JPH05172560A - Measuring method of distortion shape of plate material - Google Patents

Abstract

PURPOSE:To enable highly accurate measurement and fast computation of a distortion shape by removing errors due to playing of a plate material and errors attributed to a long-term error of a displacement meter in the measurement of the distortion shape. CONSTITUTION:Displacements y1i and y2i are detected with displacement meters 1 and 2. An arithmetic device 12 determines a displacement difference dyi from the displacements y1i and y2i detected to obtain an integration waveform y3 of an integration computation (first) over the overall length in the longitudinal direction of a steel plate 3 from the displacement difference dyi. The first integration waveform y3 is converted to a second integration waveform y3' with a mean thereof zero. A sum of products function S is determined between a linear function which becomes zero at the center of a integration computation range and represents +1 and -1 at both ends thereof and a second integration waveform y3' converted. An inclination function G which is determined by the sum of products S is subtracted from the first integration waveform y3 to obtain a distortion shaped of the steel plate from a subtracted value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for accurately measuring the strained shape of a steel sheet and measuring the strained shape of the sheet material on a line through which the sheet material flows, which is suitable for high-speed arithmetic processing.

[0002]

2. Description of the Related Art There is an increasing demand for measuring the strain profile of a steel plate in a line for producing and processing a steel plate, for example, and several strain profile measuring devices (or flatness measuring devices) have been applied in the line. Are in a situation where

A typical representative example of a strain profile measuring device is as follows.
2. Description of the Related Art There is an apparatus for measuring displacement by providing a plurality of displacement measuring instruments such as laser displacement gauges in the width direction of a steel plate transport table.

That is, in this measuring apparatus, when the steel sheet is being conveyed by the conveying table, the vertical displacement of the steel sheet with respect to the reference level of the conveying table is measured at a plurality of positions in the steel sheet width direction in the conveying direction (steel sheet). The state of strain on the entire surface of the steel sheet is detected as shape data of strain, magnitude of strain, steepness value and the like.

Regarding such a strain shape measuring device, Japanese Patent Laid-Open No. 53-31159 (which measures the strain-shaped state by detecting the waveform of the rolled material at a plurality of positions which coincide with each other in the width direction) and Japanese Patent Laid-Open No. 59-230102 (Japanese Patent Laid-Open No. 59-230102). A water column type plate material distance detector is provided in the plate material width direction, and the detector is operated based on signals from the front and rear ends of the plate material) and JP-A-60-120202.
(Hydro sensor provided in the width direction (water column sensor)
There is a method for detecting the strained shape in the longitudinal direction of the plate material by comparing the relative relationship between the measured value and the set value simultaneously measured in (1).

Here, the factors that cause the steel material to be displaced in the vertical direction with respect to the reference level of the transport table are "strain of the steel plate" and "fluttering of the steel plate during transport".

An example of a possible method for separating and removing the displacement caused by the flapping of the steel sheet and accurately detecting the displacement generated only by the strain will be described.

FIG. 3 shows a state in which the steel sheet 3 transported on the transport table 5 has a wavy distortion at the wavelength Xa.

In order to measure the strain of the steel plate 3, as shown in FIG. 3, laser displacement is made in the longitudinal direction 4 of the steel plate 3 at a position separated by a distance l sufficiently smaller than the wavelength Xa of the strain of the steel plate 3. A total of 1 and 2 are provided. These two laser displacement gauges 1
2 and 2, the vertical displacements y1i and y2i (i: subscript indicating fluttering hi) of the steel plate 3 with respect to the reference level F of the transport table 5 are measured at the same time. Further, the difference dyi between the detected displacements at the two locations is measured in the conveying direction of the steel sheet 3 over the entire length of the steel sheet 3.

FIG. 4 shows a state where the steel plate 4 has flaps. The displacements y1i and y2i before and after the fluttering hi of the steel plate 3 is measured as follows. That is, in FIG. 4, the laser displacement meters 1 and 2 before the rattling i occurs
The displacements detected at are y11 and y21, and the displacements when flapping hi occurs are y12 and y22. Differences dy1 and dy2 of the displacement before and after the occurrence of flapping and the like are calculated by the following equations (1) and (2).

[0011]

[Equation 1]

[0012]

[Equation 2]

From these equations (1) and (2), the displacement difference dyi
Is calculated, the displacements y1i and y2i due to the flapping hi of the steel plate 3 are calculated.
The displacement difference dyi becomes the same before and after the change. Therefore, by using this displacement difference dyi, it is possible to obtain the displacement difference dyi over the entire length of the steel sheet 3 without a measurement error caused by the fluttering due to the conveyance of the steel sheet 3. Therefore, by calculating the displacement difference dyi into the necessary strain shape data, the strain data, the strain shape data, the magnitude of the strain, or the steepness value without the measurement error caused by the flapping of the steel plate 3 is measured. It is thought that it can be done.

When the displacement difference dyi is measured and the strain shape of the steel sheet 3 is obtained, when the strain is measured by the steepness value,
In the conventional arithmetic processing, the magnitude Z of the distortion is obtained by the following equation (3).

[0015]

[Equation 3]

By dividing the magnitude Z of strain obtained by the equation (3) by the wavelength Xa of strain, strain data (steepness value) from which the error due to the fluttering of the steel sheet 3 is removed can be measured.

Also, when the displacement difference dyi is measured over the entire length of the steel plate 3 and the strained shape is obtained over the entire length of the steel plate 3,
It is easy to find the distorted shape by removing the flapping of the steel plate 3.

[0018]

However, as described above, when the strained shape of the plate material (steel plate) is obtained from the difference in displacement (displacement difference dyi) measured by the displacement gauges provided at two locations, the cause of the error As a result, there is a long-term error (an error called an offset, an error called a drift, etc.) that occurs in each displacement meter, in addition to the fluttering of the plate that occurs when the plate is transported.

When the distortion shape of the entire length of the plate material is measured and the distortion shape calculation process is performed while the plate material is being conveyed on the conveyance table, in this calculation process, it is equivalent to the strain shape measured by placing the plate material on the surface plate offline. In order to obtain the strain shape calculation result that is the strain shape of the entire plate material, it is necessary to simply calculate the strain data by simply integrating the displacement difference dyi in the longitudinal direction of the plate as in the conventional case, Error is accumulated.

Therefore, conventionally, as described above, the strained shape when the strained shape of the entire length of the plate material is measured and the strained shape calculation process is performed during the transportation on the transport table, the strained shape is placed offline on the surface plate. There is a problem that the strained shape is significantly different from the measured strained shape.

For example, if there is no long-term error in each displacement gauge, strain shape data can be obtained as shown in FIG. 5 (A). When there is an error, as shown in FIG. 5B, an error in which long-term errors are integrated occurs.

The present invention has been made to solve the above-mentioned problems of the prior art, and eliminates errors caused by flapping of a plate material when measuring the strain shape by displacement gauges provided at two locations, and long-term operation of the displacement gauge. It is an object of the present invention to provide a method for measuring a strain profile of a plate material, which removes a measurement error due to a large error and enables high-speed calculation of strain profile measurement.

[0023]

SUMMARY OF THE INVENTION The present invention is a method for measuring the strained shape of a plate material in a line where the plate material is transported, in which two positions are provided in the plate material transport direction and at short intervals with respect to the strain wavelength of the plate material. The distance from the reference position to the plate is detected and
The difference between the respective distances detected at the location is integrated in the transport direction of the plate material to obtain a first integrated wavelength, and the first integrated waveform is converted into a second integrated waveform having an average value of zero, and integrated. A zero-value is obtained at the center of the calculation range, and a product-sum function of the linear function typified by the first and second predetermined values at both ends of the range and the converted second integral waveform is calculated. The problem is solved by subtracting the sum-of-products function from the first integrated waveform and obtaining the strain shape of the plate material from the subtracted value.

[0024]

The present invention will be described in detail with reference to FIGS. 3, 4 and 5.

