Robot hand, method for controlling a robot hand, robot system, method for manufacturing an article using a robot system, control program, and recording medium.

Abstract

This reduces the possibility of interference between the part holder and the object that the part comes into contact with. [Solution] A robot hand capable of holding a workpiece is employed, comprising a first member for holding the workpiece and a second member that can contact the workpiece while the workpiece is held by the first member, wherein the posture of the workpiece is changed by displacing the first member or the second member while the workpiece is held by the first member.

Description

Technical Field

[0001] The present invention relates to a robot hand.

Background Art

[0002] When a robot hand holds or assembles parts, it is required that the posture of the parts held by the robot hand changes little while being held. If the posture of the held parts is unstable during holding or assembly, the held parts may interfere with other structures or mounting parts, or may interfere with the assembly target and prevent assembly. In order to reduce the change in the posture of the parts held by the robot hand, it is necessary to resist the load and moment of the held parts. Therefore, many robot hands have a large holding force and high rigidity, or the robot hand is enlarged to hold near both ends of the long side of the parts, and the hand size may become significantly larger compared to the size and weight of the parts. As a robot hand technology for stabilizing the part posture and handling in a form of holding near both ends of the long side of the part, for example, Patent Document 1 below is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The robot hand described in Patent Document 1 has a gripping part for grasping a part, and an auxiliary part that can move in a direction toward the part from the palm of the robot hand and in a direction perpendicular to that direction. The gripping part grasps the workpiece near its center of gravity, and the auxiliary part holds both ends of the long side of the workpiece. However, the gripping part grasps the workpiece near its center of gravity. Therefore, for example, in an operation such as inserting a long part into a part to be assembled from one end of the long part and assembling it to the vicinity of the other end, the holding part may interfere with the part to be assembled, making it impossible to perform certain assembly operations.

[0005] This invention maintains the orientation of a component even when the holding position for the component is predetermined. [Means for solving the problem]

[0006] The present invention employs a robot hand capable of holding a workpiece, comprising a first member for holding the workpiece and a second member capable of contacting the workpiece while the workpiece is held by the first member, wherein the posture of the workpiece is changed by displacing the first member or the second member while the workpiece is held by the first member. [Effects of the Invention]

[0007] According to the present invention, the orientation of a component can be maintained even when the holding position for the component is predetermined. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram of the robot system 1000 in an embodiment. [Figure 2] This is a schematic diagram of the robot hand 40 in the embodiment. [Figure 3] This is a schematic diagram illustrating the change in the orientation of the workpiece 11 in the embodiment. [Figure 4] This is a schematic diagram illustrating the change in the orientation of the workpiece 11 in the embodiment. [Figure 5] This is a control flowchart in the embodiment. [Figure 6] This is a schematic diagram of the robot system 1000 in an embodiment. [Figure 7] This is a schematic diagram of the robot hand 40 in the embodiment. [Figure 8] This is a schematic diagram illustrating the change in the orientation of the workpiece 11 in the embodiment. [Figure 9] This is a schematic diagram of the robot hand 40 in the embodiment. [Figure 10] This is a schematic diagram of the robot hand 40 in the embodiment. [Figure 11] This is a schematic diagram of the robot hand 40 in the embodiment. [Figure 12] This is a schematic diagram of the robot system 1000 in an embodiment. [Figure 13] This is a schematic diagram illustrating the change in the orientation of the workpiece 11 in the embodiment. [Figure 14] This is a control flowchart in the embodiment. [Figure 15] This is a control flowchart in the embodiment. [Modes for carrying out the invention]

[0009] The embodiments for carrying out the present invention will be described below with reference to the examples shown in the attached drawings. Note that the embodiments described below are merely examples, and for example, the detailed configuration can be appropriately modified by those skilled in the art without departing from the spirit of the present invention. Furthermore, the numerical values ​​discussed in these embodiments are for reference only and do not limit the present invention. In the following drawings, the arrows X, Y, and Z indicate the overall coordinate system of the robot system. Generally, the XYZ three-dimensional coordinate system represents the world coordinate system of the entire installation environment. In addition, a local coordinate system may be used for the robot hand, fingers, joints, etc., depending on control considerations. Furthermore, in describing the robot hand according to this embodiment, an embodiment of the robot hand in a parts holding device that performs parts picking, transferring, and assembly will be used as an example. However, the use of the robot hand according to this embodiment is not limited to a parts holding device.

[0010] (First Embodiment) Figure 1 is a schematic diagram showing a robot system 1000 according to this embodiment. The robot system 1000 takes out multiple workpieces 11 that are arranged in a box 10 and transfers them to a box 12. Multiple boxes 10 may be provided for each type of workpiece 11, and they may be replaced by a conveyor or AGV (Automatic Guided Vehicle). Furthermore, by providing partitions in the box 12 and changing the position where each type of workpiece 11 is placed, it can be used as a device to collect the workpieces necessary for assembling a product. The box 12 shown in Figure 1 is a box with a mold for the workpiece 11, and it is assumed that the holding member 42 will interfere with the box 12 unless the ends of the workpiece 11 are held. In addition to placing the workpieces 11 in the box 12, the workpieces 11 may also be transferred to a device that performs assembly, or the workpieces 11 may be brought into direct contact with another workpiece and assembled. In this way, the manufacturing of goods may be carried out by moving the workpieces 11 and assembling them by bringing them into contact with the workpiece to be assembled.

[0011] The robot arm 31 is a manipulator and includes a robot hand 40 as an end effector. The robot arm 31 shown in FIG. 1 is a vertically articulated robot arm. The robot hand 40 is supported by the robot arm 31. The robot hand 40 is attached to a predetermined part of the robot arm 31, for example, the tip of the robot arm 31. The robot hand 40 is configured to be able to hold the workpiece 11.

[0012] Each joint of the robot arm 31 and the finger part (holding part) of the robot hand 40 are respectively provided with a motor as a drive source for driving them, a reducer, and an encoder as position detection means for detecting the rotation angle of the motor. Note that the installation position and output method of the encoder are not limited. Based on the values from these encoders, control commands for each motor are output. Then, by driving each motor, the robot arm 31 can be set in various poses, the robot hand 40 can be positioned at various positions and poses, and by driving the finger part, operations on the workpiece 11 can be executed. In addition, sensors capable of detecting force information may be provided at each joint of the robot arm 31 and the finger part (holding part) of the robot hand 40.

