A rigid-flexible coupling ankle joint rehabilitation robot

Abstract

The application discloses a rigid-flexible coupling ankle joint rehabilitation robot, which comprises a fixed platform, a movable platform, a first supporting chain, a second supporting chain and a third supporting chain; the three supporting chains are connected with the fixed platform and the movable platform, the first supporting chain and the second supporting chain are the same in structure and symmetrically distributed on the two sides of the third supporting chain; each supporting chain comprises a rigid-flexible coupling module, the rigid-flexible coupling module comprises four connecting rods and a torsional spring; the four connecting rods are rotationally connected in sequence to form a parallelogram, and a torsional spring is arranged at the connecting position of adjacent two connecting rods; the driving motors of the three supporting chains control the posture of the movable platform, realize the dorsiflexion / planter flexion, the inversion / eversion and the internal / external rotation of the ankle joint, the rigid-flexible coupling modules of the three supporting chains adjust the position of a movable ball center through the torsional spring, the movable ball center moves on a spherical surface with the length of a talus as a radius, the position of a subtalar joint of a human body is fitted, the motion coupling between a tibiotalar joint and the subtalar joint is realized, the robot can conform to different rehabilitation trajectories of different patients, the ankle joint rehabilitation efficiency is improved, and secondary injury is reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of ankle rehabilitation machines, and particularly relates to a rigid-flexible coupling ankle rehabilitation robot. BACKGROUND

[0002] Ankle joint is an important joint of human body, and as the joint with the largest weight bearing, ankle joint is prone to injury, such as when walking into a pit to make ankle joint suddenly invert and adduct, which can damage the lateral collateral ligament, and even cause ankle fracture in severe cases.

[0003] With the continuous development of robot technology, ankle rehabilitation robots are emerging in endlessly, in order to achieve the purpose of rehabilitation training, the configuration and parameter design of ankle rehabilitation robots need to refer to the real bone structure, common ankle fitting models include RR model, S model and SS model, etc., the SS model combines the characteristics and advantages of RR model and S model, and equivalently regards the tibiotalar joint and subtalar joint as S-shaped joints with stronger motion adaptability, so it has higher matching degree and precision.

[0004] Although the bone structures of different patients are basically similar, and the motion modes are also roughly the same, the tissue ligament structures of different patients are quite different, resulting in different motion coupling relationships of the tibiotalar joint and the subtalar joint, so the rehabilitation trajectories of different patients are also different. In order to achieve good rehabilitation training effect and avoid secondary injury, it is required that the motion of the ankle rehabilitation robot should adapt to the rehabilitation trajectory of different patients, but the existing pure rigid ankle rehabilitation robot cannot meet this requirement.

[0005] Therefore, the present application provides a rigid-flexible coupling ankle rehabilitation robot, which can not only realize the dorsiflexion / toe flexion, inversion / eversion and internal / external rotation of the ankle joint, but also can fit the coupling motion between the supratalar joint and the subtalar joint, so that the rehabilitation robot can adapt to the rehabilitation trajectory of different patients. SUMMARY

[0006] In view of the deficiencies of the prior art, the technical problem to be solved by the present application is to provide a rigid-flexible coupling ankle rehabilitation robot.

[0007] The technical problem of the present application is solved by adopting the following technical solution:

[0008] A rigid-flexible coupling ankle rehabilitation robot, comprising a fixed platform, a moving platform, a first branch chain, a second branch chain and a third branch chain, the three branch chains are connected with the fixed platform and the moving platform, the first branch chain and the second branch chain are the same in structure and symmetrically distributed on both sides of the third branch chain, characterized in that,

[0009] The first branch chain comprises a first branch chain driving motor, a first branch chain first connecting rod, a first branch chain rigid-flexible coupling module and a first branch chain second connecting rod; the first branch chain driving motor is connected with the fixed platform; one end of the first branch chain first connecting rod is connected with an output shaft of the first branch chain driving motor; the other end of the first branch chain first connecting rod is rotatably connected with the first branch chain rigid-flexible coupling module; the first branch chain rigid-flexible coupling module is rotatably connected with one end of the first branch chain second connecting rod; the other end of the first branch chain second connecting rod is rotatably connected with the middle rear part of the movable platform.

