JPH02104474A - Measuring instrument for pipe inside welding position - Google Patents

Abstract

PURPOSE:To accurately grasp the welding position inside a metallic pipe by fitting a face plate to rotate with a pipe axis as a center on a carriage movable in the direction of a pipe inside axis, lighting up a weld zone on the face plate and measuring its position by a telecamera at the time of performing circumferential welding on the inside of the metallic pipe. CONSTITUTION:In order to weld the welding position WL of the inside of the metallic pipe 1 from the inside, the carriage 2 to move along the pipe axis in the pipe is provided and the face plate 13 which rotates by a motor A, and advances and retreats by a gear 12 by a motor B is fitted on the carriage 2. The carriage 2 is fixed on the pipe inside by a piston cylinder 3 and a welding torch 16 and the telecamera 15 are fitted uniaxially and a light source 17 for lighting up a welding point is fitted at a specific angle on the face plate 13. The welding position of the pipe inside is grasped by the light source 17 and the telecamera 15 by the movement in the X direction of the face plate 13 and at the position, the face plate 13 is rotated by the motor A and the welding position of the pipe inside is welded with high accuracy by the welding torch 16 fitted uniaxially with the telecamera 15.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a welding position measuring device for instructing an automatic welding machine that circumferentially welds the inner surface of a pipe about the position to be welded in advance.

[Prior Art] When welding a joint for a newly constructed pipe, if welding from the outer periphery of the pipe is difficult or if the pipe is thick, welding from within the pipe is required. In addition, welding is performed from inside the pipe to repair or reinforce welding defects (insufficient backing, mismatched parts) in existing pipes.

When welding inside a pipe, if the pipe diameter is small, humans cannot enter the pipe, so welding positions are detected from outside the pipe using a television camera, etc., and welding is performed automatically by remote control. This automatic welding is performed in advance by determining the three-dimensional coordinates of the position to be welded (pipe axis direction X, circumferential direction Y
, radial direction Z) and memorize them, a teaching playback method has been adopted in which the welding torch is positioned at these coordinates and the welding is performed.

Conventionally, a measuring device for measuring the position to be welded in this teaching playback welding has a dolly 41 moving inside the pipe as shown in FIG. A TV camera 43 is fixed to the face plate facing the pipe wall, and the face plate 42 is mounted within the field of view of the TV camera 43.
A mechanical displacement meter 4 is placed in contact with the pipe wall in the radial direction from 2.
4 is provided, and the face plate is rotated and moved in the direction of the tube axis so that the tip of the displacement meter 44 matches a predetermined position (groove or welding defect) on the tube wall to be welded photographed by the television camera 43. A device was used to measure the X, Y, and Z coordinates.

[Problems to be Solved by the Invention] However, with the conventional method, as shown in Fig. 8, there is a misalignment in the position to be welded, and in bent corners such as miter bends, the radial direction is not accurate. In addition to being unable to measure the displacement (Z) of the mechanical displacement meter, there was a drawback that the tip of the mechanical displacement meter was bent and damaged when moving in the tube axis direction and circumferential direction. In order to eliminate this drawback, it is conceivable to use a non-contact displacement meter using eddy current or the like instead of a mechanical displacement meter. However, although damage to the displacement meter can be prevented in this case, since these non-contact displacement meters measure the average displacement of the area they are made of, it is not possible to accurately measure a point.

SUMMARY OF THE INVENTION The present invention solves these conventional problems and provides an in-pipe welding position measuring device that is less prone to failure and can accurately teach the position to be welded and perform automatic welding. purpose.

[Means for Solving the Problems] A welding position measuring device of the present invention for achieving this object is configured as follows. That is, in an in-pipe welding device that is mounted on a cart that is movable in the axial direction of the pipe and performs automatic welding by teaching the welding position in advance, the dolly is rotatable around the pipe axis and movable in the pipe axial direction. A face plate is attached, and a welding torch that is guided and driven in the radial direction, a television camera that is fixed so that its optical axis center coincides with the radial direction and points toward the inner wall of the tube, and the optical axis center of the television camera are attached to the face plate. a light source that is guided and driven parallel to the optical axis center of the television camera while maintaining a constant inclination angle with respect to the television camera, and the optical axis center of the television camera and the optical axis center of the light source are parallel to the face plate. an angle sensor that detects the amount of rotation of the face plate, a displacement sensor that detects the amount of movement of the face plate in the tube axis direction, and a displacement sensor that detects the amount of movement of the light source; and a displacement sensor for detecting the radial movement of the welding torch.

[Function] In the present invention, the angle of the face plate in the tube circumferential direction and the displacement in the tube axis direction,
In addition to accurately detecting the displacement of the optical axis and the radial direction of the welding torch, the position to be welded is measured in a non-contact manner using an optical means that maintains a constant positional relationship with the television camera. Therefore, the welding position within the pipe can be accurately determined.

