Knee joint mechanism of bionic humanoid robot, robot and method

Abstract

The invention discloses a bionic humanoid robot knee joint mechanism, a robot and a method, solves the problems that in the prior art, a humanoid robot is difficult to squat and stand up after squatting, and has the beneficial effect that the humanoid robot is convenient to smoothly stand up from squatting down. Comprising a first power source, the first power source is arranged at the end, away from a shank part, of a thigh part and connected with the middle section of a rocker, the two ends of the rocker are connected with one end of a first connecting rod and one end of a second connecting rod respectively, and the other end of the first connecting rod is connected with a third connecting rod shaft; the third connecting rod is rotationally connected with the third connecting rod shaft and the shank part, the fourth connecting rod is rotationally connected with the third connecting rod shaft and the knee joint shaft, the fifth connecting rod is rotationally connected with the second connecting rod and the knee joint shaft, and the short side end of the fifth connecting rod is rotationally connected with the shank part.

Description

Technical Field

[0001] The present invention relates to the field of robot technology, and in particular to a bionic humanoid robot knee joint mechanism, a robot and a method. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Humanoid robots not only simulate human appearance, but also simulate human behavior. People can stand up from squatting, especially from deep squatting to upright position. This is because when people squat, the contact point between the thigh bone and the shin bone is far back, and the tendon connecting the quadriceps femoris is far away from the contact point, and the force arm is large, which is conducive to people standing up from a squatting state. It is difficult for existing robots to achieve this goal. The reasons are: Existing humanoid robots usually place the knee joint drive motor directly at the knee joint. The robot knee joint only requires a large joint drive torque in the initial stage of standing up from a squatting state, and requires a smaller drive torque in other stages. This motor arrangement requires the motor to have a large peak torque, which makes the mass at the knee joint larger and reduces the dynamic characteristics of the robot. Some humanoid robots move the knee joint drive motor up to the base of the thigh and drive the knee joint movement through a set of four-bar linkage mechanisms. This arrangement cannot enable the robot to have a large knee joint motion range close to that of humans. At the same time, after the robot squats, due to the small distance between the connecting rod and the axis of the knee joint, that is, the lever arm, the robot has difficulty standing up or cannot perform a deep squat at all.

[0004] In addition, the foot movement of the humanoid robot is driven by a motor installed at the ankle, which makes the mass of the ankle large, which is not conducive to the smooth movement of the robot's legs. Or it is driven by two sets of linear drives installed at the legs. Because the movement of the two sets of linear drives is seriously coupled, during the movement of the foot, the two sets of linear drives need to be controlled simultaneously to meet the movement requirements of the foot. This process requires complex motion solution, which makes the control more difficult. Summary of the invention

[0005] In view of the deficiencies in the prior art, an object of the present invention is to provide a bionic humanoid robot knee joint mechanism, so that the humanoid robot can squat and turn from a squatting state to an upright state.

[0006] In order to achieve the above object, the present invention is implemented through the following technical solutions: A knee joint mechanism of a bionic humanoid robot, comprising a first power source, which is arranged at one end of the thigh away from the calf. The first power source is connected to the middle section of a rocker. The two ends of the rocker are respectively connected to one end of a first connecting rod and one end of a second connecting rod. The other end of the first connecting rod is connected to a third connecting rod shaft. One end of the thigh close to the calf supports a knee joint shaft. The third connecting rod is respectively rotatably connected to the third connecting rod shaft and the calf. A fourth connecting rod is respectively rotatably connected to the third connecting rod shaft and the knee joint shaft. A fifth connecting rod is rotatably connected to the second connecting rod and rotatably connected to the knee joint shaft. The short side end of the fifth connecting rod is rotatably connected to the calf. When the first power source operates, it drives the third connecting rod shaft to rotate around the knee joint shaft through the first connecting rod, the third connecting rod and the fourth connecting rod, and at the same time drives the calf to move through the second connecting rod, thereby realizing the movement of the calf relative to the thigh.

[0007] For the knee joint mechanism of a bionic humanoid robot as described above, the calf supports a calf rotating shaft. The fifth connecting rod is L-shaped. The long side end of the fifth connecting rod is rotatably connected to the second connecting rod through a first connecting rod shaft. The right angle at the middle of the fifth connecting rod is rotatably connected to the knee joint shaft. The other end of the fifth connecting rod is rotatably connected to the calf rotating shaft.

