JP2010117815A - Workpiece identification method and workpiece identification device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten a processing time when recognizing the type and attitude of a workpiece from a camera image. <P>SOLUTION: In a workpiece identification method for identifying a plurality of types of workpieces Wi to be supplied with random attitudes, to one external face F of the workpieces Wi, to one external face F of the workpiece Wi, a basic mark having orientation and different for each workpiece Wi is imparted, and to the other external face F of the workpiece Wi, a derived mark with the basic mark deformed so as to be identifiable for each external face F is imparted, and the robot is provided with: an imaging means 12 for picking up the image of the mark; and a master image storage means 42 for storing a master image M for the mark. This workpiece identification method includes: an image input stage S3 for fetching a mark image P to be picked up by the imaging means 12; an image comparison stage S4 for comparing the fetched mark image P with the master image M, and for detecting a matching level or a difference; and a determination stage S5 for determining the type and attitude of the workpiece Wi from the comparison result obtained by the image comparison stage S4. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a workpiece identification method and a workpiece identification device in a robot that performs work on a plurality of types of workpieces supplied in a random posture.

  In various production sites, robots are frequently used to appeal for speeding up and efficiency of work. When supplying a work, which is a work object, to a robot, it is common to supply one kind of work after alignment or positioning. However, in recent years, in order to improve production efficiency, the work alignment or positioning process is omitted, and multiple types of work are supplied at random, and the robot itself recognizes the type and posture of the work and works on the necessary part. It is required to be implemented.

  As a method for recognizing the type and posture of a workpiece, for example, a method is known in which the contour of a workpiece is regarded as a contour parameter and contour matching is performed with a contour parameter database. As a method of recognizing the position and orientation of the target object (work), the target object (work) given three-dimensional numerical data is regarded as a plurality of postures by the camera, and the contour function is calculated from the contour point of the target object (work). Is calculated and a contour function database is created. Then, a target object (work) in real space is imaged with a camera, and a contour function is extracted from the camera image. An image estimation method has been proposed in which a correlation coefficient is calculated using Fourier transform for the correlation between the extracted contour function and the contour function stored in the database, and the position and orientation of the target object are estimated from the result. (For example, refer to Patent Document 1). The above-described method can also be applied when estimating the type of the target object (work).

JP 2004-326314 A

  However, in the above method, when obtaining a contour function from the camera image of the target object, or when obtaining a correlation between the obtained contour function and the contour function database, the amount of data is increased or complicated calculation processing is performed. There is a problem that a lot of calculation time is required.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  (Application Example 1) A workpiece identification method for recognizing the type and posture of a workpiece in a robot that performs work on a plurality of types of workpieces supplied in a random posture, wherein the workpiece has a plurality of outer surfaces. Yes, one outer surface has directionality and is given a different type of basic mark for each type of workpiece, and the other outer surface is given a derived mark that is a deformed base mark that is identifiable for each outer surface. The robot includes at least an imaging unit that images the basic mark and the derived mark of the workpiece, and a master that stores in advance a master image captured by the imaging unit with respect to the basic mark and the derived mark. An image storage unit, and an image input step for capturing a basic mark image and a derivative mark image captured by the imaging unit; Comparing the inserted basic mark image and the derived mark image with the master image stored in the master image storage means to detect a degree of coincidence or a difference, and the image comparing step. And a determination step of determining the type and posture of the workpiece from the comparison result obtained.

  (Application Example 2) In the image comparison step, the basic mark image and / or the derived mark image and the master image are sequentially compared, and the basic mark image and / or the derived mark image match the maximum. Detecting the master image and recognizing the type of the basic mark image and / or the derived mark image, and detecting a difference in direction or angle between the basic mark image and / or the derived mark image and the master image; In the determining step, the type and posture of the workpiece are recognized from the difference in type, direction and angle of the basic mark and the derived mark.

  According to these methods, the workpiece is provided with different types of basic marks for each type. Also, the workpiece is provided with a derived mark that is deformed so that the basic mark can be identified for each outer surface. Therefore, the type of the mark can be recognized by comparing the basic mark image or derivative mark image picked up by the image pickup means with a master image based on the basic mark or derivative mark prepared in advance. As a result, it is possible to identify the type of work to which the mark is given.

  Further, by comparing the basic mark image or the derived mark image with the master image, it is possible to easily determine which outer surface of the work faces in the direction in which the imaging means is provided. That is, the direction of the workpiece can be determined. Further, by comparing the degree of coincidence or difference with the master image, it is possible to determine which direction the mark having directionality indicates or how much it is inclined. As a result, it is possible to easily determine the direction, direction, inclination, and angle of the workpiece provided with the mark. Therefore, the type and posture of the workpiece can be identified with a small amount of data. In addition, the type and posture of the workpiece can be recognized in a short time without performing complicated calculation processing.

