CN108245373A - A kind of ankle joint rehabilitation device of six cradle heads axis junction - Google Patents

Abstract

The invention relates to an ankle joint rehabilitation device with six rotating joint axes converging. The ankle joint rehabilitation device includes a moving platform, three motion branch chains, three motor drive units, three lead screw transmission units and a base. The moving platform includes an adjustable foot baffle, an up and down adjustment device, an upper platform and a lower platform. The position of the human ankle joint on the upper platform can be adjusted through the adjustable foot baffle and the up and down adjustment device. The three motion branch chains are evenly arranged on the moving platform. Between the platform and the lead screw drive unit, 3 lead screw drive units are evenly arranged on the base through screws, and 3 motor drive units are connected to the lead screw drive unit through couplings. Through the above structure, the present invention can meet the requirements of different patients for ankle joint rehabilitation. The structure is simple, and the rotation of the moving platform in three mutually orthogonal directions can be realized. Overlap effectively reduces the risk of secondary injury to the patient.

Description

An ankle joint rehabilitation device with six rotating joint axes converging

technical field

The invention relates to an ankle joint rehabilitation device, in particular to a parallel mechanism for assisting ankle joint rehabilitation training.

Background technique

As one of the weight-bearing joints of the human body, the ankle joint is the hub of contact between the human body and the ground, and can help the human body complete daily actions such as standing and walking. Ankle joint injury is the most common form of injury in life. Insufficient ankle muscle strength, poor stability and coordination are the main causes of ankle sprains. Moreover, it is not easy to heal after injury, and it is easy to form swelling and chronic pain. Most of them come from people with sports injuries, the elderly, and patients with hemiplegia caused by cardiovascular and cerebrovascular diseases. It not only affects the normal life and work of patients, but if the treatment is not timely or thorough, it is easy to cause secondary sprains, causing ankle joint dysfunction, and serious will affect walking function. Rehabilitation after ankle sprain can prevent necrotic soft tissue adhesion, improve ankle muscle strength, stability and coordination of ankle joint, and restore ankle joint function.

The ankle joint rehabilitation device requires that the rotation center of the moving platform and the human ankle joint motion center always coincide during the rehabilitation training process. Otherwise, during the rehabilitation exercise process, the human ankle joint must move while the mechanism rotates, and then the calf will follow. , If the coordination of the calf is not in place, the angle of movement will not be reached and the progress of rehabilitation will be affected, and the second injury of the ankle joint will be caused in severe cases. At the same time, the moving platform is required to have three degrees of freedom, and the structure and control are relatively simple. Insufficient or redundant degrees of freedom of the mechanism will affect the rehabilitation effect, and redundant motors will increase the difficulty of control.

Contents of the invention

The object of the present invention is to provide an ankle joint rehabilitation device in which the axes of six rotational joints converge, so as to solve the above problems.

An embodiment of the present invention provides an ankle joint rehabilitation device with six rotating joint axes converging, which is characterized in that the ankle joint rehabilitation device includes a moving platform, 3 motion branch chains, 3 motor drive units, and 3 lead screws The transmission unit and the base, the three motion branch chains include the first motion branch chain, the second motion branch chain, and the third motion branch chain, and the three motor drive units include the first motor drive unit, the second motor drive unit, and the third motor drive unit. The motor drive unit, the three lead screw transmission units include a first lead screw drive unit, a second lead screw drive unit, and a third lead screw drive unit. The ankle joint rehabilitation device contains three uniformly arranged branches, and each branch includes a one-to-one corresponding motor drive unit, screw drive unit and kinematic branch chain.

Furthermore, three evenly arranged branches connect the moving platform and the base, and the motor drive unit in each branch drives the corresponding screw drive unit, and the moving platform completes a three-dimensional spatial rotation around a fixed point through the movement of the moving branch chain.

Further, the motor drive unit is connected to the lead screw transmission unit through a coupling, and the motor and the connecting frame are respectively fixedly connected to the base through a fixing frame to support the motor drive unit.

