CN114795605A - Magnetorheological knee joint prosthesis and control method - Google Patents

Abstract

A magnetorheological knee joint prosthesis and a control method belong to the technical field of medical apparatus, and the prosthesis receiving cavity, the magnetorheological knee joint prosthesis, a shank and a foot plate of the invention are sequentially arranged from top to bottom; the magnetorheological knee joint prosthesis consists of a rotor component, a stator component, a motion measurement control component, a single-axis pressure sensor and a leg pipe connecting piece, wherein the stator component, the motion measurement control component, the single-axis pressure sensor and the leg pipe connecting piece are sequentially arranged from top to bottom and fixedly connected; the invention is based on the characteristics of magnetic rheology, the controllable and adjustable damping value range is larger, the response time is fast, the stability is high, the invention can automatically adapt to the gait of standing up/sitting down, constant speed, slow speed and fast speed, and can be automatically adjusted according to the motion environments of flat ground, ascending/descending slope, descending stairs and the like.

Description

Magnetorheological knee joint prosthesis and control method

Technical Field

The invention belongs to the technical field of medical instruments, and particularly relates to a magnetorheological knee joint prosthesis and a control method thereof.

Background

The knee joint artificial limb can help the above-knee amputation patient to rebuild the walking movement function, improve the self-care level of life, normally participate in social and economic activities, and make up the physiological and psychological injuries brought to the patient by amputation. Prosthetic knee joints can be classified into passive, active and semi-active types according to their driving methods. The passive artificial knee joint is regulated and controlled by passive devices such as springs and dampers, and only has a constant torque curve in the walking process. However, the moment of the knee joint is changed in real time according to factors such as step length, pace, terrain and the like in actual walking, so that the passive artificial limb knee joint cannot ensure the gait coordination and comfort of the human body; the active artificial limb knee joint is driven by an external driver such as a motor to input power, can be regulated and controlled by various embedded sensors in an auxiliary mode, and can assist an amputee in performing various daily exercises, however, the power-mass ratio of the external driver is far lower than that of a healthy leg skeletal muscle system, and a large-capacity battery needs to be carried, so that the light weight of an artificial limb structure cannot be guaranteed; according to the characteristic that the knee joint mainly performs negative work in a gait cycle, the intelligent regulation type knee joint prosthesis regulates the damping of the knee joint in real time through data fed back by a sensor, the motion stability and the motion smoothness can be guaranteed without externally connecting driving power, the knee joint prosthesis not only overcomes the defect that a passive prosthesis knee joint is uncontrollable, but also has no driving equipment with high energy consumption in an active knee joint, and the overall weight of the joint is reduced. Therefore, the invention designs the magnetorheological knee prosthesis based on the idea of the intelligent regulation type knee prosthesis, and the damping of the knee joint is regulated by regulating the friction coefficient of the magnetorheological fluid. The joint has compact integral structure and light weight, and a matched control method is developed to highly fit the normal movement gait of the human body.

Disclosure of Invention

The invention aims to help an above-knee amputation patient rebuild the walking movement function, designs a magnetorheological knee joint prosthesis and a control method, the whole structure of the joint is compact, the weight is light, the controllable and adjustable damping value range is larger based on the characteristics of magnetorheological, the response time is fast, the invention can automatically adapt to downstairs, slope walking and the like to maintain self stable movement with large damping besides normal flat walking, and the invention highly fits the normal movement gait of the human body by the developed matching control method.

The magnetorheological knee joint comprises an artificial limb receiving cavity 1, a magnetorheological knee joint artificial limb A, a lower leg 2 and a foot plate 3, wherein the artificial limb receiving cavity 1, the lower leg 2 and the foot plate 3 are commercially available parts, and the artificial limb receiving cavity 1, the magnetorheological knee joint artificial limb A, the lower leg 2 and the foot plate 3 are sequentially arranged from top to bottom and fixedly connected; the magnetorheological knee joint prosthesis A is composed of a rotor assembly B, a stator assembly C, a motion measurement control assembly D, a single-axis pressure sensor 4 and a leg pipe connecting piece 5, wherein the horizontal center lines of the rotor assembly B and the stator assembly C are overlapped; the stator assembly C, the motion measurement control assembly D, the single-shaft pressure sensor 4 and the leg pipe connecting piece 5 are sequentially arranged from top to bottom; the outer ring of a bearing I9 a of the rotor assembly B is in interference connection with a circular truncated cone I21 f of a right stator shell 21 in the stator assembly C; the outer ring of a bearing II 9B of the rotor assembly B is in interference connection with a circular truncated cone II 31d of the left stator shell 31 in the stator assembly C; the battery seat 39 of the movement measurement control assembly D is fixedly connected in a groove I21 e of the right stator shell 21 and a groove II 31C of the left stator shell 31 in the stator assembly C; the upper end face of the single-shaft pressure sensor 4 is fixedly connected with a threaded hole III 21g of the right stator shell 21 and a threaded hole V31 e of the left stator shell 31 in the stator assembly C; the leg pipe connecting piece 5 is fixedly connected to the lower end of the single-shaft pressure sensor 4.

