Laser spot automatic adjusting device and method for load monitoring of porcelain post insulator

Abstract

The application discloses a kind of laser spot automatic adjusting device and method of support column porcelain insulator load monitoring.The laser spot automatic adjusting device of the application includes galvanometer module for laser spot position adjustment, dynamic focusing mirror for laser beam focusing, visual measurement module for spot capture and positioning and control software for the collaborative control among visual measurement module, galvanometer module and dynamic focusing mirror.The laser spot automatic adjusting method of the application includes the capture of insulator edge straight line and spot centroid using visual measurement module, spot spacing and skew angle measurement, guiding galvanometer module and focusing mirror to flexibly adjust spot position, and through the circular arc surface laser spot position control method based on the combination of galvanometer module adjustment and visual guidance, realizing long-distance, high-precision excitation and reception of laser ultrasonic signal.The application solves the problem of poor flexibility and precision of laser position adjustment caused by the characteristics of circular arc surface and long-distance measurement of support column insulator.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of stress monitoring of power grid post porcelain insulators, and particularly relates to a laser spot automatic adjusting device and method for post porcelain insulator load monitoring. BACKGROUND

[0002] The post porcelain insulator plays a supporting and insulating role in the power transmission and distribution link, and will suddenly break due to the action of complex stress in the service process, causing serious safety accidents. Therefore, the stress condition of the post porcelain insulator needs to be measured. Among many load measurement methods, laser ultrasonic has become a research hotspot for load measurement of post porcelain insulators at present because of its long distance, high precision and other advantages, and has the potential to become an important means for insulator load monitoring under a live condition.

[0003] The basic principle of laser ultrasonic measurement of insulators is based on the acoustic-elastic effect, that is, there is a linear or nonlinear relationship between the acoustic velocity of ultrasonic propagation and the load. By accurately measuring the acoustic velocity of ultrasonic propagation, the load can be accurately calculated. Since the ultrasonic velocity measurement mainly uses the principle of propagation distance divided by propagation time. For laser ultrasonic, when high-resolution instruments are used to ensure the measurement accuracy of the propagation time, accurate measurement and control of the ultrasonic propagation distance (i.e. the spot spacing) become the key to load measurement.

[0004] The existing laser ultrasonic system is mainly suitable for the limitation of planar component measurement. In view of the characteristics of the circular arc surface and long distance measurement of the post insulator, the laser spot adjustment has the problems of low flexibility of position adjustment and poor precision, and there are still some improvements to be made in the actual measurement application process.

[0005] Firstly, the laser spot of the excitation laser and the laser spot of the receiving laser need to be adjusted to the specified area during laser ultrasonic measurement. The current laser ultrasonic system has low automation degree, and needs to be adjusted manually by deflection mirrors and other tools, so the long distance measurement has the problems of complicated and low efficient instrument adjustment process.

[0006] Secondly, the laser ultrasonic load measurement needs to accurately measure the spot spacing between the excitation spot and the receiving laser. Accurate spot spacing measurement is the key to realizing the ultrasonic propagation velocity and high-precision load measurement. However, since the post insulator is an arc structure, when the two light spots are incident on the surface of the insulator, the spacing is actually arc-shaped, which needs to be further corrected.

[0007] Therefore, in order to improve the precision and efficiency of the existing laser ultrasonic load measurement equipment and method, a laser spot automatic adjusting device and method for post porcelain insulator load monitoring are urgently needed to be developed. SUMMARY

[0008] The application aims to provide a laser spot automatic adjusting device and method for support porcelain insulator load monitoring, so as to solve the problem of poor flexibility and precision of laser position adjustment caused by the arc surface and long-distance measurement characteristics of the support insulator.

[0009] To solve the above technical problems, the application adopts a technical solution of a laser spot automatic adjusting device for support porcelain insulator load monitoring, which comprises:

[0010] A galvanometer module for adjusting the laser spot position;

[0011] A dynamic focusing mirror for focusing the laser beam;

[0012] A visual measurement module for spot capturing and positioning;

[0013] Control software for the coordinated control among the visual measurement module, the galvanometer module and the dynamic focusing mirror.