[0013] The system control device 20 sends commands to the robot arm 31, the robot hand 40, and other devices to control the entire system. The system control device 20 is composed of a computer including a microprocessor or the like. The computer constituting the system control device 20 has a CPU (Central Processing Unit) 20a as shown in FIG. 1. Further, it has a ROM (Read Only Memory) 20b and a RAM (Random Access Memory) 20c. Further, it includes a communication interface (hereinafter referred to as "I / F") 20d and the like. These can communicate with each other by bus communication. The CPU 20a, which is a processor, is an example of a control unit.

[0014] The program 20e is recorded in the ROM 20b. The program 20e is a program for causing a computer, that is, the CPU 20a, to output instructions for controlling the robot arm 31, the robot hand 40, and other devices. The RAM 20c is used to temporarily store programs for executing the control of the entire system, data such as the execution timing of operations and control commands for each control target. The CPU 20a acquires data transmitted from, for example, the input device 21, the robot control device 30, the image processing device 50, and various sensors described later, by receiving it through the I / F 20d. Also, the CPU 20a can transmit commands as control target values to a control device that controls each control target, via the I / F 20d, based on programs and data input by the user. In the present embodiment, a plurality of control devices such as the robot control device 30 and the image processing device 50 are used, but it is not limited thereto. For example, only the system control device 20 may execute the control of the robot arm 31 and the robot hand 40, and the acquisition of data from the imaging device 52 described later. That is, the control of the system may be executed by at least one control device. In the present embodiment, the communication between the system control device 20, the robot control device 30, and the image processing device 50 is assumed to be executed by wired communication, but it may be executed by wireless communication.

[0015] In the present embodiment, the program 20e is recorded in the ROM 20b, but it is not limited thereto. The program 20e may be recorded in any recording medium as long as it is a non-temporary recording medium readable by a computer. As a recording medium for supplying the program 20e to a computer, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a magnetic tape, a non-volatile memory, etc. can be used.

[0016] For the sake of simplicity, the illustration in Figure 1 is omitted, but the robot control device 30 and image processing device 50, like the system control device 20, are composed of computers including a microprocessor. The robot control device 30 and image processing device 50 have a CPU, ROM, and RAM. They are also composed of a communication interface (hereinafter referred to as "I / F") and the like. Each CPU, which is a processor, is an example of a control unit.

[0017] The robot arm 31 and robot hand 40 are operated by the robot control device 30 based on commands from the system control device 20. The robot control device 30 is connected to the system control device 20 so as to be able to communicate with it by wire or wireless, and in response to a command from the system control device 20, it starts picking and placing the workpiece 11 and transmits a message to the system control device 20 when the pick and place operation is completed.

[0018] The robot control device 30 is connected to each drive unit of the robot arm 31 so as to be able to communicate with them, and controls the movement of the robot arm 31 in real time. The CPU of the robot control device 30 executes the program recorded in the ROM, which enables the execution of the aforementioned movements of the robot arm 31. Furthermore, the ROM of the image processing device 50 can store trajectory data consisting of the angle values ​​of each joint, which is necessary for the movement of the robot arm 31.

[0019] Furthermore, the robot control device 30 is connected to each drive unit of the robot hand 40 so as to be able to communicate with it, and controls the movement of the fingers (holding parts) mounted on the robot hand 40 in real time. By moving the fingers closer together or further apart from each other, the fingers can come into contact with the workpiece 11, making it possible to grip (hold) the workpiece 11. The movement of the fingers closer together or further apart can be driven by a motor or compressed air.

[0020] When driven by a motor, numerical control is used; when driven by compressed air, speed is controlled, and it is desirable to set the gripping force, speed, and stroke according to the characteristics of the workpiece 11. For example, if the workpiece 11 is heavy, the gripping force should be increased to prevent it from being dropped during transport by the robot arm 31 and robot hand 40. Also, if the workpiece 11 is soft, the holding force should be decreased to prevent deformation of the workpiece 11. The CPU of the robot control device 30 executes the program recorded in the ROM, enabling the control of each finger as described above. Furthermore, the ROM of the robot control device 30 can store data consisting of numerical values ​​and speed information necessary for the operation of the fingers.

[0021] The image processing device 50 is connected to at least one imaging device 52 via wired or wireless communication and controls each imaging device 52 and processes the captured images. In this embodiment, each imaging device consists of a camera and a lens, but illumination may be provided as needed. The image processing performed by the image processing device 50 includes acquiring information about the posture of the workpiece 11 held by the robot hand 40 through processing, compositing, and matching of two-dimensional images. The image processing device 50 acquires the posture of the workpiece 11 grasped by the robot hand 40 based on a command from the system control device 20 and transmits the acquired posture information to the system control device 20. The CPU of the image processing device 50 executes the above-mentioned image processing by running a program recorded in the ROM. Furthermore, the ROM of the image processing device 50 can store various parameters necessary for image processing. The system control device 20 then transmits data to the robot control device 30 for controlling the robot hand 40 based on the acquired posture information of the workpiece 11. This enables tilt correction of the workpiece 11 by the robot hand 40 and position correction of the workpiece 11 by the robot arm 31. In the example shown in Figure 1, two imaging devices are provided: one that images the workpiece 11 from the X direction and another that images the workpiece 11 from the Z direction. However, as long as the orientation of the workpiece 11 can be detected, one imaging device is sufficient, or there may be three or more.

[0022] An input device 21 is connected to the system control device 20 for the user to input commands. A teaching pendant is preferred as the input device 21, but various terminals such as smartphones and tablets may be used. The input device 21 shown in Figure 1 is explained using a tablet-type teaching pendant equipped with a touch panel display as a user interface as an example. The touch panel display of the input device 21 shown in Figure 1 displays buttons such as "Fully Automatic," "Automatic," "Manual," "Origin," "Start," and "Adjust." By pressing these buttons, the user can execute commands to the system control device 20 for the robot arm 31 and / or robot hand 40.

