Welding measurement system

Abstract

The present invention aims to provide a welding measurement system and a welding measurement method capable of regularly capturing welding phenomena in manual arc welding in which the moving speed of a welding torch is irregularly changed. To this end, in a welding measurement system for measuring welding phenomena in manual arc welding, there are provided a camera track provided along a welding line, a camera capable of moving on the camera track, a camera drive device for driving the camera, and a computer for detecting the position of an arc within an image captured by the camera and controlling the camera drive device so that the camera moves at a speed at which the position of the arc is continuously displayed within a prescribed region of the image captured by the camera.

Description

Technical Field

[0001] This invention relates to a system and method for measuring welding phenomena. Background Technology

[0002] The manufacturing environment is undergoing dramatic changes in today's society. For example, increased overseas production and sourcing of components from abroad, coupled with a decrease in skilled workers, have made it difficult to maintain manufacturing skills, and quality management faces even more severe challenges. The traditional method of skills transfer is through direct instruction from skilled workers. However, this method is insufficient, often relying on intuitive guidance. Such guidance is time-consuming or prone to inaccuracies, thus hindering complete skill transmission and raising concerns about its potential loss.

[0003] On the other hand, due to the development of measurement technology in recent years, attempts have been made to measure and evaluate skilled techniques. As a method to address the problems in traditional skills transfer, the following attempt has been made: using various measuring devices to measure and evaluate the work of the trainee. A method has been proposed that compares the measured data with past measurement data to evaluate whether it is qualified, and uses this information for quality management and welding operation training. Prior art documents disclosing this method include, for example, Patent Document 1.

[0004] Patent Document 1 discloses a welding quality evaluation device equipped with: a display that shows images captured by four cameras along with welding current and voltage signals obtained from a welding current and voltage measuring device. The cameras include: a molten pool observation camera, movably fixed to the welding device and moving with the welding progress to observe torch movement and molten pool surface movement; a backwave observation camera, moving integrally with the molten pool observation camera to measure the melting state on the back side of the molten pool; a torch camera, mounted on the welding torch to monitor the melting state and arc state; and an overall movement camera that captures the welder's posture and the general condition of the weld; a storage device that stores and analyzes the image information captured by the four cameras along with the welding current and voltage signals obtained from the welding current and voltage measuring device; and a welding protective surface equipped with a small monitor displaying any one of the images captured by the four cameras.

[0005] Furthermore, Patent Document 1 describes the method for moving the molten pool observation camera and the backwave observation camera as follows: "The molten pool observation camera and the backwave observation camera in the welding quality evaluation device of the present invention are disposed above and below the base material, and move integrally along the bevel as welding progresses. The moving speed of these molten pool observation cameras and the backwave observation cameras can be set to a predetermined model speed, or it can be set to a speed synchronized with the moving speed of the welding torch based on image information from the overall movement camera that captures the welder's posture."

[0006] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2013-91086 Summary of the Invention

[0007] However, when the moving speed of the molten pool observation camera is set to the "specified model speed", when the moving speed deviates from the "specified model speed", the shooting distance and shooting angle of the molten pool will change, making it impossible to regularly capture the welding phenomenon.

[0008] Furthermore, although it is recorded that the moving speed of the molten pool observation camera can be set to "the speed synchronized with the moving speed of the welding torch based on image information from the overall movement camera that captures the welder's posture," it takes time to calculate the moving speed of the welding torch based on image information from the overall movement camera, and there are concerns that the tracking accuracy of the molten pool observation camera relative to the moving welding torch cannot be guaranteed.

[0009] Furthermore, with the methods described above, image processing parameters need to be adjusted again when the camera configuration and welding position change, thus altering the shooting conditions. Moreover, there are concerns that the tracking accuracy of the camera observing the molten pool may not be guaranteed when the arc state changes during welding, thus altering the optimal shooting conditions.

[0010] The present invention was made in view of the above-mentioned problems, and its object is to provide a welding measurement system and welding measurement method that can regularly capture welding phenomena in manual arc welding where the moving speed of the welding torch varies irregularly.

[0011] To achieve the above objectives, the welding measurement system of the present invention measures the actions of a welder in manual arc welding. The welding measurement system includes: a first camera track disposed along the welding line; a first camera movable on the first camera track; a first camera drive device for driving the first camera; and a computer that detects the position of the arc within an image captured by the first camera and controls the first camera drive device such that the first camera moves at a speed such that the position of the arc is continuously displayed within a predetermined area of ​​the image captured by the first camera.

[0012] Furthermore, the welding measurement method of the present invention moves a camera to measure welding phenomena in manual arc welding. The welding measurement method includes the following steps: adjusting the position of the camera before welding begins so that the welding start point is within the field of view of the camera; starting to capture images with the camera before welding begins; moving the camera after welding begins so that the position of the arc in the image captured by the camera is continuously displayed within a predetermined area of ​​the image; and stopping the movement of the camera and continuing to capture images when the arc disappears.

[0013] According to the present invention configured as described above, in manual arc welding where the moving speed of the welding torch varies, the arc can be captured within a specified area of ​​the image captured by the camera, thereby enabling the welding phenomenon to be captured regularly.

[0014] Invention Effects According to the present invention, in manual arc welding where the torch moving speed varies irregularly, welding phenomena can be captured in a regular manner. Attached Figure Description

[0015] Figure 1 This is a diagram showing the overall configuration of the welding measurement system according to the first embodiment of the present invention.

