A robot for ankle rehabilitation training

Abstract

This invention proposes a robot for ankle joint rehabilitation training, comprising: a foot platform, three RRS branches, a base, and adjustment devices. The top ends of the three RRS branches are connected to the foot platform, and the bottom ends are respectively connected to three adjustment devices. A drive motor is installed at the rotating joint in the middle of each RRS branch. The base includes a pedestal, which is a stepped top flange and a bottom flange. An internal gear is located inside the top flange, and a three-in-one cylindrical cam is located on the bottom flange. Three adjustment grooves of different shapes, spaced 120 degrees apart, are provided on the outer side of the pedestal. The adjustment devices are fixed to the top flange, and the internal gear is connected to the three adjustment devices. The rotation of the internal gear changes the tilt angle of the rotation axis at the bottom end of the RRS branch, allowing it to be adjusted between 0 and 90 degrees. Combined with the length adjustment of the three RRS branches by the three drive motors, the degrees of freedom of the foot platform are adjusted. This invention solves the problem that the degrees of freedom of ankle rehabilitation devices cannot be actively switched and adjusted, maintaining three degrees of freedom and covering six degrees of freedom.

Description

Technical Field

[0001] This invention relates to the field of rehabilitation equipment, and more specifically to a robot for ankle joint rehabilitation training. Background Technology

[0002] The ankle joint, a crucial weight-bearing and movement joint in the human body, often experiences functional impairment due to injuries, strokes, and postoperative rehabilitation. Scientific and timely rehabilitation training is essential for restoring ankle joint range of motion, muscle strength, and balance. In clinical rehabilitation practice, this primarily relies on one-on-one manual assisted training by therapists or traditional rehabilitation equipment. However, manual training requires the therapist's full involvement, is physically demanding, and the training intensity and joint range of motion largely depend on individual experience, making it difficult to guarantee consistency and precision.

[0003] From a biomechanical perspective, when the foot drives the ankle joint in rehabilitation training, the required degrees of freedom can be divided into six spatial degrees of freedom: three translational degrees of freedom (forward / backward, left / right, up / down) and three rotational degrees of freedom (dorsiflexion / plantar flexion, inversion / eversion, horizontal rotation). Rehabilitation equipment should be able to flexibly provide training modes with corresponding degrees of freedom according to the different recovery stages of the patient.

[0004] Currently, rehabilitation equipment for the ankle joint is mainly divided into two categories, both of which have structural defects. One category is single-degree-of-freedom devices (such as pedal trainers that only allow plantar flexion / dorsiflexion), which can only perform single rehabilitation movements in a specific dimension. Long-term use can easily lead to joint stiffness and muscle compensation, making it difficult to meet the multi-modal and multi-angle training requirements of functional rehabilitation. The other category is five-degree-of-freedom or six-degree-of-freedom parallel platforms (such as improved versions of the Stewart platform). Although theoretically they can achieve omnidirectional motion control, they pose serious safety hazards in actual rehabilitation. Redundant degrees of freedom become interfering factors, and unexpected multi-directional displacements can easily cause secondary injuries. Furthermore, the fixed mechanical configuration cannot adjust the rehabilitation mode according to the needs of the rehabilitation stage, and the reliability of the "virtual constraints" set at the software level is insufficient. Once out of control, it will directly generate mechanical risks.

[0005] In summary, the core deficiency of the two existing types of rehabilitation equipment lies in the lack of a physical-level active switching mechanism for degrees of freedom. Clinically, there is an urgent need for a reconfigurable rehabilitation robot that can achieve precise and safe rehabilitation training with fewer degrees of freedom, while also covering the full six-degree-of-freedom range of motion through physical-level degree-of-freedom switching. This would provide a variety of targeted fewer-degree-of-freedom rehabilitation training modes for different stages of rehabilitation. Summary of the Invention

[0006] To address the limitations of existing technologies in enabling targeted rehabilitation training with limited degrees of freedom, this invention proposes a robot for ankle joint rehabilitation training.

