Hip joint structure, leg structure and six-degree-of-freedom low-inertia robot bionic leg

Abstract

Hip joint structure, leg structure and robot bionic leg with six degrees of freedom and low inertia belong to bionic legs. In order to solve the problem that the existing humanoid bionic legs cannot achieve multiple degrees of freedom, compact layout, light weight and low inertia at the same time. The present invention includes a hip joint structure and a leg structure; the leg structure includes a thigh, a knee joint connecting shaft, a calf, an ankle joint universal joint assembly, a foot, a knee joint crank rocker drive assembly and an ankle joint crank rocker drive assembly; the thigh is rotatably connected to the calf, and the calf is rotatably connected to the foot through the ankle joint universal joint assembly; the fixed end of the knee joint crank rocker drive assembly is installed on the thigh, and the driving end is hinged to the calf, and drives the calf to swing back and forth to achieve the pitching action of the calf; the fixed end of the ankle joint crank rocker drive assembly is installed on the thigh, and the driving end is connected to the ankle joint universal joint assembly to achieve the pitching action and side swinging action of the foot. The present invention is mainly used for the design of robot legs.

Description

Technical Field

[0001] The invention relates to a leg structure, in particular to a hip joint structure, a leg structure and a robot bionic leg with six degrees of freedom and low inertia. Background Art

[0002] In the past, humanoid robots, as images in film and television works, gave people unlimited imagination. In today's world with rapid development of science and technology, this imagination is gradually becoming a reality. In today's world, countries are actively conducting research on humanoid robot technology. At present, humanoid robot technology has achieved many gratifying research results, but humanoid robot legs, as an important part of robot movement, still have many problems to be solved.

[0003] The leg structure of a humanoid robot includes a thigh, knee joint, calf, ankle joint and foot. In order to achieve the bending of the knee joint and ankle joint, the driving components of the joints are generally installed at the position of the corresponding joints, or the driver for driving the ankle joint is placed at the calf or knee joint, which leads to an increase in the inertia of the calf. For example, the Chinese patent "CN111846008A" discloses "a bipedal robot with a variable stiffness ankle joint", and the driving components include a motor and a gear pair, etc., and the bending of the joint is achieved by the cooperation of the motor and the gear pair. However, this design method results in a large mass at the joint, and it is impossible to achieve lightweight movement of the calf and foot, and it limits the multi-degree-of-freedom movement of the leg.

[0004] At the same time, in order to make the humanoid robot have a higher jumping posture, it is also necessary to equip it with actuators with large torque and high speed; in order to achieve better results, the legs should also be designed to be lightweight, which requires a compact layout of leg components; however, due to the large range of motion of the leg joints, a compact layout is difficult to achieve, which results in an appearance that is not "human" enough. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a hip joint structure, a leg structure and a robot bionic leg with six degrees of freedom and low inertia.

[0006] The technical solution adopted by the present invention to solve the above technical problems is:

[0007] A three-degree-of-freedom hip joint structure, comprising a body connecting part, a hip joint universal joint, a thigh connecting part, two push rod telescopic parts and a hip joint pitch motor; the hip joint universal joint comprises a pin shaft in the y-axis direction and a pin shaft in the z-axis direction, the body connecting part is connected to the two ends of the pin shaft in the y-axis direction of the hip joint universal joint, and rotates around the pin shaft in the y-axis direction of the hip joint universal joint; the two ends of the pin shaft in the z-axis direction of the hip joint universal joint are respectively installed on the thigh connecting part, and the thigh connecting part rotates around the pin shaft in the z-axis direction of the hip joint universal joint; the two push rod telescopic parts The retractable parts are respectively arranged on the front and rear sides of the fuselage connecting part, the connecting end of the push rod telescopic part is connected to the fuselage connecting part through a ball bearing, the protruding end of the push rod telescopic part is connected to the thigh connecting part through a ball bearing, the connecting point of the push rod telescopic part and the thigh connecting part and the connecting point of the push rod telescopic part and the fuselage connecting part are respectively located on both sides of the pin shaft in the z-axis direction of the hip joint universal joint; the axial direction of the output shaft of the hip joint pitch motor is parallel to the x-axis direction, the output end of the hip joint pitch motor is fixedly connected to the end of the leg structure, and drives the leg structure to rotate around the axial direction of the output shaft of the hip joint pitch motor.

[0008] A three-degree-of-freedom leg structure, comprising a thigh, a knee joint connecting shaft, a calf, an ankle joint universal joint assembly, a foot, a knee joint crank rocker drive assembly and an ankle joint crank rocker drive assembly; the lower end of the thigh is rotatably connected to the upper end of the calf through the knee joint connecting shaft, and the lower end of the calf is rotatably connected to the foot through the ankle joint universal joint assembly; the fixed end of the knee joint crank rocker drive assembly is installed at the upper end of the thigh, the driving end of the knee joint crank rocker drive assembly is hinged to the upper end of the calf, and drives the calf to swing back and forth around the axis direction of the knee joint connecting shaft to achieve the pitching action of the calf; the fixed end of the ankle joint crank rocker drive assembly is installed at the middle part of the thigh, and the driving end of the ankle joint crank rocker drive assembly is connected to the ankle joint universal joint assembly to achieve the pitching action and side swinging action of the foot;

[0009] The ankle joint universal joint assembly comprises an ankle joint universal joint and an ankle joint mounting seat, the ankle joint universal joint comprises a pin shaft in the x-axis direction and a pin shaft in the z-axis direction, the lower end of the calf is connected to the two ends of the pin shaft in the x-axis direction of the ankle joint universal joint, and rotates around the pin shaft in the x-axis direction of the ankle joint universal joint; the ankle joint mounting seat is fixedly mounted on the instep of the foot, the two ends of the pin shaft in the z-axis direction of the ankle joint universal joint are respectively rotatably mounted on the ankle joint mounting seat, and the ankle joint mounting seat and the foot rotate around the pin shaft in the z-axis direction of the ankle joint universal joint; a connecting shaft arranged along the x-axis direction is provided on the ankle joint mounting seat at a position close to the heel of the foot;

[0010] The ankle crank rocker drive assembly includes two ankle drive units relatively arranged on both sides of the thigh and the calf, each ankle drive unit includes an ankle drive motor, an ankle crank, an ankle primary connecting rod, an ankle triangle plate and an ankle secondary connecting rod connected in sequence, the ankle drive motor is installed on the thigh, one end of the ankle crank is fixedly connected to the driving end of the ankle drive motor, the other end of the ankle crank is hinged to one end of the ankle primary connecting rod, the other end of the ankle primary connecting rod is hinged to a vertex angle of the ankle triangle plate, the vertex angle 2 of the ankle triangle plate is hinged to the end of the knee joint connecting shaft, the vertex angle 3 of the ankle triangle plate is hinged to one end of the ankle secondary connecting rod through a ball bearing, and the other end of the ankle secondary connecting rod is hinged to the connecting shaft of the ankle mounting seat through a ball bearing; wherein, the vertex angle 1, the vertex angle 2 and the vertex angle 3 of the ankle triangle plate are arranged in sequence, and the ankle primary connecting rod and the ankle secondary connecting rod are respectively located on both sides of the ankle triangle plate.

