JPH06286977A - Position detecting device for steel sheet coil - Google Patents

Abstract

PURPOSE:To provide a position detecting device for a steel sheet coil which is designed to reduce size and weight, facilitate operation and maintenance, eliminate a need for energization for a long time, provide an increased life, and improve economical efficiency. CONSTITUTION:The trolley of an overhead traveling crane is provided with two scanning mirrors 6 and 6 to convert spot light of a semiconductor laser 3 into primary slit light paralleling the traveling direction or the traverse direction of an overhead traveling crane for handling a coil; and a plurality of television cameras 2 to photograph slit light with which a steel sheet coil is irradiated. Further, the trolley comprises an A/D converter 7 to convert the image signal of the television camera 2 into a digital signal; a binary-coding device 9 to fetch only a laser image from digitized image data; a coordinate converting device 10 to convert the secondary coordinate of a laser image on image data into position data in an actual three-dimensional space; and a computing device 11 to substitute three-dimensional position data in a radial direction on the steel sheet coil for an equation of a circle and calculate a central position in the radial direction of the coil and a radius by effecting a solution through a minimum involution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position detecting device for a steel plate coil or the like which is applied to automatic (unmanned) operation of an overhead crane for coil handling in a steel mill.

[0002]

2. Description of the Related Art A coil obtained by winding a thin steel plate into a roll is stored in a warehouse during a waiting time before shipment at each steel mill. Recently, in order to automate work in this coil warehouse, automatic (unmanned) operation of an overhead crane is being promoted, which makes it easy to manage work that was difficult in the past and improves productivity and homogenization. Furthermore, the large effect that the worker can be released from the work in the bad environment, the dangerous work, and the simple work is intended. In this case, a problem in automating the overhead crane is a coil handling work which is conventionally carried out by an operator on the crane machine. In other words, in the handling work, unless the precise location of the target coil and the relative positional relationship between the coil position and the crane in the location are clarified, mishandling or load shake may occur and an accident may occur. The problem is that they are tied together. When a trailer is used as a method of storing the coil in the warehouse, the stop position of the trailer fluctuates, so that the control accuracy of the coil position deteriorates. From the above situation,
A sensor for accurately providing the position of a predetermined coil is required. As such a coil position detecting device, Japanese Patent Application No.
The invention of No. 2-243715 has been proposed. This coil position detection device uses the cylindrical shape of the coil. By devising the arrangement of the two TV cameras and the light source, the height distribution in the radial direction and width direction of the coil can be calculated by the triangulation method. The measurement is performed to calculate the center position, radius and width of the coil. Then, after the overhead crane is roughly positioned at the preset trailer stop position, the coil position is detected and accurate positioning is performed.

That is, FIG. 3 is a layout diagram of height detection by the triangulation method, and the height distribution of the coil 4 is obtained by mounting the TV cameras 1 and 2 and the laser light source (including scanning mirror) 3 on the trolley 5 of the overhead crane. It is installed and measures by the principle of triangulation. FIG. 4 shows a principle diagram (radial direction) of three-dimensional position detection by the triangulation method, and the point (x, y, z) on the coil 4 on which the laser beam hits corresponds to the TV.
When the position of the laser light on the screen of the camera is (i, j), it is given by the following equation. x = x component of the position of the laser light source (trolley) ... (1) y = h ₀ -h ... (2) z = cos α√ (c ² + h ² ). {[(G / 2) -i] / (g / 2)} tan (γ / 2) ··· (3) h = ctan (θ-α) ···· (4) α = tan ^-1 {[tan (β / 2) × [(g / 2) −j] / (g / 2)]} (5)

Here, h ₀ : Distance between the ground of the TV camera C: Distance between the TV camera and laser light source (scanning mirror) θ: Mounting angle of the TV camera h: Detection distance α: Laser with respect to the optical axis of the TV camera Incident angle of light β: View angle of TV camera in vertical (J) direction γ: View angle of TV camera in vertical (I) direction g: Horizontal or vertical number of pixels of image scale Therefore, by rotating the scanning mirror and irradiating the coil surface while moving the laser spot light parallel to the z-axis, the height distribution in the radial direction of the coil (three-dimensional position) can be obtained from the equations (1) to (5). ) Is obtained. Specifically, TV
If the absolute value is calculated between frames for the image data (kth frame) taken by the camera 1 and the image data (k-1th frame) one frame before, the laser spot light will always move due to the rotation of the scanning mirror. Therefore, only the laser spot light on the image data can be extracted. When this is repeated and integrated, laser spot images are connected and a laser slit image can be synthesized. Therefore, if the coordinates of each point on the laser slit image are transformed by the equations (1) to (5), the radial height distribution of the coil surface (three-dimensional position)
Is obtained. Similarly, install the TV camera 2 on the z-axis,
By irradiating the coil surface while rotating the scanning mirror to move the laser spot light parallel to the x-axis, the height distribution (three-dimensional position) in the width direction of the coil 4 can be obtained.