[0007] The technical solution of this invention is implemented as follows: A robot for ankle joint rehabilitation training includes: a foot platform, RRS branches, a base, and an adjustment device. The bottom end of the foot platform is connected to three RRS branches through three ball joints arranged in an equilateral triangle. The bottom end of each RRS branch is connected to an adjustment device through a revolute joint. A drive motor is installed at the revolute joint in the middle of each RRS branch. The base includes a base, an internal gear, and a three-in-one cylindrical cam. The base is configured as a stepped top flange and a bottom flange. The internal gear is located inside the top flange, and the three-in-one cylindrical cam is located on the bottom flange. Three different shaped adjustment grooves spaced 120 degrees apart are provided on its outer side. Three adjusting devices are evenly distributed on the top flange of the base and located inside the internal gear. Each adjusting device includes a fixed bracket, a rotating shaft bracket, a transmission mechanism, an adjusting gear, and a gear fork. The fixed bracket is fixed to the top flange of the base. The rotating shaft bracket is located at the top of the fixed bracket and is connected to the bottom end of an RRS branch. The transmission mechanism is located on the fixed bracket. The output shaft of the transmission mechanism is connected to the rotating shaft bracket, and the input shaft of the transmission mechanism is connected to the adjusting gear. The adjusting gear slides on the input shaft to engage or disengage with the internal gear. The gear fork is limited on the base. Two limiting baffles on one side of the gear fork are respectively limited to the two ends of the adjusting gear. The cylindrical protrusion on the other side is limited in an adjusting groove of a three-in-one cylindrical cam. The movement of the gear fork in the adjusting groove drives the adjusting gear to slide. The cylindrical protrusions of the three gear forks are respectively limited in the three adjustment slots of the three-in-one cylindrical cam. The different shapes of the three adjustment slots cause the three adjustment gears to move up and down as the three gear forks move in the three adjustment slots when the three-in-one cylindrical cam rotates. The three adjustment gears can simultaneously engage or disengage with the inner gear, or any one or two adjustment gears can engage with the inner gear while the other adjustment gears disengage from the inner gear. When the internal gear meshes with one, two, or three adjusting gears, the rotation of the internal gear drives the meshing adjusting gear to rotate. The rotational force of the adjusting gear is transmitted to the corresponding rotating shaft support through the transmission mechanism it is connected to. The rotation of the rotating shaft support changes the tilt angle of the rotating shaft at the bottom end of the connected RRS branch, so that the tilt angle of the rotating shaft is adjusted between 0 degrees and 90 degrees. The angle change of the tilt angle of the rotating shaft at the bottom end of the three RRS branches coordinates with the three drive motors to adjust the length of the three RRS branches, thereby adjusting the degree of freedom of the foot platform.

[0008] Preferably, the inner side of the base is provided with three evenly distributed radial slots extending to the top flange. Vertical slots are distributed on a pair of inner sidewalls of each radial slot adjacent to the outer side of the top flange. One of the gear forks is inserted into a pair of vertical slots for positioning. Each radial slot located on the inner side of the top flange can accommodate an adjusting gear.

[0009] Preferably, the transmission mechanism includes: a rocker arm, a connecting rod, a crank, a turbine, a turbine shaft, and a slide rail worm gear. The rotating shaft of the rocker arm is fixed to a rotating shaft support. The rotation of the rocker arm drives the rotating shaft support to rotate synchronously. One end of the connecting rod is connected to the rocker arm through a rotating joint, and the other end is connected to the crank through a rotating joint. The turbine shaft is installed below the fixed support. The crank and the turbine are mounted together on the turbine shaft and defined as a single unit. The slide rail worm gear is installed on the fixed support and meshes with the turbine. An adjusting gear is installed on the input shaft at the lower end of the slide rail worm gear. The adjusting gear rotates together with the slide rail worm gear and can slide on the input shaft.

