Welding inspection device, welding inspection method, and welding inspection system

Abstract

To provide a welding inspection apparatus, a welding inspection method, and a welding inspection system that can determine a relative position relationship of spots with low cost and accuracy in an inspection of spot positions of spot welding.SOLUTION: A welding inspection apparatus according to the present invention for inspecting a spot position of spot welding includes: an image acquisition unit which acquires a photographed image obtained by imaging a workpiece containing multiple welding spots; a detection unit which detects a reference position from within an area containing an inspection spot of the photographed image; a calculation unit which calculates a distance between the detected reference position and the inspection spot; and a determination unit which determines whether or not the distance is within a prescribed range.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a welding inspection apparatus, a welding inspection method, and a welding inspection system that perform spot welding on a workpiece such as an automobile body and inspect the position of the spot weld formed on the workpiece.

Background Art

[0002] In the manufacturing process of automobiles, spot welding is performed on various vehicle body parts using a welding robot. After spot welding, it is inspected whether the position of the spot weld formed on the workpiece is appropriate according to a pre-prepared design drawing.

[0003] Conventionally, this inspection has been performed as a visual inspection in which an operator visually checks the position and number of the spots after spot welding by comparing the body on which the spot welding has been performed with its design drawing. However, such inspection work has been very time-consuming and labor-intensive because the number of spots of spot welding is about 6,000 on one automobile. Further, due to the judgment by a human eye of the operator, the inspection accuracy could not be said to be high.

[0004] Therefore, in order to solve the problems of the inspection work by visual inspection, an inspection system that determines the spots of spot welding using a camera has been considered. For example, in the system described in Patent Document 1, an indicator indicating the spots on the vehicle body part and a camera arranged to face an identification part provided on the indicator are used. In this system, the vehicle body part is photographed by the camera, and the position of the spot is calculated as three-dimensional information based on the imaging signal from the camera. Then, in this system, it is determined whether the detected position of the spot is at the correct position by comparing the calculated three-dimensional position of the spot with the pre-registered three-dimensional position of the spot.

[0005] The system described in Patent Document 2 extracts dots from both 3D image data obtained by photographing vehicle body parts with a camera and 3D design data. The system then determines whether the positions of the extracted dots are appropriate based on the relationship between the dots in the 3D image data and the 3D design data. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2007-152371 [Patent Document 2] Japanese Patent Publication No. 2017-144454 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, the technology described in Patent Document 1 requires the preparation of an indicator to point to the dotted area. The process of calculating the 3D position of the dotted area in contact with the indicator from the position of the light-emitting element provided on the indicator, based on the camera's imaging signal, is complicated and the inspection cost is high. Furthermore, the 3D position of the dotted area is compared with the 3D position of the design data to determine whether the detected dotted area is within an acceptable range.

[0008] Furthermore, the technology described in Patent Document 2 requires the preparation of a 3D camera for acquisition of 3D image data, which is costly. In addition, the appropriateness of the extracted weld points is determined by whether the positional deviation of the weld points in the 3D image data relative to the weld points in the 3D design data falls below a predetermined tolerance value. Therefore, even if the position of the inspected weld points is below the tolerance value, there is a possibility that sufficient welding strength may not be obtained for the entire welded area.

[0009] The present invention was made to solve these problems, and aims to provide a welding inspection device, a welding inspection method, and a welding inspection system that can determine the relative positional relationship of spot welds at low cost and with high accuracy in inspecting the position of spot welds. [Means for solving the problem]

[0010] The inspection device according to the present invention is a welding inspection device for inspecting the position of spot welds, and comprises an image acquisition unit that acquires a captured image of a workpiece including multiple welding points, a detection unit that detects a reference position from within the region of the captured image that includes the inspection points, a calculation unit that calculates the distance between the detected reference position and the inspection points, and a determination unit that determines whether the distance is within a predetermined range. With this configuration, it is possible to determine whether the relationship between the inspection points and the reference position is normal based on the relative positional relationship with the reference position, rather than comparing the inspection points with a design drawing. Since comparison with a 3D design drawing is unnecessary, it can be implemented at low cost.

[0011] Here, the reference position is at least one of the adjacent welding point, the edge of the workpiece, and the R-shaped portion of the workpiece. With this configuration, by using the adjacent welding point, the edge of the workpiece, and the R-shaped portion adjacent to the inspection welding point as reference positions, inspection can be efficiently performed using the welding points and the edge of the workpiece without having to set up a separate reference position.

