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

Abstract

To improve versatility in workpiece assembly. [Solution] A robot hand is provided having a first finger portion and a second finger portion that grip a workpiece by moving closer to or further apart from each other, wherein each of the first finger portion and the second finger portion is provided with at least two ends that come into contact with the workpiece, and in the direction of approaching or separating the first finger portion and the second finger portion, the end on the side opposite to the workpiece assembly direction is located closer to the center than the end on the side of the workpiece assembly direction, with reference to the center of the arc passing through at least three of the ends.

Description

Technical Field

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

Background Art

[0002] Generally, for shaft parts mounted on industrial products, devices, etc., a retaining ring is required to prevent the shaft from falling out in the longitudinal direction of the shaft. Among them, a ring-shaped E-ring (E-ring) that is fitted into a groove cut in the edge of the shaft is widely used. In particular, products having a mechanism for conveying paper, such as printers, have many shaft parts, and E-rings are frequently used. As a general method for assembling an E-ring, the E-ring is grasped with a radio pliers, the opening of the E-ring is placed on the groove of the shaft, and then the E-ring is released. Then, the E-ring and the shaft are clamped together in a direction orthogonal to the longitudinal direction of the shaft (the opening direction of the E-ring) with the radio pliers, and the E-ring is fitted into the groove of the shaft while deforming the E-ring. The standard of the E-ring is defined in JIS B 2085, but since most of them are 1 mm or less in thickness, it is difficult to grasp them with radio pliers. In addition, since the E-ring is circular, if attention is not paid to the gripping position of the E-ring when clamping with radio pliers, the radio pliers will slip along the circular shape. Thus, the assembly of the E-ring is considered to be difficult work, and automation of the assembly is desired. In Patent Document 1 below, a robot hand that grips a dedicated tool for assembling an E-ring is disclosed. The dedicated tool in Patent Document 1 holds the opposite side of the assembly direction of the E-ring (the opening direction of the E-ring), and has a shape like a forked extension extending to the opposite side of the assembly direction of the E-ring. Patent Document 1 discloses a method of gripping the E-ring with a dedicated tool and assembling the E-ring from above the groove of the shaft in the E-ring assembly direction orthogonal to the longitudinal direction of the shaft.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] Here, for example, when assembling an E-ring as a workpiece, there isn't always enough space available for assembly. For instance, if the dedicated jig shown in Patent Document 1 cannot access the space for assembling the E-ring, assembling the E-ring becomes difficult.

[0005] This invention improves versatility in workpiece assembly. [Means for solving the problem]

[0006] To solve the above-mentioned problems, the present invention provides a robot hand having a first finger portion and a second finger portion that grip a workpiece by moving closer to or further apart from each other, wherein each of the first finger portion and the second finger portion is provided with at least two ends that contact the workpiece, and in the direction of approaching or separating the first finger portion and the second finger portion, the end portion on the side opposite to the workpiece assembly direction is located closer to the center than the end portion on the workpiece assembly direction side, with reference to the center of the arc passing through at least three of the ends. [Effects of the Invention]

[0007] According to the present invention, the versatility in workpiece assembly can be improved. [Brief explanation of the drawing]

[0008] [Figure 1] This is a diagram illustrating the assembly of the E-ring in the embodiment. [Figure 2] This is a schematic diagram of the robot system 1000 in an embodiment. [Figure 3] This is a block diagram of the robot system 1000 in an embodiment. [Figure 4] This is a schematic diagram of the robot hand 300 in the embodiment. [Figure 5] This figure shows a comparison between the state in which the E-ring is gripped by the fingers 311 and 312 in the embodiment and the state in which the E-ring is gripped by the fingers 711 and 712 in the comparative example. [Figure 6] This is a control flowchart in the embodiment. [Figure 7] This is a diagram illustrating the assembly of the E-ring in the embodiment. [Figure 8] This is a diagram illustrating the assembly of the E-ring in the embodiment. [Figure 9] This is a diagram illustrating the assembly of the E-ring in the embodiment. [Figure 10] This is a diagram illustrating the assembly of the E-ring in the embodiment. [Figure 11] This is a diagram illustrating the assembly of the E-ring in the embodiment. [Figure 12] This diagram shows the state in which the E-ring is gripped by the finger portions 311 and 312 in the embodiment. [Figure 13] This is a diagram illustrating the assembly of the E-ring in the embodiment. [Figure 14] This is a diagram illustrating the assembly of the E-ring in the embodiment. [Figure 15] This is a schematic diagram of the shapes of the finger portions 311 and 312 in the embodiment. [Figure 16] This is a schematic diagram of the shapes of the finger portions 311 and 312 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) First, the problems with the present invention will be described in detail. Figure 1 illustrates a case where the assembly space for the E-ring is narrow. Figure 1(a) is a perspective view, and Figure 1(b) is a cross-sectional view of AA shown in Figure 1(a). From Figures 1(a) and (b), a shaft is supported by a sheet metal part via a shaft support part, and a groove into which the E-ring is assembled is formed in the shaft. Furthermore, a constriction is formed in the sheet metal part around the groove. In the assembly of the E-ring in the constricted portion of the sheet metal part as shown in Figures 1(a) and (b), the area around the groove of the shaft into which the E-ring should be assembled is constricted by the sheet metal part, making it difficult to access the groove of the shaft with a special tool, and thus making it difficult to assemble the E-ring.

