A reconfigurable parallel mechanism for ankle joint rehabilitation

Abstract

The present invention is a reconfigurable ankle joint rehabilitation parallel mechanism, comprising a static platform, a dynamic platform, a 3R branch chain, and three metamorphic branches; the rear ends of the static platform and the dynamic platform are connected by the 3R branch chain, so that the mechanism has a fixed spherical center and a dynamic spherical center, the dynamic spherical center rotates spherically around the fixed spherical center, and the dynamic platform rotates spherically around the dynamic spherical center, and the distance between the two spherical centers is equal to the center distance between the tibiotalar joint and the subtalar joint of the ankle joint; the three metamorphic branches respectively connect the left and right sides and the front end of the static platform and the dynamic platform, and the No. 1 connecting rod of the metamorphic branch serves as an active component, enabling the metamorphic branch to realize the transformation from S pair to U pair and R pair, so that the mechanism has different motion modes. In each mode, each metamorphic branch is an SPU branch chain or a UPU branch chain. The metamorphic branch chain can realize the switching from S pair to U pair to adjust the position and posture of the dynamic platform, so that the mechanism has multiple motion modes to meet the training needs of different ankle injury types and different rehabilitation stages.

Description

Technical Field

[0001] The present invention belongs to the technical field of rehabilitation equipment, and in particular relates to a reconfigurable ankle joint rehabilitation parallel mechanism. Background Art

[0002] The ankle joint, the largest weight-bearing joint in the human body, serves as the interface between the body and the ground. A range of human movements, including standing, walking, running, squatting, and jumping, are all closely linked to the ankle joint, increasing the likelihood of ankle injury. The ankle joint consists of the tibiotalar joint and the subtalar joint. Both joints have a certain degree of mobility. The tibiotalar joint is primarily responsible for internal and external rotation and eversion, while the subtalar joint is primarily responsible for dorsiflexion and plantar flexion. Therefore, ankle movement can be considered a complex motion composed of these two joints. Most existing ankle rehabilitation robots fail to consider the kinematic coupling between the tibiotalar and subtalar joints, instead simply equating ankle movement to spherical motion. Consequently, inconsistencies between the mechanism's motion and the patient's ankle joint are common during rehabilitation, leading to significant human-machine interaction forces during training and potentially causing secondary injury to the patient.

[0003] There are many types of ankle injuries, including ankle ligament injuries and muscle injuries, which can cause patients to lose some or all of their ankle motion. If ankle injuries are not treated promptly or thoroughly, they can lead to laxity of the ankle ligaments and increase the likelihood of recurrent sprains. Training requirements vary depending on the type of injury and the stage of rehabilitation. For injuries to the ligaments and muscles associated with ankle dorsiflexion and plantar flexion, early rehabilitation exercises should focus on internal and external rotation, internal and external rotation, and dorsiflexion and plantar flexion exercises. In the middle stage of rehabilitation, exercises should focus on dorsiflexion and plantar flexion. In the late stage of rehabilitation, exercises should focus on dorsiflexion and plantar flexion, internal and external rotation, and internal and external rotation, as well as full range of motion. In the early stage of rehabilitation for injuries to the ligaments and muscles associated with the internal and external rotation of the ankle joint, the main focus should be on dorsiextension and plantar flexion rehabilitation exercises. In the middle stage of rehabilitation, the main focus should be on internal and external rotation, internal and external eversion, and internal and external rotation rehabilitation exercises. In the late stage of rehabilitation, the main focus should be on dorsiextension and plantar flexion, internal and external rotation, and full-range three-degree-of-freedom movements. However, most of the existing ankle rehabilitation robots have a single rehabilitation mode and cannot carry out targeted rehabilitation training, which can easily cause discomfort to the patient and even cause secondary injury to the patient. Therefore, the present invention designs a reconfigurable ankle rehabilitation parallel mechanism, which realizes multiple motion modes through the reconfiguration of the mechanism to meet the training needs of different ankle injury types and different rehabilitation stages. Summary of the Invention

[0004] In view of the deficiencies in the prior art, the technical problem to be solved by the present invention is a reconfigurable ankle joint rehabilitation parallel mechanism.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A reconfigurable ankle joint rehabilitation parallel mechanism includes a static platform and a dynamic platform; it is characterized in that the mechanism also includes a 3R branch chain and three metamorphic branches; the rear ends of the static platform and the dynamic platform are connected by the 3R branch chain, so that the mechanism has a fixed spherical center and a dynamic spherical center, the dynamic spherical center rotates spherically around the fixed spherical center, and the dynamic platform rotates spherically around the dynamic spherical center, and the distance between the two spherical centers is equal to the center distance between the tibiotalar joint and the subtalar joint of the ankle joint; the three metamorphic branches are respectively connected to the left and right sides and the front end of the static platform and the dynamic platform, and the No. 1 connecting rod of the metamorphic branch serves as an active part, so that the metamorphic branch can realize the transformation from S pair to U pair and R pair, so that the mechanism has different motion modes, and each metamorphic branch is an SPU branch or a UPU branch in each mode.

