CN116277124A - Bipedal robot and hip joint structure thereof - Google Patents

Abstract

The application belongs to the technical field of intelligent robots, and particularly relates to a bipedal robot and a hip joint structure thereof. The hip joint structure includes: the hip switching structure comprises a first switching part and a second switching part which are fixedly connected with each other, and the second switching part is used for connecting the leg structures of the bipedal robot; the first driving mechanism is fixedly arranged on the second switching part and is used for driving the leg structure to swing sideways; the second driving mechanism is fixedly connected with the output rotating shaft of the first driving mechanism, the end part of the leg structure is connected with the output rotating shaft of the second driving mechanism, the axial direction of the output rotating shaft of the second driving mechanism is orthogonal to the axial direction of the output rotating shaft of the first driving mechanism, and the second driving mechanism is used for driving the leg structure to rotate. By the technical scheme, the problem that the hip joint of the biped robot is quite bulky due to complex structural design of the hip joint in the existing biped robot is solved.

Description

Bipedal robot and hip joint structure thereof

Technical Field

The application belongs to the technical field of intelligent robots, and particularly relates to a bipedal robot and a hip joint structure thereof.

Background

With the progress of science and technology, various industries are increasingly applied to intelligent robots, and particularly, the application popularity of intelligent robots corresponding to service industries is relatively higher. Previously, the form of the intelligent robot is relatively simple, for example, a traveling system of the intelligent robot is generally replaced by a wheel type motion system. However, intelligent robots are now increasingly tending to mimic human-shaped designs, and so bipedal robots have emerged.

Any single leg of the humanoid biped robot should comprise corresponding leg joints such as hip joints, knee joints, ankle joints and the like, and the leg joints are mutually matched to finish walking motions similar to human motions. Since the hip joint is a receiving joint between the upper body of the robot and the lower body of the robot, the degree of freedom of movement involved in the hip joint is one of the relatively large number of leg joints. In the existing biped robot, the hip joint is not only responsible for left and right swinging of the upper body of the robot, but also for left and right twisting of the upper body of the robot, and simultaneously is also responsible for alternating front and back strides of the two legs of the lower body of the robot and left and right swinging of any one leg of the two legs. In order to realize the motion of each degree of freedom, the structure of the hip joint is designed to be quite complex by the current bipedal robot design, and the motion of each degree of freedom is realized by adopting the cooperation of complicated motion mechanisms, so that the hip joint of the current bipedal robot is quite bulky, commonly called a water barrel waist, and is quite different from the aesthetic concept of people on humanoid robots.

Disclosure of Invention

The purpose of the application is to provide a biped robot and hip joint structure thereof, and aims to solve the problem that the hip joint of the biped robot is quite bulky due to complex structural design of the hip joint in the existing biped robot.

In order to achieve the above purpose, the technical scheme adopted in the application is as follows: a hip joint structure of a biped robot, comprising:

the hip switching structure comprises a first switching part and a second switching part which are fixedly connected with each other, and the second switching part is used for connecting the leg structures of the bipedal robot;

the first driving mechanism is fixedly arranged on the second switching part and is used for driving the leg structure to swing sideways;

the second driving mechanism is used for driving the leg structure to rotate around the axis of the output rotating shaft of the second driving mechanism, and the second driving mechanism is mounted on the second switching part.

In one embodiment, the first transfer portion and the second transfer portion are both plate-shaped members, the extending direction of the first transfer portion and the extending direction of the second transfer portion are orthogonally arranged, and the extending direction of the first transfer portion is substantially horizontal; the first driving mechanism and the second driving mechanism are respectively positioned at two sides of the second switching part, the second switching part is provided with an assembly hole, and an output rotating shaft of the first driving mechanism passes through the assembly hole and is connected with the second driving mechanism.

In one embodiment, the hip joint structure further comprises a hip flange member fixedly connected to the output shaft of the first drive mechanism and a hip support member fixedly connected to the hip flange member, the second drive mechanism being mounted to the hip support member.

In one embodiment, the hip joint structure further comprises a third driving mechanism and a leg switching member, the leg switching member is fixedly connected to the output shaft of the second driving mechanism, the third driving mechanism is mounted on the leg switching member, the axis direction of the output shaft of the third driving mechanism and the axis direction of the output shaft of the first driving mechanism are all orthogonally arranged, and the leg structure is fixedly connected to the output shaft of the third driving mechanism.

In one embodiment, the third drive mechanism is located outside of the leg switch member.

According to another aspect of the present application, a bipedal robot is provided. Specifically, the biped robot includes:

a leg structure; and

the hip joint structure, the leg structure and the hip joint structure of the bipedal robot as described above are connected.

In one embodiment, the thigh limb has a first end connected to the hip joint structure; a lower leg part is rotatably arranged at a second end of the thigh limb, and a first connecting end is arranged at the end part of the lower leg part, which is close to the thigh limb; the knee driving mechanism is fixedly arranged at one end, close to the hip joint structure, of the thigh limb; the output rotating shaft of the knee driving mechanism is in driving connection with the first end of the first knee connecting rod, and the second end of the first knee connecting rod is in rotating connection with the first connecting end.

In one embodiment, the leg structure further comprises a sole portion provided with first and second spaced apart connection seats; the lower leg portion includes: the first end of the shank is rotatably arranged at the second end of the thigh, the second end of the shank is movably connected with the first connecting seat, and the second end of the shank is provided with a first connecting end in an extending way; the first shank driving mechanism is arranged on the shank; the output rotating shaft of the first calf driving mechanism is in driving connection with the first end of the first calf connecting rod, and the second end of the first calf connecting rod is in rotating connection with the second connecting seat.

In one embodiment, the lower leg further comprises a second lower leg driving mechanism and a second lower leg connecting rod, the second lower leg driving mechanism is mounted on the lower leg limb, the output rotating shaft of the second lower leg driving mechanism is in driving connection with the first end of the second lower leg connecting rod, the second end of the second lower leg connecting rod is in rotating connection with the second connecting seat, and the first lower leg connecting rod and the second lower leg connecting rod are arranged in parallel.

