Hand including holding mechanism and component supply system including the same

Abstract

To provide a hand which enables calibration to be performed with a holding mechanism attached to a tip of a robot and eliminates a need to make corrections while picking up a workpiece, and to provide a component supply system.SOLUTION: A hand 6 is attached to a tip of an arm 10 of a robot 4 and picks up a workpiece W. The hand 6 includes a holding mechanism 22 which moves in an open direction in which the holding mechanism 22 holds the workpiece W and in a closed direction in which the holding mechanism 22 releases the workpiece W. The holding mechanism 22 has a plurality of claw parts 24. The holding mechanism 22 opens to hold the workpiece W with the claw parts 24. The claw part 24 is provided with a cutout 26 in which a calibration jig 30 is fixedly positioned.SELECTED DRAWING: Figure 7B

Description

[Technical Field]

[0001] The present invention relates to a gripping mechanism for a hand that grips a workpiece such as a mechanical part or an electronic part, and to a part supply system equipped with the same. [Background technology]

[0002] As a component supply system for workpieces such as mechanical components and electronic components, there is a system in which the workpieces are automatically aligned and supplied to a conveyor table, and then the workpieces are picked up on the conveyor table by a robot and supplied to the next process (for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6-238584 [Patent Document 2] Patent No. 6892952 Summary of the Invention [Problem to be solved by the invention]

[0004] In the component supply system shown in Patent Document 1, a camera installed upstream of a conveyor table captures an image of a workpiece, and the position and orientation of the workpiece are detected using image processing or other methods, after which a robot installed downstream picks up the workpiece. That is, an image plane including the workpiece captured by the camera in the imaging area is transported downstream to a pickup area at a constant speed by the conveyor table. The conveyor table acquires the transport distance and transmits it to a control device. The transport distance is calculated, for example, from the encoder value of the motor installed on the conveyor table.

[0005] From the transport distance obtained from the transport table and the workpiece position within the image plane obtained from the camera, the control device calculates the drive positions of each joint at which the robot picks up the workpiece, and operates the robot to pick up the workpiece. Here, because the imaging area where the camera captures the image plane containing the workpiece and the pickup area where the robot picks up the workpiece are separated, calibration is required to determine the positional relationship between the transport table and the robot, and calibration to determine the positional relationship between the camera, robot, and transport table.

[0006] In the parts supply system shown in Patent Document 2, the conveyor is a disk, and the image plane captured by the camera in the imaging area moves in an arc around the center of the disk. Therefore, if the calibration is not accurate, there is a risk that the robot's pick-up position in the pickup area will be significantly off.

[0007] Previously, when calibrating a robot and conveyor to a camera, if the gripping mechanism that grips the workpiece was attached to the tip of the robot, the center position of the gripping mechanism had to be estimated and set. In this case, it was difficult to determine the exact center position, which resulted in deviations, and the deviations had to be corrected while picking up the workpiece.

[0008] Furthermore, when the gripping mechanism is removed from the tip of the robot and a calibration jig is attached to the tip of the robot to perform calibration, misalignment occurs due to installation errors when the gripping mechanism is reattached, and it is necessary to correct the misalignment while picking up the workpiece.

[0009] An object of the present invention is to provide a hand and a parts supply system that can perform calibration while the gripping mechanism is attached to the tip of the robot and that does not require adjustment while picking up a workpiece. [Means for solving the problem]

[0010] The hand of the present invention is a hand that is attached to the tip of a robot arm and picks up a workpiece, and is equipped with a gripping mechanism that moves in an opening direction to grip the workpiece and in a closing direction to release the workpiece, the gripping mechanism having multiple claw portions, and the gripping mechanism opens to grip the workpiece with the claw portions, and the claw portions are provided with notches in which a calibration jig can be positioned and fixed.

[0011] According to this configuration, a notch for fixing the position of the calibration jig is provided in the jaws, and the position and orientation of the calibration jig relative to the robot are fixed by opening the gripping mechanism and applying an outward force. This makes it possible to clarify the center position of the gripping mechanism that grips the workpiece without changing it during calibration. This makes calibration easier. Furthermore, since calibration can be performed with the gripping mechanism and jaws installed, there is no need to correct any misalignment after calibration.

[0012] In the present invention, the calibration jig may have a base portion fixed to the claw portion and a pin portion extending from the base portion to a side opposite the gripping mechanism, and the base portion of the calibration jig may have a convex portion protruding inward, and the notches in the claw portion may have a shape that matches the convex portion of the base. With this configuration, the position and orientation of the calibration jig are more likely to match the notches than when the notches are arc-shaped, and the position and orientation of the calibration jig are more likely to be fixed.

[0013] In the present invention, the tip of the pin of the calibration jig may be shaped like a cross. With this configuration, not only the center position of the gripping mechanism but also its position in the rotational direction becomes clear, making calibration even easier.

[0014] In the present invention, the calibration jig and the claws may be provided with a jig insertion hole and a claw insertion hole, respectively, that are coaxial when the claws grip the calibration jig. With this configuration, by inserting positioning pins into the jig insertion hole and the claw insertion hole, it is possible to prevent the calibration jig from shifting in the central axis direction of the gripping mechanism, thereby making calibration even easier.

[0015] In the present invention, the hand may further include an actuator with one or more degrees of freedom for changing the posture of the gripping mechanism. With this configuration, even if the central axis of the tip of the robot and the central axis of the gripping mechanism do not coincide, the center position of the gripping mechanism can be clearly determined by the calibration jig, making calibration easy.