[0007] Furthermore, the 3R branch chain includes an arc-shaped 3R branch chain first link and an L-shaped 3R branch chain second link; the two ends of the 3R branch chain first link are respectively hinged to the rear side of the static platform to form a revolving pair A1 and A2, the middle part of the 3R branch chain first link is hinged to one end of the 3R branch chain second link to form a revolving pair A3, and the other end of the 3R branch chain second link is hinged to the rear side of the moving platform to form a revolving pair A4; the revolving axes of the revolving pairs A1, A2 and A4 intersect at point P, which is the fixed spherical center of the mechanism; the revolving axes of the revolving pairs A3 and A4 intersect at point Q, which is the moving spherical center of the mechanism.

[0008] Furthermore, the three metamorphic branches are the first metamorphic branch, the second metamorphic branch and the third metamorphic branch. The first metamorphic branch is located on the right side of the mechanism, the second metamorphic branch is located on the left side of the mechanism, and the third metamorphic branch is located at the front end of the mechanism. The structure of each metamorphic branch is the same and the connection method is the same. Among them, the first metamorphic branch includes the first metamorphic branch No. 1 connecting rod to the first metamorphic branch No. 7 connecting rod; the lower end of the first metamorphic branch No. 1 connecting rod is hinged to the right side of the static platform to form a revolving pair B1, the upper end of the first metamorphic branch No. 1 connecting rod is hinged to the lower end of the first metamorphic branch No. 2 connecting rod and the lower end of the first metamorphic branch No. 3 connecting rod to form a revolving pair B2, the lower end of the first metamorphic branch No. 3 connecting rod is also hinged to the right side of the static platform to form a revolving pair B3, and the first The upper end of the No. 2 connecting rod of the first varicell branch chain is hinged to the lower end of the No. 4 connecting rod of the first varicell branch chain to form a revolving pair B4, the upper end of the No. 4 connecting rod of the first varicell branch chain is slidingly connected to the lower end of the No. 5 connecting rod of the first varicell branch chain to form a moving pair P1, the upper end of the No. 5 connecting rod of the first varicell branch chain is hinged to the lower end of the No. 6 connecting rod of the first varicell branch chain to form a revolving pair B5, the upper end of the No. 6 connecting rod of the first varicell branch chain is hinged to the lower end of the No. 7 connecting rod of the first varicell branch chain to form a revolving pair B6, and the upper end of the No. 7 connecting rod of the first varicell branch chain and the right side of the moving platform form a revolving pair B7; the revolving axes of the revolving pairs B1, B2, B3 and B4 intersect with the direction of the moving pair P1 at one point, and the revolving axes of the revolving pairs B5, B6 and B7 intersect with the direction of the moving pair P1 at another point.

[0009] Furthermore, the lower ends of the first metamorphic branch chain connecting rod No. 1, the second metamorphic branch chain connecting rod No. 1 and the third metamorphic branch chain connecting rod No. 1 are respectively connected to a motor to form drive one, two and three respectively.

[0010] Furthermore, the mechanism can achieve seven motion modes; Mode 1: The main motion is single-degree-of-freedom motion in the dorsiflexion and plantar flexion directions of the foot, with small-angle motion in the internal and external rotation directions; in this mode, the first metamorphic branch is the SPU branch, and the second and third metamorphic branches are both UPU branches. The main drive is drive 1, and drives 2 and 3 perform accompanying motions;

[0011] Mode 2: The main movement is single-degree-of-freedom movement in the inversion and varus directions of the foot. In this mode, the first and third metamorphic branches are both UPU branches, the second metamorphic branch is an SPU branch, and the main drive is drive 2, with drives 1 and 3 performing accompanying movements.

