CN110074905B

CN110074905B - Active ankle joint prosthesis mechanism with connecting rod energy storage and gravity center self-adjustment functions

Info

Publication number: CN110074905B
Application number: CN201910438441.2A
Authority: CN
Inventors: 宋马军; 郭盛; 曲海波; 王向阳; 赵福群
Original assignee: Beijing Jiaotong University
Current assignee: Beijing Jiaotong University
Priority date: 2019-05-24
Filing date: 2019-05-24
Publication date: 2020-10-09
Anticipated expiration: 2039-05-24
Also published as: CN110074905A

Abstract

The invention designs an active ankle joint prosthesis mechanism with connecting rod energy storage and gravity center self-adjustment, and the basic structure comprises a driving motor, a base, a serial spring system of a muscle-like three-loop connecting rod mechanism, a parallel spring system of a muscle-like flexible crank slider mechanism, a pressure sensor, a carbon fiber prosthetic foot, a heel buffer spring system, a gravity center self-adjustment block system, an angle sensor and a driving shaft. The two connecting rod type spring systems can realize continuous energy storage and release, provide energy for the artificial limb mechanism and reduce the working energy consumption of the motor. In addition, the connecting rod mechanism has the advantages of simple structure, easy processing and manufacturing, low production cost and the like. Because the biological joint is a non-uniform geometric body, the plantar flexion-dorsiflexion rotation axis of the ankle joint is not constant, the gravity center self-adjusting block system can realize the function, the self-adjusting function of the gravity center of the human body and the stable posture of the lower limb of the human body is achieved, the bionic motion characteristic of the ankle joint is met, the man-machine comfort degree of an artificial limb wearer is improved, and the service life of the ankle joint artificial limb mechanism is prolonged.

Description

Active ankle joint prosthesis mechanism with connecting rod energy storage and gravity center self-adjustment functions

Technical Field

The invention belongs to the technical field of rehabilitation medical robots, and particularly relates to an active ankle joint prosthesis mechanism with connecting rod energy storage and gravity center self-adjustment functions.

Background

According to the data analysis of the second national disabled person general survey, the number of domestic amputation patients reaches about 2412 thousands of times, and accounts for about one third of the total domestic disabled persons. The artificial limb can compensate the lost limb of the amputee, so the artificial limb still has great market prospect at home and abroad for the research and development and the manufacture of artificial limb mechanisms. However, the existing artificial limbs in the market are all passive type or active passive type, and besides, the development of the ankle joint artificial limb in the domestic market is still the first stage, which is far behind the development of the knee joint artificial limb and the like. Based on this, students have studied the motion mechanism of ankle joint, and have made some structural design and improvement on their prosthetic mechanism, but most of them only consider the passive ankle joint prosthetic mechanism with single motion, and during walking, the mechanism often needs amputees to consume their own metabolic energy. In recent years, with the development of science and technology, students developed intelligent ankle joint prosthesis mechanisms which are still complex though the structures of the mechanisms are improved. Furthermore, the control methods in this mechanism are not mature enough and the cost is high, making inexpensive passive ankle prostheses still popular in the market. Based on the structure, the active ankle joint prosthesis mechanism with the connecting rod energy storage and gravity center self-adjustment functions is designed, and the mechanism is simple and controllable in structure and low in manufacturing cost. The variable-stiffness spring energy storage device based on the novel multi-link mechanism and imitating muscles is introduced, energy storage and energy release operation of the ankle joint prosthesis can be realized in the walking process of an amputation patient, and the ankle joint prosthesis mechanism has a high bionic effect.

Disclosure of Invention

The invention aims to design an active type ankle joint prosthesis mechanism with connecting rod energy storage and gravity center self-adjustment, and solves the problems of low mechanism stability, poor dynamic response, poor adaptability of the ankle joint prosthesis and the external environment in interactive motion, poor human-computer comfort and the like in the active type ankle joint prosthesis mechanism which needs to be solved at present. The mechanism overcomes the defects of technical design structures such as poor lower limb movement posture and gravity center self-adjustment stability of the existing active artificial limb mechanism wearers in the market, enables the design of the ankle joint artificial limb mechanism and the height of the human ankle joint to be simulated, and derives the bionic design of the artificial limb mechanism.

