JPS6167571A - Welding tracing control device - Google Patents

Abstract

PURPOSE:To improve the profile accuracy by counting the time of an arc generation and a short-circuit from a binary-coding signal of a welding voltage, inputting it to a band pass filter, and correcting dislocation based on a synchronously rectified integral value of its output. CONSTITUTION:A comparator 52 inputs a welding voltage 51, and outputs a signal 53 of '1' and '0' in the course of an arc generation and a short-circuit, respectively. A rise differentiating circuit 56 differentiates a rise of the signal 53, and outputs a shift clock 57. A logical circuit 60 executes an integration of one period and a half period of weaving by integrators 72, 77 by its outputs 47', 49', and counting of the time. When executing the welding by weaving, a digital band filter 66 extracts a sample piece number component in a half period of weaving, rectifies synchronously its output signal, and integrates it for one period or a half period by the integrator 72. Dislocation is corrected based on this integral value, therefore, the profile accuracy is improved.

Description

[Detailed description of the invention] [Industrial application field] The great invention is welding welding 19 imitation l/) M
Regarding a control device.

[Conventional technology]

Conventionally, various types of welding tracing control systems have been implemented as t/'f± devices. "Utility Model Publication No. 55-130254 and "Special Publication No. 57-2428J obtain a positional deviation correction signal from a desired weld line by detecting and comparing the welding currents flowing at both ends of the weaving. However, This method contains a lot of disturbance information (wire feeding unevenness, short-circuit development, power supply ripple, etc.) other than the current force level and information, and the fluctuation of the current itself is large and the arc force is stable. 9! +, ), short arc state and globular state have the disadvantage that position detection accuracy decreases in small current states, so it is applied exclusively to spray arc states with large current values. It is something.

[Special Publication Publication No. 57-2428J smoothed the pulsation of welding current by using a cylindrical filter.
Even if the time constant of the low-pass filter is increased to suppress the pulsation to a small value, the position information and disturbance information contained in the welding current cannot be separated, and in the small current range,
It still has the drawbacks mentioned above.

[Unexamined Japanese Patent Publication No. 52-9857j attempts to improve position detection accuracy by comparing the integrated value of the current at both ends of the weaving several times and the average value. This method has the disadvantage that the output of the deviation correction signal is delayed and the tracking accuracy of the scanning control is reduced. If the welding speed is reduced in order to reduce the follow-up delay by shortening the length of the weld line progressing during this wasted time, a problem arises in that production efficiency decreases. For this reason, if the welding speed is left unchanged and the weaving frequency is increased, the weaving period becomes shorter, and even if the welding current, which contains a lot of disturbance information, is integrated and averaged over that period, the integral interval itself is short. Therefore, the removal rate of disturbance information per one integration decreases. If the number of averaging times is increased in proportion to the weaving frequency, it is possible to compensate for the reduction in the rejection rate of disturbance information, but this will result in a detection delay and will not compensate for the tracking delay.Therefore, increasing the weaving frequency However, it cannot be expected to improve the position and detection accuracy.

Furthermore, all of the above cited documents involve weaving the welding torch itself, and the weaving frequency is at most several H1, so it is not possible to cover a small current range by increasing the weaving frequency.

On the other hand, ``Japanese Patent Application Laid-Open No. 52-15457J proposes a method in which the arc itself is weaved using a magnetic field instead of weaving the welding torch.This method does not involve mechanical weaving, so it is possible to achieve a high weaving frequency. Since the welding torch requires a large winding to generate a magnetic field, it has the drawbacks of poor accessibility to the welding line and weight.Therefore, this method is not suitable for some specialized machines. It can only be used for robots, and is not suitable for use in robots.

[Problem that the invention seeks to solve]

An object of the present invention is to provide a highly accurate welding tracing control device that is not affected by the magnitude or waveform of welding current or the short-circuit transition state of the arc even when the weaving center and weld line are deviated.

[Means for solving problems]

First, the present invention will be explained in detail.

