Robot joint structure and robot

Abstract

A robot joint structure (100a) according to the present invention is provided with a driving force transmission unit (30) including a rotating shaft member (31) that is rotated by rotational driving of a first motor (40) and a second motor (50). The driving force transmission unit (30) rotates the first link member (11) and the second link member (12) relative to each other by the rotation of the rotating shaft member (31). Furthermore, the robot joint structure (100a) is provided with: a first belt (60) that transmits the rotational drive of the first motor (40) to the rotating shaft member (31); and a second belt (70) that transmits the rotational drive of the second motor (50) to the rotating shaft member (31).

Description

Technical Field

[0001] The present disclosure relates to a robot joint structure and a robot, and particularly to a robot joint structure and a robot using a plurality of motors as drive sources. Background Art

[0002] Conventionally, a robot joint structure using a plurality of motors as drive sources has been known. For example, in Japanese Unexamined Patent Application Publication No. 2019-076992, a hip joint structure in a bipedal walking robot that drives a link by a first motor and a second motor is disclosed. In this hip joint structure, the first motor and the second motor are used as drive sources, and an opening / closing link as a leg-side member rotates relative to a rotating link as a waist-side member in the bipedal walking robot. Specifically, the hip joint structure of Japanese Unexamined Patent Application Publication No. 2019-076992 includes a first drive wheel, a second drive wheel, a rolling wheel, and a driven wheel. The first drive wheel and the second drive wheel are respectively connected to the output shafts of the first motor and the second motor. An endless belt is hung on the first drive wheel, the second drive wheel, the rolling wheel, and the driven wheel. By rotating the second motor following the first motor, the driving forces of the first motor and the second motor are transmitted to the driven wheel via the endless belt. With the driving force transmitted to the driven wheel, the leg-side opening / closing link rotates relative to the waist-side rotating link. In addition, the first drive wheel, the rolling wheel, and the driven wheel are arranged inside the endless belt, and the second drive wheel is arranged outside the endless belt. That is, both the inner side and the outer side of the endless belt are used to transmit the driving force.

[0003] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2019-076992

[0004] However, in the case of using both the inner side and the outer side of an endless belt to transmit the driving forces of a plurality of motors as in the joint structure of the robot described in Japanese Unexamined Patent Application Publication No. 2019-076992, a belt having tooth portions or contact surfaces for transmitting the driving force on both sides is required. Such a belt having tooth portions or contact surfaces on both sides is not common, and thus it is desired to use a plurality of motors as drive sources without using both sides of the belt for transmitting the driving force. Summary of the Invention

[0005] The present disclosure has been made to solve the above-described problems, and an object of the present disclosure is to provide a robot joint structure and a robot capable of using a plurality of motors as drive sources without using both sides of a belt for transmitting the driving force.

[0006] The robot joint structure according to the first aspect of the present disclosure includes: a first link member and a second link member, which are connected to each other via a joint portion; a first motor and a second motor, which serve as drive sources for relatively rotating the first link member and the second link member; a driving force transmission portion, which includes a rotating shaft member that rotates by the rotational drive of the first motor and the second motor, and relatively rotates the first link member and the second link member by the rotation of the rotating shaft member; a first belt that transmits the rotational drive of the first motor to the rotating shaft member; and a second belt that transmits the rotational drive of the second motor to the rotating shaft member.

[0007] As described above, the robot joint structure according to the first aspect of the present disclosure includes: a first belt that transmits the rotational drive of the first motor to the rotating shaft member; and a second belt that transmits the rotational drive of the second motor to the rotating shaft member. Thus, even when a plurality of motors such as the first motor and the second motor are used as drive sources, the driving force can be transmitted by using only one side of each of the first belt and the second belt. As a result, a plurality of motors can be used as drive sources without using both sides of the belt for transmitting the driving force.

[0008] The robot according to the second aspect of the present disclosure includes: a first link member and a second link member, which are connected to each other via a joint portion; a first motor and a second motor, which serve as drive sources for relatively rotating the first link member and the second link member; a driving force transmission portion, which includes a rotating shaft member that rotates by the rotational drive of the first motor and the second motor, and relatively rotates the first link member and the second link member by the rotation of the rotating shaft member; a first belt that transmits the rotational drive of the first motor to the rotating shaft member; and a second belt that transmits the rotational drive of the second motor to the rotating shaft member.

[0009] As described above, the robot according to the second aspect of the present disclosure includes: a first belt that transmits the rotational drive of the first motor to the rotating shaft member; and a second belt that transmits the rotational drive of the second motor to the rotating shaft member. Thus, even when a plurality of motors such as the first motor and the second motor are used as drive sources, the driving force can be transmitted by using only one side of each of the first belt and the second belt. As a result, a robot can be provided that can use a plurality of motors as drive sources without using both sides of the belt for transmitting the driving force.

[0010] According to the present disclosure, a plurality of motors can be used as drive sources without using both sides of the belt for transmitting the driving force. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a perspective view of a humanoid robot according to an embodiment of the present disclosure.

[0012] Figure 2is a block diagram showing the overall structure of a robot joint structure in a humanoid robot.

[0013] Figure 3 is a perspective view schematically showing the structure of a joint portion and a linear motion mechanism.

[0014] Figure 4 is a side view for explaining the structure of the joint portion.