  (Application example 3) The work identification method described above, wherein the basic mark and the derived mark are formed in an asymmetric shape.

  According to this method, the basic mark and the derived mark are directional and have an asymmetric shape. Therefore, when the mark image and the master image are compared, the degree of coincidence or the difference can be easily recognized. Further, it is possible to easily determine the direction of the mark, the vertical / horizontal relationship, the inclination, and the like.

  (Application Example 4) The work identification method described above, wherein the derived mark is configured in a different color from the basic mark.

  According to this method, a derived mark can be easily created for a basic mark. Further, by identifying the color of the derivative mark, it can be easily determined which outer surface faces the direction in which the imaging means is provided. Therefore, the types of marks given to the workpiece can be reduced, and the type (data amount) of the master image can be reduced. As a result, the time for comparing the mark image and the master image in the image comparison process can be reduced.

  (Application example 5) A workpiece identification device for recognizing the type and posture of a workpiece in a robot that performs work on a plurality of types of workpieces supplied in a random posture, wherein the workpiece has a plurality of outer surfaces. Yes, one outer surface has directionality and is given a different type of basic mark for each type of workpiece, and the other outer surface is given a derived mark that is a deformed base mark that is identifiable for each outer surface. Imaging means for imaging the basic mark and the derived mark of the workpiece, a master image storage unit for preliminarily storing a master image captured by the imaging means for the basic mark and the derived mark, An image input unit that captures the basic mark image and the derivative mark image captured by the imaging unit, the captured basic mark image, and the An image comparison unit that detects a degree of coincidence or a difference by comparing a raw mark image and the master image stored in the master image storage unit, and a type of the workpiece based on a comparison result obtained by the image comparison unit And a determination unit for determining the posture.

  Application Example 6 In the image comparison unit, the basic mark image and / or the derived mark image and the master image are sequentially compared, and the basic mark image and / or the derived mark image match the maximum. Detecting the master image and recognizing the type of the basic mark image and / or the derived mark image, and detecting a difference in direction or angle between the basic mark image and / or the derived mark image and the master image; The work identification apparatus according to claim 1, wherein the determination unit recognizes the type and posture of the work based on a difference in type, direction, and angle of the basic mark and the derived mark.

  According to these apparatuses, the work is provided with different types of basic marks for each type. Also, the workpiece is provided with a derived mark that is deformed so that the basic mark can be identified for each outer surface. Therefore, the type of the mark can be recognized by comparing the basic mark image or derivative mark image picked up by the image pickup means with a master image based on the basic mark or derivative mark prepared in advance. As a result, it is possible to identify the type of work to which the mark is given.

  Further, by comparing the basic mark image or the derived mark image with the master image, it is possible to easily determine which outer surface of the work faces in the direction in which the imaging means is provided. That is, the direction of the workpiece can be determined. Further, by comparing the degree of coincidence or difference with the front master image, it is possible to determine which direction the mark having directionality indicates or how much it is inclined. As a result, it is possible to easily determine the direction, direction, inclination, and angle of the workpiece provided with the mark. Therefore, the type and posture of the workpiece can be identified with a small amount of data. In addition, the type and posture of the workpiece can be recognized in a short time without performing complicated calculation processing.

  (Application example 7) The workpiece identification apparatus, wherein the basic mark and the derived mark are formed in an asymmetric shape.

  According to this apparatus, the basic mark and the derived mark are directional and have an asymmetric shape. Therefore, when the mark image and the master image are compared, the degree of coincidence or the difference can be easily recognized. Further, it is possible to easily determine the direction of the mark, the vertical / horizontal relationship, the inclination, and the like.

  (Application example 8) The workpiece identification apparatus, wherein the derived mark is configured in a different color from the basic mark.

  According to this apparatus, it is possible to easily determine which outer surface faces the direction in which the imaging means is provided by identifying the color of the derived mark that is easily created based on the basic mark. . Therefore, the shape of the mark given to one work can be made the same. Therefore, the types of marks given to the workpiece can be reduced, and the type (data amount) of the master image can be reduced. As a result, the time for comparing the mark image and the master image in the image comparison unit can be reduced.

(About work identification device)
A workpiece identification apparatus to which the workpiece identification method of the present invention is applied will be described with reference to FIG. FIG. 1 is a diagram illustrating a configuration example of a work identification device.

  As shown in FIG. 1, the workpiece identification device 1 includes a workpiece placement unit 5, a robot 10, and a control unit 20 that controls the robot 10. The workpiece placing unit 5 holds a workpiece W that is a work target to which a mark to be described later is given. Then, work by the robot 10 is performed in the workpiece placement unit 5. The workpiece W is transported by the belt conveyor 7 and is carried into the workpiece placement unit 5 where the work is performed by the robot 10 and then carried out to the next workpiece placement unit 5 or the next process.

  In this operation, a plurality of types of workpieces W are loaded in random postures, and specific operations are performed on the respective workpieces W. That is, in order to improve production efficiency and generalize and simplify the equipment, a plurality of types of workpieces W are operated by one robot 10 and no workpiece W alignment device or positioning device is provided.

  The robot 10 includes a camera 12 as an imaging unit, a robot hand 14, robot arms 16 and 17, and a joint portion 18. The robot 10 is a so-called articulated robot, and the robot arms 16 and 17 are freely movable with the joint portion 18 as a fulcrum. Then, work is performed on the workpiece W by the robot hand 14. The camera 12 functions as an eye of the robot 10, and recognizes the type, position, posture, work site, and the like of the work W.

  The control unit 20 includes at least an image processing device 30, a storage device 40, and a computer 50. The image processing device 30 includes at least an image input unit 32, an image comparison processing unit 34, and a camera position control unit 36. The storage device 40 includes at least a master image storage unit 42 and a recognition result storage unit 44. The computer 50 functions as a central processing unit, and controls the robot 10, the image processing device 30, the storage device 40, and the like as a whole. The operation of the control unit 20 will be described later.

(About work)
Here, a workpiece | work is demonstrated with reference to FIG. 2 and FIG. FIG. 2 is a diagram showing an example of a workpiece to which a mark is given, and FIG. 3 is a diagram showing examples of other workpieces.

  In the present embodiment, a plurality of types of workpieces Wi (i is a natural number representing the type of workpiece W) are applied. As shown in FIG. 2, a work W1 which is one type of work Wi is, for example, a hexahedron in which rectangular faces are parallel to each other, that is, a brick shape, part of four side faces from the top side. Each is formed into a shape that is cut off obliquely at different angles. That is, the workpiece W1 has directionality in the vertical direction, the front-rear direction, and the left-right direction. In the following, regarding each outer surface F of the workpiece Wi, a front view of the surface F3 shown in FIG. 2 is a front view, the top surface is F1, the bottom surface is F2, the front surface is F3, the rear surface is F4, the right surface is F5, The left side is called F6.

  As shown in FIG. 3A, the workpiece W2, which is another type of the workpiece Wi, is formed in a shape that is not cut off from the top surface F1 to the left surface F6 with respect to the workpiece W1 shown in FIG. Yes. That is, the workpiece W2 has one slope less than W1. As shown in FIG. 3B, the workpiece W3 is connected to the workpiece W1 by, for example, an arc instead of a flat surface from the top surface F1 to the left surface F6. That is, the workpiece W3 is different in one slope shape from W1. In this way, the workpieces Wi are configured in different types. Further, a mark is given to the outer surface F of these workpieces Wi.

(About the mark)
Next, marks given to the workpiece will be described with reference to FIG. FIG. 4 is a diagram for explaining marks.
As shown in FIG. 4A, the mark C has, for example, a deformed arrow shape. That is, in the arrow Ai (i is a natural number representing the type of arrow), the portion corresponding to the arrow blade b of the arrow is formed only on one side of the arrow bamboo. That is, the arrow Ai as the mark C is formed in an asymmetric shape. The arrows Ai are identified by the number of arrow blades b. Moreover, the up-down direction in FIG. 4 is represented by the direction of arrow a of arrow Ai, and the right and left in FIG. The arrow Ai corresponds to a basic mark.

  Further, the arrows Ai are formed in a plurality of different colors in the same arrow Ai. For example, the arrow Ai as the basic mark C is formed in black, and the other arrows Ai are colored in red, blue, green, yellow, and white, respectively. Hereinafter, these arrows Ai are represented as arrows Ai (black), arrows Ai (red), arrows Ai (blue), arrows Ai (green), arrows Ai (yellow), arrows Ai (white) for each color, Collectively, it is represented by an arrow Ai (color). This arrow Ai (color) corresponds to a derivative mark.