[0016] Figure 2 This is a flowchart illustrating the processing of the control unit in the first embodiment of the present invention.

[0017] Figure 3 This is a diagram showing the overall configuration of the welding measurement system according to the second embodiment of the present invention.

[0018] Figure 4 This is a flowchart illustrating the processing of the control unit in the third embodiment of the present invention.

[0019] Figure 5 This is a diagram showing the overall configuration of the welding measurement system according to the fourth embodiment of the present invention.

[0020] Figure 6This is a diagram showing the welding measurement system of the fourth embodiment of the present invention viewed from above.

[0021] Figure 7 This is a flowchart illustrating the processing of the control unit in the fourth embodiment of the present invention.

[0022] Figure 8 This is a diagram illustrating an image captured by the first camera in the fourth embodiment of the present invention, and an example of the binarized image.

[0023] Figure 9 This is a diagram showing the overall configuration of the welding measurement system according to the fifth embodiment of the present invention.

[0024] Figure 10 This is a diagram showing the welding measurement system in the fifth embodiment of the present invention viewed from above.

[0025] Figure 11 This is an overall configuration diagram of the welding measurement system according to the sixth embodiment of the present invention.

[0026] Figure 12 This is a diagram showing the welding measurement system of the sixth embodiment of the present invention viewed from above.

[0027] Figure 13 This is a diagram illustrating an image captured by the second camera in the sixth embodiment of the present invention, and an example of the binarized image. Detailed Implementation

[0028] Hereinafter, embodiments of the present invention will be described using the accompanying drawings. Furthermore, in each drawing, the same reference numerals are used to label equivalent elements, and redundant descriptions are omitted where appropriate.

[0029] Example 1 Figure 1 This diagram shows the overall configuration of the welding operation measurement system according to the first embodiment of the present invention. The welding operation is envisioned as upward vertical welding. The test piece is not shown in the diagram, but it is shown with a V-groove. In addition, the welding is set as MAG welding with many sparks.

[0030] Figure 1 In this diagram, 101 represents the control unit, 102 represents the welding phenomenon measurement unit, 103 represents the measurement unit drive unit, 104 represents the welder, 105 represents the light-shielding surface, 106 represents the welding torch, 107 represents the object being welded, and 108 represents the semi-automatic welding power supply. The control unit 101, for example, is a computer, and includes: an arithmetic processing unit (e.g., a CPU); a storage device (e.g., semiconductor memory such as ROM or RAM, and magnetic storage device such as HDD, equivalent to "storage unit" hereinafter referred to as such) storing programs and data to be executed by the arithmetic processing unit; and a display device (e.g., a monitor or touch panel) displaying the calculation results of the arithmetic processing unit.

[0031] The control unit 101 consists of a welding phenomenon calculation unit 110 that acquires information from the welding phenomenon measurement unit 2 and performs appropriate calculations, a measurement unit drive control unit 120 that calculates and controls the measurement unit drive unit 103 based on the information from the welding phenomenon calculation unit 110, and a welding operation evaluation unit 130 that evaluates welding quality and welding operation based on the information from the welding phenomenon calculation unit 110. These processes are executed within a computer used for processing.

[0032] The welding phenomenon calculation unit 110 consists of an acquisition unit 111 that acquires welding phenomena and a calculation unit 112 that appropriately calculates information such as the shape and area of ​​the molten pool 161 based on the acquired welding phenomena.

[0033] The measurement unit drive control unit 120 consists of a drive calculation unit 121 and a database 122. The drive calculation unit 121 will be described in detail using the flowchart described later.

[0034] The welding operation evaluation unit 130 consists of a database 131 that stores data on welding operation and welding quality based on information from the welding phenomenon calculation unit 110, a comparison unit 132 that compares the actual welding phenomenon with the welding phenomenon stored in the database 131, and an evaluation unit 133 that evaluates the welding operation based on the comparison results of the comparison unit 132.

[0035] Alternatively, it can be configured to include a database supplement 134, which interpolates data from the existing database 131 for welding phenomena not recorded in the database 131. Alternatively, it can be configured to include a display unit 135 that displays the evaluation results by the evaluation unit 133. The display unit 135 can be configured to display the current and voltage values ​​during welding by connecting the control unit 101 to a digital welding power supply.

[0036] Regarding the comparison unit 132 and the evaluation unit 133, it is preferable that they can extract, evaluate, and display items such as brightness, length, width, area, roundness, and aspect ratio of the molten pool 161. In this embodiment, since the distance from the welding phenomenon measurement unit 102 to the welding position is fixed, the welding phenomenon can be compared with higher accuracy than before.

[0037] Alternatively, the comparison unit 132 can be configured to calculate the ideal welding phenomenon from the welding phenomena of multiple skilled welders through machine learning, without referring to the database 131 that records welding phenomena.

[0038] The display unit 135 can be configured to display information to personnel outside the welding work area using a display, or it can be configured to display information using a small display or the like on the light-shielding surface 105, and feed back welding information to the welder 104 one by one.

[0039] In actual operation, the measurement unit measures the movement of the welding torch 106 when the welder 104 welds the object 107. The welding phenomenon measurement unit 102 is positioned around the welder 104 and the object 107. The welding phenomenon measurement unit 102 is designed to move along a camera track 150. The camera track 150 is arranged parallel to the welding line 107a of the object 107.