The rotor assembly B consists of a screw 6, a magnetic ring fixing seat 7, a magnetic ring 8, a bearing I9 a, a bearing II 9B, a dynamic sealing ring I10 a, a dynamic sealing ring II 10B, a rotor shell 11, an elastic membrane 12, a pressing sheet 13, a quadrangular frustum 14, rotor blades 15, a buffer block I16 and a sealing plug 17, wherein the screw 6, the magnetic ring fixing seat 7, the magnetic ring 8, the bearing I9 a and the dynamic sealing ring I10 a are arranged on the right side of the rotor shell 11 from right to left, and the dynamic sealing ring I10 a is fixedly connected with the right inner contour of an inner contour pair 11B of the rotor shell 11; the outer ring of the bearing I9 a is in interference connection with the right outer contour of the outer contour pair 11c in the rotor shell 11; the magnetic ring 8 is fixedly connected with the center of the lower part of the magnetic ring fixing seat 7; the upper end of the magnetic ring fixing seat 7 is fixedly connected with a threaded hole I11 a of the rotor shell 11 through a screw 6; the elastic membrane 12, the pressing sheet 13 and the quadrangular frustum 14 are arranged from bottom to top, wherein the elastic membrane 12 and the pressing sheet 13 are fixedly connected with a threaded hole II 11h in the center of the upper surface of the rotor shell 11 through the quadrangular frustum 14; the rotor blade group 15 is fixedly connected with a clamping groove 11e of the inner ring of the rotor shell 11; the bearing II 9 and the dynamic seal ring II 10b are arranged left and right, and the dynamic seal ring II 10b is fixedly connected to the left inner contour of the inner contour pair 11b of the rotor shell 11; the outer ring of the bearing II 9b is in interference connection with the right outer contour of the outer contour pair 11c in the rotor shell 11; the two buffer blocks of the buffer block pair I16 are fixedly connected in the two buffer grooves of the buffer groove pair 11d in the middle of the front of the rotor shell 11; the sealing plug 17 is fixedly connected to the lower hole 11f in the front of the rotor housing 11.

The stator assembly C consists of an oil-free bush 18, a reading head 19, a nut I20 a, a nut II 20b, a right stator shell 21, a buffer block II 22a, a buffer block III 22b, a gasket I23 a, a gasket II 23b, an end cover I24 a, an end cover II 24b, a flat key I25 a, a flat key II 25b, a shaft sleeve 26, an electrified coil 27, stator blades 28, a guide shaft 29, a central shaft 30, a left stator shell 31, a volute spring 32, a dustproof frame 33, a fixed frame 34, a step bush 35 and a step screw 36, wherein the buffer block II 22a is fixedly connected with a buffer groove I21 d of the right stator shell 21; the buffer block III 22b is fixedly connected with a buffer groove II 31b of the left stator shell 31; the oilless bush 18 is fixedly connected to the cylinder 21d of the right stator housing 21; the reading head 19 is fixedly connected with a boss 21a of the right stator shell 21; the upper part of the right stator shell 21, a gasket I23 a, an end cover I24 a, a shaft sleeve 26, an energizing coil 27, stator blades 28, a guide shaft 29, a central shaft 30, an end cover II 24b, a gasket II 23b and the upper part of the left stator shell 31 are coaxially arranged, the guide shaft 29 penetrates through the upper part of the right stator shell 21, the gasket I23 a, the end cover I24 a, the shaft sleeve 26, the end cover II 24b, the gasket II 23b and the left stator shell 31, and the right end of the guide shaft 29 is fixedly connected to a circular groove I21 c of the right stator shell 21 through a nut I20 a; the left end of the guide shaft 29 is fixedly connected with a circular groove II 31a of the left stator shell 31 through a nut II 20 b; the central shaft 30 is fixedly connected between the two end covers 24, the electrified coil 27 is fixedly connected with a main shaft 30a of the central shaft 30, the flat key 25 is fixedly connected with a key groove 30b of the central shaft 30, and the blades of the stator blade group 28 are uniformly arranged and fixedly connected in the shaft sleeve 26; the scroll spring 32, the dust-proof frame 33, the fixing frame 34, the step bush 35 and the step screw 36 are coaxially arranged, and the scroll spring 32 is fixedly connected with the spring groove 30c of the central shaft 30; the step bush 35 is fixedly connected to a threaded hole IV 30d of the central shaft 30 through a step screw 36; the dustproof frame 33 is in rotating fit with the step bush 35; the holder 34 is rotatably fitted with the step bush 35.

