JPH0778411B2 - Plate dimension measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a dimension measuring device for highly accurately measuring the plate width of a continuous strip plate, or the shear length, plate width and squareness of a cut plate. is there.

[Conventional technology]

Currently, when measuring the plate material size with high accuracy, a camera with a high-resolution one-dimensional image sensor as a detector is installed on the camera movement stage and the camera is moved so as to detect the plate edge near the center bit of the camera. Then, the plate material dimension edge position from the reference point is measured from the camera position data from the stage origin and the plate material edge position data of the camera at that time, and the plate width, shear length, etc. are calculated. For the camera position from the reference point, one high-precision linear displacement detector is used to measure the moving amount of the camera moving stage.

FIG. 6 (a) shows an example of measuring a moving distance of a plate material by using a conventional high precision plate edge detecting mechanism.

The camera moving mechanism 1 is composed of a slide table 2, guide rails 3 and 3'for holding the slide table 2 slidably, and a feed screw 4 which is rotationally driven by a pulse motor 5.

A linear displacement detector 6 such as a magnescale is installed so that the current position of the slide table 2 from the origin position 6'of the detector can be measured. The output pulses A phase 14, B phase 15 and origin signal 16 from the Magnescale are input to the up / down counter 7a via the direction discriminating circuit 7 to display the slide table position, that is, the camera position on the position display section 7b. It The plate material 9 is illuminated by the light source 10.

As shown in the figure, a camera 8 having a one-dimensional image sensor as a detector is fixed directly on a slide table, and a straight line passing through the lens center at that time is defined as a _{0 to} a ₀ ′.

At the initial position of the plate edge, the distance Δl between the origin 6 ′ of the magnescale 6 and the camera center lines a _{0 to} a ₀ ′ is as close to the origin 6 ′ as possible. The edge portion 9'of the plate material 9 is set at a position detected by the central bit of the one-dimensional image sensor camera 8. At this time, in the video signal 11 of the one-dimensional image sensor camera, the bright field level and the dark field level are switched by the central bit of the sensor as shown in FIG. 6 (b). Next, the distance between the camera 8 and the plate edge 9 '
When it is moved ₁ l, the center axis of the camera is tilted due to the bending of the guide rails 3, 3 '. The central axis of the camera at this time
Let a _{1 to} a ₁ ′. The moving camera center axes a _{1 to} a ₁ ′ are inclined at an angle θ ₁ with respect to the initial camera axis center a _{0 to} a ₀ ′, and the camera center axes a _{1 to} a ₁ ′ are the visual field position and the plate material edge portion 9 ′. Will be away from ΔX. That is, the image of the plate material edge portion 9'formed on the one-dimensional image sensor is displaced from the sensor central bit by (ΔX / resolution of the camera sensor at the visual field position) bits, and the video signal 12 is changed to the sixth signal. It is shown in FIG.

Combining Magnescale and image sensor data, M _D6 + K ₁ {(camera sensor edge position data) -1/2
(Total number of sensor bits)} K ₂ (1) M _D6 : Magnescale data K ₁ : Magnescale resolution K ₂ : Camera sensor resolution at the visual field position Equation (1) is the magnescale origin 6'of the plate edge. Represents the position relative to. However, the tilt θ of the camera center axis
The deviation amount from the center bit of the sensor detecting the plate material edge portion 9'by ₁ becomes a measurement error as it is.

[Problems to be Solved by the Invention]

As described above, the linearity of the camera moving mechanism poses a problem, but in order to improve the mechanical accuracy, it is necessary to increase the rigidity of the entire mechanical section, which causes the problem of increasing the size and cost of the device.

Further, when the camera moving stage has a bend, the camera field of view shifts left and right (or front and back), which results in a measurement error.

On the other hand, recently, there is a strong demand for improving the dimensional accuracy of thin steel plates, and thus the accuracy of the measuring device is required to be improved.

Therefore, the present invention has been developed in view of the problems and demands in the above-mentioned conventional technique, and an error caused by the non-linearity of the camera moving stage is corrected by a plurality of high-accuracy linear displacement detectors. Position (up and down position of camera)
It is an object of the present invention to provide a plate material dimension measuring device capable of calculating and correcting the tilt of the camera by measuring the.

[Means for Solving the Problems]

The plate material size measuring apparatus of the present invention is a plate material size measuring apparatus equipped with a camera having a one-dimensional image sensor as a detector and a camera moving mechanism for moving the camera to a measurement position. A feature is that a scale is provided and the measured value is corrected by using the difference between the measured values between the scales.

Further, as one correction method, a linear displacement detector provided in the camera moving mechanism is used to detect the inclination of the camera to correct the measurement error.

[Action]

FIG. 1 exemplifies the case of measuring the moving distance of a plate material.