[0040] As the welding phenomenon measurement unit 102, examples include CMOS cameras and high-speed cameras. To capture the welding phenomenon, it is preferable to appropriately use a filter that filters the entire light source and a short-pass filter, long-pass filter, or band-pass filter that filters the wavelength. For example, a wavelength around 900nm to 1000nm can be considered as the filter. Furthermore, it is preferable to use protective glass to prevent damage from fumes and sparks 162.

[0041] The welding phenomenon measuring unit 102 can be equipped with two or more measuring devices besides a camera. Other measuring devices could include, for example, a thermal imaging camera. Alternatively, multiple cameras can be used for measurement. This could include methods for three-dimensional measurement, such as using the principle of a stereo camera.

[0042] The measuring unit drive unit 103 drives the welding phenomenon measuring unit 102 in accordance with the movements of the welder 104. Preferably, it is a mechanism capable of driving parallel to the welding line 107a. Since this embodiment involves upward vertical welding, the measuring unit drive unit 103 is also configured to move from bottom to top. If the welding line 107a has an R-section, it is preferable to also provide the same R-section on the camera track 150. By arranging the camera track 150 parallel to the welding line 107a, even if the welding torch 106 moves, the welding phenomenon can be captured while maintaining a fixed shooting environment, such as the distance from the welding phenomenon measuring unit 102 to the welding position and the angle of the welding phenomenon measuring unit 102 relative to the welding position.

[0043] The measuring drive unit 103 is preferably equipped with the function of determining the welding speed by appropriately transmitting its own movement speed, etc., to the control unit 1. In this case, the control unit 1 can evaluate the welding operation and welding quality based on the obtained welding speed.

[0044] Figure 2 This is a flowchart illustrating the processing of the control unit 101. The flowchart will be explained below based on a series of evaluations from actual welding operations.

[0045] When the measuring unit drive unit 103 is controlled, although the control is based on the information from the welding phenomenon measuring unit, in addition to measuring the movement of the welding torch 106, the welding wire, and the arc 160 generated at the tip of the welding torch 106 and the welding wire, it also measures sparks 162, fumes, and the bevel end illuminated by the arc light. Therefore, it is important to drive the welding phenomenon measuring unit 102 with the welding torch 106 and the arc 160 generated at the tip of the welding torch as the target while excluding this information.

[0046] The calculations illustrated in this flowchart are for cases where these phenomena occur frequently. For TIG welding and other processes that do not generate much spark, these steps can be omitted. To maintain real-time performance, it is preferable to omit steps that are not necessary.

[0047] In step S101, as the operation begins, the acquisition of welding phenomena and the control of the drive unit also begin. This process can be performed slightly before the welding operation, or it can be configured to automatically start measurement based on the signal when the arc ignites.

[0048] In step S102, the acquired image is binarized using a brightness threshold. This process is used to identify the arc 160, welding torch 106, and welding wire, while removing other information such as bevel, fumes, and molten pool 161 as much as possible. In most cases, the brightness of the bevel and fumes is lower than that of the arc light, but in cases where it is difficult to distinguish them, the threshold can be set to a lower value for identification and differentiation in a later step. Additionally, sparks 62 are almost always present under illumination, and therefore are not distinguished here. Since the threshold varies depending on the type of filter, the camera aperture, current, etc., it is preferable to have a settable threshold.

[0049] In step S103, a thresholding process is performed on the binarized image to exclude elements based on image position, length, width, area, roundness, and aspect ratio. This process is used to exclude sparks 162 and bevels that were not distinguished in step S102.

[0050] Step S104 involves comparing the brightness, binarized vertical length, image position, horizontal length, area, roundness, and aspect ratio calculated in steps S102 and S103 with past and present values, and removing elements based on the changes. For example, in most cases, the moving speed of spark 162 is greater than the moving speed of welding torch 106, so it is conceivable to use a method of comparison with past speeds to eliminate elements.

[0051] Step S105 is a control method based on the data processed by steps S102 to S104. It can utilize the average value of the retained coordinate information and the center of gravity, etc. The measurement unit drive unit 103 is controlled to keep the center of gravity fixed even when the center of gravity changes.

[0052] In step S106, it is determined whether to end the acquisition of the welding phenomenon. If the determination result is negative, steps S102 to S106 are repeated until the welding phenomenon measurement is completed. If the determination result is positive, proceed to the next step.

[0053] In step S107, the acquisition of welding phenomena is completed.

[0054] The applicability and thresholds for processing various items in the above process are preferably set in the system. Furthermore, regarding the control of the measurement unit drive unit 103, it is preferable that parameters such as the upper limit speed, upper limit acceleration, and sensitivity, such as gain, can be adjusted.

[0055] In this embodiment, the welding motion measurement system measures the welder's movements during manual arc welding. The welding motion measurement system includes: a camera track 150 arranged parallel to the welding line 107a; a camera 102 capable of moving on the camera track 150; a camera drive device 103 that drives the camera 102; and a computer 101 that calculates the position of the arc 160 based on the images captured by the camera 102 and controls the camera drive device 103 in such a way that the camera 102 moves to follow the position of the arc 160.

[0056] The welding measurement system of this embodiment, configured as described above, can capture welding phenomena while maintaining a fixed distance between the camera 102 and the molten pool 161, as well as a fixed angle relative to the molten pool 161. Therefore, in manual arc welding where the moving speed of the welding torch 106 varies irregularly, welding phenomena can be captured systematically.

