Welding system for real-time analysis of weld quality

Abstract

Welding system, comprehensive: a robot control module (512) configured to actuate a robot (508) and to move a welding device along a joint of metal workpieces during welding, the welding device being attached to the robot (508); a welding control module (516) configured to apply power to the welding machine, supply shielding gas to the welding machine and supply electrode material to the welding machine during welding; an image sensor (550) configured to optically measure N distances between the image sensor (550) and N locations on an outer surface of a weld bead produced along the joint by the welding machine during welding, where N is an integer greater than two; and a welding module (1116) configured for this purpose: to determine the strength of the weld bead at a point along the joint, based on: the N intervals at the point along the connection; and at least one parameter from (a) the robot control module (512) during welding, (b) the welding control module (516) during welding and / or (c) a sensor (554) configured to receive data from to capture welding during the welding process; and to store the strength of the weld and the location in the memory (1120).

Description

Introduction

[0001] The present invention relates to welding and in particular to a welding system for carrying out real-time testing of welds.

[0002] Welding is a process that joins two or more pieces of material, such as two metal parts. Welding involves using heat to melt or plasticize the material, and then cooling the material to cause the pieces to fuse or bond together.

[0003] Different types of heat sources can be used for different welding processes. For example, arc welding uses electricity. One welding process is resistance welding. Another is laser welding, which uses one or more lasers to perform the welding process. Other welding processes include, but are not limited to, electron beam welding, friction welding, and ultrasonic welding.

[0004] Resistance welding involves generating heat by passing an electric current through the resistance created by the contact between two or more metal surfaces. When a high current (e.g., 1000–100,000 amperes) is passed through the metal, small accumulations of molten metal form at the weld area.

[0005] Spot welding (or resistance spot welding (RSW)) is a resistance welding process used to join overlapping metal parts (e.g., sheets). Two electrodes simultaneously conduct current through the sheets to weld the components together. The points where current is passed through the components and they are joined can be referred to as weld points.

[0006] For further background information, reference is made in advance to the publications DE 40 14 251 A1, DE 692 06 928 T2, JP 2012- 184 996 A and CN 1 06 093 070 A. Summary

[0007] According to the invention, a welding system is presented which is characterized by the features of claim 1.

[0008] The welding system comprises: a robot control module configured to operate a robot and move a welding machine along a joint of metal workpieces during welding, with the welding machine attached to the robot; a welding control module configured to apply power to the welding machine, supply shielding gas to the welding machine, and supply electrode material to the welding machine during welding; and a vision / ...An image sensor configured to optically measure, during welding, N distances between the image sensor and N locations on an outer surface of a weld bead produced along the joint by the welding machine, where N is an integer greater than two; and a welding module configured to: determine a weld bead strength at a location along the joint based on: the N distances at the location along the joint; and at least one parameter (a) to the robot control module during welding, (b) to the welding control module during welding, and / or (c) to a sensor configured to acquire welding data during welding; and to store the weld strength and the location in memory.

[0009] In further features, the welding module is configured to determine the strength of the weld bead at the point along the joint, based on: the N distances at the point along the joint and a voltage applied to the welding machine during welding and received by the welding control module.

[0010] In other features, the welding module is configured to determine the strength of the weld bead at the point along the joint, based on: the N distances at the point along the joint and a current flowing through the welding machine during welding and received by the welding control module.

[0011] In further features, the welding module is configured to determine the strength of the weld bead at the point along the joint, based on: the N distances at the point along the joint and a feed rate of electrode material to the welding machine during welding, which is received by the welding control module.

[0012] In further features, the welding module is configured to determine the strength of the weld bead at the point along the joint, based on: the N distances at the point along the joint and a current from an electric motor configured to supply the electrode material to the welding machine during welding, which is received by the welding control module.

[0013] In further features, the welding module is configured to determine the strength of the weld bead at the point along the joint, based on: the N distances at the point along the joint and a volume flow of shielding gas to the welding machine during welding, which is received by the welding control module.

[0014] In further features, the welding module is configured to determine the strength of the weld bead at the point along the joint, based on: the N distances at the point along the joint and a position of the welding machine during welding, which is received by the robot control module.

