JP2018096876A - Shape estimation method, steel sheet shape correction method, and manufacturing method of steel sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shape estimation method, a steel sheet shape correction method, and a manufacturing method of a steel sheet capable of properly estimating the shape by suppressing a difference between balance gaps at a measurement end part of the shape estimation object.SOLUTION: A shape evaluation method is configured such that, when the shape evaluation of a shape measurement surface of a shape evaluation object is performed using a calculator having arithmetic processing functions, the balance of a predetermined length is allotted with a shape measurement surface of the shape estimation object, and a phase correction band-pass filter having a frequency response characteristic when measuring a gap between the balance and the shape measurement surface is caused to act on a point group data at a position of a measurement point on the shape measurement surface of the shape estimation object, thereby obtaining the gap. Particularly, the gap between the balance at the sheet end and the shape measurement surface can be correctly obtained by elongating projective coordinates by setting, for example, an inverse of elongation in the adjustment area from at least one measurement end of the shape estimation object to the predetermined inner side.SELECTED DRAWING: Figure 13

Description

  The present invention relates to, for example, a shape evaluation method for a shape evaluation object such as a steel plate, a shape correction method for a steel plate, and a method for manufacturing a steel plate, for example, a shape such as warpage, ear wave, distortion, etc. Is suitable for correcting the side of the rolling line.

  As a shape evaluation method of a shape evaluation object such as a steel plate, for example, as described in Patent Document 1 below, a predetermined length of difference is applied to the shape measurement surface of the shape evaluation object, and the difference and shape side Using a band-pass filter that has frequency response characteristics when measuring the gap between the measurement surface and the fixed surface, the band-pass filter is applied to the point cloud data at the position of the measurement point on the shape measurement surface of the object to be evaluated. There is something to ask for.

JP 2014-104483 A

In the shape evaluation method as in Patent Document 1, an operator (operator) applies a difference of a preset length on the surface of the steel sheet, and recognizes the shape of the steel sheet by observing a gap between the difference and the steel sheet. The shape evaluation equivalent to the case can be performed accurately in a short time.
However, when the operator actually places the difference on the steel plate surface, the difference gap is constrained to zero at the tip and tail ends of the steel plate. That is, as shown in FIG. 12, the difference effective length of the difference gap becomes short near the end of the steel plate or the tail end, and the difference gap becomes zero in principle at the plate end. It is necessary to shorten the difference length in accordance with the reduction of the difference effective length in the vicinity of the end, but when acting as a bandpass filter, the difference length cannot be changed for each place.

Therefore, when the difference gap is measured by a calculation process using a bandpass filter, for example, as shown in FIG. 10, the difference gap between the tip and tail ends of the steel sheet is not zero, and a relatively large value. Therefore, there is an unsolved problem that the error of the difference gap becomes larger than when the operator actually applies the difference to the end of the steel plate.
The present invention has been made paying attention to the above-described unsolved problems, and can appropriately evaluate the shape by suppressing the error of the difference gap at the measurement end of the shape evaluation object, Accordingly, it is an object of the present invention to provide a shape evaluation method, a steel plate shape correction method, and a steel plate manufacturing method capable of appropriately correcting the shape of a shape evaluation object.

  In order to solve the above-described problems, the shape evaluation method according to the present invention uses a calculator having a calculation processing function to calculate a shape length of a shape measuring surface of a target object for shape evaluation using a predetermined length difference. A phase compensation bandpass filter having a frequency response characteristic when measuring the gap between the difference metal and the shape measurement surface is applied to the shape measurement surface of the shape evaluation object on the shape measurement surface of the shape evaluation object. A shape evaluation method for obtaining the gap by acting on point cloud data at the position of the measurement point, wherein projective coordinates are extended in an adjustment area from at least one measurement end of the shape evaluation object to a predetermined length inside. I am doing so.

In the steel plate shape correction method according to the present invention, when the shape evaluation object is a steel plate, a position where the absolute value of the gap obtained by the shape evaluation method is equal to or more than a predetermined value set in advance is determined. It is presented as a press correction position.
Moreover, the steel plate manufacturing method which concerns on this invention uses the said steel plate shape correction method for a steel plate manufacturing process.