As shown in FIGS. 3 and 4, the steel plate 3 being conveyed by the conveying table 5 causes a large amount of fluttering h due to collision with the conveying roll 6 or the like. In order to eliminate the distortion shape measurement error due to the fluttering h, laser displacement meters (corresponding to rangefinders) 1 and 2 are provided at two positions of a distance l (ell) sufficiently shorter than the distortion wavelength Xa of the steel plate 3. The vertical displacements y1i and y2i of the steel plate 3 with respect to the reference level F of the transport table 5 are measured from the laser displacement gauges 1 and 2, respectively. The measured displacements y1i and y2i are represented by the following equations (4) and (5) in consideration of the long-term errors e1 and e2 of the displacement gauges 1 and 2.

[0026]

[Equation 4]

[0027]

[Equation 5]

The difference dyi between the displacements y1i and y2i detected at these two points is integrated in the conveying direction 4 of the steel plate 3 (feeding direction; plate material longitudinal direction if it is a plate material), for example, for the entire plate material length L. The value y3 of this integration is represented by the following equation (6).

[0029]

[Equation 6]

The integrated value (first integrated waveform; an integrated waveform because it changes with a certain waveform) y3 includes a long-term error of the displacement meters 1 and 2.

Here, l is sufficiently smaller than the wavelength Xa of strain of the plate material 3, and the long-term errors e1 and e2 can be regarded as constant during the normal measurement time of the plate material 3. −e2
The value of is a steady value.

Therefore, the equation (6) can be transformed into the following equation (7).

[0033]

[Equation 7]

Then, if the first integrated waveform is converted so that the average value of y3 becomes zero, a second integrated waveform y3 'shown in the following equation (8) is obtained.

[0035]

[Equation 8]

Next, as shown in the following expression (9), the central value of the integral range (for example, the total length L of the plate material) becomes zero, and the first and second predetermined values, for example, +1 and -1, are represented at both ends as representatives. The sum-of-products function S of the linear function g (x) and the converted second integral waveform y3 'is obtained as in the following expression (10).

[0037]

[Equation 9]

[0038]

[Equation 10]

From the equation (10), the sum of products S becomes the term of the magnitude of the tilt component due to the long-term error of the displacement meter. If a slope function (11) is created from this S and removed from the original integrated waveform (first integrated waveform), the above-mentioned integrated waveform without long-term error can be obtained. Can be measured.

The present invention is based on the above idea. That is, as in the procedure shown in FIG. 1, the displacement difference dyi between the displacements y1i and y2i detected at two locations is integrated with respect to the plate material conveying direction 4 to, for example, the plate material total length L to obtain a first integrated waveform.

The average value of the first integral waveform y3 is converted into zero to obtain the second integral waveform, and the integral calculation range -L / 2 to L
/ 0 at the center of / 2, and a product-sum function of a linear function g (x) typified by first and second predetermined values at both ends and the converted second integral waveform y3 ' Find S.

This product-sum function becomes a term of the displacement type long-term error. Therefore, if the slope function G (x) obtained by the product-sum function S is subtracted from the first integral waveform y3, the plate material This represents a true integrated waveform that does not include the error due to the flutter but of course the error of the slope component due to the long-term error of the displacement gauges 1 and 2.

From this true integrated waveform, it is possible to obtain an accurate plate strain shape that does not include errors due to flapping but also long-term errors. Further, the strained shape of the plate material can be obtained by high-speed arithmetic processing even if the steel plate has a complicated strained shape.

The first and second predetermined values are +1 and-.
Although 1 is shown as an example, this value is not limited to +1 and -1, and other values are possible.

[0045]

Embodiments of the present invention will now be described in detail with reference to the drawings.

This embodiment is an apparatus for calculating the distortion shape of the steel plate 3 having the structure shown in FIG.

As shown in FIG. 1, this distortion shape calculating device is used in a conveying table 5 in a finishing line of a steel plate factory.
The strain shape of the steel sheet conveyed to the substrate is measured, and the strain shape inspection of the thick steel sheet product is performed based on the measured strain shape. This strain shape measuring device includes laser displacement meters 1 and 2, and a computing device 12. ing.

