Robot

Abstract

This robot comprises: a base part; a first motor having a first drive axis in a specific direction and attached to the base part; a second motor having a second drive axis coaxial with the first drive axis, and attached to the base part; a first link rotated by the first motor around the first drive axis; a second link rotated by the second motor around the second drive axis; a first joint provided on the first link and having a first rotation axis; a second joint provided on the second link and having a second rotation axis; a third link connected to the first joint and rotatable around the first rotation axis; a fourth link connected to the second joint and rotatable around the second rotation axis; a third joint provided on the third link, having a third rotation axis, and having the fourth link rotatably connected thereto; and an end effector attachment part provided on the third link.

Description

robot

[0001] The present disclosure relates to robots.

[0002] Japanese Patent Application Laid-Open Publication No. 2000-300823 describes an air hockey game device equipped with a manipulator. The manipulator is composed of a stick, a robot arm with the stick attached to the tip, and a drive means for causing the stick to hit the ball.

[0003] In the air hockey game device disclosed in Japanese Patent Laid-Open Publication No. 2000-300823, a manipulator extends from a monitor board. The manipulator is a so-called serial link mechanism in which a plurality of links are connected in series by joints.

[0004] In a serial link structure, the drive source for driving the distal link is provided at the joint. In this case, since the joint is separated from the proximal end (the monitor panel in the example of JP 2000-300823 A), the gravitational moment of the drive source acts on the serial link mechanism. If the links and joints are reinforced to suppress deformation and displacement of the serial link mechanism due to this moment, this will result in an increase in the weight of the moving parts of the serial link mechanism.

[0005] Furthermore, in a robot having a serial link mechanism, when controlling the position of the tip side (the stick in the example of JP-A-2000-300823), it is desirable to control it more simply.

[0006] The present disclosure aims to reduce the weight of moving parts and simplify position control on the tip side of a robot having a serial link mechanism.

[0007] One aspect of the present disclosure includes a base, a first motor having a first drive shaft oriented in a specific direction and attached to the base, a second motor having a second drive shaft coaxial with the first drive shaft and attached to the base, a first link rotated by the first motor around the first drive shaft within a plane of rotation normal to the specific direction, a second link rotated by the second motor around the second drive shaft within a plane of rotation normal to the specific direction, a first joint provided on the first link and having a first rotation shaft, a second joint provided on the second link and having a second rotation shaft, a third link connected to the first joint and rotatable about the first rotation shaft, a fourth link connected to the second joint and rotatable about the second rotation shaft, a third joint provided on the third link and having a third rotation shaft, and to which the fourth link is rotatably connected, and an end effector attachment portion provided on the third link.

[0008] According to the present disclosure, in a robot having a serial link mechanism, the moving part can be made lighter and position control on the tip side can be simplified.

[0009] Fig. 1 is a bottom view showing a robot of a first embodiment. Fig. 2 is a front view showing a robot of the first embodiment. Fig. 3 is a side view showing a robot of the first embodiment. Fig. 4 is an explanatory diagram showing the rotation state of links of the robot of the first embodiment. Fig. 5 is a bottom view showing a robot of a second embodiment. Fig. 6 is a bottom view showing a robot of a third embodiment.

[0010] A robot 12, which is an example of an embodiment of the present disclosure, will be described below with reference to the drawings. Note that the same or substantially equivalent elements, members, and parts in each drawing are given the same reference numerals. Also, the dimensions and proportions in the drawings have been exaggerated for the sake of explanation and may differ from the actual proportions.

[0011] The robot 12 can be used, for example, in a game in which players hit a puck on a board (a so-called air hockey game), by moving a mallet (described later) on the board to hit the puck used in the game.

[0012] As shown in FIGS. 1 to 3 , the robot 12 of the first embodiment has a base 14, a first motor 16, a second motor 18, and an arm 20. The base 14 is installed on, for example, an installation surface SF. With the robot 12 installed on the installation surface SF, an X-axis, a Y-axis, and a Z-axis are set as a coordinate system. The X-axis direction is the front-to-rear direction of the robot 12, the Y-axis is the left-to-right direction of the robot 12, and the Z-axis is the height direction of the robot 12. In the illustrated example, the plane (XY plane) on which the arm 20 operates is a horizontal plane, but the plane on which the arm 20 operates may also be, for example, a vertical plane (vertical plane) or an inclined plane that is inclined at any angle relative to the horizontal plane.

[0013] The base 14 includes a base 22 and a support column 24. In the illustrated example, the base 22 has two support beams arranged at right angles to each other. The support column 24 extends upward from one of the support beams.

[0014] The first motor 16 and the second motor 18 have housings 16H and 18H. The housings 16H and 18H are attached to the support 24 by brackets 30. In the illustrated example, the first motor 16 is disposed above the second motor 18.

[0015] The first motor 16 has a first drive shaft 26. The first drive shaft 26 extends downward from the housing 16H along the Z-axis direction. That is, the Z-axis direction is the specific direction of the first drive shaft 26.

[0016] The second motor 18 has a second drive shaft 28. The second drive shaft 28 extends upward from the housing 16H along the Z-axis direction. The second drive shaft 28 is coaxial with the first drive shaft 26. In other words, the housings 16H, 18H of the first motor 16 and the second motor 18, respectively, are attached to the support 24 so that the first drive shaft 26 and the second drive shaft 28 are coaxial.

[0017] The arm unit 20 has a first link 32, a second link 34, a third link 36, and a fourth link 38. In the first embodiment, the first link 32, the second link 34, the third link 36, and the fourth link 38 are linear. The arm unit 20 is an example of a movable unit according to the disclosed technology.

[0018] One end of the first link 32 is attached to the first drive shaft 26. When driven by the first motor 16, the first link 32 is rotated within a rotation plane RP1 having the Z-axis direction as its normal line. In this case, the Z-axis direction is the "specific direction" in the disclosed technology.

[0019] One end of the second link 34 is attached to the second drive shaft 28. Driven by the second motor 18, the second link 34 rotates within a plane of rotation RP2, the normal of which is the Z-axis direction. In the illustrated example, the second link 34 is disposed below the first link 32, and therefore the plane of rotation RP2 is also below the plane of rotation RP1. Because the plane of rotation RP1 of the first link 32 and the plane of rotation RP2 of the second link 34 are offset in this specific direction, the first link 32 and the second link 34 do not interfere with each other when they rotate.

[0020] A first joint 42 is provided at the other end of the first link 32. The first joint 42 has a first rotation shaft 52. The first rotation shaft 52 is parallel to the first drive shaft 26. Note that the first rotation shaft 52 itself may be formed on the first link 32, for example, and the first rotation shaft 52 may be inserted into the first joint 42, so that the first joint 42 essentially has the first rotation shaft 52. The same relationship applies to the following joints and corresponding rotation shafts.

[0021] A second joint 44 is provided at the other end of the second link 34. The second joint 44 has a second rotation shaft 54. The second rotation shaft 54 ​​is parallel to the second drive shaft 28. Therefore, the second rotation shaft 54 ​​is also parallel to the first rotation shaft 52.

[0022] One end of the third link 36 is connected to the first joint 42. The third link 36 is rotatable around a first rotation shaft 52 located at one end of the third link 36.

[0023] One end of the fourth link 38 is connected to the second joint 44. The fourth link 38 is rotatable around a second rotation shaft 54 ​​located at one end thereof.

[0024] A third joint 46 is provided at the other end of the third link 36. The third joint 46 has a third rotation shaft 56. The third rotation shaft 56 is parallel to the first rotation shaft 52 and the second rotation shaft 54. This results in a structure in which the first drive shaft, the second drive shaft 28, the first rotation shaft 52, the second rotation shaft 54, and the third rotation shaft 56 are parallel to one another.

[0025] The other end of the fourth link 38 is connected to the third joint 46. The fourth link 38 is rotatable relative to the third link 36 around a third rotation shaft 56 located at the other end.

[0026] In this embodiment, as shown in FIG. 4 , when viewed in the Z-axis direction, a line segment LS1 connecting the first drive shaft 26 and the first rotation shaft 52 is parallel to a line segment LS4 connecting the second rotation shaft 54 ​​and the third rotation shaft 56, and they are the same length. As a result, a line segment LS2 connecting the second drive shaft 28 and the second rotation shaft 54 ​​and a line segment LS3 connecting the first rotation shaft 52 and the third rotation shaft 56 are also parallel to each other and have the same length. In other words, a parallelogram is formed with the first link 32, the second link 34, the third link 36, and the fourth link 38 as its four sides. In the illustrated example, the line segments LS2 and LS3 are shorter than the line segments LS1 and LS4. Furthermore, each of the line segments LS1, LS2, LS3, and LS4 is perpendicular to the drive shaft or rotation shaft at each end.

[0027] The third link 36 is provided with a mallet attachment piece 40. In the bottom view shown in Fig. 1, the mallet attachment piece 40 has a shape that extends linearly from one end (first joint 42) of the third link 36 to the other end (third joint 46). In the front view shown in Fig. 2 and the side view shown in Fig. 3, the mallet attachment piece 40 is formed in a linear shape that slopes obliquely downward from the position of the third joint 46 toward the tip.

[0028] The tip of the mallet attachment piece 40 is a mallet attachment portion 50. A mallet 48 is attached to the mallet attachment portion 50. In the illustrated example, the mallet 48 is formed in a flat cylindrical shape. The mallet 48 is an example of an end effector, and the mallet attachment portion 50 is an example of an end effector attachment portion. In this example, the mallet attachment portion 50 is indirectly attached to the third link 36 via the mallet attachment piece 40, but the mallet attachment portion 50 is not limited to being attached to the tip of the mallet attachment piece 40. For example, the mallet attachment piece 40 may be omitted, and the mallet attachment portion 50 may be directly attached to the other end of the third link 36, i.e., at the position of the third joint 46. In either configuration, the mallet attachment portion 50 is located at the tip of the arm unit 20 and the robot 12, and the mallet 48 is located at this tip side.

[0029] In this embodiment, the first link 32, the third link 36, and the mallet attachment piece 40 are substantially connected in series, and each link from the first drive shaft 26 to the mallet attachment portion 50 forms a serial link mechanism. The serial link mechanism includes the second link 34 and the fourth link 38, making it possible to adjust the position of the mallet attachment portion 50.

[0030] Next, the operation of this embodiment will be described.

[0031] As shown in FIG. 4 , in the robot 12, the first link 32 rotates about the first drive shaft 26 when driven by the first motor 16 (see FIGS. 1 to 3 ). For example, as shown by the dashed-dotted line in FIG. 4 , the rotation angle θ1 of the first link 32 can be adjusted to a predetermined angle with respect to a predetermined reference line BL. Furthermore, the second link 34 rotates about the second drive shaft 28 when driven by the second motor 18. For example, the rotation angle θ2 of the second link 34 can be adjusted to a predetermined angle with respect to the reference line BL. Then, by appropriately adjusting the rotation angle θ1 of the first link 32 and the rotation angle θ2 of the second link 34, the mallet 48 can be moved to a desired position.

[0032] 1 to 3, the first motor 16 and the second motor 18 are provided on the support 24, i.e., the base 14. It is also possible to provide a motor for moving the mallet 48 to a desired position on the first link 32, the second link 34, or the like, but in this case the weight of the arm portion 20 would increase.

[0033] In contrast, in the robot 12 of this embodiment, the first motor 16 and the second motor 18 are provided on the base 14, so the arm 20 can be made lighter.

[0034] Furthermore, since the first link 32 and the second link 34 rotate around one end of each (the support 24 side) as a fulcrum, if the motor is installed at a position away from the support 24, the moment of inertia of the arm portion 20 centered on the support 24 becomes larger compared to a configuration in which the motor is installed on the support 24.

[0035] In contrast, in the robot 12 of this embodiment, the first motor 16 and the second motor 18 are provided on the base 14, so the moment of inertia of the arm 20 around the base 14 is also reduced.

[0036] Furthermore, in the robot 12 of this embodiment, the first drive shaft 26 of the first motor 16 and the second drive shaft 28 of the second motor 18 are coaxial. Even if the first drive shaft 26 of the first motor 16 and the second drive shaft 28 of the second motor 18 are not coaxial, it is possible to rotate the first link 32 and the second link 34, respectively. However, if the first drive shaft 26 and the second drive shaft 28 are not coaxial, adjusting the rotation angle θ1 of the first link 32 and the rotation angle θ2 of the second link 34 to control the position of the mallet 48 may become complicated. In contrast, in the robot 12 of this embodiment, the first drive shaft 26 and the second drive shaft 28 are coaxial, so adjusting the rotation angle θ1 of the first link 32 and the rotation angle θ2 of the second link 34 to control the position of the mallet 48 can be simplified. In other words, simplifying the adjustment of the rotation angle θ1 of the first link 32 and the rotation angle θ2 of the second link 34 also simplifies control of the position of the mallet 48.

[0037] In particular, in the robot 12 of this embodiment, the line segment LS1 and the line segment LS4 are parallel and of the same length, forming a parallelogram with the first link 32, the second link 34, the third link 36, and the fourth link 38 as its four sides. Therefore, as can be seen from FIG. 4 , the rotation angle θ3 of the third link 36 relative to the line segment LS1 is the difference between the rotation angle θ2 of the second link 34 and the rotation angle θ1 of the first link 32, and is calculated as θ3 = θ2 - θ1. In other words, the angle of the third link 36 relative to the reference line BL is equal to the rotation angle θ2 of the second link 34. This makes it easier to control the position of the mallet 48 compared to a configuration in which the line segment LS1 and the line segment LS2 are parallel and of unequal lengths.

[0038] In the robot 12 of the first embodiment, the first link 32, the second link 34, the third link 36, and the fourth link 38 are all straight, which allows for a simpler structure compared to a configuration in which these links are bent.

[0039] Next, a second embodiment will be described. In the following embodiments, the same elements, members, etc. as those in the first embodiment will be denoted by the same reference numerals as those in the first embodiment, and detailed description thereof will be omitted.

[0040] 5, in the robot 62 of the second embodiment, the fourth link 68 is curved in a shape that deviates from the line segment LS4 in plan view. In the example shown in the figure, the entire fourth link 68 is curved, and the curvature in plan view gradually increases from the other end (the third rotation shaft 56 side) to one end (the second rotation shaft 54 ​​side).

[0041] Furthermore, a part or all of the fourth link 68 is provided at a height position that overlaps with the housing 16H of the second motor 18 in the Z-axis direction. In other words, the fourth link 68 is curved so as not to interfere with the housing 16H even when the fourth link 68, which overlaps with the housing 16H in the height direction, rotates.

[0042] In the robot 62 of the second embodiment, the fourth link 68 can be disposed at a height position that overlaps with the housing 16H of the second motor 18 in the Z-axis direction. Compared to the robot 12 of the first embodiment, the fourth link 68 can be disposed at a lower position, which allows the overall height of the robot 62 to be reduced. In particular, if the second link 34 is formed short, for example, to reduce the moment of inertia, the third link 36 is likely to interfere with the housing 16H. However, in the robot 62 of the second embodiment, the second link 34 is shortened to reduce the moment of inertia, and a structure can be realized in which the fourth link 68 does not interfere with the housing 16H.

[0043] The member with which the fourth link 68 must avoid interference is not limited to the housing 18H of the second motor 18. For example, the fourth link 68 may be bent in an appropriate shape to avoid interference with various members that are preferably disposed within the rotation trajectory of the fourth link 68.

[0044] The shape of the bent fourth link 68 may have a constant curvature in a plan view, or the curvature may gradually decrease from the other end to the one end. Furthermore, the bent portion of the fourth link 68 may be a part of the fourth link 68 rather than the entire fourth link 68. Furthermore, the fourth link 68 may be bent into a shape that deviates from the line segment LS2 by bending rather than curving, or by a combination of bending and curving.

[0045] Next, a third embodiment will be described.

[0046] 6, in a robot 72 of the third embodiment, the second link 74 is curved in a shape that deviates from the line segment LS2 in a plan view. In the example shown, the entire second link 74 is curved, and the curvature in a plan view gradually increases from the other end (the second rotation shaft 54 ​​side) to one end (the second drive shaft 28 side). The second link 74 is curved so as not to interfere with the components around the second link 74 even when the second link 74 rotates.

[0047] Therefore, the robot 72 of the third embodiment is configured so that the second link 74 does not interfere with other members when it rotates. As in the second embodiment, the members that the second link 74 must avoid interfering with when it rotates are not particularly limited. For example, the second link 74 may have a shape that avoids interference with the housing 18H of the second motor 18, or may have a shape that avoids interference with members other than the housing 18H.

[0048] Furthermore, the curvature of the bent second link 74 may be constant in a plan view, or may gradually decrease from the other end to the one end. The portion of the second link 74 that is bent may be only a part of the second link 74, rather than the entire second link 74. The second link 74 may be bent into a shape that deviates from the line segment LS2 by bending instead of curving, or by combining bending and curving.

[0049] In the disclosed technology, the end effector is not limited to the mallet 48, and may be any of various effectors that perform a predetermined process on a processing target. For example, it may be a hand that grips the processing target, a suction pad, or the like.

[0050] Furthermore, the disclosed technology is not particularly limited to the use of the robot, and may be applied as a robot used for, for example, sorting or picking luggage, or transporting experimental equipment such as test tubes in a laboratory.

[0051] The following are supplementary notes related to the present disclosure: (Supplementary Note 1) A robot comprising: a base, a first motor having a first drive shaft oriented in a specific direction and attached to the base, a second motor having a second drive shaft coaxial with the first drive shaft and attached to the base, a first link rotated by the first motor about the first drive shaft within a plane of rotation normal to the specific direction, a second link rotated by the second motor about the second drive shaft within a plane of rotation normal to the specific direction, a first joint provided on the first link and having a first rotation shaft, a second joint provided on the second link and having a second rotation shaft, a third link connected to the first joint and rotatable about the first rotation shaft, a fourth link connected to the second joint and rotatable about the second rotation shaft, a third joint provided on the third link and having a third rotation shaft to which the fourth link is rotatably connected, and an end effector attachment portion provided on the third link. (Supplementary Note 2) The robot according to Supplementary Note 1, wherein a line segment connecting the second rotation axis and the third rotation axis is parallel to and has the same length as a line segment connecting the first drive axis and the first rotation axis. (Supplementary Note 3) The robot according to Supplementary Note 1 or Supplementary Note 2, wherein the second link and the fourth link are straight. (Supplementary Note 4) The robot according to Supplementary Note 1 or Supplementary Note 2, wherein at least a portion of the second link is bent in a shape that deviates from a line segment connecting the second drive axis and the second rotation axis when viewed in the specific direction. (Supplementary Note 5) The robot according to Supplementary Note 1, Supplementary Note 2, or Supplementary Note 4, wherein at least a portion of the fourth link is bent in a shape that deviates from a line segment connecting the second rotation axis and the third rotation axis when viewed in the specific direction. (Supplementary Note 6) The robot according to any one of Supplementary Notes 1 to 5, including an end effector attached to the end effector attachment portion.

[0052] The disclosure of Japanese Patent Application No. 2023-200022, filed on November 27, 2023, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards mentioned herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

Claims

a first motor having a first drive shaft oriented in a specific direction and attached to the base; a second motor having a second drive shaft coaxial with the first drive shaft and attached to the base; a first link rotated by the first motor about the first drive shaft within a plane of rotation having the specific direction as its normal; a second link rotated by the second motor about the second drive shaft within a plane of rotation having the specific direction as its normal; a first joint provided on the first link and having a first rotation shaft; a second joint provided on the second link and having a second rotation shaft; a third link connected to the first joint and rotatable about the first rotation shaft; a fourth link connected to the second joint and rotatable about the second rotation shaft; a third joint provided on the third link and having a third rotation shaft to which the fourth link is rotatably connected; and an end effector attachment portion provided on the third link.

2. The robot according to claim 1, wherein a line segment connecting the second rotation axis and the third rotation axis is parallel to and has the same length as a line segment connecting the first drive axis and the first rotation axis.

3. The robot according to claim 1, wherein the second link and the fourth link are linear.

4. The robot according to claim 1, wherein at least a portion of the second link is bent in a shape that deviates from a line segment connecting the second drive shaft and the second rotation shaft when viewed in the specific direction.

5. The robot according to claim 1, wherein at least a portion of the fourth link is bent in a shape that deviates from a line segment connecting the second rotation axis and the third rotation axis when viewed in the specific direction.

6. The robot according to claim 1, further comprising an end effector attached to said end effector attachment portion.

Images