JP3422687B2 - Pipe hole position automatic search method and apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an automatic pipe hole searching method,
The apparatus and the tube hole processing method using the searching method, and more particularly, the tube hole automatic searching method used when performing tube hole seal welding of a tube sheet in a heat exchanger, the apparatus, and the searching method. The present invention relates to pipe hole welding and other processing methods using.

[0002]

Conventionally, for example, a shell-and-tube type heat exchanger constituted by welding a large number of heat transfer tubes to a tube sheet is known, and a tube hole of a tube sheet in such a heat exchanger is known. Conventionally, as a welding device centering means for a pipe hole for centering the pipe hole of the welding device when performing seal welding, a moving program created from the drawing is NC.
The tape was input to the NC device for positioning, but in the method of creating a movement program from such drawings, the hole arrangement pattern (triangle, square, etc.) and pitch differ depending on the customer and model. Since the NC tape is created each time and the operation of the NC device is checked in advance, the setup work is extremely complicated.

Further, the centering means of the welding device is a pipe of the welding device by a center positioning mechanism such as a tapered center rod attached to the welding device or a floating mechanism for moving the center rod up, down, left and right, front and back. The center rod was fixed to the hole, the center rod was fixed, and the welding device was circulated concentrically to perform seal welding. However, in this centering method, the operator constantly monitors and positions with the NC device. After that, the position was finely adjusted manually.

In view of the above technical problems, the present invention automatically positions each tube hole in a tube sheet having a large number of holes such as in a heat exchanger by a three-axis NC device, thereby When performing seal welding or other processing, N caused by tube plate installation accuracy, tube plate distortion, tube hole processing position accuracy, etc.
Automatically corrects the NC device by measuring the three-dimensional position of the tube hole without contact with the C program position (up / down, left / right, front / back), and then automatically searches for the next target hole automatically. search method, and an object thereof is to provide Hisage the equipment.

[0005]

The invention according to claim 1 is
For a tube sheet with a large number of tube holes, the tube sheet distance direction (Z
(Axis) and tube plate surface direction (Χ, Y axis direction) In the tube hole position automatic search method that sequentially searches each tube hole while controlling the movement of the NC device, select the camera view as narrow view or wide view. and NC device a CCD camera mounted possible using an image processing unit that performs pattern matching between the actual tube holes and the master image captured (a reference image) with a CCD camera, a pre-optimum CCD camera and the tubesheet face Set the distance (reference distance), register the image of the tube hole as a master image in the image processing device, and switch the field of view of the CCD camera to a wide field of view.
The CCD camera captures multiple tube holes and
Find the next (next to, adjacent) tube hole by ching process
The amount of movement from the target tube hole position of
After moving the NC device by a specified pitch, the CCD camera looks
The field is switched to a narrow field of view, the amount of deviation between the master image and the position of the actually imaged target tube hole is determined by the pattern matching processing of the image processing unit, and the deviation of the NC device with respect to the target tube hole is corrected based on the deviation amount. It is characterized by performing.

According to such an invention, N caused by installation accuracy of the tube sheet, distortion of the tube sheet, processing position accuracy of the tube hole, etc.
It is possible to automatically correct the NC device by measuring the three-dimensional position of the pipe hole without contact with the positional deviation (up / down, left / right, front / back) from the C program position.

[0007]

According to also take invention, while switching alternately the field of view of CCD camera in a narrow field of view and the wide field of view, automatically and shift correction between the target pipe hole and the master image, the automatic search for the next hole to alternately Can be done

A second aspect of the present invention relates to a tube hole position automatic searching device for effectively implementing the above invention, wherein a tube sheet distance direction is set for a tube sheet having a large number of tube holes.
(Z axis) and tube axis direction (X, Y axis direction) triaxial NC device
The position of the pipe hole that sequentially searches each pipe hole while controlling the position of the pipe
In the dynamic search device, an NC device in which a CCD camera capable of selecting a narrow field of view and a wide field of view of the camera and a laser light source for emitting a slit laser in a direction inclined by a predetermined angle with respect to a light receiving direction of the CCD camera are arranged, comprising an image processing unit that performs pattern matching between the actual tube holes and the master image captured (a reference image) with a CCD camera, the CCD mosquito
Arrange the lighting so that it is almost coaxial with the Mela,
To subtract the OFF image from the ON image
As a result, the image recognition of the tube hole is reduced due to the influence of the background and color.
It is characterized in that it can be prevented .