[0016] The component supply system of the present invention includes a component supply device that supplies a workpiece to a transport table, a robot that transports the workpiece from a first area where the transport table is located to a second area different from the first area, and a hand attached to the end of the robot's arm that picks up the workpiece on the transport table in the first area and places the workpiece in the second area. The hand has a gripping mechanism that moves in an open direction to grip the workpiece and a close direction to release the workpiece. The gripping mechanism has multiple claws that grip the workpiece with the claws when the gripping mechanism is opened. The claws have notches that fix the position of a calibration jig, and when the gripping mechanism is opened and an outward force is applied, the position and orientation of the calibration jig relative to the robot are fixed. [Effects of the Invention]

[0017] According to the hand and part supply system of the present invention, when calibration is performed while the gripping mechanism that grips the workpiece is attached to the tip of the robot, the center position of the gripping mechanism can be clearly determined by installing a calibration jig in place. This eliminates the need to correct misalignment while picking up the workpiece. Furthermore, since there is no need to remove the gripping mechanism from the tip of the robot, there is no need to attach a dedicated calibration jig to the tip of the robot to be used after removing the gripping mechanism to perform calibration. Therefore, since there is no misalignment due to attachment error of the gripping mechanism, there is no need to correct the misalignment while picking up the workpiece. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a perspective view showing a component supply system including a hand according to a first embodiment of the present invention. [Figure 2] FIG. 10 is a perspective view showing a modified example of the component supply system. [Figure 3] FIG. 10 is a perspective view showing another modified example of the component supply system. [Figure 4] FIG. [Figure 5] 5 is a view of the hand of FIG. 4 as seen from the arrow V. FIG. [Figure 6A] FIG. 10 is a plan view showing an example of a calibration jig. [Figure 6B] 6B is a cross-sectional view of the calibration jig taken along line VIB-VIB in FIG. 6A. [Figure 6C] FIG. 6C is a view of the calibration jig in FIG. 6B as seen from the arrow VIC. [Figure 7A] FIG. 10 is a diagram showing the state in which the calibration jig is held by the hand. [Figure 7B] FIG. 7B is a cross-sectional view taken along line VIIB-VIIB in FIG. 7A. [Figure 8A] FIG. 10 is a plan view showing a hand according to a second embodiment of the present invention. [Figure 8B] FIG. 8B is a cross-sectional view taken along line VIIIB-VIIIB in FIG. 8A. [Figure 9A] FIG. 2 is a plan view showing a calibration jig held by the hand. [Figure 9B] 9B is a cross-sectional view of the calibration jig taken along line IXB-IXB in FIG. 9A. [Figure 9C] 9C is a cross-sectional view of the calibration jig taken along line IXC-IXC of FIG. 9A. [Figure 10A] FIG. 10 is a plan view showing a modified example of the calibration jig. [Figure 10B] 10B is a cross-sectional view of the calibration jig of FIG. 10A taken along XB-XB. [Figure 11A] FIG. 10 is a plan view showing a state in which a calibration jig according to a modified example is fixed to a hand. [Figure 11B] FIG. 11B is a cross-sectional view taken along line XIB-XIB in FIG. 11A. [Figure 12A] FIG. 10 is a diagram showing another modified example of the calibration jig. [Figure 12B] 12B is a view of the calibration jig of FIG. 12A as viewed in the direction of arrow XIIB. [Figure 13A] FIG. 10 is a plan view showing a state in which a hand according to a third embodiment of the present invention grips a workpiece. [Figure 13B] FIG. 13 is a side view of the hand as seen from the direction of arrow XIIIB. [Figure 13C] FIG. 13B is an enlarged plan view showing a portion XIIIC of FIG. 13A in an enlarged manner. [Figure 14A] FIG. 10 is a plan view showing a state in which the hand is gripping a calibration jig. [Figure 14B] FIG. 14B is a cross-sectional view taken along line XIVB-XIVB in FIG. 14A. [Figure 14C] FIG. 14B is an enlarged view of the XIVC portion of FIG. 14A. [Figure 15] FIG. 10 is a cross-sectional view showing a state in which a hand according to a fourth embodiment of the present invention grips a workpiece. [Figure 16A] FIG. 2 is a plan view showing the hand and the calibration jig. [Figure 16B] FIG. 16B is a cross-sectional view taken along line XIVB-XIVB in FIG. 16A. [Figure 17A] FIG. 2 is a plan view showing the calibration jig. [Figure 17B] 17B is a side view of the calibration jig of FIG. 17A as viewed from the direction of arrow XVIIB. [Figure 18] FIG. 10 is a diagram showing a robot equipped with a hand according to a fifth embodiment of the present invention. [Figure 19] FIG. [Figure 20] FIG. 20 is a diagram showing a different posture of the hand from that shown in FIG. 19. [Figure 21A] FIG. 2 is a cross-sectional view showing a state in which the hand is gripping a workpiece. [Figure 21B] 21B is a plan view of the state of FIG. 21A as seen from the direction of arrow XXIB. [Figure 22] FIG. 10 is a perspective view showing a component supply system according to a sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] Preferred embodiments of the present invention will now be described with reference to the drawings. In the following description, "upstream" and "downstream" refer to "upstream" and "downstream" in the direction of work flow. Fig. 1 is a perspective view showing a component supply system SY according to a first embodiment of the present invention, Fig. 2 is a perspective view showing a modified version of the component supply system SY, and Fig. 3 is a perspective view showing another modified version of the component supply system SY.