FIG. 8 is a diagram showing the positional relationship between the welding torch and a desired welding line, in which (a) is a downward cross-sectional view, and FIG. 8(b) is a water cross-sectional view.

1 is the base material to be welded, 2 is the desired welding line, 3 is the direction perpendicular to the welding line 2, 4 is the power supply lip, 5 is the consumable electrode, and 6 is the weaving direction within the cross section perpendicular to the direction of the welding line 2. and positional deviation correction direction (left and right), 7 is the torch height correction direction (up and down) perpendicular to the weaving direction 6, 8 is the desired tip-base metal distance, and 9 is from the desired welding line 2 at the weaving center of the torch. The positional deviation amount, lO, is the deviation amount in the torch height direction from the desired tip-to-base material distance.

From the welding parameters that change according to the distance between the chiabo base metals caused by weaving the torch and this search movement,
Misalignment in the weaving direction as shown in a) and (b) 9. The amount of deviation 10 in the torch height direction is detected, and these are O
Arc and tracing control guide the torch so that

FIG. 9 is a diagram illustrating the weaving motion and the corresponding variation in the distance between the chia and the base material.

(a) is the ■ groove, (b) is the V groove seen from the arrow direction shown in (a), 12 is the weaving waveform when the weaving center is along the welding line 2, 13 is weaving only by the storm of the weaving amplitude Weaving waveform when the center is misaligned, 14 is a weaving waveform when only the intestine of the ping amplitude is misaligned, 15 is a weaving waveform when the center is misaligned in the opposite direction to 14, (C) is the waveform of the weaving motion, (d) to (g) are the distances between the two parts and the base metal when the weaving center is +2, 13, 14, and 15, respectively. (e), (f) As shown, the weaving frequency component of λ increases according to the positional shift. As shown in (d), when the weaving center coincides with the welding line 2, the length becomes the weaving frequency 2 f3. Furthermore, as shown in (f) and (g), when the direction of positional shift changes, the phase of the sentences differs by 180°.

From the above, explore ig! It can be seen that positional deviation information can be obtained by extracting welding parameters that indicate the frequency components of the weaving motion.

FIG. 10 is a diagram showing the short-circuit transition type y8. Figure (a)
, 16 is the welding power source, 17 is the welding power source IB 2
Next side positive cable, 18 is secondary side negative cable,
+9 is a wire extension. The figure (b) is 2
Next positive cable 17 and secondary negative cable 18
20 shows the arc generation time (hereinafter referred to as arc time), and 21 shows the short circuit time (
(hereinafter referred to as short circuit time rs). As is well known,
In the short-circuit transition mode, the process of arc generation (melting energy generation -> between wire extensions 19 &) - short A8 (melting energy generation due to short circuit current) - electrode fusing - arc generation is repeated.

Figures 11(a) and (b) show the power spectrum of the live-beam interlock and the arc time T^ when the positional deviations shown in Figures 8 and 9 are removed in the short-circuit transition mode shown in Figure 10. It is a figure showing each actual measured value. These are 1
This was done to see the correlation between the arc time ^ sequence of actual welding results when the position is misaligned and the weaving movement (single harmonic) sequence when the arc time is constant, and there is a strong correlation between them. This proves that the arc time is one of the welding parameters that can serve as a source of positional deviation information as explained in FIG. The horizontal axis is a numerical value obtained by normalizing the reciprocal of the frequency, and the smaller the numerical value, the higher the frequency.The high frequency component of the arc time yA becomes a noise component for the position information. Therefore, to extract the weaving frequency component, a /<nd pass filter is required.

Figure 12 (a) is the same welding voltage waveform as Figure 10 (b), and Figure 12 ('b) is the time count value at the time of data sampling of the arc time ＾.
．． Data 3. Data 4) fi (indicates 4 guns A).

What should be noted here is that both the horizontal and vertical axes in the diagram (b) represent time. In other words, unlike sampling at fixed time intervals, this is variable sampling time series data where when a large value is input, the sampling interval is expanded, and when a small value is input, the sampling interval is shortened. .