According to [0010] or mow invention, to eliminate the influence of the tube plate background and color, it is possible to accurate pattern matching.

[0011]

[0012]

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the embodiments shown in the drawings. However, unless otherwise specified, the dimensions, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention thereto, but are merely illustrative examples. FIG. 1 is a basic operation diagram showing an automatic pipe hole searching / welding procedure in a welding system in which a welding device 1 is mounted on an NC device 2 having a control personal computer PC in which a pipe hole automatic searching method is programmed. Specifically, a procedure for performing image recognition and seal welding of a tube hole provided in a tube sheet in a coordinated relationship among the control personal computer PC, the NC device 2, and the welding device 1 is schematically shown.

First, based on the program information obtained from the drawings, the assumed hole position information shifted by the following target hole pitch is added to the first assumed pipe hole position for seal welding or the pipe hole information at the previous stage at the time of seal welding. Communication is made from the control personal computer PC side to the NC device 2 side (T1), the CCD camera 3 provided in the NC device 2 which will be described later performs image recognition of the target tube hole 6, and the recognized image is sent to the control personal computer PC side. After the image processing (T2), the positional deviation from the assumed hole position is calculated (T3), the deviation amount is transmitted to the NC device 2 side (T4), and the deviation amount is calculated on the NC device 2 side. After performing the movement correction corresponding to (T5) and automatically positioning the pipe hole 6 and the welding device 1, the control personal computer PC monitors the welding position (T7) and seal welds the pipe hole 6 (T5).
Perform 6).

Then, in the pipe hole information of the previous stage at the time of seal welding,
The assumed hole position information shifted by the next target hole pitch is communicated from the control personal computer PC side to the NC device 2 side, and the above operation is repeated.

FIG. 2 is a block diagram of the automatic tube hole searching device used in the above system. In FIG. 2, an NC device 2 that is movable in three axial directions (Z, Y, Z ternary coordinate axes) of the tube sheet distance direction (Z axis) and the tube sheet surface direction (Χ, Y axis direction).
Is connected to the welding device 1 that is movable in parallel with the Z-axis, and the NC device 2 is provided with a CCD camera 3 that can move back and forth in the Z-axis direction, and an illumination 5 (for example, a ring-type illumination) coaxial with the CCD camera 3. Further, laser slit light sources 4 for emitting slit laser light are arranged in directions inclined by a predetermined angle with respect to the light receiving direction of the CCD camera 3.

As shown in FIG. 4, the illumination 5 is coaxially illuminated with respect to the CCD camera 3, and the laser slit light source 4 is predetermined so that the slit light is projected in the center (for example, the vertical direction) of the visual field range. The angle CCD camera 3 is arranged at a predetermined angle with respect to the light receiving direction (see FIG. 3A). As mentioned above, 1 is a welding device for performing seal welding, 2
Is an NC device for determining the position of the adjacent hole (position of the assumed hole) and correcting the position shift (movement by the shift amount), 9 is the control personal computer PC
The image processing apparatus incorporated in the above performs pattern matching between the reference image and the actual tube hole 6. Reference numeral 20 denotes a monitor incorporated in the control personal computer PC, which displays the pattern matching status of the image processing apparatus 9 and the like.

Next, an image processing procedure when performing height measurement using the above equipment will be described based on the principle diagram of FIG. N
Only one tube hole 6 (for example, the tube hole 6a at the left end of the uppermost stage shown in FIGS. 1 and 2) for first performing seal welding to the CCD camera 3 by the operator is reflected in the center of the visual field by the operator manually ( Position in the (narrow field) position. At this time, based on the resolution of the image of the CCD camera 3, the optimal CCD camera 3 and tube plate 7 are previously set.
Is set to the distance (reference distance) and the image of the limited range of the tube hole 6 and the slit light is registered in the image processing device 9 as the master image 8. At this time, the CCD camera 3 sets its field of view to a narrow field of view.

