Three-degree-of-freedom ankle joint prosthesis with gear mechanism

Abstract

The invention discloses a three-degree-of-freedom ankle joint artificial limb with a gear mechanism. The three-degree-of-freedom ankle joint prosthesis with the gear mechanism comprises a prosthesis sleeve; the driving device assembly is arranged in the artificial limb sleeve and connected with the artificial limb sleeve; the gear movement assembly is arranged in the artificial limb sleeve, and the gear movement assembly is meshed with the driving device assembly; one end of the magnetic damping connecting device is connected with the artificial limb sleeve; the prosthetic foot is connected with the other end of the magnetic damping connecting device; wherein the driving device assembly is used for driving the gear movement assembly to move, so that the three-degree-of-freedom ankle joint artificial limb with the gear mechanism has three-active-degree-of-freedom movement; the magnetic damping connecting device provides different damping forces by changing the magnitude of current, and is used for supporting and keeping balance. Through cooperation of the driving device assembly, the gear movement assembly and the magnetic damping connecting device, three-active-freedom-degree movement can be achieved, and therefore the movement controllability and flexibility of the artificial limb system are improved.

Description

Technical Field

[0001] The present application relates to the technical field of prostheses, and in particular to a three-degree-of-freedom ankle joint prosthesis with a gear mechanism. Background Art

[0002] Currently, ankle prostheses on the market mostly have a single active degree of freedom in the sagittal plane and two active degrees of freedom in the sagittal and coronal planes. Usually, the internal rotation and external rotation degrees of freedom in the horizontal plane are used as passive degrees of freedom or fixed. Internal and external rotation of the ankle joint are essential for maintaining proper gait, balance and functional activities. For example, when walking, internal rotation allows the foot to adapt to uneven ground. During weight-bearing activities, external rotation helps stabilize the ankle. Therefore, compared with the natural ankle joint, the range of motion of the ankle prostheses currently on the market is limited, and they cannot adapt to complex terrain and changing gaits. Due to the lack of freedom of the ankle prosthesis, it will also cause instability when the patient walks or performs other exercises, increasing the risk of the patient falling and posing a safety hazard.

[0003] The rigid structure of the prosthesis makes patients more prone to fatigue, especially when walking or standing for long periods of time.

[0004] Therefore, it is desired to have a technical solution to overcome or at least alleviate at least one of the above-mentioned defects of the prior art.

[0005] Application Contents

[0006] The purpose of the present application is to provide a three-degree-of-freedom ankle prosthesis with a gear mechanism to overcome or at least alleviate at least one of the above-mentioned defects of the prior art.

[0007] To achieve the above objectives, the present application provides a three-degree-of-freedom ankle joint prosthesis with a gear mechanism, wherein the three-degree-of-freedom ankle joint prosthesis with a gear mechanism comprises:

[0008] Prosthetic sleeves;

[0009] A drive assembly, the drive assembly being disposed in the prosthesis sleeve and connected to the prosthesis sleeve;

[0010] A gear motion assembly, the gear motion assembly being disposed in the prosthetic sleeve and meshing with the drive device assembly;

[0011] A magnetic damping connection device, one end of which is connected to the prosthetic sleeve;

[0012] A prosthetic foot, the prosthetic foot is connected to the other end of the magnetic damping connection device; wherein,

[0013] The driving device assembly is used to drive the gear motion assembly to move, so that the three-degree-of-freedom ankle joint prosthesis with the gear mechanism has three active degrees of freedom;

[0014] The magnetic damping connection device is used to provide different damping forces by changing the magnitude of the current, and achieves motion matching with the gear motion component through logical control, thereby providing variable supporting force for the three-degree-of-freedom ankle joint prosthesis with a gear mechanism.

[0015] Optionally, the number of the drive device assemblies is two, and each drive device assembly comprises:

[0016] A driving device body, wherein the driving device body is connected to the prosthesis sleeve;

[0017] A special-shaped gear is connected to the driving device body and meshes with the gear motion assembly.

[0018] Optionally, the driving device body includes a motor assembly, a small helical gear, a large helical gear, an inner worm gear, a small gear, a connecting shaft, a bearing, a small support rod, a support shaft, and a support seat; wherein,

[0019] The motor assembly is connected to the prosthetic sleeve;

[0020] The output shaft of the motor assembly is connected to the small helical gear;

[0021] The small helical gear meshes with the large helical gear;

[0022] The supporting shaft is threadedly connected to the connecting shaft;

[0023] The special-shaped gear is arranged on the connecting shaft and can rotate around the connecting shaft;

[0024] The bearing is installed inside the special-shaped gear;

[0025] The support shaft is threadedly connected to the tail end of the small support rod;

[0026] The front section of the inner worm gear meshes with the pinion gear;

[0027] The small diameter section of the support shaft is used to support the large helical gear;

[0028] The supporting shaft is connected with the artificial limb sleeve through the supporting seat.

[0029] Optionally, the gear motion assembly includes a spherical gear and an output rod, the cross section of the spherical gear is the profile of an involute gear, the gear module is 2, and the number of teeth is 22; one end of the output rod is connected to the spherical gear, and the other end is connected to the prosthetic foot;

[0030] The cross section of the special-shaped gear for meshing with the spherical gear is the profile of an involute gear, the gear module is 2, the number of gear teeth is 11, which is the same as the cross-sectional gear profile module of the spherical gear, the tooth angle is equal, and the transmission ratio is 2:1.