The motion measurement control assembly D consists of a microprocessor 37, a storage battery 38, a battery seat 39 and a current control circuit board 40, wherein the storage battery 38 is fixedly connected to the upper end surface of the battery seat 39; the microprocessor 37 is fixedly connected to the upper end of the storage battery 38; the current control circuit board 40 is fixed to the lower end face of the battery holder 39.

The invention relates to a control method of a magnetorheological knee prosthesis, wherein a joint sensing unit is provided with an angle encoder consisting of a magnetic ring 8 and a reading head 19, an inertia measuring unit and a uniaxial pressure sensor 4 which are positioned on a microprocessor 37, the data information of the angle, the position posture, the acceleration, the force and the moment of the knee joint movement is respectively transmitted to the microprocessor 37 through an analog-digital converter A/D converter, the data judges the movement state of the knee joint prosthesis through a movement intention recognition algorithm and a terrain recognition algorithm which are stored by the microprocessor 37, the torque required by the knee joint prosthesis at the next moment is planned through a finite state machine algorithm and is transmitted to a current control circuit board 40 through a PWM signal, the current control circuit board 40 outputs corresponding current to an energizing coil 27 to control the friction coefficient of the magnetorheological fluid, and the volute scroll cooperates with the torque generated by the self deformation of a spring 32, finally, the torque is acted on a knee joint prosthesis actuating mechanism, and the cycle is repeated, so that the torque of the knee joint prosthesis is highly matched with the torque of the joints of a healthy human body. Wherein the joint sensing unit, the microprocessor 37 and the current control circuit board 40 are powered by the battery 38.

The invention has the beneficial effects that: the invention relates to a knee joint artificial limb designed based on a magneto-rheological technology, which has the advantages of large controllable and adjustable damping value range, quick response time and high stability, can automatically adapt to the gaits of standing up/sitting down, constant speed, slow speed and quick speed, and can be automatically debugged according to the motion environments of flat ground, ascending/descending slope, descending stairs and the like; the joint torque of a healthy human body can be highly fitted through an efficient finite-state machine control method; the artificial limb has compact integral structure and light weight, and can improve the comfort of wearing and moving of a patient.

Drawings

FIG. 1 is a perspective view of a magnetorheological knee prosthesis;

FIG. 2 is a right side view of the magnetorheological knee prosthesis;

FIG. 3 is a left side view of a magnetorheological knee prosthesis;

FIG. 4 is a front view of a magnetorheological knee prosthesis;

FIG. 5 is an exploded view of a magnetorheological knee prosthesis;

FIG. 6 is an exploded view of the rotor assembly;

FIG. 7 is a perspective view of the rotor housing;

FIG. 8 is a right side view of the rotor housing;

FIG. 9 is a cross-sectional view of the rotor housing;

FIG. 10 is an exploded view of the stator assembly;

FIG. 11 is an exterior perspective view of the right stator housing;

FIG. 12 is an interior perspective view of the right stator housing;

FIG. 13 is a right side view of the right stator housing;

FIG. 14 is a perspective view of a central shaft;

fig. 15 is an external perspective view of the left stator housing;

fig. 16 is an interior perspective view of the left stator housing;

FIG. 17 is a left side view of the left stator housing;

FIG. 18 is a perspective view of the motion measurement control assembly;

FIG. 19 is an exploded view of the motion measurement control assembly;

FIG. 20 is a cross-sectional view of a magnetorheological knee prosthesis;

FIG. 21 is a schematic view of a magnetorheological knee prosthesis in an inoperative state;

FIG. 22 is a schematic view of the magnetorheological knee prosthesis in an operating state;

FIG. 23 is a simulation diagram of torque of a knee joint when energized;

FIG. 24 is a control block diagram of a magnetorheological knee prosthesis;

FIG. 25 is a block diagram illustrating terrain recognition and determination for a magnetorheological knee prosthesis;

FIG. 26 is a schematic view of a gait cycle phase;

FIG. 27 is a graph showing the relationship between the knee joint angle and the torque in the slow state;

FIG. 28 is a graph showing the relationship between the knee joint angle and the torque at a constant speed;

FIG. 29 is a graph showing the relationship between the knee joint angle and the torque in the rapid state;

FIG. 30 is a line graph of knee joint torque for one cycle from standing to sitting to standing;

FIG. 31 is a line graph of knee joint torque during a cycle of going upstairs;

FIG. 32 is a line graph of knee joint torque during a cycle of uphill descent;

FIG. 33 is a line graph of knee joint torque for one cycle down a slope;

wherein: 1. the magnetic rheological knee joint prosthesis comprises a prosthesis receiving cavity A, a magnetorheological knee joint prosthesis 2, a lower leg 3, a foot plate B, a rotor assembly C, a stator assembly 4, a single-shaft pressure sensor 5, a leg pipe connecting piece 6, a screw 7, a magnetic ring fixing seat 8, a magnetic ring 9, a bearing I9 b, a bearing II 10, a dynamic sealing ring 10a, a dynamic sealing ring I10 b, a dynamic sealing ring II 11, a rotor shell 11a, a threaded hole I11 b, an inner contour pair I11 c, an outer contour pair II 11d, a buffer slot pair 11e, a clamping slot I11 f, a lower hole II 12, an elastic diaphragm 13, a pressing piece 14, a square frustum 15, a rotor blade 16, a buffer block I17, a sealing plug 18, an oil-free bush 19, a reading head 20, a nut I20 b, a nut II, a right stator shell 21a, a boss 21b, a cylinder 21c, a circular slot I21 d, a buffer slot I21 e, a groove I21 f, a circular truncated cone I21 g, a threaded hole I21 g, a III 22a, a buffer block II 22b, a buffer block III 23, a gasket 23a, a gasket I23 b, a gasket II 24, an end cover 24a, an end cover I24 b, an end cover II 25, a flat key 25a, a flat key I25 b, a flat key II 26 shaft sleeve 27, an electrified coil 28, a stator blade 29, a guide shaft 30, a central shaft 30a, a main shaft 30b, a key groove 30c, a spring groove 30d, a threaded hole IV 31, a left stator shell 31a, a circular groove II 31b, a buffer groove II 31c, a groove II 31d, a circular table II 31e, a threaded hole V32, a scroll spring 33, a dustproof frame 34, a fixed frame 35, a step bushing 36, a step screw 37, a microprocessor 38, a storage battery 39, a current control circuit board 41, magnetorheological fluid 42 and magnetorheological fluid.

Detailed Description

The invention is described below with reference to the accompanying drawings.

As shown in fig. 1 to 5, a magnetorheological knee joint of the present invention comprises a prosthetic socket 1, a magnetorheological knee prosthesis a, a lower leg 2 and a foot plate 3, wherein the prosthetic socket 1, the lower leg 2 and the foot plate 3 are commercially available parts; wherein the artificial limb receiving cavity 1, the magnetorheological knee joint artificial limb A, the shank 2 and the foot plate 3 are sequentially arranged from top to bottom and fixedly connected; the magnetorheological knee joint prosthesis A is composed of a rotor assembly B, a stator assembly C, a motion measurement control assembly D, a single-axis pressure sensor 4 and a leg pipe connecting piece 5, wherein the horizontal center lines of the rotor assembly B and the stator assembly C are overlapped; the stator assembly C, the motion measurement control assembly D, the single-shaft pressure sensor 4 and the leg pipe connecting piece 5 are sequentially arranged from top to bottom; the outer ring of a bearing I9 a of the rotor assembly B is in interference connection with a circular truncated cone I21 f of a right stator shell 21 in the stator assembly C; the outer ring of a bearing II 9B of the rotor assembly B is in interference connection with a circular truncated cone II 31d of the left stator shell 31 in the stator assembly C; the battery seat 39 of the movement measurement control assembly D is fixedly connected in a groove I21 e of the right stator shell 21 and a groove II 31C of the left stator shell 31 in the stator assembly C; the upper end face of the single-shaft pressure sensor 4 is fixedly connected with a threaded hole III 21g of the right stator shell 21 and a threaded hole V31 e of the left stator shell 31 in the stator assembly C; the leg pipe connecting piece 5 is fixedly connected to the lower end of the single-shaft pressure sensor 4.