At the start of automatic operation, first, the height (front and rear) is measured (the distance between the CCD camera 3 and the tube sheet 7 is measured). First, as shown in the upper part of FIG. 3, since the CCD camera 3 and the laser slit light source 4 are arranged to be inclined by α with respect to the tube sheet 7, the tube sheet 7 is displaced forward and backward with respect to the reference distance. The position where the CCD camera 3 receives the laser slit light is displaced left and right in the figure. This is shown on the monitor 20 in the lower monitor diagram of FIG. That is, in the figure, when the tube sheet 7 is displaced forward, the slit light on the monitor 20 is shifted to the right with respect to the master image. Further, when the tube sheet 7 is displaced backward, the slit light on the monitor 20 is displaced leftward with respect to the master image.

Therefore, by using the fact that the position of the laser slit light in the field of view of the CCD camera 3 changes to the left and right in proportion to the change in the distance between the CCD camera 3 and the tube sheet 7, the amount of horizontal movement of the laser slit light is previously calculated. And the relationship between the front-back movement amount of the CCD camera 3 is obtained.

Next, image processing (pattern matching processing)
The image of the slit light portion which is the same as the master image 8 of the slit light portion is found by, and the amount of deviation between the position of the slit light in the master image 8 and the current position of the slit light in the image 10 is calculated by the CCD.
It is calculated as the amount of displacement (change in distance) before and after the camera 3.
At this time, filter processing is performed as necessary to increase the degree of recognition. This deviation amount is transmitted from the image processing device 9 to the control panel of the NC device 2 via the I / F (interface),
The displacement of the NC device 2 is corrected.

Alternatively, as shown in FIG. 1, positioning is roughly performed by the NC device 2 (proximity hole position, assumed hole position), and a three-axis moving mechanism for fine adjustment is separately provided to correct position deviation (deviation amount). You may move).

Up to this point, the operation of the NC device 2 will be mainly described with reference to the flowchart of FIG. First, the operator positions the NC device 2 at the program coordinates (X, Y, Z) of the start point. (S1) Next, the Z-axis (height direction) is lowered to position the NC device 2 at the image processing height position. (S2) Then, a height measurement instruction is issued from the NC device 2, the height (Z) is measured on the image processing device 9 side as shown in FIG. 3 (S3), and a measurement completion notification is transmitted to the NC device 2 side. After that (S4), the result code transmission request (S
In response to 5), the result code is transmitted from the image processing device 9 side. (S6)

Then, the NC device 2 determines whether the measurement result is normal or abnormal (S7), and if abnormal, suspends the measurement. If it is normal, a position data transmission request (S8, S1)
0), the Z upper data and the Z lower data are transmitted to the NC device 2 side (S9, S11), and the Z-axis height correction is performed based on the Z measurement data (S12). If it is within the range (S13), proceed to the next step.

Next, an image processing procedure when performing the positional deviation measurement (left and right, up and down) using the above device will be described based on the principle diagram of FIG. Based on the resolution of the image of the CCD camera 3, the optimum distance (reference distance) between the CCD camera 3 and the tube sheet 7 is set in advance, and the image of the tube hole is registered as the master image 8 in the image processing device 9. As described above. Next, with the field of view of the CCD camera 3 set to a narrow field of view,
An image of the same tube hole portion as the master image 8 of the tube hole portion is found by image processing (pattern matching processing), and the master image 8
The amount of deviation between the position of the hole in and the position of the tube hole in the current image 10 is calculated. At this time, filter processing is performed as necessary to increase the degree of recognition.

The amount of this deviation is transferred from the image processing device 9 to the I / F.
It is transmitted to the control panel of the NC device 2 via the (interface) to correct the deviation of the NC device 2. Then CCD
The NC device 2 is moved by an offset amount in the assembling distance between the camera 3 and the welding device 1, the welding device 1 is positioned at the target pipe hole position, and seal welding is performed. At this time, the pipe hole diameter is also obtained, and the flatness of the pipe, no hole, a screw hole (other than the target hole), etc. are determined.

