JPH04111269A - Velocity controller for data recording and reproducing device - Google Patents

Abstract

PURPOSE:To quickly and accurately move a head to a target position by using an address code representing a cylinder number at every sector, and burst data recorded at a position deviated from the center position of a track by half track. CONSTITUTION:The address code Cn and the burst data A, B are recorded on a disk 10 at every sector. They are detected by an address code detection circuit 14 and a burst data detection circuit 15 while the head travels advancing the target position XR of the head 11, and a CPU 17 controls the travel speed of the head 11 by calculating target speed in accordance with residual distance from the present location to the target position by using position information consisting of a value equivalent to the integer part of the position information representing the present location of the head calculated based on the address code, and a value equivalent to the decimal part of the position information calculated based on each level of the burst data A, B. Thereby, it is possible to accurately detect the present location, and to quickly and accurately move the head to the target position.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention (Field of Industrial Application) The present invention relates to a speed control device used in a data recording/reproducing device such as a magnetic disk drive (HDD).

(Prior Art) Conventionally, for example, in a sector servo type magnetic disk device, a position signal is created based on servo data recorded on a disk in advance, and head positioning control is performed based on this position signal.

This head positioning control can be roughly divided into a speed control mode and a position control mode. In speed control mode, the head movement speed is detected based on the created position signal,
Speed control is performed to correct the error between the detected speed V and the target speed VR. In the position control mode, when the head moves to the target position XR, that is, the target cylinder (track) in the speed control mode, position control is performed to correct the error between the current position Xn of the head based on the position signal and the center of the target position XR. Action is performed.

By the way, the target speed VR of the head is determined according to the remaining distance XE from the current position Xn of the head to the target position XR, and its value is set in advance in a speed table as shown in FIG. ing. Therefore, in the speed control mode, by referring to this speed table, it is possible to obtain the target speed VR corresponding to the remaining distance XE.

Here, in a conventional magnetic disk device, as shown in FIG. 10, no matter where the head 11 is located from P1 to P3, if the head 11 is on the same cylinder (track), the current position Xn of the head 11 can be determined. The values shown are the same. For this reason, it is not possible to obtain an accurate target speed VR corresponding to the remaining distance XE, and as shown in FIG. 9, there is a problem in that the error between the target speed VR and the detected speed ■ varies greatly.

In such a case, the next position control becomes difficult, resulting in a long seek time.

Note that in order to accurately detect the position of the head 11, some devices employ a position detector such as a linear sensor, but in this case, there is a problem that the device becomes complicated and costs increase.

(Problems to be Solved by the Invention) As described above, conventionally, it has not been possible to accurately detect the head position. For this reason, there are problems such as a large error variation between the target speed and the detected speed, and a long seek time.

The present invention was made in view of the above points, and an object of the present invention is to provide a speed control device for a data recording/reproducing device that can accurately detect the head position and quickly and accurately move the head to a target position. shall be.

[Structure of the Invention] (Means and Effects for Solving the Problems) A speed control device for a data recording/reproducing device according to the present invention has an address code indicating a cylinder number for each sector, and A value corresponding to an integer part of position information indicating the current position of the head calculated based on the address code, comprising a recording medium having burst data A and B recorded at a position shifted by half a track;
Then, using position information consisting of a value corresponding to the decimal part of the position information calculated based on each level of the burst data A and B, the remaining distance from the current position of the head to the target position and this distance are determined. The moving speed of the head is controlled by calculating a target speed according to the remaining distance.

According to such a configuration, by using the address code and the burst data A and B, the current position of the head can be detected as a positive real number including a decimal value. Therefore, by reducing the error fluctuation between the target speed and the detected speed,
The head can be quickly and accurately moved to the target position.

(Embodiment) Hereinafter, a speed control device for a data recording/reproducing apparatus according to an embodiment of the present invention will be described with reference to the drawings.

Figure 1 shows, for example, a sector servo type magnetic disk device (
1 is a block diagram showing the configuration of a speed control device used in a HDD. In FIG. 1, a head 11 moves over a disk 10, which is a recording medium, and records/reproduces data.Here, a read signal (analog signal) a is sent to a read circuit 12 and a burst data detection circuit. 1
Output to 5.

As shown in FIG. 2, servo information consisting of an address code Cn and burst data A and B is previously recorded on the disk 10 for each sector. Address code Cn is information indicating a cylinder number. Burst data A and B are recorded offset by half a track from each other with respect to the center position of the track.

The read circuit 12 binarizes the read signal a and outputs the read pulse b to the erase detection circuit 13 and address code detection circuit 14. The erase detection circuit 13 is
It detects the erase area (see Figure 2) indicating the start of a sector, and by inputting read pulse b, the erase state (no signal state due to direct current erasure, for example, "O" level) is detected. It is detected that the signals are recorded continuously for a predetermined period of time or more, and the signals c, d, and e are outputted according to the detection timing.

The address code detection circuit 14 is the erase detection circuit 13.
Serial/parallel conversion is performed on the read pulse b at the timing of the signal C from , and the address code Cn in the read pulse b is output to the CPU 17 .

The burst data detection circuit 15 is connected to the erase detection circuit 13.
The burst data A and B in the read signal a are sampled and held at the timing of the signal d from , and the A/D converted values of the respective levels An and Bn of the burst data A and B are output to the CPU 17. In the speed table 16, a target speed V corresponding to the remaining distance XE to the target position XR is stored in advance.
R is memorized. In this embodiment, as shown in FIG. 6, the remaining distance XE stored in the speed table 16 is set as a real number including decimals such as 0, 0.25, 0.75, etc. has been done.

The CPU 17 is in charge of controlling the entire device, and here the control data of the voice coil motor (hereinafter referred to as VCM) 19 is transmitted by executing speed control processing as shown in the flowchart of FIG. It calculates and outputs it to the VCM driver 18. VCM driver 18
drives the VCM 19 under the control of the CPU 17.

VCM 19 is a motor for driving head II.

Next, the operation of this embodiment will be explained.

First, when the target position XR is determined, the head 11 moves in the radial direction of the disk 10 toward this target position XR, and reads the servo information recorded on the disk 10 during the movement. This servo information is address code Cn
and burst data A and B. Address code Cn is detected by address code detection circuit 14 and given to CPU 17. Burst data A
,B each level An.

Bn is detected by the burst data detection circuit 15 and provided to the CPU 17. As a result, CPU1
7 is address code C and burst data A, B.
The current position X of the head 11 is determined using the levels An and Bn of
n is detected, and speed control as shown in the flowchart of FIG. 3 is executed.

That is, the CPU 17 first calculates a value Xna corresponding to the integer part of the position information indicating the current position Xn of the head 11 based on the address code Cn (step Sl
). Next, the CPU 17 calculates a value Xnb corresponding to the decimal part of the position information as follows based on the burst levels An and Bn (steps 82 to S4).

When the integer value Xna is an odd number, Xnb= (An − Yb ) /Ya − (1)
When the integer value Xna is an even number, Xnb = (Bn - Yb) / Ya - (2
) In equations (1) and (2), Ya and Yb are the fourth
These are the slopes and Y-intercepts of the burst levels An and Bn shown in the figure.

In this way, the CPU 17 determines the current position
When we obtain Xn = Xna + Xnb - (3) as n (step S5), the position X n-1 at the time of n-1
The moving speed V of the head 11 is detected from the sector interval time t and the sector interval time t as follows (step S7). In addition, n
indicates the sample number when obtaining position information.

V-(Xn-Xn-1)/t-(4)
Here, assuming that the reference speed when transitioning from the speed control mode to the position control mode is VZ, if V>Vz (step S7), the CPU 13 calculates the remaining distance XE from the current position Xn to the target position XR. Then, by outputting a value In obtained by multiplying the error between the target speed VR and the detected speed V (actual moving speed of the head 11) by a gain K to the VCM driver 18 according to the distance XE, the moving speed of the head 11 is determined. (steps 88-512).

Specifically, CPU17 moves from the current position Xn to the target position
The remaining distance XE to R is calculated as follows (step S9).

XE −XR+0.5−Xn ・−(5) Furthermore,
In equation (5), 0.5 corresponds to the distance from the end of the track to the center position when the track width is 1. Next, the CPU 17 refers to the speed table 16 shown in FIG. 6 and asks if the target speed Vl is appropriate for the remaining distance X? (Step 510) Then, the CPU 13 calculates the VCM1 based on the error between the target speed VR and the detected speed V.
9 is calculated as follows, and this is output to the VCM driver j8 (step Sll,
512).

I n-K (VR-V) - (6) If V≦VZ in step S7, the current value rn is calculated by a position control routine (not shown) in step 31B.
), this is output to the VCM) driver 15 (step 512). Note that this position control routine is not directly related to the present invention, so a description thereof will be omitted.

Next, for ease of understanding, the steps 81 to S5 described above are explained below.
The processing up to this point, that is, the position detection and speed detection processing of the head 11 using the address code Cn and burst data A and B will be explained using specific numerical values.

For example, when the head II is located at the cylinder (track) 13 shown in FIG. 2 at the time of n-11,
The address code C is detected by the address code detection circuit 14.
13 is detected and its code C13 is given to the CPU 17. As a result, X1la-13 is obtained as the integer value Xlla of the current position Xn of the head 11.

On the other hand, the peak values of burst data A and B are sampled and held by the burst data detection circuit 15, and the level A11. B 11 is given to the CPU 17. Here, as shown in FIG. 4, the burst level All
The value of 2', 6. Assuming that the value of Bll is 3.4, the value of the slope Ya of the burst level is 4, and the value of Yb is 1, the integer value X lla is an odd number, so the decimal value of the current position As Xllb, XLlb-(2,6-1)/4-〇,4 is obtained. As a result, the position Xll of the head 11 at n-11 becomes Xll - Xlla + X11b -13+0.4 -13.4 according to equation (3).

Similarly, when n-12, for example, burst level A12
-1.4, B 12-4 , if 6, then X12a
-CI2 =16 (even number) X12b -(4,6-1) /4-屹9 X12 -16+0. 9 -16.9. Also, when n-13, for example, if the burst level is Al3-3.0 and BI3-3.0, then X13a
-C13 -19 (odd number) X13b -(3,0-1) /4 -屹5 X13 -19+0.5 -19.5.

Here, if the sector interval time t is set to 1, the detected speed V12 at the second point is expressed as V12-X by equation (4).
12-X 11 -16.9-13.4 -3. 5 [track/sector]. Similarly, the detected speed V13 at the third point is V J3- X 13- X 12 -19. 5-16. 9-2. 6 [) It becomes rack/safetaco.

In this way, by using the address code Cn and the burst data A and B, the current position Xn of the head 11 is
O values can be detected accurately as real numbers including decimal values. Therefore, the remaining distance XE from the current position Xn to the target position XR, and the target speed V corresponding to the remaining distance XE.
The value of R can be calculated accurately, thereby reducing error fluctuations between the target speed VR and the detected speed (2), and shortening the seek time.

Note that by configuring the address code Cn with a Gray code or the like, it is possible to prevent the value of Xna after conversion from changing to a value other than that of an adjacent track. Also, generally between tracks, there is an
There are areas where it is uncertain which track the naO value will be, but even if it changes to the value of the adjacent track,
The error is small.

That is, for example, in the example of n-12 above, the integer value X12a
-17 (odd number), the value of decimal value X], 2b is as follows:
-1)/4 10.1. Therefore, the value of position X12 at this time is
12 =X12a +X12b -17+0.1 -17.1. Therefore, the error with respect to the correct value of 16.9 is as small as 0.2 tracks.

Furthermore, as shown in FIG. 5, in areas where the integer value Xna is uncertain, that is, when the value of the burst level An or Bn is within a predetermined range, for example, 4.5 or more and 1.5 or less, the decimal value Xnb is changed. By setting Xnb-0,0, the error can be further reduced. In the above example, A12-1.4<1.5 or B1
2-4.6>4.5, so the current position X12
The value of is X12 - X12a + X12b -17+10 = 17.0. Therefore, the error with respect to the correct value of 16.9 is even smaller (0.1 track).

[Effects of the Invention] As described above, according to the present invention, by using the address code and the burst data A and B, the value of the current position of the head can be accurately detected as a real number including a decimal value.

Therefore, error fluctuations between the target speed and the detected speed can be reduced, and the head can be quickly and accurately moved to the target position.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a configuration according to an embodiment of the present invention, FIG. 2 is a diagram showing a data structure of a recording medium of the same embodiment,
FIG. 3 is a flowchart for explaining the operation of the same embodiment, FIGS. 4 and 5 are diagrams showing the relationship between the burst level and the head position, and FIG. 6 is a diagram showing the configuration of the speed table of the same embodiment. 7 is a diagram showing the relationship between the target speed and detected speed in the same embodiment, FIG. 8 is a diagram showing the configuration of a conventional speed table, and FIG. 9 is a diagram showing the relationship between the conventional target speed and detected speed. FIG. 10 is a diagram for explaining conventional head position detection. DESCRIPTION OF SYMBOLS 10... Disk, 11... Head, 12... Read circuit, 13... Erase detection circuit, 14... Address code detection circuit, 15... Burst data detection circuit, 16... Speed Table, 17...CPU, 1
8...VCM driver, 19...'VCM0 Applicant's agent Patent attorney Takehiko Suzue Diagram ■ Diagram Diagram

Claims (1)

[Claims] A recording medium having an address code indicating a cylinder number for each sector, and burst data A and B recorded at positions shifted by half a track from the center position of the track, and on this recording medium. a head for recording/reproducing data; an address code detecting means for detecting the address code from the read signal of the head; and an address code detecting means for detecting the address code from the read signal of the head; a first position information calculation means for calculating a value corresponding to an integer part of position information indicating the current position of the head; and the burst data A, B from the read signal of the head.
burst data detection means for detecting each level of the burst data A and B; and a second burst data detection means for calculating a value corresponding to the decimal part of the position information based on each level of the burst data A and B detected by the burst data detection means. Based on the position information consisting of an integer value and a decimal value calculated by the position information calculation means and the first and second position information calculation means,
comprising a distance calculation means for calculating the remaining distance from the current position of the head to the target position, and a speed calculation means for calculating a target speed according to the remaining distance calculated by the distance calculation means, A speed control device for a data recording/reproducing apparatus, characterized in that the moving speed of the head is controlled based on the target speed calculated by a speed calculation means.