[0011] FIG. 2 is an explanatory diagram showing a schematic configuration of the robot system 1000 in the present embodiment. The robot system 100 in the present embodiment includes a robot arm 200, a robot hand 300, a control device 500, and an external input device 600. The robot arm 200 and the robot hand 300 operate on a workpiece W. The workpiece W is an E-ring or the like. The external input device 600 is connected to the control device 500 via IF504. The external input device 600 is, for example, a teaching pendant equipped with a touch panel, and it is assumed that the touch panel has a GUI (Graphical User Interface).

[0012] The robot arm 200 is an articulated robot arm in the present embodiment, and the base of the robot arm 200 is fixed. The robot arm 200 has a base portion 210 connected by a plurality of joints J1, J2, J3, J4, J5, J6 that rotate, and a plurality of links 201, 202, 203, 204, 205, 206. The link 201 is connected to the base portion 210. Each joint of the robot arm 200 is provided with a motor as a drive source for driving these joints, a speed reducer, and an encoder as position detection means for detecting the rotation angle of the motor. The installation position and output method of the encoder are not limited. Also, a torque sensor for acquiring information regarding force may be provided at each joint. A robot hand 300 is attached to the link 206 at the tip of the robot arm 200. The robot hand 300 and the link 206 can rotate by the joint J6. By driving the joints J1 to J6 of the robot arm 200, the robot arm 200 can be set in various postures, and the robot hand 300 can be set in various positions and postures.

[0013] A robot hand 300, which is an end effector, is attached to the link 206 of the robot arm 200. The robot hand 300 includes a hand base 301, and finger portions 311 and 312 are provided on the hand base 301. The finger portion 311 may be referred to as the first finger portion, and the finger portion 312 may be referred to as the second finger portion.

[0014] The control device 500 has a CPU (Central Processing Unit) 501, a ROM (Read Only Memory) 502, and a RAM (Random Access Memory) 503. It also has an IF (Inter Face) 504 responsible for communication with the outside. These are configured to be able to communicate with each other via a bus 505. The ROM 502 stores programs for controlling the corresponding drive units according to various operations of the robot arm 200, and data necessary for such control, etc. The RAM 503 functions as a working area for the CPU 501.

[0015] A program 502e is recorded in the ROM 502. The program 502e is a program for causing a computer, that is, the CPU 501, to execute the output of commands for controlling the robot arm 200, the robot hand 300, and other devices. The RAM 503 is used to temporarily store programs for executing the control of the entire system, the execution timing of operations in each control target, data such as control commands, etc. The CPU 501 acquires, for example, data transmitted from various sensors by receiving it at the I / F 504. Also, the CPU 501 can transmit a command as a control target value to a control device for controlling each control target via the I / F 504 based on a program and data input by the user.

[0016] In this embodiment, the program 502e is recorded in the ROM 502, but it is not limited to this. The program 502e 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 502e 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.

[0017] The IF504 functions as an interface for communication with the robot arm 200, the robot hand 300, and the external input device 600. The CPU 501 calculates the angles that each joint should take relative to the target position and orientation of the tip of the robot arm 200, which is the destination of the robot hand 300. It then outputs command values ​​via the IF504 to the servo circuits that control the motors of each joint, thereby driving and controlling each joint of the robot arm 200. This allows the robot hand 300 to manipulate the workpiece W.

[0018] The external input device 600 could be an operating device such as a teaching pendant (TP), but it could also be another computer device (PC or server) capable of editing the robot program. The external input device 600 can be connected to the control device 500 via wired or wireless communication means and has user interface functions such as robot operation and status display. The CPU 501 receives teaching point data input from the external input device 600 via the IF 504. Based on the teaching point data input from the external input device 600, the CPU 501 can generate trajectories for the robot arm 200 and robot hand 300 and transmit them to the robot arm 200 and robot hand 300 as control target values ​​via the IF 504. In this embodiment, control by the CPU 501 has been described as an example, but it is not limited to this, and it may be controlled by at least one CPU, i.e., multiple CPUs, or by a multi-core CPU.

[0019] Figure 3 is a block diagram showing the structure of the control system in the robot system 1000 according to this embodiment. As shown in Figure 3, the robot hand 300 has finger motors 302 for moving the finger portions 311 and 312 closer to or further apart from each other, and a hand control circuit 303 for controlling the finger motors 302. The control device 500 sends commands to the hand control circuit 303. The hand control circuit 303 controls the finger motors 302 to operate according to the commands from the control device 500. The finger portions 311 and 312 are configured to be driven by the operation of the finger motors 302. In this way, the control device 500 can cause the robot hand 300 to grasp or release a workpiece W by sending commands to the hand control circuit 303.

