JP5659640B2 - Robot control apparatus, article take-out system, program, and robot control method - Google Patents

Description

  The present invention relates to a robot control device, an article take-out system, a program, and a robot control method.

In recent years, various industrial robots have been used in factory production lines and the like. In particular, since the (vertical) articulated robot has a structure similar to a human arm, it can perform various operations on behalf of a human.
For example, in Patent Document 1, an article take-out apparatus (separate stack) that can take out (pick) one by one using a multi-joint robot from a plurality of articles (work pieces) placed in a messy and overlapping manner (separated). A picking device) is disclosed. Such a picking apparatus can cope with various workpieces by a workpiece recognition processing program, an articulated robot control program, and the like. Therefore, it is suitable for a production line that handles various types of workpieces in a limited space, as compared with the case where a parts feeder corresponding to each workpiece is used.

Further, in the picking apparatus of Patent Document 1, after taking out one workpiece, first, only image data (two-dimensional information) is acquired, and the change in position and orientation is within an allowable range by comparing the image data before and after taking out. The presence or absence of the workpiece is judged. Then, by making such a determination, the number of time-consuming acquisitions of distance data (three-dimensional information) is reduced and the picking time is reduced.
On the other hand, for example, by using a hopper device (work separation device) disclosed in Patent Document 2, it is possible to facilitate the control of the articulated robot for taking out the workpiece. That is, by separating the workpieces so as not to overlap each other using the hopper device, the position and posture of the other workpiece can be prevented from changing before and after the removal of one workpiece. Therefore, each workpiece can be taken out in the vertical direction without re-acquiring the three-dimensional information.
In this way, it is possible to take out one by one from a plurality of workpieces using an articulated robot.

JP 2010-120141 A JP-A-10-29720

  In the picking apparatus of Patent Document 1, two-dimensional information is reacquired every time a workpiece is taken out. Furthermore, when there is no workpiece within the allowable range, it is necessary to reacquire three-dimensional information. However, for example, as shown in FIG. 13, after obtaining the two-dimensional information and three-dimensional information of the workpiece 9 in the camera area, the workpiece 9 is transported using the conveyor device 5, and the workpiece 9 is taken out in the picking area. If done, the information cannot be reacquired. For this reason, the picking device of Patent Document 1 cannot be applied to a production line or the like in which the camera area and the picking area are different.

Even when using a hopper device, the workpieces may not be completely separated and may be adjacent to each other. In this case, if the workpiece is taken out in the vertical direction as it is, the position and posture of another adjacent workpiece may be changed.
Furthermore, for example, as shown in FIG. 13, when the workpiece 9 has an uneven shape, even if the workpieces 9 do not overlap each other, they may appear to overlap each other in the vertical direction. In this case, out of the workpieces 9 (hereinafter referred to as workpieces A to E) labeled A to E, if the workpieces other than the workpiece C are taken out in the vertical direction, they interfere with other workpieces and change their positions and postures. End up.
Therefore, when the workpieces are not completely separated from each other, the position and posture of the other workpiece change before and after the removal of one workpiece. Reacquisition may be necessary.

  The main present invention for solving the above-described problems is to recognize a plurality of articles placed so as not to overlap each other and calculate a position and a posture, and a first article group composed of the plurality of articles. A horizontal position of the center of gravity of the first article is calculated as a first center of gravity position, and a selection unit that selects an article farthest from the first center of gravity position as the article to be taken out of the first article group; The horizontal position of the center of gravity of the second article group consisting of articles included in the region centered on the article to be taken out of the article group is calculated as the second center of gravity position, and the take-out target is calculated from the second center of gravity position. A moving direction calculating unit that calculates a direction toward the horizontal position of the center of gravity of the article as a horizontal movement direction, and moving the article to be taken out by a predetermined movement amount in the horizontal movement direction and then taking out in the vertical direction. A control unit for controlling the articulated robot as a robot controller and having a.

  Other features of the present invention will become apparent from the accompanying drawings and the description of this specification.

  According to the present invention, even when a plurality of articles placed so as not to overlap each other are not completely separated, they can be taken out using an articulated robot without reacquiring three-dimensional information. it can.

It is a block diagram which shows the structure of the robot control apparatus in one Embodiment of this invention. It is a block diagram which shows the outline of a structure of the whole article picking-up system provided with the robot control apparatus in one Embodiment of this invention. It is a flowchart explaining operation | movement of the program for making a computer implement | achieve the function of the recognition process part 11, the selection part 13, the moving direction calculation part 14, and the control part 15. It is a figure which shows an example of arrangement | positioning of the workpiece | work conveyed to the picking area. FIG. 5 is a diagram for explaining a method of calculating a center of gravity position CG of the entire workpiece from the workpiece arrangement shown in FIG. 4 and selecting a workpiece WS to be taken out. It is a figure explaining the method of calculating the gravity center position CL of the workpiece | work group of the vicinity of the workpiece | work W1. It is a figure explaining the method of calculating the horizontal movement direction DP of the workpiece | work W1. It is a figure explaining the method of calculating the gravity center position CG of the whole workpiece | work after selecting the workpiece | work W1, and selecting the workpiece | work WS of extraction object. It is a figure explaining the method of calculating the gravity center position CL of the workpiece | work group of the vicinity of the workpiece | work W4. It is a figure explaining the method of calculating the horizontal movement direction DP of the workpiece | work W4. It is a flowchart explaining operation | movement of the other program for making a computer implement | achieve the function of the recognition process part 11, the selection part 13, the moving direction calculation part 14, and the control part 15. It is a figure which shows an example of arrangement | positioning in the case of handling the workpiece | work conveyed to the picking area as a some workpiece | work group. It is a figure which shows an example of the arrangement | positioning of the workpiece | work which generate | occur | produces interference if it takes out as it is in the perpendicular direction.

  At least the following matters will become apparent from the description of this specification and the accompanying drawings.

=== Overall Configuration of Article Pickup System ===
Hereinafter, with reference to FIG. 2, an outline of a configuration of an entire article take-out system including a robot control device according to an embodiment of the present invention to be described later will be described.
The article take-out system shown in FIG. 2 includes a robot control device 1, a stereo camera 2, an articulated robot 3, a hopper device 4, and a conveyor device 5. In FIG. 2, the conveying direction of the conveyor device 5 is the right direction, and the same applies to the drawings other than FIG.

The stereo camera 2 is disposed above a camera area located on the relatively upstream side (left side in FIG. 2) of the conveyor device 5. Further, the three-dimensional information IMG output from the stereo camera 2 is input to the robot control device 1. Further, the control signal CNT output from the robot control device 1 is input to the articulated robot 3.
The articulated robot 3 includes a chuck portion 31 at the tip. Further, the articulated robot 3 is arranged so that the chuck portion 31 can be moved to a picking area located on the relatively downstream side (right side in FIG. 2) of the conveyor device 5.

The camera area has the same size as the picking area or larger than the picking area. Further, the camera area and the picking area are arranged so as to partially overlap or at least be adjacent to each other. In FIG. 2, both areas have the same size and are arranged adjacent to each other.
The hopper device 4 is disposed on the most upstream side of the conveyor device 5. Further, the work 9 is discharged from the hopper device 4 to the conveyor device 5.

=== Outline of the operation of the entire article take-out system ===
Hereinafter, an outline of the operation of the entire article take-out system will be described.
The hopper device 4 sequentially discharges the workpieces 9 to the conveyor device 5 so as not to overlap each other in synchronization with the conveying operation of the conveyor device 5. Further, the conveyor device 5 transports the workpiece 9 and stops once every time the workpiece 9 is transported by a predetermined length. The predetermined length is set such that after the work 9 is conveyed to the camera area and stopped, it is conveyed to the picking area and stopped. As described above, when the camera area and the picking area have the same size and are arranged adjacent to each other, the predetermined length is the length of each area in the transport direction.
On the other hand, the robot control device 1, the stereo camera 2, and the articulated robot 3 operate while the conveyor device 5 is stopped.

  The stereo camera 2 corresponds to a three-dimensional information acquisition device, images the workpiece 9 in the camera area, and outputs three-dimensional information IMG. Further, the robot control device 1 outputs a control signal CNT based on the three-dimensional information IMG acquired at the time of shooting in the camera area of the workpiece 9 currently in the picking area, that is, during the previous stop of the conveyor device 5. The articulated robot 3 is controlled according to the control signal CNT, and grips the workpieces 9 in the picking area with the chuck portion 31 and takes them out one by one.

  In this way, the articulated robot 3 can be controlled based on the three-dimensional information IMG acquired in the camera area, and the workpieces 9 conveyed to the picking area can be taken out one by one. When all the workpieces 9 in the picking area are taken out, the conveyor device 5 again conveys the workpieces 9 by a predetermined length. Note that three-dimensional information may be acquired using a camera and a laser scanner, for example, in the same manner as the picking apparatus disclosed in Patent Document 1, instead of the stereo camera 2.

=== Configuration of Robot Control Device ===
Hereinafter, with reference to FIG. 1, the structure of the robot control apparatus in one Embodiment of this invention is demonstrated. In the following description, each work is represented with a symbol Wk (k is a natural number).
The robot control device 1 shown in FIG. 1 includes a recognition processing unit 11, a storage unit 12, a selection unit 13, a movement direction calculation unit 14, and a control unit 15.

  The recognition processing unit 11 receives the three-dimensional information IMG, and the position / posture information T [Wk] output from the recognition processing unit 11 is input to the storage unit 12. Further, the gravity center position Ck output from the storage unit 12 is input to the selection unit 13, and the gravity center position CG and the selected workpiece WS are output from the selection unit 13. Further, the movement direction calculation unit 14 receives the center of gravity position Ck, the center of gravity position CG, and the selected workpiece WS, and the movement direction calculation unit 14 outputs the horizontal movement direction DP. The control unit 15 receives the selected workpiece WS, the horizontal movement direction DP, and the position / posture information T [WS] output from the storage unit 12, and the control unit 15 outputs the control signal CNT. Yes.

=== Operation of the robot controller ===
Hereinafter, the operation of the robot control apparatus according to the present embodiment will be described with reference to FIGS. 3 to 10 as appropriate. In the following, as an example, three-dimensional information IMG of eight workpieces W1 to W8 is acquired and input to the robot controller 1 in the camera area, and the workpieces W1 to W8 are transported to the picking area. The case will be described.

  In the robot control device 1, the functions of the recognition processing unit 11, the selection unit 13, the movement direction calculation unit 14, and the control unit 15 can be realized by a computer including the storage unit 12, for example. FIG. 3 shows the operation of a program for causing a computer to realize functions corresponding to the recognition processing unit 11, the selection unit 13, the movement direction calculation unit 14, and the control unit 15.

  When the three-dimensional information IMG of the entire workpieces W1 to W8 is input and the processing of the program is started (S11), first, position / posture recognition processing is performed, and position / posture information T [Wk] (1 ≦ 1) of each workpiece k ≦ 8) is calculated (S12). Specifically, for example, by extracting an edge from the three-dimensional (image) information IMG and performing matching with the three-dimensional information (3D-CAD data, etc.) of one workpiece, each workpiece is recognized and the position / Posture information T [Wk] is calculated. Therefore, the process of S12 realizes a function corresponding to the recognition processing unit 11. The position / posture information T [Wk] is stored in the storage unit 12 and is read out as appropriate.

  Here, an example of the arrangement of the workpieces W1 to W8 conveyed to the picking area is shown in FIG. In FIG. 4, gravity center positions C1 to C8 indicate horizontal positions of the gravity centers of the workpieces W1 to W8, respectively. When the position / posture information T [Wk] indicates the position of the center of gravity as the position of each workpiece, the vertical position is omitted from the position / posture information T [Wk] and the center of gravity position Ck is directly obtained. be able to. In other cases, the center-of-gravity position Ck can be calculated using relative coordinates with the position of each workpiece indicated by the position / posture information T [Wk] as the origin. Hereinafter, an operation when a workpiece is taken out from the arrangement will be described.

  First, when taking out the first workpiece, loop processing from S13 to S18 is performed with n = 1. In the loop processing, first, the horizontal position of the center of gravity of the entire workpieces W1 to W8 (first article group) is calculated as the center of gravity position CG (first center of gravity position) (S13). Specifically, for example, the average of the gravity center positions Ck of the workpieces can be calculated as the gravity center position CG. Further, for example, a plan view (orthographic projection onto the horizontal plane) of the workpieces W1 to W8 may be obtained from the three-dimensional (image) information IMG, and the center of gravity of the plan view may be calculated as the center of gravity position CG.

