Method for measuring physical quantities on the surface of a strip-shaped object, apparatus for measuring physical quantities on the surface of a strip-shaped object, method for controlling the shape of a strip-shaped object, method for manufacturing a steel plate, and equipment for manufacturing a steel plate.

Abstract

To provide a physical quantity measurement method and a physical quantity measurement device of a strip article surface capable of accurately measuring a physical quantity of the strip article surface even when a position and an inclination of the strip article fluctuate.SOLUTION: A physical quantity measurement method of a strip article surface measures a physical quantity of a surface of a strip article conveyed in a longitudinal direction. The physical quantity measurement method of the strip article surface includes: a measurement step of measuring a displacement amount and an inclination amount of the strip article with respect to a reference plane in the periphery of a measuring point; and a correction step of correcting measured values of the physical quantity at the measuring point by using a predetermined model and the displacement amount and the inclination amount measured in the measurement step. The model shows a relation between the displacement amount and the inclination amount of the strip article with respect to the reference plane at the measurement point and the measured values of the physical quantity at the measurement point.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for measuring a physical quantity on the surface of a strip-shaped object, a device for measuring a physical quantity on the surface of a strip-shaped object, a method for controlling the shape of a strip-shaped object, a method for manufacturing a steel sheet, and manufacturing equipment for a steel sheet.

Background Art

[0002] In the raw material industry, the measurement technology of physical quantities for product management is very important for maintaining stable product quality. Particularly in fields such as steel, non-ferrous metals, paper manufacturing, and resins, where coiled products are produced by winding strip-shaped long raw materials, it is necessary to ensure uniform product quality regardless of the width direction and longitudinal direction of the raw materials. In the manufacturing line of strip-shaped raw materials, the raw materials during processing are often wound around a plurality of rolls and conveyed while being further processed, and finally the processed raw materials are wound up to form coiled products. In such a manufacturing line, by installing sensors in the width direction of the raw material and measuring physical quantities in accordance with the conveyance of the raw material, the physical quantity distribution in the longitudinal direction (conveyance direction) of the raw material can be measured under relatively stable conditions.

[0003] However, when attempting to measure the physical quantity distribution in the longitudinal direction by increasing the number of measurement points in the width direction of the raw material, it is necessary to install a plurality of sensors in the width direction of the raw material or actively scan the sensors in the width direction of the raw material. For example, in the annealing line of thin steel sheets, which is one of the manufacturing lines in the steel industry, temperature management of the steel sheet for the purpose of product quality control is important, and information on the temperature distribution in the longitudinal direction of the steel sheet is obtained by constantly measuring the temperature at one point in the center of the width direction of the steel sheet using a radiation thermometer. On the other hand, when obtaining information on the temperature distribution in the width direction of the product, it is necessary to measure the temperature by actively scanning the measurement points in the width direction using a scanning radiation thermometer or the like.

[0004] Measuring the physical quantity distribution in the width direction of a product often requires measures to ensure uniform conditions for measurement, as disturbances are greater in this area compared to measuring the physical quantity distribution in the longitudinal direction of the product. For example, in eddy current testing equipment that detects defects on the surface of steel plates using eddy currents, the distance between the sensor head and the steel plate surface (lift-off) is extremely important. Therefore, if the shape or position of the steel plate changes due to warping or fluttering in the width direction during transport, these changes become disturbances that reduce the defect detection performance. Thus, when applying eddy current testing equipment to steel plates during transport, it is necessary to install the equipment in a position where the steel plate is always wrapped around the roll, thereby suppressing fluctuations in warping and fluttering and maintaining a uniform lift-off.

[0005] However, due to installation constraints, some measuring instruments cannot be installed in a position where the steel plate is always wrapped around a roll. For example, in the manufacturing line for zinc-plated steel sheets, one example is temperature measurement technology in the process where, after molten zinc is applied to the surface of the steel sheet in a molten zinc pod, the steel sheet is heated using an IH heater or the like during vertical transport to alloy the surface of the steel sheet. In this process, the steel sheet cannot be wrapped around the roll until the alloying of the molten zinc and the steel sheet has progressed, and the steel sheet is transported vertically for more than 50m, causing warping and fluttering, especially at the widthwise edges of the steel sheet. However, even in such a disturbance-filled process, it is necessary to measure the temperature distribution in the widthwise direction of the steel sheet from the perspective of uniformizing material properties (strength, toughness) and suppressing uneven alloying.

