Humanoid robot leg structure

Abstract

The invention relates to a humanoid robot leg structure which comprises thighs, knee joints, shanks, ankle joints and shanks. The thigh part comprises a first joint module motor and a second joint module motor; the knee joint comprises a first pull rod, a second pull rod and a connecting seat; the first joint module motor is connected with the connecting seat through the first pull rod; the shank part comprises a shank pull rod and a third joint module motor; the second joint module motor is connected with the foot through a second pull rod and a shank pull rod; the third joint module motor is connected with the foot through a shank pull rod; the foot part comprises a front support and a rear support which are connected through a foot support rotating shaft. Compared with the prior art, the humanoid robot has the advantages that the second joint module motor and the third joint module motor are located on the thigh portion and the shank portion respectively, symmetrical arrangement is not needed, module motors with larger size and torque can be arranged, and the motion ability of the humanoid robot is enhanced; the foot part comprises a front support and a rear support, and can adapt to different terrains.

Description

Technical Field

[0001] The invention relates to a robot, in particular to a leg structure of a humanoid robot. Background Art

[0002] With the rapid development of robotics technology, humanoid robots have broad application prospects in the fields of service, medical rehabilitation, and human-computer interaction. Their design imitates human walking and operation, so joint design is crucial, especially the ankle joints of the lower limbs, which determine the robot's performance in walking, balancing, and adapting to complex terrain.

[0003] At present, most of the leg structure designs of single-legged six-degree-of-freedom humanoid robots mainly place two drive modules on the top of the calf in the ankle joint design, and realize the two-degree-of-freedom control of the ankle joint through a connecting rod; or place them on the ankle joint through a direct connection. However, the current common leg structure scheme concentrates both drive modules below the knee joint, which has high requirements on the calf structure space and the volume of the drive module, limiting the expression of the leg appearance design. In addition, the narrow space below the knee joint in the existing scheme cannot accommodate large-volume, high-torque joint drive modules, which limits the driving ability of the ankle joint, thereby limiting the overall humanoid robot's movement ability and the completion of posture movements, and also increases the leg dynamics burden during the humanoid robot's walking movements.

[0004] After searching, the application publication number CN116573077A discloses a biped robot lower limb structure with passive compliant calves, which specifically discloses: a pelvis and a left leg and a right leg arranged on both sides of the pelvis; the left leg and the right leg have the same structure, both including a hip joint mechanism, a thigh mechanism, a knee joint mechanism, a calf mechanism, an ankle joint mechanism and a sole, wherein the hip joint mechanism is rotatably connected to the upper end of the thigh mechanism, the hip joint mechanism is used to drive the thigh mechanism to perform yaw, roll and pitch movements, the lower end of the thigh mechanism is rotatably connected to the upper end of the calf mechanism through the knee joint mechanism, the knee joint mechanism is used to drive the calf mechanism to perform pitch movements; the lower end of the calf mechanism is connected to the sole of the foot through the ankle joint mechanism, and the ankle joint mechanism is used to drive the sole of the foot to perform pitch and roll movements. However, the adaptability of the sole of the prior art in complex environments is poor.

[0005] In summary, how to design a humanoid robot leg structure with strong movement ability and strong adaptability to complex environments is a technical problem that needs to be solved. Summary of the invention

[0006] The purpose of the present invention is to overcome the defects of the above-mentioned prior art such as poor movement ability or poor adaptability in complex environments and to provide a humanoid robot leg structure with improved ankle joint control ability and in accordance with the principle of dynamic control, aiming to reduce movement inertia and improve overall performance.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] According to one aspect of the present invention, there is provided a humanoid robot leg structure, comprising a thigh, a knee joint, a calf, an ankle joint and a foot connected in sequence;

[0009] The thigh part includes a motor mounting block, a connecting plate, a first joint module motor and a second joint module motor, wherein the first joint module motor is mounted between the motor mounting block and the connecting plate, and the second joint module motor is mounted on the connecting plate; the axes of the first joint module motor and the second joint module motor are parallel;

[0010] The knee joint comprises a first pull rod, a second pull rod and a connecting seat, and the first joint module motor is connected to the connecting seat via the first pull rod;

[0011] The calf part includes a calf plate, a first calf pull rod, a second calf pull rod and a third joint module motor, wherein the third joint module motor is mounted on the calf plate; the second joint module motor is connected to one side of the foot through the second pull rod and the second calf pull rod; the third joint module motor is connected to the other side of the foot through the first calf pull rod; the axes of the third joint module motor and the second joint module motor are skewed and perpendicular;

[0012] The foot portion comprises a foot support shaft and a front support and a rear support connected via the foot support shaft, and the rear support is connected to the calf plate via an ankle joint.

[0013] As a preferred technical solution, the thigh part also includes a first cam, a positioning pin shaft and a second cam, and the positioning pin shaft is installed between the motor mounting block and the connecting plate; the first joint module is connected to the first cam, one end of the first pull rod is connected to the first cam, and the other end is connected to the connecting seat; the second joint module motor is connected to the second cam, one end of the second pull rod is connected to the second cam through a ball joint, and the other end is connected to one side of the foot.

[0014] As a preferred technical solution, the knee joint also includes a first connecting rod, an auxiliary connecting rod, a first knee joint pivot, a first pin, a second knee joint pivot and a third knee joint pivot; the first knee joint pivot connects one end of the first connecting rod and a connecting seat, the first pin connects the other end of the first connecting rod and one end of the auxiliary connecting rod, and the third knee joint pivot is installed on the other end of the auxiliary connecting rod; the second knee joint pivot is installed in the connecting seat, and both ends are respectively installed on the motor mounting plate and the connecting plate; the first pull rod is connected to the first pin.

[0015] As a preferred technical solution, the knee joint further includes a fourth cam, the fourth cam is fixed to the end face of the second knee joint shaft, and one end of the second pull rod is connected to the fourth cam.

[0016] As a preferred technical solution, the calf part also includes an ankle joint shaft, a third cam, a transition block, a second connecting rod, a first pull rod ball joint and a second pull rod ball joint; the calf plate is connected to the ankle joint through the ankle joint shaft; the third cam is installed at the output end of the third joint module motor, and the third cam is provided with an extension shaft, and a rotating pair is formed between the extension shaft and the transition block; the first calf pull rod is connected to the third cam through the first pull rod ball joint; one end of the second connecting rod is connected to the fourth cam through a ball joint, and the other end is connected to the connecting block; the second calf pull rod is connected to the transition block through the second pull rod ball joint.

[0017] As a preferred technical solution, the ankle joint includes a copper sleeve and a cross shaft; a first through hole and a second through hole perpendicular to each other are provided in the cross shaft, and the copper sleeve passes through the first through hole to form a revolving pair with the cross shaft; the calf also includes an ankle joint revolving shaft, and the ankle joint revolving shaft passes through the second through hole to form a revolving pair with the cross shaft.

[0018] As a preferred technical solution, the foot also includes two flange shafts, and both ends of the two flange shafts are respectively provided with an extended first mounting shaft and a second mounting shaft, the first mounting shafts of the two flange shafts are installed on both sides of the rear support, and the second mounting shafts of the two flange shafts are respectively connected to the first calf pull rod and the second calf pull rod.

[0019] As a preferred technical solution, the foot also includes a second pin, a double-sided torsion spring and a buffer block; the second pin passes through the ankle joint to form a revolving pair with the ankle joint; a buffer block is installed in the middle of the foot support shaft, and double-sided torsion springs are mounted on both ends.

[0020] As a preferred technical solution, pads are installed on the sides of the front support and the rear support close to the ground.

[0021] As a preferred technical solution, the calf plate is provided with weight-reducing holes and oblique supports.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1) The first joint module motor of the present invention is located in the thigh to drive the knee joint; the second joint module motor and the third joint module motor are respectively located in the thigh and the calf to drive the ankle joint, and do not need to be symmetrically arranged. Under the condition of reducing the inertia of the leg movement, the requirements for the external dimensions of the module motor are reduced, and a module motor with a larger volume and torque can be arranged to enhance the movement ability of the humanoid robot; the foot includes a front support and a rear support connected by a foot support shaft, which can adapt to different terrains;

[0024] 2) The second joint module motor and the third joint module motor of the present invention drive the foot to move through the transmission chain. When the first tie rod ball joint and the second tie rod ball joint are at the same height, pitch motion is achieved; when the first tie rod ball joint and the second tie rod ball joint are not at the same height, the foot rotates around the second pin shaft to achieve rolling motion; decoupling control of the ankle joint is achieved;

[0025] 3) The elastic force of the bilateral torsion spring of the present invention maintains the fitting state of the front support and the rear support, so that the bottom surface of the foot can adapt to the changes of different terrains; in addition, the pads installed on the bottom of the foot can effectively reduce the impact of the ground on the robot's feet, provide shock absorption and buffering effects, and enhance the robot's adaptability in complex environments;

[0026] 4) The calf board of the present invention is provided with weight-reducing holes, which helps to improve the flexibility and endurance of the robot, and the oblique support design is adopted to ensure the structural strength of the calf board. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a front view of the leg structure of a humanoid robot according to the present invention;

[0028] Figure 2 This is a schematic diagram of the overall structure of a humanoid robot leg structure of the present invention;

[0029] Figure 3 It is a schematic diagram of the structure of the knee joint, calf, ankle joint and foot of the present invention;

[0030] Figure 4 An exploded view of the thigh and knee joint structure of the present invention;

[0031] Figure 5 An exploded view of the ankle joint structure of the present invention;

[0032] Figure 6 This is an exploded view of the foot structure of the present invention;

[0033] The numbers in the figure show:

[0034] 100, thigh, 101, connecting assembly, 102, first joint module motor, 103, first cam, 104, motor mounting block, 105, positioning pin, 107, second cam, 108, second joint module motor, 109, connecting plate, 200, knee joint, 201, first pull rod, 202, cover plate, 203, radial joint bearing, 204, first retaining spring, 205, auxiliary connecting rod, 206, first connecting rod, 207, connecting seat, 208, first knee joint shaft, 209, first pin, 210, second knee joint shaft, 211, third knee joint shaft, 212, first bearing, 213, second retaining spring, 214, second bearing, 215, gasket, 216, third retaining spring, 217 , fourth cam, 218, second pull rod, 219, anti-interference groove, 300, calf, 301, third joint module motor, 302, calf plate, 303, ankle joint shaft, 3041, first calf pull rod, 3042, second calf pull rod, 305, third cam, 306, transition block, 307, second connecting rod, 3081, first pull rod ball joint, 3082, second pull rod ball joint, 400, ankle joint, 401, copper sleeve, 402, cross shaft, 403, third bearing, 500, foot, 501, second pin shaft, 502, buffer block, 503, double-sided torsion spring, 504, front support, 505, foot support shaft, 506, pad, 507, rear support, 508, flange shaft, 509, set screw. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0036] like Figure 1 As shown, the present invention provides a humanoid robot leg structure, including a thigh part 100, a knee joint 200, a calf part 300, an ankle joint 400 and a foot 500.

[0037] like Figure 2 and Figure 3 As shown, the thigh part 100 includes a connection component 101, a first joint module motor 102, a first cam 103, a motor mounting block 104, a positioning pin 105, a second cam 107, a second joint module motor 108 and a connection plate 109. The connection component 101 is used to connect with the hip joint of the humanoid robot.