[0031] Optionally, the prosthetic foot comprises:

[0032] A tray, wherein the magnetic damping connection device is arranged on one surface of the tray; and the output rod is connected to the tray;

[0033] A keel connected to the other side of the tray;

[0034] An elastic foot blade, wherein the elastic foot blade is connected to the keel;

[0035] A lower blade is connected to the keel.

[0036] The prosthetic foot further comprises:

[0037] A plantar pressure sensor is arranged at the contact portion between the elastic foot blade and the ground.

[0038] Optionally, a receiving groove is provided on the keel;

[0039] An inertial measurement unit, wherein the inertial measurement unit is disposed in the receiving groove;

[0040] A gyroscope is arranged at the rear end surface of the keel.

[0041] Optionally, a through hole is opened below the prosthetic sleeve;

[0042] The bottom plane of the prosthetic sleeve is threadedly connected to six connecting posts;

[0043] The inner thread of the connecting column is connected with the thread of the ball seat, and the ball seat is hinged with the ball head rod.

[0044] Optionally, the magnetic damping connection device includes a magnetic conductive layer, a steel cylinder, a magnetic seat, a spiral coil, a linear bearing, a conductor layer, a ball head rod, a ball head cover, a ball seat, and a connecting column; wherein,

[0045] The magnetic conductive layer is threadedly connected to the inner wall of the steel cylinder, the magnetic seat is threadedly connected to the inner wall of the steel cylinder, the spiral coil is stuck in the groove of the magnetic seat, the two ends of the magnetic seat are gaskets and linear bearings, the conductor layer is threadedly connected to the ball head rod, and the ball head rod drives the conductor layer to move in the steel cylinder; the right end of the steel cylinder is screwed to the ball head cover, the ball head of the ball head cover is hinged to the ball seat, and the ball seat is threadedly connected to the tray through a connecting column.

[0046] Optionally, the two special-shaped gears are distributed inside the prosthesis sleeve at an angle of 60° to each other, and the meshing planes of the two special-shaped gears and the ball gear are also correspondingly at an angle of 60°.

[0047] The three-degree-of-freedom ankle prosthesis with a gear mechanism of the present application can achieve three-degree-of-freedom movement through the cooperation of a drive device assembly and a gear motion assembly, and the three-degree-of-freedom ankle prosthesis can improve the motion controllability and motion compliance of the prosthetic system through independent and coupled control of the three degrees of freedom of the ankle joint, improve the compliance of the prosthetic system, improve the adaptability to different terrains and gaits, and improve the quality of life of amputees. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 4 is a system schematic diagram of a three-degree-of-freedom ankle prosthesis with a gear mechanism according to an embodiment of the present application.

[0049] Figure 2 yes Figure 1 The schematic diagram of the structure of the special-shaped gears and ball gears in the three-degree-of-freedom ankle joint prosthesis with gear mechanism is shown.

[0050] Figure 3 yes Figure 1 The internal structure diagram of the drive device in the three-degree-of-freedom ankle joint prosthesis with a gear mechanism is shown.

[0051] Figure 4 yes Figure 1 The internal structure diagram of the magnetic damper in the three-degree-of-freedom ankle prosthesis with gear mechanism is shown.

[0052] Figure 5 yes Figure 1 The structural diagram of the prosthetic foot in a three-degree-of-freedom ankle prosthesis with a gear mechanism is shown.

[0053] Figure 6 yes Figure 1 Schematic diagram of the movement of a single special-shaped gear and a ball gear in a three-degree-of-freedom ankle joint prosthesis with a gear mechanism.

[0054] Figure 7 yes Figure 1 The diagram shown is a schematic diagram of the kinematic joint of two special-shaped gears and a ball gear in a three-degree-of-freedom ankle joint prosthesis with a gear mechanism.

[0055] Figure 8 yes Figure 1 The diagram shown is a diagram of the equivalent connecting rod model of the special-shaped gear and ball gear of the three-degree-of-freedom ankle joint prosthesis with a gear mechanism.

[0056] Fig. 9 yes Figure 1 Schematic diagram of the forward kinematics model of two special-shaped gears and a ball gear in a three-degree-of-freedom ankle joint prosthesis with a gear mechanism.

[0057] Fig.10 yes Figure 1 The equivalent model diagram of the damper for the ankle joint is shown.

[0058] Fig.11 yes Figure 1 Schematic diagram of the position of the damper for the ankle joint.

[0059] Fig.12 yes Figure 1 The plan view of the hinge point position of the dynamic platform of the ankle joint damper is shown.

[0060] Fig.13 yes Figure 1 The plan view of the hinge point position of the ankle joint damper is shown.

[0061] Fig.14 yes Figure 1 The overall internal structure diagram of the three-degree-of-freedom ankle prosthesis with a gear mechanism is shown.

[0062] Reference numerals

[0063] 1 Ball gear 2 Special-shaped gear 3 Motor 4 Small helical gear 5 Large helical gear 6 Support shaft 7 Internal worm gear 8 Connecting shaft 9 Bearings 10 Gasket 11 Small gear 12 Small support rod 13 Support seat 14 Prosthetic sleeve 15 Connecting column 16 Tee 17 Ball head 18 Magnetic layer 19 Steel Cylinder 20 Magnetic base 21 Linear Bearings 22 Conductor layer 23 Ball head cover 24 Prosthetic foot 25 tray 26 keel 27 Elastic foot blades 28 Elastic foot blades 29 Solenoid 30 Shoulder 31 Stopper 32 Step gasket 33 Motor support seat 34 Drive device 35 Magnetic damper 36 Inertial Measurement Unit 37 Gyroscope 38 Output rod 39 Foot pressure sensor 101 Driver module DETAILED DESCRIPTION

[0064] In order to make the purpose, technical scheme and advantages of the implementation of this application clearer, the technical scheme in the embodiment of this application will be described in more detail below in conjunction with the drawings in the embodiment of this application. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described embodiments are part of the embodiments of this application, not all of them. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain this application, and should not be construed as limitations on this application. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The embodiments of this application are described in detail below in conjunction with the drawings.

