Work holding system, work holding method, program, and control device

Abstract

To retain a workpiece at an appropriate retaining point.SOLUTION: A workpiece retention system comprises: retention means which retains a workpiece; information acquisition means which acquires three dimensional information of the workpiece; candidate calculation means which calculates, based on the three dimensional information of the workpiece acquired by the information acquisition means, a plurality of retention candidate points that are candidates of retention points of the workpiece when the retention means retains the workpiece; and control means controlling the retention means to retain the workpiece at selected retention candidate point in which normal line information of faces including respective retention candidate points is calculated based on the three dimensional information of the workpiece acquired by the information acquisition means, and at least one retention candidate point is selected from the plurality of retention candidate points based on the calculated normal line information of respective retention candidate points.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a work holding system, a work holding method, a program, and a control device for holding a work.

Background Art

[0002] A work holding system is known that determines a work holding point when a holding means holds a work based on three-dimensional information of the work. Although a technique for recognizing the orientation of a work based on the normal line information of the work is known (see, for example, Patent Document 1), it does not determine the holding point of the work.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when the three-dimensional information of the work contains noise, there is a risk that the noise is determined as the holding point and the work is held at the inappropriate holding point.

[0005] The present invention has been made to solve such problems, and a main object thereof is to provide a work holding system, a work holding method, a program, and a control device that can hold a work at an appropriate holding point.

Means for Solving the Problems

[0006] One aspect of the present invention for achieving the above object is a holding means for holding a work, an information acquisition means for acquiring three-dimensional information of the work, Candidate calculation means for calculating a plurality of holding candidate points that are candidates for the holding points of the workpiece when the holding means holds the workpiece based on the three-dimensional information of the workpiece acquired by the information acquisition means; Based on the three-dimensional information of the workpiece acquired by the information acquisition means, normal line information of the plane including each holding candidate point is calculated respectively, and based on the calculated normal line information of each holding candidate point, at least one holding candidate point is selected from the plurality of holding candidate points, and the holding means is controlled to hold the workpiece at the selected holding candidate point. Control means; Comprising Work holding system It is. In this aspect, the candidate calculation means detects a convex portion based on the three-dimensional information of the workpiece acquired by the information acquisition means, and calculates the holding candidate points based on the detected convex portion. The control means may select at least one holding candidate point from the plurality of holding candidate points based on the normal line information of each holding candidate point and the area of the end face of the convex portion of each holding candidate point. In this aspect, the control means may select a holding candidate point whose normal line information is equal to or greater than a first threshold value from among the plurality of holding candidate points, and then select a holding candidate point whose end face area of the convex portion is equal to or greater than a second threshold value from among the selected holding candidate points. In this aspect, the control means (1) After selecting a holding candidate point whose normal line information is equal to or greater than a third threshold value from among the plurality of holding candidate points calculated by the candidate calculation means, select a holding candidate point whose end face area of the convex portion is equal to or greater than a fourth threshold value from among the selected holding candidate points. (2) At the same time, after selecting a holding candidate point whose normal line information is equal to or greater than a fifth threshold value smaller than the third threshold value from among the plurality of holding candidate points calculated by the candidate calculation means, select a holding candidate point whose end face area of the convex portion is equal to or greater than a sixth threshold value larger than the fourth threshold value from among the selected holding candidate points. The holding means may be controlled to hold the workpiece at the holding candidate points selected in (1) and (2). One aspect of the present invention for achieving the above object is A step of acquiring three-dimensional information of a workpiece, Based on the acquired three-dimensional information of the workpiece, a step of calculating a plurality of holding candidate points that are candidates for holding points of the workpiece when the holding means holds the workpiece; Based on the acquired three-dimensional information of the workpiece, normal line information of the surfaces including the respective holding candidate points is calculated, and based on the normal line information of the respective calculated holding candidate points, at least one holding candidate point is selected from the plurality of holding candidate points, and the holding means is controlled to hold the workpiece at the selected holding candidate point; Including, Workpiece holding method It may be. One aspect of the present invention for achieving the above object is, A process of acquiring three-dimensional information of a workpiece, Based on the acquired three-dimensional information of the workpiece, a process of calculating a plurality of holding candidate points that are candidates for holding points of the workpiece when the holding means holds the workpiece; Based on the acquired three-dimensional information of the workpiece, normal line information of the surfaces including the respective holding candidate points is calculated, and based on the normal line information of the respective calculated holding candidate points, at least one holding candidate point is selected from the plurality of holding candidate points, and the holding means is controlled to hold the workpiece at the selected holding candidate point; To be executed by a computer, Program It may be. One aspect of the present invention for achieving the above object is, Candidate calculation means for calculating a plurality of holding candidate points that are candidates for holding points of the workpiece when the holding means holds the workpiece based on the three-dimensional information of the workpiece; Based on the three-dimensional information of the workpiece, normal line information of the surfaces including the respective holding candidate points is calculated, and based on the normal line information of the respective calculated holding candidate points, at least one holding candidate point is selected from the plurality of holding candidate points, and control means for controlling the holding means to hold the workpiece at the selected holding candidate point; Comprising, Control device It may be.

