Plate end portion detection device and plate end portion detection method

Abstract

The plate end detection device has one or more magnetic field generating portions that generate a magnetic field, disposed in a space generated between two adjacent conveying rollers and a path through which a steel plate passes; a plurality of detection portions arranged in a width direction of the plate end detection device corresponding to a plate width direction of the steel plate, detecting a signal corresponding to a strength of a magnetic field obtained by reflecting an influence of the steel plate in the magnetic field generated by the magnetic field generating portion; and an arithmetic processing portion that detects a position of a plate end of the steel plate, the arithmetic processing portion obtains a relationship between a change amount f of the signal detected by each detection portion and a position x of each detection portion in the width direction, approximates the obtained relationship using a function f(x), and detects a position x0 calculated according to the following formula (1) as the position of the plate end of the steel plate, f(x0)=Lmin+α×(Lmax-Lmin) … (1) Here, Lmax is a maximum value of the function f(x), Lmin is a minimum value of the function f(x), and α is a coefficient determined in advance.

Description

Technical Field

[0001] This disclosure relates to a plate end detection device and a plate end detection method. Background Technology

[0002] For example, a cooling device for cooling steel plates is equipped with multiple conveyor rollers, and the steel plates are conveyed within the cooling device while being placed on these rollers. During conveying, the steel plates may sometimes swerve due to thermal expansion of the conveyor rollers, poor flatness of the steel plates, etc. To suppress this swerving, for example, conveyor roller position control is implemented to change the position of the conveyor rollers. To perform conveyor roller position control, it is required to accurately detect the position of the ends of the steel plates in the width direction (hereinafter referred to as "plate ends").

[0003] Here, as a technique for detecting the position of the end of a steel sheet, the following technique is proposed. For example, Japanese Patent Application Publication No. 2009-250898 (Patent Document 1) discloses the following technique: while illuminating the surface of a coil on which a steel sheet is wound, the surface of the coil is photographed, and the position of the end of the coil is detected based on the brightness of the photographed image.

[0004] In addition, Japanese Patent Application Publication No. 55-147373 (Patent Document 2) discloses the following technology: using a sensor having a ferrite having three protrusions on the top and bottom, a reference coil, and a detection coil, the position of the end of a steel plate is detected based on the change in inductance of the detection coil when the reference coil generates a magnetic field, wherein the reference coil is wound around the protrusion in the center of the upper side of the ferrite, and the detection coil is wound around the protrusion in the center of the lower side of the ferrite. Summary of the Invention

[0005] The problem that the invention aims to solve However, the cooling device used to cool the steel plate is an environment where visible light and infrared light are blocked by water vapor and a large amount of water. Therefore, it is difficult to obtain an image with sufficient brightness to detect the position of the steel plate's end within such an environment. Consequently, it is difficult to detect the position of the steel plate's end while it is being transported within the cooling device using the technology described in Patent Document 1.

[0006] In contrast, the magnetic field is not affected by water vapor, large amounts of water, etc. Therefore, as described in Patent Document 2, when the position of the end of the steel plate is detected based on the change in inductance of the detection coil when the reference coil generates a magnetic field, it is possible to avoid the influence of water vapor, large amounts of water, etc.

[0007] However, when the steel plate is conveyed while mounted on the conveyor rollers, in addition to the change in the position of the plate end along the width direction of the steel plate, the steel plate also moves up and down (i.e., the passage line of the steel plate moves up and down). In the technology described in Patent Document 2, the change in inductance of the detection coil when the steel plate floats off the conveyor rollers is not considered, in addition to the change in the position of the steel plate end along the width direction. Therefore, the change in inductance obtained when the steel plate floats off the conveyor rollers is mistakenly interpreted as a change in inductance caused by the change in the position of the steel plate end along the width direction, thus making it impossible to accurately detect the position of the steel plate end when the steel plate floats off the conveyor rollers.

[0008] Therefore, the purpose of this disclosure is to provide a plate end detection device and a plate end detection method that can accurately detect the position of the plate end of a steel plate in an environment where visible light and infrared light are blocked by water vapor and a large amount of water in a cooling device for cooling the steel plate, without being affected by the up-and-down movement of the steel plate during transport as can be expected in normal manufacturing.

[0009] Methods for solving problems The first aspect of this disclosure is a plate end detection device that detects the position of the plate end of a steel plate within a cooling device for cooling a steel plate. The plate end detection device includes: one or more magnetic field generating units that generate a magnetic field and are disposed in the space created between two adjacent conveying rollers of a plurality of conveying rollers that convey the steel plate and the path through which the steel plate passes; a plurality of detection units arranged in a width direction corresponding to the width direction of the plate end detection device, detecting a signal corresponding to the strength of the magnetic field obtained by reflecting the influence of the steel plate in the magnetic field generated by the magnetic field generating units; and a processing unit that detects the position of the plate end of the steel plate based on the change amount f of the signal detected by each of the detection units and the position x of each of the detection units in the width direction. The processing unit obtains the relationship between the change amount f of the signal detected by each of the detection units and the position x of each of the detection units in the width direction, approximates the relationship using a function f(x), and detects the position x0 calculated according to the following equation (1) as the position of the plate end of the steel plate. f(x0)=Lmin+α×(Lmax-Lmin)…(1) Here, Lmax is the maximum value of the function f(x), Lmin is the minimum value of the function f(x), and α is a predetermined coefficient.

[0010] The second aspect of this disclosure is a plate end detection method, which detects the position of the plate end of a steel plate within a cooling device for cooling a steel plate. This plate end detection method uses a plate end detection device comprising: one or more magnetic field generating units that generate a magnetic field and are disposed in the space created between two adjacent conveying rollers of a plurality of conveying rollers conveying the steel plate and the path through which the steel plate passes; a plurality of detection units arranged in a width direction corresponding to the width direction of the plate end detection device, detecting a signal corresponding to the strength of the magnetic field obtained by reflecting the influence of the steel plate in the magnetic field generated by the magnetic field generating units; and a processing unit that, based on the change amount f of the signal detected by each of the detection units and the position of each of the detection units in the width direction... The method for detecting the end position of the steel plate includes: a detection step, which uses multiple detection units to detect a signal corresponding to the strength of a magnetic field generated by a magnetic field generating unit that reflects the influence of the steel plate; and a calculation processing step, which uses the calculation processing unit to detect the end position of the steel plate based on the change amount f of the signal detected by each detection unit and the position x of each detection unit in the width direction. In the calculation processing step, the relationship between the change amount f of the signal detected by each detection unit and the position x of each detection unit in the width direction is obtained, and the relationship is approximated using a function f(x). The position x0 calculated according to the following formula (1) is detected as the end position of the steel plate. f(x0)=Lmin+α×(Lmax-Lmin)…(1) Here, Lmax is the maximum value of the function f(x), Lmin is the minimum value of the function f(x), and α is a predetermined coefficient.

[0011] Invention Effects According to this disclosure, a plate end detection device and a plate end detection method are provided. In an environment where visible light and infrared light are blocked by water vapor and a large amount of water in a cooling device for cooling steel plates, the position of the plate end of the plate can be accurately detected without being affected by the up-and-down movement of the steel plate during transport as can be expected in normal manufacturing. Attached Figure Description

[0012] Figure 1 This is a top view showing the overall structure of the plate end detection device according to the first embodiment of the present disclosure and an example of a steel plate conveyed by multiple conveying rollers.

[0013] Figure 2 This is a side view showing an example of the overall structure of the plate end detection device of the first embodiment and a steel plate.

[0014] Figure 3This is a perspective view showing an example of a plurality of sensors in the first embodiment.

[0015] Figure 4 This is a front view showing an example of the structure of the sensor according to the first embodiment.

[0016] Figure 5 This is a diagram illustrating an example of the relationship between the change in inductance and the position of the sensor.

[0017] Figure 6 This is a diagram illustrating the relationship between the detection error of the end position of the test steel plate when it is horizontal and the amount of buoyancy of the test steel plate.

[0018] Figure 7 This is a block diagram illustrating an example of the structure of the processing apparatus according to the first embodiment.

[0019] Figure 8 This is a flowchart illustrating an example of the plate end detection process in the first embodiment.

[0020] Figure 9 This is a diagram illustrating the relationship between the change in inductance and the position of the sensor when the test steel plate is tilted.

[0021] Figure 10 This is an example illustrating the relationship between the detected position of the plate end and the number of times the starting point is shifted at each position of the sensor.

[0022] Figure 11 This is a perspective view showing an example of the sensor according to the fourth embodiment. Detailed Implementation

[0023] [First Implementation Method] First, the first embodiment of this disclosure will be described.

[0024] Figure 1 and Figure 2The overall structure of the plate end detection device 10 according to the first embodiment of this disclosure and an example of a steel plate 14 conveyed by a plurality of conveying rollers 12 are shown. For example, a plurality of conveying rollers 12 arranged in a horizontal direction are provided in a cooling device 16 for cooling the steel plate 14. The plurality of conveying rollers 12 are arranged parallel to each other. The steel plate 14 is conveyed in the cooling device 16 in a state of being placed on the plurality of conveying rollers 12. The X-axis direction represents the width direction of the steel plate 14, and the Y-axis direction represents the conveying direction of the steel plate 14. Hereinafter, the conveying direction of the steel plate 14 is referred to as the "conveying direction", and the width direction of the steel plate 14 is referred to as the "plate width direction". In addition, the width direction of the plate end detection device 10 is referred to as the "device width direction". The device width direction is the direction corresponding to the plate width direction. The device width direction refers to the direction orthogonal to the conveying direction when viewed from the normal direction of the surface of the steel plate 14.

[0025] In addition, Figure 1 and Figure 2 In this process, the steel plate 14 is conveyed in a horizontal direction, but the conveying direction is not limited to the horizontal direction. The steel plate 14 can also be conveyed in a direction other than the horizontal direction, such as the vertical direction. For convenience, the following description will continue to assume that the steel plate 14 is conveyed in a horizontal direction.

[0026] The plate end detection device 10 is a device for detecting the plate end (i.e., plate end 14A) of the steel plate 14 being conveyed in the cooling device 16, and has multiple sensors 18 and a processing device 20.

[0027] Multiple sensors 18 are arranged in the width direction of the device in the space created between adjacent conveyor rollers 12 and the path through which the steel plate 14 passes. The structure of each sensor 18 will be described in detail later. (Refer to...) Figure 3 and Figure 4 The sensor 18 is a non-contact magnetic sensor having a yoke 24, an excitation coil 26, and a detection coil 28. The sensor 18 is mounted on the stand 22 such that when the steel plate 14 is directly above the sensor 18, the magnetic flux emitted from the yoke 24 reaches the steel plate 14. However, the sensor 18 is positioned at a certain distance from the steel plate 14 for heat resistance and impact resistance. Multiple sensors 18 include sensors located outside the steel plate 14 even when conveying a steel plate 14 of maximum width that can be conveyed within the cooling device 16. Furthermore, although it also depends on the minimum width of the steel plate 14 that can be conveyed within the cooling device 16 (i.e., the steel plate being measured by the plate end detection device 10), the sensor 18 may not be positioned near the center of the plate end detection device 10 in the device width direction. Figure 1 and Figure 2In the example shown, as one instance, the plurality of sensors 18 include sensors 18 located inside the minimum width of the steel plate 14. The excitation coil 26 is an example of the magnetic field generating part of this disclosure, and the detection coil 28 is an example of the detection part of this disclosure.

[0028] The processing device 20 is electrically connected to a plurality of sensors 18 respectively, and applies voltage to the excitation coil 26, or detects the position of the end of the steel plate 14 based on the signal detected by the detection coil 28 in accordance with the strength of the magnetic field generated by the excitation coil 26.

[0029] Figure 3 This represents an example of multiple sensors 18 arranged along the width of the device. Figure 4 This illustrates an example of the structure of each sensor 18. Multiple sensors 18 have the same structure. Each sensor 18 has a magnetic yoke 24, an excitation coil 26, a detection coil 28, and a pair of winding tubes 30. The magnetic yoke 24 is made of a magnetic material such as a ferrite core, and has a pair of core portions 32 and a connecting portion 34. The pair of core portions 32 extend in the vertical direction, and the connecting portion 34 connects the lower ends of the pair of core portions 32 to each other.

