KR100640644B1 - Method for compensating torque constant of each drive according to ambient temperature - Google Patents

Abstract

A method for compensating a drive-classified torque constant according to a temperature is provided to improve the reliability of a drive for temperature change in consideration of drive-classified temperature characteristic deflection by obtaining a torque constant compensation function according to a drive-classified temperature and applying a torque constant compensation value according to drive operation temperature change by using the torque constant compensation function. A torque constant compensation value of a drive is measured in the first temperature(500). A torque constant compensation value of the drive is measured in the second temperature having a temperature level which is higher than the first temperature(510). A torque constant compensation function is obtained by using temperature values of the first temperature and the second temperature, the torque constant compensation value measured in the first temperature, and the torque constant compensation value measured in the second temperature(520,530). The obtained torque constant compensation function is stored.

Description

Method for compensating torque constant of each drive according to ambient temperature}

1 is a torque constant graph according to a method of compensating a conventional torque constant Kt.

2 shows a configuration of a hard disk drive to which the present invention is applied.

3 is a block diagram of the torque constant compensation function setting apparatus according to the present invention.

4 is a block diagram of a torque constant compensator according to the present invention.

5 is a flowchart of a torque constant compensation method according to the present invention.

FIG. 6 is a detailed flowchart of a process of measuring a torque constant compensation value and obtaining a torque constant compensation function in FIG. 5.

7 is a graph of the torque constant compensation value according to the temperature according to the present invention.

8 is a graph of the torque constant compensation function obtained from three drives according to the present invention.

FIG. 9 is a detailed flowchart of a torque constant compensation function applying process in FIG. 5.

The present invention relates to a servo control system of a hard disk drive device, and more particularly, to a torque constant compensation method for each drive according to temperature.

Hard disk drives have the advantage of being able to reliably store large amounts of data and to access data at high speeds.

In general, hard disk drives require the ability of the head to move to and maintain a specific location on the disk for recording and playback of data. In addition, given the trend of larger applications and faster seek times, the average seek time and location maintenance (ie, track tracking) of a hard disk drive are important factors in determining overall product performance. As an element for controlling the average search time and the position holding characteristic, a voice coil motor (VCM 440, Voice Coil Motor) is mechanically included, and a servo control system including firmware is circuitally included. Can be mentioned. The torque constant of the VCM 440 is represented by Equation 1 below.

Kt = Bg * Le * R * Nc

(Bg is the magnetic flux density, Le is the effective length per turn of the coil, R is the torque-arm length, and Nc is the number of turns of the winding coil.)

The torque constant Kt of the ideal VCM 440 should be uniform according to the ambient temperature, but in practice the torque constant will increase as the ambient temperature rises.

1 is a torque constant graph according to a method of compensating a conventional torque constant Kt.

That is, before the VCM 440 executes the load and unload commands, the torque constant value is measured at regular intervals from the outer diameter (OD) to the inner diameter (ID) of the disk. After the storage is applied to the torque constant of the VCM (440).

However, according to the conventional torque constant compensation method, when the temperature of the disk drive rises or falls due to a change in the external environment, the torque constant cannot be compensated without loading and unloading, and the reliability of the drive according to the temperature change is maintained. There is a problem that can not be.

The technical problem to be achieved by the present invention is to obtain the torque constant compensation function according to the temperature for each drive and to apply the torque constant compensation value according to the drive operating temperature change by using the torque constant compensation function, taking into account the temperature characteristic variation of each drive temperature It is to provide a torque constant compensation method for each drive according to temperature to improve the reliability of the drive against change.

Another object of the present invention is to provide a torque constant compensation device for each drive to which a torque constant compensation method for each drive according to the temperature is applied.

In order to solve the above technical problem, the present invention provides a method for compensating for the torque constant of a hard disk drive, the method comprising: measuring a torque constant compensation value of a drive at a first temperature; Measuring a torque constant compensation value of the drive at 2 temperatures, a temperature value at the first and second temperatures, a torque constant compensation value measured at the first temperature, and a torque constant compensation value measured at the second temperature The method includes the steps of obtaining a torque constant compensation function and storing the obtained torque constant compensation function.

