JP2019063840A - Welding robot system and method of specifying welding abnormality position - Google Patents

Abstract

To provide a welding robot system capable of easily specifying a position of welding abnormality actually generated on a welded article.SOLUTION: The welding robot system is equipped with a welding robot 100 and a robot control device 1. The robot control device 1 is equipped with an obtaining portion 12 which obtains a waveform of at lease one of a welding voltage and a welding current of welding executed by the welding robot 100; and a welding waveform analyzing device 11 which analyzes a waveform in a predetermined welding section of the waveforms obtained by the obtaining portion 12. The welding robot 100 is equipped with a marking mechanism 120 which applies marking to the work 200 during the welding by the welding robot 100, when it is determined by the welding waveform analyzing device 11 that the waveform in the predetermined welding section satisfies conditions of welding abnormality.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a welding robot system and a method of identifying a welding abnormality position.

  Conventionally, the welding voltage or welding current of welding performed by a welding robot is measured, and the waveform of the welding voltage or welding current (hereinafter also referred to as welding waveform) is graphically displayed to monitor the state of welding. There is.

  For example, in Patent Document 1, welding is performed by operating a manipulator based on an operation program taught in advance, and welding related to a welding current command value during welding, a welding current output value, a welding voltage command value, and a welding voltage output value An arc welding robot is described which comprises display means for graphically displaying the waveforms.

Unexamined-Japanese-Patent No. 2006-26640 Unexamined-Japanese-Patent No. 11-58007 gazette

  By the way, when it determines with welding defect based on a welding waveform, it is necessary to specify in which part of the work (it is hereafter called a workpiece to be welded) welding actually occurred. In Patent Document 1, although it is possible to confirm the teaching position based on the graphically displayed welding waveform, based on the teaching position, it is specified in which part of the workpiece the welding failure actually occurred. There was a problem that it was difficult.

  In order to solve such a problem, in Patent Document 2, the operation trajectory of the welding robot is displayed on the display together with the waveforms of the welding voltage and the welding current, and the operation trajectory of the welding robot and the waveform are made to correspond. Techniques to confirm have been proposed. According to Patent Document 2, when a welding defect is detected based on the welding waveform, it is possible to confirm on the display the movement trajectory of the welding robot corresponding to the portion where the welding defect is detected, It seems that 1 has solved the problem to some extent.

  However, even if the technology described in Patent Document 2 is adopted, it can be understood only at which operation point of the welding robot a defect has occurred, and which part of the workpiece actually corresponds to the operation point It was hard to understand.

  Then, an object of the present invention is to provide a welding robot system and a method of specifying a welding abnormality position which can easily specify a position of a welding abnormality actually generated in a workpiece.

  A welding robot system according to an aspect of the present invention is a welding robot system including a welding robot and a robot control unit for controlling the welding robot, wherein the robot control unit is a welding voltage and a welding of welding performed by the welding robot. The welding robot includes an acquisition unit for acquiring at least one waveform of the current, and a welding waveform analysis unit for analyzing a waveform of a predetermined welding section of the waveforms acquired by the acquisition unit. A marking mechanism is provided that applies markings to the workpiece during welding by the welding robot when it is determined by the welding waveform analysis unit that the welding abnormality condition is satisfied.

  According to this aspect, when it is determined by the analysis unit that at least one of the welding voltage and the welding current waveform of the welding satisfies the condition of welding abnormality, the marking mechanism welds the marking on the object to be welded. Since the inspection is performed after the welding, the position of the welding abnormality actually produced on the object to be welded can be easily identified.

  In the above aspect, the robot control unit includes the storage unit that stores the waveform acquired by the acquisition unit, and the welding abnormality condition is determined by storing the measured value of the welding current acquired by the acquisition unit in the welding section in the storage unit It may be less than a threshold determined based on the selected waveform.

  According to this aspect, marking is applied to the object to be welded by the marking mechanism on the condition that the measured value of the welding current is less than a predetermined threshold value, and therefore, a point at which an abnormality is detected in the waveform of the welding current Can be easily identified by checking the markings after welding.