The invention is realized by adopting the following technical scheme:

initiative type ankle joint prosthetic mechanism with connecting rod energy storage and focus self-interacting, its characterized in that: the device comprises a driving motor 1, a base 2, a series spring system 3 of a similar muscle three-loop link mechanism, a parallel spring system 4 of a similar muscle flexible slider-crank mechanism, a pressure sensor 5, a carbon fiber artificial foot 6, a heel buffer spring system 7, a gravity center self-adjusting block system 8, an angle sensor 9 and a driving shaft 10.

The series spring system 3 of the muscle-like three-circuit linkage mechanism comprises: 3-1 parts of a foot seat, 3-2 parts of a small mounting joint, 3-3 parts of a screw rod, 3-4 parts of a cover plate, 3-5 parts of a slider seat, 3-6 parts of an oilless bearing, 3-7 parts of a first pressure spring, 3-8 parts of an adjusting nut, 3-9 parts of a large mounting joint, 3-10 parts of a mounting nut, 3-11 parts of a small hinged seat, 3-12 parts of a large hinged seat, 3-13 parts of a first connecting rod, 3-14 parts of a second connecting rod, 3-15 parts of a third connecting rod, 3-16 parts of a cylindrical barrel, 3-17 parts of a second pressure spring, 3-18 parts;

connection between the parts of the series spring system that make up the muscle-like three-circuit linkage: when the driving motor 1 drives the carbon fiber artificial foot 6 to do flexion and extension movement, the same follow-up movement is carried out with the screw 3-3 arranged on the carbon fiber artificial foot; the screw 3-3 is connected with the small mounting joint 3-2 and the large mounting joint 3-9 through threads, and the small mounting joint 3-2 and the large mounting joint 3-9 form a revolute pair with the foot stool 3-1 and the small hinged support 3-11 respectively; the slider seat 3-5 and the oilless bearing 3-6 are assembled together and form a moving pair with the screw rod 3-3, and the guidance of the slider seat is improved by introducing the oilless bearing 3-6; the foot seat 3-1, the large hinged support 3-12, the piston rod 3-19 and the cylindrical barrel 3-16 form a rotating pair respectively, and the piston rod 3-19 and the cylindrical barrel 3-16 form a moving pair; in the three-loop link mechanism, a first connecting rod 3-13, a second connecting rod 3-14 and a third connecting rod 3-15 form a common rotating pair, and the other end of the common rotating pair respectively forms three rotating pairs with a large hinged support 3-12, a cylindrical barrel 3-16 and a sliding block support 3-5. In addition, the adjusting nuts 3-8 and the adjusting round nuts 3-18 introduced into the spring energy storage mechanism can adjust the rigidity of the spring, and the rigidity characteristic of a spring system is changed to enable the spring system to be suitable for amputees of different types; based on the motion characteristics of the three-loop link mechanism, the serial spring system comprising the first compression spring 3-7 and the second compression spring 3-17 can ensure that the ankle joint prosthetic mechanism can continuously and independently store and release energy when walking, promote the plantar flexion-dorsiflexion motion of the ankle joint and the motion mode switching and reduce the output energy consumption of the motor; because the three-loop link mechanism is a closed link mechanism, the three-loop link mechanism has accurate motion stability and higher dynamic response, and improves the energy utilization efficiency of the prosthetic mechanism.

The parallel spring system 4 of the muscle-like compliant slider-crank mechanism comprises: the flexible rotary hinge comprises, by weight, 4-1 parts of a flexible rotary hinge, 4-2 parts of a virtual driving rod, 4-3 parts of a first mounting seat, 4-4 parts of a connecting rod, 4-5 parts of a second mounting seat, 4-6 parts of a cover plate, 4-7 parts of a sliding block, 4-8 parts of an oilless bearing, 4-9 parts of a pressure spring, 4-10 parts of a regulating round nut, 4-11 parts of a screw rod, 4-12 parts of a nut and 4-13 parts of a third.