[0010] The third branch chain comprises a third branch chain driving motor, a third branch chain first connecting rod, a third branch chain rigid-flexible coupling module, a third branch chain second connecting rod and a third branch chain third connecting rod; the third branch chain driving motor is located at the lower part of the fixed platform; an output shaft of the third branch chain driving motor is connected with one end of the third branch chain first connecting rod; the other end of the third branch chain first connecting rod is rotatably connected with the third branch chain rigid-flexible coupling module; the third branch chain rigid-flexible coupling module is rotatably connected with one end of the third branch chain second connecting rod; the other end of the third branch chain second connecting rod is rotatably connected with the upper ends of the two sides of the third branch chain third connecting rod; the lower end of the third branch chain third connecting rod is fixedly connected with the middle rear part of the movable platform.

[0011] The first branch chain rigid-flexible coupling module and the third branch chain rigid-flexible coupling module have the same structure and each comprises four connecting rods and a torsional spring; the four connecting rods are rotatably connected in sequence to form a parallelogram; one torsional spring is arranged at the connection between adjacent two connecting rods.

[0012] The rehabilitation robot has a fixed ball center and a movable ball center; the driving motors of the three branch chains control the posture of the movable platform to realize the dorsiflexion / toe flexion, inversion / eversion and internal / external rotation of the ankle joint; the rigid-flexible coupling modules of the three branch chains adjust the position of the movable ball center through the torsional springs to make the movable ball center move on a spherical surface with the length of the talus as the radius to fit the position of the subtalar joint of the human body.

[0013] Further, the mapping relationship between the talus posture parameters (α T / β T ) of the rehabilitation robot and the foot posture parameters (α / β / γ) is shown in formula (19); the structure parameters of the rehabilitation robot are obtained according to the mapping relationship. The structure is optimized;

[0014]

[0015]

[0016]

[0017]

[0018] In the formula, g α (·), g β(·) is a mapping function, α T and β T are angles of rotation of the talus around the x, y axes of the fixed coordinate system, α, β and γ are angles of rotation of the foot around the x, y and z axes of the fixed coordinate system, (b 11 , b 12 , b 13 ) T is a unit vector b1 of the axis O1B U1 in the fixed coordinate system, (b 21 , b 22 , b 23 ) T is a unit vector b2 of the axis O1B U2 in the fixed coordinate system, is an angle between the unit vector a1 of the axis O1A1 in the fixed coordinate system and the x axis of the fixed coordinate system, is an angle between the projection of the unit vector a1 on the yoz plane of the fixed coordinate system and the z axis of the fixed coordinate system, is an angle between the unit vector c1 of the axis O2C1 in the fixed coordinate system and the x axis of the fixed coordinate system, is an angle between the projection of the unit vector c1 on the yoz plane of the fixed coordinate system and the x axis of the fixed coordinate system, and are angles between the unit vector b i and the axes O1A i and O2C i respectively, is an angle between the double center line O1O2 and the unit vector b1 or b2, O1 is the fixed center of the rehabilitation robot, O2 is the moving center of the rehabilitation robot, b i is a unit vector b1 of the axis O1B Ui in the fixed coordinate system, B Ui is the rotation center of the i-th first link and the first rigid-flexible coupling module of the first branch chain, A i is the rotation center of the i-th driving motor of the branch chain and the first link, C i is the rotation center of the i-th second link of the branch chain and the moving platform, is a cosine value of the angle ; the origin of the fixed coordinate system is located at the fixed center of the rehabilitation robot, the z axis is perpendicular to the moving platform downward, the y axis coincides with the rotation axis of the first link of the third branch chain and the rigid-flexible coupling module of the third branch chain, and the x axis obeys the right-hand rule; the origin of the moving coordinate system is located at the moving center of the rehabilitation robot, the z axis is perpendicular to the moving platform downward, the x axis coincides with the rotation axis of the right side of the upper end of the third link of the third branch chain and the right side of the other end of the second link of the third branch chain, and the y axis obeys the right-hand rule.