[0010] Preferably, a marking symbol is provided on the top flange of the base, and at least four numerical symbols are provided on the upper surface of the three-in-one cylindrical cam. Each numerical symbol corresponds to the marking symbol and represents the connection state between the adjusting gears and the internal gear of the three adjusting devices. The four connection states include: the three adjusting gears are respectively engaged with the internal gear; the two adjusting gears are respectively engaged with the internal gear; the one adjusting gear is engaged with the internal gear; and the three adjusting gears are respectively disengaged from the internal gear.

[0011] Preferably, a groove is provided above the foot platform, and two bandages are fixed above the groove.

[0012] Preferably, of the three adjustment grooves, one adjustment groove is an arc-shaped curve with high ends and low middle, another adjustment groove is an arc-shaped curve with high end and low other end, and the third adjustment groove is a wave-shaped curve with high and low undulations.

[0013] The beneficial effects of this invention are as follows: The robot for ankle joint rehabilitation training of this invention, through the coordination of the adjustment device and the internal gears of the base, directly adjusts the tilt angle of the rotation axis at the bottom of the three RRS branches. Combined with the coordinated operation of the three drive motors, it enables the foot platform to maintain controlled movement of three degrees of freedom during training, while simultaneously possessing the ability to cover six degrees of freedom. This allows for targeted rehabilitation training while avoiding interference from redundant degrees of freedom. This design enables precise training with fewer degrees of freedom for different rehabilitation stages, and effectively eliminates interference from redundant degrees of freedom at the physical level, significantly improving the safety and targeting of training.

[0014] When it is necessary to change the rehabilitation training mode, the engagement state between the three adjustment devices and the internal gear is controlled by the three-in-one cylindrical cam on the base. Simply rotating the internal gear and controlling the three drive motors allows for flexible switching of degrees of freedom. This switching process achieves rapid and reliable conversion between different degrees of freedom modes without changing the overall structure of the robot.

[0015] Furthermore, the internal gear has the ability to disengage from any adjustment device, allowing for differentiated and independent adjustment of the rotation axis inclination at the bottom of the three RRS branches according to actual rehabilitation needs. This enables the invention to construct various forms and combinations of degree-of-freedom modes, greatly enriching the range of rehabilitation training programs and enhancing its adaptability to different patients and different stages of disease, thus possessing significant clinical application value. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the overall structure of the robot for ankle joint rehabilitation training according to the present invention; Figure 2 for Figure 1 The diagram shows the assembly of the base and adjustment device. Figure 3 for Figure 2 A partial assembly diagram of the base and adjustment device is shown; Figure 4 for Figure 3 The diagram shows the structure of the gear shift fork. Figure 5 for Figure 1 The diagram shows the overall structure of the base. Figure 6 for Figure 5 A schematic diagram of the radial groove structure of the base shown; Figure 7 for Figure 1 The diagram shows the structure of the regulating device. Figure 8 for Figure 1 The diagram shows the structure of the three-in-one cylindrical cam and the adjusting groove A. Figure 9 for Figure 1 The diagram shows the structure of the three-in-one cylindrical cam and the adjusting groove B. Figure 10 for Figure 1 The diagram shows the structure of the three-in-one cylindrical cam and the adjusting groove C. Figure 11 This is a schematic diagram of the motion state of the robot for ankle joint rehabilitation training of the present invention when the rotation axis at the bottom of the three RRS branches is tilted at 0 degrees. Figure 12This is a schematic diagram of the motion state of the robot for ankle joint rehabilitation training of the present invention when the rotation axis at the bottom of the three RRS branches is tilted at an angle of 45 degrees. Figure 13 This is a schematic diagram of the motion state of the robot for ankle joint rehabilitation training of the present invention when the rotation axis at the bottom of the three RRS branches is tilted at an angle of 90 degrees.

