Physical quantity measurement method of strip article surface, physical quantity measurement device of strip article surface, shape control method of strip article, production method of steel sheet, and production facility of steel sheet

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 of a surface of a strip-like object, an apparatus for measuring a physical quantity of a surface of a strip-like object, a method for controlling the shape of a strip-like object, a method for manufacturing a steel plate, and a steel plate manufacturing facility. [Background technology]

[0002] In the materials industry, technology for measuring physical quantities for product management is extremely important in maintaining stable product quality. In particular, in the fields of steel, nonferrous metals, paper, resin, and other industries where coiled products are produced by winding strip-shaped long materials, it is necessary to ensure uniform product quality regardless of the width and length of the material. In manufacturing lines for strip-shaped materials, the material in the middle of processing is often wound around multiple rolls and further processed while being transported, and finally the processed material is wound up to produce a coiled product. In such manufacturing lines, the physical quantity distribution in the lengthwise direction (transport direction) of the material can be measured under relatively stable conditions by installing sensors in the width direction of the material and measuring the physical quantities as the material is transported.

[0003] However, when trying to measure the longitudinal physical quantity distribution by increasing the number of measurement points in the width direction of the material, it is necessary to install multiple sensors in the width direction of the material, or to actively scan the sensor in the width direction of the material. For example, in a thin steel plate annealing line, which is one of the steel manufacturing lines, temperature control of the steel plate is important for the purpose of controlling the product quality, and information on the longitudinal temperature distribution of the steel plate is obtained by constantly measuring the temperature at one point in the center of the width direction of the steel plate 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] In measuring the distribution of physical quantities in the width direction of such products, disturbances are greater than in measuring the distribution of physical quantities in the length direction of the product, so measures are often required to measure the distribution of physical quantities under uniform conditions. For example, in an eddy current inspection device that uses eddy currents to detect defects on the surface of a steel plate, the distance (lift-off) between the sensor head and the steel plate surface is very important. Therefore, if the shape and position of the steel plate fluctuates due to warping or fluttering in the width direction of the steel plate while it is being transported, the fluctuations become a disturbance factor and the defect detection performance decreases. Therefore, when applying an eddy current inspection device to a steel plate being transported, measures are required to suppress the fluctuations in warping and fluttering and keep the lift-off uniform by installing the device at a position where the steel plate is always wrapped around the roll.

[0005] However, due to restrictions on the installation position, some measuring instruments cannot be installed at a position where the steel sheet is always wound around the roll. For example, in a manufacturing line for zinc-based hot-dip galvanized steel sheets, after molten zinc is applied to the surface of the steel sheet in a molten zinc pot, the steel sheet is heated using an induction heater or the like during the process of conveying the steel sheet vertically to alloy the surface of the steel sheet. In this process, the steel sheet cannot be wound around the roll until the alloying of the molten zinc and the steel sheet progresses, and the steel sheet is conveyed vertically for more than 50 m, so warping and fluttering occur especially at the ends in the width direction of the steel sheet. However, even in such a process with many disturbances, it is necessary to measure the temperature distribution in the width direction of the steel sheet from the viewpoint of uniforming the material properties (strength, toughness) and suppressing uneven alloying.

[0006] In light of this background, a technology has been proposed that uses two types of reflection characteristics to correct the emissivity (see Patent Document 1), since in conventional radiation temperature measurement with a fixed emissivity, the emissivity fluctuates greatly depending on the progress of alloying, resulting in large temperature measurement errors. Patent Document 2 also describes a technology in which a zinc-based hot-dip galvanized steel sheet is irradiated with a laser beam by scanning it, the inclination 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 using a predetermined calibration curve according to the calculated inclination. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 7276515 (paragraphs 0026-0050, figures 1-4) [Patent Document 2] Patent No. 2733416 Summary of the Invention [Problem to be solved by the invention]