In order to solve the above technical problem, the present invention is a method for compensating the torque constant of the hard disk drive, the step of reading the torque constant compensation function in the hard disk drive, measuring the operating temperature of the drive, Obtaining a torque constant compensation value using the torque constant compensation function and the operating temperature value of the drive when the operating temperature of the drive changes to a predetermined reference value or more, and applying the obtained torque constant compensation value to the torque constant of the drive It includes.

In order to solve the above other technical problem, in the torque constant compensation function setting device of the hard disk drive, the temperature conversion unit for increasing or decreasing the temperature of the hard disk drive, measuring the temperature of the hard disk drive and the temperature value A temperature sensor for outputting a torque constant, a torque constant compensation value measuring unit for measuring the torque constant compensation value of the hard disk drive and outputting the torque constant compensation value, and controlling whether the temperature is increased or decreased in the temperature converter; And a measurement controller configured to receive an output temperature value and a torque constant compensation value output from the torque constant compensation value measuring unit, and obtain a torque constant compensation function based on the received torque constant compensation value.

In order to solve the above other technical problem, the present invention provides a torque constant compensation device of a hard disk drive, the maintenance cylinder for storing the torque constant compensation function according to the temperature of the drive, by measuring the temperature of the drive to measure the temperature value When the temperature change of the drive is changed by the temperature sensor to be output and the temperature value output by the temperature sensor is changed to a predetermined reference value or more, the torque constant compensation function is read from the maintenance cylinder, and the temperature value and the torque And a torque constant controller for obtaining a torque constant compensation value using a constant compensation function and applying the torque constant to a torque constant of the drive.

Hereinafter, the configuration of the present invention will be described with reference to the drawings.

2 shows a configuration of a hard disk drive 10 to which the present invention is applied.

The drive 10 includes at least one magnetic disk 12 that is rotated by a spindle motor 14. The drive 10 also includes a transducer 16 located adjacent the surface of the disk 12.

The transducer 16 can read or write information on the rotating disk 12 by sensing and magnetizing the magnetic field of each disk 12. Typically transducer 16 is coupled to the surface of each disk 12. Although illustrated and described as a single transducer 16, it should be understood that this consists of a write transducer for magnetizing the disc 12 and a separate read transducer for sensing the magnetic field of the disc 12. Read transducers are constructed from Magneto-Resistive (MR) devices.

The transducer 16 can be integrated into the slider 20. The slider 20 is structured to create an air bearing between the transducer 16 and the surface of the disk 12. The slider 20 is coupled to the head gimbal assembly 22. The head gimbal assembly 22 is attached to an actuator arm 24 having a voice coil 26. The voice coil 26 is located adjacent to the magnetic assembly 28 that specifies the voice coil motor 30 (VCM). The current supplied to the voice coil 26 generates a torque for rotating the actuator arm 24 relative to the bearing assembly 32. Rotation of the actuator arm 24 will move the transducer 16 across the disk 12 surface.

The information is typically stored in an annular track of the disc 12. Each track 34 generally includes a plurality of sectors. Each sector includes a data field and an identification field. The identification field is composed of a gray code identifying a sector and a track (cylinder). The transducer 16 is moved across the surface of the disc 12 to read or write information on other tracks.

3 is a block diagram of the torque constant compensation function setting apparatus according to the present invention.

Referring to FIG. 3, first, the temperature converter 300 is a device forcibly changing the temperature of a hard disk drive. Next, the temperature sensor 310 is a digital temperature measuring device that can accurately measure the temperature of the hard disk drive. Next, the measurement controller 320 controls the temperature converter 300, receives the measured values from the temperature sensor 310 and the torque constant compensation value measurer 350, calculates the torque constant compensation function, and calculates the memory 330. ) And the drive maintenance cylinder MC. Next, the memory 330 is a temporary storage place of the information transmitted by the measurement control unit 320. Next, 340 is a hard disk drive, and 345 is a maintenance cylinder MC embedded in the hard disk drive. Finally, the torque constant compensation value measuring unit 350 is a device for measuring the torque constant compensation value by measuring the torque constant gain value (Gain) of the drive. Normally, the torque constant gain value can be obtained by dividing the reference acceleration used in the servo design by the absolute value of the acceleration of the actuator of the drive.

4 is a block diagram of a torque constant compensator according to the present invention.