[0006] Given this background, conventional radiothermal thermometers with fixed emissivity suffer from large temperature measurement errors due to significant fluctuations in emissivity depending on the degree of alloying. Therefore, a technique has been proposed to correct emissivity using two types of reflection characteristics (see Patent Document 1). Furthermore, Patent Document 2 describes a technique in which a laser beam is scanned and irradiated onto a zinc-based hot-dip galvanized steel sheet, the tilt of the zinc-based hot-dip galvanized steel sheet is calculated from the position of maximum brightness of the reflected light, and the maximum brightness is corrected according to the calculated tilt using a predetermined calibration curve. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 7276515 (paragraphs 0026-0050, figures 1-4) [Patent Document 2] Patent No. 2733416 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] However, with the technology described in Patent Document 1, if the positional relationship between the radiation thermometer and the steel plate changes, it becomes impossible to accurately measure the reflectance. Measurement errors in reflectance lead to estimation errors in emissivity, which ultimately affect the temperature measurement error, so it is necessary to stabilize the transport position (pass line) of the steel plate and measure the reflectance under the same conditions. However, as mentioned above, it is difficult to install rolls on the line due to concerns such as the adhesion of molten zinc, and stabilizing the pass line by winding the steel plate onto the rolls is difficult. For this reason, with the technology described in Patent Document 1, it is difficult to accurately measure the temperature distribution in the width direction of the steel plate under conditions where there are shape fluctuations of the steel plate such as warping or fluttering. On the other hand, the technology described in Patent Document 2 has disadvantages such as being usable only for measurement methods that utilize the maximum brightness of reflected light, and causing a time lag because the laser beam is scanned, so it can only be applied in very limited situations.

[0009] The present invention has been made to solve the above problems, and its objective is to provide a method and apparatus for measuring physical quantities on the surface of a strip-shaped object that can accurately measure physical quantities on the surface of the strip-shaped object even when the position and inclination of the strip-shaped object fluctuate. Another objective of the present invention is to provide a method for controlling the shape of a strip-shaped object that can accurately control the shape of the strip-shaped object. Furthermore, another objective of the present invention is to provide a method and equipment for manufacturing steel plates that can produce steel plates with a high yield. [Means for solving the problem]

[0010] [1] The present invention relates to a method for measuring physical quantities on the surface of a strip-shaped object, which measures physical quantities on the surface of a strip-shaped object being transported in the longitudinal direction, and includes a measurement step of measuring the displacement and inclination of the strip-shaped object with respect to a reference plane around a measurement point, and a correction step of correcting the measured value of the physical quantity at the measurement point using a pre-constructed model and the displacement and inclination measured in the measurement step, wherein the model shows the relationship between the displacement and inclination of the strip-shaped object with respect to a reference plane at the measurement point and the measured value of the physical quantity at the measurement point.

[0011] [2] The method for measuring physical quantities on the surface of a strip-shaped object according to the present invention is the method for measuring physical quantities on the surface of a strip-shaped object described in [1] above, wherein the measurement step includes measuring the displacement and inclination of the strip-shaped object by measuring the shape profile of the surface of the strip-shaped object using a two-dimensional laser distance meter.

[0012] [3] The method for measuring physical quantities on the surface of a strip-shaped object according to the present invention is the method for measuring physical quantities on the surface of a strip-shaped object as described in [1] above, wherein the measurement step includes measuring the displacement and inclination of the strip-shaped object by using a plurality of spot laser distance meters to measure the displacement of the strip-shaped object at two or more points that lie on a straight line extending in the width direction of the strip-shaped object and sandwich the measurement point.

[0013] [4] A method for measuring physical quantities on the surface of a strip-shaped object according to the present invention is a method for measuring physical quantities on the surface of a strip-shaped object according to any one of [1] to [3] above, and includes a step of obtaining information regarding the distribution of the physical quantities in the width direction of the strip-shaped object by repeatedly performing the measurement step and the correction step while moving the measurement point along the width direction of the strip-shaped object.

[0014] [5] The present invention relates to a physical quantity measuring device for the surface of a strip-shaped object, which measures physical quantities on the surface of a strip-shaped object being transported in the longitudinal direction, and comprises: measuring means for measuring the displacement and inclination of the strip-shaped object with respect to a reference plane around a measurement point; and correction means for correcting the measured value of the physical quantity at the measurement point using a model and the displacement and inclination measured by the measuring means, wherein the model shows the relationship between the displacement and inclination of the strip-shaped object with respect to a reference plane at the measurement point and the measured value of the physical quantity at the measurement point.

