A cross-joint transmission mechanism and mechanical finger

Abstract

The present invention provides a cross-joint transmission mechanism and a robotic finger, which relate to the technical field of robotic arms. The cross-joint transmission mechanism is used to drive the bending or extension of the fingertip joint. The cross-joint transmission mechanism includes: a base joint frame and a proximal fingertip frame arranged in sequence, wherein the proximal fingertip frame is rotatably connected to the base joint frame; a first universal joint coupling, which is arranged between the base joint frame and the proximal fingertip frame; a first screw pair, wherein the first screw pair includes a first screw and a first nut that are threaded together, wherein the first nut is fixedly connected to the proximal fingertip frame, one end of the first screw is slidably connected to the output end of the first universal joint coupling, and the input end of the first universal joint coupling is drive-connected to the first rotating drive member. According to the present invention, the size of the fingertip joint can be minimized, thereby improving its compatibility with a humanoid robot and avoiding the fingertip joint angle being affected by the pitch or sway of the proximal fingertip.

Description

Technical Field

[0001] The present invention relates to the technical field of manipulators, and in particular to a cross-joint transmission mechanism and a manipulator finger. Background Art

[0002] A robot arm is an automatic operating device that can imitate certain movements and functions of human hands and arms, and can grasp, move objects or operate tools according to a fixed procedure. It is often used to replace human hands to perform grasping, operation and other tasks, and is characterized by precision and flexibility.

[0003] In the existing technology, the spatial arrangement of components such as the motor and transmission parts of the robot arm is unreasonable, resulting in the fingertips being larger in size and not compatible with humanoid robots. In addition, the movement accuracy of the fingertips will be affected by changes in the state of the proximal knuckles (such as pitch changes), making it difficult to ensure the movement accuracy of the fingertips. Summary of the Invention

[0004] The present invention aims to solve the problem in the prior art that the fingertips are large in size and it is difficult to ensure the movement accuracy of the fingertips.

[0005] To solve the above problems, in a first aspect, the present invention provides a cross-joint transmission mechanism for driving the flexion or extension of the fingertips, comprising:

[0006] A base joint frame and a proximal knuckle frame are arranged in sequence, wherein the proximal knuckle frame and the base joint frame are rotatably connected;

[0007] a first universal joint coupling, disposed between the base joint frame and the proximal knuckle frame;

[0008] The first screw pair is arranged in the proximal knuckle frame, the first screw pair includes a first screw and a first nut threaded together, the first nut is fixedly connected to the proximal knuckle frame, one end of the first screw is slidably connected to the output end of the first universal joint coupling, and the other end of the first screw is connected to the fingertip joint through a push head, so that when the first universal joint coupling is driven by the first rotating drive member and drives the first screw to rotate, the first screw performs a spiral motion relative to the first nut and slides axially relative to the output end of the first universal joint coupling, thereby driving the push head to move, so that the fingertip joint bends or extends.

[0009] Optionally, the first universal joint coupling includes a double universal joint, the double universal joint includes a first joint head, a double fork and a second joint head that cooperate with each other and are arranged in sequence, the input end includes the first joint head, the output end includes the second joint head, the first rotating drive member is drivingly connected to the first joint head so that the double universal joint rotates relative to the base joint frame, the second joint head is provided with a non-circular slide at one end close to the first screw, and one end of the screw is a head that matches the non-circular slide.

[0010] Optionally, the other end of the first screw is fixedly connected to the push head, and the push head is movably connected to the fingertip joint.

[0011] Optionally, the push head includes a bearing housing, a bearing cover and a bearing arranged in the bearing housing, the bearing includes a bearing inner ring and a bearing outer ring that cooperate with each other, the bearing inner ring is fixedly connected to the other end of the first screw, the bearing outer ring is fixedly connected to the bearing housing, the bearing cover is fixedly connected to the bearing housing, and the bearing cover is also movably connected to the fingertip joint.

[0012] Optionally, the bearing cover is threadedly engaged with the bearing housing, and the inner end of the bearing cover abuts against the outer ring of the bearing.

[0013] Optionally, it further includes a second mounting portion, the base joint frame includes a frame body and a first mounting portion, the frame body and the first mounting portion are fixedly connected, the second mounting portion is rotatably connected to the first mounting portion, the proximal knuckle frame is rotatably connected to the second mounting portion, the two rotating shafts at the two rotating connections corresponding to the second mounting portion are not parallel, the input end of the first universal joint coupling is drivingly connected to the output shaft of the first rotating drive member, and the output shaft of the first rotating drive member is rotatably arranged relative to the frame body.

[0014] Optionally, at least one set of mutually cooperating second universal joint coupling and second screw pair is provided between the base joint frame and the proximal knuckle frame. For each set of the second universal joint coupling and the second screw pair, the second screw pair includes a second screw and a second nut with threaded cooperation, and the second nut is fixedly connected to the proximal knuckle frame. The second universal joint coupling is driven by the second rotating drive member, and drives the second screw to rotate and feed relative to the proximal knuckle frame. The input end of the second universal joint coupling is drivingly connected to the output shaft of the second rotating drive member, and the output shaft of the second rotating drive member is rotatably arranged relative to the frame body.

[0015] Optionally, the base joint frame rotates around the proximal knuckle frame within an angle of 0-90°.