The displacement gauges 1 and 2 measure the vertical displacement of the steel plate 3 from the reference level F of the transport table 5. Further, the displacement gauges 1 and 2 are provided at two locations spaced apart from each other by, for example, 300 mm in the conveying direction of the steel plate 3. It should be noted that one or a plurality of displacement gauges 1 and 2 at each location are installed in the width direction of the steel plate 3. If a plurality of displacement gauges are installed in this way, it is possible to simultaneously measure the strain shape of the steel sheet 3 in the width direction.

A laser displacement meter can be used as the displacement meter, but this is one application example, and for example, a water column type distance meter can be used.

The arithmetic unit 12 includes the displacement gauges 1 and 2
The calculation of the distortion shape is performed based on the output signal of (1). For this device 12, for example, a microcomputer can be used.

Next, the operation of the embodiment will be described.

The detection signals of the displacement gauges 1 and 2 are used as the arithmetic unit 12
To enter. The arithmetic unit 12 performs the arithmetic operations of the above equations (4) to (11) according to the procedure shown in FIG.
And the integrated waveform (y3−G) having no long-term error of 2 is obtained. Then, the distortion shape of the steel plate 3 is measured by calculation based on this integral waveform (y3-G).

Therefore, the measured strained shape is one in which the measurement error due to the flapping h of the steel plate 3 caused by the collision with the conveying roller 6 or the like is removed, and the displacement gauges 1 and 2 have a long-term effect. The error (offset or drift error) is removed.

Therefore, in the strain profile measuring apparatus in which the strain profile of the steel sheet 3 is measured online on the transport table 5, the strain profile measurement result is in good agreement with the strain profile measured on the offline surface plate. It is possible to obtain such a result. Further, this strain shape measurement can be performed by high-speed arithmetic processing.

In the above-mentioned embodiment, a steel plate is exemplified as the plate material, but the plate material for which the strain shape can be measured by carrying out the present invention is not limited to such a steel plate, and other various plate materials can be used. The present invention can be used to measure strained shapes.

[0056]

As described above, according to the present invention, it is possible to eliminate the error of the strain shape measurement due to the fluttering caused by the plate material being conveyed on the line, and the long-term error of the displacement gauge itself. Can be completely removed. Therefore, it is possible to accurately measure the strain shape.

Further, the strained shape can be measured by a high-speed calculation, and the excellent effect that the strained shape of the plate material can be measured online in real time can be obtained.

[Brief description of drawings]

FIG. 1 is a flowchart for explaining the present invention.

FIG. 2 is a block diagram showing a configuration of a strain profile measuring apparatus according to an embodiment of the present invention.

FIG. 3 is a side sectional view showing distortion of a steel sheet on a general line.

FIG. 4 is a side sectional view showing an example of a state where flapping has occurred in the steel sheet.

FIG. 5 is a diagram showing an example of strain shape data in the case where there is a long-term error in the displacement meter and in the case where the displacement meter does not exist.

[Explanation of symbols]

 1, 2 ... Displacement meter, 3 ... Steel plate, 5 ... Conveying table, 6 ... Conveying roll, 12 ... Computing device.

Continuation of the front page (72) Inventor Akinobu Ogasawara 1-3-10 Shiragin, Ogurakita-ku, Kitakyushu, Fukuoka Inside Celtec Systems Co., Ltd.

Claims (1)

[Claims] 1. A method for measuring a strained shape of a plate material on a line where the plate material is conveyed, wherein a distance from a reference position to a plate material at two positions at a short distance with respect to a strain wavelength of the plate material is measured in a plate material conveyance direction. The second integrated waveform which is detected, and the first integrated waveform is obtained by integrating the difference between the respective distances detected at the two locations in the transport direction of the plate material to obtain the first integrated waveform. To a zero at the center of the range of the integration operation, and a product-sum function of the linear function typified by the first and second predetermined values at both ends of the range and the converted second integral waveform. And subtracting the product-sum function from the first integrated waveform, and determining the strain shape of the plate material from the reduced value.