JPH0570553B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a butt welding device for steel plates, and in particular,
The present invention relates to a tracing device that causes a welding torch to trace a butt position in butt welding of steel plates.

[Conventional technology]

For example, in a continuous processing line for thin steel plates, various welding methods are used to connect the rear end of the leading strip and the tip of the trailing strip for continuous sheet threading. Currently, there is no satisfactory welding method due to the problems of butting the plates and the welding speed. However, when it comes to welding thick plates, for example, welding journals
As shown in the December 1959 issue, pages 1182-1191, TIG arc welding is mainly used.

If the plate thickness is around 0.35mm, it is possible to weld using the TIG arc welding method, but if the plate is thin, the welding current will be as low as 10A, so the arc will be unstable and the power supply characteristics will be greatly affected. This causes heat input fluctuations during welding, resulting in unstable bead formation and the problem of welding defects. Energy beam welding such as laser welding enables butt welding of thin plates, but even in this case, the butt gap must be made as small as possible and the beam must be accurately positioned at the butt portion.

In any case, in butt welding, it is necessary to keep the butt gap within a predetermined range and to accurately position the welding head relative to the butt portion.

Conventionally, two sets of photoelectric conversion cameras are integrated with a welding torch, one set of cameras detects the position of the butt part before welding, and the other set of cameras detects the position of the welding spot. A copy welding method has been proposed in which the angle of the laser deflection plate is corrected so that the welding spot is located at the abutting portion, and the laser beam follows the abutting portion (Japanese Patent Application Laid-Open No. 100948/1983).

[Problem that the invention seeks to solve]

For example, a television camera or a linear CCD is used as a camera to photograph the butt portion of the steel plates. In either case, reflected light from the steel plate is converted into an electrical signal at least in one dimension (straight line) in a direction perpendicular to the butt line. From the electronic scanning position from the base point, it can be determined which position on the steel plate the electrical signal at each time corresponds to. However, in laser welding, for example, the butt gap is extremely narrow, so there is little difference in the amount of reflected light between the continuous part (steel plate surface) and the butt part (end contact part) on the steel plate.
In the video signal obtained from a CCD, the signal level difference between the bright part (surface) and the dark part (butt part) of the steel plate is small, and the video signal contains a lot of noise due to optical noise and electrical noise. There is a problem that signal processing for identifying the dark area (matching area) is more complicated than the signal, and it is difficult to accurately identify the area. In particular, in the first set of cameras that detects the position of the butt part before welding during laser welding, the light emitted from the welding spot enters the first set of cameras, making it difficult to detect the position of the butt part. Even if light is shielded between the welding spot detected by the second set of cameras and the abutting part of the field of view photographed by the first camera, the light from the welding spot passes through the abutment gap and the field of view photographed by the first camera abuts. This brightens the abutting area that should be detected as a dark area. In addition, since the welding spot emits light from the laser beam in a wider area than the butt gap, the second
It is also not possible to accurately detect the position of the laser beam using a set of cameras. Particularly in laser beam welding, since the butt gap is extremely narrow, position detection errors by the first and second sets of cameras have a large effect, resulting in welding position deviation. Further, at the welding start end, the position of the laser beam cannot be detected by the second set of cameras on the steel plate, resulting in a positional deviation of the laser beam irradiation.

In laser beam butt welding, it is necessary not only to make the laser beam follow the butt line, but also to accurately set the butt gap before welding. Therefore, it is preferable to detect the butt gap for the entire weld line before welding, and to reset the gap if the gap setting is incorrect. With the above-mentioned conventional technology, it would be possible to scan the butt line before welding and detect the gap at each position of the butt part, but it is possible to detect the gap at each position of the butt part by scanning the butt line before welding. In this case, the light incident conditions for the camera are different, and it seems necessary to perform mechanical or electrical correction accordingly. Such correction reduces workability and requires the addition of mechanical or electrical correction elements.

The first object of the present invention is to provide a tracing device that can trace a welding torch from a welding start end to an abutting part, and can accurately position the welding torch with respect to an abutment line during welding, and includes conversion of imaging conditions, etc. A second object of the present invention is to provide a copying device capable of adaptively detecting a gap in an abutting portion before starting welding without requiring additional elements or additional work.

[Means for solving problems]

In order to achieve the above object, in the present invention,
A photographing means for converting light from the abutting portion of the steel plates into an electric signal and a welding torch for welding the abutting portion are coupled to a first base, and the first base is driven in the x direction intersecting the butt line. In addition to having an x-axis drive means,
The x-axis driving means is coupled to the second base and the second
The base is configured to be driven in the y direction by a y-axis drive means. As a result, the photographing camera and the welding torch are driven together in two dimensions in the y direction along the butt line and the x direction intersecting it.

The present invention further includes a second base movement synchronizing pulse generating means that generates one electric pulse every time the second base moves a predetermined distance in the y direction, and corresponds to the forward and reverse movement directions of the second base. and counting means for adding and subtracting the electrical pulses, thereby tracking the y position of the second base, that is, the position in the direction of the butt line between the photographing camera and the welding torch.

In addition to these, in the present invention, the photographing means further includes:
The detection means detects the x-direction position of the abutting part of the steel plate by processing the signal obtained by imaging, and detects the x-direction position of the abutting part, and the detecting means detects the x-direction position of the abutting part. a memory means for storing the detected position data in association with the count data of the counting means; a reading means for reading position data corresponding to the count data of the counting means from the memory means when the second base is moved in the opposite direction; A position control means is provided for positioning the welding torch above the position indicated by the position data by energizing the x-axis drive means based on the read position data.

According to this, if the butt line is from Ys to Ye, the second base is driven in the y direction from before Ys (root side of the butt line) to beyond Ye (butt part position detection drive) While doing so, the x-direction position of the abutting portion at each position in the y-direction is detected and stored in the memory means in association with the y-direction position. Next, while the second base is being driven back (welding tracing drive) from the other side of Ye to the front of Ys, the x-direction position of the abutting portion at each position in the y-direction is read out from the memory means, and this readout is Based on the data, the first base is driven in the x direction to align the welding torch over the abutment. That is, x-position detection and copy welding are performed at each position in the y direction of the butt portion in one reciprocation along the butt line.

Therefore, abutment position detection (x position detection)
In this case, there is less optical noise at the abutting part, position detection is accurate, and in copy welding, welding is performed by accurately aligning the welding torch with the abutting part from the starting end Ye of the abutting part. The y-direction position is constantly tracked by a reversible counting means, and the momentary y-position is grasped by one counting means in both forward driving and backward driving in the y-direction. Position calculation processing is virtually unnecessary. Since the abutment position x of each abutment line position y during the forward drive is held in the memory means,
It is possible to detect the quality of the gap at the abutting portion during the forward drive, and it is easy to detect the quality of the gap across the entire width at the end of the forward drive, and if the gap is poor at the end of the forward drive, the butt is repeated Correction work such as redoing can be easily performed.

