Pad for robot hand, and robot hand

Abstract

To grip an article having a curve or a rough surface by a robot hand without complicating the structure of an articulated robot.SOLUTION: A robot hand pad disposed at fingers of a robot hand which grips an article comprises, on a surface, a plurality of columnar blocks sectioned by grooves crossing each other, and each columnar block is formed by a synthetic resin, and has an upper surface formed flat . Preferably, a through-hole is provided to penetrate from the surface to a rear surface, and fixed to the fingers of the robot hand by a fixing member inserted into the through-hole. Also preferably, the upper surface of the columnar block is rectangular, and the depth of each groove is larger than the length of each side of the upper surface of the columnar block. Further, preferably, the synthetic resin is polyurethane, nitrile rubber, hydrogenated nitrile rubber, or fluororubber.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a robot hand pad that is provided on a robot hand that grips an article of an articulated robot used for transporting, assembling, etc., of an article, and to a robot hand. [Background technology]

[0002] In recent years, automation has been progressing in the manufacturing processes of various products in the industrial world, and it has become common for industrial robots to carry out tasks such as transporting, assembling, and inspecting goods instead of workers. For example, one type of industrial robot that is widely used is the articulated robot, which is capable of movements similar to those of a human arm.

[0003] Articulated robots can move their tip along the axes of a three-dimensional Cartesian coordinate system (X-axis, Y-axis, Z-axis) and rotate their tip along the U-axis around the X-axis, the V-axis around the Y-axis, and the W-axis around the Z-axis, enabling them to perform a variety of complex movements. Therefore, articulated robots are highly versatile and are frequently used in a wide range of fields.

[0004] An articulated robot that can move an object or change its posture is equipped with a robot hand (gripper) at the tip for gripping the object. The robot hand is, for example, composed of multiple fingers, and can grip an object by arranging the fingers around the object and moving the fingers so that they approach each other (for example, see Patent Documents 1 to 4). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2011-115914 A [Patent Document 2] JP 2011-131341 A [Patent Document 3] JP 2005-153114 A [Patent Document 4] JP 2020-78857 A Summary of the Invention [Problem to be solved by the invention]

[0006] When a robot hand tries to grasp a heavy object such as a casting that has a rough curved surface with its flat fingers, the fingers and the object come into point contact. In this case, when the object is lifted, the object rotates around the contact point so that the center of gravity of the object becomes lower, and the object may lose its posture.

[0007] One possible solution is to improve the gripping mechanism of the robot hand to increase the gripping force applied to the object. However, a robot hand with high gripping force consumes a lot of power. In addition, a high-power robot hand is heavy, which increases the load on each part of the articulated robot and the movement mechanism that moves the articulated robot, and this places a greater limit on the weight of the object that can be transported.

[0008] It is also possible to increase the number of fingers on the robot hand or provide the robot hand with a mechanism that changes the orientation of the finger tips in accordance with the shape of the object, but this would complicate the configuration of the robot hand, which would directly lead to increased manufacturing costs, operating costs, and maintenance costs for the robot hand, and would increase the failure rate of the articulated robot, leading to a decrease in its operating rate.

[0009] The present invention has been made in consideration of such problems, and aims to provide a robot hand that can grasp objects with curved or rough surfaces without complicating the structure of the articulated robot, and a pad for a robot hand that enables an object to be grasped by the robot hand. [Means for solving the problem]

[0010] According to one aspect of the present invention, there is provided a pad for a robot hand that is disposed on the finger portion of a robot hand that grasps an object, the pad having a surface made of a plurality of pillar-shaped blocks that are partitioned by grooves that intersect with each other, each pillar-shaped block being made of a synthetic resin and having a flat upper surface. It has a hollow structure. The present invention provides a pad for a robot hand, comprising:

[0011] Preferably, a through hole is provided penetrating from the front surface to the back surface, and the finger portion of the robot hand is fixed by a fixing member passed through the through hole.

[0012] More preferably, the top surface of the pillar-shaped block is rectangular, and the depth of the groove is greater than the length of each side of the top surface of the pillar-shaped block.

