Visual weld joint detection system for automobile part welding

Abstract

The invention relates to a visual welding seam detection system for automobile part welding, and belongs to the technical field of welding seam detection in the automobile manufacturing industry, the visual welding seam detection system comprises a scanning sensor, a control module, an identification module and a database, the scanning sensor is used for scanning each welding seam surface of a part and uploading scanning data to the control module; the recognition module is used for recognizing the type of a to-be-detected part and reporting the type to the control module, the control module recognizes all welding seams according to the type of the part, the control module inputs the structural strength requirements of all the part parts in advance, and the detection module detects the welding seams according to the structural strength requirements of all the part parts, the reflectivity of the surface of the part and ambient light parameters. The judgment standard of each welding seam is adjusted, and the control module judges whether the welding seams are qualified or not according to the adjusted judgment standard after receiving the scanning data of the welding seams; the working efficiency and the finished product quality are ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of weld detection in automobile manufacturing industry, and in particular relates to a visual weld detection system for welding automobile parts. Background Art

[0002] A visual weld inspection system is a system that uses image processing and computer vision technology to automatically inspect and evaluate weld joints and welds. This system uses a camera or other image sensor to obtain images of the weld and uses analysis algorithms to determine the quality, integrity and conformity of the weld.

[0003] At present, the commonly used method is to inspect the weld with human eyes, classify the objects to be tested according to the inspection situation, and then proceed to the next step. When the operation is discontinuous, the volume and weight of the workpiece are too large, and errors occur in manual processing, the work of the front and rear stations is affected, thereby reducing production efficiency. In addition, the operation accuracy mainly depends on the personal working state of the operator. Therefore, it is urgent to provide a weld surface visual recognition system with higher automation and higher accuracy. To this end, Chinese patent application CN118641542A discloses a weld visual inspection system and a control method thereof. The system includes a workpiece conveying component, a frame, a first position sensor for identifying the position of the weld to be detected, a second position sensor, and a plurality of cameras for photographing the weld to be detected, and also includes a main controller. In the process of the workpiece conveying component conveying the workpiece to be tested, the main controller receives the first recognition signal of the first position sensor. When the first recognition signal indicates that the weld to be detected is identified, the main controller controls each camera to shoot an image including the weld to be detected; the main controller analyzes the image to determine whether the shape of the weld to be detected is abnormal; the main controller is also used to receive the second recognition signal of the second position sensor. When the second recognition signal indicates that the weld to be detected is identified, the main controller controls each camera to close. Through the above solution of the present invention, human resources are released, production efficiency is significantly improved, and errors in manual weld positioning are effectively avoided.

[0004] However, in the field of automobile production, automobile parts are usually more complicated. The functions of various parts that need to be welded are different, and the required structural strengths are different. The judgment standards for whether the welds in different parts are qualified are different. For parts that require stronger structural strength, the welds are strictly judged to ensure the quality of the finished product. For parts that require weaker structural strength, there is no need to strictly judge the welds to ensure operating efficiency. For this reason, a visual weld inspection system for automobile parts welding is needed that takes into account both operating efficiency and finished product quality. Summary of the invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a visual weld inspection system for automobile parts welding, which has the characteristics of ensuring both operation efficiency and finished product quality.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A visual weld inspection system for automobile parts welding that ensures both work efficiency and finished product quality, comprising a scanning sensor, a control module, a recognition module and a database, wherein the scanning sensor is used to scan the surface of each weld of the part and upload the scanned data to the control module;

[0008] The identification module is used to identify the type of parts to be inspected and report to the control module. The control module identifies each weld according to the part type. The control module pre-inputs the structural strength requirements of each part and adjusts the judgment criteria of each weld according to the structural strength requirements of each part. After receiving the scanning data of several welds, the control module judges whether the several welds are qualified according to the adjusted judgment criteria.

[0009] As a preferred technical solution of the present invention, it also includes a database, and the database is used to store the structural strength requirements of various parts.

[0010] As a preferred technical solution of the present invention, the control module is pre-input with the structural strength requirements X1, X2, ..., Xn of each part and the standard structural strength requirement X0. When the control module determines whether the weld with serial number n is qualified, the standard range is reduced by A1 times, wherein A1=Xn / X0×c+d, and c and d are pre-input constants.

[0011] As a preferred technical solution of the present invention, it also includes an input panel, which is used to input the values ​​of X1, X2, ..., Xn and X0, and is used to display the judgment results of whether several welds are qualified.

[0012] As a preferred technical solution of the present invention, it also includes an ambient light detection module, which is used to detect the ambient light around the scanning sensor and upload it to the control module. The control module determines whether the ambient light exceeds a threshold and narrows the standard range when the threshold is exceeded.

[0013] As a preferred technical solution of the present invention, the ambient light detection module is used to detect the ambient light around the scanning sensor and upload the light intensity data L to the control module, and the control module reduces the standard range by A2 times, where A2 = L / L0×e, L0 and e are pre-input constants.

[0014] As a preferred technical solution of the present invention, it also includes a reflectivity sensor, which is used to detect the reflectivity of the scanning area of ​​the scanning sensor and upload it to the control module. The control module determines whether the reflectivity exceeds a threshold and expands the standard range when the reflectivity exceeds the threshold.

[0015] As a preferred technical solution of the present invention, the reflectivity sensor is used to detect the reflectivity F of the scanning area of ​​the scanning sensor and upload it to the control module, which expands the standard range by A3 times, where A3 = F0 / F×y, F0 and y are pre-input constants.

[0016] As a preferred technical solution of the present invention, the control module adjusts the judgment standard of the scanning sensor to A1×A2 / A3 times the standard range. The control module is used to determine whether A1×A2 / A3 is less than a preset threshold, and executes a manual review procedure when the judgment result is yes.

[0017] As a preferred technical solution of the present invention, the input panel is used to display the coupling relationship curve between the Xn / X0 ratio corresponding to each weld position and the ambient light L and reflectivity F, and the curve is automatically generated according to the statistical law of the historical qualified weld data of the part.

[0018] The beneficial effects of the present invention are:

[0019] (1) The identification module is used to identify the type of parts to be inspected and report to the control module. The control module identifies each weld according to the part type. The control module pre-inputs the structural strength requirements of each part and adjusts the judgment standard of each weld according to the structural strength requirements of each part. After receiving the scanning data of several welds, the control module judges whether several welds are qualified according to the adjusted judgment standard, so that for the parts that require stronger structural strength, the welds are strictly judged to ensure the quality of the finished product. For the parts that require weaker structural strength, there is no need to strictly judge the welds to ensure the operation efficiency;

[0020] (2) An ambient light detection module is set up to scan the ambient light around the sensor and upload it to the control module, and the control module determines whether the ambient light exceeds the threshold. When the ambient light is strong and interferes with the laser-based detection results, the standard range is narrowed, and the probability of judging an unqualified weld as qualified due to the influence of ambient light is reduced, thereby improving the accuracy of weld detection.

[0021] (3) A reflectivity sensor is set to detect the reflectivity of the scanning area of ​​the scanning sensor and upload it to the control module, and the control module determines whether the reflectivity exceeds the threshold value. When the reflectivity exceeds the threshold value, the standard range is expanded. When the reflectivity is weak and interferes with the laser-based detection results, the standard range is narrowed, thereby reducing the probability of judging an unqualified weld as qualified due to the influence of reflectivity, thereby further improving the accuracy of weld detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0023] Figure 1 It is a schematic diagram of the overall architecture of the system of the present invention;

[0024] Figure 2 This is a schematic diagram of the working principle of the scanning sensor of the present invention;

[0025] Figure 3 It is a schematic diagram of the flow of adjusting the weld seam judgment standard by the control module of the present invention;

[0026] Figure 4 It is a schematic diagram of the function of the ambient light detection module and the reflectivity sensor of the present invention;