[0008] For the knee joint mechanism of a bionic humanoid robot as described above, an inclined section is arranged on one side of the calf close to the thigh. One side of the inclined section close to the first connecting rod is rotatably connected to the third connecting rod, and the other side of the inclined section supports the calf rotating shaft.

[0009] For the knee joint mechanism of a bionic humanoid robot as described above, the calf supports a second connecting rod shaft. The third connecting rod is rotatably connected to the second connecting rod shaft. When the humanoid robot stands, the third connecting rod shaft is arranged higher than the second connecting rod shaft. The central axis of the second connecting rod shaft is located in front of the central axis of the knee joint shaft. The central axis of the third connecting rod shaft is arranged higher than the central axis of the knee joint shaft. The first connecting rod shaft is located behind the knee joint shaft.

[0010] For the knee joint mechanism of a bionic humanoid robot as described above, during the process of the humanoid robot bending its knees from the upright state, the second connecting rod shaft gradually comes to the rear side of the third connecting rod shaft.

[0011] For the knee joint mechanism of a bionic humanoid robot as described above, the first connecting rod is connected to the middle section of the third connecting rod shaft. The third connecting rod and the fourth connecting rod are sequentially arranged on both sides of the first connecting rod with respect to the third connecting rod shaft.

[0012] A knee joint mechanism of a humanoid robot as described above, wherein the thigh portion includes two side plates, a hollow portion is formed between the two side plates, the first link passes through the hollow portions of the two side plates, and one end of the side plate close to the calf portion is bent outward to form a bent end. The third link shaft and the knee joint shaft are disposed inside the bent ends of the two side plates, and the bent end is arc-shaped; The second link extends beyond the side plates of the thigh portion.

[0013] In a second aspect, the present invention further provides a humanoid robot, including the knee joint mechanism of the humanoid robot as described above. A foot is provided at the bottom of the calf portion, and a second power source is provided on one side of the calf portion close to the thigh portion. The second power source is connected to the foot to drive the movement of the foot.

[0014] In a humanoid robot as described above, the second power source includes two motors. The two motors are respectively connected to corresponding planetary reduction mechanisms through transmission components. The planetary reduction mechanisms are installed on one side of the calf portion close to the foot. The planet carrier of one set of planetary reduction mechanisms extends a longitudinal axis forward and backward to be connected to the foot, driving the foot to perform pitching swing relative to the calf portion. A first bevel gear is provided on the planet carrier of the other set of planetary reduction mechanisms, and the first bevel gear meshes with a second bevel gear fixed on the foot, driving the foot to perform rolling swing relative to the calf portion.

[0015] In a third aspect, the present invention further provides a working method of a humanoid robot, including the following content: The thigh portion, the rocker, the first link and the fourth link form a four-bar linkage mechanism. A part of the fifth link, the third link, the fourth link and the calf portion form a four-bar linkage mechanism. The rocker, the second link, the fifth link and the thigh portion form a four-bar linkage mechanism. When the humanoid robot is in an upright state, when the first power source operates, the third link shaft is pushed to rotate around the knee joint shaft through the first link, the third link and the fourth link. At the same time, the calf portion is driven to move through the second link, thereby realizing the bending of the calf portion relative to the thigh portion and realizing the squatting of the humanoid robot; After the humanoid robot squats down, the first power source moves in the reverse direction, realizing the straightening movement of the calf portion relative to the thigh portion, and the humanoid robot changes from the squatting state to the upright state; The second power source operates to drive the movement of the foot relative to the calf portion.

