JPH04203909A - Position alignment apparatus - Google Patents

Abstract

PURPOSE:To execute position alignment of a moving body with an object highly precisely in a short time without being affected by instruction precision, by determining the relationship in relative positions on the basis of positional information obtained by recognizing a shadow from the object and two shadows formed by two light sources. CONSTITUTION:An image processing element 13 in a controller 5 recognizes first the position of a shadow formed by a hole 8 from a pattern of a laser light sensed by a camera 3, according to an instruction from a central control element 11. Next, the position of a shadow 9 of the fore end of a component 6 which is formed on a workpiece 7 by a light projected from a light source 2a and intercepted by the component 6 and the position of a shadow 10 of the fore end of the component 6 which is formed on the workpiece 7 by a light projected from a light source 2b and intercepted by the component 6 are recognized by template matching. Recognized position data thus determined are sent to the control element 11 and the relationship in relative positions of the position of the hole 8 and the position of the fore end of the component 6 is determined three-dimensionally from those positions of the fore end of the component 6 and the pattern of the hole 8. According to this constitution, position alignment of a moving body with an object can be executed highly precisely in a short time irrespective of instruction precision.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a device that aligns an object being moved by a moving mechanism to a predetermined position on a target object, such as a screw tightening robot with a visual function, a component insertion machine, and a component mounting device. The present invention relates to an alignment device that can be used for machines, etc.

Conventional technology Conventionally, when aligning a moving object and a target object using a robot with vision, the reference positions of the target object, the moving object, and the robot operating position as a moving mechanism are taught, and the position of the target object is determined by a camera. Recognize the position of the moving object from the input image, recognize the position of the moving object from the image input with another camera, and calculate the difference between the recognition position when the target object is at the reference position and the recognition when the moving object is at the reference position. The method used was to convert each visual coordinate into robot coordinates based on the difference in position and determine the amount of motion correction from the taught reference position of the moving mechanism.

Problems to be Solved by the Invention When positioning is performed with the above-described configuration, the robot operation and the teaching settings of the reference positions of the target object and moving object directly affect the accuracy of the positioning work.

Therefore, when highly accurate positioning is required, teaching often requires a great deal of effort. Further, the accuracy of positioning work cannot exceed the accuracy of teaching settings. In addition, recognition is performed in two steps, and in many cases recognition is performed in a separate step from the alignment operation, which tends to increase the time required to perform the work operation including the recognition operation. There was a problem.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide an alignment device that can align a moving object and a target object with high precision in a short time without being affected by teaching accuracy.

Means for Solving the Problems In order to solve the above-mentioned problems, the positioning device of the present invention is a positioning device for positioning a moving object, which is moved by a moving mechanism, at a predetermined position of a target object. Two light sources that project light onto a moving object and the target object from two different directions that are not parallel to the perpendicular to the target object, and the reflected light of the light projection pattern on the target object at an angle different from the direction in which the light sources project the light. A camera that receives light, an image processing means that determines the relative positional relationship between the moving object and the target object from the input image received by the camera, and a control that determines the direction and amount of movement of the moving object from the relative positional relationship and controls the movement of the moving mechanism. and the image processing means recognizes the shadow generated from the shape of the target object and the two shadows generated when the light projected from the two light sources is blocked by the moving object. The present invention is characterized in that it is configured to determine the relative positional relationship between a moving object and a target object based on positional information.

According to the above configuration of the present invention, the relative positional relationship between the moving object and the target object can be determined from one camera input image processing, and the moving direction and moving amount of the moving mechanism can be determined from the relative positional relationship. Therefore, positioning can be achieved with high accuracy commensurate with recognition accuracy, regardless of teaching.

Embodiment Hereinafter, a positioning device according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a positioning device for positioning the tip of a component 6 as a moving object with a 68 of a workpiece 7 as a target object. In FIG. 1, a robot 1 serving as a moving mechanism moves a gripping device 4 at its tip forward and backward, left and right, and up and down by a ball screw driven by an electric motor. The gripping device 4 grips the component 6. Further, the first and second light sources 2a and 2b and the camera 3 are attached to the gripping device 4 so as to face each other or orthogonally to each other, and move together with the gripping device 4 by the operation of the robot 1.

The light emitted by the first and second light sources 2a and 2b is laser light that travels in a straight line, and projects a rectangular surface pattern. The lens of the camera 3 is equipped with a filter that transmits the wavelength band of the laser beam, so that the pattern of the projected light and the shape of the shadow are received. The control signal lines of the robot 1, the first and second light sources 2a and 2b, and the camera 3 are connected to a controller 5, respectively, and are controlled by input and output of the controller 5.

