JPH1110223A - Method for controlling cutter position of edge preparing device for spiral steel tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the cutter position of an edge preparing device for spiral steel tubes by following a seam. SOLUTION: Two CCd cameras are moved in the direction of a y-coordinate axis and their positions are detected with a camera position output unit. Before starting measurement, a distance Y12 in the direction of the y-coordinate axis and a proper position of the cameras are set based on the measuring condition of a steel tube 1 and the cameras are moved to the set positions with a position arithmetic unit and a camera position controller. In an image processor, image processing of the images from the cameras is executed, a seam 12 is detected and also the slope angles m1 , m2 of the seam 12 to a z-coordinate axis are calculated. Based on the calculated data m1 , m2 and position data in the z-coordinate axis of the cameras, the outside diameter D of the steel tube and the pitch L of a seam spiral are calculated. The data of the outside diameter of the steel tube, of the pitch L of the seam spiral and the position data of a cutter and the cameras are inputted to a cutter position controller and the coordinate of the optimum position of the cutter is calculated. By controlling the cutter position based on the calculated result, the edge preparation following the seam 12 is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manufacturing process for manufacturing a steel pipe while bending a steel sheet in a spiral shape. The present invention relates to a method for controlling a cutter position of a spiral steel pipe beveling apparatus for controlling a position according to the seam.

[0002]

2. Description of the Related Art In a spiral steel pipe making facility, a steel sheet is bent into a spiral shape and formed into a steel pipe, and the formed steel pipe is welded to a seam while rotating around the center axis of the pipe as a center of rotation. It is manufactured by doing. The seam welding process involves welding the inner surface of the steel pipe,
The outer surface of the steel pipe is beveled by a beveling device, and then the outer surface is welded. In the above-mentioned outer surface groove processing, in order to secure and automate the quality of the welded portion, the seam portion is automatically detected, and the position of the cutter of the groove processing device is set to the outer surface of the seam portion (hereinafter referred to as “external surface seam”). ") Is important.

A method for detecting a seam portion is disclosed in Japanese Unexamined Patent Publication No.
Japanese Patent No. 68815 discloses a detection method using a laser sensor (hereinafter, referred to as “prior art 1”). JP 5
Japanese Patent Application Laid-Open No. 3-76141 and Japanese Patent Application Laid-Open No. 5-138242 disclose a scribe line on a steel plate at a predetermined distance from an edge thereof, detect the scribe line with a television camera, and detect the relative position. A method for indirectly detecting a relationship is disclosed (hereinafter, referred to as “prior art 2”).

In each case, the position of the cutter is determined from the amount of change in the seam detection position.

[0005]

If the seam can be detected at the position of the cutting edge of the cutter, accurate follow-up is possible. However, when the seam is detected at the position in front of the cutting edge, the seam shape is a cylindrical steel pipe. Since the surface of the steel pipe is formed in a spiral shape, it differs depending on the outer diameter of the steel pipe. The amount of movement of the cutter in the direction parallel to the steel pipe center axis with respect to the fluctuation amount in the direction parallel to the steel pipe center axis at the seam detection position differs depending on the steel pipe outer diameter. For this reason, there is a problem that the cutter cannot follow the seam well.

[0006] Furthermore, in order to maintain the quality of the steel pipe during manufacture, it is usually necessary to measure the outer diameter of the manufactured steel pipe before the outer surface welding. As described above, in the groove preparation of the outer surface of the seam portion, it is necessary to detect the seam position and to measure the width of the supply steel plate and the outer diameter of the steel pipe. As a method for measuring the outer diameter of a steel pipe, JP-A-7-83644 discloses a measuring method using a surface wave (hereinafter, referred to as “prior art 3”), and
JP-A-5-23733 and JP-A-6-1941
No. 28 discloses a measurement method using a laser (hereinafter, referred to as “prior art 4”).

However, in any case, since the seam position detector and the steel pipe outer diameter measuring device are different devices,
There is a problem that a large installation space is required and furthermore, expensive equipment is required.

Accordingly, an object of the present invention is to provide a spiral steel pipe groove processing apparatus capable of performing seam position detection and steel pipe outer diameter measurement with the same apparatus and accurately controlling the cutter position of the groove processing apparatus. An object of the present invention is to provide a cutter position control method.

