JP2642929B2 - How to adjust the position sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in the following order.

A Industrial application field B Outline of the invention C Conventional technology (FIGS. 6 to 8) D Problems to be solved by the invention (FIGS. 6 and 8) E Means for solving the problems (FIGS. 1 to 6 and 8) F operation (FIGS. 1, 2, 4 to 5 and 8) G embodiment (G1) Configuration of the embodiment (FIG. 3) (G2) Speed adjustment method (FIG. 1, FIG. 3, FIG. 4, and FIG. 6 to FIG. 8) (G3) Phase difference adjustment method (FIG. 2, FIG. 3) FIG. 5 and FIG.
(FIG. 8) (G4) Other Embodiments H Effect of the Invention A Industrial Field of the Invention The present invention relates to a method for adjusting a position sensor, for example, a method of detecting the position of a head in a hard disk device by optical means. The present invention can be applied to a method for adjusting the position sensor.

B. Summary of the Invention The present invention relies on the relative movement of the scale and the sensor,
In a position sensor adjustment method for obtaining a plurality of triangular waveform detection outputs having different phases, a speed detection error can be adjusted by adjusting a differential value of each detection output to a predetermined value, and By individually adjusting the voltage level of each detection output, the phase shift between each detection output can be adjusted.

C. Prior Art In this type of hard disk device, a plurality of recording tracks formed concentrically on a magnetic disk are tracked by moving a head mounted on a head arm in a radial direction of the disk-shaped magnetic disk. It has been made possible.

As shown in FIG. 6, such a hard disk device 1 has a head 3 mounted on one end of a Y-shaped head arm 4 and a rotating shaft 5 driven by a driving device including, for example, a voice coil motor 6. Is rotated in the radial direction of the magnetic disk 2 so as to be able to track on a large number of recording tracks formed concentrically on the magnetic disk 2.

At the other end of the head arm 4, a position sensor 9 of the optical sensor type is provided. The position sensor 9 includes a sensor 8 and a scale 7. For example, a slit having a width of 50 [μm] is formed on a light emitting portion such as an LED, a transparent glass member, or the like.
A reticle having a configuration of vapor deposition with a pitch of 0 [μm] and a sensor 8 in which light receiving portions made up of photodiodes and the like are arranged vertically, the head arm 4 has an integral structure made of a mold or the like.
It is attached to. In addition to this, the head arm 4 moves with the scale 7 attached to the chassis and having, for example, a slit of the same pattern as the reticle deposited on a transparent glass member or the like sandwiching the gap between the light emitting portion and the reticle. Accordingly, the aperture of the overlapping portion of the slit of the scale and the reticle fluctuates, and thus a detection output having a triangular waveform is obtained from the light receiving section.

Here, in a hard disk device particularly designed for high-density recording, the track interval between magnetic disks is 25 [μm], which is narrower than the slit interval between the scale 7 and the reticle. To each 50
Four reticles 10 each having slits 11A, 11B, 11C, and 11D each having a width of [μm] and a pitch of 100 μm.
A, 10B, 10C, and 10D are positioned so as to be shifted by 25 [μm] each. As a result, as shown in FIG. 8, four light receiving units provided below each of the reticles 10A, 10B, 10C, and 10D are used. To obtain four detection outputs S _A , S _B , S _C , and S _D having a phase difference of 90 ° from each other, so that each detection output S _A , S _B , S _C , and S _D is at the upper right. Over the specified voltage
By associating each recording track with X _A , X _B , X _C , and X _D (hereinafter referred to as detection points), detection outputs S _A , S _B , S _C, or S _D corresponding to the target recording track. Position sensor 9 that can position the head 3 in the just tracking state using
Is configured.

D Problems to be Solved by the Invention However, in the position sensor 9 having such a configuration,
For example, if the scale 7 and the sensor 8 are mounted in a displaced state, waveform distortion occurs in the detection outputs S _A , S _B , S _C , S _D , and the respective detection outputs S _A , S _B , S _C , There was a problem that the phase of _SD was shifted.

