A device and method for acoustic vibration nondestructive detection of internal defects of magnetic tiles

Abstract

The present invention discloses a device and method for acoustic vibration nondestructive detection of internal defects of magnetic tiles, which relates to the field of internal defect detection of magnetic tiles, including a base, the upper surface of which is provided with a rotating platform, a vibration touch device and a signal acquisition and processing device; a rotating platform is provided with a rotating fence; a supporting assembly for supporting the inspected magnetic tile is provided on the outer side of the rotating fence; a vibration touch device is used to output a vibration signal to the inspected magnetic tile located in the supporting assembly; a signal acquisition and processing device is used to collect the acoustic vibration signal of the inspected magnetic tile, and perform nondestructive detection on the internal defects of the inspected magnetic tile based on the acoustic vibration signal. The present invention can be arranged in the production line of magnetic tiles, and quickly perform nondestructive detection on the internal defects of magnetic tiles.

Description

Technical Field

[0001] The invention relates to the field of magnetic tile internal defect detection, and in particular to a device and method for acoustic vibration nondestructive detection of magnetic tile internal defects. Background Art

[0002] Magnetic tiles are a type of tile-shaped magnet products, usually made of magnetic materials such as ferrite and neodymium iron boron, and are key components for generating magnetic fields in permanent magnet motors. However, the complex manufacturing process of magnetic tiles makes it inevitable that internal defects of the structure may occur during the production process. Compared with qualified magnetic tiles, internal defects will seriously reduce the magnetic properties and mechanical properties of magnetic tiles, thereby greatly affecting the service life and operating efficiency of permanent magnet motors. Therefore, detecting and eliminating magnetic tiles with internal defects is the primary task to ensure the quality of magnetic tile products, and the existing methods for detecting internal defects of magnetic tiles mostly rely on manually knocking magnetic tiles on metal blocks to stimulate sound, and identify the crispness and turbidity of this sound through the long-term listening experience of human ears to determine whether there are internal defects. This manual detection method requires professional inspectors who have received long-term training to complete, and the detection standards, test results, and detection speed are easily affected by human factors such as individual experience differences, hearing differences, attention differences, and fatigue differences. Excessive knocking force can easily cause secondary damage to the magnetic tiles, causing new defects or aggravating existing defects.

[0003] In addition, some existing solutions for defect detection of magnetic tiles through other technical means need to be carried out in the laboratory. The detection process is separated from the production line environment, which is not conducive to assembly line operation and lacks practical application feasibility. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides a device and method for acoustic vibration nondestructive detection of internal defects of magnetic tiles, which solves the problem that the existing magnetic tile defect detection scheme is separated from the production line environment and cannot directly perform magnetic tile defect detection on the production line.

[0005] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0006] Provided is a device for acoustic vibration nondestructive testing of internal defects of magnetic tiles, comprising a base, the upper surface of which is provided with a rotating platform, a vibration touch device and a signal acquisition and processing device; a rotating wall is provided on the rotating platform; a supporting assembly for supporting the inspected magnetic tile is provided on the outer side of the rotating wall;

[0007] A vibration touch device, used to output a vibration signal to the magnetic tile under test in the supporting assembly;

[0008] The signal acquisition and processing equipment is used to collect the acoustic vibration signal of the inspected magnetic tile and perform non-destructive detection of the internal defects of the inspected magnetic tile based on the acoustic vibration signal.

[0009] The beneficial effect of the present invention is that the device can be arranged in a production line of magnetic tiles and can quickly perform non-destructive detection on internal defects of the magnetic tiles.

[0010] Furthermore, the vibration touch device includes a lifter, a resonance speaker, a first connector and a vibration transmission cone; wherein:

[0011] The elevator is arranged on the upper surface of the base; the resonance horn is fixed on the lifting table of the elevator through the first connector; and the vibration transmission cone is arranged on the top of the resonance horn.