[0057] Furthermore, in this embodiment, the computer 101 calculates physical quantities (brightness, length, width, area, roundness, aspect ratio, etc.) representing the molten pool 161 based on the image captured by the camera 102, and displays these physical quantities along with the image captured by the camera 102. Thus, the state of the molten pool 161 can be quantitatively determined while confirming the welding phenomenon.

[0058] Furthermore, in this embodiment, the computer 101 determines whether the welding quality is acceptable based on whether the physical quantity representing the molten pool 161 converges within a reference value. This enables welding quality management.

[0059] Example 2 The welding action measurement system of the second embodiment of the present invention will be described with a focus on the differences from the first embodiment.

[0060] Figure 3 This diagram illustrates the overall configuration of the welding measurement system in this embodiment. The welding measurement system of this embodiment is compared to the welding measurement system of the first embodiment (…). Figure 1 The function of acquiring the action of welding torch 106 has been added to the (shown).

[0061] In this embodiment, a marker-type motion capture device was used to measure the welding torch 106, but other methods could also be considered. For example, an acceleration / angular velocity / geomagnetic measuring device, a Global Positioning System (GPS), an indoor GPS system, or the speed of the measurement unit drive unit 103 could be used. Furthermore, two or more of these methods could be combined. From the viewpoint of accuracy, a marker-type motion capture device is preferred.

[0062] A mark 170 is provided on the welding torch 106. Marking measurement cameras 180-182 are arranged around the welder 104 and the object being welded 107. The marking measurement cameras 180-182 can be set to a light wavelength of 350 nm to 11 μm to irradiate the mark 170, avoiding the light wavelength of the arc welding. To avoid the light from the arc 160, a wavelength of 550 nm or higher is preferably used. In this embodiment, irradiation is set to 850 nm light.

[0063] The marking and measuring cameras 180-182 are connected to the control unit 101, and the speed, height, oscillation period and amplitude, and angle of the welding torch 106 are calculated based on the information of the measured markings 170.

[0064] Furthermore, additional markings can be added to the welder 104, the light-shielding surface 105, etc. Additionally, in cases where the welding electrode is supplied from a location other than the welding torch 106, such as in TIG welding, markings can also be added to the welding electrode (not shown). By setting markings on the welder 104, the light-shielding surface 105, or the welding electrode, information such as the welder 104's body position and head position, or the amount and angle of electrode supply, can be obtained.

[0065] Information obtained from the marking and measuring cameras 180-182 is sent to the welding torch motion calculation unit 140. The welding torch motion calculation unit 140 calculates the welding torch motion and sends it to the comparison unit 132 of the welding operation evaluation unit 130.

[0066] Based on the information about the molten pool 161 described above, the comparison unit 132 and the evaluation unit 133 also refer to and evaluate the information from the welding torch motion calculation unit 140. By performing these processes, a correlation can be established between the welding torch motion and the welding phenomenon, significantly improving the evaluation effect of manual welding. Previously, it was impossible to achieve the above effect because it required stable imaging of the molten pool 161 and detailed measurement of the welding torch motion.

[0067] The welding measurement system of this embodiment has welding torch motion measuring devices 180-182 for measuring welding torch motion, and computer 101 calculates physical quantities representing the welding torch motion based on the measurement results of welding torch motion measuring devices 180-182.

[0068] In addition, the welding torch motion measuring devices 180-182 are cameras that capture images of the welding torch 106, and the computer 101 calculates the physical quantities representing the welding torch motion using a marker-type motion capture device.

[0069] In addition, the computer 101 in this embodiment displays the physical quantities representing the action of the welding torch together with the images captured by the camera 102 and the physical quantities representing the molten pool 161.

[0070] According to the welding measurement system of this embodiment, in manual welding where the speed of the welding torch 106 varies, the welding phenomenon can be captured regularly, and by measuring the action of the welding torch, information such as the cause of the change in the welding phenomenon and how the action can be changed can be provided.

[0071] Example 3 The welding action measurement system of the third embodiment of the present invention will be described with a focus on the differences from the first embodiment.

[0072] Figure 4 This is a flowchart illustrating the processing of the control unit 101 in this embodiment. The flowchart will be explained below based on a series of evaluations from actual welding operations.

[0073] Steps S111 to S117 are the same as steps S101 to S107 in the first embodiment ( Figure 2 (As shown) Same.

[0074] In step S118, image conversion and various calculations of the welding phenomenon are performed. Preferably, the calculations performed here are capable of extracting, evaluating, and displaying parameters such as brightness, length, width, area, roundness, and aspect ratio of the molten pool 161, as described above. In this embodiment, since the distance from the welding phenomenon measuring unit 2 to the welding position is fixed, comparisons that were previously impossible can be performed.

[0075] In addition, as a method for converting images, the following method can be used: the welding phenomenon measurement unit 102 is composed of multiple cameras, and multiple images taken from different angles are converted into an image that is close to the field of view of the welder 104.

[0076] The inertial sensor 114 installed on the welding torch 106 can measure the three-axis acceleration and three-axis angular velocity of the welding torch 106 (welding torch motion data). In addition to measuring acceleration, angular velocity and geomagnetism using the inertial sensor 114 and other such devices, the welding torch motion data can also be measured using a global positioning system, an indoor global positioning system, a stereo camera, etc.

