A rope-driven dexterous hand finger structure and rope-driven dexterous hand

Abstract

The application provides a finger structure of a rope-driven dexterous hand, comprising a first knuckle, a second knuckle, a third knuckle and a fourth knuckle; the first knuckle is connected with a first driving mechanism through a first driving rope, the second knuckle is connected with a second driving mechanism through a second driving rope, the third knuckle is connected with a third driving mechanism through a third driving rope, and the fourth knuckle is connected with a fourth driving mechanism through a fourth driving rope; the first driving mechanism, the second driving mechanism, the third driving mechanism and the fourth driving mechanism are respectively used for controlling corresponding knuckles to rotate; the second knuckle and the third knuckle are respectively provided with a first guide and a second guide; one end of a fifth driving rope is fixedly connected with a fifth driving mechanism, and the other end is fixedly connected with the first knuckle through the first guide and the second guide; and the fifth driving mechanism is used for increasing single-finger flexion force of the finger structure.

Description

Technical Field

[0001] This application relates primarily to the field of dexterous hands, and more particularly to a finger structure and a rope-driven dexterous hand. Background Technology

[0002] Existing tethered dexterous hands typically employ a multi-joint structure, with each joint achieving flexion via tendon cords. However, limited installation space within the fingers restricts the radius of the tendon cords at the joints, resulting in a short driving lever arm. Furthermore, the tendon cords must pass through multiple guide wheels or around joint axes, and frictional losses and elastic elongation along the path further reduce the efficiency of force transmission from the actuator to the fingertips. In this structure, even with a certain torque output from the drive motor, the actual flexion force acting on the fingertips is significantly reduced, making it difficult to meet the grasping requirements for heavier objects or stable gripping scenarios. Using high-torque motors or servos to increase flexion force not only requires enlarging the actuator's dimensions, disrupting the compact layout of the fingers and hand, but also significantly increases the cost of the tethered dexterous hand.

[0003] Therefore, we continued to design a finger structure that could increase the finger flexion force and dexterity of the rope-driven dexterous hand. Summary of the Invention

[0004] This application addresses the technical problem of insufficient flexion force in the finger structure of a rope-driven dexterous hand by providing a finger structure for a rope-driven dexterous hand. This finger structure includes a first phalanx, a second phalanx, a third phalanx, and a fourth phalanx. The first and second phalanxes are detachably and rotatably connected, as are the second and third phalanxes, and the third and fourth phalanxes. The first phalanx is connected to a first drive mechanism via a first drive rope, the second phalanx to a second drive mechanism via a second drive rope, the third phalanx to a third drive mechanism via a third drive rope, and the fourth phalanx to a fourth drive mechanism via a fourth drive rope. The first, second, third, and fourth drive mechanisms are used to control the rotation of the corresponding phalanxes. The second and third phalanxes are respectively provided with a first guide and a second guide. One end of a fifth drive rope is fixedly connected to a fifth drive mechanism, and the other end passes through the first and second guides and is fixedly connected to the first phalanx. The fifth drive mechanism is used to increase the single-finger flexion force of the finger structure.

[0005] In one embodiment of this application, the second, third, and fourth phalanges each include a first connecting portion, the first connecting portion including a first ear plate, the first ear plate being provided with a first engaging groove; the first, second, third, and fourth phalanges are each provided with a first bearing; when the first phalanx is connected to the second phalanx, the first bearing of the first phalanx engages with the first engaging groove of the second phalanx; when the second phalanx is connected to the third phalanx, the first bearing of the second phalanx engages with the first engaging groove of the third phalanx; when the third phalanx is connected to the fourth phalanx, the first bearing of the third phalanx engages with the first engaging groove of the fourth phalanx.

[0006] In one embodiment of this application, the first connecting portion further includes a second ear plate and a first groove. The first ear plate and the second ear plate are opposite to each other and spaced apart, and the first groove is disposed between the first ear plate and the second ear plate. The first ear plate is provided with a first engaging groove, and the second ear plate is provided with a second engaging groove. The first phalanx, the second phalanx, the third phalanx, and the fourth phalanx are also respectively provided with a second bearing. The first bearing and the second bearing are opposite to each other and spaced apart. When the first phalanx and the second phalanx are connected, the first bearing of the first phalanx engages with the first engaging groove of the second phalanx, and the second bearing of the first phalanx engages with the second engaging groove of the second phalanx. The second snap-fit ​​groove of the phalanx is provided, and the first phalanx is at least partially disposed in the first groove of the second phalanx; when the second phalanx is connected to the third phalanx, the first bearing of the second phalanx snaps into the first snap-fit ​​groove of the third phalanx, and the second bearing of the second phalanx snaps into the second snap-fit ​​groove of the third phalanx, and the second phalanx is at least partially disposed in the first groove of the third phalanx; when the third phalanx is connected to the fourth phalanx, the first bearing of the third phalanx snaps into the first snap-fit ​​groove of the fourth phalanx, and the second bearing of the third phalanx snaps into the second snap-fit ​​groove of the fourth phalanx, and the third phalanx is at least partially disposed in the first groove of the fourth phalanx.

[0007] In one embodiment of this application, the first phalanx further includes a first guide groove, a first opening of the first guide groove is disposed on a first side of the first phalanx, and a second opening of the first guide groove is disposed on a second side of the first phalanx; a fifth drive rope passes through the first opening into the first guide groove and exits the first guide groove through the second opening; the inner wall of the first guide groove forms a constraint support surface, and when the fifth drive rope is subjected to tension, the fifth drive rope slides along the constraint support surface and bends along a preset trajectory of the first guide groove.

[0008] In one embodiment of this application, the preset trajectory is an arc, a U-shape, or a rounded L-shape.

[0009] In one embodiment of this application, the second phalanx is provided with a second guide groove, and the third phalanx is provided with a third guide groove; the interior of the third phalanx is provided with a second drive rope through hole, and the projection of the second guide groove onto the plane containing the first direction and the second direction at least partially overlaps with the second drive rope through hole; the interior of the fourth phalanx is provided with a third drive rope through hole, and the projection of the third guide groove onto the plane containing the first direction and the second direction at least partially overlaps with the third drive rope through hole.

[0010] In one embodiment of this application, the first, second, third, and fourth phalanges each include a first drive rope fixing hole, a second drive rope fixing hole, a third drive rope fixing hole, and a fourth drive rope fixing hole; the first phalange also includes a fifth drive rope fixing hole; the second drive rope fixing hole is adjacent to the second guide groove, and the third drive rope fixing hole is adjacent to the third guide groove.

[0011] In one embodiment of this application, the first, second, third, and fourth phalanges are respectively provided with a first rotation axis, a second rotation axis, a third rotation axis, and a fourth rotation axis; the first rotation axis and the fourth rotation axis are perpendicular to each other, and the first rotation axis is parallel to the second and third rotation axes; the first drive mechanism, the second drive mechanism, the third drive mechanism, the fourth drive mechanism, and the fifth drive mechanism are arranged sequentially along a third direction.

[0012] This application achieves an overall improvement in the single-finger flexion force of the finger structure by passing the fifth drive rope sequentially through the guides on the second and third phalanges and fixing it to the first phalange. This allows the fifth drive mechanism to apply additional traction force to the first to third phalanges simultaneously when each phalange reaches a preset posture, and this force is superimposed on the force of the original four drive ropes.

[0013] To address the aforementioned technical problems, this application also provides a rope-driven dexterous hand, comprising a palm body, a thumb support, a wrist, a forearm, a thumb, an index finger, a middle finger, a ring finger, and a little finger, wherein the thumb, index finger, middle finger, ring finger, and little finger all have the finger structures described above; the palm body is fixedly connected to the wrist, the thumb support is fixedly connected to the palm body and the wrist, and the wrist is rotatably connected to the forearm; the dexterous hand further includes a first connector, a second connector, a third connector, a fourth connector, and a fifth connector, wherein the second connector, the third connector, the fourth connector, and the fifth connector are all fixedly connected to the palm body, and the first connector is fixedly connected to the thumb support; the thumb is detachably and rotatably connected to the first connector, the index finger is detachably and rotatably connected to the second connector, the middle finger is detachably and rotatably connected to the third connector, the ring finger is detachably and rotatably connected to the fourth connector, and the little finger is detachably and rotatably connected to the fifth connector.

[0014] In one embodiment of this application, the first connector, the second connector, the third connector, the fourth connector, and the fifth connector all include a fourth drive rope through hole; the fourth joints of the thumb, index finger, middle finger, ring finger, and little finger are all provided with a fourth guide groove; the projection of the fourth guide groove onto the plane containing the first direction and the second direction at least partially overlaps with the fourth drive rope through hole.

[0015] In one embodiment of this application, the first driving mechanism, second driving structure, third driving mechanism, fourth driving mechanism, and fifth driving mechanism corresponding to the thumb, index finger, middle finger, ring finger, and little finger are all disposed on the forearm; the first driving mechanism, second driving mechanism, third driving mechanism, fourth driving mechanism, and fifth driving structure of the same finger are arranged sequentially along a third direction; the first driving mechanism, second driving mechanism, third driving mechanism, fourth driving mechanism, and fifth driving structure of different fingers are arranged in a ring; the first driving mechanism, second driving structure, third driving mechanism, fourth driving mechanism, and fifth driving mechanism corresponding to the thumb are disposed on the first side of the forearm.

[0016] The rope-driven dexterous hand of this application has higher flexion force in each finger, which can improve the grip strength of the rope-driven dexterous hand. Attached Figure Description

[0017] The accompanying drawings are included to provide a further understanding of this application; they are incorporated into and constitute a part of this application. The drawings illustrate embodiments of this application and, together with this specification, serve to explain the principles of this application. In the drawings: Figure 1 This is a schematic diagram of a finger structure provided in an embodiment of this application; Figure 2 yes Figure 1 Cross-sectional view of the plane along the first direction and the third direction; Figure 3 yes Figure 1 Another sectional view of the plane along the first direction and the third direction; Figure 4 This is a schematic diagram of the structure of the second phalanx provided in an embodiment of this application; Figure 5 This is a schematic diagram of the structure of the third phalanx provided in an embodiment of this application; Figure 6 This is a schematic diagram of the structure of the fourth phalanx provided in an embodiment of this application; Figure 7 yes Figure 6 A view along the second direction y; Figure 8 yes Figure 7 Sectional view of AA; Figure 9 yes Figure 4 A bottom view; Figure 10 yes Figure 5 A bottom view; Figure 11 yes Figure 6 A bottom view; Figure 12 This is a schematic diagram of the structure of a dexterous hand provided in an embodiment of this application; Figure 13 This is a schematic diagram of the structure of another dexterous hand provided in one embodiment of this application; Figure 14 This is a schematic diagram showing the separation of the palm body, thumb support, and wrist portion according to an embodiment of this application; Figure 15 This is a schematic diagram of the structure of the first connector provided in an embodiment of this application; Figure 16 yes Figure 13 A bottom view.

[0018] Figure label: 100. Finger structure; 110. First knuckle; 111. First guide groove; 112. First side of the first knuckle; 113. Second side of the first knuckle; 114. Inner wall of the first guide groove; 115. First drive rope fixing hole; 116. Fifth drive rope fixing hole; 117. Fifth drive rope; 120. Second knuckle; 121. First guide; 122. Second guide groove; 123. Second drive rope fixing hole; 124. Second drive rope; 125. First drive rope through hole; 130. Third finger joint; 131. Second guide member; 132. Third guide groove; 133. Second drive rope through hole; 140. Fourth finger joint; 142. Fourth drive rope fixing hole; 143. Fourth guide groove; 144. First surface of the fourth finger joint; 150. First connecting part; 151. First ear plate; 152. Second ear plate; 153. First locking groove; 154. Second locking groove; 155. First groove; 01. First pin; 102. Second pin; 200. Dexterous hand; 210. Hand body; 220. Thumb support; 230. Wrist; 240. Forearm; 241. First side of forearm; 251. First connector; 252. Second connector; 253. Third connector; 254. Fourth connector; 255. Fifth connector; 256. Fourth drive rope through hole; 257. Fourth drive rope; 271. Third ear plate; 272. Fourth ear plate; 273, Second groove; 274, Third locking groove; 275, Fourth locking groove; 276, Third guide; 201, Thumb; 202, Index finger; 203, Middle finger; 204, Ring finger; 205, Little finger; 261, First drive mechanism; 262, Second drive mechanism; 263, Third drive mechanism; 264, Fourth drive mechanism; 265, Fifth drive mechanism; x, First direction; y, Second direction; z, Third direction. Detailed Implementation

[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this application. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0020] As indicated in this application, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0021] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0022] In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0023] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0024] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. In addition, although the terminology used in this application is selected from commonly known and used terms, some terms mentioned in this application's specification may have been chosen by the applicant according to his or her judgment, and their detailed meanings are explained in the relevant sections of this description. Moreover, this application should be understood not only through the actual terms used, but also through the meaning implied by each term.

[0025] This application provides a finger structure 100 for a rope-driven dexterous hand, such as... Figures 1-3 and Figure 11As shown, the finger structure 100 includes a first phalanx 110, a second phalanx 120, a third phalanx 130, and a fourth phalanx 140; the first phalanx 110 is detachably and rotatably connected to the second phalanx 120, the second phalanx 120 is detachably and rotatably connected to the third phalanx 130, and the third phalanx 130 is detachably and rotatably connected to the fourth phalanx 140; the first phalanx 110 is connected to the first drive mechanism 261 via a first drive rope, the second phalanx 120 is connected to the second drive mechanism 262 via a second drive rope 124, the third phalanx 130 is connected to the third drive mechanism 263 via a third drive rope, and the fourth phalanx 140... The knuckle 140 is connected to the fourth drive mechanism 264 via the fourth drive rope; the first drive mechanism 261, the second drive mechanism 262, the third drive mechanism 263 and the fourth drive mechanism 264 are respectively used to control the rotation of the corresponding knuckle; the second knuckle 120 and the third knuckle 130 are respectively provided with the first guide 121 and the second guide 131; one end of the fifth drive rope 117 is fixedly connected to the fifth drive mechanism 265, and the other end passes through the second guide 131 and the first guide 121 and is fixedly connected to the first knuckle 110; the fifth drive mechanism 265 is used to increase the single finger flexion force of the finger structure 100.

[0026] The finger structure 100 can serve as a finger component for any finger of the dexterous hand 200, with only slight variations in the proportions of the knuckles of each component. The knuckles are detachably connected, facilitating initial installation and adjustment of the finger structure 100, as well as subsequent maintenance and replacement. In some embodiments, refer to... Figures 1-2As shown, the phalanges are connected end-to-end along the first direction z, and each phalanx has a rotation axis, with each rotation axis corresponding to a degree of freedom. Therefore, the finger structure 100 of this application has four degrees of freedom. The first phalanx 110 is rotatably connected to the second phalanx 120. The first phalanx 110 is connected to the first drive mechanism 261 via a first drive rope, and under the traction of the first drive mechanism 261, the first phalanx 110 can rotate around the first rotation axis. The second phalanx 120 is connected to the second drive mechanism 262 via a second drive rope 124, and under the traction of the second drive mechanism 262, the second phalanx 120 can rotate around the second rotation axis. The third phalanx 130 is connected to the third drive mechanism 263 via a third drive rope, and under the traction of the third drive mechanism 263, the third phalanx 130 can rotate around the third rotation axis. The fourth phalanx 140 is connected to the fourth drive mechanism 264 via a fourth drive rope, and under the traction of the fourth drive mechanism 264, the fourth phalanx 140 can rotate around the fourth rotation axis. In some embodiments, the first drive mechanism 261, the second drive mechanism 262, the third drive mechanism 263, the fourth drive mechanism 264, and the fifth drive mechanism 265 can be analog servos, digital servos, serial bus servos, and motors. It should be noted that the fifth drive mechanism 265 does not affect the normal operation of the other drive mechanisms. The fifth drive rope 117 has a large margin, meaning its length is relatively long. During the movement of each phalanx, it will not affect the extension and flexion of each phalanx. Only when the other four drive mechanisms have adjusted the corresponding phalanx positions will the fifth drive structure pull the fifth drive rope 117. The fifth drive rope 117 transmits tension to the second phalanx 120 and the third phalanx 130 through the first guide member 121 and the second guide member 131. Since the fifth drive rope 117 is directly fixedly connected to the first phalanx 110, it also transmits tension to the first phalanx 110, thereby increasing the flexion force of the finger structure 100. The fifth drive rope 117 contains only one drive rope, and the fifth drive mechanism 265 can only tension or relax the fifth drive rope 117.

[0027] In some embodiments, such as Figures 4-6As shown, the second phalanx 120, the third phalanx 130, and the fourth phalanx 140 all include a first connecting portion 150. The first connecting portion 150 includes a first ear plate 151, and the first ear plate 151 is provided with a first engaging groove 153. The first engaging groove 153 is provided at the head end of the corresponding phalanx. In some embodiments, the first ear plate 151 may be provided on the side of the phalanx or at the center of the phalanx. The first phalanx 110, second phalanx 120, third phalanx 130, and fourth phalanx 140 are each provided with a first pin 101, which is located at the end of the corresponding phalanx. A first bearing (not shown) is mounted on each first pin 101. When the first phalanx 110 is connected to the second phalanx 120, the first bearing of the first phalanx 110 engages with the first engaging groove 153 of the second phalanx 120. When the second phalanx 120 is connected to the third phalanx 130, the first bearing of the second phalanx 120 engages with the first engaging groove 153 of the third phalanx 130. When the third phalanx 130 is connected to the fourth phalanx 140, the first bearing of the third phalanx 130 engages with the first engaging groove 153 of the fourth phalanx 140. The first phalanx 110, second phalanx 120, third phalanx 130, and fourth phalanx 140 are connected end-to-end in sequence. The first bearing of the first finger joint 110 engages with the first retaining groove 153 of the second finger joint 120, allowing the first finger joint 110 to rotate around its pin. The first bearing of the second finger joint 120 engages with the first retaining groove 153 of the third finger joint 130, allowing the second finger joint 120 to rotate around its pin. The first bearing of the third finger joint 130 engages with the first retaining groove 153 of the fourth finger joint 140, allowing the third finger joint 130 to rotate around its pin. This configuration allows the first finger joint 110 to be rotatably connected to the second finger joint 120 via a plug-and-play method, eliminating the need for threaded connections or nut-and-screw connections, reducing installation steps, enabling rapid installation, and improving installation efficiency. During disassembly, only force is required to separate the individual finger joints, achieving quick disassembly.

[0028] In some embodiments, continue to refer to Figures 4-6As shown, the first connecting portion 150 further includes a second ear plate 152 and a first groove 155. The first ear plate 151 and the second ear plate 152 are opposite to each other and spaced apart. The first groove 155 is disposed between the first ear plate 151 and the second ear plate 152. The first ear plate 151 is provided with a first locking groove 153, and the second ear plate 152 is provided with a second locking groove 154. The first phalanx 110, the second phalanx 120, the third phalanx 130, and the fourth phalanx 140 are also respectively provided with a second pin 102. The second pin 102 is provided with a second bearing (not shown in the figure). The second pin 102 is opposite to the first pin 101 and spaced apart. When the first phalanx 110 is connected to the second phalanx 120, the first bearing of the first phalanx 110 is engaged with the first locking groove 153 of the second phalanx 120, and the second bearing of the first phalanx 110 is engaged with the second phalanx 120. The second phalanx 120 is inserted into the second locking groove 154, and the first phalanx 110 is at least partially disposed in the first groove 155 of the second phalanx 120; when the second phalanx 120 is connected to the third phalanx 130, the first bearing of the second phalanx 120 is inserted into the first locking groove 153 of the third phalanx 130, and the second bearing of the second phalanx 120 is inserted into the second locking groove 154 of the third phalanx 130, and the second phalanx 120 is at least partially disposed in the first groove 155 of the third phalanx 130; when the third phalanx 130 is connected to the fourth phalanx 140, the first bearing of the third phalanx 130 is inserted into the first locking groove 153 of the fourth phalanx 140, and the second bearing of the third phalanx 130 is inserted into the second locking groove 154 of the fourth phalanx 140, and the third phalanx 130 is at least partially disposed in the first groove 155 of the fourth phalanx 140. In this structure, the first and second bearings of each finger joint are positioned opposite each other and spaced apart by pins. The first bearing is positioned opposite the first locking groove 153, and the second bearing is positioned opposite the second locking groove 154. When the first finger joint 110 is connected to the second finger joint 120, the first bearing of the first finger joint 110 engages with the first locking groove 153 of the second finger joint 120, and the second bearing of the first finger joint 110 engages with the second locking groove 154 of the second finger joint 120. The first finger joint 110 is at least partially disposed in the first groove 155 of the second finger joint 120. The connection method of other fingers is the same. This arrangement increases the connection stability between the finger joints, and the grooves make the connection between the finger joints tighter.

[0029] In some embodiments, such as Figure 2As shown, the first finger joint 110 also includes a first guide groove 111, with a first opening on a first side 112 and a second opening on a second side 113. A fifth drive rope 117 enters the first guide groove 111 through the first opening and exits through the second opening. The inner wall 114 of the first guide groove forms a constraint support surface. When the fifth drive rope 117 is subjected to tension, it slides along the constraint support surface and bends along a predetermined trajectory of the first guide groove 111. In some embodiments, the first finger joint 110 also includes a fifth drive rope 117 fixing hole 116. After the fifth drive rope 117 exits through the second opening, it is fixed through the fifth drive rope 117 fixing hole 116. The other end of the fifth drive rope 117 is fixedly connected to the fifth drive mechanism 265. Imagine the first knuckle 110 rotating around the first rotation axis. During this rotation, the fifth drive rope 117 will slide relative to the first guide groove 111, following the rotation of the first knuckle 110. When it is necessary to increase the finger flexion force, the fifth drive mechanism 265 will pull the fifth drive rope 117, which will also slide relative to the first guide groove 111. In some embodiments, the preset trajectory is arc-shaped, U-shaped, or L-shaped with rounded corners.

[0030] The advantage of setting the first guide groove 111 is that the inner wall of the first guide groove 111 forms a continuous constraint support surface, providing stable contact support for the fifth drive rope 117. This allows the fifth drive rope 117 to bend along a preset trajectory when pulled by the fifth drive mechanism 265, effectively avoiding the risk of the fifth drive rope 117 becoming loose, swaying, or cutting due to contact with sharp edges on the surface of the first finger joint 110 due to lack of constraint. This improves the smoothness of movement and service life of the fifth drive rope 117. At the same time, when the first finger joint 110 rotates around the first rotation axis, the fifth drive rope 117 can slide relative to the first finger joint 110 in the first guide groove 111 and always adhere to the constraint support surface. This sliding engagement method ensures that the fifth drive rope 117 will not be stuck or excessively worn during the movement of the first finger joint 110, and also ensures that the tension direction of the fifth drive rope 117 is always transmitted along the preset trajectory of the guide groove. This reduces transmission losses caused by sudden changes in rope bending angle or local stress concentration, and improves force transmission efficiency.

[0031] In some embodiments, such as Figures 3-9As shown, the second phalanx 120 is provided with a second guide groove 122, and the third phalanx 130 is provided with a third guide groove 132; the third phalanx 130 has a second drive rope 124 through hole inside, and the projection of the second guide groove 122 onto the plane containing the first direction x and the second direction y at least partially overlaps with the second drive rope 124 through hole; the fourth phalanx 140 has a third drive rope through hole 141 inside, and the projection of the third guide groove 132 onto the plane containing the first direction x and the second direction y at least partially overlaps with the third drive rope through hole 141. In some embodiments, there are multiple drive rope through holes. To facilitate the arrangement of drive ropes between each phalanx and the corresponding drive mechanism, drive rope through holes are provided inside the second phalanx 120, the third phalanx 130, and the fourth phalanx 140. Specifically, the second finger joint 120 is provided with a first drive rope through hole 125, the third finger joint 130 is provided with a second drive rope through hole 133 and a first drive rope through hole 125, and the fourth finger joint 140 is provided with a first drive rope through hole 125, a second drive rope through hole 133, and a third drive rope through hole 141. Taking the connection method of the second drive rope 124 of the second finger joint 120 as an example, the connection method between the drive rope and the drive mechanism is explained. The second finger joint 120 is provided with a second drive rope fixing hole 123, which is threaded. The middle position of the second drive rope 124 is fixedly connected to the second drive rope fixing hole 123 by a screw. The fixedly connected second drive rope 124 can be regarded as two segments. The first segment and the second segment of the second drive rope 124 are respectively arranged to cross the second guide groove 122. The first segment of the second drive rope 124 passes through one second drive rope through hole 133 of the third finger joint 130, and then passes through another second drive rope through hole 133 of the fourth finger joint 140. The second segment of the second drive rope 124 passes through another second drive rope through-hole 133 of the third finger joint 130, and then through another second drive rope through-hole 133 of the fourth finger joint 140. Finally, the ends of the first and second segments of the second drive rope 124 are fixedly connected to the second drive structure, respectively. It can be imagined that when the projection of the second guide groove 122 onto the plane containing the first x-direction and the second y-direction overlaps at least partially with the second drive rope through-hole 133 of the third finger joint 130, the connection path between the second drive rope 124 and the second drive rope through-hole 133 of the third finger joint 130 is the shortest, and the bending angle is small, which can reduce the friction between the second drive rope 124 and the contact surface of the second guide groove 122. The connection methods of the other fingers are similar to those of the second finger joint 120, and will not be described in detail here.

[0032] In some embodiments, such as Figures 3-6As shown, the second guide groove 122 has an arc-shaped cross-section and is coaxially arranged with the first or second bearing of the second finger joint 120. Similarly, the third guide groove 132 is coaxially arranged with the first or second bearing of the third finger joint 130. The fourth finger joint 140 is also provided with a fourth guide groove 143, which is coaxially arranged with the first or second bearing of the fourth finger joint 140. Through the design of the second guide groove 122, since the contact area between the bottom of the second guide groove 122 and the second drive rope 124 is large, the contact stress can be dispersed, avoiding excessive local pressure that could cause wear on the second drive rope 124. At the same time, the arc-shaped transition surface also facilitates the smooth sliding of the second drive rope 124 under the action of the second drive mechanism 262. Correspondingly, the third guide groove 132 and the fourth guide groove 143 have the same function.

[0033] In some embodiments, such as Figures 2-6 The first finger joint 110, second finger joint 120, third finger joint 130, and fourth finger joint 140 respectively include a first drive rope fixing hole 115, a second drive rope fixing hole 123, a third drive rope fixing hole (not shown), and a fourth drive rope fixing hole 142; the first finger joint 110 also includes a fifth drive rope fixing hole 116; the second drive rope fixing hole 123 is adjacent to the second guide groove 122, and the third drive rope fixing hole is adjacent to the third guide groove 132. Placing the drive rope fixing hole on each finger joint adjacent to the corresponding guide groove of the finger joint helps to shorten the length of the drive rope. Furthermore, the opening of the drive rope fixing hole of each finger joint at least partially coincides with the projection of the corresponding second guide groove 122, third guide groove 132, and fourth guide groove 143 onto the plane containing the first direction x and the second direction y. This design also reduces the bending of the drive rope, thereby reducing the friction between the drive rope and the finger joint. Each drive rope fixing hole is equipped with an internal thread, and the drive rope of each finger can be fixed to the corresponding drive rope fixing hole by screws.

[0034] In some embodiments, combined with Figure 1 and Figure 11As shown, the first phalanx 110, second phalanx 120, third phalanx 130, and fourth phalanx 140 are respectively provided with a first rotation axis, a second rotation axis, a third rotation axis, and a fourth rotation axis; the first rotation axis and the fourth rotation axis are perpendicular to each other, and the first rotation axis is parallel to the second rotation axis and the third rotation axis; the first drive mechanism 261, the second drive mechanism 262, the third drive mechanism 263, the fourth drive mechanism, and the fifth drive mechanism 265 are arranged sequentially along a third direction. Specifically, the first rotation axis extends along the second direction y, and the fourth rotation axis extends along the first direction x. In this application, the first direction x, the second direction y, and the third direction are mutually perpendicular, forming a right-handed coordinate system. The movement of the finger structure 100 will be described in detail later in conjunction with the palm structure. The finger structure 100 of this application has five drive mechanisms, and the arrangement of the drive mechanisms is closely related to the wiring of the drive ropes. Specifically, each drive mechanism is arranged sequentially along a third direction, and the arrangement position is the same as the arrangement position of each phalanx. With this configuration, the drive rope of each finger joint is shorter and has a smaller bending angle in its connection with the corresponding drive structure. This is beneficial for reducing friction loss and elastic elongation during transmission, thereby improving the efficiency of force transmission and the response speed.

[0035] In some embodiments, the corresponding drive rope through-holes of the second phalanx 120, third phalanx 130, and fourth phalanx 140 are further provided with sleeves, through which the corresponding drive ropes of each phalanx pass and connect to the corresponding drive mechanism. The sleeves reduce friction of the drive ropes in the drive rope through-holes, making the control of the finger structure 100 more precise; and also reduce wear on the drive ropes, extending their service life.

[0036] This application fixes the fifth drive rope 117 to the first phalanx 110 after passing it through the guides on the second phalanx 120 and the third phalanx 130 in sequence. This allows the fifth drive mechanism 265 to apply additional traction force to the first to third phalanx 130 simultaneously when each phalanx reaches a preset posture. This force is superimposed on the force of the original four drive ropes, effectively improving the overall single-finger flexion force of the finger structure 100.

[0037] This application also provides a rope-driven dexterous hand 200, such as Figures 10-12As shown, the dexterous hand 200 includes a palm body 210, a thumb support 220, a wrist 230, a forearm 240, an index finger 202, a middle finger 203, a ring finger 204, and a little finger 205. The thumb 201, index finger 202, middle finger 203, ring finger 204, and little finger 205 are all finger structures 100 as described above. The palm body 210 is fixedly connected to the wrist 230, the thumb support 220 is fixedly connected to the palm body 210 and the wrist 230, and the wrist 230 is rotatably connected to the forearm 240. The dexterous hand 200 also includes a first connector 251, a second connector 252, and a third connector. 253, fourth connector 254, and fifth connector 255; second connector 252, third connector 253, fourth connector 254, and fifth connector 255 are all fixedly connected to the palm body 210; first connector 251 is fixedly connected to the thumb support 220; thumb 201 is detachably and rotatably connected to first connector 251; index finger 202 is detachably and rotatably connected to second connector 252; middle finger 203 is detachably and rotatably connected to third connector 253; ring finger 204 is detachably and rotatably connected to fourth connector 254; little finger 205 is detachably and rotatably connected to fifth connector 255. In some embodiments, the first connector 251, second connector 252, third connector 253, fourth connector 254, and fifth connector 255 have the same structure.

[0038] In some embodiments, the palm body 210, the second connector 252, the third connector 253, the fourth connector 254, and the fifth connector 255 are provided with a plurality of threaded holes, through which a plurality of screws can pass to fix the second connector 252, the third connector 253, the fourth connector 254, and the fifth connector 255 to the palm body 210 respectively. The first connector 251 is also provided with a plurality of threaded holes, through which a plurality of screws can pass to fix the first connector 251 to the thumb 201 support 220. The thumb support 220 is also fixedly connected to the palm body 210 by screws and threaded holes.

[0039] In some embodiments, such as Figures 13-14 As shown, each connector includes a third ear plate 271, a fourth ear plate 272, and a second groove 273. The third ear plate 271 and the fourth ear plate 272 are spaced apart, and the second groove 273 is located between the third ear plate 271 and the fourth ear plate 272. The third ear plate 271 also includes a third locking groove 274, and the fourth ear plate 272 also includes a fourth locking groove 275. The fourth ear plate 272 is integrally formed, except that it has a protrusion along the second direction y for accommodating the third guide member 276.

[0040] Among them, reference Figure 1 and Figures 10-11As shown, the placement orientation of the first connector 251 differs from that of the other connectors. The first connector 251 is set at a preset angle relative to the third direction z, which can be 45 degrees, 60 degrees, 65 degrees, 70 degrees, 75 degrees, 80 degrees, 85 degrees, or 90 degrees. Correspondingly, the projection of the fourth rotation axis of the fourth phalanx 140 of the thumb 201 onto the plane containing the second direction y and the third direction z is inclined within the plane containing the second direction y and the third direction z. The fourth phalanx 140 of the thumb 201 rotates around the fourth rotation axis, thereby allowing the thumb 201 as a whole to adjust its relative position to the palm body 210. For example, the thumb 201 can be adjusted to be opposite the middle finger 203, opposite the index finger 202, opposite the ring finger 204, or opposite the little finger 205, achieving pinching and grasping actions through the cooperation of other fingers. The second connector 252, the third connector 253, the fourth connector 254, and the fifth connector 255 are all set along the third direction z. The fourth rotation axis of the fourth phalanx 140 of the index finger 202, the middle finger 203, the ring finger 204, and the little finger 205 all extend along the first direction x. When the other phalanxes of the index finger 202, the middle finger 203, the ring finger 204, and the little finger 205 are fixed, the fourth phalanx 140 of the index finger 202, the middle finger 203, the ring finger 204, and the little finger 205 rotates around the fourth rotation axis, thereby realizing the lateral swing of the index finger 202, the middle finger 203, the ring finger 204, and the little finger 205.

[0041] In some embodiments, such as Figure 2 and Figures 13-14 As shown, each connector is also provided with a third guide 276. Specifically, the third guide 276 passes between the two protrusions of the fourth ear plate 272 of each guide, or the third guide 276 is provided on the body of each connector, and multiple third guides 276 can be provided. The third guide 276 is used to guide the fifth drive rope 117 of each finger. The fifth drive rope 117 can pass sequentially around the third guide 276, the second guide 131, the first guide 121, and through the first guide groove 111, and connect to the fifth drive rope 117 fixing hole 116 of the first phalanx 110 of each finger. When the fifth drive mechanism 265 tightens the fifth drive rope 117, the third guide 276 can also act as a fulcrum to pull the third phalanx 130, thereby increasing the flexion force of the finger.

[0042] In some embodiments, such as Figure 1 , Figure 6 and Figures 13-14As shown, the first connector 251, the second connector 252, the third connector 253, the fourth connector 254, and the fifth connector 255 all include a fourth drive rope through hole 256; the fourth phalanx 140 of the thumb 201, index finger 202, middle finger 203, ring finger 204, and little finger 205 are all provided with a fourth guide groove 143; the projection of the fourth guide groove 143 onto the plane containing the first direction x and the second direction y at least partially overlaps with the fourth drive rope through hole 256. The advantage of the projection of the fourth guide groove 143 at least partially overlapping with the fourth drive rope is that the connection path between the fourth drive rope and the fourth drive rope through hole 256 of the connector is the shortest, and the bending angle is small, reducing the friction between the fourth drive rope and the sidewall of the fourth guide groove 143.

[0043] In some embodiments, such as Figures 6-8 as well as Figure 16 As shown, the fourth phalanx 140 is provided with two fourth guide grooves 143, which are respectively located on the first surface 144 and the second surface of the fourth phalanx, with the first and second surfaces of the fourth phalanx facing each other along the first direction x. The two fourth guide grooves 143 are respectively positioned opposite to two fourth drive rope through holes 256, and the projections of the two fourth guide grooves 143 onto the planes containing the first direction x and the second direction y respectively at least partially overlap with the fourth drive rope through holes 256. Each finger's fourth phalanx 140 is also provided with two fourth drive rope fixing holes 142 and two fourth drive ropes 257. The two fourth drive ropes 257 are respectively fixed to the fourth drive rope fixing holes 142, each passing around a fourth guide groove 143, and after crossing, each passing through a fourth drive rope through hole 256, finally being fixedly connected to the fourth drive mechanism 264.

[0044] In some embodiments, the fourth drive rope through-hole 256 is also provided with the sleeve to reduce friction between the fourth drive rope and the fourth drive rope through-hole 256 within the connector. For example... Figure 13 As shown, one of the fourth drive rope through holes 256 is disposed near the third ear plate 271, and the other fourth drive rope through hole 256 is disposed near the fourth ear plate 272. In some embodiments, such as Figures 7-9 and Figure 14As shown, the first drive rope through-hole 125, the second drive rope through-hole 133, and the third drive rope through-hole 141 of each connector are located at the center of the connector. The cross-section of the first drive rope through-hole 125, the second drive rope through-hole 133, and the third drive rope through-hole along the first direction x is quadrilateral. The fourth drive rope through-hole 256 can be located from both sides of the connector toward the center of the connector, and the fourth drive rope through-hole 256 can be arc-shaped. With this arrangement, the fourth drive rope can move from the side of the connector toward its center, making the fourth drive rope closer to the neutral surface of the connector, reducing the influence of the connector deformation on the fourth drive rope, and improving the control accuracy of the fourth drive rope. Furthermore, the outward direction of the fourth drive rope can also be adjusted to facilitate the subsequent wiring of the drive rope of the dexterous hand 200.

[0045] In some embodiments, such as Figures 10-12 As shown, the palm body 210 is fixedly connected to the wrist 230, the thumb 201 support 220 is fixedly connected to the wrist 230, the wrist 230 has two degrees of freedom, and the wrist 230 is rotatably connected to the forearm 240 of the dexterous hand 200.

[0046] In some embodiments, the first drive mechanism 261, second drive structure, third drive mechanism 263, fourth drive mechanism 264, and fifth drive mechanism 265 corresponding to the thumb 201, index finger 202, middle finger 203, ring finger 204, and little finger 205 are all disposed on the forearm 240; the first drive mechanism 261, second drive mechanism 262, third drive mechanism 263, fourth drive mechanism 264, and fifth drive structure of the same finger are arranged sequentially along the third direction z; the first drive mechanism 261, second drive mechanism 262, third drive mechanism 263, fourth drive mechanism 264, and fifth drive structure of different fingers are arranged in a ring. The first drive mechanism 261, second drive structure, third drive mechanism 263, fourth drive mechanism 264, and fifth drive mechanism 265 corresponding to the thumb 201 are disposed on the first side surface 241 of the forearm. It can be imagined that with each drive corresponding to the thumb 201 disposed on the first side surface 241 of the forearm, the drive rope paths of the thumb 201 are shorter and the bending angle is smaller, reducing the transmission loss of the thumb 201.

[0047] The rope-driven dexterous hand 200 of this application has higher flexion force for each finger, which can improve the grip strength of the rope-driven dexterous hand 200.

[0048] The basic concepts have been described above. Obviously, for those skilled in the art, the above disclosure is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application, and therefore remain within the spirit and scope of the exemplary embodiments of this application.

[0049] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic related to at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0050] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that such numbers used to describe embodiments are sometimes modified by the terms "approximately," "approximately," or "generally." Unless otherwise stated, "approximately," "approximately," or "generally" indicates that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in this application are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ a general method of digit preservation. Although the numerical ranges and parameters used to confirm their breadth of range in some embodiments of this application are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

Claims

1. A finger structure for a rope-driven dexterous hand, characterized in that, The finger structure includes a first phalanx, a second phalanx, a third phalanx, and a fourth phalanx; The first phalanx and the second phalanx are detachably and rotatably connected, the second phalanx and the third phalanx are detachably and rotatably connected, and the third phalanx and the fourth phalanx are detachably and rotatably connected. The first finger joint is connected to the first drive mechanism via a first drive rope, the second finger joint is connected to the second drive mechanism via a second drive rope, the third finger joint is connected to the third drive mechanism via a third drive rope, and the fourth finger joint is connected to the fourth drive mechanism via a fourth drive rope. The first drive mechanism, the second drive mechanism, the third drive mechanism, and the fourth drive structure are respectively used to control the rotation of the corresponding knuckles; The second and third phalanges are respectively provided with a first guide and a second guide. One end of the fifth drive rope is fixedly connected to the fifth drive mechanism, and the other end passes through the first and second guides and is fixedly connected to the first phalange. The fifth drive mechanism is used to increase the single-finger flexion force of the finger structure.

2. The finger structure as described in claim 1, characterized in that, The second, third, and fourth phalanges each include a first connecting portion, the first connecting portion including a first ear plate, and the first ear plate being provided with a first snap-fit ​​groove; The first phalanx, the second phalanx, the third phalanx, and the fourth phalanx are each provided with a first bearing; When the first phalanx is connected to the second phalanx, the first bearing of the first phalanx engages with the first locking groove of the second phalanx. When the second phalanx is connected to the third phalanx, the first bearing of the second phalanx engages with the first locking groove of the third phalanx. When the third phalanx is connected to the fourth phalanx, the first bearing of the third phalanx engages with the first engagement groove of the fourth phalanx.

3. The finger structure as described in claim 2, characterized in that, The first connecting portion further includes a second ear plate and a first groove, wherein the first ear plate and the second ear plate are opposite to each other and spaced apart, and the first groove is disposed between the first ear plate and the second ear plate; The first ear plate is provided with a first snap-fit ​​groove, and the second ear plate is provided with a second snap-fit ​​groove; The first phalanx, the second phalanx, the third phalanx, and the fourth phalanx are each provided with a second bearing, with the first bearing and the second bearing being opposite to each other and spaced apart; When the first phalanx is connected to the second phalanx, the first bearing of the first phalanx is engaged in the first engagement groove of the second phalanx, the second bearing of the first phalanx is engaged in the second engagement groove of the second phalanx, and the first phalanx is at least partially disposed in the first groove of the second phalanx. When the second phalanx is connected to the third phalanx, the first bearing of the second phalanx is engaged in the first engagement groove of the third phalanx, and the second bearing of the second phalanx is engaged in the second engagement groove of the third phalanx. The second phalanx is at least partially disposed in the first groove of the third phalanx. When the third phalanx is connected to the fourth phalanx, the first bearing of the third phalanx is engaged in the first engagement groove of the fourth phalanx, the second bearing of the third phalanx is engaged in the second engagement groove of the fourth phalanx, and the third phalanx is at least partially disposed in the first groove of the fourth phalanx.

4. The finger structure as described in claim 1, characterized in that, The first phalanx also includes a first guide groove, a first opening of which is disposed on a first side of the first phalanx, and a second opening of which is disposed on a second side of the first phalanx. The fifth drive rope passes through the first guide groove from the first opening and exits the first guide groove from the second opening; The inner wall of the first guide groove forms a constraint support surface. When the fifth drive rope is subjected to tension, the fifth drive rope slides along the constraint support surface and bends along the preset trajectory of the first guide groove.

5. The finger structure as described in claim 4, characterized in that, The preset trajectory is an arc, a U-shape, or a rounded L-shape.

6. The finger structure as described in claim 4, characterized in that, The second phalanx is provided with a second guide groove, and the third phalanx is provided with a third guide groove; The third finger joint is provided with a second drive rope through hole, and the projection of the second guide groove onto the plane containing the first direction and the second direction at least partially overlaps with the second drive rope through hole. The fourth finger joint has a third drive rope through hole inside, and the projection of the third guide groove on the plane containing the first direction and the second direction at least partially overlaps with the third drive rope through hole.

7. The finger structure as described in claim 6, characterized in that, The first finger joint, the second finger joint, the third finger joint, and the fourth finger joint each include a first drive rope fixing hole, a second drive rope fixing hole, a third drive rope fixing hole, and a fourth drive rope fixing hole; the first finger joint also includes a fifth drive rope fixing hole; The second drive rope fixing hole is adjacent to the second guide groove, and the third drive rope fixing hole is adjacent to the third guide groove.

8. The finger structure as described in claim 3, characterized in that, The first phalanx, the second phalanx, the third phalanx, and the fourth phalanx are respectively provided with a first rotation axis, a second rotation axis, a third rotation axis, and a fourth rotation axis; The first rotation axis is perpendicular to the fourth rotation axis, and the first rotation axis is parallel to the second rotation axis and the third rotation axis. The first drive mechanism, the second drive mechanism, the third drive mechanism, the fourth drive mechanism, and the fifth drive mechanism are arranged sequentially along a third direction.

9. A rope-driven dexterous hand, characterized in that, The dexterous hand includes a palm body, a thumb support, a wrist, a forearm, a thumb, an index finger, a middle finger, a ring finger, and a little finger, wherein the thumb, index finger, middle finger, ring finger, and little finger are all finger structures as described in any one of claims 1-8; The palm body is fixedly connected to the wrist, the thumb support is fixedly connected to the palm body and the wrist, and the wrist is rotatably connected to the forearm. The dexterous hand also includes a first connector, a second connector, a third connector, a fourth connector, and a fifth connector, wherein the second connector, the third connector, the fourth connector, and the fifth connector are all fixedly connected to the palm body, and the first connector is fixedly connected to the thumb support. The thumb is detachably and rotatably connected to the first connector, the index finger is detachably and rotatably connected to the second connector, the middle finger is detachably and rotatably connected to the third connector, the ring finger is detachably and rotatably connected to the fourth connector, and the little finger is detachably and rotatably connected to the fifth connector.

10. The rope-driven dexterous hand as described in claim 9, characterized in that, The first connector, the second connector, the third connector, the fourth connector, and the fifth connector all include a fourth drive rope through hole; The fourth joint of the thumb, index finger, middle finger, ring finger, and little finger is provided with a fourth guide groove; The projection of the fourth guide groove onto the plane containing the first and second directions at least partially overlaps with the fourth drive rope through hole.

11. The rope-driven dexterous hand as described in claim 10, characterized in that, The first drive mechanism, the second drive structure, the third drive mechanism, the fourth drive mechanism, and the fifth drive mechanism corresponding to the thumb, the index finger, the middle finger, the ring finger, and the little finger are all disposed on the forearm; The first driving mechanism, the second driving mechanism, the third driving mechanism, the fourth driving mechanism, and the fifth driving structure of the same finger are arranged sequentially along a third direction; The first driving mechanism, the second driving mechanism, the third driving mechanism, the fourth driving mechanism, and the fifth driving structure for different fingers are arranged in a ring. The first drive mechanism, second drive structure, third drive mechanism, fourth drive mechanism and fifth drive mechanism corresponding to the thumb are disposed on the first side of the forearm.

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