FIG. 5 shows the principle of detecting the position of the coil 4. For convenience of explanation, the ground directly under the laser light source (scanning mirror) on the trolley is the origin O, and the x-axis is parallel to the traverse trajectory of the overhead crane. , X axis, y axis parallel to the height direction and z axis parallel to the running track are set. Also,
As shown in the figure, the coil 4 is on the central turning side (width direction).
Are arranged in parallel with the x-axis, and the radial direction is arranged in a direction parallel with the z-axis. The same figure (A) has shown the irradiation position of the laser beam in xz plane. In addition, FIG.
(C) is an example of the result of measuring the height distribution of the coil surface parallel to the x-axis and the z-axis. From the figure (C), coil 4
The width D and the center position B of the width are given by the following expressions. D = L ·················· (6) B = B (x b, y b, z b) ············ ( 7) Further, since the height data in the radial direction in FIG. 7B is the data on the outer circumference of the coil 4, the following circle equation is satisfied. ^{_{(Y 1 -y a) 2 +}} (z 1 -z a) 2 = r 2 ····· (8)

Here, y ₁ and z ₁ are the height data of the coil surface in the radial direction, y _a and z _a are the center coordinates of the circle, and r is the radius of the coil 4. Accordingly, the center position of the circle (y _a and z _a) defining the equation _{(8), f = (y i -y a} ) 2 + (z i -z a) 2 = r 2 ··· (9) Then, y _a to minimize the evaluation function F in the following equation, z _a, be determined to r, they seek "y _a, z
_a , r ”. F = Σ (i = 1~n) {(y i -y a) 2 + (z i -z a) 2 = r 2} → min ··· (10) formula (10) is more than 3 points If the position coordinates (y _i , z _i ) on the circumference of are given, they can be solved by the Newton-Raphson method, for example. From the above, the center position G (x _g , y _g , z _g ) of the coil 4, the radius r and the width D are given by the following equations. _{G (x g = x b ·······} (11) y g = y a z g = z a) r = r ······· (12) D = L ······ (13) Therefore, if the handling center of the crane is associated with the origin O of the coordinate system, each of the above values can be used as the crane control amount.

[0007]

As described above,
The conventional coil position detection device is a very useful device because it can detect the position information of the coil required for automating the overhead crane for coil handling without contact and accurately. However, when this type of coil position detection device is mounted on an overhead crane for coil handling and operated, since a He-Ne laser is adopted as a light source, there are the following problems.

First, the length of the He-Ne laser is 1 m.
Because of the long length, it is necessary to take special measures such as creating a special jig when mounting it on the trolley of an overhead crane. In addition, because of its large size, it is difficult to carry.
Further, the He-Ne laser has a structure in which a resonance phenomenon occurs between two reflection mirrors to increase the optical power, and therefore the power is essentially reduced when the optical axis is deviated. Therefore, if the power is lowered for some reason, the coil position detection device will not operate normally, and thus the work of adjusting the optical axis becomes necessary. As described above, He-
The Ne laser is a structural problem and has a problem that maintenance is very poor.

Second, since the He-Ne laser requires about 1 hour of energization to reach the maximum power after the power is turned on, it takes 24 hours to keep the system ready for use for 24 hours. Energization is required. This is He
-In connection with the life of the Ne laser, this method requires replacement of the laser in about 1 year. As described above, the He-Ne laser has a problem in terms of life and energy saving (operating method).

The present invention has been proposed in view of the above circumstances, and it is small and lightweight, easy to operate and maintain, and long-life economical steel plate coil position or the like that does not require energization for a long time. An object is to provide a detection device.

[0011]

To this end, the present invention provides a semiconductor laser and two units for converting the spot light of the semiconductor laser into a one-dimensional slit light parallel to the traveling direction or the transverse direction of an overhead crane for coil handling. Scanning mirror and multiple TV cameras for photographing the slit light irradiated on the steel plate coil are installed on the trolley of the same overhead crane, etc., and the A / D for digitizing the video signal of the TV camera.
A converter, a binarization device that extracts only a laser image from digitized image data, and a coordinate conversion device that converts the two-dimensional coordinates of the laser image on the image data into actual three-dimensional position data. An arithmetic unit that substitutes the three-dimensional position data in the radial direction on the steel plate coil into the equation of the circle and solves it by the least squares method to calculate the center position and radius in the coil radial direction, and the laser image in the width direction on the same steel plate coil. An end point detection device that detects the positions of both ends in the width direction on the steel plate coil, and after coordinate conversion to three-dimensional position data in the actual space by the coordinate conversion device, calculates the center position and width in the width direction of the steel plate coil. It is characterized by having and.