[0023] Figure 2 is a schematic diagram showing a robot hand 40 according to this embodiment. As shown in Figure 2, the robot hand 40 has a palm portion 41, a holding member 42 that operates to grip a workpiece 11, and a contact member 43 that can contact the workpiece 11 when the workpiece 11 is gripped by the holding member 42. The holding member 42 may be referred to as the first member, and the contact member 43 as the second member. As shown in Figure 2, when holding the workpiece 11 near an edge offset from its center of gravity, if the holding force that can be output by the holding member 42 is insufficient to withstand the change in the posture of the workpiece 11 due to its own weight, the workpiece 11 will tilt in the direction of gravity due to its own weight, and the posture of the workpiece 11 will change. Therefore, in this embodiment, the robot hand 40 is designed so that the relative position between the holding member 42 and the contact member 43 can be displaced while the workpiece 11 is being held by the holding member 42. From Figure 2, with the Y direction as the reference, when the workpiece 11 is held by the holding member 42, the holding member 42 is positioned between the center of gravity of the workpiece 11 and the contact member 43.

[0024] Figure 3 is a schematic diagram showing the operation of the robot hand 40 in this embodiment to change the posture of the workpiece 11. Figure 3(a) is a perspective view, and Figure 3(b) is a side view thereof. From Figures 3(a) and (b), the contact member 43 is fixed to the palm portion 41, and the holding member 42 further has the function of being displaced relative to the palm portion 41 in a direction toward or toward the contact member 43. With the workpiece 11 held by the holding member 42, by moving the holding member 42 toward the contact member 43, it becomes possible to displace the posture of the workpiece 11 with the contact point between the contact member 43 and the workpiece 11 as the pivot point, thereby correcting the posture of the workpiece 11. More specifically, by moving the holding member 42 in the opposite direction to the direction of gravity of the workpiece 11, the posture of the workpiece 11 is displaced. In addition, by holding the end of the workpiece 11 away from the center of gravity with the holding member 42, a certain degree of reproducibility is given to the tilt of the posture of the workpiece 11. Furthermore, the position of the contact member 43 is set to be on the opposite side from the side in which the posture of the workpiece 11 is tilted.

[0025] Furthermore, as shown in Figure 4, the contact member 43 may be brought closer to the holding member 42. Figure 4 is a schematic diagram showing a modified example of the operation for changing the posture of the workpiece 11 by the robot hand 40 in this embodiment. In Figure 4, the holding member 42 is fixed to the palm portion 41 so as not to be able to approach the contact member 43, and has the function of bringing the contact member 43 closer to the holding member 42. With the workpiece 11 held by the holding member 42, by bringing the contact member 43 closer to the holding member 42, it becomes possible to displace the posture of the workpiece 11 using the contact point between the contact member 43 and the workpiece 11 as a pivot point, thereby correcting the posture of the workpiece 11. To elaborate further, the posture of the workpiece 11 is displaced by moving the contact member 43 in the direction of gravity of the workpiece 11. In the example of Figures 3 and 4, the function is provided to bring either the holding member 42 or the contact member 43 closer, but it is also possible to provide the function to bring both the holding member 42 and the contact member 43 closer. In short, it is sufficient to bring either the holding member 42 or the contact member 43 closer to the other.

[0026] Figure 5 is a flowchart of the operations performed on the workpiece 11 in this embodiment. The control flow shown in Figure 5 is executed through communication between the CPUs of each control device.

[0027] As shown in Figure 5, in step S11, the system control device 20 first sends a command to the robot control device 30, and the robot control device 30 operates the robot arm 31 to move the robot hand 40 to the top of the box 10. Before operating the robot hand 40, it is desirable to acquire the posture of the robot arm 31 and to move it by providing intermediate points as needed to avoid interference with the box 12 and box 10.

[0028] Next, in step S12, the robot control device 30 moves to a position to hold the workpiece 11 placed in the box 10. It is assumed that there are multiple places to place workpieces 11 inside the box 10. The robot arm 31 should have as many teaching points for holding positions as there are places to place workpieces 11, and it is desirable to provide appropriate intermediate points so that the robot hand 40 does not interfere with the box 10 or other workpieces 11 when moving from the upper position of the box 10 to the holding position.

[0029] Next, in step S13, the robot control device 30 moves the holding member 42 of the robot hand 40 in the direction of holding the workpiece 11 to hold the workpiece 11.

[0030] Next, in step S14, the robot control device 30 uses the robot arm 31 to move the robot hand 40 and the workpiece 11 to a position where the posture of the workpiece 11 held by the robot hand 40 can be recognized by the imaging device 52. After moving the workpiece 11, the robot control device 30 transmits information to the system control device 20 indicating that the movement of the workpiece 11 is complete.

[0031] Next, in step S15, after the system control device 20 receives information indicating that the movement of the workpiece 11 is complete, it sends a command to the image processing device 50 to perform recognition of the workpiece 11. The image processing device 50 acquires information regarding the orientation of the workpiece 11 obtained from the imaging device 52.

[0032] Then, in step S16, a correction amount for the posture of the workpiece 11 is obtained based on a reference image showing the posture of the target workpiece 11 and an acquired image showing the current posture of the workpiece 11 obtained in step S15. The correction amount is obtained as the amount of movement of the holding member 42 or the contact member 43. Then, the information obtained regarding the amount of movement of the holding member 42 or the contact member 43 is transmitted to the system control device 20.

[0033] Next, in step S17, the system control device 20 transmits the amount of movement transmitted from the image processing device 50 to the robot control device 30, and also transmits a command to change the posture of the workpiece 11 to the robot control device 30. Based on the amount of movement transmitted from the system control device 20, the robot control device 30 moves the holding member 42 and / or the contact member 43, bringing the holding member 42 and / or the contact member 43 into contact with the workpiece 11 to change and correct the posture of the workpiece 11. The robot control device 30 then transmits information to the system control device 20 indicating that the movement of the holding member 42 and / or the contact member 43 has been completed.

[0034] Next, in step S18, after the system control device 20 receives information indicating that the holding member 42 and / or contact member 43 have completed moving, it sends a command to the image processing device 50 to perform recognition of the workpiece 11. The image processing device 50 acquires information regarding the orientation of the workpiece 11 obtained from the imaging device 52.

