JP2635891B2 - Method and apparatus for detecting welding groove shape - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for detecting a shape of a welding groove in groove welding.

[0002]

2. Description of the Related Art As demands for labor saving and quality improvement by automating welding work increase, even if the shape of a welding groove is irregular, the welding equipment side determines welding conditions and welding torch position according to the irregularity. It is becoming necessary to adjust and perform good welding automatically, and in order to achieve this, the technology for detecting the welding groove shape is an important technical point.
Japanese Patent Application Laid-Open No. 59-61574 discloses a technique relating to groove shape detection. In this case, as shown in FIG. 10, a vertical distance meter 1 for detecting a distance to a surface of a butt welding member 31 is arranged above a welding groove, and a pulse motor 8 is provided.
The longitudinal distance meter 1 is driven transversely to the welding line by a ball screw 10 or the like, and a beam such as a laser or the like emitted from the distance meter is directly radiated to the groove, and the butt welding member at each position in the transverse direction The distance (height) of 31 is measured. The distribution of the detection distance (height) in the horizontal direction indicates the cross-sectional shape of the groove.
That is, the method of detecting the groove shape by moving the vertical distance meter 1 in a direction perpendicular to the welding line (longitudinal direction of the groove) as shown in FIG. When the groove shape of the butt welding member 31 is detected, the distance (height) information of the welding groove is substantially equal to the cross section 32 perpendicular to the welding line direction and the straight line 33 intersecting the welding groove surface and the upper surface of the welding member. Since it is obtained by the entire line (33), the groove shape at the cross section 32, that is, the cross-sectional shape of the groove can be accurately measured.

[0003]

However, such a groove shape detection technique is applied to a welding groove when one side member of the groove is a wall-shaped welding member Mv, as shown in FIG. When applied to a welding groove having a step as shown in FIG. 12, there are the following problems.

That is, when applied to a welding groove formed by a wall-shaped welding member Mv and a butt welding member Mh,
As shown in FIG. 11, when the vertical distance meter 1 moves, the vertical distance meter 1 and the wall surface 4 of the wall-shaped welding member Mv interfere with each other. (Depth and width) cannot be measured. Regarding the collision between the wall 4 and the vertical distance meter 1, even if the moving range is set within a range where the vertical distance meter 1 does not collide with the wall 4 first, the wall position may be changed due to the bending of the welding member as the welding progresses. In many cases, the (horizontal direction) shifts, and the vertical distance meter 1 collides with the wall surface 4 and is damaged.

[0005] Further, even in a welding groove having a large step,
When the height of the wall is lower than the measurable range of the vertical distance meter 1, as shown in FIG. 12, the vertical distance meter 1 can be moved in a range straddling both sides of the groove, A distance meter with a large measuring range is expensive, and its size and weight increase, so the groove detection device increases in size and weight, and the setting properties (accurate positioning) of the distance meter during welding work are poor. To In terms of measurement accuracy, in particular,
Is inclined, the wall surface 4 side is a wall-shaped welding member M
Since only the position (height) of the upper end face 34 of v can be detected with high accuracy, the groove width estimated from the information of the vertical distance meter 1 has a large error, and the groove shape cannot be measured accurately and accurately. .

Due to such a problem, there is a variation in the groove shape in welding work of the welding member Mv such that the one side member of the groove is wall-shaped, large step, inclined, etc. (the groove cross-sectional shape in the groove longitudinal direction). There if uneven), the JP 59-
A conventional groove sensor disclosed in Japanese Patent No. 61574 detects a groove shape (particularly a groove width dimension) and controls welding conditions and a welding torch position to appropriate values based on the detected groove shape to perform welding. Can no longer be performed, and this greatly impedes securing welding quality and efficiency.

