Link mechanism

Abstract

This provides a link mechanism that can generate different forces in the links according to the required force, while suppressing an increase in the number of actuator types with different outputs. [Solution] The finger portion 6 as a link mechanism comprises a plurality of links, including a first link and a second link 12 connected in series via a plurality of joints including a first joint 61 and a second joint 62, and a finger portion drive mechanism 14 for driving the plurality of links. The finger portion drive mechanism 14 comprises a plurality of actuators 55 for driving the plurality of links and a plurality of rods 58 for connecting the actuators 55 to the corresponding links. At least two of the plurality of links are driven by a parallel mechanism connected to the plurality of actuators 55 via a plurality of rods 58.

Description

Technical Field

[0001] The present invention relates to a link mechanism including a plurality of links connected in series via a plurality of joints.

Background Art

[0002] Conventionally, a robot hand device that imitates a human hand has been known for the purpose of causing a robot to perform a wide variety of tasks (for example, Patent Document 1). This robot hand includes a palm portion corresponding to a human palm, a plurality of finger portions connected to the palm portion, and a drive mechanism that drives the finger portions. The finger portion is connected to the palm portion via a joint corresponding to the proximal phalanx of a human hand. The finger portion is provided with two joints corresponding to the middle phalanx and distal phalanx of a human hand, and first to third links arranged in series are connected to the palm portion via these three joints.

[0003] The drive mechanism includes a first drive unit that rotationally drives the first link, a second drive unit that rotationally drives the second link, and a third drive unit that rotationally drives the third link. The first drive unit includes a pulley, a wound cable, a first actuator, and the like. The second drive unit includes a plurality of pulleys, lever links, a trained cable, a second actuator, and the like. The third drive unit includes a plurality of crank arms, auxiliary links, and the like. Certain crank arms and auxiliary links are provided so as to protrude to the ventral side of the first link and the second link.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the conventional technology described above, two actuators are provided for three links, making it impossible to drive the second and third links individually. To drive each link individually (i.e., to increase the degrees of freedom of the fingers), it is conceivable to provide a number of actuators corresponding to the number of links or the degrees of freedom of the fingers. However, the force (torque) required for each link differs depending on the link's position and driving direction. Therefore, it is conceivable to prepare multiple types of actuators with different outputs according to the required force. However, such a configuration would increase manufacturing costs due to the increase in the number of actuator types, and the assembly work would also become more complicated. Furthermore, there is a risk that the device will become larger due to the use of large actuators.

[0006] In view of the above background, the present invention aims to provide a link mechanism that can generate different forces in the link according to the required force, while suppressing an increase in the number of actuator types with different outputs. [Means for solving the problem]

[0007] To solve the above problems, one aspect of the present invention provides a link mechanism comprising a plurality of links connected in series via a plurality of joints, and a drive mechanism for driving the plurality of links, wherein the drive mechanism comprises a plurality of actuators for driving the plurality of links, and a plurality of rods for connecting the actuators to the corresponding links, and at least two of the plurality of joints are driven by a parallel mechanism connected to the plurality of actuators via a plurality of rods. [Effects of the Invention]

[0008] According to this embodiment, it is possible to provide a link mechanism that can generate different forces in the link according to the required force, while suppressing an increase in the number of actuator types. [Brief explanation of the drawing]

[0009] [Figure 1] Perspective view of the main part of the end effector. [Figure 2] Longitudinal cross-sectional view of the base end of the shaft unit [Figure 3] Perspective view of the connection structure of the shaft unit [Figure 4] Rear view of the finger area [Figure 5] Ventral view of the finger [Figure 6] Right side view of the finger [Figure 7] Left side view of the finger [Figure 8] Perspective view showing the finger movement of the fingers [Figure 9] Perspective view showing the flexion and extension movement of the first joint of the finger. [Figure 10] Perspective view showing flexion and extension of the second joint of the finger. [Figure 11] Perspective view showing the flexion and extension movement of the third joint of the finger. [Figure 12] Perspective view showing the overall flexion and extension movement of the fingers. [Modes for carrying out the invention]

[0010] Hereinafter, an embodiment of the end effector 1 to which the present invention is applied will be described with reference to the drawings.

[0011] The end effector 1 is a multi-jointed arm equipped with a hand having multiple degrees of freedom, and constitutes the forearm to fingertip portion of the arm of a so-called humanoid robot. Figure 1 shows a perspective view of the end effector 1 according to an embodiment. However, the configuration shown in Figure 1 is merely an example, and the present invention is not limited to this configuration.

[0012] As shown in Figure 1, the end effector 1 includes a drive source unit 2 corresponding to a forearm portion, and a hand unit 4 connected to the drive source unit 2 via a wrist joint 3. The drive source unit 2 is supported at its proximal end side by an unillustrated upper arm portion via an elbow joint. The hand unit 4 is provided at the distal end portion in the extending direction of the drive source unit 2. Hereinafter, the distal end side in the extending direction of the drive source unit 2 may be referred to as the front side, and the proximal end side as the rear side. The hand unit 4 includes a palm unit 5 connected to the drive source unit 2 via the wrist joint 3, and a plurality of finger units 6 (6A to 6E) movably supported by the palm unit 5. The palm unit 5 corresponds to a human palm, and the finger units 6 correspond to human fingers.

