Welding systems and welding methods

Abstract

This welding system provides a mechanism that does not require teaching, easily creates a planned trajectory for the welding torch based on a 3D model, and automatically performs welding work using a welding robot based on the created planned trajectory and the shape of the part to be welded detected during welding. [Solution] The welding system 9 includes a welding robot 21 having a robot arm 23, a welding torch 25 positioned at the tip of the robot arm 23, and a measurement sensor 27 for measuring the position and shape of the part of the object to be welded; a trajectory creation unit 51 that creates a planned trajectory 47 of the welding torch 25 based on a 3D model 42 of the object to be welded; and a control unit 31 having an operation unit 33 that drives the welding robot 21 along the planned trajectory 47, and a correction unit 35 that corrects the planned trajectory 47 based on the measured position and shape of the part to be welded.

Description

Technical Field

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

Background Art

[0002] There is known a welding robot that creates a reference welding program by an instruction operation for a workpiece, and welds the welding positions of a plurality of workpieces of the same type by welding means based on this reference welding program (JP2011-45898A, hereinafter referred to as Patent Document 1).

Summary of the Invention

Problems to be Solved by the Invention

[0003] According to the welding robot of Patent Document 1, the welding program is corrected and welded based on a reference image and an image during welding. As a result, the amount of displacement of the workpiece with respect to the welding program is corrected. However, still, an operator needs to teach the robot in advance to create a reference welding program. Teaching the robot requires actually moving the robot to acquire coordinates, creating an operation program accordingly, and performing an operation check, which is a troublesome task. An object of the present invention is to automatically execute a welding operation by a welding robot without requiring a teaching operation, easily creating a planned movement locus of a welding torch based on a 3D model, and according to the created planned movement locus and the shape of a welded object part detected during welding.

Means for Solving the Problems

[0004] A first aspect of the present invention is a welding robot comprising a robot arm, a welding torch disposed at the tip of the robot arm, a measurement sensor disposed at the tip of the robot arm for measuring the position and shape of a welded part of a welding object, and having a welding robot, A trajectory creation unit creates a planned trajectory for the welding torch based on a 3D model of the part to be welded, A control unit that operates the welding robot to weld the part to be welded, An operating unit that operates the welding robot along the aforementioned planned movement trajectory, A correction unit corrects the planned movement trajectory based on the position and shape of the part to be welded measured by the measurement sensor, A control unit having, This is a welding system that has the following features.

[0005] A second aspect of the present invention is, A welding method using a welding robot, On the 3D model of the object to be welded, specify the welding start point and welding end point. The trajectory creation unit creates the planned trajectory of the welding torch based on the type and shape of the object to be welded. The welding robot moves the welding torch based on the planned movement trajectory. As the welding torch moves, the measuring sensor positioned adjacent to the welding torch continuously measures the shape of the part of the object to be welded and the distance between the part to be welded and the welding torch. Based on the measured shape, distance, and type, the welding robot supplies energy to the welding torch while correcting the position of the welding torch, and the welding torch welds the part to be welded. The system records the actual trajectory of the welding torch as it moves. This is a welding method.

[0006] A welding robot may have an energy source, a shielding gas source, and a wire supply device. Welding methods include, for example, laser welding and arc welding. Arc welding methods include, for example, shielded metal arc welding and gas-shielded arc welding. Gas-shielded arc welding methods include, for example, TIG welding, MIG welding, CO2 welding, and MAG welding. The energy source is selected according to the welding method. Energy sources include, for example, a laser oscillator and a welding power supply. Output refers to the amount of energy output by the energy source and its waveform. A welding robot may also have a shielding gas source and a gas regulator. The gas regulator controls the gas flow rate. Robot arms include, for example, vertical articulated robots, horizontal articulated robots, parallel link robots, orthogonal axis robots, and robots that utilize Scott-Russell linkage mechanisms. Measurement sensors include, for example, cameras, laser rangefinders, and ultrasonic testing sensors. The measurement sensors may include multiple types of sensors. They may also include sensors for detecting pre-welding locations and inspection sensors.

[0007] The trajectory creation unit may consist of, for example, a personal computer, a workstation, or a portable information terminal. Part or all of the trajectory creation unit may be included in a factory network server or a cloud server. The trajectory creation unit may search the execution data for 3D models similar to the 3D model to be welded. The trajectory creation unit reads the execution trajectory, welding condition table, and score corresponding to the similar 3D model found in the execution data from the storage unit. The trajectory creation unit may create a planned movement trajectory based on the data of the similar 3D model read from the storage unit and the 3D model to be welded. The memory unit, the trajectory creation unit, and the control unit are connected to each other by means of a bus, intranet, internet, or dedicated line, for example. The trajectory creation unit may include a condition matching unit. The condition matching unit modifies the welding conditions based on the execution data.