The connection between the parts forming the muscle-like soft crank sliding block mechanism is as follows: the first mounting seat 4-3 is fixed on the carbon fiber artificial foot 6 and forms a revolute pair with the connecting rod 4-4; the connecting rod 4-4 and the sliding block 4-7 form a revolute pair; the sliding block 4-7 and the oilless bearing 4-8 are assembled together and form a moving pair with the screw rod 4-11, and the guidance of the sliding block is improved due to the introduction of the oilless bearing 4-8; when the sole of a foot is flat and the toe-off process is carried out, the gravity center of a human body begins to tilt forwards, the carbon fiber artificial foot 6 rotates around the flexible rotating hinge 4-1 and reproduces the stretching motion of the toe joint, the sliding block 4-7 is pushed to slide upwards in an inclined mode, the compression springs 4-9 connected in parallel are compressed to store energy, and energy is provided for the artificial limb mechanism at the toe-off stage; the adjusting round nuts 4-10 can adjust the rigidity characteristic of the pressure springs 4-9, and the rigidity characteristic of the spring system is changed to enable the spring system to be close to the biomechanical characteristic of related muscles, so that the parallel spring system can be suitable for amputees of different types.

Said heel cushioning spring system 7 comprises: the device comprises a foot seat 7-1, a cylindrical barrel 7-2, an adjusting round nut 7-3, a compression spring 7-4 and a piston rod 7-5.

Connections between the parts constituting the heel cushioning spring system: the foot seats 7-1 form rotating pairs with the cylindrical barrel 7-2 and the piston rod 7-5 respectively; the cylindrical barrel 7-2 and the piston rod 7-5 form a moving pair, and the compression and reduction operations of the compression spring are realized through the expansion and contraction of the moving pair, namely the buffering energy storage function when the heel touches the ground and the power assisting function when the heel leaves the ground are realized.

The gravity center self-adjusting block system 8 includes: the device comprises a foot seat 8-1, a centering concave cushion block 8-2, a centering convex block 8-3, a gland plate 8-4 and a high-rigidity pressure spring 8-5.

Connection between the components constituting the system of self-adjusting masses of the centre of gravity: the centering concave cushion block 8-2 and the centering convex block 8-3 are concentrically matched to form a ball-like pair and are assembled with the foot base 8-1; the gland plate 8-4 is arranged on the foot seat 8-1, and limits the large-angle rotation of the centering convex block 8-3 together with the high-rigidity pressure spring 8-5 and keeps a certain corner scope. Because the human bionic joints are all in non-uniform geometric shapes and can be obtained by human anatomy analysis, the rotation axis of the plantar flexion-dorsiflexion of the ankle joints is a non-constant axis, and the small angle self-adjustment of the rotation axis is in order to adapt to the comfort and the stability of the foot and the external environment; when a wearer of the artificial limb mechanism walks on an uneven road, the gravity center self-adjusting block system can enable the wearer to keep a stable state through the posture of the self-adjusting lower limbs according to the change of the space position of the gravity center of the human body, the biological motion characteristics of the ankle joint are met, the man-machine comfort between the wearer and the ankle joint artificial limb mechanism during walking is improved, and the service life of the ankle joint artificial limb mechanism is prolonged.

Compared with the prior art, the invention has the following beneficial effects: (1) a three-loop link mechanism is introduced into the series spring energy storage system, so that a single-input and multi-output function is realized. The multi-output mode can respectively provide required energy for the ankle joint prosthesis in the plantar flexion-dorsiflexion movement, the output of motor energy is reduced, and in addition, the three-loop connecting rod mechanism has better movement characteristics and movement stability. (2) A flexible crank slider mechanism is introduced into the parallel spring energy storage system, when the toes are kicked off, the rotation between the toes and the soles is realized by a flexible hinge, and the movement is completely adapted to the movement of the toes of a human body. The introduction of the parallel spring energy storage system realizes a continuous and stable energy storage and release mode for the ankle joint prosthesis in continuous gait, and accords with energy supply during motion of the ankle joint of a human body. (3) Because the biological joints are all in non-uniform geometric shapes, the flexion-extension rotation axis of the ankle joint is a non-constant axis by anatomical analysis. The introduction of the gravity center self-adjusting block system can realize the characteristic of high self-adjustment of the plantar flexion-dorsiflexion rotation axis of the ankle joint prosthesis and the gravity center of a human body, keep the relative stress direction of the ankle and the moment to the gravity center unchanged, and is favorable for prolonging the service life of the prosthesis mechanism. In addition, the link mechanism has relatively simple kinematics and good dynamic response, is easy to produce, machine and manufacture, and can provide important reference for the design of other joint prosthesis mechanisms and even the design of precise mechanisms.

