Five-connecting-rod self-adaptive multi-mode prosthetic knee joint based on magnetorheological effect

Abstract

The invention belongs to the technical field of prosthetic knee joints, and particularly relates to a five-connecting-rod self-adaptive multi-mode prosthetic knee joint based on a magnetorheological effect, which comprises a motor, an output shaft of the motor is connected with an input shaft of a double-output speed reducer, and an output shaft of the double-output speed reducer is connected with a five-connecting-rod mechanism. According to the double-output speed reducer, the self-locking connecting rod is locked and released through the self-holding electromagnet, and the self-locking characteristic of the worm gear and the worm is combined, so that dynamic reconfiguration of the five-connecting-rod mechanism is achieved; the five-connecting-rod mechanism is switched between a four-connecting-rod mechanism and an equivalent single-shaft mechanism, so that the three working states of an active mode, a semi-active mode and a mixed mode are achieved, walking requirements in different environments are met, powerful functions are guaranteed, meanwhile, high reliability and low cost are achieved, and the optimal balance of performance and energy consumption is achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of prosthetic knee joints, and particularly relates to a five-link self-adaptive multi-mode prosthetic knee joint based on a magnetorheological effect. BACKGROUND

[0002] At present, the key to the rehabilitation of lower limb amputees lies in a prosthetic knee joint with excellent performance. An ideal prosthetic knee joint should be able to adapt to various activities such as walking, going up and down stairs, running, etc., and provide appropriate damping or power in different gait phases, so as to realize the stability and naturalness of gait.

[0003] The prosthetic knee joints in the prior art are mainly passive, active and semi-active. Passive prostheses (such as simple mechanical single-axis knee joints) have fixed damping and cannot adapt to changing road conditions, with limited functions. Active prostheses usually use motors for driving and can provide power, but have problems such as high power consumption, heavy weight and obvious noise. Semi-active prostheses (such as intelligent prostheses using magnetorheological fluid) realize intelligent control by adjusting damping, with lower energy consumption, and their structures are mostly single-axis or four-link mechanisms, which still have limitations in adaptability in complex environments.

[0004] In order to combine the advantages of active and passive prosthetic knee joints, some hybrid drive prosthetic knee joints are disclosed in the prior art. For example, domestic patents CN120363244A and CN211131562U disclose a scheme combining a motor and a damper. However, these devices usually have problems such as complex structure, cumbersome mode switching, etc. The complex structure leads to decreased reliability, increased weight and high cost, making many users hesitate. In addition, most designs fail to solve the key problem of how to optimize the kinematic characteristics of the mechanism in different working modes. For example, in the active mode requiring high power output, the mechanism fails to lock into the most stable state; and in the semi-active mode for power saving, its motion trajectory cannot be simplified to realize more reliable single-axis damping control. SUMMARY

[0005] The present application provides a five-link self-adaptive multi-mode prosthetic knee joint based on a magnetorheological effect.

[0006] To achieve the above purpose, the present application adopts the following technical scheme: A five-link self-adaptive multi-mode prosthetic knee joint based on the magnetorheological effect, comprising a motor, a motor mounting seat is fixedly installed at the lower end of the motor, a through hole is formed in the motor mounting seat, the motor mounting seat is fixedly installed on the upper surface of the box body of a double-output speed reducer, the output shaft of the motor is connected with the input shaft of the double-output speed reducer through the through hole, the output shaft of the double-output speed reducer is connected with a five-link mechanism, the five-link mechanism comprises a front link fixedly installed on the output shaft of the double-output speed reducer, the other end of the front link is hingedly connected with a lower link, the other end of the lower link is hingedly connected with a self-locking link, a self-holding electromagnet is fixedly installed at the right end of the inner side of the lower link, a self-locking hole corresponding to the slide rod on the self-holding electromagnet is formed on the self-locking link, the other ends of the two self-locking links are hingedly connected with a rear link, the other end of the rear link is hingedly connected with a pin shaft, the pin shaft is fixedly installed on the box body of the double-output speed reducer, a link bracket is fixedly installed on the left side of the upper end of the box body of the double-output speed reducer, a damping link is hingedly connected to the link bracket, the other end of the damping link is hingedly connected with the piston rod of a magnetorheological damper, and the shell of the magnetorheological damper is fixedly connected with the lower end of the lower link.

[0007] Further, the motor adopts an M3508 direct-current brushless motor.