[0012] The beneficial effects of adopting the above-mentioned further scheme are as follows: the resonant horn can output stable energy, achieve extremely high conversion efficiency of mechanical wave to sound wave energy, and can enhance the intensity of the acoustic vibration signal generated during collision within the maximum safety range; the hard contact between the vibration touch device and the magnetic tile to be tested can be avoided by means of a lift before data collection, and the vibration transmission cone can be vibrated before the magnetic tile to be tested contacts the vibration transmission cone, thereby ensuring that the acoustic vibration signal of the magnetic tile to be tested has lower noise; and the setting method of the vibration touch device does not affect the flow of the magnetic tile to be tested, which is convenient for assembly line operation.

[0013] Furthermore, the signal acquisition and processing device includes a microphone stand, a signal acquisition microphone, a second connector and a host computer; wherein:

[0014] The microphone bracket is fixed on the upper surface of the base through the second connector; the signal acquisition microphone is arranged on the microphone bracket and is used to collect the acoustic vibration signal of the magnetic tile under inspection; the signal acquisition microphone is connected to the upper computer for communication.

[0015] The beneficial effect of adopting the above further scheme is that the signal acquisition and processing equipment collects the acoustic vibration signal of the magnetic tile under inspection through the signal acquisition microphone, which can realize close-range and contactless collection, facilitating subsequent non-destructive testing.

[0016] Furthermore, a magnetic tile internal defect recognition model is deployed in the upper computer, and the magnetic tile internal defect recognition model includes a fast Fourier transform layer, a patch embedding layer, an initial convolution layer, N dense convolution stacking layers, a global average pooling layer, a HIFA feature fusion layer, a fully connected layer and a softmax classification layer connected in sequence; another input of the HIFA feature fusion layer is the output of the last dense convolution stacking layer; the output of the softmax classification layer is the output of the magnetic tile internal defect recognition model, and the output includes no internal defects and the presence of internal defects; the input of the fast Fourier transform layer is the input of the magnetic tile internal defect recognition model.

[0017] Furthermore, each dense convolution stack layer includes a Depthwise convolution unit, a first ReLU activation unit, a first batch of normalization units, an element addition unit, a Pointwise convolution unit, a second ReLU activation unit, and a second batch of normalization units connected in sequence; another input of the element addition unit is the input of the dense convolution stack layer where the element addition unit is located; the calculation expression of a single dense convolution stack layer is:

[0018]

[0019]

[0020] in Represents the input of a single dense convolutional stack layer; Represents Depthwise convolution; represents ReLU activation; represents batch normalization; It means element-by-element addition; is the output of the element addition unit; Represents Pointwise convolution; Represents the output of a single dense convolutional stack;

[0021] The calculation expression of the HIFA feature fusion layer is:

[0022]

[0023] in is the output of the HIFA feature fusion layer; and All are weight matrices; is the output of the global average pooling layer; is the output of the last dense convolution stack layer;

[0024] The calculation expression of the fully connected layer is:

[0025]

[0026] in is the output of the fully connected layer; is the weight matrix; is the bias term;

[0027] The calculation expression of the softmax classification layer is:

[0028]

[0029] in Represents the output of the fully connected layer Corresponding to category kThe probability of the category with the highest probability is the detection result of the signal acquisition and processing equipment; e is a natural constant; C is the total number of categories; Indicates category .

[0030] The beneficial effects of adopting the above further scheme are: the magnetic tile internal defect recognition model can accurately perform non-destructive detection of the internal defects of the magnetic tile being inspected, and the magnetic tile internal defect recognition model can run in a host computer of a Linux embedded system, iOS system or Windows system, which is convenient for industrial implementation.

[0031] Furthermore, a first pushing device and a second pushing device are arranged above the rotating platform; the first pushing device and the second pushing device have different orientations and are used to push the magnetic tile to be tested in the supporting assembly to different positions according to the detection result of the signal acquisition and processing device;

[0032] The first pushing device and the second pushing device both include a pushing plate, a piston rod and a pushing pump; the pushing pump is controlled by the detection result of the signal acquisition and processing device;

[0033] In the same pushing device, the push plate is arranged at the movable end of the piston rod, and the movable end of the piston rod is driven by the pushing pump.

[0034] Furthermore, the rotating platform is hollow, and the upper surface of the base supports a placement platform located above the rotating wall through columns; the columns are located in the hollow part of the rotating platform; the placement platform is used to fix the first pushing device and the second pushing device.