[0020] The robot arm 200 has motors J1 211, J2 212, J3 213, J4 214, J5 215, and J6 216, which drive joints J1 to J6, i.e., links 201 to 206, respectively. It also has an arm control circuit 220 that controls these motors. The control device 500 sends commands to the arm control circuit 220 based on the teaching data. The arm control circuit 220 controls each motor to operate according to the commands from the control device 500. In this way, the control device 500 can rotate or swivel each of the links 201 to 206 by sending commands to the arm control circuit 220. Therefore, the control device 500 can move the robot hand 300 to the taught position and orientation in the workspace where the robot system 1000 is located. Furthermore, it is also acceptable to provide control circuits for each of the J1 motor 211, J2 motor 212, J3 motor 213, J4 motor 214, J5 motor 215, and J6 motor 216.

[0021] With the above configuration, the robot arm 200 can move the robot hand 300 to any position and perform a predetermined task. For example, by using a predetermined workpiece and other workpieces as materials and performing a process of assembling the predetermined workpiece and other workpieces, an assembled workpiece can be manufactured as a deliverable. In addition to assembling workpieces, the robot hand 300 may also be used to grasp a predetermined tool and process a predetermined workpiece for manufacturing. Thus, the robot system 1000 can manufacture goods.

[0022] Figure 4 is a schematic diagram of the robot hand 300 in this embodiment. Figure 4(a) is a perspective view of the robot hand 300. Figure 4(b) is an XZ plan view of the finger portions 311 and 312. In Figure 4(b), the hand base 301 is not shown for illustrative purposes. As shown in Figure 4(a), the robot hand 300 is provided with symmetrical finger portions 311 and 312. The finger portions 311 and 312 are made of a metal material such as SUS (Steel Use Stainless), are movable relative to the hand base 301, and move toward or away from each other in conjunction in direction S1. Direction S2 is the longitudinal direction of the finger portions 311 and 312.

[0023] As shown in Figures 4(a) and 4(b), the finger portions 311 and 312 have gripping surfaces 321 and 322 for attaching the E-ring, and support surfaces 331 and 332 for supporting the surface of the E-ring. The gripping surfaces 321 and 322 have an arc shape that matches the outer shape of the E-ring, allowing the E-ring to be gripped with the entire gripping surface. The relief portions 341 and 342 are shaped to prevent the shaft to be assembled from interfering with the finger portions 311 and 312 when the E-ring is assembled.

[0024] The finger portions 311 and 312 shown in Figure 4(b) are in a position to grip the E-ring. In the state shown in Figure 4(b), the arc P passing through the ends 351 and 352 on the direction S3, which is the direction in which the E-ring is assembled, and the ends 361 and 362 on the opposite side of the gripping surfaces 321 and 322, is made to match the outer shape of the E-ring. Here, let L1 be a line segment passing through the center C of arc P and parallel to direction S1, which is the direction in which the finger portions 311 and 312 move closer together or further apart. Let angle a be the angle formed by line segment L2 passing through the center C of arc P and end 351, and let angle b be the angle formed by line segment L1 and line segment L3 passing through the center C of arc P and end 361. In this embodiment, gripping surfaces 321 and 322 are formed such that angle a is smaller than angle b. It is preferable that angle a is 12° or less and angle b is 45° or more, but this is not limited to these. The positional relationship between these ends 351, 352, 361, and 362 allows the E-ring, when gripped by the robot hand 300, to withstand the reaction force generated during E-ring assembly without hindering the deformation of the E-ring. The gripping surface 321 may be referred to as the first surface, and the gripping surface 322 as the second surface. The support surface 331 may be referred to as the third surface, and the support surface 332 as the fourth surface.

[0025] Figure 5 is a diagram for comparison between E-ring gripping by the robot hand 300 in this embodiment and E-ring gripping by the robot hand 700 in the comparative example. Figure 5(a) shows E-ring gripping by the robot hand 300 in this embodiment, and Figure 5(b) shows E-ring gripping by the robot hand 700 in the comparative example.

[0026] In Figure 5(b), the robot hand 700 in the comparative example has finger portions 711 and 712. The finger portions 711 and 712 shown in Figure 5(b) are in a position to grip the E-ring. In the state shown in Figure 5(b), the arc P passing through the ends 751 and 752 on the side of direction S3, which is the E-ring assembly direction, and the ends 761 and 762 on the opposite side, is made to match the outer shape of the E-ring. Here, let L1 be a line segment passing through the center C of arc P and parallel to direction S1, which is the direction of approach or separation of the finger portions 711 and 712. Let angle a be the angle made by line segment L2 passing through the center C of arc P and end 751, and let angle b be the angle made by line segment L1 and line segment L3 passing through the center C of arc P and end 761. In this case, in the comparative example, ends 751 and 752 and ends 761 and 762 are formed such that angles a and b are equal. For comparison, finger portions 711 and 712 have the same outer diameter as finger portions 311 and 312 in this embodiment. Line segment L1 may be referred to as the first line segment, line segment L2 as the second line segment, and line segment L3 as the third line segment. Angle a may be referred to as the first angle, and angle b as the second angle.

