A two-degree-of-freedom parallel-driven humanoid ankle joint mechanism

Abstract

A two-degree-of-freedom parallel-driven humanoid ankle mechanism relates to the technical field of ankle joints of bipedal humanoid robots. The present invention solves the problems of insufficient driving force, low rigidity, and lack of perception in existing robot ankle joints, and also solves the problems of complex and bulky structure caused by the complex structure of multi-degree-of-freedom humanoid leg ankle joints. The piston rods in the two groups of ankle joint piston assemblies of the present invention are respectively hinged to the head ends of the two ankle joint two-force rods through two two-force rod connecting hinges, and the ends of the two ankle joint two-force rods are respectively hinged to the two two-force rod shaft seats through two two-force rod cross-axis hinges, and the bottom of the calf skeleton is hinged to the ankle joint shaft seat through the ankle cross-axis hinge. When the two groups of hydraulic cylinders push the two groups of piston rods to move synchronously, the humanoid foot realizes pitch direction rotation, and when the two groups of hydraulic cylinders push the two groups of piston rods to move asynchronously, the humanoid foot realizes side swing direction rotation. The present invention can provide driving torque in multiples, and has the advantages of high rigidity and large load.

Description

Technical Field

[0001] The invention relates to the technical field of ankle joints of bipedal humanoid robots, and in particular to a two-degree-of-freedom parallel-driven humanoid ankle joint mechanism. Background Art

[0002] Nowadays, bipedal humanoid robots have unparalleled advantages over other robots in terms of movement flexibility and environmental adaptability. The ankle joint is an important part of the lower limb movement system of bipedal robots. In view of the excellent characteristics of human ankle joints, it is necessary to adopt bionics to design the ankle joint mechanism of robots. Humanoid robots have the advantages of both humans and machines in terms of structure and performance, can adapt to extreme environments, and have human intelligence and adaptability.

[0003] The traditional bipedal robot ankle joint adopts a serial mechanism, which has the advantages of simple structure, low cost, and simple control, but it is insufficiently powered, has low stiffness, and high inertia, and cannot adapt to large loads and rapid control requirements. Therefore, it is gradually replaced by humanoid parallel ankle joints with better performance. The parallel mechanism has the advantages of high stiffness, strong load-bearing capacity, high precision, and low inertia of the end parts. It has obvious advantages over the serial mechanism in high-speed and large-load-bearing situations. However, the existing parallel ankle mechanism has a complex structure, large size, and is not flexible enough, and lacks effective space to install various sensors.

[0004] At present, there are three main driving modes for robots: electric drive, pneumatic drive and hydraulic drive. Electric drive has a simple structure, convenient control and fast control response, but it has high requirements for use conditions, small torque, easy to stall and low load capacity. Pneumatic drive has convenient energy storage, easy to obtain raw materials, flame retardant and pollution-free, but its working pressure is low, output load is small, and the movement is unstable, the precision is low, and it is easily affected by load changes. Hydraulic drive has a high torque / volume ratio and strong anti-stall and anti-impact capabilities, large load capacity and fast response; but the hydraulic structure is complex, there are many external oil pipes, and the control is complex.

[0005] In summary, the existing robot ankle joints have problems such as insufficient driving force, low stiffness, and no perception. There are also problems such as complex and bulky structure caused by the complex structure of the multi-degree-of-freedom humanoid leg ankle joint. Summary of the invention

[0006] The purpose of the present invention is to solve the problems of insufficient driving force, low rigidity and lack of perception in the existing robot ankle joints, as well as the problems of complex and bulky structure caused by the complex structure of the multi-degree-of-freedom humanoid leg ankle joint, and thus provide a two-degree-of-freedom parallel drive humanoid ankle joint mechanism.