[0008] However, in the technology described in Patent Document 1, when the positional relationship between the radiation thermometer and the steel sheet changes, the reflected luminance cannot be measured with high accuracy. Since the measurement error of the reflected luminance leads to an estimation error of the emissivity, which ultimately affects the temperature measurement error, it is necessary to stabilize the conveying position (pass line) of the steel sheet and measure the reflected luminance under the same conditions. However, as described above, it is difficult to install rolls on the line due to concerns such as adhesion of molten zinc, and it is difficult to stabilize the pass line by winding the steel sheet around the roll. For this reason, in the technology described in Patent Document 1, it is difficult to accurately measure the temperature distribution in the width direction of the steel sheet under conditions where the shape of the steel sheet varies, such as warping or flapping. On the other hand, the technology described in Patent Document 2 has disadvantages such as being usable only for a measurement method that utilizes the maximum luminance of reflected light, and a time lag occurs because laser light is scanned, and can only be applied to very limited situations.

[0009] The present invention has been made to solve the above problems, and an object of the present invention is to provide a method and device for measuring physical quantities of a surface of a strip-like object, which are capable of measuring the physical quantities of the surface of the strip-like object with high accuracy even when the position or inclination of the strip-like object varies. Another object of the present invention is to provide a method for controlling the shape of a strip-like object with high accuracy. Still another object of the present invention is to provide a method and equipment for manufacturing steel plate, which are capable of manufacturing steel plate with high yield. [Means for solving the problem]

[0010] [1] The method for measuring a physical quantity of a surface of a strip-like object according to the present invention is a method for measuring a physical quantity of the surface of a strip-like object transported in a longitudinal direction, and includes a measurement step of measuring a displacement and inclination amount of the strip-like object relative to a reference plane in the vicinity of a measurement point, and a correction step of correcting a measurement value of the physical quantity at the measurement point using a pre-constructed model and the displacement and inclination amount measured in the measurement step, wherein the model indicates the relationship between the displacement and inclination amount of the strip-like object relative to the reference plane at the measurement point and the measurement value of the physical quantity at the measurement point.

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

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

[0013] [4] The method for measuring a physical quantity of a surface of a strip-like object according to the present invention is a method for measuring a physical quantity of a surface of a strip-like object as described in any one of [1] to [3] above, and includes a step of acquiring information regarding the distribution of the physical quantity in the width direction of the strip-like object by repeatedly executing the measurement step and the correction step while moving the measurement point along the width direction of the strip-like object.

[0014] [5] The physical quantity measuring device for the surface of a strip-like object of the present invention is a physical quantity measuring device for the surface of a strip-like object that measures the physical quantities of the surface of the strip-like object transported in a longitudinal direction, and is equipped with a measuring means for measuring the displacement and inclination of the strip-like object relative to a reference plane in the vicinity of a measurement point, and a model, and a correction means for correcting the measured value of the physical quantity at the measurement point using the model and the displacement and inclination measured by the measuring means, wherein the model indicates the relationship between the displacement and inclination of the strip-like object relative to the reference plane at the measurement point and the measured value of the physical quantity at the measurement point.

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

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

[0017] [8] The steel plate manufacturing equipment of the present invention comprises the physical quantity measuring device for the surface of a strip-like object described in [5] above, and equipment for manufacturing 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 the strip-like object. Effect of the Invention