For this reason, conventionally, while increasing the mounting accuracy of the scale 7 or the sensor 8, each detection output S _A , S _B ,
The adjustment method of adjusting the maximum value and the minimum value of the triangular waves of S _C and S _D to a predetermined value was used, but in this case, the maximum value of each detection output S _A , S _B , S _C , and S _D was obtained. If the waveform roundness near the value and the minimum value is different, the slopes of the linear portions of the adjusted detection outputs S _A , S _B , S _C , and S _D are different, and the detection outputs S _A , S _B , S _C , and S _D , there is a possibility that an error may occur in the moving speed of the head arm 4 or that the phase shift cannot be eliminated, and eventually, tracking may not be possible in the just tracking state.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and it is an object of the present invention to propose a position sensor adjustment method that can solve the problems of the conventional position sensor adjustment method at a glance.

Means for Solving E Problem In order to solve such a problem, in the first invention,
When each detection output of a triangular waveform having a different phase obtained by the relative movement of the scale and the sensor rises or falls, a point exceeding a predetermined voltage is set as a detection point, and each recording track is made to correspond to the detection point. After adjusting the amplitude of each detection output so that the maximum value and the minimum value of each detection output become a predetermined value in the position sensor that detects the position of the head based on each detection output corresponding to each recording track. The scale and the sensor are moved at a predetermined speed, and each detection output of each detection output is set so that each differential value near each detection point obtained by differentiating each detection output obtained based on the movement result becomes a predetermined value. The amplitude was adjusted.

Further, in the second invention, when each detection output of a triangular wave shape having a different phase obtained by relative movement of the scale and the sensor rises or falls, a point exceeding a predetermined voltage is set as a detection point and the respective detection points are detected. Each position of each recording track corresponds to a point, and in a position sensor for detecting the position of the head based on each detection output corresponding to each recording track, the maximum value and the minimum value of each detection output become predetermined values. After adjusting the amplitude of the detection output, the scale and the sensor are moved at a predetermined speed, and each detection is performed so that the phase difference between each detection point of each detection output obtained based on the movement result becomes a predetermined phase difference. The output voltage was adjusted.

F acts detection outputs _{S A, S B, S C} , by adjusting the amplitude of S _D, the detection outputs _{S A, S B, S C} , variable to obtain the slope of the S _D, the differential value based on this Can be adjusted. Here, each detection output S _A , S _B , S _C ,
Since the differential value obtained by differentiating the _SD represents the moving speed of the scale 7 and the sensor 8, by obtaining a differential value corresponding to a predetermined speed, each detection output S _A , S _B , S _C , S _D
Can be effectively compensated for.

Further, each of the detection output _{S A, S B, S C} , by adjusting the voltage of S _D, a position detection outputs _{S A, S B, S C} , S D Kos a predetermined voltage
_{X A, X B, X C} , may adjust the X _D. Here, each detection output S _A ,
The phase difference between S _B , S _C , and S _D is detected based on the position X _A , X _B , X _C , X _D where one of the rising and the falling exceeds a predetermined voltage. Each detection output S _A , S _B ,
It can be effectively adjusted so that the phase difference between S _C and S _D becomes a predetermined phase difference.

G Example Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

(G1) Configuration of the Embodiment In the hard disk device 1 shown in FIGS. 6 to 8, four light receiving sections 12A, 12B, 12C, and 12D are provided below each of the reticles 10A, 10B, 10C, and 10D. The respective light receiving outputs P _A , P _B , P _C , and P _D are applied to respective detection circuits 13A, 13B, 13C, 13D in four series as shown in FIG.

In the detection circuits 13A, 13B, 13C, and 13D, each light-receiving output P _A ,
P _B , P _C , and P _D are first amplifier circuits 14A, 14B, and 14 of an operational amplifier configuration having negative feedback resistors VR _1A , VR _1B , VR _1C , and VR _1D.
C and 14D are provided to the inverting input terminals. Each amplifier circuit 14
The non-inverting input terminals of A, 14B, 14C, and 14D are connected to a common power supply VA. Thus the light receiving output _{P A, P B, P C} , amplifies the P _D, the variable resistor _{VR 1A, VR 1B, VR 1C} , the light receiving output in _{VR 1D P A, P B,} P C, P D Can be adjusted.

Also, the detection outputs S _A , S _B , of the amplification circuits 14A, 14B, 14C, 14D,
S _C and S _D are connected via resistors R _1A , R _1B , R _1C and R _1D , respectively.
One end is connected to the other end of the grounded variable resistors VR _2A , VR _2B , VR _2C , VR _2D , whereby the voltage adjustment circuits 15A, 15B, 15
C, 15D so that the phase of each detection output S _A , S _B , S _C , S _D can be adjusted by changing the resistance value of the variable resistors VR _2A , VR _2B , VR _2C , VR _2D It has been done.