FIG. 13(a) is a diagram showing the basic configuration of a comb-shaped digital filter, in which a multiple bandpass filter Z having 12/2R zero points from O to the Nyquist rate and an integrator Z having 972 poles in the subsequent stage are used. A finite response is obtained by overlapping the zero point and the pole. The basic block of R, P is written as C; OM (R, P:] in Figure 13 (b
) is a block diagram of a digital bandpass filter that extracts a component corresponding to a variable sampling frequency component.

The passband of this bandpass filter is not the frequency, but
The number of samples. In other words, it is a digital band pass filter that only passes time series data of the sampling number corresponding to the weaving half cycle. Once the welding conditions are determined, the analysis of the variable sampling time series data T is almost decided, and the regression equation of TA with those conditions as parameters is determined experimentally in advance, and then the number of samples for each weaving half cycle is estimated. Or, if the regression formula has not been determined based on the welding conditions, sample the input data for several points at the same time as welding starts, and then estimate the regression formula.

Similarly, the passage constant of the digital filter is automatically set by estimating the number of TA samples.

FIG. 14 is an example of a weighting function that constitutes this digital filter. By geometrically determining a rectangle or a triangle in this example, the gain can be made constant so that the area is constant. Even with such a weighting function, the amount of attenuation in the stop band can be reduced by connecting several filters directly to the filter.
About 4 seconds is sufficient. In fact, this level of volume reduction is sufficient. Preliminary note: Use lFT, etc. to find out how many samples pass through the width and find the coefficient.

The filter constant for any number of passing samples (passing characteristic) can be easily determined by proportional calculation.

Based on the above principle, the present invention counts the arc time or short circuit time at the end of the arc or at the end of the short circuit, and calculates the number of samples per hour count value characteristic instead of the frequency-width characteristic of the usual filter. Manually calculate the arc time or short circuit time count value that occurs intermittently in a digital band pass filter having a digital band pass filter, rectify the output of the digital band pass filter in synchronization with the weaving half-cycle signal, During the single weaving period, the positional deviation correction direction is determined according to the polarity of the integral value during (±1 period), and the positional deviation of the torch with respect to the welding line is corrected by servo-controlling the left and right servo motors so that the integral value becomes zero. Further, one aspect of the present invention is to extract only the arc'it flow from the welding current using the binarized signal at the same time as this positional deviation correction control, and to apply this arc current to the welding current during one cycle or half of the lie-pink cycle. At the same time as the arc period is integrated, the calculated value of the arc generation time during that period is calculated 17, thereby calculating the average value of the executed arc current, and the height correction control in the direction of the torch is performed so that the calculated value follows the desired set value. You can also do it.

〔Example〕

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 3 is a schematic diagram of a welding apparatus equipped with a control device and a workpiece to be welded (water + filler) according to an embodiment of the present invention.

This welding device includes a power supply tip 21, a consumable electrode 22, a welding torch 23, a motor 32 for correcting positional deviation in the operating direction, and a motor 33 for correcting positional deviation in the height direction. Weaving device 31 including a weaving motor. Welding machine 34° power supply cable 37
, a welding current detector (for example, a shunt) 35, a welding current detector 35 detecting the welding xi, an arc voltage 51 from the welding machine 34, and a weaving synchronization signal 46 from the weaving device 31. and a welding tracing control device 40 that controls the height direction positional deviation correction motor 33 to weld workpieces 38 and 39 to be welded.

The arrow al indicates the axial direction of the welding torch 23, and the arrow a2 indicates a direction substantially perpendicular to the axial direction of the welding torch 23. In the following explanation, they will be referred to as "height direction" and "horizontal direction," respectively.
It is called. In the case of V-groove 7-ku, the definitions of "flavor direction" and "horizontal direction" are the same. The expression is the distance between the chip and the base metal. In MAG welding, in order to guarantee welding quality, it is necessary to control the welding current to be constant, that is, to keep the distance fIk between the two parts and the base metal constant. Note that, in FIG. 1, the traveling shaft motor that moves the welding torch 23 along the welding line is not shown.