  An arrow Ai as a basic mark is printed on a part of the top surface F1 as the outer surface of one of the workpieces Wi, for example, in a small black color. That is, as shown in FIG. 2, an arrow A1 having one arrow blade b is added to the top surface F1 of the workpiece W1. Further, the arrow A2 having two arrow blades b is given to the top surface F1 of the work W2 shown in FIG. 3, and the arrow A3 having three arrow blades b is given to the top surface F1 of the work W3. When there are many types of workpieces Wi, arrows Ai having numbers corresponding to the natural number i of the workpieces Wi are sequentially given. That is, the type of work Wi and the type of arrow Ai are in one-to-one correspondence, and the type of work Wi is specified by specifying the type of arrow Ai.

  Arrows Ai (colors) as derivation marks are respectively given to the other outer surfaces of the work Wi. That is, as shown in FIG. 2, for the workpiece W1, the arrow A1 (black) as the arrow A1 on the top surface F1, the arrow A1 (red) on the bottom surface F2, the arrow A1 (blue) on the front surface F3, the rear surface An arrow A1 (green) is given to F4, an arrow A1 (yellow) is given to the right face F5, and an arrow A1 (white) is given to the left face F6. For the workpiece W2 shown in FIG. 3A, the arrow A2 (black) as the arrow A2 on the top surface F1, the arrow A2 (red) on the bottom surface F2, the arrow A2 (blue) on the front surface F3, and the rear surface F4. Arrow A2 (green), arrow A2 (yellow) on the right surface F5, and arrow A2 (white) on the left surface F6.

  For the workpiece W3 shown in FIG. 3B, the arrow A3 (black) as the arrow A3 on the top surface F1, the arrow A3 (red) on the bottom surface F2, the arrow A3 (blue) on the front surface F3, and the rear surface F4. Arrow A3 (green), arrow A3 (yellow) on the right surface F5, and arrow A3 (white) on the left surface F6. That is, the outer surface F of the work Wi is specified by specifying the type (color) of the arrow Ai (color) so that each outer surface F of the work Wi and the type of the arrow Ai (color) correspond one-to-one. In the drawings, the arrow Ai and the arrow Ai (color) are enlarged and emphasized for easy understanding.

  At this time, on the top surface F1 and the bottom surface F2, the arrows F on the front surface F3, the rear surface F4, the right surface F5, and the left surface F6 have arrows on the front surface F3 so that the direction of the arrow ai (color) is from the left surface F6 to the right surface F5. The direction of the arrow a of Ai (color) is given so as to go from the bottom surface F2 to the top surface F1. In addition, the arrow Ai (color) arrow blade b is in the rear surface F4 direction on the top surface F1 and the bottom surface F2, and the arrow Ai (color) arrow blade b is in the left surface F6 direction on the front surface F3 and the rear surface F4. Thus, the right surface F5 and the left surface F6 are provided so as to be in the direction of the front surface F3. That is, by knowing the direction of the arrow ai and the direction of the arrow blade b of the arrow Ai (color) given to the outer surface F, the direction and direction of the surface F can be known.

(About the master image)
Here, the master image stored in the master image storage unit will be described with reference to FIG. FIG. 5 is a diagram illustrating an example of a master image.
Using the camera 12 shown in FIG. 1, a master image is prepared in advance for each of the marks C given to the above-described workpiece Wi when observed from the front. For example, using the camera 12 of the robot 10 of the workpiece identification device 1 shown in FIG. 1, the arrow a points as the arrow A1 as the mark C given to each outer surface F of the workpiece W1 shown in FIG. Then, the image is taken from the front to obtain a master image. Specifically, the position of the camera 12 is controlled by the camera position control unit 36 of the image processing device 30 of the control unit 20, and the camera 12 is positioned in front of each outer surface F of the workpiece W1 placed on the stage 5, respectively. Take an image.

  As a result, as shown in FIG. 5, a master image Mj (j is a natural number representing the type of master image for one work Wi) for the work W1 is obtained. The master image M1 was captured with the arrow A1 (black) on the top surface F1 of the workpiece W1, the master image M2 was captured with the arrow A1 (red) on the bottom surface F2, and the master image M3 was captured with the arrow A1 (blue) on the front surface F3. It is an image. Similarly, the master image M4 captures the arrow A1 (green) on the rear surface F4, the master image M5 captures the arrow A1 (yellow) on the right surface F5, and the master image M6 captures the arrow A1 (white) on the left surface F6. It is. In this case, the master images M1, M3, M5 and the master images M2, M4, M6 are different from each other in the direction of the arrow blade b of the arrow A1 (color) in FIG. In any master image M, the arrow a points upward. The master image M is stored in the master image storage unit 42 of the storage device 40 of the control unit 20 shown in FIG. For the workpiece W2 and the workpiece W3, a master image Mj is similarly created and stored in the master image storage unit 42.

(About work identification method)
Next, the work identification method of the present invention will be described with reference to FIGS. FIG. 6 is a flowchart showing the flow of the workpiece identification method, FIG. 7 is a diagram for explaining the workpiece identification method, and FIG. 8 is a diagram showing an example of the mark image. FIG. 9 is a diagram illustrating a comparison process between a mark image and a master image. Note that the X axis, the Y axis, and the Z axis shown in FIG. 7 indicate the X axis, the Y axis, and the Z axis that are the basis of absolute coordinates in the work of the robot 10. That is, in the movement control of the robot hand 14 of the robot 10, it is a coordinate axis serving as a basis for coordinates indicating positions such as a movement start point and a movement end point. In the present embodiment, the robot 10 is set at a position facing the XZ plane and facing the Y direction.

  This work identification method uses the above-described work identification device 1 to identify the type and attitude of a workpiece Wi that is loaded in a production line or the like in which a plurality of types of workpieces Wi are loaded in a random order and random posture. Is. As shown in FIG. 6, the workpiece identification method includes a workpiece carry-in step S1, a mark imaging step S2, a mark image input step S3, an image comparison step S4, and a determination step S5.

  In the work carrying-in process of step S1, the work Wi to which the above-mentioned mark C is given is conveyed by the belt conveyor 7 and carried into the work placing unit 5 in the work identification apparatus 1 shown in FIG. At this time, the workpieces Wi are carried in a random order and a random posture. Therefore, for example, as shown in FIG. 7 (a), what kind of work Wi is carried in, which outer surface F is directed in which direction, or other work Wi not shown in the figure, etc. It is not known how much the X axis, Y axis, and Z axis in FIG. Therefore, the process proceeds to step S2.

  In the mark imaging process of step S2 shown in FIG. 6, the mark C given to the carried-in work Wi is imaged using the camera 12 shown in FIG. First, the camera 12 of the robot 10 shown in FIG. 1 is directly opposed to the XY plane in FIG. 7A by the camera position control unit 36 of the image processing apparatus 30, and the mark C of the work Wi is indicated from the Z (+) direction. Image. In this case, since the mark Ca is given in the Z (+) direction, the mark Ca is photographed to obtain the mark image P1 shown in FIG. Next, the camera 12 faces the XZ plane in FIG. 7A and images the mark C of the work Wi from the Y (−) direction. In this case, since the mark Cb is provided in the Y (−) direction, the mark Cb is photographed to obtain a mark image P3 shown in FIG. Next, the camera 12 faces the YZ plane in FIG. 7A and images the mark C of the workpiece Wi from the X (+) direction. In this case, since the mark Cc is given in the X (+) direction, the mark Cc is photographed to obtain a mark image P5 shown in FIG. That is, the mark C which opposes from the X-axis direction, the Y-axis direction, and the Z-axis direction as the absolute coordinate axes in FIG.

  In the mark image input process of step S3, the mark images P1, P3, and P5 captured by the camera 12 are taken into the image input unit 32 of the image processing device 30 of the control unit 20 shown in FIG.

  In the image comparison process in step S4 and the determination process in step S5, a comparison process between the captured mark image P and the master image M stored in the master image storage unit 42 and a determination process of the type and posture of the work Wi are performed. Done. The comparison process and the determination process are performed by the command and control of the computer 50 in the image comparison processing unit 34 of the control unit 20 shown in FIG.

  First, in the image comparison process in step S4, the verification is performed on the mark image P1 obtained in step S2. As shown in FIG. 9A, when the mark Ca in the mark image P1 is observed, the mark Ca is an arrow Aa, and the arrow Aa has one arrow blade b, and is colored black. Therefore, it can be seen that the arrow Aa is the arrow A1 given to the workpiece W1, and further the arrow A1 (black) given to the top surface F1. Therefore, the master image M1 obtained by capturing the arrow A1 (black) stored in the master image storage unit 42 is taken into the image comparison processing unit 34, and the mark image P1 and the master image M1 are compared. Then, the direction of the arrow aa in the direction of the arrow a is approximately the range of the X (+) direction in the same figure, but the inclination is α degrees different from the arrow A1 (black) of the master image M1. I understand. Also, it can be seen that the arrow blade b of the arrow Aa is oriented in the Y (+) direction.