[0030] Each winding tube 30 is formed in a cylindrical shape. Each winding tube 30 is mounted on a core 32 by inserting a core 32 into the inside of each winding tube 30. The excitation coil 26 is wound around the core 32 of one of the pairs of cores 32 via the winding tube 30, and the detection coil 28 is wound around the core 32 of the other of the pairs of cores 32 via the winding tube 30.

[0031] The magnetic yoke 24 functions as a strongly magnetic core material for both the excitation coil 26 and the detection coil 28. Each magnetic yoke 24 is arranged with a pair of cores 32 aligned in the transport direction. Furthermore, multiple magnetic yokes 24 are arranged in a configuration that spans the width of the device. The detection coil 28 provided on each magnetic yoke 24 corresponds to the excitation coil 26 provided on the same sensor 18.

[0032] In sensor 18, the excitation coil 26 and the detection coil 28 are composed of different coils, which can be independently wound in each core 32, or a single coil can be continuously wound in each core 32 as both the excitation coil 26 and the detection coil 28. Hereinafter, as an example, the sensor 18 will be further explained using a structure in which a single coil is continuously wound in each core 32 as both the excitation coil 26 and the detection coil 28.

[0033] When the steel plate 14 is not present on the sensor 18, the magnetic flux emitted from the yoke 24 on which the excitation coil 26 is mounted is drawn into the S pole of the yoke 24 on which the detection coil 28 is mounted on the same sensor 18. On the other hand, when the steel plate 14 is present on the sensor 18, eddy currents are generated due to the time-varying magnetic flux. These eddy currents generate a magnetic field that cancels out the magnetic flux emitted from the yoke 24 on which the excitation coil 26 is mounted. The spatial distribution of the magnetic flux is canceled out by the eddy currents generated by the presence of the steel plate 14 as a conductor, thereby causing a change in the strength of the magnetic field detected by the detection coil 28. Utilizing this phenomenon, a signal corresponding to the strength of the magnetic field reflected by the steel plate 14 in the magnetic field generated by the excitation coil 26 is obtained at each position of the sensor 18, and the position of the end of the steel plate 14 can be detected based on the relationship between the amount of change in the obtained signal and the position of the sensor 18. Furthermore, the signal corresponding to the strength of the magnetic field can be represented by electromagnetic characteristics such as impedance (inductance), voltage, and current. The following explanation uses an inductor as an example of a signal corresponding to the strength of a magnetic field.

[0034] Figure 5 This example illustrates the relationship between the change in inductance obtained through experimentation and analysis and the position of sensor 18. In the experiment, a test steel plate 36 was used as a substitute for steel plate 14, and multiple sensors 18 were arranged along the width of the device. Figure 5 In the diagram, the positions of the test steel plate 36 used in the experiment and the locations of the multiple sensors 18 are displayed corresponding to the horizontal axis of the graph. The vertical axis represents the value corresponding to the amplitude of the signal detected by the detection coil 28, specifically, the change in inductance depending on the relative position of the magnetic yoke 24 and the test steel plate 36. Figure 5 The left vertical axis, or the first vertical axis, represents the experimental values. Figure 5 The right-hand vertical axis, or second vertical axis, represents the analytical value. The horizontal axis represents the position of the sensor 18 disposed in the width direction of the device. The first and second vertical axes are examples of the first axis of this disclosure, and the horizontal axis is an example of the second axis of this disclosure. In addition, the position of the sensor 18 is an example of the position of the detection coil of this disclosure. Furthermore, in this disclosure, apart from the first embodiment, for the second and third embodiments, etc., in principle, only one side of the device width direction of the plate end detection device 10 is described for convenience, and the description of the opposite side of the device width direction of the plate end detection device 10 is omitted.

[0035] In the experiment, multiple sensors 18 were positioned at various plotted points along the width of the apparatus, from the outer side of the end of the test steel plate 36 towards the inner side. An AC voltage was applied to the excitation coil 26 of each sensor 18, and a signal (inductance) was detected by the detection coil 28 corresponding to the strength of the magnetic field generated by the excitation coil 26, reflecting the influence of the test steel plate 36. The relationship between the change in inductance and the position of the sensor 18 was then graphically represented. The plotted points, indicated by white circles, represent the measured values ​​obtained through the experiment. Curve G1 is a line smoothly connecting the experimental values ​​indicated by white circles for easy understanding of the experimental results.

[0036] On the other hand, in the analysis, software capable of simulating the strength and distribution of the magnetic field is used to represent the experimental steel plate 36 and multiple sensors 18 used in the experiment on a computer. The signal (inductance) detected by the detection coil 28 is obtained using the same method as in the experiment. Then, the relationship between the relative change in inductance and the position of the sensor 18 is graphically plotted. The plotted points, represented by black circles, represent the analytical values ​​obtained through analysis. Curve G2 is a line that smoothly connects the analytical values ​​represented by black circles to facilitate understanding of the analytical results.

[0037] The sensor 18, located sufficiently far from the end of the test steel plate 36 towards the outside of the test steel plate 36, can detect the signal without the magnetic flux emitted from the magnetic yoke 24 being blocked by the test steel plate 36. Therefore, the values ​​of the vertical axes of curves G1 and G2 remain at their upper limits. The value of the vertical axis that maintains this upper limit can be considered as the upper limit. That is, the value considered as the upper limit here refers to... Figure 5 The relationship between the change in inductance and the position of sensor 18 is shown in the diagram, where the vertical axis reaches its maximum value at saturation. As the sensor 18 moves from the outer side of the test steel plate 36 towards its end, the amount of magnetic flux blocked by the test steel plate 36 gradually increases, thus decreasing the values ​​of the vertical axes of curves G1 and G2. When the sensor 18 moves past the end of the test steel plate 36 towards its inner side, the amount of magnetic flux blocked by the test steel plate 36 further increases, thus further decreasing the values ​​of the vertical axes of curves G1 and G2. Furthermore, for the sensor 18 located inside the test steel plate 36, the magnetic flux emitted from the yoke 24 is blocked by the test steel plate 36, so the values ​​of the vertical axes of curves G1 and G2 remain unchanged at their lower limits. The value of the vertical axis that maintains this lower limit can be considered as the lower limit. That is, the value considered as the lower limit here refers to... Figure 5 The relationship between the change in inductance and the position of sensor 18 is shown in the figure, with the minimum value of the vertical axis when saturation occurs.

[0038] Here, the inventors believe that the experimental and analytical results (curves G1 and G2) can be approximated as functions. By approximating as a function, values ​​considered as upper limits and lower limits can be detected without being affected by noise. Examples of such functions include the Sigmoid function and the Ramp function. Furthermore, other functions capable of representing saturated distributions with maximum and minimum values ​​can also be used. Hereinafter, the Sigmoid function will be used as an example. The Sigmoid function is an example of the functions disclosed herein.

[0039] Furthermore, the inventors conducted multiple experiments and analyses by changing the position of the end of the test steel plate 36 in the width direction of the device, and performed tests on the end of the plate. The results showed that the position of the horizontal axis, which divides the range of values ​​considered as the upper limit and the range considered as the lower limit of the approximate vertical axis of the Sigmoid function into a predetermined ratio (hereinafter referred to as "segmentation ratio a:b"), corresponds to the position of the end of the test steel plate 36. For example, the segmentation ratio a:b is 3:7, but is not limited to this.

[0040] Furthermore, the inventors considered the vertical movement of the steel plate 14 during transport, as is typically conceivable in manufacturing, and conducted evaluation tests by changing the vertical position of the test steel plate 36 while keeping it horizontal. In this evaluation test, the following experiment was conducted: with the position of the end of the test steel plate 36 fixed in the width direction of the device, the buoyancy of the test steel plate 36 was varied, and the position of the end of the test steel plate 36 was measured five times for each buoyancy. In each test, the position of the horizontal axis, which divides the range of values ​​considered as the upper and lower limits of the vertical axis of the Sigmoid function obtained in the test into a division ratio a:b, was calculated as the position of the end of the test steel plate 36. The difference between the calculated end position and the reference position was taken as the detection error of the end position. Then, the average, maximum, and minimum values ​​of the detection error of the end position obtained in the five tests were calculated. Here, the amount of buoyancy refers to the amount by which the path of the test steel plate 36, which is in contact with the conveyor roller (without bouncing) and is conveyed, is defined as the plate-passing line, indicating how much the plate-passing line and the test steel plate 36 are separated in the vertical direction.

[0041] Figure 6 This is an example illustrating the relationship between the detection error of the position of the end of the test steel plate 36 and the amount of buoyancy of the test steel plate 36. For example... Figure 6As shown, if the vertical movement of the steel plate 14 during transport is within the range conceivable in normal manufacturing (for example, the float is 40 mm or less), the detection error can be brought within the allowable range (for example, ±5 mm or less). Furthermore, based on this evaluation test, the inventors found that even when the steel plate 14 moves horizontally up and down within the range conceivable in normal manufacturing, the aforementioned division ratio a:b remains approximately unchanged.

[0042] As can be seen from the above, for a steel plate 14 that moves horizontally up and down within the range of vertical movement during transport that can be conceived in normal manufacturing, the plate end detection device 10 is used to obtain the relationship between the change in the signal obtained at each position of the sensor 18 and the position of the sensor 18. The obtained relationship is approximated using the Sigmoid function, and the position of the horizontal axis is derived by dividing the range of values ​​considered as the upper limit and the lower limit of the vertical axis of the approximated Sigmoid function into a division ratio a:b. The position of the derived horizontal axis can be detected as the position of the plate end of the steel plate 14.

[0043] Furthermore, when the aforementioned segmentation ratio a:b is determined experimentally, it is assumed that the segmentation ratio a:b will vary slightly in each experiment as the position of the plate end changes in the width direction of the device. Therefore, it is also possible to perform multiple experiments by changing the position of the plate end in the width direction of the device, calculate the average of the multiple segmentation ratios a:b obtained in each experiment, and use the calculated segmentation ratio a:b when actually detecting the position of the plate end of the steel plate 14. Similarly, when the aforementioned segmentation ratio a:b is determined analytically, it is assumed that the aforementioned segmentation ratio a:b will vary slightly in each analysis as the position of the plate end changes in the width direction of the device. Therefore, it is also possible to perform multiple analyses by changing the position of the plate end in the width direction of the device, calculate the average of the multiple segmentation ratios a:b obtained in each analysis, and use the calculated segmentation ratio a:b when actually detecting the position of the plate end of the steel plate 14. Hereinafter, the segmentation ratio a:b predetermined by calculating the average of multiple segmentation ratios a:b will be referred to as the "specific ratio".

[0044] Next, the specific structure of the processing apparatus 20 of the first embodiment will be described. Figure 7This illustrates an example of the structure of the processing device 20. The processing device 20 is a computer-based unit that performs various controls and calculations on the board-end detection device 10. The processing device 20 includes a processor 42, volatile memory 44, non-volatile memory 46, output circuitry 48, and input circuitry 50. The processor 42, volatile memory 44, non-volatile memory 46, input circuitry 50, and output circuitry 48 are interconnected via a bus 52 or similar means, enabling them to communicate with each other.

[0045] The processor 42 may be a CPU (Central Processing Unit) or an MPU (Microprocessor Unit). The volatile memory 44 may be RAM (Random Access Memory) or similar, serving as a temporary storage area for programs and data. The non-volatile memory 46 may be ROM (Read-Only Memory), HDD (Hard Disk Drive), or SSD (Solid State Drive), storing various programs, including the operating system, and various types of data.

[0046] The non-volatile memory 46 stores a program for performing the processing of detecting the position of the end of the steel plate 14 (hereinafter referred to as "plate end detection processing"). The processor 42 reads the program from the non-volatile memory 46 and executes the program using the volatile memory 44 as the working area. The processor 42 controls the output circuit 48 according to the program stored in the non-volatile memory 46, or performs calculations based on the signals input from the input circuit 50.