[0016] Optionally, when two parallel groups of second universal joint couplings and second screw pairs are provided between the base joint frame and the proximal knuckle frame, if the two second screws in the two groups of second universal joint couplings and second screw pairs feed in opposite directions relative to the proximal knuckle frame, the second mounting portion rotates relative to the first mounting portion; if the two second screws in the two groups of second universal joint couplings and second screw pairs feed in the same direction relative to the proximal knuckle frame, the proximal knuckle frame rotates relative to the second mounting portion and the base joint frame; or, when one group of second universal joint couplings and second screw pair is provided and the second screw feeds relative to the proximal knuckle frame, the proximal knuckle frame rotates relative to the second mounting portion and the base joint frame.

[0017] In the present invention, a first universal joint coupling is disposed between the base joint frame and the proximal knuckle frame. Regardless of whether the proximal knuckle frame and the base joint frame are in a pre-rotational or post-rotational connection state (e.g., when the proximal knuckle frame pitches forward and backward or yaws left and right relative to the base joint frame, pitch and yaw being two common degrees of freedom in humanoid robots), the first universal joint coupling is capable of adaptively torsioning and transmitting torque between the first rotational driver and the first lead screw. Furthermore, because one end of the first lead screw is slidably connected to the output end of the first universal joint coupling, the first lead screw rotates with the first universal joint coupling, resulting in a helical motion relative to the first nut. Furthermore, the first lead screw is capable of adapting to the torsion at the connection with the first rotational driver by sliding axially along the output end of the first universal joint coupling, thereby transmitting power to the push head, which in turn drives the flexion or extension of the fingertip. In other words, the motion output of the fingertip can be independent of changes in the proximal knuckle rotation (e.g., pitch and yaw), and the motion angle of the fingertip is not affected by the proximal knuckle frame. The first rotary drive member, the first universal joint coupling and the first lead screw are distributedly arranged, and none of the three need to be arranged in the space of the fingertip joint, so that the size of the fingertip joint can be reduced as much as possible to improve the compatibility with the humanoid robot. On the other hand, the first rotary drive member can be rear-mounted (away from the fingertip joint) as a driver, so that through the transmission of the first universal joint coupling and the first lead screw, it can be realized. The rigid transmission of the fingertip joint is now realized. The fingertip joint may include the middle finger joint and the fingertip, and coupled bending / extension movement can occur between the two. Therefore, the present invention can drive the bending / extension movement of the fingertip joint through the motor-universal joint-lead screw nut mechanism, thereby realizing cross-joint transmission, and the first universal joint coupling can be arranged in the form of a double universal joint, and the decoupling of the two joint movements in the proximal finger joint frame and the distal fingertip joint is realized through the cooperation of the first universal joint coupling and the first lead screw, thereby avoiding the fingertip joint angle being affected by the pitch or sway of the proximal finger joint frame.

[0018] In a second aspect, the present invention further provides a mechanical finger, comprising the above-mentioned cross-joint transmission mechanism, and also comprising a fingertip section, wherein the fingertip section comprises:

[0019] a first connecting rod, one end of which is hingedly connected to a bearing cover in the cross-joint transmission mechanism;

[0020] a second connecting rod, one end of which is hinged to a proximal knuckle frame in the cross-joint transmission mechanism;

[0021] a folding connecting rod, one end of which is hinged to the proximal knuckle frame and the other end of the first connecting rod, respectively, and the rotation axes of the hinge points are parallel to each other;

[0022] A fingertip link, one end of which is hinged to the other end of the folding link and the other end of the second link, and the rotating axes of each hinge point are parallel to each other, and the other end of the fingertip link is a free end.

[0023] The mechanical finger provided by the present invention has the beneficial effects compared with the existing technology, in addition to the beneficial effects of the cross-joint transmission mechanism compared with the existing technology, also including making the planar four-bar linkage composed of the folding link and the second link rotate around the first middle finger joint rotation axis and the second middle finger joint rotation axis respectively, thereby driving the fingertip link to rotate around the fingertip axis in coupling, thereby realizing output of the fingertip joint in a bent or extended state. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A three-dimensional schematic diagram of a cross-joint transmission mechanism according to an embodiment of the present invention is shown;

[0025] Figure 2 FIG2 shows a top view of a cross-joint transmission mechanism according to an embodiment of the present invention;

[0026] Figure 3 It shows a schematic structural diagram of a fingertip in a bent state according to an embodiment of the present invention;

[0027] Figure 4 It shows a schematic structural diagram of the proximal phalanx in a 90° bent state according to an embodiment of the present invention;

[0028] Figure 5 A schematic diagram of the internal structure of the first double universal joint and the first lead screw in an embodiment of the present invention is shown;

[0029] Figure 6 A schematic diagram of the internal structure of a pusher head according to an embodiment of the present invention is shown;

[0030] Figure 7 A schematic diagram of an explosion of a fingertip joint according to an embodiment of the present invention is shown;

[0031] Figure 8 It shows a schematic structural diagram of the proximal phalanx in a 0° bending state according to an embodiment of the present invention;

[0032] Figure 9 A full view of the proximal phalanx with 0° bending when the proximal phalanx is coupled to the fingertip in an embodiment of the present invention is shown;

[0033] Figure 10 It shows a schematic structural diagram of the coupling between the proximal phalanx and the fingertip phalanx in an embodiment of the present invention;

[0034] Figure 11 It shows a schematic structural diagram of the embodiment of the present invention in which the proximal phalanx and the fingertip are in a bent state;

[0035] Figure 12 shows a graph of the universal joint efficiency experience curve in an embodiment of the present invention;

[0036] Figure 13 It shows a schematic structural diagram of the proximal knuckle before side swing in an embodiment of the present invention;

[0037] Figure 14 It shows a schematic structural diagram of the proximal knuckle side swing in an embodiment of the present invention;

[0038] Figure 15 A structural schematic diagram from the perspective of the base joint in an embodiment of the present invention is shown.

[0039] Description of reference numerals:

[0040] 1. First rotating drive member; 2. Base joint frame; 3. First universal joint coupling; 31. First joint head; 32. Double fork; 33. Second joint head; 4. First lead screw; 5. First nut; 6. Near finger joint frame; 7. Bearing housing; 8. Bearing cover; 9. Main shaft; 10. Second mounting part; 11. First middle finger joint shaft; 12. Folding connecting rod; 13. Second connecting rod; 14. First connecting rod; 15. Second middle finger joint shaft; 16. Fingertip connecting rod; 17. Fingertip shaft; 18. Fingertip joint; 19. Second rotating drive member; 20. Second universal joint coupling; 21. Second lead screw; 22. Second nut; 23. Bearing inner ring; 24. Bearing outer ring; 25. First mounting part; 26. Push head; 27. Frame body. DETAILED DESCRIPTION

[0041] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0042] It should be noted that, in the present invention, relational terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "includes," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0043] Throughout this specification, references to the terms "embodiment," "one embodiment," and "an implementation" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or implementation are included in at least one embodiment or implementation of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or implementation. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or implementations.

[0044] Reference Figures 1-4 The embodiment of the present invention provides a cross-joint transmission mechanism for driving the bending or extension of the fingertip joint 18, comprising:

[0045] The base joint frame 2 and the proximal knuckle frame 6 are arranged in sequence, and the proximal knuckle frame 6 is rotatably connected to the base joint frame 2;

[0046] A first universal joint coupling 3 is provided between the base joint frame 2 and the proximal knuckle frame 6;

[0047] The first screw pair is arranged in the proximal knuckle frame 6, and the first screw pair includes a first screw 4 and a first nut 5 with threaded cooperation. The first nut 5 is fixedly connected to the proximal knuckle frame 6, and one end of the first screw 4 is slidingly connected to the output end of the first universal joint coupling 3, and the other end of the first screw 4 is connected to the fingertip joint 18 through a push head 26, so that when the first universal joint coupling 3 is driven by the first rotating drive member 1 and drives the first screw 4 to rotate, the first screw 4 makes a spiral motion relative to the first nut 5 and slides axially relative to the output end of the first universal joint coupling 3, thereby driving the push head 26 to move, so that the fingertip joint 18 bends or stretches.

[0048] When this embodiment is applied in practice, since the first universal joint coupling 3 is arranged between the base joint frame 2 and the proximal knuckle frame 6, no matter whether the proximal knuckle frame 6 and the base joint frame 2 are in a connection state before rotation or a connection state after rotation (such as the proximal knuckle frame 6 pitches in the front and rear directions or swings in the left and right directions relative to the base joint frame 2, pitching and swinging are two common degrees of freedom of humanoid robots), the first universal joint coupling 3 can adapt to the twisting and transmit the torque between the first rotating drive member 1 and the first screw 4, and due to the first screw 4 The first end is slidably connected to the output end of the first universal joint coupling 3, so the first screw 4 rotates with the first universal joint coupling 3, resulting in a spiral motion relative to the first nut 5, and the first screw 4 can adapt to the torsion at the connection with the first rotating drive member 1 and slide axially along the output end of the first universal joint coupling 3, thereby transmitting power to the push head 26, and then driving the bending or extension of the fingertip joint 18 through the push head 26, that is, the motion output of the fingertip joint 18 can be independent of the change of the rotation of the proximal finger joint (such as pitch and yaw), and the motion angle of the fingertip joint 18 will not be affected by the proximal finger joint. The influence of the angle of the joint frame 6 (such as pitch and roll) is achieved, compared with the movement of the fingertips of existing multi-fingered robots, the individual and precise control of the fingertip joint 18 is achieved. In addition, the first rotating drive member 1, the first universal joint coupling 3 and the first screw 4 are distributed, and all three do not need to be arranged in the space of the fingertip joint 18, so that the size of the fingertip joint 18 can be reduced as much as possible to improve the adaptability with the humanoid robot. On the other hand, the first rotating drive member 1 can be rear-mounted (away from the fingertip joint 18) as a driver, so that through the transmission of the first universal joint coupling 3 and the first screw 4, it can To achieve rigid transmission of the fingertip joint 18, the fingertip joint 18 may include a middle finger joint and a fingertip, and coupled bending / extension movement can occur between the two. Therefore, the present invention can drive the bending / extension movement of the fingertip joint 18 through the motor-universal joint-screw nut mechanism, thereby realizing cross-joint transmission, and the first universal joint coupling 3 can be arranged in the form of a double universal joint, and the cooperation of the first universal joint coupling 3 and the first screw 4 can realize the decoupling of the two joint movements of the proximal finger joint frame 6 and the distal fingertip joint 18, thereby avoiding the angle of the fingertip joint 18 being affected by the pitch and roll angles of the proximal finger joint frame 6.

[0049] The present invention can be applied to all scenarios that require long-distance / cross-joint torque / linear push-pull force transmission. The first screw 4 can be a ball screw. The ball screw has a large length dimension and a small width dimension. Since the first screw 4 is arranged on the proximal knuckle frame 6, its slender structure will not increase the width and thickness of the finger, and the slender space in the proximal knuckle frame 6 is fully utilized, thereby achieving the purpose of controlling the finger size. The ball screw mechanism has a strong load-bearing capacity. Under the same volume, the power it can output is much greater than other transmission mechanisms such as gear mechanisms, thereby improving the load-bearing capacity of the finger without increasing the size. The first rotating drive member 1 can be a motor, and the motors can be arranged entirely on the base joint frame 2, thereby simplifying the electrical wiring.

[0050] The extended universal joint journal cooperates with the slideway and the universal joint head to achieve decoupling of the motion of the proximal knuckle frame 6 and the distal two joints, thereby preventing the angle of the fingertip joint 18 from being affected by the pitch and roll angles of the proximal knuckle frame 6.

[0051] like Figure 2 、 Figure 5 As shown, as an optional embodiment of the present invention, the first universal joint coupling 3 includes a double universal joint, which includes a first joint head 31, a double fork 32, and a second joint head 33 that cooperate with each other and are arranged in sequence. The input end includes the first joint head 31, and the output end includes the second joint head 33. The first rotary drive member 1 is drivingly connected to the first joint head 31 to rotate the double universal joint relative to the base joint frame 2. The end of the second joint head 33 near the first screw 4 is provided with a non-circular slideway, and the end of the first screw 4 is provided with a head that matches the non-circular slideway. The proximal knuckle frame 6 is hinged to the base joint frame 2 via the main shaft 9.

[0052] The non-circular slides include square slides, elliptical slides, polygonal slides, etc. Correspondingly, the head portion matches the shape thereof to ensure that relative sliding can occur between the two, but relative rotation cannot occur.

[0053] In practical application, the double universal joint of this embodiment is composed of two universal joints, namely, a first joint head 31, a double fork 32, and a second joint head 33. They are perpendicular to each other, thereby achieving greater angular adaptability and stable power transmission over a wider angular range. The torque of the first rotating drive member 1 is transmitted to the first joint head 31 and then transmitted out through the double fork 32 and the second joint head 33. The double universal joint rotates relative to the base joint frame 2 due to the drive of the first rotating drive member 1, and due to the fixation of the first nut 5, the first screw 4 performs a spiral motion (a composite motion of rotation and linear sliding) relative to the first nut 5 or the proximal knuckle frame 6. , and the cooperation between the non-circular slide and the head in one end of the first screw 4 enables the first screw 4 to rotate with the rotation of the double universal joint, and when the proximal knuckle frame 6 rotates relative to the base joint frame 2, as the second joint head 33 in the double universal joint twists, the relative distance between the first screw 4 and the proximal knuckle frame 6 changes (it becomes longer when the finger is extended, and shorter vice versa). Due to the cooperation between the non-circular slide and the head, at this time, one end of the first screw 4 will adaptively slide in the non-circular slide, and the first joint head 31 can still drive the first screw 4 to rotate (no relative rotation occurs between the two), so the motion control of the fingertip 18 will not be affected.

[0054] like Figure 3 As shown, as an optional embodiment of the present invention, the other end of the first screw 4 is fixedly connected to the push head 26, and the push head 26 is movably connected to the fingertip joint 18.

[0055] When this embodiment is applied in practice, the first screw 4 is fixedly connected to the push head 26 on one side close to the push head 26, that is, the other side. Since the first screw 4 can undergo axial expansion and contraction, the push head 26 also undergoes axial expansion and contraction, and is movably connected to the fingertip joint 18 through the push head 26. The fingertip joint 18 is generally a multi-link structure. Therefore, the fingertip joint 18 can eventually achieve bending or stretching movements similar to those of a human hand.

[0056] like Figure 6 As shown, as an optional embodiment of the present invention, the push head 26 includes a bearing box 7, a bearing cover 8 and a bearing arranged in the bearing box 7, the bearing includes a bearing inner ring 23 and a bearing outer ring 24 that cooperate with each other, the bearing inner ring 23 is fixedly connected to the other end of the first screw 4, the bearing outer ring 24 is fixedly connected to the bearing box 7, the bearing cover 8 is fixedly connected to the bearing box 7, and the bearing cover 8 is also movably connected to the fingertip joint 18.

[0057] When this embodiment is applied in practice, the inner ring 23 of the bearing is fixed to the first screw 4, and the outer ring 24 of the bearing is fixed to the bearing box 7. When the first screw 4 rotates, the inner ring 23 of the bearing rotates with the first screw 4, and the outer ring 24 of the bearing does not move. Therefore, the bearing box 7 has no rotational motion, only linear motion along the axial direction of the first screw 4, that is, rotation is changed into linear motion; the bearing box 7 is close to the side of the fingertip joint 18, and the inside of the bearing box 7 is tapped with a thread that cooperates with the thread on the bearing cover 8, and the bearing cover 8 presses against the outer ring 24 of the bearing. Therefore, the bearing cover 8 also has no rotational motion, only linear motion along the axial direction of the first screw 4, and a double-ear structure is provided on the outside of the bearing cover 8 for connecting to the fingertip joint 18 to push or pull the fingertip joint 18 to complete the extension or shortening of the fingertip joint 18.

[0058] like Figure 6 As shown, as an optional embodiment of the present invention, the bearing cover 8 is threadedly matched with the bearing housing 7, and the inner end of the bearing cover 8 abuts against the bearing outer ring 24.

[0059] When this embodiment is used in practice, the bearing cover 8 is installed on one side of the bearing housing 7 through threads, so that the inside of the push head 26 is detachable and can be inspected, and the inner end of the bearing cover 8 is in contact with the bearing outer ring 24. An elastic gasket can be set between the inner end of the bearing cover 8 and the bearing outer ring 24 to ensure that the length of the push head 26 can be adjusted to meet the telescopic requirements of the fingertip joint 18.

[0060] like Figure 15 As shown, as an optional embodiment of the present invention, it further includes a second mounting portion 10, the base joint frame 2 includes a frame body 27 and a first mounting portion 25, the frame body 27 and the first mounting portion 25 are fixedly connected, the second mounting portion 10 is rotatably connected to the first mounting portion 25, the proximal knuckle frame 6 is rotatably connected to the second mounting portion 10 (through the main rotating shaft 9), and the two rotating shafts at the two rotating connections corresponding to the second mounting portion 10 (one of which is the main rotating shaft 9, and the other is the rotating shaft at the rotating connection between the second mounting portion 10 and the first mounting portion 25, not named in the figure) are not parallel, and in Figure 15 In the embodiment, the two rotation axes are preferably perpendicular to each other.

[0061] The input end of the first universal joint 3 is drivingly connected to the output shaft of the first rotation driving member 1 , and the output shaft of the first rotation driving member 1 is rotatably arranged relative to the frame body 27 .

[0062] The purpose of arranging the position where the input end of the first universal joint coupling 3 is driven and connected to the first rotating drive member 1 on the frame body 27 is that the first rotating drive member 1 can be directly installed on the frame body 27, or an external input is required. It is only necessary to ensure that the position where the input end is driven and connected to the first rotating drive member 1 is arranged on the frame body 27. A reducer can also be provided between the rotating drive member and the universal joint coupling to ensure the driving connection between the input end of the first universal joint coupling 3 and the first rotating drive member 1, and the driving connection between the second rotating drive member 19 and the second universal joint coupling 20 can also be arranged in the same way.

[0063] When this embodiment is applied in practice, the first mounting portion 25 is arranged at the bottom of the frame body 27, and the second mounting portion 10 can be a U-shaped fork structure, and is set perpendicular to the first mounting portion 25, and the proximal knuckle frame 6 is rotatably mounted on the top of the second mounting portion 10, so as to adapt to the proximal knuckle frame 6 and the second mounting portion 10 rotating together relative to the first mounting portion 25, that is, the proximal knuckle frame 6 and the second mounting portion 10 swing sideways relative to the base joint frame 2, or the proximal knuckle frame 6 rotates relative to the second mounting portion 10, that is, the proximal knuckle frame 6 pitches relative to the base joint frame 2.

[0064] As an optional embodiment of the present invention, the first nut 5 is embedded in the proximal knuckle frame 6 , and the middle section of the first screw 4 is fitted with the first nut 5 .

[0065] Specifically, when the first nut 5 is fixed, it is fixed close to the knuckle frame 6 , and the middle section of the first screw 4 cooperates with the first nut 5 , so that the middle section of the first screw 4 can spirally move relative to the first nut 5 .

[0066] like Figure 15 As shown, as an optional embodiment of the present invention, at least one set of mutually cooperating second universal joint couplings 20 and second screw pairs is provided between the base joint frame 2 and the proximal knuckle frame 6. For each set of the second universal joint couplings 20 and the second screw pairs, the second screw pairs include a second screw 21 and a second nut 22 that are threadedly matched. The second nut 22 is fixedly connected to the proximal knuckle frame 6. The second universal joint coupling 20 is driven by a second rotating drive member 19, and drives the second screw 21 to rotate and feed relative to the proximal knuckle frame 6. The input end of the second universal joint coupling 20 is drivingly connected to the output shaft of the second rotating drive member 19, and the output shaft of the second rotating drive member 19 is rotatably arranged relative to the frame body 27. The structure of the second universal joint coupling 20 is the same as that of the first universal joint coupling 3 and will not be described here.

[0067] When there are multiple groups (at least two groups) of the second universal joint coupling 20 and the second lead screw 21, in the multiple groups of the second universal joint coupling 20 and the second lead screw 21, when the feed direction of the second lead screw 21 is the same, the proximal knuckle frame 6 rotates relative to the second mounting portion 10, that is, the proximal knuckle frame 6 pitches relative to the base joint frame 2; when there are one or more groups (at least two groups) of the second universal joint coupling 20 and the second lead screw 21, when the feed directions of the second lead screw 21 are opposite, that is, the forces on both sides are ultimately inconsistent, and ultimately the proximal knuckle frame 6 and the second mounting portion 10 rotate together relative to the first mounting portion 25 and the frame body 27, that is, the proximal knuckle frame 6 swings sideways relative to the base joint frame 2.

[0068] For each set of the second universal joint coupling 20 and the second lead screw 21, the first rotation driving member 1 and the second rotation driving member 19 can both be motors. When the output shaft of the second rotation driving member 19 rotates, it drives the second universal joint coupling 20 (which can be a double universal joint) to rotate. The rotation of the second universal joint coupling 20 drives the second lead screw 21 to rotate. Since the second nut 22 is fixed to the proximal knuckle frame 6, the rotation of the second lead screw 21 will cause the second lead screw 21 to perform linear motion relative to the second nut 22 and the proximal knuckle frame 6 along the axial direction of the second lead screw 21.

[0069] When the second lead screw 21 is axially shortened in the second nut 22 , the proximal knuckle frame 6 rotates counterclockwise around the main rotation axis 9 relative to the base joint frame 2 , corresponding to the bending of the finger (the phalanx 18 ).

[0070] When the second lead screw 21 extends axially in the second nut 22 , the proximal knuckle frame 6 rotates clockwise around the main rotation axis 9 relative to the base joint frame 2 , corresponding to the extension of the finger (the phalanx 18 ).

[0071] The above can ensure that the movement of the fingertip joint 18 will hardly be affected when the proximal finger joint frame 6 swings or pitches relative to the base joint frame 2.

[0072] like Figure 13 、 Figure 14 and Figure 15As shown, as an optional embodiment of the present invention, the second universal joint coupling 20 and the second screw 21 are provided in one group or two parallel groups. When two parallel groups of the second universal joint couplings 20 and the second screw pairs are provided between the base joint frame 2 and the proximal knuckle frame 6, if the two second screws 21 in the two groups of the second universal joint couplings 20 and the second screw pairs generate feed directions relative to the proximal knuckle frame 6 in opposite directions, the second mounting portion 10 rotates relative to the first mounting portion 25. If the two second screws 21 in the two groups of the second universal joint couplings 20 and the second screw pairs generate feed directions relative to the proximal knuckle frame 6 in the same direction, the proximal knuckle frame 6 rotates relative to the second mounting portion 10 and the base joint frame 2, or, the second universal joint coupling 20 and the second screw pair are provided in one group and the second screw 21 feeds relative to the proximal knuckle frame 6, the proximal knuckle frame 6 rotates relative to the second mounting portion 10 and the base joint frame 2.

[0073] When two parallel groups of the second universal joint coupling 20 and the second lead screw 21 are provided, if the proximal knuckle frame 6 is to be lateralized relative to the base joint frame 2, it is only necessary to ensure that the two second lead screws 21 in the two groups of the second universal joint coupling 20 and the second lead screw 21 have opposite feeding directions, that is, one moves forward relative to the proximal knuckle frame 6 and the other moves backward relative to the proximal knuckle frame 6, thereby completing the rotation of the second mounting portion 10 relative to the first mounting portion 25, so that the proximal knuckle frame 6 and the second mounting portion 10 rotate together relative to the first mounting portion 25, that is, the proximal knuckle frame 6 swings lateralized relative to the base joint frame 2.

[0074] In addition, the settings of the two groups of the second universal joint couplings 20 and the second screw 21 are exactly the same, that is, the rotation directions of the second screws 21 are consistent, for example, both are left-handed or right-handed. At this time, it is only necessary to control the two second screws 21 to rotate in opposite directions, and at this time, it is sufficient to ensure that the corresponding two second rotating drive members 19 rotate in opposite directions; of course, if the corresponding two second rotating drive members 19 rotate in the same direction, in order to achieve the opposite feeding direction of the second screw 21, it is only necessary to ensure that the rotation directions of the two second screws 21 are opposite.

[0075] When the second universal joint coupling 20 and the second lead screw 21 are provided with two parallel groups, if the proximal knuckle frame 6 is to be pitched relative to the base joint frame 2, it is only necessary to ensure that the second lead screws 21 in the two groups of the second universal joint couplings 20 and the second lead screws 21 have the same feeding direction, that is, both move forward or backward relative to the proximal knuckle frame 6, so that the proximal knuckle frame 6 can be rotated relative to the second mounting portion 10, that is, the proximal knuckle frame 6 pitches relative to the base joint frame 2. Similarly, when the second universal joint coupling 20 and the second lead screw 21 are provided with one group, the proximal knuckle frame 6 can also be pitched relative to the base joint frame 2 through one group.

[0076] From the above, it can be seen that the present invention can still achieve motion decoupling in the pitch or roll direction, that is, when the two groups of the second universal joint couplings 20 and the second lead screw 21 are arranged in parallel and the feeding directions of the second lead screw 21 are opposite, the roll has almost no effect on the decoupling produced by the cooperation between the journal slide of the first universal joint coupling 3 and the first lead screw 4, or, when the two groups of the second universal joint couplings 20 and the second lead screw 21 are arranged in parallel and the feeding directions of the second lead screw 21 are the same, the pitch has almost no effect on the decoupling produced by the cooperation between the journal slide of the first universal joint coupling 3 and the first lead screw 4, or, when the arrangement of one group of the second universal joint couplings 20 and the second lead screw 21, the pitch has almost no effect on the decoupling produced by the cooperation between the journal slide of the first universal joint coupling 3 and the first lead screw 4, and therefore can adapt to the precise output of the fingertip joint 18 movement under wider conditions.

[0077] In the present invention, the first nut 5 is fixed to the proximal knuckle frame 6, and the first screw 4 performs spiral motion relative to the first nut 5. The rotation of the first screw 4 is offset by the bearing, and the linear push-pull force is retained to drive the pitching motion of the two distal joints. In addition, the present invention can also rotatably install the screw: a rotating pair is established with the proximal knuckle using the bearing, and a moving pair is established with the proximal knuckle by the slider of the screw nut, and the push-pull force is output through the translation of the nut to drive the pitching motion of the two distal joints.

[0078] The universal joint coupling can be replaced with any other mechanism that can simultaneously transmit torque and withstand a certain axial force, such as a ball cage universal joint or an elastic rope. Any mechanism that can transmit torque, such as a flexible rope, can also be replaced. Movement in the other direction can be achieved by using elastic elements such as springs. By changing the journal length of the universal joint coupling and the length of the lead screw and internal matching slideway, the base joint frame 2 and the proximal knuckle frame 6 can achieve motion decoupling within different ranges of motion.

[0079] like Figure 1 、 Figure 7 、 Figure 8 、 Figure 9 、 Figure 10 and Figure 11As shown, the present invention further provides a mechanical finger, comprising the cross-joint transmission mechanism described in the above embodiment, and further comprising a fingertip section 18, wherein the fingertip section 18 comprises:

[0080] a first connecting rod 14, one end of which is hinged to the bearing cover 8 in the cross-joint transmission mechanism;

[0081] A second connecting rod 13, one end of which is hinged to the proximal knuckle frame 6 in the cross-joint transmission mechanism;

[0082] A folding connecting rod 12, one end of which is hinged to the proximal knuckle frame 6 and the other end of the first connecting rod 14, and the rotation axes of the hinge points are parallel to each other;

[0083] The fingertip link 16 has one end hinged to the other end of the folding link 12 and the other end of the second link 13, and the rotating axes of each hinge point are parallel to each other. The other end of the fingertip link 16 is a free end.

[0084] The fingertip link 16 has its middle section hingedly mounted on the other end of the folding link 12 (via the fingertip shaft 17 ), one end of the fingertip link 16 is a free end, and the other end of the fingertip link 16 is hingedly connected to the other end of the second link 13 .

[0085] The folding link 12 may be in a “V” shape, and the position where it is hinged to the proximal knuckle frame 6 is different from the position where the second link 13 is hinged to the proximal knuckle frame 6 .

[0086] The fingertip link 16 may also be in a "V" shape, with its free end outputting work externally, and its position different from the two ends being hinged to the other end of the folding link 12.

[0087] Specifically, the push head 26 is driven to drive the first connecting rod 14 connected to the push head 26. Since one end of the folding connecting rod 12 is connected to the first connecting rod 14, and the second connecting rod 13 is hinged to the proximal knuckle frame 6, the push head 26 (the bearing cover 8) makes a linear motion, which will cause the planar four-bar linkage composed of the folding connecting rod 12 and the second connecting rod 13 to rotate around the first middle knuckle rotating shaft 11 and the second middle knuckle rotating shaft 15 respectively, thereby driving the fingertip connecting rod 16 to rotate in coupling around the fingertip 18 axis (the movement of one mechanism or component causing the movement of another mechanism or component is called coupled motion).

[0088] When this embodiment is applied in practice, since the folding link 12 and the second link 13 can rotate around the rotation axis (the first middle finger joint rotation axis 11 and the second middle finger joint rotation axis 15) respectively, when the first driving member rotates, the first screw 4 will extend or shorten axially in the first nut 5. The shortening of the first screw 4 will cause the push head 26 to shorten axially, pulling the four-bar linkage composed of the folding link 12 and the second link 13 to rotate counterclockwise relative to the middle finger joint shell (the shell where the first middle finger joint rotation axis 11 and the second middle finger joint rotation axis 15 are located, not shown in the figure), and the fingertip link 16 is coupled and rotated, corresponding to the bending movement of the fingertip 18. On the contrary, the extension of the first screw 4 will cause the push head 26 to shorten axially. The axial extension pushes the folding link 12, the four-bar linkage composed of the second link 13 rotates clockwise relative to the middle finger joint shell, and the fingertip link 16 couples and rotates in the opposite direction, corresponding to the extension movement of the fingertip joint 18. The above can complete the coupling movement of the fingertip joint 18 of the multi-finger mechanical finger, and due to the cooperation of the first universal joint coupling 3 and the first screw 4, as well as the cooperation of the second universal joint coupling 20 and the second screw 21, the angle change of the coupled multi-finger mechanical fingertip joint 18 can be independent of the change of the pitch (corresponding to the cooperation of the first universal joint coupling 3 and the first screw 4) or the side swing (corresponding to the cooperation of the second universal joint coupling 20 and the second screw 21) of the proximal finger joint frame 6.

[0089] like Figure 2-Figure 5 As shown, as an optional embodiment of the present invention, the base joint frame 2 rotates around the proximal knuckle frame 6 within an angle ranging from 0° to 90°.

[0090] like Figure 12 As shown, combined with the characteristics of the mechanism in the present invention, the efficiency of the universal joint decreases with the increase of the working angle (the universal joint efficiency experience curve is shown in FIG. Figure 10 As shown in the figure, through mechanism design and mechanism parameter optimization, the finger (fingertip joint 18) maintains high efficiency in the range of 0-30° (high efficiency means mechanism efficiency is above 80%), and can self-lock in the range of 30°-90° (force applied to the end of the finger cannot make the joint move), so that the finger mechanism is in a low-efficiency range when lifting objects and can passively bear the load by self-locking; the finger mechanism is in a high-efficiency range when it is straight and bent at a small angle, saving energy.

[0091] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but is to be construed in the widest possible manner consistent with the principles and novel features disclosed herein.

[0092] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A cross-joint transmission mechanism, characterized in that: Used to drive the fingertip (18) to bend or stretch, including: A base joint frame (2) and a proximal knuckle frame (6) are arranged in sequence, and the proximal knuckle frame (6) is rotatably connected to the base joint frame (2); a first universal joint coupling (3) disposed between the base joint frame (2) and the proximal knuckle frame (6); A first screw pair, the first screw pair comprises a first screw (4) and a first nut (5) in threaded engagement, the first nut (5) being fixedly connected to the proximal finger joint frame (6), one end of the first screw (4) being slidably connected to the output end of the first universal joint coupling (3), the input end of the first universal joint coupling (3) being drivingly connected to the first rotating drive member (1), the other end of the first screw (4) being connected to the finger joint (18) via a push head (26), so that the first screw (4) slides axially relative to the output end of the first universal joint coupling (3) when rotating with the first universal joint coupling (3), thereby driving the push head (26) to move, so that the finger joint (18) is bent or stretched; The push head (26) includes a bearing housing (7), a bearing cover (8) and a bearing arranged in the bearing housing (7), the bearing including a bearing inner ring (23) and a bearing outer ring (24) that cooperate with each other, the bearing inner ring (23) is fixedly connected to the other end of the first lead screw (4), the bearing outer ring (24) is fixedly connected to the bearing housing (7), the bearing cover (8) is fixedly connected to the bearing housing (7), and the bearing cover (8) is also movably connected to the fingertip joint (18); The base joint frame (2) further comprises a second mounting portion (10), the base joint frame (2) comprises a frame body (27) and a first mounting portion (25), the frame body (27) and the first mounting portion (25) are fixedly connected, the second mounting portion (10) is rotatably connected to the first mounting portion (25), the proximal knuckle frame (6) is rotatably connected to the second mounting portion (10), the two rotating shafts at the two corresponding rotating connections of the second mounting portion (10) are not parallel, the input end of the first universal joint coupling (3) is rotatably connected to the output shaft of the first rotating drive member (1), and the output shaft of the first rotating drive member (1) is rotatably arranged relative to the frame body (27); At least one set of mutually matched second universal joint couplings (20) and second screw pairs is provided between the base joint frame (2) and the proximal knuckle frame (6); for each set of the second universal joint couplings (20) and the second screw pairs, the second screw pairs include a second screw (21) and a second nut (22) that are threadedly matched; the second nut (22) is fixedly connected to the proximal knuckle frame (6); the second universal joint coupling (20) is driven by a second rotating drive member (19) and drives the second screw (21) to rotate to generate feed relative to the proximal knuckle frame (6); the input end of the second universal joint coupling (20) is drivingly connected to the output shaft of the second rotating drive member (19), and the output shaft of the second rotating drive member (19) is rotatably arranged relative to the frame body (27).

2. The cross-joint transmission mechanism according to claim 1, characterized in that: The first universal joint coupling (3) includes a double universal joint, and the double universal joint includes a first joint head (31), a double fork (32) and a second joint head (33) that cooperate with each other and are arranged in sequence. The input end of the first universal joint coupling (3) includes the first joint head (31), and the output end of the first universal joint coupling (3) includes the second joint head (33). The second joint head (33) is provided with a non-circular slideway at one end close to the first lead screw (4), and the first lead screw (4) is provided with a head matching the non-circular slideway at one end. The first rotating drive member (1) is drivingly connected to the first joint head (31) to drive the double universal joint to rotate relative to the base joint frame (2) and drive the first lead screw (4) to move.

3. The cross-joint transmission mechanism according to claim 1, characterized in that: The other end of the first lead screw (4) is fixedly connected to the push head (26), and the push head (26) is movably connected to the fingertip joint (18).

4. The cross-joint transmission mechanism according to claim 1, characterized in that: The bearing cover (8) is fixedly connected to the bearing housing (7), and the inner end of the bearing cover (8) abuts against the bearing outer ring (24).

5. The cross-joint transmission mechanism according to claim 1, characterized in that: When two parallel sets of the second universal joint couplings (20) and the second screw pairs are provided between the base joint frame (2) and the proximal knuckle frame (6), if the two second screws (21) in the two sets of the second universal joint couplings (20) and the second screw pairs generate feed directions relative to the proximal knuckle frame (6) in opposite directions, the second mounting portion (10) rotates relative to the first mounting portion (25); if the two second screws (21) in the two sets of the second universal joint couplings (20) and the second screw pairs generate feed directions relative to the proximal knuckle frame (6) in the same direction, the proximal knuckle frame (6) rotates relative to the second mounting portion (10) and the base joint frame (2); or, when one set of the second universal joint couplings (20) and the second screw pair is provided and the second screw (21) generates feed relative to the proximal knuckle frame (6), the proximal knuckle frame (6) rotates relative to the second mounting portion (10) and the base joint frame (2).

6. The cross-joint transmission mechanism according to claim 1, characterized in that: The angle of rotation of the proximal knuckle frame (6) around the base joint frame (2) includes 0-90 degrees.

7. A mechanical finger, characterized in that: The invention comprises a cross-joint transmission mechanism according to any one of claims 1 to 6, further comprising a fingertip section (18), wherein the fingertip section (18) comprises: a first connecting rod (14), one end of which is hinged to a bearing cover (8) in the cross-joint transmission mechanism; a second connecting rod (13), one end of which is hinged to the proximal knuckle frame (6) in the cross-joint transmission mechanism; A folding connecting rod (12), one end of which is hinged to the proximal knuckle frame (6) and the other end of the first connecting rod (14); A fingertip link (16), one end of which is hinged to the other end of the folding link (12) and the other end of the second link (13), and the other end of the fingertip link (16) is a free end.

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