[0007] The technical solution of the present invention is:

[0008] A two-degree-of-freedom parallel-driven humanoid ankle joint mechanism, comprising a humanoid foot 1, an ankle joint base 2, a calf skeleton 7, an ankle joint cross-axis hinge, two groups of hydraulic cylinders, two groups of ankle joint piston assemblies, two ankle joint two-force rods 5, two two-force rod connecting hinges and two two-force rod cross-axis hinges. The main body of the calf skeleton 7 comprises two hollow side plates arranged opposite to each other and two groups of hydraulic cylinders arranged in parallel between the two hollow side plates along the length direction of the calf skeleton 7. The two groups of hydraulic cylinders are integrally formed with the calf skeleton 7. The two ends of the ankle joint two-force rod 5 are processed into a fork-like structure. The two ankle joint two-force rods 5 are arranged in parallel directly below the two groups of hydraulic cylinders. A humanoid foot 1 is arranged directly below the calf skeleton 7. An ankle joint base 2 is installed at the top of the humanoid foot 1. The ankle joint base 2 comprises a base plate 20, an ankle joint shaft seat 21 and two two-force rod shaft seats 22. The middle of the upper end surface of the base plate 20 An ankle joint shaft seat 21 is installed on the rear side of the foot, and two two-force rod shaft seats 22 are symmetrically arranged on both sides in front of the ankle joint shaft seat 21 with the midline of the length direction of the base plate 20 as the center. The bottom ends of the two two-force rod shaft seats 22 are fixedly connected to the base plate 20, and two groups of ankle joint piston assemblies are respectively installed on the two groups of hydraulic cylinders. The piston rods in the two groups of ankle joint piston assemblies are respectively hinged to the fork-like structures at the head ends of the two ankle joint two-force rods 5 through two two-force rod connecting hinges, and the fork-like structures at the ends of the two ankle joint two-force rods 5 are respectively hinged to the two two-force rod shaft seats 22 through two two-force rod cross-axis hinges, and the bottom of the calf skeleton 7 is hinged to the ankle joint shaft seat 21 through the ankle cross-axis hinge. When the two groups of hydraulic cylinders push the two groups of piston rods to move synchronously, the anthropomorphic foot 1 realizes rotation in the pitch direction, and when the two groups of hydraulic cylinders push the two groups of piston rods to move asynchronously, the anthropomorphic foot 1 realizes rotation in the side swing direction.

[0009] Furthermore, it also includes a linear guide rail 14 and a linear guide rail 2 15. The linear guide rail 14 and the linear guide rail 2 15 are arranged in parallel along the length direction of the calf frame 7 and are respectively located directly below the two groups of hydraulic cylinders. The linear guide rail 14 and the linear guide rail 2 15 are fixedly connected to the calf frame 7.

[0010] Furthermore, the ankle joint piston assembly includes a piston rod, a slider 13, and a slider connector 6. One end of the piston rod is placed inside the hydraulic cylinder, and the other end of the piston rod is fixedly connected to the slider 13 through the slider connector 6. The slider 13 is slidably connected to the linear guide rail 14 and / or the linear guide rail 2 15.

[0011] Furthermore, the two-force rod connecting hinge includes a two-force rod shaft 18 and a radial spherical bearing 19. The end of the piston rod is processed into a circular ring structure, and the radial spherical bearing 19 is installed in the inner hole of the circular ring structure. The middle part of the two-force rod shaft 18 is inserted into the radial spherical bearing 19. An axial hole is processed on the fork-shaped structure at the head end of the ankle joint two-force rod 5, and the two ends of the two-force rod shaft 18 are rotatably connected to the fork-shaped structure at the head end of the ankle joint two-force rod 5.

[0012] Furthermore, the two-force rod cross-axis hinge includes a two-force rod shaft 3 and a two-force rod cross-axis sleeve 4. The two-force rod cross-axis sleeve 4 is rotatably connected to the fork-shaped structure at the end of the ankle joint two-force rod 5 through the shafts at both ends. The middle part of the two-force rod shaft 3 is inserted into the middle shaft sleeve of the two-force rod cross-axis sleeve 4, and the two ends of the two-force rod shaft 3 are rotatably connected to the corresponding two-force rod shaft seats 22.

[0013] Furthermore, the ankle cross-axis hinge includes an ankle shaft 17 and an ankle cross-axis sleeve 16. The bottom of the two hollow side panels of the calf skeleton 7 are both processed with axis holes. The ankle cross-axis sleeve 16 is rotatably connected to the bottom of the two hollow side panels through axis rods at both ends. The middle part of the ankle shaft 17 is inserted into the ankle cross-axis sleeve 16, and the two ends of the ankle shaft 17 are rotatably connected to the ankle shaft seat 21.