FIG. 2(a) is a block diagram of the weaving device 31,
Weaving frequency/amplitude setting device 41, weaving motor drive circuit 42, weaving motor 43, weaving center position detector directly connected to weaving motor 43 to detect weaving center position, weaving operation I as shown in FIG. 2(b). It consists of a toss waveform shaping circuit 45.

FIG. 1 is a block diagram of a welding profile control device 40.

The comparator 52 inputs the welding voltage 51 and sets it to 1 during arc generation.
'', and outputs a signal 53 of ``O'' during short circuit. Ant circuit 55 outputs clock signal 54 when signal 53 indicates that an arc is occurring.
A rising differentiation circuit 56, which passes through the signal, differentiates the rising edge of the signal 53 indicating that an arc is occurring, and outputs a shift clock 57 indicating the end point of arc generation. The shift register 58 outputs a weaving delayed synchronization signal 46' which is obtained by delaying the weaving synchronization signal 46 by the time required to shift the number of vias in the shift register 57. The logic circuit 60 inputs the weaving d synchronization signal 46' and outputs control signals 47', 48', 49' as shown in FIG.
, 50' is output. The control signals 47' and 49' are used by integrators 72 and 77, which will be described later, to perform integration of one weaving period and half period, and time counting, respectively. Control signals 48' and 50' are used for sample commands of sample and hold circuits 73 and 80, which will be described later, to hold the sample values for one weaving cycle and half a weaving cycle, respectively. The r-movement switch 1 performs integration for each weaving cycle and a timer counter control signal 47', integration for each weaving half cycle and switching the timer counter control signal 49', and a control signal 48' for each weaving cycle and a weaving half cycle. Control signal 50 per cycle
' are performed in conjunction with each other and output as control signals 62.83. The delay circuit 64 delays the soft clock 57 of the falling differentiation circuit 5B by a predetermined time. The timer count 65 counts the clock (arc time TA) output from the ant circuit 55 and is reset by the shift clock 57 delayed by the delay time of the delay circuit 64.

The digital band pass filter 66 is a digital band pass filter as explained in FIG.
The built-in shift register is shifted every 57 times. The sign inversion circuit 87 outputs a numerical value with the sign of the output numerical data of the digital bandpass filter 66 inverted. On the 6th day of the electronic switch, the weaving delay synchronization signal 46' is -1~
When the value is O'', the output value of the digital band pass filter 86 is selected, and when the value is O'', the output value of the sign inversion circuit 67 is selected. That is, the sign inverting circuit 67, the electronic switch 68, and the digital weaving J! ! It constitutes a digital synchronous rectifier 68' which rectifies using the U synchronous signal 46'. The latch circuit 71 latches and integrates the output of the adder 69 every clock 70 when the control signal 62 is ``1'', and is reset when it is ``o''.The adder 68 combines the output of the synchronous rectifier 68' and the latch circuit. 71. That is, the adder 69 and the latch circuit 71 are added together.
constitutes a digital integrator 72 that integrates the output of the digital synchronous rectifier 68' during one weaving period and one weaving period. The digital sample and hold circuit 73 latches the output of the digital integrator 72 when the control signal 63 is ``O'', and holds the latched value when the control signal 63 is 1'', thereby performing digital integration after one weaving period or half a period. The output of the device 72 is sampled and held. A comparator with hysteresis 74 compares the output of the digital sample and hold circuit 73 with O(V) within or above the minute dead zone d.An amplifier 75 amplifies the welding current detected by the welding current detector 35. The analog switch 76 is the comparator 52
The effective arc current is extracted by passing the output of the amplifier 75 when the signal 53 output from the integrator is between ``1'' (during an arc) and reset to zero when it is -0'' (during a short circuit).Integrator 77 integrates the output of the analog switch and chia 6 when the control signal 62 is 1-, and is reset when the control signal 62 is 0" to obtain the integrated value of the arc current for one cycle or half cycle of weaving. Timer count 7
8 counts and integrates the arc time TA from the tally clock 54 output from the AND circuit 55 when the control signal 62 is '1'', and is reset when O~, thereby weaving 1.
Find the integral value of the arc time for a period or half period. The average value calculation circuit 79 converts the output of the integrator 77 into the timer counter 7.
By dividing by the output of 8, the average value of the executed arc current for one cycle or half cycle of weaving is calculated. The analog sample hold circuit 80 receives the control signal 63'l
By tracking the output of the average value calculation circuit 79 when ``'' and holding that value when ``0~'', the average arc 'Nf & value after one weaving cycle or half a cycle is sampled and held.Comparator with hysteresis Reference numeral 82 compares the output of the analog sample and hold circuit 80 with the set value 81 of the desired effective arc current within or above the small dead zone d.