[0077] In step S119, the welder's movements are evaluated. Previously acquired welding phenomenon data and optimal welding phenomenon data are pre-stored in database 131 and compared with newly measured welding phenomenon data from welding phenomenon measurement unit 102 to evaluate the welder's movements. Alternatively, regarding welding torch movements, optimal welding torch movement data can be pre-stored in database 131 and compared with newly measured welding torch movement data to evaluate the welder's movements. This allows for suggestions on how to improve the movements.

[0078] In this embodiment, the computer 101 converts the viewpoint of the image captured by the camera 102 into the viewpoint of the welder 104 for display.

[0079] By applying the welding motion measurement system of this embodiment to training systems and quality management, a welding motion measurement system can be provided that can efficiently implement skills transfer, improve manufacturing quality, and help reduce defect rates.

[0080] Example 4 Figure 5 as well as Figure 6 This diagram illustrates the overall configuration of the welding operation measurement system according to the fourth embodiment of the present invention. The welding operation is envisioned as downward welding. The test piece is not shown in the diagram, but is shown with a V-shaped bevel.

[0081] Figure 5 In the diagram, 1 represents the control unit, 2a represents the camera, 3a represents the camera driver unit, 4 represents the welder, 5 represents the workbench, 6 represents the light-shielding surface, 7 represents the welding torch, 8 represents the object being welded, and 9 represents the welding power source. The control unit 1 is, for example, a computer that includes: an arithmetic processing unit (e.g., a CPU); a storage device (e.g., semiconductor memory such as ROM or RAM, and magnetic storage device such as HDD, equivalent to "storage unit" hereinafter referred to as such) storing programs and data to be executed by the arithmetic processing unit; and a display device (e.g., a monitor or touch panel) displaying the results of the arithmetic processing unit's calculations.

[0082] The control unit 1 consists of an image processing unit 10 that processes images captured by the camera 2a, a drive control unit 20 that controls the camera drive device 3a, a storage unit 30 that stores the data processed by the image processing unit 10, and a database 40 that stores the control parameters described later.

[0083] The image processing unit 10 includes an acquisition unit 11 that acquires information such as images captured by the camera 2a, and a binarization unit 12 that binarizes the images acquired by the acquisition unit 11. For example, image binarization is performed by setting a pixel to white if the luminance of each pixel constituting the image is above a predetermined threshold, and setting it to black if the luminance is below the threshold. This processing is used to remove information other than the position and shape of the electric arc from the image captured by the camera 2a. The luminance threshold is one of the control parameters and is set according to the type of filter, the aperture of the camera, the arc current, etc.

[0084] The drive control unit 20 calculates the centroid position of the white portion (light source) of the binarized image and calculates the difference between this centroid position and a predetermined position (e.g., the center position) within the shooting frame. It determines the target speed of the camera 2a by minimizing this difference and outputs a control signal corresponding to the target speed to the camera drive device 3a. In other words, the drive control unit 20 calculates the centroid of the light source based on the image acquired by the acquisition unit 11 and performs drive control (e.g., motion control) of the camera 2a in a manner that keeps the centroid of the light source continuously displayed within a predetermined area of ​​the image (the position of the centroid is within the predetermined area).

[0085] Database 40 stores parameters related to the control of the welding measurement system (control parameters). These control parameters include the specified position within the shooting frame, maximum tracking speed, tracking gain (proportional coefficient), and brightness threshold.

[0086] The interface 50 consists of a display unit 51 and an input unit 52. The display unit 51 displays the image captured by the camera 2a, the position of the camera 2a, and its movement speed. Additionally, as needed, it can also display welding parameters output from the welding power source 9 (current value, voltage value, wire feed speed, etc.) and control parameters stored in the database 40. The display unit 51 can be configured to display information to personnel outside the welding work area using a monitor, or it can be configured to display information on a small display or similar device on the light-shielding surface 6, feeding back welding information to the welder 4 one by one. The input unit 52 is used by the system administrator and the welder 4 to start and stop the system and input control parameters stored in the database 40.

[0087] In actual welding operations, this system uses camera 2a to capture the electric arc generated when the operator, i.e., welder 4, welds the object 8 fixed to the workbench 5. Camera 2a is positioned around welder 4 and the object 8. Camera 2a is designed to move along camera track 60. Camera track 60 is positioned along the welding line 8a of the object 8.

[0088] Specific examples of camera 2a include CMOS cameras, high-speed cameras, and thermal cameras. Furthermore, to capture the welding phenomenon, it is preferable to use a filter that filters the light overall and a short-pass filter, long-pass filter, or band-pass filter that filters the wavelength. For example, wavelengths around 900nm to 1000nm can be considered as filters. Additionally, it is preferable to use protective glass to prevent damage from smoke and sparks 162. Furthermore, camera 2a is not limited to one unit; multiple units can be installed. In this case, the image can be rendered in three dimensions using principles such as stereo cameras.

[0089] The camera drive unit 3a drives the camera 2a by following the movement of the electric arc. More specifically, the drive control unit 20 monitors the image captured by the camera 2a (e.g., an image binarized by the binarization unit 12) via the image processing unit 10 and detects changes in the position of the light source's center of gravity in the image. Furthermore, the drive control unit 20 calculates the driving conditions (e.g., movement direction, movement speed, target position, etc.) of the camera 2a in a manner that restores the position of the light source's center of gravity in the image to its previous position. The drive control unit 20 outputs this information to the camera drive unit 3a, which then moves the camera 2a along the camera track 60 based on this information. The drive control unit 20 and the camera drive unit 3a perform this action in real time during the welding operation. Thus, the camera 2a moves along the camera track 60 in a manner that follows the movement of the electric arc.

