Metal component thickness measuring method based on eddy current testing

Abstract

The invention provides a metal component thickness measurement method based on eddy current detection, and the method comprises the steps: building an eddy current sensor which is coaxial and excites two receiving coils, forming two pairs of excitation-receiving coil units with different lift-off distances, and measuring an eddy current response signal of a metal component through a sweep frequency eddy current mode; calculating the mean value of the response signals, obtaining a differential mutual inductance response curve through subtraction with the mean value, and analyzing the frequency and the mutual inductance value corresponding to the cross point of the curve; establishing an eddy current response analysis theoretical model, and setting electromagnetic parameters of the metal component and geometric parameters of the sensor; and inputting the frequency and the mutual inductance value of the cross point into the analytical model, converting a thickness measurement problem of the metal component into a least square optimization problem, inverting the thickness by using an improved Newton iterative algorithm until a convergence condition is met, and finally outputting a thickness measurement result of the metal component. According to the method, accurate measurement of the thickness of the metal component can be realized, and the method is not influenced by fluctuation change of the lift-off distance.

Description

Technical Field

[0001] The present application relates to the technical field of non-contact dimension measurement using electromagnetic eddy currents, and in particular to a method for measuring the thickness of a metal component based on eddy current detection. Background Art

[0002] Metal components, such as the base and bracket of power equipment, provide a stable support for other equipment in the power system. These components usually have high strength and rigidity, and can withstand the weight of the equipment itself as well as various forces and vibrations during operation, ensuring the stability and safety of the entire power system. When the component is thinned due to corrosion, etc., its cross-sectional area is reduced, resulting in a decrease in bearing capacity. In the power system, this may make the component more susceptible to deformation or damage when subjected to normal or abnormal loads. In addition, for metal components that need to withstand complex loads such as bending moment and shear force, the thinning of thickness will further reduce its stability. This may cause the component to be more prone to instability when subjected to external forces, affecting the overall stability of the power system. Therefore, it is very important to detect the thickness of metal components.

[0003] Eddy current testing technology is non-contact and can measure thickness without damaging the surface of metal components. However, in the actual testing process, if the lift-off distance between the eddy current testing probe and the surface of the metal component being tested fluctuates, the intensity of the eddy current signal will also fluctuate accordingly, which will affect the accuracy and stability of the eddy current testing results. Summary of the invention

[0004] The present application aims to solve one of the technical problems in the related art at least to some extent.

[0005] To this end, the first objective of the present application is to propose a method for measuring the thickness of a metal component based on eddy current detection.

[0006] The second objective of the present application is to provide a metal component thickness measurement device based on eddy current detection.

[0007] The third objective of the present application is to provide an electronic device.

[0008] A fourth objective of the present application is to provide a computer-readable storage medium.

[0009] A fifth object of the present application is to provide a computer program product.

[0010] To achieve the above-mentioned purpose, the first embodiment of the present application proposes a method for measuring the thickness of a metal component based on eddy current detection, comprising:

[0011] S1. Build an eddy current sensor consisting of a coaxial excitation coil and two receiving coils, wherein the middle coil is the excitation coil, and the bottom and end coils are receiving coils, forming two pairs of excitation-receiving coil units with different lifting distances;

[0012] S2, using the constructed eddy current sensor to detect the metal component in a swept frequency eddy current mode, and obtaining eddy current response signals M1(ω) and M2(ω) caused by the metal component;

[0013] S3. Calculate the mean values ​​m1 and m2 of the two groups of eddy current response signals respectively, and obtain two differential mutual inductance response curves by subtracting the original frequency sweep signal from the mean value. Calculate the frequency f corresponding to the intersection of the two differential mutual inductance response curves. c and mutual inductance value M0;

[0014] S4, establishing an eddy current response analytical theoretical model, setting the electromagnetic parameters of the metal component and the geometric parameters of the eddy current sensor;

[0015] S5, the frequency of the crossover point f c The mutual inductance value M0 is input into the eddy current response analytical theoretical model, the thickness measurement problem of the metal component is converted into a least squares optimization problem, and an improved Newton iterative algorithm is used to solve it;

[0016] Step S5 is repeatedly performed until the difference between two adjacent iteration results is less than a preset threshold or the maximum number of iterations is reached, and finally the thickness measurement result of the metal component is output.