[0009]

According to the first aspect of the present invention,
Spiral steel pipe groove that captures the seam on the outer peripheral surface of the spiral steel pipe with a television camera, detects the position of the seam by image processing based on the captured image signal, and imitates the cutter of the groove processing device to the seam. In a cutter position control method for a processing apparatus, two televisions are arranged in parallel to a central axis of a spiral steel pipe and always at a constant height with respect to a steel pipe supporting roller device that supports the spiral steel pipe. A camera is arranged, and each of the two television cameras images the seam with a direction parallel to a central axis of the steel pipe as an abscissa axis and a radial direction of the spiral steel pipe as an ordinate axis. Two sets of seam positions of plane coordinates by the abscissa axis and the ordinate axis are detected by image processing based on Detecting the inclination angle of the seam formed by the seam and the direction parallel to the central axis of the spiral steel pipe, and determining the inclination angle of the spiral steel pipe from the distance between the two sets of seam positions and the inclination angle of the seam. Calculating the outer diameter and the spiral pitch of the seam, calculating the control position of the cutter from the outer diameter of the spiral steel pipe and the spiral pitch of the seam, and matching the position of the cutter with the control position of the cutter. It has.

[0010]

Next, an embodiment of the present invention will be described with reference to the drawings. (1) First, a method of detecting a position and a seam inclination angle by a television camera will be described.

FIG. 1 is a structural view showing an apparatus configuration according to an embodiment of a cutter position control method for a spiral steel pipe groove processing apparatus according to an embodiment of the present invention in a state where a spiral steel pipe is viewed from the side, and FIG. FIG. 3 is a configuration diagram showing a spiral steel pipe in a cross section taken along the line AA of FIG. 1 showing a device configuration according to one embodiment of the present invention. FIG. 3 is a diagram showing detection of a position and a seam inclination angle by a television camera according to one embodiment of the present invention. It is explanatory drawing which shows a method and shows the image obtained by imaging with the television camera. The TV camera is installed parallel to the central axis of the spiral steel pipe. In other words, the image is set so that the horizontal coordinate axis (z coordinate axis) of the image is parallel to the central axis of the steel pipe (FIG. 3).
reference).

Obtained by a television camera (CCD camera) 3
In the captured image, a measurement
Rear EA₁, EA_Two, And within the area at the center of each area
Image processing so that the center of the seam 12 detected in
Set. Also, area EA ₁Is the direction of the y coordinate axis in the image
Set at the center, search for seams in the z-coordinate direction in image processing
Camera driving device 31 so that it is always centered in the image.
Control. This uniquely sets the seam position to the camera position
It is determined by the output device 32. Also, area EA_TwoTo
Also search seam position in z coordinate axis direction by image processing
Set to By these, the area EA₁・ E
A_TwoDistance z in the z-coordinate axis direction_zAnd y coordinate axis direction
Distance ΔY_YIs calculated image-wise, and the seam
The tilt angle m with respect to the z coordinate axis is calculated by the following equation (1).
Ask for it.

_M = ΔY _Y / ΔZ _z (1) (2) Next, a method of obtaining the outer diameter of the spiral steel pipe and the seam helical pitch from the measured data of the television camera will be described with reference to FIG.

FIG. 4 is an explanatory diagram showing a method for calculating the outer diameter of the steel pipe and the seam spiral pitch according to one embodiment of the present invention. CCD cameras 3, 4 and a camera position output device 3, which are arranged parallel to the central axis of the steel pipe and are always arranged at a constant height with respect to the steel pipe supporting roller device 10.
From the data obtained in 2, 42, the outer diameter of the steel pipe and the seam spiral pitch are calculated by the following method.

It is assumed that the outer diameter of the steel pipe shown in the front view of the steel pipe 1 on the left side in FIG. 4 is D, and the helical pitch shown in the side view of the steel pipe 1 on the right side of FIG. Z · y plane coordinates of the point A ₁ that staring at the CCD camera 3, assuming an angle between y coordinate theta ₁ and _{(L · θ 1 / (2} · π), - D / 2 · cosθ 1) Becomes

[0016] in the vicinity of the inclination with respect to the z-axis at the point A ₁ of the seam curves l _{point, (A 1 '(θ =} θ 1 -Δθ), A 1''(θ = θ 1 + Δ
θ)). Equation 1 shows.

[0017]

(Equation 1)

Further, z of a straight line between points A ₁ ′ and A ₁ ″ is
The inclination m _{1 with} respect to the coordinate axis is given by Equation 2.

[0019]

(Equation 2)

Here, when Δθ → 0, the slope m ₁ is the point A
_{It has} a slope of ₁ . From Equation 3

[0021]

(Equation 3)

M ₁ = π · D · sin θ ₁ / L (2) Similarly, the xy plane coordinates of the point A ₂ glared by the CCD camera 4 are θ ₂ with respect to the y coordinate axis. Assuming that (L · θ ₂ / (2 · π), −D / 2 · cos θ ₂ ).