Referring to FIG. 4, first, 345 is a maintenance cylinder MC embedded in a hard disk. This area is mainly a place where information about drive operation is recorded. Next, the torque constant controller 410 reads the torque constant compensation function from the maintenance cylinder MC, receives the operating temperature value of the current drive from the temperature sensor 450, obtains the torque constant compensation value of the current operating temperature, and obtains it. Multiplied by the control signal and outputs to the DAC (420, Digital-to-Analog Converter). Next, the DAC 420 converts the digital control signal output from the torque constant controller 410 into an analog signal and transmits the digital control signal to the VCM driver 430. Next, the VCM driver 430 directly applies a current signal to the VCM 440 by directly controlling the driving of the VCM 440. Next, the VCM 440 causes the actuator to horizontally drive on the disc in accordance with the current signal input as the voice coil motor. Finally, the temperature sensor 450 is a digital temperature measuring device that measures the drive's current operating temperature.

5 is a flowchart of a torque constant compensation method according to the present invention.

Referring to FIG. 5, first, a torque constant compensation value for each drive is measured at a first temperature (step 500). This process is performed by measuring the torque constant of the drive using the torque constant compensation value measuring unit 350 while maintaining the temperature of the drive at a predetermined first temperature level.

Next, the torque constant compensation value for each drive is measured at the second temperature (step 510). This process is performed by measuring the torque constant of the drive using the torque constant compensation value measuring unit 350 while maintaining the temperature of the drive at a predetermined second temperature level. At this time, the first temperature level and the second temperature level are different temperature levels. At this time, the first temperature level may be set to a room temperature level and set to 25 degrees Celsius. At this time, the second temperature level may be set to a high temperature level and set to 60 degrees Celsius.

Next, the torque constant compensation function is calculated for each drive (step 520). This process is performed by finding the first-order function that connects the two points when the torque constant compensation value at the first temperature and the torque constant compensation value at the second temperature are plotted against the temperature. For example, if there are N drives from drive 1, drive 2, ..., drive N, each drive has different characteristics for temperature, and thus, N primary functions are obtained. That is, the torque constant compensation function Kt_comp (T) is

Kt_comp1 (T) = A1 * T + B1

Kt_comp2 (T) = A2 * T + B2

...

Kt_compN (T) = AN * T + BN

N will exist. At this time, A1, A2, ..., AN and B1, B2, ..., BN are constants, T is a temperature measurement value, and the torque constant compensation function Kt_comp (T) is a first-order function for temperature T. At this time, the constants of A1, A2, ..., AN and B1, B2, ..., BN are combined with the torque constant compensation value at the first temperature and the torque constant compensation value at the second temperature as the left side from above. It can be obtained through the solution of linear equations. At this time, the torque constant compensation function Kt_comp does not necessarily need to be a first-order function, and the torque constant compensation is determined by determining a third temperature, a fourth temperature, etc. in addition to the torque constant measurement values at the first and second temperatures. The function can be defined as a higher order function such as quadratic and tertiary functions for temperature T to reflect the precise characteristics of the drive.

At this time, the torque constant compensation function Kt_comp (T) suitable for each drive may be stored in the maintenance cylinders MC and 345 of each hard disk.

Finally, the torque constant compensation value according to the ambient temperature is obtained and applied to the drive (step 530). This process measures the current operating temperature of the drive by the temperature sensor 450, calls the torque constant compensation function stored in the maintenance cylinder (MC, 345) to obtain the torque constant compensation value at the current operating temperature to obtain a voice coil motor (VCM). , 440 may be applied to the torque constant.

FIG. 6 is a detailed flowchart of a process of measuring a torque constant compensation value and obtaining a torque constant compensation function in FIG. 5.

Referring to FIG. 6, first, a drive process is performed (operation 600). A drive process is a drive test process parallel to the manufacturing process of a hard disk drive.

Next, it is determined whether the temperature of the drive reaches the first temperature level (step 610). The first temperature level may be set to 25 degrees Celsius, which is room temperature as described above. In this case, if the drive temperature does not reach the first temperature level, the measurement controller increases or decreases the temperature of the drive using the temperature converter 300 and again determines whether the temperature of the drive reaches the first temperature level (611). , Process 610). At this time, if the temperature of the drive reaches the first temperature level, the process proceeds to the next step.

Next, the torque constant Kt compensation value of the drive is measured (step 612). This process is performed by measuring the torque constant of the drive using the torque constant compensation value measuring unit 350.

