Method for measuring the light output quality of a laser welding torch

Abstract

The application discloses a kind of measurement methods of laser welding gun light output quality, it is related to welding equipment field, wherein, measurement method includes: when the test beam of laser welding gun is imaged in the attenuation imaging area of imaging sheet and generates beam imaging, imaging sheet is photographed using camera, and imaging sheet image is obtained, wherein, imaging sheet also includes background area and reference area, at least one reference is provided in reference area;Imaging sheet image is converted into gray image, beam imaging in gray image is identified, and beam imaging information is obtained by calculation, reference in gray image is identified, and reference information is obtained by calculation;According to reference information and beam imaging information, target measurement parameter is obtained by calculation.The application realizes the efficient and high-precision measurement of laser welding gun light output quality.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of welding equipment, in particular to a method for measuring light output quality of a laser welding gun. BACKGROUND

[0002] Before leaving the factory or during maintenance, the light output quality of a laser welding gun usually needs to be measured. In related technologies, common methods for measuring light output quality include using measuring tools such as tool gauges and rulers to determine the shape and position of a test light beam by the human eye, or using thermal sensitive target paper for inspection. However, both methods have the problems of low measurement accuracy and low measurement efficiency. SUMMARY

[0003] The main purpose of the present application is to provide a method for measuring light output quality of a laser welding gun, aiming to solve the technical problems of low measurement accuracy and low measurement efficiency of light output quality of a laser welding gun.

[0004] To achieve the above purpose, the present application provides a method for measuring light output quality of a laser welding gun, comprising:

[0005] When a test light beam of a laser welding gun irradiates an attenuation imaging area of an imaging sheet to generate light beam imaging, a camera is used to shoot the imaging sheet to obtain an imaging sheet image, wherein the imaging sheet further comprises a background area and a reference object area, and at least one reference object is arranged in the reference object area;

[0006] The imaging sheet image is converted into a gray scale image, the light beam imaging in the gray scale image is identified, light beam imaging information is calculated and obtained, and the reference object in the gray scale image is identified, reference object information is calculated and obtained;

[0007] According to the reference object information and the light beam imaging information, a target measurement parameter is calculated and obtained.

[0008] In an embodiment, the identification of the reference object in the gray scale image and the calculation and obtaining of the reference object information comprises:

[0009] The contour of a reference circle in the gray scale image is extracted, and the pixel size of the reference circle is calculated and obtained;

[0010] According to the pixel size and the physical size of the reference circle, a conversion coefficient between the pixel amount and the physical amount of the reference object is calculated and obtained.

[0011] In an embodiment, the identification of the light beam imaging in the gray scale image and the calculation and obtaining of the light beam imaging information comprises:

[0012] When the light beam imaging is a static light spot, the contour of the static light spot is identified, and the pixel size of the static light spot is calculated and obtained;

[0013] The calculating the target measurement parameter according to the reference information and the light beam imaging information comprises:

[0014] The calculating the physical size of the static light spot according to the conversion coefficient and the pixel size of the static light spot.

[0015] In an embodiment, the center of the reference circle is located on the central axis of the welding nozzle of the laser welding gun.

[0016] After the step of extracting the contour of the reference circle in the gray-scale image, the method further comprises:

[0017] The calculating the center position information of the reference circle according to the contour of the reference circle comprises:

[0018] The calculating the light beam imaging information according to the identification of the light beam imaging in the gray-scale image comprises:

[0019] When the light beam imaging is a static light spot, the calculating the focal point position information of the static light spot according to the identification of the contour of the static light spot comprises:

[0020] The calculating the target measurement parameter according to the reference information and the light beam imaging information comprises:

[0021] The calculating the misalignment deviation pixel amount of the light beam focal point and the welding nozzle according to the center position information of the reference circle and the focal point position information of the static light spot comprises:

[0022] The calculating the misalignment deviation physical amount of the light beam focal point and the welding nozzle according to the misalignment deviation pixel amount and the conversion coefficient.