  In the above aspect, the marking mechanism includes a marking device attached to the arm of the welding robot, and a marking control unit that controls the marking device based on a command output from the welding waveform analysis unit, and the marking control unit The marking device may be controlled to apply a liquid capable of identifying a portion of the welded portion that satisfies the condition of the welding abnormality to the workpiece.

  According to this aspect, since the marking apparatus applies the distinguishable liquid to the object to be welded, the object to be welded is actually confirmed by confirming the liquid applied to the object to be welded after completion of welding by the welding robot. It is possible to easily identify the location of the welding abnormality that has occurred.

  In the above aspect, the marking control unit may control the marking device to apply different types of liquids based on the command output from the welding waveform analysis unit.

  According to this aspect, since different types of liquids are applied to the object to be welded by the marking device, for example, in the case where a plurality of commands output from the welding waveform analysis unit are set, different types of It is possible to apply the liquid to the workpiece by properly using the liquid.

  According to another aspect of the present invention, there is provided a method of identifying a welding abnormality position comprising: performing welding by a welding robot according to a work program including welding application conditions; and welding voltage and welding current of welding performed by the welding robot. The step of acquiring at least one of the waveforms by the acquisition unit, the step of analyzing the waveform acquired by the acquisition unit by the welding waveform analysis unit, and the welding acquired when the waveform acquired by the acquisition unit satisfies the condition of welding abnormality Applying a marking to the workpiece by the marking device during welding by the welding robot, as determined by the waveform analysis unit.

  According to this aspect, when the analysis unit determines a waveform that satisfies the condition of the welding abnormality, marking is performed on the object to be welded during welding by the marking mechanism. In addition, it is possible to easily identify the welding abnormality point that has occurred in the object to be welded.

  According to the present invention, it is possible to provide a welding robot system capable of easily identifying the position of a welding abnormality actually produced on a workpiece and a method of identifying a welding abnormality position.

It is a figure showing an outline of a welding robot system concerning this embodiment. It is a functional block diagram of the welding robot system shown in FIG. It is a flowchart which shows an example of the control processing performed by the welding robot system shown in FIG. It is a flowchart which shows an example of the marking process shown in FIG. It is a flowchart which shows an example of the screen displayed on the display part shown in FIG.

  Embodiments of the present invention will be described with reference to the accompanying drawings. In addition, what attached the same code | symbol in each figure has the same or same structure.

  FIG. 1 is a view showing an outline of a welding robot system according to the present embodiment. In the example shown in the figure, the welding robot system includes a robot control device 1, a welding power source 20, a current / voltage measuring device 30 and a welding robot 100, and the robot control device 1 includes a welding waveform analysis device 11. The welding robot system may include other configurations than these, or may not necessarily include all the configurations. In addition, the welding waveform analysis device 11 may be a device integrated with the robot control device 1 or may be a separate device.

  The robot control device 1 reads a program in which the operation of the welding robot 100 is described, and controls the welding robot 100 and the welding power source 20. The welding robot 30 is a device that performs arc welding. Welding robot 100 is an industrial robot having an articulated arm, and is a robot equipped with welding torch 102 as an end effector. The welding torch 102 includes a feeding mechanism for feeding the welding wire 110. The arc welding is performed by feeding the welding wire 110 by a feeding mechanism provided to the welding torch 102 and generating an arc between the tip of the welding wire 110 and the workpiece 200. A marking mechanism 120 is provided on the side of the welding torch 102. In the present embodiment, the marking mechanism 120 is attached to the welding torch 102. However, the present invention is not limited to this configuration, and the marking mechanism 120 may be included as a configuration (integral or separate configuration) of the welding robot 100. The details of the configuration of the marking mechanism 120 will be described later.

