JP2019084551A - Seam tracking system and metal product manufacturing method - Google Patents

Abstract

To provide a seam tracking system which can determine a weld line more easily while suppressing reduction in detection accuracy of a weld line due to false detection.SOLUTION: The seam tracking system comprises: a one side detection part 41 which is positioned on most one side on a prescribed scan line of imaging data, and detects one side presumption point which is presumed as a weld line S; an other side detection part 42 which is positioned on most other side on the scan line, and detects other side presumption point which is presumed as a weld line S; an approximate line calculation part 43 which calculates an approximate straight line or an approximate curve based on one side presumption point and other side presumption point which are detected on plural scan lines; and a position control part 44 which controls a weld position of a welding head 3 so as to set the approximate straight line or the approximate curve to the weld line S and perform welding on the weld line S. The approximate line calculation part 43 calculates an approximate straight line or an approximate curve except for one side presumption point and other side presumption point between which a clearance on a same scan line is a prescribed threshold or more.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a seam tracking system and a metal product manufacturing method for welding using an image sensor.

  The seam tracking system is an automatic welding system that detects a weld line (seam line) by an image sensor preceding a weld head and controls the position of the weld head on the weld line. In this seam tracking system, since the welding quality is affected by the detection accuracy of the weld line by the image sensor, it is required to improve the detection accuracy of the weld line. The detection of the weld line is described, for example, in Japanese Patent Application Laid-Open Nos. 9-201673 and 10-193148. In these techniques, an approximate straight line is calculated from a plurality of detection points, and a detection point separated from the calculated approximate straight line by a predetermined distance or more is processed as an erroneous detection.

JP 9-201673 A Unexamined-Japanese-Patent No. 10-193148

  However, in the above technology, after calculating the approximate straight line, it is determined whether or not it is a false detection, and if there is a false detection, the approximate straight line must be calculated again except for the false detection point. In other words, after collecting detection point data for which the approximate straight line can be calculated once, correction processing of the approximate straight line must be repeated. As a result, the calculation becomes complicated including feedback, and there is a possibility that the calculation and setting of the approximate straight line may be delayed. In addition, it is not possible to determine whether the detection point is a false detection point until the approximate straight line is calculated.

  The present invention has been made in view of such circumstances, and a seam tracking system and a metal product which can more easily determine a weld line while suppressing a decrease in detection accuracy of the weld line due to false detection The purpose is to provide a manufacturing method.

  The seam tracking system according to the present invention comprises an image sensor for imaging a workpiece while advancing in a predetermined advancing direction, a welding head for following the image sensor, and a weld line of the workpiece based on imaging data captured by the image sensor. And a controller for detecting a welding position of the welding head based on the welding line, wherein the controller is an imaginary straight line extending in a direction orthogonal to the traveling direction in the imaging data. Assuming that the scanning line is a scanning line, a one-side detection unit for detecting the one-side estimation point estimated to be the welding line, which is located on the most one side of the predetermined scanning line of the imaging data; The other side detection unit for detecting the other side estimation point estimated to be the weld line, and the one side detected on a plurality of the scanning lines The welding is performed by setting the approximate straight line or the approximate curve on the welding line, and calculating the approximate straight line or the approximate curve on the basis of the fixed point and the other side estimation point, and setting the welding line along the welding line. And a position control unit for controlling the welding position of the head, wherein the approximate line calculation unit excludes the one-side estimation point and the other-side estimation point whose separation distance on the same scanning line is equal to or greater than a predetermined threshold. And calculating the approximate straight line or the approximate curve.

  In the metal product manufacturing method of the present invention, an image sensor for imaging a metal work while advancing in a predetermined traveling direction, a welding head for following the image sensor, and imaging data captured by the image sensor A control device for detecting a welding line of the workpiece and controlling a welding position of the welding head based on the welding line, the metal product manufacturing method using a seam tracking system, wherein the imaging data Assuming that a virtual straight line extending in a direction orthogonal to the traveling direction is a scanning line, the control device detects the one-side estimation point presumed to be the welding line, which is located closest to one side on the scanning line of the imaging data. One side detection step, and the other side detection step for detecting the other side estimation point presumed to be the welding line, which is located on the other side on the scanning line, An approximation line calculating step of calculating an approximation straight line or an approximation curve based on the one-side estimation point and the other-side estimation point detected on the plurality of scanning lines, and the approximation line or the approximation curve Setting the welding line to the welding line, and controlling the welding position of the welding head so as to weld the welding line, and in the approximation line calculation process, the separation distance on the same scanning line is predetermined The approximate straight line or the approximate curve is calculated except for the one-side estimation point and the other-side estimation point that are equal to or greater than a threshold.