  According to one aspect of the shape evaluation method according to the present invention, the projection coordinates are extended in the adjustment region on the end side of the shape evaluation object, and then the phase compensation data is applied to the point cloud data at the position of the measurement point on the shape measurement surface. A band pass filter is activated. For this reason, by extending the projection coordinates in the adjustment region, it is possible to accurately evaluate the difference gap at the measurement end portion of the evaluation object by relatively shortening the difference length.

Moreover, the shape evaluation object is a steel plate, and the position where the absolute value of the gap between the difference obtained by the shape evaluation method and the shape measurement surface is equal to or greater than a preset specified value is presented as the press correction position by the pressure ram. To do. Thereby, a steel plate shape can be corrected appropriately.
Furthermore, the steel plate which correct | amended the steel plate shape correctly can be manufactured by using a steel plate shape correction method for a steel plate manufacturing process.

It is a top view which shows one Embodiment of schematic structure of the steel plate shape correction apparatus to which the shape evaluation method and steel plate shape correction method of this invention are applied. It is a schematic block diagram of the laser irradiation apparatus which comprises the laser distance meter in the shape measuring apparatus of FIG. It is a flowchart which shows the arithmetic processing for the steel plate shape correction performed within the control apparatus of FIG. It is explanatory drawing which shows an example of point cloud data. It is a schematic diagram of a difference clearance measurement model. It is a wavelength response characteristic figure of a frequency response function of a difference crevice measurement model. It is explanatory drawing of the wavelength characteristic in the case of calculating | requiring a difference gap from the difference of the curved surface from which a frequency characteristic differs. 5 is a height curved surface obtained by smoothing spline processing for removing measurement errors from the point cloud height data of FIG. It is explanatory drawing of the difference | interval gap calculated | required from the difference of the curved surface from which a frequency characteristic differs using the smoothing spline curved surface of FIG. FIG. 10 is a side view of the difference gap in FIG. 9. FIG. 10 is a top view of the difference gap in FIG. 9. It is explanatory drawing which shows the difference measuring method in a board end. It is a characteristic diagram showing the reciprocal number of an expansion rate. It is a flowchart which shows an example of the filter processing procedure performed with a shape measuring apparatus. FIG. 15 is an explanatory diagram of a difference gap similar to FIG. 10 showing a result of performing the process of FIG. 14. It is explanatory drawing of the shape evaluation method which calculates | requires a difference | clearance clearance gap from the difference of the curved surface from which frequency characteristics differ.

It is explanatory drawing of the difference | interval gap calculated | required by calculation according to the shape evaluation method of FIG. It is a correlation diagram of the difference | interval gap calculated | required by calculation, and the difference | interval gap measured by the operator.

Hereinafter, a steel plate shape correction apparatus to which a shape evaluation method and a steel plate shape correction method according to an embodiment of the present invention are applied will be described with reference to the drawings.
FIG. 1 is a plan view showing a schematic configuration of the steel sheet shape correcting device of the present embodiment. This steel plate shape correction apparatus corrects the shape of the steel plate S offline. Reference numeral 1 in the drawing denotes a press machine that corrects the shape of the steel sheet S. An entrance bed 3 is disposed on the entry side of the press machine 1, and an exit bed 4 is disposed on the exit side of the press machine 1. .

  Each of the beds 3 and 4 is provided with a large number of rollers for transporting the steel sheet S, and the transport state of the steel sheet S can be controlled by controlling the rotation state of the rollers. In addition, a position detection device 7 that detects the position of the steel sheet S is provided on the sides of the entrance bed 3 and the exit bed 4. The position detection device 7 scans the laser beam in the conveyance direction of the steel plate S to measure the shape in the conveyance direction of the steel plate S, as in the shape measurement device described later, and from which position the steel plate S is located based on the shape measurement result. To detect.

In the case of the press machine 1 of the present embodiment, the steel plate S is pressurized from above with the pressurizing ram 2 and a bending moment (three-point bending) is mainly applied to the steel plate S to correct the shape of the steel plate. The shape of the steel plate S is measured by a steel plate shape measuring device described later.
Parameters for correcting the shape of the steel sheet include, for example, a differential gap obtained from the shape of the steel sheet S, a pressure applied by the pressure ram 2, a position and interval of a floor plate called a shim, a position of the steel sheet S, that is, Examples include a transport state.