[0012] Furthermore, the determination unit determines whether the distance between multiple reference positions and the inspection point is within a predetermined range. This configuration allows for higher inspection accuracy of the inspection point compared to when the determination is based on a single reference position.

[0013] Here, within the area of ​​the captured image, if the reference position is at least one of the edges and the rounded corners, the predetermined range is smaller compared to when the reference position is an adjacent dot. When the distance to the inspection dot is calculated using at least one of the edges and rounded corners of the workpiece as the reference position, the calculated distance is often extremely small depending on the shape of the workpiece. Therefore, with this configuration, when at least one of the edges and rounded corners of the workpiece is used as the reference position, the judgment unit can determine the positional deviation more strictly compared to when an adjacent dot is used as the reference position.

[0014] Furthermore, the workpiece has a circular calibration marker, and the calculation unit calculates the distance based on the diameter of the calibration marker, which is at the same angle as the line segment connecting the reference position and the inspection point position. With this configuration, even with a two-dimensional image, the distance can be calculated accurately while taking the shooting angle into consideration.

[0015] The welding inspection method according to the present invention is a welding inspection method for inspecting the position of spot welds, comprising: an image acquisition step of acquiring a photographic image of a workpiece including multiple welding points; a detection step of detecting a reference position from within the region of the photographic image including the inspection points; a calculation step of calculating the distance between the detected reference position and the inspection points; and a determination step of determining whether the distance is within a predetermined range. With this configuration, it is possible to determine whether the relationship between the inspection points and the reference position is normal based on the relative positional relationship with the reference position, rather than comparing the inspection points with a design drawing. Since comparison with a 3D design drawing is unnecessary, it can be implemented at low cost.

[0016] Here, the reference position is at least one of the adjacent welding point, the edge of the workpiece, and the R-shaped portion of the workpiece. With this configuration, by using the adjacent welding point, the edge of the workpiece, and the R-shaped portion adjacent to the inspection welding point as reference positions, inspection can be efficiently performed using the welding points and the edge of the workpiece without having to set up a separate reference position.

[0017] Furthermore, the determination step determines whether the distance between multiple reference points and the inspection point is within a predetermined range. This configuration allows for higher inspection accuracy of the inspection point compared to determining based on a single reference point.

[0018] Here, within the area of ​​the captured image, if the reference position is at least one of the edges and the rounded corners, the predetermined range is smaller compared to when the reference position is an adjacent dot. When the distance to the inspection dot is calculated using at least one of the edges and rounded corners of the workpiece as the reference position, the calculated distance is often extremely small depending on the shape of the workpiece. Therefore, with this configuration, when at least one of the edges and rounded corners of the workpiece is used as the reference position, the judgment unit can determine the positional deviation more strictly compared to when an adjacent dot is used as the reference position.

[0019] Furthermore, the workpiece has a circular calibration marker, and the image acquisition step acquires an image of the workpiece including multiple welding points and the calibration marker. The calculation step calculates the distance based on the diameter of the calibration marker, which is parallel to the line segment connecting the reference position and the inspection point in the captured image. With this configuration, even with a two-dimensional image, the distance can be calculated accurately while taking the shooting angle into consideration.

[0020] The welding inspection system according to the present invention is a welding inspection system for inspecting the hitting positions of spot welds, comprising a photographing device for photographing a workpiece on which a plurality of welding hits have been performed, and a welding inspection device for inspecting the positions of inspection hits based on the photographed image taken by the photographing device. The welding inspection device includes a detection unit for detecting a reference position from within a region including the inspection hits in the photographed image, a calculation unit for calculating the distance between the detected reference position and the inspection hits, and a determination unit for determining whether the distance is within a predetermined range. With such a configuration, it is possible to determine whether the inspection hit position is normal based on the relative positional relationship with adjacent hits or the ends of the workpiece, rather than by comparing with the design drawing at the inspection hit position. Also, it is possible to efficiently perform inspection by using the welding hits and the ends of the workpiece without separately providing a reference position.

