A robotic ankle device

Abstract

The present invention discloses a robot ankle device, which relates to the technical field of robot foot structure, including a piston cylinder, a piston rod, a connecting rod and a foot-end support body, wherein a main supporting rod is fixedly connected to the middle part of the bottom end of the piston cylinder, and an end of the main supporting rod is connected to the middle part of the foot-end support body through a ball joint; a plurality of sealing chambers are arranged in parallel in the piston cylinder, a piston rod is slidably arranged in the sealing chamber, an upper piston and a lower piston are arranged on the piston rod at intervals, an upper working chamber is provided between the upper piston and the top end of the sealing chamber, and a lower working chamber is provided between the lower piston and the bottom end of the sealing chamber; the bottom end of the piston rod passes through the sealing chamber and is hinged to one end of the connecting rod, and the other end of the connecting rod is hinged to the foot-end support body; in the present invention, the piston cylinder, the piston rod and the connecting rod are arranged, so that the piston rod and the connecting rod both have stretching and retraction functions, which are similar to the multiple ligaments in the ankle joint, and can perform adaptive posture adjustment on the foot-end support body according to the ground shape, and the structure is simple and the adjustment process is rapid.

Description

Technical Field

[0001] The present invention relates to the technical field of robot foot structures, and in particular to a robot ankle device. Background Art

[0002] The complex structure of the human ankle joint determines that its movement forms include: flexion and extension in the sagittal plane, internal and external rotation in the frontal plane, and internal and external rotation in the horizontal plane. The human ankle joint is a pulley joint. In normal walking movement, the placement center of the bionic talus of the ankle joint in the ankle fossa is constantly changing, and its movement trajectory is elliptical. The axis of activity of the ankle joint has a certain inclination and is often changing. During walking movement, the instantaneous rotation center of the ankle joint falls within a small range near the bionic talus body. The main movement of the ankle joint is flexion and extension in the sagittal plane, while the internal and external rotation and internal and external rotation and internal and external rotation have relatively small amplitudes. Therefore, when designing an ankle prosthesis, it mainly provides flexion and extension activities in the sagittal plane, and has a fixed rotation center and rotation axis. At the same time, it is designed to be unconstrained and can perform a certain degree of micro-lateral movement and rotation activities.

[0003] In the invention patent with application number "201910615935.3" and name "Ankle Prosthesis", the screw shaft of the ball screw is driven by a driving motor to rotate, so that the nut driving the pull rod that moves linearly along the screw shaft drives the ankle connecting seat and the ankle support frame to rotate relative to each other. In addition, a booster spring is provided between the support platform fixed on the ankle support frame and the nut. The booster spring releases the elastic potential energy generated by the compression deformation instantaneously, and drives the ankle prosthesis with a sufficiently large instantaneous booster torque, which can better assist the prosthetic foot of the ankle joint to push off the ground and enable amputees to maintain a steady and natural gait. However, its impact buffering ability on the foot and the ground, and its adaptability to different terrain environments are relatively poor. The invention patent with application number "201010286882.4" and name "bionic ankle joint" is a bionic ankle joint that can conveniently provide active power. It adopts a combination of active control and passive control, which is conducive to reducing energy loss, and can achieve a motion law close to the angle change of the normal human ankle joint, while meeting the requirements of flexibility and stability when the human ankle joint moves. However, the feedback signal of the ankle joint movement angle change is provided by the angle sensor, and the movement law close to the normal human ankle joint angle change is achieved through the data acquisition system and data control system. The error is large, and the structure is complex. It cannot achieve automatic buffering according to the road conditions and imitate the movement of the normal ankle joint.

[0004] Therefore, developing ankle devices for leg-foot robots with similar functions is one of the new focuses and difficulties currently facing the field of leg-foot robot research. Summary of the invention

[0005] The purpose of the present invention is to provide a robot ankle device to solve the problems existing in the prior art, which can adaptively adjust the posture of the foot end support body according to the ground shape, and has a simple structure and a rapid adjustment process.