[0012] Mode 3: The main movement is single-degree-of-freedom movement in the direction of internal and external rotation of the foot, with small-angle movement in dorsiflexion, plantar flexion, and internal and external valgus. In this mode, the first and second metamorphic branches are both UPU branches, and the third metamorphic branch is the SPU branch. The main drive is drive 3, and drives 1 and 2 perform accompanying movements.

[0013] Mode 4: The main movement is two-degree-of-freedom movement in the dorsiflexion and plantar flexion directions and inversion and varus, with small-angle movement in the internal and external rotation directions. In this mode, the first and second metamorphic branches are both SPU branches, and the third metamorphic branch is the UPU branch. The main drives are drive 1 and drive 2, and drive 3 performs accompanying movement.

[0014] Mode 5: The main movements are two-degree-of-freedom movements in the foot's dorsiflexion and plantar flexion directions, as well as internal and external rotation, with small-angle movements in the internal and external valgus directions. In this mode, the first metamorphic branch is the SPU branch, and the second and third metamorphic branches are both UPU branches. The main drives are drive 1 and drive 3, with drive 2 performing accompanying movements.

[0015] Mode 6: The main movement is two-degree-of-freedom movement in the directions of inversion and internal rotation of the foot, with small-angle movement in the directions of dorsiflexion and plantar flexion. In this mode, the first metamorphic branch is the UPU branch, and the second and third metamorphic branches are both SPU branches. The main drives are drive 1 and drive 2, and drive 3 performs accompanying movement.

[0016] Mode 7: The main movements are three degrees of freedom of the foot: dorsiflexion and plantar flexion, inversion and pronation, and internal and external rotation. In this mode, the three metamorphic branches are all SPU branches, and the three drives are all main drives.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The static platform and the dynamic platform are connected by three metamorphic branches. The metamorphic branches can realize the switching from S-pair to U-pair to adjust the position and posture of the dynamic platform, so that the mechanism has 7 motion modes to meet the training needs of different ankle injury types and different rehabilitation stages, and carry out targeted rehabilitation training; the switching of the motion pairs of the metamorphic branches is simple and convenient.

[0019] 2. The static platform and the dynamic platform are connected by 3R branch chains. All the hinge holes of the 3R branch chains form three axes that intersect perpendicularly. The double centers of the 3R branch chains are the fixed spherical center and the dynamic spherical center. The position of the fixed spherical center corresponds to the center of the patient's tibiotalar joint, and the position of the dynamic spherical center corresponds to the center of the patient's subtalar joint. Compared with the mechanism in the existing technology that simply equates the movement of the ankle joint to spherical motion, the "double-center" structure of the 3R branch chain ensures that the movement of the mechanism during rehabilitation is consistent with the movement of the patient's ankle joint, avoiding the generation of large human-computer interaction forces, so as to avoid secondary damage to the patient. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0021] Figure 2 It is a structural schematic diagram of the static platform of the present invention;

[0022] Figure 3 It is a structural schematic diagram of the dynamic platform of the present invention;

[0023] Figure 4 Schematic diagram of the 3R branched chain structure of the present invention;

[0024] Figure 5 Schematic diagram of the metamorphic branched chain structure of the present invention;

[0025] Explanation of reference numerals: 1, static platform; 2, dynamic platform; 3, 3R branch chain; 4, metamorphic branch chain; 5, fixed ball center; 6, dynamic ball center; 7, servo motor;

[0026] 101. Static platform hinge support No. 1; 102. Static platform hinge support No. 2; 103. Static platform hinge support No. 3; 104. Static platform hinge support No. 4; 105. Static platform hinge support No. 5; 106. Static platform hinge support No. 6; 107. Static platform hinge support No. 7; 108. Static platform hinge support No. 8; 109. Bottom plate; 110. Vertical support; 201. Moving platform hinge support No. 1; 202. Moving platform hinge support No. 2 ; 203, movable platform hinge support No. 3; 301, 3R branch chain first link; 302, 3R branch chain second link; 401, first varicellal branch chain link No. 1; 402, first varicellal branch chain link No. 2; 403, first varicellal branch chain link No. 3; 404, first varicellal branch chain link No. 4; 405, first varicellal branch chain link No. 5; 406, first varicellal branch chain link No. 6; 407, first varicellal branch chain link No. 7. DETAILED DESCRIPTION

[0027] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but the scope of protection of the present application is not limited thereto.

[0028] The present invention provides a reconfigurable ankle joint rehabilitation parallel mechanism (parallel mechanism for short), such as Figure 1 As shown, the mechanism includes a static platform 1, a dynamic platform 2, a 3R branch chain 3, a servo motor 7 and three metamorphic branch chains 4;

[0029] like Figure 2 As shown, the static platform 1 includes a base plate 109 and a vertical support 110 located at the rear side of the base plate 109. Eight hinge supports are provided on the static platform 1, namely, static platform No. 1 hinge support 101 and static platform No. 2 hinge support 102 located on both sides of the upper part of the vertical support 110, static platform No. 3 hinge support 103 and static platform No. 4 hinge support 104 located on the right side of the base plate 109, static platform No. 5 hinge support 105 and static platform No. 6 hinge support 106 located on the left side of the base plate 109, and static platform No. 7 hinge support 107 and static platform No. 8 hinge support 108 located on the front side of the base plate 109. The two hinge supports located on the same side of the base plate 109 are symmetrical about the corresponding symmetry planes of the base plate 109.

[0030] like Figure 3 As shown, a movable platform No. 1 hinge support 201 and a movable platform No. 2 hinge support 202 are respectively provided on the left and right sides of the middle of the movable platform 2, and a movable platform No. 3 hinge support 203 is provided at the front end of the left side of the movable platform 2.

[0031] like Figure 4 As shown, the 3R branch chain 3 includes an arc-shaped 3R branch chain first link 301 and an L-shaped 3R branch chain second link 302; one end of the 3R branch chain first link 301 is hinged to the static platform No. 1 hinge support 101 to form a rotation pair A1, and the other end is hinged to the static platform No. 2 hinge support 102 to form a rotation pair A2, the middle part of the 3R branch chain first link 301 is hinged to one end of the 3R branch chain second link 302 to form a rotation pair A3, and the other end of the 3R branch chain second link 302 is hinged to the rear side of the moving platform 2 to form a rotation pair A4.

[0032] like Figure 5 As shown, the three metamorphic branches 4 are respectively the first metamorphic branch, the second metamorphic branch and the third metamorphic branch, and the metamorphic branch 4 can realize the transformation from S pair to U pair and R pair; wherein, the first metamorphic branch includes the first metamorphic branch connecting rod 401, the first metamorphic branch connecting rod 402, the first metamorphic branch connecting rod 403, the first metamorphic branch connecting rod 404, the first metamorphic branch connecting rod 405, the first metamorphic branch connecting rod 406 and the first metamorphic branch connecting rod 407; the structures of the other two metamorphic branches are similar;

[0033] The lower end of the first variable cell branch chain No. 1 connecting rod 401 is hinged to the static platform No. 3 hinge support 103 to form a revolving pair B1, the upper end of the first variable cell branch chain No. 1 connecting rod 401 is hinged to the lower end of the first variable cell branch chain No. 2 connecting rod 402 and the lower end of the first variable cell branch chain No. 3 connecting rod 403 to form a revolving pair B2, the lower end of the first variable cell branch chain No. 3 connecting rod 403 is hinged to the static platform No. 4 hinge support 104 to form a revolving pair B3, the upper end of the first variable cell branch chain No. 2 connecting rod 402 is hinged to the lower end of the first variable cell branch chain No. 4 connecting rod 404 to form a The upper end of the first metamorphic branch chain No. 4 connecting rod 404 is slidably connected to the lower end of the first metamorphic branch chain No. 5 connecting rod 405 to form a moving pair P1. The upper end of the first metamorphic branch chain No. 5 connecting rod 405 is hinged to the lower end of the first metamorphic branch chain No. 6 connecting rod 406 to form a revolving pair B5. The upper end of the first metamorphic branch chain No. 6 connecting rod 406 is hinged to the lower end of the first metamorphic branch chain No. 7 connecting rod 407 to form a revolving pair B6. The upper end of the first metamorphic branch chain No. 7 connecting rod 407 and the movable platform No. 2 hinge support 202 form a revolving pair B7.

[0034] The lower end of the No. 1 connecting rod of the second metamorphic branch chain is hinged to the No. 5 hinge support 105 of the static platform to form a revolving pair C1, the upper end of the No. 1 connecting rod of the second metamorphic branch chain is hinged to the lower end of the No. 2 connecting rod of the second metamorphic branch chain and the upper end of the No. 3 connecting rod of the second metamorphic branch chain to form a revolving pair C2, the lower end of the No. 3 connecting rod of the second metamorphic branch chain is hinged to the No. 6 hinge support 106 of the static platform to form a revolving pair C3, the upper end of the No. 2 connecting rod of the second metamorphic branch chain is hinged to the lower end of the No. 4 connecting rod of the second metamorphic branch chain to form a revolving pair C1. The upper end of the second metamorphic branch chain No. 4 connecting rod is slidably connected to the lower end of the second metamorphic branch chain No. 5 connecting rod to form a moving pair P2. The upper end of the second metamorphic branch chain No. 5 connecting rod and the lower end of the second metamorphic branch chain No. 6 connecting rod are hinged to form a revolving pair C5. The upper end of the second metamorphic branch chain No. 6 connecting rod and the lower end of the second metamorphic branch chain No. 7 connecting rod are hinged to form a revolving pair C6. The upper end of the second metamorphic branch chain No. 7 connecting rod and the movable platform No. 1 hinge support 201 form a revolving pair C7.

[0035] The lower end of the No. 1 link of the third metamorphic branch chain is hinged to the No. 7 hinge support 107 of the static platform to form a revolving pair D1, the upper end of the No. 1 link of the third metamorphic branch chain is hinged to the lower end of the No. 2 link of the third metamorphic branch chain and the upper end of the No. 3 link of the third metamorphic branch chain to form a revolving pair D2, the lower end of the No. 3 link of the third metamorphic branch chain is hinged to the No. 8 hinge support 108 of the static platform to form a revolving pair D3, the upper end of the No. 2 link of the third metamorphic branch chain is hinged to the lower end of the No. 4 link of the third metamorphic branch chain to form a revolving pair D4, The upper end of the third metamorphic branch chain No. 4 connecting rod is slidably connected to the lower end of the third metamorphic branch chain No. 5 connecting rod to form a moving pair P3. The upper end of the third metamorphic branch chain No. 5 connecting rod and the lower end of the third metamorphic branch chain No. 6 connecting rod are hinged to form a revolving pair D6. The upper end of the third metamorphic branch chain No. 6 connecting rod and the lower end of the third metamorphic branch chain No. 7 connecting rod are hinged to form a revolving pair D7.

[0036] The rotation axes of the above-mentioned revolving pairs B1, B2, B3 and B4 intersect with the direction of the moving pair P1 at point B01, the rotation axes of the revolving pairs B5, B6 and B7 intersect with the direction of the moving pair P1 at point B02, the rotation axes of the revolving pairs C1, C2, C3 and C4 intersect with the direction of the moving pair P2 at point C01, the rotation axes of the revolving pairs C5, C6 and C7 intersect with the direction of the moving pair P2 at point C02, the rotation axes of the revolving pairs D1, D2, D3 and D4 intersect with the direction of the moving pair P3 at point D01, and the rotation axes of the revolving pairs C1, C2, C3 and C4 intersect with the direction of the moving pair P2 at point C01. The rotation axes of D5, D6 and D7 intersect with the direction of the moving pair P3 at point D02; the rotation axes of the rotation pairs A1, A2 and A4 intersect at point P, which is the fixed spherical center 5 of the parallel mechanism; the rotation axes of the rotation pairs A3 and A4 intersect at point Q, which is the moving spherical center 6 of the parallel mechanism, that is, the 3R branch chain 3 is a "double-center" structure, and the distance between the fixed spherical center 5 and the moving spherical center 6 is a fixed value, which is set according to the size of the patient's ankle joint; the moving spherical center 6 rotates spherically around the fixed spherical center 5, and the moving platform 2 rotates spherically around the moving spherical center 6.

[0037] Three servo motors 7 serve as the power source of the mechanism and are respectively installed on the static platform No. 3 hinge support 103, the static platform No. 5 hinge support 105 and the static platform No. 7 hinge support 107; the output shaft axis of the servo motor 7 installed at the static platform No. 3 hinge support 103 coincides with the rotation axis of the static platform No. 3 hinge support 103, and the output shaft of the servo motor 7 is fixedly connected to the lower end of the No. 1 connecting rod 401 of the first variable cell branch chain, forming drive one; the output shaft axis of the servo motor 7 installed at the static platform No. 5 hinge support 105 coincides with the rotation axis of the static platform No. 5 hinge support 105, and the output shaft of the servo motor 7 is fixedly connected to the lower end of the No. 1 connecting rod of the second variable cell branch chain, forming drive two; the output shaft axis of the servo motor 7 installed at the static platform No. 7 hinge support 107 coincides with the rotation axis of the static platform No. 7 hinge support 107, and the output shaft of the servo motor 7 is fixedly connected to the lower end of the No. 1 connecting rod of the third variable cell branch chain, forming drive three.

[0038] The working principle and workflow of the present invention are:

[0039] The movement of this parallel mechanism can be regarded as a combined movement of the spherical movement of the moving ball center 6 around the fixed ball center 5 and the spherical movement of the moving platform 2 around the moving ball center 6. The movement relationship between the fixed ball center 5 and the moving ball center 6 is completely determined by the three metamorphic branches 4. Drive one, drive two, and drive three control the movement of the mechanism by controlling the rotational movement of the first metamorphic branch chain No. 1, the second metamorphic branch chain No. 1, and the third metamorphic branch chain No. 1 relative to the bottom plate 109 of the static platform 1. The parallel mechanism controls the position and posture of the moving platform 2 by changing the configuration of the three metamorphic branches 4, thereby realizing seven foot movement modes to meet the training needs of different ankle injury types and different rehabilitation stages. The dual-center structure of the 3R branch chain 3 is used to fit the movement of the tibiotalar joint and the subtalar joint of the ankle joint, so as to reduce the human-computer interaction force generated during the ankle joint rehabilitation training; when this mechanism is actually used, the patient's foot is worn on the dynamic platform 2, the position of the fixed sphere center 5 corresponds to the center of the patient's tibiotalar joint, and the position of the dynamic sphere center 6 corresponds to the center of the patient's subtalar joint. The spherical movement of the dynamic sphere center 6 relative to the fixed sphere center 5 is used to fit the movement of the tibiotalar joint, thereby realizing the dorsiextension and plantar flexion movement of the foot; the spherical movement of the dynamic platform 2 relative to the dynamic sphere center 6 is used to fit the movement of the subtalar joint, thereby realizing the inversion and eversion movement and the internal and external rotation movement of the foot.

[0040] Mode 1: The main movement is single-degree-of-freedom movement in the dorsiflexion and plantar flexion directions of the foot, and small-angle movement in the directions of internal and external rotation; in this mode, the lower end of the sixth link of the first metamorphic branch chain and the middle part of the seventh link of the first metamorphic branch chain are fixedly connected, so that the sixth link of the first metamorphic branch chain and the seventh link of the first metamorphic branch chain become a whole; the middle part of the first link of the second metamorphic branch chain and the upper end of the second link of the second metamorphic branch chain are fixedly connected, so that the first link of the second metamorphic branch chain and the second link of the second metamorphic branch chain become a whole; the lower end of the sixth link of the second metamorphic branch chain and the middle part of the seventh link of the second metamorphic branch chain are fixedly connected, so that the sixth link of the second metamorphic branch chain and the seventh link of the second metamorphic branch chain become a whole The first and second varicell branches are connected as a whole; the middle of the third varicell branch link 1 is fixedly connected to the upper end of the third varicell branch link 2, forming a single unit. The lower end of the third varicell branch link 6 is fixedly connected to the middle of the third varicell branch link 7, forming a single unit. In this mode, the first varicell branch is the SPU branch, the second varicell branch is the UPU branch, and the third varicell branch is the UPU branch. Drive 1 is the primary driver, while drives 2 and 3 provide accompanying motion. The corresponding servo motors are de-energized and move in tandem with drive 1. This mode is suitable for early rehabilitation exercises for injuries to the ligaments and muscles associated with internal and external rotation, varus, and valgus, as well as mid-term rehabilitation exercises for injuries to the ligaments or muscles associated with dorsiflexion and plantar flexion.

[0041] Mode 2: The main movement is single-degree-of-freedom movement in the direction of foot inversion and inversion. In this mode, the lower end of the sixth link of the second metamorphic branch chain and the middle of the seventh link of the second metamorphic branch chain are fixedly connected, so that the sixth link of the second metamorphic branch chain and the seventh link of the second metamorphic branch chain become a whole; the middle of the first link of the third metamorphic branch chain and the upper end of the second link of the third metamorphic branch chain are fixedly connected, so that the first link of the third metamorphic branch chain and the second link of the third metamorphic branch chain become a whole; the lower end of the sixth link of the third metamorphic branch chain and the middle of the seventh link of the third metamorphic branch chain are fixedly connected, so that the sixth link of the third metamorphic branch chain and the seventh link of the third metamorphic branch chain become a whole. The first metamorphic branch is connected to the first link of the first metamorphic branch, link No. 7, forming a whole. The middle of the first metamorphic branch link No. 1 is fixedly connected to the upper end of the first metamorphic branch link No. 2, forming a whole with the first metamorphic branch link No. 1. The lower end of the first metamorphic branch link No. 6 is fixedly connected to the middle of the first metamorphic branch link No. 7, forming a whole with the first metamorphic branch link No. 6. In this mode, the first metamorphic branch is the UPU branch, the second metamorphic branch is the SPU branch, and the third metamorphic branch is the UPU branch. Drive 2 is the primary drive, with drives 1 and 3 performing accompanying movements. This mode is suitable for early rehabilitation exercises for ligament and muscle injuries associated with dorsiflexion and plantar flexion, as well as mid-term rehabilitation exercises for ligament and muscle injuries associated with varus and valgus.

[0042] Mode 3: The main movement is single-degree-of-freedom movement in the direction of internal and external rotation of the foot, and small-angle movement in the directions of dorsiflexion, plantar flexion and internal and external valgus; in this mode, the lower end of the sixth link of the third metamorphic branch chain is fixedly connected to the middle of the seventh link of the third metamorphic branch chain, so that the sixth link of the third metamorphic branch chain and the seventh link of the third metamorphic branch chain become a whole; the middle of the first link of the first metamorphic branch chain and the upper end of the second link of the first metamorphic branch chain are fixedly connected, so that the first link of the first metamorphic branch chain and the second link of the first metamorphic branch chain become a whole; the lower end of the sixth link of the first metamorphic branch chain and the middle of the seventh link of the first metamorphic branch chain are fixedly connected, so that the sixth link of the first metamorphic branch chain and the seventh link of the first metamorphic branch chain become a whole The connecting rod and connecting rod 7 of the first metamorphic branch chain form an integral whole. The middle of connecting rod 1 of the second metamorphic branch chain is fixedly connected to the upper end of connecting rod 2 of the second metamorphic branch chain, forming a single unit. The lower end of connecting rod 6 of the second metamorphic branch chain is fixedly connected to the middle of connecting rod 7 of the second metamorphic branch chain, forming a single unit. In this mode, the first metamorphic branch chain is the UPU branch, the second metamorphic branch chain is the UPU branch, and the third metamorphic branch chain is the SPU branch. Drive 3 is the primary driver, while drives 1 and 2 provide accompanying motion. This mode is suitable for early rehabilitation exercises for ligament and muscle injuries associated with dorsiflexion and plantar flexion, as well as mid-term rehabilitation exercises for ligament and muscle injuries associated with internal and external rotation.

[0043] Mode 4: The main movement is the two-degree-of-freedom movement of the foot in the directions of dorsiflexion and plantar flexion and internal and external rotation, and the internal and external rotation directions make a small angle movement; in this mode, the lower end of the sixth link of the first metamorphic branch chain is fixedly connected to the middle of the seventh link of the first metamorphic branch chain, so that the sixth link of the first metamorphic branch chain and the seventh link of the first metamorphic branch chain become a whole; the lower end of the sixth link of the second metamorphic branch chain is fixedly connected to the middle of the seventh link of the second metamorphic branch chain, so that the sixth link of the second metamorphic branch chain and the seventh link of the second metamorphic branch chain become a whole; the first link of the third metamorphic branch chain is fixedly connected to the middle of the seventh link of the second metamorphic branch chain The middle section is fixedly connected to the upper end of the second link of the third metamorphic branch, forming a single unit with the first and second links. The lower end of the sixth link of the third metamorphic branch is fixedly connected to the middle section of the seventh link, forming a single unit with the sixth and seventh links. In this mode, the first metamorphic branch functions as the SPU, the second as the SPU, and the third as the UPU. Drives 1 and 2 are the primary drivers, with drive 3 providing accompanying motion. This mode is suitable for late-stage rehabilitation exercises for injured ligaments and muscles associated with dorsiflexion, plantar flexion, and internal and external valgus.

