Calibration method, correlation thickness measurement method, electronic equipment and medium

Abstract

The invention provides a calibration method, a correlation thickness measuring method, electronic equipment and a medium. The method is used for error calibration of the correlation thickness measurement system. The method comprises the following steps: respectively establishing nominal distance sequences of an upper step surface and a lower step surface of a step gauge block group; controlling the step gauge block group to translate; acquiring a translation distance of the step gauge block group, an actual measurement distance of an upper step surface acquired by an upper distance measuring sensor in a translation process and an actual measurement distance of a lower step surface acquired by a lower distance measuring sensor; based on a nominal distance, an actually measured distance and a translation amount of an upper step surface and a lower step surface of the step gauge block group, performing piecewise linear fitting on the actually measured distance by taking a principle that an error between the fitting distance and the actually measured distance is minimum so as to obtain a calibration parameter; the calibration parameters comprise a first correction parameter used for correcting the nominal distance of the upper step surface, a second correction parameter used for correcting the nominal distance of the lower step surface, an upper sensor position deviation and a lower sensor position deviation. According to the method, accurate calibration parameters can be obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of transmission thickness measurement, and more particularly to a calibration method, a transmission thickness measurement method, an electronic device and a medium. BACKGROUND

[0002] The transmission thickness measurement method is a commonly used non-contact thickness measurement method, and is widely used in the thickness measurement of plate-shaped objects such as steel plates. The principle of the method is to perform transmission measurement by two distance measuring sensors (referred to as an upper distance measuring sensor and a lower distance measuring sensor) installed in an upper-lower position: the upper distance measuring sensor measures the distance from the upper surface of the target object, and the lower distance measuring sensor measures the distance from the lower surface of the target object. By combining the fixed interval distance between the two sensors, the accurate thickness value of the target object can be obtained through calculation.

[0003] However, in actual working scenarios, the installation angle and installation position of the distance measuring sensor may deviate, which seriously affects the thickness measurement accuracy.

[0004] Therefore, the present application is proposed. SUMMARY

[0005] The present application is proposed in consideration of the above problems. According to one aspect of the present application, a calibration method is provided for error calibration of a transmission thickness measurement system; the transmission thickness measurement system includes an upper distance measuring sensor and a lower distance measuring sensor located at the same vertical position, and the upper distance measuring sensor is located above the lower distance measuring sensor; the method includes: Taking the abutting surface of any two adjacent gauge blocks in the stepped gauge block set as a stepped reference surface, a nominal distance sequence of the upper stepped surface and the lower stepped surface of the stepped gauge block set is established based on the nominal thickness of each gauge block in the stepped gauge block set, the stepped gauge block set is arranged in a stepped shape by a plurality of gauge blocks, and the nominal distance sequence includes the nominal distance of the upper stepped surface and the lower stepped surface of each gauge block in the plurality of gauge blocks; The stepped gauge block set is controlled to translate so that the gauge blocks in the stepped gauge block set pass between the upper distance measuring sensor and the lower distance measuring sensor in turn; The translation distance of the stepped gauge block set and the measured distance of the upper stepped surface of the stepped gauge block set collected by the upper distance measuring sensor and the measured distance of the lower stepped surface of the stepped gauge block set collected by the lower distance measuring sensor during the translation process are obtained; The measured distance is piecewise linearly fitted based on the nominal distance and the measured distance of the upper step surface and the lower step surface of the step gauge block and the translation amount of the step gauge block, and the calibration parameters are obtained, including a first correction parameter for correcting the nominal distance of the upper step surface, a second correction parameter for correcting the nominal distance of the lower step surface, an upper sensor position deviation and a lower sensor position deviation.

[0006] The nominal distance of the step reference surface is determined based on the distance between the upper distance sensor and the lower distance sensor; and for any step surface other than the step reference surface in the step gauge block, the nominal distance of the step surface is determined based on the distance between the upper distance sensor and the lower distance sensor and the thickness of the gauge block between the step surface and the step reference surface.

[0007] The number of gauges in the step gauge block is 4, wherein the step reference surface is the lapping surface between the second gauge and the third gauge in the order from bottom to top; the nominal distance sequence of the upper step surface and the lower step surface of the step gauge block is: .

[0008] In the formula, the nominal distance sequence of the upper step surface of the step gauge block is represented by S; the nominal distance sequence of the lower step surface of the step gauge block is represented by S; G D represents the theoretical distance between the upper distance sensor and the lower distance sensor; H 1, H 2, H 3, H 4 respectively represent the nominal values of the thickness of each gauge in the order from bottom to top.

[0009] The piecewise linear fitting of the measured distance based on the nominal distance and the measured distance of the upper step surface and the lower step surface of the step gauge block and the translation amount of the step gauge block includes: a piecewise linear function of the upper step surface of the step gauge block is established based on the translation amount of the step gauge block and the nominal distance of the upper step surface of the step gauge block; a piecewise linear function of the lower step surface of the step gauge block is established based on the translation amount of the step gauge block and the nominal distance of the lower step surface of the step gauge block; The piecewise linear functions of the upper step surface and the lower step surface of the step gauge block are fitted respectively based on the principle of minimizing the distance and the measured distance error, so as to obtain the calibration parameters.