[0035] The beneficial effect of adopting the above further scheme is that the two pushing devices can correspond to two kinds of test results, so as to push the tested magnetic tiles with different test results to different outlets or production lines, realize the automatic classification of the tested magnetic tiles, and facilitate the subsequent processing of the magnetic tile products. In addition, the rotating platform is arranged above the rotating platform and the rotating fence, so that the device has a compact structure and a small footprint, and is easy to deploy in the magnetic tile production line.

[0036] A method for acoustic vibration nondestructive detection of internal defects of magnetic tiles based on an acoustic vibration nondestructive detection device for internal defects of magnetic tiles is provided, which comprises the following steps:

[0037] S1. Place the magnetic tile to be inspected in the supporting assembly;

[0038] S2, rotating the supporting assembly supporting the magnetic tile to be inspected to the top of the vibration touch device through the rotating platform;

[0039] S3, outputting a vibration signal to the magnetic tile under test in the supporting assembly through a vibration touch device;

[0040] S4. Acquire the acoustic vibration signal of the inspected magnetic tile through the signal acquisition and processing equipment, and perform non-destructive detection on the internal defects of the inspected magnetic tile based on the acoustic vibration signal.

[0041] Furthermore, the specific method of outputting a vibration signal to the magnetic tile under test in the supporting assembly through the vibration touch device is as follows:

[0042] The resonant horn is made to continuously output vibration at a frequency of 95 Hz and drive the vibration-transmitting cone to vibrate synchronously; the vibration-transmitting cone is made to contact with the curved lower surface of the magnetic tile to be tested for 1 second through a lift, so that the magnetic tile to be tested generates an acoustic vibration signal due to the contact.

[0043] The beneficial effect of the present invention is that the method can quickly perform non-destructive detection on internal defects of magnetic tiles.

[0044] Furthermore, after step S4, the method further includes the following steps:

[0045] S5. If the detection result of the signal acquisition and processing equipment is that there is no internal defect, the supporting assembly supporting the inspected magnetic tile is rotated to above the qualified product assembly line by the rotating platform, and the inspected magnetic tile is pushed to the qualified product assembly line by the first pushing device;

[0046] If the detection result of the signal acquisition and processing equipment is that there is an internal defect, the supporting assembly supporting the inspected magnetic tile is rotated to above the waste product outlet through the rotating platform, and the inspected magnetic tile is pushed to the waste product outlet through the second pushing device.

[0047] The beneficial effect of adopting the above further scheme is that the inspected magnetic tiles can be pushed to different outlets or assembly lines according to the detection results, thereby realizing automatic classification of the inspected magnetic tiles and facilitating subsequent processing of the magnetic tile products. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is the overall structural diagram of the device;

[0049] Figure 2 This is a schematic diagram of the explosion structure of the device;

[0050] Figure 3 is a top view of the device;

[0051] Figure 4 This is a structural diagram of the magnetic tile internal defect recognition model;

[0052] Figure 5 Time domain diagram of acoustic vibration signal of qualified magnetic tile;

[0053] Figure 6 This is the time domain diagram of the acoustic vibration signal of the internal defective magnetic tile;

[0054] Figure 7 This is the frequency domain diagram of the acoustic vibration signal of the qualified magnetic tile;

[0055] Figure 8 This is the frequency domain diagram of the acoustic vibration signal of the internal defective magnetic tile;

[0056] Fig. 9 This is the convergence curve of the loss function of the magnetic tile internal defect recognition model and the ConvMixer original model during training;

[0057] Fig.10 It is the convergence curve diagram of the verification function of the magnetic tile internal defect recognition model and the ConvMixer original model in the verification;

[0058] Fig.11 This is the accuracy convergence curve of the magnetic tile internal defect recognition model and the ConvMixer original model in the test;

[0059] Fig.12 This is the confusion matrix obtained by the magnetic tile internal defect recognition model in the test;

[0060] Fig.13 This is a comparison chart of the indicators of the magnetic tile internal defect recognition model and the ConvMixer original model in the test.