In addition, each detection output of voltage adjustment circuit 15A, 15B, 15C, 15D
S _A , S _B , S _C , and S _D are second amplifier circuits 16A, 16B, 16 of an operational amplifier configuration having resistors R _2A , R _2B , R _2C , and R _2D for negative feedback.
C and 16D are input to the inverting input terminals, and the non-inverting input terminals are connected to the common power supply VB. The second amplifier circuits 16A, 16B,
The output terminals of 16C and 16D are connected to a switch circuit 17, and by selecting a detection output S _A , S _B , S _C or S _D corresponding to each recording track, the position of the recording track can be detected. Has been made.

(G2) Speed Adjustment Method In the position sensor 9 having the above configuration, for example, the sensor 8
And the detection output S _A ,
If waveform distortion occurs in S _B , S _C , and _SD , a speed error may occur. This error is corrected by adjusting the speed according to the processing procedure shown in FIG.

That is, the adjuster enters the processing procedure in step SP1, and in step SP2, finely moves the head arm 4 while visually observing the output waveform with, for example, an oscilloscope or the like, and adjusts the variable resistance for adjusting the amplitude of each of the detection circuits 13A, 13B, 13C and 13D. By adjusting VR _1A , VR _1B , VR _1C , VR _1D and the variable resistors VR _2A , VR _2B , VR _2C , VR _2D for voltage adjustment, each of the detection outputs S _A , S _B , S _C , S _D is adjusted. The maximum value and the minimum value are adjusted to specified values (for example, 9 [V] and 3 [V]).

In the following step SP3, for example, the head arm 4
Can be rotated at a predetermined speed.
, The head arm 4 is moved at a constant speed.

In the following step SP4, the head arm 4
Each of the detection outputs S _A , S _B , S _C , and S _D obtained by the movement of the sensor is differentiated through, for example, a differentiating circuit, and the resulting differential waveform is visually observed with an oscilloscope or the like. _{a, S B, S C,} S detection points _{D X a, X B, X} C, X D
Adjustment is performed using the variable resistors VR _1A , VR _1B , VR _1C , and VR _1D for amplitude adjustment so that the differential value in the vicinity becomes a specified value.

For example, as shown in FIG. 4 (B), the first detection output S _A1 having a triangular wave shape in which the waveforms near the maximum value and the minimum value are rounded at a predetermined value at step SP2. That is, assuming that the adjustment is performed so as to have an amplitude between the maximum value 9 [V] and the minimum value 3 [V], the inclination of the straight line portion near the detection point X _A1 of the detection output S _A1 becomes the fourth.
As shown in FIG. 7A, the maximum value 9 [V] and the minimum value 3
It will have a larger value as compared with a triangular waveform with a [V] (hereinafter this is called an ideal triangular wave S _R).

Accordingly, as shown in FIG. 4 (C), the differential waveform DS _A1 of the detection output S _A1 has a square wave shape with a large amplitude,
Variable resistor VR _1A for amplitude adjusting the amplitude of the detection output, the detection point X _A1 near the value d1 of the differential waveform using, as shown in FIG. 4 (D), adjusted to a predetermined value d2 by, as shown in FIG. 4 (E), slope of the linear portion, that thereby the moving speed of Hetsudoamu 4 obtained can be corrected to have a value substantially equal to the ideal triangle waveform S _R.

Further, in step SP6, each detection output S _A , S _B ,
It is determined whether all the differential values of S _C and S _D have been adjusted to the specified values, and if a negative result is obtained (that is, this means that the unadjusted detection outputs S _A , S _B , S _C , and S _D remain. Indicates that it is in use.)
Returning to step SP5, the amplitude of the detection output S _A , S _B , S _C or S _D is adjusted again.

If a positive result is obtained in step SP6, step S
In P7, the processing procedure ends.

According to the speed adjustment method described above, each detection output S _A , S _B ,
The amplitudes of S _C and S _D are referred to the differential waveform, and the detection points X _A ,
X _B, X _C, by the value of the X _D vicinity is adjusted to a predetermined value, the slope of the ideal triangular waveform of the linear portion of the detection outputs
The resulting corrected to almost the same value as S _R, thus, detection outputs
Detection point even if waveform distortion occurs in the output waveform of S _A , S _B , S _C , S _{D
X A, X B, X C} , can effectively remove the moving speed detection error in X _D near.