[0010] For example, when fitting the piecewise linear function of the upper and lower stepped surfaces of the stepped block group, L2 constraint is used for fitting; Preferably, after the fitting is completed, the method further includes: Determine whether the L2 constraint term related to the first correction parameter is greater than the first preset threshold; Determine whether the L2 constraint term related to the second correction parameter is greater than the second preset threshold; Determine whether the L2 constraint term related to the slope coefficient is greater than a third preset threshold, wherein the slope coefficient is the coefficient of the translation amount; When each L2 constraint is less than or equal to the corresponding preset threshold, the first correction parameter, the second correction parameter, the upper sensor position deviation and the lower sensor position deviation obtained in the current fitting are determined as the calibration parameters. Preferably, the method further includes: When any L2 constraint term exceeds the corresponding preset threshold, a prompt message is output to remind the user to make manual adjustments; After receiving the adjustment completion instruction, the measured distance between the upper stepped surface and the lower stepped surface is reacquired, and piecewise linear fitting is performed based on the latest acquired measured distance. Preferably, the step of outputting a prompt message when any L2 constraint term is greater than the corresponding preset threshold includes: When the L2 constraint term related to the first correction parameter is greater than the first preset threshold, a first prompt message is output, which indicates that there is an angular deviation in the upper ranging sensor. When the L2 constraint term related to the second correction parameter is greater than the second preset threshold, a second prompt message is output, which indicates that the lower ranging sensor has an angular deviation. When the L2 constraint term related to the slope coefficient is greater than the third preset threshold, a third prompt message is output. The third prompt message is used to indicate that there is an angular deviation between the length direction and the translation direction of the stepped block group.

[0011] For example, after obtaining the calibration parameters, the method further includes: The measured distance is calibrated using the calibration parameters to obtain the calibrated distance between the upper and lower stepped surfaces. Based on the calibration distance between each upper stepped surface and the corresponding lower stepped surface, the calibrated thickness measurement value of each block in the stepped block group is calculated. The calibration deviation is calculated based on the calibrated thickness measurement and nominal thickness value of each gauge block in the stepped gauge block group. When the calibration deviation is less than the deviation threshold, the calibration parameter is determined to be qualified. Otherwise, the measured distance is re-segmented and linearly fitted.

[0012] Exemplarily, the second step compensation block is arranged on the step block group and has a first step compensation block; The bottom surface of the first step compensation block is in abutment with the top surface of the lowermost block in the step block group, and the top surface of the first step compensation block is flush with the top surface of the uppermost block in the step block group; The top surface of the second step compensation block is in abutment with the bottom surface of the uppermost block in the step block group, and the bottom surface of the second step compensation block is flush with the bottom surface of the lowermost block in the step block group.

[0013] The application further provides a method for radiometric thickness measurement, which is used for a radiometric thickness measurement system; the radiometric thickness measurement system comprises an upper distance sensor and a lower distance sensor located at the same vertical position, and the upper distance sensor is located above the lower distance sensor; the method comprises: Calibration is performed by using the above method to obtain calibration parameters; The thickness of a target object is determined based on at least the calibration parameters and the distances measured by the upper distance sensor and the lower distance sensor respectively; Preferably, the temperature of the blocks in the step block group during the calibration process is an ideal working temperature; the thickness of the target object is determined based on at least the calibration parameters and the distances measured by the upper distance sensor and the lower distance sensor respectively, which comprises: The thickness of the target object is determined based on the calibration parameters, the difference between the current temperature and the ideal working temperature, and the distances measured by the upper distance sensor and the lower distance sensor respectively.

[0014] According to another aspect of the application, an electronic device is provided, which comprises a processor and a memory, the memory storing a computer program, and the processor is configured to execute the computer program to implement the method as described above.

[0015] According to still another aspect of the application, a computer readable storage medium is provided, which stores a computer program / instruction, and the computer program / instruction is executed by a processor to implement the method as described above.

[0016] In the above technical solution, the nominal distance and the measured distance of the upper and lower step surfaces in the step block group are fitted, the calibration parameters can be determined more accurately according to the difference between the two, so as to correct the errors caused by the insufficient installation accuracy of the installation position and the installation angle of the distance sensor in the radiometric thickness measurement process, and improve the accuracy of the radiometric thickness measurement.

[0017] The above description is only a summary of the technical solutions of the present application. In order to make the technical solutions of the present application more apparent, the present application can be implemented according to the content of the description, and in order to make the above and other purposes, features and advantages of the present application more apparent and easy to understand, the specific embodiments of the present application are described below. BRIEF DESCRIPTION OF DRAWINGS

[0018] The above and other purposes, features and advantages of the present application will become more apparent from the following detailed description of the embodiments of the present application taken in conjunction with the accompanying drawings. The accompanying drawings provide further understanding of the embodiments of the present application and constitute a part of the specification, together with the embodiments of the present application, to explain the present application, and do not constitute a limitation of the present application. In the drawings, the same reference numerals generally refer to the same parts or steps.

[0019] Figure 1 A schematic flowchart of a calibration method according to an embodiment of the present application is shown; Figure 2 A schematic diagram of a step gauge according to an embodiment of the present application is shown; Figure 3 A schematic diagram of a ranging result according to an embodiment of the present application is shown; Figure 4 A schematic diagram of a calibration scene according to an embodiment of the present application is shown; Figure 5 A schematic diagram of a step gauge set in Figure 4 is shown; Figure 6 A schematic diagram of a step gauge set and a step compensation block cooperating structure according to an embodiment of the present application is shown; Figure 7 A schematic flowchart of a through-thickness measurement method according to an embodiment of the present application is shown; Figure 8 A schematic block diagram of an electronic device according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0020] In order to make the purposes, technical solutions and advantages of the present application more apparent, the example embodiments according to the present application will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments of the present application, and it should be understood that the present application is not limited to the example embodiments described herein. Based on the embodiments of the present application described in the present application, all other embodiments obtained by those skilled in the art without creative labor should fall within the protection scope of the present application.

[0021] As described above, the through-thickness measurement method performs a through measurement by two ranging sensors installed in an up-down alignment. The measurement principle of the through-thickness measurement method can be expressed by the following formula: wherein, represents the thickness of the target object, represents the distance value measured by the upper distance sensor, represents the distance value measured by the lower distance sensor, represents the theoretical distance between the two sensors. This method is simple to operate and can quickly measure the thickness of objects such as steel plates. However, in actual working scenarios, there may be unknown deviations between the installation angle of the distance sensor and the ideal vertical measurement angle, and due to installation precision, there may be unknown position deviations in the installation height of the upper distance sensor and the lower distance sensor. Such deviations in installation angle and installation position seriously affect the thickness measurement accuracy. In view of this, the present application provides a calibration method, a transmission measurement thickness method, an electronic device and a medium, which can offset the influence of installation position, installation angle and the like by using the calibration parameters obtained by calibration, thereby helping to improve the thickness measurement accuracy. The method, electronic device and storage medium are described in detail below.