Further, the three lead screw transmission units are evenly arranged on the base, and are fixedly connected with the base by screws.

Further, the three motion branch chains are evenly arranged between the moving platform and the three screw drive units, and all of them are CRU branch chains arranged obliquely, including a cylindrical pair, a rotating pair and a Hooke pair, and the cylindrical pair is installed on the upper end of the moving pair , the Hooke vice is installed at the lower end of the mobile vice.

Further, in the three motion branch chains, the axes of the six rotating joints meet at the center of rotation of the moving platform, and the six rotating joints include the first rotating joint of the first motion branch chain, the fourth rotating joint of the first motion branch chain, the second The first rotation joint of the motion branch chain, the fourth rotation joint of the second motion branch chain, the first rotation joint of the third motion branch chain, and the fourth rotation joint of the third motion branch chain.

Compared with the prior art, the beneficial effect of the present invention is that the structure and control of the device are relatively simple, and it has three-dimensional rotational freedom in space, which just meets the needs of ankle joint rehabilitation. The coincidence of joint motion centers greatly reduces the risk of secondary injury to the patient.

Description of drawings

Fig. 1 is the axonometric view of a kind of ankle rehabilitation device of the present invention;

Fig. 2 is a side view of an ankle joint rehabilitation device of the present invention;

Fig. 3 is an axonometric view of the motor drive unit;

Fig. 4 is an axonometric view of the screw drive unit;

Fig. 5 is a cross-sectional view and a partial enlarged view of the screw drive unit on the A-A plane;

Figure 6 is an axonometric view of the first kinematic branch;

Figure 7 is an axonometric view of a second kinematic branch;

Figure 8 is an axonometric view of a third kinematic branch;

Fig. 9 is a cross-sectional view of the first kinematic branch chain on the B-B plane;

Fig. 10 is a sectional view of the first kinematic branch chain on the C-C plane;

Figure 11 is an axonometric view of the moving platform;

Figure 12 is a left view and an exploded view of the moving platform;

Fig. 13 is a schematic diagram of the working principle and mechanism of an ankle joint rehabilitation device according to the present invention.

Detailed ways

The present invention will be described in detail below in conjunction with the implementations shown in the drawings, but it should be noted that these implementations are not limitations of the present invention, and those of ordinary skill in the art based on the functions, methods, or structures of these implementations All equivalent transformations or substitutions are within the protection scope of the present invention.

Referring to Figures 1 to 13, Figure 1 is an axonometric view of an ankle joint rehabilitation device of the present invention, Figure 2 is a side view of an ankle joint rehabilitation device of the present invention, and Figure 3 is an axonometric view of a motor drive unit , Fig. 4 is an axonometric view of the screw transmission unit, Fig. 5 is a cross-sectional view and a partial enlarged view of the screw transmission unit on the A-A plane, Fig. 6 is an axonometric view of the first kinematic branch chain, and Fig. 7 is a second kinematic branch The axonometric view of the chain, Fig. 8 is the axonometric view of the third kinematic branch chain, Fig. 9 is the sectional view of the first kinematic branch chain on the B-B plane, Fig. 10 is the sectional view of the first kinematic branch chain on the C-C plane, Fig. 11 is As for the axonometric view of the moving platform, Fig. 12 is a left view and an exploded view of the moving platform, and Fig. 13 is a schematic diagram of the working principle of an ankle joint rehabilitation device of the present invention.

This embodiment provides an ankle joint rehabilitation device in which six rotating joint axes converge, as shown in Figures 1 to 13, the ankle joint rehabilitation device includes a moving platform 67, 3 motion branch chains, 3 motor drive units, 3 lead screw transmission units and base 1, 3 motion branch chains including the first motion branch chain 21, the second motion branch chain 24, and the third motion branch chain 27, and 3 motor drive units including the first motor drive unit 19 , the second motor drive unit 22 , the third motor drive unit 25 , and the three lead screw drive units include a first lead screw drive unit 20 , a second lead screw drive unit 23 , and a third lead screw drive unit 26 .