[0061] Among them: 1. Base; 2. Rotating platform; 3. Rotating fence; 4. Placement platform; 5. Vibration touch device; 6. Signal acquisition and processing equipment; 7. First pushing device; 8. Magnetic tile to be tested; 9. Second pushing device; 11. Support legs; 31. Supporting assembly; 51. Lift; 52. Resonance speaker; 53. First connector; 54. Vibration cone; 61. Microphone holder; 62. Signal acquisition microphone; 63. Second connector; 71. Push plate; 72. Piston rod; 73. Push pump. DETAILED DESCRIPTION

[0062] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0063] like Figure 1 , Figure 2 and Figure 3As shown, the device for acoustic vibration nondestructive testing of internal defects of magnetic tiles comprises a base 1, the upper surface of which is provided with a rotating platform 2, a vibration touch device 5 and a signal acquisition and processing device 6; a rotating wall 3 is provided on the rotating platform 2; and a supporting component 31 for supporting the magnetic tile 8 to be inspected is provided on the outer side of the rotating wall 3;

[0064] The vibration touch device 5 is used to output a vibration signal to the magnetic tile 8 under test in the supporting assembly 31;

[0065] The signal acquisition and processing device 6 is used to acquire the acoustic vibration signal of the inspected magnetic tile 8, and perform non-destructive detection of internal defects of the inspected magnetic tile 8 based on the acoustic vibration signal.

[0066] The vibration touch device 5 includes a lift 51, a resonance speaker 52, a first connector 53 and a vibration transmission cone 54; wherein:

[0067] The elevator 51 is arranged on the upper surface of the base 1; the resonance speaker 52 is fixed on the lifting table of the elevator 51 through the first connector 53, and outputs a vibration signal with a frequency of 95 Hz; the vibration transmission cone 54 is arranged on the top of the resonance speaker 52. The vibration transmission cone 54 can be set as a cone-like structure with a smooth spherical top.

[0068] In the specific implementation process, a support leg 11 is fixed to the lower surface of the base 1, and a motor is fixed to the base 1. The motor drives the rotating platform 2 to rotate through gears, and the rotating platform 2 synchronously drives the rotating fence 3 to rotate, so that the supporting assembly 31 can be rotated to different orientations. This setting method allows the rotating platform 2 to rotate 360° relative to the base 1. In addition, the rotating platform 2 can also be directly fixed to the rotating shaft of the motor, and the rotating platform 2 can be directly driven to rotate by the rotation of the motor. Since the main function of the rotating platform 2 is to drive the supporting assembly 31 to rotate, there are many settings that can achieve the above functions, and other feasible solutions will not be repeated here.

[0069] The supporting assembly 31 includes a threaded handle and a circular ring. One end of the threaded handle is detachably fixed to the outside of the rotating enclosure 3, and the other end is fixed to the circular ring. The circular ring is arranged in such a way that the curved lower surface of the magnetic tile 8 to be inspected can be located below the supporting assembly 31, which is convenient for subsequent inspection. In addition, other supporting assemblies 31 of different shapes can be used in the present device as long as the curved lower surface of the magnetic tile 8 to be inspected is exposed to the outside. Other feasible solutions will not be described here.

[0070] The signal acquisition and processing device 6 includes a microphone stand 61, a signal acquisition microphone 62, a second connector 63 and a host computer; wherein:

[0071] The microphone holder 61 is fixed to the upper surface of the base 1 through the second connector 63; the signal acquisition microphone 62 is arranged on the microphone holder 61, and is used to collect the acoustic vibration signal of the magnetic tile 8 under inspection; the signal acquisition microphone 62 is connected to the upper computer for communication.

[0072] In the specific implementation process, the signal acquisition microphone 62 has a built-in digital-to-analog conversion and signal conditioning circuit to realize the preprocessing of the collected signal. The sampling bit number of the acoustic vibration signal collected by the signal acquisition microphone 62 is 32 bits, the collection frequency is 44.1kHz, the file type is txt, and the duration is 1s (corresponding to the contact time between the vibration transmission cone 54 and the magnetic tile 8 under test).

