JP5759737B2 - Control method and control system for pulse TIG welding robot - Google Patents

Description

  The present invention relates to a control method and a control system for a pulse TIG welding robot.

  When pulse TIG welding is automated, the workpiece is distorted by welding heat generated in the welding process, and the distance between the welding torch and the workpiece may change, and stable welding may not be possible. On the other hand, there has been proposed a scanning arc sensor that can keep a constant distance between the welding torch and the workpiece by using a voltage value in a peak voltage section extracted from a pulse voltage value of TIG welding. Patent Document 1 proposes a method of extracting a peak voltage value by using the rising and falling edges of the TIG pulse voltage value of TIG welding.

Patent Document 2 proposes a method of manually setting a reference voltage serving as a threshold value in order to determine whether the voltage value is a peak voltage value or a base voltage value.
In these methods, copying can be performed in the peak voltage section, but copying control using the voltage value in the base voltage section cannot be performed. In some cases, such as when the welding length is long and the welding speed is slow, the base voltage section is set long in order to avoid thermal distortion caused by welding. Further, depending on the work environment and welding conditions, the base voltage value may be output more stably than the peak voltage value. In this way, there are cases where the scanning control with higher accuracy can be performed by using the base voltage value than the peak voltage value.

  Moreover, although the tip of the TIG electrode is a non-consumable electrode, the tip of the electrode may be rounded due to welding during actual welding, and the peak voltage value extracted from the pulse TIG welding voltage value may be small. . In this case, since the change in the voltage value between the peak and the base becomes small, in Patent Document 1, it is not possible to extract the rising and falling edges of the arc, and there is a possibility that the voltage value used for copying cannot be collected. Control is disabled. In such a case, in order to extract a correct voltage value, a high-performance AD converter is required, which increases the cost. In Patent Document 2, it is determined that the voltage is lower than the reference voltage for determining whether the peak voltage interval or the base voltage interval is the base voltage value. Therefore, the necessary voltage value cannot be collected and the copying control is not performed. It becomes a state.

Japanese Patent Publication No. 61-78570 JP 2010-125461 A

As described above, Patent Documents 1 and 2 are scanning controls using a peak voltage section, and are not considered to perform scanning control using a base voltage section.
Further, in Patent Documents 1 and 2, when the peak voltage value of the TIG pulse voltage becomes small and the difference between the peak and base voltage values becomes small, the voltage value necessary for copying cannot be extracted and the copying control can be performed. There is no problem.

  The object of the present invention is to be able to select either the peak voltage section or the base voltage section, so that not only the peak voltage section of TIG welding but also the base voltage section can be used to perform the copying control, and the welding environment can be further improved. It is an object to provide a control method and a control system of a pulse TIG welding robot capable of performing adaptive copying.

  Another object of the present invention is that the peak voltage section and base voltage section of the TIG pulse voltage can be automatically and reliably determined, and there is no manual input error or extraction failure due to voltage drop. It is an object of the present invention to provide a control method and a control system for a pulse TIG welding robot capable of realizing an easy apparatus and capable of reliable scanning control.

In order to solve the above problems, the invention of claim 1 includes a TIG welding power source that generates a pulse signal and applies an actual welding voltage to a base material via a welding torch in synchronization with the pulse signal. In the control method of the pulse TIG welding robot that performs the pulse TIG welding by applying the actual welding voltage, by setting the setting means provided in the pulse TIG welding robot, as the designated voltage section used for the copying control, a first step of setting one of the intervals of the peak voltage section or base voltage sections of the pulse signal, and a second step of determining a peak voltage section and the base voltage section of the pulse signal, in the set specified voltage sections A third step of extracting an actual welding voltage for each sampling period; and the extracted actual in the specified voltage section. A calculation step for obtaining an operation direction and a torch operation amount of the welding torch based on a difference between an average voltage of the contact voltage and a preset reference voltage, and the welding based on the operation direction and the torch operation amount of the welding torch. The gist of the control method of the pulse TIG welding robot is characterized by comprising a control step of controlling the robot to control the distance between the welding torch and the base material to control the copying.

The invention of claim 2 includes a TIG welding power source that generates a pulse signal and applies an actual welding voltage to a base material via a welding torch in synchronization with the pulse signal, and the pulse TIG is applied by applying the actual welding voltage. In the control method of the pulse TIG welding robot for performing welding, by setting the setting means provided in the pulse TIG welding robot, the peak voltage interval or the base voltage of the pulse signal is set as the specified voltage interval used for the copying control. A setting step for setting one of the sections , and a voltage obtained by averaging the value of the actual welding voltage (hereinafter referred to as the actual welding voltage) sampled in a sampling period shorter than the pulse period of the pulse signal in the time direction. Obtaining an interval determination reference value; and based on the voltage interval determination reference value, the actual welding voltage is the pulse In the determination step of determining which voltage section of the peak voltage section or base voltage section of the signal, among the actual welding voltage determined to belong to the peak voltage section or the base voltage section in the determination step, An extraction step for extracting an actual welding voltage belonging to the set specified voltage section, and a difference between an average voltage of the extracted actual welding voltage in the specified voltage section and a preset reference voltage. A calculation step for obtaining an operation direction and a torch operation amount, and a control of the welding robot based on the operation direction and the torch operation amount of the welding torch to control a distance between the welding torch and the base material to perform the scanning control. The gist of the control method of the pulse TIG welding robot is characterized by having a control step.