[0018] The physical quantity measuring method and physical quantity measuring device of the present invention can measure the physical quantities of the surface of a strip-like object with high accuracy even when the position or inclination of the strip-like object varies. The shape control method of a strip-like object of the present invention can control the shape of a strip-like object with high accuracy. Furthermore, the steel plate manufacturing method and manufacturing equipment of the present invention can manufacture steel plates with high yield. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a flowchart showing the flow of a physical quantity measurement process according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing the configuration of an apparatus used in the measuring step according to the first embodiment of the present invention. [Diagram 3] FIG. 3 is a diagram showing the configuration of a modified example of the device shown in FIG. [Figure 4] FIG. 4 is a diagram showing the configuration of an apparatus used in the measuring step according to the second embodiment of the present invention. [Diagram 5] FIG. 5 is a diagram showing the configuration of an apparatus used in the physical quantity measurement process of the embodiment. [Figure 6] FIG. 6 is a diagram showing the configuration of an apparatus used in the modeling method of the embodiment. [Figure 7] FIG. 7 is a diagram showing an example of the relationship between emissivity and regular reflectance (specular reflection luminance value) and diffuse reflectance (diffuse reflection luminance value). [Figure 8] FIG. 8 is a diagram for explaining a method of selecting the type of light source taking into consideration the specular reflection condition. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, with reference to the drawings, a method for measuring a physical quantity of a surface of a strip-like object, an apparatus for measuring a physical quantity of a surface of a strip-like object, a method for controlling the shape of a strip-like object, a method for manufacturing a steel plate, and a steel plate manufacturing equipment, 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 modeling method described below is used to pre-construct the model to be used. In the modeling method of this embodiment, an arithmetic unit (different 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 belt-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, during actual measurement, since the displacement amount Δx and tilt amount Δθ from the reference plane of the surface of the belt-shaped object are added to the respective reference values x0 and θ0, the displacement amount Δx and tilt amount Δθ from the reference plane of the surface of the belt-shaped object 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 belt-shaped object can actually take. For example, assuming that the shape of the actual belt-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 different shape change conditions of the belt-shaped object are created. Then, the arithmetic unit acquires measurement data under each shape change condition and calculates, as the model formula, an approximate formula showing the relationship between the measured value T and the displacement amount Δx and tilt amount Δθ of the belt-shaped object as shown in the following mathematical formula (1) using the acquired measurement data.

[0023]

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[0024] The function f(Δx, Δθ) in the formula (1) is preferably a function that fits the relationship between the displacement amount Δx and the tilt amount Δθ of the belt-like object and the measurement value T, and a polynomial approximation formula, a Gaussian approximation formula, an exponential function approximation formula, a sin approximation formula (cos approximation formula), etc. can be applied. Considering the simplest approximation using a quadric surface, the function f(Δx, Δθ) is expressed as the following formula (2). In this case, the approximation formula is calculated by fitting the measurement data to the formula (2) to calculate the values ​​of the coefficients a to f in the formula (2). It is preferable that the relationship between the measurement value of the measuring device during actual operation and the measurement data used to create the model is always the same during actual operation. If the relationship between the measurement value of the measuring device during actual operation and the measurement data used to create the model changes depending on the 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 in which the relationship between the measurement values ​​of the measuring device during actual operation and the measurement data used to create the model can be considered to be the same, and constructing multiple approximation equations using each divided measurement data are necessary.

[0025]

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[0026] [Physical quantity measurement processing] FIG. 1 is a flowchart showing the flow of a physical quantity measurement process according to an embodiment of the present invention. The physical quantity measurement process shown in FIG. 1 is a process for measuring a physical quantity (e.g., temperature) of the surface of a strip-like object transported in the longitudinal direction using a measurement device (e.g., a radiation thermometer). In this embodiment, it is assumed that the measurement value of the measurement device is affected by the displacement and tilt of the strip-like object. In other words, it is assumed that the measurement value of the measurement device changes depending on the positional relationship between the measurement device and the strip-like object, and that a measurement value without disturbance is obtained when the positional relationship does not change. In other words, it is assumed that a true measurement value is obtained when the displacement and tilt of the strip-like object are reference values.

[0027] In the process of step S1, the calculation device uses a measurement device to measure the physical quantities of the surface of the belt-like object, and also measures the amount of displacement Δx and the amount of inclination Δθ of the belt-like object from a reference surface around a measurement point of the measurement device (measurement step). Details of this measurement step will be described later with reference to Figures 2 to 4. This completes the process of step S1, and the physical quantity measurement process proceeds to the process of step S2.