In one embodiment, the leg structure further comprises an ankle connecting member, the ankle connecting member is provided with a first connecting head, a second connecting head, a third connecting head and a fourth connecting head, a connecting line of the first connecting head and the second connecting head is perpendicular to a connecting line of the third connecting head and the fourth connecting head, the second end of the shank is provided with a first connecting ear and a second connecting ear which are opposite and spaced, the first connecting seat comprises a first ankle connecting ear and a second ankle connecting ear which are opposite and spaced, the connecting line of the first ankle connecting ear and the second ankle connecting ear is perpendicular to a connecting line of the first connecting ear and the second connecting ear, the first connecting head is rotationally connected with the first connecting ear, the second connecting head is rotationally connected with the second connecting ear, the fourth connecting head is rotationally connected with the first ankle connecting ear, and the third connecting head is rotationally connected with the second ankle connecting ear.

The application has at least the following beneficial effects:

the application of the hip joint structure that this application provided utilizes hip switching structure as the support of taking up and down, switching platform comes to assemble robot's upper body part and leg structure, and leg structure carries out switching to hip switching structure through first actuating mechanism and second actuating mechanism, in the execution hip joint motion process, can drive the leg structure through first actuating mechanism and use the axis of first actuating mechanism's output pivot to carry out two degrees of freedom motions (i.e. leg structure carries out the side pendulum) of side-to-side pendulum leg as the axis of rotation, can drive the leg structure through second actuating mechanism and use the axis of second actuating mechanism's output pivot to carry out clockwise rotation or anticlockwise rotation's two degrees of freedom commentaries on classics leg motion (i.e. leg structure carries out the rotation). Therefore, the multi-degree-of-freedom movement capability of the hip joint is realized, and the hip joint structure provided by the application has the advantages that the number of the adopted component parts is small, the structure is simple, and compared with the existing biped robot, the volume of the hip joint can be effectively reduced, so that the humanoid outline form of the biped robot is more in line with aesthetic sense of people.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required for the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic view of an assembly structure of a hip joint structure and two legs in a bipedal robot according to an embodiment of the application, wherein the hip joint structure is in a partially exploded state;

fig. 2 is a schematic diagram of a hip joint structure and an assembling structure of two legs in the bipedal robot according to the embodiment of the application, wherein the hip joint structure is in a partially exploded state;

fig. 3 is a schematic structural view of a left leg and a part of a hip joint structure corresponding to the left leg in the bipedal robot according to the embodiment of the application;

fig. 4 is a schematic diagram III of an assembly structure of a hip joint structure and two legs in the bipedal robot of the embodiment, wherein the left leg is in an exploded state;

fig. 5 is a schematic structural view of a left leg and a part of a hip joint structure corresponding to the left leg in the bipedal robot according to the embodiment of the application, wherein the left leg is in an exploded state;

FIG. 6 is a schematic view of an assembled structure of an ankle connecting member in a biped robot according to an embodiment of the present application;

fig. 7 is an exploded view of fig. 6.

Wherein, each reference sign in the figure:

121. a left leg; 122. a right leg; 110. a hip joint structure; 111. a first transfer section; 112. a second switching part; 1121. a fitting hole; 130. a first driving mechanism; 140. a second driving mechanism; 151. a hip flange member; 152. a hip support member; 160. a third driving mechanism; 170. a leg switching member;

200. thigh section; 210. thigh limbs; 211. an accommodation space; 220. a knee driving mechanism; 230. a first knee link; 231. a first pole segment; 232. a second pole segment; 233. a third pole segment; 240. a second knee link; 251. a first knee pin; 252. a second knee pin;

300. a lower leg portion; 310. shank; 320. a first calf drive mechanism; 330. a first lower leg link; 340. a second calf drive mechanism; 350. a second lower leg link; 360. a third shank link; 370. a fourth shank link; 380. the connecting rotating shaft; 381. a first calf pin; 382. a second calf pin; 383. a third shank pin; 384. a fourth shank pin; 390. a pivot; 391. a first limiting block; 3911. the first limiting notch; 392. a second limiting block; 3921. the second limiting notch; 301. a first pole segment; 302. a second pole segment; 303. a third pole segment; 304. a first connection lug; 305. a second connecting ear; 311. a first connection end;

400. Sole portion; 401. a first connection base; 402. a second connecting seat; 411. a first ankle connection lug; 412. a second ankle connecting lug; 420. an ankle connection member; 421. a first connector; 422. a second connector; 423. a third connector; 424. a fourth connector; 4201. a first cross member; 4202. a second cross member; 4203. a longitudinal shaft member; 42031. perforating; 4204. a fixing bolt; 431. a first bearing; 432. a second bearing; 433. a third bearing; 434. and a fourth bearing.

Detailed Description

Embodiments of the present application are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and intended for the purpose of explaining the present application and are not to be construed as limiting the present application.

In the description of the present application, it should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate description of the present application and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present application.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first", "a second", etc. may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

In this application, unless specifically stated and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art as the case may be.

The bipedal robot comprises a hip joint structure, wherein the hip joint structure is a bearing switching part between an upper body part and a lower body part (namely, two legs, and one of the two legs is a leg structure) of the robot, so that the hip joint is assembled and formed, and is one of important joints of the humanoid robot. In particular, as shown in fig. 1-5, the hip joint structure includes a hip adapter structure 110, a first drive mechanism 130, and a second drive mechanism 140. The hip joint structure 110 includes a first joint part 111 and a second joint part 112 fixedly connected to each other, the first joint part 111 is used for mounting and supporting an upper body part of the robot, and the second joint part 112 is used for supporting and connecting leg structures of the bipedal robot. The left leg 121 and the right leg 122 of the two legs are symmetrically arranged relative to the symmetry plane of the hip joint structure 110, that is, the left leg 121 and the right leg 122 are both leg structures, the structures of the two legs are identical, and accordingly, the first driving mechanism 130 and the second driving mechanism 140 are respectively arranged in two, corresponding to the left leg 121 and the right leg 122. The first drive mechanism 130, the second drive mechanism 140, etc. of one of the leg structures and the corresponding hip joint structure will be described below.