[0022] According to an aspect of an embodiment of the present application, a calibration method is provided, which is used for error calibration of a transmission measurement thickness system; the transmission measurement thickness system includes an upper distance sensor and a lower distance sensor located at the same vertical position, and the upper distance sensor is located above the lower distance sensor. Figure 1 A schematic flowchart of the calibration method of one embodiment of the present application is shown. As shown in Figure 1 The method can include steps S110, S120, S130 and S140.

[0023] In step S110, taking the abutting surface of any two adjacent blocks in the step block set as the step reference surface, the nominal distance sequence of the upper step surface and the lower step surface of the step block set is established based on the thickness nominal value of each block in the step block set, the step block set is arranged in a step shape by a plurality of blocks, and the nominal distance sequence includes the nominal distance of the upper step surface and the lower step surface of each block in the plurality of blocks.

[0024] A block is a reference gauge of length size, which is used for calibrating working gauges such as micrometers, and can be used as a length reference for size tracing in mechanical processing. Each block has a pair of measuring surfaces and two pairs of side surfaces, has multiple size specifications, and can be stacked and combined for use (referred to as "abutting"). The block has the following key performances: Deviation level: divided into 00, K, 0, 1, 2 levels according to manufacturing size deviation, reflecting the accuracy of the overall size of the block, the smaller the deviation, the higher the level, and the highest 00 level 0.5mm block deviation ±0.05um; Uncertainty level: Classified into 1 to 5 levels according to the measured dimensional uncertainty, reflecting the dimensional consistency of the gauge block at various points on the plane. The better the consistency, the higher the level, with the highest level 1 being 0.02um uncertainty for a 0.5mm gauge block; Fit: The measuring surfaces of the 00-grade gauge blocks are precision ground to a surface roughness Rz≤0.05um and a flatness not exceeding 0.03um, and the gauge blocks fit together without any gaps. Thermal expansion: Utilizing wear-resistant nickel-chromium alloy and tungsten steel materials, the standard coefficient of thermal expansion is 11.5 ± 1.0 × 10⁻⁶. -6 ℃ -1 .

[0025] In this embodiment, the inventors considered using a stepped gauge block group composed of multiple gauge blocks for distance calibration. The thickness gauge blocks are precisely sized and can serve as reference gauges, providing accurate nominal thickness values. Furthermore, the gap between the mating surfaces of the gauge blocks is 0.02~0.05µm, and the mating arrangement of the thickness gauge blocks forms upper and lower stepped surfaces based on thickness, allowing for simultaneous calibration of upper and lower sensors.

[0026] Figure 2 A schematic diagram of a stepped gauge block according to an embodiment of the present invention is shown. Figure 2 As shown, there are 4 gauge blocks, and the nominal thickness values ​​(which can be simply referred to as thickness) of the 4 gauge blocks are as follows: H 1. H 2. H 3 and H 4. The nominal distances (i.e., the theoretical distances from the transmitter of the upper ranging sensor to the upper stepped surface) of each of the four gauge blocks are as follows: U 1. U 2. U 3. U 4. The nominal distances (i.e., the theoretical distances from the transmitter of the lower ranging sensor to the lower stepped surface) of each of the four gauge blocks are as follows: D 1. D 2. D 3. D 4. Understandable. Figure 2 This is merely an example and not a limitation of the invention. The number of gauge blocks can be more or less than four, and the specific number can be determined according to the actual calibration scenario and equipment conditions. For example, if the ranging sensor itself has good linearity, only two gauge blocks may be used. Figure 2 In the embodiment shown, the mating surface between the second and third gauge blocks in the order from bottom to top is used as the step reference surface.

[0027] The thickness of each gauge block in a stepped gauge block group can be the same or different. The specific thickness can be selected according to actual needs. For example, when calibrating a thickness measurement system with a small minimum thickness measurement range, two gauge blocks with the thinnest thickness of 0.05 mm can be used.

[0028] In this embodiment, the stepped reference plane is a plane theoretically located between the two ranging sensors, that is, a plane located between the theoretical installation positions of the two ranging sensors. Based on this, two stepped surfaces (e.g., those on the same plane as the stepped reference plane) are also considered. Figure 2 The nominal distance between the upper stepped surface of the second gauge block and the lower stepped surface of the third gauge block is half the theoretical distance between the two range sensors (which can be expressed as...). G / 2). The nominal distances of other stepped surfaces can be determined based on the distance between the stepped surface and the step reference surface.

[0029] In step S120, the stepped gauge block group is controlled to translate so that the gauge blocks in the stepped gauge block group pass between the upper distance sensor and the lower distance sensor in sequence.

[0030] In practical working scenarios, the stepped gauge block group can be clamped by a clamping device on the guide rail, and the stepped gauge block group can be controlled to move along a preset direction so that each gauge block passes through the ranging point between the two ranging sensors in sequence. Those skilled in the art will understand the specific fixing and operation methods, which will not be described in detail.

[0031] In step S130, the translation distance of the stepped block group is obtained, as well as the measured distance of the upper stepped surface of the stepped block group collected by the upper distance sensor and the measured distance of the lower stepped surface of the stepped block group collected by the lower distance sensor during the translation process.

[0032] During the movement of the stepped gauge block group, each gauge block passes through the distance measurement point between the two distance measurement sensors in sequence. At this time, the two distance measurement sensors can collect the measured distance of each upper and lower stepped surface of the stepped gauge block group respectively. Figure 3 A schematic diagram illustrating the ranging results according to an embodiment of the present invention is shown. Figure 3 As shown, the gauge block along x The direction is translated, and the translation amount is adjusted accordingly. x As the distance increases, the bottommost gauge block passes the distance measurement point first, followed by the other gauge blocks in sequence. The measured distances corresponding to each upper stepped surface can be expressed as follows: , , , The measured distances corresponding to each lower step surface can be expressed as follows: , , , .