  Further, as shown in FIG. 5, the work farthest from the center of gravity position CG among the works W1 to W8 is selected as an object to be taken out (selected work WS) (S14). Therefore, the processing of S13 and S14 realizes a function corresponding to the selection unit 13. In FIG. 5, the workpiece W1 is selected as the selected workpiece WS, and the center of gravity C1 of the selected workpiece WS (work W1) is represented as CS.

  Next, an area centered on the selected workpiece WS is set as a neighborhood area, and the horizontal position of the center of gravity of a neighborhood workpiece group (second article group) composed of workpieces included in the neighborhood area among the workpieces W1 to W8 is defined as the center of gravity. Calculated as a position CL (second center of gravity position) (S15). Specifically, as shown in FIG. 6, for example, an area within one workpiece from the selected workpiece WS (work W1) is set as the neighborhood area, and the average of the gravity center positions Ck of the workpieces W1, W2, and W4 is set as the gravity center. It can be calculated as the position CL.

  Further, as shown in FIG. 7, the direction from the gravity center position CL toward the gravity center position CS is calculated as the horizontal movement direction DP (S16). Therefore, the processing of S15 and S16 realizes a function corresponding to the movement direction calculation unit 14.

  Finally, the control signal CNT is output based on the position / posture information T [WS] of the selected workpiece WS and the horizontal movement direction DP, and the selected workpiece WS is moved in the horizontal movement direction DP by a predetermined movement amount (S17). The articulated robot 3 is controlled so as to be taken out in the vertical direction (S18). Therefore, the processing of S17 and S18 realizes a function corresponding to the control unit 15. In FIG. 7, the predetermined movement amount is set to one work.

  As described above, the robot control device 1 selects the workpiece W1 that is farthest from the center of gravity position CG (located on the outermost periphery) as the first take-out object (selected workpiece WS), and the workpiece W1 is in the horizontal movement direction. Move the DP horizontally by one workpiece and then remove it in the vertical direction. Here, the direction from the center of gravity position CL of the neighboring workpiece group to the center of gravity CS of the selected workpiece WS is set as the horizontal movement direction DP, thereby preventing interference with other workpieces during horizontal movement. Further, by horizontally moving one workpiece in the horizontal movement direction DP and taking it out in the vertical direction, interference with other workpieces during vertical movement is prevented.

  Depending on the arrangement of the workpiece and the setting of the neighborhood area, only the selected workpiece WS may be included in the neighborhood area, and the horizontal movement direction DP from the gravity center position CL toward the gravity center CS may not be calculated. In this case, even if it is taken out in the vertical direction without moving horizontally, it does not interfere with other workpieces. Therefore, for example, the horizontal movement direction DP is not calculated, and is taken out in the vertical direction without moving in the horizontal direction. Of course, the vicinity area may be set so as to include at least one workpiece other than the selected workpiece WS, and the horizontal movement direction DP may be calculated. Further, if the horizontal movement direction DP cannot be calculated by setting a circular area having a radius equal to or greater than the movement amount at the time of horizontal movement from the selected work WS, the horizontal direction of selection DP cannot be calculated. Since the interference with other workpieces does not occur even when moved, a predetermined horizontal movement direction DP may be set.

  Furthermore, although the amount of movement during horizontal movement is sufficient for one workpiece regardless of the shape of the workpiece, it can be less than or equal to one workpiece. For example, in the case of the workpiece 9 shown in FIG. 13, interference can be prevented by horizontally moving the workpiece by ½ workpiece.

  After the first workpiece W1 is taken out, n = 2 and loop processing from S13 to S18 is performed. In the loop processing, first, the horizontal position of the center of gravity of the entire work W2 to W8 (first article group) excluding the taken out work W1 is calculated as the center of gravity position CG (first center of gravity position) (S13). ). Therefore, the average of the gravity center positions Ck of the workpieces W2 to W8 can be calculated as the gravity center position CG. Alternatively, the portion of the workpiece W1 may be masked in the plan view of the workpieces W1 to W8, and the center of gravity of the masked plan view may be calculated as the center of gravity position CG.

  Further, as shown in FIG. 8, the work farthest from the center of gravity position CG among the works W2 to W8 is selected as an object to be taken out (selected work WS) (S14). In FIG. 8, the workpiece W4 is selected as the selected workpiece WS, and the center of gravity C4 of the selected workpiece WS (work W4) is represented as CS.

