JPH04162963A - Detection of deviation of groove in production process for steel pipe - Google Patents

Abstract

PURPOSE:To facilitate the prior correction of a groove position when the groove position deviates by irradiating the part near the groove of a steel pipe with a laser slit light source, detecting the shadow thereof with a CCD camera for image processing, determining the bright line of the detected groove shape and detecting the deviation of the groove shape. CONSTITUTION:The steel pipe 1 is so disposed and fixed that its joint part faces downward. The image processing CCD camera 2 detects the joint part and executes automatic registration control. A moving stand 3 is a stand to automatically determine the position by image processing. A welding head 4 is inserted via a boom 5 into the inside surface of the steel pipe by traveling of a truck 6. A copying roll 8 is a guide roller inserting and travelling into the groove. The bright line 22 of the groove shape which the CCD camera projects by the laser slight light source 12 is inputted to an image processing computing element 13 and is subjected to digitalized processing computation. The bright line 22 of the groove line read by the camera is displayed by a monitor television 14. A parameter is set from the outside by a constant setter 15 and the output element meeting a control target is computed by an output computing element 16.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for detecting groove deviation in a steel pipe manufacturing process and correcting a welding position.

[Conventional technology]

As a conventional technique, as shown in Japanese Patent Application Laid-open No. 61-27178, slit light or scanned spot light is irradiated diagonally above the longitudinal direction of the groove at right angles to the longitudinal direction of the groove, and the surface of the groove is and the reflected light on the base material surface is imaged by an objective lens provided above the reflected light, and an elongated slit is located on the imaging plane of the reflected light on the base material surface in a direction perpendicular to the longitudinal direction of the groove. The position of the groove edge is detected by arranging a slit plate like this, detecting only the reflected light that passed through the slit with a detector, and performing one-dimensional signal processing on the detection signal with a signal processing device. There is a method for detecting groove edges.

[Issues with conventional technology]

In the above-mentioned conventional techniques, even if the groove position is detected, there is no disclosure regarding means for returning the groove position from the position where the groove has come off to the normal position.

[Means to solve the problem]

The present invention advantageously solves the problems of the prior art, by providing a CCD camera for image processing near the steel pipe groove, irradiating the vicinity of the steel pipe groove with a laser slit light source, and detecting the shadow in the above image. This is a method for detecting groove deviation in a steel pipe manufacturing process, which is characterized in that a deviation in the groove position is detected by detecting with a processing CCD camera and determining the detected groove shape bright line.

The present invention will be explained below with reference to the drawings.

〔Example〕

FIG. 1 is a diagram showing an embodiment of the present invention.

1 is a steel pipe (vibrator), which is fixed with the joint portion facing downward.

2 is a CCD camera for image processing, which detects joints of steel pipes and performs automatic positioning control.

Reference numeral 3 denotes a movable mount for groove positioning, which performs automatic positioning by image processing.

A welding head 4 is connected to a truck 6 via a boom 5, and is inserted into the steel pipe following the inner surface groove of the steel pipe as the truck moves.

5 is a boom, and a welding head 4 is attached to the tip.
It is inserted into the tube together with the tube.

Reference numeral 6 denotes a traveling truck, which is a power truck that inserts the welding head 4 into the steel pipe.

7 is a groove, which is a welded part (V-shaped opening) of the steel pipe.

Reference numeral 8 denotes a copying roll, which is a guide roller that is inserted and runs inside the steel pipe before it is inserted into the pipe.

FIG. 2 is a diagram showing the configuration of the image processing device.

Reference numeral 2 denotes the above-mentioned CCD camera for image processing, which inputs the groove shape bright line 22 projected onto the steel pipe groove portion 20 by the laser slit light source 12 to the image processing calculator 13.

12 is a laser slit light source that irradiates the steel pipe groove portion 20 to generate a groove shape bright line 22.

Reference numeral 13 denotes an image processing calculator, which performs numerical processing calculations on images read by the image processing CCD camera.

Reference numeral 14 denotes a monitor television, which displays the groove shape bright line 22 read by the image processing CCD camera 2.

Reference numeral 15 denotes a constant setting device, which sets various parameters from the outside.

Reference numeral 16 denotes an output calculator, which is a part that calculates output elements that match the control target.

Reference numeral I7 denotes an image processing interface section, which is connected to other devices and provides the necessary image processing amount to the controlled object.

Reference numeral 18 denotes a sequence controller interface section, which is directly connected to the image processing interface section 17 and processes input/output to be arithmetic-controlled by the sequence controller.