Drawings

FIG. 1 is a block diagram of a modular construction of an active ankle joint prosthesis with link energy storage and center of gravity self-adjustment and a center of gravity self-adjustment block system;

FIG. 2 is a schematic diagram of a series spring system of the three-circuit linkage mechanism of the muscle class;

FIG. 3 is a model diagram of a parallel spring system structure of a muscle-like compliant slider-crank mechanism;

FIG. 4 is a diagram of a model of a heel cushioning spring system;

in the figure: the device comprises a driving motor (1), a base (2), a series spring system (3) of a similar muscle three-loop link mechanism, a parallel spring system (4) of a similar muscle flexible crank sliding block mechanism, a pressure sensor (5), a carbon fiber artificial foot (6), a heel buffer spring system (7), a gravity center self-adjusting block system (8), an angle sensor (9) and a driving shaft (10). A series spring system (3) of a muscle-like three-circuit linkage mechanism comprising: the device comprises a footstand (3-1), a small mounting joint (3-2), a screw rod (3-3), a cover plate (3-4), a slider seat (3-5), an oilless bearing (3-6), a first pressure spring (3-7), an adjusting nut (3-8), a large mounting joint (3-9), a mounting nut (3-10), a small hinged support (3-11), a large hinged support (3-12), a first connecting rod (3-13), a second connecting rod (3-14), a third connecting rod (3-15), a cylindrical barrel (3-16), a second pressure spring (3-17), an adjusting round nut (3-18) and a piston rod (3-19); the parallel spring system (4) of the muscle-like compliant slider-crank mechanism comprises: the flexible rotary hinge comprises a flexible rotary hinge (4-1), a virtual driving rod (4-2), a first mounting seat (4-3), a connecting rod (4-4), a second mounting seat (4-5), a cover plate (4-6), a sliding block (4-7), an oilless bearing (4-8), a pressure spring (4-9), an adjusting round nut (4-10), a screw rod (4-11), a nut (4-12) and a third mounting seat (4-13). The heel cushioning spring system (7) comprises: the device comprises a foot seat (7-1), a cylindrical barrel (7-2), an adjusting round nut (7-3), a compression spring (7-4) and a piston rod (7-5); the center of gravity self-adjusting block system (8) comprises: the device comprises a foot seat (8-1), a centering concave cushion block (8-2), a centering convex block (8-3), a gland plate (8-4) and a high-rigidity pressure spring (8-5).

Detailed Description

For a further understanding of the active ankle joint prosthesis mechanism with link energy storage and center of gravity self-adjustment provided by the present invention, reference will now be made in detail to the embodiments illustrated in the drawings.

Fig. 1 is a model diagram of a structure of an active type ankle joint prosthesis mechanism with connecting rod energy storage and gravity center self-adjustment, which is provided by the invention, and the basic structure of the active type ankle joint prosthesis mechanism comprises a driving motor 1, a base 2, a series spring system 3 of a muscle-like three-loop connecting rod mechanism, a parallel spring system 4 of a muscle-like flexible crank slider mechanism, a pressure sensor 5, a carbon fiber artificial foot 6, a heel buffer spring system 7, a gravity center self-adjustment block system 8, an angle sensor 9 and a driving shaft 10. The ankle joint artificial limb mechanism can realize the functions of plantarflexion and dorsiflexion, and meanwhile, a series-parallel spring system is introduced, so that certain energy supplement can be provided for the continuous motion of the mechanism, the output of motor energy is reduced, the design cost of the ankle joint artificial limb mechanism is reduced, and the like. The gravity center self-adjusting block system 8 comprises a foot seat 8-1, a centering concave cushion block 8-2, a centering convex block 8-3, a gland plate 8-4 and a high-rigidity pressure spring 8-5. The centering concave cushion block 8-2 and the centering convex block 8-3 are concentrically matched to form a ball-like pair and are assembled with the foot base 8-1; the gland plate 8-4 is arranged on the foot seat 8-1, and limits the large-angle rotation of the centering convex block 8-3 together with the high-rigidity pressure spring 8-5 and keeps a certain corner scope. Because the biological joints are all in non-uniform geometric shapes, the plantar flexion-dorsiflexion rotation axis of the biological joints can be obtained as a non-constant axis through anatomical analysis of the ankle joints, and on the basis, the rotation axis of flexion and extension movement of the ankle joints is enabled to perform small-angle self-adjustment along with the change of the gravity center position of a human body through the introduction of the system, so that the biological motion characteristics of the ankle joints are met.

FIG. 2 is a model diagram of a serial spring system structure of a muscle-like three-circuit link mechanism provided by the invention, which comprises a foot seat 3-1, a small mounting joint 3-2, a screw rod 3-3, a cover plate 3-4, a slider seat 3-5, an oilless bearing 3-6, a pressure spring I3-7, an adjusting nut 3-8, a large mounting joint 3-9, a mounting nut 3-10, a small hinged support 3-11, a large hinged support 3-12, a connecting rod I3-13, a connecting rod II 3-14, a connecting rod III 3-15, a cylindrical barrel 3-16, a pressure spring II 3-17, an adjusting round nut 3-18 and a piston rod 3-19; when the driving motor 1 drives the carbon fiber artificial foot 6 to do flexion and extension movement, the same follow-up movement is carried out with the screw 3-3 arranged on the carbon fiber artificial foot; the screw 3-3 is connected with the small mounting joint 3-2 and the large mounting joint 3-9 through threads, and the small mounting joint 3-2 and the large mounting joint 3-9 form a revolute pair with the foot stool 3-1 and the small hinged support 3-11 respectively; the slider seat 3-5 and the oilless bearing 3-6 are assembled together and form a moving pair with the screw rod 3-8, and the guidance of the slider seat is improved by introducing the oilless bearing 3-6; the foot seat 3-1, the large hinged support 3-12, the piston rod 3-19 and the cylindrical barrel 3-16 form a rotating pair respectively, and the piston rod 3-19 and the cylindrical barrel 3-16 form a moving pair; in the three-loop link mechanism, a first connecting rod 3-13, a second connecting rod 3-14 and a third connecting rod 3-15 form a common rotating pair, and the other end of the common rotating pair respectively forms three rotating pairs with a large hinged support 3-12, a cylindrical barrel 3-16 and a sliding block support 3-5. In addition, the adjusting nuts 3-8 and the adjusting round nuts 3-18 introduced into the spring energy storage mechanism can adjust the rigidity of the spring, and the rigidity characteristic of the spring system is changed to be close to the biomechanical characteristic of related muscles.

FIG. 3 is a structural model diagram of a parallel spring system of the muscle-like compliant crank-slider mechanism provided by the invention, and the parallel spring system comprises a flexible rotating hinge 4-1, a virtual active rod 4-2, a first mounting seat 4-3, a connecting rod 4-4, a second mounting seat 4-5, a cover plate 4-6, a slider 4-7, an oilless bearing 4-8, a pressure spring 4-9, an adjusting round nut 4-10, a screw rod 4-11, a nut 4-12 and a third mounting seat 4-13. The first mounting seat 4-3 is fixed on the carbon fiber artificial foot 6 and forms a revolute pair with the connecting rod 4-4; the connecting rod 4-4 and the sliding block 4-7 form a revolute pair; the sliding block 4-7 and the oilless bearing 4-8 are assembled together and form a moving pair with the screw rod 4-11, and the guidance of the sliding block is improved due to the introduction of the oilless bearing 4-8; when the sole of the foot is in the process of being flat to toe off, the carbon fiber artificial foot 6 rotates on the flexible rotating hinge 4-1, so that the sliding block 4-7 is driven to slide upwards in an inclined mode. In addition, the spring stiffness can be adjusted by adjusting the round nuts 4-10, and the stiffness characteristic of the spring system can be changed to be close to the biomechanical characteristic of related muscles.

FIG. 4 is a schematic diagram of a structural model of the heel cushioning spring system provided by the invention, which comprises a foot seat 7-1, a cylindrical barrel 7-2, an adjusting round nut 7-3, a compression spring 7-4 and a piston rod 7-5. The foot seats 7-1 form rotating pairs with the cylindrical barrel 7-2 and the piston rod 7-5 respectively; the cylindrical barrel 7-2 and the piston rod 7-5 form a moving pair, and the compression and reduction operations of the compression spring are realized through the expansion and contraction of the moving pair, namely the buffering energy storage function when the heel touches the ground and the power assisting function when the heel leaves the ground are realized.