As shown in fig. 6 to 9, the rotor assembly B is composed of a screw 6, a magnetic ring fixing seat 7, a magnetic ring 8, a bearing i 9a, a bearing ii 9B, a dynamic seal ring i 10a, a dynamic seal ring ii 10B, a rotor housing 11, an elastic membrane 12, a pressing sheet 13, a quadrangular frustum 14, rotor blades 15, a buffer block i 16 and a seal plug 17, wherein the screw 6, the magnetic ring fixing seat 7, the magnetic ring 8, the bearing i 9a and the dynamic seal ring i 10a are arranged on the right side of the rotor housing 11 from right to left, and the dynamic seal ring i 10a is fixedly connected to the right inner contour of the inner contour pair 11B of the rotor housing 11; the outer ring of the bearing I9 a is in interference connection with the right outer contour of the outer contour pair 11c in the rotor shell 11; the magnetic ring 8 is fixedly connected with the center of the lower part of the magnetic ring fixing seat 7; the upper end of the magnetic ring fixing seat 7 is fixedly connected with a threaded hole I11 a of the rotor shell 11 through a screw 6; the elastic membrane 12, the pressing sheet 13 and the quadrangular frustum 14 are arranged from bottom to top, wherein the elastic membrane 12 and the pressing sheet 13 are fixedly connected with a threaded hole II 11h in the center of the upper surface of the rotor shell 11 through the quadrangular frustum 14; the rotor blade group 15 is fixedly connected with a clamping groove 11e of the inner ring of the rotor shell 11; the bearing II 9 and the dynamic seal ring II 10b are arranged left and right, and the dynamic seal ring II 10b is fixedly connected to the left inner contour of the inner contour pair 11b of the rotor shell 11; the outer ring of the bearing II 9b is in interference connection with the right outer contour of the outer contour pair 11c in the rotor shell 11; the two buffer blocks of the buffer block pair I16 are fixedly connected in the two buffer grooves of the buffer groove pair 11d in the middle of the front of the rotor shell 11; the sealing plug 17 is fixedly connected to the lower hole 11f in the front of the rotor housing 11. Magnetorheological fluid which is prepared in proportion is injected into the magnetorheological knee joint prosthesis from the lower hole 11f in front of the rotor shell 11 and is sealed by the sealing plug 17. Since the volume of the magnetorheological fluid is heated to expand when the temperature inside the prosthesis is increased during operation or the temperature in summer is high, the elastic membrane 12 is designed to adjust the volume change caused by the temperature.

As shown in fig. 10 to 17, the stator assembly C is composed of an oil-free bushing 18, a reading head 19, a nut i 20a, a nut ii 20b, a right stator housing 21, a buffer block ii 22a, a buffer block iii 22b, a gasket i 23a, a gasket ii 23b, an end cover i 24a, an end cover ii 24b, a flat key i 25a, a flat key ii 25b, a shaft sleeve 26, an energizing coil 27, a stator blade 28, a guide shaft 29, a central shaft 30, a left stator housing 31, a volute spring 32, a dust-proof frame 33, a fixed frame 34, a step bushing 35 and a step screw 36, wherein the buffer block ii 22a is fixedly connected to a buffer groove i 21d of the right stator housing 21; the buffer block III 22b is fixedly connected with a buffer groove II 31b of the left stator shell 31; the oilless bush 18 is fixedly connected to the cylinder 21d of the right stator housing 21; the reading head 19 is fixedly connected with a boss 21a of the right stator shell 21; the upper part of the right stator shell 21, a gasket I23 a, an end cover I24 a, a shaft sleeve 26, an energizing coil 27, stator blades 28, a guide shaft 29, a central shaft 30, an end cover II 24b, a gasket II 23b and the upper part of the left stator shell 31 are coaxially arranged, the guide shaft 29 penetrates through the upper part of the right stator shell 21, the gasket I23 a, the end cover I24 a, the shaft sleeve 26, the end cover II 24b, the gasket II 23b and the left stator shell 31, and the right end of the guide shaft 29 is fixedly connected to a circular groove I21 c of the right stator shell 21 through a nut I20 a; the left end of the guide shaft 29 is fixedly connected with a circular groove II 31a of the left stator shell 31 through a nut II 20 b; the central shaft 30 is fixedly connected between the two end covers 24, the electrified coil 27 is fixedly connected with a main shaft 30a of the central shaft 30, the flat key 25 is fixedly connected with a key groove 30b of the central shaft 30, and the blades of the stator blade group 28 are uniformly arranged and fixedly connected in the shaft sleeve 26; the scroll spring 32, the dust-proof frame 33, the fixing frame 34, the step bush 35 and the step screw 36 are coaxially arranged, and the scroll spring 32 is fixedly connected with the spring groove 30c of the central shaft 30; the step bush 35 is fixedly connected to a threaded hole IV 30d of the central shaft 30 through a step screw 36; the dustproof frame 33 is in rotating fit with the step bush 35; the holder 34 is rotatably fitted with the step bush 35.

As shown in fig. 18 and 19, the motion measurement and control assembly D comprises a microprocessor 37, a battery 38, a battery holder 39 and a current control circuit board 40, wherein the battery 38 is fixedly connected to the upper end surface of the battery holder 39; the microprocessor 37 is fixedly connected to the upper end of the storage battery 38; the current control circuit board 40 is fixed to the lower end face of the battery holder 39.