[0027] As shown in Figure 5(a), because angle a is smaller than angle b, the distance between end 351 and the workpiece end 71 of the E-ring's notch, and the distance between end 352 and the workpiece end 72 of the E-ring's notch, can be made larger than in the comparative example. That is, as shown in Figure 5(b), the distance between end 751 and the workpiece end 71 of the E-ring's notch, and the distance between end 752 and the end 72 of the E-ring's notch, can be made larger. Furthermore, when the E-ring is assembled to the shaft, it deforms in the S1 direction, and the ends 71 ​​and 72 of the E-ring's notch deform more, attempting to widen the gripping position in the S1 direction. However, because ends 351 and 352 are far from ends 71 ​​and 72 of the E-ring's notch, the displacement of the gripping position due to the deformation of the E-ring is small, and a stable grip can be achieved.

[0028] Furthermore, in direction S1, which is the direction in which the finger portions 311 and 312 move closer together or further apart, end 361 is positioned closer to the center C than end 351. Similarly, in direction S1, which is the direction in which the finger portions 311 and 312 move closer together or further apart, end 362 is positioned closer to the center C than end 352. Moreover, in direction S1, which is the direction in which the finger portions 311 and 312 move closer together or further apart, end 351 and end 361 are positioned closer to the center C than the furthest point on the finger portion 311 that is furthest from the center C. Moreover, in direction S1, which is the direction in which the finger portions 311 and 312 move closer together or further apart, end 352 and end 362 are positioned closer to the center C than the furthest point on the finger portion 312 that is furthest from the center C. Furthermore, the midpoint between end 351 and end 361 in direction S3, which is the assembly direction of the E-ring, and the midpoint between end 352 and end 362 in direction S3, which is the assembly direction of the E-ring, are located on the opposite side of direction S3 with respect to the center C.

[0029] As a result, in this embodiment, the impact of E-ring deformation during assembly on the finger portions 311 and 312 is reduced compared to the comparative example, and the E-ring can be gripped stably. In particular, as in this embodiment shown in Figure 5(a), when the angle a is 12° or less, the gripping position of the E-ring can be moved even further away from the other workpiece end 81 and workpiece end 82 of the notched surface. Therefore, the impact of E-ring deformation on the finger portions 311 and 312 can be further reduced.

[0030] Furthermore, as shown in Figure 5(a), when angle b is greater than angle a, the ends 361 and 362 can be positioned to easily receive the assembly reaction force received in the opposite direction of direction S3, which is the E-ring assembly direction. In the comparative example shown in Figure 5(b), the ends 761 and 762 are positioned to be less susceptible to the assembly reaction force received in the opposite direction of direction S3, causing the E-ring to slip against the finger portions 711 and 712. In particular, as in this embodiment shown in Figure 5(a), when angle b is 45° or greater, the assembly reaction force can be received by the rigidity of the finger portions rather than relying on the frictional force of the gripping surface which depends on the gripping force, making it easier to maintain grip on the E-ring. Also, an angle b of 75° or less is preferable. This is because if angle b is large, the finger portions 311 and 312 become larger relative to the E-ring, making it difficult to enter narrow spaces. In particular, in direction S3, which is the E-ring assembly direction, there is an assembly stroke, and the E-ring is accessed from the top of the shaft. Therefore, space is secured for access.

[0031] Based on the above, as shown in the embodiment in Figure 5(a), angle a < angle b (particularly angle a ≤ 12°, 45° ≤ angle b ≤ 75°) is set. This results in a shape that allows the finger portion to withstand the reaction force during E-ring assembly while receiving the force due to the deformation of the E-ring, compared to the comparative example shown in Figure 5(b) where angle a = angle b. Therefore, the finger portions 311 and 312 of this embodiment can be made into a fingertip shape suitable for E-ring assembly. Because of this fingertip shape, the E-ring can be grasped with the fingertips, and the assembly can be performed by entering into a narrow space.

[0032] Next, a method for assembling an E-ring using the robot hand 300 of this embodiment will be described. Figure 6 is a control flowchart for assembling an E-ring with the robot hand 300. Figures 7 to 11 show the state when assembling an E-ring in this embodiment. The control flow shown in Figure 6 is executed by the CPU and control circuit of each control device working together via communication. In Figures 7 to 11, the hand base 301 and sheet metal parts are omitted from the illustration for illustrative purposes.

[0033] As shown in Figure 6, in step S1, the control device 500 uses the robot arm 200 and the robot hand 300 to position the finger parts 311 and 312 above the stocker (not shown) where multiple E-rings are lined up and stocked (Figure 7).

[0034] Next, in step S2, the control device 500 uses the finger parts 311 and 312 to grasp one of the E-rings located at the end of the stocker (Figure 8). Specifically, the support surfaces 331 and 332 of the finger parts 311 and 312 are brought into contact with the surface of the E-ring in direction S2, and the gripping surfaces 321 and 322 grip the side of the E-ring in direction S1. In this case, the thickness of the gripping surfaces 321 and 322 in direction S2 is made thinner than or equal to the thickness of a single E-ring so that only one of the multiple E-rings in a row is grasped. For example, for an E-ring with an inner diameter of 5 mm and a thickness of 0.7 mm, the thickness of the gripping surfaces 321 and 322 is preferably about 0.6 mm.