Next, the measured torque constant Kt compensation value is stored by the measurement controller 320 in the maintenance cylinders MC 345 or the memory 330 of the drive (step 613). This process is necessary to obtain the following torque constant compensation function.

Next, it is determined whether the temperature of the drive reaches the second temperature level (step 620). The second temperature level may be set to 60 degrees Celsius, which is a high temperature as described above. At this time, if the drive temperature does not reach the second temperature level, the measurement controller 320 uses the temperature converter 300 to increase or decrease the temperature of the drive and determine whether the temperature of the drive reaches the second temperature level. (Steps 621 and 620). At this time, if the temperature of the drive reaches the second temperature level, the process proceeds to the next step.

Next, the torque constant Kt compensation value of the drive is measured (step 622). This process is performed by measuring the torque constant of the drive using the torque constant compensation value measuring unit 350.

Next, the measured torque constant Kt compensation value is stored by the measurement controller 320 in the maintenance cylinders MC 345 or the memory 330 of the drive (step 623). This process is necessary to obtain the following torque constant compensation function.

Next, the measurement controller 320 obtains the torque constant compensation function Kt_comp and stores it in the maintenance cylinder MC 345 of the drive (step 630). This process saves the torque constant compensation function (Kt_comp) suitable for the unique temperature characteristics of each drive in the maintenance cylinder (MC, 345) of the drive, and calls it when the operating temperature changes during the operation of the drive. It is for. At this time, the torque constant compensation function Kt_comp does not necessarily need to be a first-order function, and the torque constant compensation is determined by determining a third temperature, a fourth temperature, etc. in addition to the torque constant measurement values at the first and second temperatures. The function can be defined as a higher-order function, such as quadratic or tertiary, to reflect the precise characteristics of the drive.

Finally, the drive process continues (step 640). This process can be followed by another test process or by finishing the drive manufacturing process.

7 is a graph of the torque constant compensation value according to the temperature according to the present invention.

In Fig. 7, the axis of abscissas is the cylinder number, which represents the position on the disc, and the axis of ordinates is the torque constant compensation value. 700 is a torque constant compensation value graph at 25 degrees Celsius as the first temperature, and 710 is a torque constant compensation value graph at 60 degrees Celsius as the second temperature. In this case, in addition to the torque constant measurement values at the first temperature and the second temperature, the third temperature, the fourth temperature, and the like may be determined, and the torque constant may be measured and displayed in a graph. In this way, the torque constant compensation function may be determined as a secondary function, a tertiary function, or the like.

8 is a graph of the torque constant compensation function obtained from three drives according to the present invention.

In FIG. 8, 800 is a graph of the torque constant compensation function obtained from the third drive, the 810 the second drive, and the 820 the first drive. As shown in this graph, the torque constant compensation value or the variation range of each drive is different for each drive, and to reduce the search error, a torque constant compensation function suitable for each drive is required as in the present invention.

FIG. 9 is a detailed flowchart of a torque constant compensation function applying process in FIG. 5.

When the hard disk drive is started, the drive itself reads information in the maintenance cylinder (MC) area of the disk and stores the information in the memory built into the drive. The torque constant compensation function application process assumes an initialization completion state in which the drive is started and the torque constant compensation function stored in the maintenance cylinder MC 345 is stored in the memory of the drive.

Referring to FIG. 9, first, a temperature of a current drive is measured (operation 900). This process is accomplished by measuring the operating temperature of the drive through a temperature sensor 450 built into the drive.

Next, it is determined whether the temperature change of the drive exceeds a reference value (step 910). The reference value can be set to 1 degree Celsius, 2 degrees Celsius, 10 degrees Celsius, etc. according to the judgment of a person skilled in the art. When the reference value is made small, for example, the voice coil motor (VCM, 440) can be controlled with a torque constant suitable for 1 degree Celsius and a small temperature change immediately, so that precise search is possible, but logic must be applied each time to compensate the torque constant. Therefore, the search speed may be slow. On the other hand, when the reference value is increased, the torque constant is compensated only for a large temperature change, for example, 10 degrees Celsius, so that precise search becomes difficult, but it may help to improve the search speed. At this time, if the temperature of the drive does not change by the reference value, the process is completed. At this time, if the temperature of the drive changes by the reference value, it proceeds to the next step.

