JPS59197813A - Attitude measuring method by optical cutting - Google Patents

Abstract

PURPOSE:To measure an attitude of a work by a mutual relation of an obtained cut image by inclining mutually two slit-like lights and irradiating them to the work. CONSTITUTION:This method is constituted so that slit lights 4a, 4b from a light source are irradiated to a work 2 through projecting windows 5, 6 provided on a sensor body 1, and the slit lights 4a, 4b are inclined by a necessary angle, respectively, against the vertical surface and crossed in the lower part of the sensor. Also, a lens 7 is provided on an intermediate position of the projecting windows 5, 6 of the lower face of the sensor body 1, so that cut images 8a, 8b can be formed on an image pickup element 9. The cut image 8a, 8b obtained by the sensor measure an attitude of a work by a correlation to these two cut images 8a, 8b. That is to say, a distance DW of the sensor body 1 and the work 2, an angle phiS of the center line in the H direction of the sensor body 1 and a weld line, a shift (ld) of the center of the sensor body 1 and the center of the work, an inclination PSIS of a vertical line Z and the weld line, and an inclination alpha of the work in the right angle direction to the vertical line Z and the weld line can be measured, and a three-dimensional attitude of the work 2 measured.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an attitude measurement method using optical cutting, which measures the attitude, etc. of an object to be measured by irradiating the object with a slit-shaped light beam and using a cut image obtained on the object to be measured. .

Currently, a method using optical cutting is known as a non-contact measurement method.

This refers to a slit-shaped light ray (a flat ray, a point ray arranged on the same plane, a - point ray scanned in the same plane) to the object to be measured (hereinafter referred to as a workpiece). The cut image obtained on the object to be measured is observed obliquely through the slit-like beam, and the shape of the cut image is observed to determine the shape of the workpiece.

However, in the conventional light cutting method using a slit-shaped beam,
The shape of the cut image changes due to the mutual relationship between the workpiece and the slit-shaped light beam, for example, if the workpiece is tilted with respect to the light beam, making it impossible to perform accurate measurements and the amount of information obtained is small, making it difficult to judge the posture of the workpiece. I couldn't.

That is, when the conventional optical cutting method is used for a scanning sensor for automatic welding and the weld line is searched by this method, the obtained cutting image (α) is as shown in Fig. 1. The only information that can be obtained is the position in the direction (V) perpendicular to the welding line direction (H) and the distance in the direction of approach and separation. Therefore, the inclination of the weld line in the horizontal plane, the inclination with respect to the horizontal plane, etc. cannot be determined.

In view of the above circumstances, the present invention provides a method for measuring the posture of a workpiece, particularly a workpiece having grooves of various shapes, by optical cutting. This method is characterized in that the workpiece is exposed to the peeled beam and the posture of the workpiece is measured based on the mutual relationship between the cut images obtained with both beams.

The present invention will be described in detail below with reference to the drawings.

First, the outline will be explained with reference to FIGS. 2 and 6.

FIG. 2 shows an example of a sensor for implementing the present invention, in which (1) is a sensor body, (2) is a workpiece, and (3) is a groove.

The sensor has two slit light sources (not shown),
The slit light (4a) (4h) from the light source is irradiated onto the workpiece (2) through projection windows (5) (6) provided in the sensor body (1), and the slit light (4a)
)(4/I) are each inclined at a required angle with respect to the vertical plane so that they intersect below the sensor.

In addition, a lens (7) is provided on the lower surface of the sensor body (1), at a position intermediate between the projection windows (5) and (6), so that the cut image (8 (Z)
(sh) so that it can be imaged on the image sensor (9). Note that the lens (7) and the image sensor (9) may be a normal television camera.

In the figure, H indicates the welding line direction, ■ indicates the direction perpendicular to the welding line, and Z indicates the vertical direction.

Cut image (8a) (8!+) obtained by the above sensor
is as shown in FIG. 5, for example, and the cut image of these 2 (8
α),! = Work (
2) is used to measure posture.

That is, from the cut images (8a) and (8h), the distance Dw between the sensor body (1) and the workpiece (2), the sensor body (1)
Angle Φ5 between the center line in the H direction and the welding line (longitudinal direction of the groove groove (3)), center of the sensor body (1) (displacement tri between the measurement center and the center of the workpiece, and angle between the vertical line (Z) and the welding line) Tilt F5
, the inclination α of the workpiece in the direction perpendicular to the vertical line (Z) and the welding line can be measured, and the six-dimensional posture of the workpiece (2) can be measured.

The cut image (8a) (ah) will be described in detail below.

In the figure, (3) is the bevel groove, (10) is the lens (7),
Imaging device incorporating image sensor (9), (11a) (11
A) is a slit light source with a slit light source (4a) (
4b) are tilted by θ in opposite directions with respect to the vertical plane.

