Image processing control of a manual welding operation

Abstract

The present invention relates to a computer-implemented method for controlling a manual welding operation, comprising the following steps: - determination (S1) of reference welding parameters associated with the welding operation; - during the welding operation, acquisition (S2) of a plurality of images including the area to be welded (1) and the welding torch (2); - processing of the acquired images (S3) to determine welding parameters; and - comparison (S4) of the welding parameters with the reference welding parameters to verify the conformity of the welding operation with respect to the reference welding parameters. Figure for the abstract: Fig. 2

Description

Title of the invention: Image processing control of a manual welding operation. Technical field

[0001] Welding operations and the resulting welds are subject to strict quality requirements to guarantee the quality and service life of the parts produced. Welding operations are generally qualified by type, material type, process, machine, and operator (welder). STATE OF THE ART

[0002] In the case of an automated welding operation, the welding parameters are controlled in real time by the welding machine operator. The conditions of the welding operation are therefore not only controlled simply and efficiently in real time, but can also be automatically recorded, thus enabling a correlation over time between the workpiece and the welding operation.

[0003] Such information is, however, more difficult to obtain in the case of a manual welding operation. Indeed, since the welding generator is set by an operator (the welder), the result of the weld necessarily depends on the operator's skill. Moreover, since weld quality can only be checked at the end of the welding operation, it necessarily implies an additional loss of time and, if necessary, subsequent repair steps that can prove costly. Finally, since the welding is performed manually, it is difficult to identify the causes of any weld defects. EXPOSED

[0004] One purpose of the present application is to remedy the aforementioned disadvantages of manual welding operations.

[0005] To this end, according to a first aspect, a computer-implemented control method for controlling a manual welding operation of a welded area of ​​at least one part is proposed, comprising the following steps: - determination of reference welding parameters associated with the welding operation of the area to be welded; - during the welding operation of the area to be welded using a manual welding torch, acquisition of a plurality of images including the area to be welded and the welding torch; - processing of acquired images to determine welding parameters for the welding operation; and - comparison of welding parameters with reference welding parameters in order to verify conformity of the welding operation according to the reference welding parameters.

[0006] Of course, the invention can also be implemented in the context of an automatic or semi-automatic welding operation.

[0007] Some preferred but not limiting features of the control process according to the first aspect are the following, taken individually or in combination: - the welding parameters include at least one of the following parameters: a preheating temperature of the area to be welded, a welding temperature of the area to be welded, an air gap distance of the area to be welded, a travel speed of the welding torch and a deposition angle of a filler metal; - the comparison and verification step is carried out in real time, during the welding operation; - the process also includes, prior to the welding operation, a geometric control step of the area to be welded; - the geometric control stage of the area to be welded, comprising the following sub-stages: - determination of reference geometric parameters associated with the area to be welded; - acquisition of a plurality of starting images including the area to be welded; - processing of the initial images to determine the geometric parameters of the area to be welded; and - comparison of geometric parameters with reference geometric parameters in order to verify the conformity of the area to be welded according to the reference geometric parameters; - each reference welding parameter includes a reference tolerance, the control process further including a step of generating an alert if the comparison between at least one welding parameter and the associated reference welding parameter exceeds the reference tolerance associated with that reference welding parameter; - each reference welding parameter includes a reference tolerance, the inspection process further including a welding operation correction step if the comparison between at least one welding parameter and the associated reference welding parameter exceeds the reference tolerance associated with that reference welding parameter; and / or - the process further includes a data recording step linking the determined welding parameters and the area to be welded in a database.

[0008] According to a second aspect, a control device is proposed that is configured to control a manual welding operation according to the first aspect, the control device comprising: - a storage device configured to store information relating to at least one area to be welded and reference parameters associated with a welding operation corresponding to the area to be welded; - a controller configured for: * determine the reference welding parameters associated with the welding operation; * process the images to determine the welding parameters of the welding operation; and * Compare the welding parameters with the reference welding parameters to verify that the welding operation conforms to the reference welding parameters; and - an image acquisition device configured to acquire the plurality of images including the area to be welded and the welding torch during the welding operation.