[0021] Furthermore, an output device for outputting the inspection result by the determination unit of the welding inspection device is provided, and the output device displays at least one of the distance from the reference position and the determination result of normal or abnormal based on the distance on the photographed image together with the inspection result. With such a configuration, an operator can confirm the inspection result of the inspection hits by visually recognizing the photographed image.

Effects of the Invention

[0022] According to the present invention, it is possible to provide a welding inspection device, a welding inspection device, and a welding inspection system that can determine the relative positional relationship of the hits with high accuracy at low cost in the inspection of the hitting positions of spot welds.

Brief Description of the Drawings

[0023] [Figure 1] It is a schematic configuration diagram of the welding inspection system according to Embodiment 1. [Figure 2] It is a diagram showing a photographed image of a workpiece in the welding inspection system according to Embodiment 1. [Figure 3] It is an example of inspection information stored in the storage unit in the welding inspection system according to Embodiment 1. [Figure 4]This figure illustrates the image processing of the detection unit in the welding inspection system according to Embodiment 1. (a) shows the captured image, and (b) shows a magnified image of the inspection area of ​​the inspection point. [Figure 5] This is a flowchart showing the welding inspection method according to Embodiment 1. [Figure 6] This figure shows the output device displaying the inspection results on a monitor in the welding inspection system according to Embodiment 1. [Modes for carrying out the invention]

[0024] Embodiment 1. Figure 1 is a schematic diagram of the welding inspection system according to this embodiment 1. The welding inspection system 1 is a system that inspects the relative positional relationship of the spot welds applied to a workpiece W, which is a vehicle body part. This welding inspection system 1 consists of an imaging device 10, a welding inspection device 20, and an output device 30.

[0025] The imaging device 10 is an imaging means that photographs the workpiece W, generates a still image, and outputs the captured image. By connecting the imaging device 10 to the welding inspection device 20, it becomes possible to send and receive captured image data with the inspection device 20. The imaging device 10 may be connected to the inspection device 20 when photographing the workpiece W, or it may be separated from the inspection device 20.

[0026] In this embodiment, the imaging device 10 is a camera. This camera is positioned to photograph the entire area of ​​the workpiece W that includes the inspection point P, which is defined as the welding point to be inspected. The imaging device 10 is positioned such that it photographs the workpiece W from the front. However, the imaging device 10 may also be positioned such that it photographs the workpiece W from an oblique angle. In this embodiment, only one imaging device 10 is provided, but multiple imaging devices 10 may be provided.

[0027] Figure 2 shows images of a workpiece captured in a welding inspection system. In this embodiment, the workpiece W is a B-pillar of a vehicle part. The workpiece W has three welding points P1, P2, and P3, which are designated as inspection points P, the welding points to be inspected. Adjacent welding points Q, the end T of the workpiece W, and the R section R are provided around the inspection points P.

[0028] Furthermore, a calibration marker M is attached to the workpiece W, which serves as a reference for calculating the distance L. The calibration marker M is mounted on the same plane adjacent to the inspection point P. The calibration marker M allows for proper calibration even if the positional relationship between the workpiece W and the imaging device is slightly misaligned. In this embodiment, the calibration marker M is a perfect circle with a diameter of 30 mm. The distance on the captured image is calibrated considering the diameter of the calibration marker M. In addition, it is desirable for the calibration marker to be colored so that it can be detected separately from the welding point.

[0029] Returning to Figure 1, the welding inspection device 20 performs a process to inspect the welding points of the workpiece W based on the image of the workpiece W captured by the imaging device 10. The welding inspection device 20 comprises a storage unit 21, an image acquisition unit 22, a detection unit 23, a calculation unit 24, and a determination unit 25. The welding inspection device 20 is a computer composed of a monitor (display unit), a keyboard (input means), a mouse (selection means), a central processing unit (CPU), RAM, and ROM, and realizes the functions of the storage unit 21, image acquisition unit 22, detection unit 23, calculation unit 24, and determination unit 25 by executing a pre-installed program.

[0030] The memory unit 21 stores inspection information, including the inspection area, for each of the multiple welding point locations on the workpiece W. Furthermore, the memory unit 21 stores the inspection point P, which is the welding point to be inspected, the adjacent welding point Q which is the reference position, and the allowable distance between the inspection point P and the end T and R parts R of the workpiece W, in association with each other.