[0090] For example, the camera track 60 is configured such that even as the welding operation progresses, the camera 2a can be moved to continuously capture the electric arc (continuously entering the field of view). For example, in this embodiment, since the welding line 8a is assumed to be straight, the camera track 60 is configured such that the straight track is parallel to the welding line 8a. Therefore, this embodiment employs a mechanism that can be driven parallel to the welding line 8a, but parallelism is not necessarily required.

[0091] For example, the camera track 60 does not need to be a perfectly straight line, nor does it need to be perfectly parallel to the welding line 8a. For example, the camera track 60 can be slightly curved, or configured to be slightly angled relative to the welding line 8a. Furthermore, if the welding line 8a is envisioned to have bent portions (e.g., curved and folded portions), the camera track 60 can have portions that correspond to the bends. For example, if the welding line 8a has an R-shaped portion, it is preferable that the same R-shaped portion is also provided on the camera track 60. In other words, the camera track 60 only needs to be configured along the welding line 8a.

[0092] Furthermore, when the camera track 60 is arranged parallel to the welding line 8a, even if the welding torch 7 moves, the welding phenomenon can be captured while keeping the shooting environment, such as the distance from the camera 2a to the welding position and the angle of the camera 2a relative to the welding position, fixed.

[0093] The camera driving device 3a preferably has the function of sending the driving conditions of the camera 2a, such as the moving speed, to the control unit 1. In this case, the control unit 1 calculates the welding speed based on the moving speed of the camera 2a, thereby enabling the evaluation of the welding operation and welding quality.

[0094] Figure 7 This is a flowchart illustrating the processing of the control unit 1. The process can be initiated by receiving instructions from the welder 4 or other operators, or it can be automatically executed upon detecting an increase in the current value during arc ignition. Furthermore, in this embodiment, the following scenario is described: before starting the process, the welder 4 adjusts the position and angle of the camera 2a to bring the welding start point within the field of view, and the operation of the control unit 1 begins upon activating the camera 2a.

[0095] The control unit 1 first acquires the image captured by the camera 2a (step S1).

[0096] Next, in step S1, the image obtained in step S1 is binarized using a luminance threshold (step S2). Figure 8 This image shows an example of an image captured by camera 2a and its binarized form. In the unbinded image, the nozzle, molten pool, welding wire, and arc can be identified separately. In contrast, in the binarized image, areas with brightness above a threshold (the arc) are represented in white, while areas with brightness below the threshold (outside the arc) are represented in black. The speed of camera 2a is controlled so that the arc can be captured within the tracking box shown by the dashed line in the diagram.

[0097] Next, in step S2, it is determined whether there is a light source (electric arc) within the field of view of camera 2a (step S3).

[0098] If the determination in step S3 indicates that there is a light source within the field of view, the position of the center of gravity of the light source is calculated, a predetermined area including the position of the center of gravity is defined, and this area is designated as the target area for retaining the center of gravity of the light source (hereinafter referred to as the tracking frame) (step S4). Then, the movement conditions of the camera 2a, such as the target speed, are determined in a way that minimizes the difference between the position of the center of gravity of the light source and a predetermined position (e.g., the center position) within the tracking frame (step S5). This allows the arc to be captured within the tracking frame.

[0099] If the determination in step S3 is negative (no light source within the field of view), the target speed of camera 2a is set to zero (step S6). In other words, if the control unit 1 determines that there is no light source in the acquired image from the beginning, that a light source existing in the image has disappeared, or that a light source existing in the image has moved out of the field of view, it sets camera 2a to a stationary state or stops the movement of camera 2a. On the other hand, in this embodiment, the control unit 1 continues to perform the shooting action based on camera 2a even if it determines that the light source is not within the field of view. Therefore, even if the welding operation is interrupted and the arc disappears, shooting can continue while camera 2a is stationary.

[0100] Next, in step S5 or step S6, a control signal corresponding to the target speed of camera 2a is output to camera drive device 3a (step S7).

[0101] Next, in step S7, the image obtained in step S1, along with associated information (current, voltage, sound, time, camera position, etc.) related to the welding operation, is stored in storage device 30 (step S8), and the process is returned to step S1. Furthermore, the process can end slightly after the determination that the welding operation has ended, or it can be automatically executed after a decrease in the current value is detected when the arc disappears and a predetermined time has elapsed.

[0102] In addition, control unit 1 repeatedly executes the above process (e.g. Figure 7 (The process shown) continues until the welding operation is determined to be completed. For example, in manual welding operations, welding operations are sometimes interrupted and resumed. In this case, in this embodiment, the location where the welding was interrupted (the location where the light source disappeared) is continuously photographed (that is, the image processing of steps S1 and S2 continues). When the light source is detected again, at the location where the welding was interrupted, the calculation of the center of gravity position and the setting of the tracking frame in step S4, as well as the camera movement in step 5 and beyond, are resumed.

[0103] Alternatively, for example, if the control unit 1 detects that the welder 4 has stopped the operation of the camera 2a (e.g., turned the power off), it can determine that the welding operation has ended. In this case, the control unit 1 will stop the camera driving operation after this determination.