[0013] More preferably, the synthetic resin is polyurethane, nitrile rubber, hydrogenated nitrile rubber, or fluororubber. Preferably, the filling rate of the hollow pillar block is 50% or more and 80% or less, and more preferably, the base of the pillar block is rounded.

[0014] According to another aspect of the present invention, there is provided a robot hand for grasping an object, comprising a plurality of fingers that contact the object and pinch and grasp the object, and a finger movement mechanism that can move each of the fingers in a direction to move closer to and away from each other, wherein the above-mentioned robot hand pads are arranged on the fingers. Effect of the Invention

[0015] A robot hand pad according to one aspect of the present invention has a surface including a plurality of pillar blocks partitioned by lattice-shaped grooves, each pillar block being made of synthetic resin and having a flat upper surface. Therefore, when an object is grasped by a robot hand having fingers on which the pad is arranged, each pillar block deforms to conform to the shape of the object, and the upper surface of each pillar block deforms to conform to the shape of the surface of the object. Therefore, the finger portions can contact the surface of the object over a wide area to hold the object, and the posture of the lifted object is adequately maintained.

[0016] Therefore, one aspect of the present invention provides a robot hand that can grasp objects having curved or rough surfaces without complicating the structure of the articulated robot, and a pad for a robot hand that enables the robot hand to grasp an object. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a side view showing a schematic diagram of an articulated robot. [Diagram 2] FIG. 2 is a perspective view showing a schematic diagram of a tip portion of a robot hand. [Diagram 3] FIG. 2 is a perspective view showing a schematic diagram of a pad for a robot hand. [Figure 4] Figure 4(A) is a cross-sectional view showing a schematic of how a pad for a robot hand according to an embodiment comes into contact with an object, Figure 4(B) is a cross-sectional view showing a schematic of how a pad without grooves comes into contact with an object, and Figure 4(C) is a cross-sectional view showing a schematic of how a pad with a non-flat upper end comes into contact with an object. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment according to one aspect of the present invention will be described with reference to the accompanying drawings. First, a robot hand using a robot hand pad according to this embodiment will be described. The robot hand is a part attached to the tip of a multi-joint robot used for, for example, transporting and assembling items. Fig. 1 is a side view showing a multi-joint robot (robot arm) 2.

[0019] The articulated robot 2 includes a truncated cone-shaped base 4. The base 4 may be supported by a moving mechanism, and the articulated robot 2 may be moved in the horizontal direction by moving the base 4 with the moving mechanism. A cylindrical rotating member (rotating shaft) 6 is housed in the base 4, and the upper end side of the rotating member 6 is exposed from the base 4. The base 4 also houses a rotation drive source (not shown) such as a motor connected to the lower end side of the rotating member 6. The rotating member 6 is rotated by the rotation drive source around a rotation shaft that is approximately parallel to the vertical direction (up and down direction).

[0020] A rotation mechanism (joint mechanism) 8 is connected to the upper end of the rotation member 6, and one end of a columnar arm member (lower arm portion) 10 is connected to the rotation mechanism 8. The rotation mechanism 8 is equipped with a rotation drive source such as a motor, and rotates the arm member 10 around a rotation axis that is roughly parallel to the horizontal direction. Therefore, the arm member 10 can move forward and backward with the rotation mechanism 8 as a fulcrum.

[0021] A rotation mechanism (joint mechanism) 12 is connected to the other end of the arm member 10, and one end of a columnar arm member (upper arm) 14 is connected to the rotation mechanism 12. The rotation mechanism 12 is equipped with a rotation drive source such as a motor, and rotates the arm member 14 around a rotation axis roughly parallel to the horizontal direction, and also around a rotation axis roughly parallel to the length direction of the arm member 14. The rotation mechanism 12 causes the arm member 14 to rotate around the rotation mechanism 12 and spin on its own axis.