  Next, the mark image P3 is compared and verified. As shown in FIG. 9B, when the mark Cb in the mark image P3 is observed, it can be seen that the mark Cb is an arrow Ab, and the arrow Ab has one arrow blade b and is colored blue. . Therefore, it can be seen that the arrow Ab is an arrow A1 (blue) given to the front surface F3 of the workpiece W1. Therefore, the master image M3 obtained by capturing the arrow A1 (blue) stored in the master image storage unit 42 is taken into the image comparison processing unit 34, and the mark image P3 and the master image M3 are compared. Then, it can be seen that the direction of the arrow Ab of the arrow Ab is the same as the Z (+) direction in the figure, and the inclination and the like are the same. Also, it can be seen that the arrow blade b of the arrow Ab is directed in the X (−) direction.

  Next, the mark image P5 is compared and verified. As shown in FIG. 9C, when the mark Cc in the mark image P5 is observed, it can be seen that the mark Cc is an arrow Ac, and the arrow Ac has one arrow blade b and is colored yellow. . Therefore, it can be seen that the arrow Ac is an arrow A1 (yellow) given to the right surface F5 of the workpiece W1. Therefore, the master image M5 obtained by capturing the arrow A1 (yellow) stored in the master image storage unit 42 is taken into the image comparison processing unit 34, and the mark image P5 and the master image M5 are compared. Then, it can be seen that the direction of the arrow Ac in the direction of the arrow Ac is substantially the same Z (+) direction range, but the inclination is different by β degrees compared to the arrow A1 (yellow) of the master image M5. Further, it can be seen that the arrow blade b of the arrow Ac is oriented in the Y (−) direction.

  In the determination step of step S5, it can be seen from the result of the comparison verification between the mark image P and the master image M obtained in the image comparison step of step S4 that the type of the workpiece Wi is the workpiece W1 shown in FIG. Regarding the posture of W1, as shown in FIG. 7B, the surface F to which the mark Ca is attached is the top surface F1, the surface F to which the mark Cb is attached is the front surface F3, and the mark Cc is It can be determined that the attached surface F is the right surface F5. This can be determined by using any combination of the type of arrow A, the direction of arrow a, and the direction of arrow blade b, or all of them. Also, the arrow A1 (black) on the top surface F1 is inclined by α degrees with respect to the X axis, the arrow A1 (blue) on the front surface F3 is not inclined with respect to the Z axis, and the arrow A1 (yellow) on the right surface F5. ) Is inclined by β degrees with respect to the Z axis, the inclination of the workpiece W with respect to the X axis (Y axis) and the Z axis can be known.

  That is, the workpiece Wi is the workpiece W1, and as shown in FIG. 7C, the top surface F1 is in the Z (+) direction, the front surface F3 is in the Y (−) direction, and the right surface F5 is in the X (+) direction. It is arranged for. Further, it can be seen that the workpiece W1 is inclined by α degrees with respect to the X axis in the XY plane and is inclined by β degrees from the Z axis in the YZ plane. The verification result is stored in the recognition result storage unit 44 of the storage device 40 of the control unit 20 shown in FIG. 1, and becomes the basic instruction command for the work of the robot 10 on the workpiece W1.

  Next, the process proceeds to step S6, where it is determined whether there is a workpiece Wi for which the posture is determined next. Next, when there is a work Wi for which the posture is determined (YES), the process proceeds to the above-described work carry-in process in step S1, and the above-described work is repeated. Next, when there is no work Wi for determining the posture (NO), the identification work is finished. In the above description, the case where the work Wi is the work W1 has been described as an example, but the image comparison process and the determination process are similarly performed when the work Wi is the work W2 or the work W3.

The effects of this example will be described below.
(1) According to the workpiece identification method using the workpiece identification device 1 described above, an arrow Ai as a different type of basic mark is given to the workpiece Wi for each type of workpiece Wi. Further, for each outer surface F of the workpiece Wi, an arrow Ai (color) as a derived mark that is colored in a different color with respect to the arrow Ai as a basic mark and can be identified is given. In addition, the arrow Ai and the arrow Ai (color) can show directionality and are formed asymmetrically.

  Then, in a production line or the like in which different types of workpieces Wi are supplied in a random order and a random posture, the arrow Ai or the arrow Ai (color) is displayed on the camera with respect to the workpiece Wi carried into the workpiece placement unit 5. 12 to obtain a mark image P. Then, the mark image P can be compared with a master image M of an arrow Ai or an arrow Ai (color) prepared in advance.

