JPH06218683A - Work position deflection detecting device - Google Patents

Abstract

PURPOSE:To provide a detecting device for the position deflection of a work which can be installed without reconstructing the already existing equipment and can detect the position deflection of the work during shift. CONSTITUTION:The shift quantity (x) of a work 6 is initiallized (step S204), and the value of the shift quantity (x) is calculated on the basis of the count value of the conveyor pulse (step S205). It is judged if the work 6 reaches the n-th standard position, i.e., the value of the shift quantity (x) obtained in the step S205 becomes equal to the distance L in the half of the viewfield of s camera 1 or not (step S206). After processings ranging from the step S205 to the step s206 are repeated until the result of the judgement becomes 'YES', the image data is compared in the step S207.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work position deviation detecting device suitable for use in a system for performing work on a moving work such as a coating robot system.

[0002]

2. Description of the Related Art In a painting line of an automobile or the like, it is necessary to detect the position of a work carried into a work space and control the operation of a painting robot so that an appropriate painting work corresponding to the work position is performed. There is. Here, when the work is moved in the work space by a conveyer such as a conveyer, the position of the work can be measured by counting the conveyer pulses generated each time a certain distance is conveyed, This measured data can be used to control the movement of the painting robot. However, when surging of the conveyor etc. occurs, the measured data of the work position will deviate from the actual position of the work, and using the measured data including such an error, it is possible to perform accurate painting work corresponding to the work position. I can't let the painting robot do it. In order to solve such a problem, it is necessary to detect the deviation between the work position obtained by measurement and the actual work position and feed it back to the robot controller to correct the robot operation.

In view of the above demands, the applicant of the present application has proposed a work position deviation detecting device using a plurality of one-dimensional sensors in Japanese Patent Application No. 61-193782. This work position deviation detecting device comprises a plurality of sets of light sources and a one-dimensional sensor which are arranged to face each other so as to sandwich a work stopped at a predetermined position in the work space. ON / O of each configured photodiode
The actual position of the work in the work space is detected based on the FF state.

Further, the applicant of the present invention is the Japanese Patent Application No. 62-152.
No. 650 proposes a work position deviation detecting device capable of detecting a work position deviation without stopping the work. This work position deviation detection device is configured by sequentially arranging a plurality of image sensors, which overlap each other on both sides of each measurement range, along a work conveyance path. According to this work position detecting device, the work carried into the work space is first detected by the first image sensor, then detected by the second image sensor, and so on. Are continuously detected by the cooperation of.

[0005]

However, the work position deviation detecting device according to the above-mentioned Japanese Patent Application No. 61-193782 detects the position deviation of the stopped work, so that it is continuously conveyed by the conveyor. There is a problem that it cannot be applied to a work to be transported. Further, when using this device, there is a problem that the process time becomes long because the work must be stopped every time the positional deviation is detected.

Further, since the work position deviation detecting device according to Japanese Patent Application No. 62-152650 detects a work by switching and using a plurality of image sensors according to the movement of the work, many images are detected. In addition to the sensors, a device and software for switching control between them are required, which makes the device large in size. Further, since this switching control is a complicated control linked with the conveyance of the work, it has a problem that it affects other control systems and reduces the efficiency of the system.

The present invention has been made in view of the above circumstances, and can be installed without modifying existing equipment, and moreover, it is possible to detect the positional deviation of a moving work. An object of the present invention is to provide a work position deviation detection device that can perform the work position deviation detection.

[0008]

In order to solve the above problems, a work position deviation detecting apparatus according to the present invention includes a camera for picking up an image of a work conveyed in a constant conveying direction, and a camera for detecting the work along the conveying direction. A storage device that stores, as reference image data, each image captured by the camera when arranged at different positions, and the storage device that stores the reference image data corresponding to the position of the work detected by the work position detection means. And a calculation means for calculating the deviation amount of the position of the work detected by the work position detection means by comparing the reference image data with the image data of the moving work photographed by the camera. It is characterized by having.

[0009]

According to the above structure, the reference image data corresponding to the current position of the work is read from the storage device, and the reference image data is compared with the image data of the moving work photographed by the camera. Thus, the amount of displacement of the work position is calculated.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. A: Configuration of Embodiment FIG. 1 is an overall view of this embodiment, and FIG. 2 is A in FIG.
It is a sectional view taken along the line A-A '. In these drawings, reference numeral 6 denotes an automobile body serving as a work, which is conveyed in a work space of a painting robot (not shown) by a conveyor 10 in an arrow direction in the drawings.

Further, a conveyor pulse is generated each time the work 6 is conveyed by the conveyor 10 for a predetermined distance, and the position of the work 6 can be obtained by counting the conveyor pulses.