  According to the present invention, calculation of the approximate straight line or the approximate curve is performed because it is possible to determine whether or not the calculation element of the approximate straight line or the approximate curve is based on the magnitude of the separation distance (shift) between the one side estimation point and the other side estimation point. False detection can be determined regardless of before or after. That is, it is not necessary to calculate an approximate straight line or an approximate curve in advance for the determination of an erroneous detection. This makes it possible to calculate (set) weld lines easily (rapidly). In addition, when the separation distance between the two estimation points on the scanning line is large, there is a high possibility that at least one estimation point is a false detection due to a scratch or a shadow of the work, and the welding line is detected by excluding it from the computing element. Accuracy is maintained or improved. As described above, according to the present invention, it is possible to more easily determine the weld line while suppressing the decrease in the detection accuracy of the weld line due to the erroneous detection.

It is a block diagram of the seam tracking system of this embodiment. It is a conceptual diagram of the imaging data of the image sensor of this embodiment. It is a conceptual diagram of the approximation straight line of this embodiment. It is a flowchart which shows the flow of the process of this embodiment. It is a schematic cross section of the object work which has a sag. It is a conceptual diagram of the imaging data of the image sensor in the modification of this embodiment.

  Hereinafter, an embodiment of the present invention will be described based on the drawings. Each figure used for explanation is a conceptual diagram, and the shape of each part is not necessarily exact. As shown in FIG. 1, the seam tracking system 1 according to the present embodiment includes an image sensor 2, a welding head 3, and a control device 4. The image sensor 2 is an apparatus for imaging the target work W while advancing in a predetermined traveling direction in order to detect a weld line (seam line) S of the target work W. The target work W of the present embodiment is composed of two metal plate-like works W1 and W2 which are butted to each other. The welding line S is a line formed by bringing the end of the first work W1 into contact with the end of the second work W2. The butt portion is also referred to as a groove. In the description, the surface of the target work W facing the welding head 3, that is, the surface on which the welding line S of the target work W is exposed is taken as the surface of the target work W.

  The image sensor 2 is disposed apart from the surface of the target work W, and is configured to be movable in a predetermined traveling direction. The image sensor 2 includes a camera 21 and a light source 22. The camera 21 is, for example, a CCD camera, and is disposed to face the surface of the target workpiece W. The camera 21 captures an image of the surface of the target work W and transmits the captured data to the control device 4. The light source 22 is a device that emits light to the target work W for imaging.

  The image sensor 2 is set to image the target work W at each predetermined moving distance. As shown in FIG. 2, in the present embodiment, a virtual straight line extending in a direction orthogonal to the traveling direction of the image sensor 2 in imaging data is taken as a scanning line. Further, in the description of the present embodiment, the advancing direction is referred to as “front-rear direction”, and the direction orthogonal to the advancing direction and parallel to the extending direction (surface) of the target work W is referred to as “left-right direction”. The camera 21 is disposed such that the horizontal scanning direction is in the left-right direction.

  The welding head 3 is an apparatus for welding a workpiece, and is configured to follow the movement of the image sensor 2. That is, the welding head 3 is disposed behind the image sensor 2 and advances (integrally) in conjunction with the advancement of the image sensor 2. The image sensor 2 and the welding head 3 are set to advance at a predetermined speed, for example. The welding head 3 is, for example, a welding torch that emits a laser beam, and is disposed to face the welding line S of the target work W. The welding head 3 welds the welding line S of the target work W as a welding target while advancing. The welding head 3 is configured to be movable also in the left-right direction in accordance with the control of the control device 4 in order to correspond to the deviation between the welding line S and the welding position. The image sensor 2 and the welding head 3 of the present embodiment constitute a part of a laser welding apparatus (for example, a welding apparatus including a robot arm) A. In other words, the laser welding apparatus A includes the image sensor 2 and the welding head 3. Further, in the welding preparation stage, the target work W is arranged with respect to the laser welding apparatus A so that the welding line S visually matches with a planned traveling path (a straight line extending in the front-rear direction) of the welding head 3.