FIG. 2 is a block diagram showing the configuration of the controller 5, which includes a central control section 11, a moving mechanism control section 1, and a moving mechanism control section 1.
2, consists of an image processing unit 13, each of which has a built-in microcomputer, memory, and 110, and a system
Communication is carried out via 4. The central control section 11 sends operation commands to the moving mechanism control section 12 and image processing commands to the image processing section 13 according to a program stored in the memory.

The movement mechanism control section 12 controls the electric motor of the robot 1 according to instructions from the central control section 11 .

In accordance with the command from the central control unit 11, the image processing unit 13 determines the position of the shadow by 68 based on the pattern of the laser light received by the camera 3, and the workpiece 7 where the light emitted from the light source 2a is blocked by the component 6. Shadow 9 of the tip of part 6 generated above
(see Fig. 4) and the position of the shadow 10 (see Fig. 5 or 6) at the tip of the part 6 that is generated on the workpiece 7 when the light emitted from the light source 2b is blocked by the part 6. The position is recognized by template matching, and the obtained recognized position data is sent to the central control unit 11. The templates used in the recognition process are shown in Figures 3(a), (b), (C), and (d).
) is stored in advance in the memory of the image processing section 13.

Next, before explaining the control operation of the central control unit 11, please refer to FIG. 1, FIG. 5, and FIG. and explain.

The light emitted from the light source 2a partially hits the tip of the part 6 and creates a pattern around the 68 of the workpiece 7. Input this using camera 3. As shown in FIG.
and a shadow 9 at the tip of the component 4. Further, similar patterns with different directions including the shadow 10 at the tip of the component 6 are generated by light projected by the light source 2b from different angles. When these images are input using camera 3, Fig. 5 fc
) and patterns such as those shown in FIG. 6(C) are obtained. FIG. 5 is an explanatory diagram of an image pattern when the light sources 2a and 2b are disposed facing each other, and FIG. 6 is an explanatory diagram of an image pattern when the light sources 2a and 2b are disposed orthogonally.

Depending on the angle that the light projection directions of the two light sources 2a and 2b make with respect to the reflecting surface, the direction is perpendicular to the line segment from the internal dividing point of the line segment connecting the tip position of the shade 9 and the tip of the shade 10. The tip of the component 6 exists above a position at a distance proportional to the length of the line segment in the direction. Further, the height of the tip of the component 6 from the workpiece 7 can be determined as a size proportional to the length of the line segment. From the position of the tip of these parts 6 and the position of the hole 8 pattern, it is possible to three-dimensionally determine the relative positional relationship between the position of the 68 and the position of the tip of the part 6.

When two lights '1Q2a and 2b and the camera 3 are arranged so that the projection directions of the two light sources 2a and 2b are opposite on the plane projected onto the reflective surface of the target object, the part 6 The calculation for determining the relative position of the tip of the hole 8 with respect to the position of the hole 8 is as follows.

The displacement of the tip of the component 6 with respect to the hole 8 in the image coordinate system is (dx, dy, dz), and the coordinates of the center of the shape pattern of the hole 8, the shadow 9 of the component tip, and the shadow 10 of the component tip in the image coordinate system are respectively (x8.y8), (χ9.y9), (x 1
0. y 10), dx= (x9+xlo
)/2-x8 d y= (y 9+ylO) /2-y 8d z-
(x9-xlo) /2 However, this calculation is valid only when the angle between the light emitting direction of light source 2 and the reflective surface and the angle between the light receiving direction of camera 3 and the reflective surface are each exactly 45 degrees. .

In addition, if the light sources 2a and 2b and the camera 3 are arranged so that the light projection directions of the two light sources 2a and 2b are exactly orthogonal to each other on the plane projected onto the reflective surface of the workpiece 7, which is the target object, the tip position of the component 6 The calculation to find the relative position to the position of 68 is as follows.

dχ=χ9-x8 dy=ylOy8 dz= ((x9-xlO) +(y9 ylo)
)/2 However, this calculation is valid only when the angle between the light emitting direction of the light sources 2a and 2b and the reflecting surface and the angle between the light receiving direction of the camera 3 and the reflecting surface are each exactly 45 degrees.

Next, the control operation of the central control section 11 for determining the relative positional relationship between the tip of the component 6 and the 68 of the workpiece 7 will be explained with reference to FIG.