[0014] Furthermore, it also includes a rodless chamber oil pressure sensor 9, a servo valve 10 and a rod chamber oil pressure sensor 11. The rodless chamber oil pressure sensor 9, the servo valve 10 and the rod chamber oil pressure sensor 11 are all located on the rear side of the calf frame 7. The servo valve 10 is installed on the hydraulic cylinder. The servo valve 10 is connected to the rod chamber and the rodless chamber of the hydraulic cylinder through a hydraulic oil circuit integrally formed with the hydraulic cylinder. The pressure measuring probe of the rodless chamber oil pressure sensor 9 is inserted into the rodless chamber of the hydraulic cylinder, and the pressure measuring probe of the rod chamber oil pressure sensor 11 is inserted into the rod chamber of the hydraulic cylinder.

[0015] Furthermore, it also includes a displacement sensor, which is installed inside the hydraulic cylinder.

[0016] Furthermore, it also includes a shock-absorbing knee 8, which is installed at the upper front end of the calf frame 7.

[0017] Furthermore, it also includes a hydraulic controller 12 , which is installed at the rear end of the upper middle part of the calf frame 7 , and is connected to the servo valve 10 .

[0018] Compared with the prior art, the present invention has the following effects:

[0019] Compared with various existing robot ankle joints, the two-degree-of-freedom parallel-driven humanoid ankle joint mechanism of the present invention has the following beneficial effects:

[0020] 1. The two-degree-of-freedom parallel-driven anthropomorphic ankle joint mechanism of the present invention can realize front and rear pitching and left and right rolling movements, flexibly adjust the posture, and have a large movement angle space. The ankle joint is driven by two parallel hydraulic cylinders. When the two sets of hydraulic cylinders push the two sets of piston rods to move synchronously, the anthropomorphic foot 1 realizes pitching rotation. When the two sets of hydraulic cylinders push the two sets of piston rods to move asynchronously, the anthropomorphic foot 1 realizes sideways rotation. This realizes the adjustment of the center of gravity and posture of the robot during walking, running and jumping.

[0021] 2. The present invention adopts 2PSU&U parallel mechanism, which has flexible two-degree-of-freedom movement, stable structure, simple and reliable, neat appearance, simple control, and the parallel-driven ankle joint can provide multiple driving torque under the same oil supply pressure, and has the advantages of high rigidity and large load.

[0022] 3. The present invention adopts a hydraulic drive system, which has a high torque / volume ratio and strong anti-stalling ability, and can withstand a large load. The hydraulic system and the skeleton are integrated with the topological design, and the hydraulic cylinder, the oil circuit and the skeleton are integrated through the topological optimization design, which effectively overcomes the shortcomings of the traditional hydraulic system with complex structure, more external oil pipes and heavy weight, and the system reliability and airtightness are greatly improved.

[0023] 4. The present invention adopts integrated skeleton 3D printing processing, which is convenient for processing, simple in structure, and easy to install and disassemble, making the whole machine compact and lightweight.

[0024] 5. The present invention adopts a servo valve, an oil pressure sensor and a displacement sensor, and a servo closed-loop control, which can sense the state of the ankle joint in real time and control and adjust the oil pressure and flow, thereby achieving precise control, convenient control, and ensuring position accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a front view of the two-degree-of-freedom parallel-driven humanoid ankle joint mechanism of the present invention;

[0026] Figure 2 It is a left view of the two-degree-of-freedom parallel-driven humanoid ankle joint mechanism of the present invention;

[0027] Figure 3 It is a right side view of the two-degree-of-freedom parallel-driven humanoid ankle joint mechanism of the present invention;

[0028] Figure 4 It is a rear view of the two-degree-of-freedom parallel-driven humanoid ankle joint mechanism of the present invention;

[0029] Figure 5 yes Figure 1 Sectional view at AA;

[0030] Figure 6 is a top view of the two-degree-of-freedom parallel-driven humanoid ankle joint mechanism of the present invention;

[0031] Figure 7 It is an exploded view of the two-degree-of-freedom parallel-driven humanoid ankle joint mechanism of the present invention;

[0032] Figure 8 It is a front view of the ankle joint of the present invention in a pitching motion state (simulating a human foot with toes touching the ground);

[0033] Fig. 9It is a left view of the ankle joint of the present invention in a pitching motion state (simulating a human foot with the toes touching the ground);

[0034] Fig.10 It is a rear view of the ankle joint of the present invention in a pitching motion state (simulating a human foot with the toes touching the ground);

[0035] Fig.11 It is a right view of the ankle joint of the present invention in a pitching motion state (simulating a human foot with the toes touching the ground);

[0036] Fig.12 It is a right view of the ankle joint of the present invention in a pitching motion state (simulating a human foot with the heel touching the ground);

[0037] Fig.13 It is a left view of the ankle joint of the present invention in a pitching motion state (simulating a human foot with the heel touching the ground);

[0038] Fig.14 It is a left view of the ankle joint of the present invention in a pitching motion state (simulating a human foot with the heel touching the ground);

[0039] Fig.15 It is a rear view of the ankle joint of the present invention in a pitching motion state (simulating a human foot with the heel touching the ground);

[0040] Fig.16 It is a left view of the ankle joint of the present invention in a rolling motion state (simulating a human foot surface rolling to the left);

[0041] Fig.17 It is a rear view of the ankle joint of the present invention in a rolling motion state (simulating a human foot with the instep rolling to the left);

[0042] Fig.18 It is a right view of the ankle joint of the present invention in a rolling motion state (simulating a human foot surface rolling to the left);

[0043] Fig.19 It is a front view of the ankle joint of the present invention in a rolling motion state (simulating a human foot surface rolling to the left);

[0044] Fig. 20 It is a left view of the ankle joint of the present invention in a rolling motion state (simulating a human foot surface rolling to the right);

[0045] Fig.21 It is a front view of the ankle joint of the present invention in a rolling motion state (simulating a human foot surface rolling to the right);

[0046] Fig. 22 It is a right view of the ankle joint of the present invention in a rolling motion state (simulating a human foot surface rolling to the right);

[0047] Fig.23 It is a rear view of the ankle joint of the present invention in a state of transverse rolling motion (simulating a human foot surface rolling to the right).

[0048] In the figure: 1-humanoid foot; 2-ankle joint base; 3-two-force rod axis 2; 4-two-force rod cross shaft sleeve; 5-ankle joint two-force rod; 6-slider connector; 7-calf skeleton; 8-shock-absorbing knee; 9-rodless chamber oil pressure sensor; 10-servo valve; 11-rod chamber oil pressure sensor; 12-hydraulic controller; 13-slider; 14-linear guide 1; 15-linear guide 2; 16-ankle joint cross shaft sleeve; 17-ankle joint axis; 18-two-force rod axis 1; 19-radial spherical bearing; 20-base plate; 21-ankle joint shaft seat; 22-two-force rod shaft seat. DETAILED DESCRIPTION

[0049] Specific implementation method 1: Combination Figures 1 to 23 The present embodiment is described. A two-degree-of-freedom parallel-driven humanoid ankle joint mechanism of the present embodiment comprises a humanoid foot 1, an ankle joint base 2, a calf skeleton 7, an ankle joint cross-axis hinge, two groups of hydraulic cylinders, two groups of ankle joint piston assemblies, two ankle joint two-force rods 5, two two-force rod connecting hinges and two two-force rod cross-axis hinges. The main body of the calf skeleton 7 comprises two hollow side panels arranged opposite to each other and two groups of hydraulic cylinders arranged in parallel between the two hollow side panels along the length direction of the calf skeleton 7. The two groups of hydraulic cylinders are integrally formed with the calf skeleton 7. The two ends of the ankle joint two-force rod 5 are processed into a fork-like structure. The two ankle joint two-force rods 5 are arranged in parallel directly below the two groups of hydraulic cylinders. A humanoid foot 1 is provided directly below the calf skeleton 7. An ankle joint base 2 is installed at the top of the humanoid foot 1. The ankle joint base 2 comprises a base plate 20, an ankle joint shaft seat 21 and two two-force rod shaft seats 22. The base An ankle joint shaft seat 21 is installed on the rear side of the middle part of the upper end surface of the plate 20, and two two-force rod shaft seats 22 are symmetrically arranged on both sides in front of the ankle joint shaft seat 21 with the midline of the length direction of the base plate 20 as the center. The bottom ends of the two two-force rod shaft seats 22 are fixedly connected to the base plate 20, and two groups of ankle joint piston assemblies are respectively installed on the two groups of hydraulic cylinders. The piston rods in the two groups of ankle joint piston assemblies are respectively hinged to the fork-like structures at the head ends of the two ankle joint two-force rods 5 through two two-force rod connecting hinges, and the fork-like structures at the ends of the two ankle joint two-force rods 5 are respectively hinged to the two two-force rod shaft seats 22 through two two-force rod cross-axis hinges, and the bottom of the calf skeleton 7 is hinged to the ankle joint shaft seat 21 through the ankle cross-axis hinge. When the two groups of hydraulic cylinders push the two groups of piston rods to move synchronously, the anthropomorphic foot 1 realizes rotation in the pitch direction, and when the two groups of hydraulic cylinders push the two groups of piston rods to move asynchronously, the anthropomorphic foot 1 realizes rotation in the side swing direction.

