JPH04201021A - Positioning device - Google Patents

Abstract

PURPOSE:To carry out positioning at high accuracy by recognizing a shade generated out of the shape of an objective, a shade generated out of a projected light that is cut by a moving material, and a shade generated out of the reflected light from the objective, which is cut by the moving material. CONSTITUTION:When a light source 2 and a camera 3 are opposed with each other, and are thus arranged, the light projected from the light source 2 is irradiated on a part of parts 6, and forms a pattern comprising a part formed by a hole 8 of a work 7, and a shade 9 of the point of the parts 6. When an image is input by the camera 3 at a different angle, the reflected light from the work 7 is cut by the point of the part of parts 6, and a shade 10 of the reflected light of the point of the parts 6 exists in the pattern in an input image. The shades 9, 10 are recognized by a template that is preliminarily stored, and the existence of the point of the parts 6 is determined from the internal division point of a line between each point of the shades 9, 10, to the upper part of the position of the distance proportional to the length of the line, perpendicular to the line, while the height from the work 7 of the point of the parts 6 is determined in such a way that it is proportional to the length of the line. The relative position of the hole 8 and the parts 6 can thus determined in three dimension.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a device for aligning an object held 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 When a machine such as a robot performs position alignment using vision, the reference operating position and the coordinate transformation parameters between the robot's coordinate system and the visual information coordinate system are taught in advance. Based on the difference between the visual information data of the alignment target at the standard operating position and the visual information data during actual work, a transformation calculation is performed using coordinate transformation parameters to determine the amount of motion correction from the reference operating position, and Many robots are configured to operate based on this.

Problems to be Solved by the Invention In order to correct the robot operating position from visual information in this way, it is necessary to accurately know in advance the conversion parameters from visual coordinates to locomotor coordinates. However,
Due to camera mounting angles, light source mounting angles, workpiece inclination, robot installation precision, etc., it is difficult to accurately position mechanical devices according to predetermined conversion parameters, so it is necessary to accurately know the conversion parameters. The problem is that teaching requires a lot of effort. In particular, there is a problem that the workpiece that is the surface to be illuminated is different each time, causing variations, and it is difficult to accurately correct the robot operating position from visual information using predetermined conversion parameters. Ta.

SUMMARY OF THE INVENTION In view of the above 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 using simple instructions.

Means for Solving the Problems In order to solve the above 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. A light source that projects light onto a moving object and the target object in a direction that is not parallel to a perpendicular line positioned at the target object, and a camera that receives reflected light from a light projection pattern on the target object at an angle different from the direction in which the light source projects. , an image processing means for determining the relative positional relationship between the moving object and the target object from an input image received by the camera;
The image processing means determines the moving 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 controls the movement of the projected light and the shadow generated from the shape of the target object. It is characterized by being configured to recognize the shadow created by being blocked by an object and the shadow created by reflected light from the target object being blocked by a moving object to determine the relative positional relationship between the moving object and the target object. shall be.

Preferably, it is configured to determine the relative positional relationship between the moving object and the target object based on the movement direction and movement amount of the shadow recognized when the moving object is moved by a predetermined amount.

According to the present invention, the moving object and the camera/light source are moved so that the target object and the moving object are within the field of view of the visual system, that is, within the range where the camera can capture the reflected light emitted from the light source. If the teaching settings are set in this manner, the positioning of the moving object and the target object can be performed using the visual position detection accuracy and the positioning accuracy of the moving mechanism, regardless of the teaching accuracy, without requiring precise arrangement adjustment of the camera and light source. can. Furthermore, since the positions of the moving object and the target object can be determined simultaneously from the same human-powered screen, feedback processing for the operation of the moving mechanism can be performed in a short time.

In addition, by determining the relative positional relationship between the moving object and the target object based on the direction and amount of movement of the shadow recognized when the moving object is moved by a predetermined amount, the tilt of the target object becomes slightly different each time. However, the relative positional relationship can be accurately determined by the same process, and positioning can be performed accurately.

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. The light source 2 and the camera 3 are attached to the gripping device 4 so as to face each other or to be orthogonal to each other, and move together with the gripping device 4 as the robot 1 moves. The light emitted by the light source 2 is a straight laser beam,
Emits light in a square pattern. The lens of camera 3 has
A filter is attached that transmits the wavelength band of the laser beam, so that the projected pattern and the shape of the shadow are received. Control signal lines for the robot controller 1, light source 2, and camera 3 are each connected to a controller 5, and are controlled by input and output of the controller 5.