[0009] Some preferred but non-limiting features of the control device according to the second aspect are as follows, taken individually or in combination: - the device further includes additional storage means configured to record data linking welding parameters and the area to be welded in a database; - the device further includes at least one marker configured to be fixed on or near at least one of the following: the workpiece, the welding torch, and / or - the image acquisition device is fixed on a support configured to be worn by an operator performing the welding operation.

[0010] According to a third aspect, a computer program is proposed comprising program code instructions for the execution of the steps of the process according to the first aspect when said program is executed on a computer. DESCRIPTION OF THE FIGURES

[0011] Other features, purposes and advantages will become apparent from the following description, which is purely illustrative and not limiting, and which should be read in conjunction with the accompanying drawings on which:

[0012] Fig. 1 schematically illustrates an example of a control device conforming to an embodiment;

[0013] Fig. 2 is a flowchart of steps of an example of a control process according to an embodiment.

[0014] Throughout the figures, similar elements bear identical references. DETAILED DESCRIPTION

[0015] The following will describe a method for controlling a manual welding operation of a weld area 1 of a part using a manual welding generator 2. The weld area 1 may comprise a portion of a given part, or correspond to the interface between this part and another additional part for the purpose of joining them.

[0016] The control method can be implemented to control the welding operation, regardless of the type of manual welding generator 2. By way of non-limiting examples, the welding generator 2 can include a welding generator 2 with filler metal (for example of the MIG / MAG (English acronym for Metal Inert Gas and Metal Active Gas), TIG (English acronym for Tungsten Inert Gas), arc welding with consumable electrode, etc.) or without filler metal (autogenous welding).

[0017] The control method is implemented by a control device 3 comprising a controller 4, a storage means 5, and an image acquisition device 6 in order to monitor welding parameters of the welding operation and compare them to pre-established reference parameters. The control device 3 may be fixed or mounted on one or more objects 7 that can be worn by the operator (for example, the welder), such as a protective helmet, safety glasses, a harness, or the torch of the welding generator 2, etc.

[0018] More specifically, a method for controlling a manual welding operation of the area to be welded 1 is proposed, comprising the following steps: SI: determination, by controller 4, of reference welding parameters associated with the welding operation of the area to be welded 1; S2: during the welding operation of the area to be welded 1, acquisition by the acquisition device 6 of a plurality of images including the area to be welded 1 and the welding torch 2; S3: Processing by controller 4 of the acquired images to determine the welding parameters of the welding operation; and S4: comparison by controller 4 of the welding parameters with the reference welding parameters in order to verify conformity of the welding operation according to the reference welding parameters.

[0019] Welding parameters are parameters used to characterize the welding operation and correspond either to parameters related to the implementation of the welding generator 2 during the welding operation, i.e. to the area to be welded 1. The welding parameters may include at least one of the following parameters: a preheating temperature of the area to be welded 1, a welding temperature of the area to be welded 1, an air gap distance of the area to be welded 1, a travel speed of the welding torch 2 (welding speed) and a filler metal deposition angle.

[0020] In one embodiment, all of these welding parameters are measured during the welding operation. Indeed, determining these welding parameters makes it possible to control the quality of the weld obtained, without requiring direct inspection of the weld itself.

[0021] The controller 4 may, for example, include a memory in which the code instructions for executing the control method of the control device 3 are stored, and a computer of the type controller 4, microcontroller 4, microcontroller 4, etc., configured to execute these code instructions. The controller 4 may, for example, include a computer.

[0022] The image acquisition device 6 may include any device capable of acquiring images enabling the determination, by image processing, where appropriate in combination with an additional device 8, of the welding parameters.

