Welding systems and welding methods

Abstract

To provide a welding system and a welding method with which it is possible to achieve quality welding even when there is a gap or step at a butted portion of members to be welded.SOLUTION: A welding system performs work for butt-welding a butted portion where end faces of a first object member and a second object member are butted together. The welding system comprises a gap measurement unit that measures, as a gap distance, a minimum distance between a first end face and a second end face that form the butted portion, where the midpoint of the gap distance is set as a welding path.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a welding system and a welding method.

Background Art

[0002] A technique has been proposed in which end faces of two welded members to be welded are butt-welded using a welding robot to integrate the joined members. For example, in butt-welding using a welding robot, in order to correct displacement of the welding position with high precision, when the welding path is displaced from the set position, there is a technique of correcting so that the amount of displacement becomes zero and executing a welding operation (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the above technique does not assume a case where there are gaps or steps in the butting portion of the member to be welded. Since the width of the gap or step in the butting portion is not constant, there may be cases where welding is insufficient or welding defects such as deformation of the member due to welding occur.

[0005] The present invention has been made in view of such a background, and an object thereof is to achieve high-quality welding even when there are gaps or steps in the butting portion of the member to be welded.

Means for Solving the Problems

[0006] The main invention of the present invention for solving the above problems is a welding system that executes an operation of butt-welding a butting portion where end faces of a first target member and a second target member are butted together, The device includes a gap measuring unit that measures the shortest distance between the first end face and the second end face forming the butt joint as the gap distance. This welding system sets the midpoint of the aforementioned gap distance as the welding path.

[0007] Further issues and solutions disclosed in this application will be made clear in the section on embodiments of the invention and in the drawings. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a welding system and welding method that can achieve high-quality welding even if there are gaps or steps in the butt joint of the members to be welded. [Brief explanation of the drawing]

[0009] [Figure 1] A diagram showing an example of the overall configuration of a welding system 100 according to one embodiment of the present invention. [Figure 2] This figure shows how a welding target member is measured using the welding system 100 according to this embodiment. [Figure 3] This figure shows the welding process of a member to be welded using the welding system 100 according to this embodiment. [Figure 4] A diagram showing an example of the hardware configuration of terminal 1. [Figure 5] A diagram showing an example of the functional configuration of terminal 1. [Figure 6] This figure shows an example of condition data stored by the torch position / angle condition storage unit according to this embodiment. [Figure 7] This figure shows an example of a control flowchart for the welding system according to this embodiment. [Figure 8] This figure shows an example of specifying P1-P4 at arbitrary positions between the first end face 201a and the second end face 202a. [Figure 9] This figure shows an example of detecting the ends of the first and second target members 201 and 202, respectively. [Figure 10] A diagram showing an example of creating multiple reference lines 250. [Figure 11]A figure showing a partially enlarged view of FIG. 10. [Figure 12] A figure showing a state of detecting a step. [Figure 13] A figure showing an example of resetting the welding path 200a by connecting the midpoints generated by the welding path generation unit 105. [Figure 14] A figure showing an overall configuration example of the welding system 1000 according to another embodiment of the present invention. [Embodiment for Carrying Out the Invention]

[0010] The contents of the embodiments of the present invention will be listed and described. The present invention has, for example, the following configuration.

[0011] [Item 1] A welding system that performs a butt welding operation on a butted portion where the end faces of a first target member and a second target member are abutted, comprising a gap measurement unit that measures the shortest distance between the first end face and the second end face forming the butted portion as a gap distance, and a welding system that sets the midpoint of the gap distance as a welding path. [Item 2] In the welding system according to Item 1, a welding system that changes at least one of the position of the welding torch and the angle of the welding torch according to the gap distance. [Item 3] In the welding system according to Item 2, the gap measurement unit measures the inclination of the gap surface formed by connecting the first end face and the second end face with respect to the surface on which the first target member and the second target member are placed, and a welding system that changes at least one of the position of the welding torch and the angle of the welding torch according to the inclination. [Item 4] In the welding system according to Item 3, a welding system that adjusts the angle of the welding torch to be perpendicular to the gap surface. [Item 5] In a welding system described in any one of items 2 through 4, If the gap distance is greater than a first threshold and less than a second threshold greater than the first threshold, the angle of the welding torch and at least one of the welding torch are changed. A welding system that, when the gap distance exceeds the second threshold, stops the operation or notifies the user that the gap distance is large. [Item 6] In the welding system described in item 1, The system further includes a point cloud data acquisition unit that acquires three-dimensional point cloud data of the first target member and the second target member, The gap measurement unit is a welding system that measures the gap distance from two-dimensional point cloud data of the cross-sections of the first and second end faces of the acquired three-dimensional point cloud data. [Item 7] A welding method using a system that performs butt welding of a joint where the end faces of a first target member and a second target member are joined together, The shortest distance between the first end face and the second end face forming the butt joint is measured as the gap distance. A welding method in which the midpoint of the aforementioned gap distance is set as the welding path.