[0020] [First embodiment] [System Wide] 1, the parts supply system SY uses a robot 4 and a hand 6 to pick up workpieces W that have been automatically aligned by a parts supply device 2 and supply them to an automatic machine or the like for the next process. In detail, the parts supply system SY includes the parts supply device 2 that supplies the workpieces W to a transport table 8, a robot 4 that transports the workpieces W from a first area A1 where the transport table 8 is located to a second area A2 that is different from the first area A1, and a hand 6 attached to the tip of an arm 10 of the robot 4.

[0021] In this embodiment, the workpiece W is an annular member such as the outer ring of a bearing. However, the workpiece W may be any hollow object, such as a mechanical part, an electronic part, a plastic part, a drug, a medical product, a food product, or a miscellaneous item.

[0022] The component supply device 2, robot 4, and hand 6 are synchronously controlled by a control device 12. Specifically, the position and posture of the workpiece W on the transport table 8 is detected by a workpiece detection means 14, the arm 10 of the robot 4 moves to the position detected by the workpiece detection means 14, and the hand 6 grasps the workpiece W at an angle corresponding to the posture detected by the workpiece detection means 14. Thereafter, the arm 10 of the robot 4 moves to a second area A2, and the hand 6 releases the workpiece W. This operation is repeated thereafter. Note that the control device 12 is omitted from Figures 2, 3, 18, and 22, which will be described later.

[0023] In this embodiment, the workpiece detection means 14 in Fig. 1 is an imaging means such as a camera. However, the workpiece detection means 14 is not limited to a camera and may be, for example, a distance sensor. The camera may be provided exclusively for detecting the position and orientation of the workpiece W, or may be used for other purposes. The camera may also be fixed, or may be attached to the arm 10 of the robot 4.

[0024] [Parts supply device] A sensing area 16 and a pickup area 18 are provided on the transport table 8 of the component supply device 2. In the sensing area 16, the position and posture of the workpiece W are detected by the workpiece detection means 14 described above. In the pickup area 18, the workpiece W is picked up by the robot 4 and hand 6.

[0025] In this example, the sensing area 16 and the pickup area 18 overlap partially or entirely. In detail, the workpieces W are placed loosely on a table or in a box, and an image of the sensing area 16 is obtained by a camera (workpiece detection means) 14 installed above, and the position and orientation of the workpieces W are obtained by image processing. Based on the obtained information on the position and orientation of the workpieces W, the robot 4 picks up the target workpieces W.

[0026] At this time, calibration must be performed to align the reference coordinate system of the robot 4 with the coordinate system of the image plane IP captured by the camera 14 in advance. The calibration method involves pointing at an arbitrary position within the image plane IP with the tip of a tool attached to the tip of the robot 4, and calculating using the position of the tool tip in the reference coordinate system of the robot 4. Alternatively, the robot 4 is stopped in a position where part of the robot 4 or part of the tool is captured within the imaging range of the camera 14, and calculation is performed by image processing using feature points as references.

[0027] In the modified example shown in Fig. 2, the component supply device 2 is a linear conveyor 8, and the workpiece W flows on its upper surface. In the example of Fig. 2, the sensing area 16 where the camera 14 captures an image of the workpiece W and the pickup area 18 where the robot 4 picks up the workpiece W do not overlap.

[0028] In the example of Figure 2, the workpiece W flows on the conveyor 8, and position and orientation information is obtained by the camera 14 in the sensing area 16. When the workpiece W flows to the pickup area 18, the position of the target workpiece W is calculated from the conveying distance D of the conveyor 8, and converted into the reference coordinate system of the robot 4, which then allows the robot 4 to pick up the workpiece W. For this reason, it is necessary to align in advance by calibration the coordinate system of the image plane IP captured by the camera 14 and the reference coordinate system of the robot 4 in the image plane IPa after transport, assuming that the image plane IP has been transported on the conveyor.

[0029] As a calibration method, for example, a calibration plate is prepared and passed from upstream, and an image is taken with a camera 14 in a sensing area 16 to obtain position information of characteristic points, and then the characteristic points are indicated in a pickup area 18 with a dedicated jig attached directly to the tip of the robot 4.

[0030] In the modified example shown in Fig. 3, the component supply device 2 is an arc-shaped disk or conveyor 8. In this case, calibration must be performed in the same manner as in the example of Fig. 2. The calibration issues in the systems of Figs. 1 to 3 will be discussed later.

[0031] [robot] The configuration of robot 4 will be described using Figure 1, but the configuration of robot 4 is the same in Figures 2 and 3. Robot 4 is an articulated robot that has multiple arms 10 that rotate around multiple rotation axes. Robot 4 rotates between a first area A1 where a transfer table 8 is located and a second area A2 for the next process. Robot 4 in this embodiment has a base 20 fixed to the floor surface and three arms, first to third, 10A, 10B, and 10C.

[0032] The base 20 is a cylindrical member with an axis AX1 extending in the vertical direction. The base 20 is connected to the floor surface so as to be rotatable about a first axis of rotation AX1. In this embodiment, the first axis of rotation AX1 coincides with the axis AX1 of the base 20.