[0019] Further, the unit vector b i satisfies the following equation:

[0020]

[0021] wherein: (a i1 , a i2 , a i3 ) is the coordinate of unit vector b i in the fixed coordinate system, (b i1 , b i2 , b i3 ) T is the coordinate of unit vector b i , (c i1 , c i2 , c i3 ) is the coordinate of unit vector b i in the fixed coordinate system, is the cosine value of the included angle , and is the cosine value of the included angle .

[0022] Further, the rotation axes of the two ends of the first connecting rod of the first branch chain, the rotation axes of the two ends of the first connecting rod of the second branch chain, and the rotation axes of the first connecting rod of the third branch chain and the rigid-flexible coupling module of the third branch chain intersect at the fixed center of the rehabilitation robot; the rotation axes of the two ends of the second connecting rod of the first branch chain, the rotation axes of the two ends of the second connecting rod of the second branch chain, the rotation axes of the two ends of the second connecting rod of the third branch chain and the third connecting rod of the third branch chain, and the axis of the connecting hole of the third connecting rod of the third branch chain and the moving platform intersect at the moving center of the rehabilitation robot.

[0023] Compared with the prior art, the rehabilitation robot has the following beneficial effects:

[0024] 1. According to different motion coupling relationships between the tibiotalar joint and the subtalar joint of different patients, a rigid-flexible coupling module is added in each branch chain on the basis of the SS model, so that not only the dorsiflexion / planter flexion, inversion / eversion and internal / external rotation of the ankle joint can be realized, but also the position of the moving center can be adjusted through the torsional spring of the rigid-flexible coupling module during the motion process, so that the moving center moves on a spherical surface with the length of the talus as the radius, the position of the subtalar joint is fitted, the motion coupling between the tibiotalar joint and the subtalar joint is realized, different positions of the foot of the patient are adapted to, different rehabilitation trajectories of different patients are adapted to, the rehabilitation efficiency of the ankle joint is improved, and the possibility of secondary injury is reduced.

[0025] 2. According to the mapping relationship between the talus posture parameters and the foot posture parameters, the structural parameters of the rehabilitation robot can be obtained, and the optimal design of the rehabilitation robot can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is the overall structural diagram of the present application;

[0027] Figure 2It is the structural diagram of the fixed platform of the application;

[0028] Figure 3 It is the structural diagram of the application in one view;

[0029] Figure 4 It is the structural diagram of the application in another view;

[0030] Figure 5 It is the structural diagram of the first branch chain rigid-flexible coupling module of the application;

[0031] Figure 6 It is the sectional view of the first branch chain rigid-flexible coupling module of the application;

[0032] In the figure: 1, fixed platform; 2, moving platform; 3, first branch chain; 4, second branch chain; 5, third branch chain;

[0033] 101, upper connecting plate; 102, fixed platform column; 103, lower connecting plate; 104, base; 301, first branch chain driving motor; 302, first branch chain first connecting rod; 303, first branch chain rigid-flexible coupling module; 304, first branch chain second connecting rod; 501, third branch chain driving motor; 502, third branch chain first connecting rod; 503, third branch chain rigid-flexible coupling module; 504, third branch chain second connecting rod; 505, third branch chain third connecting rod;

[0034] 303-1, rigid-flexible coupling module first connecting rod; 303-2, rigid-flexible coupling module second connecting rod; 303-3, rigid-flexible coupling module third connecting rod; 303-4, rigid-flexible coupling module fourth connecting rod; 303-5, rigid-flexible coupling module torsional spring. DETAILED DESCRIPTION

[0035] The specific embodiments are given below in combination with the drawings. The specific embodiments are only used to specifically introduce the technical solutions of the application, and do not limit the protection scope of the application.