[0011] A six-degree-of-freedom, low-inertia robot bionic leg, comprising a hip joint structure and a leg structure; the leg structure comprises a thigh, a knee joint connecting shaft, a calf, an ankle joint universal joint assembly, a foot, a knee joint crank rocker drive assembly and an ankle joint crank rocker drive assembly; the lower end of the thigh is rotatably connected to the upper end of the calf through the knee joint connecting shaft, and the lower end of the calf is rotatably connected to the foot through the ankle joint universal joint assembly; the fixed end of the knee joint crank rocker drive assembly is installed at the upper end of the thigh, the driving end of the knee joint crank rocker drive assembly is hinged to the upper end of the calf, and drives the calf to swing back and forth around the axial direction of the knee joint connecting shaft to achieve the pitching action of the calf; the fixed end of the ankle joint crank rocker drive assembly is installed at the middle part of the thigh, and the driving end of the ankle joint crank rocker drive assembly is connected to the ankle joint universal joint assembly to achieve the pitching action and side swinging action of the foot;

[0012] The hip joint structure includes a body connecting part, a hip joint universal joint, a thigh connecting part, two push rod telescopic parts and a hip joint pitch motor; the hip joint universal joint includes a pin in the y-axis direction and a pin in the z-axis direction, the body connecting part is connected to the two ends of the pin in the y-axis direction of the hip joint universal joint, and rotates around the pin in the y-axis direction of the hip joint universal joint; the two ends of the pin in the z-axis direction of the hip joint universal joint are respectively installed on the thigh connecting part, and the thigh connecting part rotates around the pin in the z-axis direction of the hip joint universal joint; the two push rod telescopic parts The parts are respectively arranged on the front and rear sides of the fuselage connecting part, the connecting end of the push rod telescopic part is connected to the fuselage connecting part through a ball bearing, the protruding end of the push rod telescopic part is connected to the thigh connecting part through a ball bearing, the connecting point of the push rod telescopic part and the thigh connecting part and the connecting point of the push rod telescopic part and the fuselage connecting part are respectively located on both sides of the pin shaft in the z-axis direction of the hip joint universal joint; the axial direction of the output shaft of the hip joint pitch motor is parallel to the x-axis direction, and the output end of the hip joint pitch motor is fixedly connected to the end of the thigh, driving the thigh to rotate around the axial direction of the output shaft of the hip joint pitch motor.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. This application makes the overall structure of the leg structure more compact and the appearance more "humanized" through two aspects of design. First, the design of the structural layout: the hip joint structure and the leg structure are both symmetrically designed, and the center plane of the hip joint structure is perpendicular to the center plane of the leg structure, wherein the hip joint pitch motor and the knee joint pitch motor are symmetrically arranged on both sides of the center plane of the leg structure, and the two ankle joint drive units are symmetrically arranged on both sides of the center plane of the leg structure, and are located below the hip joint pitch motor and the knee joint pitch motor, and above the knee joint, that is, the drive motors of the entire leg structure are symmetrically arranged on the thigh, making full use of the space of the thigh, reducing the size of the calf, and making the overall layout compact and the appearance more "humanized". Second, the lightweight design of the calf reduces the size of the drive device: the motor used to drive the ankle joint is placed on the thigh, and no driving components of the robot leg are installed on the calf, so that the mass distribution of the robot leg is closer to the root of the thigh, reducing the inertia of the calf, and lowering the requirements for the calf drive device, thereby reducing the size of the drive device, making the layout more compact and closer to the shape of human legs, while providing the possibility of achieving higher motion performance; and the electric cylinder used to drive the hip joint has a compressed height dimension, which is more "anthropomorphic" and beautiful.

[0015] 2. The present application adopts the design of the knee joint crank rocker drive assembly so that the foot can be lifted together with the calf and always remain in a horizontal state without changing the posture while the calf undergoes pitch motion; the design of the ankle joint crank rocker drive assembly allows the foot to achieve pitch motion or side swing motion without affecting the position and movement posture of the calf. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings are incorporated as part of this application and are used to provide a further understanding of the present invention.

[0017] Figure 1 The axis side of the bionic leg of Example 3 of the present invention Figure 1 .

[0018] Figure 2 This is a partial enlarged view of the knee joint in the leg structure of Example 2 of the present invention.

[0019] Figure 3 This is a left view of the bionic leg according to Example 3 of the present invention.

[0020] Figure 4 It is a right view of the leg structure of embodiment 2 of the present invention.

[0021] Figure 5 This is a front view three-dimensional modeling diagram of the bionic leg in Example 3 of the present invention.

[0022] Figure 6 This is the main line of sight bar diagram of the bionic leg in Example 3 of the present invention.

[0023] Figure 7 This is an axonometric view of the hip joint structure of Example 1 of the present invention.

[0024] Figure 8 This is a schematic structural diagram of the bionic leg in a bent state in Example 3 of the present invention.

[0025] Fig. 9 This is an axonometric view of the bionic leg in a bent state according to Example 3 of the present invention.

[0026] Fig.10 This is a three-dimensional modeling diagram of the hip joint structure in the yaw state according to Example 1 of the present invention.

[0027] Fig.11 It is a line diagram of the deflection state of the hip joint structure in Example 1 of the present invention.

[0028] Fig.12 This is a three-dimensional modeling diagram of the bionic leg in the side-swing state according to Example 3 of the present invention.

[0029] Fig.13 It is a line drawing of the side-swinging state of the bionic leg in Example 3 of the present invention.

[0030] Explanation of the reference numerals: A-hip joint structure; B-leg structure; 1-body connecting piece; 1-1-connecting ear; 2-hip joint universal joint; 2-1-pin shaft one; 2-2-pin shaft two; 3-thigh connecting piece; 3-1-mounting seat; 3-2-second connecting ear; 4-push rod telescopic piece; 5-hip joint pitch motor; 6-thigh; 6-1-notch; 6-2-connecting ring; 6-3-connecting plate; 7-knee joint connecting shaft; 8-calf; 9-ankle joint universal joint assembly; 9-1-ankle joint universal joint; 9-1-1-pin shaft three; 9-1-2-pin shaft four ;9-2-ankle joint mounting seat;9-2-1-connecting shaft;10-foot;11-knee joint crank rocker drive assembly;11-1-knee joint pitch motor;11-2-knee joint crank;11-3-knee joint motion connecting rod;12-ankle joint crank rocker drive assembly;12-1-ankle joint drive motor;12-2-ankle joint crank;12-3-ankle joint primary connecting rod;12-4-ankle joint triangle plate;12-4-1-vertex one;12-4-2-vertex two;12-4-3-vertex three;12-5-ankle joint secondary connecting rod. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0032] Embodiment 1:

[0033] This embodiment solves the problem that the existing hip joint structure cannot achieve multiple degrees of freedom, and thus provides a hip joint structure with three degrees of freedom. Figures 1 to 13 The hip joint structure A is used to connect the leg structure B with the robot body, and can realize the three degrees of freedom of the leg structure B, namely the side swing, yaw and pitch of the leg structure B. Figure 1 The hip joint structure A includes a body connecting part 1, a hip joint universal joint 2, a thigh connecting part 3, two push rod telescopic parts 4 and a hip joint pitch motor 5; the body connecting part 1 is used to connect the hip joint with the robot body part, the thigh connecting part 3 is used to connect the hip joint with the thigh, the hip joint universal joint 2 is used to connect the body connecting part 1 with the thigh connecting part 3, and at the same time, the side swing and yaw movements of the thigh are realized under the action of the two push rod telescopic parts 4, and the hip joint pitch motor 5 is installed on the thigh connecting part 3 and connected to the end of the thigh 6 to realize the pitch movement of the thigh.

[0034] See also Figure 7 , Fig.10 , Fig.11, the hip joint universal joint 2 includes two vertically arranged pins, namely a pin 1 2-1 in the y-axis direction and a pin 2-2 in the z-axis direction, so the hip joint universal joint 2 has two degrees of freedom, namely a degree of freedom for rotation around the y-axis direction and a degree of freedom for rotation around the z-axis direction; a connecting ear 1-1 is arranged on the side of the fuselage connecting member 1 and extends toward the x-axis direction, the connecting ear 1-1 is connected to the two ends of the pin 1 2-1 in the y-axis direction of the hip joint universal joint 2, and can rotate around the pin 1 2-1; a mounting seat 3-1 is arranged on the top of the thigh connecting member 3, and the two ends of the pin 2-2 in the z-axis direction of the hip joint universal joint 2 are respectively installed on the two brackets of the mounting seat 3-1, and the thigh connecting member 3 can rotate around the pin 2-2 in the z-axis direction of the hip joint universal joint 2; the mounting seat 3- Two second connecting ears 3-2 are eccentrically arranged on the side facing away from the fuselage connecting member 1, and the two second connecting ears 3-2 are relatively arranged at the two ends of the mounting seat 3-1 in the z-axis direction; the two push rod telescopic members 4 are respectively arranged on the front and rear sides of the fuselage connecting member 1, the connecting end of the push rod telescopic member 4 is connected to the fuselage connecting member 1 through a ball bearing, and the protruding end of the push rod telescopic member 4 is connected to the second connecting ear 3-2 through a ball bearing, and the connection point of the push rod telescopic member 4 and the thigh connecting member 3 and the connection point of the push rod telescopic member 4 and the fuselage connecting member 1 are respectively located on both sides of the pin shaft 2-2 in the z-axis direction of the hip joint universal joint 2; the hip joint pitch motor 5 is installed on the thigh connecting member 3, the axial direction of the output shaft of the hip joint pitch motor 5 is parallel to the x-axis direction, and the output end of the hip joint pitch motor 5 is fixedly connected to the end of the thigh 6 to drive the thigh 6 to rotate around the x-axis direction.

[0035] Furthermore, the push rod telescopic member 4 is an electric cylinder to reduce the volume and mass at the hip joint.

[0036] In this embodiment, the hip joint universal joint 2 provides two degrees of freedom for the hip joint structure A, and under the coupling action of the two electric cylinders, the side swing and yaw movements of the leg structure B are realized; the hip joint pitch motor 5 provides one degree of freedom for the hip joint structure A, and the pitch movement of the leg structure B is realized through the drive of the hip joint pitch motor 5.

[0037] Embodiment 2:

[0038] This embodiment is to solve the problem that the existing leg structure cannot achieve multiple degrees of freedom, has large inertia and a large overall structure size, and thus provides a three-degree-of-freedom, low-inertia leg structure, see Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 8 , Fig. 9 , Fig.12 , Fig.13 , which includes a thigh 6, a knee joint connecting shaft 7, a calf 8, an ankle joint universal joint assembly 9, a foot 10, a knee joint crank rocker drive assembly 11 and an ankle joint crank rocker drive assembly 12; the lower end of the thigh 6 is rotatably connected to the upper end of the calf 8 through the knee joint connecting shaft 7, and the lower end of the calf 8 is rotatably connected to the foot 10 through the ankle joint universal joint assembly 9; the fixed end of the knee joint crank rocker drive assembly 11 is installed at the upper end of the thigh 6, the driving end of the knee joint crank rocker drive assembly 11 is hinged to the upper end of the calf 8, and drives the calf 8 to swing back and forth around the axial direction of the knee joint connecting shaft 7 to achieve the pitching movement of the calf 8; the fixed end of the ankle joint crank rocker drive assembly 12 is installed at the middle part of the thigh 6, and the driving end of the ankle joint crank rocker drive assembly 12 is connected to the ankle joint universal joint assembly 9 to achieve the pitching movement and side swinging movement of the foot.

[0039] See also Figure 4 and Figure 6 The thigh 6 is a hollow shell structure, and a notch 6-1 is opened at the lower end of the thigh 6, which runs through the front and back, and a connecting ring 6-2 is respectively arranged on the left and right sides of the notch 6-1. The upper end of the calf 8 is inserted into the notch 6-1 at the lower end of the thigh 6, and the thigh 6 is respectively mounted on the knee joint connecting shaft 7 arranged along the x-axis direction through a rotating bearing. The notch 6-1 provides a rotation space for the calf 8; a connecting plate 6-3 is respectively arranged on the left and right sides of the middle position of the thigh 6, and the fixed ends of the ankle crank rocker drive assembly 12 are installed on the two connecting plates 6-3.

[0040] See also Figure 7 , Fig.10 and Fig.11The ankle joint universal joint assembly 9 includes an ankle joint universal joint 9-1 and an ankle joint mounting seat 9-2. The ankle joint universal joint 9-1 includes two vertically arranged pins, namely, a pin three 9-1-1 in the x-axis direction and a pin four 9-1-2 in the z-axis direction. Therefore, the ankle joint universal joint 9-1 has two degrees of freedom, namely, a degree of freedom for rotation around the x-axis direction and a degree of freedom for rotation around the z-axis direction; the lower end of the calf 8 is connected to the two ends of the pin three 9-1-1 in the x-axis direction of the ankle joint universal joint 9-1, and can rotate around the pin three 9-1-2. -1-1 is used for rotation; the ankle joint mounting seat 9-2 is fixedly mounted on the instep of the foot 10, and the two ends of the pin shaft 9-1-2 in the z-axis direction of the ankle joint universal joint 9-1 are rotatably mounted on the ankle joint mounting seat 9-2 respectively, and the ankle joint mounting seat 9-2 and the foot 10 can rotate around the pin shaft 9-1-2; a connecting shaft 9-2-1 arranged along the x-axis direction is provided on the ankle joint mounting seat 9-2 near the heel of the foot 10, and the driving end of the knee crank rocker drive assembly 11 is rotatably connected to the connecting shaft 9-2-1.