  The invention of claim 3 includes a TIG welding power source that generates a pulse signal and applies an actual welding voltage to a base material via a welding torch in synchronization with the pulse signal, and the pulse TIG is applied by applying the actual welding voltage. In a control system for a pulse TIG welding robot that performs welding, a setting unit that sets either a peak voltage interval or a base voltage interval in the actual welding voltage as a specified voltage interval used for scanning control, and a peak of the pulse signal A determination means for determining a voltage interval and a base voltage interval; an extraction means for extracting an actual welding voltage in the set specified voltage interval for each sampling period; and an average voltage of the extracted actual welding voltage in the specified voltage interval And a calculating means for obtaining an operation direction and a torch operation amount of the welding torch based on a difference between the reference voltage and a preset reference voltage; A pulse TIG comprising robot control means for controlling the welding robot based on an operation direction and a torch operation amount of the welding torch to control a distance between the welding torch and the base material to perform the copying control. The gist of the control system is a welding robot.

  The invention of claim 4 includes a TIG welding power source that generates a pulse signal and applies an actual welding voltage to a base material via a welding torch in synchronization with the pulse signal, and the pulse TIG is applied by applying the actual welding voltage. In a control system for a pulse TIG welding robot that performs welding, setting means for setting a peak voltage section or a base voltage section as a designated voltage section used for scanning control, and a sampling period shorter than the pulse period of the pulse signal are sampled. In addition, a time direction averaging means for obtaining a voltage section determination reference value by averaging the value of the actual welding voltage (hereinafter referred to as an actual welding voltage) in the time direction, and the actual welding voltage is calculated based on the voltage section determination reference value. Determining means for determining whether the pulse signal belongs to a peak voltage interval or a base voltage interval of the pulse signal; and the determination Extracting means for extracting an actual welding voltage belonging to the set designated voltage section from among the actual welding voltages determined to belong to the peak voltage section or the base voltage section in the stage, and the extraction in the designated voltage section Calculating means for obtaining an operation direction and a torch operation amount of the welding torch based on a difference between an average voltage of the actual welding voltage and a preset reference voltage; and based on the operation direction and the torch operation amount of the welding torch The gist of the control system for the pulse TIG welding robot is characterized by comprising a robot control means for controlling the scanning by controlling the welding robot to control the distance between the welding torch and the base material.

  According to the first and second aspects of the present invention, since not only the peak voltage interval of TIG welding but also the copying control can be performed using the base voltage interval, it is possible to perform copying more adapted to the welding environment. The control method of the pulse TIG welding robot which can be provided can be provided.

  In addition, according to the first and second aspects of the present invention, since the peak voltage interval and the base voltage interval of the TIG pulse voltage can be automatically and reliably determined, the peak voltage interval and the base voltage interval can be determined. There is no need to manually input a reference value, and there is no manual input error of the reference value, and no extraction failure due to a voltage drop due to the input error, so that an easier-to-use device can be realized and reliable scanning control is performed. It is possible to provide a control method of a pulse TIG welding robot that can perform the above-described process.

  According to the third and fourth aspects of the present invention, it is possible to perform scanning control using not only the peak voltage section of TIG welding but also the base voltage section, so that scanning suitable for the welding environment can be performed. A control system for a pulse TIG welding robot can be provided.

  According to the invention of claim 3 and claim 4, since the peak voltage section and base voltage section of the TIG pulse voltage can be automatically and reliably determined, the peak voltage section and base voltage section are determined. There is no need to manually input a reference value, and there is no manual input error of the reference value, and no extraction failure due to a voltage drop due to the input error, so that an easier-to-use device can be realized and reliable scanning control is performed. Therefore, it is possible to provide a control system for a pulse TIG welding robot that can achieve the above.

The electric block diagram of the control system of the pulse TIG welding robot of a 1st embodiment. (A) is a flowchart of the determination program of the peak voltage section and base voltage section of the pulse signal executed by the external pulse signal reception discriminator of the first embodiment, and (b) is a flowchart of the voltage extraction program executed by the voltage extractor. . Explanatory drawing which shows the relationship of the height of a pulse signal, an actual welding voltage, and the welding torch when copying in the peak voltage area of a TIG pulse signal. Explanatory drawing which shows the relationship between the height of a pulse signal, an actual welding voltage, and a welding torch when copying in the base voltage area of a TIG pulse signal. The electric block diagram of the control system of the pulse TIG welding robot of a 2nd embodiment. (A) is a flowchart of a determination program executed by the peak / base voltage section determiner of the second embodiment, and (b) is a flowchart of a voltage extraction program executed by the voltage extractor. Explanatory drawing which shows the relationship between the filtering voltage, the actual welding voltage, and the height of a welding torch when copying in the peak voltage area of the TIG pulse signal in 2nd Embodiment. Explanatory drawing which shows the relationship between the filtering voltage, actual welding voltage, and the height of a welding torch when copying in the base voltage area of the TIG pulse signal in 2nd Embodiment.