[0065] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the scope of protection of the present application.

[0066] like Figures 1 to 7The three-degree-of-freedom ankle joint prosthesis with a gear mechanism shown includes a prosthetic sleeve, a drive device assembly, a gear motion assembly, a magnetic damping connection device and a prosthetic foot, wherein:

[0067] The drive device assembly is disposed in the prosthesis sleeve and connected to the prosthesis sleeve;

[0068] A gear motion assembly is disposed in the prosthetic sleeve, and the gear motion assembly is meshed with the drive device assembly;

[0069] One end of the magnetic damping connection device is connected to the prosthetic sleeve;

[0070] The prosthetic foot is connected to the other end of the magnetic damping connection device; wherein,

[0071] The driving device assembly is used to drive the gear motion assembly to move, so that the three-degree-of-freedom ankle joint prosthesis with the gear mechanism has three active degrees of freedom;

[0072] The magnetic damping connection device is used to provide different damping forces by changing the magnitude of the current, and achieves motion matching with the gear motion component through logical control, thereby providing variable supporting force for the three-degree-of-freedom ankle joint prosthesis with a gear mechanism.

[0073] The three-degree-of-freedom ankle prosthesis with a gear mechanism of the present application can achieve three-degree-of-freedom movement through the cooperation of a drive device assembly and a gear motion assembly. The three-degree-of-freedom ankle prosthesis can improve the motion controllability and motion compliance of the prosthetic system, improve the adaptability to different terrains and gaits, and improve the quality of life of amputees through independent and coupled control of the three degrees of freedom of the ankle joint.

[0074] In this embodiment, the three degrees of freedom of movement are plantar flexion / dorsiflexion in the sagittal plane, inversion / eversion in the coronal plane, and internal rotation / external rotation in the horizontal plane.

[0075] In this embodiment, there are two drive device assemblies, each of which includes a drive device body and a special-shaped gear 2. The drive device body is connected to the prosthetic sleeve; the special-shaped gear is connected to the drive device body, and the special-shaped gear is meshed with the gear motion assembly.

[0076] In this embodiment, the driving device body includes a motor assembly 3, a small bevel gear 4, a large bevel gear 5, an inner worm gear 7, a small gear 11, a connecting shaft 8, a bearing 9, a small support rod 12, a support shaft 6, and a support seat 13; wherein the motor assembly 3 is connected to the prosthetic sleeve 14; the output shaft of the motor assembly 3 is connected to the small bevel gear 4; the small bevel gear 4 is meshed with the large bevel gear 5; the support shaft 6 is threadedly connected to the connecting shaft 8; the special-shaped gear 2 is arranged on the connecting shaft 8 and can rotate around the connecting shaft 8; the bearing 9 is installed inside the special-shaped gear 2; the support shaft 6 is threadedly connected to the tail end of the small support rod 12; the front section of the inner worm gear 7 is meshed with the small gear 11; wherein the small shaft diameter section of the support shaft 6 is used to support the large bevel gear 5; the support shaft 6 is connected to the prosthetic sleeve 14 through the support seat 13.

[0077] More specifically, see Figure 3 and Fig.12 The motor 3 is connected to the threaded hole of the prosthetic sleeve 14 through the motor support seat 33. The output shaft of the motor 3 is directly connected to the small bevel gear 4. The normal module of the small bevel gear 4 and the large bevel gear 5 is 1.5, the normal pressure angle is 20°, the helical angles are equal in size and opposite in direction, and the meshing conditions are met. The large diameter section of the support shaft 6 is slotted and the two side planes are milled, and it is threadedly connected to the connecting shaft 8. The special-shaped gear 2 can rotate around the connecting shaft 8. The bearing 9 is installed inside the special-shaped gear 2 and positioned by the top shoulder 30 and the gasket 10. The bearing 9 can reduce the friction between the special-shaped gear 2 and the connecting shaft when the meshing rotation is carried out. The slot in the middle diameter section of the support shaft 6 leaves enough movement space for the small gear 11. There is a positioning hole at the bottom of the slot, which is threadedly connected to the tail end of the small support rod 12. The small support rod 12 passes through the center hole of the small gear 11 to ensure the position accuracy of the small gear 11. The front section of the inner worm wheel 7 is developed into a spiral internal tooth surface, forming a meshing motion relationship with the pinion 11. The rear section of the inner worm wheel 7 is provided with a through hole, which is interference fit with the axial diameter section of the support shaft 6. When the pinion 11 meshes and rotates with the inner worm wheel 7, the inner worm wheel 7 can rotate around the fixed axis of the support shaft 6. The small axial diameter section of the support shaft 6 is used to support the large bevel gear 5. There is a block 31 between the two large bevel gears 5 to ensure the movement space of the two small bevel gears 4. The large bevel gear 5 that rotates around the fixed axis of the support shaft has a bearing inside. The stepped gasket 32 ​​can reduce the friction between the large bevel gear 5 and the block 31 and the support shaft 6, and can also serve as a top shoulder of the bearing. Another large bevel gear 5 is fixedly connected to the support shaft 6 and rotates together. The support shaft 6 is connected to the through-hole bolt on the prosthetic sleeve 14 through the support seat 13.