[0035] Next, in step S3, while gripping the E-ring with the finger parts 311 and 312, the E-ring is transported to the upper part of the groove on the shaft to which the E-ring will be installed (Figure 9). Here, since the E-ring is gripped by the relatively small finger parts 311 and 312, it is possible to access the groove on the shaft even if there is a restriction of sheet metal parts around the groove on the shaft to which the E-ring is to be installed.

[0036] Next, in step S4, the E-ring is moved in direction S3 while still being held, thereby bringing the E-ring into contact with the groove on the shaft (Figure 10).

[0037] Next, in step S5, the E-ring is moved further in direction S3 to assemble it into the groove of the shaft (Figure 11). This completes the control flow.

[0038] When assembling the E-ring into the groove, relief portions 341 and 342 are formed on the finger portions 311 and 312, so that the shaft and the finger portions 311 and 312 can avoid interference. Also, when the E-ring is assembled into the groove, the notched surfaces 61 and 62 come into contact with the groove, causing the notched surfaces 61 and 62 to deform and the E-ring to open in direction S1. The amount of opening is larger at the workpiece ends 71 ​​and 72 of the E-ring notch surface, so if the outer shape near the workpiece ends 71 ​​and 72 of the E-ring notch surface is gripped, it may hinder the deformation of the E-ring and potentially hinder the assembly of the E-ring onto the shaft.

[0039] Therefore, as described above, in this embodiment, the finger portions 311 and 312 are formed with ends 351 and 352 such that they grip the outer shape of the E-ring's notched surface at a position away from the workpiece ends 71 ​​and 72, as shown in Figure 5(a). This reduces the influence of the gripping of the finger portions 311 and 312 on the deformation of the E-ring during assembly, and allows for stable gripping of the E-ring even during assembly. In this embodiment, the finger portions 311 and 312 are configured to tilt slightly due to the deformation force of the E-ring and continue to grip in accordance with the opening amount of the E-ring, but the gripping may be controlled to widen the gap between the finger portions in accordance with the deformation of the E-ring.

[0040] Furthermore, when the E-ring is assembled into the groove, it not only deforms but also receives an assembly reaction force from the shaft. This assembly reaction force may cause the E-ring to shift away from the gripping surfaces 321 and 322. Therefore, as shown in Figure 5(a), the finger portions 311 and 312 of this embodiment have end portions 361 and 362 formed to easily receive the assembly reaction force. As a result, the grip of the E-ring can be stably maintained even when subjected to the assembly reaction force.

[0041] As described above, according to this embodiment, the influence of the finger portion's gripping on the deformation of the E-ring during ring assembly is reduced, and the fingertip shape allows the finger portion to withstand the reaction force during E-ring assembly. Therefore, it is possible to grip the E-ring with the finger portions 311 and 312 and assemble it in that position. Thus, even if a dedicated jig cannot access the space for assembling the E-ring, the E-ring can be gripped and assembled by the finger portions, thereby improving the versatility of E-ring assembly. Furthermore, this embodiment is not limited to E-rings but can also be applied to retaining rings with the same assembly method as E-rings, such as U-shaped retaining rings.

[0042] (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.

[0043] In the first embodiment described above, the E-ring was assembled using two fingers, but depending on the E-ring assembly situation, the E-ring may be grasped and assembled using three fingers. Figure 13 shows the fingers of the robot hand 300 in this embodiment. For the sake of explanation, the hand base 301 is not shown. From Figure 13, a finger 313 is positioned relative to the fingers 311 and 312 so as to be movable in direction S3, allowing it to approach or separate from them. As shown in Figure 12, when the E-ring is brought into contact with the shaft, the finger 313 contacts the shaft from the side opposite to where the fingers 312 and 313 are positioned. The E-ring is then assembled by operating the finger 311, 312, and 313 to sandwich the E-ring and the shaft. That is, the E-ring is assembled by bringing the fingers 311, 312, and 313 closer together. The finger portion 313 is sometimes referred to as the third finger portion.

[0044] As described above, according to this embodiment, the influence of the finger portion's gripping on the deformation of the E-ring during ring assembly is reduced, and the fingertip shape allows the finger portion to withstand the reaction force during E-ring assembly, making it possible to grip the E-ring with the finger portions 311 and 312 and assemble it in that position. Therefore, even if a dedicated jig cannot access the space for assembling the E-ring, the finger portion can grip and assemble the E-ring, thus improving the versatility of E-ring assembly. In addition, the finger portion 313 supports the shaft, reducing the Z-direction displacement of the groove due to shaft deflection caused by E-ring assembly. Note that the finger portion 313 is preferably slightly smaller in outer diameter than the finger portions 311 and 312 because it fits into a narrow space, but this is not a requirement. Also, if the shaft deflection is small and space can be secured to access the E-ring, the finger portion 313 may be positioned on the side that receives the reaction force during E-ring assembly, as shown in Figure 14. This reduces the likelihood of the E-ring shifting relative to the finger portions 312 and 313. Furthermore, the various embodiments and modifications described above may be combined.

