Automobile motor core dual-view size detection method and system

Abstract

The application discloses a double-view angle size detection method and system for an automobile motor core, wherein the core workpiece is vertically placed, a plurality of outer ring width data are collected through a first visual camera on the side surface in cooperation with the rotation of the core workpiece, an outer ring elliptical model is established, and the outer ring center and the elliptical eccentricity are obtained; a top view image is collected through a second visual camera on the top, a plurality of independent arc segment profiles of an inner ring are extracted, the centers of the arc segments are fitted, and the deviation of the overall center of the inner ring and the concentricity is calculated; and the overall center of the inner ring and the concentricity deviation are used to double-verify the outer ring center and the elliptical eccentricity.

Description

Technical Field

[0001] This invention relates to visual inspection technology for iron core workpieces, and more specifically, to a dual-view dimension inspection method for automotive motor iron cores, and also to a dual-view dimension inspection system for automotive motor iron cores. Background Technology

[0002] Automotive motor cores are mostly ring-shaped structures, which are easily subjected to external pressure during processing, clamping, and transportation, causing the outer circle to change from a perfect circle to an ellipse, directly affecting the motor's assembly accuracy and operating performance. Traditional inspection methods are mostly single-viewpoint and single-measurement, which cannot characterize changes in the entire circumference and are difficult to accurately identify elliptical deformation. At the same time, single-vision inspection is easily affected by factors such as lighting, edge noise, and eccentricity of the core workpiece, and lacks a reliable internal feature verification mechanism.

[0003] The inner ring of a motor core is typically composed of multiple independent arc-shaped segments. When the outer circumference undergoes flattening deformation, the shape of each arc-shaped segment remains unchanged; only the center shifts, concentricity deteriorates, and circumferential distribution becomes uneven. Existing technologies do not fully utilize this internal characteristic to cross-validate the outer circumference inspection results, resulting in insufficient accuracy, stability, and reliability to meet the stringent requirements of online full inspection of high-end motor cores. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method and system for dual-view dimension detection of automotive motor cores.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for dual-view dimensional inspection of automotive motor cores includes the following steps:

[0007] The iron core workpiece is placed vertically, and multiple sets of outer ring width data are collected by the side first vision camera in conjunction with the rotation of the iron core workpiece. An outer ring elliptical model is established to obtain the eccentricity between the outer ring center and the ellipse.

[0008] The top view image is acquired by the second visual camera at the top, the contours of multiple independent arc segments of the inner ring are extracted, the center of each arc segment is fitted, and the overall center and concentricity deviation of the inner ring are calculated.

[0009] By utilizing the overall center and concentricity deviation of the inner ring, the eccentricity of the outer ring's center and ellipse is double-verified.

[0010] Furthermore, the outer ring elliptical model of the iron core workpiece is determined according to the rotation angle. The outer elliptical model of the iron core workpiece is constructed as follows:

[0011]

[0012] Where θ is the angle of rotation of the iron core workpiece, W(θ) is the width data collected by the rotation angle θ of the iron core workpiece, a is the major semi-axis, b is the minor semi-axis, and φ is the initial deflection angle of the major axis of the ellipse.

[0013] Furthermore, based on the major semi-axis a and minor semi-axis b in the outer ring elliptical model of the iron core workpiece, the eccentricity e of the outer ring of the iron core workpiece is obtained, and the eccentricity e is:

[0014]

[0015] When e=0, the outer ring of the iron core workpiece is a perfect circle. The larger the e is, the flatter the outer ring of the iron core workpiece is.

[0016] Furthermore, in the process of collecting data on the rotation of the iron core workpiece, four sets of width data are collected to form rotation angle and width data W(θi), i∈{1,2,3,…,n}, n≥4;

[0017] θ1=0°, θ2=α, θ3=2α, θ4=3α, and the range of α is 50°-80°.