Next, the operation of this embodiment will be explained. The component corresponding to the weaving frequency of the sample time series data, that is,
The sample number component within the weaving half cycle is extracted by the digital bandpass filter 66, and the DC signal output from the filter 7 is synchronously rectified by the digital synchronous rectifier 68' and the weaving delay synchronous signal 46', and the output DC signal is The digital integrator 72 and the control signal 82 integrate the weaving for one period or half period, and the output is sampled and held for each weaving period or half period by the digital sample and hold circuit 73 and the control signal 63. The weaving frequency component of the chip-base metal pressure # (in this case, arc time ＾) due to the direction of deviation explained in (in this case, the sample number component of the arc time during the weaving half cycle)
The phase reversal phenomenon is equivalent to the polarity reversal when the component is synchronously rectified with a C-hing synchronizing signal, so the direction can be determined by the output polarity of this sample hold. The positional deviation can be corrected by controlling the positional deviation correction motor 32.

The reason why the weaving synchronization signal 46 is delayed as 46' is due to the number of shifts in the digital bandpass filter 66 of the OT variable pull time series data, the number of samples, and the f-ping half due to disturbance noise. The purpose is to correct the phase disturbance of the I^sample PJ component within the cycle. Schiffhill register for this phase adjustment. The number of evening bits can be set by manual switching of pre-wiring (not shown).

The digital band is in a state where it is assumed that the number of bits of the shift register 58, that is, the phase adjustment, is properly adjusted, and that the sample number component of TA within a single weaving period is the same as the weaving frequency component of the distance between the chip and the base material. When the attenuation rate of the pass filter 66 is set high, the relationship between the amount of positional deviation and the output waveform of the band pass filter 66 becomes as shown in FIGS. 9(d) to (g). At that time, assuming that the control signals 47' and 48' are selected by the manual switch 61, the digital synchronous rectifier 68' and the digital integrator 72
．． Each output of the digital sample and hold circuit 73 is shown in FIG. 5, and is shown as an analog value for convenience of explanation. 17
2~175°176~179. 180~183 are digital synchronization at Figure 9(d)~(g) respectively? ! ! sink 6
The sample-and-hold output increases in proportion to the magnitude of the zero position deviation, which is the output of 8', the output of the digital integrator 72, and the output of the digital sample-and-hold circuit 73, and the polarity of the sample-and-hold output differs depending on the direction of the position deviation. I understand. The method of determining the direction of deviation based on the output polarity of the digital synchronous rectifier 68' may result in an incorrect direction of deviation f1. Digital integrator 7 is used to prevent misjudgment.
2 and a digital sample hold circuit 73 are provided.

Figure 5 shows the output signal under the above-mentioned preconditions,
In reality, due to Senna response constraints, a bandpass filter 6
The attenuation rate of B cannot be made extremely large. Therefore, the output waveform of the digital bandpass filter 68 is distorted due to the influence of disturbance noise in the number of samples near the center passband of the digital filter. Even if the rectification is performed to the greatest common divisor, depending on the amplitude of the distorted wave, the noise output will be included in the synchronous rectification output, and the waveform 173 in Figure 5 is actually analog in Figure 6 (similar to Figure 5). The result is an irregular waveform as shown in (expressed). but.