  The welding power source 20 transmits power to the welding torch 102 via a cable. Welding robot 100 moves welding torch 102 in response to voltage and current supplied from welding power source 20, and performs arc welding of workpiece 200. Here, the workpiece 200 is placed on the welding base 300, one of the electrodes of the welding power source 20 is connected to the welding wire 110, and the other is connected to the welding base 300.

  The current / voltage measurement device 30 measures at least one of the voltage and the current between the welding wire 110 and the welding base 300. The current / voltage measurement device 30 may transmit the measured values to the acquisition unit 12 (see FIG. 2) of the robot control device 1 sequentially.

  FIG. 2 is a functional block diagram of the robot control device 1 shown in FIG. The robot control device 1 includes an analysis unit 2, an execution unit 3, a welding control unit 4, a servo control unit 5, a program storage unit DB 1, a welding condition storage unit DB 2, a current / voltage storage unit DB 3, a welding waveform analysis device 11, an acquisition unit 12 and the display unit 13.

  The program storage unit DB1 is a storage unit that stores a program in which the operation of the welding robot 100 is described, and may be configured by a semiconductor memory or a hard disk drive. Welding robot 100 executes welding based on a program stored in program storage unit DB1. The analysis unit 2 analyzes the program stored in the program storage unit DB1, and at least, from the program, a control command of the servomotor 101 that constitutes a joint of the welding robot 100 and the current and voltage supplied by the welding power supply 20 Read current and voltage control commands to control.

  The execution unit 3 coordinates and controls the welding power supply 20 and the servomotor 101 based on the control command read by the analysis unit 2. Welding control unit 4 transmits command values of current and voltage to welding power supply 20. The servo control unit 5 transmits command values such as angle, angular velocity, and angular acceleration to each servo motor 101.

  The welding condition storage unit DB2 refers to the program stored in the program storage unit DB1, reads the welding conditions of the welding performed by the welding robot 100, and stores them in association with at least the teaching point of the welding robot 100. Here, the welding conditions may be described in a file referenced by a program. For example, the program may include a welding start instruction that causes welding robot 100 to start welding, and the welding start instruction may include a reference to a file in which welding conditions are described. Here, the file in which the welding conditions are described is a file different from the program, but may be stored in the program storage unit DB1. In such a case, welding conditions described in the file referred to in the welding start command are stored in the welding condition storage unit DB2. Also, the welding conditions may be described in a program. For example, the header of the welding start command that causes welding robot 100 to start welding may include a description of the welding conditions. In such a case, welding conditions described in the header of the welding start command are stored in the welding condition storage unit DB2.

  The acquisition unit 12 acquires a waveform of at least one of a welding voltage and a welding current of welding performed by the welding robot 100. Here, the welding voltage and the welding current when the welding robot 100 performs welding are the voltage and the current measured by the current and voltage measuring device 30, and the acquiring unit 12 measures the voltage and the current by the current and voltage measuring device 30. At least one of the voltage and the current is acquired.

  The current / voltage storage unit DB3 stores the waveform of at least one of the welding voltage and the welding current acquired by the acquiring unit 12.

  The welding waveform analysis device 11 receives program data including the waveform acquired by the acquisition unit 12 and the welding conditions stored in the welding condition storage unit DB2, and the welding abnormality set in advance by an input / output terminal (not shown) Analyze the waveform that satisfies the condition. In the present embodiment, at the time of analysis of the waveform satisfying the welding abnormality condition by the welding waveform analysis device 11, the welding waveform analysis device 11 determines a predetermined welding section during the welding period by the welding robot 100 (hereinafter also referred to as analysis segment). (See below). The analysis section may be set, for example, of a section being welded by the welding robot 100 based on a waveform stored in advance, a welding condition, or the like after a predetermined time from the start of welding and a predetermined time before the end of welding. The analysis section in the present embodiment is indicated by a symbol S in FIG. 5 (a section from time t2 to time t5 shown in FIG. 5). The “predetermined welding section” in the present invention is not limited to the section from time t2 to time t5 shown in FIG. 5, and the portion of the welding abnormality in the portion welded by welding robot 100 is subjected to welding waveform analysis If it can be determined by the device 11, it is arbitrarily set.