[0012]

According to this structure, the semiconductor laser is used as the light source, and the following effects are obtained. That is,
Compared with the conventional He-Ne laser, which is a light source, its size is 1/10 or less, and it is small and lightweight, so there is no need to secure a mounting space or adjust the optical axis of the discharge tube, making it easy to carry and maintain. improves. Further, since the He-Ne laser requires about 1 hour of energization to reach the maximum power after the power is turned on, 24 hours of energization is required to keep the system ready for use for 24 hours. . This is related to the life of the He-Ne laser, which requires about 1 year to replace the laser. On the other hand, the semiconductor laser reaches the maximum power immediately after the power is turned on, so the system is
Even if it is ready to be used any time, it does not need to be energized for 24 hours and can be used immediately if energization is started when necessary. Therefore, the life of the laser is expected to be about 5 years or more, which has two effects of energy saving and cost saving.

[0013]

1 is a block diagram showing a steel plate coil position detecting device, FIG. 2 is a partially enlarged view showing a binarizing device in FIG.
FIG. 3 is an overall perspective view of the device of the present invention, which is macroscopically the same as the conventional overall perspective view.

In the above figure, in detecting the coil position, an arbitrary position on the ground in the coil yard is set as an origin O, a direction parallel to the transverse direction is x-axis, a direction parallel to the traveling direction is z-axis, and a winding direction is parallel. X with the y-axis in any direction
An yz orthogonal coordinate system is set.

In FIGS. 1 and 2, 1 and 2 are TV cameras, 3 is a semiconductor laser, and 6 is two scanning mirrors. The laser light is reciprocated in parallel with the x-axis or the z-axis by the two scanning mirrors 6 and the semiconductor laser 3. The controller 13 selects the x-axis and the z-axis. For convenience of explanation, the TV camera 1 captures an image for measuring the radial height distribution of the coil, and the TV camera 2
Shall capture an image for measuring the height distribution of the coil in the width direction. Reference numeral 7 is an A / D converter for A / D converting the video signals of the TV cameras 1 and 2.

Reference numeral 9 denotes a binarizing device. As shown in FIG. 2, the binarizing device 9 delays the image data A / D converted by the A / D converter 7 by one frame.
1. Absolute value calculation circuit 2 for obtaining the difference between the image data of the k-th frame output from the A / D converter 7 and the image data of the (k-1) th frame delayed by one frame by the delay circuit 21.
2. A binarization circuit 23 that binarizes the output data of the arithmetic circuit 22 with a fixed threshold value, and an integration circuit 24 that integrates the binarized output for n frames, and synthesizes and extracts a laser slit image. Output to the end point detection device 12.

Further, in FIG. 1, 10 is a coordinate conversion device for calculating the position (x, y, z) of the xyz coordinate system of the actual space from the position (i, j) of one point on the image data, and 11 is An arithmetic unit for calculating the center position and radius of the coil from the three-dimensional position coordinate data of three or more points in the radial direction of the coil according to the principles shown in the equations (6) and (10). Is an end point detection device for detecting the positions of both ends of the coil from the laser slit image of FIG. Reference numeral 13 denotes a controller, which controls the operations of the TV cameras 1 and 2, the laser light source 3, and the scanning mirror 6, and the end point detection device 12 and the arithmetic device 11
Calculation result of (coil center of gravity position G (x _g , y _g , z _g )
And a width D and a radius r, and outputs a control signal for controlling the crane operation.

As shown in FIG. 3, the semiconductor laser 3, the two scanning mirrors 6 and the TV cameras 1 and 2 are set on the trolley 5 of the crane or a traverse device which can traverse independently of the crane. Now, the operation of the present apparatus will be described on the assumption that the trolley 5 is roughly positioned above the preset coil to be handled. First, the two scanning mirrors 6 are controlled so that the laser beam reciprocates on the coil in parallel with the radial direction of the coil. This is taken with the TV camera 1, and the video signal is A /
A / D conversion is performed by the D converter 7. Further, in the binarization device 9, after calculating the absolute value of the difference between the image data of the k-th frame and the image data of the (k-1) th frame, it is binarized by a fixed threshold value and integrated for n frames (actually, , Calculate the logical sum)
Then, the laser slit image in the radial direction can be synthesized and extracted (image data 1 in FIG. 3). This is the coordinate conversion device 10
After conversion into position data in the xyz coordinate system with, the arithmetic unit 11 calculates the center position (y ₀ , y ₀ ,
z ₀ ) and the radius r are calculated and sent to the controller 13.