  In the steel plate shape correction by the press machine 1 of the present embodiment, the steel plate S is pressed with the pressure ram 2 using a shim, as will be described later. For example, when the steel plate S mounted on the press machine 1 is bent upwardly, two shims are laid under the steel plate S sandwiching the convex portion, and the convex portion between the shims is pressed with the pressure ram 2. Pressurize with. On the other hand, for example, when the steel sheet S is bent downward, a single shim is laid under the convex part, and the shim is interposed on both sides of the steel sheet S sandwiching the convex part. Press.

The bending moment due to the pressure ram 2 is mainly generated only in the steel sheet S in the portion between the shims. The above-described various parameters are adjusted in consideration of the deformation amount of the steel sheet S due to this bending moment and the return amount when pressure is released, the so-called springback amount.
A shape measuring device 5 was installed on the entry side of the entry bed 3 and the exit side of the exit bed 4, and a control device 6 was installed on the side of the exit bed 4. Among these, the shape measuring device 5 includes a laser distance meter that detects the distance to the detection point with a laser beam, and a computer system that measures the shape of the steel sheet S from the distance data detected by the laser distance meter. .

  The concrete steel plate shape measuring method of the shape measuring apparatus 5 is the same as that described in Japanese Patent Application Laid-Open No. 2010-155272 previously proposed by the present applicant. That is, the shape measuring apparatus 5 of the present embodiment includes a laser rangefinder that measures the distance by scanning the laser beam three-dimensionally. The steel sheet S is generally long in the transport direction and short in the direction orthogonal to the transport direction. That is, the steel sheet S has a long side and a short side, and in the present embodiment, the long side direction is defined as the longitudinal direction (also referred to as the x direction), and the short side direction is defined as the width direction (also referred to as the y direction). The height direction is also referred to as the z direction.

As shown in FIG. 2, the laser distance meter of the present embodiment has a laser light source 11 mounted on a turntable 12, and a known galvanometer mirror 13 is disposed at the laser emission port of the laser light source 11. The rotation axis of the galvanometer mirror 13 coincides with the laser beam from the laser emission port of the laser light source 11, and the rotation axis of the galvanometer mirror 13 is orthogonal to the rotation axis of the turntable 12.
In this embodiment, by rotating the galvanometer mirror 13, the laser light from the laser light source 11 is polarized in the longitudinal direction of the steel sheet S, that is, in the conveying direction of the steel sheet S in FIG. 1, and the turntable 12 is rotated. Thus, the laser beam polarized from the galvanometer mirror 13 is scanned mainly in the width direction of the steel sheet S, that is, in the direction orthogonal to the conveying direction of the steel sheet S in FIG. Therefore, for example, by receiving retroreflected light of laser light emitted toward the surface of the steel sheet S, the distance to the measurement point on the surface can be obtained. This distance can be converted into position information in the height direction (z direction) including an error if the position in the longitudinal direction (x direction) and the position in the width direction (y direction) of the measurement point are defined. Accordingly, when the surface of the steel sheet S is the shape measurement surface, the height (z) position on the x and y coordinates on the shape measurement surface can be recognized as the shape of the shape measurement surface.

In addition, the shape measuring apparatus 5 of this embodiment can measure the shape of the steel sheet S not only on the entry bed 3 and the exit bed 4 but also under the pressurization ram 2 of the press 1. Further, the position detection device 7 similarly detects the shape of the steel sheet S, and detects the position of the steel sheet S depending on where the shape is.
Furthermore, the shape measuring device 5 is not limited to performing shape measurement in a state where conveyance of the steel sheet S is stopped. For example, by scanning the laser beam in the width direction while conveying the steel sheet S in the longitudinal direction, x, You may make it recognize the height (z) position on ay coordinate as a shape of a shape measurement surface.

  The control device 6 is constructed with a computer system such as a host computer, and the shape measuring device 5 performs the shape evaluation of the surface of the steel sheet S, that is, the shape measuring surface, and controls the operating state of the press machine 1 and the beds 3 and 4. Then, the shape correction of the steel sheet S is performed. As shown in FIG. 3, this calculation process is performed simultaneously with, for example, a steel plate shape correction start command. First, in step S <b> 1, the steel plate S is moved to the pressurization ram 2 of the press 1 by the entrance bed 3 and the exit bed 4. Bring it down. Next, it transfers to step S2 and the shape evaluation of the surface which is a shape measurement surface of the steel plate S is performed by the said shape measuring apparatus 5. FIG. Next, the process proceeds to step S3, and the shape correction control of the steel sheet S is performed by controlling the operating state of the press machine 1 and the beds 3 and 4 based on the shape evaluation of the steel sheet S obtained in the step S2. Next, it transfers to step S4 and it determines with the shape correction of the steel plate S having been completed. Next, the process proceeds to step S5, where the steel sheet S is discharged from below the pressurization ram 2 by the entry side bed 3 and the exit side bed 4, and the control is finished.