  Therefore, the type of the workpiece Wi can be identified by the type of the arrow Ai or the arrow Ai (color). Further, depending on the type of the arrow Ai or the arrow Ai (color), which outer surface F of the work Wi is directed in which direction, which direction the work Wi is directed by the direction indicated by the arrow a of the arrow A, the mark image P The direction in which the workpiece Wi is tilted can be determined by the difference in tilt between the arrow Ai or arrow Ai (color) of the master image M and the arrow Ai or arrow Ai (color) of the master image M. That is, the type and posture of the work Wi can be recognized by a simple operation of comparing the mark image P and the master image M. As a result, it is possible to recognize the type and posture of the work Wi with a small amount of data without performing complicated arithmetic processing using CAD / CAM data, contour functions, or the like. Accordingly, it is possible to shorten the calculation time for discriminating the type of the workpiece W and recognizing the posture, which can contribute to the production efficiency.

  As mentioned above, although embodiment of this invention was described, various deformation | transformation can be added with respect to the said embodiment in the range which does not deviate from the meaning of this invention. For example, modifications other than the above embodiment are as follows.

  (First Modification) In the above-described embodiment, the case where the mark image P is acquired for each outer surface F of the work Wi in the mark imaging process of step S2 shown in FIG. 6 has been described as an example, but the present invention is not limited to this. As shown in FIG. 10, which is a diagram for explaining the first modification, the mark image P may be acquired by looking down on the supplied workpiece Wi as it is. The mark image P0 shown in FIG. 10 is acquired with the camera 12 shown in FIG. 1 facing the upper part Q of the ridgeline between the front surface F3 and the right surface F5. By doing so, the arrow A1 (black) given to the top surface F1, the arrow A1 (blue) given to the front surface F3, and the arrow A1 (yellow) given to the right surface F5 are one mark image. Recorded at P0.

  Further, in creating the master image M, a plurality of master images M are created by capturing a plurality of marks C given to the work Wi by using the camera 12 shown in FIG. In the image comparison process in step S4 shown in FIG. 6, the captured mark image P0 is compared with the plurality of master images M stored in the master image storage unit 42, and the closest (highest matching) master is obtained. An image M is extracted. Then, the degree of coincidence and difference between the mark image P0 and the extracted master image M are compared and verified. In the determination step of step S5, the type and posture of the workpiece Wi are determined based on the above comparison verification result between the mark image P and the master image M obtained in the image comparison step of step S4. According to this method, the work of capturing the mark image P0 in the mark imaging step S2 can be simplified, and the time for determining the type and posture of the work Wi can be shortened.

  (Second Modification) In the above-described embodiment, the case where the arrow Ai with the arrow blades b having different positions and numbers is used as the basic mark has been described as an example. However, the present invention is not limited to this. The arrow Ai is an example, and various modifications and applications can be considered. For example, arrows J, K, L, etc. as shown in FIG. In other words, the marks need only be directional and formed in an asymmetric shape, and can be identified by applying a slight deformation. The arrows J, K, and L are identified by the number of line segments to be assigned. Further, the mark is not limited to an arrow. Even in these cases, the same effect as the above-described embodiment can be obtained.

  (Third Modification) In the embodiment described above, the case where the arrow Ai (color) formed in a different color with respect to the arrow Ai as the basic mark is used as the derived mark has been described as an example, but the present invention is not limited to this. The arrow Ai (color) is an example, and various modifications and applications can be considered. For example, the type or thickness of the line configured for the arrow Ai as the basic mark may be changed, or a new line or figure may be added. In other words, the marks need only be directional and formed in an asymmetric shape, and can be identified by applying a slight deformation. Further, the mark is not limited to an arrow. Even in these cases, the same effect as the above-described embodiment can be obtained.

  (Fourth Modification) In the above embodiment, the case where the workpiece W is carried into the stage 5 by a belt conveyor or the like has been described as an example, but the present invention is not limited to this. For example, the workpieces W may be stacked on a tray or the like. Even in this case, the same effect as the above-described embodiment can be obtained.

  (Fifth Modification) In the above-described embodiment, the case where the arrow Ai as the mark C is printed and applied to each outer surface F of the work Wi has been described as an example, but the present invention is not limited to this. The arrow Ai may be printed on a label and attached to each outer surface F. Further, each outer surface F may be stamped. It is only necessary that a mark having a directivity and an asymmetric shape is provided by some method so that each mark can be identified by applying a slight deformation. In the above-described embodiment, the case where the camera 12 as the imaging unit is provided as an integral part of the robot 10 has been described as an example, but the present invention is not limited to this. You may provide in the position which looks down at the robot 10 and the workpiece | work Wi in a production line. Even in these cases, the same effect as the above-described embodiment can be obtained. Moreover, the shape of the workpiece | work Wi demonstrated by the above-mentioned embodiment is an example, and is not limited to this. Various application variations are possible.