In a preferred embodiment of the present invention, the detection means for detecting the position in the x direction moves the photographing means in the y direction along the abutting line, and detects a plurality of photographic signals at different positions along the abutting line. Add up the data at the same electronic scanning position, obtain electronic scanning position data from the base point in the photographing camera by counting electronic scanning synchronization pulses, and match the count value corresponding to the signal at the level corresponding to the darkest part among the added signals. It shall be obtained as the position of the department. In addition, electronic scanning position data from the base point in the photographing camera is obtained by counting electronic scanning synchronization pulses, and the count values at one end and the other end of the dark part of the count value corresponding to the signal at the level corresponding to the dark part in the addition signal. Let us obtain the difference between them as the butt gap.

According to this, since the optical noise and the electrical noise are random, they are canceled out in the addition of the photographing signals a plurality of times, and are reduced from the sum signal. Therefore, the S/N of the addition signal is high. Moreover, in the added signal, the signal level of the bright part is increased by n times, and the signal level of the dark part is increased by n times, and the relative difference between the bright part level and the dark part level becomes large, making it easy to distinguish between the bright part and the dark part. Be accurate. the result,
It is easy to set a threshold value for classifying the abutting part (dark part), and the classification of light and dark with respect to the threshold value becomes accurate, so that the state of the abutting part can be accurately detected.
Furthermore, if there is local dirt or dust on the butt end of the steel plate, the change in light intensity at this part will remain in the summed signal, but the signal taken multiple times to obtain the summation signal must be taken in the direction along the butt line. Since the photographing means is moved to different positions along the abutment line, the proportion of signal components corresponding to local dirt or dust in the added signal is extremely low, and its influence is reduced. .

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

〔Example〕

FIG. 1a shows a mechanical structure of an embodiment of the present invention. A CCD camera 5, which is a photographing means, is fixed to the first base 22 via a vertical adjustment mechanism 21a and an inclination adjustment mechanism 21b. A laser beam irradiation head 23, which is a welding torch, is also fixed to the first base 22 via a vertical adjustment mechanism 24a and an inclination adjustment mechanism 24b. A halogen lamp illuminator 4 is coupled to the camera 5 .

The first base 22 is supported by a second base 26. A threaded rod 25 pivotally attached to the second base is screwed into a screw hole drilled in the first base 22. A rotating shaft of a pulse motor 27 is coupled to one end of the threaded rod 25. Threaded rod 25 and pulse motor 27 are the x-axis drive mechanism.

When the pulse motor 27 rotates forward, the first base 22 moves forward in the x direction. That is, the camera 5 and the head 23 move together in the positive x direction. When the pulse motor 27 reverses, the first base 22
moves in the opposite direction in the x direction. i.e. camera 5
and the head 23 move together in the opposite direction in the x direction.

A rail groove is cut on the lower surface of the block 27 which is integral with the second base 26, and this rail groove rides on the y-axis guide rail 29. Guide rail 2
The direction in which 9 extends is the y direction, and the x direction is perpendicular to this. A screw hole is bored in the block 27, and a threaded rod 28 is screwed into this screw hole.
An output shaft of a speed reducer 30 is coupled to one end of the threaded rod 28 . A rotating shaft of a DC motor 31 is coupled to an input shaft of the reducer 30 . The output shaft of the reducer 30 also has a rotating plate 32 of a rotary encoder.
are combined. The threaded rod 28 and the DC motor 31 are the y-axis drive mechanism, and the photo sensor unit 33 that detects the slit in the rotating plate 32 is the second
This is base movement synchronization pulse generation means.

When the DC motor 31 rotates forward, the threaded rod 28 rotates forward, and the second base 26 moves forward in the y direction. That is, the camera 5 and the head 23 move together in the y direction. When the motor 31 reverses,
The threaded rod 28 is reversed and the second base 26 moves in the backward direction in the y direction. That is, the camera 5 and the head 23 move back together in the y direction. Second base 26
When it reaches a certain position on the y-axis during backward movement, the switch 34 is closed. In this embodiment, the second base 2
The position where the switch 34 is closed is the home position (standby position).

Note that the steel plates 1 and 2 to be butt-welded are butt-welded approximately directly below the center of the field of view of the camera 5, with their leading and trailing ends approximately parallel to the y-axis.

The camera 5 shown in FIG. 1a has the following features as shown in FIG.
A butt part state detection device that detects the position and gap of the butt part is connected to the motors 27, 31, etc. shown in FIG. 1, and a tracing bias control device and laser beam welding device shown in FIG. has been done.

First, the state detection device of the abutment part shown in Fig. 3 is
The description will be made with reference also to FIG. 1b and FIG. 2. FIG. 1b shows only the relationship between the butt-portion photographing head 6 (camera 5 and illuminator 4) shown in FIG. 3 and the steel plates 1 and 2 to be butt-welded.

The optical axis of the camera 5 is perpendicular to the surfaces of the butt steel plates 1 and 2. The illuminator 4 illuminates the steel plates 1 and 2 at an angle of θ with respect to the vertical line, with the illumination optical axis aligned with the center of the field of view of the camera 5 on the surfaces of the steel plates 1 and 2.
The head 6 is y parallel to the butt line 3 of the steel plates 1 and 2.
mechanically scanned in the direction. The light irradiation angle θ of the illuminator 4 is 30 to 40 degrees. This angle is the steel plate 1, 2
The purpose of this design is to increase the contrast between brightness and darkness at the side edges of the frame and to make side edge detection more accurate.

The arrangement direction of the one-dimensional CCDs in the CCD camera 5 is the x direction orthogonal to the y direction, and the photodetection signals of the photoelectric conversion unit elements arranged in one row or several rows are serially transmitted in time series by electronic scanning from the camera 5. is output to. FIG. 2 shows the relationship between the butt line 3 of the steel plates 1 and 2, the arrangement of the CCDs 10 in the camera 5, and the signal 11 obtained from the camera 5. In FIG. 2, 7 and 8 are clampers not shown in FIGS. 1a and 1b. The edges of these clampers 7 and 8 are machined at an angle of approximately 45 degrees so that the amount of reflected light given to the camera 5 is much smaller than the amount of reflected light from the steel plates 1 and 2. Part of the light that hits the 45-degree angled surfaces of the clampers 7 and 8 and the surfaces of the steel plates 1 and 2 between the clampers 7 and 8 is converted into an electric signal (video signal) by the camera 5.

The video signal is high in the shooting range between the clampers 7 and 8, as shown by 11 in FIG.
Low in shooting range above 8. At the butt line 3, the light passes through the butt gap or is scattered in various places at the butt edge, so the video signal level is lower than that at the surface of the steel plates 1 and 2, but since the butt gap is narrow, the level drop is small.

In FIG. 2, FL is a filter centered on the wavelength of the highest intensity of light emitted by a halogen lamp. In order to reduce the attenuation of the required wavelength in this filter FL, the optical attenuation rate of the filter FL is set to be small. Therefore. There is also considerable transmission of light other than the required wavelengths.