[0073] The first connector 53 and the second connector 63 can both adopt L-shaped connecting pieces. When the first connector 53 adopts L-shaped connecting pieces, it can be fixed to the side of the resonance speaker 52 and the upper surface of the elevator 51 by screws. When the second connector 63 adopts L-shaped connecting pieces, it can be fixed to the upper surface of the base 1 and the side of the microphone bracket 61 by screws. The elevator 51 can adopt an electric lifting method, and its driving motor is connected to the upper computer for communication.

[0074] The host computer has deployed a magnetic tile internal defect recognition model, such as Figure 4 As shown, the magnetic tile internal defect recognition model includes a fast Fourier transform layer, a patch embedding layer, an initial convolution layer, N dense convolution stacking layers, a global average pooling layer, a HIFA feature fusion layer, a fully connected layer and a softmax classification layer connected in sequence; the other input of the HIFA feature fusion layer is the output of the last dense convolution stacking layer; the output of the softmax classification layer is the output of the magnetic tile internal defect recognition model, and the output includes no internal defects and the presence of internal defects; the input of the fast Fourier transform layer is the input of the magnetic tile internal defect recognition model.

[0075] Each dense convolution stack layer includes a Depthwise convolution unit, a first ReLU activation unit, a first batch of normalization units, an element addition unit, a Pointwise convolution unit, a second ReLU activation unit, and a second batch of normalization units connected in sequence; the other input of the element addition unit is the input of the dense convolution stack layer where the element addition unit is located; the calculation expression of a single dense convolution stack layer is:

[0076]

[0077]

[0078] in Represents the input of a single dense convolutional stack layer; Represents Depthwise convolution; represents ReLU activation; represents batch normalization; It means element-by-element addition; is the output of the element addition unit; Represents Pointwise convolution; Represents the output of a single dense convolutional stack;

[0079] The calculation expression of the global average pooling layer is:

[0080]

[0081] in The output of the last dense convolution stack layer No. i Global average pooling result of channels; and for The height and width of for middle The value at the position;

[0082] In this embodiment, the global average pooling layer will The size of is resized from (1, 512, 32, 32) to (1,512).

[0083] The calculation expression of the HIFA feature fusion layer is:

[0084]

[0085] in is the output of the HIFA feature fusion layer; and All are weight matrices; is the output of the global average pooling layer, ; is the output of the last dense convolution stack layer;

[0086] The calculation expression of the fully connected layer is:

[0087]

[0088] in is the output of the fully connected layer; is the weight matrix; is the bias term;

[0089] The calculation expression of the softmax classification layer is:

[0090]

[0091] in Represents the output of the fully connected layer Corresponding to category k The probability of the category with the highest probability is the detection result of the signal acquisition and processing device 6; e is a natural constant; C is the total number of categories; Indicates category .

[0092] A first pushing device 7 and a second pushing device 9 are arranged above the rotating platform 2; the first pushing device 7 and the second pushing device 9 have different orientations and are used to push the magnetic tile 8 to be tested in the supporting assembly 31 to different positions according to the detection result of the signal acquisition and processing device 6;

[0093] The first pushing device 7 and the second pushing device 9 both include a pushing plate 71, a piston rod 72 and a pushing pump 73; the pushing pump 73 is controlled by the detection result of the signal acquisition and processing device 6;

[0094] In the same pushing device, the pushing plate 71 is arranged at the movable end of the piston rod 72 , and the movable end of the piston rod 72 is driven by the pushing pump 73 .

[0095] In the specific implementation process, the push pump 73 can be an air pump or a hydraulic pump to achieve the pushing function in a pneumatic or hydraulic manner. In order to achieve the linkage of the entire device, the push pump 73 is connected to the host computer for communication.

[0096] The rotating platform 2 is hollow, and the upper surface of the base 1 supports a placement platform 4 located above the rotating fence 3 through a column; the column is located in the hollow part of the rotating platform 2; the placement platform 4 is used to fix the first pushing device 7 and the second pushing device 9. The power lines and signal lines of the first pushing device 7 and the second pushing device 9 can be laid through the inside of the column.