In this case, in order to prevent the image recognition degree of the tube hole portion from being lowered due to the influence of the background and the color, the background 5 and the color are erased by turning on / off the illumination 5 and the laser slit light source 4.
It can be dealt with by the image. More specifically, by subtracting the OFF image from the image with the illumination 5 ON, the background image that is the background is not reflected (because no light hits the rear, the illumination 5 can be either ON or OFF). The background part disappears because the image is almost the same).
The laser slit light is also turned off from the image when the laser is turned on.
Only the laser light remains by subtracting the image, and the influence of the color can be excluded as well as the background.

Up to this point, the operation of the NC device 2 will be mainly described with reference to the flow chart of FIG. After the NC device 2 instructs the image processing device 9 to perform the displacement measurement (horizontal Χ, vertical Y) (S20), the displacement measurement (α, Y) is measured on the image processing device 9 side as shown in FIG. Perform (S2
1) After transmitting the measurement completion notification to the NC device 2 side (S2
2), request code transmission request from the NC device 2 side (S2
In response to 3), the result code is transmitted from the image processing device 9 side. (S24) Then, the NC device 2 side determines whether the measurement result is normal or abnormal (S25), and if abnormal, jumps to step (S31).

If normal, a position data transmission request (S2
6A, S26Y), the respective upper data and lower data of (I, Y) are transmitted to the NC device 2 side (S27,
S27Y), (Χ, Y) axis position correction is performed based on the Z measurement data (S28), and if the correction is within the error range, the assembly distance between the CCD camera 3 and the welding device 1 is NC by the offset amount. The device 2 is moved (S29), the welding device 1 is positioned at the target pipe hole position, and seal welding is performed (S30). After that, the process proceeds to the step of searching for the tube hole 6 of the next stage (adjacent, adjacent).

In the search step, first, a request for transmitting the operation method of the tube hole 6 in the next stage (adjacent, adjacent) is issued from the NC device 2 to the image processing device 9 (S31), and in response to this, the image processing device 9 side sends the request. The tube hole moving method is transmitted (S32), and the process proceeds to the step of FIG. 8 of the next stage search.

In FIG. 8, the Z axis is moved up to the next stage search position (S3
5), specifically, the CCD camera 3 is retracted, and more specifically, the field of view of the camera is retracted from a narrow field of view to a wide field of view to capture the plurality of tube holes 6. Incidentally, when the CCD camera 3 moves away from the narrow field of view to the wide field of view and the focus becomes uneasy and difficult to recognize, an autofocus lens, automatic lens exchange, etc. are provided. As an image, as shown in FIG. 5, the peripheral (upper, lower, left, and right) tube holes 6 around the target tube hole 6 in the narrow field of view are displayed. Similar to the recognition of the tube hole 6 in the narrow field of view by the pattern matching process, the tube hole 6 of the next stage (adjacent, adjacent) is found, and the movement amount (pitch) from the current position is obtained in the order of the Χ axis and the Y axis. , And transmits the respective data to the NC device 2. (S
36)

Then, the NC device 2 is moved and roughly positioned at the next position of the target tube hole 6. (S37) Next, after moving the CCD camera 3 forward in a narrow field of view, the NC device 2 side issues a next-stage hole search instruction (S38), whereby the positional deviation of the next-stage target tube hole 6 (Χ, Y). Is measured by the method shown in FIG. 4 (operations of (S20) to (S28)),
After performing the position correction operation (S39), the Z axis is raised to perform seal welding. (S40) Then, it is determined whether or not the pipe hole subjected to the seal welding is the final stage pipe hole. If the final stage is the final stage, the process ends. If not, the process proceeds to FIG.