[0033] First arm 10A is a rod-like member extending linearly, with base end 10Aa connected to the upper part of base 20 so as to be rotatable about a second horizontal axis of rotation AX2. Second arm 10B is a rod-like member extending linearly, with base end 10Ba connected to tip end 10Ab of first arm 10A so as to be rotatable about a third horizontal axis of rotation AX3. Second arm 10B is rotatable about a fourth horizontal axis of rotation AX4 relative to tip end 10Ab of first arm 10A.

[0034] The third arm 10C is a rod-like member extending linearly, and is connected to the tip 10Bb of the second arm 10B so as to be rotatable about a fifth rotation axis AX5 in the horizontal direction. The third arm 10C is rotatable about a sixth rotation axis AX6 in the vertical direction relative to the tip 10Bb of the second arm 10B. The hand 6 is attached to the lower end 10Ca of the third arm 10C.

[0035] The base 20 and the arms 10A, 10B, and 10C are driven by actuators (not shown). The actuators are, for example, electric motors, but are not limited to this. In this embodiment, the robot 4 is fixed to the floor, but it does not have to be fixed. Furthermore, the robot 4 is not limited to the structure of this embodiment, and any working robot can be applied.

[0036] [hand] The configuration of the hand 6 will be described using Figures 4 and 5. The configuration of the hand 6 is the same in Figures 1 to 3. The hand 6 picks up the workpiece W on the transport table 8 in the first area A1 (Figure 1) and places the workpiece W in the second area A2 (Figure 1). The hand 6 has a gripping mechanism 22 that moves in an open direction to grip the workpiece W and in a closed direction to release the workpiece. Figure 4 shows the hand 6 with the gripping mechanism 22 in an open state. The gripping mechanism 22 is driven by compressed air, for example. However, the drive source of the gripping mechanism 22 is not limited to this and may be a hydraulic motor, an electric motor, or the like.

[0037] The gripping mechanism 22 has a plurality of movable bodies 23 that move in the opening and closing direction. In this embodiment, two movable bodies 23 are provided. Each movable body 23 of the gripping mechanism 22 is provided with a claw portion 24. In this embodiment, one claw portion 24 is provided for each movable body 23, for a total of two claw portions 24, but the number of claw portions 24 is not limited to this. When the gripping mechanism 22 opens (when it moves in the opening direction), the workpiece W is gripped by the claw portions 24.

[0038] As shown in Fig. 5, the claw portion 24 is provided with a notch 26 in which the calibration jig 30 (Fig. 6A) is fixed in position. The notch 26 is formed in the gripping surface 24a of the claw portion 24 that grips the workpiece W, and is a groove recessed in the closing direction from the gripping surface 24a. The shape of the notch 26 in this embodiment is triangular. In other words, the notch 26 in this embodiment is a V-shaped groove. However, the shape of the notch 26 is not limited to this.

[0039] 6A to 6C show an example of the calibration jig 30. As shown in FIG. 6B, the calibration jig 30 has a base 32 fixed to the claws 24, and a pin 34 extending from the base 32 toward the opposite side of the gripping mechanism 22 (downward in FIG. 6B). A tip 34a of the pin 34 has an acute angle so as to point to a feature point during calibration. In this embodiment, the tip 34a of the pin 34 points to the center of the pin 34, i.e., the center X2 of the calibration jig 30.

[0040] In this embodiment, the base 32 of the calibration jig 30 is a box-shaped structure with a bottom that opens upward (toward the gripping mechanism). As shown in FIG. 6A , the base 32 of this embodiment is a rectangular box-shaped structure with its longitudinal direction aligned with the opening and closing direction of the gripping mechanism when viewed from above (toward the gripping mechanism). In detail, the base 32 has a rectangular bottom wall 32a and four side walls 32b extending upward (toward the gripping mechanism) from the bottom wall 32a. The four side walls 32b consist of a pair of side walls 32ba, 32ba extending in the longitudinal direction and a pair of side walls 32bb, 32bb that are perpendicular to the bottom wall 32a. The shape of the base 32 is not limited to this.

[0041] 6B, the pin portion 34 extends downward from the lower surface of the bottom wall 32a. As shown in FIG. 6C, in this embodiment, the center of the base portion 32 and the center of the pin portion 34 coincide with each other. In other words, the center of the base portion 32 coincides with the center X2 of the calibration jig 30.

[0042] As shown in FIG. 6A, a protrusion 35 that protrudes inward (toward the center of the base 32) is formed on the base 32 of the calibration jig 30. One protrusion 35 is provided on each of two side walls 32bb, 32bb that are perpendicular to the opening and closing direction. In this embodiment, the protrusion 35 is formed from the lower end to the upper end of the side wall 32bb. The cross-sectional shape of the protrusion 35 matches the shape of the notch 26 of the claw portion 24, and in this embodiment, is triangular. The shapes of the notch 26 and the protrusion 35 only need to match each other, and may be polygonal other than triangular, or may be circular.

[0043] 7A and 7B show a state in which the calibration jig 30 is gripped by the claws 24. As shown in Fig. 7B, during calibration, the base 32 of the calibration jig 30 is gripped by the gripping surfaces 24a of the claws 24. At this time, the center X1 of the gripping mechanism 22 (hereinafter referred to as "workpiece gripping center X1") coincides with the center X2 of the calibration jig 30.

