A fully degrees-of-freedom bionic ankle-foot prosthesis

Abstract

The present invention relates to a full-degree-of-freedom bionic ankle-foot prosthesis, which includes a parallel drive module, and a limb connecting piece, a calf support rod, a heavy-duty linear support cylinder, and a foot plate module that are connected in sequence. Both ends of the heavy-duty linear support cylinder are connected to the calf support rod and the foot plate module through spherical joints respectively. The parallel drive module includes a plurality of drive units distributed outside the calf support rod. Each drive unit includes a linear drive mechanism, a first connecting rod, a second connecting rod, and a support column that are connected in sequence. The linear drive mechanism is fixed outside the calf support rod. The first connecting rod is arranged parallel to the calf support rod. One end of the first connecting rod is fixedly connected to the linear drive mechanism, and the other end is rotatably connected to the second connecting rod. The second connecting rod is rotatably connected to the support column, and the support column is fixedly connected to the foot plate module. Compared with the prior art, the present invention can achieve full-degree-of-freedom active movement imitating the human ankle joint and is applicable to walking on various complex road surfaces.

Description

Technical Field

[0001] The present invention relates to the technical field of bionic human prosthetics, and in particular to a full-degree-of-freedom bionic ankle-foot prosthetic limb. Background Art

[0002] In the case of lower limb amputation, installing a lower limb prosthetic limb becomes an effective means to restore standing and walking. Whether it is a thigh amputation or a calf amputation, a bionic ankle joint prosthetic limb is an essential component. Therefore, the research and development of bionic ankle joint prosthetic limbs has always been the technical focus and difficulty in the research of lower limb prosthetics.

[0003] Firstly, in terms of the degree of freedom of prosthetic limb movement: Considering the structural design and economic cost, the current mainstream ankle joint prosthetic limbs mainly focus on plantar flexion and dorsiflexion movements in the sagittal plane. Therefore, although the existing prosthetic limbs can meet the daily walking needs of most amputees, when encountering non-smooth road surfaces such as grasslands and pebble roads, problems such as obvious compensatory movements in the walking gait of amputees and a decrease in walking speed will occur.

[0004] Secondly, in terms of the power design of prosthetic limbs: Ankle joint prosthetic limbs can be divided into passive prosthetic limbs, active prosthetic limbs, and hybrid passive-active prosthetic limbs. Most of the traditional ankle joint prosthetic limbs on the market today are only passive prosthetic limbs, which have a simple structure and a low price, but do not contain a power mechanism. Although energy can be stored through springs, pneumatic cylinders or hydraulic cylinders to provide a certain amount of walking assistance, due to its uncontrollability, it leads to uncoordinated gait of amputee patients and requires more physical energy consumption. With the development of intelligent technology, active prosthetic limbs have developed rapidly. Active prosthetic limbs mainly sense their motion states through sensors, and a microprocessor controls the output power of a micro high-torque motor. However, since the entire motion process is in an active state and requires a large amount of energy, the requirements for batteries and motors of ankle joint prosthetic limbs are relatively high, resulting in a relatively large volume and mass of ankle joint prosthetic limbs, which hinders the movement of amputee patients.

[0005] In addition, during the movement of both passive and active prosthetic limbs, due to the too-rigid sole plate, the phenomenon of toe kicking the ground easily occurs, resulting in a reduced response speed during the swing phase of the prosthetic limb and affecting its use experience. Summary of the Invention

[0006] The purpose of the present invention is to overcome the defects of the above-mentioned existing technologies and provide a full-degree-of-freedom bionic ankle-foot prosthetic limb.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] A full-degree-of-freedom bionic ankle-foot prosthesis includes a parallel drive module, and a limb connecting member, a calf support rod, a heavy-duty linear support cylinder, and a foot plate module connected in sequence. Both ends of the heavy-duty linear support cylinder are connected to the calf support rod and the foot plate module through spherical joints respectively. The parallel drive module includes multiple drive units distributed on the outside of the calf support rod. Each drive unit includes a linear drive mechanism, a first connecting rod, a second connecting rod, and a support column connected in sequence. The linear drive mechanism is fixed on the outside of the calf support rod. The first connecting rod is arranged parallel to the calf support rod. One end of the first connecting rod is fixedly connected to the linear drive mechanism, and the other end is rotatably connected to the second connecting rod. The second connecting rod is rotatably connected to the support column, and the support column is fixedly connected to the foot plate module.

