JPH0130592B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic profile control device applied to a welding machine, etc., and an object of the present invention is to simplify the configuration.

Conventionally, automatic profiling control devices that automatically derive the profiling position relative to the weld line of the workpiece are attached to a movable body that can move vertically and back and forth, and project a fan-shaped light beam that intersects the weld line of the workpiece. a television camera attached to the moving body to image the vicinity of the luminous flux; a television receiver for a monitor that displays an image of the vicinity of the luminous flux produced by the camera on a screen; and a television receiver for processing the image on the screen. and an image processing means for deriving a profile position with respect to the weld line, and the image processing means calculates a deviation between a point on the image corresponding to a point on the weld line and a reference point on the screen. A deviation between a reference point on the moving surface of the movable body and a point on the weld line is calculated, and these operations are repeated to derive a profile position with respect to the weld line.

However, with this type of automatic tracing control device,
Normally, images taken from directly above the welding line are processed, so the deviation obtained by image processing is only the deviation in the front-back direction. Since it is not possible to derive the amount of movement in the direction, other sensors such as an arc sensor are provided in addition to the light source, camera, receiver, and image processing means, and the sensor is used to determine the reference point of the moving surface of the moving object. Although the deviation in the vertical direction from the welding line is derived and the amount of movement of the moving body in the vertical direction is derived, since the sensor is newly required,
The disadvantage is that the configuration is complicated.

In addition, in order to image the welding line from directly above, the light source and camera must be fixed, making it impossible to image the welding line from a free angle depending on the shape of the workpiece. If the line is imaged diagonally, there is a problem in that the amount of movement of the moving body in the vertical and longitudinal directions cannot be derived.

This invention has been made with the above-mentioned points in mind, and includes a first slide body provided on a mounting body so as to be movable in the vertical direction, and a first slide body provided on the first slide body so as to be movable in the front-back direction. a second slide body;
A vertical support body is attached to the second slide body, and a fan-shaped support body is attached to the lower end of the support body so as to be rotatable with the left and right direction as a rotation axis, and crosses the weld line in the left and right direction of the workpiece from an angle. a light source that projects a luminous flux; and a light source that is rotatably attached to the lower end of the support body integrally with the light source, the imaging direction being inclined with respect to the support body, and imaging the vicinity of the luminous flux from a direction perpendicular to the welding line. an imaging means; a rotary encoder provided on the rotation axis to detect the angle of the imaging direction of the imaging means with respect to the front-rear direction; a display means for displaying an image near the light beam by the imaging means on a screen; and the screen. an image processing means for processing the above image to derive the coordinates of a point on the welding line in a set coordinate system on the screen; a coordinate conversion means for converting coordinates into coordinates in a rotated conversion coordinate system to derive a profile position with respect to the welding line and deriving a movement amount of both slide bodies, and a servo that moves both slide bodies by the derived movement amounts respectively. The present invention provides an automatic tracing control device equipped with a control section.

Therefore, according to the automatic tracing control device of the present invention, image processing means is provided for processing the displayed image on the screen of the display means to derive the coordinates of each point of the welding line on the screen, and By providing a coordinate conversion means for converting coordinates into coordinates rotated by an angle detected by a rotary encoder, there is no need to provide other sensors as in the conventional case, and the coordinates on the screen can be converted to coordinates on the moving surface of both slide bodies. Since the coordinates can be converted into the coordinates of the coordinate system in

Furthermore, the imaging direction of the imaging means can be freely selected according to the shape of the workpiece, and no matter which imaging direction is selected, the amount of movement of both slide bodies can be accurately derived. .

Next, the present invention will be described in detail with reference to drawings showing one embodiment thereof.

First, in FIGS. 1 and 2 showing the external appearance of the device, 1 is a mounting body, 2 is a first slide body consisting of a servo motor, and is attached to the front end of the mounting body 1 so as to be movable in the vertical direction; 3 is a mounting body; A second slide body consisting of a servo motor is attached to the lower end of the first slide body 2 so as to be movable in the front and back direction, and 4 is a vertical support whose upper end is attached to the front end of the second slide body 3. The slide bodies 2, 3 and the support body 4 constitute a movable body 5 that is movable in the vertical and front-back directions, and a welding torch is attached to the movable body 5, although not shown.

Reference numeral 6 denotes a light source which is attached to the lower end of the support 4 so as to be rotatable with the left-right direction as the axis of rotation, and projects a fan-shaped beam of light diagonally across the welding line 8 in the left-right direction of the workpiece 7 having a V-shaped groove. A certain laser, 9, is a television camera that is an imaging means, and is rotatably attached to the lower end of the support 4 together with the laser 6, and the imaging direction is inclined with respect to the vertical direction, and the vicinity of the light beam is directed to the welding line. 8, and outputs an imaging signal to a monitor television receiver serving as a display means, and the imaging signal causes an image near the light beam to be displayed on the screen of the receiver. , the light source 6, the camera 9, and the image receiver constitute a light cutting sensor 10.
Note that 11 is a rotary encoder that detects the angle θ of the imaging direction of the camera 9 with respect to the front-rear direction.