SUMMARY OF THE INVENTION An object of the present invention is to accurately measure the shape of a groove formed by a wall-shaped welded member, which is difficult to detect the groove shape as described above over the entire length in the transverse width direction. Do

[0008]

According to the invention of the present application, a lateral distance meter (2, 3) disposed on a side of a welding groove formed on one side by a wall-shaped welding member (Mv) is used to form the wall-shaped portion. The inclination information of the welding member (Mv) and the positional information from the lateral distance meter (2, 3) to the wall-shaped welding member (Mv) are obtained, and the positional information to the wall-shaped welding member (Mv) is obtained. On the basis of this, the vertical distance meter (1) disposed above the groove is traversed without interfering with the wall-shaped welding member (4 Mv to obtain the position information of the groove cross section, and the wall-shaped welding is performed. The width and depth of the groove surface are obtained from the inclination information of the member (Mv) and the position information of the groove cross section.The symbols in parentheses indicate the corresponding elements of the apparatus for implementing the present invention shown in the drawings. Show.

[0009]

[Action] The horizontal distance meter (2, 3) detects the horizontal distance at a plurality of locations in the vertical direction of the wall-shaped welding member (Mv), and the wall surface (4)
The position and the inclination of are known. In particular, the wall surface of the welded member (Mv)
(4) In most cases, a rolled surface of a steel sheet is obtained, and a very good signal is obtained, and estimation with high accuracy and reliability is possible.

Since the latest groove wall position on the traversing surface of the vertical distance meter (1) can be estimated from the position and inclination information of the wall surface (4), the vertical distance meter (1) is traversed. In order to avoid collision between the vertical distance meter (1) and the groove wall (4), set the appropriate horizontal movement position or range
In (1), the position of the surface (4 to 7) that defines the internal space of the groove, that is, the cross-sectional shape of the groove can be measured. Thus, a certain range of the groove bottom (7) for which position information cannot be obtained by the vertical distance meter (1) to avoid the interference collision of the vertical distance meter (1) is obtained by the vertical distance meter (1). Using the position information obtained and the wall position information obtained by the lateral distance meter (2, 3), it can be obtained by estimation (extrapolation) calculation, so the position of the entire surface (4 to 7) that defines the internal space of the groove That is, the entire shape of the groove cross section can be easily obtained.

[0011]

1 to 3 show one embodiment of an apparatus for carrying out the present invention. In FIG. 1, a support frame supported via a posture adjustment mechanism is supported by a not-shown welding moving mechanism main body (welding moving table) that can move in a direction substantially perpendicular to the paper surface in a direction substantially parallel to the upper surface 6 of the butt welding member Mh. 13, the ball screw 10
Are rotatably supported. The ball screw 10 is driven forward and backward by a pulse motor 8. A distance meter support member 11 is screw-connected to the ball screw 10, and a pulse motor
When the ball screw 10 rotates forward by the forward rotation of the motor 8, the support member 11 moves in the direction approaching the left side wall 4 of the wall-shaped welding member Mv (leftward), and the ball is rotated by the reverse rotation of the pulse motor 8. When the screw 10 is reversed, the support member 11 becomes a wall-shaped welding member Mv.
In the direction away from the wall surface 4 (rightward). The vertical distance meter 1 is mounted on the support member 11, and the vertical distance meter 1
Detects the distance from it to the object below it (the butt welding member Mh or the backing member Mr), that is, the height of the object. The horizontal distance meters 2 and 3 are mounted on a distance meter support member 12, which is fixed to a support frame 13. The lateral distance meters 2 and 3 detect the distance from the object to the left (the wall surface 4 of the wall-shaped welding member Mv), that is, the horizontal position of the object. These rangefinders 1-3
For example, a semiconductor laser optical displacement meter is used.