[0013] The hand unit 4 of the present embodiment includes five finger units 6, which are a first finger unit 6A, a second finger unit 6B, a third finger unit 6C, a fourth finger unit 6D, and a fifth finger unit 6E. Hereinafter, when referred to collectively or without distinction, they may be called the finger units 6. The first finger unit 6A corresponds to a thumb, the second finger unit 6B corresponds to an index finger, the third finger unit 6C corresponds to a middle finger, the fourth finger unit 6D corresponds to a ring finger, and the fifth finger unit 6E corresponds to a little finger.

[0014] The wrist joint 3 has a connecting member 7 that couples the drive source unit 2 and the hand unit 4. The connecting member 7 is connected to the drive source unit 2 so as to be rotatable around a first rotation axis 3X extending in a direction different from the extending direction of the drive source unit 2 (hereinafter referred to as the X direction), and is connected to the hand unit 4 so as to be rotatable around a second rotation axis 3Y extending in a direction different from the X direction and the first rotation axis 3X. Thereby, the hand unit 4 is rotatable around the first rotation axis 3X and around the second rotation axis 3Y. In the present embodiment, the first rotation axis 3X is 90 degrees different from the X direction, and the second rotation axis 3Y is 90 degrees different from the first rotation axis 3X. Accordingly, the second rotation axis 3Y may be 90 degrees different from the X direction. Also in the present embodiment, the first rotation axis 3X and the second rotation axis 3Y intersect with each other (that is, are orthogonal to each other).

[0015] The connecting member 7 is connected to the drive source unit 2 via a rotary first speed reduction mechanism 8A provided around the first rotation axis 3X. The palm unit 5 is connected to the drive source unit 2 via a rotary second speed reduction mechanism 8B provided around the second rotation axis 3Y. The first speed reduction mechanism 8A is a drive mechanism that drives the connecting member 7 relative to the drive source unit 2, and the second speed reduction mechanism 8B is a drive mechanism that drives the palm unit 5 relative to the connecting member 7. The two speed reduction mechanisms 8 (8A, 8B) are palm unit drive mechanisms that rotationally drive the palm unit 5 of the hand unit 4 around the first rotation axis 3X and the second rotation axis 3Y relative to the drive source unit 2.

[0016] The connecting member 7 is driven by the first palm unit drive source 9A via the first speed reduction mechanism 8A. The palm unit 5 is driven by the second palm unit drive source 9B via the second speed reduction mechanism 8B. The two palm unit drive sources 9 (9A, 9B) are drive sources that drive the palm unit 5 relative to the drive source unit 2. Each of the palm unit drive sources 9 is mounted on the drive source unit 2, and transmits the palm unit driving force to the rotation shaft portion of the palm unit 5 via a palm unit driving force transmission mechanism (not shown).

[0017] Each finger unit 6 includes a first link 11, a second link 12 and a third link 13 connected in series to the palm unit 5, and a finger unit drive mechanism 14 that drives the first link 11, the second link 12 and the third link 13. Each finger unit drive mechanism 14 is provided on the palm unit 5 and the corresponding finger unit 6. The finger unit drive mechanism 14 that drives the first finger unit 6A is provided on the palm side of the palm unit 5 and the first finger unit 6A. On the other hand, the four finger unit drive mechanisms 14 that drive the second finger unit 6B, the third finger unit 6C, the fourth finger unit 6D and the fifth finger unit 6E are provided on the back side of the palm unit 5 and each finger unit 6.

[0018] Each finger unit 6 is driven by five finger unit drive sources 15 via the finger unit drive mechanism 14. Each finger unit drive source 15 is a drive source that drives the corresponding finger unit 6 relative to the palm unit 5. Each finger unit drive source 15 is mounted on the drive source unit 2, and transmits the finger unit driving force to the corresponding finger unit 6 via a finger unit driving force transmission mechanism 16 to be described later. In the present embodiment, 16 finger unit drive sources 15 are mounted on the drive source unit 2.

[0019] Furthermore, the drive source unit 2 is equipped with a control device 18 that controls the operation of the palm drive source 9 and the finger drive source 15. The control device 18 is positioned to align with the two palm drive sources 9 (9A, 9B) in the X direction.

[0020] The drive source unit 2 has a roughly square cross-sectional shape and includes a drive source casing 20 that defines an internal housing space for housing the palm drive source 9, the finger drive source 15, and the control device 18. The palm drive source 9 is a large electric motor that outputs a relatively large torque, and the finger drive source 15 is a small electric motor that outputs a relatively small torque.

[0021] The palm drive source 9 comprises a motor body 21 that is cylindrical in shape with a relatively large diameter and is short in the axial direction, an output shaft 22 (see Figure 2) that outputs the driving torque of the motor body 21, and a motor driver 23 that drives the motor body 21. The motor body 21 is mounted in a position with the output shaft 22 facing forward (towards the tip of the drive source unit 2) and is mounted in a relatively rear part of the drive source unit 2, that is, in a part that is far behind the wrist joint 3. The motor driver 23 has a rectangular shape that is close to a square when viewed in the direction of the output axis and is integrally provided at the rear end of the motor body 21.