The first driving mechanism 130 is fixedly mounted on the second adapting portion 112, and when the first driving mechanism 130 is assembled on the second adapting portion 112, the axis extending direction of the output rotating shafts of the first driving mechanism 130 is substantially horizontal (and the axis extending directions of the output rotating shafts of the two first driving mechanisms 130 are substantially parallel). The second driving mechanism 140 is fixedly connected to the output shaft of the first driving mechanism 130, and when the second driving mechanism 140 is assembled, the axis extending direction of the output shaft of the second driving mechanism 140 is substantially perpendicular to the axis extending direction of the output shaft of the corresponding first driving mechanism 130, that is, the axis direction of the output shaft of the second driving mechanism 140 and the axis direction of the output shaft of the first driving mechanism 130 are orthogonally arranged. The ends of the leg structure are then connected to the output shaft of the second drive mechanism 140.

The application of the hip joint structure provided by the application utilizes the hip joint structure 110 as a support and a joint platform for supporting and starting up and down to assemble the upper body part and the leg structure of the robot, and the leg structure is connected to the hip joint structure through the first driving mechanism 130 and the second driving mechanism 140, in the process of executing hip joint movement, the leg structure can be driven by the first driving mechanism 130 to perform two-degree-of-freedom movement (namely, the leg structure performs side swinging) of swinging legs left and right by taking the axis of the output rotating shaft of the first driving mechanism 130 as a rotating axis, and the leg structure can be driven by the second driving mechanism 140 to perform two-degree-of-freedom leg swinging movement (namely, the leg structure performs rotating) of clockwise rotation or anticlockwise rotation by taking the axis of the output rotating shaft of the second driving mechanism 140 as the rotating axis. Therefore, the multi-degree-of-freedom movement capability of the hip joint is realized, and the hip joint structure provided by the application has the advantages that the number of the adopted component parts is small, the structure is simple, and compared with the existing biped robot, the volume of the hip joint can be effectively reduced, so that the humanoid outline form of the biped robot is more in line with aesthetic sense of people.

To achieve a relative flexion-extension movement (i.e. a squat or bow movement, in particular a squat movement) between the leg structure and the upper body part of the robot, the hip joint structure thus also comprises a third drive mechanism 160 and a leg changeover member 170, as shown in fig. 1 to 5. In a specific assembly, the leg switching member 170 is fixedly connected to the output shaft of the second driving mechanism 140, and the third driving mechanism 160 is fixedly mounted on the leg switching member 170. When the third driving mechanism 160 is assembled, the axis extending direction of the output shaft of the third driving mechanism 160 and the axis extending direction of the output shaft of the first driving mechanism 130 are substantially perpendicular to each other, and the axis extending direction of the output shaft of the third driving mechanism 160 and the axis extending direction of the second driving mechanism 140 are substantially perpendicular to each other. The end of the leg structure is fixedly connected to the output shaft of the third drive mechanism 160. In the squatting movement, taking the left leg 121 as an example, as shown in fig. 3, the third driving mechanism 160 is started and outputs a rotational power to the end of the left leg 121, so that the left leg 121 rotates relative to the leg switching member 170 with the axis of the output rotary shaft of the third driving mechanism 160 as the rotation axis, thereby achieving two degrees of freedom movement of squatting and restoring to erection.

In the present embodiment, the third drive mechanism 160 is located outside of the leg switching member 170 (i.e., outside of the thigh). That is, the third driving mechanism 160 corresponding to the left leg 121 is located on the side of the left leg 121 facing away from the right leg 122, and the third driving mechanism 160 corresponding to the right leg 122 is located on the side of the right leg 122 facing away from the left leg 121. Taking the left leg 121 as an example, as shown in fig. 3, the assembled third driving mechanism 160 is located on the outer side of the left leg 121 near the hip joint, and basically belongs to the position with the largest outer diameter of thigh muscle of the left leg 121, so after the thigh shell is assembled on the left leg 121 to wrap the third driving mechanism 160, the outline of the position is plump, and more approaches to the outline of the humanoid thigh, and the line of the thigh is more attractive.

Further, as shown in fig. 1 and fig. 2, the first adapter portion 111 and the second adapter portion 112 are plate-shaped members, the extending direction of the first adapter portion 111 and the extending direction of the second adapter portion 112 are orthogonally arranged, and the extending direction of the first adapter portion 111 is substantially horizontal, so that the arrangement form of the hip adapter structure 110 is more matched with the humanoid waist form, the first adapter portion 111 in the substantially horizontal state is more convenient for supporting and installing the upper body part of the robot, and the second adapter portion 112 in the substantially vertical state is also more convenient for adapting and installing the legs of the bipedal robot. The first driving mechanism 130 and the second driving mechanism 140 are respectively located at two sides of the second adapting portion 112, the second adapting portion 112 is provided with an assembly hole 1121, and an output rotation shaft of the first driving mechanism 130 passes through the assembly hole 1121 and is fixedly connected with the second driving mechanism 140. Thus, the assembled two first driving mechanisms 130 are positioned at the hip positions of the bipedal robot, and after the hip shells of the robot are wrapped, the hip positions of the robot can be plump and beautiful.

In order to improve the assembly efficiency and reduce the assembly difficulty, therefore, as shown in fig. 1 to 5, the hip joint structure further includes a hip flange member 151 and a hip support member 152, and the first driving mechanism 130 and the second driving mechanism 140 are mounted through the hip flange member 151 and the hip support member 152 in a transfer manner. Specifically, the hip flange member 151 is fixedly connected to the output shaft of the first driving mechanism 130, the hip support member 152 is fixedly connected to the hip flange member 151, and the second driving mechanism 140 is fixedly mounted to the hip support member 152.

The leg structure of the biped robot provided herein includes a thigh limb 210, a shank 300, a knee drive mechanism 220, and a first knee link 230. The thigh limb 210 and the shank 300 form a limb main body structure of a leg structure, wherein the thigh limb 210, the knee drive mechanism 220, and the first knee link 230 constitute the thigh 200 of the leg structure of the bipedal robot.