  The welding waveform analyzer 11 outputs a marking command (details will be described later) for marking the workpiece 200 during welding by the welding robot 100 to the marking mechanism 120 (see FIG. 1) and marking information including the marking command. Are output to the display unit 13.

  The display unit 13 displays the waveform stored in the current / voltage storage unit DB3, the welding conditions stored in the welding condition storage unit DB2, and the information output from the welding waveform analysis apparatus 11 (for example, welding start time, welding end time, Display analysis segments, analysis conditions, analysis results, marking information, etc.). The display unit 13 may be configured of, for example, a liquid crystal display device provided in a teach pendant. The contents displayed by the display unit 13 will be described later with reference to FIG.

  Returning to FIG. 1, the marking mechanism 120 includes a marking device 121 having a function of applying the marking M to the workpiece 200, and a marking control unit 122 that controls driving of the marking device 121. When the marking control unit 122 of the marking mechanism 120 receives a command (including a command for analysis information such as welding start time, welding conditions, analysis conditions or analysis result, in addition to the marking command) output from the welding waveform analysis device 11, Based on the marking instruction, the marking control unit 122 controls the driving of the marking device 121 (for example, the ejection amount of the marking, the ejection coordinates, the ejection time), and the marking M is applied to the workpiece 200.

  The marking device 121 shown in FIG. 1 is attached to the ink tank 121a in which the visible liquid is stored inside and at the tip of the ink tank 121a, and works the liquid in the ink tank 121a by opening and closing an open / close valve (not shown). And a nozzle 121 b for injecting the light into the nozzle 200. For example, a pneumatic device (not shown) for applying pressure to discharge the liquid in the ink tank 121a is connected to the ink tank 121a, and the liquid to which the pressure is applied by the pneumatic device is discharged from the nozzle 121b. . When the marking control unit 122 receives the marking command from the welding waveform analyzing device 11, the liquid is discharged from the nozzle 121b to a specific part of the workpiece 200 based on the marking command. The application amount of the liquid applied from the nozzle 121b to the workpiece 200 is set based on the marking command output from the welding waveform analyzer 11, and for example, the measured value of the welding condition and welding current, the shape and size of the workpiece 200 The application amount of the liquid is changed according to the length and the like.

  The marking device 121 is not limited to the configuration shown in the drawing, and any other configuration may be used as long as the device has a function of providing a marking capable of identifying a specific part of the workpiece 200. It is.

  Subsequently, control processing executed by the above-described robot control device 1 will be described. FIG. 3 is a flow chart showing an example of control processing executed by the robot control device 1, and FIG. 4 is a flow chart showing an example of the marking processing shown in FIG. FIG. 5 is a view showing a screen DP1 displayed on the display unit 13. As shown in FIG. The screen DP1 is an example in which the waveform of the welding current acquired by the acquisition unit 12 and the analysis conditions set by the welding waveform analyzer 11 are displayed. In the example shown in FIG. 5, the vertical axis indicates the welding current, and the horizontal axis indicates the time, and the welding current changes as time passes. Time t1 shown in FIG. 5 indicates the time when welding by welding robot 100 is started. Time t2 indicates the analysis start time set by the welding waveform analyzer 11. A period from time t3 to time t4 indicates a period that satisfies analysis conditions (described later) set by the welding waveform analyzer 11. Time t5 indicates the analysis end time set by the welding waveform analyzer 11. Time t6 indicates the time when welding by welding robot 100 is finished. In this example, although the example which displays the waveform of a welding current is shown, the displayed waveform may be related to a welding voltage, and the waveform of both a welding current and a welding voltage may be displayed.