[0023] In an embodiment, the calculating the light beam imaging information according to the identification of the light beam imaging in the gray-scale image comprises:

[0024] When the light beam imaging is a galvanometer light spot, the calculating the length pixel amount of the galvanometer light spot according to the extracting the contour of the galvanometer light spot in the gray-scale image comprises:

[0025] The calculating the target measurement parameter according to the reference information and the light beam imaging information comprises:

[0026] The calculating the swing width of the galvanometer light spot according to the length pixel amount of the galvanometer light spot and the conversion coefficient.

[0027] In an embodiment, after the calculating the swing width of the galvanometer light spot according to the length pixel amount of the galvanometer light spot and the conversion coefficient, the method further comprises:

[0028] The calculating the run-out value of the laser welding gun according to the swing widths of the galvanometer light spots of two continuous periods.

[0029] In an embodiment, the reference object comprises a reference straight line;

[0030] The identifying the reference object in the gray-scale image and calculating the reference object information comprises:

[0031] Extracting the reference straight line in the gray-scale image and calculating the position information of the reference straight line;

[0032] The identifying the light beam imaging in the gray-scale image and calculating the light beam imaging information comprises:

[0033] When the light beam imaging is a galvanometer spot, extracting the contour of the galvanometer spot in the gray-scale image and calculating the position information of the target edge of the galvanometer spot;

[0034] The calculating the target measurement parameter according to the reference object information and the light beam imaging information comprises:

[0035] According to the position information of the reference straight line and the position information of the target edge of the galvanometer spot, the beam swing angle deviation of the laser welding gun is calculated.

[0036] In an embodiment, the extracting the contour of the galvanometer spot in the gray-scale image comprises:

[0037] According to the contour of the galvanometer spot, the correction contour of the galvanometer spot is calculated, wherein the correction contour is the minimum circumscribed rectangle of the contour of the galvanometer spot.

[0038] In an embodiment, before the step of using a camera to shoot an imaging sheet and obtaining an imaging sheet image, the method further comprises:

[0039] Using a light source to irradiate the imaging sheet with a target power, the target power satisfying the following constraint condition:

[0040]

[0041] Wherein, n is the target gray-scale ratio, P is the target power, K1 is the reflection coefficient of the attenuation imaging area, and L1 is the brightness of the light beam imaging.

[0042] In an embodiment, the extracting the contour of the reference circle in the gray-scale image comprises:

[0043] Identifying the edge points of the reference circle in the gray-scale image;

[0044] Fitting the edge points into a circle to obtain the contour of the reference circle.

[0045] One or more technical solutions proposed in the present application have at least the following technical effects:

[0046] A laser welding gun light output quality measurement method is provided. When a test beam of the laser welding gun irradiates an attenuation imaging area of an imaging sheet to generate a light beam image, an imaging sheet image is obtained by using a camera to shoot the imaging sheet, the imaging sheet image is converted into a gray scale image, light beam imaging in the gray scale image is identified, light beam imaging information is calculated and obtained, a reference object in the gray scale image is identified, reference object information is calculated and obtained, target measurement parameters are calculated and obtained according to the reference object information and the light beam imaging information, and efficient and high-precision measurement of the laser welding gun light output quality is realized. BRIEF DESCRIPTION OF DRAWINGS

[0047] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate embodiments consistent with the present application and, together with the description, further serve to explain the principles of the application.

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the accompanying drawings needed to be used in the embodiments or related art description will be briefly introduced. Obviously, for those of ordinary skill in the art, other drawings can also be obtained without creative labor based on these drawings.

[0049] Figure 1 A flowchart of a first embodiment of the laser welding gun light output quality measurement method provided by the present application is shown in the figure.

[0050] Figure 2 A structure diagram of an imaging sheet is shown in the figure.

[0051] Figure 3 A component position diagram is shown in the figure.

[0052] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0053] It should be understood that the specific embodiments described herein are only used to explain the technical solutions of the present application and not to limit the present application. In order to better understand the technical solutions of the present application, the specific embodiments will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0054] In the first embodiment of the laser welding gun light output quality measurement method of the present application, the reference Figure 1 , Figure 1 A flowchart of the present embodiment is shown in the figure. The laser welding gun light output quality measurement method can include steps S10-S30.

[0055] Step S10, when the test light beam of the laser welding gun irradiates the attenuation imaging area of the imaging sheet to generate light beam imaging, the imaging sheet is photographed by using a camera to obtain an imaging sheet image, wherein the imaging sheet further includes a background area and a reference object area, and at least one reference object is arranged in the reference object area.

[0056] It should be noted that the test light beam irradiates the attenuation imaging area, and the light beam imaging is generated in the attenuation imaging area after diffuse reflection and attenuation, wherein the light beam imaging is a static spot or a galvanometer spot after being photographed by the camera, the galvanometer spot is obtained by modulating light by a galvanometer, and the reference object is a geometric element, such as a circle, a rectangle and a straight line. After the imaging sheet is photographed by the camera, the imaging sheet image obtained includes the background area, the reference object area, the attenuation imaging area and the light beam imaging.

[0057] In a feasible implementation, the test light beam is red visible light, which can improve the identification of the light beam imaging and will not cause secondary influence on the imaging sheet, so that the imaging sheet can be repeatedly used.

[0058] In a feasible implementation, the reference Figure 2 As shown in the imaging sheet structure schematic diagram, the background area of the imaging sheet is black, the reference object area is white, the reference object includes a reference straight line and a reference circle, and the attenuation imaging area is located in the reference circle and is black. Through the above configuration, the brightness of the three areas in the imaging sheet image is significantly different, which can effectively improve the accuracy of the later image recognition. Optionally, the reference object area is made of a metal luster material, the attenuation imaging area of the imaging sheet can be composed of black paper and an attenuation film, or can be composed of black silk printing and an attenuation film, which provides attenuation and diffuse reflection functions.

[0059] Step S20, converting the imaging sheet image into a gray scale image, identifying the light beam imaging in the gray scale image, calculating to obtain light beam imaging information, identifying the reference object in the gray scale image, and calculating to obtain reference object information.

[0060] Step S30, calculating to obtain a target measurement parameter according to the reference object information and the light beam imaging information.

[0061] The measurement method of the light output quality of the laser welding gun in the embodiment realizes efficient and high-precision measurement of the light output quality of the laser welding gun by the following steps: when the test light beam of the laser welding gun irradiates the attenuation imaging area of the imaging sheet to generate light beam imaging, the imaging sheet is photographed by using a camera to obtain an imaging sheet image, the imaging sheet image is converted into a gray scale image, the light beam imaging in the gray scale image is identified, light beam imaging information is calculated and obtained, the reference object in the gray scale image is identified, reference object information is calculated and obtained, and a target measurement parameter is calculated and obtained according to the reference object information and the light beam imaging information.

[0062] In a feasible implementation, the measurement method of the embodiment is used to measure the physical size of the static spot of the laser welding gun, and step S20 can include steps A11-A12:

[0063] Step A11, the contour of the reference circle in the gray-scale image is extracted, and the pixel size of the reference circle is calculated; and the conversion coefficient between the pixel quantity and the physical quantity of the reference object is calculated according to the pixel size and the physical size of the reference circle.

[0064] It should be noted that the pixel size of the reference circle can be the pixel quantity of the diameter of the reference circle or the pixel quantity of the radius of the reference circle, and correspondingly, the physical size of the reference circle is the physical quantity of the diameter or the radius of the reference circle, and the conversion coefficient can be expressed by the ratio of the pixel size to the physical size or the ratio of the physical size to the pixel size.

[0065] Step A12, when the light beam is imaged as a static spot, the contour of the static spot is identified, and the pixel size of the static spot is calculated.

[0066] Correspondingly, step S30 can include step B11:

[0067] Step B11, the physical size of the static spot is calculated according to the conversion coefficient and the pixel size of the static spot.

[0068] In a feasible implementation, the measurement method of the embodiment is used to measure the physical quantity of the centering deviation of the static spot of the laser welding gun, the center of the reference circle is located on the center axis of the welding nozzle of the laser welding gun, and step S20 can include steps A21-A23:

[0069] Step A21, the contour of the reference circle in the gray-scale image is extracted, and the pixel size of the reference circle is calculated; and the conversion coefficient between the pixel quantity and the physical quantity of the reference object is calculated according to the pixel size and the physical size of the reference circle.

[0070] Step A22, the center position information of the reference circle is calculated according to the contour of the reference circle.

[0071] Step A23, when the light beam is imaged as a static spot, the contour of the static spot is identified, and the focal point position information of the static spot is calculated.

[0072] Correspondingly, step S30 can include steps B21-B22:

[0073] Step B21, the centering deviation pixel quantity of the light beam focal point and the welding nozzle is calculated according to the center position information of the reference circle and the focal point position information of the static spot.

[0074] Step B22, according to the quantity of the centering deviation pixels and the conversion coefficient, the quantity of the centering deviation of the beam focus and the welding nozzle is calculated.

[0075] In a specific embodiment, the gray scale image is fitted with circles based on a preset gray scale critical value, a plurality of circles can be fitted, wherein the largest circle is the contour of the reference circle, and the smallest circle is the contour of the static light spot. The fitted circles can be sorted in ascending or descending order based on the diameter or radius, and the contours of the reference circle and the static light spot can be quickly obtained.

[0076] In a feasible embodiment, the measurement method of the embodiment is used to measure the swing width of the galvanometer light spot of the laser welding gun, and step S20 can include steps A31-A32.

[0077] Step A31, the contour of the reference circle in the gray scale image is extracted, and the pixel size of the reference circle is calculated. According to the pixel size and the physical size of the reference circle, the conversion coefficient between the pixel quantity and the physical quantity of the reference object is calculated.

[0078] Step A32, when the light beam is imaged as a galvanometer light spot, the contour of the galvanometer light spot in the gray scale image is extracted, and the length pixel quantity of the galvanometer light spot is calculated.

[0079] Correspondingly, step S30 can include step B31.

[0080] Step B31, according to the length pixel quantity of the galvanometer light spot and the conversion coefficient, the swing width of the galvanometer light spot is calculated.

[0081] It should be noted that when the camera is used to shoot the galvanometer light spot, the exposure time of the camera is greater than one complete scanning period of the galvanometer.

[0082] In a feasible embodiment, the measurement method of the embodiment is used to measure the jumping value of the galvanometer light spot of the laser welding gun, and after step B31, step S30 can further include step B32.

[0083] Step B32, according to the swing widths of the galvanometer light spots of two consecutive periods, the jumping value of the laser welding gun is calculated.

[0084] In a feasible embodiment, the measurement method of the embodiment is used to measure the beam swing angle deviation of the laser welding gun, and the reference object includes a reference straight line; step S20 can include steps A41-A42.

[0085] Step A41, the reference straight line in the gray scale image is extracted, and the position information of the reference straight line is calculated.

[0086] Step A42, when the light beam is imaged as a galvanometer spot, extracting the contour of the galvanometer spot in the gray image, and calculating to obtain the position information of the target edge of the galvanometer spot.

[0087] Correspondingly, step S30 can include step B41:

[0088] Step B41, according to the position information of the reference straight line and the position information of the target edge of the galvanometer spot, calculating to obtain the beam swing angle deviation of the laser welding gun.

[0089] In a feasible implementation, the "extracting the contour of the galvanometer spot in the gray image" in step A32 and / or step A42 can include steps C11-C12:

[0090] Step C11, extracting the contour of the galvanometer spot in the gray image.

[0091] Step C12, according to the contour of the galvanometer spot, calculating to obtain the corrected contour of the galvanometer spot, wherein the corrected contour is the minimum circumscribed rectangle of the contour of the galvanometer spot.

[0092] Correspondingly, the "calculating to obtain the length pixel amount of the galvanometer spot" in step A32 can include: calculating to obtain the length pixel amount of the galvanometer spot according to the corrected contour of the galvanometer spot, and the "calculating to obtain the position information of the target edge of the galvanometer spot" in step A42 can include: calculating to obtain the position information of the target edge of the galvanometer spot according to the corrected contour of the galvanometer spot.