[0015] [6] The method for controlling the shape of a strip-shaped object according to the present invention includes the step of controlling the shape of the strip-shaped object based on physical quantities on the surface of the strip-shaped object measured using the method for measuring physical quantities on the surface of the strip-shaped object described in any one of [1] to [4] above.

[0016] [7] The steel sheet manufacturing equipment according to the present invention includes the step of controlling the steel sheet manufacturing conditions based on the physical quantities of the surface of the steel sheet measured using the physical quantity measurement method of the surface of a strip-shaped object described in any one of [1] to [4] above.

[0017] [8] The steel plate manufacturing equipment according to the present invention comprises a physical quantity measuring device for the surface of a strip-shaped object as described in [5] above, and equipment for manufacturing a steel plate based on the physical quantities of the surface of the steel plate measured by the physical quantity measuring device for the surface of a strip-shaped object. [Effects of the Invention]

[0018] According to the method and apparatus for measuring physical quantities on the surface of a strip-shaped object according to the present invention, physical quantities on the surface of a strip-shaped object can be measured with high accuracy even when the position or inclination of the strip-shaped object fluctuates. Furthermore, according to the method for controlling the shape of a strip-shaped object according to the present invention, the shape of the strip-shaped object can be controlled with high accuracy. Moreover, according to the method and equipment for manufacturing steel plates according to the present invention, steel plates can be manufactured with a high yield. [Brief explanation of the drawing]

[0019] [Figure 1] Figure 1 is a flowchart showing the flow of physical quantity measurement processing according to an embodiment of the present invention. [Figure 2] Figure 2 is a diagram showing the configuration of the apparatus used in the measurement step according to the first embodiment of the present invention. [Figure 3] Figure 3 is a diagram showing the configuration of a modified example of the apparatus shown in Figure 2. [Figure 4] Figure 4 is a diagram showing the configuration of the apparatus used in the measurement step according to the second embodiment of the present invention. [Figure 5] Figure 5 is a diagram showing the configuration of the apparatus used in the physical quantity measurement processing of the example. [Figure 6] Figure 6 is a diagram showing the configuration of the apparatus used in the modeling method of the example. [Figure 7] Figure 7 is a diagram showing an example of the relationship between emissivity, specular reflectance (specular reflectance luminance value), and diffuse reflectance (diffuse reflectance luminance value). [Figure 8] Figure 8 is a diagram for explaining a method of selecting the type of light source considering specular reflection conditions.

Embodiments for Carrying Out the Invention

[0020] Hereinafter, referring to the drawings, a method for measuring a physical quantity on the surface of a strip-shaped object, a physical quantity measuring apparatus for the surface of a strip-shaped object, a method for controlling the shape of a strip-shaped object, a method for manufacturing a steel sheet, and a manufacturing facility for a steel sheet, which are embodiments of the present invention, will be described in detail.

[0021] 〔Modeling Method〕 In the physical quantity measurement process according to an embodiment of the present invention, before actually measuring the physical quantity, a model to be used is pre-constructed using the modeling method described below. In the modeling method of the present embodiment, an arithmetic unit (separate from the arithmetic unit 3 in FIG. 2) not shown constructs a model showing the relationship between the displacement amount and tilt amount from the reference plane of the surface of the strip-shaped object at the measurement point of the measuring device and the measured value of the measuring device. The modeling method can be executed at any time as long as a model can be obtained before being used in the correction step described later. Specifically, at the time of actual measurement, since the displacement amount Δx and tilt amount Δθ from the reference plane of the strip-shaped object surface are added to their respective reference values x0 and θ0, the displacement amount Δx and tilt amount Δθ from the reference plane of the strip-shaped object surface become disturbances to the measured value of the measuring device. Therefore, in the modeling method, the arithmetic unit constructs a model showing the relationship between the measured value T of the physical quantity of the measuring device at the measurement point and the displacement amount Δx and tilt amount Δθ with respect to the reference plane at the measurement point. In other words, in the modeling method, the arithmetic unit constructs a model showing the relationship between the function f(Δx, Δθ) represented by the displacement amount Δx and tilt amount Δθ and the measured value T. Note that the measured value T of the measuring device, the displacement amount Δx, and the tilt amount Δθ used when constructing the model are preferably obtained in a static environment such as a laboratory.

[0022] Specifically, when the displacement amount and tilt amount are the reference values x0 and θ0 respectively, and the measured value T of the measuring device becomes the true value T0, the arithmetic unit acquires the measured value T of the measuring device as measurement data while changing the displacement amount Δx and tilt amount Δθ. Then, the arithmetic unit constructs a model using the acquired measurement data. Here, it is desirable that the ranges of the displacement amount Δx and tilt amount Δθ when acquiring the measurement data comprehensively cover the range of the shape change conditions that the strip-shaped object can actually take. For example, assuming that the shape of the actual strip-shaped object changes within the ranges of xa < Δx < xb and θa < Δθ < θb, the range of the displacement amount Δx is equally divided into n - 1 parts, the range of the tilt amount Δθ is equally divided into m - 1 parts, and n × m shape change conditions of the strip-shaped object are created. Then, the arithmetic unit acquires measurement data under each shape change condition, and using the acquired measurement data, calculates an approximate expression showing the relationship between the measured value T and the displacement amount Δx and tilt amount Δθ of the strip-shaped object as shown in the following mathematical formula (1) as the model formula.

[0023]

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[0024] Furthermore, the function f(Δx,Δθ) in equation (1) should preferably be a function that fits the relationship between the displacement Δx and inclination Δθ of the strip-shaped object and the measured value T, and polynomial approximation formulas, Gaussian approximation formulas, exponential approximation formulas, sin approximation formulas (cos approximation formulas), etc., can be applied. Considering the simplest approximation using a quadratic surface, the function f(Δx,Δθ) can be expressed as shown in equation (2) below. In this case, the approximation formula is calculated by fitting the measured data to equation (2) and calculating the values ​​of the coefficients a to f in equation (2). It is desirable that the relationship between the measured values ​​of the measuring device during actual operation and the measured data used for model creation remain the same during actual operation. If the relationship between the measured values ​​of the measuring device during actual operation and the measured data used for model creation changes due to operating conditions, etc., it may become a new disturbance factor and reduce the measurement accuracy. Therefore, in this case, measures such as dividing the measurement data into ranges where the relationship between the measured values ​​from the measuring device during actual operation and the measurement data used for model creation can be considered identical, and constructing multiple approximation formulas using each divided measurement data, are necessary.

[0025]

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[0026] [Physical quantity measurement processing] Figure 1 is a flowchart showing the flow of a physical quantity measurement process according to one embodiment of the present invention. The physical quantity measurement process shown in Figure 1 is a process of measuring a physical quantity (e.g., temperature) on the surface of a strip-shaped object being transported in the longitudinal direction using a measuring device (e.g., a radiation thermometer). In this embodiment, it is assumed that the measured value of the measuring device is affected by the displacement and inclination of the strip-shaped object. In other words, it is assumed that the measured value of the measuring device changes according to the positional relationship between the measuring device and the strip-shaped object, and that an undisturbed measured value is obtained when the positional relationship does not change. That is, it is assumed that the true value of the measured value is obtained when the displacement and inclination of the strip-shaped object are at reference values.

[0027] In step S1, the computing unit measures physical quantities on the surface of the strip-shaped object using a measuring device, and also measures the displacement Δx and inclination Δθ of the strip-shaped object from the reference plane around the measurement point of the measuring device (measurement step). Details of this measurement step will be described later with reference to Figures 2 to 4. With this, the processing of step S1 is completed, and the physical quantity measurement process proceeds to step S2.

[0028] In step S2, the calculation unit corrects the measured value T of the measuring device using the model constructed in advance using the modeling method described above, and the displacement Δx and inclination Δθ of the strip-shaped object from the reference plane measured in step S1 (correction step). Specifically, the calculation unit calculates the value of the function f(Δx,Δθ) by substituting the displacement Δx and inclination Δθ of the strip-shaped object from the reference plane measured in step S1 into the pre-constructed formula (2). Then, the calculation unit calculates the true value T0 of the measured value T of the measuring device by substituting the calculated value of the function f(Δx,Δθ) and the measured value T of the measuring device into formula (1). Alternatively, the measurement step and correction step may be repeatedly executed while moving the measurement point of the physical quantity along the width direction of the strip-shaped object to obtain information on the distribution of the physical quantity in the width direction of the strip-shaped object. With this, the process of step S2 is completed, and the series of physical quantity measurement processes is finished.

[0029] [Measurement Steps] Next, the first and second embodiments of the above measurement step will be described with reference to Figures 2 to 4.

[0030] [First Embodiment] Figure 2 is a diagram illustrating the apparatus configuration for a measurement step according to the first embodiment of the present invention. In Figure 2, the strip-shaped object is assumed to be transported in the direction perpendicular to the plane of the paper. As shown in Figure 2, in the measurement step of this embodiment, a measuring device (in this example, a radiation thermometer, etc.) 1 is used to measure a physical quantity (temperature in this example) at a measurement point P on the surface of the strip-shaped object S. In this embodiment, a two-dimensional laser distance meter 2 is also placed in front of the strip-shaped object S in conjunction with the measuring device 1. Here, the two-dimensional laser distance meter is a device that divides a linear region along the width direction of the strip-shaped object S into equal parts and measures the distance between each division point (measurement position) and the two-dimensional laser distance meter. In Figure 2, the symbol R indicates the laser light emitted from the two-dimensional laser distance meter 2.