[0045] (Third embodiment) Next, the 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 first embodiment.

[0046] In the above embodiment, the gripping surfaces 321 connecting ends 351 and 361, and 322 connecting ends 352 and 362 are arc-shaped, but are not limited to this. Various shapes can be used as long as angle a is smaller than angle b. Figure 15 shows the shapes of the finger portions 311 and 312 in this embodiment. For example, as shown in Figure 15(a), the gripping surfaces 321 and 322 may be polygonal rectangular shapes. Also, as shown in Figure 15(b), the finger portions 311 and 312 may be rectangular, and the gripping surfaces 321 and 322 may be polygonal rectangular shapes. Furthermore, the shapes of the gripping surfaces 321 and 322 may be a combination of arc shapes and rectangular shapes.

[0047] As described above, this embodiment reduces the influence of the finger gripping on the deformation of the E-ring during E-ring assembly, and the fingertip shape is such that the finger grip can withstand the reaction force during E-ring assembly. Therefore, it is possible to grip the E-ring with the finger parts 311 and 312 and assemble it in the same manner. Thus, even if a dedicated jig cannot access the space for assembling the E-ring, the E-ring can be gripped and assembled by the finger parts, thereby improving the versatility of E-ring assembly. Furthermore, the various embodiments and modifications described above may be combined and implemented.

[0048] (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 explanation will focus on the differences from the first embodiment.

[0049] Figure 16 shows the shapes of the finger portions 311 and 312 in this embodiment. In this embodiment, the gripping surfaces 321 connecting the ends 351 and 361, and the gripping surfaces 322 connecting the ends 352 and 362, etc., described above are not provided, and the finger portions are circular in shape. When gripping the E-ring with the finger portions 311 and 312, the contact points between the finger portion 311 and the E-ring, and the contact points between the finger portion 312 and the E-ring, are positioned on the opposite side of direction S3 from the center C of the E-ring. That is, the E-ring is gripped in a direction opposite to the assembly direction from the center C of the E-ring, and the finger portions 311 and 312 are gripped in such a way that they receive the assembly reaction force generated when assembling the E-ring at their respective contact points with the E-ring. If the rigidity of the E-ring is low, the end portions may not be used, and the assembly may be performed by holding it with the outer diameter portions of the finger portions 311 and 312. Although the finger shape is shown as circular in Figure 16, it can also be rectangular.

[0050] As described above, this embodiment reduces the influence of the finger grip on the deformation of the E-ring during E-ring assembly, and provides a gripping method that allows the finger grip to withstand the reaction force during E-ring assembly. Therefore, it is possible to grip the E-ring with the finger parts 311 and 312 and assemble it in the same manner. Thus, even if a dedicated jig cannot access the space for assembling the E-ring, the E-ring can be gripped and assembled by the finger parts, thereby improving the versatility of E-ring assembly. Furthermore, the various embodiments and modifications described above may be combined and implemented.

[0051] (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.

[0052] 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.

[0053] Furthermore, while the various embodiments described above have explained the case where the robot arm 200 is a multi-joint robot arm having multiple joints, the number of joints is not limited to this. Although a vertical multi-axis configuration was shown as the type of robot arm, the same configuration can be implemented with different types of joints, such as horizontal multi-joint, parallel link, and Cartesian robots.

[0054] 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.

[0055] 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.

[0056] Furthermore, the disclosure of this embodiment includes the following items.

[0057] (Item 1) A robot hand having a first finger portion and a second finger portion that grip a workpiece by moving closer to or further apart from each other, Each of the first and second finger portions is provided with at least two ends that contact the workpiece. In the direction of approach or separation between the first finger portion and the second finger portion, the end portion on the side opposite to the workpiece assembly direction is located closer to the center than the end portion on the workpiece assembly direction side, with respect to the center, with respect to the center. A robotic hand characterized by the following features.

[0058] (Item 2) In the robot hand described in item 1, In the direction of approach or separation between the first finger portion and the second finger portion, the end portion on the side opposite to the assembly direction of the workpiece with respect to the center and the end portion on the side in the assembly direction of the workpiece with respect to the center are located closer to the center than the furthest part of the first finger portion or the second finger portion from the center. A robotic hand characterized by the following features.

[0059] (Item 3) In the robot hand described in item 1 or 2, In the assembly direction of the workpiece, the midpoint between the end on the side opposite to the assembly direction of the workpiece with respect to the center and the end on the side of the workpiece in the assembly direction with respect to the center is located on the side opposite to the assembly direction of the workpiece with respect to the center. A robotic hand characterized by the following features.

[0060] (Item 4) In a robot hand described in any one of items 1 to 3, The first angle formed by a first line segment passing through the center and in a direction parallel to the approach or separation direction of the first and second finger portions, and a second line segment connecting the center and the end portion positioned on the first finger portion on the side of the workpiece assembly direction with respect to the center, is smaller than the second angle formed by the first line segment and a third line segment connecting the center and the end portion positioned on the first finger portion on the side opposite to the workpiece assembly direction with respect to the center. A robotic hand characterized by the following features.