In this embodiment, as shown in FIG. 1, FIG. 2 and FIG. 3, the first motor drive unit 19 includes a motor 28, a motor fixing frame 32, a planetary reducer 29, a motor coupling 31, a connecting frame 30 and a connection Frame fixing frame 33. One end of the motor fixing frame 32 is fixedly connected to the first motor drive unit 19, and the other end is fixedly connected to the bottom of the base 1 to support the first motor drive unit 19. The motor coupling 31 is coupled to the lead screw Cooperate with the gear 39 to transmit the output of the motor. The connecting frame 30 is fixedly connected between the planetary reducer 29 and the front block 34 of the first screw drive unit 20, and connects the first motor drive unit 19 and the first screw drive unit. 20, one end of the connecting frame fixing frame 33 is fixedly connected to the first motor drive unit 19, and the other end is fixedly connected to the bottom of the base 1 to support the first motor drive unit 19. Because the second motor drive unit 22, the third motor drive unit 25 and the first motor drive unit 19 have the same installation structure and connection mode, therefore, the installation mode of the second motor drive unit 22 and the third motor drive unit 25 Not described repeatedly.

In this embodiment, as shown in Fig. 1, Fig. 2, Fig. 4 and Fig. 5, the first lead screw transmission unit 20 includes a front stopper 34, a rear stopper 35, a guide rail 36, a guide rail slider 37, a lead screw 38. Lead screw coupling 39, angular contact ball bearing 40, lead screw bearing end cover 41 and dust cover 42, the guide rail 36 is fixedly connected between the front stopper 34 and the rear stopper 35 by screws, and the guide rail The slide block 37 slides on the guide rail 36, and its displacement is limited by the front block 34 and the rear block 35. The guide rail slide block 37 includes a threaded end slide block 43 and a middle slide block 44. 34. There are through holes on the rear stopper 35 and the guide rail slider 37, the screw 38 passes through the through hole, is supported by two angular contact ball bearings 40, and cooperates with the threaded end slider 43, so The screw coupling 39 cooperates with the motor coupling 31 to transmit the output of the motor. Since the second screw drive unit 23 and the third screw drive unit 26 have the same installation structure and connection mode as the first screw drive unit 20, the second screw drive unit 23 and the third screw drive unit The installation method of the unit 26 is not described repeatedly.

In this embodiment, as shown in Fig. 1, Fig. 2, Fig. 6, Fig. 7, Fig. 8, Fig. 9 and Fig. 10, the first kinematic branch chain 21 includes the first kinematic branch chain cylinder pair C1, the first kinematic branch chain Branch chain revolving pair R1 and the first movement branch chain Hooke pair U1, the first movement branch chain guide rail slider 4, the first movement branch chain bearing seat 5, the first movement branch chain connecting rod 6, the first movement branch chain Connecting rod two 7, connecting rod three 8 of the first motion branch chain, the first motion branch chain cylinder pair C1 is installed on the bottom of the first motion branch chain rotation pair R1, and the first motion branch chain Hooke pair U1 is installed On the upper part of the first kinematic branch chain rotation pair R1, the first kinematic branch chain cylinder pair C1 is composed of the first kinematic branch chain moving joint P1 and the first kinematic branch chain first rotation joint K11, which has a degree of freedom of movement and One degree of freedom of rotation, the first motion branch chain moving joint P1 includes the first motion branch chain guide rail slider 4 and the lead screw 38, which converts the rotation of the motor into linear motion, and the first motion branch chain rotation pair R1 is composed of The first kinematic branch chain is composed of the second rotary joint K12, which has one rotational degree of freedom. The first kinematic branch chain second rotary joint K12 includes the first kinematic branch chain connecting rod one 6 and the first kinematic branch chain connecting rod two 7 , the second revolving joint rotating shaft 45, the second revolving joint deep groove ball bearing 46, the sleeve 47, the flat key 48, the circlip 49 and the second revolving joint bearing end cap 50, the first kinematic branch chain connecting rod 27 includes two connecting thin plates 51 symmetrically arranged, and the first kinematic branch Hooke pair U1 is composed of the first kinematic branch third rotary joint K13 and the first kinematic branch fourth rotary joint K14 whose axes are perpendicular to each other , has two rotational degrees of freedom, and the fourth rotary joint K14 of the first motion branch chain includes the first motion branch chain connecting rod 38, the first connecting rod 52 of the lower platform, the fourth rotary joint deep groove ball bearing 55, the bearing The washer 56 and the fourth rotary joint bearing end cover 58, the first kinematic branch link three 8 directly serve as the fourth rotary joint rotation shaft 57, due to the first kinematic branch first rotary joint K11, the first kinematic The installation structure and connection method of the third rotation joint K13 of the branch chain and the second rotation joint K12 of the first motion branch chain are exactly the same. Therefore, the first rotation joint K11 of the first motion branch chain and the third rotation joint of the first motion branch chain The installation method of joint K13 is not described repeatedly.