(First embodiment)
Hereinafter, a control method and a control system (hereinafter simply referred to as a system) of a pulse TIG welding robot according to a first embodiment embodying the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the system supplies power to a welding robot manipulator (hereinafter simply referred to as a welding robot) 10 having a welding torch 11, a robot controller 20 that controls the welding robot 10, and the welding torch 11. A TIG welding power source 30 and a TIG arc sensor 50 are provided. The TIG welding power source 30 supplies power to the welding torch 11 attached to the tip of the welding robot 10. The workpiece W as a base material is electrically connected via a TIG welding power source 30.

  The robot controller 20 is electrically connected to the TIG arc sensor 50 and can communicate various control information. The robot controller 20 includes a peak / base designated voltage section selector 25 as setting means. The operator performs the TIG welding for the peak base designated voltage section selector 25 so as to adapt to the welding environment by operating a portable operating device (teach pendant) (not shown) connected to the robot controller 20 so as to be communicable. A setting operation is performed in advance before the first step (first step). Thus, either the peak voltage interval or the base voltage interval of the pulse signal P1 can be set as a designated voltage interval for performing welding line scanning control (hereinafter simply referred to as scanning control). The pulse signal P <b> 1 is generated by the TIG welding power source 30 based on the pulse frequency / pulse ratio (duty ratio) set by the robot controller 20. In the peak / base designated voltage section selector 25, the set designated voltage section is transmitted to the TIG arc sensor 50.

  The robot controller 20 can communicate various control information with the welding robot 10, performs pulse TIG welding according to the teaching program stored in the robot controller 20, and controls signals from the TIG arc sensor 50. Thus, the welding line scanning control (hereinafter simply referred to as scanning control) is performed while correcting the position of the welding torch 11, that is, the distance to the workpiece W.

  As shown in FIG. 1, the TIG arc sensor 50 includes a voltage measuring device 51, an external pulse signal reception discriminator 52, a voltage extractor 53, an extracted voltage value averaging processor 54, an arc reference voltage setting device 55, and a differential voltage calculator 56. , A torch motion direction determination unit 57, and a torch motion amount calculator 60.

  In the configuration of the TIG arc sensor 50, the external pulse signal reception discriminator 52, the voltage extractor 53, the extracted voltage value averaging processor 54, the arc reference voltage setting unit 55, the differential voltage calculator 56, excluding the voltage measuring device 51, The torch motion direction determination unit 57 and the torch motion amount calculator 60 may be configured by a computer or may be configured as individual devices.

  In the system of the present embodiment, the external pulse signal reception discriminator 52 corresponds to the determination means of claim 1 and the voltage extractor 53 corresponds to the extraction means. The extracted voltage value averaging processor 54, the difference voltage calculator 56, the torch operation direction determination unit 57, and the operation amount calculator 60 correspond to calculation means. The robot control device 20 corresponds to robot control means.

  In the present embodiment, the voltage measuring device 51 corresponds to voltage measuring means. The extracted voltage value averaging processor 54 corresponds to extracted voltage value averaging means, and the arc reference voltage setting device 55 corresponds to reference voltage setting means. The differential voltage calculator 56 corresponds to a differential voltage determination unit, and the torch operation direction determination unit 57 corresponds to a torch operation direction determination unit. The operation amount calculator 60 corresponds to the operation amount calculation means of the welding torch 11.

(Operation of the embodiment)
The operation of the system configured as described above will be described with reference to FIGS.
In TIG welding, current and voltage are output between the welding torch 11 and the workpiece W by the TIG welding power source 30 based on the pulse frequency and pulse ratio (duty ratio) of the welding current and welding voltage set by the robot controller 20. Welding is performed. As described above, when the welding torch 11 is performing pulse TIG welding on the workpiece W by welding line tracing, the voltage measuring device 51 of the TIG arc sensor 50 is applied to the welding torch 11 from the TIG welding power source 30. The welding voltage V1 is measured at a measurement cycle (that is, a sampling cycle). This sampling period is a period much shorter than the pulse period of the power applied to the welding torch 11 by the TIG welding power source 30. The voltage measuring device 51 outputs the actual welding voltage V <b> 1 measured at the sampling cycle to the voltage extractor 53.

  The TIG welding power source 30 generates a pulse signal P1 based on the pulse frequency / pulse ratio (duty ratio) set by the robot controller 20, and the external pulse signal reception discriminator 52 receives the pulse signal P1. .

  When the received pulse signal P1 indicates a peak, the external pulse signal reception discriminator 52 determines that it is a peak voltage interval, and if it indicates a base, it determines that it is a base voltage interval (second step). More specifically, FIG. 2A shows a pulse signal that the external pulse signal reception discriminator 52 executes in the same cycle as the sampling cycle when the external pulse signal reception discriminator 52 is configured by a computer. It is a flowchart of the determination program of a peak voltage area and a base voltage area.