[0012] <Details of the embodiment> A specific example of a welding system 100 according to one embodiment of the present invention will be described below with reference to the drawings. However, the present invention is not limited to these examples, and is intended to include all modifications within the meaning and scope of the claims, as indicated by the claims. In the following description, identical or similar elements in the accompanying drawings are given the same or similar reference numerals and names, and redundant descriptions of identical or similar elements in the description of each embodiment may be omitted. Furthermore, features shown in each embodiment are applicable to other embodiments, provided they do not contradict each other.

[0013] Figure 1 shows an example of the welding system 100 of this embodiment. As shown in Figure 1, the welding system 100 of this embodiment includes a terminal 1, a work robot 2, and a controller 3. The work robot 2 has at least an arm 21, a sensor 22, and a welding torch 23. The terminal 1, controller 3, and work robot 2 are connected to each other via wired or wireless means so that they can communicate with one another.

[0014] Figure 2 shows how the welding path 200 is set using the working robot 2 of the welding system 100. The welding path 200 is a pre-set route for welding, and in this embodiment, it is set to follow approximately along the X-axis direction to the midpoint of the butt joint 203 formed by bringing the end faces 201a and 202a of the first target member 201 and the second target member 202 together in the Y-axis direction. In this embodiment, point cloud data of the surface and end face shapes near the butt joint 203 of the two target members 201 and 202 is acquired by a sensor 22 provided on the arm 21 of the working robot 2, and high-quality welding is achieved by resetting the welding path if there are gaps or steps in the butt joint 203 based on this point cloud data.

[0015] Figure 3 shows the welding process performed on a reset welding path 200a using the working robot 2 of the welding system 100. The target position and target angle of the welding torch are determined according to the shape information of the reset welding path 200a, and the working robot 2 controls the movement of the arm 21 so that the welding torch 23 is at the target position and target angle, and performs the welding operation along approximately the X-axis direction.

[0016] <Terminal 1> Figure 4 shows the hardware configuration of terminal 1. Terminal 1 may be a general-purpose computer such as a personal computer, or it may be logically implemented through cloud computing. Note that the illustrated configuration is just one example, and other configurations are possible. For example, some functions provided on the processor 10 of terminal 1 may be executed by an external server or another terminal.

[0017] Terminal 1 comprises at least a processor 10, memory 11, storage 12, a transceiver 13, an input / output unit 14, etc., which are electrically connected to each other via a bus 15.

[0018] The processor 10 is a computing device that controls the operation of the entire terminal 1, controls the transmission and reception of data with at least the work robot 2, and performs information processing necessary for application execution and authentication processing. For example, the processor 10 is a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), or both a CPU and a GPU, and executes programs for this system stored in the storage 12 and loaded into the memory 11 to perform various information processing tasks.

[0019] Memory 11 includes main memory composed of volatile storage devices such as DRAM (Dynamic Random Access Memory) and auxiliary memory composed of non-volatile storage devices such as flash memory and HDD (Hard Disk Drive). Memory 11 is used as a work area for the processor 10, and also stores the BIOS (Basic Input / Output System) executed when terminal 1 starts up, as well as various setting information.

[0020] Storage 12 stores various programs, such as application programs. A database containing data used for each process may also be built on storage 12.

[0021] The transmitting / receiving unit 13 connects terminal 1 to at least the work robot 2 and the work robot 2, and transmits and receives data, etc., according to the instructions of the processor. The transmitting / receiving unit 13 is configured by wire or wireless connection, and if it is wireless, it may be configured by, for example, a short-range communication interface such as WiFi, Bluetooth®, and BLE (Bluetooth Low Energy).