[0031] In this measurement step, the strip-shaped object S is being transported, and the measurement point P is not the part of the strip-shaped object S that is wrapped around a roll, so the displacement Δx and tilt Δθ of the strip-shaped object S are constantly changing. Therefore, if the measurement device 1 is introduced as is, the displacement Δx and tilt Δθ will become disturbances and change the measured value T. To address this, in this measurement step, first, the calculation device 3 synchronously acquires the measured value T and the measurement data from the two-dimensional laser distance meter 2. Then, the calculation unit 31 of the calculation device 3 uses the measurement data from the two-dimensional laser distance meter 2 to calculate the displacement Δx and tilt Δθ of the strip-shaped object S at the measurement point P. An example of the method for calculating the displacement Δx and tilt Δθ will be described below. Note that the calculation device 3 may be the same calculation device used in the modeling method.

[0032] Now, the measured values ​​at K measurement positions k (=1~K) of the two-dimensional laser distance meter 2 are x kIf we let k0 be the measurement position of the two-dimensional laser rangefinder 2 at which the measurement point P of the measuring device 1 and the widthwise position of the strip-shaped object S are the same, and let Δd be the distance between the measurement position k of the two-dimensional laser rangefinder 2, then the displacement Δx and tilt Δθ of the strip-shaped object S at measurement position k0 can be calculated using the following equations (3) and (4). In this example, the temperature of measurement point P is then corrected using the calculated displacement Δx and tilt Δθ, the temperature of measurement point P measured by the measuring device 1, and a pre-constructed model M. This model M was created using the modeling method described above.

[0033]

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[0034]

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[0035] The inclination amount Δθ may be calculated from the measured values ​​of the two-dimensional laser rangefinder 2 at two adjacent measurement positions, or it may be calculated by fitting a curve to the profile of the measured values ​​of the two-dimensional laser rangefinder 2 and differentiating it. Furthermore, the measured values ​​of the two-dimensional laser rangefinder 2 may be degraded by noise or defects if no processing is performed. For this reason, the displacement amount Δx and inclination amount Δθ may be calculated after removing noise from the measured values ​​of the two-dimensional laser rangefinder 2 using a frequency filter such as a low-pass filter, a median filter, or polynomial approximation.

[0036] Furthermore, it is desirable that the two-dimensional laser distance meter 2 be installed with high precision so that the displacement at each measurement position equals the reference value x0 when the surface of a strip-shaped object S, which has no fluctuations in displacement Δx and tilt Δθ, is used as the reference plane. However, due to issues such as installation conditions and precision, the two-dimensional laser distance meter 2 may be installed with tilt or positional misalignment relative to the reference plane. In this case, a calibration plate with high surface accuracy can be installed at the point through which the reference strip-shaped object S passes, and the distance to the reference plane can be measured using the two-dimensional laser distance meter 2. The measured values ​​at each measurement position at that time can be recorded as offset values, and the tilt and positional misalignment relative to the reference plane can be corrected by subtracting the offset value each time a measurement is taken.

[0037] Furthermore, if the measurement position of the two-dimensional laser distance meter 2 and the measurement point P are to be the same, the irradiation of laser light by the two-dimensional laser distance meter 2 may affect the measurement of the physical quantity at the measurement point P, potentially becoming a source of error. In addition, the measurement device 1 and the two-dimensional laser distance meter 2 may physically interfere with each other, making installation impossible. In such cases, interference between the measurement device 1 and the two-dimensional laser distance meter 2 can be avoided by setting the measurement position of the two-dimensional laser distance meter 2 and the measurement point P to different positions along the longitudinal direction of the strip-shaped object S.

[0038] Furthermore, as shown in Figure 3, instead of using the two-dimensional laser distance meter 2, the displacement Δx and tilt Δθ may be calculated by using spot laser distance meters 4a and 4b, which measure the displacement of the measurement positions adjacent to the measurement point P. In this case, it is preferable that the two spot laser distance meters 4a and 4b be installed at equidistant distances from the measurement point P, but they do not necessarily have to be at equidistant distances. Let a be the distance from the measurement point P to spot laser distance meter 4a, b be the distance from the measurement point P to spot laser distance meter 4b, and x be the output of each spot laser distance meter. A , x B Therefore, the displacement Δx and inclination Δθ can be calculated using the following formulas (5) and (6). In addition, although the example shown in Figure 3 measures the displacement at two points in the width direction of the strip-shaped object S, the displacement Δx and inclination Δθ can also be measured by measuring the displacement at three or more points in the width direction.