  The control device 4 is a computer (for example, a personal computer) connected to the laser welding apparatus A and provided with a CPU, a memory, and the like. The control device 4 detects the welding line S based on the imaging data captured by the image sensor 2 and controls the welding position of the welding head 3 based on the welding line S. That is, the control device 4 moves the welding position (welding target position) of the welding head 3 to the left and right according to the detected welding line S while moving the image sensor 2 and the welding head 3 forward.

  The control device 4 includes, as functions, one side detection unit 41, the other side detection unit 42, an approximate line calculation unit 43, and a position control unit 44. The one-side detection unit 41 is configured to detect a one-side estimation point estimated to be a weld line S, which is located on the most one side of a predetermined scanning line of imaging data. In other words, the one side detection unit 41 analyzes a predetermined scanning line of imaging data from one end to the other end, and detects a point / position presumed to be a weld line S (one side estimation point) . It can be said that the one-side detection unit 41 analyzes an image of a predetermined scanning line in one direction (right direction) and detects the position of the other end (right end) of the one-side work W1 of the target work W.

  More specifically, as shown in FIG. 2, the one-side detection unit 41 executes image processing on the imaging data, and the brightness located at the most one side (left side) on the scanning line is less than the predetermined value Dark point is detected, and that point is set as one-side estimation point. The one-side detection unit 41 executes image processing from the imaging data from one end to the other end on the scanning line, and detects a point whose brightness is less than a predetermined value, and sets that point as one-side estimation point Do. The one side detection unit 41 transmits the position information (coordinate information) of the one side estimation point to the approximate line calculation unit 43. The position information can be recorded at (X, Y) coordinates, for example, with the left and right direction as the X axis direction and the front and back direction as the Y axis direction. The position information may be three-dimensional coordinate information (X, Y, Z) in which the vertical direction is added as the Z-axis direction.

  The other side detection unit 42 is configured to detect the other side estimated point estimated to be the weld line S, which is located on the other side of the predetermined scanning line of the imaging data. In other words, the other side detection unit 42 analyzes a predetermined scanning line of the imaging data from the other end toward the one end, and detects a point / position presumed to be the weld line S (the other side estimation point) . It can be said that the other side detection unit 42 analyzes an image of a predetermined scanning line in the other direction (left direction) and detects the position of one end (left end) of the other side work W2 of the target work W.

  More specifically, the other side detection unit 42 performs image processing on the imaging data, and detects a point (dark point) whose brightness on the other side (right side) on the scanning line is less than a predetermined value, The point is set to the other side estimation point. The other side detection unit 42 executes image processing from the other end to the one end of the scanning line and detects a point whose brightness is less than a predetermined value, and sets that point as the other side estimation point Do. The other side detection unit 42 transmits the position information (coordinate information) of the other side estimation point to the approximate line calculation unit 43.

  The one-side detection unit 41 and the other-side detection unit 42 can simultaneously detect the estimated points by common image processing on the imaging data. The predetermined scanning line is a straight line passing a predetermined point (predetermined coordinate) of the imaging data, and one or a plurality of scanning lines are set in one imaging data. In the present embodiment, one predetermined scanning line (analysis position) is set for one piece of imaging data.

  The approximate line calculation unit 43 is configured to calculate an approximate straight line based on the one-side estimation point and the other-side estimation point on the plurality of scanning lines. The approximate line calculation unit 43 records both estimation points with one set of estimation points on one side and the estimation point on the other side acquired on one (identical) scanning line. The approximate line calculation unit 43 calculates the separation distance between the one-side estimation point and the other-side estimation point detected on the same scanning line. That is, the approximate line calculation unit 43 calculates, for each set, the difference (absolute value) between the X coordinate of the one-side estimation point and the X coordinate of the other-side estimation point. The approximate line calculation unit 43 determines whether the separation distance (i.e., the difference) is equal to or greater than a predetermined threshold. Ideally, the one-side estimation point and the other-side estimation point coincide with each other, and the difference (deviation) is zero.

  As shown in FIG. 3, the approximate line calculation unit 43 calculates an approximate straight line except for a set (one-side estimation point and the other-side estimation point) in which the separation distance on the scanning line is equal to or larger than a predetermined threshold. In other words, the approximate line calculation unit 43 calculates the approximate straight line using only the set whose separation distance is less than the predetermined threshold. In the calculation of the approximate straight line, for example, when the one side estimation point and the other side estimation point are at the same position (coordinates), the one point is used as the estimation point of the set, and the positions of both estimation points are different The distance may be smaller than a predetermined threshold) by using an intermediate point (intermediate coordinate) of the one-side estimation point and the other-side estimation point as the estimation point of the set. The black circles in FIG. 3 indicate the one-side estimation point and the other-side estimation point (that is, the coincidence point) where the separation distance is zero, or the middle point between the one-side estimation point and the other-side estimation point whose separation distance is less than a predetermined threshold. Indicates Further, white circles in FIG. 3 indicate one-side estimation points and the other-side estimation points at which the separation distance is equal to or more than a predetermined threshold value.