[0044] As described above, the notches 26 of the claws 24 shown in Fig. 7A have a shape that matches or corresponds to the corners 32a of the base 32. In the example of Fig. 7A, two convex portions 35 on diagonal corners that face each other in the opening and closing direction are fitted into the two notches 26, respectively. With this structure, when a force is applied to the claws 24 in the opening direction, the calibration jig 30 easily fits into the notches 26 of the claws 24, making it easy to install the calibration jig 30.

[0045] By opening the gripping mechanism 22 and applying a force to the outside, the position and posture of the calibration jig 30 relative to the robot 4 are fixed. In detail, by applying a force to the calibration jig 30 from the claws 24 when the gripping mechanism 22 is opened, displacement of the calibration jig 30 when the calibration jig 30 is gripped is suppressed.

[0046] 7B shows a state in which the gripping mechanism 22 is open and the calibration jig 30 is gripped by the claws 24, but by designing the calibration jig 30 so that no force is applied from the claws 24 when the gripping mechanism 22 is closed, the calibration jig 30 can be easily removed or installed. Also, by making the convex portions 35 of the calibration jig 30 longer than the notches 26 of the claws 24, the gripping state is stabilized and displacement is suppressed.

[0047] [Calibration Issues] The conventional hand 6 without the notch 26 in the claw portion 24 has the following problems. In the system SY of Fig. 1, in the case of a structure in which the gripping mechanism 22 is moved in the opening direction as shown in Fig. 4 to grip the workpiece W with the multiple jaws 24, the center position of the gripping mechanism 22 is unclear when the workpiece W is not being gripped, and therefore the calibration position is likely to shift. In other words, in this structure, when there is no workpiece W, there are gaps between the multiple jaws 24, and the center of the gripping mechanism 22 becomes virtual. Also, since the tilt of the workpiece gripping center X1 is unclear, it is necessary to correct the tilt after calibration.

[0048] In the case of the system SY in Fig. 2, after calibration, the dedicated jig is removed from the tip of the robot 4, and the gripping mechanism 22 is reinstalled at the tip of the robot. Therefore, it is necessary to correct any positional or tilt errors that may occur when reinstalling the jig after calibration.

[0049] In the system SY in Figure 3, correction is required after calibration, just as in Figure 2. Furthermore, in the system SY in Figure 3, the paths of the workpiece W and image plane IP are arc-shaped, not straight. Therefore, deviations during calibration or deviations when the dedicated jig is removed and the gripping mechanism is reinstalled at the tip of the robot 4 have a significant impact on the operability during pickup.

[0050] [Action and effect] According to the configuration of the present embodiment described above, as shown in FIGS. 7A and 7B, notches 26 for fixing the position of the calibration jig 30 are provided in the claws 24, and the position and orientation of the calibration jig 30 relative to the robot 4 are fixed by opening the gripping mechanism 22 and applying an outward force. This clarifies the center position (workpiece gripping center X1) of the gripping mechanism 22 without changing the gripping mechanism 22 that grips the workpiece W during calibration. This makes calibration easier. Furthermore, calibration can be performed with the gripping mechanism 22 and the claws 24 in place, eliminating the need for misalignment correction after calibration.

[0051] 7A, the notch 26 of the claw portion 24 has a shape that matches the convex portion 35 of the base portion 36 of the calibration jig 30. This makes it easier for the position and posture of the calibration jig 30 to match the notch 26, and makes it easier to fix the position and posture of the calibration jig 30, compared to when the notch 26 is an arc.

[0052] When performing calibration while the gripping mechanism 22 that grips the workpiece W is still attached to the tip of the robot 4, the central position of the gripping mechanism 22 (workpiece gripping center X1) becomes clear by installing the calibration jig 30 as is. Therefore, there is no need to correct any misalignment while picking up the workpiece W. Also, since there is no need to remove the gripping mechanism 22 from the tip of the robot 4, there is no need to attach a dedicated calibration jig to the tip of the robot 4 to use after removing the gripping mechanism 22 to perform calibration. Therefore, there is no misalignment due to an attachment error of the gripping mechanism 22, so there is no need to correct any misalignment while picking up the workpiece W.

[0053] As described above, according to the gripping mechanism 22 of the hand 6 of the above embodiment, in any of the component supply systems SY shown in FIGS. 1 to 3, misalignment correction after calibration is not required.

[0054] Other embodiments will be described below. In each embodiment, the same components as those in the preceding embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0055] [Second embodiment] 8A and 8B show a hand 6A according to a second embodiment. In the hand 6A according to the second embodiment, each claw 24 is provided with a claw insertion hole 40. In this embodiment, the claw insertion hole 40 is a through hole whose axis extends in a direction perpendicular to the workpiece gripping center X1.

[0056] 9A to 9C show a calibration jig 30A held by a hand 6A of the second embodiment. As shown in FIG. 9B, the calibration jig 30A has a jig insertion hole 42 formed in its base 32. The jig insertion hole 42 is provided at a position corresponding to the claw insertion hole 40. In this embodiment, as shown in FIG. 8B, the axis of the jig insertion hole 42 is set to be coaxial with the claw insertion hole 40 when the jig is held by the claw 24.

[0057] As shown in Fig. 8B, with the gripping mechanism 22 closed, the calibration jig 30A is placed between the two claws 24, 24, and the positioning pin 44 is inserted through the claw insertion hole 40 and the jig insertion hole 42. In this state, the gripping mechanism 22 is opened to fix the calibration jig 30A. At this time, the positioning pin 44 acts as a guide, making it easy to place the calibration jig 30A. The other configurations are the same as those of the first embodiment.