[0036] The application is a rigid-flexible coupling ankle joint rehabilitation robot, which comprises a fixed platform 1, a moving platform 2, a first branch chain 3, a second branch chain 4 and a third branch chain 5. The three branch chains are connected with the fixed platform 1 and the moving platform 2, and the first branch chain 3 and the second branch chain 4 are symmetrically distributed on both sides of the third branch chain 5.

[0037] The fixed platform 1 comprises an upper connecting plate 101, a fixed platform column 102, a lower connecting plate 103 and a base 104. The base 104 is a frame structure welded by aluminum profiles. The lower connecting plate 103 is located on the base 104, and the upper connecting plate 101 is connected with the lower connecting plate 103 through a plurality of moving platform columns 102. A U-shaped notch accommodating a human calf is formed on the upper connecting plate 101, and the moving platform 2 is located in the space between the upper connecting plate 101 and the lower connecting plate 103.

[0038] The first branch chain 3 and the second branch chain 4 are of the same structure, and the first branch chain 3 is taken as an example for illustration. The first branch chain 3 comprises a first branch chain driving motor 301, a first branch chain first connecting rod 302, a first branch chain rigid-flexible coupling module 303 and a first branch chain second connecting rod 304. The first branch chain driving motor 301 is fixedly connected with the upper connecting plate 101 of the fixed platform 1. The first branch chain driving motor 301 is connected with one end of the first branch chain first connecting rod 302 through a speed reducer. The other end of the first branch chain first connecting rod 302 is rotatably connected with the first branch chain rigid-flexible coupling module 303. The first branch chain rigid-flexible coupling module 303 is rotatably connected with one end of the first branch chain second connecting rod 304. The other end of the first branch chain second connecting rod 304 is rotatably connected with the middle rear part of the movable platform 2.

[0039] The third branch chain 5 comprises a third branch chain driving motor 501, a third branch chain first connecting rod 502, a third branch chain rigid-flexible coupling module 503, a third branch chain second connecting rod 504 and a third branch chain third connecting rod 505. The third branch chain driving motor 501 is fixedly connected with the bottom of the lower connecting plate 103 of the fixed platform 1. The output shaft of the third branch chain driving motor 501 penetrates through the lower connecting plate 103 and is connected with one end of the third branch chain first connecting rod 502 through a speed reducer. The other end of the third branch chain first connecting rod 502 is rotatably connected with the third branch chain rigid-flexible coupling module 503. The third branch chain rigid-flexible coupling module 503 is rotatably connected with one end of the third branch chain second connecting rod 504. The other end of the third branch chain second connecting rod 504 is rotatably connected with the upper ends of the two sides of the third branch chain third connecting rod 505. The lower end of the third branch chain third connecting rod 505 is fixedly connected with the middle rear part of the movable platform 2.

[0040] The rotation axes of the two ends of the first branch chain first connecting rod 302, the rotation axes of the two ends of the second branch chain first connecting rod, the rotation axes of the third branch chain first connecting rod 502 and the third branch chain rigid-flexible coupling module 503 intersect at a point, which is the fixed center of the rehabilitation robot O1. The rotation axes of the two ends of the first branch chain second connecting rod 304, the rotation axes of the two ends of the second branch chain second connecting rod, the rotation axes of the two ends of the third branch chain second connecting rod 504 and the third branch chain third connecting rod 505 and the axis of the connecting hole of the third branch chain third connecting rod 505 and the movable platform 2 intersect at a point, which is the movable center of the rehabilitation robot O2.

[0041] The three branched rigid-flexible coupling modules have the same structure, wherein the first branched rigid-flexible coupling module 303 comprises a rigid-flexible coupling module first connecting rod 303-1, a rigid-flexible coupling module second connecting rod 303-2, a rigid-flexible coupling module third connecting rod 303-3, a rigid-flexible coupling module fourth connecting rod 303-4 and a rigid-flexible coupling module torsion spring 303-5; wherein the two ends of the rigid-flexible coupling module second connecting rod 303-2 are rotatably connected with the rigid-flexible coupling module first connecting rod 303-1 and the rigid-flexible coupling module fourth connecting rod 303-4 through connecting shafts, and the two ends of the rigid-flexible coupling module third connecting rod 303-3 are rotatably connected with the rigid-flexible coupling module first connecting rod 303-1 and the rigid-flexible coupling module fourth connecting rod 303-4 through connecting shafts, and the connecting points of the rigid-flexible coupling module first connecting rod 303-1, the rigid-flexible coupling module second connecting rod 303-2, the rigid-flexible coupling module third connecting rod 303-3 and the rigid-flexible coupling module fourth connecting rod 303-4 form a parallelogram, and a rigid-flexible coupling module torsion spring 303-5 is arranged on each connecting shaft to realize the reset of the parallelogram; one end of the rigid-flexible coupling module first connecting rod 303-1 is rotatably connected with the other end of the first branched first connecting rod 302, and one end of the rigid-flexible coupling module fourth connecting rod 303-4 is rotatably connected with one end of the first branched second connecting rod 304.

[0042] During use, the patient's foot is bound to the moving platform 2, and the drive motors of the three branched chains are controlled by the controller to make the moving platform 2 move around the moving ball center, so that the patient's foot is driven to move, thereby realizing the rehabilitation training of the ankle joint. The robot has three rotational degrees of freedom and two movement degrees of freedom. The three rotational degrees of freedom are reflected in that the three drive motors can realize the complete control of the posture of the moving platform 2, thereby realizing the dorsiflexion / toe flexion, inversion / eversion and internal / external rotation of the ankle joint. The two movement degrees of freedom are reflected in that the rigid-flexible coupling modules of the three branched chains can adjust the position of the moving ball center through the torsion springs, so that the moving ball center moves on the spherical surface with the length of the talus as the radius, so as to fit the position of the subtalar joint, thereby adapting to different positions of the patient's foot. Therefore, the rehabilitation robot can control the posture of the moving platform to adapt to the rehabilitation trajectory of different patients.

[0043] In addition to the rigid ankle bone structure, the ankle joint also includes a large number of complex tissue ligaments. Under the action of the tissue ligaments, the tibiotalar joint and the subtalar joint are no longer independent of each other, but are coupled in movement. This makes the ankle joint only have three degrees of freedom in macroscopically, i.e. dorsiflexion / toe flexion in the sagittal plane, inversion / eversion in the coronal plane and internal / external rotation around the longitudinal axis (horizontal plane) of the human body, and the instantaneous posture of the talus is related to the three macroscopic movement angles. Therefore, in order to accurately describe the instantaneous movement law of the ankle joint, on the basis of the SS type ankle bone structure, the effect of the ankle tissue ligaments is considered, and the ankle joint rehabilitation robot of the present application is proposed.

[0044] When the above-mentioned rehabilitation robot is used for ankle joint rehabilitation training, a "foot-talus correlation motion model" is constructed to describe the correlation between the ankle talus and foot movement, that is, a human-machine system model. The fixed coordinate system o1-x1y1z1 of the rehabilitation robot is defined as follows: its origin coincides with the fixed sphere center O1, the z1 axis is perpendicular to the moving platform and points downward, the y1 axis coincides with the rotation axis of the first link 502 of the third branch chain and the third branch rigid-flexible coupling module 503, and the x1 axis is determined by the right-hand rule; the dynamic coordinate system o2-x2y2z2 of the rehabilitation robot is defined as follows: its origin coincides with the dynamic sphere center O2, the z2 axis is perpendicular to the moving platform and points downward, the x2 axis coincides with the rotation axis of the right side of the upper end of the third link 505 of the third branch chain and the right side of the other end of the second link 504 of the third branch chain, and the y2 axis is determined by the right-hand rule.

[0045] The foot posture matrix is ​​expressed as:

[0046] R Foot =Rot(x1,α)Rot(y1,β)Rot(z1,γ) (1)

[0047]

[0048] Where: Rot(x1,α), Rot(y1,β), and Rot(z1,γ) are the rotation matrices of the foot around the axes of the fixed coordinate system. α, β, and γ are the rotation angles of the foot around the axes of the fixed coordinate system, that is, the dorsiflexion / plantar flexion, inversion / eversion, and internal / external rotation angles of the ankle joint, α∈(-30°,45°), β∈(-22°,22°), and γ∈(-36°,36°).