[0104] (Summarize) In this embodiment, the welding measurement system for measuring welding phenomena in manual arc welding includes: a first camera track 60 arranged along the welding line 8a; a first camera 2a movable on the first camera track 60; a first camera drive device 3a for driving the first camera 2a; and a computer 1 that detects the position of the arc in the image captured by the first camera 2a and controls the first camera drive device 3a such that the first camera 2a moves at a speed such that the position of the arc is continuously displayed within a predetermined area of ​​the image captured by the first camera 2a.

[0105] According to the above-described embodiment, in manual arc welding where the moving speed of the welding torch 7 varies irregularly, the arc can be captured within a specified area of ​​the image captured by the first camera 2a, thereby enabling the welding phenomenon to be captured regularly.

[0106] Furthermore, in this embodiment, the computer 1 detects the centroid position of the portion of the image captured by the first camera 2a that has a brightness above a predetermined threshold, and calculates this centroid position as the position of the electric arc. Therefore, the position of the electric arc can be detected based on the brightness of the image captured by the first camera 2a.

[0107] Furthermore, in this embodiment, the computer 1 binarizes the image captured by the first camera 2a based on whether its luminance is above a threshold, and calculates the centroid position of the image portion with luminance above the threshold as the position of the electric arc. This allows for the detection of the electric arc's position in a short time, thereby improving the tracking accuracy of the first camera 2a.

[0108] Furthermore, the welding measurement system in this embodiment also includes a storage device 30 for storing images captured by the first camera 2a. Therefore, the images captured by the first camera 2a can be used for various purposes.

[0109] Furthermore, in this embodiment, the computer 1 stores incidental information about the welding phenomenon along with the image captured by the first camera 2a in the storage device. Therefore, incidental information about the welding phenomenon can be confirmed in conjunction with the image captured by the first camera 2a.

[0110] Furthermore, in this embodiment, when the arc disappears, the computer 1 controls the camera drive device 3a to stop the movement of the camera 2a, and continues to acquire images captured by the camera 2a. Additionally, the welding measurement method in this embodiment, which measures welding phenomena in manual arc welding, includes the following steps: adjusting the position of the camera 2a before welding begins so that the welding start point is within the field of view of the camera 2a; starting the camera 2a to capture images before welding begins; moving the camera 2a after welding begins so that the position of the arc in the image captured by the camera 2a is continuously displayed within a predetermined area of ​​the image; and stopping the movement of the camera 2a and continuing to capture images when the arc disappears. Therefore, in the event of an interruption in the welding operation, the welding phenomenon can be measured immediately after the welding operation resumes.

[0111] Furthermore, the control modes of the camera driving device 3a and the first camera 2a based on the control unit 1 in this embodiment, such as the binarization processing of the captured image, the detection of the arc position based on the center of gravity of the detected luminance, the setting of the tracking frame and the adjustment of movement conditions such as the movement speed based thereon, the shooting control during stop, and its control flow ( Figure 7 The same applies to other embodiments, such as embodiments 1 to 3.

[0112] Example 5 The fifth embodiment of the present invention will be described focusing on the differences from the fourth embodiment.

[0113] Figure 9 This is a diagram showing the overall configuration of the welding measurement system in this embodiment. Figure 10 This is a diagram showing the welding measurement system viewed from above.

[0114] In the fourth embodiment, the camera track 60 is configured such that the moving line 60a of the camera 2a is aligned with the welding line 8a. In contrast, in this embodiment, the moving line 60a of the camera 2a is configured such that the moving line 60a is parallel to the welding line 8a and the moving line 60a is closer to the welder 4 than the welding line 8a.

[0115] In this embodiment configured as described above, the same effect as in the first embodiment can be achieved. Furthermore, by changing the configuration of the camera track 60, it is possible to capture images of the arc state, etc., at an angle that will not interfere with the welder's hands and tools.

[0116] Example 6 The sixth embodiment of the present invention will be described focusing on the differences from the fourth embodiment.

[0117] Figure 11This is a diagram showing the overall configuration of the welding measurement system in this embodiment. Figure 12 This is a diagram showing the welding measurement system viewed from above.

[0118] The welding measurement system in this embodiment also includes a second camera 2b, a second camera track 61, and a second camera drive device 3b. The second camera track 61 is disposed on the opposite side of the first camera track 60 across the worktable 5, and is configured such that the movement line 61a of the second camera 2b and the welding line 8a are aligned in a straight line.

[0119] In this embodiment, the first camera 2a simultaneously captures the completed welding line 8a and the welding operation from behind in the direction in which the welding operation is performed. On the other hand, the second camera 2b simultaneously captures the unwelded welding line 8a and the welding operation from in front in the direction in which the welding operation is performed. The processing of the control unit 1 related to the control of the second camera drive device 3b is the same as the processing of the control unit 1 related to the control of the first camera drive device 3a. Figure 7 (As shown) Similarly, the explanation is omitted here.

[0120] In this embodiment, the two camera tracks (first camera track 60 and second camera track 61) are configured to be along and separated from the welding line 8a, respectively. Two cameras (first camera 2a and second camera 2b) are respectively mounted on the first camera track 60 and the second camera track 61, allowing them to capture images of the welding line 8a from opposite angles of view, separated by the welding line 8a. Furthermore, in this embodiment, the first camera 2a and the second camera 2b are driven and controlled to move in a coordinated manner (in this embodiment, in the same direction and at the same speed).