FIG. 3 shows the configuration of a signal processing device connected to the CCD 10 shown in FIG. 2. In this embodiment, the CCD 10 has 2048 photoelectric conversion elements arranged in a row, and one line of video signal of this CCD 10 includes optical information of 2048 pixels. The drive circuit 12 reads and energizes the CCD 10,
A read signal (video signal), a Y pulse (line synchronization pulse: electronic sub-scanning synchronization pulse) for line identification in repeated reading of one line, and an X pulse (pixel synchronization pulse) indicating pixel division of the read signal in one line. Outputs electronic main scanning synchronization pulse). The video signal is amplified to a predetermined range by an amplifier 13 and provided to an A/D converter 14. The X pulse is applied as a write shift pulse to the buffer memory 17 through the OR gate 18 and also to the microprocessor 19. The Y pulse is applied to the microprocessor 19. Drive circuit 1
2 is given a start/stop signal from the microprocessor 19. Drive circuit 12
outputs a video signal in line sections at a predetermined repetition period while a start signal is applied,
It outputs an X pulse along with the video signal, and a Y pulse between lines. When the stop signal is applied, the drive circuit 12 stops these signals and holds the input terminal of the amplifier 13 at the equipment ground level.

In this embodiment, the A/D converter 14 is of a parallel output type, and outputs digital data (e.g., 8 bits) indicating the level of an input analog signal (video signal) in parallel (8-bit parallel output). This digital data is added to adder 1
It is applied to the 5po addition input terminal A. Each bit signal of the sum output end data of the adder 15 is applied to the buffer memory 17 through one of the AND gates 16 whose number is equal to the number of bits (8 bits) of this data (8 bits). and gate 16
The gate is turned on or off depending on the output signal of the microprocessor 19. When the gate is off, the output terminal of the AND gate 16 becomes the equipment ground level.

In this embodiment, the buffer memory 17 has 2048 bits per line, and is composed of a shift register (parallel 8
This is a shift register with 2048 shift stages for bit data input. The leading end of a 1-line video signal consisting of photodetection information of 2048 pixels of CCD 10 is called the first pixel signal, the second one is called the second pixel signal, and the last one is called the second pixel signal. Calling it a 2048 pixel signal, when the video signal of the currently read line is applied to the memory 17 with the video signal of the previous line stored in the buffer memory 17, the output of the memory 17 is the first pixel signal of the previous line and is the input of the memory 17. is the first line of the currently read line.
This becomes a pixel signal. That is, when data obtained by A/D converting the video signal of each line of the CCD 10 is continuously supplied to the memory 17, the output of the memory 17 and the input of the memory 17 are the i-th pixel signal of the previous line and the i-th pixel signal of the currently read line. It becomes an i pixel signal. Actually, the output of the memory 17 is sent to the microprocessor 19.
and the addition input terminal B of the adder 15 to AND the read data (i-th pixel signal of the current read line) A of the CCD 10 and the sum of the output data (i-th pixel signal of the previous line) B of the memory 17. It is applied to the memory 17 through the gate 16. When two consecutive lines of read data are given to the adder 15, the memory 17 stores two consecutive lines of the same pixel data.
The sum data obtained by adding the read data of No. will be stored. When three consecutive lines of read data are supplied to the adder 15, the memory 17 stores sum data obtained by adding the three consecutive lines of read data. Similarly, when n lines of read data are continuously supplied to the adder 15, the memory 17 stores sum data obtained by adding the read data of the continuous n lines. In this embodiment, video signals are added in this manner.

These additions increase the required number of bits for the sum data C, so in order to reduce the required number of bits for the sum data C, the amplifier 13 and the A/D converter 14 are configured as shown at 11 in FIG. The level Lb shown in Figure 2 is used as the base for the video signal (the level that indicates 0 in digital data), the video signal level below Lb is expressed as 00000000 in digital data, and the level exceeding Lb is expressed as the base level (0). )
The potential settings are converted digitally.
This set value is a level for identifying whether the steel plates 1 and 2 are present or not. As a result, video signal 11 (second
The high frequency noise shown in the figure) is smoothed, and a signal (the contents of the memory 17, digital data) with a large level difference between the bright part (smooth surface of the steel plate) and the dark part (butt part) is obtained. This digital data is represented by a waveform 21 shown in FIG. 2 at an analog signal level. According to this waveform 21, high frequency noise is reduced and the level difference between the bright and dark areas is large, so the dark areas can be easily recognized.

In the embodiment shown in FIG. 3, the microprocessor 19 controls data input to the memory, that is, addition, and determines the dark part (matching part 3) of the waveform 21 based on the data written to the memory 17 (addition data). Detect position and width (butt gap).

4 and 5, the microprocessor 1
9 shows the control operations related to position detection and gap detection of the abutting portion 3. Microprocessor 1
9 is a microprocessor 2 that controls a mechanical scanning drive system that drives the head 6 in the y direction and the x direction.
0 (hereinafter referred to as host), and receives instructions (data requests) from this host 20.
The host 20 requests data from the microprocessor 19 at a predetermined period while driving the head 6 in the y direction at a predetermined speed. Every time there is a data request, the processor 19 detects the position and width of the butt portion 3 and provides data indicating these to the host 20. Based on these data, the host 20 develops two-dimensional pattern data indicating the position and width distribution of the abutting portion on the memory, and controls the scanning drive of the laser head 23 based on this pattern data.

First, refer to FIG. When the power is turned on, the microprocessor (hereinafter simply referred to as microcontroller)
Step 19 executes initialization (Step 1: hereinafter the word "step" will be omitted in parentheses), clears internal registers, flags, timers, etc., and sets the input/output port to a standby state. Next host 20
(2) and waits for a data request to arrive from the host 20. In addition, upon receiving the ready signal, the host 20 learns that the detection device shown in FIG. .

When there is a data request from the host 20, the microcontroller 1
9 completes the ready to the host 20 (sets busy: 4) and clears the memory 17 (5). In this memory clear (5), the microcomputer 19
L that gates off the signal to AND gate 16
Give 2048 or more pulses to the ORGator 17 as a level. Next, the microcomputer 19 clears the address counter (an internal register that indicates the pixel number of data written to the memory 17), and clears the number counter (an internal register that indicates the number of lines of data written to the memory 17). (6). Next, the signal to the AND gate 16 is set to gate on level H.
and gives a start signal to the drive circuit 12 (7).
Next, monitor the signal from the drive circuit 12 (8, 10),
When the X pulse (pixel synchronization pulse) arrives, the address counter is incremented by 1 (9), and when the Y pulse arrives, the number counter is incremented by 1. And each time the Y pulse is counted up,
Compare the contents of the number counter with n (number of additions)
(12). When the content of the number counter is n, it means that the addition data C obtained by adding video signals for a predetermined number of lines n is stored in the memory 17. The address register contents are 2048.
Therefore, the microcomputer 19 instructs the drive circuit 12 to stop (throughput of the start signal: 14), and adds an addition register A (register for writing the sum for calculating the average value M) used for subsequent calculations and data storage. Addition count register (register to write the number of additions to calculate the average value M), register M (register to write the calculated average value), register C _L (register to write the darkest data), register AC _L S (register to write the first address data from which the darkest data was obtained), register AC _L E (register to write the last address data from which the darkest data was obtained), register Adc (register to write the dark center position) ), register W (register to write the dark area width), up flag,
Clear down flag etc. (15).