[0022] The finger drive source 15 comprises a motor body 26 that is cylindrical in shape and has a relatively small diameter, an output shaft 27 that outputs driving torque for the motor body 26, and a motor driver 28 that drives the motor body 26. The motor body 26 is mounted in a position with the output shaft 27 facing forward and is mounted on the front part of the palm drive source 9 in the drive source unit 2. The motor driver 28 has a rectangular shape that is close to a square when viewed from the direction of the output shaft 27 and is integrally provided at the rear end of the motor body 26.

[0023] The output shaft 27 of the finger drive source 15 protrudes slightly from the front of the motor body 26, and its tip (output end) is near the front of the motor body 26 of the finger drive source 15. The output shaft 22 of the palm drive source 9 protrudes significantly from the front of the motor body 21 and is positioned to pass through the gap of the finger drive source 15. The tip (output end) of the output shaft 22 of the palm drive source 9 is in the same position as the output end of the finger drive source 15, that is, near the front of the motor body 26 of the finger drive source 15.

[0024] The 16 finger drive sources 15 are arranged in four rows in the direction of the first rotation axis 3X and in four rows in the direction of the second rotation axis 3Y. These finger drive sources 15 are arranged with gaps in both the direction of the first rotation axis 3X and the direction of the second rotation axis 3Y. Here, "with gaps" means that a gap is formed between the motor drivers 28 with the largest cross-sectional dimensions of two adjacent finger drive sources 15.

[0025] The output shaft 22 of each palm drive source 9 is connected to the corresponding reduction mechanism 8 of the connecting member 7 so as to be able to transmit power by a palm drive force transmission mechanism (not shown). In this embodiment, the palm drive force transmission mechanism is composed of a shaft unit 41 (see Figure 2), which will be described later. Similarly, the output shaft 27 of each finger drive source 15 is connected to the corresponding finger drive mechanism 14 of the palm 5 so as to be able to transmit power by a finger drive force transmission mechanism 16 composed of a shaft unit 41 (see Figure 2).

[0026] Figure 2 is a longitudinal cross-sectional view of the base end of the shaft unit 41. As shown in Figure 2, the shaft unit 41 comprises a flexible shaft 42 and an outer tube 43 that covers the flexible shaft 42. The flexible shaft 42 is flexible and configured to be bendable. The flexible shaft 42 is constructed by arranging several strands of steel wire or the like in strips on a single bendable core wire and winding them in a direction that is a predetermined pitch angle with respect to the axis to form the first winding layer, and then repeating the process of arranging strands in strips and winding them in the opposite direction to form the second, third, and subsequent winding layers.

[0027] The outer tube 43 is cylindrical in shape and has an internal bore through which the flexible shaft 42 is inserted. The outer tube 43 is made of a resin material and is configured to bend and deform like the flexible shaft 42. The flexible shaft 42 is slidably inserted into the internal bore of the outer tube 43. It is preferable that grease be injected into the inside of the outer tube 43 as a lubricant. The outer tube 43 protects the flexible shaft 42 from dust and moisture and prevents the flexible shaft 42 from coming into contact with other components.

[0028] The outer tube 43 is made of a porous material. As a result, the grease contained inside seeps out to the outer surface of the outer tube 43. Therefore, when the outer tube 43 comes into contact with and slides against other external components, it can slide with little resistance.

[0029] Connecting members 47 are attached to the base and end of the flexible shaft 42 for the output shafts 22 and 27 of the corresponding palm drive source 9 or finger drive source 15 and the finger drive mechanism 14. The connecting members 47 constitute a first connecting mechanism 48 for the output shafts 22 and 27 of the corresponding palm drive source 9 or finger drive source 15.

[0030] Specifically, the output ends of the output shafts 22 and 27 of the palm drive source 9 and the finger drive source 15 have plate-shaped (minus screwdriver-shaped) engaging projections 49 that extend radially through the center. The connecting member 47 provided at the base end of the flexible shaft 42 has an engaging groove 50 that can receive the engaging projections 49. These constitute the first connecting mechanism 48.

[0031] By sliding the flexible shaft 42 toward the output shafts 22 and 27 at a rotational angle that matches the engagement groove 50 with the engagement projection 49, the engagement projection 49 is inserted into the engagement groove 50. As a result, the flexible shaft 42 and the corresponding output shafts 22 and 27 are connected to each other via the first connecting mechanism 48 so that power can be transmitted between them.

[0032] If the number of palm drive sources 9 and finger drive sources 15 is large, the number of flexible shafts 42 connected to their output shafts 22 and 27 will also increase, and the assembly time of the end effector 1 will be longer. In this embodiment, since the first connecting mechanism 48 is employed, the flexible shafts 42 can be connected to the corresponding output shafts 22 and 27 of the palm drive source 9 or finger drive source 15 by inserting them. Therefore, the assembly time of the end effector 1 is shortened.

[0033] The connecting member 47 of the flexible shaft 42 is rotatably held via a bearing 51 attached to the drive source casing 20 of the drive source unit 2. The outer tube 43 is held slidably and rotatably in the extending direction by a holding member 52 attached to the drive source casing 20.