[Example] Examples will be described below based on the drawings. FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, and FIG. 2 is a view taken along the line A-A in FIG.
FIG. 3 is a view taken along the line B--B in FIG. 2.

The measuring device of the present invention is installed at the tip of a truck 2 that runs inside a tube 1 in the tube axis direction, together with a welding torch, a cleaning device, and the like. The trolley 2 is connected to an intra-pipe moving device (not shown), moves within the pipe 1, and is fixed at a predetermined position by being pressed against the pipe wall by a plurality of piston cylinders 3 provided outside the cylindrical body.

Inside the truck body 4, a drum 5 supported by a bearing 6 in the gap between the outer periphery and the inner surface of the truck body is connected to a motor A fixed to the truck body 4, and is driven to rotate for the tube shaft. It's Nishide. An angle sensor such as an encoder 7 is connected to the motor rotation shaft, and measures the rotation angle of the drum 5 from the rotation angle of the motor shaft.

Corresponding through holes are provided in the front portions of the tram 5 and the bogie 2, and a shaft 8 having a face plate 13 fixed to its tip is inserted into the drum 5 through the through holes. The shaft 8 is provided with a key groove 9, which is fitted into the protrusion of a guide lO fixed to the drum through hole, so that the shaft 8 is movable in the tube axis direction while rotation with the drum 5 is restrained. ing.

Further, the shaft 8 is provided with a rack 11, and the rack 11 meshes with a gear 12 driven by a motor B fixed to the drum 5.

With the above configuration, the face plate 13 can be rotated via the drum 5 by driving the motor A, and the face plate 13 can be moved over a certain range in the tube axis direction by driving the motor B. Note that motor A and motor B are driven by remote control from outside the tube.

On the other hand, a displacement sensor, for example, an encoder 14 is fixed to the rotating shaft of the gear 12, and the shaft 8 is moved in the tube axis direction ff1 based on the rotation of the gear 12, that is, the amount of rotation of the motor B.
(displacement in the X direction).

A television camera 15, a light source 17,
A welding torch 16 and the like are provided. TV camera 15
are fixed to the face plate 13 so as to align the centers of their optical axes in the radial direction and to photograph the tube wall.

On the side of the television camera 15, a light source 17 that projects cross slit or spot light toward the tube wall is installed.
It is arranged so as to be oriented at an angle θ with respect to the optical axis center of No. 5. Further, the centers of both the optical axes of the camera and the light source are arranged in the same plane perpendicular to the tube axis, and the light source 17 is a slide member fixed to the face plate 13 parallel to the center of the optical axis of the television camera 15. It is attached to 18. Furthermore, a chain 19 driven by a motor C is arranged parallel to the slide member on the side of the slide member 18, and a support portion 23 of the light source 17 is connected to a part of the chain 19.

The reason why the optical axis center of the camera and the optical axis center of the light source are located in the same plane perpendicular to the tube axis is that in this way, even if the distance (Z) from the tube wall changes, the cross slit light ( This is because the welding position (or spot light) can be aligned with the X-axis center reference line of the television screen, and the X-axis coordinate can be measured when the welding position is aligned with the reference line. If both optical axes are not in the same plane, the cross slit light (or spot light)
If it deviates from the axis center reference line, and if Z changes, it will move in the X-axis direction on the TV screen, and the welding position will deviate from the welding position that was aligned with the X-axis center reference line, making it difficult to determine the exact welding position coordinates. This causes the inconvenience that it cannot be measured.

Chain 19 is a drive gear (pulley) connected to motor C.
20 and the driven gear 21 in a parallel manner. A Z-direction displacement sensor 22 (for example, a potentiometer) is attached to the rotating shaft of the driven gear 21 to measure the amount of movement of the light source. As a result, the cross slit or spot of the light source can be moved in parallel while maintaining a constant angle θ with respect to the center of the optical axis of the television camera 15. Incidentally, the measurement accuracy will be better if this angle θ is made larger, but for convenience of installation, it is practically set in the range of 45° to 15° (preferably about 30°).

The welding torch I6 is guided and driven in the radial direction of the tube, and
It is necessary to provide a means to measure the amount of movement. Further, the welding torch 16 must be arranged so that the spatter scattered when the arc is generated does not cause an adverse effect on the television camera 15, the light source 17, etc. Therefore, in this embodiment, the welding torch 16 is placed on the opposite side (180°) of the television camera 15.
The guide drive and movement amount measuring means are also used as the guide driving and movement amount measurement means of the light source.

Of course, the radial movement of the welding torch and the means for measuring the amount of movement thereof may be provided independently. It should be noted that the driving means and measuring means for each part shown in this embodiment are merely examples, and there is no problem in using other known means instead.