Next, the readout of the memory 17 is shifted one pixel at a time (19 to 21), and it is determined whether the readout pixel data (sum of data for n lines of pixels at the same position on the line) exceeds 0 (16 ), if it exceeds 0, add the contents of addition register A and update the added sum in addition register A (17). When the update memory is updated in this way, proceed to the flow shown in Fig. 5, The contents of the addition count register m are counted up by 1 (18). Then, it is determined whether the contents of the address register are 0 or not (20). The contents of the address register are 0
, all 2048 pieces of data in the memory 17 are read out, added to register A, and the number of additions is written to addition number register m. Note that when reading data from the memory 17 for this addition, the input A of the adder 15 is 0, and the output data of the memory 17 is applied to the input terminal of the memory 17 through the adder 15 and the AND gate 16. , Even after reading 2048 pieces of data in this way, the memory 17
retains the same data as before reading. In this state, the microcomputer 19 determines that the detection field of view is the steel plates 1 and 2.
The contents of addition register A are compared with K to determine whether it is above or outside the steel plate (39). K is a value lower than the minimum value of the sum of the added signal data when the field of view is on the steel plates 1 and 2. If A is less than K, the field of view of the camera 5 is outside the steel plates (the field of view does not extend to or passes through the side edges of the steel plates 1 and 2), so the microcomputer 19
Data indicating "outside the side edge" is transmitted to the host 20 (40), and the process returns to step 2.

If A is greater than or equal to K, the field of view of the camera 5 is on the steel plate, so the microcomputer 19 next calculates the average value M, which is obtained by dividing the contents of register A by the contents of addition count register m.
is calculated and written to register M (22). The level represented by the average value M is the one-dot chain line level shown in waveform 21 in FIG.

The microcomputer 19 then reads the memory 17 by 1.
Shift pixel by pixel (25) and read out pixel data (sum of data for n lines of pixels at the same position on the line)
Check whether C exceeds M. This is pixel No.
Since the reading is performed sequentially from 1 to 2048, the read data C is less than M at first, but becomes more than M at a certain point, becomes less than M at the matching part 3, becomes more than M again after passing the matching part 3, and finally becomes less than M. becomes.
The microcomputer 19 follows this process and detects the butt portion 3. That is, first, when the number exceeds M, the process proceeds to steps 27 and 28, and the up flag is set. M
If the read data C becomes less than M after the UP flag is set, the step is started.
23, 24, 29, and 30 to set the down flag, store the data C at that time in the lowest register _CL (31), and store the contents of the address register in registers AC _L S and AC _L E ( 32). If the subsequent read data C is smaller than the contents of the register C _L , the process advances from step 33 to steps 31 and 32, stores the data C in the lowest register C _L (31), and stores the contents of the address register in the register AC _L. S
and memory in _ACL E (32). If the subsequent read data C is equal to the contents of the register C _L (34), the dark part continues, so the address of that data C (contents of the address register) is stored in the register.
Update memory only to AC _L E (35). When the subsequent read data C exceeds M, it means that the read has exceeded the dark area (matching area 3), so step
After steps 23, 27, and 38, proceed to step 36 and below. In this case, the read data C (added value for n lines) of the darkest part is written in the lowest register C _L , and the contents of the register AC _L S are the beginning of the read data C of the darkest part. This indicates the address (pixel number), and the contents of the register _ACLS indicate the end address (pixel number) of the read data C of the darkest portion.

Therefore, the microcomputer 19 calculates the average value Adc of the contents of the register _ACLS and the contents of the register _ACLE ,
A value W is calculated by subtracting the contents of the register _ACLS from the contents of the register _ACLE (36). This Adc is
The center position (pixel number) of the dark part (matching part 3) is shown, and W shows the width of the dark part (matching part 3). The microcomputer 19 then transfers these data Adc and W to the host 20 (37), returns to step 2, and
A ready signal is output to the host 20.

In addition, in the above embodiment, the dark area position and width are detected using the average value M as the threshold value, but the dark area position and width are detected by subtracting a predetermined value from M, or by multiplying M by a predetermined number (greater than 0 and smaller than 1). The value may be used as a threshold.

As described above, the detection device shown in FIG. 3 creates an addition signal addressed to the pixel by adding n times of electronic scanning video signals every time there is a data request from the host 20. It is determined from the outside whether it is inside the steel plate, and if it is outside the steel plate, data indicating this is sent to the host 20, and if it is inside the steel plate, the x position data Adc and gap data W of the butt portion 3 are sent to the host 20. Therefore, the host 20 sends data requests to the microcomputer 19 at predetermined intervals from before the field of view of the camera 5 enters the steel plate until it passes through the steel plate, thereby determining the position Adc(x) and A gap W is obtained. In addition, if the data sent from the microcomputer 19 is less than Lb in FIG.
If the signal level is above Lb, it is recognized that it is inside a steel plate. When the data changes from data indicating outside the steel plate to data indicating Adc and W, it is recognized that the field of view of camera 5 has reached the side edge of the steel plate, and Adc and W
It can be recognized that the field of view of the camera 5 has passed through the side edge of the steel plate when the data changes from data indicating the outside of the steel plate to data indicating outside the steel plate. Next, the configuration and operation of the tracing control system shown in FIG. 6 will be explained. In addition to the microprocessor 19, the host microprocessor 20 includes an operation display board 39, a laser beam welding controller 40, a mechanical scan synchronization pulse processing circuit 37, and a constant speed motor energizing circuit. 3
6. Waveform shaping circuit 38, pulse motor driver 3
5 is connected.

The pulse processing circuit 37 energizes the light emitting diode of the photo sensor unit 33 to emit light, and causes the rotary plate 32 to emit light.
The output voltages (slit detection pulses) of the two phototransistors that detect the steel passed through are shaped into waveforms, and according to the phase difference between the two sets of pulses,
Rotation direction of the rotary plate 32 (rotation direction of the threaded rod 28:
A rotation direction signal indicating the movement direction of the second base 26 on the y-axis is generated, and one set (A) of the two sets of pulses and the rotation direction signal are provided to the microprocessor 20. Pulse A is applied to the interrupt input. As will be described later, the microprocessor 20 registers pulse A when the switch 34 is closed (the second base 26 is in the home position) as 0, and when the rotation direction signal indicates forward rotation. The pulse A is counted up in register Y, and the pulse A is counted down in register Y when the rotation direction signal indicates reverse rotation. Therefore, the count value of register Y is
Regardless of whether the second base 26 moves back and forth,
y of the second base 26 based on the home position
It will indicate the direction position.

The motor driver 36 is a DC motor energizing circuit that includes a plurality of sets of pulse oscillators or frequency dividers with different frequencies and a PLL control circuit, and is specified by the speed instruction data in the direction indicated by the forward and reverse instruction data. The motor 31 is urged to rotate at a constant speed. Microprocessor 20 provides speed indication data.

The waveform shaping circuit 38 shapes the waveform of the switching signal of the switch 34 and removes short-cycle switching signals due to chattering.

The pulse motor driver 35 energizes each phase of the pulse motor 27. The phase activation signal is provided by microprocessor 20. Processor 20
holds phase energization data for one cycle of the pulse motor in an internal memory, and sequentially supplies the phase energization data to the driver 35 in a predetermined order. Forward rotation and reverse rotation are determined by whether the data is read out in the forward or reverse order.