[0097] The method for acoustic vibration nondestructive detection of internal defects of magnetic tiles based on the device for acoustic vibration nondestructive detection of internal defects of magnetic tiles comprises the following steps:

[0098] S1, placing the magnetic tile 8 to be inspected in the supporting assembly 31;

[0099] S2, rotating the supporting assembly 31 supporting the magnetic tile 8 to be inspected to the position directly above the vibration touch device 5 by means of the rotating platform 2;

[0100] S3, outputting a vibration signal to the magnetic tile 8 to be inspected in the supporting assembly 31 through the vibration touch device 5; after outputting the vibration signal, the vibration touch device 5 is separated from the contact with the magnetic tile 8 to be inspected in the supporting assembly 31;

[0101] S4, collecting the acoustic vibration signal of the inspected magnetic tile 8 through the signal acquisition and processing device 6, and performing non-destructive detection on the internal defects of the inspected magnetic tile 8 based on the acoustic vibration signal;

[0102] S5. If the detection result of the signal acquisition and processing device 6 is that there is no internal defect, the supporting assembly 31 supporting the magnetic tile 8 to be inspected is rotated to above the qualified product assembly line by the rotating platform 2, and the magnetic tile 8 to be inspected is pushed to the qualified product assembly line by the first pushing device 7;

[0103] If the detection result of the signal acquisition and processing device 6 is that there is an internal defect, the supporting assembly 31 supporting the inspected magnetic tile 8 is rotated to above the waste product outlet through the rotating platform 2, and the inspected magnetic tile 8 is pushed to the waste product outlet through the second pushing device 9.

[0104] The specific method of outputting a vibration signal to the magnetic tile 8 under test in the supporting assembly 31 through the vibration touch device 5 is as follows:

[0105] The resonance speaker 52 is made to continuously output vibration at a frequency of 95 Hz and drive the vibration-transmitting cone 54 to vibrate synchronously; the vibration-transmitting cone 54 is made to contact the curved lower surface of the magnetic tile 8 to be tested for 1 second through the elevator 51, so that the magnetic tile 8 to be tested generates an acoustic vibration signal due to the contact.

[0106] In the specific implementation process, with the two-dimensional coordinate system as the reference, the magnetic tile 8 to be tested can be placed in the supporting component 31 at the 0° direction, which corresponds to the delivery window of the magnetic tile 8 to be tested; non-destructive testing can be performed at the 90° direction (corresponding to the position of the vibration touch device 5 and the signal acquisition and processing device 6); the pushing direction of the first pushing device 7 is located in the 180° direction, which corresponds to the qualified product assembly line; the second pushing device 9 is located in the 270° direction, which corresponds to the waste product outlet. This setting method can produce a maximized interval, which is convenient for arranging the delivery window of the magnetic tile 8 to be tested, related testing equipment, qualified product assembly lines and waste product outlets, so as to facilitate the application of this device in assembly line production. Under this setting method, the supporting component 31 can also be set to 4 correspondingly, so that each time the supporting component 31 is rotated, a new magnetic tile 8 to be tested can be supported, and the next magnetic tile 8 to be tested can be non-destructively tested.

[0107] It should be noted that the above-mentioned relative direction is only one feasible method. The setting relationship of other relative directions can also be used as the specific setting method of the present invention as long as it does not affect the delivery, detection, and classification push. Due to the large number of optional setting methods, they will not be repeated here.