The figure which shows the structural example of a workpiece identification apparatus. The figure which shows an example of the workpiece | work to which the mark was provided. The figure which shows the example of the other workpiece | work. The figure explaining a mark. The figure which shows the example of a master image. The flowchart which shows the flow of the workpiece | work attitude | position recognition method. The figure explaining the workpiece posture recognition method. The figure which shows the example of a mark image. The figure explaining the comparison process of a mark image and a master image. The figure explaining a 1st modification. The figure which shows the modification of an arrow.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Work identification apparatus, 5 ... Work mounting part, 7 ... Belt conveyor, 10 ... Robot, 12 ... Camera as an imaging means, 14 ... Robot hand, 20 ... Control part, 30 ... Image processing apparatus, 32 ... Image input 34: Image comparison processing unit, 36: Camera position control unit, 40 ... Storage device, 42 ... Master image storage unit, 50 ... Computer, Ai ... Arrow as basic mark, Ai (color) ... Arrow as derivative mark , C ... mark, F ... outer surface, M, Mj ... master image, P ... mark image, S3 ... image input process, S4 ... image comparison process, S5 ... determination process, Wi ... work, a ... arrow, b ... arrow feather .

Claims (8)

A workpiece identification method for recognizing the type and posture of a workpiece in a robot that performs work on a plurality of types of workpieces supplied in a random posture,
The workpiece has a plurality of outer surfaces, one outer surface has directionality and a different type of basic mark is given to each type of workpiece, and the other outer surface can identify the basic mark for each outer surface. A modified derivative mark is attached to
The robot includes at least an imaging unit that images the basic mark and the derivative mark of the workpiece, and a master image storage unit that stores in advance a master image captured by the imaging unit with respect to the basic mark and the derivative mark. And having
An image input step of capturing a basic mark image and a derivative mark image imaged by the imaging means;
An image comparison step of comparing the captured basic mark image and the derived mark image with the master image stored in the master image storage means to detect a degree of coincidence or a difference;
And a determination step of determining the type and posture of the workpiece from the comparison result obtained in the image comparison step. In the image comparison step, the basic mark image and / or the derived mark image and the master image are sequentially compared to detect the master image that most closely matches the basic mark image and / or the derived mark image. Recognizing the type of the basic mark image and / or the derived mark image,
Detecting a difference in direction or angle between the basic mark image and / or the derived mark image and the master image;
The workpiece identification method according to claim 1, wherein in the determination step, the type and posture of the workpiece are recognized from a difference in type, direction, and angle of the basic mark and the derived mark.   The work identification method according to claim 1, wherein the basic mark and the derived mark are formed in an asymmetric shape.   The work identification method according to claim 1, wherein the derived mark is configured in a different color from the basic mark. A workpiece identification device for recognizing the type and posture of a workpiece in a robot that performs work on a plurality of types of workpieces supplied in a random posture,
The workpiece has a plurality of outer surfaces, one outer surface has directionality and a different type of basic mark is given to each type of workpiece, and the other outer surface can identify the basic mark for each outer surface. A modified derivative mark is attached to
Imaging means for imaging the basic mark and the derivative mark of the workpiece;
A master image storage unit that stores in advance a master image captured by the imaging unit with respect to the basic mark and the derived mark;
An image input unit for capturing a basic mark image and a derivative mark image captured by the imaging unit;
An image comparison unit that detects the degree of coincidence or difference by comparing the captured basic mark image and the derived mark image with the master image stored in the master image storage unit;
And a determination unit that determines a type and posture of the workpiece from a comparison result obtained by the image comparison unit. In the image comparison unit, the basic mark image and / or the derived mark image and the master image are sequentially compared to detect the master image that most closely matches the basic mark image and / or the derived mark image. Recognizing the type of the basic mark image and / or the derived mark image,
Detecting a difference in direction or angle between the basic mark image and / or the derived mark image and the master image;
6. The workpiece identification apparatus according to claim 5, wherein the determination unit recognizes the type and posture of the workpiece from the difference in type, direction, and angle of the basic mark and the derived mark.   The work identification device according to claim 5, wherein the basic mark and the derived mark are formed in an asymmetric shape.   The work identification apparatus according to claim 5, wherein the derived mark is configured in a different color from the basic mark.

Images