[0022] The input / output unit 14 is composed of, for example, an information output device (e.g., a display) and an information input device (e.g., a keyboard and mouse) if the terminal 1 is a personal computer, and an information input / output device such as a touch panel if it is a smartphone or tablet terminal.

[0023] Bus 15 is connected in common to all of the above elements and transmits, for example, address signals, data signals, and various control signals.

[0024] <Working Robot 2> Returning to Figure 1-3, the work robot 2 according to this embodiment will be described.

[0025] As described above, the work robot 2 has an arm 21, a sensor 22, and a welding torch 23. Note that the illustrated configuration is an example and is not limited to this configuration.

[0026] The arm 21's movements are controlled by the terminal 1 based on a three-dimensional robot coordinate system. The arm 21 may also be further equipped with a controller 3 connected to the work robot 2 by wire or wireless, which controls its movements.

[0027] Sensor 22 senses the first and second target members 201 and 202 based on a three-dimensional sensor coordinate system. Sensor 22 is, for example, a laser sensor that operates as a three-dimensional scanner. Through sensing, it acquires three-dimensional point cloud data of the vicinity of the butt joint 203, including the first end face 201a and the second end face 202a that form the butt joint 203. From the acquired three-dimensional point cloud data of the cross-section of the first end face 201a and the second end face 202a, it measures the gap distance n, which is the shortest distance between the first end face 201a and the second end face 202a. A line connecting the midpoint point data along approximately the X-axis direction is set as the welding path 200. In the three-dimensional point cloud data, for example, each point data has coordinate information of the sensor coordinate system, making it possible to understand the shape of the object to be inspected from the point cloud.

[0028] Sensor 22 is not limited to a laser sensor; for example, it may be an image sensor using a stereo system, or it may be a sensor independent of the measurement robot, as long as it can acquire coordinate information in a three-dimensional sensor coordinate system. Furthermore, to make the explanation more concrete, a configuration using three-dimensional point cloud data will be described below as an example.

[0029] Furthermore, a predetermined calibration may be performed before operation to associate the robot coordinate system and the sensor coordinate system with each other. For example, the system may be configured so that the user specifies a position (coordinate) based on the sensor coordinate system, and the arm 21 and sensor 22 are controlled based on the corresponding position.

[0030] The welding torch 23 performs welding on a welding path 200a set approximately along the X-axis direction at the butt joint 203 of the first and second target members 201 and 202, based on a three-dimensional sensor coordinate system. The welding torch 23 is a tool used in fusion welding methods such as arc welding, laser welding, electron beam welding, and plasma arc welding, and outputs an arc, laser, beam, etc. from the welding torch 23 to melt the first and second target members 201 and 202, thereby welding the first and second target members 201 and 202. The welding torch 23 may also be a discharge unit for filler material (adhesive) used in brazing, or a discharge unit for sealing material or adhesive.

[0031] Furthermore, a predetermined calibration may be performed before operation to associate the working robot 2, its robot coordinate system, and the torch coordinate system with each other. For example, the system may be configured so that the arm 31 and welding torch 23 are controlled based on the corresponding position when the user specifies a position (coordinate) based on the torch coordinate system.

[0032] <Functions of Terminal 1> Figure 5 is a block diagram illustrating the functions implemented in terminal 1. In this embodiment, the processor 10 of terminal 1 includes a welding condition setting unit 101, a point cloud data acquisition unit 102, a gap measurement unit 103, a welding torch position and angle determination unit 104, a movement path generation unit 105, and a welding execution unit 106. The storage 12 of terminal 1 includes a welding condition storage unit 121, a three-dimensional CAD data storage unit 122, a measured point cloud data storage unit 123, and a torch position and angle condition storage unit 124.

[0033] The welding condition setting unit 101 receives information input from the user regarding the first and second target members 201 and 202 via the input / output unit 14 of terminal 1. For example, the user selects and inputs information such as the material and shape of the members to be welded. The input information is stored in the welding condition storage unit 121.

[0034] The welding condition setting unit 101 can also input welding types from linear welding, which generates a linear welding path by continuously performing welding operations while moving the welding torch 23, and spot welding, which performs welding operations while the welding torch 23 is stationary. In addition, it can set and input welding paths for CAD data of the welding target member stored in the three-dimensional CAD data storage unit 122. Furthermore, it can set and input the position for gap measurement, which will be described later, for the welding path. The input welding type, welding path, and gap measurement position information are stored in the welding condition storage unit 121.