[0078] In this embodiment, the gear motion assembly includes a spherical gear 1 and an output rod 38. The cross section of the spherical gear is the profile of an involute gear, the gear module is 2, and the number of teeth is 22. One end of the output rod 38 is connected to the spherical gear, and the other end is connected to the prosthetic foot.

[0079] The cross section of the special-shaped gear 2 used for meshing with the spherical gear is the profile of an involute gear, the gear module is 2, the number of gear teeth is 11, which is the same as the cross-sectional gear profile module of the spherical gear, the tooth angle is equal, and the transmission ratio is 2:1.

[0080] In this embodiment, the prosthetic foot includes a tray 25, a keel 26, an elastic upper foot blade 27 and a lower blade 28, wherein a magnetic damping connection device is arranged on one surface of the tray 25; an output rod 38 is connected to the tray 25; the keel 26 is connected to the other surface of the tray 25; the elastic upper foot blade 27 is connected to the keel 26; and the lower blade 28 is connected to the keel 26.

[0081] The prosthetic foot further comprises a plantar pressure sensor 39, which is arranged at the contact portion between the elastic foot blade and the ground.

[0082] In this embodiment, a receiving groove is provided on the keel 26;

[0083] The prosthetic foot further comprises an inertial measurement unit 36, which is disposed in the receiving groove; and a gyroscope 37, which is disposed at the rear end surface of the keel.

[0084] More specifically, the tray 25 of the prosthetic foot 24 is screwed to the top of the keel 26, one end of the output rod 38 is fixed to the ball gear 1, and the other end is fixed to the tray 25, and the upper blade 27 and the lower blade 28 of the elastic foot are bolted to the keel 26 to provide support for the prosthesis. The inertial measurement unit is placed in the groove at the front end of the keel 26, responsible for real-time measurement of the angular acceleration of the sagittal and coronal planes of the prosthetic foot 24, and the gyroscope 37 is screwed to the rear end of the keel, responsible for measuring the angular acceleration of the horizontal plane of the prosthetic foot 24, so as to identify the human body's movement intention, and then adjust the trajectory of the output rod 38 in real time.

[0085] See also Figure 5 as well as Fig.12 In this embodiment, a through hole is opened below the prosthetic sleeve 14 to facilitate the matching of the ball gear 1 and the special-shaped gear 2. The bottom plane of the sleeve 14 is threadedly connected with six connecting columns 15. The internal threads of the connecting columns are threadedly connected with the ball seat 16, and the ball seat 16 is hinged with the ball head rod 17.

[0086] In this embodiment, the magnetic damping connection device includes a magnetic conductive layer 18, a steel cylinder 19, a magnetic seat 20, a spiral coil 29, a linear bearing 21, a conductor layer 22, a ball head rod 17, a ball head cover 23, a ball seat 16, and a connecting column 15; wherein,

[0087] The magnetic conductive layer 18 is threadedly connected to the inner wall of the steel cylinder 19, the magnetic base 20 is threadedly connected to the inner wall of the steel cylinder 19, the spiral coil 29 is stuck in the groove of the magnetic base 20, the two ends of the magnetic base 20 are gaskets 10 and linear bearings 21, the conductor layer 22 is threadedly connected to the ball head rod 17, and the ball head rod 17 drives the conductor layer 22 to move in the steel cylinder 19; the right end of the steel cylinder 19 is screwed to the ball head cover 23, the ball head of the ball head cover 23 is hinged to the ball seat 16, and the ball seat 16 is threadedly connected to the tray 25 through the connecting column 15.

[0088] In this embodiment, the two special-shaped gears 2 are distributed inside the prosthesis sleeve 14 at an angle of 60° to each other, and the meshing planes of the two special-shaped gears 2 and the ball gear 1 are also at an angle of 60°.

[0089] The present application is further described in detail below by way of examples. It should be understood that the examples do not constitute any limitation to the present application.

[0090] See also Figure 2 In this embodiment, the ball gear 1 is obtained by cutting on the spherical surface. The cross section of the ball gear 1 is the profile of a common involute gear, the gear module is 2, and the number of teeth is 22. Rotational cutting is performed around the x-axis and y-axis respectively, and the gear profile of any plane within the rotation circle is retained to obtain a spherical tooth structure.

[0091] See also Figure 2 In this embodiment, the special-shaped gear 2 is made by a process similar to gear hobbing. The cross section of the special-shaped gear is the profile of a common involute gear, the gear module is 2, the number of gear teeth is 11, and the cross section gear profile module is the same as that of the ball gear 1, the tooth profile angle is equal, the meshing condition is met, and the transmission ratio is 2:1. As the cross section spur gear profiles of the ball gear 1 and the special-shaped gear 2 mesh, the ball gear 1 acts as a tool to cut the special-shaped gear 2 to generate the tooth surface of the special-shaped gear.