[0006] To achieve the above-mentioned purpose, the present invention provides the following scheme: The present invention provides a robot ankle device, including a piston cylinder, a piston rod, a connecting rod and a foot-end support body, the middle part of the bottom end of the piston cylinder is fixedly connected to a main support rod, and the end of the main support rod is connected to the middle part of the foot-end support body through a ball joint; a plurality of sealed cavities are arranged in parallel in the piston cylinder, the piston rod is slidably arranged in the sealed cavity, the plurality of piston rods are arranged in parallel with the main support rod and surround the periphery of the main support rod, an upper piston and a lower piston are arranged on the piston rod at intervals, an upper working chamber is provided between the upper piston and the top end of the sealed chamber, and a lower working chamber is provided between the lower piston and the bottom end of the sealed chamber; the bottom end of the piston rod passes through the sealed chamber and is hinged to one end of the connecting rod, and the other end of the connecting rod is hinged to the foot-end support body.

[0007] Preferably, along the axial direction of the piston rod, the connecting rod is arranged to be inclined outward.

[0008] Preferably, both ends of the connecting rod are connected to the piston rod and the foot-end support body by ball joints.

[0009] Preferably, the connecting rod includes an upper connecting rod split and a lower connecting rod split, the top end of the upper connecting rod split is connected to the piston rod via a cross universal joint, and the bottom end of the lower connecting rod split is connected to the foot end support body via a cross universal joint; the bottom end of the upper connecting rod split is coaxially rotatably connected to the top end of the lower connecting rod split.

[0010] Preferably, the bottom end of the upper connecting rod split has a small diameter section extending axially, and the small diameter section is also provided with an axial internal threaded hole, the top end of the lower connecting rod split is threadedly connected to one end of the inner thread cover, the other end of the inner thread cover is sleeved on the small diameter section, and a sleeve is also provided between the middle part of the inner thread cover and the small diameter section, the end of the sleeve has an annular edge extending radially inward, the annular edge is located at the end of the small diameter section, and the end of the annular edge also has a baffle, a fastening bolt passes through the baffle and is tightened in the small diameter section, and the nut of the fastening bolt presses the ends of the sleeve and the inner thread cover against the end of the upper connecting rod split.

[0011] Preferably, a wear-resistant gasket is further provided between the upper connecting rod split body and the inner thread cover.

[0012] Preferably, O-rings are provided on the outer walls of the upper piston and the lower piston.

[0013] Preferably, the piston cylinder comprises an upper cylinder body and a lower cylinder body which are sealed and connected, the upper piston is located in the cavity of the upper cylinder body, and the lower piston is located in the cavity of the lower cylinder body.

[0014] Compared with the prior art, the present invention has achieved the following technical effects:

[0015] 1. The present invention provides a piston cylinder, a piston rod and a connecting rod, so that the piston rod and the connecting rod have the functions of stretching and retracting, similar to the multiple ligaments in the ankle joint, and can adaptively adjust the posture of the foot end support body according to the ground shape. It has a simple structure and a rapid adjustment process, which is very conducive to use and promotion on various walking robots;

[0016] 2. The present invention uses a connecting rod as a connection transition between the piston rod and the foot-end support body, which promotes the symmetrical integrated design of the piston cylinder. The outward tilting of the connecting rod can increase the contact range and adjustment range between the foot-end support body and the ground. At the same time, the piston cylinder does not need to change its volume significantly, which can effectively reduce the overall volume of the ankle device and achieve the purpose of lightweight structural design.

[0017] 3. The connecting rod in the present invention has a certain rotation ability, which can improve the movement performance of the ankle device and avoid the jamming situation that is easy to occur when the two ends of the connecting rod adopt a hinge structure with a single rotation direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0019] Figure 1 is a schematic diagram of the overall structure of the ankle device of the present invention;

[0020] Figure 2 is a side cross-sectional view of the foot and ankle device;

[0021] Figure 3 It is a schematic diagram of the connection structure between the upper connecting rod split and the lower connecting rod split;

[0022] Figure 4 It is a schematic diagram of the explosion structure of the piston cylinder;

[0023] Figure 5 Schematic diagram of the position of the foot and ankle device in two states;

[0024] Among them, 1. piston rod; 2. foot end support body; 3. main support rod; 4. upper piston; 5. lower piston; 6. upper working chamber; 7. lower working chamber; 8. upper connecting rod split; 9. lower connecting rod split; 10. cross universal coupling; 11. small diameter section; 12. inner thread cover; 13. sleeve; 14. fastening bolt; 15. wear-resistant gasket; 16. upper cylinder body; 17. lower cylinder body; 18. seal; 19. connecting flange; 20. baffle. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The purpose of the present invention is to provide a robot ankle device to solve the problems existing in the prior art, which can adaptively adjust the posture of the foot end support body according to the ground shape, and has a simple structure and a rapid adjustment process.