[0008] The control unit is, for example, a personal computer, a workstation, or a robot controller. The control unit is usually located close to the welding robot. The operating unit may include a numerical control unit and a sequence control unit. The operating unit numerically controls the robot arm. The operating unit controls the welding equipment. The operating unit may have a welding energy output adjustment unit and a gas adjustment unit. The output adjustment unit controls the energy source. The gas adjustment unit controls the gas regulator.

[0009] The memory unit includes main memory and external memory. Part or all of the memory unit may be located separately from the control unit. Part or all of the memory unit may also be included in a factory network server or a cloud server. The planned movement trajectory may include the attitude and position of the welding torch relative to the part to be welded, as well as its movement speed. The planned movement trajectory is, for example, the path of the coordinate values ​​of the welding torch tip over time (elapsed time) from the start of operation. The planned movement trajectory may be given, for example, by the coordinate values ​​that the welding torch passes through at regular intervals. The planned movement trajectory may include the planned movement speed of the welding torch at regular intervals. The coordinate values ​​are based, for example, on the reference point of the robot arm or the reference point of the object to be welded. The coordinate values ​​are based, for example, on the reference point of the robot arm or the reference point of the object to be welded. The coordinate values ​​include, for example, coordinate values ​​in the left-right direction (X direction), front-back direction (Y direction), up-down direction (Z direction), rotation direction around the X direction (A direction), rotation direction around the Y direction (B direction), and rotation direction around the Z direction (C direction). The planned movement trajectory may be given by the coordinate values ​​that the welding torch passes through at regular intervals. In this case, the planned movement trajectory may include the planned movement speed of the welding torch at regular intervals. Welding conditions may be entered by the operator. Welding conditions may also be stored in memory beforehand. Examples of welding conditions include the type of workpiece to be welded, the groove shape of the part to be welded on the workpiece, the welding sequence, the welding method, the distance of the welding torch to the workpiece, the angle of the welding torch to the workpiece, the movement speed, the power output, the wire feed speed, the wire tip position, and the gas supply amount. Examples of workpiece types include butt welds, cross joints, T-joints, square joints, backing joints, and lap joints. The type of workpiece may also include the welding method. Examples of welding methods include butt welds, fillet welds, and shear welds. Examples of welding sequences include symmetrical welds, backward welds, and stone-throwing welds. Examples of welding methods include stringer bead welds and weaving welds. Examples of power output include welding current, arc voltage, laser power output, laser waveform, and spot diameter. Welding conditions may be given according to the type of object to be welded, the material of the base metal constituting the object to be welded, the thickness of the base metal, and the groove dimensions. The welding conditions are stored, for example, as a welding conditions table. The memory unit stores the data of the performed welding as execution data. The execution data may include the movement trajectory of the welding torch (execution trajectory), output, output waveform, shielding gas flow rate, score, comments, and time taken. The execution trajectory is, for example, a record of the coordinate values ​​of the welding torch tip against the time elapsed since the start of operation. The reference point for the coordinate values ​​may be, for example, the reference point of the robot arm or the reference point of the object to be welded. The coordinate values ​​include, for example, coordinate values ​​in the X, Y, Z, A, B, and C directions. The welding energy output, shielding gas flow rate, and wire supply speed may be recorded against the elapsed time. Ratings and comments may be entered by the workers. Ratings may be given, for example, on a 5-point scale.

[0010] The welding system may have an evaluation unit. The evaluation unit may create an evaluation trajectory. For example, the evaluation trajectory can be created based on a 3D model or a planned movement trajectory. For example, the evaluation trajectory is a trajectory obtained by offsetting the distance between the welding torch and the workpiece by a predetermined safety distance. After welding is completed, the evaluation unit may evaluate the welded workpiece. The evaluation unit may perform, for example, a visual inspection or an ultrasonic test. The operation unit moves the robot arm along the evaluation trajectory. Measurement sensors measure the state of the workpiece. The evaluation unit evaluates the measured state of the workpiece. The evaluation unit assigns a score to the welding result. The evaluation unit may also perform the evaluation while welding is in progress.

[0011] The welding system may have a monitoring terminal. The monitoring terminal is connected to the storage unit by, for example, a bus, intranet, internet, or dedicated line. The monitoring terminal is, for example, a portable information terminal. The monitoring terminal displays a 3D model, welding condition table, planned movement trajectory, and execution data for the object being welded during welding. The monitoring terminal also displays a 3D model, welding condition table, planned movement trajectory, and execution data for objects that have been welded in the past.