Note that reference lines for the X and Y axes are provided on the screen of the television on which the image sent from the television camera is displayed, with the center as the intersection point.

Next, a method of measuring a welding position using the apparatus of the present invention will be explained.

■ Travel the trolley 2 while monitoring the TV screen photographed by the television camera 15 (the X-axis of the screen is the photographed range in the tube axis direction, and the Y-axis is the photographed range in the tube circumferential direction),
Stop near the center of the reference line X-axis of the TV screen and clamp the trolley.

■ Drive the motor A to rotate the face plate 13 around the tube axis, and set the face plate position to either the first, bottom or left side of the tube (at this time, the face plate rotation angle ψ = 0). ) ■Drive the motor B and move the face plate so that the center of the X-axis of the reference line on the TV screen matches the position W14 where welding is to be performed (center part of the stepchild) 55 (Fig. 4) The motor C is driven and the light source is moved as shown by the dotted line so that the cross slit or spot light SL projected from the light source 17 onto the tube wall on the screen coincides with the center of the reference %Q Y axis. (Fig. 5) ■ In this state, input the data as initial value data into a data recorder (not shown). 3゜ψ”0', X=Xo, Z=ZQ (about ψ=50 or ψ=10°) Rotate the face plate around the tube axis and stop.

(2) Drive the motor B and adjust the face plate in the X direction so that the position to be welded at the angle ψ is aligned with the center of the reference line X axis of the TV screen. At this time, the encoder 7 measures the displacement of the face plate in the tube axis direction. (Fig. 6) ① Drive the motor C so that the cross slit or the spot light coincides with the center of the reference line Y1, if there is a deviation e'7. The radial displacement of the light source at this time is measured by the potentiometer 22. (7i1) ■ In this state, the data is captured and stored using a data recorder.

[Phase] Similarly, the face plate is rotated 3 [phase] at every predetermined pitch angle ψ.
il)' Rotate to store data on tube axial displacement <X> and radial displacement (Z).

As a result, the data shown in the table below is recorded.

(2) Thereafter, while reading the stored welding position data and performing predetermined calculations, the welding torch is controlled in the X and Z directions and then driven in the tube circumferential direction to perform automatic welding.

Note that if the angular pitch ψ at which data is taken in is coarse, an intermediate value is interpolated by calculation.

[Results of the Invention] According to the present invention, since the position to be welded is measured without contact, the device does not malfunction even when the grooves are misaligned or at an inclined joint such as a miter bend. In addition, since displacement in the radial direction can be measured optically, even if the position to be welded has a complex shape (misalignment, inclination, etc.), it can be measured at a point and accurate data can be obtained, resulting in high-quality welding. It is possible to do this.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the entire measuring device according to the present invention, FIG. 2 is a view taken in the direction of the arrow 87B in FIG. 1, FIG. 3 is a view taken in the direction of the arrow 87B in FIG. FIG. 6 and FIG. 7 are explanatory diagrams showing the operation procedure in the invention, FIGS. 6 and 7 are explanatory diagrams showing the operation situation on a television screen performed using the apparatus of the present invention, and FIG. 8 is an explanatory diagram of a conventional example. 1... Pipe, 2... Cart, 3... Piston cylinder, 4... Cart body, 5... Drum, 6... Bearing, 7°14... Encoder, 8... shaft,
9... Keyway, 10... Guide, 11... Rack, 12... Gear, 13... Face plate, 15... Television camera, 1 B-... Welding torch, 17... light source, 1
8...Slide member, ]9...Chain, 20...
・Drive gear, 21--Driven gear, 22--Potentiometer, 23--Support part, A, B, C... Motor Applicant's representative Patent attorney Tomoyuki Ya Fuki (and 1 other person) 2nd Figure 4 Eup 5th side

Claims (1)

[Claims] 1. An in-pipe welding device that is mounted on a cart movable in the axial direction of the pipe and performs automatic welding by teaching the welding position in advance, which A face plate is movably attached to the trolley, a welding torch guided and driven in the radial direction, and a television camera fixed to the face plate so as to align its optical axis center in the radial direction and point toward the inner wall of the pipe; a light source that is guided and driven parallel to the optical axis center of the television camera while maintaining a constant inclination angle with respect to the optical axis center of the television camera, and the optical axis center of the television camera and the optical axis center of the light source. is arranged to be located in the same plane parallel to the face plate, and further includes an angle sensor that detects the amount of rotation of the face plate, a displacement sensor that detects the amount of movement of the face plate in the tube axis direction, and an angle sensor that detects the amount of movement of the light source. 1. An in-pipe welding position measuring device, comprising: a displacement sensor for detecting displacement; and a displacement sensor for detecting radial movement of a welding torch.