[0015] In further features, the welding module is configured to determine the strength of the weld bead at the point along the joint, based on: the N distances at the point along the joint and a bearing or position of the welding machine during welding, which is received by the robot control module.

[0016] In further features, the welding module is configured to determine the strength of the weld bead at the point along the joint, based on: the N distances at the point along the joint and a direction of travel of the welding machine during welding, which is received by the robot control module.

[0017] In further features, the welding module is configured to determine the strength of the weld bead at the point along the joint, based on: the N distances at the point along the joint and a movement speed of the welding machine during welding, which is received by the robot control module.

[0018] In other features, the welding module is configured to determine the strength of the weld bead at the point along the joint, based on: the N distances at the point along the joint and the sound detected by a microphone during welding.

[0019] In further features, the welding module is configured to determine the strength of the weld bead at the point along the joint, based on: the N distances at the point along the joint and at least one image taken by a camera during welding.

[0020] In other features, the N positions are perpendicular to the connection.

[0021] The welding system also includes a robot in its other features.

[0022] The image sensor also includes a laser distance sensor.

[0023] In other features, the image sensor is positioned so that it follows behind the welding machine when the welding machine is moved along the joint during welding.

[0024] In further features, the welding module is configured to determine the strength of the weld bead at a point along the joint, based on: the N distances at the point along the joint and at least two parameters from (a) the robot control module during welding, (b) the welding control module during welding and / or (c) the sensor configured to acquire welding data during welding.

[0025] In further features, the welding module is configured to determine at least one other feature at the location along the joint, based on: the N distances at the location along the joint and at least one parameter from (a) the robot control module during welding, (b) the welding control module during welding and / or (c) the sensor configured to acquire welding data during welding.

[0026] Further characteristics include at least one other characteristic of at least one of the following: porosity of the weld bead at the location; whether a weld cut occurred at the location; whether joining took place at the location; whether the weld bead does not contain sufficient material at the location; and whether the weld bead contains excess material at the location.

[0027] In one feature, a method comprises: by means of a robot control module, actuating a robot and moving a welding machine along a joint of metal workpieces during welding, wherein the welding machine is attached to the robot; by means of a welding control module during welding, applying power to the welding machine, supplying shielding gas to the welding machine, and supplying electrode material to the welding machine; by means of an image sensor during welding, optically measuring N distances between the image sensor and N locations on an outer surface of a weld bead produced along the joint by the welding machine, wherein N is an integer greater than two;Determining the strength of the weld bead at a point along the joint, based on: the N distances at the point along the joint and at least one parameter from (a) the robot control module, (b) a welding control module during welding, and / or (c) a sensor configured to acquire weld data during welding; and storing the weld strength and the location strength in memory.

[0028] Further applications of the present invention will become apparent from the detailed description, the claims, and the drawings. The detailed description and the specific examples serve only for illustration and are not intended to limit the scope of the invention. Brief description of the drawings

[0029] The present invention is more fully understood from the detailed description and the accompanying drawings, wherein: Fig. Figure 1 is a functional block diagram of an exemplary arc welding system for metal; Fig. Figures 2-4 illustrate cross-sectional views of welds at overlapping joints of two workpieces; Fig. Figure 5 is a functional block diagram of an exemplary arc welding system; Fig. Figure 6 is a perspective view of an exemplary welding system with an exemplary welding gun; Fig. Figure 7 is a perspective view of an example welding system with an example welding gun; Fig. Figure 8 contains a cross-sectional view of workpieces welded together via a weld bead and a topographic profile of the weld bead, which was captured over time using an image sensor; Fig. Figure 9 shows an exemplary graphical representation of a distance over time while a weld bead is being produced; Fig. Figure 10 contains an exemplary representation of the topography of a weld bead as a function of increasing distance; Fig. 11 contains a functional block diagram of an exemplary implementation of a system for determining welding characteristics; Fig. Figure 12 contains an exemplary illustration of a model that generates the characteristics of a weld at a location based on inputs; and Fig. Figure 13 is a flowchart illustrating an exemplary procedure for monitoring arc welding.