[0033] At step S140, based on the nominal distance, the measured distance of the upper step surface and the lower step surface of the step gauge block set and the translation amount of the step gauge block set, the measured distance is segmented linearly fitted to obtain the calibration parameters, including the first correction parameter for correcting the nominal distance of the upper step surface, the second correction parameter for correcting the nominal distance of the lower step surface, the upper sensor position deviation and the lower sensor position deviation, on the principle of minimizing the distance fitting error and the measured distance error.

[0034] Figure 4 A calibration scene schematic diagram according to one embodiment of the present application is shown. Figure 4 In the embodiment shown, the distance value measured by the upper distance sensor can be represented as d1, the distance value measured by the lower distance sensor can be represented as d2, and the theoretical distance between the upper distance sensor and the lower distance sensor can be represented as L. U In the embodiment shown, the distance value measured by the upper distance sensor can be represented as d1, the distance value measured by the lower distance sensor can be represented as d2, and the theoretical distance between the upper distance sensor and the lower distance sensor can be represented as L. D In the embodiment shown, the distance value measured by the upper distance sensor can be represented as d1, the distance value measured by the lower distance sensor can be represented as d2, and the theoretical distance between the upper distance sensor and the lower distance sensor can be represented as L. G The step reference surface is theoretically a plane between the two distance sensors. However, due to the installation accuracy of the two distance sensors, the two distance sensors actually have a deviation from the theoretical position with the step reference surface. As shown in Figure 4 The deviation of the theoretical distance between the upper distance sensor and the step reference surface can be represented as ΔL1, and the deviation of the theoretical distance between the lower distance sensor and the step reference surface can be represented as ΔL2. The deviation of the theoretical distance between the upper distance sensor and the step reference surface can be represented as ΔL1, and the deviation of the theoretical distance between the lower distance sensor and the step reference surface can be represented as ΔL2. The deviation of the theoretical distance between the upper distance sensor and the step reference surface can be represented as ΔL1, and the deviation of the theoretical distance between the lower distance sensor and the step reference surface can be represented as ΔL2. Figure 5 A schematic diagram of the step gauge block set in Figure 4 The inventor found through research that there is an unknown deviation between the upper distance sensor and the lower distance sensor and the ideal vertical measurement angle (i.e., the α and β The surface of the thickness gauge block cannot ensure consistency with the driving translation direction of the guide rail, is affected by the unknown installation angle deviation θ , and the aforementioned sensor position deviation , These problems can all affect the calibration accuracy. Therefore, the present application considers that the theoretical distance (i.e., the nominal distance) of each step surface during the movement of the step gauge block set is segmentedly fitted (this distance is referred to as the fitted distance), and the parameters in the fitting function are determined on the principle of minimizing the difference between the fitted distance and the measured distance, which are the calibration parameters.

[0035] In the above technical solution, the nominal distance and the measured distance of the upper and lower step surfaces of the step gauge block set are fitted, the calibration parameters can be accurately determined according to the difference between the two, thereby helping to correct the errors caused by the insufficient installation accuracy of the installation position, the installation angle, etc. of the distance sensor in the through-thickness measurement process, and improving the accuracy of the through-thickness measurement.

[0036] For example, the nominal distance of the step reference surface is determined based on the distance between the upper distance sensor and the lower distance sensor; for any step surface in the step gauge block group other than the step reference surface, the nominal distance of the step surface is determined based on the distance between the upper distance sensor and the lower distance sensor and the thickness of the gauge block between the step surface and the step reference surface.

[0037] As described above, when the two gauge blocks are arranged in abutment, the gap between the abutment surfaces is less than 0.05um, which can be ignored. In this case, for any step surface (upper step surface or lower step surface), the distance between the step surface and the step reference surface can be represented by the thickness of the gauge block between the two planes. This method can directly determine the nominal distance of each step surface based on the distance between the upper distance sensor and the lower distance sensor and the thickness of the gauge block between the step surface and the step reference surface without additional calculation, which is simple to operate and can greatly improve the calibration efficiency.

[0038] In the embodiment shown in FIG. 1, Figure 3 the step reference surface is the abutment surface between the second gauge block and the third gauge block in the order from bottom to top (it can be understood that this plane is the top surface of the second gauge block or the bottom surface of the third gauge block); and the nominal distance sequence of the upper step surface and the lower step surface of the step gauge block group is: ; In the formula, Dn represents the nominal distance sequence of the upper step surface of the step gauge block group; Dl represents the nominal distance sequence of the lower step surface of the step gauge block group; G D0 represents the theoretical distance between the upper distance sensor and the lower distance sensor; H 1, H 2, H 3, H 4 respectively represent the nominal values of the thicknesses of the respective gauge blocks in the order from bottom to top.

[0039] The above nominal distance sequence can more accurately represent the nominal distance of each step surface, thereby providing a more accurate basis for determining the calibration parameters in the subsequent steps.

[0040] For example, in step S140, based on the nominal distances of the upper step surface and the lower step surface of the step gauge block group, the measured distances, and the translation amount of the step gauge block group, the measured distances are segmented and linearly fitted with the principle of minimizing the distance and measured distance error, which can specifically include the following steps S141, S142, and S143.

[0041] In step S141, the translation amount of the step gauge block group and the nominal distance of the upper step surface of the step gauge block group are used to establish a segmented linear function of the upper step surface of the step gauge block group.

[0042] In step S142, a piecewise linear function of the lower step surface of the step gauge block set is established with the translation amount of the step gauge block set and the nominal distance of the lower step surface of the step gauge block set.

[0043] In step S143, piecewise linear functions of the upper step surface and the lower step surface of the step gauge block set are respectively fitted with the principle of minimizing the error between the fitted distance and the measured distance, to obtain the calibration parameters.