A rotary encoder 9 having a rotation direction detecting circuit is connected to the ball screw 10. The encoder 9 outputs a signal indicating the rotation direction and one signal per rotation of the screw 10 at a predetermined small angle. A pulse rotation synchronization pulse is given to the counter PC1. A home position sensor (not shown) is located at a retreat position (the right end of the moving range) on the movement path of the support member 11, and when the support member 11 reaches the retreat position, the home position sensor instructs the counter PC1 to clear. Give a signal. The counter PC1 has a rotary encoder 9
When a signal indicating forward rotation is given, the rotation synchronizing pulse is counted up, and when a signal indicating reverse rotation is given, counting up is performed. When the support member 11 is at the retracted position and the count value is cleared (count value = 0) by the clear instruction signal of the home position sensor, the count value of the counter PC1 is determined by the following. Shows how far to the left you are. That is, the count data of the counter PC1 is
Represents the position in the direction crossing the groove.

The vertical distance meter 1 is projected to the left from the support member 11 so that the vertical distance meter 1 can be applied to the V groove shown in FIG. May move further to the left than the left edge of the. The vertical distance meter 1 is supported by a support member 11 through two sets of angle adjustment mechanisms (not shown), and has a rotation angle about an axis parallel to the paper plane and perpendicular to the wall surface 4 and an axis perpendicular to the paper plane. The rotation angle about the center can be adjusted. With these adjustments, the detection direction of the vertical distance meter 1 can be set perpendicular to the upper surface 6 of the butt welding member Mh or parallel to the wall surface 4.

Similarly, the horizontal distance meters 2 and 3 are also not shown in FIG.
The rotation angle about an axis parallel to the paper plane and perpendicular to the upper surface 6 and the rotation angle about the axis perpendicular to the paper plane can be adjusted by being supported by the support member 12 via a set of angle adjustment mechanisms. With these adjustments, the detection directions of the lateral distance meters 2 and 3 can be set parallel to the upper surface 6 of the butt welding member Mh or perpendicular to the wall surface 4.

As shown in FIG. 2, the horizontal distance meters 2 and 3 are located at positions where the movement of the vertical distance meter 1 from the retracted position to the left limit position is not hindered. 10
Is set to accurately measure the distance from the left end of the vertical distance meter 1 to the left limit position.

Based on the configuration described above, a data processing device (computer) mainly including a microprocessor (CPU) is used.
D) The DPD sets the horizontal distance (position) information of the groove wall 4 measured by the horizontal distance meters 2 and 3 and the vertical distance meter 1 to the retracted position according to the horizontal distance information (corresponding to the retracted position of the support member 11). Information on the distance (height; welding groove depth) of the vertical distance meter 1 when the traverse movement is performed from right to just before hitting the wall surface 4 is collected. That is, the signals of the rangefinders 1 to 3 are converted into A / D converters A
The data is input to the CPU via an interface such as D1 to AD3 and the counter PC1. The horizontal drive of the vertical distance meter 1
This is performed by sending a pulse drive signal from the CPU to the motor driver MD1.

The position of the welding groove using the apparatus described above
The measurement of the shape will now be described. First, the ball screw 10 and the vertical distance meter 1 are set at a lateral position where there is a margin from the wall surface 4 with respect to the welding groove 14 having one side, and then the ball screw 10 is substantially perpendicular to the groove wall surface 4. (But welding member M
h is substantially parallel to the upper surface 6), and is not shown so that the measurable range (height direction) of the longitudinal distance meter 1 is sufficiently high to cover the butting member upper surface 6 and the groove bottom 7. Adjust the posture of the support frame 13 supported by the welding carriage (when the upper surface 6 of the butt welding member Mh is substantially horizontal as shown in FIG. 1, the center position of the adjustment range (zero scale)
Thus, the ball screw 10 is horizontal and the support members 11 and 12 are vertical). And by the angle adjustment mechanism of the above rangefinder,
Fine adjustment is made so that the detection directions of the horizontal distance meters 2 and 3 are parallel to the upper surface 6 and the detection direction of the vertical distance meter 1 is perpendicular to the upper surface 6 (the upper surface 6 of the butt welding member Mh shown in FIG. 1 is substantially horizontal). In the case of (1), the detection direction of the vertical distance meter 1 is vertical and the detection directions of the horizontal distance meters 2 and 3 are horizontal at the center position (0 scale) of the adjustment range.