  Next, a shape measuring surface of the steel sheet S by the shape measuring device 5, that is, a surface shape evaluation method will be described. In the shape measuring device 5, for example, point cloud data of position data as shown in FIG. 4 can be acquired by emitting and receiving the laser beam described above. The position data has a longitudinal direction (x direction) and a width direction (y direction) defined, and has an error in the height direction (z direction). For such point cloud data, for example, the smoothed spline curved surface described in JP 2012-37313 A previously proposed by the present applicant can be applied.

The smoothed spline curved surface is a spline-shaped curved surface obtained by smoothing the point cloud data with the spline degree l and the smoothing parameter γ, and the frequency response function h (ω ₁ , ω ₂ ) is expressed by the following equation (1). The

In formula (1), ω ₁ is an angular frequency corresponding to the longitudinal direction (not necessarily coincident with the longitudinal direction of the steel sheet S), and ω ₂ is an angle corresponding to the width direction (not necessarily coincident with the width direction of the steel sheet S). Is the frequency. From equation (1), it can be seen that the smoothed spline curved surface functions as a phase compensation low-pass filter.
Consider using the smoothed spline curved surface to evaluate the shape with a difference. The difference of the difference is evaluated only in the direction of the difference, and when the difference is considered as the longitudinal direction, the width direction perpendicular to the longitudinal direction is not evaluated. Further, the difference clearance estimation method is considered with the spline order l being 1.

The frequency response function h (ω ₁ , ω ₂ ) is a low-pass filter when the difference length is L when the smoothing parameter γ is the above equation (1). The difference between the output of the low-pass filter having the difference length, that is, the smoothed spline curved surface and the smoothed spline curved surface represented by the above formula (1) is the output of the bandpass filter. For example, a relatively short difference length L _H for blocking the error of the point cloud data, that is, a difference having a difference length L _H shorter than the difference length L is considered, and smoothing by the difference of the difference length L _H is performed. A difference gap is obtained by subtracting the smoothed spline curved surface with the difference of the difference length L represented by the above formula (1) from the spline curved surface. Assuming that the frequency response function of the difference gap is f ₁ (ω ₁ , ω ₂ ), the frequency response function f ₁ (ω ₁ , ω ₂ ) is expressed by the following equation (2). The frequency response function h (ω ₁ , ω ₂ ) of the smoothed spline curved surface represented by the above formula (1) is a low-pass filter when the difference length is L, and therefore this frequency response function h (ω _If the angular frequency ω ₁ in the longitudinal direction of ( ₁ , ω ₂ ) is multiplied by L _H / L, a frequency response function of the smoothed spline curved surface by the difference of the difference length L _H can be obtained.

When the formula (2) is expanded, the following formula (3) is obtained.

この式（４）の周波数応答関数ｆ_１（ω_１，０）は、位相補償バンドパスフィルタである。上記の演算は、任意のスプライン次数に対して一般化は可能である。 When the angular frequency ω ₂ in the width direction is ignored in this formula (3) and ω ₂ = 0, the following formula (4) is obtained.

The frequency response function f ₁ (ω ₁ , 0) of the equation (4) is a phase compensation band pass filter. The above operations can be generalized for any spline order.

The frequency response when measuring the difference gap by applying the difference length L (difference length) to the surface of the steel sheet S (shape measuring surface), that is, the smoothed spline curved surface. The function can be considered to have a maximum gain of 2 when the resonance frequency is 2π / L. That is, when y (x) is the deflection of the steel sheet, Y (x) is the difference gap measurement value, and L is the difference length, the following expression (5) is established from the schematic diagram of the difference gap measurement model in FIG. .

This formula (5) is Laplace transformed to obtain the following formula (6).

更に、差金隙間測定値の伝達関数Ｇ（ｓ）の周波数応答関数Ｇ（ω）は下記式（８）で表される。 From the equation (6), the transfer function G (s) of the difference gap measurement value is represented by the following equation (7).