[0028] In the process of step S2, the arithmetic device corrects the measurement value T of the measuring device using a model previously constructed using the above-mentioned modeling method and the amount of displacement Δx and amount of inclination Δθ of the band-like object from the reference plane measured in the process of step S1 (correction step). Specifically, the arithmetic device calculates the value of function f(Δx, Δθ) by substituting the amount of displacement Δx and amount of inclination Δθ of the band-like object from the reference plane measured in the process of step S1 into formula (2) previously constructed. Then, the arithmetic device calculates the true value T0 of the measurement value T of the measuring device by substituting the calculated value of function f(Δx, Δθ) and the measurement value T of the measuring device into formula (1). Note that information on the distribution of the physical quantity in the width direction of the band-like object may be obtained by repeatedly executing the measurement step and the correction step while moving the measurement point of the physical quantity along the width direction of the band-like object. This completes the process of step S2, and a series of physical quantity measurement processes ends.

[0029] [Measurement step] Next, a first and a second embodiment of the measuring step will be described with reference to FIGS.

[0030] [First embodiment] FIG. 2 is a diagram of an apparatus configuration for explaining a measurement step according to a first embodiment of the present invention. In FIG. 2, it is assumed that the belt-like object is transported in a direction perpendicular to the paper surface. As shown in FIG. 2, in the measurement step according to this embodiment, a measurement device (such as a radiation thermometer in this example) 1 is used to measure a physical quantity (temperature in this example) of a measurement point P on the surface of the belt-like object S. In addition, in this embodiment, a two-dimensional laser range finder 2 is installed in front of the belt-like object S in addition to the measurement device 1. Here, the two-dimensional laser range finder is a device that equally divides a linear area along the width direction of the belt-like object S and measures the distance between each division point (measurement position) and the two-dimensional laser range finder. In FIG. 2, the symbol R indicates a laser beam irradiated from the two-dimensional laser range finder 2.

[0031] In this measurement step, the belt-like object S is being transported, and the measurement point P is not a roll-wrapped portion of the belt-like object S, so the displacement amount Δx and tilt amount Δθ of the belt-like object S are constantly changing. For this reason, if the measurement device 1 is introduced as is, the displacement amount Δx and tilt amount Δθ will become disturbances and the measurement value T will change. Therefore, in this measurement step, the calculation device 3 first synchronously captures the measurement value T and the measurement data of the two-dimensional laser range finder 2. Then, the calculation unit 31 of the calculation device 3 calculates the displacement amount Δx and tilt amount Δθ of the belt-like object S at the measurement point P using the measurement data of the two-dimensional laser range finder 2. An example of a method for calculating the displacement amount Δx and tilt amount Δθ will be described below. The calculation device 3 may be the same as the calculation device used in the modeling method.

[0032] Now, let x be the measurement values ​​at K measurement positions k (=1 to K) of the two-dimensional laser range finder 2. kIf the measurement position of the two-dimensional laser range finder 2 where the measurement point P of the measurement device 1 and the width direction position of the band-like object S are the same is k0 and the interval between the measurement positions k of the two-dimensional laser range finder 2 is Δd, the displacement amount Δx and tilt amount Δθ of the band-like object S at the measurement position k0 can be calculated by the following formulas (3) and (4). In this example, the temperature of the measurement point P is then corrected using the calculated displacement amount Δx and tilt amount Δθ, the temperature of the measurement point P measured by the measurement device 1, and a model M constructed in advance. Note that this model M was created using the modeling method described above.

[0033]

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[0034]

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[0035] The tilt amount Δθ may be calculated from the measurement values ​​of the two-dimensional laser rangefinder 2 at two adjacent measurement positions, or may be calculated by fitting a curve to the profile of the measurement values ​​of the two-dimensional laser rangefinder 2 and differentiating it. Furthermore, the measurement values ​​of the two-dimensional laser rangefinder 2 may be degraded by noise, defects, etc., if they are not processed. For this reason, the displacement amount Δx and the tilt amount Δθ may be calculated after removing noise from the measurement values ​​of the two-dimensional laser rangefinder 2 using a frequency filter such as a low-pass filter, a median filter, polynomial approximation, etc.