[0017] Optionally, the eddy current sensor is designed as a coaxial one excitation two receiving coil structure, wherein:

[0018] The three coils are the same size;

[0019] The middle coil is the excitation coil, and the bottom coil and the end coil are the receiving coils, which is equivalent to constructing two pairs of mutual inductance eddy current sensors with different lifting distances.

[0020] The lifting distance of the first pair of excitation-receiving coils is l0, and the lifting distance of the second pair of excitation-receiving coils is l0+g+h.

[0021] Optionally, the mean values ​​m1 and m2 of the two groups of eddy current response signals are calculated respectively, and the original frequency sweep signal is subtracted from the mean value to obtain two differential mutual inductance response curves, and the frequency f corresponding to the intersection of the two differential mutual inductance response curves is calculated. c And mutual inductance value M0, including:

[0022] Calculate the mean values ​​of the eddy current response signals M1(ω) and M2(ω), denoted as m1 and m2 respectively;

[0023] Subtract the eddy current response signals M1(ω) and M2(ω) from the mean values ​​m1 and m2 respectively to obtain two differential mutual inductance response curves M1(ω)-m1 and M2(ω)-m2;

[0024] Draw the differential mutual inductance response curves M1(ω)-m1 and M2(ω)-m2, obtain the intersection point where the mutual inductance values ​​of the two curves are equal, and calculate the frequency f corresponding to the intersection point of the two differential mutual inductance response curves c And mutual inductance value M0.

[0025] Optionally, in the established eddy current response analytical theoretical model, the electromagnetic parameters of the metal component include conductivity σ, and the geometric parameters of the eddy current sensor include: inner diameter r1 and outer diameter r2 of the coil, height h of the coil, and coil spacing g.

[0026] Optionally, the expression of the eddy current response analytical theoretical model is:

[0027]

[0028] Where:

[0029]

[0030] Wherein, M(ω) is the mutual inductance value of the eddy current response at the angular frequency ω; K is the signal amplitude coefficient of the sensor, where N is the number of coil turns and μ0 is the vacuum permeability; P(α) is a function of the coil geometric parameters, where J1(t) is a first-order Bessel function and t is an integral variable; α is an integral variable representing the wave number; φ(α) is a function related to the electromagnetic properties and thickness of the metal component; α1 is a complex wave number and j is an imaginary unit; d is the thickness of the metal component.

[0031] Optionally, the frequency f of the crossover point c The mutual inductance value M0 is input into the eddy current response analytical theoretical model, the thickness measurement problem of the metal component is converted into a least squares optimization problem, and the improved Newton iterative algorithm is used to solve it, including:

[0032] The frequency f of the intersection of the two differential mutual inductance response curves c and the mutual inductance value M0 are input into the eddy current response analytical theoretical model;

[0033] The thickness measurement problem of the metal component is transformed into a least squares problem, and the objective function F(d) is defined as:

[0034]

[0035] In the formula, M(ω c , d) is the crossover angular frequency ω calculated based on the eddy current response analytical theoretical modelc Below, the differential mutual inductance value corresponding to thickness d;

[0036] Calculate the Jacobian matrix J of Newton's iterative algorithm using the difference quotient method d , the expression is:

[0037]

[0038] Where Δd is the thickness step;

[0039] The thickness value d is updated according to the following iterative formula:

[0040]

[0041] Where, d ′ is the thickness value of the metal component after updating, is the inverse of the Jacobian matrix, which is used to correct the thickness value.