[0039]

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[0040]

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[0041] [Second Embodiment] Figure 4 is a diagram illustrating the apparatus configuration for a measurement step according to a second embodiment of the present invention. In Figure 4, the strip-shaped object S is assumed to be transported in the direction perpendicular to the plane of the paper. As shown in Figure 4, in the measurement step of this embodiment, a measuring device (in this example, a radiation thermometer, etc.) 1 is scanned in the width direction of the strip-shaped object S using a drive device 5 such as a linear slider, thereby measuring a physical quantity (temperature in this example) at multiple points along the width direction of the strip-shaped object S. At this time, it is desirable that the entire width of the strip-shaped object S always exists between the two ends of the measurement range of the two-dimensional laser distance meter 2. Under these conditions, one of the multiple measurement positions k of the two-dimensional laser distance meter 2 exists near the measurement point P, so the measured value can be corrected at each measurement point by calculating the displacement Δx and inclination Δθ of the nearby point using the measurement step of the first embodiment when scanning and measuring with the measuring device 1.

[0042] The position of measurement point P when the measuring device 1 is scanned may be derived from the displacement of the measuring device 1 by installing an encoder on the drive unit 5. Furthermore, for the widthwise region of the strip-shaped object S, the position of the widthwise end of the strip-shaped object S is calculated from the shape profile obtained by the two-dimensional laser distance meter 2, and the measurement point P is scanned so as to reciprocate between the widthwise ends of the strip-shaped object S. This allows measurement only of the region of the strip-shaped object S, and the position of each measurement point can be measured without being affected by the meandering of the strip-shaped object S. The shape profile described here is obtained by concatenating the distances measured at each measurement position and treating them as one-dimensional vector information.

[0043] Furthermore, a two-dimensional laser distance meter 2 may be mounted on the measuring device 1 and scanned together. In this case, the measurement position of the two-dimensional laser distance meter 2 is calculated from the encoder of the drive device 5, and by combining it with the measurement value of the two-dimensional laser distance meter 2, the widthwise end of the strip-shaped object S can be detected. At this time, if the laser light does not affect the intended measurement, the displacement amount Δx and tilt amount Δθ at the same position as the measurement point P on the strip-shaped object S may be measured. In addition, although a two-dimensional laser distance meter 2 was used in this embodiment, scanning can be performed similarly using two or more spot laser distance meters.

[0044] As is clear from the above explanation, in the physical quantity measurement process according to one embodiment of the present invention, the computing device measures the displacement Δx and inclination Δθ of the strip-shaped object S with respect to a reference plane around the measurement point P, corrects the measured value T of the physical quantity at the measurement point P using a pre-constructed model and the measured displacement Δx and inclination Δθ, and the model shows the relationship between the displacement Δx and inclination Δθ of the strip-shaped object S with respect to the reference plane at the measurement point P and the measured value T of the physical quantity at the measurement point P. As a result, even if the position or inclination of the strip-shaped object S fluctuates, the physical quantity on the surface of the strip-shaped object can be measured with high accuracy.

[0045] Furthermore, the physical quantity measurement process, which is one embodiment of the present invention, may be applied to a shape control method for a strip-shaped object, and the shape of the strip-shaped object may be controlled based on the physical quantities of the surface of the strip-shaped object measured by the physical quantity measurement process, which is one embodiment of the present invention. This makes it possible to control the shape of the strip-shaped object with high precision.

[0046] Furthermore, the physical quantity measurement process according to one embodiment of the present invention may be applied to a steel sheet manufacturing method, and the manufacturing conditions of the steel sheet may be controlled based on the physical quantities of the steel sheet surface measured by the physical quantity measurement process according to one embodiment of the present invention. This makes it possible to manufacture steel sheets with a high yield.