[0092] See also Figure 3In this embodiment, the motor 3 is connected to the threaded hole of the prosthetic sleeve 14 through the motor support seat 33, and the motor 3 shaft is directly connected to the small bevel gear 4. The normal module of the small bevel gear 4 and the large bevel gear 5 is 1.5, the normal pressure angle is 20°, the helical angles are equal in size and opposite in direction, and the meshing conditions are met. The large diameter section of the support shaft 6 is slotted and the two side planes are milled, and it is fixedly connected to the connecting shaft 8. The special-shaped gear 2 can rotate around the connecting shaft 8. The bearing 9 is installed inside the special-shaped gear 2 and positioned by the top shoulder 30 and the gasket 10. The bearing 9 can reduce the friction between the special-shaped gear 2 and the connecting shaft when the meshing rotation is carried out. The slot in the middle diameter section of the support shaft 6 leaves enough movement space for the small gear 11. There is a positioning hole at the bottom end of the slot, which is threadedly connected to the tail end of the small support rod 12. The small support rod 12 passes through the center hole of the small gear 11 to ensure the position accuracy of the small gear 11. The front section of the inner worm wheel 7 is developed into a spiral internal tooth surface, forming a meshing motion relationship with the pinion 11. The rear section of the inner worm wheel 7 is provided with a through hole, which is convenient for being sleeved on the middle diameter section of the support shaft 6. When the pinion 11 meshes and rotates with the inner worm wheel 7, the inner worm wheel 7 can rotate around the fixed axis of the support shaft 6. The small diameter section of the support shaft 6 is used to support the large bevel gear 5. There is a block 31 between the two large bevel gears 5 to ensure the movement space of the two small bevel gears 4. The large bevel gear 5 that rotates around the fixed axis of the support shaft has a bearing inside. The stepped gasket 32 ​​can reduce the friction between the large bevel gear 5 and the block 31 and the support shaft 6, and can also serve as a top shoulder of the bearing. Another large bevel gear 5 is fixedly connected to the support shaft 6 and rotates together. The support shaft 6 is connected to the through-hole bolt on the prosthetic sleeve 14 through the support seat 13.

[0093] See also Figure 1 , Figure 4 and Fig.14 In this embodiment, a through hole is provided below the prosthetic sleeve 14 to facilitate the matching of the ball gear 1 and the special-shaped gear 2. The bottom plane of the sleeve 14 is threadedly connected to six connecting columns 15. The inner thread of the connecting column is threadedly connected to the ball seat 16, and the ball seat 16 is hinged to the ball head rod 17. The magnetic conductive layer 18 is threadedly connected to the inner wall of the steel cylinder 19, and the magnetic seat 20 is threadedly connected to the inner wall of the steel cylinder 19. The spiral coil 29 is stuck in the groove of the magnetic seat 20. The two ends of the magnetic seat 20 are gaskets 10 and linear bearings 21 to reduce friction. The conductor layer 22 is threadedly connected to the ball head rod 17, and the ball head rod 17 drives the conductor layer 22 to move in the steel cylinder 19, thereby generating a damping force. The right end of the steel cylinder 19 is screwed to the ball head cover 23, and the ball head of the ball head cover 23 is hinged to the ball seat 16. The ball seat 16 is threadedly connected to the tray 25 above the prosthetic foot 24 through the connecting column 15.

[0094] See also Figure 5In this embodiment, the tray 25 of the prosthetic foot 24 is screwed to the top of the keel 26, one end of the output rod 38 is fixed to the ball gear 1, and the other end is fixed to the tray 25, and the upper blade 27 and the lower blade 28 of the elastic foot are bolted to the keel 26 to provide support for the prosthesis. The inertial measurement unit 36 ​​is placed in the groove at the front end of the keel 26, responsible for real-time measurement of the angular acceleration of the sagittal and coronal planes of the prosthetic foot 24, and the gyroscope 37 is screwed to the rear end of the keel, responsible for measuring the angular acceleration of the horizontal plane of the prosthetic foot 24, so as to monitor the motion state of the prosthesis and identify the human body's motion intention, and then adjust the trajectory of the output rod 38 in real time.

[0095] See also Figure 6 In actual work, the interaction between ball gear 1 and profiled gear 2 produces three kinds of motion: transmission, rolling and sliding motion, and the transmission ratio of profiled gear 2 to ball gear 1 is 2 to 1. For a single driving profiled gear, when profiled gear 2 rotates around the vertical center axis -2θ N1 When the angle is θ, the ball gear rotates N1 Angle, the teeth of the special-shaped gear 2 mesh with the teeth of the ball gear 1, and the driving force is transmitted from the special-shaped gear 2 to the ball gear 1. When the special-shaped gear 2 rotates around the horizontal axis θ G1 Angle, the ball gear rolls accordingly θ G1 The driving force is transmitted through the rolling rotation of the special-shaped gear 2, thereby driving the rolling rotation of the ball gear 1. When the special-shaped gear 2 rotates around the structural axis of the ball gear 1 by θ H1 When the angle is θ, the rotation of ball gear 1 and the tooth surface of profiled gear 2 form passive sliding, and no driving force is transmitted. When the position of profiled gear 2 is fixed, the interaction of these three motions will interfere and is not completely independent. A single profiled gear 2 can only actively drive two of the three rotational degrees of freedom of ball gear 1, namely, the fixed axis rotation θ around the vertical center axis. N1 Angle and horizontal axis fixed axis rotation θ G1 Angle, its passive sliding motion is driven by another special-shaped gear 2 or two special-shaped gears 2 are driven together. Inside the prosthetic sleeve 14, the driving motor 3 drives the front small bevel gear 4 to mesh with the large bevel gear 5, and the large bevel gear 5 rotates relative to the support shaft 6. The large bevel gear 5 transmits the driving force to the inner worm gear 7, driving the meshing movement between the small gear 11 and the special-shaped gear 2, and the ball gear 1 meshes and rotates accordingly. The driving motor drives the meshing movement of the rear small bevel gear 4 and the large bevel gear 5, and the large bevel gear 5 rotates together with the support shaft 6. The support shaft 6 converts the driving force into the rolling movement of the special-shaped gear 2 and the ball gear 1 through the support rod 8.