[0047] Alternatively, the processing device 20 can replace the processor 42 or incorporate electronic circuits such as a PLD (Programmable Logic Device) or an ASIC (Application Specific Integrated Circuit) based on the processor 42. Furthermore, some or all of the functions of the processor 42 can also be implemented using electronic circuits such as a PLD or ASIC.

[0048] The output circuit 48 is electrically connected to the excitation coils 26 of each sensor 18. The output circuit 48 is controlled by the processor 42, thereby applying voltage to each excitation coil 26. The input circuit 50 is electrically connected to the detection coils 28 of each sensor 18. When the signal output from the detection coil 28 is input to the input circuit 50, the input circuit 50 converts the analog signal output from the detection coil 28 into a digital signal using an A / D converter, and outputs the digitized signal to the processor 42.

[0049] The processor 42 reads the program for performing board end detection processing from the non-volatile memory 46, expands the read program in the volatile memory 44 and executes it, thereby performing the functions of each functional unit of the processing device 20. Specifically, the processor 42 functions as the voltage control unit 62 and the arithmetic processing unit 66.

[0050] The voltage control unit 62 is a functional unit that controls the application of voltage to the excitation coils 26 of the multiple yokes 24 by the output circuit 48. When the voltage control unit 62 applies an AC voltage to the excitation coils 26, the signal corresponding to the strength of the magnetic field in the magnetic field generated by the excitation coils 26, which reflects the influence of the steel plate 14, is detected by the detection coil 28 provided on the same sensor 18.

[0051] The processing unit 66 detects the position of the end of the steel plate 14 based on the relationship between the change in signal detected by all the detection coils 28 and the position of the sensor 18. Specifically, the processing unit 66 acquires a signal detected by the detection coils 28 at each position of the sensor 18, corresponding to the strength of the magnetic field obtained by reflecting the influence of the steel plate 14 in the magnetic field generated by the excitation coil 26. For example, multiple channels for signal input from each detection coil 28 are provided in the input circuit 50. The position of each sensor 18 is assigned to each channel. When the processing unit 66 acquires a signal from each channel, it determines the position of the sensor 18 corresponding to each signal based on the identification information of each channel. Then, the processing unit 66 approximates the relationship between the change in signal acquired at each position of the sensor 18 and the position of the sensor 18 using a Sigmoid function, and detects the position of the horizontal axis, which is divided into the range of values ​​considered as the upper limit and the lower limit of the vertical axis of the approximate Sigmoid function by the aforementioned predetermined specific proportion, as the position of the end of the steel plate 14.

[0052] For example, the arithmetic processing unit 66 can also detect the position of the end of the steel plate 14 by performing the following arithmetic processing. That is, the arithmetic processing unit 66 can also obtain the relationship between the change amount f of the signal detected by each detection coil 28 and the position x of each detection coil 28 in the width direction of the device, approximate the obtained relationship with the Sigmoid function f(x), and detect the position x0 calculated according to the following formula (1) as the position of the end of the steel plate 14.

[0053] f(x0)=Lmin+α×(Lmax-Lmin)…(1) Here, Lmax is the maximum value of the sigmoid function f(x). The maximum value Lmax can also be considered as the upper limit among the values ​​on the vertical axis of the sigmoid function described above, for example, in... Figure 5 The relationship between the change in inductance and the position of sensor 18 is shown in the figure, with the maximum value of the vertical axis when saturation occurs.

[0054] Additionally, Lmin is the minimum value of the sigmoid function f(x). The minimum value Lmin can also be considered as the lower limit among the values ​​on the vertical axis of the sigmoid function described above, for example, in... Figure 5 The relationship between the change in inductance and the position of sensor 18 is shown in the figure, with the minimum value of the vertical axis when saturation occurs.

[0055] Furthermore, α is a predetermined coefficient. The coefficient α is the ratio corresponding to the specific proportion mentioned above, and is α = b / (a + b).

[0056] Alternatively, the coefficient α can be pre-stored in the volatile memory 44 or the non-volatile memory 46. The coefficient α can also be pre-stored in the volatile memory 44 or the non-volatile memory 46 by having the user input the value of α to the processing device 20 using the board-end detection device 10. Furthermore, the arithmetic processing unit 66 can also retrieve the coefficient α pre-stored in the volatile memory 44 or the non-volatile memory 46. The volatile memory 44 or the non-volatile memory 46 is an example of the "storage unit" of this disclosure.

[0057] The coefficient α is a coefficient set using a test steel plate, which is used as a substitute for the steel plate 14, based on a specific coefficient setting process. The coefficient setting process uses the test steel plate to obtain the relationship between the change in signal f detected by each detection coil 28 and the position x of each detection coil 28 in the width direction of the device. This relationship is approximated by a Sigmoid function f(x). The actual position x0' of the end of the test steel plate is input into the Sigmoid function f(x) to calculate the value of the function f(x0'). Then, α, calculated by substituting the values ​​of the function f(x0'), the maximum value Lmax, and the minimum value Lmin of the function f(x) into the following equation (1'), is set as the coefficient.

[0058] α=(f(x0')-Lmin) / (Lmax-Lmin)…(1') That is, using a test steel plate, the relationship between the change in signal f detected by each detection coil 28 and the position x of each detection coil 28 in the width direction of the device is obtained. This relationship is approximated by a Sigmoid function f(x). The actual position x0' of the end of the test steel plate is input into the Sigmoid function f(x) to calculate the value of the function f(x0'). Then, the process includes: determining the ratio a:b when dividing the range of the maximum and minimum values ​​of the Sigmoid function f(x) using the value of the function f(x0'); obtaining multiple ratios a:b obtained by changing the position of the end of the test steel plate in the width direction of the device relative to the positions of the multiple detection coils 28; and setting a coefficient α based on the multiple ratios a:b. For example, the coefficient α can also be set by calculating the average of the multiple ratios a:b and obtaining the ratio b / (a+b) based on the calculated ratios a:b. For example, as described above, when the average value of the ratios a:b is 3:7, α is set to 0.70. The value of α is a characteristic inherent to each plate end detection device 10. The value of α depends not only on the inherent characteristics of the sensor 18 (magnetic properties, etc.) and the spacing between the sensor 18 and the steel plate 14 (including a test steel plate used as a substitute for the steel plate 14), but also on the type of signal used (e.g., impedance (inductance), voltage, and current, etc.). Therefore, the value of α needs to be set during the coefficient setting process for each plate end detection device 10. As needed, the coefficient setting process can also be performed periodically for each plate end detection device 10 to set the value of α. Furthermore, the value of α is often approximately 0.70, i.e., within the range of 0.60 to 0.80.

[0059] Figure 8 An example of the flow of board end detection processing executed by the processor 42 of the processing device 20 is shown. The board end detection process is executed by the processor 42, thereby executing the board end detection method of the board end detection device 10.

[0060] First, in step S10, the voltage control unit 62 controls the voltage applied to the excitation coils 26 of the plurality of yokes 24. Specifically, the voltage control unit 62 selects a yoke 24 from the plurality of yokes 24 and controls the application of an AC voltage to the excitation coil 26 of the selected yoke 24.

[0061] Next, in step S12, when an AC voltage is applied to the excitation coil 26 of the corresponding yoke 24, the detection coil 28 detects a signal corresponding to the strength of the magnetic field obtained in the magnetic field generated by the excitation coil 26, which reflects the influence of the steel plate 14. Step S12 is an example of the detection step of this disclosure.

[0062] Next, in step S14, the arithmetic processing unit 66 detects the position of the end of the steel plate 14 based on the relationship between the change in the signal detected by the detection coil 28 and the position of the sensor 18. Specifically, the arithmetic processing unit 66 acquires a signal detected by the detection coil 28 corresponding to the strength of the magnetic field reflected by the steel plate 14 in the magnetic field generated by the excitation coil 26 at each position of the sensor 18, and uses a Sigmoid function to approximate the relationship between the acquired signal change and the position of the sensor 18. Then, the arithmetic processing unit 66 detects the position of the horizontal axis, which is divided into the range of values ​​considered as the upper limit and the lower limit of the vertical axis of the approximate Sigmoid function by the aforementioned predetermined specific proportion, as the position of the end of the steel plate 14. The arithmetic processing unit 66 can also detect the position of the end of the steel plate 14 by performing the above-described arithmetic processing. After step S14, the end plate detection processing ends. Step S14 is an example of the arithmetic processing steps of this disclosure.

[0063] As explained above, in the plate end detection device 10 of the first embodiment, the arithmetic processing unit 66 acquires a signal detected by the detection coil 28 at each position of the sensor 18, corresponding to the strength of the magnetic field obtained by reflecting the influence of the steel plate 14 in the magnetic field generated by the excitation coil 26. A sigmoid function is used to approximate the relationship between the change in the acquired signal and the position of the sensor 18. Then, the arithmetic processing unit 66 detects the position of the horizontal axis, which divides the range of values ​​considered as the upper and lower limits of the vertical axis of the approximate sigmoid function into the aforementioned predetermined specific proportions, as the position of the plate end of the steel plate 14.

[0064] Here, the specific proportions mentioned above, based on the inventors' research, show that within the range of vertical movement of the steel plate 14 during transport that can be conceived in normal manufacturing, they remain approximately unchanged even if the steel plate 14 remains horizontally moving up and down (see reference). Figure 6 Therefore, even if the steel plate 14 moves up and down during transport within the range that can be expected during normal manufacturing, the position of the end of the steel plate 14 can be accurately detected without being affected by the up and down movement of the steel plate 14.

[0065] Furthermore, in the plate end detection device 10 of the first embodiment, a magnetic field unaffected by water vapor, large amounts of water, etc., is used to detect the position of the plate end of the steel plate 14. Therefore, when detecting the position of the plate end of the steel plate 14, the influence of water vapor, large amounts of water, etc., can be avoided.

[0066] Thus, according to the plate end detection device 10 of the first embodiment, in an environment where visible light and infrared light are blocked by water vapor, a large amount of water, etc., such as in the cooling device 16 that cools the steel plate 14, the position of the plate end of the steel plate 14 can be accurately detected without being affected by the up-and-down movement of the steel plate 14 during transport, which is conceivable in normal manufacturing.

[0067] In addition, Figure 5 In the chart shown, since inductance is used as the detected signal, the relationship between the vertical and horizontal axes is represented as the value of the vertical axis decreases as the value of the horizontal axis increases. However, based on the calculation method of the vertical axis value (including changing the detected object to voltage or current), we can also assume that the value of the vertical axis increases as the value of the horizontal axis increases (in other words, Figure 5 (The graph is displayed upside down). Even in this case, the arithmetic processing unit 66 can set the maximum value Lmax to the value considered as the upper limit in the vertical axis of the Sigmoid function, that is, for example, the maximum value when the vertical axis is saturated, and can also set the minimum value Lmin to the value considered as the lower limit in the vertical axis of the Sigmoid function, that is, the minimum value when the vertical axis is saturated.

[0068] [Second Implementation] Next, the second embodiment of this disclosure will be described. Content that is repeated in the first embodiment will be omitted from the description using the same terminology.

[0069] In the first embodiment described above, the steel plate 14 is assumed to move up and down while remaining horizontal. However, in normal manufacturing, it is envisioned that the steel plate 14 is tilted relative to the width direction of the device when viewed from the conveying direction. According to the first embodiment, even when the steel plate 14 is tilted, the position of the end of the steel plate 14 can be detected with a certain degree of accuracy, but it is also envisioned that higher detection accuracy is required. In the second embodiment, compared with the first embodiment, the aim is to improve the detection accuracy when detecting the position of the end of the steel plate 14.

[0070] Figure 9 This example illustrates the relationship between the change in inductance obtained through experimentation and the position of sensor 18. In the experiment, inclined test steel plates 36A and 36B were used as replacements for steel plate 14. Figure 9 In the diagram, the inclined test steel plates 36A and 36B and multiple sensors 18 are shown corresponding to the horizontal axis of the graph.