When automatically searching for the adjacent or adjacent tube holes 6,
If the arrangement (horizontal direction) pitch of the tube holes 6 is constant and predetermined, the NC device 2 is moved by the designed pitch amount instead of the method of searching the tube holes 6 in the wide field of view described above. A method of recognizing the tube hole 6 and correcting the position by measuring the position shift in the narrow field may be used. When the tube holes 6 are not continuously provided, the image processing device 9 determines the number of rows and the number of rows of the tube holes 6.
Is registered (range designation) in advance, and when the target portion is reached, the movement amount for the range is automatically skipped. The same shall apply when not welding a certain step or row. Tube hole 6 at the end of the current step
In order to determine whether or not it is the end of the seal welding, the movement by the hole recognition described above is repeated with a narrow field of view, and it is recognized that the set number of hole pitches or the movement amount distribution pipe 6 does not exist. At that time, the last recognized tube hole 6 is determined to be the end, and the last recognized tube hole 6 is returned.

A method of searching for such a tube hole end will be described with reference to FIG. FIG. 5 shows a method of searching for the right-end tube holes when the tube holes 6 are arranged in a circular pattern in a disc-shaped tube sheet 7, and FIG. 5A shows the right-end tube above the center of the tube holes 6. A search method when the hole 6 is located is shown. As shown in FIG. 5 (A), the method for searching the end of the tube hole is as follows. First, the hole position 6a at the right end of the range that can be seen in the wide field of view is obtained, and then it is moved one pitch to the right, and as shown in When the position of the hole 6b at the right end of the lower right visible range is at the same pitch position as the previously determined tube hole 6a (position in the x direction = position obtained previously-1 pitch), it is determined to be the right end. If not,
Further, shifting by one pitch is repeated to obtain the right end tube hole position.

FIG. 5B shows a search method when the right end tube hole 6a is located below the center of the tube hole 6. From the center of the tube sheet 7 to the lower side, the number of holes decreases conversely, so a hole comes diagonally to the lower left. Therefore, as shown in (B), the hole position 6a at the right end of the visible range in the wide field of view is first obtained, and then 1
Move to the left by the pitch, in this case, if no holes are found in the lower row as shown in, add n pitches (n pitch =
(In case of hole pitch visible in the field of view, n = 2 pitch in case of)
This is repeated until the hole 6b is obtained by moving to the left.

Since the upper side and the lower side of the center of the tube sheet 7 cannot be recognized in this example, it is confirmed in this example that the pitch is not moved to the right, and then the pitch is moved to the left. Will move. The search method is a search method in the case where the tube hole 6 is at the right end, but the search method for the portion where the tube hole 6 is at the left end of the tube sheet 7 is also performed in the same way as the above in the procedure of left-right reversal in FIG.

Therefore, the method for searching the end of the tube hole is as follows.
When moving from the next stage to the next stage, first, in order to search for the tube hole 6 at the end, in the same direction as the traveling direction in the previous stage, the above-mentioned movement by the hole recognition in the narrow field is repeated, and the set number of hole pitch times,
Alternatively, when it is recognized that there is no moving amount distribution hole 6, the last recognized hole 6 is determined to be the end, and the last recognized hole 6 is detected.
Return to. Then, the above hole recognition, positioning, and seal welding are repeated from the obtained end hole in the direction opposite to the traveling direction in the preceding stage, and thereafter, the same procedure is performed up to the final tube hole 6.

If the pipe hole 6 is not found within the preset allowable number of pitch movements in the end hole search for the next step, the current step is determined to be the final step. However, the portion without continuous holes which has been input in advance skips and continues pitch movement. The total number of stages may be registered in the image processing apparatus 9 and the final stage may be determined by the stage number management.

In addition, if repair is required after seal welding,
The position after recognition and correction of each tube hole 6 is registered and managed in the image processing device 9 for all the tube holes 6, and an error is taken into consideration when re-recognizing and positioning the target tube hole position for repair. If it is within the error range, it is judged as the registered tube hole 6. If you want to stop in the middle of a certain stage and continue from that stage again, judge the traveling direction by the first odd / even stage instruction at the start hole position, or support the traveling direction for automatic operation. Let it start.

