Powered Lower Limb Prosthesis Based on Variable-Stiffness Origami Mechanism

Abstract

The present invention provides a power-type lower limb prosthesis based on a variable stiffness origami mechanism, comprising: a prosthesis module and a power shoe module. The power shoe module includes an origami mechanism module, a sensing module, a power shoe drive motor, an upper bottom plate and a lower bottom plate; the origami mechanism module is fixedly arranged between the upper bottom plate and the lower bottom plate and jointly serves as the sole of the power shoe module. The sensing module is arranged on the lower bottom plate, and the drive end of the power shoe drive motor is connected to the upper bottom plate; a control module is further included, which obtains terrain signals through the sensing module. The control module controls the power shoe drive motor according to the terrain signals to drive the upper bottom plate to compress / stretch the origami mechanism module and adjust the stiffness of the origami mechanism module. The present invention can help the disabled perceive and adapt to different terrains by performing real-time stiffness transformation of the sole of the power shoe through the origami mechanism, and the presence of the origami mechanism can help the entire power assist device release energy stably and reduce the injuries of the disabled during movement in special scenarios.

Description

Technical Field

[0001] The present invention relates to the technical field of lower limb prostheses, and specifically, to a powered lower limb prosthesis based on a variable stiffness origami mechanism. Background Art

[0002] Lower limb prostheses can be divided into two categories: passive prostheses and intelligent powered prostheses. People with damaged or lost musculoskeletal systems use them as artificial devices to replace their original limbs, which play a very important role in the daily lives of disabled people. The comfort and safety of prostheses have a great impact on the daily lives of disabled people. Through literature research, there are currently problems such as excessive energy consumption, inconvenience in movement caused by asymmetry with healthy bodies, and inability to perceive terrain changes when disabled people wear traditional passive prostheses. With the development of technology, intelligent powered prostheses have emerged and have achieved certain development in recent years. Intelligent powered prostheses still cannot solve the problem of different perceptual experiences for different terrains after disabled people wear prostheses, and although wearing intelligent powered prostheses can reduce the energy loss of disabled people, some safety problems are also likely to occur. Therefore, providing an intelligent powered prosthesis that can enhance the comfort and safety of disabled people is an urgent problem to be solved.

[0003] In the Chinese patent document with the publication number CN207532466U, an energy storage foot is disclosed. When the user wears this device and makes cross-country movements such as going up stairs or jumping, the energy storage foot immediately releases energy after absorbing it, which will cause the user to receive a large thrust and even cause the user to fall. The above device will pose a great safety hazard to disabled people in their daily activities. Therefore, it is necessary to provide an intelligent powered prosthesis with higher safety, reliability, and comfort. Summary of the Invention

[0004] Aiming at the defects in the prior art, the purpose of the present invention is to provide a powered lower limb prosthesis based on a variable stiffness origami mechanism.

[0005] A powered lower limb prosthesis based on a variable stiffness origami mechanism according to the present invention includes: a prosthesis module and a power shoe module, and the end of the prosthesis module is rotatably connected to the power shoe module;

[0006] The power shoe module includes an origami mechanism module, a sensing module, a power shoe drive motor, an upper bottom plate, and a lower bottom plate; the origami mechanism module is fixedly arranged between the upper bottom plate and the lower bottom plate and jointly serves as the sole of the power shoe module, the sensing module is arranged on the lower bottom plate, and the drive end of the power shoe drive motor is connected to the upper bottom plate;

[0007] It further includes a control module that obtains terrain signals through the sensing module. The control module controls the assistive shoe drive motor according to the terrain signals, drives the upper base plate to compress / stretch the origami mechanism module, and adjusts the stiffness of the origami mechanism module.

[0008] Preferably, the prosthetic module includes an active knee joint and an active ankle joint. The active knee joint includes a knee joint drive motor and a knee joint protection housing connected to the knee joint drive motor. The active knee joint is located at the upper end of the prosthetic module. A limb connecting piece is provided at the upper end of the knee joint protection housing, and the limb connecting piece is used to connect to a real limb;

[0009] The active ankle joint includes an ankle joint drive motor and an ankle joint protection housing. The active ankle joint is located at the lower end of the prosthetic module. A shoe connecting piece is provided on the ankle joint protection housing, and the shoe connecting piece is used to connect to the assistive shoe module.