[0042] To achieve the above-mentioned purpose, the second embodiment of the present application proposes a metal component thickness measurement device based on eddy current detection, comprising:

[0043] A sensor building module is used to build an eddy current sensor consisting of a coaxial one excitation and two receiving coils, wherein the middle coil is the excitation coil, and the bottom and end coils are receiving coils, forming two pairs of excitation-receiving coil units with different lifting distances;

[0044] A detection module, used to detect the metal component in a swept frequency eddy current mode using the constructed eddy current sensor, and obtain eddy current response signals M1(ω) and M2(ω) caused by the metal component;

[0045] The calculation module is used to calculate the mean values ​​m1 and m2 of the two groups of eddy current response signals respectively, and to obtain two differential mutual inductance response curves by subtracting the original frequency sweep signal from the mean value, and to calculate the frequency f corresponding to the intersection of the two differential mutual inductance response curves. c and mutual inductance value M0;

[0046] A model building module, used to build an eddy current response analytical theoretical model, set the electromagnetic parameters of the metal component and the geometric parameters of the eddy current sensor;

[0047] The solver module is used to convert the frequency f of the crossover point c The mutual inductance value M0 is input into the eddy current response analytical theoretical model, the thickness measurement problem of the metal component is converted into a least squares optimization problem, and an improved Newton iterative algorithm is used to solve it;

[0048] The loop module is used to repeatedly execute the above input and solution process until the difference between two adjacent iteration results is less than a preset threshold or the maximum number of iterations is reached, and finally output the thickness measurement result of the metal component.

[0049] To achieve the above-mentioned purpose, the third aspect of the present application provides an electronic device, including: a processor, and a memory communicatively connected to the processor;

[0050] The memory stores computer-executable instructions;

[0051] The processor executes the computer-executable instructions stored in the memory to implement the method as described in any one of the first aspects.

[0052] To achieve the above-mentioned purpose, the fourth aspect of the present application proposes a computer-readable storage medium, in which computer-readable storage medium is stored computer execution instructions, and when the computer execution instructions are executed by a processor, they are used to implement the method as described in any one of the first aspects.

[0053] To achieve the above-mentioned purpose, the fifth aspect of the present application proposes a computer program product, which implements any method in the first aspect when executed by a processor.

[0054] The technical solution provided by the embodiments of the present application brings at least the following beneficial effects:

[0055] The method can realize accurate measurement of the thickness of metal components and is not affected by fluctuations in the lift-off distance.

[0056] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0058] Figure 1 A schematic diagram of a process of measuring the thickness of a metal component based on eddy current detection provided in an embodiment of the present application;

[0059] Figure 2 A schematic diagram of an eddy current sensor composed of one coaxial excitation coil and two receiving coils provided in an embodiment of the present application;

[0060] Figure 3 A waveform diagram of the response signal of the coaxial eddy current sensor at different lift-off distances provided in the embodiment of the present application;

[0061] Figure 4The differential response signal waveform diagram of the coaxial eddy current sensor at different lift-off distances provided in the embodiment of the present application;

[0062] Figure 5 A schematic structural diagram of a metal component thickness measurement device based on eddy current detection provided in an embodiment of the present application. DETAILED DESCRIPTION

[0063] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0064] In view of the problems existing in the prior art, the present invention provides a method for measuring the thickness of a metal component based on eddy current detection. Figure 1 The following is a schematic diagram of a process for measuring the thickness of a metal component based on eddy current detection provided in an embodiment of the present application. Figure 1 As shown, the method comprises the following steps:

[0065] S1. Build an eddy current sensor consisting of a coaxial excitation and two receiving coils, where the middle coil is the excitation coil, and the bottom and end coils are receiving coils, forming two pairs of excitation-receiving coil units with different lifting distances.

[0066] The embodiment of the present application adopts an eddy current sensor composed of a coaxial excitation coil and two receiving coils. Figure 2 As shown in the figure, the design structure of the sensor is: the middle coil is the excitation coil, the bottom coil and the end coil are the receiving coils, the three sets of coils are of the same size, the axes are aligned, and they are coaxially arranged. The excitation coil is used to generate an eddy current field in the metal component, and the receiving coil is used to detect the response signal caused by the eddy current field in the metal component.