[0058] The second embodiment achieves the same effects as the first embodiment. Furthermore, by inserting the positioning pin 44 into the claw insertion hole 40 and the jig insertion hole 42, it is possible to prevent the calibration jig 30A from shifting in the direction of the central axis (workpiece gripping center) X1 of the gripping mechanism 22. This makes calibration even easier. Furthermore, since the axial position of the calibration jig 30A is uniquely determined, it is also possible to specify the height during calibration. In this case, by providing a slight clearance between the claw insertion hole 40, the jig insertion hole 42, and the positioning pin 44, it is possible to prevent shifting while facilitating installation.

[0059] 10A and 10B show modified examples of the calibration jig. A calibration jig 30B in Fig. 10A has a positioning protrusion 46 provided on its base 32 instead of the jig insertion hole 42. The axis of the positioning protrusion 46, like the axis of the jig insertion hole 42, is set to be coaxial with the claw insertion hole 40 when the calibration jig is gripped by the claws 24. The amount of protrusion of the positioning protrusion 46 is set to a length that allows the calibration jig 30B to be removed from the claws 24 when the gripping mechanism 22 is closed.

[0060] 11A and 11B, with the gripping mechanism 22 closed, the calibration jig 30B is placed between the two claws 24, 24. In this state, by opening the gripping mechanism 22, the positioning protrusion 46 is inserted into the claw insertion hole 40. By further opening the gripping mechanism 22, the calibration jig 30B is fixed. At this time, the positioning protrusion 46 acts as a guide, making it easy to place the calibration jig 30B.

[0061] According to this modification, installation is easier because it eliminates the need to insert the positioning pins 44 into the claw insertion holes 40 and the jig insertion holes 42 while fixing the calibration jig 30A with the gripping mechanism 22 closed as shown in Fig. 8B. The other configurations and effects are the same as those of the second embodiment.

[0062] 12A and 12B show another modified calibration jig 30C. In this example, the tip 34a of the pin 34 is in the shape of a cross. The tip 34a of the pin 34 is a portion that indicates a feature point during calibration. The other configurations are the same as those of the example in FIGS. 10A and 10B.

[0063] This modification produces the same effects as the example in Figures 10A and 10B. Furthermore, according to the modification in Figures 12A and 12B, the tip of the pin portion 34 of the calibration jig 30C has a cross shape, so not only the center position (workpiece gripping center X1) of the gripping mechanism 22 but also its position in the rotational direction is clear. Specifically, by visually checking the circumferential position of the cross, it is possible to grasp how much the gripping mechanism 22 is displaced in the circumferential direction, that is, its position in the rotational direction. This makes calibration even easier.

[0064] The configuration in which the tip portions 34a of the pin portions 34 of the calibration jig 30C in this modified example are cross-shaped can also be applied to the calibration jig 30 in FIGS. 6A to 6C and the calibration jig 30A in FIGS. 9A to 9C.

[0065] [Third embodiment] 13A to 13C and 14A to 14C show a hand 6B according to a third embodiment. As shown in FIGS. 13A and 13B, the hand 6B according to the third embodiment grips a workpiece W such as an O-ring. In this case, as shown in FIG. 13C, the claws 24 can grip the workpiece W more stably by conforming them to the shape of the workpiece W to be gripped. Specifically, the shape of the gripping surfaces 24a of the claws 24 is shaped to fit the inner peripheral surface of the workpiece W.

[0066] 14A and 14B show the state in which the hand 6B of the third embodiment grips the calibration jig 30, i.e., the state in which calibration is being performed. Even in this case, as shown in FIG. 14C, the portions of the base 32 of the calibration jig 30 other than the convex portions 35 do not need to follow the shape of the claws 24. This makes it possible to use one calibration jig 30 for multiple claws 24 with different shapes that match the shape of the workpiece W. The other configurations and effects are the same as those of the first embodiment.

[0067] 13A to 14C, an example has been described in which the calibration jig 30 of Figures 6A to 6C is used, but the calibration jig 30A of Figures 9A to 9C, the calibration jig 30B of Figures 10A and 10B, or the calibration jig 30C of Figures 12A and 12B can also be used. When the calibration jig 30B of Figures 10A and 10B is used, claw insertion holes 40 are provided in the claws 24 of the hand 6B of the third embodiment.

[0068] [Fourth embodiment] 15 to 17C show a hand 6C according to a fourth embodiment. The hand 6C of the fourth embodiment grips a workpiece W having a rounded concave surface Ws on the inside, such as the outer ring of a bearing shown in FIG. 15. In the fourth embodiment, a protrusion 48 that protrudes in the opening direction is formed on the gripping surface 24a of the claws 24. The tip surface of the protrusion 48 has a shape that follows the shape of the concave surface Ws of the workpiece W, and when the gripping mechanism 22 opens outward, the protrusion 48 of the claws 24 comes into contact with the concave surface Ws of the workpiece W, applying a force to the workpiece W in the opening direction and gripping the workpiece W.