Also, Fig. 5 is a cut image (8θ) captured by the imaging device 00).
Indicates the positional relationship between (8/') and the screen, ■1c.; Coordinates of medium heat in the direction of the welding line on the screen 731 Coordinates RAV at the center of the screen in the direction perpendicular to the welding line; Bending point of the cut image (8a) V of
Directional coordinates RAll + H-direction coordinates of the bending point of the cut image (8σ) RI3V; V-direction coordinates of the bending point of the cut image (8h) "+3H' H-direction coordinates of the bending point of the cut image (8b) V7 .; Coordinate V. Any above coordinate V, n; Coordinate V
Arbitrary coordinate 71A below C; Distance from coordinate H6 at coordinate V to cut image (8a)
a) Distance to Le13; Coordinates V11. A cut image (8
Distance mB to b); cut image (8) from coordinate H6 at coordinate ■7n
k) Distance dwA; Distance ctWB+ from coordinate H3 to bending point RAH
The distance from the coordinate H6 to the bending point REH is p, and the relationship in the Z direction is Od, as shown in FIG. 6; from the reference level O to the slit light (4α).

Distance to the point where (4b) intersects DW; Distance of the work salt from level 0, D,'; Distance of the work salt from 0,1, D, is p when Dw<O,z, / indicates when Dw>Od.

Next, calculations of Φ, tri, etc. will be sequentially explained.

(1) First, regarding Φ, Fig. 7 shows the state of cutaway image (4c) (4A) when Od>Dw, and Fig. 8 shows the state when Od<Dw.
In either case, it can be easily determined from the coordinates of the bending points RA and RB. That is, it is determined by, and furthermore, (RAV
-RBV), (RAHRBH), and the positive/negative determination of O5, and the positive/negative value of O5 and Dw are determined.

(ii) Regarding ld, lrl is as shown in Figure 9, l d= (■o'fl AV (OγRBv)')・
M is obtained, and in order to reduce the error, take the average of ld obtained from RAV and R13V. Here M is the optical magnification.

(iii) Regarding W, in Fig. 10, the workpiece (2) is drawn horizontally, and the sensor body is tilted. Also, in the figure (one is the top surface of the workpiece (2), α1 is the groove bottom position, and d).

D indicates the distance from the intersection of the slit beams (4α) (41!l) to the groove bottom position (13, workpiece top surface α), dA, d, A' and d, B, d, B' indicates the length of the hypotenuse of the right triangle obtained by construction.

From Figure 10 aA7=d, Acos>V/.

7L B ”” (L B CO8F3dA= cl,
(tarb V', + tan (even to 籏)) dB
= cl, (tan (θ7+W, ) −tan
quality) 'WA = clA' cos F.

cl, wB == cl, BHCOS W3d, A'=
D, (tarb '11.-1-tan (θi'
sNd, B'-D s (tan, (O70F, )
~tan, W, ) is obtained, and tonashi, ? 'LA' WA, n, B ' The positive and negative of W and 9 are determined by the positive and negative of WB.

Furthermore, if the same processing is performed for mA and nLB shown in Fig. 5, the measurement accuracy will be improved.
In Fig. 11 (a) (!') (C), the slit light (4α) (4/)) and the groove groove (3) old inclination angle α, the groove groove (3). Let θ be the half angle of the groove angle, and θα, θα
' is the inclination angle of the Surin l-image in the image with respect to the V direction, 7LB.

II+, B is the slit light (8
b) shows the distance from the coordinate H6 at a point equidistant inward from the V′ force in the cut image (8h) from the bending point of the JJ cross-sectional image (8b).

Here, it is assumed that O7 face/O2,7.

Figure 11 ((1,) (/+) Horn 1.1 from (C)
"WA--d, 1t (tTL even (-double--M]) 7 no 1.2 d, wΔ--(t21 (171θi (
=R'h)d 1-":ly,, / (to, rL(
θ to α)) i12== V, , / (tan (IJ
K+α)) to 4+-(V7μ(7jlθi)/'(t
arL (one α to θ)) M2' ” (V+l, 1a
7L θ, )/(1a−(O1(+α))■n tan (one α to θ) = −−tanθ.

1 - V.

"α-view (MFT, tashimado θ7 - ■, 9 α") tan, '(O2' ta, shima) - θ according to O3 α-(tan-1 (M2' is blank) - t6 ru 1 (n) ,t
The inclination angle α is calculated as a + tiger)/2.

As described above, the present invention can also determine the posture of the workpiece.