[0015] Figure 5 is a schematic perspective view for explaining the arrangement of the first motor and the second motor.

[0016] Figure 6 is a schematic front view for explaining the arrangement of the first belt and the second belt.

[0017] Figure 7 is a schematic top view for explaining the arrangement of the first motor and the second motor with respect to the thigh link.

[0018] Figure 8 is a side view for explaining a robot joint structure according to a modification of an embodiment of the present disclosure. Detailed Embodiment

[0019] Hereinafter, an embodiment of the present disclosure that embodies the present disclosure will be described based on the drawings.

[0020] Refer to Figures 1 to 7 , the structure of the humanoid robot 100 according to the present embodiment will be described. In addition, the humanoid robot 100 is also referred to as a humanoid robot. Further, the humanoid robot 100 is an example of a robot.

[0021] As Figure 1 shown, the humanoid robot 100 includes a pair of left and right thigh portions 1 and calf portions 2 corresponding to human legs. The thigh portion 1 corresponds to a human thigh. The calf portion 2 corresponds to a human calf. In addition, the structures of the pair of thigh portions 1 are substantially the same, and the structures of the pair of calf portions 2 are substantially the same. Therefore, in the following description, the thigh portion 1 and the calf portion 2 in only one side of the leg will be described.

[0022] The humanoid robot 100 has a thigh link 11 and a calf link 12. The thigh link 11 and the calf link 12 are rod-shaped members in a predetermined part of the humanoid robot 100. Specifically, the thigh link 11 is a member of the thigh portion 1 in the humanoid robot 100. The calf link 12 is a member of the calf portion 2 in the humanoid robot 100. The thigh link 11 and the calf link 12 include, for example, metal members such as aluminum or stainless steel. In addition, the thigh link 11 is an example of a first link member. The calf link 12 is an example of a second link member.

[0023] In addition, the thigh link 11 and the calf link 12 are connected to each other via the joint portion 20. The joint portion 20 is the knee joint in the humanoid robot 100. The thigh link 11 and the calf link 12 rotate relative to each other by the rotation of the joint portion 20. Specifically, the thigh link 11 and the calf link 12 rotate relative to each other in a manner of flexion and extension. By the relative rotation of the thigh link 11 and the calf link 12, the humanoid robot 100 performs bipedal walking.

[0024] As Figure 2 shown, the humanoid robot 100 includes a robot joint structure 100a. The robot joint structure 100a of the present embodiment includes a thigh link 11, a calf link 12, and a joint portion 20. In addition, the robot joint structure 100a includes a linear movement mechanism 30, a first motor 40, a second motor 50, a first belt 60, a second belt 70, an encoder 80, and a control unit 90 to drive the thigh link 11, the calf link 12, and the joint portion 20. Further, the linear movement mechanism 30 is an example of a driving force transmission unit.

[0025] As Figure 3 shown, the linear movement mechanism 30 includes a rotary shaft member 31, a linear movement output member 32, and a pulley 33. For example, the linear movement mechanism 30 has a ball screw mechanism. The rotary shaft member 31 rotates by the rotational drive of the first motor 40 and the second motor 50. The linear movement output member 32 linearly moves by the rotation of the rotary shaft member 31. The pulley 33 rotates by transmitting the rotational drive of the first motor 40 and the second motor 50. Specifically, the pulley 33 is connected to the rotary shaft member 31 and rotates integrally with the rotary shaft member 31. The rotary shaft member 31 is, for example, a rod-shaped member having thread teeth and is disposed inside the linear movement output member 32. The linear movement output member 32 is a rod-shaped member and has a nut member screwed onto the rotary shaft member 31 inside. In the linear movement mechanism 30, by the rotation of the rotary shaft member 31 that rotates integrally with the pulley 33, the rod-shaped linear movement output member 32 linearly moves in the long side direction. That is, in the linear movement mechanism 30, by the rotation of the first motor 40 and the second motor 50, the linear movement output member 32 linearly moves in the long side direction.

[0026] In the linear movement mechanism 30, the end of the linear movement output member 32 is rotatably connected to the joint portion 20. Further, the linear movement mechanism 30 is rotatably disposed relative to the thigh link 11. The linear movement mechanism 30 rotates the joint portion 20 by performing linear movement. The linear movement mechanism 30 relatively rotates the thigh link 11 and the calf link 12 by the rotation of the rotary shaft member 31. That is, by the linear movement of the linear movement output member 32, the linear movement mechanism 30 rotates the joint portion 20 and relatively rotates the thigh link 11 and the calf link 12. In other words, the linear movement mechanism 30 is a driving force transmission mechanism that relatively rotates the thigh link 11 and the calf link 12 by transmitting the driving force based on the rotation of the first motor 40 and the second motor 50. Further, the rotary shaft member 31 of the linear movement mechanism 30 is disposed along the rod-shaped thigh link 11, which is a member of the thigh portion 1, in order to rotate the joint portion 20, which is a knee joint. Further, the linear movement mechanism 30 is disposed on the opposite side of the rotation direction when the thigh link 11 and the calf link 12 rotate in a mutually flexed manner. That is, the linear movement mechanism 30 is disposed on the front side of the thigh portion 1 in the humanoid robot 100.