[0044] In some embodiments, the established piecewise linear function can be expressed as: ; The first row of the formula is the piecewise linear function of the upper step surface, and the second row of the formula is the piecewise linear function of the lower step surface. , n represents the total number of gauge blocks, and Figure 4 in the embodiment shown in the figure, n =4. represents the nominal distance of the i-th upper step surface, i represents the nominal distance of the i-th lower step surface, represents the fitted distance of the i-th upper step surface when translated to i represents the fitted distance of the i-th lower step surface when translated to represents the deviation between the upper distance measuring sensor and the theoretical distance G / 2 between the step reference surface, x represents the deviation between the lower distance measuring sensor and the theoretical distance G / 2 between the step reference surface, i represents the translation amount, represents the first correction parameter, x represents the second correction parameter, i represents the slope coefficient. After obtaining the piecewise linear functions of the two step surfaces, the piecewise linear functions of the upper step surface and the lower step surface of the step gauge block set can be respectively fitted with the principle of minimizing the error between the fitted distance and the measured distance. The total error of each fitted distance and the measured distance of the upper step surface can be expressed as: ; The total error of each fitted distance and the measured distance of the lower step surface can be expressed as:

[0045] . ; .

[0046] In the formula,​​​​ measured distance when translating to x the first upper step surface, i measured distance when translating to the first lower step surface. x i measured distance when translating to

[0047] In the above scheme, by minimizing the error between the fitting distance based on the translation amount and the nominal distance and the measured distance, the correction effect of the determined calibration parameters can be ensured, which helps to improve the accuracy of the shot thickness.

[0048] Exemplarily, when fitting the piecewise linear functions of the upper step surface and the lower step surface of the step amount block group, L2 constraint is used for fitting.

[0049] The L2 constraint can be expressed as: , , a, b, c are weight coefficients.

[0050] Exemplarily, after the fitting is completed, the method further includes: determining whether the L2 constraint term related to the first correction parameter is greater than a first preset threshold; determining whether the L2 constraint term related to the second correction parameter is greater than a second preset threshold; determining whether the L2 constraint term related to the slope coefficient is greater than a third preset threshold, the slope coefficient being the coefficient of the translation amount x When each L2 constraint is less than or equal to the corresponding preset threshold, the first correction parameter, the second correction parameter, the upper sensor position deviation and the lower sensor position deviation obtained in the current fitting are determined as the calibration parameters.

[0051] In the scheme of the present example, the L2 constraint term related to the first correction parameter is , the L2 constraint term related to the second correction parameter is , and the L2 constraint term related to the slope coefficient is .

[0052] In the above scheme, L2 constraint is used in the fitting process. L2 regularization adds the sum of squares of weight parameters as a penalty term in the loss function, effectively limiting the model complexity, preventing overfitting and improving the generalization ability. Its core mechanism lies in imposing smooth constraints on parameters to avoid extreme weight values, making the model more stable and robust to noise. In addition, L2 regularization improves numerical calculation stability by optimizing the convexity of the loss function, speeds up the convergence process and improves the calculation efficiency.

[0053] ​Illustratively, the method further comprises: when any L2 constraint term is greater than a corresponding preset threshold, outputting prompt information to remind the user to manually adjust; and after receiving an adjustment completion instruction, reacquiring the measured distances of the upper and lower step surfaces and performing piecewise linear fitting based on the newly acquired measured distances.

[0054] For ease of description, the preset threshold corresponding to the L2 constraint term related to the first correction parameter is referred to as a first preset threshold, the preset threshold corresponding to the L2 constraint term related to the second correction parameter is referred to as a second preset threshold, and the preset threshold corresponding to the L2 constraint term related to the slope coefficient is referred to as a third preset threshold.

[0055] The inventors have found in the research process that when the L2 constraint term is large, it indicates that the current angle deviation is large, and at this time, the correction effect of the parameter alone may not be able to well calibrate the thickness measurement result. Therefore, in the scheme of the present application, when the L2 constraint term is large, the user is reminded to manually correct, so that the manual correction method can be combined to reduce each L2 constraint term to a small value, thereby reducing the fitting difficulty and improving the fitting efficiency. The parameter correction + manual intervention method can better improve the thickness measurement accuracy.

[0056] In the above example, after the manual adjustment is completed, the measured distances can be reacquired and re-fitted. That is, after the manual adjustment, steps S120, S130 and S140 are performed again to obtain the calibration parameters after adjustment.

[0057] In some embodiments, when any L2 constraint term is greater than a corresponding preset threshold, the prompt information is outputted, including: when the L2 constraint term related to the first correction parameter is greater than the first preset threshold, first prompt information is outputted, the first prompt information being used to indicate that the upper distance measuring sensor has an angle deviation; when the L2 constraint term related to the second correction parameter is greater than the second preset threshold, second prompt information is outputted, the second prompt information being used to indicate that the lower distance measuring sensor has an angle deviation; and when the L2 constraint term related to the slope coefficient is greater than the third preset threshold, third prompt information is outputted, the third prompt information being used to indicate that there is an angle deviation between the length direction of the step block group and the translation direction.

[0058] The inventors have further found that when the L2 constraint term related to the first correction parameter is large, it indicates that the upper distance measuring sensor has a large angle deviation; when the L2 constraint term related to the second correction parameter is large, it indicates that the lower distance measuring sensor has a large angle deviation; and when the L2 constraint term related to the slope coefficient is large, it indicates that there is a large angle deviation between the length direction of the step block group and the translation direction. In the scheme of the present embodiment, different prompt information is outputted in different cases, which can facilitate the user to quickly locate the position that needs to be manually corrected, which helps to improve the calibration efficiency.