[0121] Figure 13 This illustrates an image captured by the second camera 2b and an example of the binarized image. The control unit 1 binarizes the image captured by the second camera 2b and calculates the centroid position of the light source. It then controls the second camera drive device 3b to move the second camera 2b in a manner that minimizes the difference between the centroid position of the light source (arc) and a predetermined position within the image. Furthermore, Figure 8 This represents an image captured by the first camera 2a and an example of the binarized image.

[0122] (Summarize) The welding measurement system in this embodiment also includes: a second camera track 61 arranged along the welding line 8a; a second camera 2b that can move on the second camera track 61; and a second camera drive device 3b that drives the second camera 2b. The computer 1 detects the position of the electric arc in the image captured by the second camera 2b and controls the second camera drive device 3b so that the second camera 2b moves at a speed such that the electric arc is continuously displayed within a specified area of ​​the image captured by the second camera 2b.

[0123] According to the above-described embodiment, in manual arc welding where the torch moving speed varies irregularly, welding phenomena can be captured regularly from multiple directions.

[0124] Furthermore, in this embodiment, the first camera track 60 and the second camera track 61 are respectively arranged across the welding line 8a so that the movement line 60a of the first camera 2a and the movement line 61a of the second camera 2b are aligned with the welding line 8a. Therefore, regardless of whether the welder 4 is right-handed or left-handed, both the pre-welding and post-welding states can be captured.

[0125] The embodiments of the present invention have been described in detail above. The present invention is not limited to the above embodiments and includes various modifications. For example, the above embodiments have been described in detail for ease of understanding of the present invention, but are not limited to having all the described configurations. Furthermore, a part of the configuration of another embodiment can be added to the configuration of one embodiment, or a part of the configuration of one embodiment can be deleted or replaced with a part of another embodiment.

[0126] Explanation of reference numerals in the attached figures 1…Control unit (computer), 2a…Camera (first camera), 2b…Second camera, 3a…Camera drive unit (first camera drive unit), 3b…Second camera drive unit, 4…Welder, 5…Workbench, 6…Light shield, 7…Welding torch, 8…Welding object, 8a…Welding line, 9…Welding power source, 10…Image processing unit, 11…Acquisition unit, 12…Binarization unit, 20…Drive control unit, 30…Storage unit (storage device), 40…Database, 50…Interface, 51…Display unit, 52…Input unit, 60…Camera track (first camera track), 60a…Moving line, 61…Second camera track, 61a…Moving line, 101…Control unit (computer), 102…Welding phenomenon measurement unit (camera), 10 3… Measurement drive unit (camera drive device), 104… Welder, 105… Shading surface, 106… Welding torch, 107… Welding object, 108… Semi-automatic welding power supply, 110… Welding phenomenon calculation unit, 111… Acquisition unit, 112… Calculation unit, 114… Inertial sensor, 120… Measurement drive control unit, 121… Drive calculation unit, 122… Database, 130… Welding operation evaluation unit, 131… Database, 132… Comparison unit, 133… Evaluation unit, 134… Database supplement, 135… Display unit, 140… Welding torch motion calculation unit, 150… Camera track, 160… Arc, 161… Molten pool, 162… Spark, 170… Mark, 180~182… Marking measurement camera (welding torch motion measurement device).

Claims

1. A welding measurement system for measuring welding phenomena in manual arc welding, characterized in that it has: The track of the first camera is installed along the welding line; A first camera capable of moving along the track of the first camera; A first camera driving device that drives the first camera; and The computer that controls the first camera driver device The computer monitors the image captured by the first camera, detects the position and positional changes of the electric arc within the image, and controls the first camera drive device to move at a speed such that the first camera moves within a specified area in the image captured by the first camera while the position of the electric arc is stationary, and the position of the electric arc is continuously displayed.

2. The welding measurement system according to claim 1, characterized in that, The computer detects the center of gravity of the portion of the image captured by the first camera that has a brightness above a specified threshold, calculates the center of gravity as the position of the electric arc, and determines the speed of the first camera to reduce the difference between the center of gravity and the specified position.

3. The welding measurement system according to claim 2, characterized in that, The computer binarizes the image captured by the first camera based on whether its brightness is above a threshold, and calculates the centroid position of the image portion with brightness above the threshold as the position of the electric arc.

4. The welding measurement system according to claim 1, characterized in that, It also has a storage device for storing images captured by the first camera.

5. The welding measurement system according to claim 4, characterized in that, The computer stores information about the welding process along with images captured by the first camera in the storage device.

6. The welding measurement system according to claim 1, characterized in that, It also has: The second camera track is installed along the welding line; A second camera capable of moving on the track of the second camera; and The second camera driving device that drives the second camera. The computer monitors the image captured by the second camera, detects the position and position change of the electric arc in the image, and controls the second camera driving device to move the second camera in a manner that the position of the electric arc is within a specified area in the image captured by the second camera, and the position of the electric arc is continuously displayed.

7. The welding measurement system according to claim 6, characterized in that, The first camera track and the second camera track are respectively configured with the welding line apart, so that the movement line of the first camera, the movement line of the second camera and the welding line are in the same straight line.

8. The welding measurement system according to claim 1, characterized in that, When the electric arc disappears, the computer controls the first camera driving device to stop the movement of the first camera and continues to acquire images captured by the first camera.

Images