Described second kinematic branch chain 24 comprises the second kinematic branch chain cylinder pair C2, the second kinematic branch chain rotation pair R2 and the second kinematic branch Hooke pair U2, the second kinematic branch chain guide rail slider 9, the second kinematic branch chain Branch chain bearing seat 10, second motion branch chain connecting rod one 11, second motion branch chain connecting rod two 12, second motion branch chain connecting rod three 13, the second motion branch chain cylinder pair C2 is formed by the second motion The branch chain moving joint P2 is composed of the second motion branch chain first rotation joint K21, and the second motion branch chain rotation pair R2 is composed of the second motion branch chain second rotation joint K22, and the second motion branch chain Hooke The pair U2 is composed of the second kinematic branch chain third rotary joint K23 and the second kinematic branch chain fourth rotary joint K24 whose axes are perpendicular to each other. The third kinematic branch chain 27 includes the third kinematic branch chain cylinder pair C3, the third kinematic branch chain Motion branch chain rotation pair R3 and the third motion branch chain Hooke pair U3, the third motion branch chain guide rail slider 14, the third motion branch chain bearing seat 15, the third motion branch chain connecting rod 16, the third motion branch Chain connecting rod two 17, third motion branch chain connecting rod three 18, the third motion branch chain cylinder pair C3 is composed of the third motion branch chain moving joint P3 and the third motion branch chain first rotating joint K31, the The third kinematic branch chain revolving pair R3 is composed of the second kinematic joint K32 of the third kinematic branch chain. The fourth rotary joint K34 of the motion branch chain is composed. Since the joints of the second kinematic branch chain 24 and the third kinematic branch chain 27 are completely the same as the joint installation structure and connection mode of the first kinematic branch chain 21, the second kinematic branch chain 24 and the third kinematic branch chain The joint installation and connection methods of the chain 27 are not described repeatedly.

In this embodiment, as shown in Fig. 1, Fig. 2, Fig. 11 and Fig. 12, the moving platform includes an adjustable foot board 59, an up and down adjusting device 62, an upper platform 3 and a lower platform 2, and the adjustable foot The baffle 59 moves a limited distance on the upper platform 3 through its own guide rail 60 to adapt to the foot size of different patients, and it is tightened by adjusting the screw 61 to prevent the adjustable foot baffle 59 from loosening during the rehabilitation exercise. The upper platform 3 is connected with the lower platform 2 through an up and down adjustment device 62. The up and down adjustment device 62 includes an up and down adjustment screw 63, a thrust ball bearing 64 and an upper platform bearing end cover 65, and the upper and lower platforms are adjusted by the up and down adjustment screw 63. The relative height is to adapt to the ankle height of different patients. The lower platform 2 is fixedly connected with the first connecting rod 52 of the lower platform, the second connecting rod 53 of the lower platform and the third connecting rod 54 of the lower platform.