  The approximate line calculation unit 43 excludes a set whose separation distance is equal to or more than a predetermined threshold as an erroneous detection set (two erroneous detection points) from the calculation of the approximate straight line. After calculating the approximate straight line, the approximate line calculation unit 43 moves (offsets) the excluded erroneous detection point on the approximate straight line. The black diamonds in FIG. 3 indicate estimated points after offset. In addition, the broken line in FIG. 3 shows the boundary of the area | region (normal determination area | region) whose separation distance is less than a predetermined threshold-value on the basis of the approximation straight line of the other side presumed point as an example. This is an idea in the case where it is considered that the estimation accuracy (end portion detection accuracy) of the other-side estimated point is high, for example, when only the abutting portion of the other workpiece W2 is in the vertical plane (see FIG. 5). In this case, it is possible to set a normal judgment area (an area sandwiched by broken lines) based on the other side estimated point. In this case, for example, when the one-side estimation point is detected outside this area (above the upper broken line), it is determined as a false detection, and the estimation point is excluded from the calculation element. However, the broken line in FIG. 3 is an example different from the present embodiment, and in the present embodiment, it is erroneously detected or not by comparing the separation distance between the one side estimation point and the other side estimation point and a predetermined threshold value. Is determined.

  The approximate line calculation unit 43 calculates an approximate straight line based on a predetermined number of estimated point sets, and the estimated point set whose separated distance is less than a predetermined threshold value also approximates the estimated points for the estimated point set acquired thereafter. The approximate straight line is updated for each predetermined number in addition to the computing elements in the above, and the estimated point set whose separation distance is equal to or larger than the predetermined threshold moves the erroneous detection point on the approximate straight line.

  As described above, the approximate line calculation unit 43 determines whether or not the separation distance between the one side estimation point and the other side estimation point on the same scanning line is less than (or more than) a predetermined threshold, and the separation distance Is a calculation unit that calculates an approximate straight line using only one side estimation point and the other side estimation point, which is less than a predetermined threshold value, and in a state where the approximate straight line is calculated (set), It can be said that an offset unit for moving the estimation point and the other-side estimation point on an approximate straight line is provided.

  The predetermined threshold is set in advance based on at least one of the groove shape and the difference in the thickness of the two workpieces W1 and W2 which are abutted with each other by experiment, simulation or the like. For example, when the groove shape of at least one of the works W1 and W2 is a curved shape having a sag, compared to the situation in which the groove shapes are perpendicular to each other, shadows are easily generated in the imaging data, and one side estimation point It is considered that the deviation (separation distance) from the other side estimation point tends to be large. Similarly, for example, when the thickness (plate thickness) of the works W1 and W2 is different, a shadow is easily formed in the imaging data as compared with the situation where the thickness is the same, and one side estimation point and the other side estimation point It is considered that the deviation tends to be large. As described above, the predetermined threshold can be set in advance according to the states of the works W1 and W2.

  The position control unit 44 is configured to set the approximate straight line as the welding line S and to control the welding position of the welding head 3 so as to weld the set welding line S. The position control unit 44 adjusts the left and right positions of the welding head 3 so that the welding position passes through the coordinates on the approximate straight line as the welding head 3 advances. The welding head 3 moves to the left and right according to a command from the position control unit 44. The position control unit 44 controls the left and right positions of the welding head 3 while the left and right positions of the image sensor 2 are fixed while the image sensor 2 and the welding head 3 are advancing or stopping. Basically, the image sensor 2 and the welding head 3 integrally advance without changing the separation distance in the front-rear direction (Y-axis direction).