[0010] Preferably, the origami mechanism module is composed of a plurality of twisted towers arranged. Each twisted tower is formed by connecting the same origami segments to form a single-layer twisted tower, and a plurality of the single-layer twisted towers are stacked on top of each other.

[0011] Preferably, the sensing module includes force sensors. Multiple groups of force sensors are provided on the lower base plate. The control module judges the terrain environment according to the data collected by the force sensors, and adjusts the rigidity of the origami mechanism module according to the terrain environment to complete the adjustment of the variable stiffness of the shoe sole.

[0012] Preferably, the control module is located in the middle of the prosthetic module. The control module includes a microprocessor that receives and processes the information obtained by the sensing device, and processes the movements of the knee joint motor, the ankle joint motor, and the assistive shoe drive motor.

[0013] Preferably, the assistive shoe drive motor is fixedly arranged in the middle of the assistive shoe module. The drive end of the assistive shoe drive motor is fixedly connected to the upper base plate, and the assistive shoe drive motor is electrically connected to the control module.

[0014] Preferably, the assistive shoe module further includes a power supply module, and the power supply module is electrically connected to the sensing module and the assistive shoe drive motor.

[0015] Preferably, the upper base plate and the lower base plate are made of synthetic rubber material.

[0016] Preferably, a detachable buckle is provided between the upper base plate and the lower base plate. The upper base plate and the lower base plate are locked and unlocked through the detachable buckle, so as to install the origami mechanism module.

[0017] Preferably, the prosthetic module is made of aluminum alloy material.

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

[0019] 1. The present invention actively provides assistance for the disabled through the force-type prosthetic limb and the assistive shoe. The force sensor senses different terrain information, and then the stiffness of the sole of the assistive shoe is changed in real time through the origami mechanism to help the disabled perceive and adapt to different terrains. Moreover, the existence of the origami mechanism can help the entire assistive device release energy stably and reduce the injuries of the disabled during movement in special scenarios.

[0020] 2. While providing assistance to the knee joint and ankle joint of the prosthetic limb module, the assistive shoe can also provide power, realizing that all parts of the prosthetic limb are completely active and controllable, making the prosthetic limb more intelligent and controllable.

[0021] Other beneficial effects of the present invention will be elaborated in the specific implementation manner through the introduction of specific technical features and technical solutions. Those skilled in the art should be able to understand the beneficial technical effects brought by the said technical features and technical solutions through these introductions. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] By reading the following detailed description of the non-limiting embodiments with reference to the accompanying drawings, other features, objects, and advantages of the present invention will become more apparent:

[0023] Figure 1 It is a schematic diagram of the overall structure of the power-type lower limb prosthetic limb based on the variable-stiffness origami mechanism in the embodiment;

[0024] Figure 2 It is a front perspective schematic diagram of the assistive shoe module in the embodiment;

[0025] Figure 3 It is a schematic diagram of the natural state of a single twisted tower in the origami mechanism module in the embodiment;

[0026] Figure 4 It is a schematic diagram of the compressed state of a single twisted tower in the origami mechanism module in the embodiment;

[0027] Figure 5 It is a schematic diagram of the unfolding of a single origami segment in the origami mechanism module in the embodiment;

[0028] Figure 6 It is a schematic diagram of a single origami segment in the origami mechanism module in the embodiment;

[0029] Figure 7 It is a front schematic diagram of the prosthetic limb module in the embodiment.

[0030] Description of the reference numerals:

[0031] Active knee joint 1 Sensing module 8

[0032] Control module 2, power supply module 9

[0033] Active ankle joint 3, power-assisted shoe module 10

[0034] Power-assisted shoe drive motor 4, prosthetic module 11

[0035] Upper base plate 5, drive motor 12

[0036] Origami mechanism module 6, motor housing 13

[0037] Lower base plate 7 Specific implementation mode

[0038] The present invention will be described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several changes and improvements can still be made. These all belong to the protection scope of the present invention.