[0030] Reference numerals can be reused in the drawings to identify similar and / or identical elements. Detailed description

[0031] Non-destructive testing (NDT) can be used to verify the integrity of arc welds. However, NDT is time-consuming and can damage parts. Non-destructive methods include surface-altering techniques such as dye penetrant testing, which is undesirable because the surface should not be altered before painting. Cracks in welds can impair subsequent processing of the joined components, such as painting. Cracks can also reduce the mechanical integrity of a joint. Cracks are stress concentration points that can cause premature failure of the joint under load. Furthermore, cracks can accelerate corrosion and lead to corrosion-related failure of the joint.

[0032] This application involves the use of an image sensor (e.g., a laser sensor) to non-destructively analyze a weld bead formed by arc welding. A welding module determines one or more characteristics of a weld at a specific location based on a profile / topography of the weld bead at that location, measured by the image sensor, and one or more other welding parameters.Examples of other welding parameters include, for example, a voltage applied during arc welding, a current through an electrode during arc welding, an electrode feed rate during arc welding, a current of an electric motor of an electrode feeder during arc welding, a volume flow of a shielding gas during arc welding, a position of a welding gun during arc welding, a position of the welding gun during arc welding, a direction of travel of the welding gun during arc welding, a movement speed of the welding gun during arc welding, sound recorded during arc welding, and an image captured by a camera during arc welding.Examples of characteristics include, for example, the porosity of the weld bead at that location, whether a cut has occurred at that location, whether a joining or bonding has taken place at that location, whether the weld bead does not contain sufficient material at that location, and whether the weld bead contains excess material at that location.

[0033] Fig. Figure 1 is a functional block diagram of an exemplary arc welding system for metal. Arc welding involves welding two or more workpieces, such as workpieces 104 and 108, together.

[0034] Workpieces 104 and 108 can be metallic workpieces or other suitable materials.

[0035] Power is supplied by means of a power supply 112 to generate an electric arc 114 between an electrode 116 and the workpieces 104 and 108. The heating by the electric arc 114 melts the (metal) electrode 116, and the molten metal 120 from the electrode 116 collects at the joint between the workpieces 104 and 108. The electrode 116 is moved along the joint between the workpieces 104 and 108 to create a weld bead. Once cooled, the metal 120 joins the workpieces 104 and 108 together. Although the example given is an overlap joint, this application is also applicable to butt joints, T-joints, and other types of joints.

[0036] However, different welding profiles (and cross-sections) create different stress distributions. Fig. Figures 2-4 illustrate cross-sectional views of welds at overlap joints of two workpieces 208 and 212. Fig. Figure 2 shows a first stress distribution through a first weld seam 204. Fig. Figure 3 shows a second stress distribution through a second weld 304. The second stress distribution across the weld is more uniform (and therefore better) than the first stress distribution. Fig. Figure 4 shows a third stress distribution through a third weld 404. The third stress distribution across the weld is more uniform (and therefore better) than the second stress distribution. The strength of the third weld 404 is therefore greater than the strength of the second weld 304, and the strength of the second weld 304 is greater than the strength of the first weld 204.

[0037] The present application involves optical measurement of the profile of a weld bead while welding workpieces is being carried out.

[0038] Based on the weld profile and one or more other parameters, the weld strength at points along the weld bead is determined in near real-time. These points along the weld bead can be identified based on their strength. For example, the weld can be identified as insufficient at a point if its strength (determined based on the weld profile and one or more process parameters) is lower than a predetermined strength.

[0039] Fig. Figure 5 is a functional block diagram of an exemplary arc welding system. A (gas-to-metal) welding gun 504 is mounted on a robot 508. Welding guns can also be referred to as arc welding equipment. The robot 508 moves the welding gun 504 along a joint or connection of workpieces to weld the workpieces together at the joint using the welding gun 504. A robot control module 512 controls the movement of the robot 508. For example, the robot control module 512 can control the robot 508 to achieve a target position (and orientation) of the welding gun 504, a target orientation of the welding gun 504, a target direction of travel of the welding gun 504, and a target speed of movement of the welding gun 504.