[0041] See also Figure 4 The knee crank rocker drive assembly 11 includes a knee pitch motor 11-1, a knee crank 11-2 and a knee motion connecting rod 11-3; the knee pitch motor 11-1 is coaxially arranged with the hip pitch motor 5, the output end of the knee pitch motor 11-1 is fixedly connected to one end of the knee crank 11-2, the other end of the knee crank 11-2 is hinged to one end of the knee motion connecting rod 11-3, and the other end of the knee motion connecting rod 11-3 is hinged to the connecting ear at the top of the calf 8.

[0042] Furthermore, the knee joint motion link 11-3 includes link 1 and link 2, one end of link 1 is hinged to the end of the knee joint crank 11-2, the other end of link 1 is hinged to one end of link 2, and the other end of link 2 is hinged to the connecting ear at the top of the calf 8.

[0043] Furthermore, the connection end between the second connecting rod and the calf 8 is curved to achieve the maximum bending degree of the leg.

[0044] See also Figure 6The ankle joint crank rocker drive assembly 12 includes two ankle joint drive units relatively arranged on both sides of the thigh 6 and the calf 8, each ankle joint drive unit includes an ankle joint drive motor 12-1, an ankle joint crank 12-2, an ankle joint primary connecting rod 12-3, an ankle joint triangle plate 12-4 and an ankle joint secondary connecting rod 12-5 connected in sequence, the ankle joint drive motor 12-1 is installed on the connecting plate 6-3 on the side of the thigh 6, one end of the ankle joint crank 12-2 is fixedly connected to the ankle The driving end of the joint driving motor 12-1, the other end of the ankle joint crank 12-2 is hinged to one end of the ankle joint primary connecting rod 12-3, the other end of the ankle joint primary connecting rod 12-3 is hinged to the vertex 1 12-4-1 of the ankle joint triangle plate 12-4, the vertex 2 12-4-2 of the ankle joint triangle plate 12-4 is hinged to the end of the knee joint connecting shaft 7, and the vertex 3 12-4-3 of the ankle joint triangle plate 12-4 is hinged to one end of the ankle joint secondary connecting rod 12-5 through a ball bearing. The other end of the ankle joint secondary connecting rod 12-5 is connected to the connecting shaft 9-2-1 of the ankle joint mounting seat 9-2 through a ball bearing hinge; wherein, the vertex one 12-4-1, the vertex two 12-4-2 and the vertex three 12-4-3 of the ankle joint triangle plate 12-4 are arranged in sequence in the clockwise direction, and the ankle joint primary connecting rod 12-3 and the ankle joint secondary connecting rod 12-5 are respectively located on both sides of the ankle joint triangle plate 12-4; the ankle joint crank 12-2, the ankle joint primary connecting rod 12-3, the ankle joint The edge between the vertex 1 12-4-1 and the vertex 2 12-4-2 of the triangle plate 12-4 and the line between the knee joint connecting shaft 7 and the ankle joint driving motor 12-1 form an upper parallelogram structure; the edge between the vertex 2 12-4-2 and the vertex 3 12-4-3 of the ankle joint triangle plate 12-4, the ankle joint secondary connecting rod 12-5, the connecting shaft 9-2-1 and the line between the pin shaft in the x-axis direction of the ankle joint universal joint 9-1 and the calf 8 form a lower parallelogram structure.

[0045] In this embodiment, the knee joint crank rocker drive assembly 11 and the ankle joint crank rocker drive assembly 12 are symmetrically mounted on the thigh 6, making the entire leg structure compact and more "human" in appearance. At the same time, since there are no driving components on the calf 8, the weight on the calf 8 is small, the leg inertia is reduced, the requirements for the motor, electric cylinder and other devices driving the leg are further reduced, and the size and mass are further reduced, thereby achieving lightweight legs.

[0046] Embodiment 3:

[0047] In order to solve the problem that the existing humanoid bionic legs cannot achieve multiple degrees of freedom, compact layout, light weight and low inertia at the same time, this embodiment provides a six-degree-of-freedom, low-inertia robot bionic leg. Figures 1 to 13, which includes a hip joint structure A and a leg structure B; the hip joint structure A is used to connect the leg structure B with the body parts of the robot, and can realize the three degrees of freedom of the leg structure B, namely, the side swing, yaw and pitch of the leg structure B; the leg structure B itself has three degrees of freedom, namely, the pitch movement of the knee joint, the pitch and side swing of the ankle joint.

[0048] See also Figure 3 , Figure 7 , Fig.10 and Fig.11 The hip joint structure A includes a body connecting part 1, a hip joint universal joint 2, a thigh connecting part 3, two push rod telescopic parts 4 and a hip joint pitch motor 5; the body connecting part 1 is used to connect the hip joint with the robot body part, the thigh connecting part 3 is used to connect the hip joint with the thigh, the hip joint universal joint 2 is used to connect the body connecting part 1 with the thigh connecting part 3, and at the same time, the side swing and yaw movements of the thigh are realized under the action of the two push rod telescopic parts 4, and the hip joint pitch motor 5 is installed on the thigh connecting part 3 and connected to the end of the thigh 6 to realize the pitch movement of the thigh.

[0049] See also Fig.10 The hip joint universal joint 2 includes two vertically arranged pins, namely a pin 1 2-1 in the y-axis direction and a pin 2-2 in the z-axis direction, so the hip joint universal joint 2 has two degrees of freedom, namely a degree of freedom for rotation around the y-axis direction and a degree of freedom for rotation around the z-axis direction; a connecting ear 1-1 is arranged on the side of the fuselage connecting member 1 and extends toward the x-axis direction, the connecting ear 1-1 is connected to the two ends of the pin 1 2-1 in the y-axis direction of the hip joint universal joint 2, and can rotate around the pin 1 2-1; a mounting seat 3-1 is arranged on the top of the thigh connecting member 3, and the two ends of the pin 2-2 in the z-axis direction of the hip joint universal joint 2 are respectively mounted on the two brackets of the mounting seat 3-1, and the thigh The connecting member 3 can rotate around the pin shaft 2-2; the mounting seat 3-1 is also eccentrically provided with two second connecting ears 3-2 on the side facing away from the fuselage connecting member 1, and the two second connecting ears 3-2 are relatively arranged at both ends of the z-axis direction in the mounting seat 3-1; the two push rod telescopic members 4 are respectively arranged on the front and rear sides of the fuselage connecting member 1, and the connecting end of the push rod telescopic member 4 is connected to the fuselage connecting member 1 through a ball bearing, and the protruding end of the push rod telescopic member 4 is connected to the second connecting ear 3-2 through a ball bearing; the hip joint pitch motor 5 is installed on the thigh connecting member 3, and the axial direction of the output shaft of the hip joint pitch motor 5 is parallel to the x-axis direction, and the output end of the hip joint pitch motor 5 is fixedly connected to the end of the thigh 6, driving the thigh 6 to rotate around the x-axis direction.