[0069] 16A and 16B show a hand 6C according to the fourth embodiment and a corresponding calibration jig 30D. FIGS. 16A and 16B show a state in which the hand 6C is closed, i.e., a state in which the calibration jig 30D is not gripped by the hand 6C. As shown in FIG. 16B, a through-hole 45 is formed in the calibration jig 30D at a position corresponding to the protrusion 48 of the claw portion 24. Specifically, the through-hole 45 is formed in the side walls 32bb, 32bb of the base 32 of the calibration jig 30D that face the opening and closing direction. When the gripping mechanism 22 opens outward, the protrusion 48 of the claw portion 24 is inserted into the through-hole 45 of the calibration jig 30D, and the center position of the gripping mechanism 22 (workpiece gripping center X1) becomes clear.

[0070] 16A and 16B, the claws 24 and the protrusions 48 of the claws 24 do not come into contact with the calibration jig 30D, so the calibration jig 30D can be easily installed and removed.

[0071] 17A and 17B show the calibration jig 30D. The calibration jig 30D of this example is open not only upward as shown in FIG. 17B but also to the side as shown in FIG. 17A. Specifically, the calibration jig 30D of this example has only one side wall 32ba extending in the opening and closing direction of the base 32. In other words, this calibration jig has a structure in which one side wall 32ba is omitted from the calibration jig 30 shown in FIG. 6A. The shape shown in FIGS. 17A and 17B makes it easier to visually confirm that the protrusions 48 of the claw portions 24 are inserted into the through holes 45 of the calibration jig 30D. As a result, installation of the calibration jig 30D becomes even easier.

[0072] [Fifth embodiment] FIG. 20 shows a robot 4A equipped with a hand 6D according to the fifth embodiment.

[0073] [robot] 18 is a horizontal articulated robot having multiple arms 50 that move horizontally. The robot 4A rotates between a first area A1 where a transport table 8 is located and a second area A2 for the next process. The robot 4A of this embodiment has a base 52 fixed to the floor surface and three arms, first to third, 50A, 50B, and 50C.

[0074] The first arm 50A is a square rod-shaped member extending horizontally, with a base end 50Aa connected to the upper surface of the base part 52 so as to be rotatable about a first vertical axis of rotation AX11. The second arm 50B is a square rod-shaped member extending horizontally, with a base end 50Ba connected to a tip end 50Ab of the first arm 50A so as to be rotatable about a second vertical axis of rotation AX12.

[0075] The third arm 50C is a cylindrical shaft member extending vertically and inserted into the tip 50Bb of the second arm 50B. The third arm 50C is movable vertically relative to the tip 50Bb of the second arm 50B and is rotatable about a third vertical axis of rotation AX13. The hand 6D is attached to a lower end 50Ca of the third arm 50C.

[0076] Each of the arms 50A, 50B, and 50C is driven by an actuator (not shown). The actuator is, for example, an electric motor, but is not limited to this. In this embodiment, the robot 4A is fixed to the floor surface, but it does not have to be fixed. Furthermore, the robot 4A is not limited to the structure of this embodiment, and any working robot can be applied.

[0077] [hand] The hand 6D of this embodiment has an actuator 54 with one or more degrees of freedom that changes the posture of the gripping mechanism 22. The hand 6D is attached to the lower end 50Ca of the third arm 50C so as to be rotatable about a third rotation axis AX13. The third arm 50C and the hand 6D of the robot 4A are connected by an L-shaped bracket 52 shown in FIG.

[0078] More specifically, a lower end 50Ca of the third arm 50C is connected to the upper surface of the horizontal portion 52a of the bracket 52, and an actuator 54 of the hand 6D is connected with a bolt to the vertical portion 52b of the bracket 52. In this embodiment, the hand 6D is attached to the inner surface of the vertical portion 52b of the bracket 52, i.e., the surface on the side of the third rotation axis AX13. However, the shape of the bracket 52 and the arrangement of the hand 6D are not limited to this.

[0079] The actuator 54 has a fourth rotation axis AX14 extending horizontally. The gripping mechanism 22 is connected to the actuator 54 via a connecting member 56. The connecting member 56 is made of a long, plate-shaped member, and a base end 56a thereof is connected to the actuator 54 so as to be rotatable about the fourth rotation axis AX14, and a tip end 56b thereof is connected to the gripping mechanism 22 by a bolt. When the actuator 54 is driven, the gripping mechanism 22 assumes the position shown in FIG. 20.

[0080] FIG. 20 shows a state in which the actuator 54 has been rotated 90° from FIG. 19, i.e., the hand 6D is facing downward. On the other hand, FIG. 19 shows a state in which the hand 6D is facing sideways. In this way, the hand 6D can be moved to any position by rotating the bracket 52 about the third rotation axis AX13, and the gripping mechanism 22 can be moved to any posture by rotating the connecting member 54 about the fourth rotation axis AX14. In this way, because the posture of the hand 6D can be changed, it is possible to prevent the hand 6D from coming into contact with other workpieces or equipment when picking up the workpiece W. As a result, malfunctions in the hand 6D or other equipment can be prevented, and work efficiency is improved.

[0081] Similar to the above-described embodiments, the gripping mechanism 22 of this embodiment is a chuck device having a plurality of jaws 24 that can be opened and closed. In this embodiment, the gripping mechanism 22 has two jaws 24, but the number of jaws 24 may be three or more. As shown in FIG. 20 , in this embodiment, the third rotation axis AX13 of the third arm 50C of the robot 4A does not coincide with the workpiece gripping center X1 of the gripping mechanism 22. In other words, the workpiece gripping center X1 is offset horizontally from the third rotation axis AX13.