[0040] A welding control module 516 controls the process parameters during welding. The welding control module 516 controls the power supplied by a power supply 520 to one of the electrodes of the welding gun 504. For example, the welding control module 516 can control the voltage applied to the electrode and the current through the electrode. The welding control module 516 also controls the supply of electrode material to the welding gun 504 via an electrode feeder 524, which may contain a spool of electrode material. For example, the welding control module 516 can control the feed rate of the electrode to the welding gun 504 through the electrode feeder 524 and the current of a motor in the electrode feeder 524 that feeds the electrode of the welding gun 504. The welding control module 516 can also control the volume flow of the shielding gas to / through the welding gun 504.For example, the welding control module 516 can control the opening of a valve 528 to control the volume flow of shielding gas to / through the welding gun 504 from a shielding gas source 532.

[0041] An image sensor 550 is attached to the robot 508 or the welding gun 504 and moves with the welding gun 504. The image sensor 550 is positioned and configured to measure the profile of the weld bead produced by the welding gun 504 after the weld bead has been formed along the joint. The image sensor 550 measures the profile at a predetermined rate, such as every time the welding gun 504 has moved a predetermined distance along the joint, or at each predetermined time interval while the welding gun 504 is moving.

[0042] It may also include one or more other sensors 554. These other sensors 554 may include, for example, an acoustic sensor (e.g., a microphone), a video camera (e.g., a high-speed camera), thermography, a three-dimensional (3D) optical camera, and / or one or more other types of sensors. The one or more of these other sensors may be coupled to the robot 508 or the welding gun 504 and are configured to acquire parameters during welding.

[0043] Fig. Figure 6 is a perspective view of a welding system using an example of the 504 welding gun. A 604 electrode is shown in Fig. Figure 6 shows the electrode 604 and is supplied through the contact nozzle 608. The shielding gas flows into a cavity 612 and out through the nozzle 616. The electrode 604 also extends through the nozzle 616. Figure 620 illustrates exemplary workpieces that are butt-joined or joined by arc welding. Figure 624 illustrates the weld seam. Arrow 628 illustrates the direction in which the robot 508 moves the welding gun 504 to weld the workpieces 620 along the butt joint.

[0044] Fig. Figure 7 is a perspective view of an exemplary welding system, using an example of the 504 welding gun. Fig. Figure 7 also includes an example of the image sensor 550. Figure 702 illustrates a connection. As described above, the image sensor 550 can be mounted on the welding gun 504, for example, via a bracket 704. The image sensor 550 is positioned to optically measure the profile of the weld bead produced by the welding gun 504. The image sensor 550 travels behind the welding gun 504 in the direction of travel. Arrow 708 illustrates the direction of travel. Fig. 7.

[0045] The image sensor 550 includes a light source 712 configured to emit light 716 onto the weld bead produced by the welding gun 504. The light source 712 can, for example, comprise one or more lasers, one or more light-emitting diodes, or another suitable type of light source. The light source 712 is configured to emit light (e.g., only) along a plane perpendicular to the weld bead produced by the welding gun 504 (e.g., perpendicular to the direction of travel of the welding gun 504).

[0046] A light receiver 720 receives light reflected from the light source 712 through the weld bead at various points along the weld bead to the light receiver 720. The output of the light receiver 720 contains a topographic profile of the weld bead at the points above (perpendicular to) the weld bead.

[0047] Fig. Figure 8 shows a cross-sectional view of the workpieces 804 and 808 welded together via a weld bead 812 and distances used to generate a topographic profile of the weld bead 812, which is captured by the image sensor 550 over time.

[0048] As noted above, the light receiver 720 receives light from various points along the weld bead (perpendicular to it). Examples of these points are shown in Fig. Figure 8 is represented by 1, 2, 3, 4, 5, and 6. While the example shown is from location 6, the light receiver 720 can be configured to receive light from N locations along the weld bead, where N is an integer greater than or equal to 3. The light received from a location indicates a distance between the weld bead at that location and the light receiver 720. The distances at the locations can be used to generate weld bead topographies at the respective locations.

[0049] While the weld bead is being created and the image sensor 550 scans the weld bead, the light receiver 720 generates traces of the distances at the respective points. Fig. Figure 9 shows an exemplary graphical representation of a distance of 820 against a time of 824 while a weld bead is produced.

