Computer, robot system equipped with it, positional relationship acquisition program, and positional relationship acquisition method

Abstract

The system allows information regarding the relative positions of the robot and the workpiece during welding to be used after the welding process is complete. [Solution] The computer 4 is provided with a storage unit 4a that stores three-dimensional robot shape data showing the shape of the robot 1, three-dimensional workpiece shape data showing the shape of the workpiece W to be welded, reference position information showing the positional relationship between the robot 1 and the workpiece W at predetermined timings, and robot position information showing the position of the robot 1 at multiple timings during welding of the workpiece W, and stores the workpiece shape data and reference position information for multiple types of workpiece W, and a calculation unit 4b that generates welding position information for multiple types of workpiece W according to the positional relationship between the robot 1 and the workpiece W at multiple timings based on the robot shape data, workpiece shape data, reference position information and robot position information stored in the storage unit 4a.

Description

Technical Field

[0001] The present disclosure relates to a technique for generating in-welding position information according to the positional relationship between a robot and a workpiece during welding.

Background Art

[0002] The robot device disclosed in Patent Document 1 includes a storage unit that stores the setting information, current position, welding conditions, input / output information, etc. of the robot as operation information indicating the operation status of the robot, and a server that identifies the operation information before and after the timing when a trigger condition such as an error occurs.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, there is a desire to make the information according to the positional relationship between the robot and the workpiece during welding available for considering a better welding method after welding. In Patent Document 1, nothing is disclosed about acquiring information regarding the positional relationship between the robot and the workpiece.

[0005] <关于获取机器人与工件的位置关系的信息,专利文献1中未作任何披露。 The present disclosure has been made in view of this point, and the object thereof is to make the information according to the positional relationship between the robot and the workpiece during welding available after welding. <关于获取机器人与工件的位置关系的信息,专利文献1中未作任何披露。

Means for Solving the Problems

[0007] As a result, the calculation unit generates welding position information according to the positional relationship between the robot and the workpiece, and this welding position information can be used after welding is complete to consider better welding methods. [Effects of the Invention]

[0008] According to this disclosure, welding position information, which corresponds to the positional relationship between the robot and the workpiece, can be used after the welding is completed. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram showing the configuration of a robot system according to an embodiment of this disclosure. [Figure 2] Figure 2 is a flowchart showing the operation of the robot system. [Figure 3] Figure 3 shows a table displayed on the display screen of a display device. [Figure 4] Figure 4 shows the display screen that appears on the display device when the details button for the table shown in Figure 3 is clicked. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below with reference to the drawings. The following description of preferred embodiments is essentially illustrative and is not intended to limit the present invention, its applications, or its uses in any way.

[0011] Figure 1 shows a robot system 10 according to Embodiment 1 of the present disclosure. This robot system 10 is used to perform laser processing such as cutting and welding of a workpiece W. The robot system 10 comprises a robot 1, a robot controller 2, a welding control device 3, a computer 4, a display device 5, and a mouse 6 as an input device. The display device 5 is, for example, a liquid crystal display.

[0012] Robot 1 is composed of a multi-axis, articulated robot with multiple servo motors 1a. A welding torch 1c and a wire feeder 1d are attached to the tip of the robot arm 1b. The number of joint axes and the configuration of Robot 1, such as whether it is a horizontal or vertical articulated robot, can be appropriately selected according to the application.

[0013] The robot controller 2 transmits a welding current command value to the welding control device 3. The robot controller 2 also receives measured values ​​of the welding current and welding voltage from the welding control device 3. The robot controller 2 then detects welding defects based on the welding current command value and the measured welding current. The robot controller 2 detects welding defects when the difference between the welding current command value and the measured welding current deviates from a predetermined current range. The robot controller 2 also detects welding defects when the difference between the welding voltage command value and the measured welding voltage deviates from a predetermined voltage range. Furthermore, the robot controller 2 detects welding defects when the number of short circuits during welding deviates from a predetermined range.

[0014] Furthermore, the robot controller 2 stores robot position information indicating the position of robot 1 at multiple timings during welding, the timing of welding defects, and the location of the welding defects on the workpiece W, and transmits this information to the computer 4. The robot position information is data that shows the position of the robot during welding in chronological order.

[0015] Furthermore, the robot controller 2 stores time-series data of the welding current (measured value of welding current), welding current command value, welding voltage (measured value of welding voltage), and welding voltage command value during welding, and transmits this data to the computer 4. This time-series data of the welding current, welding current command value, welding voltage, and welding voltage command value becomes data showing the waveforms of the welding current, welding current command value, welding voltage, and welding voltage command value.