[0022] A rotation mechanism (joint mechanism) 16 is connected to the other end of the arm member 14, and one end of a columnar arm member (wrist) 18 is connected to the rotation mechanism 16. The rotation mechanism 16 is equipped with a rotation drive source such as a motor, and rotates the arm member 18 around a rotation axis roughly parallel to the horizontal direction, and also around a rotation axis roughly parallel to the length direction of the arm member 18. The rotation mechanism 16 causes the arm member 18 to rotate around the rotation mechanism 16 and spin on its own axis.

[0023] A connection member 20 is fixed to the other end of the arm member 18. A robot hand (gripper) 22 is attached to the connection member 20. The robot hand 22 includes a plurality of fingers 28a, 28b and a finger moving mechanism 24 that moves the fingers 28a, 28b so as to approach each other.

[0024] For example, one end of rods 26a, 26b, a portion of which is housed in finger moving mechanism 24, is connected to the base end side of each of fingers 28a, 28b. An air cylinder (not shown) is incorporated inside finger moving mechanism 24, and the other end of each of rods 26a, 26b is connected to a piston (not shown) of the air cylinder. Then, by operating finger moving mechanism 24 and moving the piston inside the air cylinder to move rods 26a, 26b, each of fingers 28a, 28b can be moved toward and away from each other.

[0025] An article to be transported is placed between the tips of the fingers 28a, 28b, and the finger moving mechanism 24 is operated to move the fingers 28a, 28b closer to each other. Then, the tips of the fingers 28a, 28b come into contact with the article, and the article is held between the fingers 28a, 28b. However, the mechanism of the finger moving mechanism 24 of the robot hand 22 is not limited to this, and the fingers 28a, 28b may be moved by other methods.

[0026] The articulated robot 2 is connected wirelessly or by wire to a control unit (not shown) that controls the operation of the articulated robot 2. For example, the control unit includes a computer including a processor and a memory, and generates control signals for controlling the operation of each component of the articulated robot 2 (the rotation drive source housed in the base 4, the rotation mechanisms 8, 12, 16, the robot hand 22, etc.). This controls each component, and the articulated robot 2 grasps an article with the robot hand 22 and moves the article.

[0027] The robot hand pads 30a, 30b according to this embodiment are used by being fixed to the tips of the fingers 28a, 28b of the robot hand 22. The fingers 28a, 28b come into contact with an article via the robot hand pads 30a, 30b, and apply a gripping force to the article. Conventionally, if the robot hand pads 30a, 30b according to this embodiment are not disposed on the fingers 28a, 28b, the robot hand 22 may not be able to hold the article appropriately depending on the shape, surface irregularity, and hardness of the article to be transported.

[0028] For example, when an object such as a casting that has many curved surfaces, is hard, and has a rough surface is pinched and grasped between the flat finger portions 28a, 28b, the contact area between the finger portions 28a, 28b and the object may become extremely small. When the object is lifted in this state, the object rotates around the contact point so that the center of gravity of the object becomes lower, and the object's posture changes. In particular, the heavier the object is, the greater the force that rotates the object becomes, so it is not easy to continue to grasp a heavy object with the robot hand 22 while maintaining the posture.

[0029] Therefore, in order to increase the contact area between the fingers 28a, 28b and the article, it is conceivable to change the material of the fingers 28a, 28b themselves to a soft and easily deformed material. In this case, when the fingers 28a, 28b grip an article, the contact surface of the fingers 28a, 28b is deformed to follow the shape and rough surface of the article, and the contact area increases. However, if the fingers 28a, 28b themselves are soft, the fingers 28a, 28b will be deformed by the reaction force from the article. Therefore, since a large gripping force cannot be applied to the article, the article will easily slip off and fall.

[0030] Therefore, it is preferable that the pads 30a, 30b for a robot hand according to this embodiment are attached to the tips of the finger parts 28a, 28b. Fig. 2 is a perspective view showing the tips of the finger parts 28a, 28b to which the pads 30a, 30b for a robot hand according to this embodiment are attached. Fig. 3 is a perspective view showing the pads 30, 30a, 30b for a robot hand according to this embodiment. The pads 30, 30a, 30b for a robot hand according to this embodiment will be described below.