After receiving the above data, the controller 13 controls the two scanning mirrors 6 so that the laser beam reciprocates on the coil 4 in parallel with the width direction of the coil. This is photographed by the TV camera 2, and the video signal is A / D converted by the A / D converter 7. Furthermore, in the binarizing device 9, after calculating the absolute value of the difference between the k-th frame and the image data of the (k-1) th frame, it is binarized with a fixed threshold value and integrated by n frames, A laser slit image in the width direction is synthesized and extracted (image data 2 in FIG. 3). The end point detection device 12 detects the positions of both ends on the coil 4, and the coordinate conversion device 10 converts the positions into position data in the xyz coordinate system, and the width D of the coil 4 and the center position x _{0 in the} width direction.
Is calculated and sent to the controller 13. After receiving the above data, the controller 13 outputs a crane control signal.

[0020]

According to the device of the present invention as described above, the following effects are obtained by applying the semiconductor laser to the light source, as compared with the conventional coil position detecting device. That is,
Compared with the conventional He-Ne laser, which is a light source, the size is 1/10 or less, and it is small and lightweight, so there is no need to secure a mounting space or adjust the optical axis of the discharge tube, making it easy to carry and maintain. Is improved. Furthermore, He-N
Since the e-laser requires about 1 hour of energization to reach the maximum power after the power is turned on, 24 hours of energization is required to keep the system ready for use for 24 hours. This is related to the life of the He-Ne laser, which requires about 1 year to replace the laser. On the other hand, since the semiconductor laser reaches the maximum power immediately after the power is turned on, even if the system is ready to be used 24 hours a day, it is not necessary to energize it for 24 hours, and energization is started when necessary. You can use it immediately. Therefore, the life of the laser is expected to be about 5 years or more, which has two effects of energy saving and cost saving.

In short, according to the present invention, a semiconductor laser, and two scanning mirrors for converting spot light of the semiconductor laser into one-dimensional slit light parallel to the traveling direction or the transverse direction of the coil handling ceiling crane, Installed on a trolley of the same overhead crane with multiple TV cameras that shoot the slit light radiated on the steel plate coil
An A / D converter that digitizes the video signal of the camera, a binarization device that extracts only the laser image from the digitized image data, and the two-dimensional coordinates of the laser image on the image data in the actual three-dimensional space. A coordinate transformation device for transforming into position data, and a computing device for substituting the radial three-dimensional position data on the steel plate coil into a circle equation and solving it by the least square method to calculate the center position and radius in the coil radial direction. Detecting the positions of both ends in the width direction on the steel plate coil from the laser image in the width direction on the steel plate coil, and after performing coordinate conversion to three-dimensional position data in the actual space with the coordinate conversion device, the width direction of the steel plate coil Since it is equipped with an end point detection device that calculates the center position and width of the, it is small and lightweight, easy to operate and maintain,
The present invention is extremely useful industrially because a position detecting device for a long-life economical steel plate coil or the like that does not require long-time energization is obtained.

[Brief description of drawings]

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

FIG. 2 is a partially enlarged view showing the binarizing device in FIG.

FIG. 3 is a macroscopic overall perspective view of the device of the present invention, which is the same as an overall perspective view showing a conventional steel coil position detecting device.

4A and 4B are principle diagrams of three-dimensional position detection by the triangulation method in FIG. 3, where FIG. 4A is a front view, FIG. 4B is a side view, and FIG. Is.

5 is an explanatory diagram of acquired data according to FIG. 4. FIG.

[Explanation of symbols]

 1 TV camera 2 TV camera 3 Semiconductor laser (laser light source) 4 Steel plate coil 5 Trolley 6 Scanning mirror 7 A / D converter 9 Binarization device 10 Coordinate conversion device 11 Arithmetic device 12 Endpoint detection device 13 Controller 21 Delay circuit 22 Arithmetic operation Circuit 23 binarization circuit 24 integration circuit

Claims (1)

[Claims] 1. A semiconductor laser, two scanning mirrors for converting spot light of the semiconductor laser into one-dimensional slit light parallel to a traveling direction or a transverse direction of an overhead crane for coil handling, and a steel plate coil. A plurality of TV cameras for shooting slit light are installed in the trolley of the same overhead crane, and only the laser image is extracted from the A / D converter that digitizes the video signal of the TV camera and the digitized image data. A binarization device, a coordinate transformation device that transforms the two-dimensional coordinates of the laser image on the image data into actual three-dimensional position data, and a circle equation for the three-dimensional radial position data on the steel plate coil. And a calculation device that solves by the least squares method to calculate the center position and radius in the coil radial direction, and a laser image in the width direction on the same steel plate coil on the same steel plate coil. After detecting the positions of both ends in the width direction and converting the coordinates into the three-dimensional position data of the actual space by the coordinate conversion device, an end point detection device for calculating the widthwise center position and width of the steel plate coil is provided. Position detection device for characteristic steel plate coils.