[0016] The welding control device 3 supplies a welding current between the welding wire and the workpiece W according to the welding current command value transmitted by the robot controller 2. The welding control device 3 controls the welding current to approach the welding current command value. The welding control device 3 measures the actual welding current flowing and transmits the measured value to the robot controller 2.

[0017] Computer 4 is a personal computer (PC). Computer 4 comprises a storage unit 4a and an arithmetic unit 4b.

[0018] The storage unit 4a stores three-dimensional robot shape data showing the shape of robot 1, three-dimensional workpiece shape data showing the shape of workpiece W, and reference position information showing the positional relationship between robot 1 and workpiece W at the start of welding. The storage unit 4a stores the workpiece shape data and reference position information for multiple types of workpiece W. The storage unit 4a further stores the robot position information. The robot shape data and workpiece shape data are 3D (three-dimensional) computer graphics (CG) models. The robot shape data shows the shape of robot 1. The workpiece shape data shows the shape of workpiece W. The storage unit 4a also stores the timing of the occurrence of welding defects and the location of the welding defects on workpiece W. Furthermore, the storage unit 4a stores the type of welding defect that occurred on workpiece W and the type of robot 1 that caused the welding defect. The storage unit 4a stores time-series data of welding current, welding current command value, welding voltage, and welding voltage command value during welding.

[0019] The calculation unit 4b receives the robot position information, the occurrence timing of welding defects, and the occurrence position of welding defects in the workpiece W from the robot controller 2, and stores them in the storage unit 4a. The calculation unit 4b further receives the time-series data of the welding current, the welding current command value, the welding voltage, and the welding voltage command value during welding from the robot controller 2, and stores them in the storage unit 4a.

[0020] Based on the robot shape data, the workpiece shape data, the reference position information, and the robot position information stored in the storage unit 4a, the calculation unit 4b generates welding position information corresponding to the positional relationship between the robot 1 and the workpiece W at a plurality of timings for a plurality of types of workpieces W. The welding position information at a plurality of timings is data indicating the positional relationship between the robot 1 and the workpiece W for each predetermined timing in time series. Specifically, the welding position information is time-series video data of the robot 1 and the workpiece W in which the positional relationship at each timing is reflected.

[0021] The calculation unit 4b causes the display device 5 to display the type of the workpiece W, the type of welding defect, the type of the robot 1, and the position of the welding defect in an order corresponding to the number of welding defects at a plurality of positions of the workpiece W. Specifically, the calculation unit 4b causes the display device 5 to display a table as shown in FIG. 3. The table in FIG. 3 shows, in order from the left, the type of the workpiece, the type of welding defect, the type of the robot, and the position of the welding defect, in order from the position with the largest number of welding defects. The first row of this table indicates that a welding defect in which the difference between the welding current command value and the welding current deviates from a predetermined current range has occurred at bead No. 1 when welding is performed on the workpiece A by the robot R1. Also, the second row of this table indicates that a welding defect in which the difference between the voltage command value and the welding voltage deviates from a predetermined voltage range has occurred at bead No. 5 when welding is performed on the workpiece B by the robot R1. Further, the third row of this table indicates that a welding defect in which the number of short circuits during welding deviates from a predetermined range has occurred at bead No. 2 when welding is performed on the workpiece C by the robot R2. Also, this table shows that among bead No. 1 of the workpiece A, bead No. 5 of the workpiece B, and bead No. 2 of the workpiece C, the most welding defects occur at bead No. 1 of the workpiece A, the second most welding defects occur at bead No. 5 of the workpiece B, and the third most welding defects occur at bead No. 2 of the workpiece C. Also, at the right end of each row of this table, a button described as "Details" is displayed.

[0022] In a state where the table shown in FIG. 3 is displayed on the display device 5, when the user moves the cursor to any of the buttons displayed at the right end of the table and clicks the mouse 6, the calculation unit 4b reads the time-series data from the storage unit 4a and causes the display device 5 to display an image as shown in FIG. 4 based on the time-series data.

[0023] Figure 4 shows waveforms (timing charts) of the welding current, welding current command value, welding voltage, and welding voltage command value, as well as the robot 1 and workpiece W during welding. The positional relationship between robot 1 and workpiece W in Figure 4 corresponds to the positional relationship between robot 1 and workpiece W at the timing indicated by the thick line WL in the waveform. The user can move the thick line WL along the time axis by operating the mouse 6. As the user gradually moves the thick line WL from left to right, the movement of robot 1 during welding is reproduced on the screen. In this way, the calculation unit 4b displays an image corresponding to the time-series data on the display device 5, and then displays an image of robot 1 and workpiece W on the display device 5 that reflects the positional relationship at the timing specified by the input to the mouse 6.

[0024] Next, the operation of the robot system 10 will be explained with reference to the flowchart in Figure 2. The operation by the computer 4 is realized when the calculation unit 4b executes the position relationship generation program stored in the memory unit 4a.