  In S10, the external pulse signal reception discriminator 52 determines whether or not the received pulse signal P1 has a peak value. If the received pulse signal P1 has a peak value, in S12, the pulse signal P1 just received is the peak voltage. After determining that it is a section and setting the determination result to ON (that is, “1”), the process proceeds to S14. On the other hand, if it is determined in S10 that the peak value is not reached, it is determined in S16 that it is the base voltage section, OFF (that is, “0”) is set in the determination result, and the process proceeds to S14. In S <b> 14, the external pulse signal reception discriminator 52 transmits the determination result of S <b> 12 or S <b> 16 to the voltage extractor 53. Note that the settings of ON (1) and OFF (0), which are the determination results of the peak voltage section and the base voltage section, may be reversed, that is, inverted and output. In this case, for example, the external pulse signal reception discriminator is changed by changing the output setting of the external pulse signal reception discriminator 52 from the robot controller 20 by the setting change operation of the portable operating device (teach pendant) not shown. The output of the determination result from 52 to the voltage extractor 53 can be inverted.

  The voltage extractor 53 extracts the actual welding voltage in the specified voltage section set by the peak / base specified voltage section selector 25 at the same cycle as the sampling period from the actual welding voltage V1 input from the voltage measuring device 51. FIG. 2B is a flowchart of a voltage extraction program that is executed at each sampling period when the voltage extractor 53 is configured by a computer.

  As shown in the figure, in S20, the voltage extractor 53 determines whether or not the specified voltage section set by the peak / base specified voltage section selector 25 of the robot controller 20 is a peak voltage section, that is, It is determined whether or not the peak voltage section is used.

  When the specified voltage section transmitted from the robot controller 20 is set as the base voltage section, the voltage extractor 53 proceeds from S20 to S28. In S28, the voltage extractor 53 determines whether or not the determination result transmitted from the external pulse signal reception determination unit 52 is OFF (0).

  In S28, when the determination result is not OFF (0), the voltage extractor 53 sets the determination in S28 to “NO”, and ends this flowchart once. That is, in this case, since it is determined in S20 that the designated voltage section is set to use the base voltage section, if the determination result is not OFF (0), the actual welding voltage V1 is in the peak voltage section. In this section, the actual welding voltage V1 is not used for the copying control. In S28, when the determination result is OFF (0), the voltage extractor 53 sets the determination in S28 to “YES”, and proceeds to S24.

In S20, when the specified voltage section transmitted from the robot controller 20 is set to the peak voltage section, the voltage extractor 53 proceeds to S22.
In S22, the voltage extractor 53 determines whether or not the determination result transmitted from the external pulse signal reception determination unit 52 is ON (1).

  In S22, when the determination result is not ON (1), the voltage extractor 53 sets the determination in S22 to “NO”, and once ends this flowchart. That is, in this case, since it is determined in S20 that the specified voltage section is set to use the peak voltage section, if the determination result is not ON (1), the actual welding voltage V1 is set to the base voltage section. In this section, the actual welding voltage V1 is not used for the copying control. In S22, when the determination result is ON (1), the voltage extractor 53 sets the determination in S22 to “YES”, and proceeds to S24.

  In S24, when it is determined “YES” in S28, the voltage extractor 53 extracts the actual welding voltage V1 whose determination result is OFF (0), and stores (saves) it as a copying voltage V2 in a memory (not shown). (Third step). Alternatively, in S24, if the voltage extractor 53 determines “YES” in S22, it extracts the actual welding voltage V1 whose determination result is OFF (0) and stores it as a copying voltage V2 in a memory (not shown) ( (Save) (third step).

  The extracted voltage value averaging processor 54 shown in FIG. 1 averages the scanning voltage V2 stored in the memory (not shown) by the voltage extractor 53 to obtain an average voltage M. Although this averaging process can mention a moving average, for example, it is not limited to a moving average, The other well-known average process may be sufficient.

  The difference voltage calculator 56 calculates the difference voltage based on the arc reference voltage K as a reference voltage preset by the arc reference voltage setter 55 and the average voltage M obtained by the extracted voltage value averaging processor 54. . Here, if the average voltage M> the arc reference voltage K, the difference voltage is a positive value, and if the average voltage M <the arc reference voltage K, the difference voltage is −. Further, when the average voltage M = the arc reference voltage K, the differential voltage is zero. Based on the +,-, and 0, the torch operation direction determination unit 57 determines the operation direction of the welding torch 11 for each control cycle.

  That is, in the case of +, since the average voltage M is higher than the arc reference voltage K, the direction approaching the workpiece W is the operation direction, and in the case of-, the average voltage M is lower than the arc reference voltage K. The direction approaching W is the operation direction. In the case of 0, the torch operation direction is not changed.

  The torch operation amount calculator 60 calculates a torch operation amount as a position correction amount of the welding torch 11. The torch operation amount may be calculated by any method of proportional control of the differential voltage or proportional integral control of the differential voltage. The processing performed by the differential voltage calculator 56, the torch motion direction determiner 57, and the torch motion amount calculator 60 corresponds to a calculation step.

  Then, the torch motion amount and the torch motion direction by the motion amount calculator 60 are output to the robot control device 20, so that the robot control device 20 can determine the welding robot 10 based on the torch motion amount and the torch motion direction. , And the distance between the welding torch 11 and the workpiece W (base material) is controlled by moving the welding torch 11. The control of the robot control device 20 corresponds to a control step.