[0050] In this embodiment, the design of the calf skeleton 7 adopts topology optimization for weight reduction and surface modeling reconstruction. Theory and practice show that after topology optimization, compared with the original structure, the skeleton effectively reduces the mass and the inertia of the ankle joint and calf, making the ankle joint easier to control, and the bipedal robot walks, runs and jumps more flexibly, accurately and quickly.

[0051] In this embodiment, the calf skeleton 7 is subjected to finite element analysis to effectively improve the skeleton stiffness and stability, and can play a role of constraint feedback in the entire skeleton optimization design process. After continuous iteration under the constraints of force and design space, the structure of the skeleton surface model is determined.

[0052] In this embodiment, the calf frame 7 and its hydraulic cylinder oil circuit are made of 3D printing technology and titanium alloy high-performance metal. After printing, shot peening is used on the frame body to improve the surface performance, and then fine processing is performed to complete the processing of various planes and holes, eliminating the process oil circuit and minimizing the occupied space and weight. Oil holes are reserved on both sides of the hydraulic cylinder for connecting with the oil-flowing joints to facilitate the input of oil.

[0053] In this embodiment, the dual hydraulic cylinder is located between the two hollow side panels of the calf frame 7, the ankle joint piston assembly is located at the front of the calf frame 7, and the oil pressure sensor and servo valve are installed at the rear of the calf frame 7. The staggered arrangement of the two can effectively avoid motion interference and make the ankle joint structure compact and delicate.

[0054] In this embodiment, the ankle joint base 2 and the humanoid foot 1 are designed as separate parts, which is convenient for quick assembly and replacement of the foot plate, improves the overall structural stability of the ankle joint interface, improves the reliability of the system, and has the characteristics of easy installation.

[0055] In this embodiment, all sensors and drive controllers are integrated in the back of the calf and communicate via the CAN bus, which has the characteristics of simple power supply and communication interface and easy use.

[0056] In this embodiment, in order to achieve movement in both pitch and roll directions while taking into account the design appearance of the calf, two sets of hydraulic cylinders are driven in parallel. The hydraulic cylinders and their oil circuits are integrated with the calf skeleton, and the sensing and control elements such as displacement sensors, oil pressure sensors, and servo valves are highly integrated. The hydraulic system design is simplified, the messy structure of the complex oil circuit is avoided, the stiffness of the ankle joint structure is improved, the weight is reduced, it is more flexible, and the bionic performance is better.

[0057] The present invention adopts a 2PSU&U parallel mechanism, wherein the 2PSU&U represents a two-degree-of-freedom parallel mechanism, PSU represents the kinematic pair on the driving branch chain of the parallel mechanism, wherein P represents the moving pair, S represents the ball pair, U represents the universal joint pair, and &U represents that the kinematic pair on the main chain is a universal joint pair.

[0058] Specific implementation method 2: Combination Figures 1 to 4 , Figure 7This embodiment further includes a linear guide rail 14 and a linear guide rail 2 15, which are arranged in parallel along the length direction of the calf frame 7 and are respectively located directly below the two groups of hydraulic cylinders, and the linear guide rail 1 14 and the linear guide rail 2 15 are fixedly connected to the calf frame 7. Other components and connection relationships are the same as those of the specific embodiment 1.

[0059] Specific implementation method three: Combination Figures 1 to 4 , Figure 7 This embodiment is described. The ankle joint piston assembly of this embodiment includes a piston rod, a slider 13, and a slider connector 6. One end of the piston rod is placed inside the hydraulic cylinder, and the other end of the piston rod is fixedly connected to the slider 13 through the slider connector 6. The slider 13 is slidably connected to the linear guide rail 1 14 and / or the linear guide rail 2 15. In this way, the movement of the piston rod in the hydraulic cylinder drives the slider 13 to perform corresponding linear motion on the linear guide rail 1 14 or the linear guide rail 2 15. Other components and connection relationships are the same as those of the specific embodiment 1 or 2.