[0093] It should be noted that the formation principle of the galvanometer spot is that the test light beam generated by the laser is incident on the reflecting mirror of the galvanometer, the galvanometer is composed of two reflecting mirrors perpendicular to each other, and scans along the X and Y axes respectively, the reflecting angle of the reflecting mirror is controlled to make the laser beam deflect, and then focused through the focusing system (such as f-θ lens, etc.), and the galvanometer spot is generated in the attenuation imaging area. The contour of the galvanometer spot is usually non-smooth, and if the contour is directly used to calculate the length pixel amount and the position of the galvanometer spot, the calculation result may be distorted. The measurement method in the embodiment extracts the contour of the galvanometer spot in the gray image to obtain an initial contour, and then calculates the minimum circumscribed rectangle of the initial contour to obtain the corrected contour of the galvanometer spot. It can be understood that calculating the length pixel amount of the galvanometer spot according to the corrected contour can improve the calculation accuracy of the length pixel amount, and further improve the calculation accuracy of the swing width. In addition, calculating the position information of the target edge of the galvanometer spot according to the corrected contour can improve the calculation accuracy of the position information, and further improve the calculation accuracy of the beam swing angle deviation.

[0094] In one feasible implementation, prior to step S10, the method for measuring the light emission quality of the laser welding gun may further include step S01:

[0095] Step S01: Illuminate the imaging plate with a light source at a target power, wherein the target power satisfies the following constraints:

[0096]

[0097] Where n is the target grayscale ratio, P is the target power, K1 is the reflection coefficient of the attenuation imaging region, and L1 is the brightness of the beam imaging.

[0098] It should be noted that the target grayscale ratio is defined as the grayscale ratio of the beam imaging and attenuation imaging regions when they can be accurately segmented. Noise will occur when the grayscale ratio of the beam imaging and attenuation imaging regions is less than the target grayscale ratio. By configuring the light source, the overall brightness of the imaging plate can be increased even in poor measurement environments, resulting in a clear image of the imaging plate. By illuminating the imaging plate with the target power using the light source, the beam imaging and attenuation imaging regions in the imaging plate image achieve the target grayscale ratio, effectively improving the accuracy of subsequent image recognition. Notably, the same imaging plate can be used to measure the output quality of various types of laser welding torches, greatly improving measurement efficiency and reducing measurement costs.

[0099] In one feasible implementation, the reflectance coefficient of the imaging patch satisfies the following constraint:

[0100]

[0101] Where n is the target grayscale ratio, P is the target power, K2 is the reflectance coefficient of the background area, and K3 is the reflectance coefficient of the reference area.

[0102] In one specific implementation, refer to Figure 3 The schematic diagram of the component positions shown indicates that the testing device for measuring the light output quality of this laser welding gun may include an imaging plate, a light source, and a camera arranged in sequence. The light source illuminates the side of the imaging plate facing the camera. Preferably, the light source is a ring light source, and the camera can capture a complete image of the imaging plate through the central through-hole of the ring light source.

[0103] In one feasible implementation, step A11, "extracting the outline of the reference circle in the grayscale image," may include steps A111-A112:

[0104] Step A111: Identify the edge points of the reference circle in the grayscale image;

[0105] Step A112: Fit the edge points to a circle to obtain the outline of the reference circle.

[0106] In a feasible implementation, after step S30, the method for measuring the light output quality of the laser welding gun can further include step S40:

[0107] Step S40: according to the target measurement parameter, an evaluation value of the light output quality of the laser welding gun is calculated.

[0108] In a specific implementation, the evaluation value of the light output quality of the laser welding gun is calculated by using the following formula:

[0109]

[0110] In the formula, K is the evaluation value of the light output quality of the laser welding gun, S1, S2, S3 and S4 are preset weight coefficients, k1 is a normalized value of the centering deviation physical quantity, k2 is a normalized value of the swing width, k3 is a normalized value of the beam swing angle deviation, and k4 is a normalized value of the jumping value.