In the above example, the workpiece was irradiated with slit-shaped light beams tilted symmetrically, but as shown in FIG. It is also possible to irradiate at an angle (the shape of the workpiece is a V-groove), or
The relationship between the two slit-shaped rays is the first when irradiating a plane.
Even if they are parallel as shown in Figure 3 (a), Figure 16 (h)
It may also be tilted as shown in . In particular, Figure 16 (b
), it is possible to measure without rotating the groove so that the light beam is perpendicular to the longitudinal direction of the groove.

Next, another embodiment of the present invention will be described.

In the present invention, two slit-shaped light beams are used to determine the shape and posture of the workpiece based on the mutual relationship between the two light beams.However, if both light beams are imaged simultaneously and the image processing is performed, the shape analysis of the cut image is possible. It becomes complicated. Therefore, in the method described below, both light beams are alternately irradiated in a continuous manner so that the image is always a sectioned image by one light beam.

However, if you treat the screen until the light beam switches as one screen, perform shape analysis, etc. every screen, store that information, and compare it with the shape analysis results of the next screen, the calculations required for shape analysis, etc. The capacity can be significantly reduced compared to the case where images cut by two light beams are displayed on the same screen.

Further, FIGS. 14 to 16 explain still other embodiments.

In this embodiment, a television camera is used as the imaging device.

In the figure, 0Φ indicates a television camera, and (11a) and (11b) indicate a slit light source.

Slit light source (4a') imaged by TV camera A4
The cut image in (4b) is converted to an analog signal by an A/D converter (
The data is sent to the storage device 0Q, digitized, and sent to the storage device 0Q for storage. The signals stored in the storage device αO are processed by the microcomputer αO to determine the shape.

The slit light sources (11a) (11h) are connected to the driver (18a).
) (18b) to emit light intermittently. This light emission timing is controlled by a timing generation circuit α9). In addition, the image from the TV camera 0→ is made up of a large number of scanning lines, and the scanning lines are activated every other time and scan the screen twice (one round as a scanning line) to complete the image. . Therefore,
By changing the slit light irradiated in the first and second scans, different images can be obtained in the first and second scans, and the cut images of the two slit lights can be displayed simultaneously on the screen. is never displayed. The wire is a synchronization circuit that switches Surin I and light (combined to synchronize the first and second scans).

Also, even if the scanning line does not start in the row of seedlings but starts continuously, the position of the assessment line and the address of the storage device α→ are made to correspond,
Moreover, by switching the slit light for each scan, it is possible to display cut images of two slit lights on one screen and easily separate and process the two images in the same manner as described above.

For example, as shown in Figure 15, cut images (8α) (8
b) will be displayed. The timing of driving the slit light source (Ila) (1L6) at this time is as shown in Figure 16. This point is one point on the cut image in one scanning line.

In this embodiment, the signal processing can be completed while the scanning line makes one round, so the signal processing speed can be greatly improved.

As described above, according to the present invention, it becomes possible to measure the posture of a workpiece, which could not be measured using the conventional optical cutting method.1.

[Brief explanation of drawings]

Fig. 1 is a diagram showing a cut image obtained by a conventional optical cutting method, Fig. 2 is a schematic diagram of an apparatus for carrying out the present invention, Fig. 3 is an explanatory diagram of a cut image obtained with the same apparatus, and Fig. 4 is a diagram showing the relationship between the device and the workpiece, FIG. 5 is an explanatory diagram of the position of the cut image on the screen, FIG. 6 is a diagram showing the relationship between the slit light and the workpiece, FIGS. 7 and 8, Figure 9 is a diagram showing the positional relationship between the two cut images on the screen, Figure 10 is a diagram showing the relationship of the slit light to the workpiece, and Figures 11 (a), (b), and (c) are diagrams showing the relationship of the slit light to the workpiece. Explanatory diagram showing the relationship and cut image, FIG. 12(a) (151, FIG. 16(C1(/
+1 is an explanatory diagram showing the relationship between the two slit lights, FIG. 14 is a block diagram showing another embodiment, FIG. 15 is an image diagram in the same embodiment, and FIG. 16 is an illustration in the same embodiment. A timing chart is shown below. (4c) (4b) is a slit light, (8(Z)(8/)
) is a cut image, C0) is an image sensor, (11a) (11h)
indicates a slit light source. Figure 7 Figure 8 Figure 10 Figure 11 (b) (a) Figure 12 (a) (b) Figure 13 (a) (b)

Claims (1)

[Claims] 1) By optical cutting, which is characterized in that the two slit-shaped light beams are irradiated onto the workpiece at an angle with respect to each other, and the posture of the workpiece is measured based on the mutual relationship between the cut images obtained by both light beams. Posture measurement method. 2) The posture measuring method by light cutting according to claim 1, wherein the two slit-shaped light beams are alternately irradiated onto the workpiece.