[0071] The test steel plate 36A is tilted relative to the reference height of the through line with a float of 0 mm at the end of the plate and the float increases in a gradient of 8 / 120 toward the inside of the test steel plate 36A.

[0072] The test steel plate 36B is positioned relative to the reference height of the through-plate line, with a float of 30 mm at the end of the plate, and the float is tilted towards the inside of the test steel plate 36B in a gradient decreasing in the order of 8 / 120.

[0073] The height L1 from the reference height of sensor 18 to the reference height of the conveyor line is set to 30 mm. The lift-off amount L represents the distance of the steel plate 14 or test steel plate 36 at a specific location in the width direction of the device from the reference height of sensor 18. That is, the lift-off amount L of each sensor 18 is defined as the value obtained by adding the value of the buoyancy to the value of the height L1 from the reference height of sensor 18 to the reference height of the conveyor line. The reference height of sensor 18 can also be the average of the heights of multiple sensors 18. The reference height of the conveyor line can also be the average of the entire length of the conveyor line that transports the steel plate 14.

[0074] The vertical axis represents the value corresponding to the amplitude of the signal obtained experimentally; specifically, it represents the relative change in inductance detected by the multiple sensors 18 positioned along the width of the device. The horizontal axis, relatively speaking, represents the position of the sensors 18 when a predetermined reference position along the width of the device is set to 0. The reference position is the position at the end of the plate, set in the experiment.

[0075] In the experiment, using the aforementioned plate end detection device 10, an AC voltage was applied to the excitation coil 26 of each sensor 18, and a signal (inductance) was detected by the detection coil 28 corresponding to the strength of the magnetic field generated by the excitation coil 26, which reflects the influence of the steel plate. Furthermore, the relationship between the change in inductance and the position of the sensor 18 was approximated using the Sigmoid function.

[0076] Curve A1 represents the change in inductance obtained for the test steel plate 36A and the position of sensor 18.

[0077] Curve A2 represents the change in inductance and the position of sensor 18 for a horizontally positioned test steel plate with a lift-off amount L of 30 mm.

[0078] Curve A3 represents the change in inductance and the position of sensor 18 for a horizontally positioned test steel plate with a lift-off amount L of 35 mm.

[0079] Curve A4 represents the change in inductance and the position of sensor 18 for a horizontally positioned test steel plate with a lift-off amount L of 40 mm.

[0080] Curve B1 represents the change in inductance obtained for the test steel plate 36B and the position of sensor 18.

[0081] Curve B2 represents the change in inductance and the position of sensor 18 for a horizontally positioned test steel plate with a lift-off amount L of 50 mm.

[0082] Curve B3 represents the change in inductance and the position of sensor 18 for a horizontally positioned test steel plate with a lift-off amount L of 60 mm.

[0083] Curve B4 represents the change in inductance and the position of sensor 18 for a horizontally positioned test steel plate with a lift-off of 70 mm.

[0084] Here, the inventors compared curve A1 with curves A2 to A4 and obtained the following insights: In the case of the inclined test steel plate 36A, within the range of the sensor 18 position from -70mm to 40mm, the change in inductance tends to change in the same manner as in the case of the test steel plate that remains horizontally floating. However, for the range where the sensor 18 position exceeds 40mm, the change in inductance deviates from the case of the test steel plate that remains horizontally floating. Furthermore, the inventors compared curve B1 with curves B2 to B4 and obtained the following insights: In the case of the inclined test steel plate 36B, within the range of the sensor 18 position from -70mm to 40mm, the change in inductance tends to change in the same manner as in the case of the test steel plate that remains horizontally floating. However, for the range where the sensor 18 position exceeds 40mm, the change in inductance deviates from the case of the test steel plate that remains horizontally floating.

[0085] Furthermore, based on the above insights, the inventors believe that in the case of an inclined steel plate 14, if data on the range R of the change in inductance that changes with the same tendency as in the case of a steel plate 14 that remains horizontally floating is used (in other words, if data on the range of the change in inductance that deviates from the case of a steel plate 14 that remains horizontally floating is not used), the effects of the inclination of the steel plate 14 can be mitigated, and the position of the end of the steel plate 14 can be detected.

[0086] Specifically, the inventors believe that the position of the sensor 18 located at the outermost point in the device width direction, where the value of the vertical axis is considered to be the upper limit, is the position of the sensor 18 located at the outermost point in the device width direction (e.g., in...). Figure 9 Starting from the point corresponding to -70mm, the point with the smallest vertical axis value is among the points along the path from the value considered the upper limit towards the lower limit, where the vertical axis value is unaffected even if the steel plate 14 tilts and the vertical axis value becomes the value considered the lower limit (e.g., in...). Figure 9The position of the sensor 18 corresponding to the point (corresponding to 40mm) is the endpoint. The position of the end of the steel plate 14 can be detected based on the change in inductance obtained from the sensor 18 that exists in the interval from the starting point to the endpoint among the multiple sensors 18.

[0087] Based on the above considerations, in the second embodiment, the arithmetic processing unit 66 operates as follows: The arithmetic processing unit 66 generates a graph having a vertical axis corresponding to the change in signal obtained at each position of the sensor 18 and a horizontal axis corresponding to the position of the sensor 18 (for example, refer to...). Figure 9 When the relationship between the change in signal corresponding to the strength of the magnetic field and the position of sensor 18, as shown in the diagram, is approximated by the Sigmoid function, the following intervals are sequentially set from the outside to the inside in the width direction of the device: the starting point is the position of sensor 18 located at the outermost point in the width direction of the device, where the value of the vertical axis is considered to be the upper limit; the ending point is the position of sensor 18 corresponding to the point where the vertical axis value is the smallest among the points where the vertical axis value decreases from the upper limit value towards the lower limit, even if the steel plate 14 is tilted, the vertical axis value is not affected, and the vertical axis value becomes the value considered to be the lower limit value. (For example, with...) Figure 9 The range R corresponds to the interval. Then, the arithmetic processing unit 66 detects the position of the end of the steel plate 14 based on the relationship between the change in the signal corresponding to the strength of the magnetic field obtained from the sensor 18 existing in the set interval and the position of the sensor 18. Specifically, the arithmetic processing unit 66 detects the position of the end of the steel plate 14 within the range corresponding to the set interval (e.g., Figure 9 The values ​​on the vertical axis of the range R are considered as the upper limit (e.g., in...). Figure 9 In the middle, the value corresponding to -70mm) and the value considered as the lower limit (e.g., in Figure 9 The range of values ​​corresponding to 40mm is divided into the positions of the horizontal axis at the predetermined specific proportions mentioned above, which serve as the plate ends of the steel plate 14.

[0088] More specifically, the arithmetic processing unit 66 can also detect the position of the end of the steel plate 14 by performing subsequent arithmetic processing. That is, the arithmetic processing unit 66 can also first predict the position of the end of the steel plate 14, and set the aforementioned interval (e.g., with the position of the end of the steel plate 14) in a manner that includes the position of the end of the steel plate 14. Figure 9 The range R corresponds to the interval. Furthermore, the arithmetic processing unit 66 can also detect the position of the end of the steel plate 14 based on the relationship between the change f of the signal detected by each detection coil 28 in the set interval and the position x of each detection coil.

[0089] The arithmetic processing unit 66 sets the aforementioned range (for example, with...). Figure 9In the case of the interval corresponding to the range R, the position of the end of the steel plate 14 can also be predicted by performing subsequent prediction processing (e.g., Figure 9 (The position where the horizontal axis value is 0).

[0090] For example, the arithmetic processing unit 66 may also use the Sigmoid function to approximate the relationship between the change in the signal obtained at each position of the sensor 18 and the position of the sensor 18, and detect the position of the horizontal axis that is divided into the range of values ​​considered as the upper limit and the lower limit of the vertical axis of the approximate Sigmoid function by the aforementioned predetermined specific proportion, as the position of the end of the steel plate 14, thereby predicting the position of the end of the steel plate 14. Thus, when an approximation based on the Sigmoid function is performed to predict the position of the inclined steel plate 14 (the approximation of the second embodiment of this application), it is preferable that after an approximation is performed in advance to predict the position of the steel plate 14 (for example, the approximation of the first embodiment, referred to as the first approximation for convenience), an approximation is performed based on the position of the steel plate 14 predicted by the Sigmoid function obtained through the first approximation to accurately detect the position of the steel plate 14 (even if the steel plate 14 is inclined) within the interval set in the second embodiment of this application (the interval from the first position x1 to the second position x2 described later).

[0091] Furthermore, the arithmetic processing unit 66 can also obtain the signal change from multiple sensors 18, determine whether the differential value of the signal change calculated from the outside to the inside of each adjacent sensor 18 in the width direction of the device exceeds a predetermined threshold, and predict the position of the sensor 18 located on the inside side of the width direction of the adjacent sensor 18 whose differential value exceeds the threshold as the position of the end of the steel plate 14. As this prediction method, the first approximation described above is not required, only the second approximation described above is used. Since there is no first approximation, the calculation time in the arithmetic processing unit 66 can be shortened.

[0092] In addition, the processing unit 66 can also obtain the signal changes from multiple sensors 18 and predict the position of the horizontal axis, which is divided into the range of values ​​considered as the upper limit and the lower limit in the vertical axis by the aforementioned predetermined specific proportion, as the position of the end of the steel plate 14. This prediction method does not require a first approximation, but only a second approximation, which can shorten the calculation time (operation time).

[0093] Regarding the length of the interval, for example, in a preliminary test using a test steel plate as a substitute for the steel plate, the first position x1 and the second position x2, as defined below, can be determined and set to a length equivalent to the distance from the first position x1 to the second position x2.

[0094] The first position x1 is located on the outer side of the device in the width direction, compared to the position x0 at the end of the plate, and corresponds to the position of the maximum value of the function f(x) obtained for the test steel plate in the preliminary test. The maximum value of the function f(x) can be either the value corresponding to the position of the outermost sensor 18 in the width direction of the device, which is considered as an upper limit, or the maximum value among the values ​​considered as an upper limit.

[0095] Furthermore, although it also depends on the function used, there are many cases where the position corresponding to the maximum value (Lmax) or minimum value (Lmin) of the function f(x) is infinitely far outside the device width direction. In this case, when determining the first position x1, the position of the outermost sensor 18 in the device width direction can also be regarded as the position corresponding to the maximum or minimum value of the function f(x). In addition, in order to shorten the calculation time (operation time) by reducing the number of sensors used as approximations, a value smaller (or larger) than the value of the function f(x) at the position of the outermost sensor 18 in the device width direction can be regarded as the maximum (or minimum) value of the function f(x). However, in this case, the permissible range from the value of the function f(x) at the position of the outermost sensor 18 in the device width direction to a value that is small (or large) can be regarded as the maximum (or minimum) value of the function f(x) is determined in advance through preliminary tests, magnetic analysis, etc., based on the required prediction accuracy of the plate end position and the target operation time. Those skilled in the art can easily determine the permissible range that can be considered the maximum (or minimum) value of the function f(x) through preliminary experiments or magnetic analysis. Furthermore, in addition to depending on the characteristics of the board end detection device 10 as described above regarding the setting of α, this permissible range is preferably determined for each board end detection device 10 based on the prediction accuracy of the target board end position, computation time, etc. This permissible range can also be modified periodically as needed. Typically, this permissible range is approximately a few percent or less of the difference between the maximum and minimum values ​​of the function f(x) (Lmax - Lmin), for example, it can be less than 5%, 3%, 2%, 1%, or 0.5% of that difference.