Fig. 20 is a cross-sectional view of a magnetorheological knee prosthesis illustrating its fully assembled effect.

As shown in fig. 21 and 22, schematic diagrams of the non-working state of the magnetorheological knee prosthesis and the working state of the magnetorheological knee prosthesis are shown. The magnetorheological fluid prepared in proportion consists of magnetorheological particles 41 and magnetorheological fluid 42, and when no magnetic field acts, the magnetorheological particles 41 are randomly arranged in the magnetorheological fluid 42 and do not prevent the rotor blades 15 and the stator blades 28 from rotating; when the magnetic field acts, the magnetorheological particles 41 form a chain structure in the magnetorheological fluid 42 to generate resistance to prevent the rotor blades 15 and the stator blades 28 from rotating, and the stronger the magnetic field, the larger the resistance is; it can be known from the biot-savart law that the magnetic field strength is proportional to the current of the energized coil 27 when the coil structure is determined.

As shown in fig. 23, a simulation plot of the torque of the knee joint simulated by energization is shown, with simulated input currents of 1.5A, 2A, 2.5A and 10A, respectively. According to simulation, the current can be obtained by inputting the control current, so that the magnetorheological fluid can generate a large friction coefficient, and the knee joint torque is obtained in a one-to-one correspondence relationship. Therefore, the intensity of the electrified current of the coil can be controlled, the intensity of the magnetic field can be controlled, the friction coefficient of the magnetorheological fluid can be controlled, and the aim of controlling the torque of the knee joint can be finally achieved.

As shown in fig. 24, there is shown a control block diagram of a magnetorheological knee prosthesis, wherein the joint sensing unit comprises an angle encoder consisting of a magnetic ring 8 and a reading head 19, an inertia measuring unit and a uniaxial pressure sensor 4 which are arranged on a microprocessor 37, data information of angle, position posture, acceleration, force and moment of knee joint movement is respectively transmitted to the microprocessor 37 through an analog-digital converter a/D converter, the data judges the movement state of the knee joint prosthesis through a movement intention recognition algorithm and a terrain recognition algorithm stored in the microprocessor 37, a torque required by the knee joint prosthesis at the next moment is planned through a finite state machine algorithm, a PWM signal is transmitted to a current control circuit board 40, the current control circuit board 40 outputs a corresponding current to an energizing coil 27, controls the friction coefficient of the magnetorheological fluid and cooperates with the torque generated by the self deformation of a volute spring 32, finally, the torque is acted on a knee joint prosthesis actuating mechanism, and the cycle is repeated, so that the torque of the knee joint prosthesis is highly matched with the torque of the joint of a healthy human body, wherein the joint sensing unit, the microprocessor 37 and the current control circuit board 40 are powered by the storage battery 38.

As shown in fig. 25, a schematic diagram of terrain determination and transition is shown, and the present invention implements determination of terrain by using three-level classification, in which standing and walking are identified first. If the patient is in a standing state, the next-stage motion control is not needed; if the patient is walking, the second stage classification begins to identify the gait phase: in the standing phase or in the swing phase. The task of the third level of classification is to identify 5 stable modes of level ground walking LG, stair ascent SA, stair descent SD, ramp ascent RA, ramp descent RD and transition modes between two of them. In the first-stage classification, a quadratic discriminant analysis QDA is used as a recognition model, and a classifier is trained by using stable modal data obtained by early-stage experimental measurement; in the second-level classification, a threshold value method is adopted to determine the swing and the standing of two gait stages; in the three-level classification, two three-level classifiers are trained based on a gait phase dependence method, wherein one three-level classifier identifies 5 stable modes, and the other three-level classifier identifies a transition mode.

As shown in fig. 26, the schematic diagram of the complete gait cycle of walking on flat ground is divided into two phases of a stance phase and a swing phase, which are subdivided into a stance flexion phase, a stance extension phase, a pre-swing phase, a swing flexion phase and a swing extension phase. And (3) using a quadratic discriminant analysis QDA and a support vector machine SVM as recognition models, and distinguishing transitional actions on the magnetorheological knee prosthesis by using data from an inertia measurement unit and a single-axis pressure sensor 1 to achieve the aim of recognizing the movement intention.