When the upper surface 6 of the butt welding member Mh is substantially horizontal, the posture of the support frame is adjusted to the center position (0
Scale), and the standard is that the angle adjustment of the distance meters 1 to 3 is at the center position (0 scale) of the adjustment range, and the operator has adjusted these values to values different from 0. In this case, an adjustment value is input to the data processing device DPD from the operation board.

The data processing device DPD measures and calculates the groove shape as follows. First, the signals of the horizontal distance meters 2 and 3 facing the groove wall surface 4 are converted into A / D converters AD2 and AD3.
The detection points a and b in the overall coordinate system are estimated from the positions of the two lateral distance meters 2 and 3 and the detection distance signal as shown in FIG. a,
The straight line formula of the groove wall surface passing through b is obtained. Next, the horizontal position of the groove wall 4 at the height of the vertical distance meter 1 is calculated based on the straight line formula, and the groove assumed under the condition that the wall 4 does not interfere with the vertical distance meter 1 is calculated. In consideration of the width of the upper surface, an appropriate horizontal movement range (leftward limit position) of the vertical distance meter 1 is set, and the vertical distance meter 1 is driven leftward to that extent.

Each time the vertical distance meter 1 moves leftward by a predetermined short distance, the distance signal of the vertical distance meter 1 in the groove depth direction is converted into an A / D converter A
Via D1, and the position signal in the horizontal direction of the vertical distance meter 1, that is, count data of the counter PC1, is sequentially taken into the CPU.

The CPU uses the least-squares method for these signal groups to calculate the linear approximation of the upper surface 6 of the butt welding member Mh and the groove surface 5 of the butt welding member Mh in the overall coordinate system. A straight-line approximation formula and a straight-line approximation formula for the groove bottom 7, that is, the upper surface of the backing member Mr are obtained.

In the overall coordinate system, the groove wall surface 4, the upper surface 6 of the butt welding member Mh, the groove surface 5 of the butt welding member Mh, and the groove bottom 7 calculated above are calculated. As shown in FIG. 3, the coordinates of four points A, B, C, and D representing the shape characteristics of the groove are calculated based on the straight line formula, and the position and shape (width / depth) of the welding groove 14 are calculated. Is calculated. The above is the measurement of the groove shape when the distance meters 1 to 3 are located at a position in the longitudinal direction of the welding groove 14 (the direction perpendicular to the plane of FIG. 1).

The support frame 13 supported by the welding carriage and the above-described distance measuring device 24 mounted thereon are moved at low speed in the longitudinal direction of the welding groove 14 (perpendicular to the plane of FIG. 1). The welding is performed over the entire length in the longitudinal direction of the welding groove 14 while continuously moving or repeatedly moving and stopping a predetermined distance.

In the above-described embodiment, the horizontal distance meters 2 and 3 disposed below the vertical distance meter 1 are vertically arranged in two stages. However, as another method, the horizontal distance meters 2 and 3 are arranged in one stage. The horizontal distance meter may be moved in the vertical direction to measure the horizontal distance at each position in the vertical direction.

FIGS. 4 to 8 show another embodiment of an apparatus for practicing the present invention. In FIG. 4, the vertical distance meter 1 is mounted on the support member 11, similarly to the embodiment shown in FIG. Unlike the embodiment shown in FIG. 1, the horizontal distance meters 2 and 3 are mounted on the support member 11 via an angle adjusting mechanism, similarly to the vertical distance meter 1, and are above and below the vertical distance meter 1 in the vertical direction. Located on the side. FIG. 5 shows this positional relationship. Therefore, the horizontal distance meters 2 and 3 move in a horizontal direction integrally with the vertical distance meter 1. Here, as the vertical distance meter 1, for example, a semiconductor laser type optical displacement meter having a large measurement range (± 40 mm to ± 10 mm) is used, and the horizontal distance meters 2 and 3 have a short measurement range (20 mm or less). A small and optimal magnetic sensor is used for surface detection. Other configurations of the measurement mechanism are shown in FIG.
Are the same as those described above.

