JP2000123510A - Target detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a target detecting device capable of detecting a target accurately and quickly without determining parameters for detecting the target by the experience or by tial-and-error. SOLUTION: This target detecting device is provided with a bi-sected non- contact sensor 31, a beam reflecting part 32 which is provided at a detection object arranged by being opposed to the sensor 31, a straight line part detecting means which extracts an area indicating a prescribed linear characteristic with respect to a signal waveform to be outputted from the non-contact sensor 31 by the reflecting beam from the beam reflecting part 32 and stipulates the linearity measuring range of the non-contact sensor based on the inclination at the time a linear approximation is performed to the area, a monotonic increase detecting means detecting that the signal waveform to be outputted from the non-contact sensor indicates a monotonic increasing property and a zero cross detecting means detecting that the signal waveform includes a zero crossing signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a target detecting device, and more particularly to a target detecting device applied to position control of a servo track writer for writing a servo track on a magnetic disk in a hard disk drive.

[0002]

2. Description of the Related Art Conventionally, a hard disk drive provided with a magnetic disk (also referred to simply as a hard disk or a magnetic disk drive) has been widely used as a storage device of a computer or the like. With the increase in capacity and the reduction in the size of the device, high integration and high recording density of disk devices have become remarkable.

Due to such technical background, a mechanism for accurately positioning a magnetic head when writing a servo track on a magnetic disk has become extremely important. A conventional servo track writing method will be described with reference to the drawings. FIG. 8 is a schematic configuration diagram of a contact type servo track writer (hereinafter abbreviated as STW) device having a mechanism for positioning an arm on the magnetic disk side to an initial position via a push pin (also referred to as a contact pin).

[0004] As shown in FIG.
Broadly, an arm 20 on the magnetic disk side provided with a magnetic head for writing and reading predetermined data to and from the magnetic disk 10 as a storage medium, and a push pin 30 for setting an initial position of the arm 20 on the magnetic disk are extended. And a voice coil motor (VCM) 50 for driving and controlling the position of the STW side arm 40, an encoder 60 for detecting the position of the STW side arm 40, A control unit 70 that performs drive control of the VCM 50 based on the output signal;
Is configured.

In such a contact-type STW device, one end of the magnetic disk-side arm 20 is brought into contact with the push pin 30 set at the initial position, and an initial setting operation for setting the origin is executed. A control method for executing positioning of the disk 10 to a desired track with high accuracy is adopted. By the way, in recent years, with the increase in the capacity of the hard disk device, the positioning accuracy required for the arm is required to be on the order of several μm. On the other hand, the contact type ST employing the push pin as described above
Since the W device has a configuration in which the arm and the push pin are in physical contact with each other, it is easily affected by resonance due to mechanical contact with the push pin. It is pointed out that the positioning control cannot be performed.

In order to solve such a problem, in recent years, hard disk manufacturers have proposed a non-contact type mechanism that does not involve physical contact when setting the initial position of the arm. A configuration example of a non-contact type STW device will be described with reference to the drawings. As shown in FIG. 9, the non-contact type STW device includes a non-contact sensor 31 provided on the STW side arm 40 instead of the push pin 30 shown in FIG. A beam reflector 32 provided on the side arm 20 and a VCM 5 for driving and controlling the position of the magnetic disk side arm 20.
1 and the output signal from the non-contact sensor 31,
And a control unit 71 that controls the driving of the CM 51.

[0007] In the STW device having such a configuration, at the time of initial setting operation, in addition to the STW side arm,
A method of simultaneously controlling the position of the arm on the magnetic disk side is adopted. Specifically, by irradiating the laser beam emitted from the non-contact sensor to the center of the beam reflecting portion provided on the magnetic disk side arm, highly accurate position control is realized. Therefore, prior to the execution of the position control of the magnetic disk side arm, only the STW side arm is moved while monitoring the output signal from the non-contact sensor to accurately specify the center of the beam reflector, that is, the position of the target. Is required.