[0067] With this design, the eddy current sensor constructs two pairs of excitation-receiving coil units with different lift-off distances:

[0068] The first pair of coils: the excitation coil and the bottom receiving coil, the lifting distance is l0;

[0069] The second pair of coils: the excitation coil and the end receiving coil, the lifting distance is l0+g+h, where g represents the coil spacing and h represents the coil height.

[0070] It can be understood that the two pairs of excitation-receiving coil units can detect eddy current response signals at different depths differently due to the different lift-off distances, thereby improving the accuracy and robustness of the measurement. The two pairs of coils are equivalent to constructing two pairs of mutual inductance eddy current sensors with different lift-off distances, so that the design can better suppress the influence of lift-off distance fluctuations on the measurement results.

[0071] In addition, the parameters of the coil (such as the inner diameter, outer diameter, height, etc. of the coil) are optimized to ensure a balance between signal strength and resolution accuracy, thereby improving detection performance.

[0072] S2. Use the constructed eddy current sensor to detect the metal components in the swept frequency eddy current mode to obtain the eddy current response signals M1(ω) and M2(ω) caused by the metal components.

[0073] In the embodiment of the present application, the constructed eddy current sensor is used to detect the metal component in the swept frequency eddy current mode to obtain the eddy current response signals M1(ω) and M2(ω) caused by the metal component. Specifically, the stacked eddy current sensor is placed above the metal component to be tested, and a fixed distance is maintained between the sensor and the surface of the metal component. The alternating current is injected in a swept frequency manner through the excitation coil, and the excitation frequency range is set to 10Hz to 1MHz to cover the eddy current response from the surface to the deep layer.

[0074] It should be noted that the essence of the measurement is to detect the characteristic curve of the change of coil impedance with frequency. By measuring the impedance change of the receiving coil at different frequencies, the eddy current response signals of the first pair of excitation-receiving coil units and the second pair of excitation-receiving coil units can be obtained respectively. These signals are as follows: Figure 3 As shown, the typical frequency domain characteristics of the eddy current response signal are shown, reflecting the electromagnetic response of the metal component at different frequencies.

[0075] This swept-frequency eddy current mode can cover eddy current signals from the surface to deep layers, effectively improving the accuracy and stability of thickness measurement, and providing a high-quality data foundation for subsequent signal processing and thickness inversion.

[0076] S3. Calculate the mean values ​​m1 and m2 of the two groups of eddy current response signals respectively, and obtain two differential mutual inductance response curves by subtracting the original frequency sweep signal from the mean value. Calculate the frequency f corresponding to the intersection of the two differential mutual inductance response curves. c And mutual inductance value M0.

[0077] It should be noted that the response signals M1(ω) and M2(ω) measured by the eddy current sensor in the swept frequency eddy current mode will be significantly affected by the change in the lift-off distance, which is mainly manifested as the difference in signal amplitude.

[0078] In the embodiment of the present application, the mean values ​​m1 and m2 of the eddy current response signals M1(ω) and M2(ω) are calculated respectively, and the original frequency sweep signal is processed to obtain two differential mutual inductance response curves, and then the characteristic frequency f corresponding to the intersection of the curves is analyzed. c And mutual inductance value M0. The specific steps are as follows:

[0079] Firstly, the mean values ​​m1 and m2 of the two groups of eddy current response signals in the entire frequency sweep range are calculated.

[0080] Then, the eddy current response signals M1(ω) and M2(ω) are subtracted from their mean values ​​m1 and m2 respectively to obtain two differential mutual inductance response curves M1(ω)-m1 and M2(ω)-m2. This differential processing can effectively remove the direct impact of the lift-off distance change on the signal amplitude and highlight the phase and frequency characteristics of the signal.

[0081] Next, the calculated differential mutual inductance response curves M1(ω)-m1 and M2(ω)-m2 are plotted in the same figure, as shown in Figure 4 The two curves reflect the differential response characteristics of the two pairs of coil units, showing obvious crossover characteristics.

[0082] Finally, the intersection of the two differential mutual inductance response curves M1(ω)-m1 and M2(ω)-m2 is analyzed to determine that the mutual inductance values ​​of the two curves at the intersection are equal, and the characteristic frequency f corresponding to the intersection is calculated. c (angular frequency is ω c ) and mutual inductance value M0.