[0059] In this document, the prompts include, but are not limited to, audio, visual, and text prompts. For example, when the L2 constraint term related to the first correction parameter exceeds a first preset threshold, an audio prompt stating "The upper ranging sensor has an angular deviation" may be emitted. Another example is that when the L2 constraint term related to the first correction parameter exceeds the first preset threshold, a red light may flash (different colors of light may flash for different prompts). Yet another example is that when the L2 constraint term related to the first correction parameter exceeds the first preset threshold, the text message "The upper ranging sensor has an angular deviation" may be sent to the user terminal or displayed on a large screen. Further details are omitted.

[0060] For example, after obtaining the calibration parameters, the method further includes: calibrating the measured distance using the calibration parameters to obtain the calibration distance between the upper and lower stepped surfaces; calculating the thickness measurement value of each gauge block in the stepped gauge block group based on the calibration distance between each upper stepped surface and the corresponding lower stepped surface; calculating the calibration deviation based on the thickness measurement value and thickness (the actual thickness value) of each gauge block in the stepped gauge block group; determining that the calibration parameters are qualified when the calibration deviation is less than the deviation threshold; otherwise, re-performing piecewise linear fitting on the measured distance.

[0061] In some embodiments, the calibration distance of the upper stepped surface It can be represented as: ; Calibration distance of the upper stepped surface It can be represented as: .

[0062] After calibration, the thickness measurement value of each gauge block in the stepped gauge block group It can be calculated using the following formula: .

[0063] After obtaining the calibrated thickness measurement value for each gauge block, the standard deviation can be statistically calculated based on the difference between the measured thickness value and the nominal thickness value for each gauge block. In one embodiment, this standard deviation... It can be calculated using the following formula: .

[0064] After obtaining the calibration parameters, the above technical solution can use the calibration parameters to correct the measured distance of each stepped surface, calculate the thickness measurement value of each gauge block based on the correction result, and evaluate the calibration accuracy based on the difference between the thickness measurement value and the actual thickness value. This method can better verify the effectiveness of the calibration parameters, improve the accuracy of the final obtained calibration parameters, and improve the accuracy of through-beam thickness measurement.

[0065] Exemplarily, the second step compensation block is arranged on the step block group, the first step compensation block has a bottom surface abutting against a top surface of a lowermost block in the step block group, and has a top surface flush with a top surface of an uppermost block in the step block group; the second step compensation block has a top surface abutting against a bottom surface of the uppermost block in the step block group, and has a bottom surface flush with the bottom surface of the lowermost block in the step block group.

[0066] The inventor also found in the research process that, due to the step block group used in the calibration process, the entire assembly structure can be unstable during clamping and moving, and this instability can cause the parallelism deviation of the block to increase along the step arrangement direction. In view of this, the inventor considers adding two step compensation blocks to improve the stability of the overall assembly structure. The step compensation block can be machined from a block that meets the thickness requirement, which can ensure good abutment of the step compensation block and the block surface. Figure 6 A schematic diagram of a step block group and a step compensation block cooperation structure according to an embodiment of the present application is shown. As shown in Figure 6 The left step compensation block is the first step compensation block, the bottom surface of the step compensation block abuts against the top surface of the lowermost block in the step block group, and the top surface is flush with the top surface of the uppermost block. The right step compensation block is the second step compensation block, the top surface of the step compensation block abuts against the bottom surface of the uppermost block in the step block group, and the bottom surface is flush with the bottom surface of the lowermost block. Thus, the top surface of the first step compensation block and the top surface of the uppermost block can serve as an upper clamping surface, and the bottom surface of the second step compensation block and the bottom surface of the lowermost block can serve as a lower clamping surface. In actual scenarios, the upper clamping surface and the lower clamping surface can be clamped by the upper clamping block and the lower clamping block of the moving mechanism, respectively.

[0067] The above scheme can form a stable overall assembly structure by adding a step compensation block and a clamping structure for clamping the step block group, thereby avoiding the parallelism deviation of the thickness block increasing along the step arrangement direction.

[0068] According to another aspect of the embodiment of the present application, a method for calibrating a thickness measurement system is provided. The thickness measurement system includes an upper distance sensor and a lower distance sensor located at the same vertical position, and the upper distance sensor is located above the lower distance sensor. Figure 7 A schematic flowchart of a method for calibrating a thickness measurement system according to an embodiment of the present application is shown. As shown in Figure 7 The method includes steps S710 and S720.

[0069] In step S710, the calibration method described above is used for calibration to obtain calibration parameters.

[0070] At step S720, the thickness of the target object is determined based on at least the calibration parameter and the distances measured by the upper distance sensor and the lower distance sensor respectively.

[0071] For example, the calibration parameter is , , and . The distance measured by the upper distance sensor is , and the distance measured by the lower distance sensor is . In this case, the thickness of the target object can be determined by the following formula: .

[0072] The above scheme can improve the accuracy of the thickness measurement result by correcting the measurement result with the calibration parameter obtained by the pre-calibration.

[0073] For example, the temperature of the gauge block set in the calibration process is the ideal working temperature; and the thickness of the target object is determined based on at least the calibration parameter and the distances measured by the upper distance sensor and the lower distance sensor respectively, including: determining the thickness of the target object based on the calibration parameter, the difference between the current temperature and the ideal working temperature, and the distances measured by the upper distance sensor and the lower distance sensor respectively.

[0074] It can be understood that the ideal working temperature of the gauge block in the calibration process is 20℃. In the scheme of the present example, it is considered that the calibration is performed when the gauge block reaches the ideal working temperature. At the same time, it is considered that the temperature during the actual measurement may be different from the ideal working temperature, and therefore the current temperature is introduced when determining the thickness of the target object, so that the thickness of the target object at the ideal working temperature can be obtained.

[0075] In some embodiments, the thickness of the target object is determined based on the calibration parameter, the difference between the current temperature and the ideal working temperature, and the distances measured by the upper distance sensor and the lower distance sensor respectively, including: determining the thickness of the target object based on the calibration parameter and the distances measured by the upper distance sensor and the lower distance sensor respectively; and temperature compensating the determined thickness by using the difference between the current temperature and the ideal working temperature, so as to obtain the thickness of the target object at the ideal working temperature.