[0018] In the picture: 1. Foot platform; 2. RRS branch chain; 3. Base; 4. Adjustment device; 31. Base; 32. Internal gear; 33. Three-in-one cylindrical cam; 41. Fixed bracket; 42. Rotary shaft bracket; 43. Transmission mechanism; 44. Adjusting gear; 45. Gear shift fork; 311. Radial slot; 312. Vertical slot; 431. Rocker arm; 432. Connecting rod; 433. Crank; 434. Turbine; 435. Turbine shaft; 436. Slide rail worm gear. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example: Figures 1 to 10 The robot shown for ankle joint rehabilitation training includes: a foot platform 1, RRS branches 2, a base 3, and an adjustment device 4. The bottom end of the foot platform 1 is connected to three RRS branches 2 through three ball joints arranged in an equilateral triangle. The bottom end of one RRS branch 2 is connected to an adjustment device 4 through a rotating joint. A drive motor is installed at the rotating joint in the middle of each RRS branch 2. The base 3 includes a base 31, an internal gear 32, and a three-in-one cylindrical cam 33. The base 31 is configured as a stepped top flange and a bottom flange. The internal gear 32 is located inside the top flange. The three-in-one cylindrical cam 33 is located on the bottom flange. The three-in-one cylindrical cam 33 has three different shaped adjustment grooves spaced 120 degrees apart on its outer side. Three adjusting devices 4 are evenly distributed on the top flange of the base 31 and located inside the internal gear 32. Each adjusting device 4 includes a fixed bracket 41, a rotating shaft bracket 42, a transmission mechanism 43, an adjusting gear 44, and a gear fork 45. The fixed bracket 41 is fixed at the top flange of the base 31. The rotating shaft bracket 42 is located at the top of the fixed bracket 41 and is connected to the bottom end of an RRS branch chain 2. The transmission mechanism 43 is located on the fixed bracket 41. The output shaft of the output end of the transmission mechanism 43 is connected to the rotating shaft bracket 42. The input shaft of the input end of the transmission mechanism 43 is connected to the adjusting gear 44. The adjusting gear 44 slides on the input shaft to engage or disengage with the internal gear 32. The gear fork 45 is limited on the base 31. Two limiting baffles on one side of the gear fork are respectively limited at both ends of the adjusting gear 44. The cylindrical protrusion on the other side is limited in an adjusting groove of the three-in-one cylindrical cam 33. The movement of the gear fork 45 in the adjusting groove drives the adjusting gear 44 to slide. The cylindrical protrusions of the three gear forks 45 are respectively limited in the three adjustment slots of the three-in-one cylindrical cam. The different shapes of the three adjustment slots cause the three adjustment gears 44 to move up and down as the three gear forks move in the three adjustment slots when the three-in-one cylindrical cam 33 rotates. The three adjustment gears can simultaneously engage or disengage with the inner gear, or any one or two adjustment gears can engage with the inner gear while the other adjustment gears disengage from the inner gear. When the internal gear 32 meshes with one, two, or three adjusting gears 44, the rotation of the internal gear drives the meshing adjusting gear to rotate. The rotational force of the adjusting gear is transmitted to the corresponding rotating shaft support 42 through the transmission mechanism it is connected to. The rotation of the rotating shaft support changes the tilt angle of the rotating shaft at the bottom end of the connected RRS branch, so that the tilt angle of the rotating shaft is adjusted between 0 degrees and 90 degrees. The angle change of the tilt angle of the rotating shaft at the bottom end of the three RRS branches coordinates with the three drive motors to adjust the length of the three RRS branches, thereby adjusting the degree of freedom of the foot platform. The degree of freedom of the foot platform can be actively switched without changing the structure.

[0021] like Figure 6 As shown, the inner side of the base 31 has three evenly distributed radial slots 311 extending to the top flange. Vertical slots 312 are distributed on a pair of inner sidewalls of each radial slot 311 adjacent to the outer side of the top flange. A gear fork 45 is inserted into a pair of vertical slots for positioning. Each radial slot located inside the top flange can accommodate an adjusting gear 44. The structural design of the base satisfies both the positioning of the gear fork and the up-and-down movement of the adjusting gear driven by the gear fork to mesh with the internal gear, achieving synergy between the interacting structural parts.