[0023] For example, in the case of welding parameters including a welding torch travel speed 2, the control device 3 may include at least one of the following sets: • a three-dimensional camera configured to produce a three-dimensional image of the area to be welded 1 and of the welding device; • at least two two-dimensional or three-dimensional cameras configured to produce, after image processing, a three-dimensional image of the area to be welded 1 and the welding torch 2; • at least one two-dimensional (resp. three-dimensional) camera configured to produce a two-dimensional (resp. three-dimensional) image of the area to be welded 1 and the welding torch 2, and a distance measuring device (such as a lidar) whose relative position with respect to the camera and / or absolute position are known, configured to determine a distance between the distance measuring device and the area to be welded 1 and / or the welding torch 2; • at least one two-dimensional or three-dimensional camera with integrated artificial intelligence configured to produce, after image processing, a three-dimensional image of the area to be welded 1 and the welding torch 2; and / or • a non-contact three-dimensional measuring machine, for example by laser pointing.

[0024] When the welding parameters include a temperature measurement, the control device 3 may further include a thermal camera or any other thermal probe capable of measuring a temperature, preferably without contact.

[0025] The reference welding parameters determined in step SI are reference values ​​for the welding parameters determined in step S3. Therefore, when the control process determines a preheating temperature for the area to be welded 1 in step S3, the reference welding parameters determined in step SI include one or more target values ​​for the preheating temperature.

[0026] The reference welding parameters are pre-calculated for each welding zone and each associated welding operation and are pre-recorded in a storage device. These may be, for example, the parameters of a welding procedure, which includes information relating to the preheating of the welding zone, the welding speed, the deposition angle, etc., or parameters of a model generated on a computer-aided design (CAD) software for 3D design and modeling (such as Inventor software) or measured on a reference part.

[0027] It should also be noted that all or part of the welding parameters and reference welding parameters may vary over time between the start and end of the welding operation. For example, the welding speed may vary between the start and end of the welding operation, depending on the requirements of the workpiece.

[0028] An example of a control method will now be described.

[0029] During step SI, the reference welding parameters are determined. For this purpose, an operator (for example, the welder) can provide the controller 4, via an interface, with data relating to the area to be welded 1 and the welding operation. To this end, the controller 4 may include a database, stored in the storage device, comprising several welding areas and, for each welding area, at least one associated welding operation, and the operator can select from this database the welding area and the welding operation to be controlled.

[0030] The controller 4 then obtains the reference welding parameters from these data.

[0031] Alternatively, the part comprising the area to be welded 1 may include a QR code. The operator can then scan the QR code with the control device 3, thus enabling the controller 4 to obtain the reference welding parameters.

[0032] According to yet another variant, the operator can manually enter all or part of the reference welding parameter values ​​into the control device 3.

[0033] The welding operation of the area to be welded 1 can then begin.

[0034] During step S2, the controller 4 sends instructions to the image acquisition device 6 to acquire a plurality of images including the area to be welded 1 and the welding torch 2.

[0035] Step S2 is simultaneous with the welding operation.

[0036] In one embodiment, step S2 is carried out continuously, throughout the entire duration of the welding operation.

[0037] Alternatively, step S2 can be carried out in a discrete manner, with the image acquisition device 6 capturing images of the area to be welded 1 and the welding torch 2 at a predetermined frequency, for example ten images per minute.

[0038] It should be noted that, during the S2 acquisition step, the images can be taken from several different viewpoints, by moving the acquisition device 6 and / or the area to be welded 1.

[0039] Depending on the welding parameters controlled by the control device 3, the controller 4 can send instructions to additional devices 8 to perform further measurements during the welding operation, typically distance measurements (using a lidar, for example) or temperature measurements (using a thermal imaging camera, for example). Again, the additional measurements can be performed continuously or at a predetermined frequency, which depends on the welding parameters being measured. A temperature measurement, for example, can be performed at a lower frequency than a welding speed measurement.

[0040] In one embodiment, the control device 3 further includes one or more markers 9 configured to be fixed on or near the welding area and / or the welding torch 2. The markers 9 thus make it possible, during image processing in step S2, and in particular in the absence of a distance measuring device, to determine the position of the welding torch 2 and the welding area relative to the image acquisition device 6 and to deduce positioning, dimension and / or displacement information.

[0041] During step S3, the controller 4 determines, from the images and, where applicable, additional measurements, the welding parameters of the welding operation. In particular, the controller 4 can generate, from image processing and additional measurements, a vector database comprising, for each measurement instant, a value for each welding parameter (each vector in the database comprising N dimensions, where N is equal to the number of welding parameters being monitored).

[0042] For example, the advance rate can be determined by the controller 4 from the duration of the image acquisition step S2 and the length to be welded. According to another example, the preheating temperature of the weld zone 1 and the welding temperature of the weld zone 1 can be determined by the controller 4 by Image processing using a thermal camera. As another example, welding defects can be determined by controller 4 from a database containing images associated with predetermined defect types.

[0043] Step S3 is applied to all or part of the images produced in step S2. Preferably, step S3 is applied to images acquired during the entire duration of the welding operation, in order to control the entire welding operation, typically to all the images acquired in step S2.

[0044] During step S4, the welding parameters are compared with the reference welding parameters in order to verify the conformity of the welding operation.

[0045] To this end, each welding parameter obtained in step S3 is compared to the corresponding reference welding parameter, for example by comparing the parameter values ​​(temperature, speed, distance, etc.). Furthermore, each reference welding parameter has a predefined tolerance associated with it, which is stored in the storage device. The predefined tolerance can be determined by calculations and / or tests.

[0046] If the controller 4 determines that the difference between the parameter values ​​exceeds the predefined tolerance, the controller 4 deduces a non-conformity. The controller 4 can then send an alert to an operator, for example, the welder. The alert may, for example, include an audible or visual alert. Optionally, the alert also includes at least one of the following pieces of information: information relating to the difference between the parameter values ​​(percentage deviation between the values, etc.), information relating to the correction to be made to the area to be welded 1 and / or the welding process (for example, modifying the travel speed, the deposition angle, etc.).

[0047] If necessary, controller 4 can generate a report summarizing the results of the comparison in step S4. The report may include at least one of the following pieces of information: - a conformity qualification (compliant / non-compliant); - an overall quantified quality rating, which depends on the difference between the values ​​of the welding parameters and the corresponding reference welding parameters; - where applicable, information relating to the difference between the values ​​of the welding parameters and the reference welding parameters, when the difference exceeds the predefined tolerance; - where applicable, information regarding the corrections to be made.

[0048] This report is then recorded in a database 10, for example in the cloud, in a part quality folder.

[0049] Preferably, step S4 is applied to all welding parameters determined in step S3 in order to control the entire welding operation.

[0050] In one embodiment, steps S3 and S4 are performed in real time during the welding operation. This embodiment reduces the overall duration of the inspection process and provides the operator with real-time information on the conformity of the welding operation. In this case, the controller 4 sends an alert to the operator as soon as a non-conformity is detected, allowing the welder to correct the welding operation instantly. For example, the controller 4 can display the alert in safety glasses worn by the operator or generate an audible alert in the operator's protective helmet.

[0051] Alternatively, steps S3 and S4 can be carried out in whole or in part after the welding operation has been completed. The alert is then sent to the operator at the end of the welding operation.

[0052] Advantageously, information related to weld conformity can be obtained quickly, just after the welding operation.

[0053] Optionally, the process may further include an optional initial step S0, during which the weld area 1 is inspected. Indeed, welding operations generally require prior preparation of the weld area 1 to ensure weld quality. Preparation of the weld area 1 may, for example, include creating chamfers, machining the weld area 1 to create a weld gap between two parts, reducing the part thickness, etc.

[0054] The S0 step of checking the weld area 1 can then be carried out using the checking device 3 and comprise the following sub-steps: - determination by controller 4 of reference geometric parameters associated with the area to be welded 1; - acquisition of a plurality of starting images including the area to be welded 1 using the image acquisition device 6; - processing of the initial images by controller 4 to determine the geometric parameters of the area to be welded 1; and - comparison of the geometric parameters with the reference geometric parameters by the controller 4 in order to verify the conformity of the area to be welded 1 according to the reference geometric parameters.