[0060] Specific implementation method four: Combination Figure 1 and Figure 7 To explain this embodiment, the two-force rod connecting hinge of this embodiment includes a two-force rod shaft 18 and a radial spherical bearing 19. The end of the piston rod is processed into a circular ring structure, and the radial spherical bearing 19 is installed in the inner hole of the circular ring structure. The middle part of the two-force rod shaft 18 is inserted into the inside of the radial spherical bearing 19. The fork-shaped structure at the head end of the ankle joint two-force rod 5 is processed with an axial hole, and the two ends of the two-force rod shaft 18 are rotatably connected to the fork-shaped structure at the head end of the ankle joint two-force rod 5. With such a configuration, the radial spherical bearing 19 is a built-in radial spherical sliding bearing with good deviation correction ability, making the drive more flexible. Other components and connection relationships are the same as those of specific embodiments one, two or three.

[0061] Specific implementation method five: Combination Figure 2 , Figure 3 and Figure 5 This embodiment is described. The two-force rod cross-axis hinge of this embodiment includes a two-force rod shaft 2 3 and a two-force rod cross-axis sleeve 4. The two-force rod cross-axis sleeve 4 is rotatably connected to the fork-shaped structure at the end of the ankle joint two-force rod 5 through the shaft rods at both ends. The middle part of the two-force rod shaft 2 3 is inserted into the middle shaft sleeve of the two-force rod cross-axis sleeve 4, and the two ends of the two-force rod shaft 2 3 are rotatably connected to the corresponding two-force rod shaft seat 22. Other components and connection relationships are the same as those of the specific embodiments one, two, three or four.

[0062] Specific implementation method six: Combination Figure 4 , Figure 5 and Figure 7This embodiment is described. The ankle cross-axis hinge of this embodiment includes an ankle shaft 17 and an ankle cross-axis sleeve 16. The bottoms of the two hollow side panels of the calf skeleton 7 are processed with shaft holes. The ankle cross-axis sleeve 16 is rotatably connected to the bottoms of the two hollow side panels through shaft rods at both ends. The middle of the ankle shaft 17 is inserted into the ankle cross-axis sleeve 16, and the two ends of the ankle shaft 17 are rotatably connected to the ankle shaft seat 21. Other components and connection relationships are the same as those of the specific embodiments one, two, three, four or five.

[0063] Specific implementation method seven: Combination Figures 2 to 4 To explain this embodiment, this embodiment also includes a rodless chamber oil pressure sensor 9, a servo valve 10 and a rod chamber oil pressure sensor 11. The rodless chamber oil pressure sensor 9, the servo valve 10 and the rod chamber oil pressure sensor 11 are all located at the rear side of the calf skeleton 7. The servo valve 10 is installed on the hydraulic cylinder. The servo valve 10 is connected to the rod chamber and the rodless chamber of the hydraulic cylinder respectively through a hydraulic oil circuit integrally formed with the hydraulic cylinder. The pressure probe of the rodless chamber oil pressure sensor 9 is inserted into the rodless chamber of the hydraulic cylinder, and the pressure probe of the rod chamber oil pressure sensor 11 is inserted into the rod chamber of the hydraulic cylinder. With such an arrangement, the posture and other information perception can be realized through the rodless chamber oil pressure sensor 9 and the rod chamber oil pressure sensor 11 on the hydraulic cylinder, which can realize control feedback and increase control accuracy. Other components and connection relationships are the same as those of specific embodiments one, two, three, four, five or six.

[0064] In this embodiment, the oil circuit is designed on the surface of the hydraulic cylinder, the oil pressure sensor and the servo valve are located on the oil circuit at the rear of the calf, the inner hole is directly 3D printed, and the installation position is finely machined.

[0065] Specific implementation method eight: Combination Figure 7 This embodiment further includes a displacement sensor, which is installed inside the hydraulic cylinder. With this arrangement, the displacement sensor on the hydraulic cylinder can sense information such as posture, realize control feedback, and increase control accuracy. Other components and connection relationships are the same as those of the first, second, third, fourth, fifth, sixth, or seventh embodiments.