[0009] Further, a plurality of sliding long shaft holes are distributed on the outside of the calf support rod. The first connecting rod passes through the sliding long shaft holes and can move up and down along the sliding long shaft holes under the drive of the linear drive mechanism.

[0010] Further, the middle section of the first connecting rod is an elastic connecting member.

[0011] Further, both ends of the second connecting rod are connected to the first connecting rod and the support column through spherical joints.

[0012] Further, the foot plate module includes a mid-rear foot plate and a front foot plate. The two sides of the front foot plate are hinged to the mid-rear foot plate, so that the front foot plate can be turned up around the mid-rear foot plate.

[0013] Further, one end of the heavy-duty linear support cylinder is connected to the upper end face of the heel of the mid-rear foot plate.

[0014] Further, the foot plate module further includes a return spring. The mid-rear foot plate is provided with a rear foot mounting groove facing the front foot plate. The return spring is located in the rear foot mounting groove, with one end connected to the mid-rear foot plate and the other end connected to the front foot plate.

[0015] Further, the front foot plate is provided with a front foot mounting groove facing the mid-rear foot plate. One end of the return spring is inserted into the front foot mounting groove and then connected to the front foot plate.

[0016] Further, the parallel drive module includes four drive units, which are symmetrically distributed in pairs on the front side and the rear side of the calf support rod.

[0017] Further, the limb connecting member and the calf support rod are detachably connected.

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

[0019] 1. Ensure the basic load capacity through the calf support rod and the heavy-duty linear support cylinder, and then drive the foot plate module to move through the parallel drive module. Thus, the full-degree-of-freedom active movement of the humanoid ankle joint can be achieved. It can not only perform plantar flexion, dorsiflexion, inversion and eversion of the foot plate module, but also interact with the ground flexibly in any direction, and is applicable to walking on various complex road surfaces.

[0020] 2. A sliding long-axis hole is provided on the outer side of the calf support rod to improve the movement stability of the parallel drive module; at the same time, the middle section of the first connecting rod is an elastic connecting piece, enabling it to better adapt to the ground conditions.

[0021] 3. The foot plate module is designed as a combined flexible structure of the mid-rear foot plate and the front foot plate. When the foot plate leaves the ground, the front foot plate turns up, so that the toes can quickly leave the ground. This process is similar to the bone movement change of the human foot during the toe-off period, which can effectively avoid the phenomenon of toe dragging and improve the response speed of the prosthesis swing period. Brief Description of the Drawings

[0022] Figure 1 It is a schematic structural diagram of the present invention.

[0023] Figure 2 It is a schematic cross-sectional view of the present invention.

[0024] Figure 3 It is a schematic side view of the present invention.

[0025] Reference Numerals: 1. Parallel drive module, 11. Drive unit, 111. Linear drive mechanism, 112. First connecting rod, 112a. Elastic connecting piece, 113. Second connecting rod, 114. Support column, 2. Limb connecting piece, 3. Calf support rod, 31. Sliding long-axis hole, 4. Heavy-duty linear support cylinder, 5. Foot plate module, 51. Mid-rear foot plate, 511. Rear foot mounting groove, 52. Front foot plate, 521. Front foot mounting groove, 53. Return spring. Detailed Embodiment

[0026] The present invention will be described in detail below with reference to the drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and gives the detailed implementation manner and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0027] As Figure 1As shown in the figure, this embodiment provides a fully - degrees - of - freedom bionic ankle - foot prosthesis, which includes a limb connector 2, a calf support rod 3, a heavy - duty linear support cylinder 4, a foot plate module 5, and a parallel - drive module 1. The limb connector 2 is used to connect with the amputated limb of the human body. The calf support rod 3 is vertically and detachably installed at the bottom of the limb connector 2, and the connection method can adopt the conventional method. In this embodiment, after the top of the calf support rod 3 is inserted into the bottom mounting hole of the limb connector 2, it is locked by a clamping block. The heavy - duty linear support cylinder 4 is installed at the bottom of the calf support rod 3, and the bottom of the heavy - duty linear support cylinder 4 is connected to the foot plate module 5. The parallel - drive module 1 includes four drive units 11 distributed outside the calf support rod 3, and the bottom ends of the drive units 11 are connected to the foot plate module 5. Thus, the parallel - drive module 1 can realize the attitude of the foot plate module 5 to be adaptively adjusted according to the road conditions. For the large - torque demand of the joint in the middle of the stance phase, the heavy - duty linear support cylinder 4 is used in cooperation with the parallel - drive module 1 to achieve the transition between the front and rear stance phases, effectively saving the overall energy consumption during the movement of the prosthesis.