Further, the frequency response function G (ω) of the transfer function G (s) of the difference gap measurement value is expressed by the following equation (8).

FIG. 6 shows the wavelength response characteristics of the frequency response function G (ω) of the differential gap measurement value expressed by the above equation (8). In this model, the gain is jagged in the region where the wavelength is short. Since the operator intends to measure the short wavelength irregularities with a shorter length difference, this portion can be ignored. Therefore, the resonance frequency ω ₀ of the frequency response function of the equation (8) is expressed by the following equation (9), and the maximum gain at the resonance frequency ω ₀ is expressed by the following equation (10).

  Therefore, the frequency response function when the operator measures the difference gap is considered to have a maximum gain of 2 when the resonance frequency is 2π / L. In order to match the frequency response function of the difference gap and the frequency response function when measuring the difference gap to the steel sheet surface as much as possible, the resonance frequency and the maximum gain should be matched. .

FIG. 7 shows the wavelength response characteristics of the frequency response function f ₁ (ω ₁ , ω ₂ ) of the difference gap obtained from the difference between the two smoothed spline curved surfaces. Here, the calculation was made assuming that the difference length L was 2 m, the difference length L _H for blocking the error was 0.2 m, and the smoothing parameter was 0.19 m ⁴ . The frequency response function f ₁ (ω ₁ , ω ₂ ) when the difference gap is obtained from the difference between the two smoothed spline curved surfaces has a large gain in the wavelength range of 0.2 m to ₂ m. Wide filter bandwidth. That is, by obtaining the difference gap from the difference between the two smoothed spline curved surfaces, it is possible to recognize (evaluate) a sharper (fine) unevenness (deformation).

The shape correction apparatus that mainly corrects the shape by conveying the steel sheet S in the longitudinal direction has a characteristic that the longitudinal direction of the steel sheet S can be corrected to a finer deformation.
By the way, the shape measuring apparatus 5 can acquire point cloud data of position data as shown in FIG. 4, for example, by the above-described emission / light reception of the laser beam. The position data has a longitudinal direction (x direction) and a width direction (y direction) defined, and has an error in the height direction (z direction).

A steel plate shape obtained by smoothing the point cloud data with a low-pass filter frequency response function is as shown in FIG. Here, the error cutoff wavelength was set to 0.25 m. It can be seen from FIG. 8 that the “unevenness” of the measurement error component has been removed.
The point cloud data in FIG. 4 is estimated with the frequency response function of the bandpass filter f1 (high frequency error cutoff wavelength 0.25 m, low frequency cutoff wavelength (difference length) 2.0 m), and the gray scale processed difference gap is illustrated. 9 and FIG. The positive value of the difference gap indicates concave, and the negative value indicates convex.

  The difference gap in FIG. 10 represents the difference gap in FIG. 8 from a viewpoint parallel to the surface of the steel plate, and positive values are convex, that is, convex upward, negative values are concave, that is, convex downward. Yes. The difference gap is easy to recognize the unevenness (deformation) of the surface (shape measurement surface) of the steel sheet as a whole, but it is difficult for the operator to know which part should be pressed and to what extent. Therefore, FIG. 11 shows the difference gap in FIG. 10 in a planar shape in the longitudinal direction and the width direction. In this way, it can be understood that the portions where the absolute value of the difference gap is equal to or larger than a predetermined value set in advance, for example, are expressed whitish or blackish, and these portions may be press-corrected.

About convex shape, two shims are spread under the steel plate which pinched the above convex parts, and the convex part between the shims is pressurized with a pressure ram. As for the concave shape, one shim is laid under the concave portion, and the shim is interposed on both sides of the steel plate sandwiching the concave portion, and the pressure is applied with a pressure ram.
By the way, in FIG. 10, the difference gap is a relatively large value at the front end and the rear end of the plate, but in reality, it must be constrained to zero. As shown in FIG. 12, the difference effective length of the difference gap is shortened in the vicinity of the plate end, and the difference between the differences is theoretically zero at the plate end.

  Therefore, in the vicinity of the plate edge, it is necessary to sequentially shorten the difference length in order to match the gap measurement value of the operator. However, when the band-pass filter is applied, the difference length cannot be changed for each location of the steel plate S. Then, conversely, by extending the projection plane having the longitudinal position and width as components in the longitudinal direction, the difference length for each location of the steel sheet S can be relatively changed.