[0035] Next, in step S19, the image processing device 50 determines whether the posture of the workpiece 11 is the target posture based on the reference image showing the posture of the target workpiece 11 and the acquired image showing the current posture of the workpiece 11 acquired in step S18. In the determination, an acceptable range is set for the difference between the current posture and the target posture of the workpiece 11. If the difference between the current posture and the target posture of the workpiece 11 is not within the acceptable range, step S19: No is performed, and the device returns to just before step S16 to acquire the amount of movement of the holding member 42 and / or contact member 43 to correct the posture of the workpiece 11, and the correction of the posture of the workpiece 11 is repeated. If the difference between the current posture and the target posture of the workpiece 11 is within the acceptable range, step S19: Yes is performed, and information indicating that the current posture of the workpiece 11 can now be determined to be the target posture is transmitted to the system control device 20, and the device proceeds to step S20. If the tilt of the posture of the workpiece 11 is determined to be significantly large and outside the range that can be corrected, the device may determine that it is an abnormality and interrupt the subsequent operations.

[0036] Next, in step S21, after the system control device 20 receives information indicating that the current orientation of the workpiece 11 can be determined to be the target orientation, it sends a command to the robot control device 30 to move the workpiece 11 to the box 12. The robot control device 30 operates the robot arm 31 to move the held workpiece 11 to the box 12. The position where the workpiece 11 is placed is changed depending on the type of workpiece 11 and the number of times it has been taken out, if there are partitions in the box 12. When moving the workpiece 11, it is desirable to provide intermediate points as appropriate so as not to interfere with the box 10 or box 12.

[0037] Then, in step S18, the robot control device 30 operates the holding member 42 of the robot hand 40 to release the workpiece 11 and places the workpiece 11 in the box 12. The robot control device 30 then transmits information to the system control device 20 indicating that the workpiece 11 has been placed in the box 12, and the control flow ends.

[0038] Figure 6 is a schematic diagram showing a modified example of the robot system 1000 of this embodiment. Figure 7 is a schematic diagram showing a modified example of the robot hand 40 of this embodiment. The robot hand 40 shown in Figures 6 and 7 has an imaging device 44 in addition to a palm portion 41, a holding member 42, and a contact member 43. The imaging device 44 generally includes a camera, lens, and lighting. The imaging device 44 is connected to an image processing device 50 via wiring inside the robot arm 31, and the image processing device 50 controls the imaging device 44 and processes the images captured by the imaging device 44. As shown in Figure 7, the imaging device 44 is positioned so as to acquire the orientation of the workpiece 11 from the palm portion 41. The image processing performed by the image processing device 50 includes, for example, position recognition of the mounting shape of boxes 10 and 12, or position recognition of the workpiece 11. Image processing and synthesis to improve recognition accuracy are also included. The orientation of the workpiece 11 may also be acquired by an on-hand camera.

[0039] As described above, according to this embodiment, while the workpiece 11 is held by the holding member 42, the relative position between the holding member 42 and the contact member 43 can be displaced. This allows the holding member 42 and / or the contact member 43 to correct the posture of the workpiece 11 and maintain the posture of the workpiece 11 in a predetermined state, even when the end of the workpiece 11 is held in a position where the posture of the workpiece 11 changes due to its own weight. Therefore, operations that require the holding position of the workpiece 11 to be fixed and the posture of the workpiece 11 to be maintained in a predetermined state can be performed, such as placing the workpiece 11 in a box 12 that conforms to the shape of the workpiece 11, or inserting the workpiece 11 into another workpiece. Furthermore, it is possible to perform these operations while reducing interference between the holding member 42 and the box 12 or another workpiece.

[0040] (Second embodiment) Next, the second embodiment will be described in detail. In the following, the same reference numerals will be used for components that are the same as or equivalent to those in the first embodiment, and their descriptions will be omitted or simplified. The focus will be on the differences from the first embodiment.

[0041] Figure 8 is a schematic diagram showing the robot hand 40 in this embodiment. Figure 8(a) is a perspective view of the robot hand 40, Figure 8(b) is an XY plan view (top view) of the robot hand 40 holding the workpiece 11, and Figure 8(c) is a YZ plan view (side view) of the robot hand 40 holding the workpiece 11.

[0042] As shown in Figure 8(a), the holding member 42 has the function of being displaced in the direction of operation (holding direction) when holding the workpiece 11. This may also be combined with the function of moving the holding member 42 in order to hold the workpiece 11. That is, the holding members 42 are each provided on the palm portion 41 so that they can move closer to or further away from each other independently. In addition, the contact member 43 has the function of moving closer to the holding member 42.

[0043] As shown in Figure 8(b), if the posture of the workpiece 11 is tilted in the XY plane, each of the holding members 42 is displaced in the +X direction. If the posture of the workpiece 11 cannot be sufficiently corrected by simply displacing each of the holding members 42 in one direction, each of the holding members 42 may also be moved in the Y direction. Alternatively, one of the holding members 42 may be displaced in the Y direction to hold the workpiece 11 in a position where the holding member 42 is shifted in the Y direction, and from this state, one of the holding members 42 may be displaced in the X direction. Furthermore, if the posture of the workpiece 11 is tilted in the YZ plane, the contact member 43 is displaced. By combining these operations, it is possible to correct the tilt of the workpiece 11 in both the XY and YZ planes.

[0044] As described above, according to this embodiment, while the workpiece 11 is held by the holding member 42, the relative position between the holding member 42 and the contact member 43 can be displaced. This allows the holding member 42 and / or the contact member 43 to correct the posture of the workpiece 11 and maintain the posture of the workpiece 11 in a predetermined state, even when the workpiece 11 is held at its end and its posture changes due to its own weight. Therefore, it is possible to perform operations where the holding position of the workpiece 11 is fixed and it is required to maintain the posture of the workpiece 11 in a predetermined state, such as placing the workpiece 11 in a box 12 that conforms to the shape of the workpiece 11, or inserting the workpiece 11 into another workpiece. Furthermore, it is possible to perform these operations while reducing interference between the holding member 42 and the box 12 or another workpiece. In addition, it becomes possible to correct the posture of the workpiece 11 in different planes, and the accuracy of the holding posture of the workpiece 11 can be improved. In this embodiment, the case in which the contact member 43 is brought closer to the holding member 42 is used as an example, but the embodiment is not limited to this. The holding member 42 may be brought close to the contact member 43, or the holding member 42 and the contact member 43 may be brought close to each other. Furthermore, the various embodiments and modifications described above may be combined and implemented.