Advantages of the Invention

[0007] According to the present invention, it is possible to provide a work holding system, a work holding method, a program, and a control device that can hold a work at an appropriate holding point.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0009] Embodiment 1 Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing a schematic system configuration of a work holding system according to this embodiment. The work holding system 1 according to this embodiment can hold and move one work at a time from a plurality of works arranged in a three-dimensional space. The plurality of works are parts such as those stacked in a box or on a flat plate. Note that the plurality of works include parts of any shape such as a planar shape or a three-dimensional shape.

[0010] The work holding system 1 according to this embodiment includes a robot arm 2, a control device 3, and a three-dimensional vision sensor 4.

[0011] The robot arm 2 is a specific example of the holding means. The robot arm 2 is configured, for example, as a multi-joint arm having a plurality of links 21, joints (such as a wrist joint, an elbow joint, a shoulder joint, etc.) 23 that rotatably connect the respective links 21, and an end effector 24 provided at its tip for holding a workpiece.

[0012] Each joint 23 is provided with a rotation sensor such as an encoder that detects the rotation information of each joint 23, an actuator such as a servo motor that drives each joint 23, a force sensor that detects the operating force of each joint 23, and the like. The force sensor is, for example, a torque sensor that detects the torque of each joint 23. Each joint 23 is provided with a speed reduction mechanism or the like.

[0013] The end effector 24 attracts and holds the workpiece in a non-contact state by an attractive force such as a magnetic force or an air pressure. The end effector 24 is configured, for example, to electromagnetically adsorb the workpiece by generating a magnetic force and release the electromagnetically adsorbed workpiece by stopping the generation of the magnetic force. The end effector 24 may be configured to grip the workpiece with finger portions or the like.

[0014] A force sensor 5 may be provided between the link tip side of the robot arm 2 and the end effector 24. When the end effector 24 attracts and holds the workpiece, the weight of the workpiece acts on the end effector 24. The force sensor 5 detects the weight of the workpiece.

[0015] The control device 3 may determine whether or not the holding of the workpiece is successful based on the weight of the workpiece detected by the force sensor 5. The control device 3 may determine that the holding of the workpiece has failed based on the weight of the workpiece detected by the force sensor 5, for example, when the end effector 24 of the robot arm 2 attracts and holds a plurality of workpieces simultaneously or when it is determined that 0 workpieces are held.

[0016] The control device 3 performs various arithmetic processes and control processes on the robot arm 2. The control device 3 has, for example, a hardware configuration of a normal computer including a processor 3a such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), an internal memory 3b such as a RAM (Random Access Memory) or a ROM (Read Only Memory), a storage device 3c such as an HDD (Hard Disk Drive) or an SDD (Solid State Drive), an input / output I / F 3d for connecting peripheral devices such as a display, and a communication I / F 3e for communicating with devices outside the apparatus.