Next, FIG. 3 showing the control circuit will be explained.

In the figure, 12 is an image processing means, which has a set coordinate system (hereinafter referred to as Y-Z coordinate system) in which the horizontal and vertical median lines of the screen of the receiver are the Y-axis and Z-axis, respectively. The coordinate components of the points on the image corresponding to the points on the welding line 8 are derived.

Reference numerals 13 and 14 denote Y and Z coordinate conversion means, respectively, which transform the coordinate components in the Y-Z coordinate system on the screen into the moving surface of the moving body 5 by rotating the Y-Z coordinate system by the rotation angle θ of the camera 9. The above transformation coordinate system, that is, the coordinate system on the surface with the vertical and front-back directions as the Ys axis and Zs axis, respectively (hereinafter referred to as the Ys-Zs coordinate system)
Convert to the coordinate components of both slide bodies 2 and 3
The amount of movement is derived and a converted signal is output for each.

15 is an attitude detection circuit that detects the attitude of the sensor 10, detects the rotation angle of the camera 9 together with the rotary encoder 11, and outputs an angle detection signal to both conversion means 13 and 14, and 16 and 17 respectively convert the two conversion signals. - Amplifier that multiplies the output by K, 18,
Reference numeral 19 denotes an addition/subtraction unit that adds both the above-mentioned converted signals from the amplifiers 16 and 17 and a signal from a rotary encoder for a servo motor, which will be described later.
0 and 21 are servo amplifiers that amplify the signals from the adder/subtractors 18 and 19, respectively; 22 and 23 are servo motors for both slide bodies 2 and 3 driven by signals from the servo amplifiers 20 and 21, respectively;
Numerals 24 and 25 are tachometer generators, and 26 and 27 are rotary encoders for servo motors, which detect the amount of rotation of the servo motors 22 and 23, respectively, and output a rotation amount detection signal for feedback to the addition/subtraction section. Parts 18, 19,
Servo amplifiers 20, 21, servo motor 22,
23 and rotary encoders 24 and 25 constitute a servo control section 28, and the circuit shown in FIG. 3 constitutes a control circuit.

Now, when the workpiece 7 having a V-shaped groove is imaged by the camera 9 from the direction of the arrow in FIG. 4a,
An image as shown in Figure b will be displayed on the screen S of the receiver, and on the screen S, the part of the light beam from the laser 6, that is, the shaded area in Figure b, will be bright, and the rest will be dark. An image is displayed, and the image processing means 12 derives the coordinates of the welding line 8 of the workpiece 7 on the screen S based on the image.

That is, to explain the principle of image processing, when the object to be welded 7 having a V-shaped groove is imaged by the camera 9 from the direction of the arrow in FIG. 4a, an image as shown in FIG. Displayed on the screen S, the equations in the Y-Z coordinate system of the center lines A and B of the bright strips P ₁ and P ₂ of the image are respectively expressed as Z=-CY+D...Z=EY+F... If the coordinates of each point on the center lines A and B are (yi, zi) and the number of data are Na and Nb, respectively, then each coefficient C, D, E, F in the above equation can be calculated based on the method of least squares. C=-Na・Σyi・zi+Σyi・Σzi／Na・Σyi ² −(Σy
i) ² ...D=Σyi ²・Σzi−Σyi・Σyi・zi／Na・Σyi ² −(Σ
yi) ² … E=Nb・Σyi・zi+Σyi・Σzi／Nb・Σyi ² −(Σyi
) ² ...F=Σyi ²・Σzi−Σyi・Σyi・zi/Nb・Σyi ² −(Σ
yi) ² ... Therefore, the coordinate components of the coordinates (Δy, Δz) of the point on the screen S corresponding to the point on the welding line 8, that is, the intersection point Q of both lines A and B, are respectively Δy=F−D /C+E...Δz=E・D+C・F/C+E... Note _that even if _the welded workpiece 7' has a groove as shown in FIG. (Δy', Δz') is expressed in the same way as above.

Therefore, the image processing means 12 calculates the above-mentioned formulas, derives the coordinates of Q on the screen S corresponding to the points on the welding line 8, and repeats these operations to calculate Y-Z. The coordinates of each point of the welding line 8 in the coordinate system are derived.

However, the point Q derived as described above
Even if the servo motors 22 and 23 are driven based on the coordinates in the Y-Z coordinate system, that is, the deviation from the origin O, which is the reference of the Y-Z coordinate system, the camera 9
is tilted by an angle θ as shown in FIG.
The torch attached to the welding line 8 will not be controlled in the tracing position relative to the welding line 8.