[0076] In some embodiments, the thickness of the target object at the ideal working temperature is obtained by temperature compensating the determined thickness by using the difference between the current temperature and the ideal working temperature, including: obtaining the thickness of the target object at the ideal working temperature by the following formula : ; wherein represents the linear expansion coefficient of the target object.

[0077] The above solution, through temperature compensation, can more accurately determine the thickness of the target object at the ideal operating temperature, thus improving the accuracy of the results.

[0078] According to another aspect of the present invention, an electronic device is also provided. Figure 8 A schematic block diagram of an electronic device according to an embodiment of the present invention is shown. Figure 8 As shown, the electronic device 800 includes a processor 810 and a memory 820. The memory 820 stores a computer program, which the processor 810 executes to implement the calibration method or the through-beam thickness measurement method described above.

[0079] According to another aspect of the present invention, a computer-readable storage medium is also provided. This storage medium stores a computer program / instructions, which, when executed by a processor, implement the calibration method or the through-beam thickness measurement method described above. The storage medium may, for example, include a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a portable compact disc read-only memory (CD-ROM), a USB memory, or any combination of the above storage media. The computer-readable storage medium may be any combination of one or more computer-readable storage media.

[0080] Those skilled in the art will readily understand the implementation structure, working principle, and beneficial effects of electronic devices and computer-readable storage media by reading the above methods. For the sake of brevity, further details will not be elaborated here.

[0081] Although exemplary embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above exemplary embodiments are merely illustrative and are not intended to limit the scope of the invention. Various changes and modifications can be made therein by those skilled in the art without departing from the scope and spirit of the invention. All such changes and modifications are intended to be included within the scope of the invention as claimed in the appended claims.

[0082] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0083] In several embodiments provided by the present application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the above-described apparatus embodiments are merely schematic. For example, the division of units is merely a logical function division. In actual implementation, another division manner can be used, for example, a plurality of units or components can be combined or integrated into another apparatus, or some features can be omitted or not implemented.

[0084] In the specification provided herein, a large number of specific details are described. However, it can be understood that the embodiments of the present application can be practiced without these specific details. In some examples, well-known methods, structures and techniques are not described in detail in order not to obscure the understanding of the present specification.

[0085] Similarly, it should be appreciated that, in the description of the exemplary embodiments of the present application, various features of the present application are sometimes grouped together in a single embodiment, figure, or description of a related aspect. This is done for the purpose of clarity in understanding the present application. However, it should be understood that this method of grouping is not necessarily meant to reflect a physical, logical, or any other type of relationship between features of the application. Rather, the described features can be combined in any manner or in any combination of aspects of the application.

[0086] Those skilled in the art can understand that, except for the mutual exclusion between features, all features disclosed in the specification (including the accompanying claims, abstract and drawings) and all processes or units of any method or apparatus disclosed in this way can be combined in any combination. Unless explicitly stated otherwise, each feature disclosed in the specification (including the accompanying claims, abstract and drawings) can be replaced by an alternative feature that provides the same, equivalent or similar purpose.

[0087] In addition, those skilled in the art can understand that, although some embodiments described herein include certain features rather than others included in other embodiments, the combination of features of different embodiments means that it is within the scope of the present application and forms different embodiments. For example, in the claims, any one of the claimed embodiments can be used in any combination.

[0088] Various component embodiments of the present application can be implemented in hardware, or as software modules running in one or more processors, or in combinations thereof. As will be appreciated by one skilled in the art, a microprocessor or digital signal processor (DSP) can be used in practice to implement some or all of the functionality of some of the modules in the electronic device according to embodiments of the present application. The present application can also be implemented as an apparatus program (e.g., computer program and computer program product) for performing part or all of the methods described herein. Such a program implementing the present application can be stored on a computer readable medium, or can have one or more signals. Such signals can be downloaded from an Internet website, or provided on a carrier medium, or in any other form.

[0089] It should be noted that the above-mentioned embodiments illustrate rather than limit the application, and that one skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word 'comprising' does not exclude the presence of elements or steps other than those listed in a claim. The word 'a' or 'an' preceding an element does not exclude the presence of a plurality of such elements. The application can be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In a unitary claim, several of the devices, apparatuses or means, if more than one is recited, can be implemented by one and the same item of hardware. The use herein of the term implying a certain order should not be construed as implying any order. Such terms can be interpreted as nouns.

[0090] The above description is only specific embodiments of the present application or specific explanations of the specific embodiments, and the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, and all of them should be covered within the protection scope of the present application. The protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A calibration method, characterized in that, Error calibration for a through-beam thickness measurement system; the through-beam thickness measurement system includes an upper distance sensor and a lower distance sensor located at the same vertical position, the upper distance sensor being located above the lower distance sensor; the method includes: Using the mating surfaces of any two adjacent gauge blocks in the stepped gauge block group as the stepped reference surface, and based on the nominal thickness values ​​of each gauge block in the stepped gauge block group, establish the nominal distance sequence of the upper and lower stepped surfaces of the stepped gauge block group. The stepped gauge block group consists of multiple gauge blocks mated and arranged in a stepped shape. The nominal distance sequence includes the nominal distance of the upper and lower stepped surfaces of each of the multiple gauge blocks. Control the translation of the stepped gauge block group so that the gauge blocks in the stepped gauge block group pass between the upper distance sensor and the lower distance sensor in sequence; The translation distance of the stepped gauge block group is obtained, as well as the measured distance of the upper stepped surface of the stepped gauge block group collected by the upper distance sensor and the measured distance of the lower stepped surface of the stepped gauge block group collected by the lower distance sensor during the translation process. Based on the nominal distance and measured distance of the upper and lower stepped surfaces of the stepped gauge block group, as well as the translation amount of the stepped gauge block group, the measured distance is piecewise linearly fitted to obtain calibration parameters, with the principle of minimizing the error between the fitted distance and the measured distance. The calibration parameters include a first correction parameter for correcting the nominal distance of the upper stepped surface, a second correction parameter for correcting the nominal distance of the lower stepped surface, the upper sensor position deviation, and the lower sensor position deviation.