[0108] In one embodiment of the present invention, the time domain diagram and frequency domain diagram of the acoustic vibration signal of the qualified magnetic tile and the internal defective magnetic tile are respectively as follows: Figure 5 , Figure 6 , Figure 7 and Figure 8As shown, it can be seen that the presence or absence of internal defects will cause differences in the acoustic vibration signal of the magnetic tile in both the time domain and the frequency domain. The magnetic tile internal defect recognition model can be trained before use, and the training samples are mixed acoustic vibration signal samples of qualified magnetic tiles and acoustic vibration signal samples of magnetic tiles with internal defects. The performance comparison of the magnetic tile internal defect recognition model and the original ConvMixer model in the training set and the validation set is shown in the figure. Fig. 9 and Fig.10 As shown in the figure, the training loss of the magnetic tile internal defect recognition model is 0.0075, and the validation loss is 0.0107. The performance comparison between the magnetic tile internal defect recognition model and the original ConvMixer model in the test set is as follows: Fig.11 As shown in Figure 1, the accuracy of the magnetic tile internal defect recognition model is as high as 0.9978. The confusion matrix of the magnetic tile internal defect recognition model in the test set is as follows: Fig.12 As shown in Table 1, it can be seen that the test accuracy of the magnetic tile internal defect recognition model in the test set is as high as 99.72%. Fig.13 The figure shows the recognition results of the same 1086 samples in the test of the internal defect recognition model of magnetic tiles and the original ConvMixer model. The test accuracy of the internal defect recognition model of magnetic tiles reached 99.72%, the recall rate reached 0.9949, the F1 score reached 0.9974, and the loss rate was only 0.0181. This ensures that the recognition rate of the internal defect recognition model of magnetic tiles for qualified magnetic tiles is not less than 95%.

[0109] Table 1

[0110]

[0111] In summary, the present invention can quickly perform nondestructive detection on the internal defects of magnetic tiles, and can also push the inspected magnetic tiles to different outlets or assembly lines according to the detection results, thereby realizing automatic classification of the inspected magnetic tiles and facilitating subsequent processing of the magnetic tile products.

Claims

1. A device for acoustic vibration nondestructive testing of internal defects of magnetic tiles, characterized in that: The device comprises a base (1), wherein the upper surface of the base (1) is provided with a rotating platform (2), a vibration touch device (5) and a signal acquisition and processing device (6); a rotating wall (3) is provided on the rotating platform (2); and a supporting component (31) for supporting a magnetic tile (8) to be inspected is provided on the outer side of the rotating wall (3); A vibration touch device (5) for outputting a vibration signal to the magnetic tile (8) to be tested located in the supporting assembly (31); A signal acquisition and processing device (6) is used to acquire an acoustic vibration signal of the magnetic tile (8) to be inspected, and to perform non-destructive detection of internal defects of the magnetic tile (8) to be inspected based on the acoustic vibration signal. The vibration touch device (5) comprises a lift (51), a resonance speaker (52), a first connector (53) and a vibration transmission cone (54); wherein: The elevator (51) is arranged on the upper surface of the base (1); the resonance speaker (52) is fixed on the lifting table of the elevator (51) via a first connector (53); and the vibration transmission cone (54) is arranged on the top of the resonance speaker (52); A first pushing device (7) and a second pushing device (9) are arranged above the rotating platform (2); the first pushing device (7) and the second pushing device (9) are oriented in different directions and are used to push the magnetic tile (8) to be tested, which is located in the supporting assembly (31), to different positions according to the detection result of the signal acquisition and processing device (6); The first pushing device (7) and the second pushing device (9) both comprise a pushing plate (71), a piston rod (72) and a pushing pump (73); the pushing pump (73) is controlled by the detection result of the signal acquisition and processing device (6); In the same pushing device, the push plate (71) is arranged at the movable end of the piston rod (72), and the movable end of the piston rod (72) is driven by the pushing pump (73).

2. The device for acoustic vibration nondestructive testing of internal defects of magnetic tiles according to claim 1 is characterized in that: The signal acquisition and processing device (6) comprises a microphone stand (61), a signal acquisition microphone (62), a second connector (63) and a host computer; wherein: The microphone bracket (61) is fixed to the upper surface of the base (1) via a second connector (63); the signal collection microphone (62) is arranged on the microphone bracket (61) and is used to collect acoustic vibration signals of the magnetic tile (8) to be tested; the signal collection microphone (62) is communicatively connected to the host computer.

3. The device for acoustic vibration nondestructive testing of internal defects of magnetic tiles according to claim 2 is characterized in that: A magnetic tile internal defect recognition model is deployed in the host computer, which includes a fast Fourier transform layer, a patch embedding layer, an initial convolution layer, N dense convolution stacking layers, a global average pooling layer, a HIFA feature fusion layer, a fully connected layer and a softmax classification layer connected in sequence; the other input of the HIFA feature fusion layer is the output of the last dense convolution stacking layer; the output of the softmax classification layer is the output of the magnetic tile internal defect recognition model, and the output includes no internal defects and the presence of internal defects; the input of the fast Fourier transform layer is the input of the magnetic tile internal defect recognition model.