As shown in the figure, disturbance noise can be removed by integrating one cycle of weaving, and accurate positional deviation detection can be performed. However, even in the case of this embodiment in which the amount of positional deviation is assumed to be constant, the polarity of the sample hold output is constant as shown in the figure, and the output value fluctuates. Compared to servo control, the comparator 7 with hysteresis controls only the polarity, that is, the direction of positional deviation.
It is preferable to perform on/off servo control in which the correction operation is performed once per sample in the direction of correcting the positional deviation after the sample by a predetermined position correction amount based on the on/off command.

Next, the operation of height control will be explained.

FIG. 7 shows the welding voltage 51 and comparator 5 explained in FIG.
53. which is the output of 2. Welding 1J which is the output of amplifier 75
! , current and analog switch 7G output (arc\L flow)
Diagram showing the relationship (when sections T, T2, and r3 are short-circuited)
It is. The execution arc current 200 excluding the short k11 current is integrated by the integrator 77 for one weaving cycle or half cycle, and at the same time the timer counter 78 counts the clock passed through the AND circuit 55 for one weaving cycle or half weaving cycle. The cumulative value of the actual arc occurrence time is calculated by Ni. An average value is calculated for each weaving cycle or half cycle based on the cumulative value of the execution arc occurrence time and the output of the integrator 77, and the average value is sampled and held by the analog sample and hold circuit 80. By comparing the execution arc electric value for one cycle or half cycle with a predetermined set value 81 using a comparator 82 with hysteresis, the taste direction correction motor 33 in the torch height direction explained in FIG. 3 is controlled (set value When the chip is smaller than 81, the chip is moved toward the base material, and when it is larger, the chip is controlled in a direction away from the base material.By doing so, the average distance between the two chips and the base material can be kept constant. In this case, like the positional deviation correction control, whether the weaving half-cycle control is one-cycle control or not is selected by the manual spin control 1. Regarding this correction in the height direction, on/off servo control that includes a hysteresis comparator 82 and makes corrections once per sample is more preferable than linear servo control.

As is clear from the above explanation, it has become possible to accurately extract minute positional deviation information from arc time information even in a short arc process in which arc generation and short circuits are repeated. In addition, by servo-controlling the positional deviation correction data and height correction data using this positional deviation detection sensor signal, arc tracing control in the short arc process has become possible. Since the servo is sampled and controlled every weaving cycle or half cycle, responsiveness is good, and the distance between the base metals, that is, the arc current, is controlled at a constant level by the executed arc, improving welding workability and welding quality. The stability has been improved.

Although the above examples were carried out using a weaving motor, a position/misalignment correction motor, and a height correction motor, the robot drive shaft of the industrial robot can be used without attaching these dedicated motors to the robot wrist. Since it is easy to use the soft weaving function as a synthetic movement of the robot drive shaft, the position correction machine ff, and the height correction function using the robot drive shaft, the present invention also includes a system in which all movements are performed by robot drive shaft control. It is natural that this happens. Furthermore, although positional deviation detection has been described using a digital circuit, analog processing may be performed entirely.Furthermore, a method may be considered in which positional deviation correction is performed using short circuit time information instead of using arc time information. In that case, change the falling differentiation circuit 56 to a rising differentiation circuit, cut off the input from the output of the AND circuit 55 to the timer counter 65, and install a new comparator.
This can be easily realized by providing an AND circuit and inputting a timer clock indicating the short circuit time to the timer counter 65.