[0017] The three-dimensional vision sensor 4 is a specific example of the information acquisition means. The three-dimensional vision sensor 4 acquires three-dimensional information of a plurality of workpieces. The three-dimensional information of the workpiece includes information such as the shape, position, and posture of each workpiece.

[0018] The three-dimensional vision sensor 4 is provided, for example, at the end effector 24 or the link 21 of the robot arm 2, or at a position above or to the side of a workpiece other than the robot arm 2. The three-dimensional vision sensor 4 is composed of a camera, a laser sensor, or the like. The three-dimensional vision sensor 4 outputs the acquired three-dimensional information of the workpiece to the control device 3.

[0019] FIG. 2 is a block diagram showing a schematic system configuration of the control device according to the present embodiment. The control device 3 according to the present embodiment has a candidate calculation unit 31 and a robot control unit 32.

[0020] The candidate calculation unit 31 is a specific example of the candidate calculation means. The candidate calculation unit 31 calculates a plurality of holding candidate points, which are candidates for the holding points (adsorption points) of the workpiece when the end effector 24 of the robot arm 2 holds the workpiece, based on the three-dimensional information of the workpiece acquired by the three-dimensional vision sensor 4.

[0021] FIG. 3 is a flowchart showing the flow of the method for calculating holding candidate points according to the present embodiment. The three-dimensional vision sensor 4 acquires three-dimensional information of a plurality of workpieces (step S101). The candidate calculation unit 31 calculates depth information indicating the height position of each workpiece based on the three-dimensional information of the workpiece acquired by the three-dimensional vision sensor 4 (step S102).

[0022] The candidate calculation unit 31 detects the convex portions of each workpiece based on the calculated depth information of each workpiece (step S103). The candidate calculation unit 31 may perform binarization with points equal to or higher than a predetermined height set to 1 and points lower than the predetermined height set to 0, and detect the points that become 1 as convex portions. Further, the candidate calculation unit 31 may detect, from among the detected convex portions, convex portions having an end face area for the end effector 24 to perform suction equal to or greater than a threshold value as holding candidate points (step S104).

[0023] The candidate calculation unit 31 outputs the plurality of holding candidate points calculated as described above to the robot control unit 32.

[0024] The robot control unit 32 is a specific example of a control means. The robot control unit 32 controls the operation of the robot arm 2. The robot control unit 32 controls the actuators of the respective joint portions 23 based on, for example, rotation information (such as a rotation angle) from the rotation sensors of the respective joint portions 23 and the operating force from the force sensors, thereby performing feedback control on the robot arm 2. Further, the robot control unit 32 controls the suction and release of the workpiece by the end effector 24. Thereby, the robot control unit 32 can hold and move the workpiece by controlling the robot arm 2.

[0025] The robot control unit 32 selects at least one holding candidate point from among the plurality of holding candidate points calculated by the candidate calculation unit 31.

[0026] By the way, conventionally, when the three-dimensional information of a workpiece acquired by a three-dimensional vision sensor contains noise, the noise is determined as a holding point, and there is a risk that the workpiece may be held at the inappropriate holding point. Note that noise is, for example, a phenomenon in which data having a certain size appears in a portion where there is originally nothing on an image.

[0027] On the other hand, in the present embodiment, the robot control unit 32 calculates the normal information of each surface including each holding candidate point based on the three-dimensional information of the workpiece acquired by the three-dimensional vision sensor 4. Based on the calculated normal information of each holding candidate point, the robot control unit 32 selects at least one holding candidate point from among the plurality of holding candidate points, and controls the robot arm to hold the workpiece at the selected holding candidate point.

