An intelligent foot and ankle prosthesis based on human structure and motion bionics

Abstract

An intelligent foot and ankle prosthesis based on human structure and motion simulation, including a heel profiling structure, the heel profiling structure is connected with a talus profiling structure, the talus profiling structure is connected with a foot sole profiling structure, the heel profiling structure and the foot sole profiling structure are installed with compression springs at the ends; the talus profiling structure is connected with one end of an Achilles tendon profiling structure, the other end of the Achilles tendon profiling structure is connected with a ball screw sliding block, the ball screw sliding block is fixed with a ball screw nut, the ball screw is fixed on a tibia profiling structure through screw bases and screw top fixing blocks at both ends, the tibia profiling structure is fixed with a prosthesis receiving cavity connecting block at the top end; the ball screw is driven by a motor, the tibia profiling structure and the talus profiling structure constitute a rolling joint connected by a fixed spring; the present application has the characteristics of simple and compact structure, good human motion fitting characteristics, excellent motion effect, energy saving, etc., and can be widely applied.

Description

Technical Field

[0001] This invention relates to the field of rehabilitation equipment technology, and in particular to an intelligent foot and ankle prosthesis based on human body structure and movement bionics. Background Technology

[0002] With the continuous growth of the population, natural disasters, traffic accidents, and other factors leading to an increasing proportion of amputees, wearing appropriate prostheses is an effective measure to help amputees reintegrate into society and daily life. The research and development of prostheses has a huge market and social demand. For tibial amputees, wearing foot and ankle prostheses is a reliable way to help them achieve normal daily walking and activity functions.

[0003] With the continuous development of the field of lower limb prostheses, compared with traditional passive and non-powered foot and ankle prostheses, active intelligent ankle prostheses have the characteristics of good stability and diversified functions. They can be designed with personalized solutions according to the amputee's condition. The research on intelligent foot and ankle prostheses has received increasing attention from scholars at home and abroad.

[0004] Currently, passive, unpowered ankle prostheses lack a drive unit, requiring the patient to rely on the strength of their residual limb for movement. This makes it difficult to achieve a natural and orderly gait, leading to user fatigue and difficulty in compensating for lost motor function in amputees. Furthermore, they are ill-suited to adapting to the ever-changing and complex terrain (Au, S., M. Berniker and H. Herr, Powered ankle-foot prosthesis to assist level-ground and stair-descent gaits. Neural Networks the Official Journal of the International Neural Network Society, 2008. 21(4): p. 654-666.). With the continuous improvement of economic and living standards, people's needs are no longer limited to bulky passive prostheses, and more and more scholars are investing in the research of intelligent prostheses. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention aims to provide an intelligent foot and ankle prosthesis based on human body structure and movement bionics, which has the characteristics of simple and compact structure, good human movement matching characteristics, excellent movement effect, and energy saving, and can be widely promoted and applied.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A smart foot and ankle prosthesis based on human body structure and movement biomimicry includes a heel-shaped structure 1, a talus-shaped structure 2 connected to the heel-shaped structure 1, a foot-shaped structure 4 connected to the talus-shaped structure 2, and compression springs 3 installed at the ends of the heel-shaped structure 1 and the foot-shaped structure 4; one end of the talus-shaped structure 2 is connected to the Achilles tendon-shaped structure 5, and the other end of the Achilles tendon-shaped structure 5 is connected to a ball screw slider 7; a ball screw nut 8 is fixed on the ball screw slider 7; both ends of the ball screw 9 are fixed to the tibia-shaped structure 13 through a screw base 6 and a screw top fixing block 10; a ball screw support rod 11 is installed between the screw base 6 and the screw top fixing block 10; the ball screw slider 7 is guided by the ball screw support rod 11; and a prosthesis receiving cavity connecting block 19 is fixed at the top of the tibia-shaped structure 13.

[0008] The ball screw 9 is driven by a motor 12, which is fixed to the tibial contour structure 13 via a motor mounting bracket 14. The tibial contour structure 13 and the talus contour structure 2 form a rolling joint, which is connected by four fixed springs 16.

[0009] The lateral restraint is achieved by the protrusion design of the talus mimicry structure 2 and the concave design corresponding to the tibial mimicry structure 13, ensuring that the rolling surface of the rolling joint formed by the tibial mimicry structure 13 and the talus mimicry structure 2 will not slide laterally.

[0010] The heel-shaped structure 1 and the foot-shaped structure 4, in conjunction with the compression spring 3, store and release energy during normal gait walking through compression deformation. The heel-shaped structure 1 and the foot-shaped structure 4 simulate the storage and release of energy by the tendons around the arch of the foot and the ankle joint.

[0011] The output shaft of the motor 12 is connected to a small pulley 17, which is connected to a large pulley 18 via a synchronous belt 20. The large pulley 18 is connected to the input end of the ball screw 9.

[0012] The rolling surfaces of the tibia mimicry structure 13 and the talus mimicry structure 2 are obtained by conducting biomimetic research and analysis on the human ankle joint, establishing a three-dimensional model of the human ankle joint surface, extracting key contact points of the joint and performing polynomial fitting to obtain its joint trajectory curve, and fixing the spring 16 to ensure that the rolling surfaces are always in contact. At the same time, the specific motion trajectory of the talus mimicry structure 2 is output by defining the shape of the rolling surface during the design process.

[0013] The motor 12 captures the motor speed and acceleration information through the encoder 15, and then adjusts the motor speed to ensure that the ankle joint rotation amplitude and speed match the walking speed. The motor 12 selects the stroke according to the size of the toe stroke and adjusts the forward and reverse rotation of the motor 12 according to the dorsiflexion and plantarflexion state of the ankle joint.

[0014] The tibial prosthetic structure 13 is provided with a prosthesis socket fixing block 19 connected to the prosthesis socket. The prosthesis socket fixing block 19 can be replaced according to different usage requirements, thereby achieving fine adjustment of the height of the patient's affected limb. The foot prosthetic structure 4 has a U-shaped hole at the end of the connection point, which can be adjusted back and forth to achieve appropriate adjustment of the size of the patient's entire foot.

[0015] The heel contouring structure 1 and the foot contouring structure 4 are designed in a personalized manner based on the height of the human foot arch and the curvature characteristics, so as to achieve elastic deformation close to that of the human foot.

[0016] The motor 12 adopts an electromyography (EMG) signal control mode. By analyzing the patient's movement intention through EMG signals, the working conditions of the activity site where the patient is located are determined. At the activity site, EMG signals and ranging radar control are used to switch control modes under different working conditions.

[0017] The beneficial effects of this invention are:

[0018] This invention conducts biomimetic research and analysis on the human ankle joint to obtain its joint trajectory curve, and uses this trajectory curve to design the rolling surface, thereby designing a foot and ankle prosthesis mechanism, resulting in a biomimetic intelligent foot and ankle prosthesis with a simple and compact structure, good human movement coordination characteristics, excellent movement effect, and energy saving.

[0019] Using an electric motor as the power source and driven by a synchronous belt, the structure is compact. The stroke is selected according to the size of the human toe travel, and the forward and reverse rotation of the motor is adjusted according to the dorsiflexion and plantarflexion state of the ankle joint, which significantly improves the stability and functionality of the ankle prosthesis.

[0020] Personalized designs are made based on the patient's height, arch height, curvature characteristics, and foot size to achieve elastic deformation close to that of the human foot and fine-tuning of the ankle prosthesis height, thereby enhancing product adaptability and improving the product's practical effect.

[0021] The method adopts electromyography (EMG) signal control mode. By analyzing the patient's movement intention through EMG signals, the working conditions of the activity site are determined. At the activity site, EMG signal control is used to switch control modes under different working conditions. The introduction of intelligent control can efficiently compensate for the motor function of patients with ankle defects. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0023] Figure 2 This is a schematic diagram of the heel contouring structure of the present invention.

[0024] Figure 3 This is a schematic diagram of the foot-shaped structure of the present invention.

[0025] Figure 4 This is a schematic diagram of the talus-shaped structure and its rolling surface of the present invention.

[0026] Figure 5 This is a schematic diagram of the Achilles tendon contour structure of the present invention.

[0027] Figure 6 This is a schematic diagram of the ball screw slider structure of the present invention.

[0028] Figure 7 This is a schematic diagram of the ball screw nut structure of the present invention.

[0029] Figure 8 This is a schematic diagram of the tibial contour structure and its rolling surface of the present invention.

[0030] Figure 9 This is a schematic diagram of the motor drive mechanism of the present invention. Detailed Implementation

[0031] The technical solution of the present invention will be further described and illustrated in detail below with reference to the accompanying drawings and embodiments. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0032] Reference Figure 1 A smart foot and ankle prosthesis based on human body structure and movement biomimicry includes a heel-shaped structure 1, a talus-shaped structure 2 connected to the heel-shaped structure 1, a foot-shaped structure 4 connected to the talus-shaped structure 2, and compression springs 3 installed at the ends of the heel-shaped structure 1 and the foot-shaped structure 4; the talus-shaped structure 2 is connected to one end of the Achilles tendon-shaped structure 5 via a bearing, and the other end of the Achilles tendon-shaped structure 5 is connected to a ball screw slider 7 via a bearing; a ball screw nut 8 is fixed on the ball screw slider 7; the two ends of the ball screw 9 cooperating with the ball screw nut 8 are fixed to the tibia-shaped structure 13 via a screw base 6 and a screw top fixing block 10; a ball screw support rod 11 is installed between the screw base 6 and the screw top fixing block 10; the ball screw slider 7 is guided by the ball screw support rod 11; and a prosthesis receiving cavity connecting block 19 is fixed at the top of the tibia-shaped structure 13.

[0033] The ball screw 9 is connected to the screw base 6 and the top fixing block 10 of the screw via bearings and is driven by the motor 12. The motor 12 is fixed to the tibial contour structure 13 via the motor fixing bracket 14. The tibial contour structure 13 and the talus contour structure 2 form a rolling joint, which is connected by four fixed springs 16 to provide contact force for the rolling surface.

[0034] Reference Figure 2 The heel contouring structure 1 is provided with six bolt mounting holes that connect to the talus contouring structure 2, as well as the first positioning post 21 of the compression spring 3.

[0035] Reference Figure 3 To facilitate the front-to-back adjustment of the foot contour structure 4 and achieve appropriate adjustment of the patient's foot size, U-shaped bolt connection holes are provided on the foot contour structure 4.

[0036] Reference Figure 4 The talus-shaped structure 2 has six bolt mounting holes at its lower front end that connect to the heel-shaped structure 1. The talus-shaped structure 2 has a grooved cylindrical connecting boss 23 at its upper front end that fixes the spring 16. The grooved cylindrical connecting boss 23 has a first rolling surface 22. To facilitate application and promotion, biomimetic research and analysis of the human ankle joint are conducted to obtain its joint trajectory curve. The first rolling surface 22 is designed with this trajectory curve as the core. The first rolling surface 22 is a single, symmetrical structure with a boss structure of the same curvature. The talus-shaped structure 2 has a second positioning post 25 at its lower rear end that compresses the spring 3. The talus-shaped structure 2 has bolt mounting holes at its upper rear end that connect to the U-shaped bolt connecting holes on the foot-shaped structure 4. The talus-shaped structure 2 has a square boss 24 at its upper end that connects to the ball screw slider 7 for mounting bearings.

[0037] Reference Figure 5 To improve the usability of the product and realize the power transmission of the rolling joint between the tibia mimicry structure 13 and the talus mimicry structure 2, one end of the Achilles tendon mimicry structure 5 is connected to the talus mimicry structure 2 through a bearing, and the other end is connected to the ball screw slider 7 through a bearing. The bearing connection effectively reduces the friction during the rotation of the Achilles tendon mimicry structure 5. The connection method is simple and reliable.

[0038] Reference Figures 6-7 The ball screw nut 8 is fixed on the ball screw slider 7 by bolt connection, and is fixed through six bolt holes 29 to ensure reliability. In order to increase the dexterity of the Achilles tendon contour structure 5 during movement, four bearings are used when connecting with the ball screw slider 7, and four bearing holes 26 are designed side by side. In order to ensure the stable and reliable operation of the ball screw 9, two guide holes 27 are designed on the ball screw slider 7 for assembling the ball screw support rod 11.

[0039] Reference Figure 8 A biomimetic study and analysis of the human ankle joint was conducted to obtain its joint trajectory curve. Based on this trajectory curve, the second rolling surface 30 of the lower part of the tibial mimicry structure 13 was designed. The second rolling surface 30 is designed with a concave surface 31. The second rolling surface 30 cooperates with the first rolling surface 22. The boss structure on the first rolling surface 22 cooperates with the concave surface 31 designed on the second rolling surface 30 to ensure the stability of the rolling joint operation.

[0040] The heel-shaped structure 1 and the foot-shaped structure 4, through compression deformation in conjunction with the compression spring 3, store and release energy during normal gait walking. By utilizing the heel-shaped structure 1 and the foot-shaped structure 4 to simulate the tendons around the arch of the foot and ankle joint to store and release energy, the work done is effectively reduced, and the physical exertion on the patient is reduced.

[0041] Reference Figure 9 To improve motion transmission efficiency and ensure accurate transmission ratio, a transmission mechanism consisting of a motor 12, a small pulley 17, a large pulley 18, and a synchronous belt 20 is used. The small pulley 17 is connected to the output shaft of the motor 12, and the small pulley 17 is connected to the large pulley 18 via the synchronous belt 20. The large pulley 18 is connected to the input end of the ball screw 9. The small pulley 17 drives the large pulley 18, increasing transmission efficiency and reducing energy consumption. The stroke of the motor 12 is selected based on the actual trajectory curve of the foot movement. The motor 12 captures the motor speed and acceleration information through the encoder 15, and then adjusts the motor speed to ensure the matching of ankle joint rotation amplitude and speed with walking speed. The motor 12 selects the stroke according to the size of the toe travel, and adjusts the forward and reverse rotation of the motor 12 according to the dorsiflexion and plantarflexion state of the ankle joint, significantly improving the stability and functionality of the ankle prosthesis.

[0042] The heel contouring structure 1 and the foot contouring structure 4 are designed in a personalized manner based on the height of the human foot arch and the curvature characteristics, so as to achieve elastic deformation close to that of the human foot.

[0043] The motor 12 adopts an electromyographic signal control mode. By analyzing the patient's movement intention through electromyographic signals, the working conditions of the activity site where the patient is located are determined. At the activity site, electromyographic control is used to switch control modes under different working conditions. The introduction of intelligent control can efficiently compensate for the movement function of patients with ankle defects.

[0044] The working principle of this invention is as follows:

[0045] The output shaft of motor 12 is connected to small pulley 17, which drives ball screw large pulley 18 through synchronous belt 20, causing ball screw 9 to rotate. Under the rotation of ball screw 9, ball screw slider 7 reciprocates on ball screw 9. The talus profiling component 2 rolls along the first rolling surface 22 under the pushing action of Achilles tendon profiling structure 5. The rolling joint prevents lateral sliding by cooperating with the concave surface of tibial profiling structure 13 through the protrusion of the rolling surface of talus profiling component 2. The heel profiling structure 1 and the foot profiling structure 4 achieve effective dorsiflexion and plantarflexion movements under the action of the rolling joint.

[0046] The above embodiments are only used to illustrate the present invention and are not intended to limit the present invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also fall within the scope of the present invention, and the protection scope of the present invention should be defined by the claims.

Claims

1. An intelligent foot and ankle prosthesis based on human body structure and motion biomimicry, characterized in that: The structure includes a heel-shaped structure (1), a talus-shaped structure (2) connected to the heel-shaped structure (1), a foot-shaped structure (4) connected to the talus-shaped structure (2), and a compression spring (3) installed at the ends of the heel-shaped structure (1) and the foot-shaped structure (4); the talus-shaped structure (2) is connected to one end of the Achilles tendon-shaped structure (5), and the other end of the Achilles tendon-shaped structure (5) is connected to the ball screw slider (7); a ball screw nut (8) is fixed on the ball screw slider (7); the two ends of the ball screw (9) are fixed to the tibia-shaped structure (13) through the screw base (6) and the screw top fixing block (10); a ball screw support rod (11) is installed between the screw base (6) and the screw top fixing block (10); the ball screw slider (7) is guided by the ball screw support rod (11); and a prosthesis socket connecting block (19) is fixed at the top of the tibia-shaped structure (13). The ball screw (9) is driven by a motor (12), which is fixed to the tibial contour structure (13) by a motor mounting bracket (14). The tibial contour structure (13) and the talus contour structure (2) form a rolling joint, which is connected by four fixed springs (16). The heel contouring structure (1) and the foot contouring structure (4) are designed in a personalized manner based on the height of the human foot arch and the curvature characteristics, so as to achieve elastic deformation close to that of the human foot. Lateral limitation is achieved by the protrusion design of the talus mimicry structure (2) and the concave design corresponding to the tibial mimicry structure (13), ensuring that the rolling surface of the rolling joint formed by the tibial mimicry structure (13) and the talus mimicry structure (2) will not slide laterally. The output shaft of the motor (12) is connected to a small pulley (17), which is connected to a large pulley (18) via a synchronous belt (20). The large pulley (18) is connected to the input end of the ball screw (9).

2. The intelligent foot and ankle prosthesis based on human body structure and motion biomimicry according to claim 1, characterized in that: The heel-shaped structure (1) and the foot-shaped structure (4) store and release energy during normal gait walking by compression deformation in conjunction with the compression spring (3). The heel-shaped structure (1) and the foot-shaped structure (4) simulate the storage and release of energy by the tendons around the arch of the foot and the ankle joint.

3. The intelligent foot and ankle prosthesis based on human body structure and motion bionics according to claim 1, characterized in that: The rolling surfaces of the tibia mimicry structure (13) and the talus mimicry structure (2) are obtained by conducting biomimetic research and analysis on the human ankle joint, establishing a three-dimensional model of the human ankle joint surface, extracting key contact points of the joint and performing polynomial fitting to obtain its joint trajectory curve, fixing the spring (16) to ensure that the rolling surfaces are always in contact, and at the same time, the specific motion trajectory of the talus mimicry structure (2) is output by defining the shape of the rolling surface during the design process.

4. The intelligent foot and ankle prosthesis based on human body structure and motion bionics according to claim 1, characterized in that: The motor (12) captures the motor speed and acceleration information through the encoder (15), and then adjusts the motor speed to ensure that the ankle joint rotation amplitude, speed and walking speed are matched. The motor (12) selects the stroke according to the size of the toe stroke and adjusts the forward and reverse rotation of the motor (12) according to the dorsiflexion and plantarflexion state of the ankle joint.

5. The intelligent foot and ankle prosthesis based on human body structure and motion bionics according to claim 1, characterized in that: The tibial prosthetic structure (13) is provided with a prosthetic socket connecting block (19) that connects to the prosthetic socket. The prosthetic socket connecting block (19) can be replaced according to different usage requirements to achieve fine adjustment of the height of the patient's affected limb. The foot prosthetic structure (4) has a U-shaped hole at the end of the connection point, which can be adjusted back and forth to achieve appropriate adjustment of the size of the patient's entire foot.

6. The intelligent foot and ankle prosthesis based on human body structure and motion bionics according to claim 4, characterized in that: The motor (12) adopts the electromyographic signal control mode. The patient's movement intention is analyzed by electromyographic signal, and the working conditions of the activity site where the patient is located are determined. The control mode is switched between different working conditions by electromyographic signal and ranging radar control at the activity site.

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