FIG. 2 is a brochure diagram showing the configuration of the controller 5, which includes a central control section 11, a moving mechanism control section I
2. Consists of an image processing unit 13, each with a built-in microcomputer, memory, and Ilo, 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 a command from the central control unit 11, the image processing unit 13 determines the pattern position of the hole 8 based on the pattern of the laser light received by the camera 3, and determines the position of the pattern of the hole 8 on the workpiece 7 because the light emitted from the light source 2 is blocked by the component 6. The shadow 9 at the tip of the part 6 generated in
4) and the shadow 10 that is generated when the light incident on the camera 3 of the projection pattern on the workpiece 7 is blocked by the component 6.
(See FIGS. 5 and 6) is recognized by template matching, and the obtained recognized position data is sent to the central control unit 11. The templates shown in FIGS. 3A, 3B, 3C, and 3D are stored in advance in the memory of the image processing section 13 as templates used in the recognition process.

Next, before explaining the control operation of the central control unit 11, refer to FIG. 1 and FIGS. 5 to 8 for a method of determining the relative positional relationship between the tip of the component 6 and the hole 8 of the workpiece 7. and explain.

The light emitted from the light source 2 partially hits the tip of the component 6,
A pattern is generated around the hole 80 of the workpiece 7. Input this using camera 3. The light emitted from the light source 2 hits the tip of some parts 6, and the pattern generated around the hole 8 of the workpiece 7 is as shown in FIGS. 5(a) and 6(a). 68 and a shadow 9 at the tip of the component 6. Furthermore, this is shown in Figures 5(b) and 6.
When images are input using the camera 3 from different angles as shown in Figure (b), some of the reflected light from the workpiece 7 is blocked by the tip of the part 6, resulting in , a shadow 10 of reflected light from the tip of the component 6 exists in the pattern in the input image. FIG. 5 is an explanatory diagram of an image pattern when the light source 2 and camera 3 are arranged facing each other, and FIG.
FIG. 3 is an explanatory diagram of an image pattern when the camera 3 and the camera 3 are arranged perpendicularly to each other.

Depending on the angle that the light projection direction of the light source 2 and the direction of the camera 3 form with respect to the reflective surface of the workpiece 7, from the internal dividing point of the line segment connecting the tip position of the shadow 9 and the tip of the shadow 10 to the line segment. The tip of the part 6 is located above a distance proportional to the length of the line segment in the vertical 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 hole 8 and the position of the tip of the part 6.

When light #2 and camera 3 are arranged so that the light emitting direction of light source 2 and the light receiving direction of camera 3 are opposite on the plane projected onto the reflective surface of workpiece 7, which is the target object, The calculation to find the relative position with respect to the position of 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 hole shape pattern, the shadow 9 of the component tip, and the shadow 10 of the component tip in the image coordinate system are respectively (x8 .y8), (x9.y9), (x 10.
y 10), dx= (x9+xlO)/
2-x8 dy-(y9+ylO) /2-y8 dz-(x9-xlO)/2 However, this calculation is valid depending on the angle formed by the light projection direction of light source 2 and the reflecting surface, and the light receiving direction and reflection of camera 3. This is a case where the angle formed by each surface is T degree 45°.

In addition, when the light source 2 and camera 3 are arranged so that the light emitting direction of the light source 20 and the light receiving direction of the camera 3 are exactly perpendicular to each other on the plane projected onto the reflective surface of the workpiece 7, which is the target object, the position of the tip of the part 6 is The calculation for determining the relative position with respect to the position of the hole 8 is as follows.

dx=x9-x8 dy=ylO-y8 dz=((x9-χ10) +(y9- ylO)
) /2 However, this calculation is valid only when the angle between the light emitting direction of the light source 2 and the reflecting surface and the angle between the light receiving direction of the camera 3 and the reflecting surface are each 1 degree and 45 degrees.

However, in reality, it is difficult to set the light source 2 and camera 3 at an accurate angle of 45 degrees or to arrange them orthogonally. After doing so and obtaining the respective coordinates a and b, the robot 1 is operated to move the part 6 by a predetermined amount, and the shadows 9 and 10 are recognized again to obtain the respective coordinates A and B. here,
To simplify the explanation, the movement by a predetermined amount will be described as a downward movement.

FIGS. 7 and 8 are explanations of input images when the part 6 is lowered by a predetermined amount. The tip of the component 6 is located on the internal division point C of the ratio of the distances aA and bB or the intersection C on the extended line of aA and bB. If the coordinates of the position of hole 8 are d, hector v=d
By performing the correction operation by -c, the tip of the component 6 and the hole 8 of the workpiece 7 can be aligned.

