JPH0580312B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to an arc welding control device that can always obtain a correct output value for a set value. Prior art In general, in arc welding equipment, the output current value,
The voltage value, welding speed, etc. are set, and the output value is fed back to the set value to form a closed loop to obtain the desired value.
However, in such a feedback control system, if the applied welding method, welding equipment, material, etc. change, the actual output value will change variously for the same setting position of the output setting device, and it is impossible to obtain the same value. Therefore, it was not possible to attach a correct direct reading scale to the output setting device. For example, in consumable electrode arc welding using a power source with constant voltage characteristics,
The electrode wire is fed at a substantially constant speed, and since the welding current is proportional to this wire feeding speed, the wire feeding speed is commanded as a signal for setting the welding current.
By keeping the wire feeding speed at this set value, a welding current having a value such that "wire feeding amount=wire melting amount" flows. In this way, the welding current is determined by the wire feed rate, so if the material or diameter of the wire is changed, the current required for the same amount of melting will naturally change, so even for the same feed rate, a completely different Current will flow. Furthermore, even if these external factors are the same, the output fluctuation rate of the welding power source and wire feed speed is not constant depending on the magnitude of the output value, so if the output voltage value differs, the same wire feed speed However, the welding current will have a different value. The above phenomenon can be solved by configuring a feedback control system to determine the wire feeding speed based on the difference between the output current value and the set value, rather than keeping the wire feeding speed constant, but in arc welding The welding current has extremely large changes, and it is very difficult to detect this and provide feedback to the wire feeding speed for stable control. In order to stabilize this, it would be possible to slow down the response speed of the feedback signal system so that the control system operates according to the average value, but the necessary response speed would not be obtained by that much, and as a result, becomes unsatisfactory. On the other hand, when performing open-loop control without any feedback on the output, the response speed and stability can be sufficiently ensured, but the output set value and the actual output value are completely different, and even if a scale is provided on the setting device, It is only a guideline. Furthermore, when an output setting signal is supplied from another device such as a large welding device or a welding robot where the output setting device, welding power source, wire feeding device, etc. are installed separately from the welding machine body, the setting device is used. It is necessary that the output signals of the controller and the signals that can be accepted by the welding machine body, which is the controlled object, completely match. If the levels differ due to differences in rated capacity, etc., a completely misplaced output will occur. For this reason, these large welding devices and welding robots are limited to specific types of welding power sources and wire feeding devices that can be combined with them, and there is almost no freedom in equipment configuration. . SUMMARY OF THE INVENTION The present invention involves first setting the reproduction output setter at a predetermined scale position as a teaching operation, and then manually adjusting the teaching output setter to actually supply a reference signal for output setting to the welding device. When the output value is equal to the setting scale of the output setting device for reproduction, the output value of the output setting device for teaching at this time is taken as the actual output command value, and the output value for reproduction at this time is set as the actual output command value. When performing actual welding, the desired output setting device is used to repeatedly perform the process on the scales of a plurality of output setting devices for reproduction. Select the value,
An arc welding control device is proposed that determines the actual output command value by extracting the output command value corresponding to this selected value directly or by calculation from previously stored data. According to the present invention, by changing various welding conditions and teaching each welding machine to be combined, it is possible to always obtain an output according to the setting scale of the output setting device for reproduction in any case. be. Embodiment FIG. 1 is a connection diagram showing an embodiment of the arc welding control device of the present invention. This figure shows an example in which the present invention is implemented in an apparatus in which the welding current is controlled by the feeding speed of the consumable electrode wire, and the welding voltage is controlled by the output voltage of the welding power source. In the figure, reference numeral 1 denotes a welding power source, and in the embodiment shown in the figure, a power source with substantially constant voltage characteristics whose output voltage is adjustable is used. Reference numeral 2 denotes a motor control section for controlling the feeding speed of the consumable electrode wire 6 (hereinafter simply referred to as wire), and the motor control section 2 controls the feeding speed of the consumable electrode wire 6 (hereinafter simply referred to as wire), and controls the motor 3 according to the welding current setting signal.
control the rotation speed. 4 is a wire feeding roll connected to the electric motor 3, 5 is a workpiece to be welded, and the output of the welding power source 1 is supplied to the wire 6 and the workpiece 5. Reference numeral 7 denotes a welding current detection section, which detects the welding current using a shunt resistor, a DC transformer, etc., and detects the average value of the welding current through a suitable smoothing circuit, low-pass filter, etc. Reference numeral 8 denotes a welding voltage detection section, which detects the voltage between the wire 6 and the workpiece 5 and obtains an averaged output like the current detection section 7. Reference numeral 9 denotes a teaching output setting device which is manually adjusted, and in the case of the embodiment shown in the figure, it consists of a welding current teaching setting device VR ₁ and a welding voltage teaching setting device VR ₂ . Reference numeral 10 denotes a regeneration output setting device, for example, a digital switch such as a thumb loader switch, which includes a welding current regeneration setting device 101 and a welding voltage regeneration setting device 102.