[0028] When the three-dimensional information of the workpiece acquired by the three-dimensional vision sensor 4 contains noise, the surface including the noise is likely to be inclined, and the inclination of the surface appears in the normal information of the surface. By utilizing such characteristics of the noise, the robot control unit 32 can select an appropriate holding candidate point by removing the holding candidate point that is noise from among the plurality of holding candidate points based on the calculated normal information of each holding candidate point, and can hold the workpiece at the appropriate holding candidate point.

[0029] The robot control unit 32 calculates normal vector values as the normal information of each surface including each holding candidate point based on the three-dimensional information of the workpiece acquired by the three-dimensional vision sensor 4. The robot control unit 32 calculates, for example, the normal vector value of each surface including each holding candidate point using the PCL (Point Cloud Library) normal estimation method, but is not limited thereto. The robot control unit 32 may calculate the normal vector value of each surface including each holding candidate point using any calculation method.

[0030] The robot control unit 32 selects at least one holding candidate point from among the plurality of holding candidate points based on the calculated normal vector values of the respective holding candidate points. For example, when a holding candidate point is noise, the normal vector value of the plane including the holding candidate point becomes a small value. Therefore, the robot control unit 32 selects at least one holding candidate point whose calculated normal vector value is equal to or greater than the first threshold value. For example, the normal vector value when the holding candidate point is not noise is experimentally obtained and set in the robot control unit 32 as the first threshold value.

[0031] Based on the three-dimensional information of the workpiece acquired by the three-dimensional vision sensor 4, the robot control unit 32 controls the robot arm 2 so that the end effector 24 of the robot arm 2 holds the workpiece at the selected holding candidate point.

[0032] Subsequently, the workpiece holding method according to the present embodiment will be described. FIG. 4 is a flowchart showing the flow of the workpiece holding method according to the present embodiment. Note that the control process shown in FIG. 4 is repeatedly executed every predetermined time.

[0033] The three-dimensional vision sensor 4 acquires three-dimensional information of the workpiece and outputs it to the control device 3 (step S201).

[0034] Based on the three-dimensional information of the workpiece acquired by the three-dimensional vision sensor 4, the candidate calculation unit 31 of the control device 3 calculates a plurality of holding candidate points of the end effector 24 of the robot hand (step S202).

[0035] Based on the three-dimensional information of the workpiece acquired by the three-dimensional vision sensor 4, the robot control unit 32 of the control device 3 calculates the normal vector value of the plane including each holding candidate point (step S203).

[0036] Based on the calculated normal vector values of the respective holding candidate points, the robot control unit 32 selects at least one holding candidate point from among the plurality of holding candidate points (step S204).

[0037] Based on the three-dimensional information of the workpiece acquired by the three-dimensional vision sensor 4, the robot control unit 32 controls the robot arm 2 so that the end effector 24 of the robot arm 2 holds the workpiece at the holding candidate point (step S205).

[0038] As described above, in the present embodiment, the robot control unit 32 calculates the normal line information of each surface including each holding candidate point based on the three-dimensional information of the workpiece acquired by the three-dimensional vision sensor 4. Based on the calculated normal line information of each holding candidate point, the robot control unit 32 selects at least one holding candidate point from among the plurality of holding candidate points, and controls the robot arm 2 to hold the workpiece at the selected holding candidate point.

[0039] Thereby, based on the calculated normal line information of each holding candidate point, the robot control unit 32 can remove the holding candidate points that are noise from among the plurality of holding candidate points, select an appropriate holding candidate point, and hold the workpiece at the appropriate holding point.

[0040] Embodiment 2 In the present embodiment, the robot control unit 32 selects at least one holding candidate point from among the plurality of holding candidate points based on the normal vector value of each holding candidate point and the area of the end face of the convex portion of each holding candidate point. Thereby, using the normal vector value of the holding candidate point and the area of the end face of the convex portion of the holding candidate point, noise can be more reliably removed.

[0041] As described above, when the holding candidate point is noise, the normal vector value of the surface including the holding candidate point becomes a small value. Further, when the holding candidate point is noise, the area of the end face of the convex portion of the holding candidate point also becomes a small value.