[0036] Moreover, it is desirable to install the two-dimensional laser range finder 2 with high precision so that the displacement amount at each measurement position becomes the reference value x0 when the surface of the strip-shaped object S without fluctuations in the displacement amount Δx and the tilt amount Δθ is used as the reference plane for measurement. However, due to issues such as installation conditions and precision, the two-dimensional laser range finder 2 may be installed with tilt or positional deviation from the reference plane. In this case, a calibration plate with high surface precision may be installed at the position where the strip-shaped object S passes as the reference plane to measure the distance to the reference plane using the two-dimensional laser range finder 2, and the measured values ​​at each measurement position at that time may be recorded as offset values, and the tilt and positional deviation from the reference plane may be corrected by subtracting the offset value each time a measurement is performed.

[0037] Furthermore, if the measurement position of the two-dimensional laser rangefinder 2 and the measurement point P are to be the same, the irradiation of the laser light by the measurement of the two-dimensional laser rangefinder 2 itself may affect the measurement of the physical quantity at the measurement point P, resulting in a possibility of an error. There is also a possibility that the measurement device 1 and the two-dimensional laser rangefinder 2 may physically interfere with each other and may not be able to be installed. In such a case, the measurement position of the two-dimensional laser rangefinder 2 and the measurement point P may be set to different positions in the longitudinal direction of the belt-like object S, thereby avoiding interference between the measurement device 1 and the two-dimensional laser rangefinder 2.

[0038] Furthermore, as shown in Fig. 3, the displacement amount Δx and the tilt amount Δθ may be calculated by using spot laser rangefinders 4a and 4b that measure the displacement amounts of measurement positions on both sides of the measurement point P, instead of using the two-dimensional laser rangefinder 2. In this case, the two spot laser rangefinders 4a and 4b are preferably installed at equal distances from the measurement point P, but they do not necessarily have to be at equal distances. Let a be the distance from the measurement point P to the spot laser rangefinder 4a, b be the distance from the measurement point P to the spot laser rangefinder 4b, and x be the output of each spot laser rangefinder. A , x B Then, the displacement amount Δx and the tilt amount Δθ can be calculated by the following formulas (5) and (6). In the example shown in Fig. 3, the displacement amounts at two points in the width direction of the strip-shaped object S are measured, but the displacement amount Δx and the tilt amount Δθ may be measured by measuring the displacement amounts at three or more points in the width direction.

[0039]

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[0040]

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[0041] [Second embodiment] FIG. 4 is a diagram showing the configuration of an apparatus for explaining the measurement step according to the second embodiment of the present invention. In FIG. 4, the strip-shaped object S is assumed to be transported in a direction perpendicular to the paper surface. As shown in FIG. 4, in the measurement step according to this embodiment, a driving device 5 such as a linear slider is used to scan a measuring device (such as a radiation thermometer in this example) 1 in the width direction of the strip-shaped object S, 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 is always present between both ends of the measurement range of the two-dimensional laser range finder 2. Under such conditions, any one of the multiple measurement positions k of the two-dimensional laser range finder 2 is present in the vicinity of the measurement point P, so that the measurement value at each measurement point can be corrected by calculating the displacement amount Δx and the tilt amount Δθ of the neighboring point by the measurement step according to the first embodiment when the measuring device 1 is scanned and measured.

[0042] The position of measurement point P when measuring device 1 is scanned may be derived from the displacement of measuring device 1 by installing an encoder on driving device 5. For the widthwise region of belt-like object S, the positions of the widthwise ends of belt-like object S are calculated from the shape profile obtained by two-dimensional laser distance meter 2, and measurement point P is scanned so as to travel back and forth between both widthwise ends of belt-like object S. This makes it possible to measure only the region of belt-like object S, and to measure the position of each measurement point without being affected by the meandering of belt-like object S. The shape profile described here is obtained by connecting the distances measured at each measurement position and treating it as one-dimensional vector information.

[0043] Furthermore, a two-dimensional laser range finder 2 may be mounted on the measurement device 1 and scanned together. In this case, the measurement position of the two-dimensional laser range finder 2 is calculated from the encoder of the drive device 5, and the width direction end of the strip-like object S can be detected by combining this with the measurement value of the two-dimensional laser range finder 2. In this case, if the laser light does not affect the intended measurement, the displacement amount Δx and tilt amount Δθ may be measured at the same position as the measurement point P on the strip-like object S. Also, although the two-dimensional laser range finder 2 is used in this embodiment, scanning can also be performed in the same manner using spot laser range finders of two or more points.

[0044] As is clear from the above description, in the physical quantity measurement process according to one embodiment of the present invention, the calculation device measures the displacement amount Δx and tilt amount Δθ of the band-like object S relative to a reference plane around the measurement point P, and corrects the measurement value T of the physical quantity at the measurement point P using a pre-constructed model and the measured displacement amount Δx and tilt amount Δθ, and the model indicates the relationship between the displacement amount Δx and tilt amount Δθ of the band-like object S relative to the reference plane at the physical quantity measurement point P, and the measurement value T of the physical quantity at the measurement point P. This makes it possible to accurately measure the physical quantity of the surface of the band-like object even if the position or tilt of the band-like object S fluctuates.

[0045] Furthermore, the physical quantity measurement process according to an embodiment of the present invention may be applied to a shape control method for a band-like object for controlling the shape of the band-like object, and the shape of the band-like object may be controlled based on the physical quantities of the surface of the band-like object measured by the physical quantity measurement process according to an embodiment of the present invention, thereby enabling the shape of the band-like object to be controlled with high accuracy.

[0046] Furthermore, the physical quantity measurement process according to an embodiment of the present invention may be applied to a steel plate manufacturing method for manufacturing a steel plate, and manufacturing conditions for the steel plate may be controlled based on the physical quantities of the surface of the steel plate measured by the physical quantity measurement process according to an embodiment of the present invention. This allows the steel plate to be manufactured with a high yield.

[0047] Furthermore, the present invention may be applied as a physical quantity measuring device constituting a steel plate manufacturing facility, and a steel plate may be manufactured using the steel plate manufacturing facility based on the physical quantities of the surface of the steel plate measured by the physical quantity measuring device according to the present invention. In this case, the manufacturing facility for manufacturing the steel plate may be publicly known, unknown, or existing. This allows the steel plate to be manufactured with a high yield. EXAMPLES

[0048] The temperature measurement method of a zinc-based hot-dip galvanized steel sheet described in Patent Document 1 is a method in which the relationship between the two types of reflection brightness, specular reflection and diffuse reflection, and the radiance is modeled in advance, and two types of reflection brightness are obtained from the steel sheet at the outlet side of the alloying IH using a specular reflection optical system and a diffuse reflection optical system to estimate the emissivity, thereby measuring the temperature of the steel sheet with high accuracy against the emissivity fluctuation. In this method, it is important to measure the specular reflection brightness and the diffuse reflection brightness with high accuracy, but the measurement accuracy of these brightnesses is largely dependent on the displacement amount Δx and the inclination amount Δθ of the measurement point. Therefore, the reflection brightness changes even in the same surface condition due to the shape of the steel sheet changing due to the warping or flapping of the steel sheet. Such a change causes an error in the reflection brightness, which causes an error in the estimated emissivity, and ultimately results in a temperature measurement error. Therefore, in this embodiment, the temperature of the zinc-based hot-dip galvanized steel sheet SA1 was measured by measuring the surface shape of the zinc-based hot-dip galvanized steel sheet SA1 using the device shown in Figures 5(a) and (b) and correcting the specular reflection brightness and diffuse reflection brightness. In the device shown in FIGS. 5(a) and 5(b), a radiation thermometer 6 is used instead of the measuring device 1 of the device shown in FIG.

[0049] Specifically, first, as shown in FIG. 6, the steel sheet sample SA2 was placed on the reference surface, and the light source 11 was placed in the same manner as when the reflected luminance was actually measured. The steel sheet sample SA2 was moved in parallel in the vertical direction relative to the reference position using a vertical scanning mechanism 13 such as a linear slider or a jack, so that the displacement amount Δx could be adjusted, and the tilt amount Δθ could be adjusted by rotating the steel sheet sample SA2 relative to the reference angle using a rotation mechanism 14 such as a goniostage or a rotation stage. Next, the optical system under the regular reflection condition and the diffuse reflection condition was reproduced, and the reflected luminance was measured when the displacement amount Δx and the tilt amount Δθ of the steel sheet sample SA2 were changed using the camera 12. In detail, the maximum value of the expected displacement amount Δx was set to 30 mm, and the maximum value of the expected tilt amount Δθ was set to 4 degrees, and each reflected luminance was measured by changing the installation conditions of the steel sheet sample SA2 so as to cover the range. Note that, in the alloying process of zinc-based hot-dip coated steel sheet, the reflection state changes significantly due to the change in the surface property of the steel sheet. In detail, in the unalloyed state, the specular reflection luminance is important as shown in Fig. 7(a), but after alloying progresses to a certain extent, the specular reflection component almost disappears and only the diffuse reflection luminance becomes important as shown in Fig. 7(b). Therefore, the specular reflection luminance was measured on the unalloyed sample, and the diffuse reflection luminance was measured on the alloyed sample.

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

[0051] [Table 1]

[0052] The reflected light amount shown in Table 1 can be treated as a correction coefficient for the specular reflection luminance by normalizing it so that the light amount on the reference surface is 1. The obtained correction coefficient was fitted to formula (2) to model the relationship between the displacement amount Δx and tilt amount Δθ and the specular reflection luminance f(Δx, Δθ), and the following formula (7) was obtained.

[0053]

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[0054] Next, the radiation thermometer described in Patent Document 1 was installed at the measurement point of the zinc-based hot-dip galvanized steel sheet, and at the same time, a two-dimensional laser distance meter was installed at a position slightly away in the longitudinal direction so as not to interfere with the temperature measurement. From the output value obtained at the same timing as the measurement of the reflected luminance, the displacement amount Δx was calculated to be 15 mm, and the tilt amount Δθ was calculated to be 1 degree. Then, the specular luminance was corrected using the model calculated in advance in the modeling step and the displacement amount Δx and tilt amount Δθ obtained in the measurement step. When the displacement amount Δx and tilt amount Δθ are respectively 15 mm and 1 degree and substituted into the model formula, the value of the function f(Δx, Δθ) becomes 0.9929, and by dividing the obtained specular luminance by this value, it can be considered to be under the same conditions as the value measured at the position of the reference surface. By this correction, the specular luminance was calculated with high accuracy without being affected by the displacement amount Δx and tilt amount Δθ of the zinc-based hot-dip galvanized steel sheet SA1, and the temperature could be measured with high accuracy even if the shape of the zinc-based hot-dip galvanized steel sheet SA1 changed.

[0055] Regarding the specular reflection luminance, it is preferable to devise the type and installation position of the light source 11 so that the light emitting surface of the light source 11 is in the specular reflection direction under any condition within the range of the maximum value of the assumed displacement amount Δx and tilt amount Δθ of the zinc-based hot-dip galvanized steel sheet, and to always obtain a constant reflected light amount with respect to the change in the displacement amount Δx and tilt amount Δθ of the zinc-based hot-dip galvanized steel sheet. Specifically, as shown in FIG. 8(a), when the light source is a point light source 11a, the specular reflection condition is not established depending on the tilt of the zinc-based hot-dip galvanized steel sheet, and the reflected light amount measured by the camera 12 decreases. On the other hand, as shown in FIG. 8(b), when the light source is a line light source 11b, even if the zinc-based hot-dip galvanized steel sheet is tilted, the specular reflection condition is established somewhere on the light emitting surface, so the reflected light amount measured by the camera 12 does not decrease. In this way, by elongating the light source in the assumed tilt direction of the zinc-based hot-dip galvanized steel sheet and further uniformizing the light emission amount and directivity at each position on the light emitting surface, an optical system that stably achieves the specular reflection condition even if the position and tilt of the surface of the zinc-based hot-dip galvanized steel sheet change can be realized.

[0056] Although the embodiments of the present invention have been described above, the present invention is not limited by the descriptions and drawings that form part of the disclosure of the present invention according to the present embodiments. In other words, other embodiments, examples, and operation techniques, etc., made by those skilled in the art based on the present embodiments are all included in the scope of the present invention. [Explanation of symbols]

[0057] 1. Measurement equipment 2. Two-dimensional laser range finder 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 Camera 13 Up and down scanning mechanism 14 Rotation mechanism 31 Calculation section M Models P Measurement point S Strip-shaped object SA1 Zinc-based hot-dip coated steel sheet SA2 steel plate sample

Claims

1. A method for measuring a physical quantity of a surface of a strip-like object, the method comprising: a measuring step of measuring a displacement amount and a tilt amount of the belt-like object with respect to a reference plane around a measurement point; a correction step of correcting the measurement value of the physical quantity at the measurement point by using a pre-constructed model and the displacement amount and tilt amount measured in the measurement step; Including, the model indicates a relationship between a displacement amount and a tilt amount of the belt-like object with respect to a reference plane at the measurement point and a measurement value of the physical quantity at the measurement point; A method for measuring physical quantities on the surface of a strip-shaped object.

2. 2. A method for measuring physical quantities of a surface of a strip-like object as described in claim 1, wherein the measuring step includes a step of measuring the displacement and tilt of the strip-like object by measuring a shape profile of the surface of the strip-like object using a two-dimensional laser range finder.

3. 2. The method for measuring physical quantities of a surface of a strip-like object as described in claim 1, wherein the measurement step includes a step of measuring the displacement and inclination of the strip-like object by using a plurality of spot laser rangefinders to measure the displacement amount of the strip-like object at two or more points that are on a straight line extending in the width direction of the strip-like object and that sandwich the measurement point.

4. 2. A method for measuring a physical quantity on the surface of a strip-like object as described in claim 1, comprising a step of acquiring information regarding the distribution of the physical quantity in the width direction of the strip-like object by repeatedly executing the measurement step and the correction step while moving the measurement point along the width direction of the strip-like object.

5. A physical quantity measuring device for a surface of a strip-like object, the physical quantity being measured on the surface of the strip-like object being transported in a longitudinal direction, comprising: a measuring means for measuring the amount of displacement and the amount of inclination of the belt-like object relative to a reference plane around a measurement point; a correction means for correcting a measurement value of the physical quantity at the measurement point by using a model and the displacement amount and the tilt amount measured by the measurement means; Equipped with the model indicates a relationship between a displacement amount and a tilt amount of the belt-like object with respect to a reference plane at the measurement point and a measurement value of the physical quantity at the measurement point; A device for measuring physical quantities on the surface of a strip-shaped object.

6. A method for controlling the shape of a band-like object, comprising a step of controlling the shape of the band-like object based on physical quantities of the surface of the band-like object measured using a method for measuring physical quantities of the surface of a band-like object described in any one of claims 1 to 4.

7. A method for manufacturing a steel plate, comprising a step of controlling manufacturing conditions of the steel plate based on physical quantities of the surface of the steel plate measured using the method for measuring physical quantities of a surface of a belt-like object according to any one of claims 1 to 4.

8. The physical quantity measuring device for a surface of a belt-shaped object according to claim 5 ; a facility 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 the belt-like object; The steel plate manufacturing facility is equipped with:

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