[0031] Figure 3 shows an example of inspection information stored in the memory unit of the welding inspection system. The position information is defined in a virtual Cartesian coordinate system where the lower leftmost point of the workpiece W in the captured image is the origin (0,0), the horizontal direction is the X-axis (horizontal axis), and the vertical direction perpendicular to the X-axis is the Y-axis (vertical axis). In this embodiment, the welding point positions of the workpiece W are determined by the design drawings, and inspection of the welding point can be performed based on the relative positional relationship with the surrounding adjacent welding points Q, and the ends T and R of the workpiece W.

[0032] In the example where the inspection point is P1, the inspection area is within a radius of 30 mm centered on the inspection point position (XP1, YP1), and four reference points are defined: adjacent point Qa1, adjacent point Qb1, end T1, and R1. The positional information for adjacent points Qa1 and Qb1 is the coordinates (XQa1, YQa1) and (XQb1, YQb1), respectively. The distance from the inspection point position (XP1, YP1) is specified to be within a range of a preset standard value of 25 mm with a tolerance of ±3 mm (22 mm to 28 mm). On the other hand, the positional information for end T1 and R1 is the coordinates (XT1, YT1) and (XR1, YR1), respectively. The distance to the inspection dotting point (XP1, YP1) is specified to be within a predetermined standard value of 5 mm and a tolerance of ±1 mm (4 mm to 6 mm).

[0033] In this embodiment, the distance between the inspection point P and the adjacent point Q is smaller in the allowable range (standard value + tolerance) compared to the distance between the inspection point P and the end T and R portion R of the workpiece W. As a result, when the end T and R portion R of the workpiece W are used as the reference position, compared to when the adjacent point Q is used as the reference position, Positional misalignment This allows for a stricter assessment. When spot welding the end T and R sections R of a workpiece W, the distance to the inspection point P is often extremely small, so even slight misalignment can cause end welding defects. On the other hand, spot welding ensures a predetermined distance between welding points to prevent current shunting during welding, allowing for some degree of misalignment between welding points.

[0034] Returning to Figure 1, the image acquisition unit 22 acquires an overall image, including the inspection points P included in the inspection information, after the spot welding of the workpiece W is completed. Specifically, the image acquisition unit 22 starts the image acquisition process when it receives a completion signal from the equipment after the welding is completed. In the image acquisition process, the image acquisition unit 22 outputs a signal to the imaging device 10 requesting it to perform the image capture process of the workpiece W.

[0035] The detection unit 23 detects inspection dots P in the captured image. After identifying the location of the inspection dots, it detects whether any of the following exist within the inspection area: adjacent dots Q, the end T of the workpiece W, or the R portion R. The detection unit 23 is composed of an inference edge computer with an AI-based machine learning image recognition function. For example, an object detection method (R-CNN) may be used for the detection of inspection dots P and adjacent dots Q. The detection unit also uses a pre-trained dot detection model that has learned from images with and without dots to detect whether or not dots exist. For example, an edge detection method (OpenCV) may be used for the detection of the end T of the workpiece W and the R portion R.

[0036] Figure 4 illustrates the image processing of the detection unit in the welding inspection system. (a) shows a captured image, and (b) shows a magnified image of the inspection area r1 of the inspection point P1. The inspection point P1 will be used as an example. Based on the inspection information in the storage unit 21, the detection unit 23 detects the point present at the location information (XP1, YP1) of the inspection point P1 and identifies it as the inspection point P1. After identifying the inspection point P1, the detection unit 23 detects adjacent points Qa1 and Qb1, and the end T1 and R1 of the workpiece W from the inspection area rP1 ≤ 30 mm. In Figure 4(b), as shown by the dashed lines, demarcation lines are extracted along the detected inspection point P1 and adjacent points Qa1 and Qb1. In addition, dashed lines are extracted along the detected end T1 and R1 of the workpiece W.

[0037] The calculation unit 24 calculates the distance L between the inspection point P and the adjacent point Q, the end T of the workpiece W, and the R portion R. The calculation unit 24 calculates the position coordinates of the inspection point P, the adjacent point Q, the end T of the workpiece W, and the R portion R detected by the detection unit 23. The distance L1 between the inspection point P and the adjacent point Q is calculated from the position coordinates of the center points of each point. The distance L2 between the inspection point P and the end T of the workpiece W and the R portion R is calculated from the position coordinates of the center point of the inspection point P to the shortest distance from the line of the end T and R portion R detected by the edge detection method. Here, the calculation unit 24 calculates the distance between the two points by converting the distance in 1-pixel units of the calibration marker M parallel to the line connecting the two points into the distance between the two points.