[0096] The second position x2 is located inside the device width direction from the position x0 at the end of the plate, and is for a test steel plate tilted relative to the plurality of detection coils 28 in the preliminary test (e.g., Figure 9The value of the Sigmoid function f(x) obtained from the test steel plates 36A and 36B is compared with that for test steel plates that remain horizontally floating relative to multiple detection coils 28 (e.g., Figure 9 The error in the value of the Sigmoid function f(x) obtained from the test steel plates (shown by curves A2~A4 and B2~B4) becomes the position of the maximum value of a predetermined tolerance range. The tolerance range can also be determined experimentally. For example, the tolerance range can be predetermined through preliminary tests based on the required prediction accuracy of the plate end position, computation time, etc. Those skilled in the art can easily determine the tolerance range through preliminary tests or magnetic analysis. This tolerance range depends not only on the characteristics of the device but is preferably determined for each device based on the prediction accuracy of the target plate end position, etc. The tolerance range can also be modified periodically as needed. Typically, the tolerance range is approximately a few percent or less of the difference between the maximum and minimum values ​​of the function f(x) (Lmax-Lmin), for example, less than 5%, less than 3%, less than 2%, less than 1%, or less than 0.5% of this difference.

[0097] Alternatively, information related to the length of the interval can be pre-stored in volatile memory 44 or non-volatile memory 46, and the arithmetic processing unit 66 retrieves the information related to the length of the interval pre-stored in volatile memory 44 or non-volatile memory 46. Additionally, the information related to the length of the interval may be, for example, the position of the end of the steel plate 14 (e.g., Figure 9 The interval (length) between the position where the horizontal axis value is 0 and the first position x1, and the interval (length) between the position of the end of the steel plate 14 and the second position x2. If information related to the length of this interval is stored in advance, the specific position of the first specific interval in the width direction of the device can be determined based on the approximate position of the end of the steel plate 14 predicted by the first approximation (including the aforementioned non-approximation method) and the pre-stored information related to the length of the interval. Then, based on the relationship between the position x of each detection unit and the change amount f of the signal of each grinding unit within the determined first specific interval, the position of the end of the steel plate 14 can be accurately detected.

[0098] As explained above, in the second embodiment, during the preliminary test using a test steel plate as a substitute for the steel plate, the first position x1 and the second position x2 defined above are determined. When a range having a length equivalent to the distance from the first position x1 to the second position x2 is defined as the first specific range, the arithmetic processing unit 66 can also predict the position of the end of the steel plate 14 and set the first specific range within the range including the position of the end of the steel plate 14. Furthermore, the arithmetic processing unit 66 can also detect the position of the end of the steel plate 14 based on the relationship between the change in signal f detected by each detection coil 28 in the first specific range and the position x of each detection coil 28 in the first specific range in the device width direction.

[0099] According to the second embodiment, the region affected by the tilt of the steel plate 14 is removed from the overall region of the plurality of sensors 18 (e.g., Figure 9 The interval obtained after the interval exceeding 40mm shown (e.g., Figure 9 The data corresponding to the range of -70mm to 40mm shown is used to detect the position of the end of the steel plate 14, thus mitigating the effect of the tilt of the steel plate 14 and detecting the position of the end of the steel plate 14.

[0100] Furthermore, in the second embodiment, as described above, in order to predict the position of the end of the steel plate 14, the arithmetic processing unit 66 can also perform a first approximation based on the Sigmoid function, and use the Sigmoid function to perform a second approximation on the relationship between the change in signal corresponding to the intensity of the magnetic field corresponding to the interval set based on the Sigmoid function obtained through the first approximation and the position of the sensor 18. The data used for the second approximation can also be the data corresponding to the interval from the data used for the first approximation. Furthermore, the arithmetic processing unit 66 can also derive the position of the horizontal axis, which divides the range of values ​​considered as the upper limit and the range considered as the lower limit in the vertical axis values ​​of the Sigmoid function obtained by the second approximation into the aforementioned predetermined specific proportions, thereby detecting the position of the end of the steel plate 14. In this way, relative to the case of a horizontal steel plate 14, the second approximation is performed without using data on the range of the change in signal corresponding to the intensity of the magnetic field, thereby obtaining a new Sigmoid function, thus further mitigating the influence caused by the tilt of the steel plate 14, and detecting the position of the end of the steel plate 14. That is, by performing the second approximation, the detection accuracy when detecting the position of the end of the steel plate 14 can be improved compared to the case of performing the first approximation.

[0101] Furthermore, the arithmetic processing unit 66 can, after performing two approximations, derive the position of the horizontal axis, which divides the range of values ​​considered as the upper and lower limits of the vertical axis of the Sigmoid function obtained from the first approximation, into the aforementioned predetermined specific proportions, thereby detecting the approximate position of the plate end. Moreover, during the first approximation, it is also possible to extract multiple points where the vertical axis values ​​are considered as the upper limits (e.g., in...). Figure 9 In the middle, the point that is closest to the approximate end position of the plate (among the points corresponding to -70~-40mm). Figure 9 In the middle, the point corresponding to -40mm), the position of sensor 18 corresponding to the extracted point is used as the starting point of the interval used for the second approximation. In this way, a range that does not affect the approximation is not used, instead of a range considered as an upper limit of continuous values ​​(e.g., in...). Figure 9 The second approximation is performed using data from points corresponding to -70 to -30 mm, thus reducing the burden on processor 42 during the second approximation.

[0102] In addition, Figure 9 In the chart shown, since inductance is used as the detected signal, the relationship between the vertical and horizontal axes is represented as the value of the vertical axis decreases as the value of the horizontal axis increases. However, based on the calculation method of the vertical axis value (including changing the detected object to voltage or current), we can also assume that the value of the vertical axis increases as the value of the horizontal axis increases (in other words, Figure 9 (The graph is shown upside down). In this case, the processing unit 66 can also set the position of the outermost sensor 18 in the width direction of the device as the point where the vertical axis value is considered the lower limit, and set the position of the sensor 18 corresponding to the point where the vertical axis value is the largest among the points where the vertical axis value is not affected even if the steel plate 14 is tilted and the vertical axis value is considered the upper limit value. Furthermore, the processing unit 66 can also detect the position of the end of the steel plate 14 based on the amount of change in the signal corresponding to the strength of the magnetic field obtained from the sensors 18 that exist in the interval from the start point to the end point.

[0103] Furthermore, in the case where the value of the Sigmoid function f(x) obtained for the test steel plate increases as the position x of the detection coil 28 changes outward in the width direction of the device ( Figure 9 In the case shown in the upper left diagram), the first position x1 can also be set to the position corresponding to the maximum value of the Sigmoid function f(x). However, this is problematic when the value of the Sigmoid function f(x) obtained from the test steel plate decreases as the position x of the detection coil 28 changes outward in the width direction of the device. Figure 9In the case where the chart is displayed upside down, the first position x1 can also be set to the position corresponding to the minimum value of the Sigmoid function f(x).

[0104] [Third Implementation Method] Next, the third embodiment of this disclosure will be described. Content that is repeated in the first embodiment will be omitted from the description using the same terminology.

[0105] In the second embodiment described above, when the relationship between the change in signal detected by all sensors 18 and the position of the sensors 18 is approximated using the Sigmoid function, the interval affected by the tilt of the steel plate 14 is removed from the overall interval of the multiple sensors 18 (e.g., Figure 9 The interval after the interval exceeding 40mm shown (e.g., Figure 9 Using the data corresponding to the set range (-70mm to 40mm), the position of the end of the steel plate 14 is detected.

[0106] In contrast, the inventors conducted the following experiment: A range narrower than the overall range of the multiple sensors 18 was pre-defined (e.g., equivalent to...). Figure 9 The range shown is from -40mm to 40mm, which is equivalent to 80mm, while the position is from the outside of the device width direction (e.g., Figure 9 The starting point of the interval is shifted inward sequentially from the -70mm position shown. While using the Sigmoid function to approximate the relationship between the change in the signal corresponding to the strength of the magnetic field obtained for each interval and the position of the sensor 18, the position of the horizontal axis, which is divided into the range of values ​​considered as the upper limit and the lower limit of the vertical axis of the approximate Sigmoid function, is determined as the plate end.

[0107] Figure 10This example illustrates the relationship between the experimentally detected position of the board end and the number of times the starting point is shifted sequentially at each position of sensor 18. The vertical axis represents the relative position of the detected board end when the actual position of the board end is set to 0, and the horizontal axis represents the number of times the starting point is shifted sequentially at each position of sensor 18. Here, the inventors have observed that when the number of times the starting point is shifted sequentially at each position of sensor 18 is 1 to 3 times, and 9 times or more, the detected position of the board end changes when the starting point is shifted. However, when the number of times the starting point is shifted sequentially at each position of sensor 18 is 4 to 8 times, the detected position of the board end remains stable near 0 even when the starting point is shifted. This is because when the number of times the starting point is shifted sequentially at each position of sensor 18 is 4 to 8, the actual board end is located near the horizontal axis, which divides the range of values ​​considered as the upper and lower limits of the approximate Sigmoid function's vertical axis by the aforementioned predetermined specific proportion.

[0108] Furthermore, based on the above insights, the inventors, from the outer position in the width direction of the device (e.g., Figure 9 From the -70mm position shown, a predetermined number of sensors 18 are selected sequentially from the sensor 18 that serves as the starting point among a plurality of sensors 18 (e.g., with...). Figure 9 The sensor 18 shown is in the range of -40mm to 40mm, which is equivalent to 80mm. While shifting the starting point, the position of the end of the steel plate 14 is detected based on the signal detected by the selected sensor 18. In this case, a predetermined number of sensors 18 are determined from the sensors 18 that are in the range of the detected end of the steel plate 14 even when the starting point is shifted. The correct position of the end of the steel plate 14 can be derived from the position of the end of the steel plate 14 detected based on the signal detected by the determined sensor 18.

[0109] Specifically, the inventors believe that if the position of the detected end of the steel plate 14 converges to a predetermined error range X for a predetermined number of times (e.g., N=5) or more, even if the starting point is shifted, a representative value (e.g., average value or median value) of the position of the detected end of the steel plate 14 in each of the N times can be calculated, and the calculated representative value can be used as the correct position of the end of the steel plate 14.

[0110] Furthermore, the number of sensors 18 selected from the sensors 18 that serve as the starting point described above, which is a predetermined number, can be set, for example, to the following number: the number of sensors 18 that are selected from the predetermined number of sensors 18 that serve as the starting point described above, and the number of sensors 18 that are selected from the predetermined number of sensors 18 .... (Refer to the following) Figure 9 The vertical axis value becomes multiple points that are considered as the upper limit value (e.g., in...). Figure 9 In the middle, the point corresponding to -70~-40mm) is the point closest to the position corresponding to the end of the plate (e.g., in Figure 9 In the middle, the point corresponding to -40mm) to the point corresponding to the value considered as the lower limit (e.g., in Figure 9 The number of points corresponding to the range up to 40mm. In addition, the values ​​of X and N can be set based on the results obtained by experimentally or analytically solving the amplitude distribution of signals detected by multiple sensors 18, assuming the height L1 from the reference height of sensor 18 to the reference height of the through plate line, the floating amount of steel plate 14, and the tilt of steel plate 14.

[0111] Based on the above considerations, in the third embodiment, the arithmetic processing unit 66 operates as follows: The arithmetic processing unit 66 sequentially selects a predetermined number of sensors 18 from a plurality of sensors 18, starting from the sensor 18 that serves as the starting point, from the outer position in the width direction of the device towards the inner side to set an interval (e.g., Figure 9 The interval shown is from -40mm to 40mm. While maintaining the interval (length) of this interval (for example, while maintaining the distance from the first position x1 to the second position x2 described later), the starting point of the set interval is shifted one by one according to each position of the sensor 18, and the position of the end of the steel plate 14 is detected based on the signal detected by the selected sensor 18 corresponding to the interval. In addition, the arithmetic processing unit 66 determines a predetermined number of sensors 18 from the plurality of sensors 18 that are considered to be within a constant range of the detected end position of the steel plate 14 even when the starting point is shifted. Then, the arithmetic processing unit 66 derives the correct end position of the steel plate 14 based on the position of the end of the steel plate 14 detected based on the signal detected by the determined sensor 18. Specifically, if the state in which the detected position of the steel plate 14 converges to a predetermined error range X continues for a predetermined number of times (e.g., N=5) or more even if the starting point is shifted, the arithmetic processing unit 66 calculates a representative value (e.g., average value or median value) of the position of the steel plate 14 detected in each of the N times, and uses the calculated representative value as the correct position of the steel plate 14.