In this embodiment, as shown in FIG. 13 , it is a schematic diagram of the working principle of the device, and the three kinematic branch chains (21, 24, 27) are arranged obliquely. During the rehabilitation exercise, the three kinematic branch chains (21 , 24, 27), the axis of the second rotary joint (K12, K22, K32) is always parallel to the axis of the third rotary joint (K13, K23, K33) and perpendicular to the plane of the kinematic branch chain, and the three kinematic branch chains In (21, 24, 27), the axis of the first rotary joint (K11, K21, K31) and the axis of the fourth rotary joint (K14, K24, K34) always meet at the center of rotation 66 of the moving platform, and the moving platform 67 revolves around this Rotate in 3 dimensions at a fixed point.

The present invention provides an ankle joint rehabilitation device in which the axes of six rotating joints converge, which has the following beneficial effects:

1) The control and structure of the device are simple and easy to use.

2) The device can adjust the front-back distance and up-down distance from the moving platform to the rotation center according to the needs of different patients.

3) The rotation center of the moving platform of the device always coincides with the movement center of the human ankle joint during the rehabilitation exercise, which effectively reduces the risk of secondary injury of the patient.

The series of detailed descriptions listed above are only specific descriptions for feasible implementations of the present invention, and they are not intended to limit the protection scope of the present invention. Any equivalent implementation or implementation that does not depart from the technical spirit of the present invention All changes should be included within the protection scope of the present invention.

It will be apparent to those skilled in the art that the invention is not limited to the details of the above-described exemplary embodiments, but that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Accordingly, the embodiments should be regarded in all points of view as exemplary and not restrictive, the scope of the invention being defined by the appended claims rather than the foregoing description, and it is therefore intended that the scope of the invention be defined by the appended claims rather than by the foregoing description. All changes within the meaning and range of equivalents of the elements are embraced in the present invention.

Claims (10)