[0050] A trace 904 corresponds to the distance at the first position of the weld bead over time (i.e., at various points along the weld bead). A trace 908 corresponds to the distance at the second position of the weld bead over time. A trace 912 corresponds to the distance at the third position of the weld bead over time. A trace 916 corresponds to the distance at the fourth position of the weld bead over time. A trace 920 corresponds to the distance at the fifth position of the weld bead over time. A trace 924 corresponds to the distance at the sixth position of the weld bead over time. A set of distances at a given time specifies the topography of the weld bead at that time / location. For example, the distances (of traces 904-924) at time 928 correspond to the topography of the weld bead at location / time 928. Fig. 10 contains an exemplary illustration of the topography 1002 of a welding bead at time 928 as a function of an increasing distance 1004.

[0051] Fig. Figure 11 contains a functional block diagram of an exemplary implementation of a system for determining welding characteristics. A trigger module 1104 selectively generates a trigger signal during welding, such as at each predetermined time interval during welding or each time the welding gun 504 has moved a predetermined distance during welding. The predetermined time interval can be calibratable and may be, for example, 1 second or another suitable time interval. The predetermined distance can also be calibratable and may be, for example, 0.5 millimeters or another suitable distance.

[0052] Each time the trigger signal is generated, the welding control module 516 outputs a set of current welding parameters, and the robot control module 512 outputs a set of current robot parameters. The current welding parameters can include, for example, the current for the welding gun 504, the voltage applied to the welding gun 504, the current of a motor for the electrode feeder 524, the current feed rate of the electrode to the welding gun 504, and the volumetric flow rate of the shielding gas to the welding gun 504. The current robot parameters can include, for example, the current position of the welding gun (e.g., in a coordinate system of the workpieces being joined), the current orientation of the welding gun 504, the current direction of movement of the welding gun 504, and the current movement speed of the welding gun 504.

[0053] Each time the trigger signal is generated, a topography module 1108 creates a topography 1112 of the weld bead at a given location, based on the current distances at the respective points on the weld bead, measured by the light receiver of the image sensor 550. The topography 1112 contains the distances at the respective points. The topography 1112 can, for example, contain an equation (e.g., a polynomial equation) that specifies the profile of the outer surface of the weld bead at that point. The topography module 1108 can determine the equation, for example, using a curve-fitting algorithm and the distances measured by the light receiver.

[0054] Each time the trigger signal is generated, the sensors output 554 current external parameters. These current external parameters can include, for example, a current sound near the welding gun 504, a current image captured using a (e.g., high-speed) video camera, and / or other parameters.

[0055] Each time the trigger signal is generated, a welding module 1116 determines one or more characteristics (output(s)) of the weld bead at a location, based on the topography 1112 and at least one other parameter (inputs), such as: at least one of the current welding parameters; at least one of the current robot parameters; and / or at least one of the outputs of the sensors 554. Examples of characteristics include: whether a defect is present in the weld bead at the location, the length of a defect in the weld bead, the strength of the weld bead at the location, the porosity of the weld bead at the location, whether a cut has occurred at the location, whether the workpieces to be welded are joined or joined at the location, whether the weld bead at the location does not contain sufficient weld material from the electrode, and / or whether the weld bead at the location contains excess weld material from the electrode.

[0056] The welding module 1116, for example, can determine the use of a model that has been trained to generate the characteristics based on the inputs. The model could be, for example, a convolutional neural network, an artificial neural network, a model generated using genetic programming, or another suitable type of model. Fig. 12 contains an exemplary illustration of a model 1204 that generates the characteristics (outputs) 1208 relating to the weld at the location based on the inputs 1212 discussed above.