[0066] Specific implementation method nine: Combination Figures 1 to 3 This embodiment further includes a shock-absorbing knee 8, which is mounted on the upper front end of the calf frame 7. This arrangement allows the bipedal robot to have a shock-absorbing effect when kneeling or falling forward. Other components and connection relationships are the same as those of the first, second, third, fourth, fifth, sixth, seventh or eighth embodiments.

[0067] Specific implementation method ten: Combination Figures 2 to 4This embodiment is described. This embodiment also includes a hydraulic controller 12, which is installed at the rear end of the upper middle part of the calf frame 7. The hydraulic controller 12 is connected to the servo valve 10. In this way, the servo valve 10 is controlled by the hydraulic controller 12 to control the flow rate, speed and direction of the hydraulic oil flowing into the hydraulic cylinder. The other components and connection relationships are the same as those of the first, second, third, fourth, fifth, sixth, seventh, eighth or ninth embodiment.

[0068] How it works

[0069] Combination Figures 1 to 23 The working principle of the two-degree-of-freedom parallel drive humanoid ankle joint mechanism of the present invention is described as follows:

[0070] During operation, the hydraulic oil enters the two groups of hydraulic cylinders through the internal oil circuit under the control of two servo valves 10, and then pushes the two groups of piston rods to move respectively. The rodless chamber oil pressure sensor 9, the rod chamber oil pressure sensor 11 and the displacement sensor on the hydraulic cylinder are used to sense information such as posture. The movement of the piston rod in the hydraulic cylinder drives the slider 13 to perform corresponding linear motion on the linear guide rail 14 or the linear guide rail 2 15. The slider 13 is connected to the anthropomorphic foot 1 through a multi-degree-of-freedom transmission connecting rod (a two-force rod connecting hinge, an ankle joint two-force rod 5 and a two-force rod cross-axis hinge). The bottom of the calf skeleton 7 is connected to the anthropomorphic foot 1 through an ankle joint cross-axis hinge. When the two groups of hydraulic cylinders push the piston rods to move synchronously, the anthropomorphic foot 1 rotates in the pitch direction; when the two groups of hydraulic cylinders push the piston rods to move asynchronously, the anthropomorphic foot 1 rotates in the side swing direction.

[0071] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A two-degree-of-freedom parallel-driven humanoid ankle joint mechanism, characterized in that: It comprises a humanoid foot (1), an ankle joint base (2), a calf frame (7), an ankle joint cross-axis hinge, two groups of hydraulic cylinders, two groups of ankle joint piston assemblies, two ankle joint two-force rods (5), two two-force rod connecting hinges and two two-force rod cross-axis hinges. The main body of the calf frame (7) comprises two hollow side plates arranged opposite to each other and two groups of hydraulic cylinders arranged in parallel between the two hollow side plates along the length direction of the calf frame (7). The two groups of hydraulic cylinders are integrally formed with the calf frame (7). The two ends of the ankle joint two-force rod (5) are processed into a fork-shaped structure. The two ankle joint two-force rods (5) are parallel to each other. A humanoid foot (1) is arranged directly below the two groups of hydraulic cylinders, and directly below the calf frame (7). An ankle joint base (2) is installed at the top of the humanoid foot (1). The ankle joint base (2) includes a base plate (20), an ankle joint shaft seat (21) and two two-force rod shaft seats (22). The ankle joint shaft seat (21) is installed at the rear side of the middle part of the upper end surface of the base plate (20). The two two-force rod shaft seats (22) are symmetrically arranged on both sides in front of the ankle joint shaft seat (21) with the midline of the length direction of the base plate (20) as the center. The bottom ends of the two two-force rod shaft seats (22) are fixedly connected to the base plate (20). The two groups of hydraulic cylinders Two groups of ankle joint piston assemblies are respectively installed on the upper surface, the piston rods in the two groups of ankle joint piston assemblies are respectively hinged to the fork-shaped structures at the head ends of the two ankle joint two force rods (5) through two two-force rod connecting hinges, the fork-shaped structures at the ends of the two ankle joint two force rods (5) are respectively hinged to the two two force rod shaft seats (22) through two two force rod cross-axis hinges, the two force rod connecting hinges include a two force rod shaft 1 (18) and a radial joint bearing (19), the piston rod end is processed into a circular ring structure, the inner hole of the circular ring structure is installed with a radial joint bearing (19), and the radial joint bearing (19) is inner A radial spherical sliding bearing is arranged, the middle part of the two-force rod shaft (18) is inserted into the inside of the radial joint bearing (19), an axial hole is processed on the fork-shaped structure at the head end of the ankle joint two-force rod (5), the two ends of the two-force rod shaft (18) are rotatably connected to the fork-shaped structure at the head end of the ankle joint two-force rod (5), the bottom of the calf frame (7) is hinged to the ankle joint shaft seat (21) through the ankle joint cross-axis hinge, when the two groups of hydraulic cylinders push the two groups of piston rods to move synchronously, the humanoid foot (1) can rotate in the pitch direction, and when the two groups of hydraulic cylinders push the two groups of piston rods to move asynchronously, the humanoid foot (1) can rotate in the side swing direction.