The inclination m ₂ of the seam curve 1 with respect to the z coordinate axis at the point A ₂ is m ₂ = π · D · sin θ ₂ / L (3) The distance Y ₁₂ between the points A ₁ and A _{2 in} the y coordinate axis direction. Is Y ₁₂ = (− D / 2) · cos θ ₂ − ｛− (D / 2) cos θ ₁ ｝ = (− D / 2) · (cos θ ₂ −cos θ ₁ ) (4) Point A ₁ · A If the z axis direction of the distance Z ₁₂ between the _two organizing _{Z 12 = L · (θ 2} -θ 1) / (2 · π) ··· (5) equation (2) ~ (5), πDsinθ 1 - m ₁ L = 0... (2) ′ πD sin θ ₂ −m ₂ L = 0... (3) ′ cos θ ₁ −cos θ ₂ − (2Y ₁₂ / D) = 0... (4) ′ θ ₁ −θ ₂ + 2πZ ₁₂ / L = 0 (5) ′ As described above, m ₁ and m ₂ are obtained from the image processing results of the images obtained from the cameras 3 and 4, as described in the preceding section. Can be Y ₁₂ is a camera 3 and 4 with respect to the support roller device 10, has been arranged in a predetermined height is preset to a constant value. Z ₁₂ is a camera position output device 32
And from the position data Z _A and Z _B in the z-coordinate axis direction obtained by steps 42 and 42. Equation (2) ′
-(5) ′, known numbers: m ₁ , m ₂ , Y ₁₂ ,
From Z ₁₂ and unknowns: D, θ ₁ , θ ₂ , and L, the solution of the above simultaneous equations is obtained, and unknowns θ ₁ , θ ₂ , D, and L can be calculated.

Next, a method using the Newton-Raphson method will be described as an example of solving the above equations (2) ′ to (5) ′. The method consists of n unknowns x ₁ , x ₂ .
_According to the concept of an n-ary simultaneous nonlinear equation having n.

When the vector function F (X) is Taylor-expanded in the vicinity of X = X ₀ and the second-order or higher-order term of (X−X ₀ ) is ignored, the following equation is obtained. F (X) = F (X ₀ ) + G (X ₀ ) (X−X ₀ ) (a) where G (X ₀ ) is an n × n regular matrix, and its i, j
The element g _ij (X ₀ ) is given by Expression 4.

[0026]

(Equation 4)

Next, by placing the F (x) = 0, X = X 1, X 1 = X 0 -G (X 0) -1 · F (X 0) ··· (c) is obtained . Therefore, the iterative equation is: X _{k + 1} = X _k −G (X _k ) ⁻¹ · F (X _k ) (d) Therefore, the relative error Z for each element of the vector X _k is within the relative allowable error ε. Iteratively calculate until.

The solutions of Equations (2) 'to (5)' are given by Equations (5) and (6).
It is as follows.

[0029]

(Equation 5)

[0030]

(Equation 6)

An initial approximate solution vector X ₀ is determined. X ₀ = (X ₁ ⁽⁰⁾ , X2 ⁽⁰⁾ ,... X _n ⁽⁰⁾ ) =
(C ₁ , c ₂ ··· c _n ) By substituting X ₀ into the ^T equations (e) and (f), F (X ₀ ), G
Calculate (X ₀ ).

Simultaneous equations -G (X ₀ ) ^-1 · F (X ₀ ) ≡C = (C ₁ , C ₂ ,...
C _n ) Solve ^T.

[0033] _{X 1 = X 0 -G (X} 0) -1 · F (X 0) = X 0 + C = (C 1 (1), C 2 (1) ·· C n (1)) T in the same manner To obtain X ₂ and X ₃ .

The above-mentioned repetition is executed until the following equation (7) is obtained.

[0035]

(Equation 7)

Table 1 shows a calculation example based on the above.

[0037]

[Table 1]

(3) Next, referring to FIG. 5, a method for determining the amount of movement of the cutter position from the values obtained above will be described. FIG. 5 is an explanatory diagram showing a method for determining the amount of movement of the cutter position according to an embodiment of the present invention.

Assuming that the outer diameter D of the steel pipe calculated as described above and the value before the change are D ₀ , when the value changes from D ₀ to D,
The amount of movement ΔR of the cutter in the steel pipe radial direction (y-coordinate axis direction)
ΔR = (D−D ₀ ) / 2 (6) From Equation (6), the correction position of the cutter 2 in the steel pipe radial direction (y coordinate axis direction) can be determined.