It outputs a digital signal or voltage signal proportional to the set value. 11 manually adjusts the teaching output setter 9 during teaching, and when the outputs obtained by the current detecting section 7 and the voltage detecting section 8 each become equal to the setting value of the reproducing output setting device 10, this is done. an actual output command value storage unit that stores the output signals I _r and E _r of the output setting device 9 for teaching at the time as output command values as a combination with the outputs I _w and E _w of the output setting device 10 for reproduction; is a combination of two adjacent output setting values and output command values among the data stored in the actual output command value storage unit 11, for example, from I _r1 and I _w1 and I _r2 and I _w2 , an intermediate output command is obtained from these combinations. The value is calculated by linear approximation for each appropriate pitch ΔI _w , and the approximate output command value, that is, I _w1 +nΔI _w
13 is an approximate output command value storage section that stores the output data of the approximate output command value calculation section 12 _, and an actual output command value storage section _. The output data of No. 11 and data obtained by calculating data at intermediate positions are both stored. 14 transmits the output value of the teaching output setter 9 as an output command value at the time of teaching to the actual output command value storage unit 11 together with the output of the corresponding output setter 10 for reproduction, and also transmits the output value for reproduction at the time of reproduction. This is a recording and reproducing control unit that reads out a specified output value corresponding to the set value of the device 10 from the approximate output command value storage unit 13. Reference numeral 15 denotes a display section, which inputs the output of the approximate output command value storage section 13 and the outputs of the current detection section 7 and the voltage detection section 8, and displays the output read from the approximate output command value storage section 13 before welding starts. Of these, signals I _w and E _w corresponding to the output of the regeneration output setting device 10 are displayed, and during welding, the outputs I a and E _w of each detection section are displayed.
It includes a switching circuit 151 that switches the input signal to display E _a and a display 152 that displays the result. Reference numeral 16 denotes a mode changeover switch for switching between teaching and regeneration, so that each output of the teaching output setting device 9 is directly supplied to the welding power source 1 and wire feed motor control section 2, which are the welding machine main body, only during teaching. This is for switching the mode of the storage/reproduction control section 14. 17 is a display unit 1 indicating that the teaching output setting device 9 is adjusted and the output current and output voltage match the setting values of the reproducing output setting device 10 during teaching.
When checking in step 5, the combination of the output of the teaching output setter 9 and the output of the playback output setter 10, I _r and
This is a pushbutton switch for inputting a command signal to store I _w , E _r , and E _w in the actual output command value storage section 11. The operation of the embodiment shown in FIG. 1 will be explained with reference to the explanatory diagram in FIG. When the welding machine main body and the control device are initially combined, there is no data in the actual output command value storage section 11, and therefore, of course, no data is stored in the approximate output command value storage section 13, so mode switching is not possible. With the switch 16 on the teaching side (T side), a command value for obtaining a required output value is taught to the device.
2a to 2c show the procedure for teaching the output current with the output voltage fixed. First, as shown in Figure 2a, the output setting device 1 for reproduction is set.
0 current setting device 101 to the minimum output value of the welding machine main body.
Set to I _w1 . Furthermore, the reproduction voltage setter 102 is also set to the minimum output value E _w1 . Test welding is performed in this state, and the current setting device VR ₁ of the teaching output setting device 9 is
and voltage setting device VR ₂ manually to display section 1.
5 displays each setting value of the playback output setting device 10
Adjust E _w1 to match I _w1 . When this adjustment is obtained, press the pushbutton switch 17 and store the set values I _w1 , E _w1 and the command values I _r11 , E _r11 corresponding to those in FIG. 2 a as one set of data in the actual output command value storage. 11. Next, the regeneration output voltage setting device 102 is set to E _w1 as it is, and the regeneration current setting device 101 is set to I _w2 , which corresponds to the position in Fig. 2 a, which approximately corresponds to the maximum output current of the welding machine main body. Change and test weld again. During this test welding, in the same way as before, each setting device VR ₁ and VR ₂ of the teaching output setting device 9 is manually adjusted so that the indications I _a and E _a of the display section 15 are equal to the set values I _w2 and E _w1 , respectively. When the desired output is obtained, press the pushbutton switch 17 to check the output of each setting device at that time (I _w2 , E _w1 , I _r21 , E _r21 )
is stored in the actual output command value storage section 11 as a set of data corresponding to that shown in FIG. 2a. At this time, since the actual output command value storage unit 11 stores data corresponding to the previously stored data, the approximate command value calculation unit 12 stores these two adjacent sets of data (I _w1 ,
From E _w1 , I _r11 , E _r11 ) and (I _w2 , E _w1 , I _r21 , E _r21 ), all the data in the middle part of these are shown in Figure 2a.