According to the active ankle joint prosthesis mechanism with the connecting rod energy storage and gravity center self-adjustment functions, when the carbon fiber prosthetic foot 6 and the foot base 8-1 are driven to rotate by the driving motor 1, the spring energy storage system in the ankle joint prosthesis mechanism can perform corresponding operation of storing and releasing energy in a moving mode. When the ankle joint prosthetic mechanism performs dorsiflexion movement, the carbon fiber prosthetic foot 6 drives the piston rods 3-19 to push upwards, so that the second pressure springs 3-17 compress and store energy, and the energy is released when the ankle joint prosthetic mechanism recovers to the original position, thereby reducing the output of electric energy. When the ankle joint prosthesis mechanism performs plantarflexion movement, the carbon fiber prosthesis foot 6 drives the sliding block seats 3-5 to push upwards, so that the compression springs 3-7 compress and store energy, and when the ankle joint prosthesis mechanism recovers to the original position, the energy is released, and the output of electric energy is reduced. When the toes rotate to carry out the stage of leaving the ground, the compression springs 4-9 in the parallel spring system are compressed by the slide blocks 4-7 to provide large energy required for pedaling the legs to leave the ground, and the energy storage and release of the compression springs one 3-7 are also involved in the stage. Because the biological joints are all in non-uniform geometric shapes, the plantar flexion-dorsiflexion rotation axis of the biological joints can be obtained as a non-constant axis through anatomical analysis of the ankle joints, the gravity center self-adjusting block system has the self-adjusting function of the plantar flexion-dorsiflexion rotation axis of the ankle joints along with the change of the gravity center position of a human body, the biological motion characteristics of the ankle joints are met, the man-machine comfort degree and the stability of a wearer of the ankle joint artificial limb mechanism in the walking process are improved, and the service life of the ankle joint artificial limb mechanism is prolonged.

Claims

1. An active ankle joint prosthesis mechanism with link energy storage and self-adjustment of the center of gravity, the basic mechanism comprising: the ankle joint artificial limb mechanism comprises a driving motor (1), a base (2), a series spring system (3) of a muscle-like three-loop link mechanism, a parallel spring system (4) of a muscle-like flexible crank slider mechanism, a pressure sensor (5), a carbon fiber artificial foot (6), a heel buffer spring system (7), a gravity center self-adjusting block system (8), an angle sensor (9) and a driving shaft (10), wherein the ankle joint artificial limb mechanism has single rotational freedom degree and can recover the ankle joint plantar flexion-dorsiflexion motion capability lost by an amputation patient;

the series spring system of the muscle-like three-loop link mechanism comprises a foot seat (3-1), a small mounting joint (3-2), a screw rod (3-3), a cover plate (3-4), a slider seat (3-5), an oilless bearing (3-6), a first pressure spring (3-7), an adjusting nut (3-8), a large mounting joint (3-9), a mounting nut (3-10), a small hinged support (3-11), a large hinged support (3-12), a first connecting rod (3-13), a second connecting rod (3-14), a third connecting rod (3-15), a cylindrical barrel (3-16), a second pressure spring (3-17), an adjusting round nut (3-18) and a piston rod (3-19);