[0027] Figure 5 The figure is a schematic diagram of the working process of the ambient light detection module and the reflectivity sensor of the present invention. DETAILED DESCRIPTION

[0028] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0029] refer to Figure 1-Figure 5 , a visual weld inspection system for welding automobile parts, including a scanning sensor, a control module, a recognition module and a database, wherein the scanning sensor is used to scan the surface of each weld of the part and upload the scanned data to the control module;

[0030] like Figure 1 As shown, a core component of a visual weld inspection system for automobile parts welding includes a scanning sensor, a control module, a recognition module, a database, an input panel, an ambient light detection module, and a reflectivity sensor. The scanning sensor includes at least a camera and a laser. The components are interconnected through data lines or signal lines to form a complete inspection system.

[0031] like Figure 2 As shown in the figure, the working principle of the scanning sensor is as follows: the laser emits light, which passes through a circular lens to form a line laser and is projected onto the surface of the weld to be inspected. The camera is installed at a certain angle to the laser to capture the reflected light of the line laser on the weld surface. The different heights of the weld surface will cause the position of the reflected light in the camera's field of view to change, thereby achieving the measurement of the three-dimensional profile;

[0032] Specifically, the scanning sensor includes a camera and a laser, both of which are electrically connected to the control module. According to the actual application scenario, the scanning sensor including the camera and the laser is optimized for a specific processor speed and welding state. At the same time, the control module also includes an image processing module. The sensor unit works together with the image processing module. This mode system uses previously established inspection standards to evaluate welding quality.

[0033] The measurement principle using a laser is as follows: the light source used in the measurement includes a laser light source with a circular lens. In this embodiment, the laser light source is a line laser. The camera and the light source form a certain angle. There is a ray of light in the field of view of the camera that illuminates the scanned object. The light of this line will be displaced and distorted to propel objects at different heights on this line. The angle between the camera and the light source, that is, the triangulation angle, determines the displacement and distortion of the light in the height direction. The larger the angle, the greater the magnification. Since the triangulation angle is known, the three-dimensional point on the object can be inferred from the position of the light, thereby inferring the contour of the object; at the same time, the control module pre-inputs a standard size range of the contour, that is, the standard range, and then compares the size of the object contour with the standard size. The qualified or unqualified is determined based on whether the detected weld contour size falls within the standard range. When the weld contour size falls within the standard range, it is determined to be qualified, otherwise it is unqualified.

[0034] At the same time, the control module pre-inputs possible weld shapes, possible welding processes of fillet welds or other weld shapes, such as metal inert gas welding (MIG) / metal active gas welding (MAG) welds, laser welds, steel-aluminum dissimilar material welds, etc., as well as weld length, weld height, holes, pores, hole spots, edge cuts, weld positions, weld volumes, weld lengths, protrusions, depressions, weld thickness, symmetry, unfilled end craters and others of various welds;

[0035] In this embodiment, the detection speed is 6-50m / min, the scanning speed (beam frequency) is 345-2805 Hz, the resolution is 10 microns, the laser class of the laser device (in accordance with EN 60825-1:2008 standard): Class 3B (corresponding to sensor model 103490) or Class 2 (corresponding to sensor model 106719); laser output power ≤ 40mW; safety distance (NOHD): 1400mm;

[0036] In the field of automobile production, automobile parts are usually more complicated. The functions of the parts that need to be welded are different, and the required structural strength is different. The judgment standards for whether the welds of different parts are qualified are different. For the parts that require stronger structural strength, the welds are strictly judged to ensure the quality of the finished product. For the parts that require weaker structural strength, there is no need to strictly judge the welds to ensure the operation efficiency.

[0037] To this end, the identification module is used to identify the type of the part to be detected and report to the control module. The control module identifies each weld according to the part type. The control module inputs the structural strength requirements of each part in advance and adjusts the judgment standard of each weld according to the structural strength requirements of each part. After receiving the scanning data of several welds, the control module judges whether several welds are qualified according to the adjusted judgment standard.