[0039] The present invention provides a power-assisted lower limb prosthetic based on a variable stiffness origami mechanism, which can be directly worn on the disabled limb, including: prosthetic module 11 and power-assisted shoe module 10. The prosthetic module 11 is a power-assisted prosthetic with two active joints, namely an active knee joint 1 and an active ankle joint 3, and a control module 2, and the active ankle joint 3 is rotationally connected to the power-assisted shoe module 10.

[0040] The assistive shoe module 10 includes an origami mechanism module 6, a sensing module 8, an assistive shoe drive motor 4, an upper base plate 5, and a lower base plate 7. The origami mechanism module 6 is fixedly arranged between the upper base plate 5 and the lower base plate 7, and together they serve as the sole of the assistive shoe module 10. The upper base plate 5 and the lower base plate 7 are made of synthetic rubber material. The sensing module 8 is arranged on the lower base plate 7, and the drive end of the assistive shoe drive motor 4 is connected to the upper base plate 5. The sensing module 8 obtains terrain signals, and the control module 2 controls the assistive shoe drive motor 4 according to the terrain signals, driving the upper base plate 5 to compress / stretch the origami mechanism module 6 and adjusting the stiffness of the origami mechanism module 6. The sensing module 8 is a force sensor for detecting different terrain signals. There are two groups of force sensors arranged on the lower base plate 7, one group is placed on the front half side and the other group is placed on the rear half side. During the walking process of the disabled person, the force sensors on the front and rear sides of the sole can transmit signals to the control module 2 after sensing different scene information. The control module 2 receives and processes the terrain signals sensed by the sensing module 8, and transmits the processed signal for adjusting the stiffness to the assistive shoe drive motor 4. The assistive shoe drive motor 4 adjusts the stiffness of the sole. To ensure uniform force on the sole, the assistive shoe drive motor 4 is fixedly arranged in the middle of the assistive shoe module 10. The drive end of the assistive shoe drive motor 4 is fixedly connected to the upper base plate 5, and the assistive shoe drive motor 4 is electrically connected to the control module 2. After receiving the signal from the control module 2, the assistive shoe drive motor 4 drives the upper base plate 5 to move up and down, thereby driving the origami mechanism module 6 to expand and contract, and further realizing the variable stiffness requirement of the assistive shoe module 10 in different scenarios. The assistive shoe module 10 further includes a power supply module 9, which is electrically connected to the sensing module 8 and the assistive shoe drive motor 4. The power supply module 9 is a lightweight battery placed on the upper side of the assistive shoe module 10 to supply power to the entire device.

[0041] The origami mechanism module 6 is composed of multiple twisted towers arranged. Each twisted tower is composed of the same origami segments. The reference diagram of the origami unit is Figure 6 , and they are connected in an octagonal pattern to form a single-layer twisted tower. Multiple such single-layer twisted towers are stacked on top of each other. During actual use, the number of twisted towers can be increased or decreased according to the adaptability of the disabled person to the powered prosthesis.

[0042] In a specific embodiment, as Figure 4 shown, it is the state after the two-layer twisted tower linearly contracts in the counterclockwise direction. The origami segment is folded from a rectangular paper, specifically referring to Figure 5As shown, the size of the rectangular paper determines the diameter and height of each octagon formed. Therefore, it must be determined according to the size and weight of the components such as the parts embedded in the prosthetic structure. Each tower layer is composed of 16 individual origami segments, specifically 8 origami units that make up the top octagon layer and 8 origami segments that support this layer. The movement of the origami mechanism module 6 is generated by the power-assisted shoe drive motor 4 driving the upper base plate 5. A single twisted tower can complete 4 motion forms of leftward rotational stretching / compression, rightward torsional stretching / compression, leftward bending, and rightward bending when there are enough layers. In this embodiment, two layers of twisted towers are used, and the movement direction is leftward stretching / compression. When the power-assisted shoe drive motor 4 pulls the upper base plate 5 upward, the twisted tower is stably stretched during leftward torsion, and the stiffness becomes smaller; when the power-assisted shoe drive motor 4 pushes the upper base plate 5 downward, the twisted tower is stably compressed during leftward torsion, and the stiffness becomes larger. The stiffness of the twisted tower is constantly changing during the stretching / compression process, which causes the stiffness of the power-assisted shoe sole to change, so as to achieve the purpose that the powered lower limb can perceive and adapt to different terrains.