[0047] Furthermore, the present invention may be applied as a physical quantity measuring device constituting a steel sheet manufacturing facility, and steel sheets may be manufactured using the steel sheet manufacturing facility based on the physical quantities of the steel sheet surface measured by the physical quantity measuring device according to the present invention. In this case, the manufacturing facility for producing steel sheets may be known, unknown, or existing. This makes it possible to manufacture steel sheets with a high yield. [Examples]

[0048] The method for measuring the temperature of a zinc-based hot-dip galvanized steel sheet described in Patent Document 1 involves pre-modeling the relationship between two types of reflectivity (specular reflection and diffuse reflection) and radiance, and then estimating the emissivity by acquiring these two types of reflectivity from the steel sheet on the alloyed IH exit side using a specular reflection optical system and a diffuse reflection optical system, thereby accurately measuring the temperature of the steel sheet in response to emissivity fluctuations. In this method, it is important to accurately measure the specular reflection and diffuse reflection, but the measurement accuracy of these luminances largely depends on the displacement Δx and tilt Δθ of the measurement point. Therefore, even with the same surface condition, the reflectivity changes as the shape of the steel sheet changes due to warping or fluttering. Such changes result in errors in reflectivity, which in turn cause errors in the estimated emissivity, ultimately leading to a temperature measurement error. In this embodiment, the temperature of the zinc-based hot-dip galvanized steel sheet SA1 was measured by correcting the specular reflection and diffuse reflection by measuring the surface shape of the zinc-based hot-dip galvanized steel sheet SA1 using the apparatus shown in Figures 5(a) and (b). Note that the apparatus shown in Figures 5(a) and 5(b) is the same as the apparatus shown in Figure 3 described in the embodiment, but with the measuring device 1 replaced by a radiation thermometer 6.

[0049] Specifically, as shown in Figure 6, first, a steel plate sample SA2 was placed on a reference surface, and the light source 11 was set up in the same way as when actually measuring the reflectance. The displacement amount Δx of the steel plate sample SA2 could be adjusted by moving it vertically in parallel with respect to the reference position using a vertical scanning mechanism 13 such as a linear slider or jack, and the tilt amount Δθ could be adjusted by rotating it relative to the reference angle using a rotation mechanism 14 such as a goniometer stage or rotary stage. Next, the optical systems for specular reflection and diffuse reflection conditions were reproduced, and the reflectance was measured using a camera 12 when the displacement amount Δx and tilt amount Δθ of the steel plate sample SA2 were changed. Specifically, the maximum expected displacement amount Δx was set to 30 mm, and the maximum expected tilt amount Δθ was set to 4 degrees, and the setting conditions of the steel plate sample SA2 were changed to cover this range, and the reflectance was measured for each. Note that in the alloying process of zinc-based hot-dip galvanized steel sheets, the reflection state changes significantly due to changes in the surface properties of the steel sheet. More specifically, as shown in Figure 7(a), specular reflectance is important in the unalloyed state, but as shown in Figure 7(b), after a certain degree of alloying, the specular reflectance component almost disappears, and only diffuse reflectance becomes important. Therefore, specular reflectance was measured in the unalloyed sample, and diffuse reflectance was measured in the alloyed sample.

[0050] Table 1 shows the results of measuring the amount of reflected light in specular reflection within the range of -30 mm < Δx < 30 mm and -4 degrees < Δθ < 4 degrees.

[0051] [Table 1]

[0052] The reflected light quantities shown in Table 1 can be treated as correction coefficients for specular reflectance by normalizing them so that the light quantity at the reference surface is 1. By fitting the obtained correction coefficients to equation (2), the relationship between the displacement Δx and tilt Δθ and the specular reflectance f(Δx,Δθ) is modeled, and equation (7) shown below is obtained.

[0053]

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[0054] Next, a radiation thermometer described in Patent Document 1 was installed at the measurement point of the zinc-plated hot-dip steel sheet, and a two-dimensional laser distance meter was simultaneously installed at a position slightly away in the longitudinal direction so as not to interfere with the temperature measurement. From the output values ​​obtained at the same time as the measurement of the reflectance, the displacement Δx was calculated to be 15 mm and the tilt Δθ to be 1 degree. Then, the specular reflectance was corrected using the model calculated in the modeling step and the displacement Δx and tilt Δθ obtained in the measurement step. Substituting the displacement Δx and tilt Δθ of 15 mm and 1 degree, respectively, into the model equation, the value of the function f(Δx,Δθ) becomes 0.9929, and by dividing the obtained specular reflectance by this value, it can be considered to be under the same conditions as the value measured at the reference surface position. With this correction, the specular reflectance was calculated accurately without being affected by the displacement Δx and tilt Δθ of the zinc-plated hot-dip steel sheet SA1, and the temperature could be measured accurately even when the shape of the zinc-plated hot-dip steel sheet SA1 changed.