[0061] (Item 5) In a robot hand described in any one of items 1 to 4, When the aforementioned workpiece is brought into contact with another workpiece, the first and second finger portions have relief portions to avoid interference between the other workpiece and the first and second finger portions. A robotic hand characterized by the following features.

[0062] (Item 6) In a robot hand described in any one of items 1 to 5, The first finger portion includes a first surface that connects at least two of the ends provided on the first finger portion, The second finger portion includes a second surface that connects at least two of the ends provided on the second finger portion. A robotic hand characterized by the following features.

[0063] (Item 7) In the robot hand described in item 6, The first finger portion has a third surface, which is different from the first surface, that supports the workpiece. The second finger portion has a fourth surface, which is different from the second surface, that supports the workpiece. A robotic hand characterized by the following features.

[0064] (Item 8) In the robot hand described in item 7, The third surface has a length less than or equal to the thickness of the workpiece, extending from the first surface. The fourth surface has a length less than or equal to the thickness of the workpiece, extending from the second surface. A robotic hand characterized by the following features.

[0065] (Item 9) In the robot hand described in item 7 or 8, The first and second surfaces are gripping surfaces for gripping the workpiece, and the third and fourth surfaces are support surfaces for supporting the workpiece while it is being gripped. A robotic hand characterized by the following features.

[0066] (Item 10) In a robot hand described in any one of items 6 to 9, The first and second surfaces include at least one shape, such as an arc shape or a rectangular shape. A robotic hand characterized by the following features.

[0067] (Item 11) In a robot hand described in any one of items 1 through 10, The at least two ends include an end that receives a force generated by the deformation of the workpiece and an end that receives a force generated when assembling the workpiece. A robotic hand characterized by the following features.

[0068] (Item 12) In a robot hand described in any one of items 1 through 11, When the workpiece is gripped by the first and second finger portions and the workpiece is brought into contact with another workpiece, the device is provided with a third finger portion that contacts the other workpiece. A robotic hand characterized by the following features.

[0069] (Item 13) In a robot hand described in any one of items 1 through 11, When the workpiece is gripped by the first and second finger portions and the workpiece is brought into contact with another workpiece, the device is provided with a third finger portion that contacts the workpiece. A robotic hand characterized by the following features.

[0070] (Item 14) In a robot hand described in any one of items 1 through 13, The workpiece includes at least one E-ring and a U-shaped retaining ring. A robotic hand characterized by the following features.

[0071] (Item 15) A robot hand having a first finger portion and a second finger portion that grip a workpiece by moving closer to or further apart from each other, The contact portion where the first finger portion contacts the workpiece and the contact portion where the second finger portion contacts the workpiece are located on the opposite side of the assembly direction of the workpiece, with respect to the center of the workpiece. A robotic hand characterized by the following features.

[0072] (Item 16) A robotic system comprising a robotic hand and a robotic arm as described in any one of items 1 through 15.

[0073] (Item 17) A method for manufacturing articles, characterized by manufacturing articles using the robotic system described in item 16.

[0074] (Item 18) A control method for a robot hand having a first finger portion and a second finger portion that grip a workpiece by moving closer to or further apart from each other, Each of the first and second finger portions is provided with at least two ends that contact the workpiece. In the direction of approach or separation between the first finger portion and the second finger portion, with respect to the center of the arc passing through at least three of the ends, the end portion on the side opposite to the workpiece assembly direction is located closer to the center than the end portion on the workpiece assembly direction side with respect to the center. The workpiece is gripped using the first finger portion and the second finger portion. A control method characterized by the following:

[0075] (Item 19) A control method for a robot hand having a first finger portion and a second finger portion that grip a workpiece by moving closer to or further apart from each other, The contact portion where the first finger portion and the workpiece come into contact, and the contact portion where the second finger portion and the workpiece come into contact, are located on the opposite side of the assembly direction of the workpiece, with respect to the center of the workpiece. The workpiece is gripped using the first finger portion and the second finger portion. A robotic hand characterized by the following features.

[0076] (Item 20) A control program capable of executing the control methods described in item 18 or 19.

[0077] (Item 21) A computer-readable recording medium containing the control program described in item 20. [Explanation of symbols]

[0078] 61, 62 Notched surface 71, 72, 81, 82 Work end 200 robotic arms Links 201, 202, 203, 204, 205, 206 210 base 300 Robot Hands 301 Hand base 302 Finger motor 303 Hand control circuit 311, 312, 313 fingers 321, 322 gripping surface 331, 332 Support surface 341, 342 Escape Team 351, 352, 361, 362 End 500 Control Device 600 External Input Device

Claims

1. A robot hand having a first finger portion and a second finger portion that grip a workpiece by moving closer to or further apart from each other, Each of the first and second finger portions is provided with at least two ends that come into contact with the workpiece. In the direction of approach or separation between the first finger portion and the second finger portion, the end portion on the side opposite to the workpiece assembly direction is located closer to the center than the end portion on the workpiece assembly direction side, with respect to the center, with respect to the center. A robotic hand characterized by the following features.