[0038] The determination unit 25 determines whether the distance L is within a predetermined range. The predetermined range is an allowable range that takes into account the tolerances that can be allowed with respect to the standard value. If the distance L is within the allowable range, the determination unit 25 determines that the inspection dot position is normal. If the distance L is outside the allowable range, the determination unit 25 determines that the inspection dot position is abnormal and performs abnormality correction. If the inspection area includes multiple adjacent dots Q, the end T and R portion R of the workpiece W, the determination unit 25 determines whether the distance to each adjacent dot Q, the end T and R portion R of the workpiece is within the allowable range, and determines that the inspection dot position is normal if all distances are within the allowable range.

[0039] The output device 30 consists of at least one of the following: a monitor that outputs data by display, a speaker that outputs data by sound, and a printer that outputs data by printing.

[0040] This invention describes a welding inspection method using a welding inspection system 1 that inspects the relative positional relationship of spot welds. Figure 5 is a flowchart of the welding inspection method. The welding inspection method uses the acquired image of the workpiece W to inspect the position of the spot welds. Relative positional relationship This is a method for inspecting welding. The welding inspection method is performed repeatedly during the operation of the spot welding manufacturing process using a welding robot.

[0041] In step S100, the welding inspection device 20 obtains inspection information of the workpiece W from the storage unit 21. Specifically, it obtains the inspection point position, inspection area, reference position, and tolerance range from the inspection information stored in the storage unit 21.

[0042] In step S110, after welding is complete and a completion signal is received from the equipment, the imaging device 10 takes a picture of the entire workpiece W, including the inspection point P.

[0043] In step S120, the image acquisition unit 22 acquires an image of the inspection area of ​​the workpiece W, including the inspection dots P, captured by the imaging device 10. Here, the image acquisition unit 22 may acquire the image by cropping the inspection image of a portion of the inspection area, including the inspection dots P, from the overall image.

[0044] In step S130, the detection unit 23 detects the inspection dot P. After identifying the inspection dot position, it detects whether there is an adjacent dot Q adjacent to the inspection dot P (which is the reference position), the end T of the workpiece W, or the R portion R of the workpiece W within the inspection area.

[0045] In step S140, the calculation unit 24 calculates the distance L between the inspection point P and adjacent points Q, the end T of the workpiece W, and the R portion R. The determination unit 25 then determines whether the distance L is within the acceptable range. Within the inspection area, if the distance L between the inspection point P and all adjacent points Q, the end T of the workpiece W, and the R portion R is within the acceptable range, the inspection point position is determined to be normal. If the distance L between the inspection point P and at least one adjacent point Q, the end T of the workpiece W, and the R portion R is outside the acceptable range, the inspection point position is determined to be abnormal. In step S140, if it is determined to be normal, the process ends; if it is determined to be abnormal, the process proceeds to step S150.

[0046] In step S150, if an abnormality was determined in step S140, an abnormality correction is performed. Examples of abnormality corrections include notifying workers near the welding inspection system or stopping the welding robot. By performing the abnormality correction, the abnormal spot welding position can be immediately recognized, and work can be stopped. This prevents work from continuing in an abnormal spot welding position.

[0047] Figure 6 shows the output device displaying the inspection results on a monitor in the welding inspection system according to Embodiment 1. In this embodiment, the judgment result from the judgment unit 25 is displayed on the monitor. Specifically, along with the inspection result of the dotting position of the inspection dotting point P, the distance between the inspection dotting point P and the adjacent dotting point Q, and the end T and R portion R of the workpiece W are displayed on the captured image of the workpiece W. Furthermore, the judgment result of whether the distance between the inspection dotting point P and the adjacent dotting point Q, and the end T and R portion R of the workpiece W are within a predetermined range is displayed in a way that can be identified by color. In this embodiment, if the result is normal, the distance is displayed in blue, and if it is abnormal, the distance is displayed in red. In addition to displaying the results on the captured image, the inspection results may also be displayed in a table. Alternatively, instead of displaying on the monitor, the results may be printed out as a report.