[0028] As Figure 2 shown, the heavy - duty linear support cylinder 4 uses a commercially available air cylinder or oil cylinder. The upper and lower ends of the heavy - duty linear support cylinder 4 are spherical heads, which respectively connect to the spherical grooves at the bottom of the calf support rod 3 and the spherical grooves on the top surface of the foot plate module 5 to form a spherical - joint connection. This structure enables the foot plate module 5 to have a full - degrees - of - freedom movement range.

[0029] As Figure 2 and Figure 3As shown in the figure, the calf support rod 3 includes two upper and lower parts. The upper part has a thinner diameter, and the lower part has a thicker diameter, forming a stepped structure. Four vertical sliding long-axis holes 31 are distributed on the outer circle of the protruding lower part. Each driving unit 11 includes a linear driving mechanism 111, a first connecting rod 112, a second connecting rod 113, and a support column 114 connected in sequence from top to bottom. The support column 114 is vertically fixed on the foot plate module 5. The linear driving mechanism 111 can use commercially available motors, cylinders, or oil cylinders, and there is no specific limitation; the linear driving mechanisms 111 are all fixed at the stepped structure. The upper end of the first connecting rod 112 is connected to the telescopic end of the direct driving mechanism, passes through the sliding long-axis hole 31 in the middle, the lower end is rotatably connected to one end of the second connecting rod 113, and the other end of the second connecting rod 113 is rotatably connected to the top of the support column 114. The second connecting rod 113 adopts a double-sided ball groove connecting body, and the lower end of the first connecting rod 112 and the top of the support column 114 are both spherical structures, which are embedded in the double-sided ball grooves to form a spherical joint. The four driving units 11 are symmetrically distributed in pairs on the front and rear sides of the calf support rod 3, and are equally spaced at an angle. The two second connecting rods 113 on the front side are parallel to each other and inclined forward, and the two second connecting rods 113 on the rear side are parallel to each other and inclined backward. Thus, when the linear driving mechanism 111 drives the first connecting rod 112 to move up and down along the sliding long-axis hole 31, the first connecting rod 112 drives the foot plate module 5 to change angles in all directions through the second connecting rod 113 and the support column 114, realizing full-degree-of-freedom movement. The kinematic and dynamic models can be used to establish an analytical expression for the motion mapping relationship between the posture of the foot plate module 5 and the movement of the driving unit 11, that is, by controlling the position and thrust changes of the four driving units 11, the movement and composite-direction movement state control of the foot plate unit in three directions of plantar flexion / dorsiflexion, internal rotation / external rotation, and adduction / abduction can be achieved.

[0030] In this embodiment, the middle section of the first connecting rod 112 is an elastic connecting piece 112a, which can specifically adopt a spring, so that the parallel driving module 1 can have a certain buffer and can better adapt to various ground road conditions.

[0031] In this embodiment, the foot plate module 5 includes a mid-rear foot plate 51 and a front foot plate 52. The rear ends on both sides of the front foot plate 52 are hinged to the mid-rear foot plate 51, enabling the front foot plate 52 to fold upward around the mid-rear foot plate 51. The foot plate module 5 further includes a return spring 53. The mid-rear foot plate 51 is provided with a rear foot mounting groove 511 facing the front foot plate 52. The return spring 53 is located in the rear foot mounting groove 511, with one end connected to the mid-rear foot plate 51 and the other end connected to the front foot plate 52. Thus, during the movement of the prosthetic limb, when the tip of the foot plate module 5 is about to leave the ground, the front foot plate 52 folds upward under the load of the leg, and the return spring 53 is stretched. By virtue of the rapid flexion movement characteristic of the residual limb knee joint, the tip of the foot quickly leaves the ground. This process is similar to the skeletal movement change of the human foot during the toe-off phase. When the tip of the foot leaves the ground, the stretched return spring 53 will promptly push the front foot plate 52 back to its original position.