As shown in fig. 1 to 5, a first end of the thigh limb 210 is coupled to an output shaft of the third driving mechanism 160 of the hip joint structure, and the shank 300 is rotatably mounted to a second end of the thigh limb 210 through a coupling shaft 380 (i.e., between the shank 300 and the second end of the thigh limb 210 is hinged through the coupling shaft 380), and a knee joint (i.e., a knee portion) is assembled between the thigh limb 210 and the shank 300, so that flexion and extension movement between the thigh limb 210 and the shank 300 can be achieved. Further, the lower leg 300 has a first connection end 311 at an end thereof adjacent to the thigh 210, and the knee driving mechanism 220 is fixedly mounted to an end of the thigh 210 adjacent to the hip joint structure. When the knee driving mechanism 220 is fixedly mounted to the thigh 210, an axis extending direction of an output shaft of the knee driving mechanism 220 is substantially horizontal and substantially perpendicular to a forward direction of the robot, and the output shaft of the knee driving mechanism 220 is drivingly connected to a first end of the first knee link 230, and a second end of the first knee link 230 is rotatably connected to the first connecting end 311. The knee driving mechanism 220 moves the first knee link 230, and then the first knee link 230 pulls the first connection end 311, so that the lower leg 300 rotates relative to the thigh limb 210 with the axis of the connection shaft 380 as the rotation axis, thereby performing flexion and extension movements of the knee joint.

Compared with the prior art, the biped robot has the advantages that the rotating motor for connecting the thigh limb and the shank in the leg structure of the biped robot is directly assembled at the knee part, the biped robot moves the assembling position of the knee driving mechanism 220 to the first end, close to the hip joint structure, of the thigh limb 210, so that the volume of the knee joint formed by assembling the shank 300 and the second end of the thigh limb 210 can be reduced, and the knee part of the humanoid knee with compact and small structure can be obtained on the basis of ensuring the flexion and extension movement between the thigh limb 210 and the shank 300. In addition, the knee driving mechanism 220 having moved up the installation position is just located at the position of the maximum outer diameter of the thigh limb 210, that is, the thigh position where the human thigh muscle is most developed, so that when the shell is assembled for the thigh limb 210, not only the assembly space of the thigh part is reasonably utilized, but also the part where the knee driving mechanism 220 is assembled can approach to the thigh muscle line, so that the leg structure of the biped robot is more beautiful.

As shown in fig. 3 to 5, the leg structure further includes a second knee link 240, and a driving connection is made between the output rotation shaft of the knee driving mechanism 220 and the first knee link 230 through the second knee link 240. Specifically, a first end of the second knee link 240 is fixedly coupled to the output shaft of the knee drive mechanism 220, and a second end of the second knee link 240 is rotatably coupled to the first end of the first knee link 230. The knee driving mechanism 220 drives the second knee link 240 to move, then the second knee link 240 drives the first knee link 230 to move, and then the first knee link 230 drives the first connecting end 311, so that the lower leg 300 rotates relative to the thigh limb 210 with the axis of the connecting rotating shaft 380 as the rotation axis, and the leg bending and stretching movement is performed.

As shown in fig. 4, the second end of the second knee link 240 is hinged to the first end of the first knee link 230 by a first knee pin 251. Further, the second end of the first knee link 230 is hinged to the first connection end 311 through the second knee pin 252. During the flexion and extension movement of any one leg, the second end of the second knee link 240 and the first end of the first knee link 230 relatively rotate about the axis of the first knee pin 251, and the second end of the first knee link 230 and the first connecting end 311 relatively rotate about the axis of the second knee pin 252.

Alternatively, in another embodiment of the present application, one of the second end of the second knee link 240 and the first end of the first knee link 230 is provided with a first knee ball (not shown), and the other of the second end of the second knee link 240 and the first end of the first knee link 230 is provided with a first knee socket structure (not shown) to which the first knee ball is hinged. Further, one of the second end and the first connecting end 311 of the first knee link 230 is provided with a second knee ball (not shown), and the other of the second end and the first connecting end 311 of the first knee link 230 is provided with a second knee socket structure (not shown), to which the second knee ball is hinged.

As shown in fig. 4, the first knee link 230 of the embodiment of the present application includes a first bar section 231, a second bar section 232, and a third bar section 233, i.e., the first knee link 230 is a combined bar, and the overall length of the first knee link 230 can be adjusted, thereby enabling the first knee link 230 to be more precisely assembled between the second knee link 240 and the first connection end 311, eliminating an assembly gap generated by a dimensional chain error between the first knee link 230 and the second knee link 240, and eliminating an assembly gap generated by a dimensional chain error between the first knee link 230 and the first connection end 311. Specifically, the first and third rod segments 231 and 233 are respectively screwed to both ends of the second rod segment 232, and the threads of the first and third rod segments 231 and 233 are reversed with respect to each other.

After the hinge connection between the lower leg 300 and the second end of the thigh limb 210 is completed through the connection shaft 380 and the knee driving mechanism 220 is fixedly installed to the thigh limb 210 and the second knee link 240 is fixedly connected to the output shaft of the knee driving mechanism 220, when the first knee link 230 is assembled, the length of the first knee link 230 is adjusted to an appropriate assembly length according to the assembly size chain between the second knee link 240 and the first connection end 311, and then both ends of the first knee link 230 are hinged to the second end of the second knee link 240 and the first connection end 311 through the first knee pin 251 and the second knee pin 252, respectively. Then, depending on whether the length of the first knee link 230 is in a slightly long state of being tightly fitted between the second knee link 240 and the first connection end 311 or in a slightly short state of being tightly fitted between the second knee link 240 and the first connection end 311 at this time, the second rod section 232 is rotated such that the first rod section 231 and the third rod section 233 are brought closer to each other with respect to the second rod section 232 to shorten the entire length of the first knee link 230 or are brought away from each other to lengthen the entire length of the first knee link 230, so that the fitting length of the first knee link 230 is optimized.

As shown in fig. 4 and 5, the thigh limb 210 is provided with an accommodation space 211, the first knee link 230 and the second knee link 240 are both located in the accommodation space 211, and the first connection end 311 extends into the accommodation space 211. In this way, the accommodation space 211 is used to accommodate and assemble the first knee link 230 and the second knee link 240, so that the overall assembly structure of the thigh 200 is more compact.

