KR950003829B1 - Track access device and method of disk driver - Google Patents

Abstract

The track accessing device of a disk driver includes a digital-analog converting part for analog-converting the digital logic result of a track access mode; and a voice-coil type motor driver for driving the head by controlling the voice coil type motor according to the output of the digital-analog converting part, and for outputting and recording the necessary data by shifting the head on the data recording medium driven by the driving motor.

Description

Track Access Device of Disk Drive and Its Access Method

1 is a block diagram of a track access device of a disk drive according to an embodiment of the present invention.

2 is a view for explaining a current profile and a head moving position profile applied to the present invention.

3 is a flowchart for explaining a track access method of a disk drive according to the present invention.

4 is a graph illustrating the head position response characteristic according to the track access method close to the present invention.

* Explanation of symbols for main parts of the drawings

1: Servo information detection unit 2: Mode switching unit

3: Current profile generator 4: Position deviation detector

5: fine track tracking control unit 6: digital-analog conversion unit

7: Voice coil type motor driving part 8: Voice coil type motor

9: Head speed detector 10: Target speed generator

11: speed controller

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a track access device and a method of accessing a disk drive, and more particularly, to a track access device and a method of accessing a disk drive, which perform a track movement on an information storage medium at high speed in a hard disk drive or an optical disk drive. will be.

In general, a hard disk drive or an optical disk drive is used as a peripheral device for recording information on a disk capable of storing a large amount of information or reading information recorded on the disk. Information is recorded by dividing the recording area into a plurality of tracks. Therefore, in order to record information on the information storage medium or to read recorded information, it is necessary to track-move a head for reading or recording information as necessary.

By the way, in the track access method on the information storage medium, the speed profile control method and the PID control method are known. The speed profile control method is mainly a control algorithm used for moving tracks, whereas the PID control method is usually used. The control algorithm is applied to the track following operation.

The track access time of the head on the information storage medium is related to the product performance of the disk drive, in particular the movement from the track where the head is currently located to the nearest track (e.g. 1-track movement) is stochastic frequently on the disk drive. This near track travel time reduction is an important factor in product design specifications. In this case, if the above-described speed profile control method is used for the near track movement, the resolution for the near track movement request is deteriorated, and the time for positioning the head on the track becomes longer, and the PID control method is used. In this case, there is a problem that the access time for the track is lengthened because the driving power is limited. That is, the distance corresponding to the near track on the information storage medium is considerably smaller in the velocity profile control method applied to the distant track movement access, so that the resolution of the control operation is degraded. When used as it is for the near track access, since the close track corresponds to a relatively large distance, the driving power becomes saturated and it is easy to be non-linear control, and the head positioning time becomes long.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the prior art, and is divided into a long distance and a close distance according to the moving distance of the head, and in case of a close distance, an appropriate current profile required for close track access on the information storage medium is provided. The disk drive track access device, which is designed to control the head in an open loop method according to its current profile, and then finely adjust by the track tracking mode used for track tracking to realize near track access quickly and its The purpose is to provide an access method.

In order to achieve the above object, according to the present invention, a disc drive configured to read or write necessary information by moving a head (HD) on an information storage medium driven by a drive motor (SM), the information storage medium The first track access mode by the servo information detection unit 1 for generating the position information of the head on the track, and by a track movement command input from the outside based on the head position and the track information from the servo information detection unit 1; A mode switching unit 2 for automatically switching between the second track access mode and the third track access mode, and in the case of close track movement, a current profile required for performing the first track access mode is created by switching the mode switching unit 2; After the track access is performed for a predetermined sampling time by the current profile creating section 3 and the first track access mode, the second track access mode is automatically switched. Head speed detection section 4 for detecting positional deviation of the head relative to the track, fine track tracking control section 5 for performing fine track tracking control for the deviation detected by the position deviation detection section 4, and third track access mode. When the distant tracks are the same, the head speed is detected by the third track access mode by switching between the target speed generating unit 10 and the mode switching unit 2 which generate the target moving speed of the head according to the moving distance of the head. The speed profile type speed controller 11 which generates a control input according to the difference of the head speed detection part 9, the target speed generation part 10, and the head speed detection part 9, and enables high-speed access, The said 1st The digital-analog converter 6 for analog-converting the digital calculation results of the second and third track access modes, and controls the voice coil motor 8 according to the output of the digital-analog converter 6 Voiceco accesses (HD) track access The track access device of the disk drive, characterized in that configured in type motor drive unit (7) is provided.