Based on the configuration described above, the distance information to the groove wall 4 of the horizontal distance meters 2 and 3 and the welding distance from the vertical distance meter when the vertical distance meter 1 is traversed by the groove information. Gather distance information in the depth direction and position information of the vertical distance meter. These signals are taken into the CPU via an interface such as an A / D converter and a pulse counter. When the vertical distance meter is moved, a signal is sent from the CPU to the motor control device to control the amount of movement.

In this embodiment, the data processing device DPD
Sends a command to the motor driver from the CPU and moves the vertical and horizontal distance meters 1, 2, and 3 from the retreat position (right limit position) toward the groove wall surface 4. An A / D converter A converts a distance signal in the groove depth direction obtained when the vertical distance meter 1 is traversed.
The count value of the counter PC1 representing the horizontal position of the vertical distance meter 1 via D1 is sequentially taken into the CPU.
FIG. 7 shows a plot of the information.

In the data processing device DPD, the limit of approach of the vertical and horizontal distance meters 1 to 3 to the groove wall 4, that is, the limit value of the distance signal detected by the horizontal distance meters 2 and 3 is set. During the above operation, the distance signals of the horizontal distance meters 2 and 3 are simultaneously monitored via the A / D converters AD2 and AD3, and an interrupt signal is given to the CPU when the detected distance reaches the limit value. . The CPU responds to this signal (the rangefinders 2 and 3 reach the wall approach limit), and the motor driver MD
A stop command is sent to 1 to stop the motor. Next, as shown in FIG. 6, the count value of the counter PC1 (horizontal position: horizontal axis) and the signals of the horizontal distance meters 2 and 3 (each detection distance a and b) are taken into the CPU and latched (held in the memory). Then, a return drive command is sent to the motor driver MD1 to return the distance meters 1 to 3 to the retracted position.

In calculating the groove shape, as shown in FIG.
The detection points a and b in the overall coordinate system are estimated from the positions of the two lateral distance meters 2 and 3 and the detection distance signals, and the straight line formula of the groove wall surface passing through these a and b is determined on the measurement cross section. . Next, the CPU uses a least-squares method with respect to the signal group (FIG. 7) detected by the vertical distance meter 1 during the horizontal movement, and as shown in FIG. 8, the butt welding member in the overall coordinate system. A linear approximation formula for the upper surface 6 of Mh, a linear approximation formula for the groove surface 5 of the butt welding member Mh, and a linear approximation formula for the groove bottom 7 are obtained. The linear equation in the overall coordinate system of the groove wall surface 4 of the wall-shaped welding member Mv, the upper surface 6 of the butt welding member Mh 6, the groove surface 5 of the butt welding member Mh, and the groove bottom 7 calculated above is also obtained. Then, the coordinates of four points A, B, C, and D representing the shape characteristics of the groove are calculated, and the position and shape (width / depth) of the welding groove are calculated.

The above is the measurement of the groove shape when the distance meters 1 to 3 are located at a position in the longitudinal direction of the welding groove 14 (the direction perpendicular to the plane of FIG. 1).

The support frame 13 supported by the welding carriage and the above-described distance measuring device 24 mounted thereon are moved at low speed in the longitudinal direction of the welding groove 14 (the direction perpendicular to the plane of FIG. 1). The welding is performed over the entire length in the longitudinal direction of the welding groove 14 while continuously moving or repeatedly moving and stopping a predetermined distance.

[0032]

The present invention has the following effects.

(1) The position and shape (width / depth dimension) of a welding groove can be efficiently and accurately measured for a single wall shape or a large step, particularly for a welding groove having a wall surface having a reverse slope.