  FIG. 3 shows the pulse signal P1, the arc reference voltage K, and the actual welding voltage V1 when the designated voltage section is set to the peak voltage section of the pulse signal P1, and the copying of the welding torch 11 in the peak voltage section. The case where control is performed is shown. In the figure, the vertical axis represents voltage and height, and the horizontal axis is the time axis.

  FIG. 4 shows the pulse signal P1, the arc reference voltage K, and the actual welding voltage V1 when the designated voltage section is set to the base voltage section of the pulse signal P1, and the welding torch 11 in the base voltage section. The case where the copying control is performed is shown. In the figure, the vertical axis represents voltage and height, and the horizontal axis is the time axis. In both figures, “peak” indicates a peak voltage interval, and “base” indicates a base voltage interval.

  In the case of FIG. 3, the copying voltage V2 is extracted in the peak voltage section and the average voltage M is calculated. In this peak voltage section, the copying control of the height (separation distance) of the welding torch 11 from the workpiece W (base material) is performed. In the case of FIG. 4, the copying voltage V2 is extracted in the base voltage section and the average voltage M is calculated. Then, in this base voltage section, the copying control of the height (separation distance) of the welding torch 11 from the workpiece W (base material) is performed.

The method and system configured as described above have the following characteristics.
(1) In the control method of the present embodiment, the peak / base specified voltage section selector 25 sets the peak voltage section or base voltage section of the pulse signal P1 as the specified voltage section used for the scanning control (first step) ). Then, the external voltage signal reception discriminator 52 determines the peak voltage interval and the base voltage interval of the pulse signal P1 (second step). Further, the actual welding voltage V1 in the designated voltage section set by the peak / base designated voltage section selector 25 is extracted by the voltage extractor 53 every sampling period (third step). Then, based on the difference between the average voltage M of the extracted actual welding voltage V1 in the specified voltage section and a preset arc reference voltage K (reference voltage), the operation direction and the torch operation amount of the welding torch 11 are obtained ( Calculation step). Further, the welding robot 10 is controlled on the basis of the operation direction and the torch operation amount of the welding torch 11, and the distance between the welding torch 11 and the workpiece W (base material) is controlled to perform copying control (control step).

  Further, the system of the present embodiment includes a peak / base designated voltage section selector 25 (setting means) that sets either the peak voltage section or the base voltage section in the actual welding voltage as the designated voltage section used for the copying control. And an external pulse signal reception discriminator 52 (determination means) for determining the peak voltage interval and the base voltage interval of the pulse signal P1. Further, the system preliminarily sets a voltage extractor 53 (extraction means) that extracts the actual welding voltage V1 in the set designated voltage section for each sampling period, and an average voltage M of the extracted actual welding voltage V1 in the designated voltage section. Based on the difference voltage (difference) from the arc reference voltage K (reference voltage), the extracted voltage value averaging processor 54, the difference voltage calculator 56, and the torch operation direction for obtaining the operation direction and torch operation amount of the welding torch 11 A determination unit 57 and an operation amount calculator 60 (calculation means) are provided. In addition, the system controls the welding robot 10 on the basis of the operation direction and the torch operation amount of the welding torch 11 to control the distance between the welding torch 11 and the workpiece W (base material) to control the robot controller 20 ( Robot control means).

  As a result, according to the control method and system of the present embodiment, it is possible to perform scanning control using not only the peak voltage interval of TIG welding but also the base voltage interval. For this reason, copying adapted to the welding environment can be performed. Further, according to the control method of the present embodiment, the peak voltage base and the base voltage section of the TIG pulse voltage can be automatically and reliably determined by the setting of the peak / base designated voltage section selector 25. There is no need to manually input a reference value for determining the interval and the base voltage interval, and there is no manual input error of the reference value, and no extraction failure due to a voltage drop caused by the input error, making it easier to use. The apparatus can be realized and reliable copying control can be performed.

(Second Embodiment)
Next, the system and control method of the second embodiment will be described with reference to FIGS. In the system of the second embodiment, the same or corresponding components as those of the system of the first embodiment are denoted by the same reference numerals, detailed description thereof is omitted, and different configurations are mainly described.

  As shown in FIG. 5, in the system of the second embodiment, the external pulse signal reception discriminator 52 is omitted in the configuration of the TIG arc sensor 50 of the first embodiment. Instead, a filtered voltage value generator 62 for inputting the actual welding voltage V1 measured by the voltage measuring device 51 at every sampling period is provided, and the output of the filtered voltage value generator 62 is a peak-base voltage interval. The difference from the first embodiment is that it is input to the determiner 64. The output of the peak / base voltage section determiner 64 is input to the voltage extractor 53. Other hardware configurations are the same as those in the first embodiment.

  In the configuration of the TIG arc sensor 50, a filtered voltage value generator 62, a voltage extractor 53, an extracted voltage value averaging processor 54, an arc reference voltage setting device 55, a differential voltage calculator 56, excluding the voltage measuring device 51, The torch motion direction determination unit 57 and the torch motion amount calculator 60 may be configured by a computer or may be configured as individual devices.