[0045] (Third embodiment) Next, a third embodiment will be described in detail. In the following, the same reference numerals will be used for components that are the same as or equivalent to those in the various embodiments described above, and their descriptions will be omitted or simplified. The focus will be on the differences from the various embodiments described above. In this embodiment, in order to correct the orientation of the workpiece 11, a holding member 42, a contact member 43, and a restricting part that restricts the contact position with the workpiece 11 from shifting are provided.

[0046] Figure 9 is a schematic diagram showing the robot hand 40 in this embodiment. Figure 9(a) is a perspective view showing the robot hand 40 holding the workpiece 11. Figure 9(b) is a cross-sectional view AA of the robot hand 40 holding the workpiece 11, and Figure 9(c) is a cross-sectional view BB of the robot hand 40 holding the workpiece 11.

[0047] As shown in Figure 9(b), in the robot hand 40 of this embodiment, each of the holding members 42 is provided with a V-shaped groove that penetrates in the Y direction as a restricting portion. The outer diameter portion of the workpiece 11 is held by the restricting portion of the holding member 42. In Figure 9(b), each of the holding members 42 is provided with a restricting portion, but it may be any of the holding members 42. Also, as shown in Figure 9(c), in the robot hand 40 of this embodiment, the contact member 43 is provided with a V-shaped groove that penetrates in the Y direction as a restricting portion. The restricting portion of the contact member 43 is brought into contact with the inner diameter portion of the workpiece 11. This makes it possible to reduce the displacement of the holding position of the workpiece 11. Furthermore, it is possible to uniquely determine the position of the workpiece 11 relative to the holding member 42 or the contact member 43 when the workpiece 11 is held.

[0048] Figure 10 shows a modified example of the restricting portion in this embodiment. Figure 10(a) is a cross-sectional view AA of the robot hand 40 holding the workpiece 11, cut in the same direction as in Figure 9(a), and Figure 10(b) is a cross-sectional view BB of the robot hand 40 holding the workpiece 11, cut in the same direction as in Figure 9(a).

[0049] As shown in Figure 10(a), in the robot hand 40 of this embodiment, each of the holding members 42 is provided with an arc-shaped groove that penetrates in the Y direction as a restricting portion. The outer diameter portion of the workpiece 11 is held by the restricting portion of the holding member 42. In Figure 10(a), each of the holding members 42 is provided with a restricting portion, but it may be any of the holding members 42. Also, as shown in Figure 10(b), in the robot hand 40 of this embodiment, the contact member 43 is provided with an arc-shaped groove that penetrates in the Y direction as a restricting portion. The restricting portion of the contact member 43 is brought into contact with the inner diameter portion of the workpiece 11. This makes it possible to reduce the displacement of the holding position of the workpiece 11. Furthermore, it is possible to uniquely determine the position of the workpiece 11 relative to the holding member 42 or the contact member 43 when the workpiece 11 is held.

[0050] Figure 11 shows a modified example of the restricting portion in this embodiment. Figure 11(a) is a cross-sectional view AA of the robot hand 40 holding the workpiece 11, cut in the same direction as in Figure 9(a), and Figure 11(b) is a cross-sectional view BB of the robot hand 40 holding the workpiece 11, cut in the same direction as in Figure 9(a).

[0051] As shown in Figure 11(a), in the robot hand 40 of this embodiment, each of the holding members 42 is provided with a friction member as a restricting portion in the part that contacts the outer diameter portion. The outer diameter portion of the workpiece 11 is held by the restricting portion of the holding member 42. In Figure 11(a), each of the holding members 42 is provided with a restricting portion, but it may be any of the holding members 42. Also, as shown in Figure 11(b), in the robot hand 40 of this embodiment, the contact member 43 is provided with a friction member as a restricting portion in the part that contacts the inner diameter portion. The restricting portion of the contact member 43 is brought into contact with the inner diameter portion of the workpiece 11. The friction member can be, for example, urethane rubber or a polymer compound such as silicone resin. If surface scratches on the workpiece 11 are not a concern, the entire surface or a part of the holding member 42 may be roughened by cutting or shot blasting. According to this embodiment, the coefficient of friction between the workpiece 11 and the holding member 42 and / or contact member 43 can be increased compared to when no friction member is added, and the displacement of the holding position of the workpiece 11 can be suppressed. Furthermore, when the workpiece 11 is held, it becomes possible to uniquely determine the position of the workpiece 11 relative to the holding member 42 or the contact member 43.

[0052] As described above, according to this embodiment, while the workpiece 11 is held by the holding member 42, the relative position between the holding member 42 and the contact member 43 can be displaced. This allows the holding member 42 and / or the contact member 43 to correct the posture of the workpiece 11 and maintain the posture of the workpiece 11 in a predetermined state, even when the end of the workpiece 11 is held in a position where the posture of the workpiece 11 changes due to its own weight. Therefore, operations that require the holding position of the workpiece 11 to be fixed and the posture of the workpiece 11 to be maintained in a predetermined state can be performed, such as placing the workpiece 11 in a box 12 that conforms to the shape of the workpiece 11, or inserting the workpiece 11 into another workpiece. Furthermore, it is possible to perform these operations while reducing interference between the holding member 42 and the box 12 or another workpiece. In addition, the restricting part makes it possible to uniquely determine the position of the workpiece 11 relative to the holding member 42 or the contact member 43 when the workpiece 11 is held, thereby improving the accuracy of correcting the tilt of the posture of the workpiece 11. Note that the restricting part may be implemented by combining at least two of V-grooves, arc grooves, and friction members.

[0053] (Fourth embodiment) Next, the fourth embodiment will be described in detail. In the following, the same reference numerals will be used for components that are the same as or equivalent to those in the various embodiments described above, and their descriptions will be omitted or simplified. The focus will be on the differences from the various embodiments described above.