[0027] The joint portion 20 includes two links 21 and 22. The links 21 and 22 are disposed to cross each other in a state where the thigh link 11 and the calf link 12 are extended. The links 21 and 22 connect the thigh link 11 and the calf link 12 to each other, respectively. Further, the link 21 is connected to the end of the linear movement output member 32 of the linear movement mechanism 30. The link 21 has a V shape when viewed from the left-right direction, i.e., the side, of the humanoid robot 100.

[0028] As Figure 4 shown, specifically, the link 21 is rotatably connected to the end of the linear movement output member 32 of the linear movement mechanism 30 via the connecting portion 21a. Further, the link 21 is rotatably connected to the thigh link 11 via the connecting portion 21b. The link 21 is rotatably connected to the calf link 12 via the connecting portion 21c. Similarly, the link 22 is rotatably connected to the thigh link 11 via the connecting portion 22a. The link 22 is rotatably connected to the calf link 12 via the connecting portion 22b. The links 21 and 22 are connected so as to sandwich the thigh link 11 and the calf link 12 from both sides in the left-right direction, respectively. Further, the end portion of the thigh link 11 on the calf link 12 side and the end portion of the calf link 12 on the thigh link 11 side each have an L shape. Moreover, the connecting portion 21b and the connecting portion 22a are disposed at the L-shaped end portion of the thigh link 11 on the calf link 12 side. Similarly, the connecting portion 21c and the connecting portion 22b are disposed at the L-shaped end portion of the calf link 12 on the thigh link 11 side.

[0029] In addition, the portion of the linear movement mechanism 30 on the pulley 33 side is connected to the thigh link 11 via a support member 34. The linear movement mechanism 30 is configured to be rotatable about a rotation axis 34a with respect to the thigh link 11. In the joint structure constituted by the linear movement mechanism 30, the thigh link 11, the calf link 12, the link 21, and the link 22, the linear movement output member 32 of the linear movement mechanism 30 moves linearly, so that the link 21 rotates. When the link 21 rotates, the calf link 12 connected to the connection portion 21c rotates relative to the thigh link 11 while being constrained by the link 22. That is, the calf link 12 rotates relative to the thigh link 11 by rotating while changing its orientation by being connected to the link 22 and by the movement of the link 21.

[0030] 〈Structure of motor and belt〉

[0031] As Figure 5 shown, the first motor 40 has a first motor rotation shaft 41 and a pulley 42. The second motor 50 has a second motor rotation shaft 51 and a pulley 52. In the present embodiment, the first motor 40 and the second motor 50 are provided independently of each other. In the first motor 40, the pulley 42 is connected to the first motor rotation shaft 41 and rotates integrally with the first motor rotation shaft 41. In the second motor 50, the pulley 52 is connected to the second motor rotation shaft 51 and rotates integrally with the second motor rotation shaft 51. The first motor rotation shaft 41 and the second motor rotation shaft 51 are the rotation shafts of the first motor 40 and the second motor 50, respectively. The first motor 40 and the second motor 50 are servo motors that rotate by feedback control performed by the control unit 90. Moreover, the first motor 40 and the second motor 50 serve as drive sources for relatively rotating the thigh link 11 and the calf link 12. In addition, the first motor 40 and the second motor 50 are arranged with rotation shafts along the rod-shaped thigh link 11. The first motor rotation shaft 41 and the second motor rotation shaft 51 are respectively arranged substantially parallel to the rotation shaft member 31 of the linear movement mechanism 30. Further, the first motor 40 and the second motor 50 rotate relative to the thigh link 11 integrally with the linear movement mechanism 30. Specifically, the first motor 40, the second motor 50, and the linear movement mechanism 30 are arranged on a common fixing member 35.

[0032] The encoder 80 detects the rotational speed of the first motor 40. The encoder 80 outputs a detection signal indicating the rotational speed of the first motor 40 to the control unit 90. The encoder 80 is arranged, for example, on the first motor 40. The encoder 80 detects the rotational speed of the first motor 40, for example, by detecting a change in the magnetic field caused by rotation.

[0033] The control unit 90 controls the rotational drive of the first motor 40 based on the detection signal from the encoder 80. The control unit 90 outputs a control signal for controlling the rotational drive of the first motor 40 to a motor driver (not shown) by, for example, feedback control based on the detection signal from the encoder 80. The control signal is, for example, a pulse signal. The current supplied to the first motor 40 is controlled by this control signal. Moreover, in the present embodiment, the control unit 90 controls the rotational drives of both the first motor 40 and the second motor 50 by using the control signal for controlling the first motor 40, so that the second motor 50 is driven in a slave manner with respect to the first motor 40. That is, the control unit 90 performs control so that the rotations of the first motor 40 and the second motor 50 are synchronized. The first motor 40 and the second motor 50 are controlled to rotate in the same rotational direction at the same rotational speed at the same time. The control unit 90 is disposed, for example, in the main body portion of the humanoid robot 100. In addition, the control unit 90 is a computer including arithmetic devices such as a CPU (Central Processing Unit) and an FPGA (Field Programmable Gate Array), and a storage device such as a flash memory.

[0034] The first belt 60 transmits the rotational drive of the first motor 40 to the rotary shaft member 31. The second belt 70 transmits the rotational drive of the second motor 50 to the rotary shaft member 31. The first belt 60 and the second belt 70 are provided independently of each other. The first belt 60 is stretched between the pulley 42 of the first motor 40 and the pulley 33 of the linear movement mechanism 30. The second belt 70 is stretched between the pulley 52 of the second motor 50 and the pulley 33 of the linear movement mechanism 30. That is, the first belt 60 transmits the rotation of the pulley 42 of the first motor 40 to the pulley 33 of the linear movement mechanism 30. The second belt 70 transmits the rotation of the pulley 52 of the second motor 50 to the pulley 33 of the linear movement mechanism 30. In addition, the pulley 33, the pulley 42, and the pulley 52 are toothed pulleys. Moreover, the first belt 60 and the second belt 70 have a plurality of tooth portions on the inner side. On the other hand, the first belt 60 and the second belt 70 do not have tooth portions on the outer side. In addition, the outer diameter of the pulley 33 is smaller and the number of teeth is smaller than those of the pulley 42 and the pulley 52. Therefore, the rotational speed of the pulley 33 is higher than that of the pulley 42 and the pulley 52. In addition, the first belt 60 is not stretched over a rolling wheel such as an idler pulley for adjusting the tension or the moving direction of the belt. Similarly, the second belt 70 is not stretched over a rolling wheel such as an idler pulley for adjusting the tension or the moving direction of the belt.

[0035] As Figure 6As shown, the pulley 42 is disposed on the upper side, i.e., the Z1 direction side, with respect to the main body portion of the first motor 40. Further, the pulley 52 is disposed on the upper side, i.e., the Z1 direction side, with respect to the main body portion of the second motor 50. Therefore, each of the pulley 33, the pulley 42, and the pulley 52 is disposed on the Z1 direction side. Moreover, in the present embodiment, the first belt 60 and the second belt 70 are installed in a state where they are staggered so as to be adjacent to each other in the direction in which the rotary shaft member 31 extends, i.e., the Z direction, at the pulley 33. Specifically, the first belt 60 is disposed on the upper side, i.e., the end side of the rotary shaft member 31, in the Z1 direction with respect to the second belt 70. Since the first belt 60 is disposed on the upper side, i.e., the Z1 direction side, with respect to the second belt 70, the distance D1 from the pulley 42 to the fixing member 35 is greater than the distance D2 from the pulley 52 to the fixing member 35.

[0036] Here, when viewed from the direction in which the rotary shaft member 31 is disposed with respect to the rod-shaped thigh link 11, the first motor 40 and the second motor 50 are respectively disposed on one side and the other side in the short side direction of the thigh link 11. That is, when viewed from the front side, i.e., the Y1 direction side, of the humanoid robot 100 in a state where the thigh link 11 and the calf link 12 are extended, the first motor 40 is disposed on the X1 direction side with respect to the thigh link 11. Further, when viewed from the front side of the humanoid robot 100 in a state where the thigh link 11 and the calf link 12 are extended, the second motor 50 is disposed on the X2 direction side with respect to the thigh link 11. In other words, when viewed from the Y1 direction side, the first motor 40 and the second motor 50 are disposed so as to sandwich the thigh link 11 therebetween. In addition, the X1 direction side and the X2 direction side are respectively examples of one side and the other side in the short side direction.

[0037] As Figure 7 shown, the first motor 40 is disposed on the X1 direction side such that the first motor rotary shaft 41 is located at a position closer to the thigh link 11 than the rotary shaft member 31 of the linear motion mechanism 30. Further, the second motor 50 is disposed on the X2 direction side such that the second motor rotary shaft 51 is located at a position closer to the thigh link 11 than the rotary shaft member 31 of the linear motion mechanism 30. That is, the first motor rotary shaft 41 of the first motor 40 and the second motor rotary shaft 51 of the second motor 50 are located at positions on the back side, i.e., the Y2 direction side, of the humanoid robot 100 in a state where the thigh link 11 and the calf link 12 are extended, closer to the thigh link 11 than the rotary shaft member 31 of the linear motion mechanism 30. In addition, the positions of the first motor 40 and the second motor 50 in the Y direction are substantially the same positions. In the robot joint structure 100a of the humanoid robot 100, when viewed from the long side direction, i.e., the Z direction, of the rod-shaped thigh link 11, the first motor 40 and the second motor 50 are disposed such that a V shape is formed by the first belt 60 and the second belt 70.

[0038] [Effects of the Present Embodiment]

[0039] In the present embodiment, as described above, the robotic joint structure 100a of the humanoid robot 100 serving as a robot includes: a first belt 60 that transmits the rotational drive of the first motor 40 to the rotary shaft member 31; and a second belt 70 that transmits the rotational drive of the second motor 50 to the rotary shaft member 31. Thus, even when multiple motors, namely the first motor 40 and the second motor 50, are used as drive sources, the driving force can be transmitted by using only one side of each of the first belt 60 and the second belt 70. As a result, multiple motors can be used as drive sources without using both sides of the belts for transmitting the driving force.

[0040] In addition, in the present embodiment, as described above, the robotic joint structure 100a of the humanoid robot 100 serving as a robot includes a linear movement mechanism 30. The linear movement mechanism 30 has a rotary shaft member 31 and a linear movement output member 32 that linearly moves by the rotation of the rotary shaft member 31, and the linear movement of the linear movement output member 32 causes the thigh link 11 serving as the first link member and the calf link 12 serving as the second link member to rotate relative to each other. The thigh link 11 and the calf link 12 are rod-shaped members in a prescribed part of the humanoid robot 100. The rotary shaft member 31 of the linear movement mechanism 30 serving as the driving force transmission part is arranged along the rod-shaped thigh link 11. The first motor 40 and the second motor 50 are arranged such that their rotary shafts are along the rod-shaped thigh link 11. Thus, even when multiple motors, namely the first motor 40 and the second motor 50, are used as drive sources for the relative rotation of the rod-shaped thigh link 11 and the calf link 12 in the humanoid robot 100, multiple motors can be used as drive sources without using both sides of the independently provided first belt 60 and second belt 70. In addition, the rotary shaft member 31 of the linear movement mechanism 30 and the rotary shafts of the first motor 40 and the second motor 50 are arranged along the rod-shaped thigh link 11 in the humanoid robot 100, so that the extending directions of the rotary shaft member 31 and the rotary shafts of the first motor 40 and the second motor 50 can be made to coincide. Therefore, compared with the case where the relative orientations of the rotary shaft member 31 and the rotary shafts of the first motor 40 and the second motor 50 are different, there is no need to provide components for changing the moving directions of the first belt 60 and the second belt 70 in order to install the first belt 60 and the second belt 70 between shafts with different orientations, and thus the complication of the structure of the humanoid robot 100 can be suppressed.

[0041] In addition, in the present embodiment, as described above, the thigh link 11 as the first link member is a rod-shaped member. The rotary shaft member 31 of the linear motion mechanism 30 as the driving force transmission unit is arranged along the rod-shaped thigh link 11. When viewed from the front side, which is the direction in which the rotary shaft member 31 is arranged with respect to the rod-shaped thigh link 11, the first motor 40 and the second motor 50 are respectively arranged on one side and the other side in the short side direction of the thigh link 11. Thus, with respect to the rod-shaped thigh link 11, the first motor 40 and the second motor 50 are respectively arranged on one side and the other side in the short side direction. Therefore, compared with the case where the first motor 40 and the second motor 50 are both arranged on either one side in the short side direction, the arrangement bias to one side with respect to the rod-shaped thigh link 11 can be suppressed. Therefore, when multiple motors are used as the drive source without using both sides of the belt, the balance of the movement of the humanoid robot 100 caused by the arrangement bias to one side with respect to the rod-shaped thigh link 11 can be suppressed.

[0042] In addition, in the present embodiment, as described above, the first motor 40 has a first motor rotary shaft 41 and is arranged on one side in the short side direction such that the first motor rotary shaft 41 is located closer to the thigh link 11 as the first link member than the rotary shaft member 31 of the linear motion mechanism 30 as the driving force transmission unit. The second motor 50 has a second motor rotary shaft 51 and is arranged on the other side in the short side direction such that the second motor rotary shaft 51 is located closer to the thigh link 11 than the rotary shaft member 31 of the linear motion mechanism 30. Thus, with respect to the rotary shaft member 31 of the linear motion mechanism 30 arranged along the rod-shaped thigh link 11, the first motor rotary shaft 41 of the first motor 40 and the second motor rotary shaft 51 of the second motor 50 are arranged on the thigh link 11 side. Therefore, the linear motion mechanism 30, the first motor 40, and the second motor 50 can be arranged along the periphery of the thigh link 11. Therefore, when multiple motors are used as the drive source without using both sides of the belt, the size of the structure around the thigh link 11 can be suppressed from increasing, and thus the size of the structure of the humanoid robot 100 can be suppressed from increasing.

[0043] In addition, in the present embodiment, as described above, the linear motion mechanism 30 as the driving force transmission unit includes a pulley 33 around which the first belt 60 and the second belt 70 are respectively stretched and which rotates integrally with the rotary shaft member 31. The first belt 60 and the second belt 70 are stretched around the pulley 33 in a state where they are staggered so as to be adjacent to each other in the direction in which the rotary shaft member 31 extends. Thus, since the first belt 60 and the second belt 70 are stretched around the pulley 33 in a state where they are staggered and adjacent to each other, an increase in the size in the direction in which the rotary shaft member 31 extends can be suppressed. Therefore, when multiple motors are used as the drive source without using both sides of the belt, the size of the structure of the humanoid robot 100 can be suppressed from increasing.

[0044] In addition, in the present embodiment, as described above, the thigh link 11 as the first link member and the calf link 12 as the second link member are rod-shaped members that rotate relative to each other in a manner of flexion and extension. The linear motion mechanism 30 as the driving force transmission unit is disposed on the opposite side of the rotational direction when the thigh link 11 and the calf link 12 rotate in a manner of flexion with respect to each other. Thus, when the linear motion mechanism 30 is disposed on the inner side of the rotational direction in the case of rotation in a manner of flexion, it can be considered that the configuration of the linear motion mechanism 30 and the configurations of the first motor 40 and the second motor 50 that are the driving sources of the linear motion mechanism 30 may sometimes hinder flexion due to the configuration of the linear motion mechanism 30 itself. In this case, it is considered difficult to increase the rotational angle during flexion of the thigh link 11 and the calf link 12. In contrast, in the present embodiment, by disposing the linear motion mechanism 30 on the opposite side of the rotational direction when the thigh link 11 and the calf link 12 rotate in a manner of flexion with respect to each other, it is possible to increase the rotational angle during flexion when using a plurality of motors as driving sources without using both sides of the belt.

[0045] In addition, in the present embodiment, as described above, the thigh link 11 as the first link member is a member of the thigh portion 1 in the humanoid robot 100. The calf link 12 as the second link member is a member of the calf portion 2 in the humanoid robot 100. The rotation shaft member 31 of the linear motion mechanism 30 as the driving force transmission unit is disposed along the rod-shaped thigh link 11 that is a member of the thigh portion 1 in order to rotate the joint portion 20 as the knee joint. Here, in the flexion and extension motions of the thigh portion 1 and the calf portion 2 of the humanoid robot 100, it is necessary to perform the motions while supporting the entire weight of the humanoid robot 100, and thus sometimes a plurality of motors are used to obtain the torque required for the motions. Therefore, by using the independently provided first belt 60 and the second belt 70 to transmit the driving forces of the plurality of motors, that is, the first motor 40 and the second motor 50, it is possible to effectively use a plurality of motors as driving sources without using both sides of the belt that transmits the driving force in the flexion and extension motions of the thigh portion 1 and the calf portion 2 of the humanoid robot 100.

[0046] In addition, in the present embodiment, as described above, the robot joint structure 100a of the humanoid robot 100 includes: an encoder 80 that detects the rotational speed of the first motor 40; and a control unit 90 that controls the rotational drive of the first motor 40 based on the detection signal from the encoder 80. The control unit 90 controls the rotational drives of both the first motor 40 and the second motor 50 by using a control signal for controlling the first motor 40, so that the second motor 50 is driven in a slave manner with respect to the first motor 40. Thus, by using a common control signal to control both the first motor 40 and the second motor 50, it is possible to control the rotation in a state where the rotational drives of the first motor 40 and the second motor 50 are accurately synchronized without using both sides of a belt and using a plurality of motors as drive sources.

[0047] [Modification Example]

[0048] Furthermore, all points of the embodiments disclosed this time should be considered as illustrative and not restrictive. The scope of the present disclosure is not defined by the description of the above embodiments, but is represented by the claims, and also includes meanings equivalent to the claims and all changes (modification examples) within the scope.

[0049] For example, in the above embodiment, an example in which the joint portion 20 has two link members, i.e., the link 21 and the link 22, is shown, but the present disclosure is not limited thereto. In the present disclosure, the joint portion may not have a link member. For example, as in the robot joint structure according to the modification example shown in Figure 8 , the first link member 211, which is a component of the thigh portion in the humanoid robot, and the second link member 212, which is a component of the calf portion, may be directly connected via a joint portion 220 that is a shaft core component serving as a rotation axis. In this case, the linear movement mechanism 230 is directly connected to the second link member 212 in a rotatable manner. The transmission of the driving force to the linear movement mechanism 230 is the same as in the above embodiment. That is, the driving forces of the first motor 40 and the second motor 50 are respectively transmitted to the linear movement mechanism 230 via the first belt 60 and the second belt 70. In addition, the joint portion may include only one link member. Furthermore, the linear movement mechanism 230 is an example of a driving force transmission unit.

[0050] In addition, in the above-described embodiment, an example of the robot joint structure 100a in which the thigh link 11, which is the first link member of the leg of the humanoid robot 100 and serves as the thigh portion 1, and the calf link 12, which is the second link member of the calf portion 2, rotate relative to each other is shown. However, the present disclosure is not limited thereto. In the present disclosure, the robot joint structure may be configured such that the first link member and the second link member in a robot other than a humanoid rotate relative to each other. For example, the first link member and the second link member may be rotated relative to each other in the leg of a quadruped robot. In addition, the first link member and the second link member that are connected to each other by the elbow joint of the arm rather than the leg of the humanoid robot may be rotated relative to each other.

[0051] In addition, in the above-described embodiment, an example in which the first motor 40 and the second motor 50 are respectively disposed on one side and the other side in the short side direction of the thigh link 11, which is the rod-shaped first link member, is shown. However, the present disclosure is not limited thereto. In the present disclosure, both the first motor and the second motor may be disposed on either one side or the other side in the short side direction of the first link member. In addition, in addition to the first motor and the second motor, a third motor may also be disposed. That is, three or more motors may be disposed.

[0052] In addition, in the above-described embodiment, an example in which the first motor rotation shaft 41 of the first motor 40 and the second motor rotation shaft 51 of the second motor 50 are disposed at a position closer to the thigh link 11, which is the first link member, than the rotation shaft member 31 of the linear motion mechanism 30, which is the driving force transmission unit, is shown. However, the present disclosure is not limited thereto. In the present disclosure, the first motor rotation shaft of the first motor, the second motor rotation shaft of the second motor, and the rotation shaft member of the driving force transmission unit may also be linearly arranged side by side in the left-right direction when viewed from the axial direction.

[0053] In addition, in the above-described embodiment, an example in which the first belt 60 and the second belt 70 are arranged and strung adjacent to each other in the pulley 33 connected to the rotation shaft member 31 is shown. However, the present disclosure is not limited thereto. In the present disclosure, the first belt and the second belt may also be strung in a state of being separated from each other with respect to the pulley.

[0054] In addition, in the above-described embodiment, an example in which the linear motion mechanism 30, which is the driving force transmission unit, is disposed on the opposite side of the rotation direction when the thigh link 11, which is the first link member, and the calf link 12, which is the second link member, rotate in a mutually bent manner is shown. However, the present disclosure is not limited thereto. In the present disclosure, the driving force transmission unit may also be disposed on the positive direction side of the rotation direction when the first link member and the second link member rotate in a mutually bent manner.

[0055] In addition, in the above-described embodiment, an example is shown in which the rotational driving of both the first motor 40 and the second motor 50 is controlled by a control signal for controlling the first motor 40 based on a detection signal from an encoder 80 that detects the rotational speed of the first motor 40. However, the present disclosure is not limited thereto. In the present disclosure, it is also possible to drive the second motor in a slave manner with respect to the first motor by respectively disposing encoders on the first motor and the second motor and controlling the detection signal from the encoder of the second motor to follow the detection signal from the encoder of the first motor.

[0056] In addition, in the above-described embodiment, an example is shown in which a linear movement mechanism 30 as a driving force transmission unit transmits a driving force for relatively rotating a thigh link 11 as a first link member and a calf link 12 as a second link member by a linear movement of a linear movement output member 32. However, the present disclosure is not limited thereto. In the present disclosure, the driving force transmission unit may be a rotational transmission mechanism instead of a linear movement mechanism including a linear movement output member. That is, the driving force transmission unit may relatively rotate the first link member and the second link member by transmitting the rotational driving force of the first motor and the second motor as a rotational movement.

[0057] The functions of the elements disclosed in this specification can be executed using a circuit or a processing circuit including a general-purpose processor, a dedicated processor, an integrated circuit, an ASIC (Application Specific Integrated Circuits), a conventional circuit, and / or a combination thereof that are configured or programmed to execute the disclosed functions. Since a processor includes transistors and other circuits, it can be regarded as a processing circuit or a circuit. In the present disclosure, a circuit, a unit, or an organization is hardware that executes the listed functions, or is hardware programmed to execute the listed functions. The hardware may be the hardware disclosed in this specification, or may also be other known hardware configured or programmed to execute the listed functions. When the hardware is a processor that is considered to be a type of circuit, the circuit, the organization, or the unit is a combination of hardware and software, and the software is used for the structure of the hardware and / or the processor.

[0058] [Mode]

[0059] Those skilled in the art should understand that the above-described exemplary embodiments are specific examples of the following modes.

[0060] (Mode 1) A robot joint structure, wherein,

[0061] The above robot joint structure includes:

[0062] A first link member and a second link member, which are connected to each other via a joint portion;

[0063] The first motor and the second motor serve as drive sources for relatively rotating the first link member and the second link member;

[0064] The driving force transmission unit includes a rotating shaft member that rotates by the rotational drive of the first motor and the second motor, and relatively rotates the first link member and the second link member by the rotation of the rotating shaft member;

[0065] The first belt transmits the rotational drive of the first motor to the rotating shaft member; and

[0066] The second belt transmits the rotational drive of the second motor to the rotating shaft member.

[0067] (Mode 2) According to the robot joint structure described in Mode 1, wherein

[0068] The driving force transmission unit includes a linear movement mechanism, which has the rotating shaft member and a linear movement output member that linearly moves by the rotation of the rotating shaft member, and relatively rotates the first link member and the second link member by the linear movement of the linear movement output member,

[0069] The first link member and the second link member are rod-shaped members in a specified part of the humanoid robot,

[0070] The rotating shaft member of the driving force transmission unit is arranged along the rod-shaped first link member,

[0071] The first motor and the second motor are arranged with their rotation axes along the rod-shaped first link member.

[0072] (Mode 3) According to the robot joint structure described in Mode 1 or 2, wherein

[0073] The first link member is a rod-shaped member,

[0074] The rotating shaft member of the driving force transmission unit is arranged along the rod-shaped first link member,

[0075] When viewed from the direction in which the rotating shaft member is arranged relative to the rod-shaped first link member, the first motor and the second motor are respectively arranged on one side and the other side in the short side direction of the first link member.

[0076] (Mode 4) According to the robot joint structure described in Mode 3, wherein

[0077] The first motor has a first motor rotating shaft, and is arranged on one side in the short-side direction so that the first motor rotating shaft is located closer to the first link member than the rotating shaft member of the driving force transmission portion.

[0078] The second motor includes a second motor rotating shaft and is arranged on the other side in the short-side direction so that the second motor rotating shaft is located closer to the first link member than the rotating shaft member of the driving force transmission portion.

[0079] (Mode 5) The robot joint structure according to any one of Modes 1 to 4, wherein:

[0080] The driving force transmission unit includes a pulley on which the first belt and the second belt are respectively stretched and which rotates integrally with the rotating shaft member.

[0081] The first belt and the second belt are stretched over the pulleys in a staggered state so as to be adjacent to each other in the direction in which the rotating shaft member extends.

[0082] (Mode 6) The robot joint structure according to any one of Modes 1 to 5, wherein:

[0083] The first link member and the second link member are rod-shaped members that rotate relative to each other in a manner of bending and stretching.

[0084] The driving force transmission portion is arranged on the opposite side of the rotation direction when the first link member and the second link member rotate in a manner of bending relative to each other.

[0085] (Method 7) The robot joint structure according to method 2, wherein:

[0086] The first link member is a member of the thigh portion of the humanoid robot.

[0087] The second link member is a member of the lower leg portion of the humanoid robot.

[0088] The rotating shaft member of the driving force transmission portion is arranged along the rod-shaped first link member serving as a member of the thigh portion in order to rotate the joint portion serving as the knee joint.

[0089] (Mode 8) The robot joint structure according to any one of Modes 1 to 7, wherein:

[0090] The above robot joint structure also has:

[0091] an encoder for detecting the rotational speed of the first motor; and

[0092] The control unit controls the rotational drive of the first motor based on the detection signal from the above-mentioned encoder.

[0093] The control unit controls the rotational drives of both the first motor and the second motor by using a control signal for controlling the first motor, so that the second motor is driven in a slave manner with respect to the first motor.

[0094] (Mode 9) A robot, wherein

[0095] The robot includes:

[0096] A first link member and a second link member, which are connected to each other via a joint portion;

[0097] A first motor and a second motor, which serve as drive sources for relatively rotating the first link member and the second link member;

[0098] A driving force transmission unit includes a rotating shaft member that rotates by the rotational drives of the first motor and the second motor, and relatively rotates the first link member and the second link member by the rotation of the rotating shaft member;

[0099] A first belt that transmits the rotational drive of the first motor to the rotating shaft member; and

[0100] A second belt that transmits the rotational drive of the second motor to the rotating shaft member.

Claims

1. A robot joint structure, wherein, the robot joint structure includes: a first link member and a second link member, which are connected to each other via a joint portion; a first motor and a second motor, which serve as driving sources for relatively rotating the first link member and the second link member; a driving force transmission portion, which includes a rotating shaft member that rotates by the rotational drive of the first motor and the second motor, and relatively rotates the first link member and the second link member by the rotation of the rotating shaft member; a first belt, which transmits the rotational drive of the first motor to the rotating shaft member; and a second belt, which transmits the rotational drive of the second motor to the rotating shaft member.

2. The robot joint structure according to claim 1, wherein, the driving force transmission portion includes a linear movement mechanism, which has the rotating shaft member and a linear movement output member that linearly moves by the rotation of the rotating shaft member, and relatively rotates the first link member and the second link member by the linear movement of the linear movement output member, the first link member and the second link member are rod-shaped members in a specified part of a humanoid robot, the rotating shaft member of the driving force transmission portion is arranged along the rod-shaped first link member, the first motor and the second motor are arranged with their rotation axes along the rod-shaped first link member.

3. The robot joint structure according to claim 1, wherein, the first link member is a rod-shaped member, the rotating shaft member of the driving force transmission portion is arranged along the rod-shaped first link member, when observed from the direction in which the rotating shaft member is arranged relative to the rod-shaped first link member, the first motor and the second motor are respectively arranged on one side and the other side in the short side direction of the first link member.

4. The robot joint structure according to claim 3, wherein, the first motor has a first motor rotating shaft, and is arranged on one side in the short side direction such that the first motor rotating shaft is located closer to the first link member than the rotating shaft member of the driving force transmission portion, the second motor has a second motor rotating shaft, and is arranged on the other side in the short side direction such that the second motor rotating shaft is located closer to the first link member than the rotating shaft member of the driving force transmission portion.

5. The robot joint structure according to claim 1, wherein, the driving force transmission portion includes a pulley, on which the first belt and the second belt are respectively mounted and rotate integrally with the rotating shaft member, the first belt and the second belt are mounted on the pulley in a state where they are staggered so as to be adjacent to each other in the direction in which the rotating shaft member extends.

6. The robot joint structure according to claim 1, wherein, the first link member and the second link member are rod-shaped members, and relatively rotate in a manner of bending and extending with respect to each other. The driving force transmission part is arranged on the opposite side of the rotation direction when the first link member and the second link member rotate in a mutually buckling manner.

7. The robot joint structure according to claim 2, wherein the first link member is a member of the thigh part in the humanoid robot, the second link member is a member of the calf part in the humanoid robot, the rotary shaft member of the driving force transmission part is arranged in a manner along the rod-shaped first link member which is the member of the thigh part in order to rotate the joint part which is the knee joint.

8. The robot joint structure according to claim 1, wherein the robot joint structure further includes: an encoder for detecting the rotational speed of the first motor; and a control part for controlling the rotational drive of the first motor based on the detection signal from the encoder, the control part controls the rotational drives of both the first motor and the second motor by using a control signal for controlling the first motor, so as to drive the second motor in a slave manner with respect to the first motor.

9. A robot, wherein the robot includes: a first link member and a second link member which are connected to each other via a joint part; a first motor and a second motor which serve as driving sources for relatively rotating the first link member and the second link member; a driving force transmission part including a rotary shaft member that rotates by the rotational drives of the first motor and the second motor, and relatively rotates the first link member and the second link member by the rotation of the rotary shaft member; a first belt for transmitting the rotational drive of the first motor to the rotary shaft member; and a second belt for transmitting the rotational drive of the second motor to the rotary shaft member.

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