As shown in FIG. 1, a camera which uses a one-dimensional image sensor due to the bending of the guide rails 3 and 3'as a detector by newly providing a linear displacement detector such as a magnescale for detecting the inclination of the central axis of the camera The inclination of 8 is measured and corrected.

The principle will be described with reference to FIG.

First, the camera moving mechanism 1 moves the camera 8 from the backward limit on the left side to a point Δl slightly passing through the magnet scale origins 6'and 13 '. At that time, the plate material edge portion 9'is also positioned so as to form an image on the central bit of the camera. At this time, the moving distance data Δl with respect to the origins of the two magnet scales 6 and 13 can be regarded as equal since they are the closest to the origins. The camera center axis at this position is represented by a _{0 to} a ₀ ′.

If the display value on the Magnescale 6 is lx and the display value on the Magnescale 13 is l'x when the camera is moved from that position by l ₁ , the camera center axis at this position is a _{1 to} a ₁ ′. Then, both magnescale 6 and the mounting pitch camera center axis a ₁ ~a ₁ between P ₁ of 13 'a ₀ ~a _0' to, (l _X -
This means that a tilt of l' _X ) K ₁ mm is generated.

P _1: magnescale 6 and 13 of the mounting pitch P _2: When magnescale 6 and the camera view position distance, deviation in the camera field position caused by the inclination of the camera central _{axis, (l X -l 'X)} P2 The error becomes larger as / P1 becomes and the visual field position becomes farther.

This device corrects by adding or subtracting this deviation to the measurement data.

That is, the salt calculation formula for correction is expressed by the following formula (2).

_{{L X + (l X -l} 'X) P2 / P1} K 1 + {( plate edge position data of the camera) -1/2 · (sensors the total number of bits)} K ₂ ......
(2) [Examples] Examples of the present invention will be described below.

(First Embodiment) A case where the first embodiment of the present invention is applied to a high-accuracy plate width measuring device will be described with reference to FIGS. 2 and 3.

Similar to the above, two camera moving mechanisms 21 and 41 having cameras 28 and 48 having one-dimensional image sensors as detectors are installed.
Is fixed to a base 19 having high rigidity, and is arranged in a counter groove with respect to the center of the line on which the sheet-shaped steel sheet material as the material to be measured is conveyed.

At this time, the distance between the magnet scale origins, that is, the origin 26 '
The space of 46 'is set slightly larger than the maximum measuring range.

The level at which the sheet steel sheet flows, that is, the pass line 17 is indicated by a two-dot chain line.

The illuminating fluorescent lamp 20 is installed on the side opposite to the camera with respect to the pass line 17. For the calibration plate 18, a measurement plate that is as close as possible to the measurement range is prepared, and is installed on the pass line at a right angle to the flow direction of the line and directly below the camera for calibration.

The camera moving mechanism is controlled as follows by a controller (not shown).

When the return-to-origin push button switch on the operation panel is turned on, both cameras retract once until the backward limit sensors 26 ″ and 46 ″ operate, and then move forward and stop when they pass the origin sensors 26 ′ and 46 ′. Complete the dispensing operation.

The position display of both cameras at this time is set to 0. That is, the moving distance of each camera based on this position is Magnescale 26, 27.
And 46,47.

Next, when the measurement start push button switch is turned on, the camera will move to the calibration plate.
Until the 18 enters the field of view, it is sent inward at high speed by the pulse motors 25 and 45 via the ball screws 24 and 44, and when the calibration plate 18 enters the field of view, it switches to low speed and the central bits of the cameras 28 and 48 are covered. When the measurement object is detected, that is, when the video signal level changes from the dark field level to the bright field level at the central bit position (see FIG. 6 (b)), the operation is stopped. In this case, since the position where the camera stopped is the immediate vicinity of the magnescale origins 26 'and 46', the influence of bending of the guide rail, etc. can be ignored, so the display values of the magnescales 26, 27 and 46, 47 match. . The cameras are installed on the moving stands 22 and 42.

FIG. 3 shows the signal flow from each detector. Camera 28,4
Along with the movement of 8, the pulse train generated from the magnescales 26, 27 and 46, 47 determines the moving direction by the phase determination circuits 31, 32 and 31a, 32a, and the up / down counters 33, 34 and 33a, 34a up. The number of pulses proportional to the camera moving distance is input as an input or a down input. That is,
The contents of the up / down counters 33, 34 and 33a, 34a are always the number of pulses proportional to the camera position from the origins 26'27 'and 46', 47 '. The contents of each counter are display 3
It is displayed on 3 ', 34' and 33a, 34a '.

In FIG. 3, 35, 35a, 36, 36a, 37, 37a are video signals, 51
Is an inter-origin setting device, 52 is a computing device, 53 is a display device, 54 is a converter, and 55 is a recorder.