[0014] Further, the galvanometer module, the dynamic focusing mirror and the visual measurement module are arranged and fixed in an optical coaxial manner.

[0015] Another technical solution adopted by the application is a laser spot automatic adjusting method for support porcelain insulator load monitoring, which adopts the above-mentioned laser spot automatic adjusting device for support porcelain insulator load monitoring, uses the visual measurement module to realize the capturing of the insulator edge straight line and the spot centroid, the measurement of the spot spacing and the deflection angle, and guides the galvanometer module and the dynamic focusing mirror to flexibly adjust the spot position; through the circular arc surface laser spot position control method based on the combination of the galvanometer module adjustment and the visual guidance, the long-distance and high-precision excitation and reception of the laser ultrasonic signal are realized.

[0016] Further, the visual measurement module realizes the following steps:

[0017] S1. The visual measurement module is used to perform image acquisition and processing of the insulator and the laser spot irradiated on the insulator, 32-bit color pictures are obtained and processed into 8-bit gray scale picture matrixes;

[0018] S2. The K-means algorithm is used to perform segmentation processing of the gray scale pictures, and the elbow method and the contour coefficient method are used to determine the cluster number;

[0019] S3. The probability Hough transformation is performed on the gray scale picture after cluster segmentation, and the edge straight line of the support porcelain insulator in the gray scale picture is detected to obtain the insulator edge straight line coordinate matrix;

[0020] S4. The pixel diameters of the two edges of the insulator in the gray scale picture are calculated, the actual diameter of the insulator of this model is inquired, the ratio between the actual diameter and the pixel diameter of the insulator is calculated to obtain a proportion factor M;

[0021] S5. Further detect the grayscale image after probability Hough transform, extract the laser spot contour, and obtain the laser spot contour matrix;

[0022] S6. Calculate the centroid coordinates of the excitation spot and the receiving spot using the obtained laser spot contour matrix, and calculate the distance between the centroid coordinates of the laser spot;

[0023] S7. Multiply the distance between the centroid coordinates of the laser spot by the scaling factor M described in step S4 to obtain the straight-line distance S of the laser spot;

[0024] S8. Calculate the angle between the line connecting the centroids of the two laser spots and the edge line of the insulator, and record it as the deflection angle θ.

[0025] S9. Using the straight-line distance S of the laser spot and the skew angle θ, calculate the actual distance S between the two laser spots on the arc surface according to the equation of the cylindrical surface of the insulator. r .

[0026] Furthermore, using the galvanometer module, the type of stress to be measured is adjusted by setting and comparing the skew angle θ obtained by the visual measurement module. When the skew angle is set to 0°, it is used as the bending stress measurement mode, and when the skew angle is set to 90°, it is used as the torsional stress measurement mode.

[0027] Furthermore, by setting and comparing the actual distance S of the light spot obtained by the visual measurement module... r Accurately calculate the sound velocity and load value of ultrasonic propagation.

[0028] Furthermore, after completing the visual measurement, the focusing state of the laser is adjusted using the dynamic focusing mirror so that the laser is focused on the surface of the insulator.

[0029] Furthermore, in step S2, the parameters of the K-means algorithm are set as follows: the maximum number of iterations is 10, the minimum convergence threshold is 1.0, and the optimal number of clusters is 3.

[0030] The beneficial effects of this invention are as follows:

[0031] This invention can achieve full coverage of the scanning range of post porcelain insulators by using a pulsed laser, a galvanometer module, and a dynamic focusing lens, while protecting the glaze layer on the surface of the insulator from damage.