For this purpose, when x is the longitudinal coordinate on the shape measuring surface of the steel sheet S before stretching, X is the longitudinal coordinate on the shape measuring surface of the steel sheet S after stretching, and the reciprocal of the stretching ratio is ρ, the steel sheet S Is extended in the longitudinal direction, the following equation (11) holds for the longitudinal coordinate x before stretching, the longitudinal coordinate X after stretching, and the reciprocal ρ of the stretching ratio.
dx / dX (x) = ρ (11)

  If the reciprocal number ρ of the expansion rate is set to “1”, expansion or contraction is not performed, and if the reciprocal number ρ of the expansion rate is set to a value smaller than “1”, the expansion state is set, and is set to a value larger than “1”. It becomes a reduced state. For this reason, as shown in FIG. 13, within the adjustment area Aa set on the front end side and the tail end side, the value is sequentially decreased to a value smaller than “1” as it goes from the inner side to the plate end, for example, 1/4 at the plate end. By setting the degree ρ = 0.25, the projection plane can be extended in the adjustment area Aa. In other areas excluding the adjustment area Aa, by setting ρ = 1, the expansion and reduction are not performed.

  Here, since the adjustment area Aa performs the measurement of the difference gap as shown in FIG. 5 at a position having a length L / 2 that is half the difference length L, the front end and the tail end in the longitudinal direction of the steel sheet S, and these This is a projection region surrounded by a line L1 parallel to the tip and tail ends taken from the tip and tail ends by a distance of ½ of the difference length, and both ends in the width direction. However, the setting of the adjustment area Aa does not need to be strictly set to L / 2, and can be set from a position having a length of L / 2 or more from the plate end to the plate end. Further, the adjustment area Aa can be set between the position from the plate end to the plate end where the length is smaller than L / 2 when the required measurement accuracy of the difference gap is low.

  The reciprocal ρ of the expansion rate in the adjustment area Aa is gradually decreased from ρ = 1 on the line L1 to the plate end side as shown by a convex quadratic curve L2 on the solid line in FIG. And ρ = 0.25 = 1/4 at the end of the plate. Therefore, when the reciprocal ρ of the expansion rate is gradually decreased from “1”, the projected coordinates of the respective point data in the longitudinal direction of the adjustment area Aa are expanded in the longitudinal direction from the line L1 toward the plate end, and the plate end Thus, the projected coordinates are expanded four times in the longitudinal direction.

  Note that the setting of the reciprocal ρ of the expansion rate in the adjustment area Aa is not limited to the case of setting an upward convex arc as shown by the solid line in FIG. 13, but decreases to a broken line as shown by the dotted line in FIG. 13 may be set so as to decrease linearly as shown by a one-dot chain line in FIG. 13, or a secondary projecting downward as shown by a broken line in FIG. You may make it set to a curve.

Moreover, it is preferable to set the reciprocal ρ of the elongation rate at the plate end to ρ ≧ 0.25. If ρ <0.25, the measurement points become too sparse, and the accuracy is worsened.
Therefore, from the above equation (11), the elongated longitudinal coordinate value X (x) can be calculated by the following equation (12).

And the longitudinal direction coordinate value x in the adjustment area | region Aa of the point cloud data of the steel plate S is converted into the longitudinal direction coordinate value X after expansion | extension by Formula (12). Here, the equation (12) is calculated by numerical integration so as to correspond to an arbitrary ρ.
The result of applying the low-pass filter of the second term on the right-hand side of Equation (2) described above to the point cloud data after the conversion of the longitudinal coordinate values of the point cloud data is finished, is the point cloud data before the coordinate conversion. Is subtracted from the result of applying the low-pass filter of the second term on the right-hand side of equation (2) to perform band-pass filter processing.

Therefore, by executing the filtering process shown in FIG. 14 with the shape measuring device 5, the difference gap can be calculated.
That is, first, in step S11, point cloud data of the position data of the steel sheet S is acquired from the laser distance meter, and then the process proceeds to step S12, where the first term on the right side of the equation (2) is obtained with respect to the acquired point cloud data. The low frequency filter on the high frequency side is applied to perform high frequency low pass filter processing, and the filter processing result is stored in a storage area such as a memory.