[0027] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] like Figure 1 to Figure 4 As shown, this embodiment provides a robot ankle device, including a piston cylinder, a piston rod 1, a connecting rod and a foot-end support body 2. A main support rod 3 is fixedly connected to the middle of the bottom end of the piston cylinder, and the end of the main support rod 3 is connected to the middle of the foot-end support body 2 through a ball joint, but it does not necessarily need to be connected to the center position of the foot-end support body 2. Specifically, it can be selected according to the overall structure of the robot leg and its movement mode; the main support rod 3 serves as the main support of the piston cylinder and the robot leg structure, similar to the tibia and fibula in the ankle joint; a plurality of sealed cavities are arranged in parallel in the piston cylinder, and a piston rod 1 is slidably arranged in the sealed cavity, and the plurality of piston rods 1 are connected to the main support rod 3 is arranged in parallel and surrounds the periphery of the main support rod 3. An upper piston 4 and a lower piston 5 are arranged on the piston rod 1 at intervals. An upper working chamber 6 is provided between the upper piston 4 and the top end of the sealed chamber, and a lower working chamber 7 is provided between the lower piston 5 and the bottom end of the sealed chamber. The upper working chamber 6 and the lower working chamber 7 are both filled with inert gas components, wherein the upper piston 4 can be the end of the piston rod 1, and the upper piston 4 and the lower piston 5 can also be other structures that can compress the gas components and cause the volumes of the upper working chamber 6 and the lower working chamber 7 to change; the bottom end of the piston rod 1 passes through the sealed chamber and is hinged to one end of the connecting rod, and the other end of the connecting rod is hinged to the foot-end support body 2.

[0029] like Figure 5As shown in the figure, when the robot switches from the swing phase (state one) to the support phase (state two) (the support phase is the whole process of the foot contacting the ground, and the support phase starts at the initial landing; the swing phase is the period when the foot is not in contact with the ground (moving in the air) and the limbs move forward, and the swing phase starts at the moment the foot is lifted off the ground), one end of the foot-end support body 2 contacts the ground first, and the contact force with the ground will generate an overturning moment with the ball joint between the main support rod 3 and the foot-end support body 2 as the rotation center, causing the foot-end support body 2 to rotate around the ball joint, and part of the activity The plug rod 1-connecting rod combination is stretched, and the rest of the piston rod 1-connecting rod combination is retracted; the lower piston 5 in the stretched piston rod 1 compresses the gas in the lower working chamber 7, the pressure in the lower working chamber 7 gradually increases, and the pressure in the upper working chamber 6 gradually decreases, and the piston rod 1 will gradually have a tendency to retract, thereby generating a pull-back force on the foot-end support body 2. The pull-back force can not only suppress the speed of change of the posture of the foot-end support body 2, but also prepare for the foot-end support body 2 to switch to the swing phase, which has a positive effect on the overall posture stability of the robot. The pressure in the upper working chamber 6 corresponding to the retracted piston rod 1 gradually increases, and the pressure in the lower working chamber 7 gradually decreases, and the piston rod 1 will gradually have a tendency to extend, which can not only generate a large thrust on the foot support body, making its support more stable, but also quickly return to a natural state after the foot-end support body 2 switches to the swing phase. When the robot switches from the supporting phase to the swinging phase, the piston rod 1 returns to its natural state, that is, the original position, under the combined force of the corresponding upper working chamber 6 and lower working chamber 7, and moves repeatedly.

[0030] Therefore, in this embodiment, by setting the piston cylinder, piston rod 1 and connecting rod, the piston rod 1-connecting rod have stretching and retraction functions, similar to the multiple ligaments in the ankle joint, and can adaptively adjust the posture of the foot end support body 2 according to the ground shape. It has a simple structure and a rapid adjustment process, which is very conducive to use and promotion on various walking robots.

[0031] Furthermore, in the present embodiment, the connecting rod is arranged to be inclined outward along the axial direction of the piston rod 1; in the present embodiment, the connecting rod is used as a connection transition between the piston rod 1 and the foot-end support body 2, which facilitates the symmetrical integrated design of the piston cylinder, and the outward inclined arrangement of the connecting rod can increase the contact range and adjustment range between the foot-end support body 2 and the ground, and at the same time, the piston cylinder does not need to significantly change its volume, which can effectively reduce the overall volume of the ankle device and achieve the purpose of lightweight structural design.

[0032] As a connecting rod structure, both ends of the connecting rod are connected to the piston rod 1 and the foot end support body 2 by ball joints, so that the connecting rod can rotate appropriately, improve the movement performance of the ankle device, and avoid the jamming situation that is easy to occur when the two ends of the connecting rod adopt a hinge structure with a single rotation direction.

[0033] As another structure of the connecting rod, the connecting rod includes an upper connecting rod split 8 and a lower connecting rod split 9. The top end of the upper connecting rod split 8 is connected to the piston rod 1 through a cross universal joint 10, and the bottom end of the lower connecting rod split 9 is connected to the foot-end support body 2 through a cross universal joint 10. The cross universal joint 10 is fixedly connected to the connecting rod, the piston rod 1 and the foot-end support body 2 to avoid redundant degrees of freedom of the ankle device and make it difficult to control. In order to achieve the purpose of the connecting rod having a certain rotational kinetic energy, the bottom end of the upper connecting rod split 8 is coaxially rotatably connected with the top end of the lower connecting rod split 9. Specifically, the bottom end of the upper connecting rod split 8 is axially extended with a small diameter section 11, and the small diameter section 11 is also provided with an axial internal threaded hole. The top end of the lower connecting rod split 9 is threadedly connected to one end of the inner thread cover 12, and the other end of the inner thread cover 12 is sleeved on the small diameter section 11, and a sleeve 13 is also provided between the middle part of the inner thread cover 12 and the small diameter section 11. The end of the sleeve 13 has an annular edge extending radially inward, and the annular edge is located at the end of the small diameter section 11. The end of the annular edge also has a baffle 20, and a fastening bolt 14 passes through the baffle 20 and is tightened on the small diameter section 11. Inside, the nut of the fastening bolt 14 presses the end of the sleeve 13 and the inner thread cover 12 against the end of the upper connecting rod split 8, so that when the upper connecting rod split 8 and the lower connecting rod split 9 rotate relative to each other, the inner thread cover 12 needs to overcome the friction between it and the end face of the upper connecting rod split 8 and the outer wall of the small diameter section 11 to rotate. When the tightening degree of the fastening bolt 14 is adjusted, the pressure between the inner thread cover 12 and the end face of the upper connecting rod split 8 can be adjusted, thereby adjusting the friction that the inner thread cover 12 needs to overcome when rotating, and the rotation ability of the connecting rod can be adjusted according to different terrain conditions.

[0034] In order to prevent excessive wear of the end surface of the upper connecting rod split body 8 , a wear-resistant gasket 15 is further provided between the end of the upper connecting rod split body 8 and the inner thread cover 12 in this embodiment.

[0035] It should be noted that when the connecting rod adopts the form of a rotational connection between the upper connecting rod split 8 and the lower connecting rod split 9, preferably, the rotation direction of the rotating axis on the cross universal joint 10 on the foot-end support body 2 should be toward the rotation center of the main support rod 3 to ensure that the main support rod 3 can rotate in any direction around the rotation center; and the rotation direction of the rotating axis on the cross universal joint 10 at the end of the piston rod 1 is also toward the setting direction of the rotation center, but because relative rotation can occur between the upper connecting rod split 8 and the lower connecting rod split 9, its installation accuracy can be appropriately reduced.

[0036] Furthermore, in order to improve the sealing ability, in this embodiment, O-rings are provided on the outer walls of the upper piston 4 and the lower piston 5 .