[0038] like Figure 3 As shown, the control module adjusts the weld judgment criteria according to the part type, weld position and structural strength requirements. First, the recognition module identifies the part type and reports it to the control module; then, the control module identifies each weld according to the part type, and adjusts the weld judgment criteria according to the pre-input structural strength requirements of each part; finally, the control module makes a qualification judgment on the weld scan data according to the adjusted judgment criteria;

[0039] Specifically, after reading each part, the control module marks a serial number for each area where a potential weld may be located. The serial number is a natural number 1, 2, ..., n that increases in a single point. At the same time, the control module adjusts the order in which different parts of the current automobile part pass through the scanning sensor, and then adjusts the order in which different welds pass through the scanning sensor. The control module adjusts the order in which different parts of the current automobile part pass through the scanning sensor to ensure that the welds pass through the scanning sensor in the ascending order of the weld numbers in the database.

[0040] At this time, the first weld scanning data received by the control module is weld No. 1, the second weld scanning data received is weld No. 2, and so on;

[0041] The control module can now know which weld the current scan data is. When judging whether a weld with a certain number meets the standard, the control module synchronously calls the structural strength requirement of the position corresponding to the number, and then synchronously adjusts the judgment standard of the weld when judging welds at different positions.

[0042] Specifically, the control module pre-inputs the structural strength requirements X1, X2, ..., Xn of each part and the standard structural strength requirement X0. When the control module determines whether the weld with serial number n is qualified, the standard range is reduced by A1 times, where A1=Xn / X0×c+d, and c and d are pre-input constants;

[0043] When the structural strength requirement Xn of a certain part is large, it means that a small weld shape deviation has a greater probability of causing a decrease in structural strength, and the standard range needs to be narrowed. At this time, the value of A1=Xn / X0×c+d is large, the reduction multiple is large, and the weld inspection result is more likely to fall outside the judgment standard and be judged as unqualified. For the parts that require stronger structural strength, strict judgment is made on the welds;

[0044] When the structural strength requirement Xn of a certain part is small, the influence of weld shape deviation on the shape is small, and there is no need to narrow the judgment standard too narrowly, so as to affect production efficiency. At this time, the value of A1=Xn / X0×c+d is small, the reduction factor is small, and the probability that the weld inspection result can fall outside the judgment standard and be judged as unqualified is small, thus completing the relaxation of the weld judgment standard for parts with weaker structural strength.

[0045] The identification module is used to identify the type of parts to be inspected and report to the control module. The control module identifies each weld according to the part type. The control module pre-inputs the structural strength requirements of each part and adjusts the judgment criteria of each weld according to the structural strength requirements of each part. After receiving the scanning data of several welds, the control module judges whether several welds are qualified according to the adjusted judgment criteria, so that for parts that require stronger structural strength, the welds are strictly judged to ensure the quality of the finished product. For parts that require weaker structural strength, there is no need to strictly judge the welds to ensure work efficiency.

[0046] In order to facilitate the data storage of the types of parts and the structural strength requirements of various parts, a database is also included, and the database is used to store the structural strength requirements of various parts.

[0047] In order to facilitate the input of the values ​​of X1, X2, ..., Xn and X0, an input panel is also included. The input panel is used to input the values ​​of X1, X2, ..., Xn and X0, and to display the judgment results of whether several welds are qualified.

[0048] In the above process, the judgment of whether the threshold value is exceeded will be affected by the ambient light. When the ambient light is strong, it will interfere with the detection result based on the laser, resulting in the judgment of unqualified welds as qualified. In order to reduce the probability of judging unqualified welds as qualified due to the influence of ambient light, an ambient light detection module is also included. The ambient light detection module is used to detect the ambient light around the scanning sensor and upload it to the control module. The control module determines whether the ambient light exceeds the threshold value and narrows the standard range when the threshold value is exceeded.