The operation display board 39 is an interface device with the operator, having function selection keys, operation instruction keys, data input keys, indicator lights, character displays, etc., and provides operation instructions and reference data to the microprocessor 20. The operation display board 39 is also an operation display board for the laser beam welding device and provides operation instructions and reference data to the laser beam welding controller 40.

The control operations of the host microprocessor 20 are shown in FIGS. 7-11. To explain this below,
When the power is turned on, the microcomputer 20 is initialized (40)
Execute to clear internal registers, timers, flags, etc., and set the input/output ports to standby signal levels. Then, the status is read (41). This status reading is to read whether the microcomputer 19 is ready or not, whether the controller 40 is ready or not, and status signals of safety protection sensors and sensors of various parts of the laser beam welding apparatus (not shown). In this status reading, the process proceeds to abnormality processing (42) for detecting an abnormal state that cannot be resolved by waiting, and executes abnormality response processing such as turning on an abnormality indicator light. If no abnormality is detected, or if it becomes normal after abnormality processing (42) (43), the abnormality set such as abnormality display is cleared (44), and input reading from the operation display board is performed (45).

In this input reading, when an input indicating home position set is detected (46), the HP flag is set and flags indicating other equivalent instruction states are cleared (47). When an input instructing execution of mode A (butt portion position and gap detection) is detected (48), the mode A flag is set and flags indicating other equivalent instruction states are cleared (49).
When mode B (copy welding) input is detected (50), the mode B flag is turned off, and flags indicating other equivalent instruction states are cleared (51). When an input instructing mode C (butt portion position and gap detection followed by copy welding) is detected, the mode C flag is cleared and flags indicating other equivalent instruction states are cleared (53). When an input instructing start (execution) is detected (54), the process proceeds to the flow shown on page 8. When another input is detected (55), processing corresponding to the input is performed (56). Typical other inputs include speed instruction data input that instructs the speed of the motor 31, input of data indicating the maximum allowable butt gap value Wm, and the center of the field of view of the camera 5 and the welding head 2.
Inputting data indicating the distance in the x direction from the laser irradiation center of 3 (converted value of the number of phase switching energizing pulses of the pulse motor 27), and inputting data indicating the distance in the y direction between the center of field of view of the camera 5 and the laser irradiation center of the welding head 23 This is the input of data indicating the distance (converted value of the number of slits on the rotary plate 3), and when these inputs are received, they are stored in a predetermined register for storing reference data.

After inputting an operation mode selection and data on the operation display board 39, the operator operates the start key to instruct the start. When the start is instructed, the microcomputer 20 proceeds from step 54 in FIG. 7 to the flow in FIG. 8, and refers to the operation designation flag in steps 57, 69, 105, and 146.

Home position set: When a start is instructed, if the HP flag is present (54-57-58), the state of the switch 43 is referred to (58), and if it is closed, the second base 26 is set to the home position. Therefore, the register Y that counts the position in the y direction is cleared (63), the home position lamp is turned on (64), and the presence or absence of the HP flag is checked (65). Since there is an HP flag, clear the HP flag (66) and return to reading the status (51) to have the next input.

If the switch 34 is not closed, the timer (program timer) T1 is set (59), the driver 36 is instructed to reverse the motor 31 at low speed (60), and the switch 34 is closed (61) or the timer T1 is set (59).
1 waits for timeout (67). When the switch 34 is closed, the driver 3 stops the motor 31.
6 (62), and then register Y in the same way as above.
Clear, turn on the home position lamp (64), clear the HP flag (66), return to status reading (41), and wait for the next input. When the timer T1 times out, it means that the second base 26 did not reach the home position due to the backward drive of the second base 26 during the time T1. To ensure safety, the motor 31 is stopped here (68) and the process returns to reading the status (41). At this time, the home position lamp does not light up and the HP flag is not cleared.
When the operator operates the start key again, the process proceeds to steps 54-57-58-59, and the second base return drive of the longest length T1 is performed again. The reason why only the maximum length T1 is returned for each start instruction by the operator is to prevent reverse energization for a long period of time in the event that the y-axis drive mechanism is abnormally locked or the switch 34 is broken. According to the return drive control with the longest T1, when the second base 26 is far away from the home position, it is returned to the home position with several start instructions under the supervision of the operator, and is returned to the home position. 1 when it gets close
The home position is set at the start of the inning. When giving the start command several times, the operator focuses his attention on the second base 26, so
The motor 31 is never locked and energized for a long period of time.

Execution of mode A (butt position & gap detection): When a start is instructed and there is a mode A flag (54-57-69-70-58), first step 58 is executed.
~64 home positions are performed, and the second base 26
Set to the home position, initialize register Y (63), and then switch to mode A in steps 71 to 98.
Let's go through the motions. That is, first, the motor driver 3
The timer T2 is set by giving speed instruction data and a forward transfer instruction to the port INT1 (71), and interrupt processing of the port INT1 is allowed (72). By allowing this interrupt processing,
Pulse A corresponding to the rotation direction signal of the processing circuit 37
A count-up (rotation direction = forward rotation) or countdown (rotation direction = reverse rotation) is started.

This interrupt processing will now be explained with reference to FIG. When one pulse of pulse A arrives at INT1,
The microcomputer 20 proceeds to the interrupt processing shown in FIG. 9, where it first refers to the rotation direction signal of the processing circuit 37 (102), and if it indicates normal rotation, sets 1 to the current content Y of the register Y. The value obtained by subtracting 1 from the current contents Y of register Y is updated and stored in register Y (104). ). Then, the process returns to the main routine (the step immediately before proceeding to interrupt processing). This process is executed every time one pulse A arrives. This results in
Thereafter, the contents of register Y indicate the position of the second base 26 in the y direction.

Now, after setting the interrupt permission in step 72 of FIG. 8, the microcomputer 20 advances to step 73 of FIG. 10 and waits for the timeout of T2 (73). T2 is a value approximately equal to the longest time from when the motor 31 is started to rotate normally until the rotational speed of the motor 31 stabilizes at the specified speed. The input on the operation display board is monitored until the time has elapsed to see if there is a stop instruction input (74). And when a stop instruction is input,
Then, the moder 31 is stopped (75), the mode A interruption flag is set (76), and the process returns to the status reading (41).
After stopping the motor 31 in this way, if a start instruction is given again, steps 54-57-69-70-
The process proceeds to step 100 to clear the mode A interruption flag, then gives speed instruction data and a forward rotation instruction to the driver 36 (101), and proceeds to step 77 onwards.

Assuming that T2 has timed out in step 73, a T3 timer that determines the sampling period for detecting the position and gap of the abutting portion 3 is set (77), and a data request is given to the microcomputer 19. Data is then received from the microcomputer 19 (data outside the side edge at step 40 or Adc and W at step 37) (79), and if the data indicates outside the side edge (80), the process proceeds to steps 81-82. It has a time over of T3. During this waiting period, the input on the operation display board is monitored to see if there is a stop instruction input (83). When a stop instruction is input, the motor 31 is stopped (84), a mode A interruption flag is set (85), and the process returns to reading the status (41). After stopping the motor 31 in this way, if a start instruction is given again, the process proceeds to steps 54-57-69-70-100 to clear the mode A interruption flag, and then send the speed instruction data and forward rotation instruction to the driver 36. (101) and proceed to step 77.