A specific configuration example of the non-contact sensor and the beam reflecting section will be described with reference to the drawings. It should be noted that the configuration shown in the figure is an example of a good configuration used for position control of the arm on the magnetic disk side, and the configuration based on the combination of the non-contact sensor and the beam reflection unit may be variously modified. Is being considered. As shown in FIG.
A two-part non-contact sensor 31 in which a pair of light receiving elements 31a and 31b are arranged on the lower surface of the side arm 40 in close proximity in a plane.
And a concave mirror 32a provided on the upper surface of the magnetic disk side arm 20. Here, the concave mirror 32a
On the upper surface of the magnetic disk side arm 20, for example, a concave groove having a width of several μm is formed by cutting or the like, and the inside of the groove is mirror-finished.

The displacement detection processing using the non-contact sensor and the beam reflection unit having such a configuration will be described with reference to the drawings. FIG. 11A is a diagram of the two-part non-contact sensor 31 viewed from the concave mirror 32a side.
(B) to (d) are diagrams showing waveforms of output signals A and B indicating the amount of light received by the reflected beam (laser beam) 33 detected by the light receiving elements 31a and 31b constituting the non-contact sensor 31.

When the STW side arm 40 is scanned and reaches the same position as the magnetic disk side arm 20, the concave mirror 32a
As shown in FIG. 11A, the reflected beam 33 is applied across a pair of light receiving elements 31a and 31b, and is output from the light receiving elements 31a and 31b at the center position (target) of the concave mirror 32a. The signals A and B are
As shown in FIG. 11B, a uniform convex waveform is shown.

The signal processing actually performed to detect the target calculates the difference between the output signals A and B, and
A sinusoidal signal waveform as shown in (d) is obtained. This A
The curve near the zero crossing where the -B signal crosses the zero point is
Since linear approximation can be performed, the light receiving elements 31a, 31
b (the light receiving element 31)
a, 31b) are sufficiently large, and FIG.
As shown in (c), A + B which is the sum of output signals A and B
If the (top of) signal is maintained at a constant level, A-
The pseudo linear region near the zero crossing of the B signal can be used as the displacement detection amount.

Here, since the range showing the linear characteristic is limited as described above, in the actual displacement detection processing,
An initial operation for setting a measurement range (range) in which a linear characteristic is obtained in advance is extremely important. Initial operation setting process
The STW side arm is scanned in the time axis direction, and as shown in FIG. 12, the slope dY / of the sinusoidal curve around the linearization region.
A method of comparing dt with preset threshold values -THv and + THv to determine a linearized region is used.

[0013]

However, when the displacement detection processing is actually performed using the non-contact sensor and the beam reflection unit, accurate detection of the target cannot be performed due to the following factors. There is a problem that. Unlike an ideal mirror surface, the concave surface forming the beam reflecting portion has fine irregularities on the surface due to cutting accuracy and the like, so that the reflectance is reduced and it is difficult to distinguish the target from the peripheral region.

Since a ghost waveform is generated in the sensor output signal due to an optical cause such as multiple reflection at a portion near the edge of the concave surface, it is necessary to accurately specify the target only by the intensity of the reflected beam (the amount of received light). Can not. Since the surface of the arm on the magnetic disk side is generally subjected to a surface treatment such as a wiring pattern in addition to the target beam reflecting portion, the intensity of the reflected beam is reduced and, at the same time, the surface includes an uncertain variable element. The target cannot be accurately specified only by the transition state near the zero cross point of the -B signal.

When the laser beam is irradiated to the end of the arm on the magnetic disk side, the end of the beam reflecting portion, the scratch on the surface of the arm, etc., the waveform of the AB signal changes by +/- −, And the servo for controlling the position of the arm is activated, which is an obstacle to the automatic detection of the target. That is, due to the above factors,
As shown in FIG. 13, a plurality of uncertain irregularities are generated in the output signal from the non-contact sensor, and good detection of the target is hindered.