  Next, an area centered on the selected workpiece WS is set as a neighborhood area, and the horizontal position of the center of gravity of a neighborhood workpiece group (second article group) composed of workpieces included in the neighborhood area among the workpieces W2 to W8 is defined as the center of gravity. Calculated as a position CL (second center of gravity position) (S15). Specifically, as shown in FIG. 9, for example, an area within one workpiece from the selected workpiece WS (work W4) is set as a neighborhood area, and the average of the gravity center positions Ck of the workpieces W4 and W2 is set as the gravity center position CL. Can be calculated. Further, as shown in FIG. 10, the direction from the gravity center position CL toward the gravity center position CS is calculated as the horizontal movement direction DP (S16).

  Finally, the control signal CNT is output based on the position / posture information T [WS] of the selected workpiece WS and the horizontal movement direction DP, and the selected workpiece WS is moved in the horizontal movement direction DP by a predetermined movement amount (S17). The articulated robot 3 is controlled so as to be taken out in the vertical direction (S18).

  Similarly, every time the selected workpiece WS is taken out, the robot controller 1 calculates the center of gravity position CG excluding the taken out workpiece and selects the next selected workpiece WS. Then, by performing the loop process from S13 to S18 eight times, all the workpieces W1 to W8 can be taken out, and the process is terminated (S19).

  In this way, even when the workpieces W1 to W8 discharged from the hopper device 4 and transported to the picking area so as not to overlap each other are not completely separated, they do not interfere with other workpieces. It can be taken out one by one. Therefore, all the workpieces can be taken out from the picking area using the articulated robot 3 without reacquiring the three-dimensional information IMG.

=== Other programs of the robot controller ===
In the above embodiment, the function of the robot control device 1 is realized by a computer including the storage unit 12, but is not limited thereto. Since a known mounting method can be used for the control unit 15 in the robot control device 1, a program that does not perform the processing of S17 and S18 in FIG. 3 is installed in the computer including the storage unit 12 and the control unit 15. May be.

  In the above embodiment, the robot control device 1 selects the selected workpiece WS one by one from the workpieces W1 to W8, and takes out the selected workpiece WS each time. However, the present invention is not limited to this.

  For example, as shown in FIG. 11, a program for controlling the articulated robot 3 may be installed after the loop processing corresponding to S13 to S16 in FIG. In this case, first, selection of the n-th (1 ≦ n ≦ 8) selected workpiece WSn and calculation of the horizontal movement direction DPn corresponding thereto are performed (loop processing 1), and then horizontal movement is performed in the order of the selected workpiece WSn. After moving horizontally in the direction DPn, it is taken out in the vertical direction (loop processing 2). By setting it as such a program, after confirming the result of selection of the selection workpiece | work WSn performed in advance and calculation of the horizontal movement direction DPn, taking-out of the selection workpiece | work WSn can also be started. Further, the loop processes 1 and 2 in FIG. 11 may be processed in parallel.

  In the loop processing 1, processing is performed using the position / posture information T [Wk] of the remaining workpieces excluding the workpiece whose horizontal movement direction has already been calculated in S23. Further, in S24, processing is performed using the position / posture information T [Wk] of the remaining workpieces excluding the workpiece whose horizontal movement direction has already been calculated.

  In the above-described embodiment, the entire work conveyed to the picking area is processed as one work group (first article group), but the present invention is not limited to this.

  For example, as shown in FIG. 12, when the workpieces conveyed to the picking area are relatively dispersed, three workpiece groups G1 to G3 (first article group) that are separated from each other by a moving amount during horizontal movement. Can also be processed. In this case, the processing shown in FIG. 3 or FIG. 13 is performed for each work group, all the works included in one work group are taken out, the process is terminated, and then the process proceeds to the next work group. By handling the workpieces conveyed to the picking area in this way as a plurality of workpiece groups and processing each workpiece group, in particular, when the multi-joint robot 3 includes a plurality of chuck portions, the process up to the next selected workpiece WS is performed. The moving distance can be shortened. If only one workpiece is included in the workpiece group as in the workpiece group G2 in FIG. 13, interference with other workpieces will not occur even if the workpiece is taken out in the vertical direction without being moved horizontally. Therefore, when the work group includes only one work, the horizontal movement direction DP is not calculated for the work group, and the work can be moved out in the vertical direction without being moved horizontally.