Subsequently, the process proceeds to step S13, and the calculation of the equation (12) is performed based on the reciprocal ρ of the expansion rate set in FIG. 13 described above for each longitudinal coordinate value x corresponding to the adjustment area Aa of the point cloud data. The process proceeds to step S14 after calculating the longitudinal coordinate value X (x) after expansion.
In step S14, coordinate conversion processing is performed to convert the longitudinal coordinate value x corresponding to the adjustment area Aa of the point cloud data into the elongated longitudinal coordinate value X (x), and then the process proceeds to step S15.

In step S15, the low-frequency low-pass filter processing of the second term on the right side of the above-described equation (2) is performed on the point cloud data after coordinate conversion, and the filter processing result is stored in a storage area such as a memory. Control goes to step S16.
In step S16, a band gap filter process for subtracting the low frequency band low pass filter process result from the high frequency band low pass filter process result is performed to calculate the difference gap.

As described above, in the present embodiment, on the plate end side of the tip and tail ends of the steel plate S, the adjustment region Aa takes a distance of ½ of the difference length from the plate end to the inside, toward the plate end from the inside. Accordingly, the reciprocal number ρ of the expansion rate is sequentially set to be smaller, thereby converting the longitudinal coordinate value x of the adjustment area Aa into the elongated longitudinal coordinate value X (x).
Therefore, the difference length L is relatively reduced, and the longitudinal coordinate value is expanded four times by setting the reciprocal ρ of the expansion rate to 0.25 at the plate end. For this reason, the difference length is relatively reduced to ¼ at the plate end.

Accordingly, as shown in FIG. 15, the difference gap when the filter processing of FIG. 14 is performed approaches “0” at both the front end and the tail end compared to FIG. It is possible to approach the difference gap equivalent to the difference gap at the time of measurement by the difference. For this reason, accurate difference clearance evaluation is possible on the entire surface of the steel sheet S in the longitudinal direction.
Therefore, it is possible to correct the shape of the steel sheet S with the press 1 based on the difference gap evaluation.

FIG. 16 shows specific results of a method for obtaining a difference gap from the difference between two smoothed spline curved surfaces. As described above, in the present embodiment, the method of obtaining the difference gap from the difference between the two smoothed spline curved surfaces is employed in the longitudinal direction of the steel plate, so here the longitudinal direction position and the height direction position are determined. Show. Smoothing error blocking curved surface shown in the figure, discounts for error blocking length (error cut-off wavelength) L _H discounts with smoothed smoothing spline curved surface, the reference curved surface is smoothed with discounts of discounts length L A spline curved surface, and the difference gap is obtained by subtracting the latter from the former.

  The difference gap thus obtained is shown in FIG. This differential gap is a representation of the differential gap of FIG. 8 from a viewpoint parallel to the surface of the steel plate, with positive values being convex and negative values being concave. As for the convex shape, two shims are laid under the steel plate sandwiching the convex portions as described above, and the convex portions between the shims are pressurized with a pressure ram. As for the concave shape, a single shim is laid under the concave portion, and pressure is applied with a pressure ram with shims interposed on both sides of the steel plate sandwiching the concave portion.

  FIG. 18 shows a correlation between the difference gap obtained by calculation and the difference gap measured by the operator using the difference. The difference between the two is within ± 0.3 mm, and a good correlation is observed. Therefore, instead of measuring the difference gap using the difference, the operator can properly evaluate the difference gap, that is, the shape of the steel sheet, using the shape measuring device and the control device, and using the result, the shape of the steel sheet Can be properly pressed.

  As described above, in the shape evaluation method and the steel plate shape correction method of the present embodiment, when the shape of the shape measurement surface of the shape evaluation object is evaluated using a computer having an arithmetic processing function, a difference in length set in advance is set. Is applied to the shape measurement surface of the shape evaluation object, and a measurement point on the shape measurement surface of the shape evaluation object using a bandpass filter having frequency response characteristics when measuring the gap between the difference and the shape measurement surface. A gap is obtained by applying a band pass filter to the point cloud data at the position.

  As this band pass filter, a smoothed spline curved surface obtained by smoothing the point cloud data with a smoothing degree corresponding to the difference length applied to the shape measurement surface, and shorter than the difference length applied to the shape measurement surface and From the difference from the second smoothed spline curved surface obtained by smoothing the point cloud data with a smoothing degree corresponding to the second difference length set in advance to block the error, the difference and the shape measurement surface Find the gap between. For this reason, the clearance gap between a difference metal and a shape measurement surface can be calculated | required correctly, and, thereby, the shape of a shape measurement surface can be evaluated appropriately.