The leg structure of the biped robot further comprises a sole part 400, wherein the sole part 400 is provided with a first connecting seat 401 and a second connecting seat 402 which are spaced, and the extending direction of a connecting line between the first connecting seat 401 and the second connecting seat 402 is the same as the advancing direction of the robot. The lower leg 300 of the leg structure of the bipedal robot powers the motion of the sole 400. As shown in fig. 3 to 5, the lower leg 300 includes a lower leg limb 310, a first lower leg driving mechanism 320, and a first lower leg link 330, which constitute the main constituent parts of the lower leg 300. In the specific assembly, the first end of the shank 310 is rotatably mounted on the second end of the thigh limb 210, the second end of the shank 310 is movably connected with the first connecting seat 401, and the second end of the shank 310 is provided with a first connecting end 311 in an extending manner. Thus, the ankle joint of the human ankle is formed by fitting between the shank 310 and the sole 400. Further, the first calf driving mechanism 320 is fixedly mounted on the calf limb 310, and when the first calf driving mechanism 320 is assembled, the axis extending direction of the output shaft of the first calf driving mechanism 320 is substantially horizontal and substantially perpendicular to the advancing direction of the robot. The output shaft of the first calf drive mechanism 320 is drivingly connected to the first end of the first calf link 330, and the second end of the first calf link 330 is rotatably connected to the second coupling mount 402. Thus, the first calf driving mechanism 320 is started to enable the output rotating shaft to output rotating power, so as to drive the first calf connecting rod 330 to move, and then the first calf connecting rod 330 drives the sole portion 400 to perform sole lifting motion by taking an ankle joint structure formed by assembling the calf limb 310 and the sole portion 400 as a rotating fulcrum through the second connecting seat 402, wherein the sole lifting motion comprises two degrees of freedom motions of lifting and lowering the sole.

In the bipedal robot provided by the application, the lower leg 300 specifically drives the sole portion 400 to perform sole lifting motion through power transmission of the first lower leg driving mechanism 320 and the first lower leg link 330. Because the first shank link 330 is a rigid rod, not only traction power for lifting the sole 400 can be transmitted to the sole 400, but also pushing force for lowering the sole 400 can be transmitted to the sole 400, that is, the shank 300 of the bipedal robot can realize power transmission for sole lifting motion by simply designing and assembling a group of transmission structures of the first shank drive mechanism 320 and the first shank link 330. Compared with the existing biped robot, the biped robot has fewer component parts and simpler structure of the lower leg 300, so that the assembly difficulty is greatly reduced, and the assembly efficiency is remarkably improved.

As shown in fig. 4 and 5, the lower leg 300 further includes a third lower leg link 360, and the driving connection between the output rotation shaft of the first lower leg driving mechanism 320 and the first end of the first lower leg link 330 is achieved by the third lower leg link 360. Specifically, a first end of the third calf link 360 is fixedly coupled to the output shaft of the first calf drive mechanism 320 and a second end of the third calf link 360 is rotatably coupled to the first end of the first calf link 330. Thus, when the first calf driving mechanism 320 is started to enable the output shaft to output rotation power, the output shaft drives the third calf link 360 to swing by taking the axis of the output shaft as the rotation axis, so as to drive the first calf link 330 to move, and then the first calf link 330 drives the sole portion 400 to perform sole lifting movement by taking the ankle joint formed by assembling the calf limb 310 and the sole portion 400 as a rotation pivot through the second connecting seat 402.

Further, as shown in fig. 4 and 5, the lower leg 300 further includes a second lower leg driving mechanism 340 and a second lower leg link 350. The second calf driving mechanism 340 is fixedly mounted on the calf limb 310, and when the second calf driving mechanism 340 is assembled, the axis extending direction of the output rotating shaft of the second calf driving mechanism 340 is substantially horizontal and substantially perpendicular to the advancing direction of the robot. The output shaft of the second lower leg driving mechanism 340 is drivingly connected to the first end of the second lower leg link 350, and the second end of the second lower leg link 350 is rotatably connected to the second connecting base 402. Further, the first and second shank links 330 and 350 are juxtaposed in a direction perpendicular to the advancing direction of the robot. In this way, the group of transmission structures formed by the second calf drive mechanism 340 and the second calf link 350 and the group of transmission structures formed by the first calf drive mechanism 320 and the first calf link 330 are arranged in parallel, and the two groups of transmission structures together provide power to the sole part 400 at the same time to drive the sole part 400 to perform sole lifting motion. This allows the first and second lower leg drive mechanisms 320, 340 to be powered by a relatively low power rated power device (e.g., a relatively low power rated motor), and thus the device volumes of the first and second lower leg drive mechanisms 320, 340 are relatively low, resulting in a lower overall lower leg 300 and a lower leg 300 profile that more closely approximates the profile of a human lower leg.

As shown in fig. 4 and 5, the lower leg 300 further includes a fourth lower leg link 370, and the driving connection between the output rotation shaft of the second lower leg driving mechanism 340 and the first end of the second lower leg link 350 is achieved by the fourth lower leg link 370. Specifically, the first end of the fourth calf link 370 is fixedly coupled to the output shaft of the second calf drive mechanism 340 and the second end of the fourth calf link 370 is rotatably coupled to the first end of the second calf link 350. Thus, when the second calf driving mechanism 340 is started to make the output shaft output rotational power, the output shaft drives the fourth calf link 370 to swing with the axis of the output shaft as the rotational axis, thereby driving the second calf link 350 to move, and then the second calf link 350 drives the sole portion 400 to perform sole lifting motion by using the ankle joint formed by assembling the calf limb 310 and the sole portion 400 as the rotational pivot through the second connecting seat 402.

In the embodiment of the present application, as shown in fig. 4 and 5, the second end of the third shank link 360 is hinged to the first end of the first shank link 330 by the first shank pin 381, and the second end of the fourth shank link 370 is hinged to the first end of the second shank link 350 by the second shank pin 382. During the sole lifting movement, the second end of the third shank link 360 and the first end of the first shank link 330 rotate relative to each other about the axis of the first shank pin 381, and the second end of the fourth shank link 370 and the first end of the second shank link 350 rotate relative to each other about the axis of the second shank pin 382.

As shown in fig. 4 and 5, the lower leg 300 further includes a pivot 390 rotatably penetrating the second connection base 402, the second end of the first lower leg link 330 is rotatably connected to one end of the pivot 390, and the second end of the second lower leg link 350 is rotatably connected to the other end of the pivot 390. During the ball lifting motion, the pivot 390 rotates with respect to the ball 400 about its own axis as a rotation axis.