Therefore, with the simple target detection method based on the time change rate of the AB signal (slope of the curve) as described above, accurate detection is difficult, and the time change rate of the AB signal is set as a parameter. In the case of adopting as, because other uncertain factors such as being affected by individual differences of the beam reflecting portion and scanning speed at the time of performing a search operation are also added,
There is a problem that parameter values must be determined by trial and error.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to detect a target with high accuracy and speed without empirically or by trial and error determining parameters for detecting the target. The present invention provides a target detection device capable of performing the following.

[0018]

According to a first aspect of the present invention, there is provided a two-part non-contact sensor in which a pair of light receiving elements are two-dimensionally arranged, and the non-contact sensor. And a beam reflector provided on a detection object disposed opposite to the sensor, and exhibits a predetermined linear characteristic with respect to a signal waveform output from the non-contact sensor by a reflected beam from the beam reflector. It is characterized in that it has a straight-line portion detecting means for extracting a region and defining a linear measurement range of the non-contact sensor based on a slope when the extracted region is linearly approximated.

According to a second aspect of the present invention, in the target detecting apparatus of the first aspect, the linear portion detecting means converts the signal waveform output from the non-contact sensor into a plurality of sections having a predetermined width. The method is characterized in that a straight line is approximated by applying the least squares method for each section, and the section in which the slope of the approximate straight line is maximum is defined in a linear measurement range of the non-contact sensor.

According to a third aspect of the present invention, in the target detecting device of the second aspect, a monotonous detection is performed to detect that a signal waveform output from the non-contact sensor exhibits a monotonic increase over the entire area of the section. It has an increase detecting means, and determines the section detected by the monotonic increase detecting means as a target in a linear measurement range of the non-contact sensor defined by the linear portion detecting means.

According to a fourth aspect of the present invention, in the target detecting device according to the second or third aspect, it is detected that the signal waveform output from the non-contact sensor includes a zero cross point in the section. It has a zero cross detection means, and determines the section detected by the zero cross detection means as a target in a linear measurement range of the non-contact sensor defined by the linear part detection means.

[0022] The invention described in claim 5 is based on claim 1,
5. The target detection device according to 2, 3, or 4, wherein a signal output from the non-contact sensor is defined by a difference between detection signals output from each of the pair of light receiving elements included in the non-contact sensor. It is characterized by being a signal. Further, according to a sixth aspect of the present invention, in the target detection apparatus according to the first, second, third, fourth, or fifth aspect, a predetermined number of samples is set, and the approximate straight line is set for each sampling time corresponding to the number of samples. , The signal waveform monotonically increasing and zero-crossing points, the amount of light received by the non-contact sensor is sampled as a target discrimination index, and based on the target discrimination indexes for the number of samples, the linear portion detecting means, the monotonic The apparatus is characterized in that it has a real-time scanning means for executing a target judgment process in the increase detecting means and the zero-cross detecting means.

According to a seventh aspect of the present invention, in the target detecting apparatus of the sixth aspect, the real-time scanning means is configured to determine an average moving speed of the non-contact sensor with respect to the detection target and a preset sampling period. The number of samples is determined based on the number of samples. That is, the target detection device of the present invention, by having the linear part detection means, divides the target scanning range into a plurality of sections corresponding to the linear characteristic range, and performs a linear approximation by the least square method of the section. The linear measurement range (linear section) of the non-contact sensor can be initialized by using the characteristic that the section where the slope of the approximate straight line is maximum substantially coincides with the linear characteristic range of the non-contact sensor.

The provision of the monotonic increase detecting means makes it possible to determine the section as a target only when the linear section detected by the linear portion detecting means exhibits monotonic increasing property over the entire area. Therefore, it is possible to satisfactorily exclude a pseudo target formed due to the mirror surface state on the detection target side, the reflection state of the beam, and the like, and it is possible to detect a desired target with high accuracy.

The provision of the zero-cross detecting means makes it possible to determine the target section only when the zero-cross point is included in the linear section detected by the linear part detecting means. A desired target can be detected with high accuracy. In particular, the target detection accuracy can be further improved by the combined use with the monotonic increase detection means.