  This embodiment can also be described as a method of manufacturing a metal product. That is, the metal product manufacturing method of the present embodiment is a method of manufacturing a metal product by welding a work using the seam tracking system 1, and as shown in FIG. One-side detection step S101 for detecting one-side estimated point presumed to be welding line S located on the most one side on a predetermined scanning line, and welding line where control device 4 is located on the other other side on the scanning line The other side detection step S102 for detecting the other side estimation point estimated to be S, and the control device 4 calculate an approximate straight line based on the one side estimation point and the other side estimation point detected in a plurality of scanning lines. In the approximate line calculation step S103, an approximate line calculation step S103, and a position control step S104 in which the approximate straight line is set to the welding line S and the welding position of the welding head 3 is controlled to weld on the welding line S , Device 4, the distance on the same scan line with the exception of one side estimate point and the other side estimate point is above a predetermined threshold value, and calculates an approximate straight line.

  Here, in the approximate line calculation step S103, the control device 4 calculates the separation distance between the one-side estimation point and the other-side estimation point on the same scanning line, and determines whether the separation distance is less than a predetermined threshold. The determining step S1031 and the calculating step S1032 in which the control device 4 calculates the approximate straight line using only the one-side estimation point and the other-side estimation point whose separation distance is less than the predetermined threshold value are included.

  When the separation distance between the detected one-side estimation point and the other-side estimation point is less than the predetermined threshold (S1031: Yes), the control device 4 sets the estimation point as a calculation element used in calculation of the approximate straight line S1032). When acquiring a predetermined number of operation elements, the control device 4 calculates an approximate straight line (S1032). On the other hand, when the separation distance between the detected one-side estimation point and the other-side estimation point is not less than the predetermined threshold (S1031: No), the estimation point is not set as a point used in the calculation of the approximate straight line and excluded from the calculation element (S1033). Here, when the approximate straight line has already been calculated, the control device 4 offsets the estimated point to be excluded from the calculation element onto the approximate straight line (S1033). That is, when the separation distance between the detected one-side estimation point and the other-side estimation point is not less than a predetermined threshold when the approximate straight line is calculated, the control device 4 approximates the two estimation points. It includes an offset step S1033 of moving on a straight line. For example, the flow of such processing is performed for each scanning line (for each imaging data in the present embodiment). Steps S101 and S102 may be performed simultaneously. Through the welding, metal products (for example, parts for vehicles) are manufactured.

  According to the present embodiment, since the propriety of the operation element of the approximate straight line is determined based on the magnitude of the separation distance (shift) between the one-side estimation point and the other-side estimation point Detection can be determined. That is, it is not necessary to calculate an approximate straight line in advance for the determination of the erroneous detection, and for example, the erroneous detection can be determined every time the estimation point is detected. This makes it possible to calculate (set) weld lines easily (rapidly).

  In addition, when the separation distance between the two estimation points on the scanning line is large, there is a high possibility that at least one estimation point is an erroneous detection due to a flaw or a shadow of the workpiece W1 or W2. Line detection accuracy is maintained or improved. In addition, erroneous detection caused by variations due to repeated detection of the image sensor 2 itself can be excluded from the calculation elements. As described above, according to the present invention, it is possible to more easily determine a weld line while suppressing a decrease in detection accuracy (tracking accuracy) of a weld line due to an erroneous detection.

  Further, by offsetting the erroneously detected estimated point on the approximate straight line, while leaving the fact that the estimated point is detected for the scanning line (for example, while preventing the error recognition such as undetected by the control device 4) It can be suppressed that it interferes with the later calculation of the approximate straight line. The control device 4 may be configured to delete an erroneously detected estimated point or to recognize it as an erroneous detection point.

  In addition, the predetermined threshold value is determined based on at least one of the groove shape and the difference between the thicknesses of the two workpieces that are abutted, thereby further depending on the state of the target workpiece W and the combination of the two workpieces W1 and W2. Welding becomes possible. For example, as shown in FIG. 5, when a sagging is formed at the butt portion of one work W1 (and / or when the thicknesses are different from each other), the predetermined threshold is taken into consideration in consideration of the shadow produced by the sagging or the like. By setting, it is possible to detect the welding line S with high accuracy according to the state of the target work W.

(Others)
The present invention is not limited to the above embodiment. For example, the approximate line calculation unit 43 may be set to calculate an approximate curve. Further, detection of an estimation point is detected by image processing (detection processing) in which one side estimation point is directed from one end of the imaging data to the other end as in the above embodiment, and the other side estimation point is the other end of imaging data Although it is efficient to detect by image processing directed from one end to the other, it may be performed by other methods. Further, a plurality of scanning lines (also referred to as detection lines) may be set in one imaging data. Also, each estimated point can be said to be a detection point.