[0042] Therefore, after the robot control unit 32 selects a holding candidate point having a normal vector value greater than or equal to the first threshold value from among a plurality of holding candidate points, the robot control unit 32 may select a holding candidate point having a convex end face area greater than or equal to the second threshold value from among the selected holding candidate points. For example, the area of the convex end face when the holding candidate point is not noise is experimentally obtained and set in the robot control unit 32 as the second threshold value.

[0043] FIG. 5 is a flowchart showing the flow of the workpiece holding method according to the present embodiment. Note that the control process shown in FIG. 5 is repeatedly executed every predetermined time.

[0044] The three-dimensional vision sensor 4 acquires three-dimensional information of the workpiece and outputs it to the control device 3 (step S301).

[0045] Based on the three-dimensional information of the workpiece acquired by the three-dimensional vision sensor 4, the candidate calculation unit 31 of the control device 3 calculates a plurality of holding candidate points of the end effector 24 of the robot hand (step S302).

[0046] Based on the three-dimensional information of the workpiece acquired by the three-dimensional vision sensor 4, the robot control unit 32 of the control device 3 calculates the normal vector values of the planes including the respective holding candidate points (step S303).

[0047] The robot control unit 32 selects a holding candidate point having a normal vector value greater than or equal to the first threshold value from among the plurality of holding candidate points calculated by the candidate calculation unit 31 (step S304).

[0048] The robot control unit 32 calculates the areas of the convex end faces of the respective selected holding candidate points (step S305).

[0049] The robot control unit 32 selects a holding candidate point having a convex end face area greater than or equal to the second threshold value from among the selected holding candidate points (step S306).

[0050] Based on the three-dimensional information of the workpiece acquired by the three-dimensional vision sensor 4, when the end effector of the robot arm 2 holds the workpiece at the holding candidate point selected, the robot control unit 32 determines whether the workpiece at the holding candidate point interferes with other workpieces and whether the end effector 24 can hold the workpiece at the holding candidate point (step S307).

[0051] When it is determined that the workpiece can be held at the holding candidate point, the robot control unit 32 controls the robot arm 2 to hold the workpiece at the holding candidate point (step S308).

[0052] In the above processing flow, the robot control unit 32 may select a holding candidate point whose end face area of the convex portion is equal to or greater than the second threshold from among a plurality of holding candidate points, and then select a holding candidate point whose normal vector value is equal to or greater than the first threshold from among the selected holding candidate points. As described above, it is more preferable for the robot control unit 32 to select a holding candidate point whose end face area of the convex portion is equal to or greater than the second threshold from among the selected holding candidate points after selecting a holding candidate point whose normal vector value is equal to or greater than the first threshold from among a plurality of holding candidate points, because the calculation time can be shortened.

[0053] Embodiment 3 In the above Embodiment 2, noise can be more reliably removed. On the other hand, there is a possibility that the holding candidate points are overly narrowed down. In contrast, in this embodiment, the threshold of the normal vector value and the threshold of the end face area of the convex portion for removing noise are adjusted. Thereby, while removing noise, it is possible to narrow down to an appropriate number of holding candidate points.

[0054] Noise has, for example, the characteristic that the normal vector value of the surface including the holding candidate point is a small value and the end face area of the convex portion of the holding candidate point is a small value. Therefore, it is preferable for the robot control unit 32 to select holding candidate points using, for example, thresholds set as follows.

[0055] (1) The robot control unit 32 selects holding candidate points whose normal vector values are equal to or greater than the third threshold value α3 from among the plurality of holding candidate points calculated by the candidate calculation unit 31, and then selects holding candidate points whose convex end face area is greater than the fourth threshold value α4 from among the selected holding candidate points. A large value may be set for the third threshold value α3 of the normal vector value, and a small value may be set for the fourth threshold value α4 of the area. Thereby, holding candidate points having a small area facing the direction of the three-dimensional vision sensor 4 can be extracted.