[0096] See also Figure 7 and Figure 8, since a single special-shaped gear 2 and ball gear 1 produce three kinds of motion, they can be equivalent to three joints: rolling joint, meshing joint, and sliding joint. Rolling joint and meshing joint are active, and sliding joint is passive. The rolling joint G1 of the first special-shaped gear 2 is connected to the meshing joint N1 through a spherical link a1, the meshing joint N1 is connected to the sliding joint H1 through a spherical link a2, and the link a0 is the fixed bracket of the driving gear. The rolling joint G2 of the second special-shaped gear 2 is connected to the meshing joint N2 through a spherical link b1, the meshing joint N2 is connected to the sliding joint H2 through a spherical link b2, and the link b0 is the fixed bracket of the driving gear. When the ball gear 1 is driven by a single special-shaped gear, the mechanism can be equivalent to a double-link series arm with a passive sliding joint as the end effector. Since the link is spherical, the end effector has two sliding degrees of freedom on the spherical surface with the center of the ball gear 1 as the center. Therefore, when two special-shaped gears 2 drive the ball gear 1, it can be equivalent to being driven in parallel by two series arms. Since each arm is connected to the ball gear through a passive joint and all joints are orthogonal, the output link obtains three rotational degrees of freedom. According to the equivalent link model, the degrees of freedom can be obtained from the Gruebler equation:

[0097]

[0098] Where N is the number of links, J is the number of joints6, and f i is the degree of freedom of the i-th joint, and the degree of freedom of the equivalent linkage mechanism is 3.

[0099] See also Figure 8 and Fig. 9 , the two special-shaped gears 2 and the corresponding driving devices are distributed inside the prosthetic sleeve 14 at an angle of 60°, and the meshing planes of the two special-shaped gears 2 and the ball gear 1 are also 60° accordingly. The three degrees of freedom of the ball gear 1 are realized by the coupled motion of the four active joints G1, N1, G2, and N2 of the two special-shaped gears 2, so they can be regarded as three independent active joints G1, N1, G2 and a subordinate active joint N2. The equivalent joints of the special-shaped gears are connected to the ball gears through equivalent connecting rods, and the rotation angles of the ball gears in three directions can be obtained by the rotation coordinate transformation between the connecting rods. Let the world coordinate system fixed on the bracket (prosthetic sleeve 14) be O, and the coordinate system of the connecting rod a0 coincide with the world coordinate system. The local coordinate system fixed on the ball gear is O A , the coordinate transformation of ball gear and special-shaped gear is expressed as O q C and O q Bi (i=1, 2):

[0100] O q C =R(θ S ,θC ,θ P ), In the formula, θ S is the sagittal rotation angle of ball gear 1, θ C is the crown rotation angle of ball gear 1, θ P is the horizontal rotation angle of ball gear 1, θ Gi is the rolling rotation angle of the i-th special-shaped gear 2, θ Ni is the meshing rotation angle of the i-th special-shaped gear 2, θ Hi is the passive sliding angle of the i-th special-shaped gear 2.

[0101] The relationship between the ball gear and the rotation angle of the two drive modules is as follows:

[0102] θ S1 =θ G1 ,θ S2 =θ G2 ,θ C1 = -2θ N1 ,θ C2 = -2θ N2

[0103] Through the kinematic model, the rotation matrix transformation is performed:

[0104] a0 R a1 =R x (θ G1 ), a1 R a2 =R y (θ N1 ), a2 R C =R x (θ H1 )

[0105] b0 R b1 =R x (θ G2 ), b1 R b2 =R y (θ N2 ), b2 R C =R x (θ H2 )R z (-π / 2), a0 R b0 =R z (β)

[0106]

[0107] Where β is the meshing plane angle between the two special-shaped gears 2 and the ball gear 1.

[0108] Due to the closed circularity:

[0109] a0 R a1 a1 R a2 a2 R C = a0 R b0 b0 R b1 b1 R b2 b2 R C

[0110] Right now:

[0111]

[0112] The calculation can obtain the slave active joint angle N2, the passive sliding angle H1 and the rotation angles on the three surfaces of the ball gear.

[0113]

[0114]

[0115] θ S =arcsin(sinθ N1 (-cosθ G1 cosθ N1 sinθ G2 +cosθ N1 cosθ G2 sinθ G1 cosβ+sinθ N1 cosθ G2 sinβ))

[0116]

[0117] See also Figure 4 and Fig.14 According to the principle of electromagnetic induction, when the magnetic induction lines generated by the energized spiral coil 29 are cut by the moving conductor, the moving conductor layer 22 will generate an induced electromotive force, thereby forming an eddy current in the conductor layer 22, and the eddy current excites a damping force that hinders the relative movement of the conductor and the magnetic field. When the prosthetic foot 24 moves, the six magnetic dampers 35 move in a telescopic manner to generate a supporting force.

[0118] See also Fig.10 and Fig.11, the rotation angles of the ball gear 1 in three directions can be known to obtain the end position of the prosthetic foot 24, thereby obtaining the analytical expression of the rod length change of the magnetic damper 35. The hinge point R of the ball joint connecting the bottom plane of the prosthetic sleeve 14 and the prosthetic foot tray 25 i 、r i (i=1,2,...,6) are connected to form symmetrical hexagons. The bottom plane of the prosthetic sleeve 14 is regarded as a fixed platform, and the top plane of the prosthetic foot tray 25 is regarded as a moving platform. A fixed coordinate system O fixed to the fixed platform is established at the geometric center point E of the fixed platform. E , establish a moving coordinate system O fixed to the moving platform at the geometric center point D of the moving platform D The radius of the fixed platform is the hinge point R i The distance R to the center point E E , the radius of the moving platform is the hinge point r i The distance R to the center point D D , when the platform is in the initial static state, the geometric center D of the moving platform is directly above the geometric center E of the fixed platform.