As described above, according to the present invention, the linear signal detecting means, the monotonous increase detecting means, and the zero-cross detecting means are provided, so that the AB signal obtained based on the output signal from the non-contact sensor is provided. Utilizing the characteristic relating to displacement X of the target, predetermined detection conditions (C1 to C4 described later) are defined for the target buried in noise, and the characteristics (linear measurement range and zero crossing) of the non-contact sensor satisfying these conditions are defined. Point) can be initialized.

Therefore, the target can be detected using only the known parameters satisfying the detection conditions. Therefore, as shown in the prior art, the target can be detected without using an empirical or trial-and-error method. The target can be detected with high accuracy. In addition, by having the real-time scanning means, the number n of samples is determined from the average moving speed and the sampling period in accordance with a predetermined conditional expression, and a straight-line slope monotonically increasing index, a zero-cross discrimination index, and a received light quantity discrimination index are determined at each sample time. Calculate,
Using the index values over the past n samples, the linear measurement range and the zero-crossing point can be specified based on the requirement to satisfy the predetermined detection conditions (C1 to C4). This can be performed in real time, and the initial setting can be performed at a higher speed as compared with a method in which the scanning for search and the setting of the initial position are performed by separate operations.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the basic principle of the present invention will be described. The target detection conditions and their parameters defined for realizing the target detection device according to the present invention will be described with reference to the drawings. It should be noted that the target detection device according to the present invention uses the non-contact type S shown in FIG.
It can be realized by the same configuration as the TW device,
In particular, it is characterized by having a straight line portion detecting means, a monotonous increase detecting means, and a zero-cross detecting means for executing the above-described processing.

The target detection conditions applied to the present invention utilize known parameters (P1 to P5) as shown in FIGS. 1A and 1B, which are defined as specifications or characteristics of the non-contact sensor. . P1: threshold value P0 for detecting that the A + B signal calculated based on the output signal from the non-contact sensor maintains a predetermined signal level P2: calculated based on the output signal from the non-contact sensor The slope of the linear (linear) part detected in the AB signal (that is, the sensitivity of the sensor) G0 P3: The variation range σ0 P4 near the slope G0 of the linear part in the AB signal, which is detected in the AB signal The length Xw0 of the linear section (linear measurement range) P5: Noise Yn0 existing in the linear section detected in the AB signal The target detection condition using these parameters is defined as follows. Here, regarding the length Xw0 of the linear section shown in the parameter P4, for example, X
An interval Li slightly smaller than the interval defined by w0 / 2 is set. This corresponds to a section Li for detection (referred to as section length ln) corresponding to the servo range from a range in which linear characteristics determined by the specifications and characteristics of the non-contact sensor are guaranteed.
Means to set.

C1: The signal level of the A + B signal is sufficiently large (greater than the threshold value P0), and the following relationship is established over the entire section Li. P> P0 (1) C2: The gradient Gi of the least-squares approximation straight line of the AB signal in the section Li exists within a predetermined range and satisfies the following relationship.

G 0 (1−σ / 100) <G i <G 0 (1 + σ / 100) (2) C3: The AB signal shows a monotonic increase over the entire section Li. C4: A zero-cross point Zx of the AB signal exists in the section Li. Regarding the determination characteristics when using each of the above detection conditions,
This will be described with reference to the drawings. Here, FIG. 2 shows an A + B signal (light receiving amount) and an AB signal obtained when the non-contact sensor is displaced in the X direction with respect to the concave mirror type beam reflecting portion.
FIG. 3 is a signal diagram obtained by processing based on each signal shown in FIG. 2 so as to correspond to the above-described parameters and detection conditions. Also,
In FIG. 3, the displacement between adjacent sections is δL = 0, and the X-axis of each signal waveform diagram represents the displacement position of the center point of each section Li.