The amount of movement in the direction parallel to the central axis of the steel pipe (the direction of the z coordinate axis) uses the spiral pitch L of the seam calculated as described above. The helical pitch before and after the change is defined as L ₀ and L. _Let Z _A0 and Z _C0 be based on the position B of the camera 3 and the cutter 2 before the change, and let Z ₀ be the distance between the spiral start E point of the seam and the B point. As the position Z _A is [Delta] Z _A variation amount relative to the B point after the camera 3 _{change, Z A = Z A0 + ΔZ} A ··· (7) where, Z _A0, ΔZ _A: known number, Z _0: Unknown.

From the change in the helical pitch, (Z _A + Z ₀ ) / (Z _A0 + Z ₀ ) = L / L ₀ (8) From equations (7) and (8), (Z _A0 + ΔZ _A + Z) ₀ ) / (Z _A0 + Z ₀ ) = L / L ₀ Z _A0 + Z ₀ = (Z _A0 + ΔZ _A + Z ₀ ) · (L ₀ / L) Z ₀ (1−L ₀ / L) = − Z _A0 (1 −L ₀ / L) + ΔZ _A (L ₀ / L) ∴Z ₀ = −Z _A0 + ΔZ _A · (L ₀ / L) · {L / (L−L ₀ )} = − Z _A0 + ΔZ _A · L ₀ / (L−L ₀ ) (9) The correction position Z _{C based on the} point B of the cutter 2 is defined as Z _C = Z _C0 + ΔZ _C (10) where the moving amount is ΔZ _C. (Z _C + Z ₀ ) / (Z _C0 + Z ₀ ) = L / L ₀ (11) where Z _{C0 is a} known number and ΔZ _{C is an} unknown number.

From the equations (10) and (11), (Z _C0 + ΔZ _C + Z ₀ ) / (Z _C0 + Z ₀ ) = L / L ₀ Z _C0 + Z ₀ = (Z _C0 + ΔZ _C + Z ₀ ) · (L ₀ / L) ΔZ _C · (L ₀ / L) = Z _C0 (1−L ₀ / L) + Z ₀ (1−L ₀ / L) {ΔZ _C = Z _C0 {(L−L ₀ ) / L} · (L / L ₀ ) + Z ₀ Ｌ (L−L ₀ ) / L｝ · (L / L ₀ ) ΔZ _C = Z _C0 ｛(L−L ₀ ) / L ₀ ｝ + Z ₀ ｛(L−L ₀ ) / L ₀ ｝ ΔZ _C = (Z _C0 + Z ₀ ) · (L / L ₀ ) − (Z _C0 + Z ₀ ) (12) By substituting equation (9) into equation (12), ΔZ _C = Z _C0 {(L−L ₀ / L ₀ )} + {− Z _A0 + ΔZ _A (L ₀ / L−L ₀ )} (L−L ₀ / L ₀ ) = ΔZ _A + Z _C0 (L−L ₀ / L _{0) ) -Z A0 · (L-L} 0 / L 0)} ΔZ C = ΔZ A + (Z C0 -Z A0) {(L-L 0) / L 0} ··· 13) (10) and fixes the position of the formula (a direction parallel to the steel pipe central axis of the cutter 2 from 13) (z axis direction) can be determined.

With the above, the position of the cutter of the groove processing apparatus in the y-coordinate direction and the z-coordinate axis direction is determined, and the position of the cutter is controlled in accordance with the determined position to accurately follow the outer surface seam. Can be.

[0044]

Next, an embodiment of the present invention will be described. The cutter position control method of the present invention was implemented by the apparatus configuration shown in FIGS. The lower end of the spiral steel pipe 1 is supported by a support roller device 10. During the beveling operation, the spiral steel pipe is rotating, and the cutter 2 bevels the seam 12 at a fixed position while the position of the cutter 2 is corrected and controlled by the method of the present invention. CCD camera 3
And 4 are installed so as to be parallel to the central axis of the steel pipe (see FIG. 3).

The cameras 3 and 4 are moved in the direction of the y-coordinate axis by the camera driving devices 33 and 43, and their positions are detected by the camera position output devices 34 and 44. Before the start of the measurement, the y of the cameras 3 and 4 depends on the measurement conditions of the steel pipe.
The distance Y _{12 in the} coordinate axis direction and an appropriate position are set, and the position is moved to the position set by the position calculation device 6 and the camera position control device 9. When the support roller device 10 moves up and down in the y coordinate axis direction, the amount of movement is detected by the support roller position output device 11, and the positions of the cameras 3 and 4 are corrected.