[0031] The robot hand pad 30 according to this embodiment has a surface 32a with a plurality of pillar blocks 34 partitioned by lattice-like grooves 38. Each pillar block 34 is made of synthetic resin and has a flat upper surface 36. The robot hand pad 30 may have a flat base (not shown) that supports each pillar block 34. Alternatively, the entire pad may be made of the synthetic resin.

[0032] The robot hand pad 30 may be provided with a through hole 40 that penetrates from the front surface 32a to the back surface 32b. In this case, the pad 30 is fixed to the fingers 28a, 28b of the robot hand 22 by a fixing member 42 such as a bolt or screw that is passed through the through hole 40.

[0033] The pad 30 for a robot hand can be manufactured, for example, by a 3D printer using a synthetic resin material as ink. When forming the pad 30 for a robot hand with a 3D printer, it is not necessary to use an ink material so as to fill the entire area of ​​the pillar-shaped block 34, and the pillar-shaped block 34 may have a hollow structure. As will be described in detail later, if the pillar-shaped block 34 has a hollow structure, the pillar-shaped block 34 becomes easily deformed, and this may increase the gripping force of the robot hand 22 on an object.

[0034] The resin material may be provided so as to configure the outer surface of the pillar-shaped block 34, and for example, the ratio (filling rate) of the area occupied by the resin material to the area occupied by the pillar-shaped block 34 is preferably about 50%. If the filling rate of the pillar-shaped block 34 is significantly lower than 50%, the shape of the pillar-shaped block 34 is not sufficiently maintained, and the robot hand 22 cannot apply a sufficient gripping force to the article. On the other hand, if the filling rate is too high, the rigidity of the pillar-shaped block 34 increases, making it difficult for the pillar-shaped block 34 to deform to follow the shape of the article. For example, the filling rate of the pillar-shaped block 34 is preferably 50% or more and 80% or less.

[0035] However, the method for manufacturing the pads 30a and 30b for the robot hand is not limited to this. For example, the pads 30 for the robot hand may be manufactured by preparing a plate made of a synthetic resin material and forming a lattice-like groove 38 on the surface of the plate using a tool having a saw blade.

[0036] Here, the functions of the pillar block 34 and the groove 38 when the fingers 28a, 28b of the robot hand 22 grip an article via the robot hand pad 30 will be described. Fig. 4(A) is a schematic enlarged cross-sectional view showing the surfaces of the robot hand pads 30, 30a, 30b that come into contact with the article 1 to be transported by the articulated robot 2. However, for ease of explanation, Fig. 4(A) emphasizes the shape and deformation of the pillar block 34.

[0037] 4(A), when the columnar blocks 34 come into contact with the article 1, they deform to follow the shape of the article 1. More specifically, the columnar blocks 34 bend as a result of the article 1 being held between the fingers 28a and 28b exerting a repulsive force on the columnar blocks 34 that come into contact with the article 1. As a result, a wide area of ​​the upper surface 36 of the columnar blocks 34 comes into contact with the article 1, even at the outer periphery of the contact region of the surface 1a of the article 1.

[0038] The deformation of the pillar-shaped blocks 34 is achieved by providing lattice-shaped grooves 38 on the surface 32a of the pad 30 for the robot hand. That is, when the grooves 38 are formed between the pillar-shaped blocks 34, the spaces of the grooves 38 provide room for deformation and displacement of the pillar-shaped blocks 34. Therefore, the surface 32a of the pad 30 for the robot hand is more likely to deform to follow the surface 1a of the article 1 compared to a case in which the grooves 38 are not formed.

[0039] Fig. 4(B) is a cross-sectional view showing a state where a pad 44 without grooves 38 is brought into contact with a surface 1a of an article 1. As shown in Fig. 4(B), a surface 44a of the pad 44 without grooves 38 is continuous over a wide area without being divided. Therefore, when the pad 44 receives a repulsive force from the article 1 at the contact point with the article 1, the surface 44a is deformed not only at the contact point but also on the outside thereof, and the surface 1a of the article 1 and the surface 44a of the pad 44 are separated from each other on the outside. In other words, the contact area between the two is unlikely to increase.