(G3) Phase difference adjustment method In the position sensor 9 having the above-described configuration, for example, due to an attachment error of the scale 7 or the sensor 8, each detection output S _A ,
S _B, S _C, S detection points _D X _A, X _B, when X _C, X _D is not decreased to the phase difference of 90 ° to each other, performs the Supporting connexion phase difference adjusting the processing procedure shown in FIG. 2 .

That is, the adjuster enters the processing procedure from step SP10, and in steps SP11 and SP12, the detection circuits 13A, 13B, and 13 are detected in the same manner as in the case of the speed adjustment shown in FIG.
Variable resistors VR _1A , VR _1B , VR _1C , VR _1D for amplitude adjustment of C, 13D
By adjusting the variable resistors VR _2A , VR _2B , VR _2C , and VR _2D for voltage adjustment, the maximum and minimum values of the respective detection outputs S _A , S _B , S _C , and S _D are adjusted to specified values. At the same time, a predetermined control current is applied to the voice coil motor 6 to move the head arm 4 at a constant speed.

Followed at step SP13 and step SP14, by measuring the phase difference between the detection outputs _{S A, S B, S C} , detection point X _A of the waveform of _{S D, X B, X C} , X D by an oscilloscope or the like, for example, originally First detection outputs adapted to have a phase difference of 90 ° from each other
S _A and as detection points X _A and X _B1 of the second detection output S _B1 is shown in FIG. 5, the case having a phase difference of 120 ° from one another, for example, a voltage regulating circuit of the second detection circuit 13B 15B variable resistor VR
Adjust _2B lift the second waveform of the detection output S _B1 entirely as indicated by the dotted line of FIG. 5 (B), each of the detection of the first and second detection outputs S _A and S _B2 the phase difference between the points X _a and X _B2 is adjusted to 90 °.

This means that the detection outputs S _A , S _B , S _C , S _D
Detection points in the waveform _{X A, X B, X C} , and that the detection outputs S _A is used _{X D, S B, S C} , even if the waveform distortion S _D, the detection output S _A, S _B , S _C , S _D The straight part in the upper right part itself is about 80%
By selecting the conditions in advance so that a degree of linearity can be guaranteed, the phase difference can be adjusted without changing the voltage level without adversely affecting the speed detection system.

Subsequently, in step SP15, each detection output S _A , S _B ,
S _C, detection point X _A of S _D, X _B, the phase difference of X _C, X _D is determined whether obtained without the 90 ° to each other, if a negative result is obtained, again step SP13 and step SP14 Execute and detect points X _A , X _B , of the respective detection outputs S _A , S _B , S _C , S _{D in} the same manner as described above.
Adjustment is performed so that the phase difference between X _C and X _D becomes 90 ° with each other.

If a positive result is obtained in step SP15,
In the following step SP16, the processing procedure ends.

According to the above-described phase difference adjusting method, each detection output S _A , S _B ,
Focusing on the detection points X _A , X _B , X _C , X _D of S _C , S _D , each detection output
By adjusting the voltages of S _A , S _B , S _C , and S _D , the phase difference of each detection result can be made 90 ° with respect to each other, so that the phase shift can be corrected well and the track margin can be maximized. Can be.

(G4) Other Embodiments (1) In the above-described embodiment, an oscilloscope was used for adjusting the maximum value and the minimum value of each detection output and for adjusting the derivative value. The same effect can be obtained by using the measuring instrument described above.

(2) In the above-described embodiment, the first and second embodiments of the present invention are used in the method of adjusting the position sensor having the four-phase detection output. The present invention can be applied to a method of adjusting a position sensor which is configured to obtain an output.

In particular, the speed adjustment method according to the first aspect of the invention can be applied to a method for adjusting a speed error of a position sensor including only a single-phase detection output.

(3) In the above embodiment, a predetermined control current is applied to the voice coil motor to move the head arm at a constant speed. However, instead of this, the head arm is moved at a constant speed by, for example, an external mechanical operation. The same effect can be obtained even if the user moves with.

(4) In the above-described embodiment, the adjustment method according to the first and second inventions is applied to the position sensor that outputs each detection output having an amplitude of ± 3 [V] around 6 [V]. The first and second inventions are not limited to this, but the point is that a point at which the right-upward or right-downward portion of the triangular-wave-shaped detection output exceeds a predetermined voltage is set as a detection point, and the position is detected using the detection point. This is suitable for application to a position sensor configured to detect a speed using a differential value in the vicinity.