The work position deviation detecting apparatus according to the present embodiment detects the deviation of the position of the work 6 from the actual value obtained by counting the conveyor pulses in this way, and is constituted by the elements described below. There is. First, reference numeral 1 denotes a camera, which is arranged on a side portion of the conveyor 10 and images the work 6 passing in front of it and outputs it as image data. An illumination 2 for illuminating the work 6 is attached to the camera 1. Further, 4 is a power source for supplying electric power to the illumination 2. An optical sensor 3 is provided to detect the arrival of the work 6 in the work space. Reference numeral 7 denotes a storage device, which stores a plurality of reference image data used for detecting the positional deviation for each vehicle type of the work 6.

Here, the reference image data is image data that will be obtained from the camera 1 when the work 6 is accurately arranged at each reference position set on the conveyance path. Figure 3
The concrete contents of these reference image data are illustrated in FIG.
In this figure, p0 to p9 refer to the workpiece 6 at the reference position x0 to
Each of the reference image data stored in the storage device 7 is an image captured by the camera 1 in each case of being arranged at x9, and represents each of these images p0 to p9. FIG. 7 is an enlarged view of the image p1 out of the images p0 to p9. Since the plurality of reference image data are determined for each vehicle type, when the vehicle type changes, a series of reference image data corresponding to the vehicle type is selected as the data for detecting the displacement.

The operation of storing these reference image data in the storage device 7 will be described later. An image processing device 5 monitors the position of the work 6 obtained by counting the conveyor pulses, and reads the reference image data corresponding to the reference position from the storage device 7 each time the work position matches the reference position. The positional deviation of the work 6 is calculated by comparing with the image data obtained from 1.

FIG. 5 shows how the reference image data is switched as the work 6 moves. The graph shown on the right side of FIG.
4 shows the relationship between the elapsed time t after the detection of “t” and the movement distance x of the work 6. On the other hand, on the left side of FIG.
Although rectangles with numbers “0” to “10” are described, these rectangles respectively represent reference image data, and the range surrounded by the upper and lower sides of each rectangle is the reference image data. It shows the range of the image of the corresponding work 6, and its length corresponds to the visual field of the camera.

On the leftmost side of FIG. 5, a scale is shown to show which part of the work 6 each reference image data corresponds to. The range of the image according to each reference data is also shown in the graph on the right side of FIG. 5 by symbols such as ×, Δ, and ●. Among these, x is the reference image whose number is shown on the right side. The work position for which the positional deviation is detected using the data, that is, the above-mentioned reference position is shown.
Further, Δ indicates a work position where the reference image data is switched to new reference image data in preparation for the next positional deviation detection, and ● indicates a portion of each part of the workpiece 6 corresponding to the reference image data used for the positional deviation detection of the camera. It represents the position of the work that leaves the field of view.

In FIG. 5, assuming that the range of each reference image data (field of view for one screen) is 2L and the overlapping range of two continuous reference image data is ΔL, the movement amount x of the work 6 is , The relationship with the number n of the reference image data to be used at the work position is expressed by the following equation. x = n × (2L−ΔL). ． ． (1)

The conditions for the image processing device 5 to switch the reference image data used for detecting the positional deviation are as follows. x = L + n × 2L−ΔL. ． ． (2)

B: Operation of Embodiment Next, the operation of the embodiment will be described with reference to the drawings.
In order to detect the positional deviation of the work 6 with this device,
It is necessary to perform a teaching process of storing reference image data corresponding to each reference position in the storage device 7. The teaching process will be described below with reference to the flowchart of FIG.
First, in step s101, the worker does the work 6
Set so that the tip of is in the center of the field of view of the camera 3.
Then, the process proceeds to step s102. In step s102, the initial screen p0 is photographed by the camera 1 and stored in the storage device 7 as the 0th reference image data via the image processing device 5.

Next, in step s103, the work 6 is advanced in the traveling direction of the conveyor by the camera field of view 2L, and in consideration of the occurrence of surging of the conveyor, it is returned by ΔL in the opposite direction to the traveling direction. . Then, the process proceeds to step s104.

In step s104, the image p1 shown in FIG. 3 is photographed by the camera 1 and stored in the storage device 7 as the first reference image data via the image processing device 5. Next, in step s105, it is determined whether or not the screen of the work 6 is the final screen, that is, the storage of the reference image data of the screen p9 is completed. This judgment result is "NO"
In the case of, it returns to step s103 and step s10
The processing from 3 to step s105 is repeated until the determination result of step s105 becomes “YES”. When the reference image data corresponding to all the reference positions is stored in the storage device 7 in this way, the determination result of step s105 becomes "YES", and the teaching process ends.