2. The method according to claim 1, characterized in that, The nominal distance of the stepped reference surface is determined based on the distance between the upper ranging sensor and the lower ranging sensor; for any stepped surface in the stepped gauge block group other than the stepped reference surface, the nominal distance of the stepped surface is determined based on the distance between the upper ranging sensor and the lower ranging sensor and the thickness of the gauge block between the stepped surface and the stepped reference surface.

3. The method according to claim 2, characterized in that, The stepped gauge block group contains four gauge blocks. The stepped reference surface is the mating surface between the second and third gauge blocks in a bottom-to-top order. The nominal distance sequence between the upper and lower stepped surfaces of the stepped gauge block group is as follows: In the formula, This represents the nominal distance sequence of the stepped surfaces on the stepped block group; This represents the nominal distance sequence of the lower stepped surface of the stepped block group; G This represents the theoretical distance between the upper ranging sensor and the lower ranging sensor; H 1. H 2. H 3. H 4 represents the nominal thickness value of each of the multiple gauge blocks in order from bottom to top.

4. The method according to claim 1, characterized in that, Based on the nominal distance and measured distance between the upper and lower stepped surfaces of the stepped gauge block group, as well as the translation amount of the stepped gauge block group, and with the principle of minimizing the error between the fitted distance and the measured distance, piecewise linear fitting is performed on the measured distance, including: A piecewise linear function of the upper stepped surface of the stepped block group is established using the translation amount of the stepped block group and the nominal distance of the upper stepped surface of the stepped block group. A piecewise linear function of the lower step surface of the stepped block group is established using the translation amount of the stepped block group and the nominal distance of the lower step surface of the stepped block group. Based on the principle of minimizing the error between the fitted distance and the measured distance, piecewise linear functions of the upper and lower stepped surfaces of the stepped block group are fitted respectively to obtain the calibration parameters.

5. The method according to claim 4, characterized in that, When fitting the piecewise linear functions of the upper and lower stepped surfaces of the stepped block group, L2 constraints are used for fitting. Preferably, after the fitting is completed, the method further includes: Determine whether the L2 constraint term related to the first correction parameter is greater than the first preset threshold; Determine whether the L2 constraint term related to the second correction parameter is greater than the second preset threshold; Determine whether the L2 constraint term related to the slope coefficient is greater than a third preset threshold, wherein the slope coefficient is the coefficient of the translation amount; When each L2 constraint is less than or equal to the corresponding preset threshold, the first correction parameter, the second correction parameter, the upper sensor position deviation and the lower sensor position deviation obtained in the current fitting are determined as the calibration parameters. Preferably, the method further includes: When any L2 constraint term exceeds the corresponding preset threshold, a prompt message is output to remind the user to make manual adjustments; After receiving the adjustment completion instruction, the measured distance between the upper stepped surface and the lower stepped surface is reacquired, and piecewise linear fitting is performed based on the latest acquired measured distance. Preferably, the step of outputting a prompt message when any L2 constraint term is greater than the corresponding preset threshold includes: When the L2 constraint term related to the first correction parameter is greater than the first preset threshold, a first prompt message is output, which indicates that there is an angular deviation in the upper ranging sensor. When the L2 constraint term related to the second correction parameter is greater than the second preset threshold, a second prompt message is output, which indicates that the lower ranging sensor has an angular deviation. When the L2 constraint term related to the slope coefficient is greater than the third preset threshold, a third prompt message is output. The third prompt message is used to indicate that there is an angular deviation between the length direction and the translation direction of the stepped block group.

6. The method according to any one of claims 1-5, characterized in that, After obtaining the calibration parameters, the method further includes: The measured distance is calibrated using the calibration parameters to obtain the calibrated distance between the upper and lower stepped surfaces. Based on the calibration distance between each upper stepped surface and the corresponding lower stepped surface, the calibrated thickness measurement value of each block in the stepped block group is calculated. The calibration deviation is calculated based on the calibrated thickness measurement and nominal thickness value of each gauge block in the stepped gauge block group. When the calibration deviation is less than the deviation threshold, the calibration parameter is determined to be qualified. Otherwise, the measured distance is re-fitted piecewise linearly.

7. The method according to any one of claims 1-5, characterized in that, The stepped gauge block group is provided with a second stepped compensation block of the first stepped compensation block; The bottom surface of the first step compensation block is lapped with the top surface of the lowest step block in the step block group, and the top surface of the first step compensation block is flush with the top surface of the highest step block in the step block group. The top surface of the second step compensation block is lapped with the bottom surface of the uppermost block in the step block group, and the bottom surface of the second step compensation block is flush with the bottom surface of the lowermost block in the step block group.

8. A method for measuring thickness by through-beam projection, characterized in that, For use in a through-beam thickness measurement system; the through-beam thickness measurement system includes an upper distance sensor and a lower distance sensor located at the same vertical position, the upper distance sensor being located above the lower distance sensor; the method includes: The calibration is performed using the method described in any one of claims 1-7 to obtain calibration parameters; The thickness of the target object is determined based at least on the calibration parameters and the distances measured by the upper and lower ranging sensors, respectively. Preferably, the temperature of the gauge blocks in the stepped gauge block group is the ideal operating temperature during the calibration process; determining the thickness of the target object based at least on the calibration parameters and the distances measured by the upper and lower ranging sensors includes: The thickness of the target object is determined based on the calibration parameters, the difference between the current temperature and the ideal operating temperature, and the distances measured by the upper and lower ranging sensors.

9. An electronic device, characterized in that, It includes a processor and a memory, wherein the memory stores a computer program, and the processor is used to execute the computer program to implement the method as claimed in any one of claims 1-7 or claim 8.

10. A computer-readable storage medium, characterized in that, The system contains a computer program / instructions that, when executed by a processor, implement the method as described in any one of claims 1-7 or claim 8.

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