[0054] Figure 12 is a schematic diagram showing the robot system 1000 according to this embodiment. For the sake of explanation, the boxes 10 and 12 are not shown in Figure 12. As can be seen from Figure 12, in this embodiment, the posture of the workpiece 11 is acquired by one or more sensors 53. Here, the sensor 53 is depicted as a transmissive photoelectric sensor, which is an example of an optical sensor, but it is not limited to transmissive or photoelectric sensors. The robot control device 30 then acquires the information from these sensors 53. In this embodiment, the robot control device 30 acquires the information from the sensor 63, but a separate sensor control device, which is composed of a computer including a microprocessor, similar to the system control device 20, may also be provided.

[0055] Figure 13 is a diagram illustrating the correction of the posture of the workpiece 11 in this embodiment. Figure 14 is a control flowchart executed when correcting the posture of the workpiece 11 in this embodiment. The control flow shown in Figure 14 is executed by the CPUs of each control device working together via communication. From Figure 14, in this embodiment, steps S25, S26, S28, and S29 are executed instead of steps S15, S16, S18, and S19 to acquire the posture of the workpiece 11.

[0056] As shown in Figures 13 and 14, first, in step S25, the system control device 20 sends a command to the robot control device 30 to acquire the posture of the workpiece 11. The robot control device 30 then moves the robot arm 31 so that the tip of the workpiece 11 obstructs the optical axis of the sensor 53, while the robot hand 40 is holding the workpiece 11, and scans the workpiece 11. The position and / or posture of the robot hand 40 at the moment the sensor 53 detects the tip of the workpiece 11 is acquired from an encoder or the like mounted on the robot arm 31.

[0057] In step S26, the robot control device 30 calculates the difference Δz between the acquired position and / or orientation of the robot hand 40 and the position and / or orientation of the robot hand 40 that would be acquired based on the sensor 53 if it is determined that there is no tilt in the orientation of the workpiece 11. This makes it possible to estimate the orientation of the workpiece 11 geometrically. Based on this value, the amount of displacement Δz' that displaces the holding member 42 and / or contact member 43 can be calculated, thereby correcting the orientation of the workpiece 11.

[0058] Then, in step S17, the posture of the workpiece 11 is corrected based on the amount of movement Δz'. Then, in step S28, the robot control device 30, while holding the workpiece 11 with the robot hand 40, scans the workpiece 11 so that the tip of the workpiece 11 obstructs the optical axis of the sensor 53 to acquire information about the posture of the workpiece 11. Then, in step 29, it is determined whether the acquired position and / or posture of the robot hand 40 can be determined to be the position and / or posture of the target robot hand 40. In this determination, an acceptable range is set for the position and / or posture of the robot hand 40 that would be acquired based on the sensor 53 if it is determined that there is no tilt in the posture of the workpiece 11. If it is within the acceptable range, the process proceeds to step S20. If it is outside the acceptable range, the process returns to just before step S26 and the posture correction operation of the workpiece 11 is repeated.

[0059] As described above, according to this embodiment, while the workpiece 11 is held by the holding member 42, the relative position between the holding member 42 and the contact member 43 can be displaced. This allows the holding member 42 and / or the contact member 43 to correct the posture of the workpiece 11 and maintain the posture of the workpiece 11 in a predetermined state, even when the workpiece 11 is held at its end and its posture changes due to its own weight. Therefore, operations can be performed where the holding position of the workpiece 11 is fixed and it is required to maintain the posture of the workpiece 11 in a predetermined state, such as placing the workpiece 11 in a box 12 that conforms to the shape of the workpiece 11, or inserting the workpiece 11 into another workpiece. Furthermore, it is possible to perform these operations while reducing interference between the holding member 42 and the box 12 or another workpiece. In addition, it is possible to correct the posture of the workpiece 11 at a lower cost compared to using an imaging device.

[0060] In this embodiment, the correction amount for correcting the posture of the workpiece 11 is calculated using the sensor 53, but this is not the only method. For example, a force sensor or the like may be provided on the holding member 42, and the tilt of the posture of the workpiece 11 may be obtained based on the information obtained from the force sensor and the shape information of the workpiece 11. Alternatively, a slip sensor or the like may be provided on the holding member 42, and the tilt of the posture of the workpiece 11 may be obtained based on the information obtained from the slip sensor and the shape information of the workpiece 11.

[0061] (Fifth embodiment) Next, the fifth embodiment will be described in detail. In the following, the same reference numerals will be used for components that are the same as or equivalent to those in the various embodiments described above, and their descriptions will be omitted or simplified. The focus will be on the differences from the various embodiments described above. The workpiece 11 handled by the robot system 1000 has a known shape, and it can be assumed that there is a certain degree of reproducibility in the posture of the workpiece 11 when gripped by the robot hand 40. Therefore, even without a means of recognizing the posture of the workpiece, the posture of the workpiece 11 can be corrected by displacing the holding member 42 and / or contact member 43 by a preset amount.

[0062] Figure 15 is a flowchart of the operations performed on the workpiece 11 in this embodiment. The control flow shown in Figure 15 is executed by the CPUs of each control device working together via communication.

[0063] As shown in Figure 15, in step S11, the system control device 20 first sends a command to the robot control device 30, and the robot control device 30 operates the robot arm 31 to move the robot hand 40 to the top of the box 10. Before operating the robot hand 40, it is desirable to acquire the posture of the robot arm 31 and to move it by providing intermediate points as needed to avoid interference with the box 12 and box 10.

[0064] Next, in step S12, the robot control device 30 moves to a position to hold the workpiece 11 placed in the box 10. It is assumed that there are multiple places to place workpieces 11 inside the box 10. The robot arm 31 should have as many teaching points for holding positions as there are places to place workpieces 11, and it is desirable to provide appropriate intermediate points so that the robot hand 40 does not interfere with the box 10 or other workpieces 11 when moving from the upper position of the box 10 to the holding position.

[0065] Next, in step S13, the robot control device 30 moves the holding member 42 of the robot hand 40 in the direction of holding the workpiece 11 to hold the workpiece 11.

[0066] Next, in step S34, the holding member 42 and / or contact member 43 are displaced by a predetermined amount. The amount of movement (displacement) to be set may be experimentally determined based on the average of the tilt amount obtained by holding the actual workpiece 11 multiple times with the robot hand 40. Alternatively, the amount of movement may be set using a simulator capable of performing physical simulations. This corrects the tilt of the workpiece 11's posture. The robot control device 30 transmits information to the system control device 20 indicating that the correction of the workpiece 11's posture is complete.