Next, the control operation of the central control section 11 for determining the relative positional relationship between the tip of the component 4 and the hole 8 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 I3,
Screen coordinate values d, a, and b of the position of the hole shape pattern 8 and the position of the shadow 9.10 at the tip of the component 6 are received from the image processing unit 13. Next, an operation command is sent to the moving mechanism control section 12 to cause it to move downward by a predetermined amount.

After the descending operation is completed, a recognition command is sent to the image processing unit 13 again,
Screen coordinate values A and B of shadow 9 and shadow 10 at the tip of the component are received. Find the coordinates C of the tip position of the part 6 from a, A, b, and B, and find the relative positional relationship between the tip of the part 6 and the hole from C and d.
Based on this, the amount of movement of the robot 1 is calculated so that the tip of the part 6 moves to the hole 8 position, and a movement command is sent to the moving mechanism control section 12.

The relative positional relationship between the tip of the part 6 as a moving object and the hole 8 of the workpiece 7 as a target object is as follows when the light #2 and the camera 3 are arranged facing each other, and when the light source 2 and the camera 3 are arranged orthogonally, respectively. Calculated according to the procedure explained above, (dx, dy, dz) is obtained as a relative position in the image coordinate system, and then the coordinates of the robot 1 as a moving mechanism are determined from the image coordinate system by the next calculation. Hector (rx,
ry, rz) are found.

(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 the target object is used as an insertion hole, two parts insertion robots can be used.

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 the predetermined position of the target object is a terminal, the present invention can be applied to 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.

Furthermore, since the position of the moving object and the target object can be determined simultaneously from the same human-powered image, visual feedback processing for the operation of the moving mechanism can be performed in a short time.

In addition, by determining the relative positional relationship between the moving object and the target object based on the direction and amount of movement of the shadow recognized when the moving object is moved a predetermined amount, it is possible to detect whether the tilt of the target object is slightly different each time. The same process can also be used to accurately determine the relative positional relationship, allowing accurate positioning.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a schematic configuration of a positioning device in an embodiment of the present invention, FIG. 2 is a block diagram showing a configuration of a controller, and FIGS. 3(a) to 3(d) are templates used for image processing. Figures 4 (a) and (b) are explanatory diagrams of the state of light projection from the light source onto the target object and the generated pattern. Figures 5 (a), (b), and (C) are diagrams showing the light source. An explanatory diagram of the pattern on the target object, the state in which the camera receives light, and the light reception pattern when the camera and the camera are placed facing each other, Fig. 6(a), (
b) and (C) are explanatory diagrams of the pattern on the target object, the state in which the camera receives light, and the light reception pattern when the light source and camera are arranged orthogonally, and Figures 7 and 8 are illustrations of the pattern on the target object when the light source and camera are arranged orthogonally. FIG. 9 is a flowchart of the control device for positioning operation. 1-------------One robot (moving mechanism)
2-・----111--------・Light source 3----
−−−−−−−−−−−One camera 5−−−−−−−−−−
−−・−−1−−Controller 6−−−−−−−−−−
−−−−−−・Parts (moving object) 7−・・−−−−−
−−−−−−−−− Work (target object) 8−・−−−
−−1−−−−−−−−・Hole (predetermined position of target object)
9−・−・−・−・−Shadow at the tip of the component due to light projection 10−・
---11------ ----------------Moving mechanism control section 13------m---------Image processing section.

Claims (2)

[Claims] (1) A positioning device that aligns a moving object moved by a moving mechanism to a predetermined position on the target object, which projects light onto the moving object and the target object in a direction that is not parallel to the perpendicular line drawn from the moving object to the target object. A light source, a camera that receives the reflected light of the light projection pattern on the target object at an angle different from the light projection direction of the light source, and an image processing means that calculates the relative positional relationship between the moving object and the target object from 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, and the image processing means is configured to control the shadow generated from the shape of the target object and the projected light. The object is configured to recognize the shadow generated when the light is blocked by a moving object and the shadow generated when the reflected light from the target object is blocked by the moving object to determine the relative positional relationship between the moving object and the target object. An alignment device featuring: (2) A claim characterized in that the accurate relative positional relationship between the moving object and the target object is determined based on the direction and amount of movement of the shadow recognized when the moving object is moved by a predetermined amount. 1. The alignment device according to 1.