[0008] Still further, the double-output speed reducer is a worm and gear mechanism.

[0009] Still further, the speed reduction ratio of the double-output speed reducer is 15:1, and the double-output speed reducer has a reverse self-locking characteristic.

[0010] Still further, the inner sides of the lower links are each provided with a bracket for installing a self-holding electromagnet.

[0011] Compared with the prior art, the present application has the following advantages: The present application ingeniously realizes the dynamic reconstruction of the five-link mechanism configuration through the locking and releasing of the self-locking link by the self-holding electromagnet and the self-locking characteristic of the worm and gear mechanism. In the active and hybrid modes, the knee joint is locked as a four-link mechanism optimized for motion trajectory, providing stable support and power; in the semi-active mode, the knee joint is equivalent to a simple single-axis mechanism, and only the magnetorheological damper provides variable damping, greatly reducing energy consumption, so that the prosthetic knee joint can adapt to various activity scenarios such as walking, going up and down stairs, and running. The present application integrates the advantages of active driving and semi-active damping control, so that it can automatically and flexibly switch to the optimal kinematic configuration in each working mode, thereby ensuring powerful function while having high reliability and low cost, achieving the best balance between performance and energy consumption. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 is the isometric view of the present application; Figure 2The axis drawing of the five-link mechanism of the present application; Figure 3 The sectional view of the present application; Figure 4 The axis drawing of the lower link and the magnetorheological damper of the present application; Figure 5 The axis drawing of the motor mounting seat of the present application; Figure 6 The axis drawing of the self-locking link of the present application.

[0013] In the figure, motor 1, motor mounting seat 2, through hole 201, double-output reducer 3, five-link mechanism 4, front link 401, lower link 402, bracket 4021, self-locking link 403, self-locking hole 4031, rear link 404, self-holding electromagnet 5, pin shaft 6, link bracket 7, damping link 8, magnetorheological damper 9. DETAILED DESCRIPTION

[0014] In order to further illustrate the technical scheme of the present application, the present application is further illustrated by examples below.

[0015] As Figures 1 to 6As shown, a five-bar adaptive multi-mode prosthetic knee joint based on magnetorheological effect includes a motor 1, which is an M3508 brushless DC motor. A motor mounting base 2 is fixedly mounted on the lower end of the motor 1. A through hole 201 is provided in the motor mounting base 2, which is fixedly mounted on the upper surface of the housing of a dual-output reducer 3. The output shaft of the motor 1 passes through the through hole 201 and connects to the input shaft of the dual-output reducer 3. The dual-output reducer 3 is a worm gear mechanism with a reduction ratio of 15:1. Having a reverse self-locking characteristic, the output shaft of the dual-output reducer 3 is connected to a five-bar linkage 4. This five-bar linkage serves as the main structure connecting the thigh support and the lower leg support. The five-bar linkage 4 includes a front link 401 fixed to the output shaft of the dual-output reducer 3. The other end of the front link 401 is hinged to a lower link 402, and the other end of the lower link 402 is hinged to a self-locking link 403. A self-holding electromagnet 5 is fixedly installed on the right end of the inner side of the lower link 402. The inner side of the lower link 402 is provided with mounting points for the self-holding electromagnet. The bracket 4021 of iron 5 has a self-locking hole 4031 on the self-locking connecting rod 403 corresponding to the sliding rod on the self-holding electromagnet 5. The other ends of the two self-locking connecting rods 403 are hinged to the rear connecting rod 404. The other end of the rear connecting rod 404 is hinged to the pin 6. The pin 6 is fixedly installed on the housing of the dual output reducer 3. The motor 1 and the dual output reducer 3 are integrated with the thigh bearing part to form an upper connecting rod. A connecting rod bracket 7 is fixedly installed on the upper left side of the housing of the dual output reducer 3. A resistance is hinged on the connecting rod bracket 7. The damping link 8 has its other end hinged to the piston rod of the magnetorheological damper 9, thereby converting the flexion and extension motion of the knee joint into the linear motion of the piston rod in the cylinder. The housing of the magnetorheological damper 9 is fixedly connected to the lower end of the lower link 402 and integrated into the calf support. The five-bar linkage 4 includes an upper link consisting of a motor 1 and a dual-output reducer 3 integrated with the thigh support, a lower link 402 fixed to the calf support, a front link 401 for connecting the upper link and the lower link, a self-locking link 403, and a rear link 404.

[0016] The working mode of this invention is as follows: Hybrid control of active and semi-active modes When the user needs to perform high-intensity activities such as brisk walking or climbing stairs, the system enters a hybrid control mode. At this time, the self-holding electromagnet 5 is energized, causing its sliding rod to extend and lock the self-locking linkage 403. The self-locking linkage 403 and the lower linkage 402 become integrated, transforming the original five-bar linkage 4 into a four-bar linkage with optimized motion trajectory. In this mode, the motor 1 and the magnetorheological damper 9 work together, with the motor 1 providing active power and the magnetorheological damper 9 providing adjustable damping, jointly ensuring strong power and stability for knee joint movement.

[0017] Active mode control When the user is navigating uneven, gently sloping, gravelly, or potholed terrain, and only needs motor 1 to provide power, the system enters active mode. In this mode, the magnetorheological damper 9 is not activated, and the self-holding electromagnet 5 remains extended. Therefore, the knee joint mechanism remains the four-bar linkage described above, with motor 1 operating independently. The dual-output reducer 3 drives the front linkage 401 to control knee joint movement. The self-locking characteristic of the dual-output reducer 3 prevents accidental bending of the knee joint under load.

[0018] Semi-active mode control When the user walks at a normal speed on flat ground, the system enters a semi-active mode to save energy. First, the self-holding electromagnet 5 is de-energized and retracts, releasing the lock on the self-locking linkage 403. Then, the motor 1 stops working. Due to the self-locking characteristic of the dual-output reducer 3, the output shaft fixed to the front linkage 401 is locked, making the front linkage 401 relatively fixed to the thigh support. At this time, the entire mechanism is reconstructed into a new four-bar linkage, and the instantaneous rotation center of this mechanism changes very little, which can be equivalent to a single-axis knee joint. When the user moves, the magnetorheological damper 9 works, and the magnetorheological damper 9 provides adjustable damping force to achieve gait control with low energy consumption.

[0019] The foregoing has shown and described the main features and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0020] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A five-bar self-adapting multi-mode prosthetic knee joint based on magneto-rheological effect, characterized in that, The application relates to a motor and a five-link mechanism, which comprises a motor (1), a motor mounting seat (2) fixedly arranged at the lower end of the motor (1), a through hole (201) arranged in the motor mounting seat (2), the motor mounting seat (2) being fixedly arranged on the upper surface of a box body of a double-output speed reducer (3), an output shaft of the motor (1) being connected with an input shaft of the double-output speed reducer (3) through the through hole (201), an output shaft of the double-output speed reducer (3) being connected with a five-link mechanism (4), the five-link mechanism (4) comprising a front link (401) fixedly arranged on the output shaft of the double-output speed reducer (3), the other end of the front link (401) being hingedly connected with a lower link (402), the other end of the lower link (402) being hingedly connected with a self-locking link (403), a self-retaining electromagnet (5) being fixedly arranged on the right end of the inner side of the lower link (402), a self-locking hole (4031) corresponding to a sliding rod on the self-retaining electromagnet (5) being arranged on the self-locking link (403), the other ends of two self-locking links (403) being hingedly connected with a rear link (404), the other end of the rear link (404) being hingedly connected with a pin shaft (6), the pin shaft (6) being fixedly arranged on the box body of the double-output speed reducer (3), a link bracket (7) being fixedly arranged on the left side of the upper end of the box body of the double-output speed reducer (3), a damping link (8) being hingedly arranged on the link bracket (7), the other end of the damping link (8) being hingedly connected with a piston rod of a magneto-rheological damper (9), and the shell of the magneto-rheological damper (9) being fixedly connected with the lower end of the lower link (402).

2. The five-bar self-adapting multi-mode MRF knee prosthesis according to claim 1, characterized in that, The motor (1) is an M 3508 direct-current brushless motor.

3. The five-bar self-adapting multi-mode MRF knee prosthesis according to claim 1, characterized in that, The double-output speed reducer (3) is a worm gear reducer.

4. The five-bar self-adapting multi-mode MRF knee prosthesis according to claim 3, characterized in that, The speed reduction ratio of the double-output speed reducer (3) is 15:1, and the double-output speed reducer (3) has reverse self-locking characteristics.

5. The five-bar self-adapting multi-mode MRF knee prosthesis according to claim 1, wherein, The inner side of the lower link (402) is provided with a bracket (4021) for mounting the self-retaining electromagnet (5).

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