Next, the torque constant compensation function is called (step 920). This process is a process in which the torque constant control unit 410 reads the torque constant compensation function stored in the memory of the drive.

Next, the torque constant compensation value suitable for the drive is calculated using the torque constant compensation function (step 930). In this process, the torque constant controller 410 obtains a torque constant compensation value suitable for the drive at the current temperature by substituting the operation temperature value of the current drive measured above into the called torque constant compensation function.

Finally, the obtained torque constant compensation value is applied to the torque constant of the voice coil motor (VCM) 440 (step 940). In this process, the operation of the voice coil motor is controlled by the control signal multiplied by the acceleration control signal and the torque constant, so that the torque constant controller 410 applies the torque constant compensation value obtained above to the torque constant so as to be suitable for the current temperature. The process of obtaining a control signal of the motor (VCM) 440 and outputting it.

Preferably, the first temperature level may be set to a room temperature level and set to 25 degrees Celsius. At this time, the second temperature level may be set to a high temperature level and set to 60 degrees Celsius.

Preferably, the torque constant may be measured for each drive at the third temperature level and the fourth temperature level in addition to the first temperature level and the second temperature level.

Preferably, the torque constant compensation function Kt_comp (T) suitable for each drive may be stored in the maintenance cylinders MC and 345 of each hard disk.

Preferably, the torque constant compensation function Kt_comp determines the torque constant by determining the third temperature, the fourth temperature, etc. in addition to the torque constant measured values at the first temperature and the second temperature, thereby determining the torque constant compensation function as a secondary function, It can be determined by higher-order functions such as tertiary functions.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary and will be understood by those of ordinary skill in the art that various modifications and variations can be made therefrom. However, such modifications should be considered to be within the technical protection scope of the present invention. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

As described above, according to the present invention, by compensating the torque constant value suitable for the operating temperature according to the change in the operating temperature of the hard disk drive, it is possible to prevent a search error caused by the change of the torque constant according to the change of temperature, and drive By compensating the torque constant by considering the variation of temperature characteristics, it is effective to maintain temperature reliability even in hard disks with insufficient margin for error.

Claims (5)

In the method for compensating the torque constant of the hard disk drive, Measuring a torque constant compensation value of the drive at the first temperature; Measuring a torque constant compensation value of the drive at a second temperature, the temperature level being higher than the first temperature; Obtaining a torque constant compensation function using temperature values at the first and second temperatures, torque constant compensation values measured at the first temperature, and torque constant compensation values measured at the second temperature; And And storing the obtained torque constant compensation function according to temperature. The method of claim 1, Wherein the first temperature is 25 degrees Celsius, the second temperature is 60 degrees Celsius, characterized in that the torque constant compensation method for each drive according to the temperature. In the method for compensating the torque constant of the hard disk drive, Reading a torque constant compensation function from the hard disk drive; Measuring an operating temperature of the drive; Obtaining a torque constant compensation value by using the torque constant compensation function and an operating temperature value of the drive when the operating temperature of the drive changes by more than a predetermined reference value; And And applying the obtained torque constant compensation value to the torque constant of the drive. In the torque constant compensation function setting device of the hard disk drive, A temperature converter configured to increase or decrease a temperature of the hard disk drive; A temperature sensor measuring a temperature of the hard disk drive and outputting the temperature value; A torque constant compensation value measuring unit configured to measure a torque constant compensation value of the hard disk drive and output the torque constant compensation value; And A measurement controller which controls whether the temperature converter increases or decreases the temperature, receives a temperature constant output from the temperature sensor and a torque constant compensation value output from the torque constant compensation value measurement unit, and calculates a torque constant compensation function based on the input; Torque constant compensation device according to the temperature, characterized in that it comprises a. In the torque constant compensation device of a hard disk drive, A maintenance cylinder for storing a torque constant compensation function according to the temperature of the drive; A temperature sensor measuring a temperature of the drive and outputting a temperature value; When the temperature change of the drive is changed by more than a predetermined reference value by receiving the temperature value output by the temperature sensor, the torque constant compensation function is read from the maintenance cylinder, and the torque constant is determined by the temperature value and the torque constant compensation function. Torque constant compensation device according to the temperature, characterized in that it comprises a torque constant control unit for obtaining a compensation value applied to the torque constant of the drive.

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