[0018] Furthermore, in this invention, any three groups are selected from the n groups of data, and the combined data forms four groups of outer ring ellipse models, resulting in the values ​​of the major semi-axis a and minor semi-axis b of group C(i,3): (ai,bi);

[0019] Based on each group (ai, bi), obtain the mean and standard deviation of the major and minor semi-axis. The mean is:

[0020]

[0021] The standard deviation is:

[0022]

[0023] When the standard deviations of both the major and minor semi-axis are less than the threshold, the test data is considered valid. The eccentricity e of the outer ring of the core workpiece is obtained based on the mean of the major and minor semi-axis.

[0024] In a further embodiment of the present invention, the core workpiece includes an inner ring, which includes m independently distributed arc-shaped bodies, each arc-shaped body being fixedly connected to the inner circumference of the outer ring by connecting ribs; each arc-shaped body maintains a standard circular arc, and its center shifts when the outer ring is flattened.

[0025] Obtain the position Oj(Xj,Yj) of the center of each arc segment relative to the center of the outer ring ellipse model;

[0026] The overall center Oin(Xin,Yin) of the inner ring is:

[0027]

[0028] Where j∈{1,2,3,…,m}, j represents the index of the arc shape, and m represents the total number of arc shapes.

[0029] The present invention further obtains the concentricity deviation of the inner ring based on the center position Oj(Xj,Yj) of each arc segment. The deviation between the center of the outer circle and the overall center of the inner ring ;

[0030] for:

[0031]

[0032] for:

[0033]

[0034] when When the value is less than or equal to the threshold, the center positioning of the outer and inner rings is considered valid.

[0035] Furthermore, this invention performs correlation judgment based on the ellipticity of the outer ring and the concentricity of the inner ring to obtain a dual correlation coefficient T, achieving dual verification of the outer and inner rings; the correlation coefficient T is:

[0036]

[0037] in, For calibration coefficients, This is the correlation threshold;

[0038] When the correlation coefficient T When the deviation between the inner and outer rings is uniform, it indicates that the deviation is uniform.

[0039] Furthermore, the present invention can also obtain the height parameters of the iron core workpiece through the side first vision camera.

[0040] The present invention also provides a dual-view dimension detection system for automotive motor cores, which employs the dual-view dimension detection method for automotive motor cores as described above.

[0041] In summary, the present invention has the following beneficial effects:

[0042] In this solution, a first vision camera and a second vision camera can acquire relevant visual parameters of the iron core workpiece. The first vision camera can acquire the side parameters of the iron core workpiece from the side, directly obtaining its height and the width parameter W of its side projection, which is the outer diameter of the iron core workpiece. Furthermore, by adjusting the axis deflection of the iron core workpiece, the width parameters in different directions can be obtained. Based on the width parameters W from each viewpoint, the elliptical model of the outer ring of the iron core workpiece can be obtained, thus revealing the flattened shape of the iron core workpiece and determining whether it meets the accuracy standards.

[0043] In addition, the second vision camera can obtain a visual image of the end face from directly above the iron core workpiece, thereby enabling direct visual capture of the parameters of the outer and inner rings of the iron core workpiece. By using the parameters captured by the first and second vision cameras, dual verification can be achieved to determine whether the iron core workpiece has been flattened. Attached Figure Description

[0044] Figure 1 This is a first-view perspective perspective view of a dual-view dimension detection system for automotive motor cores according to this embodiment;

[0045] Figure 2 This is a second-view perspective perspective view of a dual-view dimension detection system for automotive motor cores according to this embodiment;

[0046] Figure 3 for Figure 2 Enlarged view of point A in the middle;

[0047] Figure 4 This is a perspective view of the iron core workpiece in this embodiment;

[0048] Figure 5 This is a top view of the iron core workpiece in this embodiment;

[0049] Figure 6 This is a top view of the iron core workpiece after rotation in this embodiment.

[0050] Reference numerals: 1. Inspection table; 11. First inspection position; 12. Second inspection position; 2. Rotary support fixture; 3. Iron core workpiece; 31. Outer ring; 32. Connecting rib; 33. Inner ring; 33. Arc-shaped body; 330. First vision camera; 4. Second vision camera; 5. Movable bracket; 6. Gripping robot; 7. Input track; 8. Input position; 81. Output track; 9. Rejection mechanism; 10. Detailed Implementation

[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] This embodiment discloses a dual-view dimension detection method for automotive motor cores. The first vision camera 4 can acquire the side parameters of the core workpiece 3 from the side, and can directly acquire the height parameter and the width parameter W of the side projection of the core workpiece 3. The width parameter W is the outer diameter value of the core workpiece 3.

[0053] Furthermore, by adjusting the axis deflection of the iron core workpiece 3, the width parameters of the iron core workpiece 3 in different directions can be obtained. Based on the width parameters W from each perspective, the elliptical model of the outer ring 31 of the iron core workpiece 3 can be obtained through the combination of multiple sets of data, thereby obtaining the flattened shape of the iron core workpiece 3 and determining whether the workpiece meets the accuracy standard.

[0054] In this embodiment, the solution can also obtain the height parameter of the iron core workpiece 3 through the side first vision camera 4. During the rotation process, the height parameter of the iron core workpiece 3 can be obtained through multiple vision acquisition directions, and the average height is used as the final height value.

[0055] Specifically, the dual-view dimension detection method for automotive motor cores in this embodiment includes the following steps:

[0056] The iron core workpiece 3 is placed vertically on the rotating support fixture 2 at the first detection position 11; the rotating support fixture 2 can rotate and keep the axis of rotation of the rotating support fixture 2 coaxial with the iron core workpiece 3, ensuring that the rotating support fixture 2 maintains a basically unchanged position during rotation.

[0057] Multiple sets of width data of the outer ring 31 are collected by the side first vision camera 4 in conjunction with the rotation of the iron core workpiece 3, and an elliptical model of the outer ring 31 is established to obtain the eccentricity between the center of the outer ring 31 and the ellipse.

[0058] The top view image is acquired by the second visual camera 5 at the top, the contours of multiple independent arc segments of the inner ring 33 are extracted, the center of each arc segment is fitted, and the overall center and concentricity deviation of the inner ring 33 are calculated.

[0059] By utilizing the overall center and concentricity deviation of the inner ring 33, the eccentricity of the outer ring 31 is double-verified.

[0060] In the detection scheme of this embodiment, the relevant visual parameters of the iron core workpiece 3 can be obtained through the first vision camera 4 and the second vision camera 5. The first vision camera 4 can collect images of the outer periphery of the iron core workpiece 3 from multiple perspectives, and can simultaneously obtain the height parameter H and the width parameter W. Thus, the height and outer diameter parameters of the iron core workpiece 3, as well as the roundness of the outer ring 31 of the iron core workpiece 3, can be obtained to determine whether the iron core workpiece 3 is slightly flattened.

[0061] Specifically, the outer ring 31 elliptical model of the iron core workpiece 3 is determined according to the rotation angle. The outer ring 31 elliptical model of the iron core workpiece 3 is constructed as follows:

[0062]

[0063] Where θ is the rotation angle of the iron core workpiece 3, W(θ) is the width data collected by the rotation angle θ of the iron core workpiece 3, a is the major semi-axis, b is the minor semi-axis, and φ is the initial deflection angle of the major axis of the ellipse.

[0064] Based on the major semi-axis a and minor semi-axis b in the elliptical model of the outer ring 31 of the core workpiece 3, the eccentricity e of the outer ring 31 of the core workpiece 3 is obtained. The eccentricity e is:

[0065]

[0066] When e=0, the outer ring 31 of the iron core workpiece 3 is a perfect circle. The larger the e is, the flatter the outer ring 31 of the iron core workpiece 3 is.

[0067] During the rotation acquisition process of the iron core workpiece 3, at least four sets of width data are acquired to form rotation angle and width data W(θi), i∈{1,2,3,…,n}, n≥4;

[0068] Choose any three sets from the n sets of data, and combine the data to form four sets of outer ring 31 ellipse models, and obtain the values ​​of the major semi-axis a and minor semi-axis b of the C(i,3) set: (ai,bi).

[0069] Specifically, the number of 'n' can be 4, where the four rotation angles are θ1=0°, θ2=α, θ3=2α, and θ4=3α, with α ranging from 50° to 80°. The angle α is generally set to 80 degrees to ensure that none of the four rotation angles are 180° apart, thus avoiding the acquisition of consistent width parameters in the width direction. After one rotation and until completely stationary, the visual parameter values ​​of the outer periphery of the iron core workpiece 3 are acquired through the first vision camera 4.

[0070] Choose any three sets from the four sets of data, and combine the data to form four sets of outer ring 31 ellipse models, resulting in C (4,3), and a total of four sets of values ​​for the major semi-axis a and minor semi-axis b: (a1,b1), (a2,b2), (a3,b3), (a4,b4).

[0071] Based on each group (a1, b1), (a2, b2), (a3, b3), and (a4, b4), obtain the mean and standard deviation of the major and minor semi-axis, where the mean is:

[0072]

[0073] The standard deviation is:

[0074]

[0075] When the standard deviation of the long and short semi-axis exceeds the threshold, it indicates that there is an error in the detection of the iron core workpiece 3, and it needs to be re-inspected.

[0076] When the standard deviations of both the major and minor semi-axis are less than the threshold, the test data is considered valid. The eccentricity e of the outer ring 31 of the core workpiece 3 is obtained based on the mean of the major and minor semi-axis. Further indicators can be set for the parameter of eccentricity e. When eccentricity e meets a certain threshold condition, it indicates that the core workpiece meets the test standard.

[0077] Reference Figures 4-6 As shown, in this embodiment, the core workpiece 3 includes an outer ring 31 and an inner ring 33. The inner ring 33 includes m independently distributed arc-shaped bodies 330. Each arc-shaped body 330 is fixedly connected to the inner circumference of the outer ring 31 through a connecting rib 32. Each arc-shaped body 330 maintains a standard circular arc, and its center shifts when the outer ring 31 is flattened. Specifically, the number of arc-shaped bodies 330 is six.

[0078] The second vision camera 5 can acquire a visual image of the end face from directly above the iron core workpiece 3, thereby enabling direct visual capture of the parameters of the outer ring 31 and inner ring 33 of the iron core workpiece 3. By using the parameters captured by the first vision camera 4 and the second vision camera 5, dual verification can be performed to determine whether the iron core workpiece 3 has been flattened.

[0079] Specifically, the second vision camera 5 can acquire the top-view visual parameters of the iron core workpiece 3, and can acquire the position Oj(Xj,Yj) of the center of each arc body 330 relative to the center of the elliptical model of the outer ring 31; that is, when the outer ring 31 is flattened, each arc body 330 of the inner ring 33 will be offset, but the arc body 330 is not easily affected because it is on the inner circumference of the outer ring 31. Therefore, the circumferential curve of each arc body 330 can be acquired visually, and then the position of the center of each arc body 330 can be acquired.

[0080] Specifically, taking the center of the outer ring elliptical model 31 as the origin (0,0), the center of each arc body 330 can be set to a position Oj(Xj,Yj) relative to this origin, where j∈{1,2,3,…,m}, j represents the sequence number of the arc body 330, and m represents the total number of arc bodies 330. In this embodiment, m=6.

[0081] Based on the center position Oj(Xj,Yj) of each arc body 330, the average center position of each arc body 330 is obtained, which is the overall center Oin(Xin,Yin) of the inner ring 33.

[0082] The overall center Oin(Xin,Yin) of the inner ring 33 is:

[0083]

[0084] Based on the center positions Oj(Xj,Yj) of each arc segment 330, the concentricity deviation of the inner ring 33 is obtained. The deviation between the center of the outer circle and the overall center of the inner ring 33 ;

[0085] in, for:

[0086]

[0087] in, for:

[0088]

[0089] when If the center positioning of outer ring 31 and inner ring 33 is valid when it is less than or equal to the threshold, it will be eliminated in the subsequent selection process.

[0090] The correlation is determined based on the ellipticity of outer ring 31 and the concentricity of inner ring 33, and a double correlation coefficient T is obtained to achieve dual verification of outer ring 31 and inner ring 33; the correlation coefficient T is:

[0091]

[0092] in, For calibration coefficients, This is the correlation threshold.

[0093] Correlation coefficient T and correlation threshold By comparison, the deviation between the inner ring 33 and the outer ring 31 of the core workpiece 3 is determined.

[0094] When the correlation coefficient T This indicates that the deviation between the inner ring 33 and the outer ring 31 is uniform, which meets the comprehensive standard of the two detection processes.

[0095] This embodiment also discloses a dual-view dimension detection system for automotive motor cores, which adopts the dual-view dimension detection method for automotive motor cores as described above.

[0096] Reference Figures 1-6 As shown, the detection system in this embodiment includes a detection platform 1, an input track 8 and an output track 9. The upper part of the input track 8 has a first detection position 11 and a second detection position 12, which can place the iron core workpiece 3 to be detected at the two detection positions respectively, and perform visual detection on the iron core workpiece 3 through a vision camera.

[0097] In this embodiment, two sets of vision cameras are provided: a first vision camera 4 and a second vision camera 5. The first vision camera 4 is arranged horizontally and can be directly facing the side of the iron core workpiece 3 placed at the first detection position 11, thereby acquiring the height and width parameters of the iron core workpiece 3. The image of the iron core workpiece 3 captured by the first vision camera 4 is roughly rectangular in structure.

[0098] A rotating support fixture 2 is installed at the first detection position 11. The bottom of the rotating support fixture 2 is driven to rotate by a rotating driver, and the rotation angle can be controlled. During the detection process, the rotation of the rotating support fixture 2 can cause the iron core workpiece 3 to rotate, for example, by a rotation angle θ, thereby changing the direction of the iron core workpiece 3 facing the first vision camera 4. Then, the first vision camera 4 visually captures the width values ​​of the iron core workpiece 3 in different directions.

[0099] The second vision camera 5 is arranged vertically, located directly above the second detection position 12, and is capable of visually capturing the end face shape of the iron core workpiece 3 placed at the second detection position 12. The end face shape of the iron core workpiece 3 is roughly an annular structure, including an outer ring 31 and an inner ring 33. The outer ring 31 is a complete circular ring; the inner ring 33 has a segmented structure, including several arc-shaped bodies 330. The outer periphery of each arc-shaped body 330 is fixedly connected to the inner periphery of the outer ring 31 by connecting ribs 32.

[0100] The second vision camera 5 can acquire visual images of the end face of the iron core workpiece 3. For the outer ring 31, its outer diameter and roundness can be acquired. For each arc segment 330, the center position of each arc segment 330 can be acquired, and thus the relative positional relationship of each arc segment 330 can be acquired.

[0101] An input track 8 and an output track 9 are respectively provided on both sides of the inspection table 1. The input track 8 is located on the side closer to the first inspection position 11, and the output track 9 is located on the side closer to the second inspection position 12. The input track 8, the output track 9 and the inspection table 1 are roughly the same, which can ensure that the iron core workpiece 3 can be transferred and transported normally. An input position 81 is formed at one end of the input track 8. When the iron core workpiece 3 is transported to this input position, the iron core workpiece 3 can be accurately positioned, which facilitates subsequent gripping and movement.

[0102] The output track 9 is used to output the tested iron core workpiece 3, and a rejection mechanism 10 is set in the middle section of the output track 9. The rejection mechanism 10 can distinguish between qualified and unqualified iron core workpieces 3.

[0103] For the transfer and conveying of the iron core workpiece 3, a suitable gripping robot 7 is used for clamping, which can sequentially transport the workpiece from the input position 81 of the input track 8, the first detection position 11, the second detection position 12, and the output track 9. The gripping robot 7 can be specifically configured according to the gripping needs. The gripping robot 7 is mounted on the movable support 6. By moving the movable support 6, the gripping robot 7 and the iron core workpiece 3 it grips can move synchronously.

[0104] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for dual-view dimensional inspection of automotive motor cores, characterized in that, Including the following steps: The iron core workpiece is placed vertically, and multiple sets of outer ring width data are collected by the side first vision camera in conjunction with the rotation of the iron core workpiece. An outer ring elliptical model is established to obtain the eccentricity between the outer ring center and the ellipse. The top view image is acquired by the second visual camera at the top, the contours of multiple independent arc segments of the inner ring are extracted, the center of each arc segment is fitted, and the overall center and concentricity deviation of the inner ring are calculated. By utilizing the overall center and concentricity deviation of the inner ring, the eccentricity of the outer ring's center and ellipse is double-verified. The outer ring elliptical model of the iron core workpiece is based on the rotation angle The outer elliptical model of the iron core workpiece is constructed as follows: Where θ is the angle of rotation of the iron core workpiece, W(θ) is the width data collected by the rotation angle θ of the iron core workpiece, a is the major semi-axis, b is the minor semi-axis, The initial deflection angle of the major axis of the ellipse; During the rotation data acquisition process of the iron core workpiece, four sets of width data are collected to form rotation angle and width data W(θi), i∈{1,2,3,…,n}, n≥4; θ1=0°, θ2=α, θ3=2α, θ4=3α, the range of α is 50°-80°; Choose any three sets from the n sets of data, and combine the data to form four sets of outer ring ellipse models, and obtain the values ​​of the major semi-axis a and minor semi-axis b of C(i,3): (ai,bi); Based on each group (ai, bi), obtain the mean and standard deviation of the major and minor semi-axis. The mean is: The standard deviation is: When the standard deviations of both the long and short semi-axis are less than the threshold, it indicates that the detection data of the long and short semi-axis are valid. The eccentricity e of the outer ring of the iron core workpiece is obtained based on the mean of the long and short semi-axis. The correlation coefficient T is determined based on the ellipticity of the outer ring and the concentricity of the inner ring, thus achieving dual verification of the outer and inner rings. The correlation coefficient T is: in, For calibration coefficients, For the correlation threshold, This refers to the concentricity deviation of the inner ring. When the correlation coefficient T When the deviation between the inner and outer rings is uniform, it indicates that the deviation is uniform.

2. The method for dual-view dimension detection of automotive motor core according to claim 1, characterized in that, Based on the major semi-axis a and minor semi-axis b in the outer ring elliptical model of the iron core workpiece, the eccentricity e of the outer ring of the iron core workpiece is obtained. The eccentricity e is: When e=0, the outer ring of the iron core workpiece is a perfect circle. The larger the e is, the flatter the outer ring of the iron core workpiece is.

3. The method for dual-view dimension detection of automotive motor core according to claim 1, characterized in that, The core workpiece includes an inner ring, which comprises m independently distributed arc-shaped bodies. Each arc-shaped body is fixedly connected to the inner circumference of the outer ring through connecting ribs. Each arc-shaped body maintains a standard circular arc, and its center shifts when the outer ring is flattened. Obtain the position Oj(Xj,Yj) of the center of each arc segment relative to the center of the outer ring ellipse model; The overall center Oin(Xin,Yin) of the inner ring is: Where j∈{1,2,3,…,m}, j represents the index of the arc shape, and m represents the total number of arc shapes.

4. The method for dual-view dimension detection of automotive motor core according to claim 3, characterized in that, Based on the center positions Oj(Xj,Yj) of each arc segment, the concentricity deviation of the inner ring is obtained. The deviation between the center of the outer circle and the overall center of the inner ring ; for: for: when When the value is less than or equal to the threshold, the center positioning of the outer and inner rings is considered valid.

5. The method for dual-view dimension detection of automotive motor core according to claim 1, characterized in that, The height parameters of the iron core workpiece can also be obtained through the side-view camera.

6. A dual-view dimension detection system for automotive motor cores, characterized in that, The dual-view dimension detection method for automotive motor cores as described in any one of claims 1-5 is adopted.

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