[0082] In the fifth embodiment, an actuator 54 with one or more degrees of freedom is installed at the tip of the robot 4A, and after picking up the workpiece W, it changes the posture of the workpiece W and places the workpiece W in a predetermined location. If the rotation axis AX14 of the actuator 54 with one or more degrees of freedom does not intersect with the rotation axis AX13 of the joint at the tip of the robot 4A but is offset from it, or if the bracket 52 is L-shaped, the position where the robot 4A picks up the workpiece will be significantly off unless consideration is given to the offset between the rotation axis AX13 of the robot 4A and the gripping center (workpiece gripping center) X1 of the gripping mechanism 22.

[0083] As described in the first embodiment, by providing the notches 26 in the claws 24 of the hand 6D of the fifth embodiment, it is possible to align the central axis of the calibration jig 30 with the central axis (workpiece gripping center) X1 of the gripping mechanism 22. Therefore, as shown in Figures 21A and 21B, even if the central axis AX13 of the tip of the robot does not coincide with the workpiece gripping center X1 in the posture for gripping the workpiece W, calibration can be performed without considering the offset amount.

[0084] According to the fifth embodiment, even if the central axis AX13 of the tip of the robot 4A does not coincide with the central axis X1 (workpiece gripping center) of the gripping mechanism 22, the calibration jig 30 clarifies the central position of the gripping mechanism 22, making calibration easy.

[0085] [Sixth embodiment] Fig. 22 shows a component supply system SY according to a sixth embodiment. The component supply system SY of the sixth embodiment includes a component supply device 2 having a disk-shaped transport unit as shown in Fig. 3, and a robot 4A and a hand 6D of the fifth embodiment as shown in Figs. 18 to 21A and 21B.

[0086] As described above, in the component supply device 2 whose transport unit is disk-shaped, the influence of deviations during calibration and deviations when the gripping mechanism 22 is reinstalled at the tip of the robot 4A after the dedicated jig is removed is significant. Also, in the hand 6D having the L-shaped bracket 52 and the actuator 54, the central axis AX13 of the tip of the robot 4A and the central axis (workpiece gripping center) X1 of the gripping mechanism 22 do not coincide, making calibration difficult.

[0087] 21A and 21B, by providing a notch 26 in the claw portion 24, the central axis of the calibration jig 30 and the central axis (workpiece gripping center) X1 of the gripping mechanism 22 can be aligned, making the gripping center position clear. This makes calibration easier. In this way, even when using a component supply device 2 having a disk-shaped transport unit and a hand 6D having an L-shaped bracket 52 and an actuator 54, calibration can be performed while the gripping mechanism 22 is attached to the tip of the robot 4A, and adjustments while picking up the workpiece W are not required.

[0088] The present invention is not limited to the above-described embodiments, and various additions, modifications, and omissions are possible without departing from the spirit of the present invention. Therefore, such additions, modifications, and omissions are also included in the scope of the present invention. [Explanation of symbols]

[0089] 2 Parts supply device 4,4A Robot 6,6A,6B,6C,6D Hand 8 Transport Platform 10 Arm 22 Gripping mechanism 24 Claw 26 Notch 30, 30A, 30B, 30C, 30D Calibration Jig 32 Base 34 Pin section 35 Convex part 40 Claw insertion hole 42 Jig insertion hole 48 Protrusion 54 Actuator SY Parts Supply System double work

Claims

1. A hand attached to the tip of a robot arm to pick up a workpiece, a gripping mechanism that moves in an opening direction to grip the workpiece and in a closing direction to release the workpiece; The gripping mechanism has a plurality of claws, and when the gripping mechanism opens, the workpiece is gripped by the claws. The hand has a notch in the claw portion, in which a calibration jig is fixed in position.

2. 2. The hand according to claim 1, wherein the calibration jig has a base portion fixed to the claw portion and a pin portion extending from the base portion to a side opposite to the gripping mechanism, a protrusion protruding inward is formed on the base of the calibration jig; A hand in which the notch of the claw portion is shaped to match the convex portion of the base portion.

3. 3. The hand according to claim 1, wherein the tip of the pin of the calibration jig has a cross shape.

4. 3. The hand according to claim 1, wherein the calibration jig and the claw are provided with a jig insertion hole and a claw insertion hole, respectively, that are coaxial when the claw grips the calibration jig.

5. 3. The hand according to claim 1, further comprising an actuator with one or more degrees of freedom for changing the attitude of the gripping mechanism.

6. a part supply device that supplies the workpiece to the conveyance table; a robot that transports the workpiece from a first area where the transport table is arranged to a second area different from the first area; a hand attached to a tip of an arm of the robot, the hand picking up the workpiece on the transport table in the first area and placing the workpiece in the second area, the hand includes a gripping mechanism that moves in an opening direction to grip the workpiece and in a closing direction to release the workpiece, the gripping mechanism having a plurality of claws, and the gripping mechanism grips the workpiece with the claws by opening; The claw portion is provided with a notch in which a calibration jig is positioned and fixed, A component supply system in which the position and orientation of the calibration jig relative to the robot are fixed by opening the gripping mechanism and applying an outward force.

7. A hand attached to the tip of a robot arm to pick up a workpiece, a gripping mechanism that moves in an opening direction to grip the workpiece and in a closing direction to release the workpiece; The gripping mechanism has a plurality of claws, and when the gripping mechanism opens, the workpiece is gripped by the claws. The hand has a protrusion on the claw portion for fixing a calibration jig in position.

Images