When the detection condition C2 is used for target detection and judgment, as shown in FIG. 3A, the error range within .sigma. (For example, 20%) with respect to the gradient (sensor sensitivity) G0 of the approximate straight line. Since the area that fits is limited to the center of the groove, the target can be reliably detected. on the other hand,
When only the detection condition C1 is used for the detection and determination of the target, a state where the signal level of the A + B signal exceeds the threshold value P0 can be detected, for example, near the center of the groove constituting the concave mirror. However, as shown in FIGS. 2 (a) and 3 (b), similar detection results (A + B signal determination) are obtained not only at the center of the groove but also at the ghost signal generated due to the state of the arm surface or the inside of the groove. In some cases, it may be obtained, and includes an indeterminate element to be independently adopted as a detection condition.

When only the detection condition C3 is used for target detection and determination, it is possible to detect a state where the AB signal monotonically increases over the length ln with respect to the displacement X near the center of the groove. However, as shown in FIG.
A similar detection result (monotonic increase determination) is obtained not only at the center of the groove but also at the ghost signal inside the groove and at the end of the groove.

When only the detection condition C4 is used for the detection and determination of the target, A
A state in which the −B signal transitions from − to + in the direction in which the displacement X increases can be detected. However, as shown in FIG. 3D, a similar detection result (zero-cross determination) can be obtained not only at the center of the groove but also due to a scratch on the arm surface, etc. Elements are included.

Therefore, in the present invention, known parameters defined as specifications or characteristics of the non-contact sensor are used, and the above-mentioned condition C2 is required as a target detection condition, and other conditions C1, C3, C
By appropriately combining the four, the target can be accurately detected without using an empirical or trial-and-error method as in the conventional detection method.

[0036]

Next, a first embodiment of the target detecting apparatus according to the present invention will be described with reference to the drawings. The target detection device of the present embodiment is configured to include a linear portion detection unit, a monotone increase detection unit, and a zero-cross detection unit in order to execute a target detection process.

First, prior to describing each configuration, FIG.
As shown in (a), the target image is divided into sections Li set in association with the length Xw0 over the target scanning range, and among the sections Li (i = 1, 2, 3,...), The section Lz where all of the detected conditions C1 to C4 are satisfied is regarded as a target (linearization range) satisfying the specification of the non-contact sensor shown in FIG. 1, and the zero cross point Zx in the section Lz is determined as the neutral point of the displacement 0. To be defined. Here, FIG.
FIG. 3 is a diagram showing a signal waveform of an AB signal around a target and a method of dividing a section.

(Linear part detecting means) Next, the processing concept of the linear part detecting means applied to this embodiment will be described with reference to FIG.
This will be described with reference to FIG. FIG. 4B is a diagram corresponding to the signal waveform shown in FIG. 4A and showing the slope of the approximate straight line for each section Li.

The linear portion detecting means is a structure for determining the above-mentioned detection condition C2. As shown in FIGS. 4 (a) and 4 (b), the linear portion detecting means has a length shifted by an appropriate width δL in the position X direction. Is set to Xw0 or a section Li having a length corresponding to Xw0, and the slope when a straight line is approximated using the least squares method for each section Li
(Indicated by a dashed line in FIG. 4A). Each section Li
The midpoint _{m i (i = 1,2,3, ··} ) is plotted linear gradient G (Li) obtained for, in linearizable section A-B signal (FIG. 4 (b), L3 (Corresponding to .about.L4) and a region falling within a predetermined range [Gw0-.sigma.0, Gw0 + .sigma.0] defined in the specification of the non-contact sensor is determined.

In the example shown in FIG. 4, since the section Li and the linearizable section are shifted and a linearizable section exists between the sections L3 and L4, the slopes G (L3) and G (L4) are true. The maximum value can be obtained with high accuracy by setting δL sufficiently small. FIG.
In (b), the broken line Cg indicates a continuous curve when δL is set to infinity.

(Monotone increase detection means) Next, the processing concept of the monotone increase detection means applied to this embodiment will be described.
This will be described with reference to FIG. Depending on the setting condition of the section Li described above, even if the actual gradient G (Li) is much larger than the predetermined gradient Gw0, G
If (Li) is close to Gw0, it may be regarded as a linearizable section.