  As described above, in the robot control apparatus 1, the work farthest from the center of gravity position CG of the entire work is selected as the selected work WS, and the direction from the center of gravity CL of the neighboring work group to the center of gravity CS of the selected work WS is set horizontally. By calculating the movement direction DP and moving the selected workpiece WS by a predetermined movement amount in the horizontal movement direction DP and then taking it out in the vertical direction, the workpieces placed so as not to overlap each other are not completely separated. Even if it is a case, it can take out so that it may not interfere with other workpieces. Therefore, the workpieces conveyed to the picking area can be taken out one by one using the articulated robot 3 without reacquiring the three-dimensional information IMG.

  Further, every time the selected workpiece WS is taken out, the center of gravity position CG is calculated except for the taken out workpiece, and the next selected workpiece WS is selected, so that all the workpieces are picked up from the picking area using the articulated robot 3. It can be taken out.

  Further, the selection of the selected workpiece WSn is performed by selecting the selected workpiece WSn and calculating the horizontal movement direction DPn corresponding to the selected workpiece WSn in advance and horizontally moving the selected workpiece WSn in the horizontal movement direction DPn in the order of the selected workpiece WSn. Further, after confirming the calculation result of the horizontal movement direction DPn, it is possible to start taking out the selected workpiece WSn.

  In particular, the articulated robot 3 is handled by handling the workpieces transported to the picking area as a plurality of workpiece groups, taking out all the workpieces included in one workpiece group, and then proceeding to the processing of the next workpiece group. When a plurality of chuck portions are provided, the moving distance to the next selected workpiece WS can be shortened.

  Further, by calculating the average of the center of gravity position Ck of each workpiece as the center of gravity position CG of the entire workpiece, every time the selected workpiece WS is extracted, the center of gravity position CG is calculated from the center of gravity position Ck of each workpiece excluding the extracted workpiece. Can be calculated.

  Further, a plan view of the entire work is obtained from the three-dimensional (image) information IMG, and the center of gravity of the plan view is calculated as the center of gravity position CG. The part of the workpiece is masked, and the center of gravity position CG can be calculated from the masked plan view.

  Further, in the article take-out system shown in FIG. 2, the workpieces 9 are sequentially discharged from the hopper device 4 to the conveyor device 5 so as not to overlap each other, and the articulated robot 3 is moved based on the three-dimensional information IMG acquired in the camera area. By controlling, the workpieces 9 conveyed to the picking area can be taken out one by one.

  Further, in a program for causing a computer to realize functions corresponding to at least the recognition processing unit 11, the selection unit 13, and the movement direction calculation unit 14 of the robot control device 1, the three-dimensional information IMG of the entire workpiece acquired in the camera area. By recognizing each workpiece and calculating position / posture information T [Wk], the selected workpiece WS can be selected based on the position / posture information T [Wk] and the horizontal movement direction DP can be calculated. it can.

  Also, the center of gravity position CG of the entire workpiece is calculated, the workpiece farthest from the center of gravity position CG is selected as the selected workpiece WS, the center of gravity position CL of the neighboring workpiece group is calculated, and the center of gravity position CS of the selected workpiece WS is calculated from the center of gravity position CL. Is calculated as the horizontal movement direction DP, and the selected workpiece WS is moved in the horizontal movement direction DP by a predetermined movement amount and then taken out in the vertical direction, so that the workpieces placed so as not to overlap each other are completely Even if they are not separated, the workpieces conveyed to the picking area can be taken out one by one using the articulated robot 3 without re-acquiring the three-dimensional information IMG.

  In addition, the said embodiment is for making an understanding of this invention easy, and is not for limiting and interpreting this invention. The present invention can be changed and improved without departing from the gist thereof, and the present invention includes equivalents thereof.