[0016] The beneficial effects of the present invention described above are as follows: In the present invention, the first power source serves as the driving power source for the knee joint and is disposed at one end of the thigh away from the calf, avoiding the first power source being disposed at the knee joint. This is equivalent to installing the first power source at the hip joint, reducing the moment of inertia of the leg. The thigh, rocker, first link, and fourth link form a four-bar linkage mechanism. A part of the fifth link, the third link, the fourth link, and the calf form a four-bar linkage mechanism. The rocker, the second link, the fifth link, and the thigh form a four-bar linkage mechanism. Thus, multiple sets of coupled link mechanisms are formed at the knee joint. The fifth link connects the knee joint axis and the calf, and the connection between the fifth link and the calf forms the calf rotation axis. When the humanoid robot gradually stands up from a deep squatting posture, the calf rotation axis moves continuously from the back to the front relative to the thigh, which is similar to the state of a human gradually standing up from a squatting posture. The contact point between the thigh bone and the calf bone moves continuously from the back to the front, and the torque at the knee joint gradually decreases, achieving a high imitation of the human squatting and standing up movements. This not only reduces the peak torque of the first power source but also significantly improves the working condition of the first power source.

[0017] 2) In the present invention, the fifth link is set as an L shape. The end of the long side of the fifth link is rotatably connected to the second link, the right angle is rotatably connected to the lower end of the thigh through the knee joint axis, and the end of the short side is rotatably connected to the calf through the calf rotation axis. Thus, during the movement of the second link, the calf rotation axis is driven to rotate around the knee joint axis by the fifth link, which is beneficial to realizing the squatting and standing up movements of the humanoid robot.

[0018] 3) In the present invention, the calf structure is reasonably arranged. The calf is provided with an inclined section, which is beneficial for the arrangement of the second link axis and also beneficial for the knee joint axis to be close to the calf rotation axis. The structure is reasonably arranged and will not interfere with the relative movement between the thigh and the calf.

[0019] 4) In the present invention, the humanoid robot is provided with feet. The second power source is disposed at a position above the calf, avoiding a heavy mass at the ankle of the humanoid robot. The second power source drives the pitching movement and rolling swing of the feet through transmission components and a planetary gear reduction mechanism, realizing small-torque transmission. This not only reduces the moment of inertia of the calf relative to the knee joint but also meets the large driving torque requirement of the ankle joint. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The specification drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0021] Figure 1 is the front view of a knee joint mechanism of a humanoid robot imitating a human according to one or more embodiments of the present invention.

[0022] Figure 2Schematic diagram of the bending of the lower leg in a humanoid robot knee joint mechanism according to one or more embodiments of the present invention.

[0023] Figure 3 Schematic diagram of the enlarged structure at the knee joint in a humanoid robot knee joint mechanism according to one or more embodiments of the present invention.

[0024] Figure 4 is the present invention Figure 1 Schematic diagram at the A-A cross-section in it.

[0025] Figure 5 is the present invention Figure 1 Schematic diagram at the B-B cross-section in it.

[0026] Figure 6 is the present invention Figure 1 Schematic diagram at the C-C cross-section in it.

[0027] Figure 7 Schematic diagram of the enlarged view of the foot of a humanoid robot according to one or more embodiments of the present invention.

[0028] Figure 8 Schematic diagram of a humanoid robot knee joint mechanism in an upright state according to one or more embodiments of the present invention.

[0029] Figure 9 Schematic diagram of a humanoid robot knee joint mechanism when the lower leg is bent according to one or more embodiments of the present invention.

[0030] In the figure: The distances or sizes between each part are exaggerated for showing the positions of each part, and the schematic diagram is only for illustration.

[0031] Wherein: 101. Thigh part, 1011. First side plate, 1012. Second side plate, 102. First end cover, 103. Rocker, 104. First motor, 105. First bearing, 106. First connecting rod, 107. Second connecting rod, 109. Second end cover, 110. First connecting rod shaft, 111. Third connecting rod, 112. Second connecting rod shaft, 113. Fourth connecting rod, 114. Lower leg part, 115. Fifth connecting rod, 116. Side cover, 117. Synchronous belt, 118. Bevel gear seat, 119. Ankle joint cover, 120. Bearing seat, 121. Foot, 122. Inclined section, 123. Arc-shaped block; 201. First wear-resistant gasket, 202. Third connecting rod shaft, 203. Second wear-resistant gasket, 204. Second bearing; 301. Knee joint axis, 302. Third wear-resistant gasket, 303. Calf rotating shaft, 304. Support plate, 305. First synchronous pulley, 306. Second motor, 307. Fifth bearing, 308. Internal gear ring, 309. Fourth bearing, 310. Third bearing, 311. Retaining ring, 312. Second synchronous pulley, 313. First gear shaft, 314. Planet gear shaft, 315. Fifth bearing, 316. Planet gear, 317. First bevel gear, 318. Planet carrier, 319. Bush, 320. Second bevel gear, 321. Second gear shaft, 322. Ear plate. Detailed implementation mode

[0032] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0033] It should be noted that the terms used herein are only for describing specific implementation modes and are not intended to limit the exemplary implementation modes according to the present invention. As used herein, unless the present invention clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "include" and / or "comprise" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof; As introduced in the background art, in the prior art, it is difficult for humanoid robots to squat down and stand up after squatting. To solve the above technical problems, the present invention proposes a knee joint mechanism for a humanoid robot imitating human beings.

[0034] Embodiment 1 In a typical implementation mode of the present invention, refer to Figure 1As shown in the figure, a knee joint mechanism of a humanoid robot includes a first power source. One end of the thigh part 101 far from the calf part 114 is provided with the first power source, and the first power source is connected to the middle section of the rocker 103. Two ends of the rocker 103 are respectively connected to one end of the first connecting rod 106 and one end of the second connecting rod 107. The other end of the first connecting rod 106 is connected to the third connecting rod shaft 202. One end of the thigh part 101 close to the calf part 114 supports the knee joint shaft. The third connecting rod 111 is respectively rotatably connected to the third connecting rod shaft 202 and the calf part 114. The fourth connecting rod 113 is respectively rotatably connected to the third connecting rod shaft 202 and the knee joint shaft 301. The fifth connecting rod 115 is connected to the second connecting rod 107, and the fifth connecting rod 115 is connected to the knee joint shaft and the calf part 114. The thigh part 101, the rocker 103, the first connecting rod 106 and the fourth connecting rod 113 form a four-bar mechanism. A part of the fifth connecting rod 115, the third connecting rod 111, the fourth connecting rod 113 and the calf part 114 form a four-bar mechanism. The rocker 103, the second connecting rod 107, the fifth connecting rod 115 and the thigh part 101 form a four-bar mechanism. When the first power source operates, it drives the calf part 114 to move around the knee joint shaft 301 through the second connecting rod 107 and the fifth connecting rod 115, and at the same time drives the calf part 114 to rotate around the calf rotation shaft 303 through the first connecting rod 106, the third connecting rod 111 and the fourth connecting rod 113, so as to realize the movement of the calf part 114 relative to the thigh part 101.

[0035] In this embodiment, the thigh part 101 includes two side plates, namely the first side plate 1011 and the second side plate 1012 which are fixedly connected. The first side plate 1011 and the second side plate 1012 have the same structure. A hollow part is formed between the two side plates. The first connecting rod 106 passes through the hollow parts of the two side plates. One side of the first side plate 1011 and the second side plate 1012 far from the calf part 114 is arc-shaped, and the arc-shaped side is used to set the first power source. The first power source is the first motor 104, and the output end of the first motor 104 is connected to the middle section of the rocker 103. The rocker 103 is also arranged in the hollow part between the first side plate 1011 and the second side plate 1012. One end of the first side plate 1011 and the second side plate 1012 close to the calf part 114 is bent outward to form a bent end. The third connecting rod shaft 202 and the knee joint shaft 301 are arranged inside the bent ends of the two side plates, and the side part of the bent end is arc-shaped; the second connecting rod 107 extends beyond the side plates of the thigh part 101.

[0036] Specifically, referring to Figure 3 As shown in the figure, an arc-shaped block 123 is arranged on one side of the calf part 114 close to the thigh part 101 to serve as the knee of the humanoid robot. An inclined section 122 is arranged on one side of the calf part 114 close to the thigh part 101. Two U-shaped grooves are symmetrically arranged at one end of the inclined section 122 close to the first connecting rod. The second connecting rod shaft 112 passes through the two U-shaped grooves to rotatably connect the calf part with the two third connecting rods 111, and the two third connecting rods are respectively arranged in the two U-shaped grooves.

[0037] Reference Figure 1 and Figure 4 As shown, the large-diameter end of the second connecting rod shaft 112 is machined with a special-shaped opposite side, which can be strip-shaped. A corresponding special-shaped groove is machined at the joint of the calf portion 114 and the large-diameter end of the second connecting rod shaft 112 to circumferentially fix the second connecting rod shaft 112. The small-diameter end face of the second connecting rod shaft 112 is machined with a thread and axially fixed to the calf portion 114 through a screw.

[0038] Reference Figure 1 As shown, the rocker 103 is installed at the output end of the first motor 104. There are two protruding ends on both sides of the rotation axis of the rocker 103, and the distances between the two protruding ends relative to the rotation axis of the rocker are different. Short shafts are machined on the protruding ends. The upper end of the first connecting rod 106 is rotationally connected to the short shaft of the long end of the rocker 103 through the first bearing 105 and axially fixed through the first end cover 102. Reference Figure 2 As shown, the lower end of the first connecting rod 106 is rotationally connected to the third connecting rod shaft 202 through the first bearing 105. The other ends of the two third connecting rods 111 are rotationally connected to the third connecting rod shaft 202 through the second bearing 204 and are symmetrically arranged on both sides of the first connecting rod 106. The other ends of the two fourth connecting rods 113 are rotationally connected to the third connecting rod shaft 202 through the second bearing 204 and are symmetrically arranged on both sides of the third connecting rod 111.

[0039] Reference Figure 4 As shown, special-shaped grooves are opened at both ends of the third connecting rod shaft 202. The second end cover 109 is machined with corresponding special-shaped protrusions. The second end cover 109 is fixed to both ends of the third connecting rod shaft 202 through screws to axially fix each connecting rod. First wear-resistant gaskets 201 are installed at the mating surfaces of the first connecting rod 106, the third connecting rod 111, and the fourth connecting rod 113 with the second end cover 109. The upper end of the second connecting rod 107 is rotationally connected to the short shaft of the short end of the rocker 103 through the first bearing 105 and axially fixed through the first end cover 102. The lower end of the second connecting rod 107 is connected to the long side end of the fifth connecting rod 115 through the first connecting rod shaft 110. The second connecting rod is rotationally connected to the first connecting rod shaft through the first bearing 105. A second wear-resistant gasket 203 is installed at the mating surface of the second connecting rod 107 and the fifth connecting rod 115.

[0040] Reference Figure 5As shown, the lower end of the thigh part 101 is rotatably connected to the fourth link 113 and the fifth link 115 through the knee joint axis 301. The two ends of the knee joint axis 301 are processed with special-shaped opposite sides, which can be strip-shaped. The joint between the thigh part 101 and the knee joint axis 301 is processed with a corresponding special-shaped groove to circumferentially fix the knee joint axis 301. The two end faces of the knee joint axis 301 are processed with threaded holes and axially fixed to the thigh part 101 through screws. A third wear-resistant gasket 302 is arranged at the contact position between the inner side of the calf part 114 and the fifth link 115.

[0041] Reference Figure 3 As shown, the fifth link 115 is L-shaped. The long side end of the fifth link is rotatably connected to the second link, and the right angle of the fifth link is rotatably connected to the knee joint axis. The short side end of the fifth link 115 is rotatably connected to the calf part 114 through the calf part rotating shaft 303. The two ends of the calf part rotating shaft 303 are processed with special-shaped opposite sides. The corresponding special-shaped grooves are processed at the cooperation positions between the calf part 114 and the support plate 304 and the calf part rotating shaft 303 to circumferentially fix the calf part rotating shaft 303. The two end faces of the calf part rotating shaft 303 are processed with threaded holes and axially fixed to the calf part 114 and the support plate 304 through screws. The support plate 304 and the calf part 114 are rigidly connected with screws.

[0042] It should be noted that the thigh part 101, the rocker 103, the first link 106, the fourth link 113, the third link 111, the fifth link 115, and the calf part 114 form a compound four-link mechanism, which transmits the rotation and torque output by the first motor 104 to the calf part 114, driving the calf part 114 to swing back and forth relative to the thigh part 101. The thigh part 101, the rocker 103, the second link 107, and the fifth link 115 form a four-link mechanism. This four-link mechanism changes the front and rear positions of the rotation axis of the calf part 114 relative to the thigh part 101 during the leg movement process, improving the force transmission performance of the knee joint. When the humanoid robot gradually stands up from the deep squatting posture, the calf part rotating shaft 303 moves from the back to the front relative to the thigh part 101, which is similar to the state of a person gradually standing up from the squatting posture. The contact point between the thigh bone and the calf bone continuously moves from the back to the front, and the torque at the knee joint gradually decreases, realizing a high imitation of the human squatting and standing up movements. This not only reduces the peak torque of the first power source but also significantly improves the working condition of the first power source and ensures a large movement range of the calf part relative to the thigh part.

[0043] Embodiment 2 This embodiment provides a humanoid robot, reference Figure 6 And Figure 7As shown in the figure, it includes a knee joint mechanism of a bionic humanoid robot described in Embodiment 1. A foot 121 is provided at the bottom of the calf 114. The foot 121 can be a flat plate, and the shape of the foot is similar to that of a human foot. A second power source is provided on one side of the calf 114 close to the thigh. The second power source includes two second motors. One of the second motors is connected to the first gear shaft 313 at the ankle through a first transmission component such as a synchronous belt. After planetary reduction, the first bevel gear 317 drives the foot to roll and swing. The other second motor is connected to the second gear shaft 321 at the ankle through a second transmission component such as a synchronous belt. After planetary reduction, it drives the foot to pitch relative to the calf.

[0044] Specifically, two second motors 306 are symmetrically installed inside the calf 114 near the knee joint (the calf is close to the calf rotation shaft). First synchronous pulleys 305 are respectively installed on the output shafts of the two second motors 306. The lower end of the calf 114 is provided with a U-shaped opening. Ear plates 322 are provided on both sides of the U-shaped opening. Coaxial bearing seat holes are machined on the ear plates 322. Two internal gear rings 308 are respectively installed in the bearing seat holes from the inner sides of the ear plates on both sides of the U-shaped opening and are fixedly connected to the calf 114 by screws. Two third bearings 310 are respectively installed in the bearing seat holes of the ear plates on both sides of the U-shaped opening and are respectively in close contact with the end faces of the internal gear rings 308.

[0045] Reference Figure 5 and Figure 6 As shown in the figure, at one side of the ear plate 322, the internal gear ring 308, the planet gear 316, the first gear shaft 313 and the first bevel gear 317 form a planetary reduction mechanism. The first bevel gear 317 is the support frame of the planet gear. The tooth part of the first bevel gear protrudes from the internal gear ring 308. The first gear shaft 313 is installed inside the first bevel gear 317 through two fourth bearings 309 and is axially fixed by a snap ring 311. A bevel gear seat 118 and a bearing seat 120 are fixedly provided on the foot. The second bevel gear is fixedly installed on the bevel gear seat 118. The first bevel gear meshes with the second bevel gear.

[0046] At the other ear plate, the planet carrier 318, the planet gear 316, the second gear shaft 321 and the internal gear ring 308 form a planetary reduction mechanism. The outer side of the right section of the planet carrier 318 is matched with the third bearing 310 and is axially fixed by a snap ring 311. The planet gear 316 is installed on the right section of the planet carrier 318 through a planet gear shaft 314 and a fifth bearing 315. The second gear shaft 321 is installed inside the right section of the planet carrier 318 through two fourth bearings 309 and is axially fixed by a snap ring 311. A bearing seat hole is machined inside the left section of the planet carrier 318. The right extension shaft section of the first bevel gear 317 is installed in the bearing seat hole of the left section of the planet carrier 318 through two fifth bearings 307. The two fifth bearings 307 are separated and positioned by a bushing 319.

[0047] In fact, the first bevel gear 317 and the planet carrier 318 together form a cross shaft. The horizontal shaft is rotatably connected to the ear plate of the lower leg 114 through two third bearings 310, and the vertical shaft is rotatably connected to the front bearing seat 120 and the rear bevel gear seat 118 of the foot 121 through two fifth bearings 307. Second synchronous belt wheels 312 are respectively installed on the outer extended shaft segments of the first gear shaft 313 and the second gear shaft 321, and are enclosed and protected by the ankle cover 119. The first gear shaft is driven to rotate by the second synchronous belt wheel, and then the first bevel gear is driven to rotate. The second bevel gear drives the foot 121 to perform rolling swing.