(5) In the above-described embodiment, an embodiment in which the first and second inventions are applied to a method of adjusting a position sensor of a hard disk device has been described. However, the present invention is not limited to this. For example, a machine tool using a motor, etc. The present invention can be widely applied to other position sensor adjustment methods.

H Advantageous Effects of the Invention As described above, according to the present invention, the point at which each of the triangular waveform detection outputs having different phases obtained by the relative movement of the scale and the sensor rises or falls exceeds a predetermined voltage. In a position sensor that associates each recording track with each detection point as a detection point and detects the position of the head based on each detection output corresponding to each recording track, the maximum value and the minimum value of each detection output are set to predetermined values. After adjusting the amplitude of each detection output to a value, the scale and the sensor are moved at a predetermined speed, and each differentiation near each detection point obtained by differentiating each detection output obtained based on the movement result is obtained. By adjusting the amplitude of each detection output so that the value becomes a predetermined value, the inclination at the detection point of each detection output can be adjusted to be constant, so that the speed error can be effectively corrected, Thus, it is possible to realize a method of adjusting the position sensor that can bring the head into the just tracking state.

In addition, when each detection output of a triangular waveform having a different phase obtained by the relative movement of the scale and the sensor rises or falls, a point exceeding a predetermined voltage is set as a detection point, and each recording track is assigned to each detection point. In the position sensor that detects the position of the head based on each detection output corresponding to each recording track, the amplitude of each detection output is adjusted so that the maximum value and the minimum value of each detection output become predetermined values. After that, the scale and the sensor are moved at a predetermined speed, and the voltage of each detection output is adjusted so that the phase difference between the detection points of each detection output obtained based on the movement result becomes the predetermined phase difference. By doing so, the phase difference at each detection point of each detection output can be adjusted, so that the phase shift can be effectively corrected, and thus the head is brought into the just tracking state. Can realize adjustment method of the position sensor that can and.

[Brief description of the drawings]

FIG. 1 is a flowchart showing one embodiment of a speed adjusting method according to the first invention, FIG. 2 is a flowchart showing one embodiment of a position difference adjusting method according to the second invention, and FIG. FIG. 4 is a connection diagram showing a detection circuit, FIG. 4 is a signal waveform diagram for explaining a speed adjusting method of the first invention, FIG. 5 is a signal waveform diagram for explaining a phase difference adjusting method of the second invention, and FIG. FIG. 7 is a schematic plan view of a hard disk device to which the position sensor adjusting method according to the present invention is applied. FIG. 7 is a schematic diagram for explaining the relationship between the scale and the reticle of the position sensor.
The figure is a signal waveform diagram showing a detection output. DESCRIPTION OF SYMBOLS 1 ... Hard disk device, 2 ... Disk 3, ... Head 4, ... Head arm, 5 ... Rotating axis, 6 ... Voice coil motor, 7 ... Scale, 8 ... Sensor, 9 ...
... Position sensor.

Claims (2)

(57) [Claims] A point at which a triangular wave-shaped detection output having a different phase obtained by relative movement of a scale and a sensor rises or falls exceeds a predetermined voltage is set as a detection point. In a position sensor for associating recording tracks and detecting the position of a head based on the respective detection outputs corresponding to the respective recording tracks, the position sensors are arranged so that the maximum value and the minimum value of the respective detection outputs become predetermined values. After adjusting the amplitude and voltage of the detection output, the scale and the sensor are moved at a predetermined speed, and each differential value in the vicinity of each detection point obtained by differentiating each detection output obtained based on the movement result is obtained. A method for adjusting a position sensor, wherein the amplitude of each detection output is adjusted so as to have a predetermined value. 2. When each detection output of a triangular waveform having a different phase obtained by the relative movement of the scale and the sensor rises or falls, a point exceeding a predetermined voltage is set as a detection point, and each detection point is assigned to each detection point. In a position sensor for associating recording tracks and detecting the position of a head based on the respective detection outputs corresponding to the respective recording tracks, the position sensors are arranged so that the maximum value and the minimum value of the respective detection outputs become predetermined values. After adjusting the amplitude and voltage of the detection output, the scale and the sensor are moved at a predetermined speed, and the phase difference between the detection points of the detection outputs obtained based on the movement result is a predetermined phase difference. A method of adjusting a position sensor, wherein the voltage of each of the above detection outputs is adjusted so as to be as follows.