[0049] like Figure 4-5As shown in the figure, the role of the ambient light detection module and the reflectivity sensor in the visual weld inspection system: the ambient light detection module is used to detect the ambient light intensity around the scanning sensor and upload the data to the control module, so as to reduce the judgment standard when the ambient light is too strong and improve the detection accuracy. The reflectivity sensor is used to detect the reflectivity of the scanning area and also upload the data to the control module, so as to reduce the judgment standard when the reflectivity is high and improve the detection standard; expand the judgment standard when the reflectivity is low and reduce the misjudgment rate;

[0050] Specifically, the ambient light detection module is used to detect the ambient light around the scanning sensor and upload the light intensity data L to the control module, and the control module reduces the standard range by A2 times, where A2 = L / L0×e, L0 and e are pre-input constants;

[0051] When the ambient light is strong, it will interfere with the laser-based detection results. There is a probability that an unqualified weld will be judged as qualified due to the influence of the ambient light. The judgment standard needs to be tightened. At this time, the value of A2=L / L0×e is large, and the tightening of the judgment standard when the light intensity is strong is completed;

[0052] When the ambient light is weak, the interference to the laser-based detection results is small, and the probability of judging an unqualified weld as qualified is low, so there is no need to tighten the judgment standard. At this time, the value of A2=L / L0×e is small, and the judgment standard is not tightened to a large extent when the light intensity is strong;

[0053] By setting up an ambient light detection module to collect the ambient light around the scanning sensor and upload it to the control module, the control module determines whether the ambient light exceeds the threshold. When the ambient light is strong and interferes with the laser-based detection results, the standard range is narrowed, reducing the probability of judging unqualified welds as qualified due to the influence of ambient light, thereby improving the detection accuracy.

[0054] In the above process, when the reflectivity of the material where the weld is located is higher, more light information will be reflected to the camera. At this time, the reflected light received by the camera can represent the actual surface shape to a greater extent. At this time, the probability of deviation of the laser-based detection results is relatively small, and it is necessary to narrow the standard range and improve the judgment standard. For this purpose, a reflectivity sensor is also included. The reflectivity sensor is used to detect the reflectivity of the scanning area scanned by the scanning sensor and upload it to the control module. The control module determines whether the reflectivity exceeds the threshold and narrows the standard range when the reflectivity exceeds the threshold.

[0055] Specifically, the reflectivity sensor is used to detect the reflectivity F of the scanning area of ​​the scanning sensor and upload it to the control module, and the control module expands the standard range by A3 times, where A3 = F0 / F×y, F0 and y are pre-input constants;

[0056] When the reflectivity is strong, it means that the probability of deviation of the laser-based detection result is small, and the standard range needs to be increased. At this time, the value of A3=F0 / F×y is small, less than 1. When the control module expands the standard range by A3 times, the reflectivity is strong, the standard range is reduced, and the judgment standard is improved;

[0057] When the reflectivity is weak, it means that the probability of deviation of the laser-based detection result is high, and the standard range needs to be expanded to prevent inaccurate detection. At this time, the value of A3=F0 / F×y is large, greater than 1. When the control module expands the standard range by A3 times, the expansion of the standard range is completed when the reflectivity is strong;

[0058] By narrowing the standard range when the reflectivity is strong and expanding the standard range when the reflectivity is weak, the reflected light received by the camera can represent the actual surface shape to a greater extent. When the probability of deviation of the laser-based detection result is small, the judgment standard is improved, and when the probability of deviation of the laser-based detection result is large, the judgment standard is lowered to reduce the misjudgment rate.