[0057] The welding module 1116 can, for example, determine the weld bead strength at a given location along the joint based on the distances (of the topography 1112) and the applied voltage. The welding module 1116 can determine the strength using an equation or a lookup table that relates the distances and applied voltages to the strength. As another example, the welding module 1116 can determine the weld bead strength at a given location along the joint based on the distances (of the topography 1112) and the current through the electrode. The welding module 1116 can determine the strength using an equation or a lookup table that relates the distances and currents to the strength.As another example, the welding module 1116 can determine the weld bead strength at a given location along the joint based on the spacing (of the topography 1112) and the electrode material feed rate. The welding module 1116 can determine the strength using an equation or a lookup table that relates the spacing and feed rates to the strength. As another example, the welding module 1116 can determine the weld bead strength at a given location along the joint based on the spacing (of the topography 1112) and the current of the electrode feed motor. The welding module 1116 can determine the strength using an equation or a lookup table that relates the spacing and currents to the strength.As another example, the welding module 1116 can determine the weld bead strength at a given location along the joint based on the distances (of the topography 1112) and the shielding gas flow rate. The welding module 1116 can determine the strength using an equation or a lookup table that relates the distances and shielding gas flow rates to the strength. As another example, the welding module 1116 can determine the weld bead strength at a given location along the joint based on the distances (of the topography 1112) and the position of the welding gun 504. The welding module 1116 can determine the strength using an equation or a lookup table that relates the distances and positions of the welding gun to the strength.As another example, the welding module 1116 can determine the weld bead strength at a given location along the joint based on the distances (of the topography 1112) and the movement speed of the welding gun 504. The welding module 1116 can determine the strength using an equation or a lookup table that relates the distances and speeds of the welding gun to the strength. As another example, the welding module 1116 can determine the weld bead strength at a given location along the joint based on the distances (of the topography 1112) and the position of the welding gun 504. The welding module 1116 can determine the strength using an equation or a lookup table that relates the distances and positions of the welding gun to the strength.As another example, the welding module 1116 can determine the weld bead strength at a point along the joint based on the distances (of the topography 1112) and the direction of travel of the welding gun 504. The welding module 1116 can determine the strength using an equation or a lookup table that relates the distances and welding gun directions to the strength. As another example, the welding module 1116 can determine the weld bead strength at a point along the joint based on the distances (of the topography 1112) and the sound picked up near the welding gun 504. The welding module 1116 can determine the strength using an equation or a lookup table that relates the distances and the sound (e.g., the magnitude(s) at one or more predetermined frequencies) to the strength.As another example, the welding module 1116 can determine the strength of the weld bead at the point along the joint based on the distances (of the topography 1112) and one or more features of one or more recorded images.

[0058] The welding module 1116 can perform one or more actions based on one or more characteristics. For example, the welding module 1116 can store information relating to one or more of the characteristics (e.g., along with the location) in memory 1120. Additionally or alternatively, the welding module 1116 can selectively activate one or more output devices 1124 to sound an alarm based on one or more of the characteristics. For example, the welding module 1116 can turn on a light, emit a sound through a speaker, activate a vibration device, display an alarm on a display device, or activate one or more other types of output devices.

[0059] Fig.Figure 13 is a flowchart illustrating an exemplary procedure for monitoring an arc welding process. The control begins when the arc welding of workpieces starts. At 1304, the welding module 1116 receives the current welding parameters. For example, the welding module 1116 receives the topography 1112, measurements from sensors 554, the current welding parameters, and the current robot parameters. The welding module 1116 also determines the current heat input at 1304. The welding module 1116 can determine the current heat input, for example, based on the current voltage applied and the current through the electrode. The welding module 1116 can determine the current heat input, for example, using an equation and / or a lookup table that relates voltages and currents to heat input.

[0060] At 1308, the welding module 1116 determines whether the current heat input is within a predetermined range. The predetermined range can be fixed or variable. It can also be calibratable and, for example, set to + / - a predetermined value of the average current heat input over a predetermined period. The predetermined value could, for example, be 3Σ of the average current heat input. If 1308 is false, the welding module 1116 generates an output at 1312, and the controller can proceed to 1328, which is discussed below. The welding module 1116 can, for example, store an insufficient heat input indicator and the current position in memory 1120 and / or activate one or more of the output devices 1124. If 1308 is true, the controller proceeds to 1316.

[0061] At 1316, the welding module 1116 determines the characteristics of the weld bead at the current location based on the topography 1112 and at least one of the other current parameters. For example, the welding module 1116 can determine the characteristics based on the topography 1112 and (a) at least one of the measurements from the sensors 554, (b) at least one of the current welding parameters, and / or (c) at least one of the current robot parameters.Examples of characteristics include: whether a defect is present in the weld bead at that location, the length of a defect in the weld bead, the strength of the weld bead at that location, the porosity of the weld bead at that location, whether a cut has occurred at that location, whether the workpieces to be welded are joined at that location, whether the weld bead does not contain sufficient weld material from the electrode at that location, and / or whether the weld bead contains excess weld material from the electrode at that location.