The central control unit 11 sends a recognition command to the image processing unit 3,
Position of shape pattern from image processing unit 13 to 68, part 6
Shadow of the tip of 9. Receiving the screen coordinate value of the position of 10, find the relative positional relationship between the tip of component 6 and 68, and based on this, move the tip of component 6 to the position of hole 8. The motion amount of the robot 1 is calculated and a motion command is sent to the moving mechanism control section 12.

The relative positional relationship between the tip of the component 6 as a moving object and the hole 8 of the workpiece 7 as a target object is as follows: when the two light sources 2a and 2b are arranged facing each other, and when the two light sources 2a and 2b are arranged orthogonally, Each is calculated according to the procedure explained above, and (d x.

dy, dz) is determined as a relative position in the image coordinate system, and this is further converted from the image coordinate system to the coordinate system of the robot 1 as a moving mechanism by the following calculation, and the movement of the robot for alignment is determined. Vector (rx, ry, rz
) is required.

(rx, ry, rz) = (dx, dy, dz)T where T is a (3X3) coordinate transformation matrix.

In this embodiment, if the component 6 as a moving object is a screw held by a screw driver, and the target object 68 of the workpiece 7 is a screw hole, the positioning device of the present invention can be applied to a screw tightening robot. can do.

In addition, in this embodiment, the part 6 held by the robot 1
If 68 of the workpiece 7 as a target object is an insertion hole, the part insertion robot 2 can be applied.

Furthermore, in this embodiment, if the component 6 is used as a mounting component and the workpiece 7 is used as a mounting target board, the present invention can be applied to a component mounting robot.

Furthermore, if the moving object is a probe and a predetermined position of the target object is a terminal, the present invention can be used as an inspection device that positions the probe and the terminal.

Effects of the Invention As described above, according to the positioning device of the present invention, the moving object and the light source are aligned so that the target object and the moving object are within the range where the camera captures the reflected light of the light projected from the light source. By simply setting the teaching setting for the camera to move, the moving object and the target object can be aligned with the position detection accuracy and the positioning accuracy of the moving mechanism, regardless of the teaching accuracy, without requiring precise arrangement adjustment of the light source or camera. It can be carried out.

Therefore, it is no longer necessary to teach the operating position of the moving mechanism with positioning accuracy, and the labor required for teaching is greatly reduced.

In addition, since visual perception can determine the positions of the moving object and the target object simultaneously from the same human-powered image, it is possible to achieve effects such as visual feedback processing for the operation of the moving mechanism can be performed in a short time.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing a schematic configuration of a positioning device according to an embodiment of the present invention, Fig. 2 is a perspective view showing the configuration of a controller, and Figs. Figures 4(a) and 4(b) show the templates used.
Figures 5 (a), (b), and (C) are explanatory diagrams of the state of light projection onto the target object from the light source and the patterns generated. Fig. 6 is an explanatory diagram of a pattern caused by only the first light source, a light projection state of the second light source, and a pattern in the light projection state of the first and second light sources in the case of the present invention. ) is a pattern created only by the second light source when the second light source is arranged perpendicular to the first light source, the light projection state of the second light source, and the pattern in the light projection a′ state by the first and second light sources. FIG. 7 is a flowchart of the control device for positioning operation. 1--・--・--・・-------1 robot (moving mechanism) 2a-m--11 first light source 2b--Second light source 3- -------One camera 5, -,,,,,,,,,,,,, -Controller 6--One part (moving object) 7--------Work (Target object) 8---1.
−−・−・−Hole (predetermined position of target object) 9−1−～−
-11--Shade 10 at the tip of one component----Shade 11 at the tip of one component--11---Central control section 12--Moving mechanism control section 13--・−
---Image processing section.

Claims (1)

[Claims] (1) A positioning device that aligns a moving object that is moved by a moving mechanism to a predetermined position on the target object, the device aligning the moving object and the target object from two different directions that are not parallel to the perpendicular line drawn from the moving object to the target object. Two light sources that emit light, a camera that receives the reflected light of the light projection pattern on the target object at an angle different from the direction in which the light sources emit light, and the relative positional relationship between the moving object and the target object based on the input image received by the camera. and a control means for determining the moving direction and amount of movement of the moving object from the relative positional relationship and controlling the movement of the moving mechanism. The system is configured to determine the relative positional relationship between the moving object and the target object based on positional information obtained by recognizing two shadows generated when the light projected from the two light sources is blocked by the moving object. A positioning device characterized by: