal I when the data head 5 moves the servo sector as shown in FIG. 2 at low speed from the inner circumference to the outer circumference of the recording medium. Figure 5 shows an enlarged view of the five data heads (moving from servo track C to g), and signals G, Hl
Even if ■ is shown overlapping the signal G, H1■
Even if the peak value of the output is normalized (maximum is 1), the binary detection code of signal RI, E, and F is now ++ H″′″I ) I II II n, l
'', as can be understood from Table 1, the data head is located somewhere between tracks d, e, and f within the servo sector.
The peak value of the reproduced signal from 1■ is 22, 23, and 24, respectively, as shown in Fig. 5, then the value of the G signal>
It can be seen that the signal value multiplied by tH of the H signal is the enemy of the G signal.

In other words, when comparing &G signal value > tH times signal value of H signal > ■ iI times signal value of signal > G signal value,
The answer is 'H'''H''''II L +1 From this answer, it can be determined that the magnitude of each peak value is larger in the order of G, H, and I.Result From Figure 5 Data head position C
Since the L G signal is the largest, d, e
, e-track number of the 3 tracks of f
Value of H signal> ■ From the signal value, it is determined that the signal is located in the area e2 (shown in FIG. 5).

E signal uF signal G signal uH signal ■Each signal is ``H'''
“H”” “L II )l H1” ’H”, ’L
''), G, Hl ■ Signal internalization also adds an offset to the engineering signal with a low peak value First offset value ζi The maximum peak value of G, H, I is set to 1
When normalized to 0.5, it is equivalent to 0.5. ■0.5 for signal
After adding the offset, the peak value of the signal ζ moves from position 24 to position 25 in Figure 5. Then, when we again compare [H signal value> ■ Signal cage, the answer is L "L" means &H times the signal value> Comparison of the signal value (after adding an offset of 0°5) (useful for determining the more detailed position of the data head. In other words, the H signal value〉■ Signal value (0,5
), the answer is ′
The peak value of the H signal is 0.5 or more greater than the peak value of the engineering signal.If the answer is 1.11, the difference between the peak value of the H signal and the peak value of the I signal is 0.
．． This means that it is possible to determine whether the position of the data head (above) is the first half (e03) or the second half (e04) of the area e2 above.Result H
Is the difference between the peak value of the signal and the peak value of the engineering signal smaller than 0.5? In this way, you can determine what
The second binary information makes it possible to determine in detail the relative positional relationship of the data head to the track in the servo sector down to 1/(2N) of the track width.

Rough ■Add an offset of -0.25 to the signal,
H signal value> ■ Compare the signal value (after adding an offset of 0, 5 - 0, 25) (\ Create the third binary information) ζL Relative to the track in the servo sector of the data head Positional force (1/(2N) of track width
) in accordance with the Nth binarized information.
By adding the offset given by the uH signal or the signal (2), it becomes possible to determine the relative positional relationship of the data head to the track in detail down to 1/(2N) of the track width. Above G signal u H48% of 3 track period in servo sector Value of G signal present in I signal > tH times signal value of H signal > ■ Signal's enemy ■ Signal value > G signal's enemy
Table 2 summarizes the first binarized information of (a~1), (al, a2~]1.
The alphabets up to 12) are the same as those shown in FIG.鑞 Binarized information is ′″H′″”H″′″H′
'', or II Lll"L""'L"', so it does not exist in the table (t For example, if the data head is located at the position shown in Figure 5, G>H , H>I, I>G answer is II H″″II
According to Table 1, if the data head is located somewhere between tracks d, e, and f in the servo sector, then from Table 2, the data head is located at e.
The ability to create the second binarized information in order to determine in detail up to 1/4 of the track width (which signal to which an offset is added is shown in the table below). G of the first binary information signal as shown in 3.
>H, H>■, I>G is n H″l n Hll n
If it is L'', then the signal G, H, I is G, H,
The peak value becomes larger in the order of I, and adding the offset (0, 5) results in a signal of ζ. Using Table 3, the answer of G>HlH>I, I>G is “$ II
# In the case of E("IIL, II"), the name of the signal to which the first offset is added is engineering signal, which matches the above result.Therefore, using Table 3, the first offset can be Determines the signal name to be added.

Table 4 shows the results of region discrimination based on the second binarized information. In addition, $ mark ζmelon Signal area with added offset 4, it is determined that the data head is located in the e03 area. To determine the position of the data head up to 1/(2N) of the track width, use ζ. The answer to the second binarized information is " H” power＼L
''Depending on the power, the second offset of 0.25 is added to the signal with the first offset added.
; You can either subtract 0.25 or add 0.25 to the other side compared to create the second binarized information. After adding the offset, set G>HlH>I again.
, By comparing I>G, the second binarized information is obtained, and it is possible to determine the position of the data head up to 1/(2N) of the track width (see the margin below). The analogy for region discrimination based on binarized information is that in the case of the above example, after subtracting 0.25 from the peak value of the I signal to which 0 and 5 have been added, the power of comparing H〉■ again is\
0.25 is added to the H signal and the comparison of H>I is performed again. If the answer is <, H'', then the second half of the e03 area!
If L'', it is determined that the data head is located in the first half of the e03 area, which is 1/(2N) of the track width.
It becomes possible to determine the position of the data head up to

In any case, the one that shows the lowest peak value of the reproduced signals G, Hl 1/(2) of the maximum value of the reproduced signal
Adding the offset of N), G>H, H>I, I>
Proceeding with the comparison of G, the track width l/(21'l
), it is possible to determine the position of the data head.

FIG. 6 shows head position information recognition means 10 and servo information demodulator 8 of a head positioning device in an embodiment of the present invention.
A is a block diagram explaining in more detail the signal detected from the recording medium by the data head 5, which is amplified by the preamplifier 7, and then is sent to an AG that normalizes the output value using the burst section 18 etc. embedded in the servo sector 2.
Servo information demodulator 181LAG also transmitted to C amplifier
A binarization circuit 3 that binarizes the signal standardized by the C amplifier 38 and the AGC amplifier 38 at a predetermined threshold value.
9, an erase part detector 40 which finds the erase part 19 with the longest interval from the continuous binary signal, and starts a counter at the same time as detecting the erase part 19, and forms it embedded in the servo sector 2. The head position information may be composed of a sector counter and a gate generator 41, which generate a gate for detecting the signal A-I of a certain track code 20, and a gate for discriminating the data sector 3 and the next servo sector. The recognition means 10 receives a gate command from the sector counter and gate generator 41, and temporarily converts the binarized information of the signals A, &α D, B, and F out of the signals binarized by the binarization circuit 39. The signals G and Hl of the signals received from the memory circuit 36 to be stored and the gate commands from the sector counter and gate generator 41 and standardized by the AGC amplifier 38 are
■A peak holder G26 that holds each of the peak values;
A peak holder H27 and a peak holder I28,
A comparator 29 that compares the peak value of the peak holder G and the peak value of the peak holder H, and a comparator 3 that compares the peak value of the peak holder H and the peak value of the peak holder ■.
0, the peak value of peak holder I and peak holder G
A comparator 31 that compares the peak values of , and comparators 29 and 30
, 31, and together with the binarized information in the storage circuit 36 constitute the first binarized information.
2 and the peak holder G depending on the contents of the first latch 32.
, Hl (2) to which the first offset is to be added in accordance with the decoding method shown in Table 3;
Offset adder 34 to add to any one of Hl ■
a second latch 35 that holds the comparison result between the peak holder to which an offset has been added by the offset adder 34 and the corresponding peak holder to form second binary information; The relative positional relationship of the data head to the servo track is determined using the first binary information formed by the contents of the first latch 32 and the second binary information formed by the second latch 35. and a head position information discriminating element 37 for discriminating.

With the configuration described above, the head position information recognizing means 10 can determine the relative positional relationship of the data head to the servo track in detail down to 1/(22) of the track width.

Therefore, during track access control, the moving speed of the data head can be recognized with a resolution four times higher than conventional methods, making highly accurate speed control possible.

Hammer head position information discrimination element 37 (above Tables 1 and 2)
, Table 3 and Table 4 are used to determine the position of the data head in the ROM.
You can also use hardware such as a table.
Alternatively, it may be performed by software using a central processing unit (CPU) or the like.

FIG. 7 shows a block diagram in which the head position information recognition means shown in FIG. 6 is configured so that the relative positional relationship of the data track to the servo track can be determined in detail down to 1/(2N) of the track width. It is a diagram. Map East No. 6
Blocks with the same numbers as in the figure have the same functions as the blocks in FIG. In FIG. 7, a head position information determining element 37 selects a peak holder to which an offset is to be added based on the first binarized information formed by a storage circuit 36 and a first latch 32, and selects a peak holder to which an offset is to be added. The first offset value to be calculated is commanded to the offset adder, and the peak holder to which the offset value has been added is compared with the corresponding peak holder.
Furthermore, according to the result of the second binarized information, the offset adder is instructed to select the peak holder to which the second offset is to be added and the second offset value to be added. Compare the peak holder with the added value and the corresponding peak holder. As a result, the relative positional relationship of the data head to the servo track can be determined in detail down to 1/(2N) of the track width by using the binarized information from the first latch to the Nth latch. Results During track access control, the moving speed of the No. 2 data head can be recognized with a resolution 20 times higher than conventional methods, making highly accurate speed control possible.

Song It is also possible to configure the head position information determination element 37ζ only with hardware such as a ROM table.It is better to configure it using hardware such as a central processing unit (CPU) and software. Figure 8 shows N=7 and L using the above head position information recognition means.
A head positioning signal generation device (generating a position signal with a cycle of 12 tracks) is composed of a head position information recognition means configured to detect up to the seventh binary information and a central processing means (CPU). The target track ζ is generated so that it is always positioned at the center of the position signal of 12 track cycles, and the relative positional relationship between the data head and the track can be recognized with a resolution of 1/(27) of the information track width. In FIG.
Head position can be detected with a resolution of /(2N) 1
A track can be represented by an area code from 0 to 127. Therefore, 12) The position signal extended to the rack is 0.
Although it is possible to represent the area code -1537, the number 0 to 127 j indicates the area where the head is located.
Friend 26 more a01 to 104 in Table 4
The head position detection resolution during tracking control is equivalent to the divided area: 1/(27) of the information track width
If higher head position detection resolution is required (N = 8 for head position information recognition means)
It is sufficient to select a configuration that can realize the above. Figure 9 shows the head positioning generation device force (the relative positional relationship between the data head and the track is 1/(2N) of the information track width).
A method of generating the extended position signal shown in FIG. 8 using a central processing unit (CPU) and a head position information recognition means that recognizes the head position information with a resolution of . Now, if the cylinder number of the target track is 81, 1 of the information track width
Target track 4181/12=6 with a resolution of /(2N)
The remainder is 9, so the remainder is 9, so 9*128=1152
According to the area code, position 1152 is the target track position.If the cylinder number where the head is currently located is 10, then the distance to the target track (1/(2N) of the information track width) ) When calculated using the resolution, it becomes (81-10) * 128 = 9088. Area code 4 of cylinder number 10; t, .
10/12=0 remainder 10 or 6 10*128=1
280. When a seek operation is started from cylinder number 10 to cylinder number 81, each time the data head passes through a servo sector, the data head determines the position (area code) at a resolution of 1/(2N) of the information track width. The moving distance and speed calculated from the position passed one sample time ago can be detected.

In other words, when the above seek operation starts and the first servo sector is passed.Assuming that 1472 can be detected with a resolution (area code) of 1/(27) of the information track width, the data head will detect the area code from 1472-1280-192. This means that we have advanced by 192. Therefore, the remaining table area code is 9088-192=8896.
Then, if the data head detects area code 192 when passing the next servo sector, the moving distance from the previous servo sector sample is 1; 11536-1472.
+192=g56, and the remaining distance to the target track is 8896-256=8640.

Here, when calculating the moving distance, if the area code where the data head is currently located is a small value and the area code where the data head was located one sample ago is a large value, use the above example. Travel distance -1536-(
It is clear that the moving distance is calculated by (region code of one sample before) + (current region code). By continuing the seek operation as described above, the remaining distance to the target track decreases, and the remaining distance or area code is 768 (6 rack * 128 area - 768 area)
The head positioning signal generation device generates an extended position signal at the point when the position is reached. As shown in FIG. 8, when the remaining distance to target cylinder number 81 (area code 1152) reaches 768 in area code, if the area code from the detected servo sector is 512, then Using the flow shown in , PES (position error amount up to the target track) with the expanded position signal - 1660 and the center of the target track (area code of the target cylinder 1152) and the center of the expanded position signal ( 0
level position).

8. As a control signal used in the control system, the expanded position signal necessarily has positive or negative polarity before and after the target track1. Therefore, the data head approaches the target track from the outer or inner circumference side. , the extended position signal always has a large positive or negative value (-7e8
<PES≦768), it approaches 0.

Next, if the area code length obtained from the passed servo sector is 768, the position error with respect to the target track in the expanded position signal of the data head will be PE5--384 according to the flow of FIG. Position error to the target track PE5 = -128 range (Urban: Within 1 track of the target track, PE5 = 0
Needless to say, it is necessary to finely control the data head to follow the center of the information track so that 1 or
If the data head approaches the target track shown in Figure 8 from the opposite direction to the above direction (the extended position signal approaches the target track with a large positive value (768 or less). Assuming that area code 256 is detected when passing through a certain servo sector, using the flow shown in Figure 9, the positional error PE5 of the lL data head with respect to the target track becomes +640, which means that the above rule is satisfied. Edge Even in this case, it goes without saying that the data head is controlled to finely follow the center of the information track so that the position error PE5 to the target track is 0.

The following describes the method of generating and using the position signal extended to 1.12 tracks.Furthermore, using FIG. Explain the functions. In the seek operation, when the target cylinder number is manually input to the control system, the command speed is output from the speed command device 11 which commands the target speed according to the distance to the target track or the number of tracks to the target track, and the command speed is output from the speed detector 12. By feeding the error back to the VCM positioner 6, the data head starts moving toward the target track. Every time the head positioning signal generator 100 passes through a servo sector, the head position information recognition means 10 detects the position (area code) at a resolution of 1/(2?) of the information track width. The moving distance is calculated from the area code). The head positioning signal graphic device 100 subtracts the moving distance for each sampling from the previously calculated moving distance ((cylinder number of target track - cylinder number of current track) * 128). Then, when the remaining distance becomes 768 or less in terms of the number of area codes, the head positioning signal generation device 100 starts generating an extended position signal of 12 track periods. The timing to switch from speed control to follow-up control should be approximately 2 to 3 tracks before the target track due to short-time seek conditions such as avoiding a long establishment time after switching to follow-up control and entering the target track as fast as possible4. . In the head positioning signal generation device 100, the extended position signal is generated from 6 tracks before the target track.\ The data head moves by speed control until 2 to 3 tracks before the target track. Two or three tracks before, the switch 16 is switched to the follow-up control side. Thereafter, the data head establishes the center of the target track according to the extended position signal PES (position error signal) which sets the center of the target track to 0 level.

FIG. 10 is a diagram showing the difference in entry speed and entry position between the conventional method and the method of the present invention, and the establishing time. The position signal in FIG. 10 shows established characteristics when the position of the data head is detected with a resolution of 1/(27) of the information track width. Also, the sampling frequency of the servo sector is set sufficiently high. Figure 10(a) shows the case where the dynamic range of the position signal is about ±1/2 track, and shows the trajectory of the data head when switching from speed control to follow-up control about 1/2 track before the target track. Also, the entry speed is 1.25cm/s, 2
．． Force <, assuming three cases of 5cm/s and 5crn/s 1. In the case of 25cm/s and 2.5cm/S, although there is an overshoot, the target track is established, but the target track is only slightly settled.At an entry speed of 5cm/s, the entry speed is too fast and cannot be established within the dynamic range of the position signal. However, a seek error is occurring. On the other hand, the 10th
Figure (b) shows the case where the dynamic range of the position signal is about ±6 tracks, and even if it shows the trajectory of the data head when switching from speed control to follow-up control about 3 tracks before the target track, the entry speed is 50 m. /s, 1
0 am/s, , 15 cm/s force <, 5 cm/s, slightly undershoot, 15
cm/s is a force with a slight overshoot (established on the target track.Especially at an entry speed of 10 cm/s, it shows a good establishment state for a short time.As described above, an extended position signal is generated. By doing this, it is possible to make the head enter the target track faster and in a shorter time.And even if the entry speed is significantly deviated from the temporarily set entry speed, the extended position signal with a wide dynamic range can be used. By using , it is possible to improve reliability.

Effects of the Invention Head positioning signal generation method and device of the present invention and head positioning device ζ
It is concerned with methods and devices for generating head positioning signals at the time of transition to seek control and tracking control, and head positioning devices using the above devices, and is mainly concerned with head positioning signal generation methods and devices that use the above-mentioned devices. Form at least two small servo patterns with M track periods (M is an integer of 2 or more), and 2 small servo patterns detected from the above servo patterns.
A head position information recognition means that finely detects the relative positional relationship of the data head to the track down to 1/(2N) of the track width using only digitized information, and a central processing unit (
(CPU) is used to generate an extended position signal with a cycle of M tracks and a dynamic range of M tracks, and by using the extended position signal when entering the target track, the seek operation is made faster and shorter, and Therefore, by embedding servo sectors as shown in the present invention on the data surface and configuring a head positioning device using the head position information recognition means, high precision can be achieved. By relying on accurate head position recognition, the moving speed (seek speed) of the data head can be detected with higher resolution, making stable and high-band speed control possible even at low speeds. In addition,
The head positioning signal generation device has a cycle of M tracks and M
It is possible to generate a position signal with an extended dynamic range of the track.It is possible to make the data head enter the target track at high speed and with high reliability even in the transient state when switching from speed control to tracking control.4 Atsushi Sota This prevents overshoot or undershoot of the data head when transitioning to follow-up control operation.

In addition, it has the effect of reducing the probability of seek errors such as overrunning a track or backtracking, and improving the reliability of seek operations.

Air Supply The present invention is a disk device configured with discrete servo information, which can provide high speed and reliability equivalent to or higher than conventional disk devices configured with continuous servo information.

Furthermore, by embedding the servo pattern on the data surface, which is the positioning method of the present invention, it is possible to increase the number of information tracks as recording density increases, compared to the conventional method of encoding track numbers. However, there is an advantage that a small servo area is sufficient. In other words, since the ratio of the servo area to the data area on the recording medium does not change, it has the advantage of making it easy to secure a large capacity without changing the design even when recording density increases.

[Brief explanation of the drawing]

FIG. 1 shows a basic block diagram of a head positioning device in an embodiment of the present invention. Figure 3 shows a pattern diagram of a specific example of a discrete servo sector. Figure 4 shows a reproduced waveform diagram when a data head crosses a servo sector as shown in Figure 2. Figure 5 shows the ideal reproduction state when the data head moves the servo sector as shown in Figure 2 at a low speed from the inner circumference of the recording medium toward the outer circumference of the recording medium. The reproduction output state shown in FIG. FIG. 7 shows the information demodulator and the head position information recognition means in more detail. The head position information recognition means shown in FIG. When the block diagram is configured to enable detailed discrimination, the block diagram shown in Figure 8 is an expanded position signal diagram with a period of 12 tracks. A flowchart showing a method for generating the extended position signal shown in FIG. 8 using head position information recognition means and a central processing unit (CPU) that recognize the head position information with a resolution of 1/(2N) of the width. This is a diagram showing the difference in performance capability using entry speed and entry position as parameters when the dynamic range of the signal is about ±1/2 track and when it is ±6 track.41... Rotatable recording medium 2...Servo safety 3...Data safety 4...Information track 5...Data head, 6...VCM positioner, 8...Servo information demodulation edge 1O...Head position information recognition means, 11...
・Speed command device 12...Speed detector 17...Current driver 18--Burst K 19...Erase 120--Track code 22-Peak halt of reproduction signal G 23...Reproduction signal H Peakholt's enemy 24... Beakholt's enemy of playback signal ■ 25...
・Peak holders after adding an offset of 0.5 to the reproduced signal ■ 26, 27, 28...Peak holders, 29
, 30, 31... Comparison 凰 32... First latch,
33...Offset decoder, 34...Offset addition hemp 35...Second latch, 37...Head position information discrimination requirement 39...Binarization circuit 40...Erase section detector 41. ... Sector counter and gate generation hemp 100 ... Head positioning signal generation device 10
1...Central processing unit (CPU). Ward Φ Work chart chart chart chart f6・-Or・C

Claims (3)

[Claims] (1) A servo pattern is formed discretely in the circumferential direction of a rotatable recording medium, and the servo pattern is composed of at least two small servo patterns of M track periods (M is an integer of 2 or more), and each servo pattern is The peak values of the reproduced signal amplitudes of the patterns are compared and set as first binary information, and then at least one of the peak values of the reproduced signal amplitudes is set to 1 according to the value of the first binary information. After adding the second offset, the respective peak values are compared again to create second binarized information, and then the peak value to which the offset has been added is further added according to the value of the second binarized information. Add a second offset to the peak value when creating the second binarized information, or add a different offset from the first time to the peak value to which no offset was added when creating the second binarized information and compare each again. By creating the third binarized information and continuing the above operation up to at least the Nth (N is an integer), the position of the head in the radial direction of the recording medium can be finely adjusted to 1/(2^N) of the track width. The distance between the arbitrarily determined track and the head in the radial direction of the recording medium is calculated with a resolution of 1/(2^N) of the track width, and the period is M tracks according to the above calculated value. A head positioning signal generation method characterized by generating a head positioning signal having a dynamic range of . (2) A servo pattern is formed discretely in the circumferential direction of a rotatable recording medium, and the servo pattern is composed of at least two small servo patterns having an M track period (M is an integer of 2 or more), and the small servo pattern is at least two peak holder elements each storing the peak value of the reproduced signal amplitude of each pattern, at least one comparison element comparing the at least two peak values, and a first peak holder element storing the output of the comparison element. a first latch element that holds binarized information; an offset decoder element that determines which peak holder element to apply an offset to according to the contents of the first latch element; The offset addition element that adds an offset to the peak holder element of , and the peak holder element to which the offset is added and the peak holder element to which no offset is added are again compared using the above comparison element, and the results are temporarily stored and the second A second latch element that holds the binarized information, N latch elements that latch the binarized information up to the Nth, and the contents of the first latch element to the Nth latch element are used. head position information recognition means comprising a head position information discriminating element for detecting the relative positional relationship of the data head to the track up to 1/(2^N) of the information track width; The distance in the radial direction of the recording medium between the track and the data head is calculated with a resolution of 1/(2^N) of the track width, and according to the calculation result, a head positioning signal with a cycle of M tracks and a dynamic range of M tracks is generated. 1. A head positioning signal generation device comprising a central processing unit (CPU) that generates a head positioning signal. (3) a discrete servo pattern formed in the circumferential direction of a rotatable recording medium, a data head capable of reproducing at least the information on the recording medium, and a reproduction signal of the data head to the discrete servo pattern; A servo information demodulating means for extracting the included servo information and a relative positional relationship between the data head and the track are set to 1 of the information track width.
M
A head positioning signal generating device according to claim 2, configured to generate a head positioning signal having a cycle of tracks and a dynamic range of M tracks, and an output of the head positioning signal generating device according to a distance to a target track. speed command means for outputting a track access speed command based on the speed of the recording medium; speed recognition means for determining the moving speed of the data head in the radial direction of the recording medium; and positioner means for moving the data head to an arbitrary position in the radial direction of the recording medium. The track following control is configured by feeding back at least a signal based on the output of the head positioning signal generation device to the positioner means, and the track access control is configured by feeding back a signal based on the speed error between the speed command means and the speed recognition means. A head positioning device characterized in that it is configured by returning to a positioner means.