[0083] It can be understood that the characteristic frequency f of the crossover point c The mutual inductance value M0 is the key parameter for measuring the thickness of metal components. The subsequent steps will use these parameters combined with the analytical theoretical model to perform thickness inversion calculation. Figure 4 ) intuitively demonstrates that the influence of lift-off distance changes on signal amplitude is effectively suppressed, providing a reliable basis for subsequent data analysis.

[0084] S4. Establish an analytical theoretical model of eddy current response and set the electromagnetic parameters of metal components and the geometric parameters of eddy current sensors.

[0085] In this application, in order to achieve accurate measurement of the thickness of metal components, an eddy current response analytical theoretical model is established to describe the relationship between the mutual inductance response of the excitation coil and the receiving coil in the swept frequency eddy current mode and the thickness and electromagnetic characteristics of the metal components.

[0086] Specifically, the eddy current response analytical theoretical model uses the electromagnetic properties of metal components, the geometric parameters of the sensor, and the measurement frequency as input to describe the change in the mutual inductance between the excitation coil and the receiving coil. The mathematical expression of the eddy current response analytical theoretical model is:

[0087]

[0088] Where:

[0089]

[0090] Wherein, M(ω) is the mutual inductance of the eddy current response at the angular frequency ω; K is the signal amplitude coefficient of the sensor, where N is the number of coil turns and μ0 is the magnetic permeability of vacuum; P(α) is a function of the geometric parameters of the coil, where J1(t) is a first-order Bessel function and t is an integral variable; α is an integral variable representing the wave number; φ(α) is a function related to the electromagnetic properties and thickness of the metal component; α1 is a complex wave number and j is an imaginary unit; d is the thickness of the metal component.

[0091] In this model, the electromagnetic properties of metal components are characterized by the conductivity σ. The conductivity directly affects the intensity and distribution of eddy currents and is an important parameter for thickness measurement.

[0092] In addition, the design parameters of the eddy current sensor directly affect the mutual inductance response of excitation and reception. The following geometric parameters need to be set in the analytical model: the inner diameter r1 and outer diameter r2 of the coil: determine the size and coverage of the coil; the coil height h: affects the distribution of the magnetic field and the depth effect of the eddy current; the coil spacing g: adjusts the relative position of the two sets of receiving coils and affects the mutual inductance response of the lift-off distance.

[0093] In one embodiment, the metal material is an aluminum plate, and the conductivity is set to 3.8×10 7 S / m, the inner diameter and outer diameter of the coil in the sensor are set to 3mm and 7mm respectively, the height of the coil is 1mm, the spacing of the coil is 1mm, and the number of turns of the coil is 100.

[0094] In addition, the model also needs to consider the lifting distance of the two pairs of excitation-receiving coil units. Different lifting distances can realize eddy current response detection at different depths of metal components, thereby improving the measurement sensitivity and anti-interference ability. This application does not elaborate on this.

[0095] By setting the above electromagnetic parameters and geometric parameters, the analytical theoretical model can accurately characterize the electromagnetic response relationship between the eddy current sensor and the metal component, providing a reliable theoretical basis for subsequent thickness inversion calculation.

[0096] S5, the frequency of the crossover point f c The mutual inductance value M0 is input into the eddy current response analytical theoretical model, the thickness measurement problem of metal components is transformed into a least squares optimization problem, and the improved Newton iterative algorithm is used to solve it.

[0097] In the embodiment of the present application, firstly, the frequency f of the intersection of the two differential mutual inductance response curves isc And the mutual inductance value M0 is input into the eddy current response analytical theoretical model, combined with the model expression M(ω c ,d), optimize and solve the thickness d.

[0098] It can be understood that the problem of measuring thickness is essentially to find the theoretical calculated value M(ω c ,d) is the thickness d when it is closest to the actual measured value M0. To this end, this application transforms the thickness measurement problem of metal components into a least squares optimization problem, and the objective function F(d) is defined as:

[0099]

[0100] In the formula, M(ω c , d) is the crossover angular frequency ω calculated based on the eddy current response analytical theoretical model c Below, the differential mutual inductance value corresponding to thickness d.