[0056] (2) Simultaneously with (1) above, the robot control unit 32 selects holding candidate points whose normal vector values are equal to or greater than the fifth threshold value α5 from among the plurality of holding candidate points calculated by the candidate calculation unit 31, and then selects holding candidate points whose convex end face area is greater than or equal to the sixth threshold value α6 from among the selected holding candidate points. A small value may be set for the fifth threshold value α5 of the normal vector value, and a large value may be set for the sixth threshold value α6 of the area. Note that the third threshold value α3 > the fifth threshold value α5, and the fourth threshold value α4 < the sixth threshold value α6. Thereby, holding candidate points having a large area with a small restriction on the surface including the holding candidate points can be extracted.

[0057] The robot control unit 32 controls the robot arm 2 to hold the workpiece at the holding candidate points selected by (1) and (2) above.

[0058] In addition, (3) the robot control unit 32 may select, simultaneously with (1) and (2) above, holding candidate points whose normal vector values are equal to or greater than the seventh threshold value α7 from among the plurality of holding candidate points calculated by the candidate calculation unit 31, and then select holding candidate points whose convex end face area is greater than or equal to the eighth threshold value α8 from among the selected holding candidate points. A small value may be set for the seventh threshold value α7 of the normal vector value, and a small value may be set for the eighth threshold value α8 of the area.

[0059] The robot control unit 32 may control the robot arm 2 to hold the workpiece at the holding candidate points selected by (1), (2), and (3) above.

[0060] Furthermore, (4) the robot control unit 32 may, simultaneously with (1), (2), and (3) above, select holding candidate points with a normal vector value of 9th threshold α9 or more from among the plurality of holding candidate points calculated by the candidate calculation unit 31, and then select holding candidate points with an area of the end face of the convex portion of 10th threshold α10 or more from among the selected holding candidate points. Values between the above thresholds may be set for the 9th threshold α9 of the normal vector value and the 10th threshold α10 of the area.

[0061] Although some embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalent scope thereof.

[0062] The present invention can also be realized, for example, by causing a processor to execute a computer program for the processes shown in FIGS. 3 to 5.

[0063] The program can be stored using various types of non-transitory computer readable media and supplied to a computer. Non-transitory computer readable media include various types of tangible storage media. Examples of non-transitory computer readable media include magnetic recording media (e.g., flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (e.g., magneto-optical disks), CD-ROM (Read Only Memory), CD-R, CD-R / W, semiconductor memories (e.g., mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM (random access memory)).

[0064] The program may be supplied to a computer by various types of transitory computer readable media. Examples of transitory computer readable media include electrical signals, optical signals, and electromagnetic waves. The transitory computer readable media can supply the program to the computer via wired communication paths such as electric wires and optical fibers, or wireless communication paths.

[0065] Each part constituting the control unit according to each of the above-described embodiments can be realized not only by a program but also by dedicated hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array) for a part or all of them.

Description of Reference Numerals

[0066] 1 Workholding system, 2 Robot arm, 3 Control device, 3a Processor, 3b Internal memory, 3c Storage device, 4 3D vision sensor, 5 Force sensor, 21 Link, 23 Joint part, 24 End effector, 31 Candidate calculation unit, 32 Robot control unit

Claims

1. holding means for holding a workpiece; information acquisition means for acquiring three-dimensional information of the workpiece; candidate calculation means for calculating a plurality of holding candidate points which are candidates for holding points of the workpiece when the holding means holds the workpiece based on the three-dimensional information of the workpiece acquired by the information acquisition means; control means for calculating normal line information of a plane including each of the holding candidate points based on the three-dimensional information of the workpiece acquired by the information acquisition means, selecting at least one holding candidate point from the plurality of holding candidate points based on the calculated normal line information of each holding candidate point, and controlling the holding means to hold the workpiece at the selected holding candidate point; comprising: the candidate calculation means detects a convex portion based on the three-dimensional information of the workpiece acquired by the information acquisition means, and calculates the holding candidate points based on the detected convex portion; the control means selects a holding candidate point whose normal line information is equal to or greater than a first threshold value from among the plurality of holding candidate points, and then selects a holding candidate point whose end face area of the convex portion is equal to or greater than a second threshold value from among the selected holding candidate points; a workpiece holding system.