4. The device for acoustic vibration nondestructive testing of internal defects of magnetic tiles according to claim 3 is characterized in that: Each dense convolution stack layer includes a Depthwise convolution unit, a first ReLU activation unit, a first batch of normalization units, an element addition unit, a Pointwise convolution unit, a second ReLU activation unit, and a second batch of normalization units connected in sequence; the other input of the element addition unit is the input of the dense convolution stack layer where the element addition unit is located; the calculation expression of a single dense convolution stack layer is: in Represents the input of a single dense convolutional stack layer; Represents Depthwise convolution; represents ReLU activation; represents batch normalization; It means element-by-element addition; is the output of the element addition unit; Represents Pointwise convolution; Represents the output of a single dense convolutional stack; The calculation expression of the HIFA feature fusion layer is: in is the output of the HIFA feature fusion layer; and All are weight matrices; is the output of the global average pooling layer; is the output of the last dense convolution stack layer; The calculation expression of the fully connected layer is: in is the output of the fully connected layer; is the weight matrix; is the bias term; The calculation expression of the softmax classification layer is: in Represents the output of the fully connected layer Corresponding to category k The probability of the category with the highest probability is the detection result of the signal acquisition and processing device (6); e is a natural constant; C is the total number of categories; Indicates category .

5. The device for acoustic vibration nondestructive testing of internal defects of magnetic tiles according to claim 1 is characterized in that: The rotating platform (2) is hollow, and the upper surface of the base (1) supports a placement platform (4) located above the rotating wall (3) through columns; the columns are located in the hollow part of the rotating platform (2); the placement platform (4) is used to fix the first pushing device (7) and the second pushing device (9).

6. A method for acoustic vibration nondestructive testing of magnetic tile internal defects based on the device for acoustic vibration nondestructive testing of magnetic tile internal defects according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1, placing the magnetic tile (8) to be inspected in a supporting assembly (31); S2, rotating the supporting assembly (31) supporting the magnetic tile (8) to be inspected to the position directly above the vibration touch device (5) by means of the rotating platform (2); S3, outputting a vibration signal to the magnetic tile (8) to be inspected located in the supporting assembly (31) through the vibration touch device (5); S4. Acquiring an acoustic vibration signal of the inspected magnetic tile (8) through a signal acquisition and processing device (6), and performing non-destructive detection of internal defects of the inspected magnetic tile (8) based on the acoustic vibration signal.

7. The method for acoustic vibration nondestructive testing of internal defects of magnetic tiles according to claim 6, characterized in that: The specific method of outputting a vibration signal to the magnetic tile (8) to be tested located in the supporting assembly (31) by means of the vibration touch device (5) is as follows: The resonant speaker (52) is made to continuously output vibration at a frequency of 95 Hz and drive the vibration transmission cone (54) to synchronously generate vibration; the vibration transmission cone (54) is made to contact the arc lower surface of the magnetic tile (8) to be tested for 1 second through the elevator (51), so that the magnetic tile (8) to be tested generates an acoustic vibration signal due to the contact.

8. The method for acoustic vibration nondestructive testing of internal defects of magnetic tiles according to claim 6, characterized in that: After step S4, the method further includes the following steps: S5. If the detection result of the signal acquisition and processing device (6) is that there is no internal defect, the supporting assembly (31) supporting the magnetic tile (8) to be inspected is rotated to above the qualified product assembly line by the rotating platform (2), and the magnetic tile (8) to be inspected is pushed to the qualified product assembly line by the first pushing device (7); If the detection result of the signal acquisition and processing device (6) is that there is an internal defect, the supporting assembly (31) supporting the magnetic tile (8) to be inspected is rotated to above the waste product outlet via the rotating platform (2), and the magnetic tile (8) to be inspected is pushed to the waste product outlet via the second pushing device (9).

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