[0034] Each finger drive mechanism 14 has a plurality of lead screw mechanisms 55 (see Figure 3) to drive the corresponding finger 6 which has four degrees of freedom. As shown in Figure 3, each lead screw mechanism 55 has a screw shaft 56 to which the end of the flexible shaft 42 is connected, a slider 57 having a female thread that screws onto the male thread of the screw shaft 56, and a rod 58 connected to the slider 57. The flexible shaft 42 is connected to one end of the screw shaft 56 via a plug-in type connecting mechanism similar to that in Figure 2. A retaining member 52 (see Figure 2) is attached to the part of the lead screw mechanism 55 on the side to which the flexible shaft 42 is connected, and the outer tube 43 is held by the retaining member 52 so that it can slide and rotate in the extending direction.

[0035] Figure 3 shows the four flexible shafts 42 (first shaft 42A, second shaft 42B, third shaft 42C, and fourth shaft 42D) located at the four corners of the drive source unit 2, while the other flexible shafts 42 are omitted.

[0036] The torque transmitted from the flexible shaft 42 to the screw shaft 56 of the lead screw mechanism 55 is converted into linear motion of the slider 57 and drives the finger drive mechanism 14 via the rod 58. Each finger drive mechanism 14 is provided with multiple lead screw mechanisms 55. Each lead screw mechanism 55 and its corresponding shaft unit 41 constitute the finger drive force transmission mechanism 16 of each finger drive source 15.

[0037] Furthermore, multiple actuators are composed of multiple finger drive sources 15, multiple shaft units 41, and multiple lead screw mechanisms 55. Each lead screw mechanism 55 constitutes the output section of the corresponding actuator. A certain finger 6 is driven with four degrees of freedom by, for example, four actuators via the finger drive mechanism 14.

[0038] Each actuator constitutes a linear actuator that transmits the driving force applied to the finger portion 6 to the rod 58 by the linear motion of the slider 57. In the following description, the four feed screw mechanisms 55 that form the output sections of these four actuators may be referred to as the first actuator 55A, the second actuator 55B, the third actuator 55C, and the fourth actuator 55D.

[0039] The three finger drive mechanisms 14 that drive the second finger portion 6B, the third finger portion 6C, and the fourth finger portion 6D are arranged in a line parallel to each other and along the palm portion 5. On the other hand, the finger drive mechanism 14 for the first finger portion 6A, which corresponds to the thumb, is attached to the palm side of the palm portion 5 parallel to the other finger drive mechanisms 14.

[0040] Next, the structure of the finger portion 6 will be explained with reference to Figures 4 to 7. The second finger portion 6B, the third finger portion 6C, and the fourth finger portion 6D have the same structure. Figures 4 to 7 show one of these finger portions 6, with Figure 4 being a dorsal view, Figure 5 a ventral view, Figure 6 a right lateral view, and Figure 7 a left lateral view. In the following explanation, we will use the anterior-posterior, left-right, and ventral-dorsal directions indicated by arrows in Figures 4 to 7.

[0041] As shown in Figures 4 to 7, the finger portion 6 is equipped with a first link 11, a second link 12, and a third link 13 connected in series to the palm portion 5 as described above. The first link 11 corresponds to the proximal phalanx of a human finger, the second link 12 corresponds to the middle phalanx of the finger, and the third link 13 corresponds to the distal phalanx. The first link 11 is connected to the palm portion 5 via the first joint 61, the second link 12 is connected to the first link 11 via the second joint 62, and the third link 13 is connected to the second link 12 via the third joint 63. The first joint 61 corresponds to the MIP joint of the finger, the second joint 62 corresponds to the PIP joint, and the third joint 63 corresponds to the DIP joint.

[0042] The finger portion 6 comprises multiple links connected in series via multiple joints, and a finger drive mechanism 14 for driving these links, thus constituting a linkage mechanism.

[0043] The finger drive mechanism 14 includes a first drive mechanism 70 that drives the first link 11 around the first joint 61, a second drive mechanism 80 that drives the second link 12 around the second joint 62, and a third drive mechanism 90 that drives the third link 13 around the third joint 63.

[0044] As shown in Figures 4 and 5, the first link 11 is supported on the palm portion 5 so as to be rotatable around the first joint axis 61X, which extends in the dorsal-ventral direction of the first joint 61, and around the second joint axis 61Y, which extends in the left-right direction. The first joint axis 61X and the second joint axis 61Y are connected to each other by a joint axis connecting member 64.

[0045] The second link 12 is connected to the first link 11 so as to be rotatable around the joint axis 62Y that extends in the left-right direction of the second joint 62. The third link 13 is connected to the second link 12 so as to be rotatable around the joint axis 63Y that extends in the left-right direction of the third joint 63. The joint axis 62Y of the second joint 62 and the joint axis 63Y of the third joint 63 are parallel to each other.

[0046] As shown in Figures 5 to 7, the first drive mechanism 70 is equipped with a first actuator 55A and a second actuator 55B as drive sources. As will be described later, the third actuator 55C and the fourth actuator 55D also function as drive sources for the first drive mechanism 70, but this will be explained after the description of the second drive mechanism 80 and the third drive mechanism 90.

[0047] The first actuator 55A (its output end, the slider 57) is connected via the first rod 58A to the dorsal portion (dorsal to the second joint axis 61Y) of the left proximal end of the first link 11. The second actuator 55B (its output end, the slider 57) is connected via the second rod 58B to the dorsal portion (dorsal to the second joint axis 61Y) of the right proximal end of the first link 11.

[0048] The first actuator 55A and the second actuator 55B drive the corresponding first rod 58A and the second rod 58B in the forward and backward directions, thereby driving the first link 11 around the first joint axis 61X and the second joint axis 61Y of the first joint 61. In other words, the first drive mechanism 70 constitutes a two-row parallel mechanism that drives the first link 11 using the driving force of the first actuator 55A and the second actuator 55B.

[0049] As shown in Figures 4 and 7, the second drive mechanism 80 is equipped with a third actuator 55C as a drive source. As will be described later, the fourth actuator 55D also functions as a drive source for the second drive mechanism 80, but this will be explained after the description of the third drive mechanism 90.

[0050] A rocker 81 extending dorsally is attached to the left base end of the first link 11 so as to be rotatable around a left-right axis. The third actuator 55C (its output end, the slider 57) is connected to the free end of the rocker 81 via the third rod 58C. The base end of a connecting rod 82 is connected to the free end of the rocker 81 so as to be rotatable around a left-right axis. The connecting rod 82 extends forward from its base end along the dorsal side of the second link 12 and is connected at its tip to the dorsal side of the second link 12 (dorsal to the joint axis 62Y of the second joint 62).

[0051] The third actuator 55C drives the third rod 58C in the forward and backward direction, causing the second link 12 to rotate around the joint axis 62Y of the second joint 62.

[0052] As shown in Figures 4 and 6, the third drive mechanism 90 includes a fourth actuator 55D as a drive source.

[0053] A first rocker 91A, extending to the back, is attached to the right base end of the first link 11 so as to be rotatable around the left-right axis. A second rocker 91B, extending to the back, is attached to the right free end of the first link 11 so as to be rotatable around the left-right axis. A third rocker 91C, extending to the back, is attached to the longitudinal middle portion of the second link 12 so as to be rotatable around the left-right axis.

[0054] The fourth actuator 55D (its output end, the slider 57) is connected to the free end of the first rocker 91A via the fourth rod 58D. The base end of the first connecting rod 92A is rotatably connected to the free end of the first rocker 91A around a left-right axis. The first connecting rod 92A extends forward from its base end along the back of the second link 12 and is connected at its tip to the free end of the second rocker 91B. The base end of the second connecting rod 92B is rotatably connected to the free end of the second rocker 91B around a left-right axis. The second connecting rod 92B extends forward from its base end along the backs of the second link 12 and the third link 13, straddling the second joint 62, and is connected at its tip to the free end of the third rocker 91C. The base end of the third connecting rod 92C is rotatably connected to the free end of the third rocker 91C around a left-right axis. The third connecting rod 92C extends forward from its base end along the dorsal side of the third link 13 and is connected at its tip to the dorsal side of the third link 13 (dorsal to the joint axis 63Y of the third joint 63).

[0055] The fourth actuator 55D drives the fourth rod 58D in the forward and backward direction, causing the third link 13 to rotate around the joint axis 63Y of the third joint 63.

[0056] When the second link 12 is driven to rotate around the joint axis 62Y of the second joint 62, the fourth actuator 55D must be operated together with the third actuator 55C to prevent the third link 13 from rotating around the joint axis 63Y of the third joint 63. In other words, when driving the second link 12, the driving force of the fourth actuator 55D is used in addition to the driving force of the third actuator 55C. That is, the second link 12 is driven by a two-row parallel mechanism via the second drive mechanism 80 and the third drive mechanism 90.

[0057] When the first link 11 is driven around the first joint 61, the third actuator 55C and the fourth actuator 55D must be actuated together with the first actuator 55A and the second actuator 55B so that the second link 12 and the third link 13 do not rotate around the joint axis 62Y of the second joint 62 and around the joint axis 63Y of the third joint 63. In other words, when the first link 11 is driven, the driving forces of the third actuator 55C and the fourth actuator 55D are used in addition to the driving forces of the first actuator 55A and the second actuator 55B. That is, the first link 11 is driven by a four-row parallel mechanism via the second actuator 80 and the third actuator 90 in addition to the first drive mechanism 70, which is a two-row parallel mechanism.

[0058] As shown in Figure 4, the third rod 58C and the fourth rod 58D move their front ends slightly from side to side when driving the first link 11 around the first joint axis 61X of the first joint 61. Therefore, the rear ends of the third rod 58C and the fourth rod 58D are supported by the corresponding slider 57 via spherical bearings. The front ends of the third rod 58C and the fourth rod 58D are supported by the corresponding rocker 81 or first rocker 91A via spherical bearings. This makes it possible to smoothly operate the first link 11 around two axes. Universal joints may be used instead of spherical bearings.

[0059] Similarly, the first rod 58A and the second rod 58B also move slightly from side to side at their front ends when driving the first link 11 around the first joint axis 61X of the first joint 61. Therefore, as shown in Figure 5, the rear ends of the first rod 58A and the second rod 58B are supported by the corresponding slider 57 via spherical bearings. The front ends of the first rod 58A and the second rod 58B are also supported by the first link 11 via spherical bearings. This makes it possible to smoothly operate the first link 11 around the two axes. A universal joint may be used instead of a spherical bearing.

[0060] Next, the movement of the finger portion 6, configured in this way, will be explained with reference to Figures 8 to 12. The directions indicated by the arrows in Figures 4 to 7 will be used for this explanation. That is, forward is upward in these figures, and backward is downward in these figures.

[0061] First, we will explain the movement (finger swinging motion) that drives the first link 11 around the first joint axis 61X of the first joint 61. Figure 8 is a perspective view showing the finger swinging motion of the finger part 6. In Figure 8, (A) shows the finger part 6 in the neutral position, (B) shows it tilted to the left, and (C) shows it tilted to the right.

[0062] As shown in Figure 8, when the first rod 58A and the third rod 58C are driven backward from the neutral state (A), and the second rod 58B and the fourth rod 58D are driven forward, the finger portion 6 will be tilted to the left in the state of (B). By driving the four rods 58 in opposite directions, the finger portion 6 will return to the neutral state (A). On the other hand, when the first rod 58A and the third rod 58C are driven forward from the neutral state (A), and the second rod 58B and the fourth rod 58D are driven backward, the finger portion 6 will be tilted to the left in the state of (C). By driving the four rods 58 in opposite directions, the finger portion 6 will return to the neutral state (A).

[0063] Thus, the first link 11 of the finger portion 6 is driven by a four-row parallel mechanism consisting of four actuators (feed screw mechanism 55) numbered from the first to the fourth.

[0064] Next, we will explain the movement (flexion and extension) of the finger portion 6 around the second joint axis 61Y of the first joint 61, around the joint axis 62Y of the second joint 62, and around the joint axis 63Y of the third joint 63.

[0065] Figure 9 is a perspective view showing the flexion and extension movements of the first joint 61 of the finger 6. In Figure 9, (A) shows the finger 6 in an extended state, and (B) shows the finger 6 in a flexed state at the first joint 61.

[0066] As shown in Figure 9, when the first rod 58A and the second rod 58B are driven backward from the extended state (A), and the third rod 58C and the fourth rod 58D are driven forward, the finger portion 6 (first link 11) returns to the flexed state (B). At this time, the third rod 58C and the fourth rod 58D are driven with a larger absolute value (in the opposite direction) than the first rod 58A and the second rod 58B. By driving the four rods 58 in opposite directions, the finger portion 6 returns to the neutral state (A).

[0067] Thus, the first link 11 is driven by a two-row parallel mechanism consisting of two actuators, the first actuator 55A and the second actuator 55B.

[0068] Figure 10 is a perspective view showing the flexion and extension movement of the second joint 62 of the finger 6. In Figure 10, (A) shows the finger 6 in an extended state, and (B) shows the finger 6 in a flexed state at the second joint 62.

[0069] As shown in Figure 10, when the third rod 58C and the fourth rod 58D are driven forward from the extended state (A), the finger portion 6 becomes the flexed state (B). At this time, the third rod 58C is driven more than the fourth rod 58D. By driving the third rod 58C and the fourth rod 58D backward, the finger portion 6 returns to the neutral state (A).

[0070] Figure 11 is a perspective view showing the flexion and extension movement of the third joint 63 of the finger 6. In Figure 11, (A) shows the finger 6 in an extended state, and (B) shows the finger 6 in a flexed state at the third joint 63.

[0071] As shown in Figure 11, when the fourth rod 58D is driven forward from the extended state (A), the finger portion 6 becomes the flexed state (B). By driving the fourth rod 58D backward, the finger portion 6 returns to the neutral state (A).

[0072] Figure 12 is a perspective view showing the flexion and extension movements of the first joint 61, second joint 62, and third joint 63 of the finger portion 6. In Figure 12, (A) shows the finger portion 6 in an extended state, and (B) shows the finger portion 6 in a flexed state at the first joint 61, second joint 62, and third joint 63.

[0073] As shown in Figure 12, from the extended state (A), when the first rod 58A and the second rod 58B are driven backward and the third rod 58C and the fourth rod 58D are driven significantly forward, the finger portion 6 returns to the flexed state (B). At this time, the third rod 58C and the fourth rod 58D are driven with a larger absolute value (in the opposite direction) than the first rod 58A and the second rod 58B. The third rod 58C is driven more than the fourth rod 58D. By driving the four rods 58 in opposite directions, the finger portion 6 returns to the neutral state (A).

[0074] This concludes the description of the embodiments, but the present invention is not limited to the above configuration and can be broadly modified and implemented.

[0075] For example, the end effector 1 of this embodiment has four finger parts 6 to which the link mechanism of the present invention is applied, but it may have three or fewer or five or more finger parts 6. The finger parts 6 do not have to be applied to the fingers of the end effector 1, and may be applied to parts other than the end effector 1, fingers and arms (for example, legs), or to mechanical devices other than humanoid robots.

[0076] Furthermore, the specific configuration, arrangement, and quantity of each component and part can be modified as appropriate, as long as it does not depart from the spirit of the present invention. Also, some or all of the components of the above embodiments may be combined with each other. On the other hand, not all of the components shown in the above embodiments are necessarily essential, and can be selected as appropriate.

[0077] In conclusion, the above embodiments can be summarized as follows:

[0078] The linkage mechanism exemplified by the finger portion 6 comprises a plurality of links (11, 12) connected in series via a plurality of joints exemplified by the first joint 61 and the second joint 62, and a drive mechanism exemplified by the finger drive mechanism 14 for driving the plurality of links. The drive mechanism comprises a plurality of rods 58 for connecting a plurality of actuators exemplified by the lead screw mechanism 55 to the corresponding links for driving the plurality of links, and at least two of the plurality of joints are driven by a parallel mechanism connected to the plurality of actuators via the plurality of rods 58.

[0079] According to this embodiment, different forces corresponding to the required force can be generated in multiple links by a parallel mechanism. Furthermore, because forces are generated in multiple links by a parallel mechanism, there is no need to prepare actuators with different outputs, thus suppressing an increase in the number of actuator types.

[0080] In the above embodiment, preferably, the joint includes a first joint 61 which constitutes a multi-degree-of-freedom joint having at least a first joint axis 61X and a second joint axis 61Y, and the link includes a first link 11 supported via the first joint 61, wherein the first link 11 is driven around the first joint axis 61X by the parallel mechanism and driven around the second joint axis 61Y by the parallel mechanism.

[0081] According to this embodiment, the first link 11 can be driven with a large driving force by a parallel mechanism around two axes, the first joint axis 61X and the second joint axis 61Y.

[0082] In the above embodiment, preferably, the first link 11 is connected to the first actuator 55A via the first rod 58A and to the second actuator 55B via the second rod 58B, and when the first rod 58A is driven in a first direction (rearward) and the second rod 58B is driven in a second direction (forward) opposite to the first direction, the first link 11 is driven in one direction (left) around the first joint axis 61X, the first rod 58A is driven in the second direction (forward) and the second rod 58B The first link 11 is driven in the other direction (right) around the first joint axis 61X when the first rod 58A and the second rod 58B are driven in the first direction (rearward) when the first link 11 is driven in one direction (flexion side) around the second joint axis 61Y when the first rod 58A and the second rod 58B are driven in the second direction (forward) when the first link 11 is driven in the other direction (extension side) around the second joint axis 61Y.

[0083] According to this embodiment, the first link 11 can be driven around two axes, the first joint axis 61X and the second joint axis 61Y, by a parallel mechanism using two rods 58, and the configuration of the drive mechanism is simple.

[0084] In the above embodiment, preferably, the first actuator 55A and the second actuator 55B are linear actuators, the first rod 58A is connected to the first actuator 55A via a spherical bearing, and the second rod 58B is connected to the second actuator 55B via a spherical bearing or a universal joint.

[0085] According to this embodiment, a parallel mechanism around two axes can be constructed using two linear actuators and two rods 58, and the configuration of the drive mechanism is simple. Furthermore, by using spherical bearings or universal joints at the connection between the rods 58 and the actuators (feed screw mechanism 55), the movement of the first link 11 around the two axes can be made smoother.

[0086] In the above embodiment, preferably, the first rod 58A and the second rod 58B are connected to the first link 11 via a spherical bearing or a universal joint.

[0087] According to this embodiment, the movement of the first link 11 around the two axes can be made even smoother.

[0088] In the above embodiment, preferably, the link includes a second link 12 connected to the first link 11 via a second joint 62, and a third link 13 connected to the second link 12 via a third joint 63, wherein the second link 12 is connected to a third actuator 55C via a third rod 58C and at least one connecting rod 82, and the third link 13 is connected to a fourth actuator 55D via a fourth rod 58D and at least two connecting rods 92.

[0089] According to this embodiment, the second link 12 can be driven by the third actuator 55C, and the third link 13 can be driven by the fourth actuator 55D.

[0090] In the above embodiment, preferably, when the first rod 58A and the second rod 58B are driven in the first direction (rearward) and the third rod 58C and the fourth rod 58D are driven in the second direction (forward) at the same time, the first link 11 is driven in one direction (bending side) around the second joint axis 61Y, and when the first rod 58A and the second rod 58B are driven in the second direction (forward) and the third rod 58C and the fourth rod 58D are driven in the first direction (rearward) at the same time, the first link 11 is driven around the second joint axis The first link 11 is driven around the first joint axis 61X in one direction (left) or the other direction (right) when the third rod 58C is driven in the first direction (rearward) and the fourth rod 58D is driven in the second direction (forward). The first link 11 is driven around the first joint axis 61X in one direction (left) or the other direction (right).

[0091] In this embodiment, the first actuator 55A, the second actuator 55B, the third actuator 55C, and the fourth actuator 55D constitute a four-row parallel mechanism that drives the first link 11. Therefore, the first link 11 can be driven around two axes with greater force by using two additional actuators to drive the second link 12 and the third link 13.

[0092] In the above embodiment, preferably, when the third rod 58C and the fourth rod 58D are driven in the second direction (forward), the second link 12 is driven in one direction (flexion side) around the joint axis 62Y of the second joint 62, and when the third rod 58C and the fourth rod 58D are driven in the first direction (rearward), the second link 12 is driven in the other direction (extension side) around the joint axis 62Y of the second joint 62.

[0093] In this embodiment, the third actuator 55C and the fourth actuator 55D constitute a parallel mechanism that drives the second link 12. Therefore, the second link 12 can be driven with greater force using the third actuator 55C for driving the third link 13.

[0094] In the above embodiment, preferably, when the fourth rod 58D is driven in the second direction (forward), the third link 13 is driven in one direction (flexion side) around the joint axis 63Y of the third joint 63, and when the fourth rod 58D is driven in the first direction (rearward), the third link 13 is driven in the other direction (extension side) around the joint axis 63Y of the third joint 63.

[0095] According to this embodiment, the third link 13 can be driven in the same manner as the second link 12. [Explanation of symbols]

[0096] 1: End effector 4: Handball 5: Palm 6: Finger part 11: First Link 12: Second Link 13: Third Link 14: Finger drive mechanism 15: Finger drive source 16: Finger drive force transmission mechanism 41: Shaft Unit 42: Flexible shaft 55: Lead screw mechanism 55A: First actuator 55B: Second actuator 55C: Third actuator 55D: Fourth actuator 56: Screw shaft 57: Slider 58: Rod 58A: First rod 58B: Second rod 58C: Third rod 58D: 4th rod 61: First joint 61X: First joint axis 61Y: Second joint axis 62: Second joint 62Y: Joint axis 63: Third joint 63Y: Joint axis 70: First drive mechanism 80: Second drive mechanism 82: Connecting rod 90: Third drive mechanism 92A: First connecting rod 92B: Second connecting rod 92C: Third connecting rod

Claims

1. A linkage mechanism, Multiple links connected in series via multiple joints, It comprises a drive mechanism for driving a plurality of the aforementioned links, The aforementioned drive mechanism, The system comprises multiple rods for connecting multiple actuators for driving multiple links to corresponding links, A linkage mechanism in which at least two of the multiple joints are driven by a parallel mechanism connected to the multiple actuators via multiple rods.

2. The aforementioned joint includes a first joint which constitutes a multi-degree-of-freedom joint having at least a first joint axis and a second joint axis, The link mechanism according to claim 1, wherein the link includes a first link supported via the first joint, and the first link is configured to be driven around the axis of the first joint by the parallel mechanism and driven around the axis of the second joint by the parallel mechanism.

3. The first link is connected to the first actuator via the first rod and to the second actuator via the second rod. When the first rod is driven in a first direction and the second rod is driven in a second direction opposite to the first direction, the first link is driven in one direction around the second joint axis. When the first rod is driven in the second direction, and the second rod is driven in the first direction, the first link is driven in the other direction around the second joint axis. When the first rod and the second rod are driven in the first direction, the first link is driven in one direction around the first joint axis, The link mechanism according to claim 2, wherein the first link is configured to be driven in the other direction around the first joint axis when the first rod and the second rod are driven in the second direction.

4. The first actuator and the second actuator are linear actuators, The link mechanism according to claim 3, wherein the first rod is connected to the first actuator via a spherical bearing, and the second rod is connected to the second actuator via a spherical bearing or a universal joint.

5. The link mechanism according to claim 4, wherein the first rod and the second rod are connected to the first link via a spherical bearing or a universal joint.

6. The link includes a second link connected to the first link via a second joint, and a third link connected to the second link via a third joint. The second link is connected to the third actuator via a third rod and at least one connecting rod. The linkage mechanism according to claim 3, wherein the third link is connected to the fourth actuator via a fourth rod and at least two connecting rods.

7. When the first rod and the second rod are driven in the first direction, and at the same time the third rod and the fourth rod are driven in the second direction, the first link is driven in one direction around the first joint axis. When the first rod and the second rod are driven in the second direction, and at the same time the third rod and the fourth rod are driven in the first direction, the first link is driven in the other direction around the first joint axis. When the third rod is driven in the first direction and the fourth rod is driven in the second direction, the first link is driven around the second joint axis in one or the other direction. The link mechanism according to claim 6, wherein when the third rod is driven in the second direction and the fourth rod is driven in the first direction, the first link is driven around the second joint axis in the other or one of the other directions.

8. When the third rod and the fourth rod are driven in the second direction, the second link is driven in one direction around the joint axis of the second joint, The linkage mechanism according to claim 7, wherein the second link is configured to be driven in the other direction around the joint axis of the second joint when the third rod and the fourth rod are driven in the first direction.

9. When the fourth rod is driven in the second direction, the third link is driven in one direction around the joint axis of the third joint. The linkage mechanism according to claim 8, wherein when the fourth rod is driven in the first direction, the third link is driven in the other direction around the joint axis of the third joint.

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