[0037] Furthermore, in this embodiment, the piston cylinder includes an upper cylinder body 16 and a lower cylinder body 17 which are sealed and connected, and the ends of the upper cylinder body 16 and the lower cylinder body 17 are both provided with seals 18, and a connecting flange 19 is provided between the lower end seal 18 of the upper cylinder body 16 and the upper end seal 18 of the lower cylinder body 17, and the upper cylinder body 16 and the lower cylinder body 17 are both installed on the connecting flange 19 by bolts, and after the upper cylinder body 16 and the lower cylinder body 17 are installed, the through hole on the lower end seal 18 of the upper cylinder body 16 is directly opposite to the through hole on the upper end seal 18 of the lower cylinder body 17, and the piston rod 1 is passed therethrough, the upper piston 4 is located in the cavity of the upper cylinder body 16, and the lower piston 5 is located in the cavity of the lower cylinder body 17. At the same time, in order to ensure the sealing performance, an O-ring is also provided on the outer wall of the part of the piston rod 1 located in the upper seal 18 and the lower seal 18.

[0038] Adaptive changes made according to actual needs are all within the protection scope of the present invention.

[0039] It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any reference numerals in the claims should not be regarded as limiting the claims involved.

Claims

1. A robotic ankle device, characterized in that: It includes a piston cylinder, a piston rod, a connecting rod and a foot-end support body, wherein the middle part of the bottom end of the piston cylinder is fixedly connected with a main supporting rod, and the end of the main supporting rod is connected to the middle part of the foot-end support body through a ball joint; a plurality of sealing chambers are arranged in parallel in the piston cylinder, and the piston rod is slidably arranged in the sealing chamber, and the plurality of piston rods are arranged in parallel with the main supporting rod and surround the periphery of the main supporting rod, an upper piston and a lower piston are arranged on the piston rod at intervals, an upper working chamber is provided between the upper piston and the top end of the sealing chamber, and a lower working chamber is provided between the lower piston and the bottom end of the sealing chamber; the piston rod The bottom end of the connecting rod passes through the sealed cavity and is hinged to one end of the connecting rod, and the other end of the connecting rod is hinged to the foot-end support body; the piston cylinder comprises an upper cylinder body and a lower cylinder body that are sealed and connected, the upper piston is located in the cavity of the upper cylinder body, and the lower piston is located in the cavity of the lower cylinder body; the connecting rod comprises an upper connecting rod split and a lower connecting rod split, the top end of the upper connecting rod split is connected to the piston rod through a cross universal coupling, and the bottom end of the lower connecting rod split is connected to the foot-end support body through a cross universal coupling; the bottom end of the upper connecting rod split is coaxially rotatably connected with the top end of the lower connecting rod split; The bottom end of the upper connecting rod split body is axially extended with a small diameter section, and the small diameter section is also provided with an axial internal threaded hole, the top end of the lower connecting rod split body is threadedly connected to one end of the inner thread cover, and the other end of the inner thread cover is sleeved on the small diameter section, and a sleeve is also provided between the middle part of the inner thread cover and the small diameter section, the end of the sleeve has an annular edge extending radially inward, the annular edge is located at the end of the small diameter section, and the end of the annular edge is also provided with a baffle, a fastening bolt passes through the baffle and is tightened in the small diameter section, and the nut of the fastening bolt presses the ends of the sleeve and the inner thread cover to the end of the upper connecting rod split body; When the upper connecting rod split and the lower connecting rod split rotate relative to each other, the inner thread cover needs to overcome the friction between it and the end face of the upper connecting rod split and the outer wall surface of the small diameter section to rotate. By adjusting the tightening degree of the fastening bolt, the pressure between the inner thread cover and the end face of the upper connecting rod split is further adjusted, thereby adjusting the friction force that the inner thread cover needs to overcome when rotating, thereby adjusting the rotation ability of the connecting rod according to different terrain conditions.

2. The robotic ankle device according to claim 1, characterized in that: Along the axial direction of the piston rod, the connecting rod is arranged to be inclined outward.

3. The robotic ankle device according to claim 1 or 2, characterized in that: Both ends of the connecting rod are connected to the piston rod and the foot end support body by ball joints.

4. The robotic ankle device according to claim 1, characterized in that: A wear-resistant gasket is also arranged between the upper connecting rod split body and the inner thread cover.

5. The robotic ankle device according to claim 1, characterized in that: O-type sealing rings are arranged on the outer walls of the upper piston and the lower piston.

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