[0038] The connecting plate 109 and the motor mounting block 104 are respectively installed on both sides of the connecting assembly 101, and are positioned with the extended shaft of the connecting assembly 101 through the pin hole, and connected with the bolt and the threaded hole. The connecting plate 109 is connected to the motor mounting block 104 through the connecting assembly 101. The axis of the bottom hole of the motor mounting block 104 and the connecting plate 109 coincide, and the first bearing 212 is installed in each hole, fixed by the second retaining spring 213, and forms a revolute pair with the knee joint 200. The connecting plate 109 is provided with an anti-interference groove 219 to prevent interference with the knee joint 200 when the leg is bent.

[0039] The first joint module motor 102 and the second joint module motor 108 respectively control the movement of the knee joint 200 and the ankle joint 400. The first joint module motor 102 is mounted on the motor mounting block 104 by bolts, and its output end is connected to the first cam 103 by a flat head screw, and the bolts on the end face of the first cam 103 are connected to the upper end of the first pull rod 201, and the holes at both ends of the first pull rod 201 are installed with the radial spherical bearing 203, which is fixed by the first retaining spring 204, and the first retaining spring 204 is an earless retaining spring, and the inner ring of the radial spherical bearing 203 cooperates with the second knee joint shaft 210 to realize the pitching movement of the knee joint 200, ensuring the stability of the spatial movement during the transmission process.

[0040] The axes of the second joint module motor 108 and the first joint module motor 102 are skewed and perpendicular. The second joint module motor 108 is installed in the middle of the thigh, passes through the motor mounting block 104 and is fixed to the connecting plate 109 by bolts. The output end thereof is connected to the second pull rod 218 through the second cam 107, thereby realizing the movement of the ankle joint 400.

[0041] like Figure 3 and Figure 4 As shown, the knee joint 200 includes a first pull rod 201, a cover plate 202, a radial spherical bearing 203, a first retaining spring 204, an auxiliary connecting rod 205, a first connecting rod 206, a connecting seat 207, a first knee joint pivot 208, a first pin 209, a second knee joint pivot 210, a third knee joint pivot 211, a first bearing 212, a second retaining spring 213, a second bearing 214, a gasket 215, a third retaining spring 216, a fourth cam 217 and a second pull rod 218.

[0042] The double rocker structure of the knee joint 200 uses an auxiliary link 205 and a first link 206. One end of the first tie rod 201 is connected to the first cam 103 through a ball joint and a bolt, and the other end is connected to the first link 206 and the auxiliary link 205 in sequence through a first pin 209, and fixed by a nut, so as to achieve stable pitching motion of the knee joint 200 while maintaining lightness and flexibility during motion.

[0043] There are mounting holes on both sides of the second pull rod 218, and the middle section is arc-shaped. There are three mounting holes on the fourth cam 217. The upper end of the second pull rod 218 is connected to the second cam 107 through a ball joint, and the lower end is connected to the front mounting hole of the fourth cam 217. The middle hole of the fourth cam 217 is connected to the second bearing 214 and the third retaining spring 216. A gasket 215 is installed on the outer side of the inner ring of the bearing and is fixed to the threaded hole on the end face of the second knee joint shaft 210 by screws. Therefore, the axis of the inner hole of the fourth cam 217 coincides with the axis of the second knee joint shaft 210, and the rear hole of the fourth cam 217 is connected to one end of the second connecting rod 307 through a ball joint. The axes of the upper and lower end holes of the second connecting rod 307 are skewed and perpendicular, and the hole at the lower end is connected to the transition block 306 through a ball joint.

[0044] The first knee joint shaft 208 connects the single head end of the first connecting rod 206 and the connecting seat 207, and is inserted into and positioned in the groove of the first knee joint shaft 208 through the fixing screw 509 from the connecting seat 207. There is a threaded hole in the groove in the middle of the connecting seat 207, and the second knee joint shaft 210 is fixed in the groove by screws.

[0045] Both ends of the second knee joint shaft 210 cooperate with the thigh 100 through the first bearing 212, and are respectively installed in the holes below the connecting plate 109 and the motor mounting block 104, and are driven by the first joint module motor 102 to drive the second knee joint shaft 210 to rotate around the thigh 100.

[0046] The third knee joint shaft 211 passes through the other end of the auxiliary connecting rod 205 and is fixed by screws through the cover plate 202 outside the motor mounting block 104 .

[0047] like Figure 3 As shown, the calf part 300 is connected to the thigh part 100 through the knee joint 200. The calf part 300 includes a third joint module motor 301, a calf plate 302, an ankle joint shaft 303, a calf pull rod, a third cam 305, a transition block 306, a second connecting rod 307 and a pull rod ball joint. The calf pull rod includes a first calf pull rod 3041 and a second calf pull rod 3042; the pull rod ball joint includes a first pull rod ball joint 3081 and a second pull rod ball joint 3082.

[0048] The third joint module motor 301 is installed on the calf plate 302 to control the pitching motion of the ankle joint 400. The threaded hole on the upper side of the calf plate 302 is fixed to the connecting plate 109 by screws, and there is a mounting hole on the lower side. The third joint module motor 301 is fixed in the calf plate 302 by screws. The third cam 305 is installed at the output end of the third joint module motor 301 by screws, and is located at the rear side of the calf part 300. The outer side of the third cam 305 is provided with an extension shaft, which is connected to the hole position with a projection of the transition block 306 to form a rotary pair. The left side of the third cam 305 is connected to the upper end hole of the first calf pull rod 3041 by bolts and ball joints, and the lower right side hole of the transition block 306 is connected to the upper end hole of the second calf pull rod 3042 by bolts and ball joints. When the first tie rod ball joint 3081 and the second tie rod ball joint 3082 are at the same height, the foot 500 can achieve pitch motion; when the first tie rod ball joint 3081 and the second tie rod ball joint 3082 are not at the same height, the foot 500 rotates around the second pin 501 to achieve rolling motion. The control system feeds back the actual position of the sole of the foot through the sensor and adjusts the movement of the motor in real time. The rotation angle of each motor is automatically adjusted according to the expected posture of the sole of the foot, thereby achieving precise movement of two-legged walking and posture control. Through the design of the decoupled ankle joint 400, the robot can flexibly complete actions such as squatting, walking, and single-leg support, thereby enhancing the ability to walk in complex terrain. The calf plate 302 is made of lightweight and high-strength materials, such as magnesium-aluminum alloy. Holes are dug in the middle of the calf plate 302 to reduce weight and achieve lightweight design. At the same time, the oblique support design is adopted to ensure its structural strength, further improving the flexibility and endurance of the robot. The fork with threaded holes on the lower side is used to fix the cross shaft 402.

[0049] like Figure 5 As shown, the ankle joint 400 adopts a cross shaft 402 structure, including a copper sleeve 401, a cross shaft 402 and a third bearing 403. There are two mutually perpendicular through holes in the cross shaft 402, which are connected to the second knee joint shaft 210 through the third bearing 403 to form a revolute pair with a certain angle limit. The through hole of the copper sleeve 401 and the cross shaft 402 constitute a revolute pair, and the second pin 501 passes through the cross shaft 402 and the copper sleeve 401 and is installed on the oblique hole above the back support 507 through a set screw 509 to form a revolute pair of the ankle joint 400. The second joint module motor 108 and the third joint module motor 301 drive the foot 500 to perform pitch and roll motions through a transmission chain to achieve decoupling control of the ankle joint 400.

[0050] like Figure 6As shown, the foot 500 includes a second pin 501, a buffer block 502, a bilateral torsion spring 503, a front support 504, a foot support shaft 505, a cushion block 506, a rear support 507, a flange shaft 508 and a set screw 509. The foot support shaft 505 is installed on the front side of the rear support 507 through the set screw 509, and the front support 504 and the rear support 507 are connected through the foot support shaft 505 to form an adjustable support structure. The flange shaft 508 is installed in the circular contour groove on the rear side of the rear support 507, and has extended mounting shafts at both ends. One end of the extended shaft is installed in the slot hole at the rear of the rear support 507, and the other end of the extended shaft is threaded. The first calf pull rod 3041 and the second calf pull rod 3042 are connected to the flange shafts 508 on both sides through ball joints and nuts respectively. A buffer block 502 is connected in the middle of the foot support shaft 505, and two-sided torsion springs 503 are connected at both ends. When no external force is applied, the elastic force of the two-sided torsion springs 503 keeps the inclined protrusions of the front support 504 and the rear support 507 in contact, so that the bottom surface is on the same plane. The two can rotate at a certain angle through the connected foot support shaft 505, so that the bottom surface of the foot 500 can adapt to the changes in different terrains. In addition, a pad 506 is installed on the side of the front support 504 and the rear support 507 close to the ground. The pad 506 can be made of rubber material, which can effectively reduce the impact of the ground on the robot foot 500, provide shock absorption and buffering, and enhance the robot's adaptability in complex environments. The second joint module motor 108 and the third joint module motor 301 are controlled to drive the rotation of the foot 500 in space through the transmission chain; the expected posture of the sole is reflected to the rotation position of each motor, thereby controlling the movement of the legs, so that the robot legs can achieve squatting, walking and other actions.

[0051] The present invention controls the pitch motion of the knee joint 200 through the first joint module motor 102, and the second joint module motor 108 and the third joint module motor 301 respectively control the pitch and roll motion of the foot 500 through the transmission chain; the coordinated control of the first joint module motor 102, the second joint module motor 108 and the third joint module motor 301 realizes the precise control of the pitch motion of the knee joint 200, the roll motion of the ankle joint 400 and the pitch motion of the foot 500. When the present invention is applied to a humanoid robot, the two legs are arranged symmetrically, and the robot adopting the leg structure of the present invention can realize high-degree-of-freedom motion, especially the stability and flexibility in complex terrain are significantly improved. The decoupling design of the ankle joint 400 avoids the influence of motion coupling on posture control, making the control system simpler and more efficient, and suitable for application in a variety of scenarios, including service industries, medical rehabilitation and complex terrain tasks.

[0052] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A humanoid robot leg structure, characterized in that: It comprises a thigh part (100), a knee joint (200), a calf part (300), an ankle joint (400) and a foot part (500) which are connected in sequence; The thigh part (100) comprises a motor mounting block (104), a connecting plate (109), a first joint module motor (102) and a second joint module motor (108); the first joint module motor (102) is mounted between the motor mounting block (104) and the connecting plate (109), and the second joint module motor (108) is mounted on the connecting plate (109); the axes of the first joint module motor (102) and the second joint module motor (108) are parallel; The knee joint (200) comprises a first pull rod (201), a second pull rod (218) and a connecting seat (207); the first joint module motor (102) is connected to the connecting seat (207) via the first pull rod (201); The calf part (300) comprises a calf plate (302), a first calf pull rod (3041), a second calf pull rod (3042) and a third joint module motor (301), wherein the third joint module motor (301) is mounted on the calf plate (302); the second joint module motor (108) is connected to one side of the foot (500) via a second pull rod (218) and a second calf pull rod (3042); the third joint module motor (301) is connected to the other side of the foot (500) via the first calf pull rod (3041); the axes of the third joint module motor (301) and the second joint module motor (108) are not in the same plane and are perpendicular; The foot (500) includes a foot support shaft (505) and a front support (504) and a rear support (507) connected via the foot support shaft (505); the rear support (507) is connected to the calf plate (302) via an ankle joint (400).

2. A humanoid robot leg structure according to claim 1, characterized in that: The thigh part (100) also includes a first cam (103), a positioning pin shaft (105) and a second cam (107), wherein the positioning pin shaft (105) is installed between the motor mounting block (104) and the connecting plate (109); the first joint module is connected to the first cam (103), one end of the first pull rod (201) is connected to the first cam (103), and the other end is connected to the connecting seat (207); the second joint module motor (108) is connected to the second cam (107), one end of the second pull rod (218) is connected to the second cam (107) through a ball joint, and the other end is connected to one side of the foot (500).

3. The humanoid robot leg structure according to claim 1, characterized in that: The knee joint (200) further includes a first connecting rod (206), an auxiliary connecting rod (205), a first knee joint rotating shaft (208), a first pin (209), a second knee joint rotating shaft (210) and a third knee joint rotating shaft (211); the first knee joint rotating shaft (208) is connected to one end of the first connecting rod (206) and a connecting seat (207), the first pin (209) is connected to the other end of the first connecting rod (206) and one end of the auxiliary connecting rod (205), and the third knee joint rotating shaft (211) is installed on the other end of the auxiliary connecting rod (205); the second knee joint rotating shaft (210) is installed in the connecting seat (207), and the two ends are respectively installed on the motor mounting plate and the connecting plate (109); the first pull rod (201) is connected to the first pin (209).

4. The humanoid robot leg structure according to claim 3, characterized in that: The knee joint (200) further comprises a fourth cam (217), wherein the fourth cam (217) is fixed to the end surface of the second knee joint rotating shaft (210), and one end of the second pull rod (218) is connected to the fourth cam (217).

5. The humanoid robot leg structure according to claim 1, characterized in that: The calf part (300) also includes an ankle joint shaft (303), a third cam (305), a transition block (306), a second connecting rod (307), a first pull rod ball joint (3081) and a second pull rod ball joint (3082); the calf plate (302) is connected to the ankle joint (400) through the ankle joint shaft (303); the third cam (305) is installed at the output end of the third joint module motor (301), and the third cam (305) is provided with an extension shaft, and a rotating pair is formed between the extension shaft and the transition block (306); the first calf pull rod (3041) is connected to the third cam (305) through the first pull rod ball joint (3081); one end of the second connecting rod (307) is connected to the fourth cam (217) through a ball joint, and the other end is connected to the connecting block; the second calf pull rod (3042) is connected to the transition block (306) through the second pull rod ball joint (3082).

6. The humanoid robot leg structure according to claim 1, characterized in that: The ankle joint (400) comprises a copper sleeve (401) and a cross shaft (402); a first through hole and a second through hole perpendicular to each other are arranged in the cross shaft (402); the copper sleeve (401) passes through the first through hole to form a rotation pair with the cross shaft (402); the calf part (300) further comprises an ankle joint rotation shaft (303); the ankle joint rotation shaft (303) passes through the second through hole to form a rotation pair with the cross shaft (402).

7. The humanoid robot leg structure according to claim 1, characterized in that: The foot (500) also includes two flange shafts (508), and the two ends of the two flange shafts (508) are respectively provided with an extended first mounting shaft and a second mounting shaft, the first mounting shafts of the two flange shafts (508) are installed on both sides of the rear support (507), and the second mounting shafts of the two flange shafts (508) are respectively connected to the first calf pull rod (3041) and the second calf pull rod (3042).

8. The humanoid robot leg structure according to claim 1, characterized in that: The foot (500) further comprises a second pin (501), a double-sided torsion spring (503) and a buffer block (502); the second pin (501) passes through the ankle joint (400) and forms a rotation pair with the ankle joint (400); a buffer block (502) is installed in the middle of the foot support shaft (505), and double-sided torsion springs (503) are sleeved at both ends.

9. The humanoid robot leg structure according to claim 1, characterized in that: A cushion block (506) is installed on one side of the front support (504) and the rear support (507) close to the ground.

10. The humanoid robot leg structure according to claim 1, characterized in that: The calf plate (302) is provided with a weight-reducing hole and an oblique support.

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