Next, the positional deviation detection will be described in more detail with reference to FIGS. When the work 6 is put into the work space, a command for instructing the image processing device 5 to detect the positional deviation of the work 6 is sent. As a result, the image processing apparatus 5 executes the routine whose flow is shown in FIG. First, in step s201, the measurement flag is turned off. Next, in step s202, it is determined whether or not the light beam of the optical sensor 3 is blocked by the work 6, and the determination in step s202 is repeated until the determination result is "YES". When the work 6 blocks the light beam of the optical sensor 3,
If "YES" is determined in step s202, the process proceeds to step s203, and the measurement flag is turned on.

Next, in step s204, the movement amount x of the work 6 is initialized, and then the process proceeds to step s205. In step s205, the value of the movement amount x is calculated based on the count value of the conveyor pulse, and then the process proceeds to step s206. In step s206, it is determined whether or not the work 6 has reached the 0th reference position, that is, whether or not the value of the movement amount x obtained in step s205 has become the distance L which is half the visual field of the camera 1. To do. If the result of this determination is "NO", then step s2
Returning to step 05, the processes of steps s205 and s206 are repeated until "YES" is determined in step s206. When it is determined in step s206 that the work 6 has moved by the distance L, the process proceeds to step s207.

In step s207, the 0th reference image data (screen p0) and the image captured by the camera 1 at that time are compared to calculate the deviation amounts Δx0 and Δy0 of the latter with respect to the former. Here, when comparing both images, mask processing is performed on both sides of the current image as shown in FIG. 8 to facilitate comparison with the reference image data.

Since it is more advantageous to process an object in which a mask image is applied to both ends of the screen than to image-process an object reflected in the entire field of view of the camera 1 in order to shorten the processing time and improve the accuracy. Is. And
The shift amount thus obtained is transferred to the control device of the work robot using a communication cable (not shown). As a result, the operation of the painting robot is corrected based on the amount of deviation.

Next, in step s209, the reference image data is switched by adding "1" to n (n = "0" in this case). Then, in step s210, it is determined whether or not n is larger than the number of reference image data. In this case, since n = “1”, the determination result is “NO” and the process returns to step s205.

Returning to step s205, the movement amount x of the work is calculated again. Next, in step s206,
In step s206, whether the work 6 has reached the first reference position, that is, step s206
The value of the movement amount x obtained in step 2 is “L + n × 2L−ΔL =
3L-ΔL "is determined. If the result of this determination is "NO", the flow returns to step s205, and the processes of steps s205 and s206 are repeated until "YES" is determined in step s206.

When the determination result of step s206 becomes "Yes", the process proceeds to step s207 and the first reference image data (screen p1) is compared with the image photographed by the camera 1 at that time to compare the former. The latter deviation amounts Δx1 and Δy1 are calculated and transferred to the control device of the work robot using a communication cable (not shown). As a result, the operation of the painting robot is corrected based on the amount of deviation.

Next, in step s209, n is "1".
Is added to switch the reference image data. Then, in step s210, it is determined whether or not n is larger than the number of reference image data. In this case, n = “2”
Therefore, the determination result is “NO” and step s2
Return to 05. After that, the determination result of step s210 is “Y
The processing similar to the above is repeated until it becomes "es", and when the processing is completed for all n, the determination result of step s210 becomes "Yes", and this routine is completed.

[0030]

As described above, according to the present invention, it is possible to detect the positional deviation of the moving workpiece with a simple device configuration without changing the existing equipment.

[Brief description of drawings]

FIG. 1 is an overall view of an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line A-A ′ in FIG.

FIG. 3 is a diagram showing a teaching screen according to an embodiment of the present invention.

FIG. 4 is a flowchart showing a teaching procedure according to an embodiment of the present invention.

FIG. 5 is a graph showing a camera visual field and a moving distance according to an embodiment of the present invention.

FIG. 6 is a flowchart showing a processing procedure of an embodiment of the present invention.

FIG. 7 is a diagram showing a teaching screen according to an embodiment of the present invention.

8 is a diagram showing an example of a current screen corresponding to FIG.

[Explanation of symbols]

 1 Camera 2 Illumination Device 3 Optical Sensor 4 Light Source Power Supply 5 Image Processing Device (Computing Unit) 6 Work 7 Storage Device (Storage Device)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location G05D 3/12 K 9179-3H

Claims (1)

[Claims] 1. A camera for picking up an image of a work conveyed in a constant conveyance direction, and reference images of respective images taken by the camera when the work is arranged at different positions along the conveyance direction. And a reference image data corresponding to the position of the work detected by the work position detection means are read from the storage device, and the reference image data and the image data of the moving work photographed by the camera By comparing with
A work position deviation detecting device comprising: a calculation unit that calculates a deviation amount of the position of the work detected by the work position detection unit.