According to the present invention, there is provided a method of reading servo pattern information for track access and a first track access mode, a second track access mode, and a third track access mode according to an input of a track movement command input from the outside. A mode switching step of switching and connecting according to the track moving distance, creating a current profile required for the first track access mode, detecting a positional deviation between the track and the head when switching to the second track access mode, and as much as this position deviation Fine tracking access of the track, detecting the speed of the head when switching to the third track access mode, generating a target speed that the head should have according to the moving distance of the head, the target speed of the head and the current of the head Speed control by speed profile method by speed difference, and analog conversion of digital results obtained in first, second and third track access modes There is provided a track access method of a disk drive consisting of performing a movement track by driving the voice coil motors according to the analog conversion result.

According to the track access apparatus and the access method of the disc drive according to the present invention as described above, when the near tracks are the same, that is, when the number of track movements is smaller than the predetermined head use reference value, the current is appropriate for several sampling times in the first track access mode. By driving the head by the profile and then automatically switching to the second track access mode, fine adjustment can be performed to quickly realize close track movement.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail with reference to drawings.

1 is a block diagram of a track access apparatus of a disk drive according to the present invention, FIG. 2 is a flowchart illustrating a track access method of the disk drive according to the present invention, and FIG. 3 is a current profile shown in FIG. It is a diagram illustrating a current profile generated by the unit and the head moving state according to the current profile.

1 and 2, information is recorded / read by the head HD on the disk DS as the information storage medium rotated by the spindle motor SM as the drive motor, in which case the disk DS. Servo pattern information such as track information and the like is detected by the servo information detection unit 1. In this state, when a track movement command is input (FIG. S21), the mode switching unit 2 applies a near track movement instruction (first track access mode) based on the preset head movement reference value C ₁ or a motion track movement instruction. In the case of a close track movement command (S22 in FIG. 2), the mode switching unit 2 determines the track movement mode (first track access mode) that is close in step S23 in FIG. Mode (second track access mode), and if there is a near track movement (0 < track movement number &_lt; C ₁ ), step S24 automatically switches to the terminal a side to operate in the first track access mode. In the current profile preparing section 3, the position of the head HD is quickly positioned at the center of the moving track in consideration of various parameters such as torque, inertia, driving current, etc. related to the voice coil-type motor 8 and the head HD. The top of the head with the ship As small as possible, the moving speed and the overshoot (overshoot) occurs the current pro right file consisting of first a period t1 ~ t4 shown in FIG. 3 that is designed not to occur (FIG. 2 S25) and executes the movement of the nearest track. That is, the data is analog-converted by the digital-analog converter 6 according to the current profile and then applied to the voice coil type motor driver 7 so that the voice coil type motor driver 7 is the voice coil type motor 8. To drive the head HD along the movement position trajectory of the head as shown in FIG.

When the drive proceeds to the section t4 in the current profile of FIG. 3 by the track movement, a minute position error? Is generated between the head and the track as shown in FIG. Therefore, the mode switching unit 2 is automatically switched to the terminal b side after the section t4 to perform fine tracking access as the second mode, that is, PID control. In this case, when the position deviation ε is detected by the position deviation detection unit 4 and the position deviation is applied to the fine track tracking controller 5, the fine track tracking controller 5 operates the track following by the normal PID method. The data for outputting the data is outputted, and the data is analog-converted by the digital-analog converter 6 as described above, and the voice coil type motor driver 7 is applied. Accordingly, the voice coil type motor driver 7 drives the voice coil type motor 8 according to the applied data to perform the fine tracking operation so that the head HD is positioned on the track (FIG. 2 S28). .

On the contrary, if the track following command is received in step S23, the mode switching unit 2 switches to the terminal b to switch to the track following mode in step S29 to perform the operation of step S28.

On the other hand, when a track movement command far from step S22 is applied to the mode switching unit 2 (track shift number> C ₁ ), the mode switching unit 2 is switched to the terminal C side to operate in the third access mode (the 2 (S30), and thus, based on the output of the target speed generator 10 and the head speed detector 9, the target speed that the head should have is compared with the current speed of the head according to the head moving distance, and according to the difference The so-called speed profile method of controlling the speed of the head is performed by the speed controller 11 so as to access the track with a minimum time within a range that does not impair the stability of the position control system (FIG. S31). Then, the track access mode is switched to enter the fine track tracking control mode (FIG. 2 S32).