  As shown in FIG. 3, first, analysis conditions are set by the welding waveform analyzer 11 (S11). This analysis condition is, for example, based on the waveform stored in the current / voltage storage unit DB3 (that is, the waveform of at least one of the welding voltage and the welding current), the welding condition created in advance, etc. And setting an analysis interval from the start of analysis to the end of analysis. FIG. 5 shows an example where the time from t2 to t5 is set as the analysis section S, and the threshold R is set as the welding current value for determining welding abnormality.

  After setting the analysis conditions, the welding robot 100 welds the workpiece 200 based on the program stored in the program storage unit DB1 (S12).

  During welding by the welding robot 100, the welding waveform analyzer 11 compares the analysis conditions set in step S11 with the waveform of the welding current acquired by the acquiring unit 12 (S13). In the present embodiment, in the waveform of the welding current acquired by the acquiring unit 12, there is a portion in the waveform of the analysis section (the section from time t2 to time t5 shown in FIG. 5) satisfying the welding abnormality condition. It is determined by the welding waveform analyzer 11 (that is, whether there is a portion that satisfies the condition less than the threshold R). In the case where the portion below the threshold R is not detected by the welding waveform analyzer 11 among the waveforms of the welding current acquired by the acquiring unit 12, that is, in the case of no welding abnormality (S13 (NO)), the process returns to S12. If a portion less than the threshold R is detected by the welding waveform analyzer 11, that is, if there is welding abnormality (S13 (YES)), the process proceeds to S14.

  When a portion less than the threshold R in the waveform of the welding current is detected by the welding waveform analyzer 11, the welding waveform analyzer 11 outputs a marking command to the marking mechanism 120 (S14). The marking mechanism 120 that has received the output marking command executes the marking process on the workpiece 200 (S15). After execution of the marking process, the above-described processes after S12 are repeated.

  The marking process described above will be further described with reference to FIG. First, the marking control unit 122 of the marking mechanism 120 receives the marking command output from the welding waveform analysis device 11 (S151).

  Next, the marking control unit 122 controls the amount of liquid applied from the marking device 121 to the workpiece 200 (injection amount), the position to be applied (injection coordinates), and the application time (injection time) based on the received marking command. Is determined (S152).

  Next, the marking control unit 122 outputs a marking command to the marking device 121 based on the determined ejection amount, ejection coordinates, and ejection time (S153), and the marking device 121 applies the marking to the workpiece 200. In the example shown in FIG. 5, the workpiece 200 is marked with liquid from time t3 to time t4 satisfying the condition less than the threshold R in the waveform of the welding current during the welding period (welding start time t1 to welding end time t6) Ru.

  As described above, in the present embodiment, when it is determined by the welding waveform analysis device 11 that the waveform of the welding current satisfies less than the threshold R (that is, the condition of welding abnormality is satisfied), the marking device 121 Marking to 200 is performed during welding. By confirming the marking after welding, it is possible to easily identify the location of the welding abnormality actually produced on the workpiece 200. In addition, in order to identify the location of welding abnormality actually occurring in the workpiece 200, for example, there is no need for a process of following the movement trajectory of the welding robot. It is possible to identify the location of the welding abnormality that has occurred in the workpiece 200.

  In the embodiment described above, the marking process is not limited to the application of the liquid marking to the work 200 only during the period from time t3 to time t4. For example, from the time t3 to the time t4 when a liquid of a specific color (for example, yellow) is marked on the workpiece 200 in the entire period during welding by the welding robot 100 and the waveform of the welding current satisfies the condition below threshold R during welding. A marking of a color different from the specific color (for example, red) may be provided. As described above, by using the color of the liquid while applying the liquid to the work 200 for the entire period of welding, the welding abnormality occurred in the work 200 while specifying all the parts actually welded to the work 200. Can also be identified.