  In the system of the present embodiment, the filtered voltage value generator 62 corresponds to time direction averaging means. The peak / base voltage section determiner 64 corresponds to the determination means of claim 2. The voltage extractor 53 corresponds to extraction means. The extracted voltage value averaging processor 54, the difference voltage calculator 56, the torch operation direction determination unit 57, and the operation amount calculator 60 correspond to calculation means. The robot control device 20 corresponds to robot control means.

(Operation of Second Embodiment)
Next, the operation of the second embodiment will be described with reference to FIGS.
First, the operator enters the welding environment by operating a portable operation device (teach pendant) (not shown) connected to the robot control device 20 so as to be communicable with the peak / base designated voltage section selector 25 as the setting means. In order to adapt, the peak / base designated voltage section selector 25 is set in advance before performing TIG welding (setting step).

  When TIG welding is started, the TIG welding power source 30 shown in FIG. 5 generates a pulse signal P1 based on the pulse frequency / pulse ratio (duty ratio) set by the robot controller 20, and the pulse signal P1 Accordingly, electric power is supplied to the welding torch 11. The voltage measuring device 51 of the TIG arc sensor 50 measures at the same sampling period as that in the first embodiment, and outputs the measurement result to the filtered voltage value generator 62.

  The filtered voltage value generator 62 stores the actual welding voltage V1 input from the voltage measuring device 51 in a memory (not shown) and calculates a voltage section determination reference value based on the actual welding voltage V1. That is, the filtered voltage value generator 62 calculates a filtered voltage value V1 '(hereinafter referred to as a filtered voltage) as a voltage section determination reference value. Examples of the calculation method include a processing method using an FIR (Finite Impulse Response) filter and a known method of a moving average processing method, but are not limited to these methods. With these processes, the actual welding voltage V1 measured in the current sampling cycle is averaged in the time direction together with the plurality of actual welding voltages V1 measured in the previous cycle. The filtered voltage V1 'using the FIR filter becomes a delayed voltage value, and the voltage value obtained by the moving average process becomes a moving averaged voltage value. The filtered voltage value generator 62 outputs the calculated filtered voltage V <b> 1 ′ to the peak / base voltage section determiner 64.

The process (step) in the filtered voltage value generator 62 corresponds to a step of averaging the actual welding voltage in the time direction to obtain a voltage section determination reference value.
The peak / base voltage section determiner 64 determines whether the actual welding voltage V1 stored in the memory belongs to the peak voltage section or the base voltage section of the pulse signal P1. FIG. 6A shows a peak voltage section of a pulse signal that the peak / base voltage section determiner 64 executes in the same cycle as the sampling period when the peak / base voltage section determiner 64 is configured by a computer. It is a flowchart of the determination program of a base voltage area. Unlike the first embodiment, the present embodiment does not determine whether the current pulse signal P1 is in the peak voltage interval or the base voltage interval based on the pulse signal P1, but based on the input actual welding voltage V1. Thus, it is characterized in that it is determined whether the current pulse signal P1 is in the peak voltage interval or the base voltage interval.

In S30 shown in FIG. 6A, the peak / base voltage section determiner 64 determines whether or not the actual welding voltage V1 is equal to or higher than the filtered voltage V1 ′.
Here, the reason for determining whether or not the actual welding voltage V1 is equal to or higher than the filtered voltage V1 ′ will be described.

  As shown in FIGS. 7 and 8, the pulse signal P1 (not shown), the peak voltage interval of the actual welding voltage V1, and the base voltage interval are synchronized. When the actual welding voltage V1 is a peak voltage value (voltage value in the peak voltage section), the filtered voltage V1 ′ is smaller than the actual welding voltage V1, and the actual welding voltage V1 is the base voltage value (base voltage section). In this case, the filtered voltage V1 ′ is larger than the actual welding voltage V1.

  Therefore, when the actual welding voltage V1 is equal to or higher than the filtered voltage V1 ′, it is determined in S32 that the pulse signal P1 is in the peak voltage section, and the determination result is set to ON (that is, “1”). Then, the process proceeds to S34. In S30, if the actual welding voltage V1 is less than the filtered voltage V1 ′, the peak / base voltage section determiner 64 determines in S36 that it is a base voltage section, and the determination result is OFF (ie, , “0”) is set, and the process proceeds to S34. In S <b> 34, the peak / base voltage section determiner 64 transmits the determination result of S <b> 32 or S <b> 36 to the voltage extractor 53. Note that the settings of ON (1) and OFF (0), which are the determination results of the peak voltage section and the base voltage section, may be reversed, that is, inverted and output. In this case, for example, by changing the output setting of the peak / base voltage section determiner 64 from the robot controller 20 by a setting changing operation of the portable operation device (teach pendant) (not shown), the peak / base voltage section is changed. The output of the determination result from the determination unit 64 to the voltage extractor 53 can be inverted.

The processing (step) performed by the peak / base voltage section determiner 64 corresponds to the determination step of claim 2.
The voltage extractor 53 extracts the actual welding voltage in the designated voltage section set by the peak / base designated voltage section selector 25 at the same period as the sampling period from the actual welding voltage V1 stored in the memory (not shown). To do. FIG. 6B is a flowchart of a voltage extraction program executed for each sampling period when the voltage extractor 53 is configured by a computer. Note that the flowchart of FIG. 6B is the same as the flowchart of FIG. 2B of the first embodiment, and therefore the step number assigned to each process (step) is S shown in FIG. 2B. 100 is added to the attached number, and the description is omitted.