Further, as shown in fig. 4 and 5, the second end of the first calf link 330 is hinged to one end of the pivot 390 via a third calf pin 383, and the second end of the second calf link 350 is hinged to the other end of the pivot 390 via a fourth calf pin 384. That is, the second end of the first lower leg link 330 and one end of the pivot 390 can rotate about the axis of the third lower leg pin 383, and the second end of the second lower leg link 350 and the other end of the pivot 390 can rotate about the axis of the fourth lower leg pin 384. The axis extending direction of the third shank pin 383 and the axis extending direction of the fourth shank pin 384 are parallel to each other and coincide with the traveling direction of the robot. At this time, referring to fig. 1 to 5 in combination, taking the left leg as shown in fig. 3 and 5 as an example, when the sole part 400 needs to perform a right swing sole movement (i.e., sole inner swing), the first calf driving mechanism 320 outputs power driving the first calf link 330 to move downward, and the second calf driving mechanism 340 outputs power driving the second calf link 350 to move upward, so that the sole part 400 swings laterally inward with the connection line of the first connection seat 401 and the second connection seat 402 as a rotation axis. When the sole portion 400 needs to perform left swing sole movement (i.e. sole outward swing), the first calf driving mechanism 320 outputs power for driving the first calf link 330 to move upward, and the second calf driving mechanism 340 outputs power for driving the second calf link 350 to move downward, so that the sole portion 400 performs outward turning swing by taking the connection line of the first connecting seat 401 and the second connecting seat 402 as a rotation axis.

Alternatively, in another embodiment of the present application, one of the second end of the third shank link 360 and the first end of the first shank link 330 is provided with a first shank ball (not shown), and the other of the second end of the third shank link 360 and the first end of the first shank link 330 is provided with a first shank socket (not shown) to which the first shank ball is hinged. Further, one of the second end of the fourth shank link 370 and the first end of the second shank link 350 is provided with a second shank ball (not shown), and the other of the second end of the fourth shank link 370 and the first end of the second shank link 350 is provided with a second shank socket structure (not shown) to which the second shank ball is hinged. Further, one of the second end of the first calf link 330 and one end of the pivot 390 is provided with a third calf ball (not shown), and the other of the second end of the first calf link 330 and one end of the pivot 390 is provided with a third calf socket structure (not shown), the third calf ball being hinged to the third calf socket structure. A fourth calf ball (not shown) is provided at one of the second end of the second calf link 350 and the other end of the pivot 390, and a fourth calf socket structure (not shown) is provided at the other of the second end of the second calf link 350 and the other end of the pivot 390, the fourth calf ball being hinged to the fourth calf socket.

As shown in fig. 5, the first and second shank links 330 and 350 each include the first, second and third rod segments 301, 302 and 303, i.e., the first and second shank links 330 and 350 are each a combined rod, enabling the overall assembly length of the rod to be adjusted, thereby enabling the first and second shank links 330 and 350 to be assembled more precisely. Adjusting the assembly length of the first calf link 330 to eliminate the assembly gap between the first calf link 330, the pivot 390 and the third calf link 360; the assembly length of the second calf link 350 is adjusted to eliminate the assembly gap between the second calf link 350, the pivot 390 and the fourth calf link 370. Specifically, the first shaft section 301 and the third shaft section 303 are respectively screwed to two ends of the second shaft section 302, and the threads of the first shaft section 301 and the threads of the third shaft section 303 are opposite to each other.

Taking the first calf link 330 as an example, after the first calf drive mechanism 320 is fixedly installed to the calf shank 310 and the third calf link 360 is fixedly connected to the output shaft of the first calf drive mechanism 320 and the pivot 390 is installed to the second connecting seat 402, when the first calf link 330 is assembled, the length of the first calf link 330 is adjusted to an appropriate assembly length according to an assembly size chain between the third calf link 360 and the pivot 390, and then both ends of the first calf link 330 are hinged to the second end of the third calf link 360 and the pivot 390 through the first calf pin 381 and the second calf pin 382, respectively. Then, depending on whether the length of the first shank link 330 is in a slightly long state of being tightly fitted between the second end of the third shank link 360 and the pivot 390 or in a slightly short state of being tightly fitted between the second end of the third shank link 360 and the pivot 390 at this time, the second shaft section 302 is rotated so that the first shaft section 301 and the third shaft section 303 are brought close to each other with respect to the second shaft section 302 to shorten the entire length of the first shank link 330 or are brought far away from each other to lengthen the entire length of the first shank link 330, so that the fitting length of the first shank link 330 is optimized.

In the present embodiment, both the first and second calf drive mechanisms 320, 340 are embedded in the calf shank 310, which can make the overall assembly of the calf 300 more compact. The first and second calf drive mechanisms 320 and 340 are arranged at intervals along the extending direction of the calf limb 310, and the extending direction of the output rotation shaft of the first calf drive mechanism 320 extending out of the calf limb 310 is opposite to the extending direction of the output rotation shaft of the second calf drive mechanism 340 extending out of the calf limb 310. This results in a lower overall volume of the lower leg 300, and the contour of the lower leg 300 is more closely approximated to the contour of a human lower leg.

As shown in fig. 4 and 5, the lower leg 300 further includes a first stopper 391, and only the first stopper 391 is provided to the lower leg 300. Specifically, the first limiting block 391 is fixedly mounted on the shank 310 corresponding to the first shank driving mechanism 320, the first limiting block 391 is formed with a first limiting notch 3911, the third shank link 360 extends from the first limiting notch 3911, and two end walls of the first limiting notch 3911 are used for limiting the swing range of the third shank link 360.

Alternatively, as shown in fig. 5, the lower leg 300 further includes a second stopper 392, and only the second stopper 392 is provided to the lower leg 300. Specifically, the second limiting block 392 is fixedly mounted on the shank 310 corresponding to the second shank driving mechanism 340, the second limiting block 392 is formed with a second limiting gap 3921, the third shank link 360 extends from the second limiting gap 3921, and two end walls of the second limiting gap 3921 are used for limiting the swing range of the fourth shank link 370.

Alternatively, the lower leg 300 is provided with the first stopper 391 and the second stopper 392, and the structural form and the assembly form of the first stopper 391 and the second stopper 392 are the same as those described above, so that the description thereof will not be repeated.