Continuing the explanation assuming that there is no stop instruction, when T3 times out, timer T3 starts again.
(77), sends a data request to the microcomputer 19 (78), receives the data (79), and checks whether the data indicates outside the side edge (80). Starting from the home position until the field of view of the camera 5 reaches the root side ends of the steel plates 1 and 2, data is received from the microcomputer 19 at the T3 period in this manner. The field of view of camera 5 is steel plates 1 and 2
When the side edges of are reached, the data will be indicative of Adc and W. Then, the microcomputer 20
Go from 80 to 87 and set the board flag. Then, store the contents of register Y (distance data from the home position to the starting edge of the steel plate) in the input end register, clear register Y, and register Ty (register that stores sampling number data on the steel plate).
Clear (88). As a result, the contents of register Y will now indicate the position in the y direction from the start end (root side end) of the steel plate, and the distance from the home position to the start end (root side end) of the steel plate will be in the input end register. It will be retained. Next, the microcomputer 20 determines an address using the contents of register Ty (sampling number from the root side end of the steel plate), and writes the contents Y of register Y (steel plate Adc (x position data of the abutting part 3 obtained from the microcomputer 19), and W (gap data of the abutting part 3 obtained from the microcomputer 19) are stored in memory (89). In the first write, Ty=
0, Y=0, Adc=x of the butt part of the starting end on the root side
Position, W = gap at the butt part of the starting end on the root side,
It is.

Next, the microcomputer 90 sets the contents of register Ty to 1.
Update memory with the value added to register Ty (90),
Has a timeover of T3 (82). In other words, it waits for the next sampling timing. When T3 times out, it sets the T3 timer again (77) and sends a data request to the microcontroller 19 (78).
Receive data from microcomputer 19, and the received data
If it is Adc and W, the process goes through steps 80 and 86, and then goes to step 89, where the address is determined by the contents of register Ty and is written in register Y.
The contents Y, Adc and W are stored in memory (89). In the second writing, Ty = 1, Y = position in the y direction from the starting end (left end) on the root side, Adc = x position of the abutting part at the position in the y direction, W = gap of the abutting part at that position. . Hereinafter, while the data received from the microcomputer 19 is Adc and W, steps 77-78-79-80-86-89-90-82-77 are repeated, and the butting portion of each point on the steel plate in the y direction is The x position data Adc and the gap data W are sequentially written in the data table in correspondence with the sampling numbers.

When the data received from the microcomputer 19 indicates the outside of the side edge, the process goes through steps 80-81-91, and then in step 92, the board exit flag is set. Then, the contents of register Y (steel plate width) are stored in the output end register, timer T4 is set (94), and the timer T4 times out. This T4 is a time limit for adjusting the stop position of the third base 26, and firstly,
When the motor 31 is stopped and the second base 26 is stopped, and then the motor 31 is driven in reverse for butt welding, the head 23 moves to the right end of the steel plate after the motor 31 has stabilized at the specified speed. It has the meaning of arriving at the start-up distance. 1st
As shown in figure a, the camera 5 is placed on the root side (left end) of the butt part, welding starts from the right end, the welding head 23 is placed on the right side, and the y distance between the camera 5 and the laser irradiation point of the head 23 is If the directional distance is relatively long and is equal to or greater than the run-up distance, T
There is no need to take four periods. If the distance is short,
This is meaningful when the positions of the camera 5 and the head 23 are replaced.

Now, when T4 times out, the motor 31 is stopped (97), and the presence or absence of the mode A flag is checked (98). If the mode A flag is present, the mode A end indicator light is turned on, the mode A flag is cleared (99), and the process returns to status reading (41) to wait for the next input.

By the operation in mode A explained above, the x position data and gap data from the starting end (left end) on the funnel side to the opposite end (right end) of the butt portion 3 of the steel plates 1 and 2 are changed to the steel plate from which it was obtained. Upper position data Y
(The left end is the base point 0) and is stored in the data table in correspondence with the sampling number. Also, in the input side register, the position of the route side start end from the home position of camera 5 is stored in the output side register. The steel plate width (butt line length) is stored in memory, and the contents of the register Y are the y-direction position data of the camera 5 from the starting end (left end) on the route side.

Although not shown in detail in the flowchart, when there is an input from the operation display board instructing the display of memory data in the data table, the memory data is read and displayed in steps 55 and 56.

Execution of mode B (welding tracing control): This mode B is scheduled to be executed after mode A is executed. Therefore, normally, after mode A ends, the operator gives mode B instruction input and start instruction input to the operation display board.

When the start is instructed, if the mode B flag is present (54-57-69-105-107A=Figure 11),
First, set the contents of register Y to DL (camera 5 and head 2).
The value obtained by adding the distance difference in the y direction of 3: the number of slits on the rotary plate 32 (inputted in advance from the operation display board) is updated and stored in register Y (107A). That is, the inner depth of the register Y is corrected to the laser irradiation position (y direction) of the head 23 with the starting end (left end) on the root side of the butt portion 3 as the base point O. Next, the data table read address i is established as the base point O (sampling No. 0) (107B), the gap data Wi of the address i is read from the data table (108), and this is set to the maximum allowable value Wm (previously set on the operation display board). (109). If Wi is less than Wm, the gap at the butt part is appropriate, so in order to check whether the gap at the next sampling point is appropriate, i is incremented by 1 (111).
Also, data Wi is read out and compared with Wm. If the gap is appropriate, this process is repeated one after another, and when i reaches the value of the register Ty (110), the appropriateness of the gap at all sampling points has been determined. The contents of the side end register (board width) and the contents of register Y (route start end: laser irradiation position of the head 23 with respect to the left end) are transmitted (115). Note that if the read gap data Wi is greater than Wm, the gap is too wide, so the Y data Yi of address i (of the too wide gap,
position from the left edge of the steel plate) on the character display, and lights up the gap abnormality indicator light (112).
Waits for a stop instruction input or a continuation instruction input on the operation display board (113, 114).
That is, at that point, updating and reading of the gap data from the data table is stopped. If there is a stall input in this stopped state, the process returns to status reading (41). In this case, the operator should issue a home position instruction, mode A instruction, or mode C instruction again before and/or after the gap adjustment. If this exists, execute the flag set (47-53) in Figure 7,
After waiting for a start instruction, the process proceeds to the process corresponding to the set flag. If there is a continuous input in the above-mentioned stopped state, the next gap data will be read out, etc.
At this point, if the read data Wi is equal to or greater than Wm, the process similarly stops there.

When all sampling data Wi is read out and the required data is sent to the controller 40 (115),
It also waits for the controller 40 to send a ready signal indicating that it is possible to start laser beam welding (116). While waiting, the input on the operation display board is monitored, and if there is a change input, the process returns to status reading (41). If there is no change input and the controller 40 sends a ready message, it gives speed (welding speed) instruction data and reverse rotation instruction data to the motor driver 36 (119). As a result, the second base 27 starts to move backward.