[0025] First, in S101, computer 4 links the robot shape data, workpiece shape data, and reference position information mentioned above by executing software. Furthermore, when computer 4 begins communication with robot 1, it identifies the type of robot 1 it is communicating with, and when robot 1 begins production, it determines the type of workpiece W that robot 1 will be welding.

[0026] Next, in S102, the robot controller 2 detects a welding defect. As described above, the detection of the welding defect is performed based on the welding current command value, the measured welding current, the welding voltage command value, and the measured welding voltage.

[0027] Furthermore, in S102, the robot controller 2 saves the robot position information described above, the timing of the detected welding defect, and the location of the detected welding defect on the workpiece W, and transmits them to the computer 4. The robot position information is created by the robot controller 2 executing a predetermined program to cause the robot 1 to perform welding operations. Specifically, the robot controller 2 acquires and stores the position of the robot 1 during welding at predetermined intervals (for example, 100 ms). Since the computer 4 can grasp the start and end timings of welding, it acquires the time-series data of the robot 1's position stored from the start to the end of welding as robot position information.

[0028] Alternatively, the robot controller 2 may transmit information indicating the position of the robot 1 to the computer 4 at predetermined intervals from the start to the end of welding, and the computer 4 may acquire the robot position information by receiving the transmitted information.

[0029] Next, in S103, the robot controller 2 stores time-series data of welding current, current command value, welding voltage, and voltage command value during welding and transmits it to the computer 4.

[0030] Next, in S104, the calculation unit 4b of the computer 4 acquires the information linked in S101, the information transmitted in S102, and the information transmitted in S103, and stores them in a single common database record in the storage unit 4a. In other words, the calculation unit 4b acquires robot shape data, workpiece shape data, reference position information, robot position information, timing of welding defect occurrence, location of welding defect on workpiece W, and time-series data of welding current, current command value, welding voltage, and voltage command value during welding, and stores them in a single database record in the storage unit 4a. This makes it possible to later refer to and analyze the time-series data of the location of welding defect occurrence, welding current, current command value, welding voltage, and voltage command value on workpiece W.

[0031] Note that the storage of the information transmitted in S102 by the arithmetic unit 4b in the database of the storage unit 4a may be performed before the execution of S103.

[0032] Next, in S105, the calculation unit 4b displays the type of workpiece W, the type of welding defect, the type of robot 1, and the location of the welding defect on the display device 5 in an order corresponding to the number of welding defects at multiple locations on the workpiece W. Specifically, the calculation unit 4b displays a table on the display device 5 as shown in Figure 3. By referring to this table, the user can understand which workpiece W and at which location the most welding defects occur. When the user moves the cursor to one of the buttons displayed on the right end of the table and clicks the mouse 6, the calculation unit 4b reads time-series data from the storage unit 4a and displays an image on the display device 5 as shown in Figure 4, based on the time-series data. This allows the user to understand the trends in the waveforms of the welding current and welding voltage when welding defects occur. In addition, the calculation unit 4b generates time-series video data (welding position information) of robot 1 and workpiece W for multiple types of workpiece W based on the robot shape data, workpiece shape data, reference position information, and robot position information stored in the storage unit 4a. The calculation unit 4b then displays an image based on the generated video data on the display device 5. The positional relationship between the robot 1 and the workpiece W in the image of Figure 4 corresponds to the positional relationship between the robot 1 and the workpiece W at the timing corresponding to the thick line WL of the waveform. The user can easily recognize the positional relationship between the robot 1 and the workpiece W at each timing during welding when a welding defect occurs by visually inspecting the images of the robot 1 and the workpiece W.

[0033] In this embodiment, the calculation unit 4b generates time-series video data (welding position information) showing the positional relationship between the robot 1 and the workpiece W. Therefore, this video data can be used after welding is completed to investigate methods for performing better welding.

[0034] Furthermore, the calculation unit 4b generates video data as information indicating the positional relationship between the robot 1 and the workpiece W, so that the video data can be used to display a video showing the positional relationship on the display device 5.

[0035] Furthermore, in S105, the calculation unit 4b displays the location of the welding defect on the display device 5, so the user can understand which workpiece W and where the welding defect occurred by referring to the display on the display device 5.

[0036] Furthermore, in S105, the calculation unit 4b displays the type of welding defect on the display device 5, so the user can understand what type of welding defect has occurred by referring to the display on the display device 5.

[0037] Furthermore, in S105, the calculation unit 4b displays the type of robot 1 on the display device 5, so the user can understand which robot 1 caused the welding defect by referring to the display on the display device 5.

[0038] Furthermore, in S105, the calculation unit 4b can display an image based on time-series data on the display device 5, allowing the user to understand whether there is a trend in the transitions of the welding current and welding voltage (parameters) during welding.