[0048] It should be noted that the planet carrier 318 has extended shafts protruding in the front and rear directions on the left section. The extended shafts are the vertical shafts. The front vertical shaft is fixed to the foot 121 through the fifth bearing 307 and the bearing seat 120, and the rear vertical shaft is rotatably connected to the second bevel gear 320 through the fifth bearing 307, while the second bevel gear 320 is rigidly fixed to the foot 121 through the bevel gear seat 118.

[0049] In addition, vertical grooves are formed on both sides of the lower leg 114, and one synchronous belt 117 is installed in each of the two grooves to connect the first synchronous belt wheel 305 and the second synchronous belt wheel 312. When the second motor 306 drives the second gear shaft 321 to rotate through the synchronous belt 117, after planetary reduction, the planet carrier 318 drives the foot to perform pitching motion relative to the lower leg. When the second motor 306 drives the first gear shaft 313 to rotate through the synchronous belt 117, after reduction by the planetary mechanism, the first bevel gear drives the second bevel gear 320 to rotate. Due to the setting of the cross shaft, the second bevel gear 320 drives the foot 121 to rotate around the vertical axis, so that the foot 121 performs rolling swing relative to the lower leg 114. By reasonably controlling the motion of the two second motors 306, the pitching and rolling swing of the foot 121 can be flexibly controlled to ensure full contact with the ground and maintain the stability of the humanoid robot. Side covers 116 are respectively arranged on both sides of the lower leg 114.

[0050] A working method of a humanoid robot includes the following contents: The thigh 101, the rocker 103, the first link 106 and the fourth link 113 form a four-bar mechanism. A part of the fifth link 115, the third link 111, the fourth link 113 and the lower leg 114 form a four-bar mechanism. The rocker 103, the second link 107, the fifth link 115 and the thigh 101 form a four-bar mechanism. When the humanoid robot is in an upright state and the first power source operates, the third link shaft 202 is pushed to rotate around the knee joint shaft 301 through the first link 106, the third link 111 and the fourth link 113, and at the same time, the lower leg 114 is driven to move through the second link 107, thereby realizing the bending of the lower leg 114 relative to the thigh 101. Reference Figure 8 、Figure 9 As shown, when the humanoid robot stands, the thigh part 101 and the calf part 114 are on the vertical line, and the knee joint torque is almost zero. During the movement of the humanoid robot, the first motor 104 drives the rocker 103 to rotate, and drives the calf part 114 to rotate relative to the thigh part 101 through the first connecting rod 106 and the second connecting rod 107. During the process of the humanoid robot bending its knees from the standing position, the force application point between the thigh part 101 and the calf part 114 continuously moves backward, which is similar to the contact point between the thigh and the calf moving away from the patella during the process of a person squatting down. The lever arm of the acting force of the first connecting rod 106 relative to the calf part rotating shaft 303 is continuously increased, always maintaining good force transmission characteristics at the knee joint, and significantly reducing the peak torque of the first motor 104; When a person squats deeply, the contact point is at the back, and the patella is relatively far from the contact point. As the person gradually stands up, the contact point continuously approaches the patella, which is beneficial for the person to stand. When the humanoid robot stands up from the squatting state, the calf part rotating shaft 303 continuously moves from the back to the front relative to the thigh part 101, which is similar to the state of a person gradually standing up from the squatting posture. The contact point between the thigh bone and the calf bone continuously moves from the back to the front, and the torque at the knee joint gradually decreases, achieving a high imitation of the human squatting and standing up movements. It not only reduces the peak torque of the first power source, but also significantly improves the working condition of the first power source.

[0051] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A knee joint mechanism of a humanoid robot, characterized in that, It includes a first power source which is arranged at one end of the thigh away from the calf. The first power source is connected to the middle section of the rocker. Both ends of the rocker are respectively connected to one end of the first connecting rod and one end of the second connecting rod. The other end of the first connecting rod is connected to the third connecting rod shaft. One end of the thigh close to the calf supports the knee joint shaft. The third connecting rod is respectively rotatably connected to the third connecting rod shaft and the calf. The fourth connecting rod is respectively rotatably connected to the third connecting rod shaft and the knee joint shaft. The fifth connecting rod is rotatably connected to the second connecting rod and the knee joint shaft. The short side end of the fifth connecting rod is rotatably connected to the calf. When the first power source operates, it drives the third connecting rod shaft to rotate around the knee joint shaft through the first connecting rod, the third connecting rod and the fourth connecting rod, and at the same time drives the calf to move through the second connecting rod, thereby realizing the movement of the calf relative to the thigh.

2. The knee joint mechanism of a bionic humanoid robot according to claim 1, characterized in that, The calf supports the calf rotating shaft. The fifth connecting rod is L-shaped. The long side end of the fifth connecting rod is rotatably connected to the second connecting rod through the first connecting rod shaft. The right angle at the middle of the fifth connecting rod is rotatably connected to the knee joint shaft. The other end of the fifth connecting rod is rotatably connected to the calf rotating shaft.

3. The knee joint mechanism of a bionic humanoid robot according to claim 2, characterized in that, One side of the calf close to the thigh is provided with an inclined section. One side of the inclined section close to the first connecting rod is rotatably connected to the third connecting rod, and the other side of the inclined section supports the calf rotating shaft.

4. The knee joint mechanism of a bionic humanoid robot according to claim 2, characterized in that, The calf supports the second connecting rod shaft. The third connecting rod is rotatably connected to the second connecting rod shaft. When the humanoid robot stands, the third connecting rod shaft is arranged higher than the second connecting rod shaft. The central axis of the second connecting rod shaft is located on the front side of the central axis of the knee joint shaft. The central axis of the third connecting rod shaft is higher than the central axis of the knee joint shaft. The first connecting rod shaft is located behind the knee joint shaft.

5. The knee joint mechanism of a bionic humanoid robot according to claim 4, characterized in that, During the process of the humanoid robot from the upright state to the knee-bending state, the second connecting rod shaft gradually comes to the rear side of the third connecting rod shaft.

6. The knee joint mechanism of a bionic humanoid robot according to claim 1, characterized in that, The first connecting rod is connected to the middle section of the third connecting rod shaft. The third connecting rod and the fourth connecting rod are successively arranged on both sides of the first connecting rod with respect to the third connecting rod shaft.

7. The knee joint mechanism of a bionic humanoid robot according to claim 1, characterized in that The thigh includes two side plates. A hollow part is formed between the two side plates. The first connecting rod passes through the hollow parts of the two side plates. One end of the side plate close to the calf is bent outward to form a bent end. The third connecting rod shaft and the knee joint shaft are arranged inside the bent ends of the two side plates. The bent end is arc-shaped. The second connecting rod extends beyond the side plates of the thigh.

8. A bionic humanoid robot, characterized in that, It includes a humanoid robot knee joint mechanism according to any one of claims 1-7. A foot is arranged at the bottom of the calf. A second power source is arranged on one side of the calf close to the thigh. The second power source is connected to the foot to drive the foot to move.

9. The bionic humanoid robot according to claim 8, wherein, The second power source includes two motors. The two motors are respectively connected to the corresponding planetary reduction mechanisms through transmission components. The planetary reduction mechanisms are installed on one side of the calf close to the foot. The planet carrier of one group of planetary reduction mechanisms extends a longitudinal axis forward and backward to be connected to the foot, driving the foot to perform pitching swing relative to the calf. A first bevel gear is arranged on the planet carrier of the other group of planetary reduction mechanisms. The first bevel gear meshes with a second bevel gear fixed on the foot, driving the foot to perform rolling swing relative to the calf.

10. A working method of an imitation humanoid robot according to claim 8 or 9, characterized in that, It includes the following content: The thigh, the rocker, the first link and the fourth link form a four-bar linkage. A part of the fifth link, the third link, the fourth link and the calf form a four-bar linkage. The rocker, the second link, the fifth link and the thigh form a four-bar linkage. When the humanoid robot is in an upright state, when the first power source operates, the third link shaft is pushed to rotate around the knee joint axis through the first link, the third link and the fourth link. At the same time, the calf is driven to move through the second link, thereby realizing the bending of the calf relative to the thigh and realizing the squatting of the humanoid robot. After the humanoid robot squats down, the first power source moves in the reverse direction to realize the straightening movement of the calf relative to the thigh, and the humanoid robot changes from the squatting state to the upright state. The second power source operates to drive the movement of the foot relative to the calf.

Images