1. An ankle joint rehabilitation device where six rotating joint axes converge, it is characterized in that: the ankle joint rehabilitation device includes a moving platform, 3 motion branch chains, 3 motor drive units, 3 screw drive units and a base , the 3 motion branch chains include the first motion branch chain, the second motion branch chain, and the third motion branch chain, and the 3 motor drive units include the first motor drive unit, the second motor drive unit, and the third motor drive unit, 3 A screw drive unit includes a first screw drive unit, a second screw drive unit, and a third screw drive unit; The ankle joint rehabilitation device contains three evenly distributed branches, and each branch includes a one-to-one corresponding motor drive unit, screw drive unit and kinematic branch chain; Three symmetrically distributed branches connect the moving platform and the base, and the motor drive unit in each branch drives the corresponding screw drive unit, and the moving platform completes the three-dimensional rotation around the fixed point through the movement of the moving branch chain; The motor drive unit is connected to the screw drive unit through a coupling, and the motor and the connecting frame are each fixedly connected to the base through a fixing frame to support the motor drive unit; 3 lead screw transmission units are evenly arranged on the base, and fixedly connected with the base by screws; The 3 motion branch chains are evenly arranged between the moving platform and the 3 lead screw transmission units, and they are CRU branch chains arranged obliquely, including a cylindrical pair, a revolving pair and a Hooke pair. The cylindrical pair is installed on the upper end of the moving pair. The gram pair is installed at the lower end of the mobile pair. 2. The ankle joint rehabilitation device according to claim 1, characterized in that: the screw drive unit adopts a screw and a double-sided guide rail structure, the unit is installed on the base, and the motor The rotation of the guide rail slider is converted into the linear motion of the guide rail slider, and the displacement of the guide rail slider is limited by the front and rear stoppers. The two ends of the screw are supported by angular contact ball bearings, and the extended end of the screw is connected with the coupling. 3. The ankle joint rehabilitation device according to claim 1, wherein the axes of the six rotating joints meet, wherein the first motion branch chain includes the first motion branch chain guide rail slider, the first motion branch chain Bearing housing, first motion branch link one, first movement branch link two, first movement branch link three, first movement branch guide rail slider consists of two threaded end sliders and a The middle slider, two threaded end sliders cooperate with the lead screw, the middle slider is fixed between the two end sliders, the first motion branch chain bearing seat is fixedly connected with the middle slider, the first motion branch chain is connected Rod two includes two symmetrically arranged connecting plates. 4. The ankle joint rehabilitation device according to claim 1 or 3, wherein the axes of the six rotating joints meet, wherein the first motion branch chain guide rail slider and the lead screw form the first motion branch chain moving joint, and the second A motion branch chain bearing block and the first motion branch chain connecting rod constitute the first rotation joint of the first motion branch chain. It constitutes the first kinematic branch chain cylinder pair, which has one degree of freedom of movement and one degree of freedom of rotation. The first kinematic branch chain connecting rod 1 and the first kinematic branch chain connecting rod 2 constitute the second rotational joint of the first kinematic branch chain, that is, the first The motion branch chain revolving pair has one degree of freedom of rotation, the first motion branch chain connecting rod two and the first motion branch chain connecting rod three constitute the third rotation joint of the first motion branch chain, the first motion branch chain connecting rod three and the lower The first connecting rod of the platform constitutes the fourth rotation joint of the first motion branch chain, and the axis of the third rotation joint of the first motion branch chain is perpendicular to the axis of the fourth rotation joint of the first motion branch chain, which together constitute the first motion branch chain tiger The gram pair has two rotational degrees of freedom. The upper end of the first kinematic branch chain is connected to the lower platform through the first kinematic branch Hooke pair, and the lower end of the first kinematic branch chain is connected to the lead screw through the first kinematic branch cylinder pair. , in the rehabilitation exercise, the axis of the second rotation joint of the first motion branch is always parallel to the axis of the third rotation joint of the first motion branch, and the axis of the first rotation joint of the first motion branch is parallel to the axis of the first rotation joint of the first motion branch The axes of the four rotating joints always meet at the center of rotation of the moving platform. 5. The ankle joint rehabilitation device with six rotating joint axes meeting according to claim 1, characterized in that: the second kinematic branch chain includes a second kinematic branch chain guide rail slider, a second kinematic branch chain connected in sequence Bearing housing, second motion branch link one, second movement branch link two, second movement branch link three, second movement branch guide rail slider consists of two threaded end sliders and a The middle slider, two threaded end sliders cooperate with the lead screw, the middle slider is fixed in the middle of the two end sliders, the second motion branch chain bearing seat is fixedly connected with the middle slider, the second motion branch chain is connected Rod two includes two symmetrically arranged connecting plates. 