〔Effect of the invention〕

As explained above, the welding profile control device of the present invention has the following effects: (1) From the arc time or short circuit time containing miscellaneous information, the sample number component related to the positional deviation between the weaving center and the weld line Since it only detects
It is not affected by the pulsation of the current waveform determined by the magnitude of the welding current and the arc transition form by the components of the shielding gas, and enables highly accurate position and deviation detection in short arcs and globular arcs as well as in spray arcs. (2) Instead of keeping the average arc current including short circuit current constant,
Since the height in the torch direction is controlled to keep the effective arc current constant, high-quality welding is possible regardless of the transition state of the arc. (3) Position and misalignment correction signals (left and right signals ), a height correction signal (up/down signal) is generated, reducing sensor dead time and improving tracing accuracy.
There is no need to reduce the welding speed, so there is no drop in production efficiency due to tracing control. (4) In proportion to the weaving frequency, sensor response can be improved without compromising positional deviation detection accuracy (sensor dead time small), (5)
This is a method in which the torch itself is weaved, and there is nothing added that would interfere with welding, so it has excellent accessibility to the workpiece and reliability under adverse environments such as heat, heat, and arc light. 1st prize.

[Brief explanation of the drawing]

1 is a block diagram of a welding profile control device according to an embodiment of the present invention, FIG. 2 is a block diagram of the weaving device 31 of FIG. 3 and a waveform diagram of a weaving synchronization signal, and FIG.
The figure is a block diagram of a welding apparatus equipped with the welding profile control device 40 of FIG. 1, and FIG. 4 is a control signal 47' output from the logic circuit 60 of FIG. 48', 49', 50', a weaving delay synchronization signal 46', and a weaving synchronization signal 46; FIG. FIG. 5 shows that the attenuation rate of the digital bandpass filter 68 is increased, and the phase relationship between the weaving motion and the tip-to-base distance is as shown in FIG. 9, and the digital synchronous rectifier 68' and digital integral FIG. 6 is a diagram showing the waveforms of the outputs of the circuit 72 and the digital sample hold circuit 73.
FIG. 7 is a diagram showing the waveforms of the synchronous rectification output, integrator output, and sample hold output after phase adjustment when the positional deviation is relatively large. Output 53 of comparator 52. Figure 8 shows the waveforms of the welding current and arc current, Figure 8 shows the positional relationship between the welding torch and the desired weld line, and Figure 9 explains the weaving motion and the corresponding variation in the tip-base metal distance. Figure 10 is a diagram showing the short-circuit transition mode, Figure 1
Figure 1 (a,) and (b) are diagrams showing the measured values of the power spectrum of weaving interlocking and arc time, respectively.
Figure 2 is a diagram showing the relationship between the welding voltage waveform and the data sample value of the 7-time period TA, Figure 13 is a block diagram of the basic configuration of the comb-shaped digital filter and the digital bandpass filter, and Figure 14 is the diagram of the digital bandpass filter. It is a figure which shows the example of the weighting function comprised. 46: Weaving synchronization signal, 46': Weaving delay synchronization signal, 47', 48', 49', 50'
: Control l@ number, 51: Welding voltage 52/Comparator. 54: Clock, 55: AND circuit, 56: Downward differential circuit, 58: Shift register, 60:
Logic circuit, 61: Manual switch, 64: Delay circuit, 65
．． 78: timer counter, 86: digital band pass filter, 67: sign inversion circuit, 68 two-electronic switch, 69:
Adder, 71: Latch circuit, 73: Digital sample hold circuit, 74.82 Comparator with nihysteresis, 75 Two amplifiers, 76: Analog switch. 77: Integrator, 79: Average value calculation circuit, 80
:Analog sample halt circuit. (a) Figure 4 Figure 5 Figure 6 (a) (b) Figure 8 ↓ (a) Figure 11 (b) Figure 10 Figure 12

Claims (1)

[Claims] A circuit that counts the arc generation time or short circuit time using a binary signal of the welding voltage in a welding method that automatically follows the groove while weaving the welding torch under the short arc process where arc generation and short circuit are repeated. a bandpass filter that passes only a statistical estimate of the number of occurrences of the arc occurrence time or the short circuit time within a weaving half cycle, that is, a statistical estimate of the number of samples; and a weaving synchronization signal whose phase can be adjusted for the output of this bandpass filter. A synchronous rectifier that rectifies in synchronization with
Welding characterized by comprising an integrator that integrates, and a control circuit that determines a positional deviation correction direction according to the polarity of an integral value of this integrator and performs positional deviation correction control so that this integral value becomes zero. Copying control device.