Note that the controller 40 is given a rotation direction signal and pulse A by the processing circuit 37, and
The controller 40 first receives the contents of the output end register (steel plate width) and the contents of the register Y (head 2).
3 (laser beam irradiation position = steel plate width + irradiation position deviation amount from the right edge of the steel plate) is given, and the difference between these (contents of register Y - contents of output end register) is calculated from the starting point of the backward movement of the head 23. Steel plate 1, 2
Indicates the distance to the welding start end (right end). The controller 40 counts down the number of arrivals of pulses A based on the contents of the register Y given in step 115, tracks the position of the head 23, and determines that the position of the head 23 matches the contents of the output end register given earlier. The microcomputer 20 starts laser beam projection a little before this, and instructs the backward drive (119).
Data L (previously input from the operation display board) indicating the distance difference in the x direction between the center of the field of view of the camera 5 and the laser beam irradiation position of the head 23 is stored in the register Adc ₂ (120), and the register Adc ₂
The contents of the data table are read into the register Adc ₁ , the data Adc, W, and Y of the address Ty of the data table are read into the register Adc ₂ , the register W, and the register Y ₀ , respectively (121), and the data of the register W is transmitted to the controller 40. If the sampling number of the last data written in the data table is Sf, the contents of register Ty are Sf at first, so
The W data first transmitted to the controller 40 is
This figure shows the gap at the welding start end (right end) of the butt portion 3. At this point, the head 23 has also not reached the welding start end. Next, microcomputer 20
is the current x position of head 23 (register Adc ₁
The number of complementary energizations Px required to align the position (contents of register Adc ₂ ) with the target position (contents of register Adc 2) is calculated (123). That is, the number of energizing pulses required for the pulse motor 27 is calculated. Then, find the difference (Y-Y ₀ ) between the current y-direction position Y of the head 23 in the y-direction and the y-direction position Y ₀ that should be the target position (Adc ₂ ),
Phase switching period of pulse motor 27 (pulse A unit)
Pt is calculated (124), and it is checked whether the required number of pulses Px is 1 or more (125). If it is 1 or more, pulse energization of the pulse motor is required, so
Referring to the polarity of Adc ₂ - Adc ₁ (target position in the x direction - current position), the pulse motor 27 is energized by one unit phase switching (1
pulse energization) (126), update the required number of pulses Px to a smaller value by 1 (127), and perform the steps shown in Figure 12.
Proceed to step 128 and set timer Pt (this is a program timer that counts Pt pulses A).
Wait for Pt time-over (Pt count up of pulse A). While waiting, the input on the operation display board is monitored and a stop input is checked (130). When there is a stop input, the motor 31 is stopped (131), a mode B interruption flag is set (132), and the process returns to status reading (41). Status reading (41)
If a start instruction is input after returning to , the mode proceeds to steps 54-57-69-105-106-144 and mode B is entered.
Clear the interrupt flag (144) and mode driver 3
The speed instruction data and reverse rotation instruction are given to step 6 (145), and the process proceeds to step 125. In other words, the process returns to mode B tracing control.

Now, proceeding with the explanation assuming that there is no stop input, when Pt times out (completion of counting Pt pulses A) (129), the required number of pulses Px
Checks if is greater than or equal to 1 (125). If it is 1 or more, pulse energization of the pulse motor is required, so refer to the polarity of Adc ₂ - Adc ₁ (target position in the x direction - current position) and rotate in the forward or reverse direction depending on the polarity. The pulse motor 27 is energized by one unit phase switching (1 pulse energization) (126), and the required number of pulses Px
is updated to one smaller value (127), and the process proceeds to step 128 shown in FIG.
Set a program timer (to count Pt pulses) and wait for Pt time-over (Pt pulse count up). While repeating this, the pulse motor 27 is pulse-energized at intervals of Pt, the x-direction laser irradiation position of the welding head 23 approaches the target position Adc, and Px gradually decreases accordingly. When Px becomes less than 1, it means that the x-direction laser irradiation position of the welding head 23 is aligned with the target position Adc with an error less than the minimum adjustment unit, and in addition, in step 124, Pt = (Y - Y ₀ ) / Pt
Since Pt was determined by the calculation in step 124, the difference (Adc ₂ - Adc ₁ ) between the x-direction target position Adc ₂ and the x-direction actual position Adc ₁ at the time of the calculation is calculated as Actual laser irradiation position Y and laser irradiation position _Y at the time when it should be the x direction target position Adc ₂
The y-direction interval that drives the head 23 by one unit in the x-direction by proportionally distributing it within the range of the difference (Y-Y ₀ )
Pt is calculated and the x direction is driven by 1 unit for each movement of Pt in the y direction, so when Px becomes less than 1, the y direction position also changes to Y ₀ (if Px is an integer) or Y ₀ . closest value (if Px is not an integer)
It's getting old. Therefore, proceeding from step 125 to step 133, it is checked whether the contents of register Ty are 0 (reading of all data in the data table is completed: copying control is completed).
The contents of Ty are updated to a number smaller by 1 (the data read address of the data table is updated to that of the next sampling data) (134A), and the y-direction laser irradiation position of the head 23 (content Y of register Y) is changed to step 121. Check whether the target position Y ₀ read out has been reached (134B). When Y= _Y0 , the process advances to step 121, reads out the data at the next sampling point, and performs the x-position tracing control described above (122 to 125).
~129). When 0 is detected in step 133, the laser irradiation position in the y direction of the head 23 has passed the root side start end (left end) of the steel plates 1 and 2 to the left, so the contents of register Y are transferred to the entry side end register. Update the value by subtracting DL from the contents (136A),
That is, the field of view position of the camera 5 is changed relative to the home position, the controller 40 is notified of board omission (136B), and the low speed data is updated and given to the motor driver 36 (137). In response to this, the controller 40 stops laser irradiation, and the second base 26 switches to low-speed backward movement. Next, the microcomputer 20 refers to the contents of register Y (138), refers to the state of switch 34 (139), and monitors the input from the operation display board (140), so that the contents of register Y become 0. or when there is a stop input, the motor 31
(142), turns on the mode B end indicator light, clears the mode A, B, and C flags (143), and returns to status reading (41). When the switch 34 is closed, the home position lamp is turned on (141) or the motor 31 is turned off.

Mode C (continuous execution of mode A + mode B): When a start is instructed and there is a mode C flag (54-57-69-105-146), first step
The home position set in steps 58-64 is executed, then the mode A in steps 65-97 is executed, and then the mode B in steps 98-143 is executed. That is, in this mode C, the second base 26 is first set at the home position, and then mode A is executed, that is, the second base 26 is driven rightward from the home position and the steel plates 1 and 2 are routed. Starting edge (left edge) detection-T3
Period abutment x position Adc and gap W detection - width detection of steel plates 1 and 2 (right end position detection), and finally mode B is executed. That is, after determining whether or not the gap data W detected in mode A is appropriate, if all the data is appropriate, the second base is driven to the left and the detected data is written in the data table in mode A. reads the data and controls the first base 22 to follow the butt portion, and when the head 23 comes off the steel plates 1 and 2, the second base 22
The base 26 is driven at low speed and stopped at the home position.

The operation and features of the embodiment described above are summarized as follows.