(2) By realizing the groove shape measuring apparatus of the present invention, accurate groove position / shape information is input to an automatic welding system for controlling and performing welding conditions and a welding torch position during welding. , And the quality of the welding operation can be efficiently improved particularly for a work having a variation in the groove shape.

As described above, the practical effect is very large.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an apparatus for implementing the present invention.

FIG. 2 is a side view of the distance measuring mechanism 24 shown in FIG.

3 is a graph showing a groove shape represented by distance data obtained by a vertical distance meter 1 and horizontal distance meters 2 and 3 shown in FIG.

FIG. 4 is a block diagram showing another embodiment of an apparatus for implementing the present invention.

5 is a side view of the distance measuring mechanism 24 shown in FIG.

6 is a graph showing distance information obtained by the horizontal distance meters 2 and 3 shown in FIG.

7 is a graph showing distance information obtained by the vertical distance meter 1 shown in FIG.

8 is a graph showing a groove shape obtained from the distance information shown in FIGS. 6 and 7. FIG.

9A and 9B are perspective views of a welding member having a groove on one side wall, wherein FIG. 9A shows a case where a wall-shaped welding member is a cylindrical material and a butt welding member is a flange material, and FIG. Shows a case where both the welding member and the butt welding member are steel plates.

FIG. 10 is a perspective view showing a conventional V groove shape detection mode.

FIG. 11 is a cross-sectional view of a conventional groove shape measurement applied to a single-wall groove.

FIG. 12 is a cross-sectional view of a conventional groove shape measurement applied to a groove having a large step.

[Explanation of symbols]

Mh: Butt welding member Mv: Wall-shaped welding member Mr: Backing member 1: Vertical distance meter 2: Horizontal distance meter (upper) 3: Horizontal distance meter (lower) 4: Wall surface 5: Groove of butt welding member Surface 6: Upper surface of butt weld member 7: Bottom of groove 8: Pulse motor 9: Rotary encoder 10: Ball screw 11: Distance meter support member 12: Distance meter support member 13: Support frame 14: Weld groove 21: Detection information of horizontal distance meters 2 and 3 22: Vertical distance meter 1
Detection information 23: limit position of approach to the wall surface 4 24: distance measuring mechanism 31: welding member 32: cross section perpendicular to the welding direction 33: straight line where the cross section 32 intersects with the welding groove 34: upper surface of the wall-shaped welding member

Claims (3)

(57) [Claims] 1. A lateral distance meter disposed on a side of a welding groove formed on one side by a wall-shaped welding member. Obtaining positional information up to the welding member, based on the positional information up to the wall-shaped welding member, traverses a vertical distance meter disposed above the groove without interfering with the wall-shaped welding member. A method for detecting the shape of a welding groove, comprising obtaining position information of a groove cross section, and obtaining a width and a depth of a groove surface from the inclination information of the wall-shaped welding member and the position information of the groove cross section. 2. A vertical distance meter which is supported by a moving mechanism body which can move in a longitudinal direction of a welding groove formed by a wall-shaped welding member and which can move in a direction crossing the welding groove, and which is supported by the moving mechanism body. A horizontal distance meter for detecting the distance of the wall-shaped welding member, and a data processing device for generating cross-sectional information of the welding groove based on the detected values of the vertical distance meter and the horizontal distance meter.
A welding groove shape detection device comprising: 3. A support member which is supported by a moving mechanism body which can move in a longitudinal direction of a welding groove formed by a wall-shaped welding member and which can move in a direction crossing the welding groove, and which is supported by the supporting member. A vertical distance meter, a horizontal distance meter supported by the support member and detecting the distance of the wall-shaped welding member, and cross-sectional information of the welding groove is generated based on detection values of the vertical distance meter and the horizontal distance meter. A welding groove shape detecting device comprising a data processing device.