In addition, it is possible to relatively reduce the difference length by extending the position coordinates in the measurement direction in the adjustment area Aa taken inward by a predetermined length from the end of the shape evaluation object and the plate end of the tail end. Become. For this reason, the difference gap at the plate end can be brought close to the difference gap at the time of measurement by an actual operator, and accurate shape evaluation can be performed on the entire surface of the steel sheet S in the measurement direction.
In addition, since the coordinate value in the measurement direction only needs to be extended in the adjustment area Aa that takes a distance L / 2 that is half the difference length L from the tip or tail end of the shape evaluation object, the length of the shape evaluation object Regardless of this, a predetermined decompression process can be applied.

Moreover, the shape evaluation object is a steel plate, and the position where the absolute value of the gap between the difference obtained by the shape evaluation method and the shape measurement surface is equal to or greater than a preset specified value is presented as the press correction position by the pressure ram. To do. Thereby, the steel plate which correct | amended the steel plate shape appropriately can be manufactured.
In addition, although the said embodiment demonstrated the case where shape evaluation was carried out about the longitudinal direction of the steel plate S, it is not limited to this, Shape evaluation can be performed with the same method also about the width direction.

  Moreover, although the said embodiment demonstrated the case where the extending | stretching process of a longitudinal direction coordinate was performed about both the front-end | tip and tail end of the steel plate S, it is not limited to this, The length of a shape evaluation object is long. In this case, it is possible to divide the shape measurement surface of the shape evaluation object into a plurality of shapes and perform the shape evaluation. In this case, the coordinate value expansion process of the adjustment region can be performed for the region including the tip or the tail. That's fine.

Moreover, in the said embodiment, although demonstrated the case where the shape of a steel plate was evaluated offline and corrected in the side of a rolling line, the steel plate shape correction method of this invention is applied online inside a rolling line. It is also possible.
Moreover, in the said embodiment, although it explained in full detail only about the steel plate rolled by the rolling line as a shape evaluation object, the shape evaluation method of this invention is not restricted to a steel plate, but the position of the measurement point on a shape measurement surface. Any shape evaluation object that can acquire point cloud data can be applied.

DESCRIPTION OF SYMBOLS 1 Press machine 2 Pressurization ram 3 Incoming bed 4 Outgoing bed 5 Shape measuring device 6 Control device 7 Position detection device 11 Laser light source 12 Turntable 13 Galvano mirror

Claims (6)

  When performing shape evaluation of the shape measurement surface of the shape evaluation object using a computer having an arithmetic processing function, a difference in length set in advance is applied to the shape measurement surface of the shape evaluation object, and the difference and the shape A phase compensation band-pass filter having frequency response characteristics when measuring the gap between the measurement surfaces is applied to point cloud data at the position of the measurement point on the shape measurement surface of the shape evaluation object, and the gap is formed. A shape evaluation method to be obtained, wherein projective coordinates are extended in an adjustment region from at least one measurement end of the shape evaluation object to a predetermined length inside.   2. The shape evaluation method according to claim 1, wherein the adjustment region is a region from an end face of the shape evaluation object to an inner side corresponding to a half of the difference.   The phase compensation bandpass filter is applied to a smoothed spline curved surface obtained by smoothing the point cloud data with a smoothing degree corresponding to a difference length applied to the shape measuring surface, and to the shape measuring surface. From the difference from the second smoothed spline curved surface obtained by smoothing the point cloud data with a smoothing degree that is shorter than the difference length and that corresponds to the second difference length set in advance to cut off the error. The shape evaluation method according to claim 1, wherein the gap is obtained.   The projection coordinate expansion rate in the adjustment region is set so as to increase from the inner end of the adjustment region toward the end surface of the shape evaluation object, and the reciprocal of the expansion rate is set to ¼ or more on the end surface. The shape evaluation method according to claim 1, wherein the shape evaluation method is performed.   When the shape evaluation object is a steel plate, a position where the absolute value of the gap obtained by the shape evaluation method according to any one of claims 1 to 4 is equal to or greater than a preset specified value is pressed. A method for correcting the shape of a steel sheet, characterized by being presented as a press correction position by a ram.   A steel sheet manufacturing method using the steel sheet shape correction method according to claim 5 in a steel sheet manufacturing process.

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