Therefore, as shown in FIG. 5, the monotonic increase (dY / dX> 0) of the signal waveform of the AB signal is examined, and when the monotonic increase is observed in the entire section Li, Li is targeted. Judge. That is, the monotonous increase detecting means determines the detection condition C3. In the example shown in FIG.
Since there is a region in i that is not determined to be monotonically increasing, it is excluded from the target targets.

(Zero Cross Detection Means) Next, the processing concept of the zero cross detection means applied to this embodiment will be described with reference to FIG. As mentioned above, AB
Focusing only on the slope component of the signal waveform of the signal, the section Li
May be considered as a linearizable section.

Therefore, as shown in FIG. 6, the AB signal transitions from "-" to "+" in the increasing direction of the X axis, or the AB signal transitions from "+" to "-". The zero cross point to be performed is checked, and if a zero cross point exists in the section Li, Li is determined to be the target. In the example shown in FIG. 6, since the zero cross point Zx exists in the area outside the section Li, it is excluded from the target.

By appropriately combining the above detection means,
Any one of the detection conditions C2 and C1, C3, C4, or a section satisfying all the conditions can be determined as the target. In particular, since a section satisfying all of the detection conditions C1 to C4 exists only in the center of the groove (beam reflection section), X = X as a zero cross point (servo neutral point).
t can be specified to only one point.

Therefore, such detection conditions C1 to C
By employing the detecting means having the position 4, the information on the detected position Xt in the X direction can be given to the control unit for the STW side arm shown in FIG. 9, and the STW side arm is moved to the position Xt. The position at which the laser beam is irradiated to the center of the groove can be controlled with high precision. By giving an instruction to the control unit on the magnetic disk side, the servo is locked at the neutral point of the servo, and the non-contact type STW device Initial operation settings can be made.

Next, a second embodiment of the target detecting apparatus according to the present invention will be described with reference to the drawings. This embodiment is characterized in that it has a real-time scanning means for executing the target detection processing shown in the above-described embodiment in real time during one search operation.

In order to execute the above-described target detection processing in real time during one search operation, the current time t
_{For k} , if all of the following conditional expressions hold, then Zj =
The position _Xj that is 1 is determined to be the neutral point of the target. C11: ΠPj = 1 (11) C12: G0 (1-σ / 100) <Gk <G0 (1 + σ / 100) (12) C13: ΠMj = 1 (13) C14: ΣZj = 1 (14) Here, each parameter is as follows.

P11: slope of straight line: Gk P12: monotone increasing index: Mj (j = k,..., K-n + 1) P13: zero-cross discriminating index: Zj (j = k,. n +
1) P14: Light reception amount discrimination index: Pj (j = k,..., K-n + 1) Further, Π is a symbol for cumulatively multiplying j = k,. Σ is j = k,..., Kn
+1 is a symbol for cumulative addition.

Next, parameters P11 to P14 (slope of a straight line, a monotone increase index, a zero-cross index, a light-receiving amount determination index) defined in this embodiment will be described with reference to FIG. (Line inclination calculation processing) As shown in FIG. 7, the position X at each sample time t _j and the sensor output Y (AB signal)
_Are set to X _j and Y _j, and a set of a total of n sample data is stored retroactively from the current time t _j = t _k, and the slope Gk of the straight line is calculated based on the set.

The total n pieces of sample data are represented by the following combinations. ｛(X _k , Y _k ), (X _k−1 , Y _k−1 ),... (X _{k−n + 1} ,
Y _{k−n + 1} )｝ Then, an equation for calculating the gradient G _{k of} the straight line is expressed as follows. G _k = Σ (X _j −mean (X _k )) (Y _j −mean (Y _k )) / Σ (X _j −mean (X _k )) ² (21) where mean (X _k ) = ΣX _j , mean (Y _k ) = ΣY _j . As described above, Σ is cumulatively added for j = k,..., K−n + 1.

Further, the number n of the sample data is set as follows. n = Xw0 / (Vm · Ts) (22) Here, Vm is an average moving speed in the X direction, and Ts is a sampling period. (Monotone increase discrimination processing) When the position (scan displacement) X and the AB signal (signal level) Y satisfy the following expression, the monotone increase index Mj is set to 1; otherwise, Mj is set to Mj.
= 0, and stores the monotone increasing index Mj (j = k,..., K-n + 1) going back to the past n samples.

Sign (X _j −X _j−1 ) · (Y _j −Y _j−1 ) + Y _n0 > 0 (23) (Zero crossing discrimination processing) Position (scan displacement) X and AB signal ( If the signal level) Y satisfies the following equation, the zero-crossing discrimination index Zj is set to 1, and in other cases, Zj = 0 is defined, and the zero-crossing discrimination index Zj is traced back to the past n samples.
(J = k,..., K−n + 1) are stored.

Sign (Y _j−1 ) · sign (jk) <0 and (24) sign (X _j −X _j−1 ) · sign (Y _j −Y _j−1 )> 0 (light receiving amount Discrimination processing) When the A + B signal (signal level) P satisfies the following equation, the received light amount discrimination index Pj = 1, otherwise, Pj = 0 is specified, and the received light discrimination index retroactive to the past n samples Pj (j = k,..., K-n + 1) is stored.

P> P0 (25) As described above, in addition to the configuration of the target detection device shown in the first embodiment, by employing the real-time scanning means having the processing method described above, the average The number of samples to be stored retrospectively is determined based on the moving speed and the sampling cycle, and the slope of the straight line, the monotone increasing index, the zero-crossing determining index, and the light receiving amount determining index are processed and determined at each sample time, and during the search operation. Target detection can be performed in real time.

In this embodiment, the configuration applied to the positioning control of the arm of the STW device has been described, but the present invention is not limited to this embodiment. In short, it goes without saying that the present invention can be favorably applied to any position detecting mechanism having a combination of a non-contact sensor and a beam reflecting section. The configuration of the non-contact sensor and the beam reflection unit to which the present invention is applied is 2
Although the combination of the split type non-contact sensor and concave mirror was shown,
The applicable range of the present invention is not limited to this configuration.

In short, as long as the output signal characteristics as shown in FIG. 11 can be obtained, the configuration of the beam reflecting portion is not limited to the above-described concave mirror shape, but may be a convex mirror shape. It is needless to say that a cylindrical mirror member or the like may be fixed.

[0058]

As described above, according to the present invention,
A target buried in noise by using a characteristic relating to a displacement X of an AB signal obtained based on an output signal from a non-contact sensor by including a linear portion detecting unit, a monotonic increase detecting unit, and a zero cross detecting unit. , Predetermined detection conditions (C1 to C4 to be described later) are defined, and the characteristics (linear measurement range and zero-cross point) of the non-contact sensor satisfying these conditions can be initialized.

Therefore, the target can be detected using only the known parameters that satisfy the detection condition. Therefore, as shown in the prior art, the target can be detected without using an empirical or trial-and-error method. The target can be detected with high accuracy. In addition, by providing the real-time scanning means, the number n of samples is determined from the average moving speed and the sampling period in accordance with a predetermined conditional expression, and a straight-line slope monotone increasing index, a zero-crossing determining index, and a light receiving amount determining index are determined at each sampling time. Is calculated, and the linear measurement range and the zero-cross point can be specified based on the requirement to satisfy the predetermined detection conditions (C1 to C4) using the index values over the past n samples.

Therefore, the target can be detected in real time during one scanning operation, and the initial scanning can be performed at a higher speed as compared with a method in which the scanning for search and the setting of the initial position are executed by individual operations. Settings can be made.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing parameters of a non-contact sensor applied to a target detection device according to the present invention.

FIG. 2 is a conceptual diagram (part 1) illustrating a basic principle of target detection processing.

FIG. 3 is a conceptual diagram (part 2) illustrating the basic principle of target detection processing.

FIG. 4 is a diagram illustrating a processing concept of a straight line portion detection unit applied to the target detection device according to the present invention.

FIG. 5 is a diagram showing a processing concept of a monotonous increase detection means applied to the target detection device according to the present invention.

FIG. 6 is a diagram showing a processing concept of a zero-cross detecting means applied to the target detecting device according to the present invention.

FIG. 7 is a diagram illustrating a processing concept of a real-time scanning unit applied to the target detection device according to the present invention.

FIG. 8 is a schematic configuration diagram of a conventional contact STW device.

FIG. 9 is a schematic configuration diagram of a conventional non-contact type STW device.

FIG. 10 is a diagram illustrating a specific configuration example of a non-contact sensor and a beam reflecting unit.

FIG. 11 is a conceptual diagram of a displacement detection process.

FIG. 12 is a diagram illustrating a method for determining a linearized region.

FIG. 13 is a diagram for explaining a problem of the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Magnetic disk 20 Magnetic disk side arm 30 Push pin 31 Non-contact sensor 31a, 31b Light receiving element 32 Beam reflection part 32a Concave mirror 33 Reflection beam 40 STW side arm 50 VCM 60 Encoder 70, 71 VCM control part

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 2F065 AA02 AA22 AA31 AA39 BB03 BB24 BB25 CC03 DD03 DD06 FF66 GG04 HH04 JJ03 JJ23 JJ26 LL19 QQ08 QQ23 QQ25 QQ27 QQ29 QQ42 2F112 AA07 BA05 FA06 DA09 FA09 DA09 FA09 DA09 FA09 DA09 FA09

Claims (7)

[Claims] 1. A two-dimensional arrangement in which a pair of light receiving elements are two-dimensionally arranged.
A signal output from the non-contact sensor by a split-type non-contact sensor and a beam reflection unit provided on a detection object arranged to face the non-contact sensor, and a reflected beam from the beam reflection unit It has a linear part detecting means for extracting a region showing a predetermined linear characteristic with respect to the waveform, and defining a linear measurement range of the non-contact sensor based on a slope when the extracted region is linearly approximated. Target detection device. 2. The linear part detecting means divides a signal waveform output from the non-contact sensor into a plurality of sections having a predetermined width, applies a least square method to each of the sections, and approximates a straight line, 2. The target detecting apparatus according to claim 1, wherein the section in which the slope of the approximate straight line is maximum is defined in a linear measurement range of the non-contact sensor. 3. A monotonic increase detecting means for detecting that a signal waveform outputted from said non-contact sensor shows monotonic increasing property in the entire area of said section, wherein said non-contact signal defined by said linear part detecting means is provided. 3. The target detection device according to claim 2, wherein the section detected by the monotonic increase detection means in the linear measurement range of the contact sensor is determined as a target. 4. A non-contact sensor defined by said linear portion detecting means, comprising: zero-cross detection means for detecting that a signal waveform output from said non-contact sensor includes a zero-cross point in said section. 4. The target detecting device according to claim 2, wherein the section detected by the zero-cross detecting means in the linear measurement range is determined as a target. 5. A signal output from the non-contact sensor,
The target detection device according to claim 1, wherein the target detection device is a signal defined by a difference between detection signals output from each of the pair of light receiving elements constituting the non-contact sensor. 6. A predetermined number of samples is set, and at each sampling time corresponding to the number of samples, the slope of the approximate straight line, monotonic increase and zero-cross point of the signal waveform, and the amount of received light in the non-contact sensor are set as targets. Sampling as a discrimination index, and based on the target discrimination index for the number of samples, real-time scanning means for executing a target judgment process in the linear portion detection means, the monotone increase detection means and the zero-cross detection means. The target detection apparatus according to claim 1, 2, 3, 4, or 5, wherein 7. The real-time scanning unit according to claim 6, wherein the number of samples is determined based on an average moving speed of the non-contact sensor with respect to the detection target and a preset sampling period. Target detection device.