Assuming that it _lies on a straight line connecting _the
E Approximate command value storage unit 13 as data for _w1
to be memorized. Of course, the correct actual output command value located between these will vary depending on the output characteristics of the welding machine body, and these are not necessarily directly proportional, but as will be explained later, the more teaching points, the more accurate the actual output command value. Since the value is approximated, there is no need to perform particularly complex curve approximation or function calculations. In addition, the calculation pitch will be determined depending on the capacity of the welding machine body and memory section, but if the output voltage is normally set at intervals of 1V to 2V and the output current is set at intervals of about 2A to 5A, it will be useful to select the actual welding conditions. sufficient accuracy can be guaranteed. Next, set I _w3 and E _w1 (the voltages are the same value in this case) using the reproducing output setting device 10 for the output current and output voltage corresponding to Fig. 2b, and use the same values for teaching as before. The output setting device 9 is operated to obtain command values I _r31 and E _r31 of the teaching output setting device 9 when the actual output matches the setting scale of the reproduction output setting device 10. Data corresponding to this (I _w3 , E _w1 , I _r31 ,
E _r31 ) is stored in the actual output command value storage unit 11, and adjacent intermediate data (I _w1 , E _w1 , I _r11 , E _r11 ) and (I _w3 , E _w1 ,
I _r31 , E _r31 ) and each combination of (I _w3 , E _w1 , I _r31 , E _r31 ) and (I _w2 , E _w1 , I _r21 , E _r21 ) approximate output command values at the same pitch ΔI _w . Arithmetic unit 12
The data in the approximate output command value storage section 13 is updated based on the result of the calculation. As a result, the approximate output command value storage section 13 stores data on the polygonal line shown by the solid line in FIG. 2(b). If the same operation is repeated for other output current setting values _Iw , the output voltage setting value becomes _Ew1 , and the detailed relationship between the output current setting value _Iw and the output current command value _Ir is as shown in Figure 2c. Obtainable. Furthermore, if the above operation is repeated for different output voltage setting values E _w , each output voltage setting value
Combinations of output command values E _r and I _r corresponding to the combinations of E _w and output current setting value I _w are obtained as shown in Table 1.

【table】

Claims (1)

[Claims] 1. An arc welding control device that feeds back the output to match the set value, including a reproduction output setter for setting a desired output value, and a manual output setting device for adjusting the output during teaching. A teaching output setting device, a welding machine body whose output is determined according to the setting signal, and a reproduction output setting device whose output is set in advance by changing the output of the teaching output setting device. an actual output specified value storage section that stores the output of the teaching output setter when the output setting device matches the set value as an output specified value in combination with the output of the reproduction output setting device according to a command; When an output command value is added, it is compared with other previously stored actual output command values, and another actual output command value that is adjacent to the new actual output command value is selected, and a predetermined distance between the two is selected. an approximate output command value calculation unit that calculates approximate output command values for each division pitch by performing approximate calculations on divided pitches; an approximate output command value storage unit that stores the calculation results of the calculation unit together with the actual output command values; At times, the combination of the output of the teaching output setter and the corresponding output of the reproduction output setter is transmitted to the actual output specified value storage section, and at the time of reproduction, the set value is received from the reproduction output setter. an arc welding control device, comprising: a storage and reproducing control section that reads a corresponding output specified value from the approximate output command value storage section and supplies it to the welding machine main body as a command value. 2. In an arc welding control device that feeds back the output to match the set value, there is an output setting device for reproduction to set the desired output value, and a teaching output setting to manually adjust the output during teaching. When the output of the welding machine body, whose output is determined according to the setting signal, and the teaching output setting device are changed and the output of the welding machine body matches the preset setting value of the regeneration output setting device. an output command value storage section that stores the output of the teaching output setting device as an output command value in combination with the reproduction output setting device and the output, and when a new output command value is added to the output command value storage section; is compared with other previously stored output command values, selects another output command value that is adjacent to the new output command value, and calculates an approximation between the two at a predetermined division pitch for each division pitch. an approximate output command value calculation unit that calculates an approximate output command value and writes and corrects the calculation result in the output command value storage unit as an approximate output command value; and an output of the teaching output setter at the time of teaching and a corresponding reproduction transmitting the combination with the output of the output setting device for reproduction to the output command value storage section, and upon reproducing, receiving the setting value from the output setting device for reproduction, reading out the corresponding output command value from the output command value storage section; An arc welding control device equipped with a memory and replay control section that supplies command values to the welding machine main body. 3 In an arc welding control device that feeds back the output to match the set value, there is an output setting device for reproduction to set the desired output value, and a teaching output setting to manually adjust the output during teaching. When the output of the welding machine body, whose output is determined according to the setting signal, and the teaching output setting device are changed and the output of the welding machine body matches the preset setting value of the regeneration output setting device. an output command value storage unit that stores the output of the output setting device for teaching as an output command value in combination with the output of the output setting device for reproduction according to a command; The output command value corresponding to the input signal is calculated by an approximation calculation from the output command values on both sides adjacent to the input signal by comparing it with other output command values stored in the output command value storage unit. an approximate output command value calculation unit that supplies the output command value to the welding machine main body; and transmits a combination of the output of the teaching output setter and the output of the reproduction output setter to the output command value storage unit during teaching. and a storage/reproduction control section which receives the set value from the reproduction output setter during reproduction, reads out output command values on both sides adjacent to the input signal from the output command value storage section, and supplies them to the approximate command value calculation section; Arc welding control device equipped with