2. A two-degree-of-freedom parallel-driven humanoid ankle joint mechanism according to claim 1, characterized in that: It also includes a linear guide rail 1 (14) and a linear guide rail 2 (15). The linear guide rail 1 (14) and the linear guide rail 2 (15) are arranged in parallel along the length direction of the calf frame (7) and are respectively located directly below the two groups of hydraulic cylinders. The linear guide rail 1 (14) and the linear guide rail 2 (15) are fixedly connected to the calf frame (7).

3. The two-degree-of-freedom parallel-driven humanoid ankle joint mechanism according to claim 2, characterized in that: The ankle joint piston assembly comprises a piston rod, a slider (13), and a slider connector (6). One end of the piston rod is placed inside the hydraulic cylinder, and the other end of the piston rod is fixedly connected to the slider (13) via the slider connector (6). The slider (13) is slidably connected to a linear guide rail 1 (14) and / or a linear guide rail 2 (15).

4. The two-degree-of-freedom parallel-driven humanoid ankle joint mechanism according to claim 3, characterized in that: The two-force rod cross-axis hinge comprises a two-force rod shaft (3) and a two-force rod cross-axis sleeve (4); the two-force rod cross-axis sleeve (4) is rotatably connected to a fork-shaped structure at the end of an ankle joint two-force rod (5) through shafts at both ends; the middle part of the two-force rod shaft (3) is inserted into the middle shaft sleeve of the two-force rod cross-axis sleeve (4); and the two ends of the two-force rod shaft (3) are rotatably connected to corresponding two-force rod shaft seats (22).

5. The two-degree-of-freedom parallel-driven humanoid ankle joint mechanism according to claim 4, characterized in that: The ankle joint cross-axis hinge comprises an ankle joint axis (17) and an ankle joint cross-axis sleeve (16). The bottoms of the two hollow side plates of the calf frame (7) are both processed with axis holes. The ankle joint cross-axis sleeve (16) is rotatably connected to the bottoms of the two hollow side plates through axis rods at both ends. The middle part of the ankle joint axis (17) is inserted into the ankle joint cross-axis sleeve (16), and the two ends of the ankle joint axis (17) are rotatably connected to the ankle joint axis seat (21).

6. A two-degree-of-freedom parallel-driven humanoid ankle joint mechanism according to claim 1 or 5, characterized in that: It also includes a rodless chamber oil pressure sensor (9), a servo valve (10) and a rod chamber oil pressure sensor (11). The rodless chamber oil pressure sensor (9), the servo valve (10) and the rod chamber oil pressure sensor (11) are all located on the rear side of the calf frame (7). The servo valve (10) is installed on the hydraulic cylinder. The servo valve (10) is connected to the rod chamber and the rodless chamber of the hydraulic cylinder through a hydraulic oil circuit integrally formed with the hydraulic cylinder. The pressure probe of the rodless chamber oil pressure sensor (9) is inserted into the rodless chamber of the hydraulic cylinder, and the pressure probe of the rod chamber oil pressure sensor (11) is inserted into the rod chamber of the hydraulic cylinder.

7. The two-degree-of-freedom parallel-driven humanoid ankle joint mechanism according to claim 6, characterized in that: It also includes a displacement sensor, which is installed inside the hydraulic cylinder.

8. The two-degree-of-freedom parallel-driven humanoid ankle joint mechanism according to claim 7, characterized in that: It also includes a shock-absorbing knee (8), which is mounted on the upper front end of the calf frame (7).

9. The two-degree-of-freedom parallel-driven humanoid ankle joint mechanism according to claim 8, characterized in that: It also includes a hydraulic controller (12), which is installed at the rear end of the upper middle part of the calf frame (7), and is connected to the servo valve (10).

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