[0055] Regarding specular reflection luminance, within the range of the maximum values ​​of the assumed displacement Δx and tilt Δθ of the zinc-plated steel sheet, it is advisable to devise the type and installation position of the light source 11 so that the light-emitting surface of the light source 11 is always in the specular reflection direction under all conditions, thereby ensuring that a constant amount of reflected light is always obtained regardless of changes in the displacement Δx and tilt Δθ of the zinc-plated steel sheet. Specifically, as shown in Figure 8(a), when the light source is a point light source 11a, the specular reflection condition may not be met depending on the tilt of the zinc-plated steel sheet, and the amount of reflected light measured by the camera 12 decreases. In contrast, as shown in Figure 8(b), when the light source is a line light source 11b, the specular reflection condition is met somewhere on the light-emitting surface even if the zinc-plated steel sheet is tilted, so the amount of reflected light measured by the camera 12 does not decrease. In this way, by lengthening the light source in the direction of the assumed tilt of the zinc-plated steel sheet, and further uniformizing the amount of light emitted and directivity at each position on the light-emitting surface, it is possible to realize an optical system that stably maintains specular reflection conditions even when the position and tilt of the surface of the zinc-plated steel sheet change.

[0056] Although embodiments applying the invention made by the present inventors have been described above, the present invention is not limited by the descriptions and drawings that constitute part of the disclosure of the present invention in this embodiment. That is, all other embodiments, examples, and operational techniques made by those skilled in the art based on this embodiment are included in the scope of the present invention. [Explanation of Symbols]

[0057] 1. Measuring device 2. Two-dimensional laser distance meter 3 Computing device 4a, 4b Spot laser rangefinder 5. Drive unit 6 Radiation thermometer 11 Light source 11a Point light source 11b Line light source 12 cameras 13. Vertical scanning mechanism 14 Rotation mechanism 31 Calculation section M Model P measurement point S-shaped object SA1 zinc-plated hot-dip galvanized steel sheet SA2 Steel Plate Sample

Claims

1. A method for measuring physical quantities on the surface of a strip-shaped object that is transported in the longitudinal direction, wherein the physical quantity on the surface of the strip-shaped object is measured in the width direction, A measurement step of measuring the amount of displacement and inclination in the width direction of the strip-shaped object with respect to a reference plane around the measurement point, A correction step that corrects the measured values ​​of the physical quantities at the measurement points using a pre-constructed model and the widthwise displacement and inclination measured in the measurement step, Includes, The model shows the relationship between the displacement and inclination of the strip-shaped object in the width direction relative to the reference plane at the measurement point and the measured values ​​of the physical quantities at the measurement point. The measurement step includes measuring the widthwise displacement and inclination of the strip-shaped object by measuring the widthwise shape profile of the surface of the strip-shaped object using a two-dimensional laser distance meter. A method for measuring physical quantities on the surface of a strip-shaped object.

2. A method for measuring a physical quantity on the surface of a strip-shaped object according to claim 1, comprising the step of obtaining information regarding the distribution of the physical quantity in the width direction of the strip-shaped object by repeatedly performing the measurement step and the correction step while moving the measurement point along the width direction of the strip-shaped object.

3. A physical quantity measuring device for the surface of a strip-shaped object that is transported in the longitudinal direction, which measures the physical quantity in the width direction of the surface of the strip-shaped object, A measuring means for measuring the amount of displacement and inclination in the width direction of the strip-shaped object with respect to a reference plane around the measurement point, A correction means comprising a model, which corrects the measured value of the physical quantity at the measurement point using the displacement and inclination in the width direction measured by the model and the measuring means, Equipped with, The model shows the relationship between the displacement and inclination of the strip-shaped object in the width direction relative to the reference plane at the measurement point and the measured values ​​of the physical quantities at the measurement point. A device for measuring physical quantities on the surface of a strip-shaped object.

4. A method for controlling the shape of a strip-shaped object, comprising the step of controlling the shape of the strip-shaped object based on a physical quantity in the width direction of the surface of the strip-shaped object measured using the method for measuring physical quantities of the surface of the strip-shaped object described in claim 1 or 2.

5. A method for manufacturing a steel sheet, comprising the step of controlling the manufacturing conditions of a steel sheet based on a physical quantity in the width direction of the surface of the steel sheet measured using the method for measuring physical quantities of the surface of a strip-shaped object described in claim 1 or 2.

6. A physical quantity measuring device for the surface of a strip-shaped object according to claim 3, Equipment for manufacturing steel plates based on physical quantities in the width direction of the surface of the steel plate measured by the physical quantity measuring device for the surface of the strip-shaped object, Steel plate manufacturing equipment equipped with the necessary components.

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