4 is a view showing a comparison between the track access time required when the track access is performed by the track access method of the disk drive according to the present invention and the time required when the track access is performed by the conventional method. The method (curve a) according to the present invention is conventional for a settling time, i.e., a time required to satisfy the condition S33 in which the write / read operation S34 shown in FIG. 2 is possible. It can be seen that the time response characteristic is excellent because it is reached more accurately than the method (curve b).

As described above, the track access time can be shortened by performing a close track access by the open loop method and the conventional PID method of the disc drive according to the present invention, and the data processing speed of the disc drive is increased. Can be improved.

Claims (10)

The digital-analog converter 6 for analog-converting the digital calculation result of the track access mode and the voice coil motor 8 are controlled in accordance with the output of the digital-analog converter 6 to track the head HD. A disk drive comprising a voice coil type motor drive unit 7 for accessing a head drive on an information recording medium driven by a drive motor to continuously output or record necessary information, wherein the head is positioned on the information recording medium. The first track access mode, the second track access mode, and the first track access mode and the first track access mode and the first track access mode are based on the generated servo information detection unit 1 and track movement commands input from the outside based on the head position and track information from the servo information detection unit 1. The mode switching unit 2 for automatically switching the track access mode and the mode switching unit 2 in the case of close track movement are used to perform the first track access mode. The positional deviation of the head relative to the track is made by the current profile creating section 3 which creates the required current profile and the second track access mode which is automatically switched after the track access is performed for a predetermined sampling time by the first track access mode. The head position deviation detection unit 4 for detecting, the fine track tracking control unit 5 for performing fine track tracking control for the deviation detected by the head position deviation detection unit 4, and the distant track movement of the third track access mode. In this case, the target speed generating unit 10 generates a moving target of the head according to the moving distance of the head, and the head speed detecting unit 9 detects the head speed by the second track access mode by switching of the mode switching unit 2. And a speed controller 11 for generating a control input according to the difference between the target speed generator 10 and the head speed detector 9 so as to perform a speed profile type track access to enable fast access. Track access device of a disk drive, characterized in that is configured to include. 2. The track access apparatus according to claim 1, wherein the mode switching unit (2) switches the track access number corresponding to the track movement number for moving the head by comparing the track movement number with a predetermined value. . The method according to claim 1 or 2, further comprising a current profile creation section (3) for creating a current profile for performing the first track access mode in the case of a close track movement with a smaller number of tracks than the predetermined value. A track drive device for a disc drive. 3. The disk according to claim 2, wherein the mode switching unit (2) automatically switches to the second track access mode, which is a fine track access mode, after the track access is performed by the first track access mode. Drive's track access device. 4. The track access apparatus according to claim 3, wherein the current profile created from the current profile creating section (3) is a moving speed and a position control profile of the head. A track access method of a disc drive that performs track movement using subpattern information for track access, comprising the steps of: reading servo pattern information for track access; and a track by input of a track movement command input from the outside. A mode switching step of switching between the first track access mode, the second track access mode, and the third track access mode according to the movement distance, detecting the positional deviation between the track and the head when the second track access mode is switched; Fine tracking access of the track by the positional deviation, detecting the speed of the head when switching to the third track access mode, generating a target speed that the head should have according to the moving distance of the head, and Speed control by the target speed of the head and the current speed difference of the head, and obtain the first, second and third track access modes. And a track movement by driving the voice coil-type motor according to the result of the advance. 7. The track access method according to claim 6, wherein the track access mode switching is performed so as to correspond to the track movement number by comparing the track movement number with a predetermined value. 8. The method according to claim 6 or 7, further comprising a current profile generating step of creating a current profile for performing the first track access mode when the number of track movements is smaller than a predetermined value (in the case of a close track movement). Track access method of a disk drive. 8. The track access according to claim 7, wherein the mode switching step causes the track access to be performed by the first track access mode, and then automatically switches to the second track access mode which is a fine track access mode. Way. 10. The method of claim 8, wherein the current profile is a movement speed and a position control profile of the head.