[0062] At 1320, the welding module 1116 determines whether the weld strength at the current location is within a predetermined range. The predetermined range can be fixed or variable. It can also be calibrated and set, for example, to + / - a predetermined value of a predetermined target strength. The predetermined value could, for example, be 3Σ of an average strength over a predetermined period. If 1320 is false, the welding module 1116 generates an output at 1324, and the control can continue at 1328, which is discussed below. For example, the welding module 1116 can store an indicator of the characteristics and the current location in memory 1120 and / or activate one or more of the output devices 1124. If 1320 is true, the control continues at 1328.

[0063] At value 1328, the welding module 1116 can determine whether the welding (or a weld bead analysis) is complete. For example, welding module 1116 can determine whether a predetermined time interval for a weld has elapsed since the welding began. If value 1328 is true, the control can terminate. If value 1328 is false, the control can return to value 1304 to obtain the current parameters for the next step.

[0064] Although the example above describes arc welding, the above can also be applied to other types of welding such as fusion welding and solid-state welding (such as laser welding, plasma welding, resistance welding, friction stir welding, etc.).

Claims

[1] Welding system comprising: a robot control module (512) configured to actuate a robot (508) and to move a welding device along a joint of metal workpieces during welding, the welding device being attached to the robot (508); a welding control module (516) configured to apply power to the welding machine, supply shielding gas to the welding machine and supply electrode material to the welding machine during welding; an image sensor (550) configured to optically measure N distances between the image sensor (550) and N locations on an outer surface of a weld bead produced along the joint by the welding machine during welding, where N is an integer greater than two; and a welding module (1116) configured for this purpose: to determine the strength of the weld bead at a point along the joint, based on: the N intervals at the point along the connection; and at least one parameter from (a) the robot control module (512) during welding, (b) the welding control module (516) during welding and / or (c) a sensor (554) configured to receive data from to capture welding during the welding process; and to store the strength of the weld and the location in the memory (1120). [2] Welding system according to claim 1, wherein the welding module (1116) is configured to determine the strength of the weld bead at the location along the joint, based on: the N intervals at the point along the connection; and a voltage that is applied to the welding machine during welding and received by the welding control module (516). [3] Welding system according to claim 1, wherein the welding module (1116) is configured to determine the strength of the weld bead at the location along the joint, based on: the N intervals at the point along the connection; and a current that flows through the welding machine during welding and is received by the welding control module (516). [4] Welding system according to claim 1, wherein the welding module (1116) is configured to determine the strength of the weld bead at the location along the joint, based on: the N intervals at the point along the connection; and a feed rate of electrode material to the welding machine during welding, which is received by the welding control module (516). [5] Welding system according to claim 1, wherein the welding module (1116) is configured to determine the strength of the weld bead at the location along the joint, based on: the N intervals at the point along the connection; and a current from an electric motor configured to supply the electrode material to the welding machine during welding, and received by the welding control module (516). [6] Welding system according to claim 1, wherein the welding module (1116) is configured to determine the strength of the weld bead at the location along the joint, based on: the N intervals at the point along the connection; and a volume flow of shielding gas to the welding machine during welding, which is received by the welding control module (516). [7] Welding system according to claim 1, wherein the welding module (1116) is configured to determine the strength of the weld bead at the location along the joint, based on: the N intervals at the point along the connection; and a position of the welding machine during welding, which is received by the robot control module (512). [8] Welding system according to claim 1, wherein the welding module (1116) is configured to determine the strength of the weld bead at the location along the joint, based on: the N intervals at the point along the connection; and a position of the welding machine during welding, which is received by the robot control module (512). [9] Welding system according to claim 1, wherein the welding module (1116) is configured to determine the strength of the weld bead at the location along the joint, based on: the N intervals at the point along the connection; and a direction of travel of the welding machine during welding, which is received by the robot control module (512). [10] Welding system according to claim 1, wherein the welding module (1116) is configured to determine the strength of the weld bead at the location along the joint, based on: the N distances at that point along the connection; and a movement speed of the welding machine during welding, which is received by the robot control module (516).

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