[0111]

[0112] In the formula, e is a natural constant, dc is a centering deviation physical quantity, ql is a swing width, θ is a beam swing angle deviation, dt is a jumping value, and through the evaluation of different weights of S1-S4, the evaluation value K of the light output quality of the laser welding gun can be obtained, and the greater the value is, the more it tends to the target quality.

[0113] The above are only some embodiments of the present application, and do not limit the protection scope of the present application, and any equivalent structural transformation made by using the content of the present application specification and drawings, or direct / indirect application in other related technical fields is included in the protection scope of the present application.

Claims

1. A method of measuring the light output quality of a laser welding torch, characterized in that, The method comprises: In the process of generating a light beam image by irradiating a decay imaging area of a test light beam of a laser welding gun on an imaging sheet, an imaging sheet image is obtained by photographing the imaging sheet by using a camera, wherein the imaging sheet further comprises a background area and a reference object area, and a reference circle and a reference straight line are arranged in the reference object area, and a center of the reference circle is located on a central axis of a welding nozzle of the laser welding gun; The imaging sheet image is converted into a gray scale image; An outline of the reference circle in the gray scale image is extracted, and a pixel size of the reference circle is calculated and obtained; According to the pixel size and the physical size of the reference circle, a conversion coefficient between a pixel amount and a physical amount of the reference object is calculated and obtained; According to the outline of the reference circle, center position information of the reference circle is calculated and obtained; When the light beam image is a static spot, an outline of the static spot is recognized, and focus position information of the static spot is calculated and obtained; According to the center position information of the reference circle and the focus position information of the static spot, a pixel amount of a centering deviation between a light beam focus and the welding nozzle is calculated and obtained; According to the pixel amount of the centering deviation and the conversion coefficient, a physical amount of the centering deviation between the light beam focus and the welding nozzle is calculated and obtained; A reference straight line in the gray scale image is extracted, and position information of the reference straight line is calculated and obtained; When the light beam image is a galvanometer mirror spot, an outline of the galvanometer mirror spot in the gray scale image is extracted, and position information of a target edge of the galvanometer mirror spot is calculated and obtained; According to the position information of the reference straight line and the position information of the target edge of the galvanometer mirror spot, a light beam swing angle deviation of the laser welding gun is calculated and obtained.

2. The method of claim 1, wherein the laser welding gun light output quality is measured by: The method further comprises: When the light beam image is a galvanometer mirror spot, an outline of the galvanometer mirror spot in the gray scale image is extracted, and a length pixel amount of the galvanometer mirror spot is calculated and obtained; According to the length pixel amount of the galvanometer mirror spot and the conversion coefficient, a swing width of the galvanometer mirror spot is calculated and obtained.

3. The method of claim 2, wherein the step of measuring the output quality of the laser welding torch further comprises the step of: After the step of calculating and obtaining the swing width of the galvanometer mirror spot according to the length pixel amount of the galvanometer mirror spot and the conversion coefficient, the method further comprises: According to the swing widths of the galvanometer mirror spots in two continuous periods, a jumping value of the laser welding gun is calculated and obtained.

4. The method of claim 1, wherein the laser welding gun light output quality is measured by: The extraction of the outline of the galvanometer mirror spot in the gray scale image comprises: According to the outline of the galvanometer mirror spot, a corrected outline of the galvanometer mirror spot is calculated and obtained, and the position information of the target edge of the galvanometer mirror spot is calculated and obtained according to the corrected outline of the galvanometer mirror spot, wherein the corrected outline is a minimum circumscribed rectangle of the outline of the galvanometer mirror spot.

5. The method of claim 1, wherein the laser welding gun light output quality is measured by: Before the step of obtaining the imaging sheet image by photographing the imaging sheet by using the camera, the method further comprises: The imaging sheet is irradiated by using a light source at a target power, and the target power satisfies the following constraint condition: Wherein, n is a target gray scale ratio, P is the target power, K1 is a reflection coefficient of the decay imaging area, and L1 is a brightness of the light beam image.

6. The method of claim 1, wherein, The extraction of the outline of the reference circle in the gray scale image comprises: Edge points of the reference circle in the gray scale image are recognized; The edge points are fitted into a circular shape to obtain the outline of the reference circle.

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