In FIG. 1, the cutter position output device 22,
The camera position output devices 32 and 42 detect the positions of the cutter 2 and the cameras 3 and 4 in the z coordinate axis direction. The cutter driving device 21 and the camera driving devices 31 and 41 move the cutter 2 and the cameras 3 and 4 in the z coordinate axis direction. The image processing device 5 performs image processing on images from the cameras 3 and 4, detects seams, and calculates inclination angles m ₁ and m ₂ of the seams with respect to the z-coordinate axis. Data m ₁ and m ₂ calculated by the image processing device 5 and z of the cameras 3 and 4 from the camera position output devices 32 and 42
The position data in the coordinate axis direction is output to the steel pipe outer diameter calculation device 7, and the steel pipe outer diameter D and the seam spiral pitch L are calculated.
The position calculation device 6 calculates the positions of the cutter 2 in the y-coordinate axis direction and the positions of the cutters 2 and the cameras 3 and 4 in the z-coordinate axis from the outputs of the cutter position output devices 24 and 22 and the camera position output devices 32 and 42. calculate.

The data of the steel pipe outer diameter and the seam helical pitch L from the steel pipe outer diameter calculator 7 and the position data of the cutter 2 and the cameras 3 and 4 from the position calculator 6 are input to the cutter position controller 8. Calculate the cutter optimum position coordinates, and adjust the cutter driving devices 23 and 21 so that the outputs of the cutter position output devices 24 and 22 match the movement amount in the y-coordinate axis direction and the movement amount in the z-coordinate axis direction of the steel pipe. Camera position controller 9, the center of the area EA ₁ of the camera 3 and the images obtained from 4 to adjust the camera driving device 31 and 41 to be in the center of the image. As described above, the position of the cutter 2 is controlled exactly following the seam 12.

[0048]

As described above, according to the present invention, the groove of the outer surface seam of the spiral steel pipe can be accurately formed in accordance with the seam, and the steel pipe can be manufactured with uniform quality. Thus, an industrially useful effect is provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an apparatus configuration according to an embodiment of a method for controlling a cutter position of a spiral steel pipe groove processing apparatus of the present invention, in a state where a spiral steel pipe is viewed from the side.

FIG. 2 is a configuration diagram showing an apparatus configuration according to an embodiment of the present invention in a state in which a spiral steel pipe is in a cross section taken along line AA of FIG. 1;

FIG. 3 is an explanatory diagram showing a method of detecting a position and a seam inclination angle by a television camera according to an embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a method for calculating the outer diameter of the steel pipe and the seam spiral pitch according to one embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a method for determining a movement amount of a cutter position according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spiral steel pipe 2 Cutter 3 CCD camera 4 CCD camera 5 Image processing device 6 Position calculation device 7 Steel tube outer diameter calculation device 8 Cutter position control device 9 Camera position control device 10 Support roller device 11 Support roller position output device 12 Seams 21 and 23 Cutter driving device 31, 33, 41, 43 Camera driving device 22, 24 Cutter position output device 32, 34, 42, 44 Camera position output device

Claims (1)

[Claims] 1. A seam on an outer peripheral surface of a spiral steel pipe is picked up by a television camera, a position of the seam is detected by image processing based on a picked-up image signal, and a cutter of a groove processing device is made to follow the seam. In the method for controlling the cutter position of the spiral steel pipe beveling device, the height of the steel pipe supporting roller device that supports the spiral steel pipe in parallel to the central axis of the spiral steel pipe and always maintains a height of a fixed distance. Placing two television cameras, each of the two television cameras image the seam with the direction parallel to the central axis of the steel pipe as the abscissa axis and the radial direction of the spiral steel pipe as the ordinate axis, Two sets of seam positions of plane coordinates by the abscissa axis and the ordinate axis were detected by image processing based on a captured image signal, and were detected. Detecting the inclination angle of the seam formed by the seam and the direction parallel to the spiral steel pipe center axis at the seam position, and determining the spiral angle from the distance between the two sets of seam positions and the inclination angle of the seam; Calculating the outer diameter of the steel pipe and the helical pitch of the seam, calculating the control position of the cutter from the outer diameter of the spiral steel pipe and the helical pitch of the seam, and matching the position of the cutter with the control position of the cutter. A cutter position control method for a spiral steel pipe groove processing apparatus, comprising: