JP2013091146A - Articular structure of robot and humanoid robot with the incorporated articular structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an articular structure of a robot which enables size reduction and in which backlash can be eliminated.SOLUTION: The articular structure of the robot includes: a first member 31; a rotary output shaft 32 rotatably supported by the first member 31 around an axis A1 and connectable to the second member 41; and first and second linearly moving actuator 24a, 24b having body parts 62a, 62b and shaft parts 63a, 63b linearly moving with respect to the body parts 62a, 62b. The body parts 62a, 62b of the first and second linearly moving actuators 24a, 24b are rotatably supported by the first member 31, and the shaft parts 63a, 63b are connected to the rotary output shaft 32. By extending/retracting the first and second linearly moving actuators 24a, 24b, the rotary output shaft 32 is relatively rotated around the axis A1 with respect to the first member 31.

Description

  The present invention relates to a joint structure of a robot and a humanoid robot incorporating the joint structure, and more particularly to a joint structure of a robot suitable for use in a shoulder joint of a humanoid robot.

  In recent years, research and development of not only industrial robots but also robots that have various roles for consumer use have been actively conducted. Among robots, humanoid robots (humanoid robots) that can stand upright are expected to replace human behavior. Such a humanoid robot has joints in the leg portion, arm portion, neck portion, and the like, and can operate close to a human.

  By the way, there are various types of robot joints ranging from one having one degree of freedom to three or more degrees of freedom. The degree of freedom is the number of directions that can freely move. For example, the degree of freedom of a joint that can rotate only around the pitch axis is 1, and the degree of freedom of the joint that can rotate around two axes, the pitch axis and the yaw axis. The degree is 2, and the degree of freedom of the joint that can rotate around the pitch axis, the roll axis, and the yaw axis is 3. There are various types of shoulder joints for humanoid robots ranging from one having one degree of freedom to three or more degrees of freedom.

  In a conventional joint structure of a robot, in order to realize a joint with one degree of freedom of rotation, a servo motor having a rotation axis is generally used. In order to realize a joint having two or more degrees of freedom of rotation, it is common to combine two or more servo motors (see, for example, Patent Document 1).

JP 2008-188699 A

  However, in a joint structure using a conventional rotary servomotor, the servomotor receives a rotational moment, so the load on the servomotor increases, the servomotor becomes larger, and therefore the joint structure is reduced in size. There is a problem that it becomes difficult. In particular, when the joint structure of a conventional robot is used as the shoulder joint of a humanoid robot, there is a problem that it is difficult to realize a thin shoulder or arm like a human.

  In addition, when a reduction gear is provided in combination with the servo motor to reduce the size of the servo motor, the driven structure such as the arm swings due to the backlash of the reduction gear, and the joint structure is not stable. There are challenges.

  The present invention solves the above-mentioned problems of the joint structure of a conventional robot. The joint structure of the robot can be reduced in size and can eliminate rattling of the joint structure, and a humanoid incorporating the joint structure of the robot The purpose is to provide a robot.

  In order to solve the above-described problem, one aspect of the present invention is a joint structure of a robot that rotates a second member relative to a first member around an axis of a rotation output shaft. And a rotation output shaft that is supported by the first member so as to be rotatable about an axis, and that can be coupled to the second member, a main body portion, and a shaft portion that linearly moves with respect to the main body portion. One of the part and the shaft part is supported by the first member so as to be rotatable around an axis parallel to the axis of the rotation output shaft, and the other of the body part and the shaft part is connected to the rotation output shaft The first and second linear motion actuators, and by expanding and contracting the first and second linear motion actuators, the rotational output shaft is made relative to the first member around an axis. It is a joint structure of a robot that rotates in an automatic manner.

  According to one aspect of the present invention, when rotating the rotation output shaft relative to the first member, the first and second linear actuators are expanded and contracted. Compared to the joint structure used, several times the force can be generated. Conversely, the first and second linear actuators can be reduced in size after obtaining the necessary force. Further, since the rotation output shaft and the first and second linear actuators are provided on the first member and the first member and the second member are not connected by a link or the like, the joint structure can be reduced in size. Further, since one rotary output shaft is rotated by two linear actuators, the first and second linear actuators can be operated by shifting them so that the backs inside the first and second linear actuators can be moved. It becomes possible to eliminate the rattling of the joint structure due to the clearance generated in the lash, the bearing and the like.

The front view of the humanoid robot in which the joint structure of the robot of one embodiment of the present invention is incorporated Right side view of the above humanoid robot Front view of the upper body of the above humanoid robot A perspective view of the right shoulder joint of the humanoid robot The perspective view of the joint structure of the robot of this embodiment Detailed view of the joint structure of the robot of the present embodiment ((a) in the figure shows a side view, and (b) in the figure is a sectional view taken along the line bb in (a)). Block diagram of a control system for controlling the first and second linear actuators Operation diagram of joint structure of robot of this embodiment The schematic diagram which shows an example of the rattling of the joint structure of the robot of this embodiment

  A robot joint structure according to an embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a front view showing an overall configuration of a humanoid robot in which the joint structure of the robot according to the present embodiment is incorporated. FIG. 2 is a right side view of the humanoid robot. In the present embodiment, the left and right are the left and right viewed from the humanoid robot side shown in the figure. Also, assuming that the advancing direction of the humanoid robot is the x axis positive direction, the left hand direction as viewed from the humanoid robot is the y axis positive direction, and the upper part of the humanoid robot is the z axis positive direction, the x axis is the roll axis and the y axis is The pitch axis and z axis are the yaw axes. Then, rotation around the x axis is roll, rotation around the y axis is pitch, and rotation around the z axis is yaw.

  The humanoid robot 10 is installed above the body part 11, with two leg parts 12 installed below the body part 11, two arm parts 13 installed on the upper left and right side surfaces of the body part 11, and the body part 11. It is composed of a single head 14 that is made to operate like a human.

  The two arm portions 13 are rounded to the body portion 11 via shoulder joints, and can be freely rotated around the body portion 11. Each arm portion 13 includes an upper arm portion 13c closer to the shoulder and a lower arm portion 13b closer to the hand portion 13a with the elbow as a boundary. A hand portion 13 a is installed at the tip of the lower arm portion 13 b via a wrist joint 28. By using the hand portion 13a, it is possible to grasp or pick an object.

  The humanoid robot 10 is a biped walking robot, and walks with a balance between two legs like a human. Each leg portion 12 is connected to the pelvis of the trunk portion 11 via the hip joint 16. The hip joint 16 rotates each leg 12 about the yaw axis, the pitch axis, and the roll axis.

  A thigh 17 a is connected to the hip joint 16. A knee joint 18 is provided below the thigh 17a. A shin portion 17 b is connected to the lower side of the knee joint 18. An ankle joint 19 is provided under the shin part 17b. Under the ankle joint 19, a foot 20 that contacts the walking road surface is connected.

  A CCD camera 15 is installed on each of the head 14 and the body 11. The CCD camera 15 can collect the situation around the humanoid robot 10 as image data.

  This humanoid robot 10 is a robot configured to be remotely operable, and when the operator operates an operation manipulator (not shown) located at a remote position, the humanoid robot 10 performs an operation according to the movement of the operation manipulator. It can be executed. Therefore, the operator can grasp the situation around the humanoid robot 10 while staying at a remote place via the wireless communication means such as the Internet line or the CCD camera 15 installed in the humanoid robot 10. The type robot 10 can be operated.

  3 shows a front view of the upper half of the humanoid robot with the cover removed, and FIG. 4 shows a perspective view of the right shoulder joint. The robot joint structures 22 and 23 according to an embodiment of the present invention are used as a shoulder joint of a humanoid robot. As shown in FIG. 3, the arm 13 can be rotated around the pitch axis and the roll axis at the upper left and right ends of the body frame 21 via the pitch axis joint structure 22 and the roll axis joint structure 23. Attached to. Each of the joint structure 22 of the pitch axis and the joint structure 23 of the roll axis is a joint structure having one rotation output shaft and one degree of freedom of rotation. The pitch axis joint structure 22 rotates the arm 13 around the pitch axis (y-axis in the figure), and the roll axis joint structure 23 rotates the arm 13 around the roll axis (x-axis in the figure). By combining the joint structure 22 of the pitch axis and the joint structure 23 of the roll axis, a shoulder joint having a degree of freedom of rotation of 2 is obtained. An elbow joint 29 having one degree of freedom of rotation is provided at the lower end of the arm portion 13. The torso part frame 21 is supported by the pelvis frame 26 through the waist joint 25. The head 14 is placed on the body frame 21 via the neck joint 27.

  As shown in FIG. 4, the pitch shaft joint structure 22 includes a first frame 31 as a first member, a rotation output shaft 32 that is rotatably supported by the first frame 31, and two rotation rotation shafts 32 that rotate the rotation output shaft 32. Linear actuators 24a and 24b (see FIG. 5) are provided. The first frame 31 is coupled to the body part frame 21. A shoulder frame 41 as a second member is coupled to the rotation output shaft 32. When the rotation output shaft 32 is rotated by the two linear motion actuators 24 a and 24 b, the shoulder frame 41 rotates around the rotation output shaft 32 (pitch axis (y axis)) with respect to the first frame 31.

  The shoulder frame 41 is formed by bending a thin plate into a substantially U-shape, and a pair of parallel arm support plates 41a and 41b facing each other and a base plate 41c connecting the pair of arm support plates 41a and 41b. . The arm support plates 41a and 41b and the base plate 41c are orthogonal to each other. The rotation output shaft 32 of the joint structure 22 of the pitch axis is coupled to the back surface of the base plate 41c. The base plate 41c has a through hole 42 that is aligned with the axis of the rotation output shaft 32. A large number of through holes 43 through which fastening members such as bolts are passed as attachment portions are formed around the through holes 42. The base plate 41c and the rotation output shaft 32 are coupled by a fastening member such as a bolt.

  Between the pair of arm support plates 41a and 41b of the shoulder frame 41, a roll shaft joint structure 23 is provided to be rotatable around the roll shaft (x axis). The joint structure 23 of the roll shaft includes an arm part frame 51 as a first member, a rotation output shaft 52 that is rotatably supported relative to the arm part frame 51, and two linear motion actuators 54a that rotate the rotation output shaft 52. , 54b (see FIG. 5). As will be described later, the pitch shaft joint structure 22 and the roll shaft joint structure 23 have the same structure. The rotation output shaft 52 is coupled to the support plate 41 b of the shoulder frame 41. The support plate 41b has a through hole 44 that is aligned with the axis of the rotation output shaft 52. Around the through-hole 44, a large number of through-holes 45 through which fastening members such as bolts are passed as attachment portions. The support plate 41b and the rotation output shaft 52 are coupled by a fastening member such as a bolt.

  When the rotation output shaft 52 is relatively rotated by the two linear actuators 54a and 54b of the roll shaft joint structure 23, the rotation output shaft 52 is non-rotatably coupled to the shoulder frame 41. 51 rotates around the roll axis (x-axis) with respect to the shoulder frame 41. The axis of the rotation output shaft 32 of the pitch shaft joint structure 22 and the axis of the rotation output shaft 52 of the roll shaft joint structure 23 are orthogonal to each other. By operating the joint structure 22 of the pitch axis and the joint structure 23 of the roll axis, the arm part frame 51 rotates about two axes (pitch axis and roll axis) perpendicular to the body part frame 21.

  FIG. 5 is a perspective view of the joint structure of the robot according to the present embodiment. The pitch axis joint structure 22 and the roll axis joint structure 23 have the same structure. Here, the pitch axis joint structure 22 will be described, and the components of the roll axis joint structure 23 corresponding to the components of the pitch axis joint structure 22 are indicated by parenthesized symbols.

  The joint structure of the robot according to the present embodiment includes a first frame 31 as a first member, a rotation output shaft 32 rotatably supported by the first frame 31, and first and second straight shafts that rotate the rotation output shaft 32. The moving actuators 24a and 24b are basic components. When the first and second linear actuators 24 a and 24 b are operated, the rotation output shaft 32 rotates about the axis A <b> 1 with respect to the first frame 31.

  When the joint structure of the robot of this embodiment is used as the joint structure 22 of the pitch axis, the first frame 31 is coupled to the body frame 21 and the rotation output shaft 32 is connected to the shoulder frame 41 as shown in FIG. Combined. When the joint structure of the robot according to the present embodiment is used as the roll shaft joint structure 23, the rotation output shaft 52 is coupled to the shoulder frame 41. The arm part frame 51 as the first frame has both a function as a frame of the joint structure 23 of the roll shaft and a function as a frame of the arm part 13.

  As shown in FIG. 5, the first frame 31 includes a pair of parallel support plates 31 a and 31 b that are opposed to each other and a connecting plate 31 c that connects one end portion (the lower end portion in the drawing) of the supporting plates 31 a and 31 b in the length direction. And the whole is formed in a U-shape. The support plates 31a and 31b are formed in a substantially rectangular shape elongated in the vertical direction in the figure. The upper ends of the support plates 31a and 31b are formed in a semicircular shape. The connection plate 31c is formed in a square shape. Circular through holes 31a1 and 31b1 whose centers coincide with the axis A1 of the rotation output shaft 32 are formed in the upper portions of the support plates 31a and 31b. The upper portions of the pair of support plates 31 a and 31 b are connected by a stud 33.

  Around the through holes 31a1 and 31b1 of the support plates 31a and 31b, bearings 34a and 34b for rotatably supporting the rotation output shaft 32 are attached. A plain bearing or a rolling bearing may be used as the bearings 34a and 34b.

  The rotation output shaft 32 is sandwiched between a pair of support plates 31a and 31b, and is supported by bearings 34a and 34b so as to be rotatable around an axis A1. A coupling portion 36 coupled to the shoulder frame 41 is formed at one end portion of the rotation output shaft 32 in the axial direction. The coupling portion 36 is exposed from the through hole 31b1 of the support plate 31b and protrudes from the support plate 31b. A plurality of screw holes 36a are formed in the end surface of the coupling portion 36 as a mounting portion in the circumferential direction.

  The rotation output shaft 32 has a pair of flanges 32a and 32b spaced apart in the axial direction. The flanges 32a and 32b have a shape based on a ring, and a part of the outer periphery is cut away so as to avoid the interference of the stud 33. A pair of output shaft side connecting shafts 35a and 35b (see FIG. 8) is rotatably spanned between the flanges 32a and 32b. The pair of output shaft side connecting shafts 35a and 35b are disposed at positions separated by 180 ° in the circumferential direction of the flange. The axes of the output shaft side connecting shafts 35a and 35b are parallel to the axis A1 of the rotation output shaft 32.

  The rotation output shaft 32 is a hollow shaft, and a through hole 32c penetrating in the axial direction is formed therein. Further, a slit 32 d that connects the external space of the rotary output shaft 32 and the internal space of the rotary output shaft 32 is formed midway in the axial direction of the rotary output shaft 32. The slit 32d is provided between the flanges 32a and 32b and extends elongated in the circumferential direction.

  As shown in FIG. 4, the wiring 48 extending from the body frame 21 to the shoulder frame 41 is passed through the rotation output shaft 32 of the joint structure 22 of the pitch axis. The wiring 48 passes through the through hole 42 of the shoulder frame 41 and moves toward the arm frame 51. The wiring 48 passes through the hollow space of the rotation output shaft 52 via the slit 52d of the rotation output shaft 52 of the roll shaft joint structure 23, jumps out of the through hole 44 of the support plate 41b, and then rolls the joint structure 23 of the roll shaft. Are connected to the master and slave control devices 61a and 61b.

  As shown in FIG. 5, the first and second linear actuators 24a and 24b are rotatably sandwiched between a pair of support plates 31a and 31b. As shown in the detailed view of FIG. 6, each of the first and second linear actuators 24a and 24b linearly moves in the axial direction with respect to the cylindrical main body portions 62a and 62b and the main body portions 62a and 62b. Shaft portions 63a and 63b. The structures of the first and second linear actuators 24a and 24b are the same. The shaft portions 63a and 63b are disposed on the center lines of the main body portions 62a and 62b. A spiral thread groove is formed on the outer peripheral surfaces of the shaft portions 63a and 63b. The main body portions 62a and 62b accommodate ball screw nuts (not shown) that are screwed into the thread grooves of the shaft portions 63a and 63b. In the main body portions 62a and 62b, ball screw nuts are accommodated in the main body portions 62a and 62b in a state in which only rotation around the axis is permitted. The main body portions 62a and 62b further house servo motors that rotate the ball screw nut. When the servo motor rotates the ball screw nut, the movement of the ball screw nut in the axial direction is restricted, so that the shaft portions 63a and 63b move linearly in the axial direction.

  The main body portions 62a and 62b of the first and second linear actuators 24a and 24b are rotatably supported by the support plates 31a and 31b. The main body portions 62a and 62b are fitted into rectangular frames 65a and 65b. The rectangular frames 65a and 65b are provided with rotating shafts 66a and 66b. The rotary shafts 66a and 66b are fitted into the through holes of the support plates 31a and 31b. The main body portions 62a and 62b of the first and second linear motion actuators 24a and 24b can swing around the rotation shafts 66a and 66b. The axes of the rotation shafts 66 a and 66 b are parallel to the axis of the rotation output shaft 32. The shaft portions 63 a and 63 b of the first and second linear actuators 24 a and 24 b are coupled to output shaft side connecting shafts 35 a and 35 b supported by the rotation output shaft 32.

  As shown in FIG. 6, the first and second linear actuators 24 a and 24 b have a center line C <b> 1 passing through the axis A <b> 1 of the rotation output shaft 32 as a boundary when viewed from the axial direction of the rotation output shaft 32. It is arranged on the left and right substantially parallel to the center line C1. The first and second linear motion actuators 24a and 24b may be parallel to such an extent that the mounting space for the first and second linear motion actuators 24a and 24b can be reduced. Since the first and second linear actuators 24a and 24b of the present embodiment swing around the rotary shafts 66a and 66b, they become completely parallel or tilted. As shown in FIG. 6, when the expansion and contraction amounts of the first and second linear motion actuators 24a and 24b are equal, the first and second linear motion actuators 24a and 24b are separated from the center line C1. It is symmetrical.

  As shown in FIG. 5, a master control device 61a and a slave control device 61b for controlling the servo motors of the first and second linear actuators 24a and 24b are attached to the support plate 31b. Each of the master controller 61a and the slave controller 61b includes a power converter such as a PWM (pulse width modulation) inverter that supplies power to the servo motor, a sensor that detects the speed and position of the output shaft of the servo motor, a computer, etc. A controller that controls the power converter based on a command from the host controller (as will be described later, a command from the master control device 61a in the case of the slave control device 61b) and information from the sensor is provided.

  FIG. 7 is a block diagram of a control system for controlling the first and second linear actuators 24a and 24b. The present embodiment is characterized in that master-slave control is performed by the master and slave control devices 61a, 61b, and the servo motors of the first and second linear actuators 24a, 24b are synchronously controlled. The host controller 71 transmits a command only to the master control device 61a. The master control device 61a receives the command transmitted from the host controller 71 and transmits it to the slave control device 61b. The slave control device 61b receives the command transmitted from the master control device 61a. The master control device 61a and the slave control device 61b execute a command and realize synchronous control between the servos of the first and second linear actuators 24a and 24b.

  The synchronous control between the servos of the first and second linear actuators 24a and 24b is performed not only on the position but also on the torque. The slave controller 61b controls the torque of the second linear actuator 24b so as to generate torque in the direction opposite to that of the servo motor of the first linear actuator 24a. That is, the slave controller 61b generates the thrust in the direction in which the second linear actuator 24b pulls when generating the thrust in the direction in which the first linear actuator 24a pushes, and the first linear actuator When the thrust in the pulling direction of the actuator 24a is generated, the torque of the servo motor of the second linear actuator 24b is controlled so that the thrust in the pressing direction of the second linear actuator 24b is generated.

  As shown in FIG. 8, when the master controller 61a and the slave controller 61b are controlled so that the first linear actuator 24a pulls the shaft portion 63a and the second linear actuator 24b pushes the shaft portion 63b, The rotation output shaft 32 rotates counterclockwise. Conversely, when the first linear actuator 24a pushes out the shaft portion 63a and the second linear actuator 24b is controlled to retract the shaft portion 63b, the rotation output shaft 32 rotates in the clockwise direction. The first and second linear actuators 24a and 24b swing around the rotary shafts 66a and 66b (see FIG. 6) as they expand and contract. Since the first and second linear actuators 24a and 24b are rotatably supported by the rotation output shaft 32 and the first frame 31, the first and second linear actuators 24a and 24b expand and contract and swing. However, an excessive force is not applied to the first and second linear actuators 24a and 24b.

  The positions of the servo motors of the first and second linear actuators 24a and 24b are controlled so as to eliminate rattling of the joint structures 22 and 23 of the robot of this embodiment. The backlash of the ball joints of the first and second linear actuators 24a and 24b, the bearings 34a and 34b, the output shaft side connecting shafts 35a and 35b, and the rotating shaft 66a, This is due to the clearance 66b or the like. If the joint structures 22 and 23 of the robot are rattling, the arm portion 13 shakes and the elongated arm portion 13 cannot be stabilized.

  FIG. 9 shows an example in which a gap exists around the output shaft side connecting shafts 35a and 35b as an example of rattling of the joint structures 22 and 23 of the robot. 9 indicates the position of the output shaft side connecting shafts 35a and 35b separated by a predetermined angle (180 degrees in this embodiment) in the circumferential direction, and the broken line ○ in the drawing indicates the rotation output shaft 32. The positions of the output shaft side connecting shafts 35a and 35b that eliminate rattling are shown. The positions of the solid circle and the broken circle are shifted in the circumferential direction. The first and second control devices (in this embodiment, the master and slave control devices 61a and 61b) that control the servo motor are configured to eliminate the rattling of the rotation output shaft 32, that is, the output shaft side connecting shaft 35a. , 35b are position-controlled so that the servo motors of the first and second linear actuators 24a, 24b are positioned so that the position of the broken line in FIG. When backlash is present in the ball screws of the first and second linear actuators 24a and 24b, the shaft portions 35a and 35b of the first and second linear actuators 24a and 24b are added by an amount corresponding to the backlash. You just have to stretch. By moving the first and second linear actuators 24a and 24b in this manner, the rattling of the joint structures 22 and 23 of the robot can be eliminated.

  The joint structure of the robot according to the embodiment of the present invention has the following effects. In rotating the rotation output shaft 32 relative to the first frame 31, the first and second linear actuators 24a and 24b are expanded and contracted, so that the joint structure using a conventional servo motor of the rotating system is used. Compared to, it is possible to generate several times the force. In other words, the first and second linear actuators 24a and 24b can be reduced in size after obtaining a necessary force. The rotation output shaft 32 and the first and second linear actuators 24a and 24b are provided on the first frame 31, and the first frame 31 and the shoulder frame 41 are not connected by a link or the like. The structure can be miniaturized, and it is possible to construct a human-like thin arm. Furthermore, since the single rotation output shaft 32 is rotated by the two linear actuators 24a and 24b, the first and second linear actuators 24a and 24b are operated by shifting the first and second linear actuators 24a and 24b. It is possible to eliminate rattling of the joint structures 22 and 23 of the robot due to backlash inside the linear motion actuators 24a and 24b, clearance generated in the output shaft side connecting shafts 35a and 35b, bearings 34a and 34b, and the like. Become.

  As shown in FIG. 6, when viewed from the axial direction of the rotary output shaft 32, the first and second linear actuators 24a and 24b are arranged substantially parallel to the center line C1 on the left and right sides of the center line C1. By arranging, the joint structures 22 and 23 of the robot can be reduced in size.

  As shown in FIG. 5, the rotation output shaft 32 and the first and second linear actuators 24 a and 24 b are sandwiched between a pair of support plates 31 a and 31 b of the first frame 31. The joint structures 22 and 23 can be reduced in size and can be easily assembled. By forming the through hole 31b that exposes the coupling portion 36 of the rotation output shaft 32 in the support plate 31b, the rotation output shaft 32 and the shoulder frame 41 can be coupled.

  The rotation output shaft 32 is provided with a pair of flanges 32a and 32b, and the output shaft side connecting shafts 35a and 35b are bridged between the pair of flanges 32a and 32b, thereby rotating with the first and second linear motion actuators 24a and 24b. It becomes easy to connect the output shaft 32 in a rotatable manner, and the rotation output shaft 32 rotates stably.

  As shown in FIG. 4, when the rotation output shaft 32 is a hollow shaft and the wiring 48 is passed through the rotation output shaft 32, the appearance can be improved and the durability of the wiring 48 can be improved. By forming the slit 52d in the rotation output shaft 52 and passing the wiring 48, the wiring does not have to jump out from the end of the rotation output shaft 52 in the axial direction, and the appearance can be further improved. Since the slit 52d of the rotation output shaft 52 is elongated in the circumferential direction, the wiring 48 is not damaged even if the arm frame 51 rotates.

  As shown in FIG. 7, the servomotors of the first and second linear motion actuators 24a and 24b are master-slave controlled, and the second linear motion is generated so that thrust in the direction opposite to that of the first linear motion actuator is generated. By controlling the servo motor of the actuator 24b, it is possible to prevent unnecessary thrust from being generated due to a servo error.

  As shown in FIG. 4, when the first frame is also used as the arm part frame 51, a separate frame for the joint structure 23 is not required, and a thin arm like a human can be constructed.

  By incorporating ball screws with low reverse efficiency into the first and second linear actuators 24a and 24b, it becomes possible to keep the rotary output shafts 32 and 52 stopped even when the servo motor is turned off. .

  The present invention is not limited to being embodied in the above-described embodiment, and can be variously modified without changing the gist of the present invention. For example, a third linear actuator may be provided in addition to the first and second linear actuators, or a third and fourth linear actuator may be provided.

  In this embodiment, master-slave control is performed, but a command may be given independently to the two control devices from the host controller without performing master-slave control.

  A spring that urges the rotation output shaft in the rotational direction may be provided in order to further reduce the backlash caused by the backlash in the first and second linear actuators and the clearance generated in the bearings.

  In the above embodiment, the joint structure of the robot of the present invention is applied to the shoulder joint of the humanoid robot, but it can also be applied to joints other than the shoulder joint. The joint structure of the robot according to the present invention is not limited to a humanoid robot, and can be applied to industrial robots such as a vertical articulated robot and a horizontal articulated robot.

DESCRIPTION OF SYMBOLS 10 ... Humanoid robot, 11 ... Body part, 13 ... Arm part, 22 ... Joint structure of pitch axis, 23 ... Joint structure of roll axis, 24a, 24b ... First and second linear motion actuators, 31 ... First Frame (first member), 31a, 31b ... support plate, 32, 52 ... rotating output shaft, 32a, 32b ... flange, 32c ... through hole, 32d, 52d ... slit, 35 ... coupling portion, 41 ... shoulder frame ( Second member), 48 ... wiring, 51 ... arm portion frame (second member), 61a ... master control device, 61b ... slave control device, 62a, 62b ... main body, 63a, 63b ... shaft, 71 ... high-order controller , A1 ... axis, C1 ... center line

Claims (10)

A robot joint structure that rotates the second member relative to the first member around the axis of the rotation output shaft,
A first member;
A rotation output shaft supported by the first member so as to be rotatable about an axis, and coupled to the second member;
A main body and a shaft that linearly moves with respect to the main body, and either the main body or the shaft can rotate about an axis parallel to the axis of the rotation output shaft of the first member. A first linear actuator and a second linear actuator in which the other of the main body portion and the shaft portion is coupled to the rotation output shaft,
A joint structure of a robot that rotates the rotation output shaft relative to the first member around an axis by extending and contracting the first and second linear actuators.   When viewed from the axial direction of the rotation output shaft, the first and second linear motion actuators are arranged substantially parallel to the center line on the left and right sides of the center line passing through the axis of the rotation output shaft. The joint structure of the robot according to claim 1, wherein: The first member has a pair of opposing support plates,
2. The robot joint structure according to claim 1, wherein the rotation output shaft and the first and second linear motion actuators are sandwiched between the pair of support plates. A coupling portion that can be coupled to the second member is formed at an end portion in the axial direction of the rotation output shaft,
The robot joint structure according to claim 3, wherein a through hole for exposing the coupling portion of the rotation output shaft is formed in one of the pair of support plates. The rotation output shaft has a pair of flanges spaced apart in the axial direction, and a pair of output shaft side connecting shafts rotatably spanned between the pair of flanges,
5. The robot joint structure according to claim 1, wherein the first and second linear motion actuators are coupled to the pair of output shaft side coupling shafts. 6.   The robot joint structure according to any one of claims 1 to 5, wherein the rotation output shaft is a hollow shaft through which wiring can pass.   The robot according to claim 6, wherein the rotation output shaft is formed with a slit that connects an external space of the rotation output shaft and an internal space of the rotation output shaft and allows wiring to pass therethrough. Joint structure. The joint structure of the robot
A master controller and a slave controller for controlling the first and second linear actuators,
The master control device controls the servo motor of the first linear actuator based on a signal from the host controller,
The slave control device controls the servo motor of the second linear actuator based on a signal from the master control device so as to generate thrust in a direction opposite to that of the first linear actuator. The robot joint structure according to claim 1, wherein the joint structure is a robot.   9. A humanoid robot in which the joint structure of the robot according to claim 1 is incorporated in a shoulder joint.   Two joint structures of the robot are provided, two rotation output shafts are combined so that the axes of the rotation output shafts are perpendicular, and the arm portion is rotated about two axes perpendicular to the trunk portion. The humanoid robot according to claim 9.

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