[0039] Furthermore, in S105, the calculation unit 4b displays an image based on time-series data on the display device 5, and can display an image of the robot 1 and workpiece W on the display device 5 that reflects the positional relationship between the robot 1 and workpiece W at a timing specified by input to the mouse (input device) 6. Therefore, the user can easily recognize the positional relationship between the robot 1 and workpiece W at each timing during welding by visually inspecting the images of the robot 1 and workpiece W.

[0040] In the above embodiment, the reference position information indicates the positional relationship between the robot 1 and the workpiece W at the welding start timing, but it may also indicate the positional relationship at other predetermined reference timings.

[0041] Furthermore, in the above embodiment, the time-series data acquired by the robot controller 2 and stored in the storage unit 4a of the computer 4 was the time-series data of the welding current and welding voltage during welding. However, this time-series data may also be the time-series data of the drive current of the wire feeder during welding. In other words, this time-series data only needs to be the time-series data of at least one parameter among the welding current, welding voltage, and drive current of the wire feeder.

[0042] Furthermore, in the above embodiment, the calculation unit 4b displayed the type of workpiece W, the type of welding defect, the type of robot 1, and the location of the welding defect on the display device 5 in an order corresponding to the number of welding defects. However, it is also possible to sort and display the information using the type of welding defect, the location of the welding defect, and the type of robot 1 as keys. [Industrial applicability]

[0043] The computer, robot system equipped therewith, position relationship acquisition program, and position relationship acquisition method of this disclosure are useful as technologies for generating welding position information corresponding to the position relationship between the robot and the workpiece during welding, as welding position information corresponding to the position relationship between the robot and the workpiece can be used after welding is completed. [Explanation of Symbols]

[0044] 1 Robot 1d Wire feeder 2 Robot Controller 4 Computers 4a Storage section 4b Calculation Unit 5 Display device 6. Mouse (input device) 10 Robot Systems Double job

Claims

1. A storage unit that stores three-dimensional robot shape data showing the shape of the robot, three-dimensional workpiece shape data for multiple types of workpieces showing the shape of the workpiece, reference position information for the multiple types of workpieces showing the positional relationship between the robot and the workpiece at predetermined timings, and robot position information showing the position of the robot at multiple timings during welding. A computer comprising a calculation unit that generates welding position information for multiple types of workpieces, corresponding to the positional relationship between the robot and the workpiece at multiple timings, based on the robot shape data, workpiece shape data, reference position information, and robot position information stored in the storage unit.

2. In the computer according to claim 1, The computer is characterized in that the welding position information is time-series video data of the robot and the workpiece, reflecting the positional relationship at each timing.

3. In the computer according to claim 1, The memory unit further stores the locations of welding defects in the multiple types of workpieces, The computer is characterized in that the calculation unit causes the location of the welding defect to be displayed on a display device.

4. In the computer described in claim 3, The memory unit further stores the types of welding defects in the workpiece. The computer is characterized in that the calculation unit further displays the type of welding defect on the display device.

5. In the computer described in claim 3, The memory unit further stores the type of robot, The computer is characterized in that the calculation unit further displays the type of robot on the display device.

6. In the computer according to claim 1, The storage unit further stores time-series data of at least one parameter among the welding current, welding voltage, and wire feeder drive current during welding. The computer is characterized in that the calculation unit causes an image based on the time-series data to be displayed on a display device.

7. In the computer according to claim 6, The computer is characterized in that, while displaying an image based on the time-series data on the display device, it displays images of the robot and the workpiece, which reflect the positional relationship at a timing specified by input to the input device, on the display device based on the welding position information.

8. The computer according to claim 1, A display device that outputs an image based on the welding position information, The aforementioned robot, A robot system comprising a robot controller that transmits the robot position information to the computer.

9. A position relationship acquisition program that generates welding position information for multiple types of workpieces, corresponding to the position relationship between the robot and the workpiece at multiple timings, based on three-dimensional robot shape data showing the shape of the robot, three-dimensional workpiece shape data for multiple types of workpieces showing the shape of the workpiece, reference position information for the multiple types of workpieces showing the positional relationship between the robot and the workpiece at predetermined timings, and robot position information showing the position of the robot at multiple timings during welding.

10. A method for acquiring positional relationships, which generates welding position information for multiple types of workpieces that corresponds to the positional relationship between the robot and the workpiece at multiple timings, based on three-dimensional robot shape data showing the shape of the robot, three-dimensional workpiece shape data for multiple types of workpieces showing the shape of the workpiece, reference position information for the multiple types of workpieces showing the positional relationship between the robot and the workpiece at predetermined timings, and robot position information showing the position of the robot at multiple timings during welding.

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