[0048] The operator or inspector can check the inspection result of the inspection point P by looking at the monitor. In this embodiment, the judgment result is displayed in color on the captured image of the workpiece W, so it is possible to check at a glance whether the inspection point P is applied in the normal welding position. This makes it easy to check the position of the spot welds applied to the workpiece W. Furthermore, the distance between the inspection point P, the adjacent welding point Q, and the end T and R parts R of the workpiece W are displayed, so the location of any abnormalities can be easily identified.

[0049] According to the welding inspection apparatus, welding inspection method, and welding inspection system of this embodiment 1, the inspection point P is identified from the acquired image of the workpiece W based on the inspection information. The position of the inspection point P can then be inspected based on the positional relationship between the inspection point P and adjacent points Q, the end T and R parts R of the workpiece W, which are included in the inspection area surrounding the inspection point P. Here, the inspection area surrounding the inspection point P exists on the same plane as the inspection point P. Therefore, the relative positional relationship of the points can be determined accurately and at low cost without performing the complicated work of comparing the 3D position of the design data with the 3D position of the welding point. Furthermore, since the inspection of the inspection point P is performed automatically by the inspection apparatus 20 and does not rely on visual inspection, the time and effort required for the work can be reduced, and the accuracy of the inspection can be improved.

[0050] According to the welding inspection apparatus, welding inspection method, and welding inspection system of this embodiment 1, the determination unit 25 determines whether the distance between multiple reference positions and the inspection point is within a predetermined range. As a result, when the determination is made based on one reference position, only positional deviation in one direction can be inspected, but when the determination is made based on two reference positions, positional deviation in two directions can be inspected. Furthermore, the more reference positions there are, the more accurately the position of the inspection point can be determined.

[0051] Furthermore, the tolerance range for the distance between the inspection point P and the adjacent point Q is smaller compared to the distance between the inspection point P and the edge R of the workpiece W. As a result, when at least one of the workpiece's edge and R portion is used as the reference position, the judgment unit can determine the positional deviation more strictly than when an adjacent point is used as the reference position.

[0052] In the inspection information shown in Figure 3, only three weld points are subject to inspection, but the inspection is not limited to these; all weld points may be subject to inspection. In this embodiment, the weld point locations that are particularly important for the B-pillar of the vehicle part can be properly inspected.

[0053] Other embodiments. It should be noted that the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention. For example, in the above example, the imaging device 10, the welding inspection device 20, and the output device 30 are provided separately, but the invention is not limited to this, and the imaging device 10, the welding inspection device 20, and the output device 30 may be configured as an integrated unit.

[0054] Furthermore, in the above embodiment, a captured image of the entire workpiece W including the inspection dots P was obtained. However, the invention is not limited to this, and each of the multiple inspection areas, each including the inspection dots, may be obtained from the overall image by changing the shooting range of the shooting device 10. In this case, a well-known mechanism for moving the shooting device 10 can be applied. Moreover, multiple shooting devices capable of separately shooting each of the multiple inspection areas may be installed. In this case, a mechanism for moving the shooting device 10 is unnecessary.

[0055] Furthermore, in the example described above, the reference position of the inspection point P was the adjacent point Q, the end T of the workpiece W, and the R section R, but other positions can also be used as reference positions. Other reference positions may include, for example, the positions where bolts, nuts, washers, etc., are joined to the workpiece W, or the joints when welded members are overlapping.

[0056] Furthermore, although the above example described the use of a circular calibration marker M, the method is not limited to this, and calibration markers M of various shapes can be applied. Alternatively, the imaging device 10 can be fixed in a fixed position directly in front of the workpiece W, thereby maintaining a constant distance per pixel in the image. In this case, the operator does not need to attach the calibration marker M to the workpiece W.

[0057] Furthermore, while the typical embodiment described an example of 100% inspection during the actual product manufacturing process using welding, the method is not limited to this and may also be used for sampling inspections or inspections of prototype parts during the manufacturing process. Specifically, prototype parts are developed based on the results of crash tests, NV performance evaluations, durability evaluations, etc. In this case, since the important inspection areas differ depending on the evaluation item, it is possible to inspect only the minimum necessary welding point positions by limiting the inspection to the important inspection areas. In addition, the amount of positional deviation can also be evaluated by calculating the distance between the inspection point P and the surrounding adjacent welding points Q, and the ends T and R of the workpiece W.