[0055] Alternatively, step S0 can be carried out by any other suitable device, depending on the geometric parameters measured, for example, using a two-dimensional or three-dimensional laser profilometer.

[0056] It will be understood, of course, that the reference geometric parameters correspond to the geometric parameters that the area to be welded should comply with. 1 after the preliminary preparation step of the area to be welded 1. These reference geometric parameters may include at least one of the following parameters: the gap (distance) between the part to be welded and an additional part; an inclination of the torch relative to the area to be welded 1; geometric measurements of a chamfer of the area to be welded 1; etc. These may be, for example, the geometric parameters of a model generated on a 3D design and modeling software (such as Inventor) or measured on a reference part.

Claims

Demands

1. A computer-implemented method for controlling a manual welding operation of a weld area (1) of at least one part, comprising the following steps: - determining (S1) reference welding parameters associated with the welding operation of the weld area (1); - during the welding operation of the weld area (1) using a manual welding torch (2), acquiring (S2) a plurality of images including the weld area (1) and the welding torch (2); - processing the acquired images (S3) to determine welding parameters of the welding operation; and - comparing (S4) the welding parameters with the reference welding parameters to verify conformity of the welding operation with respect to the reference welding parameters.

2. A method according to claim 1, wherein the welding parameters include at least one of the following parameters: a preheating temperature of the area to be welded (1), a welding temperature of the area to be welded (1), an air gap distance of the area to be welded (1), a travel speed of the welding torch (2) and a filler metal deposition angle.

3. A method according to any one of claims 1 and 2, wherein the comparison and verification step is carried out in real time, during the welding operation.

4. A method according to any one of claims 1 to 3, further comprising, prior to the welding operation, a step (SO) of geometric control of the area to be welded (1).

5. A method according to claim 4, wherein the geometric control step (SO) of the weld zone (1) comprises the following substeps: - determination of reference geometric parameters associated with the weld zone (1); - acquisition of a plurality of starting images including the weld zone (1); - processing of the starting images to determine geometric parameters of the weld zone (1); and - comparison of geometric parameters with reference geometric parameters in order to verify conformity of the area to be welded (1) according to the reference geometric parameters.

6. A method according to any one of claims 1 to 5, wherein each reference welding parameter includes a reference tolerance, the control method further comprising a step (S5) of generating an alert if the comparison between at least one welding parameter and the associated reference welding parameter exceeds the reference tolerance associated with that reference welding parameter.

7. A method according to any one of claims 1 to 6, wherein each reference welding parameter includes a reference tolerance, the inspection method further comprising a step (S6) of correcting the welding operation if the comparison between at least one welding parameter and the associated reference welding parameter exceeds the reference tolerance associated with that reference welding parameter.

8. A method according to any one of claims 1 to 7, further comprising a data recording step (S7) (10) linking the determined welding parameters and the area to be welded (1) in a database.

9. A control device (3) configured to control a manual welding operation according to any one of claims 1 to 8, the control device (3) comprising: - a storage device (5) configured to store information relating to at least one weld area (1) and to reference parameters associated with a welding operation corresponding to the weld area (1); - a controller (4) configured to: * determine the reference welding parameters associated with the welding operation; * process the images to determine the welding parameters of the welding operation; and * compare the welding parameters with the reference welding parameters to verify the conformity of the welding operation with respect to the reference welding parameters; and - an image acquisition device (6) configured to acquire the plurality of images including the area to be welded (1) and the welding torch (2) during the welding operation.

10. Control device (3) according to claim 9, further comprising additional storage means (9) configured to record data linking welding parameters and the area to be welded (1) in a database.

11. Control device (3) according to any one of claims 9 and 10, further comprising at least one marker (9) configured to be fixed on or near at least one of the following: the workpiece, the welding torch (2).

12. Control device (3) according to any one of claims 9 to 11, wherein the image acquisition device (6) is fixed on a support (7) configured to be worn by an operator performing the welding operation.

13. Computer program comprising program code instructions for carrying out the steps of the process according to any one of claims 1 to 8 when said program is executed on a computer.

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