Fig. 27 to 29 are graphs showing torque required for the knee joint in the slow, constant and fast walking motion states, respectively. The curve is the torque required by the knee joint in the healthy human motion state, and the motion period from the heel landing to the toe-off to the heel landing in the next stage is one motion period. The slope of a tangent line at a certain point on the curve represents the rigidity characteristic of the knee joint, so that the broken line shown in the graph is used for highly fitting the torque of the knee joint of a healthy human body, the slope of the broken line represents the rigidity characteristic of the knee joint prosthesis, and the broken line with a limited section can be used for replacing the torque of the knee joint. The torque of the knee joint prosthesis is provided under the combined action of the magnetorheological fluid and the volute spiral spring, namely the rigidity characteristic of the knee joint prosthesis is determined by the friction coefficient of the magnetorheological fluid and the elastic modulus of the volute spiral spring. The elasticity modulus of the volute spiral spring on the knee joint prosthesis is a fixed value, so that the invention only needs to control the size of the electrified current of the coil, control the intensity of the magnetic field, control the friction coefficient of the magnetorheological fluid, and form a one-to-one correspondence relationship between the input current value and the slope of the dotted line. After the intention recognition algorithm and the terrain recognition algorithm are operated, namely the motion state of the current knee joint prosthesis is determined, the finite-state machine algorithm in the microprocessor judges which dotted line is used for fitting the knee joint torque curve in the current state, and then a PWM signal is output to enable the current control board to output a corresponding current value.

As shown in fig. 30 to 33, the torque of the knee joint is shown in a cycle of standing to sitting to standing, going downstairs and going up/down-grades, wherein the curve is the torque required by the knee joint in the motion state of a healthy human body, the dotted line is the fitting line for controlling the torque of the knee joint prosthesis, and the control principle is the same as walking.

Claims (2)