The leg structure of the biped robot of the present application further comprises an ankle connection member 420. As shown in fig. 3 to 5, one end of the lower leg portion 300 is used to connect the thigh portion 200 of the bipedal robot, and the lower leg portion 300 and the thigh portion 200 form a limb structure of a leg structure. The other end of the lower leg 300 is provided with opposing and spaced apart first and second attachment ears 304, 305. Correspondingly, the sole portion 400 is provided with a first connecting seat 401, the first connecting seat 401 comprises a first ankle connecting lug 411 and a second ankle connecting lug 412 which are opposite and spaced, and the connecting line of the first ankle connecting lug 411 and the second ankle connecting lug 412 is perpendicular to the connecting line of the first connecting lug 304 and the second connecting lug 305. When the leg 300 is assembled, the ankle connecting member 420 is provided with a first connecting head 421, a second connecting head 422, a third connecting head 423 and a fourth connecting head 424, the connecting line of the first connecting head 421 and the second connecting head 422 is perpendicular to the connecting line of the third connecting head 423 and the fourth connecting head 424, the first connecting head 421 is rotationally connected to the first connecting lug 304, the second connecting head 422 is rotationally connected to the second connecting lug 305, the fourth connecting head 424 is rotationally connected to the first ankle connecting lug 411, and the third connecting head 423 is rotationally connected to the second ankle connecting lug 412.

In this way, the ankle joint structure is formed between the first coupling seat 401 of the ball portion 400 and the end portion of the shank portion 300 by the ankle coupling member 420. During the movement of the sole portion 400, the sole portion 400 can perform two degrees of freedom movements of lifting and dropping the sole by using the connection line between the first connection head 421 and the second connection head 422 as a rotation axis, and the sole portion 400 can perform two degrees of freedom movements of left swing and right swing by using the connection line between the third connection head 423 and the fourth connection head 424 as a rotation axis. That is, the ankle joint structure formed by the assembly of the sole part 400 can basically realize the four degrees of freedom motions of the human-like ankle joint, and basically realize the multi-degree-of-freedom motion function of the ankle joint. Moreover, the simple structure of the ankle connecting member 420 is adopted, so that the volume of the ankle joint can be reduced as much as possible, the volume and the outline form of the ankle joint of the leg structure of the bipedal robot are more similar to those of a human ankle joint, and the aesthetic sense of people is more met.

In this embodiment, as shown in fig. 6 and 7, the first connecting head 421 and the first connecting lug 304 are rotatably connected through a first bearing 431, the second connecting head 422 and the second connecting lug 305 are rotatably connected through a second bearing 432, the fourth connecting head 424 and the first ankle connecting lug 411 are rotatably connected through a fourth bearing 434, and the third connecting head 423 and the second ankle connecting lug 412 are rotatably connected through a third bearing 433. Alternatively, in another embodiment of the present application, the first connection head 421 and the first connection lug 304, the second connection head 422 and the second connection lug 305, the fourth connection head 424 and the first ankle connection lug 411, and the third connection head 423 and the second ankle connection lug 412 are all ball-and-socket joints.

To facilitate the assembly of the ankle connecting member 420 between the first connecting lug 304, the second connecting lug 305, the first ankle connecting lug 411 and the second ankle connecting lug 412, the ankle connecting member 420 is designed in a modular structure as shown in fig. 6 and 7. Specifically, the ankle connection member 420 includes a first transverse member 4201, a second transverse member 4202, and a longitudinal member 4203, one end of the first transverse member 4201 and one end of the second transverse member 4202 are fixedly connected to the longitudinal member 4203, and the axes of the first transverse member 4201 and the second transverse member 4202 are on the same straight line, and the axes of the first transverse member 4201 and the second transverse member 4202 are perpendicular to the axis of the longitudinal member 4203. At this time, the third connecting head 423 and the fourth connecting head 424 are respectively disposed at two ends of the longitudinal shaft 4203, the first connecting head 421 is disposed at one end of the first transverse shaft 4201 away from the longitudinal shaft 4203, and the second connecting head 422 is disposed at one end of the second transverse shaft 4202 away from the longitudinal shaft 4203. In a specific assembly, the first transverse shaft 4201 is rotatably connected to the first connecting lug 304, the second transverse shaft 4202 is rotatably connected to the second connecting lug 305, and two ends of the longitudinal shaft 4203 are rotatably connected to the first ankle connecting lug 411 and the second ankle connecting lug 412 of the first connecting seat 401, respectively.

As shown in fig. 6 and 7, the ankle connection member 420 also includes a securing bolt 4204, and the longitudinal member 4203 is provided with a bore 42031 having a bore axis perpendicular to the axis of the longitudinal member 4203. In a specific assembly, the first transverse shaft 4201 and the second transverse shaft 4202 respectively correspond to two side hole ports of the through hole 42031, and the fixing bolt 4204 sequentially passes through the first transverse shaft 4201 and the through hole 42031 to be screwed and fixed with the second transverse shaft 4202. In this way, first and second cross members 4201, 4202 are lock fastened to longitudinal member 4203 by fixing bolts 4204.

In assembling the ankle connection member 420 in a modular configuration, the longitudinal shaft member 4203 is first placed between the first ankle connection ear 411 and the second ankle connection ear 412, then the first transverse shaft member 4201 is placed between the first connection ear 304 and the longitudinal shaft member 4203, and the second transverse shaft member 4202 is placed between the second connection ear 305 and the longitudinal shaft member 4203, and then the first transverse shaft member 4201 and the second transverse shaft member 4202 are locked to the longitudinal shaft member 4203 by the fixing bolts 4204. The first bearing 431, the second bearing 432, the third bearing 433 and the fourth bearing 434 are then assembled in this order, that is: the first bearing 431 is fitted between the first coupling head 421 and the first coupling lug 304, the second bearing 432 is fitted between the second coupling head 422 and the second coupling lug 305, the third bearing 433 is fitted between the second ankle coupling lug 412 and the third coupling head 423, and the fourth bearing 434 is fitted between the first ankle coupling lug 411 and the fourth coupling head 424.

Additionally, in another embodiment of the present application, ankle connecting member 420 is an integrally formed member. Preferably, the ankle connecting member 420 is an integrally forged member, or the ankle connecting member 420 is a cast member.