[0022] like Figure 7As shown, the transmission mechanism 43 includes: a rocker arm 431, a connecting rod 432, a crank 433, a turbine 434, a turbine shaft 435, and a slide rail worm gear 436. The rotating shaft of the rocker arm 431 is fixed to the rotating shaft bracket 42. The rotation of the rocker arm drives the rotating shaft bracket to rotate synchronously. One end of the connecting rod 432 is connected to the rocker arm 431 through a rotating joint, and the other end is connected to the crank through a rotating joint. The turbine shaft 435 is installed below the fixed bracket 41. The crank 433 and the turbine 434 are jointly installed on the turbine shaft 435, and the crank and the turbine are defined as one unit. The slide rail worm gear 436 is installed on the fixed bracket 41 and meshes with the turbine 434. An adjusting gear 44 is installed on the input shaft at the lower end of the slide rail worm gear 436. The adjusting gear 44 rotates together with the slide rail worm gear 436. The adjusting gear 44 can slide on the input shaft as driven by the gear shift fork.

[0023] The slide rail worm and worm gear of the transmission mechanism have self-locking characteristics. After the adjusting gear disengages from the internal gear, the transmission mechanism self-locks. The adjusting gear rotates along with the internal gear, which drives the slide rail worm to rotate. The slide rail worm drives the worm gear to rotate, which in turn drives the worm gear to rotate. The worm gear and crank rotate together, which in turn drives the connecting rod to rotate. The connecting rod's rotation drives the rocker arm to rotate, which in turn drives the rotating shaft support to rotate. The rotating shaft support then drives the rotating shaft at the bottom of the RRS branch connected to it to rotate.

[0024] like Figure 3 , Figures 8 to 10 As shown, a marking symbol is provided on the top flange of the base 31, and at least four numerical symbols are provided on the upper surface of the three-in-one cylindrical cam 33. Each numerical symbol corresponds to a marking symbol, representing the connection state between the adjusting gears and the internal gear of the three adjusting devices. The four connection states include: three adjusting gears meshing with the internal gear, two adjusting gears meshing with the internal gear, one adjusting gear meshing with the internal gear, and three adjusting gears disengaging from the internal gear. The design of the marking symbol and numerical symbols allows for more intuitive observation and adjustment of the different motion states of the adjusting devices and internal gears, facilitating operation, and has no impact on the connection between the base and the adjusting devices.

[0025] like Figure 1 As shown, a groove is provided above the foot platform 1, and two bandages are fixed above the groove to fix the foot and limit the foot to the groove to prevent the foot from wobbling during rehabilitation training.

[0026] like Figures 8 to 10As shown, of the three adjusting grooves of the three-in-one cylindrical cam 33, one adjusting groove A is an arc-shaped curve with high ends and low middle, one adjusting groove B is an arc-shaped curve with one end high and the other end low, and one adjusting groove C is a wave-shaped curve with undulating highs and lows. When the gear forks on adjusting grooves A, B, and C are at their high points, the adjusting gear 44 connected to them meshes with the internal gear 32; when they are at their low points, they disengage. Adjusting grooves A, B, and C allow the three adjusting gears to simultaneously mesh with or disengage from the internal gear, or allow any one or two adjusting gears to mesh with the internal gear while the other adjusting gears disengage from the internal gear.

[0027] In use, first adjust the three-in-one cylindrical cam 33 on the base 31, adjust the internal gear 32 to mesh with the adjusting gears of the three adjusting devices 4, then rotate the internal gear 32 to drive the rotating shaft bracket 42 of the adjusting device 4, adjust the angle of the rotating shaft at the bottom of the three RRS branches 2, then control the drive motor in the middle of the three RRS branches to adjust the straight distance of the three RRS branches, and adjust the overall degree of freedom of the foot platform.