  Moreover, a plurality of threshold values for determining welding abnormality are set as analysis conditions, and liquids of different colors are selectively used according to a plurality of commands output from the welding waveform analysis device 11 to apply markings by the marking device 121 to the work 200 You may More specifically, based on the waveform stored in the current / voltage storage unit DB3, the threshold of the welding current according to the weight of the welding abnormality is set in a plurality of stages (for example, the threshold of the welding current for determining a mild welding abnormality) The threshold of the welding current for determining severe welding abnormalities is set as R2), and the different colors of liquid are used according to the period in which the welding current thresholds R1 and R2 set in the multiple stages are satisfied. The marking device 121 may be controlled to apply marking (for example, a period in which the condition less than the threshold R1 is satisfied is yellow, and a period in which the condition less than the threshold R1 is satisfied is red).

  Moreover, the marking by the marking device 121 is not limited to the liquid. For example, marking with an adhesive such as a tape may be used in a portion of the waveform of the welding current that satisfies the condition less than the threshold R. Alternatively, the marking including the printing may be used by using a marking device 121 having a printing function indicating a portion of the welding abnormality or a content of the welding abnormality which satisfies the condition less than the threshold R in the waveform of the welding current.

  In the example described above, the welding voltage was determined using the measured value of the welding current as a threshold value for determining welding abnormality by the welding waveform analyzer 11, but the welding voltage has a predetermined value using the measured value of the welding voltage. It is good also as an aspect which gives marking to a work on condition of having been filled.

  The embodiments described above are for the purpose of facilitating the understanding of the present invention, and are not for the purpose of limiting the present invention. The elements included in the embodiment and the arrangement, the material, the conditions, the shape, the size, and the like of the elements are not limited to those illustrated, and can be changed as appropriate. In addition, configurations shown in different embodiments can be partially substituted or combined with each other.

  DESCRIPTION OF SYMBOLS 1 ... Robot control apparatus, 2 ... Analysis part, 3 ... Execution part, 4 ... Welding control part, 5 ... Servo control part, 11 ... Welding waveform analysis apparatus, 12 ... Acquisition part, 13 ... Display part, 20 ... Welding power supply, 30 Current / voltage measuring device 100 Welding robot 101 Servomotor 102 Welding torch 110 Welding wire 120 Marking mechanism 121 Marking device 122 Marking control unit 200 Work piece 300 Welding base, DB1 ... program storage unit, DB2 ... welding condition storage unit, DB3 ... current / voltage storage unit, R ... threshold value

Claims (5)

A welding robot system comprising a welding robot and a robot control unit for controlling the welding robot, the welding robot system comprising:
The robot control unit
An acquisition unit configured to acquire a waveform of at least one of a welding voltage and a welding current of welding performed by the welding robot;
And a welding waveform analysis unit that analyzes a waveform of a predetermined welding section among the waveforms acquired by the acquisition unit;
The welding robot is
A welding robot system comprising a marking mechanism for applying markings to a workpiece during welding by the welding robot when it is determined by the welding waveform analysis unit that the waveform of the welding section satisfies the welding abnormality condition. The robot control unit includes a storage unit that stores the waveform acquired by the acquisition unit.
The welding abnormality condition is that the measured value of the welding current acquired by the acquisition unit in the welding section is less than a threshold determined based on the waveform stored in the storage unit.
The welding robot system according to claim 1. The marking mechanism includes a marking device attached to an arm of the welding robot, and a marking control unit that controls the marking device based on a command output from the welding waveform analysis unit.
The marking control unit controls the marking device to apply a liquid capable of identifying a portion of the portion welded by the welding robot that satisfies the condition of the welding abnormality to the workpiece.
The welding robot system according to claim 1 or 2. The marking control unit controls the marking device to apply the different types of liquids to the workpiece based on a command output from the welding waveform analysis unit.
The welding robot system according to claim 3. Performing welding by the welding robot according to a work program including welding construction conditions;
Acquiring at least one waveform of a welding voltage and a welding current of welding performed by the welding robot by an acquiring unit;
Analyzing the waveform acquired by the acquisition unit by a welding waveform analysis unit;
Marking the object to be welded with a marking device during welding by the welding robot when it is determined by the welding waveform analysis unit that the waveform acquired by the acquisition unit satisfies the condition of welding abnormality; ,
How to identify welding anomaly locations, including