[0043] The origami mechanism module 6 is different from the ordinary spring mechanism, and its stiffness changes with the change of the mechanism state (compression / stretching / torsion). The initial thickness of each twisted tower is t, and its stiffness coefficient k represents the ability of the origami to resist the stretching or compression of the tower layer. The initial stiffness coefficient of the origami shoe is k0, and the stiffness during the change process is λk0. It has been verified by experiments that when the state of the origami mechanism changes, λ changes non-linearly. During the compression process of the twisted tower, t slowly decreases, λ < 1, k decreases, and the stiffness shows a decreasing trend; during the stretching process, t slowly increases, λ > 1, k increases, and the stiffness shows an increasing trend. In the normal direction, the contact mechanics model of the origami structure of the prosthetic foot-ground interaction force can be approximated as the force on the foot spring and the foot damper. k TN is the stiffness of various terrains, k D is the overall identified stiffness, δ T and δ F are the deformations of the terrain and the foot respectively. δ is the sum of the two, expressed as: δ = F N / k D δ F +δ T = F N / k0 + F N / k TN . The mathematical expression of the equivalent stiffness relationship is: 1 / k D = 1 / k0 + 1 / k TN .

[0044] Refer to Figure 7As shown, the prosthetic module 11 includes an active knee joint 1 and an active ankle joint 3. The active knee joint 1 includes a drive motor 12 and a protective housing 13 connected to the knee joint drive motor. The active knee joint 1 is located at the upper end of the prosthetic module 11. A limb connecting member is provided at the upper end of the knee joint protective housing 13. The limb connecting member is used to connect to a real limb, facilitating the disabled to wear and replace the prosthetic limb.

[0045] The active ankle joint 3 includes a drive motor 12 and a protective housing 13. The active ankle joint 3 is located at the lower end of the prosthetic module 11. A shoe connecting member is provided on the ankle joint protective housing 13. The shoe connecting member is used to connect to the assistive shoe module 10, facilitating the wearing and replacement of the assistive shoe module 10. When the two motors 12 of the knee joint and the ankle joint are installed facing backward, during the control process, when the control curve of the knee joint motor 12 deviates from the target curve due to uncontrollable slight oscillation, it is easy to collide with the prosthetic limb, causing wear of the prosthetic limb and the motor. To reduce the wear of the hardware related to the drive motor 12 of the prosthetic module 11, the motor directions of the two active joints are installed as Figure 7 shown in the figure. In addition, installing the motor in this way can effectively prevent the prosthetic limb from hitting the human body when the control effect is not good enough, effectively reducing some safety problems of active prosthetic limbs. The control module 2 includes a microprocessor. The outer protective shell of the control module 2 is fixed between the active knee joint 1 and the active ankle joint 3, and is electrically connected to the two active joints of the prosthetic module 11, the assistive shoe drive motor 4, the sensing module 8, and the power supply module 9. The entire prosthetic module 11 is connected by an aluminum metal rod with adjustable telescopic length.

[0046] Detachable buckles are provided between the lower bottom plate 7 and the upper bottom plate 5 of the assistive shoe module 10, facilitating the disassembly and installation of the twisting tower. When the disabled wear the power-type lower limb prosthetic limb based on the variable stiffness origami mechanism, they can remove or increase the number of twisting towers according to their daily activity habits to adjust the variable stiffness ability of the assistive shoe and the adaptive force generated during assistance, start adapting from a smaller assistance, adjust the adaptation period of the disabled, and thus help them adapt to the assistive prosthetic limb more flexibly.

[0047] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying 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 construed as a limitation to the present application.