[0067] Next, in step S20, the system control device 20 sends a command to the robot control device 30 to move the workpiece 11 to the box 12. The robot control device 30 operates the robot arm 31 to move the held workpiece 11 to the box 12. The position where the workpiece 11 is placed is changed depending on the type of workpiece 11 and the number of times it has been taken out, if there are partitions in the box 12. When moving the workpiece 11, it is desirable to provide intermediate points as appropriate so as not to interfere with the box 10 or box 12.

[0068] Then, in step S21, the robot control device 30 operates the holding member 42 of the robot hand 40 to release the workpiece 11 and place the workpiece 11 in the box 12. The robot control device 30 then transmits information to the system control device 20 indicating that the workpiece 11 has been placed in the box 12, and the control flow ends.

[0069] As described above, according to this embodiment, while the workpiece 11 is held by the holding member 42, the relative position between the holding member 42 and the contact member 43 can be displaced. This allows the holding member 42 and / or the contact member 43 to correct the posture of the workpiece 11 and maintain the posture of the workpiece 11 in a predetermined state, even when the workpiece 11 is held at its end and its posture changes due to its own weight. Therefore, operations can be performed where the holding position of the workpiece 11 is fixed and it is required to maintain the posture of the workpiece 11 in a predetermined state, such as placing the workpiece 11 in a box 12 that conforms to the shape of the workpiece 11, or inserting the workpiece 11 into another workpiece. Furthermore, it is possible to perform these operations while reducing interference between the holding member 42 and the box 12 or another workpiece. In addition, since there is no means to acquire the posture of the workpiece 11, it is possible to correct the posture of the workpiece 11 at an even lower cost. In this embodiment, the holding member 42 and / or the contact member 43 are displaced from a state in which the workpiece 11 is held in the box 10. However, if there is no risk of interference between the workpiece 11, the box 10, and the robot hand 40 when the robot hand 40 enters the box 10, the holding member 42 and / or contact member 43 may be moved to a predetermined position before entering the box 10. Alternatively, the holding member 42 and / or contact member 43 may be moved to a predetermined position in advance when it is determined that the workpiece 11 is to be removed.

[0070] (Other embodiments) The processing procedures of the embodiments described above are specifically executed by each CPU of each control device. Therefore, it is also possible to configure the device to read and execute a recording medium containing a control program for software capable of executing the above-described functions. In this case, the control program read from the recording medium itself will realize the functions of each embodiment described above, and the control program itself and the recording medium on which the control program is recorded will constitute the present invention.

[0071] Furthermore, in each embodiment, the computer-readable recording medium was described as a ROM, RAM, or flash ROM, and the program was stored in the ROM, RAM, or flash ROM. However, the present invention is not limited to these embodiments. The program for carrying out the present invention may be recorded on any recording medium that is computer-readable, and may be recorded on an SSD (Solid State Drive), etc. It may also be carried out by an imaging device equipped with the functions of the image processing device 50.

[0072] Furthermore, although the various embodiments described above have explained the case in which the robot arm 31 is a multi-joint robot arm having multiple joints, the number of joints is not limited to this. As a type of robot arm, a vertical multi-axis configuration was shown, but the same configuration can be implemented with different types of joints such as horizontal multi-joint type, parallel link type, and Cartesian robot.

[0073] Furthermore, the various embodiments described above are applicable to machines that can automatically perform actions such as extension and retraction, bending and straightening, vertical movement, horizontal movement, or rotation, or combinations thereof, based on information stored in a memory device provided in the control device.

[0074] Furthermore, the present invention is not limited to the embodiments described above, and many modifications are possible within the technical concept of the present invention. In addition, the effects described in the embodiments of the present invention are merely a list of the most preferred effects that result from the present invention, and the effects of the present invention are not limited to those described in the embodiments. Moreover, the various embodiments and modifications described above may be combined and implemented.

[0075] Furthermore, the disclosure of this embodiment includes the following items.

[0076] (Item 1) A robot hand capable of holding a workpiece, A first member that holds the workpiece, The workpiece is held by the first member and a second member is capable of contacting the workpiece, While the workpiece is held by the first member, the orientation of the workpiece is changed by displacing the first member or the second member. A robotic hand characterized by the following features.

[0077] (Item 2) In the robot hand described in item 1, The system acquires information regarding the orientation of the workpiece and changes the orientation of the workpiece by displacing the first member or the second member based on the information regarding the orientation of the workpiece. A robotic hand characterized by the following features.

[0078] (Item 3) In the robot hand described in item 2, Information regarding the orientation of the workpiece is acquired by at least one of the following: an imaging device, a light sensor, a force sensor, and a sliding sensor. A robotic hand characterized by the following features.

[0079] (Item 4) In the robot hand described in item 1, With the workpiece held by the first member, the posture of the workpiece is changed by displacing the first member or the second member based on a displacement amount set to correct the posture of the workpiece. A robotic hand characterized by the following features.

[0080] (Item 5) In a robot hand described in any one of items 1 to 4, Before holding the workpiece, the first member or the second member is displaced, and the workpiece is held in the displaced state. A robotic hand characterized by the following features.

[0081] (Item 6) In a robot hand described in any one of items 1 to 5, The first member or the second member is provided with a restricting portion for restricting the workpiece. A robotic hand characterized by the following features.

[0082] (Item 7) In the robot hand described in item 6, The regulating portion is at least one of a V-groove, an arc groove, or a friction member. A robotic hand characterized by the following features.

[0083] (Item 8) In the robot hand described in item 6 or 7, The restricting portion of the first member contacts the outer diameter portion of the workpiece, and the restricting portion of the second member contacts the inner diameter portion of the workpiece. A robotic hand characterized by the following features.

[0084] (Item 9) In a robot hand described in any one of items 1 through 8, The first member maintains a position away from the center of gravity of the workpiece, thereby ensuring reproducibility in the tilt of the workpiece's posture. A robotic hand characterized by the following features.

[0085] (Item 10) In a robot hand described in any one of items 1 through 9, The position of the second member is such that it is on the opposite side from the side in which the workpiece tilts. A robotic hand characterized by the following features.