  Further, in the control device 4, in addition to the predetermined threshold value, one side limit value (upper limit value) and the other side limit value (lower limit value) may be set in the X coordinate. In this case, for example, when the at least one of the one-side estimation point and the other-side estimation point is on one side of the one-side limit value, the approximation line calculation unit 43 or at least one of the one-side estimation point and the other side estimation point When is on the other side of the other side limit value, both of the estimated points may be excluded from the calculation elements of the approximate straight line regardless of the magnitude of the separation distance. Also, these estimated points may be offset on an approximate straight line. By adopting such a configuration, it is possible to omit the calculation of the separation distance when there is a clear misdetection. In addition, estimated points that are less than the predetermined threshold but are both outside the limit value can also be excluded from the calculation element. That is, reduction in accuracy can be further suppressed.

  Moreover, the setting of the operation element (estimated point) of the approximate straight line is not limited to the above embodiment. For example, instead of using the middle point between the one-side estimation point and the other-side estimation point as the calculation element of the approximate straight line, the estimation point on the side where the calculation element of the approximate straight line is preset (one-side estimation point or other side estimation The operation element of the approximate straight line may be determined after weighting so as to be closer to the point). For example, as shown in FIG. 5 and FIG. 6, when there is a sag only at the butt portion of one work W1, there is a high possibility that only one side estimated point is detected away from the actual welding line S by the sag. . In such a case, of the one-side estimation point and the other-side estimation point at which the separation distance is less than the predetermined threshold value, using only the other-side estimation point or using a point closer to the other-side estimation point than the middle point An approximate straight line may be calculated. Thereby, determination of welding line S according to the state and combination of object work W is attained. The weighting can be determined based on, for example, the groove shape and the thickness difference of the workpieces W1 and W2 by experiments or the like. If a plurality of operation elements are set, calculation of the approximate straight line or approximate curve can be performed by a known method.

DESCRIPTION OF SYMBOLS 1 ... Seam tracking system, 2 ... Image sensor, 21 ... Camera, 22 ... Light source, 3 ... Welding head, 4 ... Control device, 41 ... One side detection part 42 ... Other side detection part 43 ... Approximate line calculation part, 44: Position control unit, W: Target work, W1, W2: Work.

In the seam tracking system according to the present invention, an image sensor for imaging a workpiece while advancing in a predetermined advancing direction, a welding head for following the image sensor, and a butt portion of the workpiece based on imaging data imaged by the image sensor to detect the weld line to be welded appearing as a shadow, a seam tracking system and a control device for controlling the welding position of the welding head on the basis of the weld line, the control device, the imaging data Assuming that a virtual straight line extending in a direction orthogonal to the traveling direction is a scanning line, and the welding line is estimated to be located closest to one of the predetermined scanning lines of the imaging data based on the brightness of the imaging data while a side detection unit, based on the brightness of the imaging data, the most other side of the scanning line to detect the one-side estimate point to be An approximate straight line or an approximate straight line based on the one side estimation point and the other side estimation point detected on a plurality of the scanning lines, and the other side detection unit that detects the other side estimation point estimated to be the weld line located An approximate line calculation unit that calculates an approximate curve, and a position control unit that sets the approximate straight line or the approximate curve to the welding line and controls the welding position of the welding head so as to weld on the welding line. The approximate line calculation unit calculates the approximate straight line or the approximate curve except for the one-side estimation point and the other-side estimation point whose separation distance on the same scanning line is a predetermined threshold or more.

In the metal product manufacturing method of the present invention, an image sensor for imaging a metal work while advancing in a predetermined traveling direction, a welding head for following the image sensor, and imaging data captured by the image sensor Control apparatus for detecting a weld line to be welded which appears as a shadow on the butt portion of the work, and controlling a welding position of the welding head based on the weld line; and manufacturing a metal product using a seam tracking system In the method, assuming that a virtual straight line extending in a direction orthogonal to the traveling direction in the imaging data is a scanning line, the control device determines the most on the scanning line of the imaging data based on the brightness of the imaging data. on the other hand located on the side, and one side detection step of detecting a one-side estimate point that is estimated to the weld line, wherein the controller, light of the imaging data Based on the located most other side of the scanning line, and the other side detection step of detecting the other side estimated point that is estimated to the weld line, the control device has been detected by the plurality of the scan lines An approximation line calculating step of calculating an approximation straight line or an approximation curve based on the one side estimation point and the other side estimation point, setting the approximation line or the approximation curve as the welding line, and welding the welding line And a position control step of controlling the welding position of the welding head, and in the approximate line calculation step, the one-side estimation point and the other-side estimation whose separated distance on the same scanning line is equal to or more than a predetermined threshold With the exception of points, the approximate straight line or the approximate curve is calculated.