[0049] The talus posture matrix is ​​expressed as:

[0050] R Talus =Rot(x1,α T )Rot(y1,β T )Rot(z1,γ T )(3)

[0051] Where: Rot(x1,α T )、Rot(y1,β T ) and Rot(z1,γ T ) is the rotation matrix of the talus around the axes of the fixed coordinate system, α T , β T and γ T The rotation angles of the talus around the axes of the fixed coordinate system, namely the dorsiflexion / plantar flexion, valgus / eversion, and internal / external rotation angles of the talus;

[0052] The pose transformation matrix of the moving coordinate system relative to the fixed coordinate system can be used to describe the instantaneous motion of the ankle joint, so it is defined as the "ankle joint motion matrix" and is expressed as:

[0053]

[0054] p Talus =R Talus (0,0,l) T (5)

[0055] Where: p Talus is the position vector of the tibiotalar joint center in the fixed coordinate system, and l is the length of the talus;

[0056] Substituting formula (3) into formula (5), it is not difficult to find that the vector p Talus γ and talus internal / external rotation angle T Irrelevant, i.e. γ T It does not affect the ankle joint motion description, so only the angle α T and β T were defined as talar motion parameters, and the rotation angles α, β, and γ were defined as foot posture parameters;

[0057] The talus posture parameter (α T / β T The function model of the change of α / β / γ with the foot posture parameters is defined as the "foot-talar correlation motion model". Since the dorsiflexion and eversion of the talus have the highest linear correlation with the dorsiflexion and eversion angles of the foot, respectively, the foot-talar correlation motion model is expressed as:

[0058]

[0059] Where: k α 、k β is the scale factor, E α (α,β,γ),E β (α, β, γ) is the error function;

[0060] To ensure the structural symmetry of the rehabilitation robot, the axis O1A0 coincides with the z1 axis of the fixed coordinate system, and the axes O1A1 and O1A2 are symmetrically arranged about the plane y1o1z1. A0 is the connection center of the third link 505 of the third branch chain and the moving platform 2, A1 is the rotation center of the first branch chain drive motor 301 and the first link 302 of the first branch chain, and A2 is the rotation center of the second branch chain drive motor and the first link of the second branch chain. Therefore, the axis O1A i (i=0,1,2) unit vector a in the fixed coordinate system i It can be expressed in spherical coordinates as:

[0061]

[0062] Where: is the angle between the unit vector a1 and the x1 axis, is the angle between the projection of the unit vector a1 on the surface y1o1z1 and the z1 axis, the sine and cosine values of the included angle the sine and cosine values of the included angle the sine and cosine values of the included angle the sine and cosine values of the included angle

[0063] axis O2C0 coincides with x2 axis, axis O2C1 and O2C2 are symmetrically arranged about plane y2o2z2, C0 is the rotation center of the right side of the third branch second link and the right side of the third branch third link, C1 is the rotation center of the first branch second link and the moving platform, C2 is the rotation center of the second branch second link and the moving platform; therefore, axis O2C i unit vector c i in the fixed coordinate system can be expressed by spherical coordinates as follows:

[0064]

[0065] wherein: is the included angle between unit vector c1 and x2 axis, is the included angle between the projection of unit vector c1 on plane y2o2z2 and x2 axis, the sine and cosine values of the included angle the sine and cosine values of the included angle the sine and cosine values of the included angle the sine and cosine values of the included angle

[0066] axis O1B Ui is parallel to O2B Li (i=0,1,2), B Ui is the rotation center of the ith branch first link and the rigid-flexible coupling module, B Li is the rotation center of the ith branch rigid-flexible coupling module and the second link, therefore, axis O1B Ui unit vector b i in the fixed coordinate system is expressed as:

[0067] b i =(b i1 ,b i2 ,b i3 ) T (9)

[0068] According to the pose transformation matrix of the moving coordinate system relative to the fixed coordinate system, the unit vector coordinates of axis O2C i in the fixed coordinate system can be calculated as:

[0069] O2C i =R Foot ×c=(c1,c2,c3) T (10)

[0070] axis O1Ai and O2C i is d i , which is expressed as:

[0071] d i = (d i1 , d i2 , d i3 ) = O1A i × O2C i = (a i2 c i3 - a i3 c i2 , a i3 c i1 - a i1 c i3 , a i1 c i2 - a i2 c i1 ), i = 0, 1, 2 (11)

[0072] According to the unit vector b i and the angles between the axis O1A i and O2C i , the angles are and respectively, the following equation can be established:

[0073]

[0074] wherein, and are the cosine values of the angles and respectively;

[0075] After calculation, it is obtained that:

[0076]

[0077]

[0078] In the rehabilitation exercise, the double center line O1O2 of the rehabilitation robot is always coincided with the talus of the ankle joint, thus according to the formula (4), the unit vector coordinates of the double center line O1O2 in the fixed coordinate system can be expressed as:

[0079]

[0080] In order to ensure the symmetry of the structure of the rehabilitation robot, the angles between the double center line O1O2 and the vectors b1and b2are equal, and are thus it is obtained that:

[0081]

[0082] After sorting, we can get:

[0083]

[0084]

[0085] Combined with formula (17), (18), (13), (14) and (11), the mapping relationship of the talus attitude parameters (α T / β T ) and the foot attitude parameters (α / β / γ) can be obtained, which is expressed as:

[0086]

[0087] In the formula: g α (·), g β (·) are mapping functions;

[0088] Known the talus attitude parameters (α T / β T ) and the foot attitude parameters (α / β / γ), the structure parameters of the rehabilitation robot can be obtained according to formula (19) The optimization design of the rehabilitation robot is realized.

[0089] The unmentioned part of the present application is applicable to the prior art.

Claims

1. A rigid-flexible coupling ankle rehabilitation robot, comprising a fixed platform, a moving platform, a first branch chain, a second branch chain and a third branch chain; the three branch chains are connected with the fixed platform and the moving platform, the first branch chain and the second branch chain are the same in structure and symmetrically distributed on both sides of the third branch chain; characterized in that, the first branch chain comprises a first branch chain driving motor, a first branch chain first connecting rod, a first branch chain rigid-flexible coupling module and a first branch chain second connecting rod; the first branch chain driving motor is connected with the fixed platform, one end of the first branch chain first connecting rod is connected with the output shaft of the first branch chain driving motor, the other end of the first branch chain first connecting rod is rotationally connected with the first branch chain rigid-flexible coupling module, the first branch chain rigid-flexible coupling module is rotationally connected with one end of the first branch chain second connecting rod, and the other end of the first branch chain second connecting rod is rotationally connected with the middle rear part of the moving platform; the third branch chain comprises a third branch chain driving motor, a third branch chain first connecting rod, a third branch chain rigid-flexible coupling module, a third branch chain second connecting rod and a third branch chain third connecting rod; the third branch chain driving motor is located at the lower part of the fixed platform, the output shaft of the third branch chain driving motor is connected with one end of the third branch chain first connecting rod, the other end of the third branch chain first connecting rod is rotationally connected with the third branch chain rigid-flexible coupling module, the third branch chain rigid-flexible coupling module is rotationally connected with one end of the third branch chain second connecting rod, the other end of the third branch chain second connecting rod is rotationally connected with the upper ends of the third branch chain third connecting rod on both sides, and the lower end of the third branch chain third connecting rod is fixedly connected with the middle rear part of the moving platform; the first branch chain rigid-flexible coupling module and the third branch chain rigid-flexible coupling module are the same in structure and each comprise four connecting rods and a torsional spring; the four connecting rods are rotationally connected in sequence to form a parallelogram, and one torsional spring is installed at the connection between adjacent two connecting rods; the rehabilitation robot has a fixed ball center and a moving ball center, the driving motors of the three branch chains control the posture of the moving platform to realize the dorsiflexion / toe flexion, inversion / eversion and internal / external rotation of the ankle joint, the rigid-flexible coupling modules of the three branch chains adjust the position of the moving ball center through the torsional spring to make the moving ball center move on a spherical surface with the length of the talus as the radius to fit the position of the human subtalar joint; the rotation axes of the two ends of the first branch chain first connecting rod, the two ends of the second branch chain first connecting rod and the first connecting rod of the third branch chain and the third branch chain rigid-flexible coupling module intersect at the fixed ball center of the rehabilitation robot; the rotation axes of the two ends of the first branch chain second connecting rod, the two ends of the second branch chain second connecting rod, the two ends of the third branch chain second connecting rod and the third branch chain third connecting rod and the axis of the connecting hole of the third branch chain third connecting rod and the moving platform intersect at the moving ball center of the rehabilitation robot.