[0012] The welding system may have a reading unit that reads unique information of the object to be welded. This unique information may be, for example, the object number, the object name, or the manufacturing lot number. The unique information may be stored in, for example, a barcode, an IC tag, or an RF tag. The barcode or tag may be attached to the base material to be welded or to a document. The reading unit may be, for example, a barcode reader or an RFID reader / writer. Based on the information read by the reading unit, the control unit may read the planned movement trajectory or average path from the storage unit. The control unit may operate the welding robot based on the read planned movement trajectory or average path. [Effects of the Invention]

[0013] According to the present invention, it is possible to easily create a planned movement trajectory of the welding torch based on a 3D model without requiring teaching work, and to automatically execute welding work by a welding robot according to the created planned movement trajectory and the shape of the welding target part detected during welding.

Brief Description of Drawings

[0014] [Figure 1] Welding robot of the embodiment [Figure 2] Welding system of the embodiment [Figure 3] Welding condition table of the embodiment [Figure 4] Execution data of the embodiment [Figure 5] Flowchart showing the welding method of the embodiment [Figure 6] Designation of the 3D model and the welding target part of the embodiment

Mode for Carrying Out the Invention

[0015] As shown in FIG. 1, the welding robot 21 of the present embodiment includes a robot arm 23, a welding torch 25, and a measurement sensor 27. The welding object 10 to be welded by the welding robot 21 includes a first base material 11 and a second base material 12. The first base material 11 and the second base material 12 overlap with their side end faces in a mismatched state. By welding the side end face of the first base material 11 with the robot arm 23, the first base material 11 and the second base material 12 are integrated.

[0016] The welding torch 25 and the measurement sensor 27 are supported at the tip of the robot arm 23. The robot arm 23 is an articulated robot. The robot arm 23 moves the welding torch 25. The measurement sensor 27 monitors the front and periphery of the welding target part 15, which is welded by the welding torch 25, among the welding objects 10. The measurement sensor 27 is a camera. The measurement sensor 27 acquires image data including distance information by visible light, infrared light, laser light, etc. The gap 29 is the distance between the welding object 10 and the welding torch 25.

[0017] As shown in Figure 2, the welding system 9 of this embodiment includes a welding robot 21, a control unit 31, a storage unit 41, a trajectory creation unit 51, a welding device 37, and a monitor terminal 49. The control unit 31 includes an operation unit 33 and a correction unit 35. The operation unit 33 numerically controls the robot arm 23. The operation unit 33 controls the welding device 37. The welding device 37 includes a welding power supply, a wire supply device, and a shielding gas supply device. The welding device 37 supplies the welding power supply, wire, and shielding gas to the welding torch 25. The welding device 37 controls the welding current, wire supply speed, and gas flow rate. The memory unit 41 stores the 3D model 42, the welding condition table 43, the planned movement trajectory (program) 47, and the execution data 48. As shown in Figure 6, the 3D model 42 is a 3D model of the object to be welded 10. The 3D model 42 has a first base material 61, a second base material 62, and welding instruction lines 65. The trajectory creation unit 51 creates a planned movement trajectory 47 based on the 3D model 42 and the welding condition table 43. The trajectory creation unit 51 modifies the welding condition table 43 based on the execution data 48. The monitor terminal 49 is connected to the storage unit 41. The monitor terminal 49 can register various types of data in the storage unit 41 and read execution data 48. The correction unit 35 corrects the planned movement trajectory 47 read by the operation unit 33 based on the measurement data of the welding target part 15 measured by the measurement sensor 27.

[0018] As shown in Figure 3, the welding conditions table 43 of this embodiment includes welding conditions corresponding to each of the joint types 44, 45, and 46. The welding conditions include, for example, a gap 29, a speed 71, and an angle 73. The angle 73 is the angle of the torch 25 relative to the part to be welded 15.

[0019] As shown in Figure 4, the execution data 48 records the welding execution status. The execution data 48 includes, for example, the execution date and time 81, the file name of the 3D model 82, the type of joint 83, the material of the base material 11 and base material 12 84, the torch number 85, the score 86, the welding location 87, the comments 88, and the execution trajectory 91. The execution trajectory 91 includes the X coordinate, Y coordinate, Z coordinate, A coordinate, B coordinate, C coordinate, welding current 95, and wire feed speed 97 for the elapsed time 93 from the start of welding. The comments 88 are text data. The score 86 and comments 88 may be entered by the operator.

[0020] As shown in Figure 5, in step S1, the operator fixes the workpiece 10 having a first base material 11 and a second base material 12 to a predetermined position on the base plate. The workpiece 10 is fixed within the operating area of ​​the welding robot 21. In step S2, the operator designates the part to be welded 15 on the 3D model 42. In step S3, the trajectory creation unit 51 creates a planned movement trajectory 47. In step S4, the welding robot 21 moves along the planned movement trajectory 47. In step S5, the measurement sensor 27 measures the part to be welded 15. In step S6, the correction unit 35 corrects the planned movement trajectory 47. In step S7, the welding robot 21 welds the part to be welded 15. Specifically, the welding equipment 37 supplies welding current, shielding gas (not shown), and wire (not shown) to the welding torch 25. An arc is generated from the welding torch 25, the wire is supplied to the molten pool, and welding is performed. In step S8, the execution data 48 is saved. In step S9, it is determined whether the welding torch 25 has reached the welding end 69. If YES, the process ends. If NO, the process returns to step S4. Steps S4 to S8 are executed simultaneously. In other words, the robot arm 23 proceeds with welding while correcting the planned movement trajectory 47, and the operation unit 33 sequentially records the welding status as execution data 48.

[0021] Refer to Figure 6 to explain step S2. The operator indicates the edge line 65 to be welded on the 3D model 42. For example, when the operator clicks on a point (indication point 65a) on the edge line 65, the trajectory creation unit 51 determines that the edge line 65 is the welding instruction unit 65. The operator sets one of the ends of the part to be welded 15 as the welding start point 67. The trajectory creation unit 51 sets the other end as the welding end point 69.

[0022] The correction unit 35 corrects the positional and morphological deviations between the welding object 10 in real space and the 3D model 42 in virtual space. The corrected planned movement trajectory 47, welding current, wire supply speed, etc., are transmitted from the control unit 31 to the storage unit 41 and stored as execution data 48. The stored execution data 48 is referenced to modify the welding condition table 43. This improves the welding quality.

[0023] The present invention is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention. All technical matters included in the technical concept described in the claims are covered by the present invention. The embodiments described above are preferred examples, but those skilled in the art can realize various alternatives, modifications, variations, or improvements from the contents disclosed herein, and these are included in the technical scope described in the appended claims. [Explanation of Symbols]

[0024] 9 Welding Systems 10. Objects to be welded 11 First base material 12 Second base material 15. Welding target area 21 Welding robots 23 Robot Arm 25 Welding Torch 27 Measurement and Recovery 31 Control Unit 33. Driver's Unit 35 Correction section 41 Storage section 42 3D models 47 Planned movement trajectory 51 Track Creation Section 61 1st base material 62 2nd base material 65 Ridge

Claims

1. It is a welding robot, A robotic arm and A welding torch positioned at the tip of the robot arm, A measuring sensor is positioned at the tip of the robot arm to measure the position and shape of the part of the object to be welded, A welding robot having, A trajectory creation unit creates a planned trajectory for the welding torch based on a 3D model of the part to be welded, A control unit that operates the welding robot to weld the part to be welded, An operating unit that operates the welding robot along the aforementioned planned movement trajectory, A correction unit corrects the planned movement trajectory based on the position and shape of the part to be welded measured by the measurement sensor, A control unit having, A welding system having the following features.

2. It is a memory unit, The aforementioned 3D model and, The planned movement trajectory associated with the 3D model, The execution trajectory of the welding torch, which is associated with the 3D model and corrected by the correction unit, It further has a memory unit for storing the The welding system according to claim 1.

3. A welding energy source that supplies welding energy to the welding torch, The system further includes an output adjustment unit that adjusts the output of the welding energy based on the position and shape of the part to be welded measured by the measurement sensor, The memory unit stores the output actually applied to the welding torch in relation to the 3D model. The welding system according to claim 1 or 2.

4. The aforementioned storage unit is The type of part to be welded, Welding conditions corresponding to the above types, The welding start point and welding end point in the 3D model, Store it, The trajectory creation unit creates the planned movement trajectory based on the 3D model, the welding start point, the welding end point, and the type. The welding system according to claim 2 or 3.

5. The aforementioned storage unit is The date and time the welding was performed, The execution trajectory related to the execution date and time, The score related to the execution date and time, Store it, The trajectory creation unit creates the planned movement trajectory based on the executed trajectory and the score. A welding system according to any one of claims 2 to 4.

6. A welding method using a welding robot, On the 3D model of the object to be welded, specify the welding start point and welding end point. The trajectory creation unit creates the planned trajectory of the welding torch based on the type and shape of the object to be welded. The welding robot moves the welding torch based on the planned movement trajectory. As the welding torch moves, the measuring sensor positioned adjacent to the welding torch continuously measures the shape of the part of the object to be welded and the distance between the part to be welded and the welding torch. Based on the measured shape, distance, and type, the welding robot supplies energy to the welding torch while correcting the position of the welding torch, and the welding torch welds the part to be welded. The system records the actual trajectory of the welding torch as it moves. Welding method.

7. Furthermore, The energy output from the welding torch is recorded in relation to the elapsed time from the start of welding. The welding method according to claim 6.

8. Furthermore, Record the score of the welded part after the welding is completed. The trajectory creation unit creates the planned movement trajectory based on the score and the executed trajectory. The welding method according to claim 6 or 7.

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