2. The workpiece holding system according to Claim 1, wherein the control means (1) selects a holding candidate point whose normal line information is equal to or greater than a third threshold value from among the plurality of holding candidate points calculated by the candidate calculation means, and then selects a holding candidate point whose end face area of the convex portion is greater than a fourth threshold value from among the selected holding candidate points; (2) simultaneously, selects a holding candidate point whose normal line information is equal to or greater than a fifth threshold value smaller than the third threshold value from among the plurality of holding candidate points calculated by the candidate calculation means, and then selects a holding candidate point whose end face area of the convex portion is equal to or greater than a sixth threshold value greater than the fourth threshold value from among the selected holding candidate points; controls the holding means to hold the workpiece at the holding candidate points selected in (1) and (2). a workpiece holding system.

3. A step in which the information acquisition means acquires three-dimensional information of a workpiece; a step in which the candidate calculation means calculates a plurality of holding candidate points which are candidates for holding points of the workpiece when the holding means holds the workpiece based on the acquired three-dimensional information of the workpiece; The control means calculates the normal line information of each surface including the respective holding candidate points based on the acquired three-dimensional information of the workpiece, and based on the calculated normal line information of each holding candidate point, selects at least one holding candidate point from among the plurality of holding candidate points, and controls the holding means to hold the workpiece at the selected holding candidate point; including The candidate calculation means detects a convex portion based on the three-dimensional information of the workpiece acquired by the information acquisition means, and calculates the holding candidate points based on the detected convex portion. After the control means selects a holding candidate point whose normal line information is equal to or greater than a first threshold value from among the plurality of holding candidate points, the control means selects a holding candidate point whose end face area of the convex portion is equal to or greater than a second threshold value from among the selected holding candidate points. Workpiece holding method.

4. A process of acquiring three-dimensional information of a workpiece, A process of calculating a plurality of holding candidate points which are candidates for holding points of the workpiece when the holding means holds the workpiece based on the acquired three-dimensional information of the workpiece, Based on the acquired three-dimensional information of the workpiece, calculating the normal line information of each surface including the respective holding candidate points, and based on the calculated normal line information of each holding candidate point, selecting at least one holding candidate point from among the plurality of holding candidate points, and controlling the holding means to hold the workpiece at the selected holding candidate point; A process of detecting a convex portion based on the acquired three-dimensional information of the workpiece, and calculating the holding candidate points based on the detected convex portion. A process of selecting a holding candidate point whose normal line information is equal to or greater than a first threshold value from among the plurality of holding candidate points, and then selecting a holding candidate point whose end face area of the convex portion is equal to or greater than a second threshold value from among the selected holding candidate points. Causing a computer to execute Program.

5. Candidate calculation means for calculating a plurality of holding candidate points which are candidates for holding points of the workpiece when the holding means holds the workpiece based on the three-dimensional information of the workpiece, Based on the three-dimensional information of the workpiece, calculating the normal line information of each surface including the respective holding candidate points, and based on the calculated normal line information of each holding candidate point, selecting at least one holding candidate point from among the plurality of holding candidate points, and controlling the holding means to hold the workpiece at the selected holding candidate point; comprising The candidate calculation means detects a convex portion based on the three-dimensional information of the workpiece, and calculates the holding candidate points based on the detected convex portion. After the control means selects a holding candidate point whose normal line information is equal to or greater than a first threshold from among the plurality of holding candidate points, the control means selects a holding candidate point whose convex end face area is equal to or greater than a second threshold from among the selected holding candidate points. Control device.

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