[0058] Furthermore, although the above example described a configuration in which the inspection point P to be inspected is predetermined, the operator may also appropriately select the inspection point P based on the inspection items. Specifically, the memory unit 21 stores, based on the design drawing, the positional relationship of each adjacent welding point, as well as the distance from the end T for welding points located at the end T. In this case, when the operator selects the inspection point P, the system automatically identifies the inspection area, detects the surrounding adjacent welding points Q, the end T and R portion R of the workpiece W, and makes a determination.

[0059] Furthermore, while the above example described a configuration for inspecting the location of inspection point P, a configuration can be added to inspect the number of surrounding points of inspection point P. If there are no adjacent points that match the inspection information within the inspection area of ​​inspection point P, it can be determined that the number of points is insufficient.

[0060] In the example above, workpiece W was a B-pillar of a vehicle, but this method is not limited to that; it can be applied to any part that requires spot welding in a predetermined positional relationship, such as the A-pillar, C-pillar, or front cross member. [Explanation of Symbols]

[0061] 1. Welding Inspection System 10 Imaging device 20 Inspection equipment 21 Memory section 22 Image acquisition unit 23 Detection unit 24 Calculation Section 25 Judgment section 30 Output device

Claims

1. A welding inspection device for inspecting the position of spot welds, An image acquisition unit that acquires images of a workpiece containing multiple welding points, A detection unit detects a reference position which is at least one of adjacent dots, the edge of the workpiece, and the R portion of the workpiece from within the region including the inspection dots in the captured image, A calculation unit that calculates the distance between the detected reference position and the inspection point, A welding inspection apparatus comprising a determination unit that determines whether the distance is within a predetermined range.

2. The welding inspection apparatus according to claim 1, wherein the determination unit determines whether the distance between each of the multiple reference positions and the inspection point is within a predetermined range.

3. The welding inspection apparatus according to claim 2, wherein when the reference position is at least one of the end portion and the R portion, the predetermined range is smaller compared to when the reference position is an adjacent welding point.

4. The workpiece has a circular calibration marker, The image acquisition unit acquires an image of the workpiece including the plurality of welding points and the calibration marker. The welding inspection apparatus according to claim 1, wherein the calculation unit calculates the distance based on the diameter of the calibration marker which is parallel to the line segment connecting the reference position and the inspection point in the captured image.

5. A welding inspection method for inspecting the position of spot welds, Image acquisition step: Obtaining an image of a workpiece that includes multiple welding points, A detection step in which a reference position is detected from within the region of the captured image including the inspection dots, which is at least one of adjacent dots, the edge of the workpiece, and the R portion of the workpiece, A calculation step of calculating the distance between the detected reference position and the inspection point, A welding inspection method comprising a determination step of determining whether the distance is within a predetermined range.

6. The welding inspection method according to claim 5, wherein the determination step determines whether the distance between a plurality of reference positions and the inspection point is within a predetermined range.

7. The welding inspection method according to claim 6, wherein, within the area of ​​the captured image, if the reference position is at least one of the end portion and the R portion, the predetermined range is smaller compared to the case where the reference position is an adjacent welding point.

8. The workpiece has a circular calibration marker, The image acquisition step involves acquiring a captured image of the workpiece including the plurality of welding points and the calibration marker, The welding inspection method according to claim 5, wherein the calculation step calculates the distance based on the diameter of the calibration marker which is parallel to the line segment connecting the reference position and the inspection point in the captured image.

9. A welding inspection system for inspecting the position of spot welds, A camera for photographing a workpiece with multiple welding points, The welding inspection device includes a device that inspects the position of the inspection point based on the image captured by the aforementioned photographic device, The welding inspection device is A detection unit detects a reference position which is at least one of an adjacent point, the edge of the workpiece, and the R portion of the workpiece from within the region of the captured image that includes the inspection point, A calculation unit that calculates the distance between the detected reference position and the inspection point, A welding inspection system comprising a determination unit that determines whether the distance is within a predetermined range.

10. The welding inspection device is equipped with an output device that outputs the inspection results from the determination unit of the welding inspection device, The welding inspection system according to claim 9, wherein the output device displays, along with the inspection result, at least one of the distance to the reference position and the determination result of normality or abnormality based on the distance on the captured image.

Images