[0040] 4(C), it is also possible to grasp the article 1 via a pad 46 having a plurality of pyramidal blocks 48 arranged on its surface, each of which has an uneven upper surface. In this case, groove-like spaces 50 are provided between the blocks 48, but when the article 1 is grasped via the pad 46, the contact area between the pad 46 and the article 1 does not increase significantly even if the blocks 48 are deformed.

[0041] Unlike the pad 44 shown in Fig. 4(B) and the pad 46 shown in Fig. 4(C), the pad 30 for a robot hand according to this embodiment shown in Fig. 3(A) is provided with a plurality of pillar-shaped blocks 34 and lattice-shaped grooves 38, and the top surface 36 of the pillar-shaped blocks 34 is flat. Therefore, when an article 1 is grasped via the pad 30 for a robot hand, the pillar-shaped blocks 34 are deformed, and the top surface 36 of the pillar-shaped blocks 34 comes into contact with the article 1 over a wide area.

[0042] The pad 30 for a robot hand is also suitable for use when the robot hand 22 grasps an article 1 that is wet and has water adhering to its surface 1a. The grooves 38 provided on the surface 32a of the pad 30 for a robot hand provide an escape route for the water adhering to the surface 1a of the article 1. Therefore, when the article 1 is grasped via the pad 30 for a robot hand, no layer of water is formed between them, making it difficult for the article 1 to slip relative to the pad 30 for a robot hand.

[0043] Therefore, when the robot hand pad 30 according to this embodiment is provided on the fingers 28a, 28b, any object 1 can be easily grasped by the robot hand 22. In addition, the posture of the grasped object 1 is less likely to change.

[0044] In particular, as shown in Fig. 3 etc., when the top surface 36 of the pillar-shaped block 34 is rectangular or square and the depth of the groove 38 is greater than the length of each side of the top surface 36 of the pillar-shaped block 34, the pillar-shaped block 34 becomes more easily deformed. Therefore, the posture of the article 1 being grasped is hardly changed.

[0045] For example, the depth of the lattice-shaped grooves 38 is preferably greater than 1 time and less than 3 times the length of one side of the top surface 36 of one pillar-shaped block 34. Furthermore, it is more preferable that the depth be 1.5 times or more and less than 2 times the length of one side of the top surface 36. For example, if the top surface 36 of one pillar-shaped block 34 is a square with sides of 4 mm, it is preferable that the depth of the grooves 38 is about 7 mm and the width is about 1 mm. When the depth and width of the grooves 38 are determined in this manner, the pillar-shaped block 34 has sufficient flexibility and can apply a sufficient gripping force to the article 1.

[0046] It is preferable that the base of the pillar-shaped block 34 be rounded as shown in Fig. 3 rather than square, which is prone to stress concentration. In the pad 30 for a robot hand according to this embodiment, it is assumed that the pillar-shaped block 34 will be deformed on a daily basis. Therefore, in order to increase the durability of the pillar-shaped block 34, it is preferable that the base of the pillar-shaped block 34 be rounded and that the pillar-shaped block 34 become thicker toward the base. In this case, the bottom of the groove 38 is rounded.

[0047] Moreover, the synthetic resin used in the robot hand pad 30 according to this embodiment is preferably a material such as polyurethane, nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), fluororubber, etc. When the synthetic resin used in the robot hand pad 30 is of these materials, the columnar block 34 is easily elastically deformed and a sufficient gripping force can be applied to the article 1.

[0048] As described above, when the robot hand pad 30 according to this embodiment is disposed on the fingers 28a, 28b of the robot hand 22 of the articulated robot 2, even an object 1 having a rough, curved surface and heavy weight can be adequately grasped by the robot hand 22. Furthermore, while being transported by the articulated robot 2, the object 1 is less likely to rotate and its posture is more easily maintained.

[0049] In the above embodiment, the robot hand pad 30 is used with the robot hand 22 having two fingers 28a, 28b, but the present invention is not limited to this. For example, the robot hand 22 may have three or more fingers, and the robot hand pad 30 may be provided on each of the fingers.

[0050] In the above embodiment, the robot hand pads 30 are provided on all the fingers 28a, 28b of the robot hand 22 of the articulated robot 2, but the present invention is not limited to this. The robot hand pads 30 may be provided on only some of the fingers 28a, 28b of the robot hand 22.

[0051] Furthermore, in the above embodiment, the case where the robot hand pad 30 is used in the robot hand 22 of the industrial articulated robot 2 has been described, but one aspect of the present invention is not limited to this. That is, the robot hand pad 30 according to one aspect of the present invention may be used in other robot hands, or may be disposed and used in tools other than robot hands.

[0052] In the above embodiment, the robot hand pad 30 is partitioned by the lattice-shaped grooves 38, and the upper surfaces 36 of the plurality of pillar-shaped blocks 34 are rectangular or square. That is, the pillar-shaped blocks 34 are rectangular parallelepiped-shaped, but one aspect of the present invention is not limited to this.

[0053] For example, the shape of the top surface 36 of the pillar-shaped block 34 may be a rectangle such as a rhombus, a trapezoid, or a parallelogram, and the pillar-shaped block 34 may be a quadrangular prism other than a rectangular parallelepiped. In addition, the top surface 36 of the pillar-shaped block 34 may be a polygonal shape such as a hexagon or an octagon, and the pillar-shaped block 34 may be a polygonal prism such as a hexagonal prism or an octagonal prism.

[0054] Furthermore, the multiple pillar blocks 34 included in the pad 30 for a robot hand do not all need to be the same size and shape. The pad 30 for a robot hand may include multiple types of pillar blocks 34 having different sizes and shapes of the upper surfaces 36. In addition, the groove 38 does not need to be continuous from one end of the pad 30 for a robot hand to the other end.

[0055] The structures, methods, and the like according to the above-described embodiments can be modified as appropriate without departing from the scope of the object of the present invention. [Explanation of symbols]

[0056] 1 article 1a surface 2 Articulated robots (robot arms) 4 Foundation 6 Rotating parts (rotating shafts) 8 Rotation mechanism (joint mechanism) 10 Arm member (lower arm) 12 Rotation mechanism (joint mechanism) 14 Arm member (upper arm) 16 Rotation mechanism (joint mechanism) 18 Arm member (wrist) 20 Connection member 22 Robot Hand 24 Finger movement mechanism 26a, 26b Rod 28a,28b Finger part 30, 30a, 30b Pad for robot hand 32a surface 32b back side 34 Pillar Block 36 Top 38 Groove 40 Through hole 42 Fixing member 44 Pad 44a surface 46 Pad 48 blocks 50 space

Claims

1. A pad for a robot hand that is provided on a finger portion of a robot hand that grasps an object, The plate has a surface having a plurality of pillar-shaped blocks partitioned by grooves intersecting each other, A pad for a robot hand, characterized in that each columnar block is made of synthetic resin, has a flat upper surface, and is hollow.

2. A through hole is provided penetrating from the front surface to the back surface, 2. The pad for a robot hand according to claim 1, wherein the pad is fixed to the finger portion of the robot hand by a fixing member passed through the through hole.

3. The top surface of the pillar block is rectangular, 3. The pad for a robot hand according to claim 1, wherein the depth of the groove is greater than the length of each side of the upper surface of the pillar-shaped block.

4. 4. The pad for a robot hand according to claim 1, wherein the synthetic resin is polyurethane, nitrile rubber, hydrogenated nitrile rubber, or fluororubber.

5. A pad for a robot hand as described in any one of claims 1 to 4, characterized in that the filling rate of the columnar block having a hollow structure is 50% or more and 80% or less.

6. A pad for a robot hand as described in any one of claims 1 to 5, characterized in that the base of the cylindrical block is rounded in shape.

7. A robot hand that grasps an object, a plurality of finger portions that come into contact with the article to pinch and grip the article; and a finger portion moving mechanism that can move each of the finger portions in a direction to move closer to and away from each other, A robot hand, comprising a pad for a robot hand according to any one of claims 1 to 6 disposed on the finger portion.

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