[0040]

As described above, according to the present invention, it is not necessary to create a program with an NC tape for each tube sheet, and by eliminating the NC tape, man-hours and costs can be reduced. Further, by performing non-contact and highly accurate positioning by image processing, a center rod or the like for centering the welding device can be eliminated. Furthermore, the aiming position of the welding device becomes appropriate by performing highly accurate three-dimensional positioning, and quality can be improved, and unattended operation is possible by performing highly accurate positioning and monitoring the target position of the welding device. Can be planned. Further, by separately providing a CCD camera, it is possible to monitor the welding situation, detect the position of the filler wire and the tungsten electrode of the welding device, and detect any abnormal shape.

[Brief description of drawings]

FIG. 1 shows an overall schematic diagram of a pipe hole automatic search method.

FIG. 2 shows a device configuration diagram in a pipe hole automatic search method.

FIG. 3 shows a principle diagram of image processing (height measurement) in the tube hole automatic search method.

FIG. 4 shows a principle diagram of image processing (positional deviation measurement) in the tube hole automatic search method.

FIG. 5 shows a method of searching for the right end tube holes when the tube holes are arranged in a circular pattern in a disc tube plate in a circular pattern, and (A) shows that the right end tube holes are located above the center of the tube holes. (B) shows the search method in the case where the right end tube hole is located below the center of the tube hole.

FIG. 6 to FIG. 8 are process flowchart diagrams in the tube hole automatic searching method, and FIG. 6 is a flowchart diagram showing a position correction procedure in the Z-axis (height direction) direction.

FIG. 7 is a flowchart showing a procedure for position correction in the (horizontal axis, vertical Y axis) direction.

FIG. 8 is a flowchart showing a procedure for correcting the position (Χ, Y) with respect to the next target tube hole.

[Explanation of symbols]

1 welding equipment 2 NC device 3 CCD camera 4 Laser slit light source 5 lighting 6 tube holes 7 tube sheet 8 master images 9 Image processing device 10 current image

─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Takehisa Hasegawa 1-1-1, Wadasaki-cho, Hyogo-ku, Kobe Mitsubishi Heavy Industries, Ltd. Kobe Shipyard (56) Reference JP-A-9-1338 (JP, A) JP 59-218279 (JP, A) JP 62-174609 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01B 11/00 B23K 9/028 B23K 9/127 508 B23K 37/053

Claims (2)

(57) [Claims] 1. A tube plate having a large number of tube holes, each tube being controlled while moving a triaxial NC device in a tube plate distance direction (Z axis) and a tube plate surface direction (Χ, Y axis direction). In the automatic tube hole position search method for sequentially searching for holes, an NC device equipped with a CCD camera capable of selecting a narrow field of view or a wide field of view of the camera, an actual tube hole captured by the CCD camera, and a master image (reference image) The image processing unit that performs pattern matching with
By using the optimal distance between the CCD camera and the tube plate surface (reference distance) in advance, register the image of the tube hole as a master image in the image processing device, and switch the field of view of the CCD camera to a wide field of view. The CCD power
Multiple pattern holes can be captured with Mera for pattern matching processing
Find the next (neighboring, adjacent) tube hole and the current target tube hole position
The amount of movement from the position is calculated, and the NC device is located based on the amount of movement.
After moving the fixed pitch, the field of view of the CCD camera is switched to a narrow field of view, the amount of deviation between the master image and the position of the actually imaged target tube hole is obtained by the pattern matching processing of the image processing unit, and based on the amount of deviation. A pipe hole position automatic searching method, characterized in that a deviation of an NC device with respect to a target pipe hole is corrected. 2. A tube sheet having a large number of tube holes, each tube being controlled while moving a triaxial NC device in a tube sheet distance direction (Z axis) and a tube sheet surface direction (Χ, Y axis direction). In an automatic tube hole position searching apparatus for sequentially searching for holes, a CCD camera capable of selecting a narrow field of view or a wide field of view of a camera, and a laser light source for emitting a slit laser in a direction inclined at a predetermined angle with respect to a light receiving direction of the CCD camera And an image processing unit that performs pattern matching between the actual tube hole imaged by the CCD camera and the master image (reference image), so that the CCD camera is substantially coaxially illuminated. Teru
Image where light is placed and the light is turned off from the image turned on
Image of the tube hole due to the influence of the background and color
An automatic pipe hole position searching device, characterized in that it is configured to prevent a decrease in recognition .