[0101] In order to use the Newton iterative algorithm to solve the thickness d, it is necessary to first calculate the Jacobian matrix J of the analytical model: d To achieve the optimal solution, the present embodiment uses the difference quotient method to calculate the Jacobian matrix J of the Newton iterative algorithm. d , the expression is:

[0102]

[0103] Wherein, Δd is the thickness step. The difference quotient method obtains the approximate value of the Jacobian matrix by calculating the difference in mutual inductance values ​​at adjacent thickness points. The method is simple to calculate and can meet the real-time requirements of the present invention in the thickness inversion process.

[0104] Therefore, according to the principle of Newton's iterative algorithm, the update formula of the thickness value d is:

[0105]

[0106] Where, d ′ is the thickness value of the updated metal component. is the inverse of the Jacobian matrix, which is used to correct the thickness value.

[0107] It should be noted that the updating process of the thickness value d is an iterative process that gradually approaches the true thickness. It requires repeated Jacobian matrix calculation and thickness value update until one of the following convergence conditions is met: the difference between the results of two adjacent iterations is less than the preset threshold or the maximum number of iterations is reached.

[0108] In one possible embodiment, when the difference between two adjacent thickness inversion results is less than 1×10 -5 mm, or the iteration ends when the maximum number of iterations, 100, is reached.

[0109] When the convergence condition is met, the output thickness value is the final thickness measurement result of the metal component.

[0110] It can be understood that the final output of the Newton iterative algorithm is the thickness value of the metal component obtained based on the least squares optimization problem. This result has high accuracy and robustness under the fluctuation of the lift-off distance, and can meet the needs of practical applications. Through the above steps, this application realizes the accurate inversion calculation of the thickness of the metal component, and the improvement of the Newton iterative algorithm further improves the efficiency and accuracy of the calculation.

[0111] In order to implement the above-mentioned embodiment, the present application also proposes a metal component thickness measurement device based on eddy current detection. Figure 5 The schematic diagram of the structure of a metal component thickness measurement device based on eddy current detection provided in an embodiment of the present application. Figure 5 As shown, the device comprises:

[0112] A sensor building module 100 is used to build an eddy current sensor consisting of a coaxial one excitation and two receiving coils, wherein the middle coil is the excitation coil, and the bottom and end coils are receiving coils, forming two pairs of excitation-receiving coil units with different lifting distances;

[0113] The detection module 200 is used to detect the metal component in the swept frequency eddy current mode using the constructed eddy current sensor to obtain the eddy current response signals M1(ω) and M2(ω) caused by the metal component;

[0114] The calculation module 300 is used to calculate the mean values ​​m1 and m2 of the two groups of eddy current response signals respectively, and to obtain two differential mutual inductance response curves by subtracting the original frequency sweep signal from the mean value, and to calculate the frequency f corresponding to the intersection of the two differential mutual inductance response curves. c and mutual inductance value M0;

[0115] The model building module 400 is used to build an eddy current response analytical theoretical model and set electromagnetic parameters of the metal component and geometric parameters of the eddy current sensor;

[0116] The solution module 500 is used to convert the frequency f of the crossover point c The mutual inductance value M0 is input into the eddy current response analytical theoretical model, the thickness measurement problem of the metal component is transformed into a least squares optimization problem, and the improved Newton iterative algorithm is used to solve it;

[0117] The loop module 600 is used to repeatedly execute the above input and solution process until the difference between two adjacent iteration results is less than a preset threshold or the maximum number of iterations is reached, and finally output the thickness measurement result of the metal component.

[0118] In order to implement the above embodiments, the present application also proposes an electronic device, comprising: a processor, and a memory communicatively connected to the processor; the memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the method provided by the above embodiments.

[0119] In order to implement the above embodiments, the present application also proposes a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement the methods provided by the above embodiments.

[0120] In order to implement the above embodiments, the present application also proposes a computer program product, including a computer program, which implements the methods provided by the above embodiments when executed by a processor.

[0121] The collection, storage, use, processing, transmission, provision and disclosure of user personal information involved in this application are in compliance with relevant laws and regulations and do not violate public order and good morals.

[0122] It should be noted that personal information from users should be collected for legitimate and reasonable purposes and should not be shared or sold outside of these legitimate uses. In addition, such collection / sharing should be carried out after receiving the user's informed consent, including but not limited to notifying the user to read the user agreement / user notice and sign the agreement / authorization including authorization of relevant user information before the user uses the function. In addition, any necessary steps should be taken to protect and safeguard access to such personal information data and ensure that others who have access to personal information data comply with its privacy policy and procedures.

[0123] The present application is expected to provide an implementation scheme for users to selectively block the use or access of personal information data. That is, the present disclosure is expected to provide hardware and / or software to prevent or block access to such personal information data. Once the personal information data is no longer needed, the risk can be minimized by limiting data collection and deleting the data. In addition, when applicable, such personal information is de-identified to protect the privacy of the user.

[0124] In the description of the aforementioned embodiments, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0125] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0126] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0127] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute the instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purpose of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways if necessary, and then stored in a computer memory.

[0128] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0129] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0130] In addition, each functional unit in each embodiment of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0131] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present application.

[0132] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps recorded in this application can be executed in parallel, sequentially or in different orders, as long as the expected results of the technical solution of this application can be achieved, and this document is not limited here.

[0133] The above specific implementations do not constitute a limitation on the protection scope of this application. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of this application should be included in the protection scope of this application.

Claims

1. A method for measuring the thickness of a metal component based on eddy current detection, characterized in that: The following steps are involved: S1. Build an eddy current sensor consisting of a coaxial excitation coil and two receiving coils, wherein the middle coil is the excitation coil, and the bottom and end coils are receiving coils, forming two pairs of excitation-receiving coil units with different lifting distances; S2, using the constructed eddy current sensor to detect the metal component in a swept frequency eddy current mode, and obtaining eddy current response signals M1(ω) and M2(ω) caused by the metal component; S3, respectively calculate the mean values ​​m1 and m2 of the two groups of eddy current response signals, and obtain two differential mutual inductance response curves by subtracting the original frequency sweep signal from the mean value, and calculate the frequency f corresponding to the intersection of the two differential mutual inductance response curves c and mutual inductance value M0; S4, establishing an eddy current response analytical theoretical model, setting the electromagnetic parameters of the metal component and the geometric parameters of the eddy current sensor; S5, the frequency of the crossover point f c The mutual inductance value M0 is input into the eddy current response analytical theoretical model, the thickness measurement problem of the metal component is converted into a least squares optimization problem, and an improved Newton iterative algorithm is used to solve it; Step S5 is repeatedly performed until the difference between two adjacent iteration results is less than a preset threshold or the maximum number of iterations is reached, and finally the thickness measurement result of the metal component is output.

2. The method according to claim 1, characterized in that The eddy current sensor is designed as a coaxial one excitation two receiving coil structure, wherein: The three coils are the same size; The middle coil is the excitation coil, and the bottom coil and the end coil are the receiving coils, which is equivalent to constructing two pairs of mutual inductance eddy current sensors with different lifting distances. The lifting distance of the first pair of excitation-receiving coils is l0, and the lifting distance of the second pair of excitation-receiving coils is l0+g+g.

3. The method according to claim 2, characterized in that The mean values ​​m1 and m2 of the two groups of eddy current response signals are calculated respectively, and the original frequency sweep signal is subtracted from the mean value to obtain two differential mutual inductance response curves, and the frequency f corresponding to the intersection of the two differential mutual inductance response curves is calculated. c And mutual inductance value M0, including: Calculate the mean values ​​of the eddy current response signals M1(ω) and M2(ω), denoted as m1 and m2 respectively; Subtract the eddy current response signals M1(ω) and M2(ω) from the mean values ​​m1 and m2 respectively to obtain two differential mutual inductance response curves M1(ω)-m1 and M2(ω)-m2; Draw the differential mutual inductance response curves M1(ω)-m1 and M2(ω)-m2, obtain the intersection point where the mutual inductance values ​​of the two curves are equal, and calculate the frequency f corresponding to the intersection point of the two differential mutual inductance response curves c And mutual inductance value M0.