The foregoing description of the preferred embodiments of the present application is not intended to be limiting, but is intended to cover any and all modifications, equivalents, and alternatives falling within the spirit and principles of the present application.

Claims (10)

1. A hip joint structure of a biped robot, comprising:

the hip joint structure (110), the hip joint structure (110) comprises a first joint part (111) and a second joint part (112) which are fixedly connected with each other, and the second joint part (112) is used for connecting leg structures of the bipedal robot;

the first driving mechanism (130), the first driving mechanism (130) is fixedly arranged on the second switching part (112), and the first driving mechanism (130) is used for driving the leg structure to swing sideways;

the axis direction of the output rotating shaft of the second driving mechanism (140) is orthogonal to the axis direction of the output rotating shaft of the first driving mechanism (130), the second driving mechanism (140) is used for driving the leg structure to rotate around the axis of the output rotating shaft of the second driving mechanism (140), and the second driving mechanism (140) is mounted on the second switching part (112).

2. The hip joint structure of a bipedal robot of claim 1, wherein the hip joint structure comprises a plurality of support members,

the first switching part (111) and the second switching part (112) are plate-shaped members, the extending direction of the first switching part (111) and the extending direction of the second switching part (112) are orthogonally arranged, and the extending direction of the first switching part (111) is basically horizontal;

the first driving mechanism (130) and the second driving mechanism (140) are respectively located at two sides of the second switching part (112), the second switching part (112) is provided with an assembly hole (1121), and an output rotating shaft of the first driving mechanism (130) passes through the assembly hole (1121) and is connected with the second driving mechanism (140).

3. The hip joint structure of a bipedal robot of claim 2, wherein the hip joint structure comprises a plurality of support members,

the hip joint structure further comprises a hip flange member (151) and a hip support member (152), wherein the hip flange member (151) is fixedly connected to an output rotating shaft of the first driving mechanism (130), the hip support member (152) is fixedly connected to the hip flange member (151), and the second driving mechanism (140) is mounted on the hip support member (152).

4. A hip joint structure of a bipedal robot as claimed in any one of claims 1 to 3,

The hip joint structure further comprises a third driving mechanism (160) and a leg adapting member (170), the leg adapting member (170) is fixedly connected to an output rotating shaft of the second driving mechanism (140), the third driving mechanism (160) is mounted on the leg adapting member (170), both an axial direction of the output rotating shaft of the third driving mechanism (160) and an axial direction of the output rotating shaft of the first driving mechanism (130) and an axial direction of the output rotating shaft of the third driving mechanism (160) and an axial direction of the second driving mechanism (140) are orthogonally arranged, and the leg structure is fixedly connected to the output rotating shaft of the third driving mechanism (160).

5. The hip joint structure of the bipedal robot of claim 4, wherein the hip joint structure comprises a plurality of the legs,

the third drive mechanism (160) is located outside of the leg switching member (170).

6. A biped robot, comprising:

a leg structure; and

a bipedal robot hip as claimed in any one of claims 1 to 5, the leg structure and the hip structure being connected.

7. The bipedal robot of claim 6, wherein the leg structure comprises:

-a thigh limb (210), a first end of the thigh limb (210) being connected to the hip joint structure;

a lower leg portion (300), wherein the lower leg portion (300) is rotatably mounted on the second end of the thigh limb (210), and a first connecting end (311) is arranged at the end of the lower leg portion (300) close to the thigh limb (210);

a knee drive mechanism (220), the knee drive mechanism (220) fixedly mounted to an end of the thigh limb (210) proximate the hip joint structure;

a first knee link (230), the output shaft of the knee drive mechanism (220) is drivingly connected to a first end of the first knee link (230), and a second end of the first knee link (230) is rotatably connected to the first connecting end (311).

8. The bipedal robot of claim 7, wherein the robot is configured to,

the leg structure further comprises a sole part (400), wherein the sole part (400) is provided with a first connecting seat (401) and a second connecting seat (402) which are spaced;

the lower leg portion (300) includes:

a lower leg limb (310), wherein a first end of the lower leg limb (310) is rotatably mounted at a second end of the thigh limb (210), the second end of the lower leg limb (310) is movably connected with the first connecting seat (401), and the second end of the lower leg limb (310) is provided with the first connecting end (311) in an extending manner;

A first calf drive mechanism (320), the first calf drive mechanism (320) being mounted to the calf limb (310);

the output rotating shaft of the first calf driving mechanism (320) is in driving connection with the first end of the first calf connecting rod (330), and the second end of the first calf connecting rod (330) is in rotating connection with the second connecting seat (402).

9. The bipedal robot of claim 8, wherein the robot is configured to,

the lower leg part (300) further comprises a second lower leg driving mechanism (340) and a second lower leg connecting rod (350), the second lower leg driving mechanism (340) is installed on the lower leg limb (310), an output rotating shaft of the second lower leg driving mechanism (340) is in driving connection with a first end of the second lower leg connecting rod (350), a second end of the second lower leg connecting rod (350) is in rotating connection with the second connecting seat (402), and the first lower leg connecting rod (330) and the second lower leg connecting rod (350) are arranged in parallel.

10. The bipedal robot of claim 8 or 9, wherein the robot further comprises a gripper,

the leg structure further comprises an ankle connecting member (420), the ankle connecting member (420) is provided with a first connecting head (421), a second connecting head (422), a third connecting head (423) and a fourth connecting head (424), the connecting line of the first connecting head (421) and the second connecting head (422) is perpendicular to the connecting line of the third connecting head (423) and the fourth connecting head (424), the second end of the shank (310) is provided with a first connecting lug (304) and a second connecting lug (305) which are opposite and are spaced, the first connecting seat (401) comprises a first ankle connecting lug (411) and a second ankle connecting lug (412) which are opposite and spaced, the connecting line of the first ankle connecting lug (411) and the second ankle connecting lug (412) is perpendicular to the connecting line of the first connecting lug (304) and the second connecting lug (305), the first connecting head (421) is rotationally connected to the first connecting lug (304), the second connecting head (422) is rotationally connected to the second ankle connecting lug (424), and the first ankle connecting lug (411) is rotationally connected to the second ankle connecting lug (412).

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