In the present embodiment, the step of S124 corresponds to the extraction step of claim 2.
The operations of the extracted voltage value averaging processor 54, the arc reference voltage setting device 55, the difference voltage calculator 56, the torch operation direction determination device 57, and the operation amount calculator 60, and the operation of the robot controller 20 are the first implementation. Since it is the same as that of a form, description is abbreviate | omitted. Therefore, the processing performed by the differential voltage calculator 56, the torch motion direction determiner 57, and the torch motion amount calculator 60 corresponds to a calculation step and also corresponds to a control step of the robot control device 20.

  FIG. 7 shows the arc reference voltage K, the actual welding voltage V1, and the filtered voltage V1 ′ when the specified voltage section is set to the peak voltage section of the pulse signal P1 (actual welding voltage), and the peak voltage section. In FIG. 2, the case where the copying control of the welding torch 11 is performed is shown. In the figure, the vertical axis represents voltage and height, and the horizontal axis is the time axis.

  FIG. 8 shows the pulse signal P1, the arc reference voltage K, the actual welding voltage V1, and the filtered voltage V1 ′ when the designated voltage section is set to the base voltage section of the pulse signal P1 (actual welding voltage). In addition, the case where the copying control of the welding torch 11 is performed in the base voltage section is shown. In the figure, the vertical axis represents voltage and height, and the horizontal axis is the time axis. In both figures, “peak” indicates a peak voltage interval, and “base” indicates a base voltage interval.

  In the case of FIG. 7, the copying voltage V2 is extracted in the peak voltage section, and the average voltage M is calculated. In this peak voltage section, the copying control of the height (separation distance) of the welding torch 11 from the workpiece W (base material) is performed. In the case of FIG. 8, the copying voltage V2 is extracted in the base voltage section and the average voltage M is calculated. Then, in this base voltage section, the copying control of the height (separation distance) of the welding torch 11 from the workpiece W (base material) is performed.

The method and system configured as described above have the following characteristics.
(1) The method according to the present embodiment includes a setting step for setting a peak voltage interval or a base voltage interval as a specified voltage interval used for scanning control, and actual welding sampled at a sampling cycle shorter than the pulse cycle of the pulse signal. A step of averaging the voltage V1 in the time direction to obtain a filtered voltage V1 ′ (voltage interval determination reference value); Further, the control method of the present embodiment is based on the filtered voltage V1 ′ and determines whether the actual welding voltage V1 belongs to the peak voltage section or the base voltage section of the pulse signal. 64 includes a process (determination step) performed by 64. Further, a process (extraction) in which the voltage extractor 53 extracts the actual welding voltage V1 belonging to the set specified voltage section among the actual welding voltages V1 determined to belong to the peak voltage section or the base voltage section as the copying voltage V2. Step).

  Then, based on the difference between the average voltage M of the extracted actual welding voltage V1 in the specified voltage section and a preset arc reference voltage K (reference voltage), the operation direction and the torch operation amount of the welding torch 11 are obtained ( Calculation step). Further, the welding robot 10 is controlled on the basis of the operation direction and the torch operation amount of the welding torch 11, and the distance between the welding torch 11 and the workpiece W (base material) is controlled to perform copying control (control step).

  Further, the system of the present embodiment includes a peak / base designated voltage section selector 25 (setting means) that sets either the peak voltage section or the base voltage section in the actual welding voltage as the designated voltage section used for the copying control. And a filtered voltage value generator 62 (time direction averaging means) that averages the actual welding voltage V1 sampled at a sampling period shorter than the pulse period of the pulse signal in the time direction to obtain a filtered voltage V1 ′. .

  The system also determines a peak / base voltage section determiner 64 (determining whether the actual welding voltage V1 belongs to the peak voltage section or the base voltage section of the pulse signal based on the filtered voltage V1 ′. Means). Further, the system extracts the actual welding voltage V1 belonging to the set designated voltage section from the actual welding voltage V1 determined to belong to the peak voltage section or the base voltage section by the peak / base voltage section determination unit 64. A voltage extractor 53 (extraction means) is provided. Further, the system determines the operation direction of the welding torch 11 based on the difference voltage (difference) between the average voltage M of the actual welding voltage V1 extracted in the specified voltage section and a preset arc reference voltage K (reference voltage). An extraction voltage value averaging processor 54 for obtaining a torch operation amount, a differential voltage calculator 56, a torch operation direction determination device 57, and an operation amount calculator 60 (calculation means) are provided. In addition, the system controls the welding robot 10 on the basis of the operation direction and the torch operation amount of the welding torch 11 to control the distance between the welding torch 11 and the workpiece W (base material) to control the robot controller 20 ( Robot control means). As a result, also in the second embodiment, the same effect as the action described in the above (1) of the first embodiment is obtained.

In addition, embodiment of this invention is not limited to the said embodiment, You may change as follows.
In the above-described embodiment, the welding robot 10 is a welding robot having a six-axis joint, but is not limited to six axes. For example, the welding robot may have 5 axes, or 7 axes or more.

  The TIG arc sensor 50 is separate from the robot controller 20, but may be built in the robot controller 20.