In this device, the resolution of the magnescales 26, 27 and 46, 47 is set to 1 pulse = 1 μm.

The current positions of the cameras 28 and 48 are input to the microcomputer system 52 as parallel data represented by up / down counter data 33 ″, 34 ″ and 33a ″, 34a ″.

The microcomputer system 52 uses the data from the respective detectors, that is, the plate edge position data 37 ', 37a' of both cameras 28 and 48, and the magnet scale data 33 ", 34" and 33a ", 34a" for detecting the camera movement position and the data. Magnescale origin 26 ', 4
The data 51 'of the 6'-interval distance setting device 51, that is, L _{0 and the} like in FIG. 2 are calculated by the following equation (3) to calculate the plate width. The measurement plate width data 52 ′ and the difference 52 ″ between the set plate width data and the measured plate width data are digitally displayed on the display 53. The difference 52 ″ between the set plate width data and the measured plate width data is the D / A converter. Five
It is recorded in the recorder 55 as an analog signal by 4.

Measurement plate width W = L ₀ −l _X1 −l _X2 (3) where l _X1 is the right edge position of the plate to be measured with respect to the magnescale origin of the left camera movement mechanism, and l _X1 = {l _D26
＋ (l _D26 −l _D27 ) P2 / P1} K ₁ ＋ {(right camera edge position data) −1/2 ・ (total number of sensor bits)} K ₂ l _X2 is the target for the magnescale origin of the left camera moving mechanism. At the left edge position of the measuring plate, l _X2 = {l _D46 + (l _D46 -l _D47 ) P2 / P1} K ₁ + {(left camera edge position data) -1/2 · (total number of sensor bits)} K
₂ P ₁ : Mounting distance between Magnescale 26 and 27 or 46 and 47 P ₂ : Distance between Magnescale 26 or 46 and pass line K ₁ : Resolution of Magnescale K ₂ : Resolution at field of view of one-dimensional camera sensor L ₀ : Origin distance of Magnescale 26 and 46 Here, the distance between origins L ₀ can be set to any value by the origin setter 51 because there is a difference between design values due to mechanical mounting conditions. The calibration plate 18 and the measured value, that is, the value displayed on the plate width display, matches the distance L ₀ between the origins so that the measured value L ₁ matches the measured length L _{1 of the} calibration plate.
Calibration is completed by setting with 51.

After that, the measurement can be performed for any plate width, and the error due to the non-linearity of the guide rail is corrected by the equation (3), and high-precision measurement is possible.

The measurement accuracy of this device is ± 0.02mm in the measurement range of 400-1600mm.

(Second Embodiment) Next, an embodiment in which the second embodiment of the present invention is adopted in a right angle measuring device for a cut plate material will be described below.

In FIG. 4 (a), when measuring the squareness of the cutting plate member 74 indicated by the chain double-dashed line, the cutting plate member 74 is installed on the surface plate 71 for measurement. The side 76 of the cut plate member 74 is applied to the positioning stopper 73.

One side 72 on the surface plate is a raised edge and is finished with high accuracy as a reference side during measurement. Side 75 of cutting board 74
While pressing the plate against the base side 72 of the platen, slide it to the left in the figure and press the side 76 against the stopper 73.
Measure the squareness of sides 76 and 77 with reference to side 75. 78,79
Is a camera that uses a one-dimensional image sensor as a detector and is fixed so that the center of the camera is aligned with the right side point 73 'of the stopper 73.

When the sides 75 and 76 are completely at right angles, the edge position data of the side 76 of the cutting plate material 74 detected by the cameras 78 and 79 have the same value.
The definition of squareness is stopper 73 as shown in Fig. 4 (b).
Straight line C drawn from the right side point 73 'of the
The arithmetic expression expressed by the deviation amount of the side 76 with respect to C ′ and the deviation length between the pitches P is the following expression (4): {(camera 79 edge data) − (camera 78 edge data)} K ₂
...... (4) K _2: pitch P in resolution present embodiment in the camera field of view position is a 600 mm, it is not always necessary to match the camera mounting pitch, it is also possible to calculate a proportional calculation.

Since the position of the side 77 moves left and right due to the shear length of the cut plate material, the cameras 80 and 81 are configured to be movable by the camera moving mechanism 82. In this case, in the prior art, due to the bending of the guide rail of the camera moving mechanism, the inclination of the camera center line changes depending on the camera position, as in the previous example, causing a measurement error.

FIG. 5 shows a camera moving mechanism used in the perpendicularity meter according to the present invention.