[0035] The point cloud data acquisition unit 102, upon instruction from terminal 1, for example, controls the work robot 2 and operates the arm 21 and sensor 22 to acquire three-dimensional point cloud data of the butt joint 203, which includes the first end face 201a and the second end face 202a of the first and second target members 201 and 202, including a preset welding path 200. The operation of the arm 21 and sensor 22 is preset so that three-dimensional point cloud data of the butt joint 203 can be acquired. The acquired three-dimensional point cloud data is, for example, three-dimensional coordinate information data based on the sensor coordinate system and is stored in the measurement point cloud data storage unit 123.

[0036] The gap measurement unit 103 measures the shortest distance (gap distance) between the first end face 201a of the first target member 201 and the second end face 202a of the second target member 202, based on the acquired point cloud data, the information from the welding condition storage unit 121, and, if necessary, the information from the three-dimensional CAD data storage unit 122. The detailed method of gap measurement will be described later.

[0037] As shown in Figure 6, the welding torch position / angle condition storage unit 124 stores information on the position and angle of the welding torch 23, as well as information on whether welding is appropriate. For example, if the gap distance n is smaller than the first threshold (Th1), the position and angle of the welding torch 23 remain unchanged from their predetermined positions and angles (θ1), respectively. If the gap distance n is greater than the first threshold (Th1) and less than the second threshold (Th2), the position of the welding torch 23 is shifted from its predetermined position to the positive side in the Y-axis direction (the torch angle remains unchanged from its predetermined angle). If the gap distance n is greater than the second threshold (Th2), it is determined that welding is not possible, and an error notification indicating that welding should not be performed is sent via the input / output unit 14, and the execution of the welding operation is prohibited.

[0038] Furthermore, as shown in Figure 6, if there is a step (a displacement in the Z-axis direction) on the upper surfaces of the first target member 201 and the second target member 202, the welding torch position and angle determination unit 104 determines the position and angle of the welding torch 23 relative to the gap surface GS at the gap measurement position, based on information regarding the gap surface GS (see Figure 12) formed by connecting the first end face 201a and the second end face 202a, the inclination (θ2) with respect to the surface on which the first and second target members 201 and 202 are placed (in the Y-axis direction in Figure 12), and the information from the torch position and angle condition storage unit 124. For example, if the inclination (θ2) is less than the third threshold (Th3), the position and angle of the welding torch 23 remain unchanged from their predetermined positions and angles (θ3). If the inclination (θ2) is greater than the third threshold (Th3) and less than the fourth threshold (Th4), the angle of the welding torch 23 is increased beyond the predetermined angle. If the inclination (θ2) is greater than the fourth threshold (Th4), the system determines that welding is impossible due to the large step difference and sends an error notification via the input / output unit 14 indicating that welding should not be performed, and prohibits the execution of the welding operation. In this case, it is preferable to adjust the angle of the welding torch 23 relative to the gap surface GS to be perpendicular to the gap surface GS in order to improve welding quality.

[0039] The movement path generation unit 105 generates a movement path for the welding torch 23 based on the determined position and angle of the welding torch 23 at the gap measurement position. When determining the position and angle of the welding torch 23 for multiple gap measurement positions, the unit generates a movement path such that the determined position and angle of the welding torch 23 are for each of those multiple positions.

[0040] The welding execution unit 106 controls the work robot 2 based on the generated movement path to perform the welding operation.

[0041] As described above, the welding condition storage unit 121 stores information such as the material and shape of the welding target member, welding type, welding path 200, and gap measurement position, which are entered and set in the welding condition setting unit 101. The stored information is not limited to information entered by the user via the welding condition setting unit 101, but may also include information registered in the system in advance or information automatically determined by the system based on predetermined rules.

[0042] The three-dimensional CAD data storage unit 122 stores information such as the material and shape of the first and second target members 201 and 202, welding path information, and plate thickness (thickness in the Z-axis direction) information of the first and second target members 201 and 202.

[0043] The measurement point cloud data storage unit 123 stores the point cloud data acquired by the point cloud data acquisition unit 102.