[0119] See also Fig.12 , hinge point r i In the moving coordinate system O D The position vector in is:

[0120]

[0121] Where φ represents the angle between two adjacent hinge points of the moving platform.

[0122] See also Fig.13 , the position vector of the hinge point Ri in the fixed coordinate system OE can be expressed as:

[0123]

[0124] Where γ represents the angle between two adjacent hinge points of the moving platform.

[0125] Since the geometric center E of the fixed platform coincides with the geometric center C of the ball gear, the coordinate system of the fixed platform is the same as the world coordinate system fixed on the bracket (prosthetic sleeve 14), and the prosthetic foot tray 25 and the ball gear 1 connect the geometric centers of the moving platform and the fixed platform through the output rod 38, the rotation transformation matrix of the moving platform relative to the fixed platform is equal to the rotation transformation matrix of the ball gear 1 relative to the world coordinate system:

[0126]

[0127] The i-th magnetic damper 35 vector l i It can be expressed as:

[0128] l i = E RD D r i +t- E R i (i=1,2,...,6)

[0129] in, E R D represents the rotation matrix of the moving platform relative to the fixed coordinate system, where l i represents the vector of the magnetic damper 35, that is, the vector of the connection point between the magnetic damper 35 and the fixed and movable platforms. t represents the translation vector of the geometric center point of the fixed and movable platforms, that is, the translation vector of the output rod 38.

[0130] The length of the i-th magnetic damper 35 is l i for:

[0131]

[0132] The expansion and contraction variation of the magnetic damper 35 can be expressed as:

[0133] Δl i = l i -l0

[0134] Where l0 is the original magnetic damper length.

[0135] See also Figure 1 and Fig.14 In daily walking tasks, the algorithm is designed using the data from the electromyographic signal sensor, the inertial measurement unit 36, the gyroscope 37, and the plantar pressure sensor 39 to plan the trajectory and generate a trajectory function for the ball gear 1 to move along the path. O q C (t), the rotation angle θ of the two special-shaped gears 2 can be obtained by matrix inverse transformation N1 ,θ N2 ,θ G1 ,θ G2 The rotation angle of motor 3 driving the meshing motion of the special-shaped gear 2 on the left and right sides is generated by the inverse kinematics calculation of motor 3-special-shaped gear 2 and the rotation angle of the motor 3 driving the rolling motion of the profiled gear 2

[0136] In the formula, i n 、i g is the transmission ratio from motor 3 to special-shaped gear 2.

[0137] While the four motors 3 synchronously drive the ball gear 1, the magnetic damper 35 performs passive telescopic motion accordingly. O q C (t) The expansion and contraction change of the magnetic damper 35 obtained by inverse solution Δli The position, velocity, acceleration and other motion parameters of the moving platform are measured in real time, and the current is dynamically adjusted to change the magnetic field strength of the magnetic damper, thereby adjusting the damping force in real time to provide support, so that the prosthetic foot 24 can move stably along the planned trajectory.

[0138] This application has the following advantages:

[0139] 1. The transmission route of motor-bevel gear set-internal worm gear-pinion gear-special-shaped gear-ball gear-output end is adopted to make the drive device compact and save space.

[0140] 2. The application of the ball gear and two special-shaped gears realizes three active degrees of freedom of rotation of the prosthetic foot and simplifies the structure of the drive device.

[0141] 3. The magnetic damper can provide different damping forces by changing the magnitude of the current, providing the device with a support force with variable amplitude and direction, thereby achieving stable movement of the prosthetic foot.

[0142] 4. Considering human-computer interaction, the prosthetic sleeve fully considers human comfort.

[0143] 5. The control of three active degrees of freedom combined with sensing technology can achieve real-time adjustment of the prosthetic foot posture, improve the adaptability of the ankle prosthesis to different terrains, and improve the safety of the system.

[0144] 6. Through the coordinated control of three degrees of freedom, the movement of the natural human ankle joint can be simulated more accurately, the gait adaptability of the prosthesis can be improved, the walking coordination ability of amputees can be improved, and the comfort of the human body can be improved.

[0145] 7. The magnetic damper platform provides passive damping force to help control the movement of the prosthesis, reduce vibration and impact of the prosthetic foot, and reduce user discomfort.

[0146] 8. The active control of the ball gear combined with the passive damping force of the magnetic damper can meet the damping adjustment requirements of different users to achieve the best gait and comfort.

[0147] Although the present application is disclosed as above in terms of a preferred embodiment, it is not intended to limit the present application. Any technical personnel in this field may make possible changes and modifications without departing from the spirit and scope of the present application. Therefore, the scope of protection of the present application shall be based on the scope defined by the claims of the present application.