6. An ankle joint rehabilitation device with six rotating joint axes meeting according to claim 1 or 5, characterized in that: the second kinematic branch chain guide rail slider and the lead screw constitute the second kinematic branch chain moving joint, and the second kinematic branch chain moving joint. The second kinematic branch chain bearing seat and the second kinematic branch chain connecting rod constitute the first rotary joint of the second kinematic branch chain, and the axis of the second kinematic branch chain moving joint coincides with the axis of the first kinematic joint of the second kinematic branch chain. It constitutes the second kinematic branch chain cylinder pair, which has one degree of freedom of movement and one degree of freedom of rotation. The second kinematic branch chain connecting rod 1 and the second kinematic branch chain connecting rod 2 constitute the second kinematic branch second rotary joint, namely the second kinematic branch chain. The motion branch chain revolving pair has one degree of freedom of rotation, the second motion branch chain connecting rod two and the second motion branch chain connecting rod three constitute the second motion branch chain third rotating joint, the second motion branch chain connecting rod three and the lower motion branch chain link three The second connecting rod of the platform constitutes the fourth rotation joint of the second kinematic branch chain, the axis of the third rotation joint of the second kinematic branch chain is perpendicular to the axis of the fourth rotation joint of the second kinematic branch chain, and together constitute the second kinematic branch chain tiger The gram pair has two rotational degrees of freedom. The upper end of the second kinematic branch chain is connected to the lower platform through the second kinematic branch Hooke pair, and the lower end of the second kinematic branch chain is connected to the lead screw through the second kinematic branch chain cylinder pair. , in the rehabilitation exercise, the axis of the second rotation joint of the second motion branch is always parallel to the axis of the third rotation joint of the second motion branch, and the axis of the first rotation joint of the second motion branch is parallel to the axis of the second rotation joint of the second motion branch The axes of the four rotating joints always meet at the center of rotation of the moving platform. 7. The ankle joint rehabilitation device according to claim 1, wherein the axes of the six rotating joints meet, wherein the third kinematic branch chain includes the third kinematic branch chain guide rail slider, the third kinematic branch chain and the third kinematic branch chain Bearing housing, third motion branch link one, third movement branch link two, third movement branch link three, third movement branch rail slider consists of two threaded end sliders and a The middle slider, two threaded end sliders cooperate with the lead screw, the middle slider is fixed between the two end sliders, the third motion branch chain bearing seat is fixedly connected with the middle slider, the third motion branch chain is connected Rod two includes two symmetrically arranged connecting plates. 8. An ankle joint rehabilitation device with six rotating joint axes meeting according to claim 1 or 7, characterized in that: the third motion branch chain guide rail slider and the lead screw constitute the third motion branch chain moving joint, and the third motion branch chain moving joint The three-movement branch chain bearing seat and the third movement branch-chain connecting rod constitute the first rotating joint of the third movement branch chain, and the axis of the third movement branch-chain moving joint coincides with the axis of the first rotation joint of the third movement branch chain. It constitutes the third kinematic branch chain cylinder pair, which has one degree of freedom of movement and one degree of freedom of rotation. The third kinematic branch chain connecting rod 1 and the third kinematic branch chain connecting rod 2 constitute the second rotational joint of the third kinematic branch chain, that is, the third kinematic branch chain. The motion branch chain revolving pair has one rotational degree of freedom, the third motion branch chain connecting rod two and the third motion branch chain connecting rod three constitute the third motion branch chain third rotating joint, the third motion branch chain connecting rod three and the lower motion branch chain link three The third connecting rod of the platform constitutes the fourth rotational joint of the third kinematic branch chain, and the axis of the third kinematic branch joint is perpendicular to the axis of the fourth rotational joint of the third kinematic branch chain, forming the third kinematic branch chain together. Gram pair, with two rotational degrees of freedom, the upper end of the third kinematic branch chain is connected to the lower platform through the third kinematic branch Hooke pair, and the lower end of the third kinematic branch chain is connected to the lead screw through the third kinematic branch cylinder pair , in the rehabilitation exercise, the axis of the second rotation joint of the third motion branch is always parallel to the axis of the third rotation joint of the third motion branch, and the axis of the first rotation joint of the third motion branch is parallel to the axis of the third rotation joint of the third motion branch The axes of the four rotating joints always meet at the center of rotation of the moving platform. 9. An ankle joint rehabilitation device according to any one of claims 1-8, characterized in that: among the three motion branch chains, the axes of the six rotational joints converge on the moving platform Rotation center, 6 rotating joints including the first rotating joint of the first motion branch chain, the fourth rotating joint of the first motion branch chain, the first rotating joint of the second motion branch chain, the fourth rotating joint of the second motion branch chain, the third The first rotation joint of the motion branch chain and the fourth rotation joint of the third motion branch chain. 10. An ankle joint rehabilitation device according to any one of claims 1-9, characterized in that the moving platform includes an adjustable foot guard, an up and down adjustment device, an upper platform and a lower platform , the adjustable foot guard can move a limited distance on the upper platform through its own guide rail to adapt to the foot size of different patients. The upper platform is connected with the lower platform through an up and down adjustment device. The up and down adjustment device includes up and down adjustment screws, thrust ball bearings And the bearing end cover of the upper platform, adjust the relative height between the upper and lower platforms through the up and down adjustment screws to adapt to the ankle height of different patients, the first connecting rod between the lower platform and the lower platform, the second connecting rod of the lower platform and the third connecting rod of the lower platform Fixed connection.