2. The rigid-flexible coupled ankle rehabilitation robot according to claim 1, characterized in that, The mapping relationship between the talus posture parameter (α T / β T ) of the rehabilitation robot and the foot posture parameter (α / β / γ) is shown in formula (19), and the rehabilitation robot structure parameter is obtained according to the mapping relationship, so that the structure optimization is realized. In the formula: g α (·), g β (·) is a mapping function, α T and β T are the rotation angles of the talus around the x and y axes of the fixed coordinate system, and α, β and γ are the rotation angles of the foot around the x, y and z axes of the fixed coordinate system, (b 11 , b 12 , b 13 ) T is the unit vector b1 of the axis O1B U1 in the fixed coordinate system, (b 21 , b 22 , b 23 ) T is the unit vector b2 of the axis O1B U2 in the fixed coordinate system, is the angle between the unit vector a1 of the axis O1A1 in the fixed coordinate system and the x axis of the fixed coordinate system, is the angle between the projection of the unit vector a1 on the yoz plane of the fixed coordinate system and the z axis of the fixed coordinate system, is the angle between the unit vector c1 of the axis O2C1 in the fixed coordinate system and the x axis of the fixed coordinate system, is the angle between the projection of the unit vector c1 on the yoz plane of the fixed coordinate system and the x axis of the fixed coordinate system, and are the angles between the unit vector b i and the axes O1A i and O2C i , is the angle between the double center line O1O2 and the unit vector b1 or b2, O1 is the fixed center of the rehabilitation robot, O2 is the moving center of the rehabilitation robot, b i is the unit vector b1 of the axis O1B Ui in the fixed coordinate system, B Ui is the rotation center of the i-th first connecting rod and the first branch chain rigid-flexible coupling module, A i is the rotation center of the i-th branch chain driving motor and the first connecting rod, C i is the rotation center of the i-th second connecting rod and the moving platform, is the cosine value of the angle ; the origin of the fixed coordinate system is located at the fixed center of the rehabilitation robot, the z axis is perpendicular to the moving platform downward, the y axis coincides with the rotation axis of the first connecting rod of the third branch chain and the rotation axis of the rigid-flexible coupling module of the third branch chain, and the x axis complies with the right-hand rule; the origin of the moving coordinate system is located at the moving center of the rehabilitation robot, the z axis is perpendicular to the moving platform downward, the x axis coincides with the rotation axis of the right side of the upper end of the third connecting rod of the third branch chain and the right side of the other end of the second connecting rod of the third branch chain, and the y axis complies with the right-hand rule.

3. The rigid-flexible coupled ankle rehabilitation robot according to claim 2, wherein, The unit vector b i satisfies the equation: wherein: (a i1 , a i2 , a i3 ) are the coordinates of the unit vector b i in the fixed coordinate system, (b i1 , b i2 , b i3 ) T are the coordinates of the unit vector b i , (c i1 , c i2 , c i3 ) are the coordinates of the unit vector b i in the fixed coordinate system, and is the cosine of the angle , and is the cosine of the angle .

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