[0148] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application is described in detail with reference to the above embodiments, a person skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A three-degree-of-freedom ankle joint prosthesis with a gear mechanism, characterized in that: The three-degree-of-freedom ankle joint prosthesis with a gear mechanism comprises: Prosthetic sleeves; A drive assembly, the drive assembly being disposed in the prosthesis sleeve and connected to the prosthesis sleeve; A gear motion assembly, the gear motion assembly being disposed in the prosthetic sleeve and meshing with the drive device assembly; A magnetic damping connection device, one end of which is connected to the prosthetic sleeve; A prosthetic foot, the prosthetic foot is connected to the other end of the magnetic damping connection device; wherein, The driving device assembly is used to drive the gear motion assembly to move, so that the three-degree-of-freedom ankle joint prosthesis with the gear mechanism has three active degrees of freedom; The magnetic damping connection device provides different damping forces by changing the magnitude of the current, thereby providing a variable supporting force for the three-degree-of-freedom ankle joint prosthesis with a gear mechanism.

2. The three-degree-of-freedom ankle joint prosthesis with a gear mechanism as claimed in claim 1, characterized in that: The number of the drive device assemblies is two, and each drive device assembly comprises: A driving device body, wherein the driving device body is connected to the prosthesis sleeve; A special-shaped gear (2), the special-shaped gear is connected to the driving device body, and the special-shaped gear is meshed with the gear motion component.

3. The three-degree-of-freedom ankle joint prosthesis with a gear mechanism as claimed in claim 2, characterized in that: The driving device body comprises a motor assembly (3), a small bevel gear (4), a large bevel gear (5), an inner worm gear (7), a small gear (11), a connecting shaft (8), a bearing (9), a small support rod (12), a support shaft (6), and a support seat (13); wherein: The motor assembly (3) is connected to the prosthetic sleeve (14); The output shaft of the motor assembly (3) is connected to the small helical gear (4); The small helical gear (4) meshes with the large helical gear (5); The supporting shaft (6) is fixedly connected to the connecting shaft (8); The special-shaped gear (2) is arranged on the connecting shaft (8) and can rotate around the connecting shaft (8); The bearing (9) is installed inside the special-shaped gear (2); The support shaft (6) is threadedly connected to the tail end of the small support rod (12); The front section of the inner worm gear (7) is meshed with the pinion gear (11); wherein, The small diameter section of the support shaft (6) is used to support the large helical gear (5); The support shaft (6) is connected to the prosthetic sleeve (14) via a support seat (13).

4. The three-degree-of-freedom ankle joint prosthesis with a gear mechanism as claimed in claim 3, characterized in that: The gear motion assembly comprises a spherical gear (1) and an output rod (38); the cross section of the spherical gear is the profile of an involute gear, the gear module is 2, and the number of teeth is 22; one end of the output rod (38) is connected to the spherical gear, and the other end is connected to the prosthetic foot; The cross section of the special-shaped gear (2) for meshing with the spherical gear is the profile of an involute gear, the gear module is 2, the number of gear teeth is 11, the gear profile module is the same as the cross section of the spherical gear, the tooth angle is equal, and the transmission ratio is 2:

1.

5. The three-degree-of-freedom ankle joint prosthesis with a gear mechanism as claimed in claim 4, characterized in that: The prosthetic foot comprises: A tray (25), wherein the magnetic damping connection device is arranged on one surface of the tray (25); the output rod (38) is threadedly connected to the tray (25); A keel (26), wherein the keel (26) is connected to another surface of the tray (25); An elastic foot blade (27), wherein the elastic foot blade (27) is connected to the keel (26); A lower blade (28), wherein the lower blade (28) is connected to the keel (26). The prosthetic foot further comprises: A plantar pressure sensor (39) is arranged at the contact portion between the elastic foot blade and the ground.

6. The three-degree-of-freedom ankle joint prosthesis with a gear mechanism as claimed in claim 5, characterized in that: The keel (26) is provided with a receiving groove; The prosthetic foot further comprises: An inertial measurement unit (36), the inertial measurement unit (36) being arranged in the receiving groove; A gyroscope (37) is arranged at the rear end surface of the keel.

7. The three-degree-of-freedom ankle joint prosthesis with a gear mechanism as claimed in claim 6, characterized in that: A through hole is formed at the bottom of the prosthetic sleeve (14); The bottom plane of the prosthetic sleeve (14) is threadedly connected to six connecting posts (15); The internal thread of the connecting column is threadedly connected to the ball seat (16), and the ball seat (16) is hinged to the ball head rod (17).

8. The three-degree-of-freedom ankle joint prosthesis with a gear mechanism as claimed in claim 7, characterized in that: The magnetic damping connection device comprises a magnetic conductive layer (18), a steel cylinder (19), a magnetic seat (20), a spiral coil (29), a linear bearing (21), a conductor layer (22), a ball head rod (17), a ball head cover (23), a ball seat (16), and a connecting column (15); wherein: The magnetic conductive layer (18) is threadedly connected to the inner wall of the steel cylinder (19), the magnetic seat (20) is threadedly connected to the inner wall of the steel cylinder (19), the spiral coil (29) is stuck in the groove of the magnetic seat (20), the two ends of the magnetic seat (20) are gaskets (10) and linear bearings (21), the conductor layer (22) is threadedly connected to the ball head rod (17), and the ball head rod (17) drives the conductor layer (22) to move in the steel cylinder (19); the right end of the steel cylinder (19) is screwed to the ball head cover (23), the ball head of the ball head cover (23) is hinged to the ball seat (16), and the ball seat (16) is threadedly connected to the tray (25) through the connecting column (15).

9. The three-degree-of-freedom ankle joint prosthesis with a gear mechanism as claimed in claim 8, characterized in that: The two special-shaped gears (2) are distributed inside the artificial limb sleeve (14) at an angle of 60 degrees to each other, and the meshing planes of the two special-shaped gears (2) and the ball gear (1) are also at an angle of 60 degrees.

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