[0059] Furthermore, the control module comprehensively adjusts the standard range through the composite adjustment coefficient A. On the basis of maintaining the original three adjustment parameters (structural strength, ambient light and reflectivity), a composite algorithm is established to achieve multi-factor collaborative control, and a safety mechanism is set to avoid over-automation. Specifically, the control module adjusts the judgment standard of the scanning sensor to A1×A2 / A3 times the standard range;

[0060] When the composite adjustment coefficient A1×A2 / A3 is less than the preset threshold, it means that the judgment range caused by the automatic adjustment is too small, and the role of production guidance is limited. At this time, manual correction is required. Therefore, when the control module determines that A1×A2 / A3 is less than the preset threshold, the manual review mechanism is triggered. Specifically, when the manual review mechanism is triggered, the control module sends a corresponding sound and light signal and displays a review prompt message on the input panel;

[0061] Furthermore, it also includes an input panel. The input panel has a dynamic parameter configuration interface, which extends the dimension of human-computer interaction, visualizes the parameter adjustment process and associates it with historical data. It can display and adjust the coupling relationship curve of the Xn / X0 ratio corresponding to each weld position and the ambient light L and reflectivity F in real time. The curve is automatically generated according to the statistical law of the historical qualified weld data of the part.

[0062] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A visual weld inspection system for automobile parts welding, characterized in that: It includes a scanning sensor, a control module, an identification module and a database, wherein the scanning sensor is used to scan the surface of each weld of the part and upload the scanning data to the control module; The identification module is used to identify the type of parts to be inspected and report to the control module. The control module identifies each weld according to the part type. The control module pre-inputs the structural strength requirements of each part and adjusts the judgment criteria of each weld according to the structural strength requirements of each part. After receiving the scanning data of several welds, the control module judges whether the several welds are qualified according to the adjusted judgment criteria.

2. A visual weld inspection system for automobile parts welding according to claim 1, characterized in that: Also included is a database for storing structural strength requirements of various parts.

3. A visual weld inspection system for automobile parts welding according to claim 1, characterized in that: The control module is pre-input with the structural strength requirements X1, X2, ..., Xn of each part and the standard structural strength requirement X0. When the control module determines whether the weld with serial number n is qualified, the standard range is reduced by A1 times, where A1=Xn / X0×c+d, and c and d are pre-input constants.

4. The visual weld inspection system for automobile parts welding according to claim 1 is characterized in that: It also includes an input panel, which is used to input the values ​​of X1, X2, ..., Xn and X0, and is used to display the judgment results of whether several welds are qualified.

5. The visual weld inspection system for automobile parts welding according to claim 1 is characterized in that: It also includes an ambient light detection module, which is used to detect the ambient light around the scanning sensor and upload it to the control module. The control module determines whether the ambient light exceeds a threshold and narrows the standard range when the threshold is exceeded.

6. A visual weld inspection system for automobile parts welding according to claim 5, characterized in that: The ambient light detection module is used to detect the ambient light around the scanning sensor and upload the light intensity data L to the control module, and the control module reduces the standard range by A2 times, where A2=L / L0×e, L0 and e are pre-input constants.

7. A visual weld inspection system for automobile parts welding according to claim 5, characterized in that: It also includes a reflectivity sensor, which is used to detect the reflectivity of the scanning area of ​​the scanning sensor and upload it to the control module. The control module determines whether the reflectivity exceeds a threshold value and expands the standard range when the reflectivity exceeds the threshold value.

8. A visual weld inspection system for automobile parts welding according to claim 7, characterized in that: The reflectivity sensor is used to detect the reflectivity F of the scanning area of ​​the scanning sensor and upload it to the control module, and the control module expands the standard range by A3 times, where A3=F0 / F×y, F0 and y are pre-input constants.

9. A visual weld inspection system for automobile parts welding according to claim 8, characterized in that: The control module adjusts the judgment standard of the scanning sensor to A1×A2 / A3 times the standard range. The control module is used to judge whether A1×A2 / A3 is less than a preset threshold, and executes a manual review procedure when the judgment result is yes.

10. A visual weld inspection system for automobile parts welding according to claim 9, characterized in that: It also includes an input panel, which is used to display the coupling relationship curve between the Xn / X0 ratio corresponding to each weld position and the ambient light L and reflectivity F. The curve is automatically generated according to the statistical law of the historical qualified weld data of the part.

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