[0028] like Figure 11 As shown, when the rotation axis tilt angle at the bottom of the three RRS branches is 0 degrees, the drive motor is controlled to adjust the linear distance of the three RRS branches, controlling the foot platform to move vertically up and down along it, and controlling the foot platform to rotate along its lateral or longitudinal axis. At this time, the foot platform has 3 degrees of freedom: 2 rotations and 1 translation. When the foot platform rotates along its lateral axis, it can control the foot to perform plantar flexion and dorsiflexion rehabilitation training; when it rotates along its longitudinal axis, it can control the foot to perform inversion and eversion rehabilitation training; and when it performs translational movement in its vertical direction, it can perform vertical traction rehabilitation training for the ankle joint.

[0029] like Figure 12 As shown, when the rotation axis at the bottom of the three RRS branches is tilted at 45 degrees, the drive motor is controlled to adjust the linear distance between the three RRS branches, controlling the foot platform to rotate along its lateral and longitudinal axes, as well as its vertical direction. At this time, the foot platform has 3 degrees of freedom (3 rotations). When the foot platform rotates along its lateral axis, it can control the foot to perform plantar flexion and dorsiflexion rehabilitation training; when it rotates along its longitudinal axis, it can control the foot to perform inversion and eversion rehabilitation training; and when it rotates along its vertical direction, it can perform internal and external rotation rehabilitation training for the ankle joint.

[0030] like Figure 13As shown, when the rotation axis at the bottom of the three RRS branches is tilted at 90 degrees, the drive motor is controlled to adjust the linear distance between the three RRS branches, controlling the foot platform to translate along its lateral and longitudinal axes, and controlling the foot platform to rotate along its vertical direction. At this time, the foot platform has 2 translational and 1 rotational degrees of freedom. When the foot platform translates along its lateral axis, it can control the foot to perform lateral traction rehabilitation training on the ankle joint; when it translates along its longitudinal axis, it can control the foot to perform longitudinal traction rehabilitation training on the ankle joint; and when it rotates along its vertical direction, it can perform internal and external rotation rehabilitation training on the ankle joint.

[0031] The rotation axis tilt angles at the bottom ends of the three RRS branches are different, allowing for different modes of rehabilitation training. At the aforementioned three specific angles, the system can cover three translational degrees of freedom (anteroposterior, lateral, and vertical) and three rotational degrees of freedom (dorsiflexion / plantar flexion, inversion / eversion, and horizontal rotation) of the foot platform. The tilt angles of the rotation axes at the bottom ends of the three RRS branches can also be adjusted at different angles. In actual rehabilitation training, all six degrees of freedom are not performed simultaneously. The robot for ankle joint rehabilitation training of this invention can directly and actively switch between degree-of-freedom modes, constructing various forms and combinations of degree-of-freedom modes. This allows the foot platform to maintain controlled movement in three degrees of freedom throughout the training process, while simultaneously possessing the ability to cover all six degrees of freedom. The above description is merely a preferred embodiment of the invention and is not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A robot for ankle joint rehabilitation training, characterized in that, include: The foot platform, RRS branches, base, and adjustment device are provided. The bottom of the foot platform is connected to three RRS branches through three ball joints arranged in an equilateral triangle. The bottom of each RRS branch is connected to an adjustment device through a rotating joint. A drive motor is installed at the rotating joint in the middle of each RRS branch. The base includes a base, an internal gear, and a three-in-one cylindrical cam. The base is configured as a stepped top flange and a bottom flange. The internal gear is located inside the top flange, and the three-in-one cylindrical cam is located on the bottom flange. Three different shaped adjustment grooves spaced 120 degrees apart are provided on its outer side. Three adjusting devices are evenly distributed on the top flange of the base and located inside the internal gear. Each adjusting device includes a fixed bracket, a rotating shaft bracket, a transmission mechanism, an adjusting gear, and a gear fork. The fixed bracket is fixed to the top flange of the base. The rotating shaft bracket is located at the top of the fixed bracket and is connected to the bottom end of an RRS branch. The transmission mechanism is located on the fixed bracket. The output shaft of the transmission mechanism is connected to the rotating shaft bracket, and the input shaft of the transmission mechanism is connected to the adjusting gear. The adjusting gear slides on the input shaft to engage or disengage with the internal gear. The gear fork is limited on the base. Two limiting baffles on one side of the gear fork are respectively limited to the two ends of the adjusting gear. The cylindrical protrusion on the other side is limited in an adjusting groove of a three-in-one cylindrical cam. The movement of the gear fork in the adjusting groove drives the adjusting gear to slide. The cylindrical protrusions of the three gear forks are respectively limited in the three adjustment slots of the three-in-one cylindrical cam. The different shapes of the three adjustment slots cause the three adjustment gears to move up and down as the three gear forks move in the three adjustment slots when the three-in-one cylindrical cam rotates. The three adjustment gears can simultaneously engage or disengage with the inner gear, or any one or two adjustment gears can engage with the inner gear while the other adjustment gears disengage from the inner gear. When the internal gear meshes with one, two, or three adjusting gears, the rotation of the internal gear drives the meshing adjusting gear to rotate. The rotational force of the adjusting gear is transmitted to the corresponding rotating shaft support through the transmission mechanism it is connected to. The rotation of the rotating shaft support changes the tilt angle of the rotating shaft at the bottom end of the connected RRS branch, so that the tilt angle of the rotating shaft is adjusted between 0 degrees and 90 degrees. The angle change of the tilt angle of the rotating shaft at the bottom end of the three RRS branches coordinates with the three drive motors to adjust the length of the three RRS branches, thereby adjusting the degree of freedom of the foot platform.