4. The method according to claim 3, characterized in that: In the established eddy current response analytical theoretical model, the electromagnetic parameters of the metal component include conductivity σ, and the geometric parameters of the eddy current sensor include: the inner diameter r1 and outer diameter r2 of the coil, the height h of the coil, and the coil spacing g.

5. The method according to claim 4, characterized in that The expression of the eddy current response analytical theoretical model is: Where: Wherein, M(ω) is the mutual inductance value of the eddy current response at the angular frequency ω; K is the signal amplitude coefficient of the sensor, where N is the number of coil turns and μ0 is the vacuum permeability; P(α) is a function of the coil geometric parameters, where J1(t) is a first-order Bessel function and t is an integral variable; α is an integral variable representing the wave number; φ(α) is a function related to the electromagnetic properties and thickness of the metal component; α1 is a complex wave number and j is an imaginary unit; d is the thickness of the metal component.

6. The method according to claim 5, characterized in that The frequency of the crossover point f c The mutual inductance value M0 is input into the eddy current response analytical theoretical model, the thickness measurement problem of the metal component is converted into a least squares optimization problem, and the improved Newton iterative algorithm is used to solve it, including: The frequency f of the intersection of the two differential mutual inductance response curves c and the mutual inductance value M0 are input into the eddy current response analytical theoretical model; The thickness measurement problem of the metal component is transformed into a least squares problem, and the objective function F(d) is defined as: In the formula, M(ω c , d) is the crossover angular frequency ω calculated based on the eddy current response analytical theoretical model c Below, the differential mutual inductance value corresponding to thickness d; Calculate the Jacobian matrix J of Newton's iterative algorithm using the difference quotient method d , the expression is: Where Δd is the thickness step; The thickness value d is updated according to the following iterative formula: Where, d ′ is the thickness value of the metal component after updating, is the inverse of the Jacobian matrix, which is used to correct the thickness value.

7. A metal component thickness measuring device based on eddy current detection, characterized in that: include: A sensor building module is used to build an eddy current sensor consisting of a coaxial one excitation and two receiving coils, wherein the middle coil is the excitation coil, and the bottom and end coils are receiving coils, forming two pairs of excitation-receiving coil units with different lifting distances; A detection module, used to detect the metal component in a swept frequency eddy current mode using the constructed eddy current sensor, and obtain eddy current response signals M1(ω) and M2(ω) caused by the metal component; The calculation module is used to calculate the mean values ​​m1 and m2 of the two groups of eddy current response signals respectively, and to obtain two differential mutual inductance response curves by subtracting the original frequency sweep signal from the mean value, and to calculate the frequency f corresponding to the intersection of the two differential mutual inductance response curves. c and mutual inductance value M0; A model building module, used to build an eddy current response analytical theoretical model, set the electromagnetic parameters of the metal component and the geometric parameters of the eddy current sensor; The solver module is used to convert the frequency f of the crossover point c The mutual inductance value M0 is input into the eddy current response analytical theoretical model, the thickness measurement problem of the metal component is converted into a least squares optimization problem, and an improved Newton iterative algorithm is used to solve it; The loop module is used to repeatedly execute the above input and solution process until the difference between two adjacent iteration results is less than a preset threshold or the maximum number of iterations is reached, and finally output the thickness measurement result of the metal component.

8. An electronic device, characterized in that: include: A processor, and a memory communicatively connected to the processor; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory to implement the method according to any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, which are used to implement the method according to any one of claims 1 to 6 when executed by a processor.

10. A computer program product, characterized in that The invention comprises a computer program, which implements the method according to any one of claims 1 to 6 when being executed by a processor.

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