[0048] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A dynamic lower limb prosthesis based on a variable stiffness origami mechanism, characterized in that, Including: A prosthetic module (11) and an assistive shoe module (10), wherein the end of the prosthetic module (11) is rotatably connected to the assistive shoe module (10); The assistive shoe module (10) includes an origami mechanism module (6), a sensing module (8), an assistive shoe drive motor (4), an upper bottom plate (5), and a lower bottom plate (7); the origami mechanism module (6) is fixedly arranged between the upper bottom plate (5) and the lower bottom plate (7), and together with the upper bottom plate (5) and the lower bottom plate (7) serves as the sole of the assistive shoe module (10), the sensing module (8) is arranged on the lower bottom plate (7), and the drive end of the assistive shoe drive motor (4) is connected to the upper bottom plate (5); It further includes a control module (2), which obtains terrain signals through the sensing module (8), and the control module (2) controls the assistive shoe drive motor (4) according to the terrain signals to drive the upper bottom plate (5) to compress / stretch the origami mechanism module (6) and adjust the stiffness of the origami mechanism module (6); The origami mechanism module (6) is composed of multiple twisted towers arranged, and each twisted tower is formed by connecting multiple identical origami segments to form a single-layer twisted tower, and is stacked by multiple said single-layer twisted towers.

2. The powered lower limb prosthesis based on the variable stiffness origami mechanism according to claim 1, characterized in that, The prosthetic module (11) includes an active knee joint (1) and an active ankle joint (3), the active knee joint (1) includes a knee joint drive motor and a knee joint protection housing connected to the knee joint drive motor, the active knee joint (1) is located at the upper end of the prosthetic module (11), and a limb connector is arranged at the upper end of the knee joint protection housing, and the limb connector is used to connect to a real human limb; The active ankle joint (3) includes an ankle joint drive motor and an ankle joint protection housing, the active ankle joint (3) is located at the lower end of the prosthetic module (11), and a shoe connector is arranged on the ankle joint protection housing, and the shoe connector is used to connect to the assistive shoe module (10).

3. The powered lower limb prosthesis based on the variable stiffness origami mechanism according to claim 1, characterized in that The sensing module (8) includes force sensors, and multiple groups of force sensors are arranged on the lower bottom plate (7), and the control module (2) judges the terrain environment according to the data collected by the force sensors and adjusts the rigidity of the origami mechanism module (6) according to the terrain environment to complete the adjustment of the variable stiffness of the sole.

4. The powered lower limb prosthesis based on the variable stiffness origami mechanism according to claim 1, characterized in that, The control module (2) is located in the middle of the prosthetic module (11), and the control module (2) includes a microprocessor, and the microprocessor receives and processes the information obtained by the sensing device, and processes the movements of the knee joint motor, the ankle joint motor, and the assistive shoe drive motor (4).

5. The powered lower limb prosthesis based on the variable stiffness origami mechanism according to claim 1, wherein, The assistive shoe drive motor (4) is fixedly arranged in the middle of the assistive shoe module (10), the drive end of the assistive shoe drive motor (4) is fixedly connected to the upper bottom plate (5), and the assistive shoe drive motor (4) is electrically connected to the control module (2).

6. The powered lower limb prosthesis based on the variable stiffness origami mechanism according to claim 1, wherein The assistive shoe module (10) further includes a power supply module (9), and the power supply module (9) is electrically connected to the sensing module (8) and the assistive shoe drive motor (4).

7. The powered lower limb prosthesis based on the variable stiffness origami mechanism according to claim 1, wherein The upper bottom plate (5) and the lower bottom plate (7) are made of synthetic rubber material.

8. The power lower limb prosthesis based on the variable stiffness origami mechanism according to claim 1, characterized in that, A detachable buckle is arranged between the upper bottom plate (5) and the lower bottom plate (7), and the upper bottom plate (5) and the lower bottom plate (7) are locked and unlocked through the detachable buckle, so as to install the origami mechanism module (6).

9. The power lower limb prosthesis based on the variable stiffness origami mechanism according to claim 1, characterized in that, The prosthetic module (11) is made of aluminum alloy material.

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