(1) Drive the second base 26 forward to remove the butt of the steel plates.
Mode A; second mode in which the x position Adc and gap W corresponding to the y direction position are detected and the detected data is memorized;
Mode B in which the base 26 is driven back and the welding head is controlled to trace the butt portion based on the data stored in memory; and Mode C in which mode A and mode B are automatically performed continuously (detected in the forward drive) There are three options available: (patching control with backward drive);

(2) In mode A, the second base 26 is driven forward, both ends of the butt line are automatically detected, and the full length of the butt line (y
direction), the x position Adc and gap W of the abutment part are detected at a sampling period of T3, and the y direction position data Y, Y, corresponding to the sampling number are detected.
Store x position Adc and gap W in data table (memory). The mechanical scanning position in the y direction is obtained by counting up the pulse A generated in conjunction with the movement of the second base 26 in the y direction, using the register Y as a counter.
The data in the data table can be read out on the display. You can print it out on a printer if necessary.

(3) In mode A, since no laser beam is irradiated, there is little optical noise to the camera 5. In addition, the video signal of the camera 5 is added n times to cancel out the noise due to optical noise and electrical noise, and the image signal is amplified n times. Since the position Adc and the gap W are detected, accurate detection with a high S/N ratio is performed.

(4) In mode B, the second base 26 is driven back, and the pulse A generated in conjunction with the movement of the second base 26 in the y direction is counted down in the register Y, and The y-direction position is obtained in the reverse process of position tracking, and data (A, Adc, and W) is read out from the data table in the reverse process of writing to the data table in mode A, and data is transferred between adjacent sampling points. The welding head 23 is controlled to follow the butt portion at equal intervals.

In other words, the sampling number to be read first is
+1, and the read data is Adc ₁ , W ₁ ,
Assuming that the sampling number to be read next is i and the read data is Adc ₂ , W ₂ , Y ₀₂ , when the contents of register _Y (laser irradiation position of head 23) is Y ₀₁ , Adc ₂ , Reads W ₂ and Y ₀₂ and gives W ₂ to the controller 40, and converts Adc ₂ - Adc ₁ (target position in the x direction - current position) into the required drive amount Px in the x direction (123),
This required driving amount Px is distributed at equal intervals to Y ₀₂ -Y ₀₁ to calculate the y-direction movement amount Pt for driving one unit in the x-direction (124). Each time Pt moves in the y direction, the first base 22 is driven by one unit.
As a result, the laser irradiation position Y of the welding head 23
When becomes _Y02 , the laser irradiation position X of the welding head 23 becomes _Adc2 . In this way, the x position left between sampling points is distributed at equal intervals during the y direction movement of the y direction position difference, so
Even when the sampling point is moved in the y direction, the laser irradiation position X of the welding head 23 accurately follows the butt portion.

(5) In mode B, all gap data W in the data table is changed to the input reference value before the copying drive.
It automatically determines whether the detected gap is correct or not by comparing it with Wm, and if the gap is inappropriate, the process stops there and waits for input instructions, so the operator can check whether the gap is inappropriate before starting the copying drive (butt welding). Recognizable. If it is unsuitable, a reconciliation correction can be made.

(6) As mentioned in (1) above, mode A (forward drive detection mode), mode B (backward drive butt copying mode)
and Mode C (forward drive detection - backward drive butt copying mode). Drive execution experiments (mode B) can be easily performed.

(7) In all modes A, B and C,
When a stop instruction is given, the second base 2
6 and the driving of the second base 22 is stopped. Thereafter, when there is no mode input and a start instruction is input, driving is resumed from the stopped state, and base driving, data processing, etc. are performed in a manner continuing from the state immediately before stopping. When a mode is input, the input mode is executed from the beginning in response to a start instruction. Therefore, even during trial experiments and actual operation, you can pause depending on the situation, and after pausing, you can of course restart the same mode or another mode from the beginning. the mode before stopping,
It can be resumed in a manner continuous with the state before it was stopped.

〔Effect of the invention〕

As described above, according to the present invention, the photographing means and the welding torch are driven forward, the position of the abutting portion is detected without welding energization, and the detected data is stored in memory, and the photographing means and the welding torch are driven back, Since the welding torch is caused to follow the position of the abutting portion based on the memory data, the position of the abutting portion can be accurately detected, and the welding torch can be caused to accurately follow the abutting portion from the welding start end. There is no need to change the photographing conditions of the photographing means or perform additional work between the detection drive for detecting the position of the butt portion and the copy drive for copy welding. Furthermore, it is possible to automatically detect the gap between the abutting portions and automatically determine whether the gap is appropriate.

[Brief explanation of drawings]

FIG. 1a is a perspective view showing the main parts of a mechanism of an embodiment of the present invention. FIG. 1b is a perspective view showing the arrangement relationship between the camera 5 and illumination base 4, which are the main parts of the mechanism, and the abutting portion 3 of the abutting steel plates 1 and 2. FIG. 2 is a block diagram showing the relationship between the abutting section 3, the camera 5, and the read signal 11 from the camera 5, FIG. 3 is a block diagram showing the configuration of the abutting section state detection device connected to the camera 5, and FIG. FIG. 5 is a flowchart showing the control operation of the microprocessor 19 shown in FIG. FIG. 6 is a block diagram showing the configuration of a copying control device connected to the mechanism drive element shown in FIG. 1a, FIGS. 7, 8, 9, 10,
11 and 12 are flowcharts showing the control operation of the microprocessor 20 shown in FIG. 1, 2: Steel plate, 3: Butt part, 4: Illuminator,
5: CCD camera, 6: Status detection head, 7,
8: Clamper, 9: Lens, FL: Filter, 1
0: CCD, 11: CCD read signal waveform, 12:
CCD drive circuit, 13: amplifier, 14: A/D converter, 15: adder, 16: AND gate,
17: Buffer Memory, 18: Or Gate, 1
9: Microprocessor (detection means, 20: Microprocessor (counting means, memory means, reading means, position control means), 21a, 24a: Vertical adjustment mechanism, 21b, 24b: Tilt adjustment mechanism, 2
2: First base, 23: Welding head, 25: Threaded rod, 26: Second base, 27: Pulse motor (x-axis drive means), 27B: Block, 28: Threaded rod,
29: Guide rail, 30: Reducer, 31: DC motor (y-axis drive means), 32: Rotating plate, 33:
Photosensor unit (second base movement synchronization pulse generation means), 34: switch, 38: waveform shaping circuit.

Claims (1)

[Scope of Claims] 1. Photographing means for converting light from the butt portion of steel plates into electrical signals; Welding torch for welding the butt portion; A first base combining the photographing means and the welding torch; Supporting the first base and the first base along the butt line y
x-axis driving means for driving in the x-direction intersecting the direction; a second base coupled with the x-axis driving means; y-axis driving means for supporting the second base and driving the second base in the y-direction; A second base movement synchronizing pulse generating means that generates one electric pulse every time the base moves a predetermined distance in the y direction; applying the electric pulse in correspondence with the forward and reverse movement directions of the second base; Counting means for subtracting count; Detecting means for detecting the x-direction position of the abutting portion of the steel plates by processing the signal obtained by photographing the photographing means; When the second base moves in the forward direction, the detecting means detects a memory means for storing the position data corresponding to the count data of the counting means; a reading means for reading position data corresponding to the count data of the counting means from the memory means when the second base moves in the reverse direction; a position control means for positioning a welding torch above a position indicated by the position data by energizing the x-axis drive means based on the position data;