Therefore, it is necessary to convert the deviation on the screen S into a deviation on the moving surface of the moving object 5, and both conversion means 13 and 14 perform the conversion.

That is, as in the case of FIG. 4, when the image of the workpiece 7 having a V-shaped groove is displayed as shown in FIG. After the coordinates (Δy, Δz) of point Q in the Y-Z coordinate system are derived, the Y coordinate component Δy and Z coordinate component Δz of point Q are calculated as Δys=Δy・cosθ+Δz・sinθ...Δzs=Δz·cosθ−Δy·simθ… Based on the formula, both conversion circuits 13 and 14 convert the moving surface of the moving body 5 into coordinate components Δys and Δzs in the Ys-Zs coordinate system, respectively. Note that θ is the rotation angle of the camera 9 based on the angle detection signal from the attitude detection circuit 15.

At this time, the relationship between the Y-Z coordinate system and the Ys-Zs coordinate system is as shown in FIG. 6b, where the Y-Z coordinate system is rotated by the same angle as the rotation angle θ of the camera 9. -Zs coordinate system, the above equation is derived from the relationship shown in figure b, and coordinate transformation is performed.

Then, the servo motors 22 and 23 are driven and moved based on the coordinate components Δys and Δzs obtained by conversion by both the conversion means 13 and 14, that is, the deviation from the origin O which is the reference point of the Ys-Zs coordinate system. body 5
Both slide bodies 2 and 3 have the coordinate components Δys, Δzs
The torch is moved in the Ys-axis and Zs-axis directions by an amount based on the welding line 8, and the torch is controlled to a predetermined tracing position with respect to a certain point on the welding line 8. These operations are repeated so that the torch is always at the tracing position with respect to the welding line 8. Welding is performed under the control of

Therefore, according to the embodiment, it is possible to simultaneously and automatically derive the amount of movement of both slide bodies 2 and 3 of the movable body 5 in the vertical and longitudinal directions based on the image obtained by the optical cutting sensor 10. There is no need to provide other sensors such as an arc sensor as in the conventional case, and the configuration can be simplified.

In addition, since the camera 9 is rotatably attached to the support 4, the imaging direction of the camera 9 can be freely selected, and at the same time, regardless of which imaging direction of the camera 9 is selected, both slides of the moving body 5 The amount of movement of the bodies 2 and 3 can be accurately derived, and the welding torch can always be controlled to an accurate tracing position.

[Brief explanation of drawings]

The drawings show one embodiment of the automatic tracing control device of the present invention, in which Fig. 1 is a right side view, Fig. 2 is a partial plan view, Fig. 3 is a block diagram of the control circuit, and Figs. Figure 6 is an explanatory diagram of the operation, Figures 4a and 5a are cross-sectional views of the workpieces having different grooves, and each figure b is an image of the vicinity of the welding line of the workpiece in each figure a. Figure 6a shows an image near the welding line of the workpiece in Figure 1, and Figure 6b shows the relationship between the Y-Z coordinate system and the Ys-Zs coordinate system during coordinate transformation. FIG. 1... Mounting body, 2, 3... First and second slide bodies,
4... Support body, 6... Laser, 7... Welding object, 8... Welding line, 9... Camera, 11... Rotary encoder,
12... Image processing means, 13, 14... Coordinate conversion means, servo control section.

Claims (1)

[Scope of Claims] 1. A first slide body provided on the mounting body so as to be movable in the vertical direction; a second slide body provided on the first slide body so as to be movable in the front-rear direction; and the second slide. a support member attached to the body in the vertical direction; and a support member attached to the lower end of the support member so as to be rotatable with the left and right directions as a rotation axis, and projects a fan-shaped light beam obliquely across the welding line in the left and right direction of the workpiece. a light source; an imaging means that is rotatably attached to the lower end of the support body integrally with the light source, has an imaging direction inclined with respect to the support body, and captures an image of the vicinity of the light beam from a direction perpendicular to the weld line; a rotary encoder provided on the rotating shaft and detecting the angle of the imaging direction of the imaging means with respect to the front-rear direction; a display means for displaying an image near the light beam by the imaging means on a screen; and a display means for displaying the image on the screen. an image processing means for processing and deriving coordinates of a point on the welding line in a set coordinate system on the screen; and converting the derived coordinates into converted coordinates obtained by rotating the set coordinate system by an angle detected by the rotary encoder. a coordinate converter that converts the coordinates into coordinates in a system to derive a tracing position with respect to the welding line and derives the amount of movement of both slide bodies; and a servo control unit that moves each of the slide bodies by the derived movement amount. An automatic tracing control device characterized by: