KR100365618B1 - Method for removing stiction error of hard disk drive - Google Patents

Abstract

PURPOSE: A method for removing a stiction error of a hard disk drive is provided to maximize the effect of removing the stiction error by reducing a frictional force between a head and a disk. CONSTITUTION: A microcontroller outputs a start-on signal to a spindle motor driving part to drive a spindle motor(50). The microcontroller examines whether a ready signal is received from the spindle motor driving part(52). If so, the microcontroller unlatches a head and measures bias(58). Otherwise, the microcontroller controls the spindle motor driving part and a VCM(Voice Coil Motor) driving part to apply high frequency input to a VCM and the spindle motor at the same timing to shake the spindle motor and the VCM for a stiction error generated period(54). The microcontroller examines whether the ready signal is received from the spindle motor driving part(56). If so, the microcontroller terminates the bias-measurement according to an initializing program and converts a state into a drive ready state. Otherwise, the microcontroller reports an error situation to a host computer.

Description

How to eliminate stiction error on hard disk drive.

TECHNICAL FIELD The present invention relates to hard disk drives, and more particularly, to a method for eliminating stiction errors occurring between a head and a disk.

A hard disk drive is a device for magnetically recording data on a rotating disk or reading data recorded on a disk, and is widely used as a secondary memory device of a computer system because a large amount of data can be accessed at high speed. FIG. 1 is a schematic block diagram of a typical hard disk drive. Hereinafter, the stiction phenomenon between the head and the disk of the hard disk drive will be described with reference to FIG. 1.

In FIG. 1, the disk 10, which is a recording medium, is rotated by the spindle motor 32. As shown in FIG. The head 12 is located on the surface of the disk 10 and is mounted to a vertically extending arm 14 of an arm assembly of a voice coil motor (hereinafter referred to as VCM) 28. . The preamplifier 16 preamplifies the signal picked up by the head 12 at the time of data reading, and the encoded recording data applied from the read / write channel 18 by driving the head 12 to the data storage. Write Data) Write the EWD to the disc 10. The read / write channel 18 is referred to as a preamplifier 16, an analog-to-digital converter (A / D converter) 20, and a disk data controller (DDC). Data pulse from the preamplified signal in the preamplifier 16 and sequentially applies the encoded and decoded read data RDATA to the DDC 34 or the write data WDATA applied from the DDC 34. Is encoded and applied to the preamplifier 16. The read / write channel 18 also detects the analog reading signal from the preamplified signal in the preamplifier 16 and applies it to the A / D converter 20. The A / D converter 20 is connected to the read / write channel 18 to receive an analog servo reading signal, and digitally converts the input signal to PES to output to the microcontroller 22. The microcontroller 22 is connected to the DDC 34 and controls track search and track following. In addition, the microcontroller 22 controls the track following using the PES value applied from the A / D converter 20. A digital-to-analog converter (D / A converter) 24 is connected to the microcontroller 22 and the VCM driver 26 to control digital control input signals U from the microcontroller 22. ) Is converted into an analog signal and output to the VCM driver 26. The VCM driver 26 is connected to the spindle motor 28 and the D / A converter 24 and controls the driving of the VCM 28 under the control of the microcontroller 22. The VCM 28 moves the head 12 on the disk 10 in correspondence with the direction and level of the drive current applied from the VCM driver 26. The spindle motor driver 30 controls the driving of the spindle motor 32 under the control of the microcontroller 22 and applies a ready signal to the microcontroller 22 when the spindle motor 32 rotates at a constant speed. The spindle motor 32 rotates the disk 10 under the control of the spindle motor driver 30. The DDC 34 records data received from the host computer on the disk 10 through the read / write channel 18 or recorded on the disk 10 in response to a read / write name received from the host computer. Read the data and transfer it to the host computer. The DDC 34 also interfaces the servo control of the microcontroller 22 in response to read / write commands received from the host computer. When power is supplied to the hard disk drive having the above-described configuration, the spindle motor 32 starts to rotate according to the initialization program. When the rotational speed of the spindle motor 32 reaches about 1000 [RPM], the head 12 floats on the disk 10, and the VCM when the spindle motor 32 is at the normal speed (for example, 4500 [RPM]). 28 starts to move. However, if the friction force between the head 12 and the disk 10 is greater than the starting torque of the spindle motor 32 before the operating power is supplied to the adhesive disk drive, the spindle motor 32 may be applied even if the operating power is applied to the hard disk drive. Does not rotate. This phenomenon is called a stiction error. There are various reasons for the generation of the stiction error, such as the shape and the processing accuracy of the head 12 and the disk 10. A method of eliminating a stiction error caused by various reasons described above will be described with reference to FIG.

FIG. 2 shows a conventional control flow diagram for eliminating the stiction error occurring between the head 12 and the disk 10 of the hard disk drive, which will be described in detail with reference to FIGS. 1 and 2. First, when the power of the hard disk drive is "on", the microcontroller 22 initializes each part of the hard disk drive according to the initialization program in step 40 and starts the start-on for driving the spindle motor 32. Outputs a signal. Thereafter, in step 42, the microcontroller 22 checks whether the ready signal is received from the spindle motor driver 30. In other words, check if the spindle motor is ready. When the test result is received, the microcontroller 22 proceeds to step 48 and completes the bias-measurement according to the initialization program, and then switches to the HDD ready state. On the other hand, if the ready signal is not received in step 42, the microcontroller 22 proceeds to step 44 and shakes the spindle motor 32 to proceed to step 46. In the shaking method, the spindle motor driving unit 30 is controlled to apply a high frequency input (that is, a high frequency voltage or a current) to the spindle motor 32. In step 46, the microcontroller 22 checks whether the ready signal is received, and if the ready signal is not received, reports the error situation to the host computer through the DDC 34 and terminates the stiction error elimination process. On the other hand, if there is a test result ready in step 46, the microcontroller 22 proceeds to step 48 and completes the bias-measurement according to the initialization program, and then switches to the drive ready state. As described above, the conventional hard disk drive applies a high frequency voltage or current to the spindle motor 32 so as to reduce friction between the head 12 and the disk 10 due to the vibration of the spindle when a stiction error occurs. As a result, the stiction error was eliminated. In addition, when the high frequency voltage or current is applied to the spindle motor 32 to shake the spindle motor 32, but the stiction error is not eliminated as described above, the high frequency voltage or current is sequentially applied to the VCM 28 so that the VCM ( 28) we tried to eliminate the stiction error by shaking. However, in the conventional hard disk drive, only the spindle motor shaking or the spindle motor shaking and the VCM are sequentially performed, thereby preventing the effect of eliminating the stiction error.

Accordingly, an object of the present invention is to provide a method for eliminating stiction errors by maximally reducing friction between the head and the disk by matching the shaking timing of the spindle motor and the shaking timing of the VCM when a stiction error occurs in the hard disk drive. have.

Hereinafter, exemplary operations of the present invention will be described in detail with reference to the accompanying drawings. Many specific details are set forth in order to provide a more thorough understanding of the present invention, such as the specific processing flows set forth in the following description and the accompanying drawings. It will be apparent to those skilled in the art that the present invention may be practiced without these specific details. Detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

3 is a diagram illustrating a control flow diagram for eliminating stiction errors occurring between the head 12 and the disk 10 of the hard disk drive as an embodiment of the present invention, and FIG. The timing diagram of the shaking operation of the spindle motor 32 and the VCM 28 during the process is illustrated. (A) of FIG. 4 is a timing diagram when a stiction error occurs at the time T1, and (B) and (C) are the shaking timings of the spindle motor 32 and the VCM 28 at the time T1 and T2, respectively. Is shown. Hereinafter, the process of eliminating the stiction error according to the present invention will be described with reference to FIGS. 1 and 3 and 4.

First, when the power of the hard disk drive is "on", the microcontroller 22 performs a start-on signal for driving the spindle motor 32 while performing general initialization operations such as initializing variables of the hard disk drive in step 50. Output to the spindle motor drive unit 30. Accordingly, the spindle motor 32 is driven. Thereafter, in step 52, the microcontroller 22 checks whether a ready signal indicating the ready state of the spindle motor 32 is received from the spindle motor driver 30, and proceeds to step 58 when the ready signal is received. In step 58, the microcontroller 48 unlatches the head 12, and after completing the bias-measurement according to the initialization program, switches to the HDD ready state. On the other hand, when the ready signal is not received in step 52, the microcontroller 22 proceeds to step 54 and the VCM 28 at the same timing (T1, T2) as shown in FIGS. 4B and 4C. And the spindle motor driver 30 and the VCM driver 26 to apply a high frequency input to the spindle motor 32. As a result, the spindle motor 32 and the VCM 28 perform the shaking operation at the same timing (T1, T2) during the stiction error occurrence period. As a result, the actuator and the spindle vibrate to reduce the friction force between the head 12 and the disk 10, thereby eliminating the stiction error. Thereafter, in step 56, the microcontroller 22 checks whether the ready signal is received from the spindle motor driver 30. When the ready signal is received, the microcontroller 22 proceeds to step 58 described above to complete the bias-measurement according to the initialization program. Switch to ready state. On the other hand, if the ready signal is not received in step 56, the microcontroller 22 reports the error situation to the host computer through the DDC 34 and terminates the above-described stiction error elimination process.

As described above, the present invention reduces the frictional force between the head and the disk by applying a high frequency voltage or a high frequency current to the spindle motor and the VCM at the same time when a stiction error occurs in the hard disk drive. There is an advantage to maximize.

1 is a schematic block diagram of a general hard disk drive.

2 is a conventional control flow diagram for eliminating stiction errors occurring between a head and a disk of a hard disk drive.

3 is a control flow diagram for removing a stiction error generated between the head and the disk of the hard disk drive as an embodiment of the present invention.

4 is a timing diagram of the shaking operation of the spindle motor and the voice coil motor according to the present invention.

Claims (3)

In the method of eliminating the stiction error of the hard disk drive, A stiction error checking process for checking whether a stiction error occurs between the head and the spindle motor, which are recording media after the operating power of the hard disk drive is applied; And a shaking process of shaking the spindle motor and the voice coil motor at the same time when the test result indicates a stiction error. The method of claim 1, wherein the shaking process A method of eliminating stiction errors in a hard disk drive, characterized in that the voice coil motor is shaken during the shaking timing of the spindle motor or the spindle motor shakes during the shake of the voice coil motor. The method of claim 2, wherein the shaking process may be repeated one or more times before the stiction error is removed.