[0032] This invention achieves long-distance, high-precision excitation and reception of laser ultrasonic signals by combining galvanometer module adjustment and visual guidance to control the position of laser spot on an arc surface. This solves the problems of poor flexibility and accuracy in laser position adjustment caused by the arc surface and long-distance measurement characteristics of post insulators. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the device in a specific embodiment of the present invention;

[0035] Figure 2 This is a flowchart illustrating the method in a specific embodiment of the present invention. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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.

[0037] Example 1

[0038] This embodiment provides an automatic laser spot adjustment device for monitoring the load of post porcelain insulators, such as... Figure 1 As shown, the system includes a galvanometer module for adjusting the laser spot position, a dynamic focusing mirror for focusing the laser beam, a vision measurement module for spot capture and positioning, and control software. The control software is used for the coordinated control of the vision measurement module, the galvanometer module, and the dynamic focusing mirror.

[0039] The galvanometer module, dynamic focusing lens, and visual measurement module are arranged and fixed in an optically coaxial manner.

[0040] Example 2

[0041] This embodiment provides an automatic laser spot adjustment method for load monitoring of post porcelain insulators. It adopts the automatic laser spot adjustment device for load monitoring of post porcelain insulators described in Embodiment 1. It uses a vision measurement module to grasp the straight line of the insulator edge and the centroid of the laser spot, and to measure the laser spot spacing and skew angle, guiding the galvanometer module and dynamic focusing lens to flexibly adjust the laser spot position. Through the laser spot position control method on the arc surface based on the combination of galvanometer module adjustment and vision guidance, long-distance, high-precision excitation and reception of laser ultrasonic signals are achieved.

[0042] like Figure 2 As shown, the visual measurement module implements the following steps:

[0043] S1. Image acquisition: image acquisition of the insulator and the laser spot irradiated on the insulator is performed by using a visual measurement module, 32-bit color pictures are obtained for image processing, and 8-bit grayscale image matrix is processed.

[0044] S2. Image segmentation: K-means image segmentation algorithm is used for segmentation processing of the grayscale image, the maximum iteration number is set to 10 times, and the minimum convergence threshold is 1.0. The elbow method and contour coefficient method are used to determine that the optimal cluster number is 3.

[0045] S3. Probability Hough transform: the grayscale image after clustering segmentation is subjected to probability Hough transform, and the edge straight line of the support porcelain insulator in the grayscale image is detected to obtain the insulator edge straight line coordinate matrix.

[0046] S4. Proportion factor calculation: the pixel diameter of the two edges of the insulator in the grayscale image is 312 mm, the actual diameter of the insulator of this model is 318 mm, the ratio of the actual diameter of the insulator to the pixel diameter is calculated, and the proportion factor M = 1.02 is obtained.

[0047] S5. Laser spot profile extraction: the grayscale image after probability Hough transform is further detected to extract the laser spot profile, and the laser spot profile matrix is obtained.

[0048] S6. Insulator profile extraction: the obtained spot profile matrix is used to calculate the excitation spot and receiving spot profile centroid coordinates respectively, and the centroid coordinate distance is 22.4 mm.

[0049] S7. Spot straight line distance calculation: the laser spot centroid coordinate distance is multiplied by the proportion factor M described in step S4 to obtain the laser spot straight line distance S = 22.85 mm; S8. Galvanometer angle adjustment: the included angle between the line connecting the two laser spot centroids and the edge line of the insulator is calculated, and the deflection angle θ is recorded; the deflection angle is adjusted to 90° by using the galvanometer module, which is used as the torsional stress measurement mode.

[0050] S9. Spot arc surface distance calculation: the laser spot straight line distance S and the deflection angle θ are used to calculate the actual distance S of the two spots on the circular arc surface according to the insulator cylindrical surface equation, which is 23.86 mm and is used for subsequent sound velocity and load calculation. r

[0051] ​Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not intended to limit the same; although the present application has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that the technical solutions recorded in the foregoing examples can still be modified, or some of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A laser spot automatic adjusting method for load monitoring of a post porcelain insulator, which adopts a laser spot automatic adjusting device, characterized in that, The laser spot automatic adjusting device comprises: a galvanometer module for adjusting the laser spot position; a dynamic focusing mirror for focusing the laser beam; a visual measurement module for spot capturing and positioning; control software for the coordinated control among the visual measurement module, the galvanometer module and the dynamic focusing mirror; the laser spot automatic adjusting method comprises: the visual measurement module is used to capture the insulator edge straight line and the spot centroid, calculate the laser spot centroid coordinate distance and the deflection angle, obtain the laser spot straight line distance from the laser spot centroid coordinate distance, and calculate the actual distance of the two laser spots on the arc surface according to the insulator cylindrical surface equation, using the laser spot straight line distance and the deflection angle, to guide the galvanometer module and the dynamic focusing mirror to flexibly adjust the spot position; the laser ultrasonic signal excitation and reception with long distance and high precision are realized through the arc surface laser spot position control method based on the combination of the galvanometer module adjustment and visual guidance.

2. The laser spot automatic adjusting method for load monitoring of a post porcelain insulator according to claim 1, characterized in that, The galvanometer module, the dynamic focusing mirror and the visual measurement module are arranged and fixed in an optical coaxial manner.

3. The laser spot automatic adjusting method for load monitoring of a post porcelain insulator according to claim 1, characterized in that, The visual measurement module realizes the following steps: S1. the visual measurement module is used to collect and process the images of the insulator and the laser spot irradiated on the insulator, to obtain a 32-bit color picture and process it into an 8-bit grayscale picture matrix; S2. the K-means algorithm is used to segment and process the grayscale image, and the elbow method and the contour coefficient method are used to determine the cluster number; S3. the probability Hough transform is performed on the grayscale image after cluster segmentation, and the straight line of the edge of the support porcelain insulator in the grayscale image is detected, to obtain the insulator edge straight line coordinate matrix; S4. the pixel diameters of the two edges of the insulator in the grayscale image are calculated, the actual diameter of the insulator of this model is inquired, the ratio of the actual diameter of the insulator to the pixel diameter is calculated, and the proportion factor M is obtained; S5. the grayscale image after the probability Hough transform is further detected, the laser spot contour is extracted, and the laser spot contour matrix is obtained; S6. the laser spot contour matrix is used to calculate the excitation spot and the receiving spot contour centroid coordinates respectively, and the laser spot centroid coordinate distance is calculated; S7. the laser spot straight line distance S is obtained by multiplying the laser spot centroid coordinate distance by the proportion factor M in step S4; S8. the included angle between the two laser spot centroid connecting lines and the insulator edge line is calculated, and recorded as the deflection angle θ. S9. With the linear distance S and the skew angle θ of the laser spot, the actual distance S of the two spots on the circular arc surface is calculated according to the cylindrical surface equation of the insulator r .

4. The laser spot automatic adjusting method for load monitoring of a post porcelain insulator according to claim 3, characterized in that, The galvanometer module is used to adjust and compare the deflection angle θ obtained by the visual measurement module, and adjust the type of the measurement stress; when the deflection angle is set to 0°, it is used as the bending stress measurement mode; and when the deflection angle is set to 90°, it is used as the torsional stress measurement mode.

5. The laser spot automatic adjusting method for load monitoring of a post porcelain insulator according to claim 3, characterized in that, By setting and comparing the actual distance S of the light spot obtained by the visual measurement module r , the ultrasonic propagation speed and the load value are accurately calculated.

6. The laser spot automatic adjusting method for load monitoring of a post porcelain insulator according to claim 3, characterized in that, After the visual measurement is completed, the dynamic focusing mirror is used to adjust the focusing state of the laser, so that the laser is focused on the surface of the insulator.

7. The laser spot automatic adjusting method for load monitoring of a post porcelain insulator according to claim 3, characterized in that, In step S2, the parameters of the K-means algorithm are set as follows: the maximum iteration number is 10 times, the minimum convergence threshold is 1.0, and the optimal cluster number is 3.

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