Since the camera moving mechanism moves the two one-dimensional cameras at the same time, firstly, the two cameras 80 and 81 are the causes of error.
The straight angle between the straight line 101 connecting the centers of the two and the center line 103 of the camera moving mechanism 82 changes depending on the camera stop position. The center line 101 connecting both cameras at the calibration position is 10 at the camera stop position after the movement.
It is to generate a slope like 1a or 101b.

The second cause of error is that the center line 102 or 103 of each camera is inclined with respect to the camera center line 102 or 103 at the time of calibration like 102a, 102b or 103a, 103b.

In this device, Magnescales 83 and 84 are provided for the purpose of measuring the inclination of the center line 101 with respect to the first error generating factor, and each camera position is calculated from each Magnescale data M _D83 , M _D84 to perform correction. .

The position of the camera 80 with respect to the origin 83 'of the magnescale 83 is calculated by the following equation (5).

{M _D83 − (M _D83 −M _D84 ) × P5 / P4} K ₁ (5) Further, the position of the camera 81 with respect to the origin 84 ′ of the _{magnescale 84} is calculated by the following equation (6).

{M _D84 − (M _D84 −M _D83 ) × P5 / P4} K ₁ (6) Where, P ₄ is the installation distance between the _magnescales 83 and 84 P ₅ is the installation distance between the cameras 80 and 81 The shift amount at the visual field positions of the cameras 80 and 81 with respect to the error generation factor is expressed by the equations (7) and (8).

Magnescales placed in parallel with each of the Magnescales 83 and 85 to detect the inflection at the center of the camera
Using 84 and 86 of the magnetic scale data _{M D85 · M D86, K 1} (M D83 -M D85) × P2 / P1 ...... (7) K 1 (M D84 -M D86) × P2 / P1 ...... ( 8) Where, P ₁ is the distance between the magnescales 83 and 85 and 84 and 86 P _{2 is} the distance between the magnescales 84 and 85 and the surface of the plate (field of view) to be measured. The error due to the non-linearity of the camera moving mechanism is corrected by calculating the plate edge position data by the following equations (9) and (10).

_{{M D83 - (M D83 -M} D84) × P5 / P4 + (M D83 -M D85) × P2 /
P1} K ₁ + {(camera 80 edge position data) -1/2 (sensor total number of _{bits)} K 2 ...... (9)} {M D84 - (M D84 -M D83) × P5 / P4 + (M D84 - M _D86 ) × P2 /
P1} K ₁ + {(camera 81 edge position data) -1/2 (total number of sensor bits)} K ₂ (10) In this device, P ₄ = 600 mm, P ₅ = 400 mm, K ₁ = 1 μm,
When K ₂ = 2 μm is set, the squareness of the cutting plate material 74 with respect to the side 75 can be measured with an accuracy of ± 0.01 / 600.

〔The invention's effect〕

As described above, according to the present invention, even for a long plate material, the movement distance and the plate length can be measured again.
Even with a wide plate exceeding 1 m, it became possible to automatically measure the plate width within an error of 10 μm in a short time.

Further, according to the present invention, the squareness of a large plate material is 0.01 / 600.
It became possible to do it automatically within a short time due to internal error.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of the present invention, FIGS. 2 and 3 show a first embodiment of the present invention, FIG. 2 is a block diagram of the apparatus, FIG. 3 is the same block diagram, FIG. 4 and FIG. FIG. 5 shows a second embodiment of the present invention, FIG. 4a is a block diagram of the apparatus, FIG. 4b is the same explanatory view, and FIGS. 5a, 5b and 5c are cameras used for a goniometer. Plan view, front view and side view of the moving mechanism, FIG. 6 a, b
And c are explanatory views of a conventional device. 1,21,41,82 …… Camera moving mechanism 2,22,42 …… Slide table 8,28,48,80,81 …… Camera with one-dimensional image sensor as detector 6,13,26,27, 46,47,83,84,85,86 …… Linear displacement detection scale 9,18,74 …… Measured plate material

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenichi Iwanaga 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) In-house Takato Furukawa 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Steel Tube Co., Ltd. (72) Inventor Atsushi Takekoshi 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Tube Co., Ltd.

Claims (1)

[Claims] 1. A moving mechanism provided with two cameras each having a one-dimensional image sensor as a detector, and moving so that each camera detects both edges of a measuring object at a central bit of the cameras or a bit near the central bit. In a plate material size measuring device for detecting and calculating the plate material size from the moving distance from the origin position of each moving mechanism and the edge detection bit of the camera,
A plurality of linear displacement detectors are provided in parallel to the moving direction of the camera moving slide table provided in the camera moving mechanism, and the difference between the measured values of both detectors with respect to the camera moving position and the side close to the object to be measured. It is characterized in that the detection error caused by the tilt of the camera caused by the bending of the slide table is corrected by the product of the detector and the ratio of the distance to the object divided by the mounting interval of both detectors. Plate material size measuring device.