in the series spring system of the muscle-like three-circuit link mechanism, the parts are connected with each other: the screw rod (3-3) is connected with the small mounting joint (3-2) and the large mounting joint (3-9) through threads, the small mounting joint (3-2) and the large mounting joint (3-9) respectively form a rotating pair with the foot seat (3-1) and the small hinged seat (3-11), the slider seat (3-5) is assembled with the oilless bearing (3-6) and forms a moving pair with the screw rod (3-3), the introduction of the oilless bearing (3-6) improves the guidance of the slider seat, the foot seat (3-1) and the large hinged seat (3-12) respectively form a rotating pair with the piston rod (3-19) and the cylindrical barrel (3-16), the piston rod (3-19) and the cylindrical barrel (3-16) form a moving pair, and the connecting rod I (3-13) and the connecting rod II in the three-loop connecting rod mechanism, The second connecting rod (3-14) and the third connecting rod (3-15) form a common revolute pair, the other end of the common revolute pair respectively forms three revolute pairs with the large hinged support (3-12), the cylindrical barrel (3-16) and the sliding block seat (3-5), and the adjusting nuts (3-8) and the adjusting round nuts (3-18) are introduced into a series spring system of the muscle-like three-loop connecting rod mechanism to adjust the rigidity of the spring, so that the rigidity characteristic of the spring system is changed to enable the spring system to be suitable for amputees of different types; based on the motion characteristics of the three-loop link mechanism, the serial spring system comprising the first compression spring (3-7) and the second compression spring (3-17) can ensure that the ankle joint prosthetic mechanism can continuously and independently store and release energy when walking, promote the plantar flexion-dorsiflexion motion of the ankle joint, switch motion modes and reduce the output energy consumption of the motor; because the three-loop link mechanism is a closed link mechanism, the three-loop link mechanism has accurate motion stability and higher dynamic response, and improves the energy utilization efficiency of the prosthetic mechanism;

the parallel spring system of the muscle-like soft crank sliding block mechanism comprises a flexible rotary hinge (4-1), a virtual driving rod (4-2), a first mounting seat (4-3), a connecting rod (4-4), a second mounting seat (4-5), a cover plate (4-6), a sliding block (4-7), an oilless bearing (4-8), a pressure spring (4-9), an adjusting round nut (4-10), a screw rod (4-11), a nut (4-12) and a third mounting seat (4-13);

the muscle-like flexible crank-slider mechanism is characterized in that the parts are connected with each other: the first mounting seat (4-3) is fixed on a carbon fiber prosthetic foot (6) and forms a revolute pair with the connecting rod (4-4), the connecting rod (4-4) and the sliding block (4-7) form a revolute pair, the sliding block (4-7) and the oilless bearing (4-8) are assembled together and form a moving pair with the screw rod (4-11), the guidance of the sliding block is improved due to the introduction of the oilless bearing (4-8), when the sole is flat and the toes leave the ground, the gravity center of a human body begins to tilt forwards, the carbon fiber prosthetic foot (6) rotates around the flexible rotating hinge (4-1) and reproduces the stretching motion of the toes, the sliding block (4-7) is pushed to slide upwards in an inclined mode, the compression springs (4-9) connected in parallel are compressed, energy is stored, and energy is provided for the prosthetic mechanism at the toe; the adjusting round nuts (4-10) can adjust the rigidity characteristics of the pressure springs (4-9), and the rigidity characteristics of the spring system are changed to be close to the biomechanical characteristics of related muscles, so that the parallel spring system can be suitable for amputees of different types.

2. The active ankle joint prosthesis mechanism with link energy storage and center of gravity self-adjustment according to claim 1, wherein: the gravity center self-adjusting block system comprises a foot seat (8-1), a centering concave cushion block (8-2), a centering convex block (8-3), a gland plate (8-4) and a high-rigidity pressure spring (8-5);

the gravity center self-adjusting block system is characterized in that the parts are connected with each other: the centering concave cushion block (8-2) and the centering convex block (8-3) are concentrically matched to form a ball-like pair and are assembled with the foot seat (8-1), and the gland plate (8-4) is installed on the foot seat (8-1) and limits the large-angle rotation of the centering convex block (8-3) together with the high-rigidity pressure spring (8-5) and keeps a certain corner margin; because the human bionic joints are all in non-uniform geometric shapes and can be obtained by human anatomy analysis, the rotation axis of the plantar flexion-dorsiflexion of the ankle joints is a non-constant axis, and the small angle self-adjustment of the rotation axis is in order to adapt to the comfort and the stability of the foot and the external environment; when a wearer of the artificial limb mechanism walks on an uneven road, the gravity center self-adjusting block system can enable the wearer to keep a stable state through the posture of the self-adjusting lower limbs according to the change of the space position of the gravity center of the human body, the biological motion characteristics of the ankle joint are met, the man-machine comfort between the wearer and the ankle joint artificial limb mechanism during walking is improved, and the service life of the ankle joint artificial limb mechanism is prolonged.