Reference numeral 19 denotes a sequence controller calculation unit, which outputs a control force according to the target to the controlled object via the sequence controller interface unit 18 by calculating the control output output from the image processing device. be.

Reference numeral 20 denotes a steel pipe groove (part), which has a groove that is subject to image processing control.

2I is an image processing area, which processes images projected in this area.

22 is a groove-shaped bright line, and the laser slit light source 12
The shape of the groove is displayed as a bright line and read by the CCD camera 2.

FIG. 3 is a diagram showing the control flow of the present invention.

1 is a trolley automatic process selection and start, which starts the operation of inserting the welding head into the steel pipe.

2 is a tube end deceleration position, which is used to determine whether or not to detect groove deviation.

Reference numeral 3 is a groove deviation cancellation, which cancels the control operation when groove deviation detection is not performed in 2.

4 is the start of the groove detection mode, and 2 is for sending a start signal to the image processing device when detecting groove deviation.

Reference numeral 5 indicates groove deviation detection, in which the horizontal deviation of the groove detected and measured by the image processing device is stored as data when it reaches a set value. Data outside the set range will not be processed. In this case, the range of reading groove center analog data at the set sampling period can be changed to ±3 mm (C setting can be changed).

6 is continuous detection n times, and when the left-right deviation of the groove reaching the value set in 5 is detected n times consecutively, it is determined that groove deviation has been detected and a control output is performed. If the number of consecutive times does not reach n, the deviation data is not processed at that point. It turns ON when the groove deviation detection is detected a set number of times consecutively. n = 3 times (settings can be changed).

7 is a bevelless output, which is output when the bevel is not visible during image processing, that is, when traveling in a non-beveled area, and is output by ANDing the analog output and bevelless output. The driving judgment is based on the part other than the front part. If both inputs, analog output and groove output are not ANDed, no control output processing is performed.

Reference numeral 8 is a detection confirmation timer, and the signal processed and output in step 7 continues for a set period of time, and if it does not continue, it is not output as the final output.

9 is the tube end deceleration position; if the tube end is not at the tube end deceleration position, the final output of 6 or 8 is valid; if it is at the tube end deceleration position, the groove deviation detection control is canceled.

In other words, it ends. This detection of groove deviation is performed only from the start to the tube end deceleration position.

lO is ON when the groove is off, and when the final output is output, if it is not at the tube end position, the groove is off is output.

Reference numeral 11 indicates the automatic mode termination of the cart moving process, and when the bevel is outputted in step 10, the automatic mode of the cart moving process is switched off and automatically stopped.

FIG. 4 shows the output specifications of the image processing device.

A indicates when the groove center is detected, and the groove shape bright line is displayed in the center on the monitor screen, indicating that the groove center is detected.

The state at this time indicates that it has been inserted normally at the center of the groove.

B is when the groove is shifted to the center or to the right, and the groove shape bright line is displayed on the monitor screen at the top of the screen, and the value ranges from 0 to +5 depending on the amount of shift.
Outputs analog output in the V range.

The state at this time indicates that the vehicle is running off the groove to the right. This deviation analog data is processed to detect whether the machine is running outside of the groove.

C is when the center of the groove is shifted to the left, and the groove shape bright line is displayed at the bottom of the monitor screen, and it is ON-5 depending on the amount of shift.
Outputs analog output in the range of v.

The condition at this time indicates that the vehicle is running off the groove to the left. This deviation analog data is processed to detect whether the machine is running outside the groove.

In D, the center of the groove is not visible, indicating that the vehicle is traveling in a place with no groove at all. In this case, the deviation analog data should be “0” and the bevelless output should be AN
By performing the D process, it is detected that the vehicle is traveling outside the groove and in a place where there is no groove.

〔Effect of the invention〕

To make it possible to correct the groove position in advance without stopping the progress of a welding machine when the groove position is deviated due to uninvention.

[Brief explanation of the drawing]

Fig. 1 is a schematic explanatory diagram of the groove deviation detection method of the present invention, Fig. 2 is a block diagram showing the configuration of an image processing device, Fig. 3 is a flowchart showing the groove deviation detection operation, and Fig. 4 is image processing. FIG. 3 is an explanatory diagram of output specifications of the device. Applicant Nippon Steel Corporation Patent Attorney Minoru Aoyagi Figure 3

Claims (1)

[Claims] 1. A CCD camera for image processing is installed near the steel pipe groove,
Irradiate the vicinity of the steel pipe groove with a laser slit light source,
A method for detecting groove deviation in a steel pipe manufacturing process, characterized in that a shift in the groove position is detected by detecting the shadow using the image processing CCD camera and determining the detected groove shape bright line.