[0086] (Item 11) In a robot hand described in any one of items 1 through 10, Having at least two of the aforementioned first members, The first members can move closer to or further apart from each other independently. The orientation of the workpiece is changed by displacing at least one of the two first members. A robotic hand characterized by the following features.

[0087] (Item 12) In a robot hand described in any one of items 1 through 11, When the aforementioned workpiece is brought into contact with another workpiece, depending on the position in which the first member holds the workpiece, the first member and the other workpiece may interfere with each other. A robotic hand characterized by the following features.

[0088] (Item 13) In a robot hand described in any one of items 1 through 12, The orientation of the workpiece is changed by bringing the first member or the second member closer to the other. A robotic hand characterized by the following features.

[0089] (Item 14) In a robot hand described in any one of items 1 through 13, The orientation of the workpiece is changed by moving the first member in the direction opposite to the direction of gravity of the workpiece, or by moving the second member in the direction of gravity of the workpiece. A robotic hand characterized by the following features.

[0090] (Item 15) In a robot hand described in any one of items 1 through 14, When the workpiece is held by the first member, the first member is positioned between the center of gravity of the workpiece and the second member. A robotic hand characterized by the following features.

[0091] (Item 16) In a robot hand described in any one of items 1 through 15, The first member is a holding member that holds the workpiece, and the second member is a contact member that contacts the workpiece. A robotic hand characterized by the following features.

[0092] (Item 17) A robotic system comprising a robotic hand and a robotic arm as described in any one of items 1 through 16.

[0093] (Item 18) A method for manufacturing articles, characterized by manufacturing articles using the robotic system described in item 17.

[0094] (Item 19) A method for controlling a robot hand capable of holding a workpiece, The aforementioned robot hand is A first member that holds the workpiece, The workpiece is held by the first member and a second member is capable of contacting the workpiece, While the workpiece is held by the first member, the orientation of the workpiece is changed by displacing the first member or the second member. A control method characterized by the following:

[0095] (Item 20) A control program capable of executing the control method described in item 19.

[0096] (Item 21) A computer-readable recording medium containing the control program described in item 20. [Explanation of symbols]

[0097] 10, 12 boxes 11 Work 20 System Control Units 21 Input device 30 Robot control devices 31 Robot Arm 40 Robot Hand 41 Palm 42 Retaining member 43 Contact Member 44, 52 Imaging device 50 Image Processing Devices 63 Sensors 1000 Robot Systems

Claims

1. A robot hand capable of holding a workpiece, A first member that holds the workpiece, The workpiece is held by the first member and has a second member that can contact the workpiece, While the workpiece is held by the first member, the orientation of the workpiece is changed by displacing the first member or the second member. A robotic hand characterized by the following features.

2. In the robot hand according to claim 1, The system acquires information regarding the orientation of the workpiece and changes the orientation of the workpiece by displacing the first member or the second member based on the information regarding the orientation of the workpiece. A robotic hand characterized by the following features.

3. In the robot hand according to claim 2, Information regarding the orientation of the workpiece is acquired by at least one of the following: an imaging device, a light sensor, a force sensor, and a sliding sensor. A robotic hand characterized by the following features.

4. In the robot hand according to claim 1, With the workpiece held by the first member, the posture of the workpiece is changed by displacing the first member or the second member based on a displacement amount set to correct the posture of the workpiece. A robotic hand characterized by the following features.

5. In the robot hand according to claim 1, Before holding the workpiece, the first member or the second member is displaced, and the workpiece is held in the displaced state. A robotic hand characterized by the following features.

6. In the robot hand according to claim 1, The first member or the second member is provided with a restricting portion for restricting the workpiece. A robotic hand characterized by the following features.

7. In the robot hand according to claim 6, The regulating portion is at least one of a V-groove, an arc groove, or a friction member. A robotic hand characterized by the following features.

8. In the robot hand according to claim 6, The restricting portion of the first member contacts the outer diameter portion of the workpiece, and the restricting portion of the second member contacts the inner diameter portion of the workpiece. A robotic hand characterized by the following features.

9. In the robot hand according to claim 1, The first member maintains a position away from the center of gravity of the workpiece, thereby ensuring reproducibility in the tilt of the workpiece's posture. A robotic hand characterized by the following features.

10. In the robot hand according to claim 1, The position of the second member is such that it is on the opposite side from the side in which the workpiece tilts. A robotic hand characterized by the following features.

11. In the robot hand according to claim 1, Having at least two of the first members, The first members can move closer to or further apart from each other independently. The orientation of the workpiece is changed by displacing at least one of the two first members. A robotic hand characterized by the following features.

12. In the robot hand according to claim 1, When the aforementioned workpiece is brought into contact with another workpiece, depending on the position in which the first member holds the workpiece, the first member and the other workpiece may interfere with each other. A robotic hand characterized by the following features.

13. In the robot hand according to claim 1, The orientation of the workpiece is changed by bringing the first member or the second member closer to the other. A robotic hand characterized by the following features.

14. In the robot hand according to claim 1, The orientation of the workpiece is changed by moving the first member in the direction opposite to the direction of gravity of the workpiece, or by moving the second member in the direction of gravity of the workpiece. A robotic hand characterized by the following features.

15. In the robot hand according to claim 1, When the workpiece is held by the first member, the first member is positioned between the center of gravity of the workpiece and the second member. A robotic hand characterized by the following features.

16. In the robot hand according to claim 1, The first member is a holding member that holds the workpiece, and the second member is a contact member that contacts the workpiece. A robotic hand characterized by the following features.

17. A robotic system comprising a robotic hand and a robotic arm according to any one of claims 1 to 16.

18. A method for manufacturing an article, characterized by manufacturing the article using the robot system described in claim 17.

19. A method for controlling a robot hand capable of holding a workpiece, The aforementioned robot hand is A first member that holds the workpiece, The workpiece is held by the first member and has a second member that can contact the workpiece, While the workpiece is held by the first member, the orientation of the workpiece is changed by displacing the first member or the second member. A control method characterized by the following:

20. A control program capable of executing the control method described in claim 19.

21. A computer-readable recording medium storing the control program described in claim 20.

Images