[0032] In this embodiment, one end of the heavy-duty linear support cylinder 4 is connected to the upper end surface of the heel part of the mid-rear foot plate 51. During the stance phase of the prosthetic limb, the heavy-duty linear support cylinder 4 that is always in a compressed state can be used to ensure that the leg load can be transmitted to the mid-rear foot plate 51 through the calf rod, which can not only improve the load-bearing capacity of the prosthetic limb but also enhance the joint safety performance.

[0033] In another embodiment, the front foot plate 52 is provided with a front foot mounting groove 521 facing the mid-rear foot plate 51. One end of the reset spring is inserted into the front foot mounting groove 521 and then connected to the front foot plate 52, improving the installation stability of the reset spring.

[0034] In summary, this embodiment comprehensively considers the flexibility and active movement characteristics of the ankle joint prosthetic limb, and proposes a humanoid ankle joint that realizes full-degree-of-freedom movement through a parallel drive mechanism, and adds a front foot plate 52 to achieve a rapid swing when the tip of the foot leaves the ground. Among them, the parallel drive module 1 can adaptively adjust the posture of the ankle joint according to the road conditions. For the large torque requirement of the joint during the mid-stance phase, the transition between the front and rear stance phases is realized through a pure mechanical structure of the secondary support, avoiding excessive consumption of system energy.

[0035] The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations based on the concept of the present invention without creative labor. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field of the present invention through logical analysis, reasoning, or limited experiments based on the concept of the present invention on the basis of the prior art should fall within the protection scope determined by the claims.

Claims

1. A fully - degree - of - freedom bionic ankle - foot prosthesis, characterized in that, It includes a parallel drive module (1), as well as a limb connecting piece (2), a calf support rod (3), a heavy-duty linear support cylinder (4), and a foot plate module (5) connected in sequence. Both ends of the heavy-duty linear support cylinder (4) are connected to the calf support rod (3) and the foot plate module (5) through spherical joints respectively. The parallel drive module (1) includes a plurality of drive units (11) distributed on the outside of the calf support rod (3). Each drive unit (11) includes a linear drive mechanism (111), a first connecting rod (112), a second connecting rod (113), and a support column (114) connected in sequence. The linear drive mechanism (111) is fixed on the outside of the calf support rod (3). The first connecting rod (112) is arranged parallel to the calf support rod (3). One end of the first connecting rod (112) is fixedly connected to the linear drive mechanism (111), and the other end is rotatably connected to the second connecting rod (113). The second connecting rod (113) is rotatably connected to the support column (114). The support column (114) is fixedly connected to the foot plate module (5); The foot plate module (5) includes a mid-rear foot plate (51) and a front foot plate (52). The two sides of the front foot plate (52) are hinged to the mid-rear foot plate (51), enabling the front foot plate (52) to turn upward around the mid-rear foot plate (51); One end of the heavy-duty linear support cylinder (4) is connected to the upper end face of the heel part of the mid-rear foot plate (51); The foot plate module (5) further includes a return spring (53). The mid-rear foot plate (51) is provided with a rear foot mounting groove (511) facing the front foot plate (52). The return spring (53) is located in the rear foot mounting groove (511), with one end connected to the mid-rear foot plate (51) and the other end connected to the front foot plate (52); The front foot plate (52) is provided with a front foot mounting groove (521) facing the mid-rear foot plate (51). One end of the return spring (53) is inserted into the front foot mounting groove (521) and then connected to the front foot plate (52).

2. The fully degrees-of-freedom bionic ankle-foot prosthesis according to claim 1, wherein A plurality of sliding long shaft holes (31) are distributed on the outside of the calf support rod (3). The first connecting rod (112) passes through the sliding long shaft holes (31) and can move up and down along the sliding long shaft holes (31) under the drive of the linear drive mechanism (111).

3. The fully - degree - of - freedom bionic ankle - foot prosthesis according to claim 2, wherein, The middle section of the first connecting rod (112) is an elastic connecting piece (112a).

4. The fully degrees-of-freedom bionic ankle-foot prosthesis according to claim 1, characterized in that, Both ends of the second connecting rod (113) are connected to the first connecting rod (112) and the support column (114) through spherical joints.

5. The fully degrees-of-freedom bionic ankle-foot prosthesis according to claim 1, characterized in that, The parallel drive module (1) includes four drive units (11), which are symmetrically distributed in pairs on the front side and the rear side of the calf support rod (3).

6. The fully degrees-of-freedom bionic ankle-foot prosthesis according to claim 1, wherein The limb connecting piece (2) and the calf support rod (3) are detachably connected.

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