[0112] Regarding the length of the interval, for example, in a preliminary test using a test steel plate as a substitute for the steel plate, the first position x1' and the second position x2, as defined below, can be determined and set to a length equivalent to the distance from the first position x1 to the second position x2.

[0113] The first position x1' is a position located on the outer side of the device width direction, relative to the position x0 at the end of the plate. In the preliminary test, when the value of the function f(x) obtained for the test steel plate increases as the position x of the detection coil 28 changes outward in the device width direction, this position is the innermost position in the device width direction within the interval where the function f(x) is obtained at its maximum value for the test steel plate. Conversely, when the value decreases as the position x of the detection coil 28 changes outward in the device width direction, this position is the innermost position in the device width direction within the interval where the function f(x) is obtained at its minimum value for the test steel plate. The interval where the maximum value of the function f(x) is obtained can also be the interval where the value considered as the upper limit mentioned above is obtained (e.g., in...). Figure 9 The range is from -70 to -40 mm.

[0114] Furthermore, although it also depends on the function used, there are many cases where "the position corresponding to the maximum (or minimum) value of the function f(x) for the test steel plate" is infinitely far outside the width direction of the device. In this case, the "interval in which the minimum (or minimum) value of the function f(x) is obtained for the test steel plate" exists at an infinitely far outside the width direction of the device. However, when determining the first position x1', the "minimum (or minimum) value of the function f(x)" is set as the value considered as the "minimum (or minimum) value of the function f(x)". Regardless of how much the original "minimum (or minimum) value of the function f(x)" changes, the allowable range of the "minimum (or minimum) value of the function f(x)" can be predetermined through preliminary tests, magnetic analysis, etc., based on the required prediction accuracy of the plate end position and the target computation time. In other words, those skilled in the art can easily determine the allowable range that can be considered as the maximum (or minimum) value of the function f(x) through preliminary tests or magnetic analysis. Furthermore, this allowable range depends not only on the characteristics of the board end detection device 10, but is preferably determined for each board end detection device 10 based on factors such as the prediction accuracy of the target board end position. This allowable range can also be modified periodically as needed. Typically, this allowable range is approximately a few percent or less of the difference between the maximum and minimum values ​​of the function f(x) (Lmax-Lmin), for example, it can be less than 5%, 3%, 2%, 1%, 0.5%, or 0.3% of that difference.

[0115] The second position x2 is located inside the device width direction from the position x0 at the end of the plate, and is for a test steel plate tilted relative to the plurality of detection coils 28 in the preliminary test (e.g., Figure 9 The value of the Sigmoid function f(x) obtained from the test steel plates 36A and 36B is compared with that for test steel plates that remain horizontally floating relative to multiple detection coils 28 (e.g., Figure 9 The error in the value of the Sigmoid function f(x) obtained from the test steel plates (shown by curves A2~A4 and B2~B4) becomes the position of the maximum value of a predetermined tolerance range. The tolerance range can also be determined experimentally. For example, the required tolerance range can be predetermined through preliminary experiments, based on the desired prediction accuracy of the plate end position and the target computation time, etc. Furthermore, the second position x2 in the third embodiment of this application is the same as the second position x2 in the second embodiment described above. Therefore, the explanation of the method for determining the second position x2 and its range, etc., in this paragraph is omitted (for details, refer to the second embodiment).

[0116] Alternatively, information related to the length of the interval can be pre-stored in volatile memory 44 or non-volatile memory 46, and the arithmetic processing unit 66 retrieves the information related to the length of the interval pre-stored in volatile memory 44 or non-volatile memory 46. Additionally, the information related to the length of the interval may be, for example, the position of the end of the steel plate 14 (e.g., Figure 9 The length is the interval (length) between the position where the horizontal axis value is 0 and the first position x1', and the interval (length) between the position of the plate end of the steel plate 14 and the second position x2. Alternatively, the length can be the sum of these two intervals (lengths). If information related to the length of this interval is stored in advance, it is possible to offset the start point (and end point) of the second specific interval at each position of each detection unit along the width direction of the device while maintaining the interval (length) of the second specific interval; in other words, it is possible to move the second specific interval along the width direction of the device.

[0117] Furthermore, the moving object interval that moves the second specific interval along the width direction of the device does not need to be the entire width of the device. For example, it can be set near the approximate position of the end of the steel plate 14 predicted by the first approximation of the second embodiment described above (including the non-approximation method described above).

[0118] Furthermore, in the preliminary test using a test steel plate as a substitute for the steel plate, the first position x1' and the second position x2 defined above are determined. When a range having a length equivalent to the distance from the first position x1' to the second position x2 is defined as the second specific range, the calculation processing unit 66 can also detect the position of the end of the steel plate 14 by performing the following calculation processing. That is, the calculation processing unit 66 can also repeatedly perform processing based on the relationship between the change in signal f detected by each detection coil 28 of the second specific range and the position x of each detection coil of the second specific range in the device width direction, while shifting the starting point of the second specific range in the device width direction according to each position of the detection coil 28, to derive the position of the end of the steel plate 14. From the range after the second specific range is moved, the minimum range (e.g., the minimum range where the change in the position of the end of the steel plate 14 caused by the movement of the second specific range is minimal) is determined. Figure 10 The position of the end of the steel plate 14 obtained within the minimum range (4 to 8 offsets) will be detected as the position of the end of the steel plate 14. Alternatively, the calculation processing unit 66 can also detect the representative value (e.g., average value, median value, maximum value, or minimum value) of the position of the end of the steel plate 14 obtained within the minimum range as the position of the end of the steel plate 14.

[0119] According to the third embodiment, a predetermined number of sensors 18 are determined from among the plurality of sensors 18 whose starting point is considered to be within a constant range of the detected end position of the steel plate 14 even when the starting point is shifted. The correct end position of the steel plate 14 is derived based on the position of the end position of the steel plate 14 detected by the determined sensors 18. Therefore, the detection accuracy of the end position of the steel plate 14 can be improved.

[0120] Additionally, not using a range of values ​​considered as upper limits that are continuous does not affect the approximation (e.g., in...). Figure 9 The approximation is performed using data from points corresponding to -70 to -30 mm, thus reducing the burden on the processor 42 during the approximation process.

[0121] Additionally, the area affected by the tilt of the steel plate 14 was removed from the overall area of ​​the multiple sensors 18 (e.g., Figure 9 The interval obtained after the interval exceeding 40mm shown (e.g., Figure 9 The data corresponding to the range of -40mm to 40mm shown is used to detect the position of the end of the steel plate 14, thus mitigating the effect of the tilt of the steel plate 14 and detecting the position of the end of the steel plate 14.

[0122] Furthermore, the value of the Sigmoid function f(x) obtained for the test steel plate increases as the position x of the detection coil 28 changes outward in the width direction of the device. Figure 9 In the case shown in the upper left diagram), the first position x1' can also be set as the innermost position in the device width direction within the interval where the maximum value of the function f(x) obtained for the test steel plate is obtained. However, the value of the Sigmoid function f(x) obtained for the test steel plate decreases as the position x of the detection coil 28 changes outward in the device width direction. Figure 9 In the case where the graph is displayed upside down, the first position x1' can also be set as the innermost position in the width direction of the device within the interval where the minimum value of the function f(x) is obtained for the test steel plate in the preliminary test. Alternatively, the interval where the minimum value of the function f(x) is obtained can also be the interval corresponding to the interval where the value considered as the upper limit is obtained (e.g., in...). Figure 9 For example, the range is -70 to -40 mm.

[0123] Furthermore, in the above embodiments, as an example of the plate end detection device 10, a case in which multiple sensors 18 are used is described, but the plate end detection device 10 can also be constituted by a single sensor 18. It is also possible to detect the position of the end of the steel plate 14 based on the change in signal corresponding to the strength of the magnetic field at the position of the sensor 18 while moving a single sensor 18, which has a magnetic yoke 24, an excitation coil 26, and a detection coil 28, in the width direction of the device.

[0124] Alternatively, a magnetic yoke extending along the width of the device, an excitation coil corresponding to the magnetic yoke, and multiple detection coils arranged along the width of the device can be used to detect the position of the end of the steel plate 14 based on the change in signal corresponding to the strength of the magnetic field at the position of the multiple detection coils 28. Details will be described in the fourth embodiment.

[0125] Here, an example is given of the excitation coil 26 and the detection coil 28 used for the sensor being mounted on the yoke as different coils, but the excitation coil 26 and the detection coil 28 can also be composed of the same coil, detecting the result of the magnetic field generated by itself being affected by the steel plate.

[0126] Furthermore, while the above example demonstrates the use of a magnetic yoke as a strongly magnetic core material, it is not necessary to use a magnetic yoke. Additionally, the magnetic field generating unit only needs to be able to generate a magnetic field and can be an excitation coil without a strongly magnetic core material. Similarly, the detection unit only needs to be able to detect a signal corresponding to the strength of the magnetic field and can be a detection coil without a strongly magnetic core material.

[0127] [Fourth Implementation Method] Next, the fourth embodiment of this disclosure will be described.

[0128] Figure 11 Figure 12 shows an example of the sensor 118 according to the fourth embodiment. In the fourth embodiment, instead of multiple sensors 18 in the first embodiment, a single sensor 118 is used. The sensor 118 has a magnetic yoke 124, an excitation coil 126, and multiple detection coils 128. The magnetic yoke 124 is made of a magnetic material such as a ferrite core, and has a pair of core portions 132 and a connecting portion 134. The pair of core portions 132 extend in the vertical direction, and the connecting portion 134 connects the lower ends of the pair of core portions 132 to each other. The magnetic yoke 124 is provided to extend in the transport direction.

[0129] An excitation coil 126 is wound around one of a pair of cores 132 via a winding tube (not shown). The excitation coil 126 is arranged to extend in the transport direction by being wound around one core 132. A plurality of detection coils 128 are arranged in the width direction of the device. Each detection coil 128 is positioned above the other core 132 of the pair of cores 132. The sensor 118 has an excitation coil 126 relative to the plurality of detection coils 128, and the excitation coil 126 is shared with respect to the plurality of detection coils 128.

[0130] The above describes one embodiment of the present disclosure, but the present disclosure is not limited to the above. In addition to the above, various modifications can be made without departing from its spirit.

[0131] The entire disclosure of Japanese Patent Application No. 2024-035343, filed on March 7, 2024, is incorporated herein by reference.

[0132] The following are notes relating to this disclosure.

[0133] (Note 1) A plate end detection device detects the position of the end of a steel plate within a cooling device for cooling the steel plate. The plate end detection device has the following features: A magnetic field generating unit generates a magnetic field and is disposed in the space created between two adjacent conveying rollers of a plurality of conveying rollers that convey the steel plate and the path through which the steel plate passes. Multiple detection units are arranged in the width direction of the plate end detection device corresponding to the width direction of the steel plate, and at their respective positions detect a signal corresponding to the strength of the magnetic field obtained by reflecting the influence of the steel plate in the magnetic field generated by the magnetic field generating unit; and The processing unit detects the position of the end of the steel plate based on the relationship between the change in the signal detected by the detection unit and the position of the detection unit. The processing unit uses a function to approximate the relationship between the change in the signal and the position of the detection unit, as shown in a graph having a first axis corresponding to the change in the signal and a second axis corresponding to the position of the detection unit. The position of the second axis, which divides the range of values ​​considered as the upper limit and the range of values ​​considered as the lower limit of the first axis of the function obtained by the approximation into a predetermined specific ratio, is the position of the end of the steel plate.

[0134] (Note 2) The plate end detection device as described in Appendix 1 The specific ratio is determined as follows: Using a test piece that replaces the steel plate, the relationship between the change in the signal and the position of the detection unit was obtained. The function is used to approximate the relationship between the change in the signal and the position of the detection unit, as shown in the graph obtained using the test piece. The division ratio is determined by dividing the range of values ​​considered as the upper limit and the range of values ​​considered as the lower limit of the first axis of the function obtained by the approximation into the position of the second axis corresponding to the position of the end of the test piece. Calculate the average of the multiple segmentation ratios obtained by changing the position of the end of the test piece relative to the position of the detection part in the width direction of the device.

[0135] (Note 3) The plate end detection device as described in Appendix 1 or Appendix 2 The computing and processing unit When using the function to approximate the relationship between the change in the signal shown in the graph and the position of the detection unit... Starting from the outer edge of the plate end along the width direction of the device along the steel plate, the positions of the detection units corresponding to the points where the value of the first axis is considered to be the upper limit are sequentially set as the starting points. The positions of the detection units corresponding to the points where the value of the first axis decreases from the upper limit towards the lower limit, and where the value of the first axis is unaffected even if the steel plate is tilted and is considered to be the lower limit, are set as the ending points. The starting point is defined as the position of the detection unit corresponding to the point where the value of the first axis is considered to be the lower limit, and the ending point is defined as the position of the detection unit corresponding to the point where the value of the first axis increases from the value considered to be the lower limit towards the upper limit, and the value of the first axis is not affected even if the steel plate is tilted, and the value of the first axis is considered to be the upper limit. The position of the end of the steel plate is detected based on the change in the signal obtained from the detection unit that exists in the interval from the starting point to the ending point among the plurality of detection units.

[0136] (Note 4) The plate end detection device as described in Appendix 1 or Appendix 2 The processing unit, along the width direction of the steel plate, sequentially selects a predetermined number of detection units from among the plurality of detection units, starting from the outer side of the plate end, thus shifting the starting point. And when the position of the end of the steel plate is detected based on the signal detected by the selected detection unit, a predetermined number of detection units are determined from the plurality of detection units that are considered to be within a constant range of the detected end of the steel plate even if the starting point is shifted. Based on the position of the end of the steel plate detected based on the signal detected by the determined detection unit, the correct position of the end of the steel plate is derived.

[0137] (Note 5) A plate end detection device detects the position of the end of a steel plate within a cooling device for cooling the steel plate. The plate end detection device comprises: A magnetic field generating unit generates a magnetic field and is disposed in the space created between two adjacent conveying rollers of a plurality of conveying rollers that convey the steel plate and the path through which the steel plate passes. Multiple detection units are arranged in the width direction of the plate end detection device corresponding to the width direction of the steel plate, and detect a signal corresponding to the strength of the magnetic field obtained by reflecting the influence of the steel plate in the magnetic field generated by the magnetic field generating unit; and The processing unit detects the position of the end of the steel plate based on the change f of the signal detected by each of the detection units and the position x of each of the detection units in the width direction. The processing unit obtains the relationship between the change in signal f detected by each of the detection units and the position x of each of the detection units in the width direction, approximates the relationship using the function f(x), and detects the position x0 calculated according to the following formula (1) as the position of the end of the steel plate. f(x0)=Lmin+α×(Lmax-Lmin)…(1) Here, Lmax is the maximum value of the function f(x), Lmin is the minimum value of the function f(x), and α is a predetermined coefficient.

[0138] (Note 6) The plate end detection device as described in Appendix 5 It has a storage unit for storing the coefficients. The coefficient is a coefficient set using a test steel plate as a substitute for the steel plate and based on a specific coefficient setting process. The coefficient setting process Using the test steel plate, the relationship between the change f of the signal detected by each of the detection units and the position x of each of the detection units in the width direction is obtained. The relationship is approximated using the function f(x). The actual position x0' of the end of the test steel plate is input into the function f(x) to calculate the value of the function f(x). Find the ratio by which the range of the maximum and minimum values ​​of the function f(x) is divided using the value of the function f(x0'), i.e., the division ratio. Multiple segmentation ratios are obtained by changing the position of the end of the test steel plate relative to the positions of the multiple detection parts in the width direction. The coefficients are set based on multiple of the aforementioned segmentation ratios.

[0139] (Note 7) The plate end detection device as described in Appendix 5 or Appendix 6 In a preliminary test using a test steel plate as a substitute for the aforementioned steel plate, a first position x1 and a second position x2 were determined as follows: a first specific interval was defined as an interval having a length equivalent to the distance from the first position x1 to the second position x2. The processing unit predicts the position of the end of the steel plate, sets a first specific interval within a range including the position of the end of the steel plate, and detects the position of the end of the steel plate based on the relationship between the change f of the signal detected by each detection unit in the first specific interval and the position x of each detection unit in the first specific interval in the width direction.

[0140] Here, the first position x1 is a position further outward in the width direction than the position x0. Furthermore, in the preliminary test, if the value of the function f(x) obtained for the test steel plate increases as the position x of the detection unit changes outward in the width direction, then the first position x1 corresponds to the maximum value of the function f(x). If the value decreases as the position x of the detection unit changes outward in the width direction, then the first position x1 corresponds to the minimum value of the function f(x). The second position x2 is a position that is inside the width direction compared to the position x0, and in the preliminary test, the second position x2 is the position where the error between the value of the function f(x) obtained for the test steel plate tilted relative to the plurality of detection units and the value of the function f(x) obtained for the test steel plate floating in a horizontal state relative to the plurality of detection units is the maximum value of a predetermined tolerance range.

[0141] (Postscript 8) The plate end detection device as described in Appendix 5 or Appendix 6 In a preliminary test using a test steel plate as a substitute for the aforementioned steel plate, a first position x1' and a second position x2 were determined as follows: a second specific interval was defined as an interval having a length equivalent to the distance from the first position x1' to the second position x2. The processing unit moves the second specific interval in the width direction by shifting the starting point of the second specific interval according to each position of the detection unit in the width direction, and repeatedly performs processing to derive the position of the end of the steel plate based on the relationship between the change amount f of the signal detected by each detection unit of the second specific interval and the position x of each detection unit of the second specific interval in the width direction. The arithmetic processing unit determines from the range after the second specific interval has been moved the minimum range in which the change in the position of the end of the steel plate caused by the movement of the second specific interval is minimal, and detects the position of the end of the steel plate obtained within the minimum range as the position of the end of the steel plate.

[0142] Here, the first position x1' is a position further outward in the width direction than the position x0. Furthermore, in the preliminary test, if the value of the function f(x) obtained for the test steel plate increases as the position x of the detection unit changes outward in the width direction, then the first position x1' is the innermost position in the width direction within the interval where the function f(x) has its maximum value for the test steel plate. If the value decreases as the position x of the detection unit changes outward in the width direction, then the first position x1' is the innermost position in the width direction within the interval where the function f(x) has its minimum value for the test steel plate. The second position x2 is a position that is inside the width direction compared to the position x0, and in the preliminary test, the second position x2 is the position where the error between the value of the function f(x) obtained for the test steel plate tilted relative to the plurality of detection units and the value of the function f(x) obtained for the test steel plate floating in a horizontal state relative to the plurality of detection units is the maximum value of a predetermined tolerance range.

[0143] (Note 9) A plate end detection method detects the position of the end of a steel plate within a cooling device for cooling a steel plate. The method uses a plate end detection device comprising: one or more magnetic field generating units that generate a magnetic field and are disposed in the space created between two adjacent conveying rollers of a plurality of conveying rollers conveying the steel plate and the path through which the steel plate passes; a plurality of detection units arranged in a width direction of the steel plate, each detecting at its respective position a signal corresponding to the strength of the magnetic field obtained by reflecting the influence of the steel plate in the magnetic field generated by the magnetic field generating units; and a processing unit that detects the position of the end of the steel plate based on the relationship between the change in the signal detected by the detection units and the position of the detection units. The plate end detection method has the following characteristics: The detection step involves using the plurality of detection units to detect, at each of the locations where the plurality of detection units are set, a signal corresponding to the strength of the magnetic field obtained by reflecting the influence of the steel plate in the magnetic field generated by the magnetic field generating unit; and In the calculation and processing step, the calculation and processing unit detects the position of the end of the steel plate based on the relationship between the change in the signal detected by the detection unit and the position of the detection unit. In the computational processing step, a function is used to approximate the relationship between the change in the signal and the position of the detection unit, as shown in a graph having a first axis corresponding to the change in the signal and a second axis corresponding to the position of the detection unit. The position of the second axis, which divides the range of values ​​considered as the upper limit and the range of values ​​considered as the lower limit of the first axis of the function obtained by the approximation into a predetermined specific ratio, is the position of the end of the steel plate.

[0144] (Postscript 10) A method for detecting the end position of a steel plate involves detecting the position of the end of the steel plate within a cooling device for cooling the steel plate. The method utilizes an end plate detection device. The plate end detection device includes: one or more magnetic field generating units that generate a magnetic field and are disposed in the space created between two adjacent conveying rollers of a plurality of conveying rollers conveying the steel plate and the path through which the steel plate passes; a plurality of detection units arranged in the width direction of the plate end detection device corresponding to the width direction of the steel plate, which detect signals corresponding to the strength of the magnetic field obtained by reflecting the influence of the steel plate in the magnetic field generated by the magnetic field generating units; and a processing unit that detects the position of the plate end of the steel plate based on the change f of the signal detected by each of the detection units and the position x of each of the detection units in the width direction. The plate end detection method has the following characteristics: The detection step involves using multiple detection units to detect a signal corresponding to the strength of the magnetic field obtained by reflecting the influence of the steel plate in the magnetic field generated by the magnetic field generating unit; and In the calculation and processing step, the calculation and processing unit detects the position of the end of the steel plate based on the change in signal f detected by each of the detection units and the position x of each of the detection units in the width direction. In the aforementioned computational processing steps, The relationship between the change f of the signal detected by each of the detection units and the position x of each of the detection units in the width direction is obtained. The relationship is approximated using the function f(x). The position x0 calculated according to the following formula (1) is detected as the position of the end of the steel plate.

[0145] f(x0)=Lmin+α×(Lmax-Lmin)…(1) Here, Lmax is the maximum value of the function f(x), Lmin is the minimum value of the function f(x), and α is a predetermined coefficient.

[0146] (Postscript 11) The plate end detection method as described in Appendix 10 The plate end detection device has a storage section for storing the coefficients. The coefficient is a coefficient set using a test steel plate as a substitute for the steel plate and based on a specific coefficient setting process. The coefficient setting process Using the test steel plate, the relationship between the change f of the signal detected by each of the detection units and the position x of each of the detection units in the width direction is obtained. The relationship is approximated using the function f(x). The actual position x0' of the end of the test steel plate is input into the function f(x) to calculate the value of the function f(x). Find the ratio by which the range of the maximum and minimum values ​​of the function f(x) is divided using the value of the function f(x0'), i.e., the division ratio. Multiple segmentation ratios are obtained by changing the position of the end of the test steel plate relative to the positions of the multiple detection parts in the width direction. The coefficients are set based on multiple of the aforementioned segmentation ratios.

[0147] (Postscript 12) The plate end detection method as described in Appendix 10 or Appendix 11 In a preliminary test using a test steel plate as a substitute for the aforementioned steel plate, a first position x1 and a second position x2 were determined as follows: a first specific interval was defined as an interval having a length equivalent to the distance from the first position x1 to the second position x2. In the aforementioned computational processing steps, Predict the position of the end of the steel plate. The first specific interval is defined within the range of the position of the plate end containing the steel plate. The position of the end of the steel plate is detected based on the relationship between the change f of the signal detected by each of the detection units in the first specific interval and the position x of each of the detection units in the first specific interval in the width direction.

[0148] Here, the first position x1 is a position further outward in the width direction than the position x0. Furthermore, in the preliminary test, if the value of the function f(x) obtained for the test steel plate increases as the position x of the detection unit changes outward in the width direction, then the first position x1 corresponds to the maximum value of the function f(x). If the value decreases as the position x of the detection unit changes outward in the width direction, then the first position x1 corresponds to the minimum value of the function f(x). The second position x2 is a position that is inside the width direction compared to the position x0, and in the preliminary test, the second position x2 is the position where the error between the value of the function f(x) obtained for the test steel plate tilted relative to the plurality of detection units and the value of the function f(x) obtained for the test steel plate floating in a horizontal state relative to the plurality of detection units is the maximum value of a predetermined tolerance range.

[0149] (Postscript 13) The plate end detection method as described in Appendix 10 or Appendix 11 In a preliminary test using a test steel plate as a substitute for the aforementioned steel plate, a first position x1' and a second position x2 were determined as follows: a second specific interval was defined as an interval having a length equivalent to the distance from the first position x1' to the second position x2. In the aforementioned processing step, while shifting the second specific interval in the width direction by offsetting the starting point of the second specific interval according to each position of the detection unit, the processing of deriving the position of the end of the steel plate based on the relationship between the change f of the signal detected by each detection unit of the second specific interval and the position x of each detection unit of the second specific interval in the width direction is repeatedly performed. In the calculation process, a minimum range is determined from the range after the second specific interval is moved, which is the range with the least change in the position of the end of the steel plate caused by the movement of the second specific interval, and the position of the end of the steel plate obtained within the minimum range is detected as the position of the end of the steel plate.

[0150] Here, the first position x1' is a position further outward in the width direction than the position x0. Furthermore, in the preliminary test, if the value of the function f(x) obtained for the test steel plate increases as the position x of the detection unit changes outward in the width direction, then the first position x1' is the innermost position in the width direction within the interval where the function f(x) has its maximum value for the test steel plate. If the value decreases as the position x of the detection unit changes outward in the width direction, then the first position x1' is the innermost position in the width direction within the interval where the function f(x) has its minimum value for the test steel plate. The second position x2 is a position that is inside the width direction compared to the position x0, and in the preliminary test, the second position x2 is the position where the error between the value of the function f(x) obtained for the test steel plate tilted relative to the plurality of detection units and the value of the function f(x) obtained for the test steel plate floating in a horizontal state relative to the plurality of detection units is the maximum value of a predetermined tolerance range.

[0151] Explanation of reference numerals in the attached figures 10 Plate End Detection Device 12 Conveyor Rollers 14 Steel Plate 16 Cooling device 18 sensors 20 processing devices 24 Magnetic yoke 26 Excitation Coil 28 Detection coil 36 Test steel plates

Claims

1. A plate end detection device for detecting the position of the end of a steel plate within a cooling device for cooling a steel plate. The plate end detection device has the following features: One or more magnetic field generating units generate a magnetic field and are disposed in the space created between two adjacent conveying rollers of a plurality of conveying rollers that convey the steel plate and the path through which the steel plate passes; Multiple detection units are arranged in the width direction of the plate end detection device corresponding to the width direction of the steel plate, and detect the signal corresponding to the strength of the magnetic field obtained by reflecting the influence of the steel plate in the magnetic field generated by the magnetic field generating unit; as well as The processing unit detects the position of the end of the steel plate based on the change f of the signal detected by each of the detection units and the position x of each of the detection units in the width direction. The processing unit obtains the relationship between the change f of the signal detected by each of the detection units and the position x of each of the detection units in the width direction, approximates the relationship using the function f(x), and detects the position x0 calculated according to the following formula (1) as the position of the end of the steel plate. f(x0)=Lmin+α×(Lmax-Lmin)…(1) Here, Lmax is the maximum value of the function f(x), Lmin is the minimum value of the function f(x), and α is a predetermined coefficient.

2. The plate end detection device as described in claim 1, It has a storage unit for storing the coefficients. The coefficient is a coefficient set using a test steel plate as a substitute for the steel plate and based on a specific coefficient setting process. The coefficient setting process uses the test steel plate to obtain the relationship between the change f of the signal detected by each of the detection units and the position x of each of the detection units in the width direction. The relationship is approximated using the function f(x). The actual position x0' of the end of the test steel plate is input into the function f(x) to calculate the value of the function f(x0'). The coefficient α, calculated by substituting the values ​​of the function f(x0'), the maximum value Lmax, and the minimum value Lmin of the function f(x) into the following equation (1'), is set as the coefficient. α=(f(x0')-Lmin) / (Lmax-Lmin)…(1').

3. The plate end detection device as described in claim 1 or 2, In a preliminary test using a test steel plate as a substitute for the aforementioned steel plate, at a first position x1 and a second position x2 as defined below, and with a first specific interval defined as an interval having a length equivalent to the distance from the first position x1 to the second position x2, The processing unit predicts the position of the end of the steel plate, sets a first specific interval within a range including the position of the end of the steel plate, and detects the position of the end of the steel plate based on the relationship between the change f of the signal detected by each detection unit in the first specific interval and the position x of each detection unit in the first specific interval in the width direction. Here, the first position x1 is a position further outward in the width direction than the position x0. Furthermore, in the preliminary test, if the value of the function f(x) obtained for the test steel plate increases as the position x of the detection unit changes outward in the width direction, then the first position x1 corresponds to the maximum value of the function f(x). If the value of the function f(x) obtained for the test steel plate decreases as the position x of the detection unit changes outward in the width direction, then the first position x1 corresponds to the minimum value of the function f(x). The second position x2 is a position that is inside the width direction compared to the position x0, and in the preliminary test, the second position x2 is the position where the error between the value of the function f(x) obtained for the test steel plate tilted relative to the plurality of detection units and the value of the function f(x) obtained for the test steel plate floating in a horizontal state relative to the plurality of detection units is the maximum value of a predetermined tolerance range.

4. The plate end detection device as described in claim 1 or 2, In a preliminary test using a test steel plate as a substitute for the aforementioned steel plate, a first position x1' and a second position x2 were determined, and a second specific interval was defined as a range having a length equivalent to the distance from the first position x1' to the second position x2. The processing unit moves the second specific interval in the width direction by shifting the starting point of the second specific interval at each position of the detection unit, and repeatedly performs processing to derive the position of the end of the steel plate based on the relationship between the change f of the signal detected by each detection unit of the second specific interval and the position x of each detection unit of the second specific interval in the width direction. The processing unit determines, from the range after the second specific interval has been moved, the minimum range that minimizes the change in the position of the steel plate end caused by the movement of the second specific interval, and detects the position of the steel plate end obtained within the minimum range, which is taken as the position of the steel plate end. Here, the first position x1' is a position further outward in the width direction than the position x0. Furthermore, in the preliminary test, if the value of the function f(x) obtained for the test steel plate increases as the position x of the detection unit changes outward in the width direction, then the first position x1' is the innermost position in the width direction within the interval where the function f(x) has its maximum value. If the value of the function f(x) obtained for the test steel plate decreases as the position x of the detection unit changes outward in the width direction, then the first position x1' is the innermost position in the width direction within the interval where the function f(x) has its minimum value. The second position x2 is a position that is inside the width direction compared to the position x0, and in the preliminary test, the second position x2 is the position where the error between the value of the function f(x) obtained for the test steel plate tilted relative to the plurality of detection units and the value of the function f(x) obtained for the test steel plate floating in a horizontal state relative to the plurality of detection units is the maximum value of a predetermined tolerance range.

5. A method for detecting the end position of a steel plate, comprising detecting the position of the end position of the steel plate within a cooling device for cooling the steel plate. The plate end detection method uses a plate end detection device. The plate end detection device has the following features: One or more magnetic field generating units generate a magnetic field and are disposed in the space created between two adjacent conveying rollers of a plurality of conveying rollers that convey the steel plate and the path through which the steel plate passes; Multiple detection units are arranged in the width direction of the plate end detection device corresponding to the width direction of the steel plate, and detect the signal corresponding to the strength of the magnetic field obtained by reflecting the influence of the steel plate in the magnetic field generated by the magnetic field generating unit; as well as The processing unit detects the position of the end of the steel plate based on the change f of the signal detected by each of the detection units and the position x of each of the detection units in the width direction. The plate end detection method has the following characteristics: The detection step involves using multiple detection units to detect a signal corresponding to the strength of the magnetic field obtained by reflecting the influence of the steel plate in the magnetic field generated by the magnetic field generating unit. as well as In the calculation and processing step, the calculation and processing unit detects the position of the end of the steel plate based on the change in signal f detected by each of the detection units and the position x of each of the detection units in the width direction. In the above processing step, the relationship between the change f of the signal detected by each of the detection units and the position x of each of the detection units in the width direction is obtained. The relationship is approximated by the function f(x), and the position x0 calculated according to the following formula (1) is detected as the position of the end of the steel plate. f(x0)=Lmin+α×(Lmax-Lmin)…(1) Here, Lmax is the maximum value of the function f(x), Lmin is the minimum value of the function f(x), and α is a predetermined coefficient.

6. The plate end detection method as described in claim 5, The plate end detection device has a storage section for storing the coefficients. The coefficient is a coefficient set using a test steel plate as a substitute for the steel plate and based on a specific coefficient setting process. The coefficient setting process uses the test steel plate to obtain the relationship between the change f of the signal detected by each of the detection units and the position x of each of the detection units in the width direction. The relationship is approximated using the function f(x). The actual position x0' of the end of the test steel plate is input into the function f(x) to calculate the value of the function f(x0'). The coefficient α, calculated by substituting the values ​​of the function f(x0'), the maximum value Lmax, and the minimum value Lmin of the function f(x) into the following equation (1'), is set as the coefficient. α=(f(x0')-Lmin) / (Lmax-Lmin)…(1').

7. The plate end detection method as described in claim 5 or 6, In a preliminary test using a test steel plate as a substitute for the aforementioned steel plate, at a first position x1 and a second position x2 as defined below, and with a first specific interval defined as an interval having a length equivalent to the distance from the first position x1 to the second position x2, In the computational processing step, the position of the end of the steel plate is predicted. A first specific interval is set within a range including the position of the end of the steel plate. Based on the relationship between the change f of the signal detected by each detection unit in the first specific interval and the position x of each detection unit in the first specific interval in the width direction, the position of the end of the steel plate is detected. Here, the first position x1 is a position further outward in the width direction than the position x0. Furthermore, in the preliminary test, if the value of the function f(x) obtained for the test steel plate increases as the position x of the detection unit changes outward in the width direction, then the first position x1 corresponds to the maximum value of the function f(x). If the value of the function f(x) obtained for the test steel plate decreases as the position x of the detection unit changes outward in the width direction, then the first position x1 corresponds to the minimum value of the function f(x). The second position x2 is a position that is inside the width direction compared to the position x0, and in the preliminary test, the second position x2 is the position where the error between the value of the function f(x) obtained for the test steel plate tilted relative to the plurality of detection units and the value of the function f(x) obtained for the test steel plate floating in a horizontal state relative to the plurality of detection units is the maximum value of a predetermined tolerance range.

8. The plate end detection method as described in claim 5 or 6, In a preliminary test using a test steel plate as a substitute for the aforementioned steel plate, a first position x1' and a second position x2 were determined, and a second specific interval was defined as a range having a length equivalent to the distance from the first position x1' to the second position x2. In the aforementioned processing step, while shifting the second specific interval in the width direction by offsetting the starting point of the second specific interval at each position of the detection unit, the process of deriving the position of the end of the steel plate based on the relationship between the change f of the signal detected by each detection unit of the second specific interval and the position x of each detection unit of the second specific interval in the width direction is repeatedly performed. In the aforementioned processing step, a minimum range is determined from the range after the second specific interval has been moved, which minimizes the change in the position of the steel plate end caused by the movement of the second specific interval. The position of the steel plate end obtained within this minimum range is then detected and taken as the position of the steel plate end. Here, the first position x1' is a position further outward in the width direction than the position x0. Furthermore, in the preliminary test, if the value of the function f(x) obtained for the test steel plate increases as the position x of the detection unit changes outward in the width direction, then the first position x1' is the innermost position in the width direction within the interval where the function f(x) has its maximum value. If the value of the function f(x) obtained for the test steel plate decreases as the position x of the detection unit changes outward in the width direction, then the first position x1' is the innermost position in the width direction within the interval where the function f(x) has its minimum value. The second position x2 is a position that is inside the width direction compared to the position x0, and in the preliminary test, the second position x2 is the position where the error between the value of the function f(x) obtained for the test steel plate tilted relative to the plurality of detection units and the value of the function f(x) obtained for the test steel plate floating in a horizontal state relative to the plurality of detection units is the maximum value of a predetermined tolerance range.

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