[0044] <Control Flow> Figure 7 shows the overall control flow of the welding system 100. First, the welding condition setting unit 101 determines the welding conditions, etc. (step 101). In this step, the welding condition setting unit 101 receives information from the user via the input / output unit 14 of terminal 1 regarding the welds of the members to be welded 201 and 202, the input welding type, the welding path 200, and the gap measurement position. This information does not necessarily need to be input by the user and may be pre-registered in the system.

[0045] Next, the point cloud data acquisition unit 102 acquires three-dimensional point cloud data (step 102). In this step, based on the information about the welding path 200 input in step 101 or set in advance, the working robot 2 is controlled to acquire three-dimensional point cloud data of the butt joint 203 including the first end face 201a and the second end face 202a of the first and second target members 201 and 202, including the set welding path 200. Next, the gap measurement unit 103 performs gap measurement (step 103). In this step, the gap measurement unit 103 measures the shortest distance (gap distance) between the first end face 201a and the second end face 202a based on the measured three-dimensional point cloud data, and sets the welding path 200a by connecting the midpoints. This will be explained in more detail below.

[0046] Figure 8-13 shows an example of resetting the welding path when there is a gap or step in the butt joint 203, which includes the first end faces 201a and the second end faces 202a of the first and second target members 201 and 202. First, as shown in Figure 8, when there is a gap G of gap distance n between the first end face 201a and the second end face 202a, first, P1 is specified at an arbitrary position on the first end face 201a of the first target member 201, and P2 is specified at an arbitrary position on the second end face 202a of the second target member 202, with the gap G in between. Also, P3 and P4 are specified on the positive and negative sides in the X-axis direction of the first end face 201a, respectively, with P1 in between.

[0047] Next, as shown in Figure 9, point cloud search is performed by scanning the operating spheres 230 and 240 along the X-axis direction, using the specified P1 and P2 as reference points, on the positive and negative sides of the X-axis direction, to detect the ends of the first and second target members 201 and 202, respectively. Here, the radius of each operating sphere (SearchRadius) 230 from P1 is SearchRadiusV, and the spacing between the operating spheres 230 is PitchV. Similarly, the radius of each operating sphere 240 from P2 is SearchRadiusV, and the spacing between the operating spheres (SearchRadius) 240 is PitchV. Scanning is performed on the positive and negative sides of the X-axis direction, respectively, until point cloud data (two-dimensional) on the cross-sectional plane can no longer be acquired. These points are defined as the first ends 203a and 204a, and the second ends 203b and 204b, respectively.

[0048] Next, as shown in Figure 10, the gap measurement unit 103 connects corresponding spheres with a straight line across the gap G between the operating spheres 230 and 240, creating a plurality of reference lines 250 that will form the cross-section of the welding path. At this time, pairs of spheres 230 and 240 are connected such that they are the shortest distances between the point clouds within each operating sphere (SearchRadius) 230 and 240, that is, the point clouds within the SearchRadius are the shortest distances between them, and the shortest distance between the first end face 201a of the first target member 201 and the second end face 202a of the second target member 202 is obtained as the gap distance n.

[0049] Figure 11 is a magnified view of a portion of Figure 10. Here, the reference line 250 created in Figure 10 is further divided. As shown in Figure 11, the circular region is scanned along the reference line 250 (the line segment between positions P1 and P2) created in Figure 10, with each operating sphere 260 having a radius of SearchRadiusU and an arrangement interval of PitchV, on both the positive and negative sides in the Y-axis direction, and the midpoint is searched for for each reference line 250.

[0050] Figure 12 shows how a step is detected using the centroid position of the points on the control sphere 260 in Figure 11. As shown in Figure 12, if there is a step between the upper surfaces of the first target member 201 and the second target member 202, for example, in Figure 12, the control sphere 260 is scanned to calculate the midpoint C of the line segment 280 connecting the endpoints 201b and 202b of the end faces 201a and 202a, respectively, from which the point cloud 270 can no longer be acquired. Here, because the change in the centroid position of the points on the control sphere 260 is large, the difference in height in the Z-axis direction is detected as a step.

[0051] Next, the welding torch position and angle determination unit 104 determines the welding position and angle of the welding torch 23 (step 104). In this step, the welding torch position and angle determination unit 104 determines the position and angle of the welding torch 23, as well as the welding suitability, based on the information on the torch position and angle corresponding to the gap distance and shape type, and the welding suitability information stored in the torch position and angle condition storage unit 124, and also determines the welding suitability, and notifies the user of the welding suitability determination result.