2. In the robot hand according to claim 1, In the direction of approach or separation between the first finger portion and the second finger portion, the end portion on the side opposite to the assembly direction of the workpiece with respect to the center and the end portion on the side in the assembly direction of the workpiece with respect to the center are located closer to the center than the furthest part of the first finger portion or the second finger portion from the center. A robotic hand characterized by the following features.

3. In the robot hand according to claim 1, In the assembly direction of the workpiece, the midpoint between the end on the side opposite to the assembly direction of the workpiece with respect to the center and the end on the side of the workpiece in the assembly direction with respect to the center is located on the side opposite to the assembly direction of the workpiece with respect to the center. A robotic hand characterized by the following features.

4. In the robot hand according to claim 1, The first angle formed by a first line segment passing through the center and in a direction parallel to the approach or separation direction of the first and second finger portions, and a second line segment connecting the center and the end portion positioned on the first finger portion on the side of the workpiece assembly direction with respect to the center, is smaller than the second angle formed by the first line segment and a third line segment connecting the center and the end portion positioned on the first finger portion on the side opposite to the workpiece assembly direction with respect to the center. A robotic hand characterized by the following features.

5. In the robot hand according to claim 1, When the aforementioned workpiece is brought into contact with another workpiece, the first and second finger portions have relief portions to avoid interference between the other workpiece and the first and second finger portions. A robotic hand characterized by the following features.

6. In the robot hand according to claim 1, The first finger portion includes a first surface that connects at least two of the ends provided on the first finger portion, The second finger portion includes a second surface that connects at least two of the ends provided on the second finger portion. A robotic hand characterized by the following features.

7. In the robot hand according to claim 6, The first finger portion has a third surface, which is different from the first surface, that supports the workpiece. The second finger portion has a fourth surface, which is different from the second surface, that supports the workpiece. A robotic hand characterized by the following features.

8. In the robot hand according to claim 7, The third surface has a length less than or equal to the thickness of the workpiece, extending from the first surface. The fourth surface has a length from the second surface that is less than or equal to the thickness of the workpiece. A robotic hand characterized by the following features.

9. In the robot hand according to claim 7, The first and second surfaces are gripping surfaces for gripping the workpiece, and the third and fourth surfaces are support surfaces for supporting the workpiece in a gripped state. A robotic hand characterized by the following features.

10. In the robot hand according to claim 6, The first surface and the second surface include at least one shape, such as an arc shape or a rectangular shape. A robotic hand characterized by the following features.

11. In the robot hand according to claim 1, The at least two ends include an end that receives a force generated by the deformation of the workpiece and an end that receives a force generated when assembling the workpiece. A robotic hand characterized by the following features.

12. In the robot hand according to claim 1, When the workpiece is gripped by the first and second finger portions and the workpiece is brought into contact with another workpiece, the device is provided with a third finger portion that contacts the other workpiece. A robotic hand characterized by the following features.

13. In the robot hand according to claim 1, When the workpiece is gripped by the first and second finger portions and the workpiece is brought into contact with another workpiece, the device is provided with a third finger portion that contacts the workpiece. A robotic hand characterized by the following features.

14. In the robot hand according to claim 1, The workpiece includes at least one E-ring and a U-shaped retaining ring. A robotic hand characterized by the following features.

15. A robot hand having a first finger portion and a second finger portion that grip a workpiece by moving closer to or further apart from each other, The contact portion where the first finger portion and the workpiece come into contact, and the contact portion where the second finger portion and the workpiece come into contact, are located on the opposite side of the assembly direction of the workpiece, with respect to the center of the workpiece. A robotic hand characterized by the following features.

16. A robotic system comprising a robotic hand and a robotic arm according to any one of claims 1 to 15.

17. A method for manufacturing an article, characterized by manufacturing the article using the robot system described in claim 16.

18. A control method for a robot hand having a first finger portion and a second finger portion that grip a workpiece by moving closer to or further apart from each other, Each of the first and second finger portions is provided with at least two ends that come into contact with the workpiece. In the direction of approach or separation between the first finger portion and the second finger portion, with respect to the center of the arc passing through at least three of the ends, the end on the side opposite to the workpiece assembly direction is located closer to the center than the end on the workpiece assembly direction side with respect to the center. The workpiece is gripped using the first finger portion and the second finger portion. A control method characterized by the following:

19. A control method for a robot hand having a first finger portion and a second finger portion that grip a workpiece by moving closer to or further apart from each other, The contact portion where the first finger portion and the workpiece come into contact, and the contact portion where the second finger portion and the workpiece come into contact, are located on the opposite side of the assembly direction of the workpiece, with respect to the center of the workpiece. The workpiece is gripped using the first finger portion and the second finger portion. A robotic hand characterized by the following features.

20. A control program capable of executing the control method described in claim 18 or 19.

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

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