[0050] Furthermore, the push rod telescopic member 4 is an electric cylinder.

[0051] See also Figures 1 to 6 The leg structure B includes a thigh 6, a knee joint connecting shaft 7, a calf 8, an ankle joint universal joint assembly 9, a foot 10, a knee joint crank rocker drive assembly 11 and an ankle joint crank rocker drive assembly 12; the lower end of the thigh 6 is rotatably connected to the upper end of the calf 8 through the knee joint connecting shaft 7, and the lower end of the calf 8 is rotatably connected to the foot 10 through the ankle joint universal joint assembly 9; the fixed end of the knee joint crank rocker drive assembly 11 is installed at the upper end of the thigh 6, the driving end of the knee joint crank rocker drive assembly 11 is hinged to the upper end of the calf 8, and drives the calf 8 to swing back and forth around the axial direction of the knee joint connecting shaft 7 to achieve the pitching action of the calf 8; the fixed end of the ankle joint crank rocker drive assembly 12 is installed at the middle part of the thigh 6, and the driving end of the ankle joint crank rocker drive assembly 12 is connected to the ankle joint universal joint assembly 9 to achieve the pitching action and side swinging action of the foot.

[0052] See also Figure 4 and Figure 6 The thigh 6 is a hollow shell structure, and a notch 6-1 is opened at the lower end of the thigh 6, which runs through the front and back, and a connecting ring 6-2 is respectively arranged on the left and right sides of the notch 6-1. The upper end of the calf 8 is inserted into the notch 6-1 at the lower end of the thigh 6, and the thigh 6 is respectively mounted on the knee joint connecting shaft 7 arranged along the x-axis direction through a rotating bearing. The notch 6-1 provides a rotation space for the calf 8; a connecting plate 6-3 is respectively arranged on the left and right sides of the middle position of the thigh 6, and the fixed ends of the ankle crank rocker drive assembly 12 are installed on the two connecting plates 6-3.

[0053] See also Figure 4 The ankle joint universal joint assembly 9 includes an ankle joint universal joint 9-1 and an ankle joint mounting seat 9-2. The ankle joint universal joint 9-1 includes two vertically arranged pins, namely, a pin three 9-1-1 in the x-axis direction and a pin four 9-1-2 in the z-axis direction. Therefore, the ankle joint universal joint 9-1 has two degrees of freedom, namely, a degree of freedom for rotation around the x-axis direction and a degree of freedom for rotation around the z-axis direction; the lower end of the calf 8 is connected to the two ends of the pin three 9-1-1 in the x-axis direction of the ankle joint universal joint 9-1, and can rotate around the pin three 9-1-2. -1-1 is used for rotation; the ankle joint mounting seat 9-2 is fixedly mounted on the instep of the foot 10, and the two ends of the pin shaft 9-1-2 in the z-axis direction of the ankle joint universal joint 9-1 are rotatably mounted on the ankle joint mounting seat 9-2 respectively, and the ankle joint mounting seat 9-2 and the foot 10 can rotate around the pin shaft 9-1-2; a connecting shaft 9-2-1 arranged along the x-axis direction is provided on the ankle joint mounting seat 9-2 near the heel of the foot 10, and the driving end of the knee crank rocker drive assembly 11 is rotatably connected to the connecting shaft 9-2-1.

[0054] See also Figure 4 The knee crank rocker drive assembly 11 includes a knee pitch motor 11-1, a knee crank 11-2 and a knee motion connecting rod 11-3; the knee pitch motor 11-1 is coaxially arranged with the hip pitch motor 5, the output end of the knee pitch motor 11-1 is fixedly connected to one end of the knee crank 11-2, the other end of the knee crank 11-2 is hinged to one end of the knee motion connecting rod 11-3, and the other end of the knee motion connecting rod 11-3 is hinged to the connecting ear at the top of the calf 8.

[0055] Furthermore, the knee joint motion link 11-3 includes link 1 and link 2, one end of link 1 is hinged to the end of the knee joint crank 11-2, the other end of link 1 is hinged to one end of link 2, and the other end of link 2 is hinged to the connecting ear at the top of the calf 8.

[0056] Furthermore, the connection end between the second connecting rod and the calf 8 is curved to achieve the maximum bending degree of the leg.

[0057] See also Figure 6The ankle joint crank rocker drive assembly 12 includes two ankle joint drive units relatively arranged on both sides of the thigh 6 and the calf 8, each ankle joint drive unit includes an ankle joint drive motor 12-1, an ankle joint crank 12-2, an ankle joint primary connecting rod 12-3, an ankle joint triangle plate 12-4 and an ankle joint secondary connecting rod 12-5 connected in sequence, the ankle joint drive motor 12-1 is installed on the connecting plate 6-3 on the side of the thigh 6, one end of the ankle joint crank 12-2 is fixedly connected to the ankle The driving end of the joint driving motor 12-1, the other end of the ankle joint crank 12-2 is hinged to one end of the ankle joint primary connecting rod 12-3, the other end of the ankle joint primary connecting rod 12-3 is hinged to the vertex 1 12-4-1 of the ankle joint triangle plate 12-4, the vertex 2 12-4-2 of the ankle joint triangle plate 12-4 is hinged to the end of the knee joint connecting shaft 7, and the vertex 3 12-4-3 of the ankle joint triangle plate 12-4 is hinged to one end of the ankle joint secondary connecting rod 12-5 through a ball bearing. The other end of the ankle joint secondary connecting rod 12-5 is connected to the connecting shaft 9-2-1 of the ankle joint mounting seat 9-2 through a ball bearing hinge; wherein, the vertex one 12-4-1, the vertex two 12-4-2 and the vertex three 12-4-3 of the ankle joint triangle plate 12-4 are arranged in sequence in the clockwise direction, and the ankle joint primary connecting rod 12-3 and the ankle joint secondary connecting rod 12-5 are respectively located on both sides of the ankle joint triangle plate 12-4; the ankle joint crank 12-2, the ankle joint primary connecting rod 12-3, the ankle joint The edge between the vertex 1 12-4-1 and the vertex 2 12-4-2 of the triangle plate 12-4 and the line between the knee joint connecting shaft 7 and the ankle joint driving motor 12-1 form an upper parallelogram structure; the edge between the vertex 2 12-4-2 and the vertex 3 12-4-3 of the ankle joint triangle plate 12-4, the ankle joint secondary connecting rod 12-5, the connecting shaft 9-2-1 and the line between the pin shaft in the x-axis direction of the ankle joint universal joint 9-1 and the calf 8 form a lower parallelogram structure.

[0058] In this embodiment, the overall structure of the leg structure B is made more compact and the appearance is more "humanized" through two aspects of design. First, the design of the structural layout: the hip joint structure A and the leg structure B are both symmetrically designed, and the median plane of the hip joint structure A is perpendicular to the median plane of the leg structure B, wherein the hip joint pitch motor 5 and the knee joint pitch motor 11-1 are symmetrically arranged on both sides of the median plane of the leg structure B, and the two ankle joint drive units are symmetrically arranged on both sides of the median plane of the leg structure B, and are located below the hip joint pitch motor 5 and the knee joint pitch motor 11-1, and above the knee joint, that is, the drive motors of the entire leg structure B are symmetrically arranged on the thigh 6, making full use of the space of the thigh, reducing the size of the calf, and making the overall layout compact and the appearance more "humanized". Second, the lightweight design of the calf reduces the size of the drive device: the motor used to drive the ankle joint is placed on the thigh, and no driving components of the robot leg are installed on the calf, so that the mass distribution of the robot leg is closer to the root of the thigh, reducing the inertia of the calf, and lowering the requirements for the calf drive device, thereby reducing the size of the drive device, making the layout more compact and closer to the shape of human legs, while providing the possibility of achieving higher motion performance; and the electric cylinder used to drive the hip joint has a compressed height dimension, which is more "anthropomorphic" and beautiful.

[0059] In this embodiment, the design of the knee joint crank rocker drive assembly 11 allows the foot to be lifted together with the calf 8 and always remain in a horizontal state without changing its posture; the design of the ankle joint crank rocker drive assembly 12 allows the foot to achieve pitch or side swing motion without affecting the position and movement posture of the calf.

[0060] The working process of the present invention is further described below to further demonstrate the working principle and advantages of the present invention:

[0061] 1. The process of leg side swing movement:

[0062] See also Fig.12 and Fig.13 When the fuselage connecting part 1 is connected to the fuselage and remains fixed, the telescopic rods of the two electric cylinders extend out of the cylinder body synchronously and the extended lengths are the same, the telescopic rods of the electric cylinders generate the same thrust on the thigh connecting part 3. Under the action of the eccentric thrust, the thigh connecting part 3 rotates upward around the pin axis in the z-axis direction of the hip joint universal joint 2, and drives the leg structure to swing to the side of the fuselage, thereby realizing the freedom of side swing of the leg.

[0063] 2. The process of leg yaw movement:

[0064] See also Fig.10 and Fig.11When the telescopic rods of the two electric cylinders extend out of the cylinder body successively and the extended lengths are different, the thigh connector 3 rotates around the pin shaft in the y-axis direction of the hip joint universal joint 2 under the coupling action of the telescopic rods of the two electric cylinders. When the telescopic rod of the electric cylinder in front of the fuselage extends longer and the telescopic rod of the electric cylinder behind the fuselage extends shorter, the thigh connector 3 drives the leg structure to rotate clockwise. Conversely, the thigh connector 3 drives the leg structure to rotate counterclockwise, thereby realizing the yaw freedom of the leg.

[0065] 3. The process of leg pitching movement:

[0066] When the driving shaft of the hip joint pitch motor 5 drives the thigh 6 to swing forward and backward, the pitch freedom of the leg is achieved.

[0067] 4. The process of calf pitching movement:

[0068] See also Figure 8 The rotational motion of the knee joint pitch motor 11-1 is transmitted to the calf 8 through the knee joint crank 11-2 and the knee joint motion connecting rod 11-3 in turn, and drives the calf 8 to perform pitch motion around the knee joint connecting axis 7, and at the same time, the calf 8 drives the foot 10 to lift; since the ankle joint drive motor 12-1 is not started, the shape of the upper parallelogram structure at the top has not changed, and the position of the ankle joint triangle plate 12-4 has not changed, so the top side state and the bottom side state in the lower parallelogram structure will not change, and the foot 10 is always parallel to the ground, but the angle between the foot 10 and the calf 8 changes, so the rotational motion of the knee joint pitch motor 11-1 can change the pitch angle of the calf 8 without changing the pitch angle of the foot 10.

[0069] 5. The process of foot pitching movement:

[0070] See also Figure 8The ankle joint drive motors 12-1 in the two ankle joint drive units are driven synchronously in the same direction, and the rotational motion of the ankle joint drive motor 12-1 is transmitted to the foot 10 through the ankle joint crank 12-2, the ankle joint primary connecting rod 12-3, the ankle joint triangle plate 12-4 and the ankle joint secondary connecting rod 12-5 in turn, and the foot 10 undergoes a pitch motion; specifically, the ankle joint drive motor 12-1 drives the ankle joint crank 12-2 to rotate counterclockwise, the ankle joint crank 12-2 drives the ankle joint triangle plate 12-4 to rotate counterclockwise around the knee joint connecting shaft 7 through the ankle joint primary connecting rod 12-3, and the ankle joint triangle plate 12-4 drives the foot 10 to rotate counterclockwise around the pin shaft in the x-axis direction of the ankle joint universal joint 9-1 through the ankle joint secondary connecting rod 12-5. When the ankle joint rotates clockwise, the toes of the foot 10 turn downward; conversely, the ankle joint drive motor 12-1 drives the ankle joint crank 12-2 to rotate clockwise, and the ankle joint crank 12-2 drives the ankle joint triangle plate 12-4 to rotate clockwise around the knee joint connecting axis 7 through the ankle joint primary connecting rod 12-3, and the ankle joint triangle plate 12-4 drives the foot 10 to rotate clockwise around the pin shaft in the x-axis direction of the ankle joint universal joint 9-1 through the ankle joint secondary connecting rod 12-5, and the toes of the foot 10 turn upward, so the pitch posture of the foot 10 changes; because the ankle joint secondary connecting rod 12-5 is always in a vertical state, the state and position of the calf 8 do not change, and the ankle joint drive motor 12-1 only changes the pitch angle of the foot 10.

[0071] 6. The process of lateral swing of the foot:

[0072] When the ankle joint drive motors 12-1 in the two ankle joint drive units are driven in reverse synchronously, the foot 10 performs a sideways swing motion under the coupled drive of the two ankle joint drive motors 12-1; specifically, the ankle joint drive motor 12-1 in the left ankle joint drive unit rotates counterclockwise at a small angle, and the left ankle joint secondary connecting rod 12-5 drives the left heel side of the foot 10 to be pulled upward, and the ankle joint drive motor 12-1 in the right ankle joint drive unit rotates clockwise at a small angle, and the right ankle joint secondary connecting rod 12-5 drives the right heel side of the foot 10 to move downward, and the foot 10 Under the coupling action of the two, the foot 10 swings to the right around the pin axis in the z-axis direction of the ankle joint universal joint 9-1; conversely, the ankle joint drive motor 12-1 in the ankle joint drive unit on the left side rotates clockwise at a small angle, and the ankle joint secondary connecting rod 12-5 on the left side drives the left heel side of the foot 10 to move downward, and the ankle joint drive motor 12-1 in the ankle joint drive unit on the right side rotates counterclockwise at a small angle, and the ankle joint secondary connecting rod 12-5 on the right side drives the right heel side of the foot 10 to move upward, and the foot 10 swings to the left around the pin axis in the z-axis direction of the ankle joint universal joint 9-1 under the coupling action of the two.

[0073] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be used in other described embodiments.

Claims

1. A three-degree-of-freedom leg structure, characterized in that: The invention comprises a thigh (6), a knee joint connecting shaft (7), a calf (8), an ankle joint universal joint assembly (9), a foot (10), a knee joint crank rocker drive assembly (11) and an ankle joint crank rocker drive assembly (12); the lower end of the thigh (6) is rotatably connected to the upper end of the calf (8) via the knee joint connecting shaft (7), and the lower end of the calf (8) is rotatably connected to the foot (10) via the ankle joint universal joint assembly (9); the fixed end of the knee joint crank rocker drive assembly (11) is mounted on the thigh ( The driving end of the knee joint crank rocker driving assembly (11) is hingedly connected to the upper end of the calf (8) and drives the calf (8) to swing forward and backward around the axis of the knee joint connecting shaft (7) to achieve the pitching movement of the calf (8); the fixed end of the ankle joint crank rocker driving assembly (12) is installed at the middle part of the thigh (6), and the driving end of the ankle joint crank rocker driving assembly (12) is connected to the ankle joint universal joint assembly (9) to achieve the pitching movement and side swinging movement of the foot; The ankle joint universal joint assembly (9) comprises an ankle joint universal joint (9-1) and an ankle joint mounting seat (9-2), wherein the ankle joint universal joint (9-1) comprises a pin shaft three (9-1-1) in the x-axis direction and a pin shaft four (9-1-2) in the z-axis direction, wherein the lower end of the calf (8) is connected to the two ends of the pin shaft three (9-1-1) and rotates around the pin shaft three (9-1-1); the ankle joint mounting seat (9-2) is fixedly mounted on the instep of the foot (10), and the two ends of the pin shaft four (9-1-2) in the ankle joint universal joint (9-1) are respectively rotatably mounted on the ankle joint mounting seat (9-2), and the ankle joint mounting seat (9-2) and the foot (10) rotate around the pin shaft four (9-1-2); a connecting shaft (9-2-1) arranged along the x-axis direction is provided on the ankle joint mounting seat (9-2) at a position close to the heel of the foot (10); The ankle joint crank rocker drive assembly (12) comprises two ankle joint drive units arranged relatively on both sides of the thigh (6) and the calf (8), each ankle joint drive unit comprises an ankle joint drive motor (12-1), an ankle joint crank (12-2), an ankle joint primary connecting rod (12-3), an ankle joint triangle plate (12-4) and an ankle joint secondary connecting rod (12-5) connected in sequence, the ankle joint drive motor (12-1) is mounted on the thigh (6), one end of the ankle joint crank (12-2) is fixedly connected to the driving end of the ankle joint drive motor (12-1), the other end of the ankle joint crank (12-2) is hingedly connected to one end of the ankle joint primary connecting rod (12-3), and the other end of the ankle joint primary connecting rod (12-3) is hingedly connected to the ankle joint triangle plate (12-4). ), the second vertex angle (12-4-2) of the ankle joint triangle plate (12-4) is hingedly connected to the end of the knee joint connecting shaft (7), the third vertex angle (12-4-3) of the ankle joint triangle plate (12-4) is hingedly connected to one end of the ankle joint secondary connecting rod (12-5) through a ball bearing, and the other end of the ankle joint secondary connecting rod (12-5) is hingedly connected to the connecting shaft (9-2-1) of the ankle joint mounting seat (9-2) through a ball bearing; wherein the first vertex angle (12-4-1), the second vertex angle (12-4-2) and the third vertex angle (12-4-3) of the ankle joint triangle plate (12-4) are sequentially arranged in a clockwise direction, and the ankle joint primary connecting rod (12-3) and the ankle joint secondary connecting rod (12-5) are respectively located on both sides of the ankle joint triangle plate (12-4); The lower end of the thigh (6) is provided with a notch (6-1) that passes through from front to back, the upper end of the calf (8) is inserted into the notch (6-1) at the lower end of the thigh (6), and the calf (8) and the thigh (6) are respectively mounted on a knee joint connecting shaft (7) arranged along the x-axis direction; a connecting plate (6-3) is respectively arranged on the left and right sides of the middle position of the thigh (6), and an ankle joint driving motor (12-1) is mounted on the connecting plate (6-3); The knee joint crank rocker drive assembly (11) comprises a knee joint pitch motor (11-1), a knee joint crank (11-2) and a knee joint motion connecting rod (11-3); the output end of the knee joint pitch motor (11-1) is fixedly connected to one end of the knee joint crank (11-2), the other end of the knee joint crank (11-2) is hingedly connected to one end of the knee joint motion connecting rod (11-3), and the other end of the knee joint motion connecting rod (11-3) is hingedly connected to a connecting ear at the top of the calf (8); the knee joint motion connecting rod (11-3) comprises a connecting rod 1 and a connecting rod 2, one end of the connecting rod 1 is hingedly connected to the end of the knee joint crank (11-2), the other end of the connecting rod 1 is hingedly connected to one end of the connecting rod 2, and the other end of the connecting rod 2 is hingedly connected to the connecting ear at the top of the calf (8); the end of the connecting rod 2 connected to the calf (8) is bent to achieve a maximum bending degree of the leg.

2. A six-degree-of-freedom, low-inertia robot bionic leg, characterized by: It includes the hip joint structure (A) and the leg structure (B); The leg structure (B) comprises a thigh (6), a knee joint connecting shaft (7), a calf (8), an ankle joint universal joint assembly (9), a foot (10), a knee joint crank rocker drive assembly (11) and an ankle joint crank rocker drive assembly (12); the lower end of the thigh (6) is rotatably connected to the upper end of the calf (8) via the knee joint connecting shaft (7), and the lower end of the calf (8) is rotatably connected to the foot (10) via the ankle joint universal joint assembly (9); the fixed end of the knee joint crank rocker drive assembly (11) is arranged The knee joint crank rocker drive assembly (11) is mounted on the upper end of the thigh (6), and the driving end of the knee joint crank rocker drive assembly (11) is hingedly connected to the upper end of the calf (8), and drives the calf (8) to swing forward and backward around the axis direction of the knee joint connection shaft (7), thereby realizing the pitching movement of the calf (8); the fixed end of the ankle joint crank rocker drive assembly (12) is mounted on the middle part of the thigh (6), and the driving end of the ankle joint crank rocker drive assembly (12) is connected to the ankle joint universal joint assembly (9), so as to realize the pitching movement and sideways movement of the foot; The hip joint structure (A) comprises a body connecting part (1), a hip joint universal joint (2), a thigh connecting part (3), two push rod telescopic parts (4) and a hip joint pitch motor (5); the hip joint universal joint (2) comprises a pin shaft 1 (2-1) in the y-axis direction and a pin shaft 2 (2-2) in the z-axis direction, the body connecting part (1) is connected to both ends of the pin shaft 1 (2-1) and rotates around the pin shaft 1 (2-1); both ends of the pin shaft 2 (2-2) in the hip joint universal joint (2) are respectively mounted on the thigh connecting part (3), and the thigh connecting part (3) rotates around the pin shaft 2 (2-2); the two push rod telescopic parts (4) are respectively The push rod telescopic member (4) is respectively arranged on the front and rear sides of the fuselage connecting member (1), the connecting end of the push rod telescopic member (4) is connected to the fuselage connecting member (1) through a ball bearing, the extended end of the push rod telescopic member (4) is connected to the thigh connecting member (3) through a ball bearing, and the connection point between the push rod telescopic member (4) and the thigh connecting member (3) and the connection point between the push rod telescopic member (4) and the fuselage connecting member (1) are respectively located on both sides of the second pin (2-2); the axial direction of the output shaft of the hip joint pitch motor (5) is parallel to the x-axis direction, and the output end of the hip joint pitch motor (5) is fixedly connected to the end of the thigh (6), so as to drive the thigh (6) to rotate around the axial direction of the output shaft of the hip joint pitch motor (5); The lower end of the thigh (6) is provided with a notch (6-1) which passes through from front to back, the upper end of the calf (8) is inserted into the notch (6-1) at the lower end of the thigh (6), and the calf (8) and the thigh (6) are respectively mounted on a knee joint connecting shaft (7) arranged along the x-axis direction; a connecting plate (6-3) is respectively arranged on the left and right sides of the middle position of the thigh (6), and the fixed ends of the ankle joint crank rocker drive assembly (12) are mounted on the two connecting plates (6-3); The knee joint crank rocker drive assembly (11) comprises a knee joint pitch motor (11-1), a knee joint crank (11-2) and a knee joint motion connecting rod (11-3); the knee joint pitch motor (11-1) and the hip joint pitch motor (5) are coaxially arranged, the hip joint pitch motor and the knee joint pitch motor are symmetrically arranged on both sides of a mid-plane of the leg structure, the knee joint crank (11-2) is located between the knee joint pitch motor (11-1) and the hip joint pitch motor (5), and the output end of the knee joint pitch motor (11-1) is fixed to one end of the knee joint crank (11-2). The knee joint movement connecting rod (11-3) is fixedly connected, the other end of the knee joint crank (11-2) is hingedly connected to one end of the knee joint movement connecting rod (11-3), and the other end of the knee joint movement connecting rod (11-3) is hingedly connected to the connecting ear at the top of the calf (8); the knee joint movement connecting rod (11-3) comprises a connecting rod 1 and a connecting rod 2, one end of the connecting rod 1 is hingedly connected to the end of the knee joint crank (11-2), the other end of the connecting rod 1 is hingedly connected to one end of the connecting rod 2, and the other end of the connecting rod 2 is hingedly connected to the connecting ear at the top of the calf (8); the end of the connecting rod 2 connected to the calf (8) is bent to achieve the maximum bending degree of the leg; The ankle joint universal joint assembly (9) comprises an ankle joint universal joint (9-1) and an ankle joint mounting seat (9-2); the ankle joint universal joint (9-1) comprises a pin shaft three (9-1-1) in the x-axis direction and a pin shaft four (9-1-2) in the z-axis direction; the lower end of the calf (8) is connected to the two ends of the pin shaft three (9-1-1) and rotates around the pin shaft three (9-1-1); the ankle joint mounting seat (9-2) is fixedly mounted on the instep of the foot (10); the ankle joint universal joint assembly (9-1) comprises an ankle joint universal joint (9-1) and an ankle joint mounting seat (9-2); the ankle joint universal joint assembly (9-1) comprises an ankle joint universal joint (9-1) and an ankle joint mounting seat (9-2); The two ends of a pin shaft four (9-1-2) in the universal joint (9-1) are respectively rotatably mounted on the ankle joint mounting seat (9-2), and the ankle joint mounting seat (9-2) and the foot (10) rotate around the pin shaft four (9-1-2); a connecting shaft (9-2-1) arranged along the x-axis direction is provided on the ankle joint mounting seat (9-2) at a position close to the heel of the foot (10), and the driving end of the knee joint crank rocker driving assembly (11) is rotatably connected to the connecting shaft (9-2-1).

3. The six-degree-of-freedom, low-inertia robot bionic leg according to claim 2, characterized in that: The ankle joint crank rocker drive assembly (12) comprises two ankle joint drive units arranged relatively on both sides of the thigh (6) and the calf (8), each ankle joint drive unit comprises an ankle joint drive motor (12-1), an ankle joint crank (12-2), an ankle joint primary connecting rod (12-3), an ankle joint triangle plate (12-4) and an ankle joint secondary connecting rod (12-5) connected in sequence, the ankle joint drive motor (12-1) is mounted on a connecting plate (6-3) on the side of the thigh (6), one end of the ankle joint crank (12-2) is fixedly connected to the driving end of the ankle joint drive motor (12-1), the other end of the ankle joint crank (12-2) is hingedly connected to one end of the ankle joint primary connecting rod (12-3), and the other end of the ankle joint primary connecting rod (12-3) is hingedly connected to the ankle joint triangle plate (12-4). At the vertex one (12-4-1) of the plate (12-4), the vertex two (12-4-2) of the ankle joint triangular plate (12-4) is hingedly connected to the end of the knee joint connecting shaft (7), the vertex three (12-4-3) of the ankle joint triangular plate (12-4) is hingedly connected to one end of the ankle joint secondary connecting rod (12-5) through a ball bearing, and the other end of the ankle joint secondary connecting rod (12-5) is hingedly connected to the connecting shaft (9-2-1) of the ankle joint mounting seat (9-2) through a ball bearing; wherein the vertex one (12-4-1), the vertex two (12-4-2) and the vertex three (12-4-3) of the ankle joint triangular plate (12-4) are sequentially arranged in a clockwise direction, and the ankle joint primary connecting rod (12-3) and the ankle joint secondary connecting rod (12-5) are respectively located on both sides of the ankle joint triangular plate (12-4).

4. The six-degree-of-freedom, low-inertia robot bionic leg according to claim 3, characterized in that: The push rod telescopic member (4) is an electric cylinder.

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