[0052] For example, as shown in Figure 6, the welding torch position and angle condition storage unit 124, for example, if the gap distance n is less than the first threshold (Th1), does not change the position and angle of the welding torch 23 from their predetermined positions and angles (θ1), respectively. If the gap distance n is greater than the first threshold (Th1) and less than the second threshold (Th2), it shifts the position of the welding torch 23 from its predetermined position to the positive side in the Y-axis direction (the torch angle does not change from its predetermined angle). If the gap distance n is greater than the second threshold (Th2), it determines that welding is not possible and sends an error notification via the input / output unit 14 indicating that welding should not be performed, and prohibits the execution of the welding operation.

[0053] Furthermore, as shown in Figure 12, if there is a step (a displacement in the Z-axis direction) on the upper surfaces of the first target member 201 and the second target member 202, the welding torch position / angle determination unit 104 determines the position and angle of the welding torch 23 relative to the gap surface GS at the gap measurement position, based on information regarding the inclination (θ2) with respect to the gap surface GS formed by connecting the first end face 201a and the second end face 202a, and the surface on which the first and second target members 201 and 202 are placed (in the Y-axis direction in Figure 12), as well as the information from the torch position / angle condition storage unit 124. For example, if the inclination (θ2) is less than the third threshold (Th3), the position and angle of the welding torch 23 remain unchanged from their predetermined positions and angles (θ3). If the inclination (θ2) is greater than the third threshold (Th3) and less than the fourth threshold (Th4), the angle of the welding torch 23 is increased beyond the predetermined angle. If the inclination (θ2) is greater than the fourth threshold (Th4), the system determines that welding is impossible due to the large step difference and sends an error notification via the input / output unit 14 indicating that welding should not be performed, and prohibits the execution of the welding operation. In this case, it is preferable to adjust the angle of the welding torch 23 relative to the gap surface GS to be perpendicular to the gap surface GS in order to improve welding quality.

[0054] Next, as shown in Figure 13, the welding path 200a is generated by connecting the midpoints generated by the welding path generation unit 105 (step 105). In this step, the welding path generation unit 105 is set to be approximately aligned with the X-axis direction and generates a welding path 200a defined by the movement route and angle of the welding torch 23, based on the position and angle of the welding torch 23. Here, the welding path 200a can also be defined by a movement route defined only by the position of the welding torch 23.

[0055] Finally, welding is performed by the welding execution unit 106 (step 106). In this step, the movement of the arm of the working robot 2 and the welding torch 23 is controlled based on the welding path 200a generated by the welding path generation unit to perform welding along the direction of travel.

[0056] As described in the embodiment, by setting the welding path in the center of the gap, it becomes possible to generate a welding path even if the gap is not on a flat plane. Furthermore, welding in the center of the gap allows for welding with minimal resource and energy input. In addition, it becomes easy to change the welding conditions according to the extracted gap amount. As a result, even if there are gaps or steps in the butt joint of the parts to be welded, and the width of the gaps or steps is not constant, welding can be performed with high work accuracy, thereby improving the quality of the weld.

[0057] Although these embodiments have been described above, they are intended to facilitate understanding of the present invention and are not intended to limit its interpretation. The present invention can be modified and improved without departing from its spirit, and equivalents thereof are also included.

[0058] For example, in Figure 1, the welding system 100 of this embodiment was configured such that the working robot 2 was equipped with both a sensor 22 and a welding torch 23. However, it is also possible to have a configuration that includes a measuring robot equipped with a sensor and a welding robot equipped with a welding torch.

[0059] Figure 14 shows an example of the overall configuration of a welding system 1000 according to another embodiment of the present invention. As shown in Figure 14, the welding system 1000 of this embodiment includes a terminal 1, a measuring robot 2000, a welding robot 3000, and a controller 3. The measuring robot 2000 has at least an arm 2100 and a sensor 2200 mounted on the tip of the arm 2100. The welding robot 3000 has at least an arm 3100 and a welding torch 3200 mounted on the tip of the arm 3100. The terminal 1 and the controller 3 are connected to the measuring robot 2000 and the welding robot 3000, respectively, so that they can communicate with each other by wired or wireless means.

[0060] In this embodiment, a sensor 2200 provided on the arm 2100 of the measuring robot 2000 acquires point cloud data of the surface and end face shapes near the butt joint 203 of the two target members 201 and 202 shown in Figure 2. Based on this point cloud data, the welding path is reset if there is a gap or step in the butt joint 203. Then, the target position and target angle of the welding torch are determined according to the shape information of the reset welding path 200a, and the welding robot 3000 controls the movement of the arm 3100 so that the welding torch 3200 is at the target position and target angle, and performs the welding work along approximately the X-axis direction.

[0061] Furthermore, when calculating the midpoint in the above-described embodiment, the midpoint may be calculated by, for example, extracting the midpoint of the line segment 280 connecting the endpoints 201b and 202b in Figure 12, and detecting the difference in height along the Z-axis.

[0062] Furthermore, although the above-described embodiment shows an example where the energy during welding is constant, it is also possible to set the energy to change according to the gap distance. In this case, further improvement in quality can be expected.

[0063] In the embodiments described above, an example of applying the present invention to a welding system that uses a robotic arm for welding was explained. However, the present invention is not limited to welding applications and can also be applied to welding systems that perform sealing or bonding operations on the butt joints of two members. In such cases, the welding torch can be replaced with a dispensing unit that dispenses sealant or adhesive. [Explanation of Symbols]

[0064] 1 Terminal, 2 Work robot, 3 Controller, 10 Processor, 11 Memory, 12 Storage, 13 Transmitter / Receiver, 14 Input / Output Unit, 15 Bus, 21 Arm, 22 Sensor, 23 Welding Torch, 100, 1000 Welding System, 101 Welding Condition Setting Unit, 102 Point Cloud Data Acquisition Unit, 103 Gap Measurement Unit, 104 Welding Torch Position / Angle Determination Unit, 105 Movement Path Generation Unit, 106 Welding Execution Unit, 121 Welding Condition Storage Unit, 122 Three-Dimensional CAD Data Storage Unit, 123 Measurement Point Cloud Data Storage Unit, 124 Torch Position / Angle Condition Storage Unit, 200, 200a Welding Path, 201 First Target Member, 201a First End Face, 201b First Endpoint, 202 Second Target Member, 202a Second End Face, 202b Second Endpoint, 203 Butt joint, 203a, 204a; First end, 203b, 204b; Second end, 230, 240, 260; Operating sphere, 250; Reference line, 270; Point cloud, 280; Line segment, 2000; Measuring robot, 3000; Welding robot, G; Gap, GS; Gap surface, n; Gap distance, C; Midpoint

Claims

1. A welding system that performs butt welding of a joint where the end faces of a first target member and a second target member are joined together, The device includes a gap measuring unit that measures the shortest distance between the first end face and the second end face forming the butt joint as the gap distance. The midpoint of the aforementioned gap distance is set as the welding path, Depending on the gap distance, at least one of the position of the welding torch and the angle of the welding torch is changed. The gap measuring unit measures the inclination between the gap surface formed by connecting the first end face and the second end face and the surface on which the first target member and the second target member are placed. A welding system that changes at least one of the position of the welding torch and the angle of the welding torch according to the aforementioned inclination.

2. In the welding system according to claim 1, A welding system that adjusts the angle of the welding torch to be perpendicular to the gap surface.

3. In the welding system according to claim 1 or claim 2, If the gap distance is greater than a first threshold and less than a second threshold that is greater than the first threshold, change at least one of the angle of the welding torch and the position of the welding torch. A welding system that, when the gap distance exceeds the second threshold, stops the operation or notifies the user that the gap distance is large.

4. In the welding system according to claim 1, The system further includes a point cloud data acquisition unit that acquires three-dimensional point cloud data of the first target member and the second target member, The gap measurement unit is a welding system that measures the gap distance from two-dimensional point cloud data of the cross-sections of the first and second end faces of the acquired three-dimensional point cloud data.

5. A welding method using a system that performs butt welding of a joint where the end faces of a first target member and a second target member are joined together, The shortest distance between the first end face and the second end face forming the butt joint is measured as the gap distance. The midpoint of the aforementioned gap distance is set as the welding path, Depending on the gap distance, at least one of the position of the welding torch and the angle of the welding torch is changed. The gap surface formed by connecting the first end face and the second end face, and the inclination with respect to the surface on which the first target member and the second target member are placed are measured. A welding method comprising changing at least one of the position of the welding torch and the angle of the welding torch according to the aforementioned inclination.

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