1. The utility model provides a magnetorheological type knee joint artificial limb, comprises artificial limb accepting cavity (1), magnetorheological knee joint artificial limb (A), shank (2) and sole (3), and wherein artificial limb accepting cavity (1), shank (2) and sole (3) are the part of selling, its characterized in that: the artificial limb receiving cavity (1), the magnetorheological knee joint artificial limb (A), the crus (2) and the foot plate (3) are sequentially arranged from top to bottom and fixedly connected; the magnetorheological knee joint prosthesis (A) consists of a rotor component (B), a stator component (C), a motion measurement control component (D), a single-axis pressure sensor (4) and a leg pipe connecting piece (5), wherein the horizontal center lines of the rotor component (B) and the stator component (C) are superposed; the stator component (C), the motion measurement control component (D), the single-shaft pressure sensor (4) and the leg pipe connecting piece (5) are sequentially arranged from top to bottom; the rotor assembly (B) consists of a screw (6), a magnetic ring fixing seat (7), a magnetic ring (8), a bearing I (9a), a bearing II (9B), a dynamic sealing ring I (10a), a dynamic sealing ring II (10B), a rotor shell (11), an elastic membrane (12), a pressing sheet (13), a quadrangular frustum (14), rotor blades (15), a buffer block I (16) and a sealing plug (17), wherein the screw (6), the magnetic ring fixing seat (7), the magnetic ring (8), the bearing I (9a) and the dynamic sealing ring I (10a) are arranged on the right side of the rotor shell (11) from right to left, and the dynamic sealing ring I (10a) is fixedly connected to the right inner contour of the inner contour pair (11B) of the rotor shell (11); the outer ring of the bearing I (9a) is in interference connection with the right outer contour of the outer contour pair (11c) in the rotor shell (11); the magnetic ring (8) is fixedly connected with the center of the lower part of the magnetic ring fixing seat (7); the upper end of the magnetic ring fixing seat (7) is fixedly connected with a threaded hole I (11a) of the rotor shell (11) through a screw (6); the elastic membrane (12), the pressing sheet (13) and the quadrangular frustum (14) are arranged from bottom to top, wherein the elastic membrane (12) and the pressing sheet (13) are fixedly connected with a threaded hole II (11h) in the center of the upper surface of the rotor shell (11) through the quadrangular frustum (14); the rotor blade group (15) is fixedly connected with a clamping groove (11e) of the inner ring of the rotor shell (11); the bearing II (9) and the dynamic seal ring II (10b) are arranged left and right, and the dynamic seal ring II (10b) is fixedly connected to the left inner contour of the inner contour pair (11b) of the rotor shell (11); the outer ring of the bearing II (9b) is in interference connection with the right outer contour of the outer contour pair (11c) in the rotor shell (11); two buffer blocks of the buffer block pair I (16) are fixedly connected in two buffer grooves of a buffer groove pair (11d) in the middle of the front of the rotor shell (11); the sealing plug (17) is fixedly connected with a lower hole (11f) in front of the rotor shell (11); the stator assembly (C) consists of an oil-free bushing (18), a reading head (19), a nut I (20a), a nut II (20b), a right stator shell (21), a buffer block II (22a), a buffer block III (22b), a gasket I (23a), a gasket II (23b), an end cover I (24a), an end cover II (24b), a flat key I (25a), a flat key II (25b), a shaft sleeve (26), an electrified coil (27), stator blades (28), a guide shaft (29), a central shaft (30), a left stator shell (31), a volute spring (32), a dustproof frame (33), a fixed frame (34), a step bushing (35) and a step screw (36), wherein the buffer block II (22a) is fixedly connected to a buffer groove I (21d) of the right stator shell (21); the buffer block III (22b) is fixedly connected with a buffer groove II (31b) of the left stator shell (31); the oilless bush (18) is fixedly connected to a cylinder (21d) of the right stator housing (21); the reading head (19) is fixedly connected with a boss (21a) of the right stator shell (21); the stator comprises a right stator shell (21), a gasket I (23a), an end cover I (24a), a shaft sleeve (26), an energizing coil (27), stator blades (28), a guide shaft (29), a central shaft (30), an end cover II (24b), a gasket II (23b) and a left stator shell (31), wherein the upper parts of the right stator shell (21), the gasket I (23a), the end cover I (24a), the shaft sleeve (26), the end cover II (24b), the gasket II (23b) and the left stator shell (31) are coaxially arranged, the guide shaft (29) penetrates through the upper part of the right stator shell (21), and the right end of the guide shaft (29) is fixedly connected to a circular groove I (21c) of the right stator shell (21) through a nut I (20 a); the left end of the guide shaft (29) is fixedly connected with a circular groove II (31a) of the left stator shell (31) through a nut II (20 b); the central shaft (30) is fixedly connected between the two end covers (24), the electrified coil (27) is fixedly connected with a main shaft (30a) of the central shaft (30), the flat key (25) is fixedly connected with a key groove (30b) of the central shaft (30), and blades of the stator blade group (28) are uniformly arranged and fixedly connected in the shaft sleeve (26); the scroll spring (32), the dustproof frame (33), the fixed frame (34), the step bushing (35) and the step screw (36) are coaxially arranged, and the scroll spring (32) is fixedly connected with a spring groove (30c) of the central shaft (30); the step bush (35) is fixedly connected with a threaded hole IV (30d) of the central shaft (30) through a step screw (36); the dustproof frame (33) is in rotating fit with the step bush (35); the fixed frame (34) is rotationally matched with the step bush (35); the motion measurement control assembly (D) consists of a microprocessor (37), a storage battery (38), a battery holder (39) and a current control circuit board (40), wherein the storage battery (38) is fixedly connected to the upper end face of the battery holder (39); the microprocessor (37) is fixedly connected to the upper end of the storage battery (38); the current control circuit board (40) is fixedly connected with the lower end surface of the battery seat (39); the outer ring of a bearing I (9a) of the rotor assembly (B) is in interference connection with a circular truncated cone I (21f) of a stator shell (21) on the right side in the stator assembly (C); the outer ring of a bearing II (9B) of the rotor assembly (B) is in interference connection with a circular truncated cone II (31d) of a left stator shell (31) in the stator assembly (C); a battery seat (39) of the movement measurement control assembly (D) is fixedly connected in a groove I (21e) of a right stator shell (21) and a groove II (31C) of a left stator shell (31) in the stator assembly (C); the upper end face of the single-shaft pressure sensor (4) is fixedly connected with a threaded hole III (21g) of a right stator shell (21) and a threaded hole V (31e) of a left stator shell (31) in the stator assembly (C); the leg pipe connecting piece (5) is fixedly connected to the lower end of the single-shaft pressure sensor (4).

2. A method of controlling a magnetorheological knee prosthesis in accordance with claim 1, comprising the steps of: the joint sensing unit is provided with an angle encoder consisting of a magnetic ring (8) and a reading head (19), an inertia measuring unit and a single-shaft pressure sensor (4) which are positioned on a microprocessor (37), the data information of the angle, the position posture, the acceleration, the force and the moment of the knee joint movement is respectively transmitted to the microprocessor (37) through an analog-digital converter A/D converter, the data judges the movement state of the knee joint artificial limb through a movement intention recognition algorithm and a terrain recognition algorithm which are stored in the microprocessor (37), the torque required by the knee joint artificial limb at the next moment is planned through a finite state machine algorithm and transmitted to a current control circuit board (40) through a PWM signal, the current control circuit board (40) outputs corresponding current to an energizing coil (27) to control the friction coefficient of the magnetic current, and the torque generated by the self deformation of a volute spiral spring (32) is matched, finally, the torque is acted on a knee joint prosthesis actuating mechanism, the cycle is repeated, the torque of the knee joint prosthesis is highly matched with the torque of the joint of a healthy human body, and the joint sensing unit, the microprocessor (37) and the current control circuit board (40) are powered by the storage battery (38).

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