Claims (8)

An image sensor for imaging a workpiece while advancing in a predetermined advancing direction, a welding head for following the image sensor, and a welding line of the workpiece are detected based on imaging data imaged by the image sensor, and A controller for controlling a welding position of the welding head based on the seam tracking system.
The controller is
Assuming that a virtual straight line extending in a direction orthogonal to the traveling direction in the imaging data is a scanning line, the one-side estimation point estimated to be the welding line located on the most one side of the predetermined scanning line of the imaging data One side detection unit to detect,
The other side detection unit which detects the other side estimation point estimated to be the welding line, which is located on the other side of the scanning line;
An approximate line calculation unit that calculates an approximate straight line or an approximate curve based on the one-side estimation point and the other-side estimation point detected on a plurality of the scanning lines;
A position control unit that sets the approximate straight line or the approximate curve to the welding line, and controls a welding position of the welding head so as to weld on the welding line;
Equipped with
The seam tracking system, wherein the approximate line calculation unit calculates the approximate straight line or the approximate curve except for the one-side estimation point and the other-side estimation point whose separation distance on the same scanning line is equal to or more than a predetermined threshold.   The approximate line calculation unit, when the approximate straight line or the approximate curve is calculated, indicates position information of the one-side estimation point and the other-side estimation point whose separation distance on the same scanning line is equal to or more than the predetermined threshold. The seam tracking system according to claim 1, wherein the line is moved on the approximate straight line or the approximate curve.   The seam tracking system according to claim 1 or 2, wherein the predetermined threshold is preset based on at least one of a groove shape and a difference in thickness of the two workpieces which are abutted.   When the at least one of the one-side estimation point and the other-side estimation point on the same scanning line is on one side of the one-side limit value, or the approximate line calculation unit is used, or the one-side estimation point and the other side When at least one of the estimated points is on the other side of the other side limit value, the approximate straight line or the approximate curve is calculated excluding the two estimated points regardless of the magnitude of the separation distance. Seam tracking system according to any one of the preceding claims. An image sensor for imaging a metal work while advancing in a predetermined advancing direction, a welding head for following the image sensor, and a welding line of the work detected based on imaging data imaged by the image sensor; A control device for controlling a welding position of the welding head based on a welding line, and a metal product manufacturing method using a seam tracking system,
Assuming that a virtual straight line extending in a direction orthogonal to the traveling direction in the imaging data is a scanning line,
A one-side detection step of detecting the one-side estimation point estimated to be the weld line, the control device being positioned on the most one side of the scanning line of the imaging data;
The other side detection step of detecting the other side estimation point estimated to be the welding line, which is located on the most other side of the scanning line;
An approximation line calculation step of calculating an approximation straight line or an approximation curve based on the one-side estimation point and the other-side estimation point detected on a plurality of the scanning lines by the control device;
A position control step of setting the approximate straight line or the approximate curve to the welding line and controlling a welding position of the welding head so as to weld on the welding line;
Including
In the approximate line calculation step, the control device calculates the approximate straight line or the approximate curve except for the one-side estimation point and the other-side estimation point whose separation distance on the same scanning line is a predetermined threshold or more. Metal product manufacturing method.   In the approximate line calculation step, in a state where the approximate straight line or the approximate curve is calculated, the control device determines the one side estimated point and the other side where the separation distance on the same scanning line is equal to or more than the predetermined threshold The metal product manufacturing method according to claim 5, wherein position information of the estimated point is moved on the approximate straight line or the approximate curve.   The metal product manufacturing method according to claim 5 or 6, wherein the predetermined threshold value is preset based on at least one of a groove shape and a difference in thickness of the two workpieces which are abutted.   In the approximate line calculation step, when at least one of the one-side estimation point and the other-side estimation point on the same scanning line is on one side of the one-side limit value, or the one-side estimation point and the other side When at least one of the estimated points is on the other side of the other side limit value, the control device calculates the approximate straight line or the approximate curve excluding both the estimated points regardless of the magnitude of the separation distance The metal product manufacturing method as described in any one of claim | item 5 -7.

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