2. The robot for ankle joint rehabilitation training according to claim 1, characterized in that, The base has three evenly distributed radial slots on its inner side, which extend to the top flange. Vertical slots are distributed on a pair of inner sidewalls of each radial slot adjacent to the outer side of the top flange. A gear fork is inserted into a pair of vertical slots for positioning. Each radial slot located on the inner side of the top flange can accommodate an adjusting gear.

3. The robot for ankle joint rehabilitation training according to claim 1, characterized in that, The transmission mechanism includes: a rocker arm, a connecting rod, a crank, a turbine, a turbine shaft, and a slide rail worm gear. The rotating shaft of the rocker arm is fixed to the rotating shaft bracket. The rotation of the rocker arm drives the rotating shaft bracket to rotate synchronously. One end of the connecting rod is connected to the rocker arm through a rotating joint, and the other end is connected to the crank through a rotating joint. The turbine shaft is installed below the fixed bracket. The crank and the turbine are mounted together on the turbine shaft and are constrained as one unit. The slide rail worm gear is installed on the fixed bracket and meshes with the turbine. An adjusting gear is installed on the input shaft at the lower end of the slide rail worm gear. The adjusting gear rotates together with the slide rail worm gear and can slide on the input shaft.

4. The robot for ankle joint rehabilitation training according to claim 1, characterized in that, A marking symbol is provided on the top flange of the base, and at least four numerical symbols are provided on the upper surface of the three-in-one cylindrical cam. Any numerical symbol corresponds to the marking symbol and represents the connection state of the adjusting gears and the internal gear of the three adjusting devices. The four connection states include: the three adjusting gears are engaged with the internal gear respectively; the two adjusting gears are engaged with the internal gear respectively; the one adjusting gear is engaged with the internal gear; and the three adjusting gears are disengaged from the internal gear respectively.

5. The robot for ankle joint rehabilitation training according to claim 1, characterized in that, A groove is provided above the foot platform, and two bandages are fixed above the groove.

6. The robot for ankle joint rehabilitation training according to claim 1, characterized in that, Of the three adjustment grooves, one adjustment groove is an arc-shaped curve with high ends and low middle, another adjustment groove is an arc-shaped curve with high end and low other end, and the third adjustment groove is a wave-shaped curve with high and low undulations.

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