1 Robot control device 2 Stereo camera (3D information acquisition device)
3 Articulated robot 4 Hopper device (work separation device)
DESCRIPTION OF SYMBOLS 5 Conveyor apparatus 9 Workpiece 11 Recognition processing part 12 Storage part 13 Selection part 14 Movement direction calculation part 15 Control part 31 Chuck part W1-W8 Workpiece

Claims (9)

A recognition processing unit for recognizing a plurality of articles placed so as not to overlap each other and calculating a position and orientation;
The horizontal position of the center of gravity of the first article group composed of the plurality of articles is calculated as the first center of gravity position, and the article farthest from the first center of gravity position is extracted from the first article group. A selection section to select as,
The horizontal position of the center of gravity of the second article group consisting of articles included in the region centered on the article to be taken out of the first article group is calculated as the second center of gravity position, and the second center of gravity position is calculated. A moving direction calculation unit that calculates a direction from the horizontal direction of the center of gravity of the article to be taken out as a horizontal moving direction;
A control unit for controlling the articulated robot so that the article to be taken out is moved in the horizontal movement direction by a predetermined movement amount and then taken out in the vertical direction;
A robot control apparatus comprising:   The selection unit calculates the first center-of-gravity position and removes the taken-out article every time the multi-joint robot takes out the taken-out article from the first article group. The robot control apparatus according to claim 1, wherein: The selection unit calculates the first center-of-gravity position and removes the next article to be taken out by removing the article to be taken out from the first article group every time the movement direction calculating unit calculates the horizontal movement direction. Select items
The movement direction calculation unit calculates the second center-of-gravity position from the first article group from which the articles for which the horizontal movement direction has already been calculated is removed, and associates the horizontal direction with the article to be taken out. Calculate the direction of movement,
The control unit moves the article to be taken out in the order selected by the selection unit by the predetermined movement amount in the horizontal movement direction associated with the article to be taken out, and then removes the article in the vertical direction. The robot control apparatus according to claim 1, wherein the articulated robot is controlled.   The selection unit sequentially selects one of the plurality of first article groups that are separated from each other by the predetermined amount of movement, and includes all of the selected first article groups. 4. The robot control device according to claim 2, wherein the first center-of-gravity position is calculated until an article is removed, and the article to be taken out is selected. 5.   The said selection part calculates the average of the horizontal position of each gravity center of the articles | goods contained in the said 1st article group as said 1st gravity center position, The said any one of Claim 1 thru | or 4 characterized by the above-mentioned. The robot control device described.   5. The robot control apparatus according to claim 1, wherein the selection unit calculates a centroid of an orthogonal projection of the first group of articles on a horizontal plane as the first centroid position. 6. . A robot controller according to any one of claims 1 to 6;
A conveyor device for conveying the plurality of articles;
A hopper device for discharging the plurality of articles to the conveyor device so as not to overlap each other;
A three-dimensional information acquisition device for acquiring three-dimensional information of the plurality of articles placed on the conveyor device;
The articulated robot that takes out the plurality of articles under the control of the control unit;
With
The article extraction system, wherein the recognition processing unit calculates positions and postures of the plurality of articles based on the three-dimensional information. A control unit that controls the articulated robot so as to move the article to be taken out of the plurality of articles placed so as not to overlap each other by a predetermined amount of movement in the horizontal direction and then to remove the article in the vertical direction; In a computer to which three-dimensional information of a plurality of articles is input,
A function of recognizing each of the plurality of articles based on the three-dimensional information and calculating a position and orientation;
A function of calculating a horizontal position of the center of gravity of the first group of articles composed of the plurality of articles as a first center of gravity position;
A function of selecting an article farthest from the first center of gravity position as the article to be taken out of the first article group;
A function of calculating a horizontal position of the center of gravity of the second group of articles made of articles included in an area centered on the article to be taken out of the first group of articles as a second center of gravity position;
A function of calculating a direction from the second gravity center position toward the horizontal position of the gravity center of the article to be taken out as a horizontal movement direction, and inputting the horizontal movement direction to the control unit;
A program to realize Recognize multiple items placed so as not to overlap each other, calculate the position and orientation,
The horizontal position of the center of gravity of the first group of articles composed of the plurality of articles is calculated as the first center of gravity position,
Selecting the article farthest from the first center of gravity position as the article to be taken out of the first article group;
The horizontal position of the center of gravity of the second article group consisting of articles included in the region centered on the article to be taken out of the first article group is calculated as the second center of gravity position,
A direction from the second center of gravity position toward the horizontal position of the center of gravity of the article to be taken out is calculated as a horizontal movement direction;
A robot control method, comprising: controlling an articulated robot so that an article to be taken out is moved by a predetermined movement amount in the horizontal movement direction and then taken out in a vertical direction.

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