10 ... welding robot, 11 ... welding torch,
20 ... Robot control device (robot control means),
25. Peak / base specified voltage section selector (setting means),
30 ... TIG welding power source,
50 ... TIG arc sensor,
51 ... Voltage measuring device (voltage measuring means),
52 ... External pulse signal reception discriminator (determination means),
53 ... Voltage extractor (extraction means),
54 ... Extracted voltage value averaging processor,
55... Arc reference voltage setting device (reference voltage setting means)
56: Differential voltage calculator,
57 ... Torch motion direction determiner,
60... Operation amount calculator (constituting calculation means together with the extracted voltage value averaging processor, the difference voltage calculator, and the torch operation direction determiner),
62 ... Filtered voltage value generator (time direction averaging means),
64... Peak / base voltage section determiner (determination means)
W ... Work (base material).

Claims (4)

A pulse TIG welding robot that includes a TIG welding power source that generates a pulse signal and applies an actual welding voltage to a base material via a welding torch in synchronization with the pulse signal, and performs pulse TIG welding by applying the actual welding voltage In the control method of
A first step of setting one of a peak voltage section and a base voltage section of the pulse signal as a specified voltage section used for the scanning control by setting a setting means provided in the pulse TIG welding robot. A second step of determining a peak voltage section and a base voltage section of the pulse signal, a third step of extracting an actual welding voltage in the set designated voltage section for each sampling period, and the step in the designated voltage section Based on the difference between the extracted average voltage of the actual welding voltage and a preset reference voltage, a calculation step of obtaining the operation direction and torch operation amount of the welding torch, and the operation direction and torch operation amount of the welding torch And controlling the welding robot to control the distance between the welding torch and the base material to control the copying. The method of pulse TIG welding robot, characterized in that it comprises a-up. A pulse TIG welding robot that includes a TIG welding power source that generates a pulse signal and applies an actual welding voltage to a base material via a welding torch in synchronization with the pulse signal, and performs pulse TIG welding by applying the actual welding voltage In the control method of
A setting step of setting one of a peak voltage section and a base voltage section of the pulse signal as a specified voltage section used for scanning control by performing setting operation on a setting means provided in the pulse TIG welding robot ; A step of averaging a value of the actual welding voltage (hereinafter referred to as an actual welding voltage) sampled at a sampling cycle shorter than a pulse cycle of the pulse signal in a time direction to obtain a voltage interval determination reference value; and the voltage interval A determination step of determining whether the actual welding voltage belongs to a peak voltage interval or a base voltage interval of the pulse signal based on a determination reference value, and the peak voltage interval or the base voltage in the determination step Of the actual welding voltages determined to belong to the section, the actual welding voltage belonging to the set specified voltage section An extraction step for extracting the welding torch movement direction and a torch movement amount based on a difference between an average voltage of the extracted actual welding voltage and a preset reference voltage in the specified voltage section; Pulse TIG welding characterized by having a control step of controlling the welding robot based on an operation direction and a torch operation amount of the welding torch to control a distance between the welding torch and the base material to control the copying. Robot control method. A pulse TIG welding robot that includes a TIG welding power source that generates a pulse signal and applies an actual welding voltage to a base material via a welding torch in synchronization with the pulse signal, and performs pulse TIG welding by applying the actual welding voltage In the control system of
Setting means for setting either the peak voltage section or the base voltage section in the actual welding voltage as the designated voltage section used for the scanning control; and a determination means for determining the peak voltage section and the base voltage section of the pulse signal; An extraction means for extracting an actual welding voltage in the set specified voltage section every sampling period, and a difference between an average voltage of the extracted actual welding voltage in the specified voltage section and a preset reference voltage And calculating means for obtaining the operation direction and torch operation amount of the welding torch, and controlling the distance between the welding torch and the base material by controlling the welding robot based on the operation direction and torch operation amount of the welding torch. And a control system for the pulse TIG welding robot, characterized by comprising robot control means for controlling the copying. A pulse TIG welding robot that includes a TIG welding power source that generates a pulse signal and applies an actual welding voltage to a base material via a welding torch in synchronization with the pulse signal, and performs pulse TIG welding by applying the actual welding voltage In the control system of
Setting means for setting a peak voltage interval or a base voltage interval as the designated voltage interval used for the scanning control, and the value of the actual welding voltage sampled at a sampling cycle shorter than the pulse cycle of the pulse signal (hereinafter referred to as actual welding) Time direction averaging means for averaging voltage in the time direction to obtain a voltage section judgment reference value, and based on the voltage section judgment reference value, the actual welding voltage is a peak voltage section or base voltage section of the pulse signal. Of the actual welding voltage determined to belong to the peak voltage section or the base voltage section by the determination means and the set specified voltage section Extraction means for extracting an actual welding voltage, an average voltage of the extracted actual welding voltage in the specified voltage section, and a preset reference voltage Calculating means for obtaining the operation direction and torch operation amount of the welding torch on the basis of, and controlling the welding robot on the basis of the operation direction and torch operation amount of the welding torch to determine the distance between the welding torch and the base material A control system for a pulse TIG welding robot, characterized by comprising robot control means for controlling and performing the copying control.

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