[0044] Mode 5: The main movement is the two-degree-of-freedom movement of the foot in the directions of dorsiflexion and plantar flexion and internal and external rotation, and a small angle movement in the directions of internal and external valgus; in this mode, the lower end of the sixth link of the first metamorphic branch chain is fixedly connected to the middle of the seventh link of the first metamorphic branch chain, so that the sixth link of the first metamorphic branch chain and the seventh link of the first metamorphic branch chain become a whole; the lower end of the sixth link of the third metamorphic branch chain is fixedly connected to the middle of the seventh link of the third metamorphic branch chain, so that the sixth link of the third metamorphic branch chain and the seventh link of the third metamorphic branch chain become a whole; the first link of the second metamorphic branch chain is fixedly connected to the middle of the seventh link of the third metamorphic branch chain, so that the sixth link of the third metamorphic branch chain and the seventh link of the third metamorphic branch chain become a whole; The middle section is fixedly connected to the upper end of the second metamorphic branch's connecting rod, link 2, forming a single unit. The lower end of the second metamorphic branch's connecting rod, link 6, and link 7 are fixedly connected to the middle section of the second metamorphic branch's connecting rod, forming a single unit. In this mode, the first metamorphic branch functions as the SPU, the second as the UPU, and the third as the SPU. Drives 1 and 3 are the primary drivers, with drive 2 providing accompanying motion. This mode is suitable for late-stage rehabilitation exercises for injured ligaments and muscles associated with dorsiflexion, plantar flexion, and internal and external rotation.

[0045] Mode 6: The main movement is the two-degree-of-freedom movement of the foot in the directions of inversion and internal and external rotation, and the dorsiflexion and plantar flexion directions make a small angle movement; in this mode, the lower end of the sixth link of the second metamorphic branch chain and the middle of the seventh link of the second metamorphic branch chain are fixedly connected, so that the sixth link of the second metamorphic branch chain and the seventh link of the first metamorphic branch chain become a whole; the lower end of the sixth link of the third metamorphic branch chain and the middle of the seventh link of the third metamorphic branch chain are fixedly connected, so that the sixth link of the third metamorphic branch chain and the seventh link of the second metamorphic branch chain become a whole; the first link of the first metamorphic branch chain The middle section is fixedly connected to the upper end of the first metamorphic branch link #2, forming a single unit. The lower end of the first metamorphic branch link #6 is fixedly connected to the middle section of the first metamorphic branch link #7, forming a single unit. In this mode, the first metamorphic branch acts as the UPU, the second metamorphic branch acts as the SPU, and the third metamorphic branch acts as the SPU. Drives 2 and 3 are the primary drivers, with drive 1 providing accompanying motion. This mode is suitable for mid-term rehabilitation of damaged ligaments and muscles associated with internal and external rotation and internal and external varus.

[0046] Mode seven: The main movement is three-degree-of-freedom movement of the foot in the directions of dorsiextension and plantar flexion, internal and external rotation, and internal and external rotation; in this mode, the lower end of the sixth link of the first metamorphic branch chain and the middle part of the seventh link of the first metamorphic branch chain are fixedly connected, so that the sixth link of the first metamorphic branch chain and the seventh link of the first metamorphic branch chain become a whole; the lower end of the sixth link of the second metamorphic branch chain and the middle part of the seventh link of the third metamorphic branch chain are fixedly connected, so that the sixth link of the second metamorphic branch chain and the seventh link of the second metamorphic branch chain become a whole; the lower end of the sixth link of the third metamorphic branch chain and the middle part of the seventh link of the third metamorphic branch chain are fixedly connected, so that the sixth link of the third metamorphic branch chain and the seventh link of the third metamorphic branch chain become a whole; in this mode, the first metamorphic branch chain is an SPU branch, the second metamorphic branch chain is an SPU branch, and the third metamorphic branch chain is an SPU branch, and the main drives are drive one, drive two, and drive three. This model is suitable for late rehabilitation exercises for injuries to the ligaments and muscles associated with dorsiextension, plantar flexion, internal and external rotation.

[0047] In the above-mentioned SPU branch chain and UPU branch chain, "S" represents a spherical joint with three degrees of freedom, "P" represents a translation joint with one, and "U" represents two rotation joints.

[0048] Any matters not described in the present invention are applicable to the prior art.

Claims

1. A reconfigurable ankle joint rehabilitation parallel mechanism, comprising a static platform and a dynamic platform; characterized in that: The mechanism also includes a 3R branch chain and three metamorphic branch chains; the rear ends of the static platform and the dynamic platform are connected by the 3R branch chain, so that the mechanism has a fixed spherical center and a dynamic spherical center. The dynamic spherical center rotates spherically around the fixed spherical center, and the dynamic platform rotates spherically around the dynamic spherical center. The distance between the two spherical centers is equal to the center distance between the tibiotalar joint and the subtalar joint of the ankle joint; the first, second and third metamorphic branch chains are respectively connected to the right and left sides and the front end of the static platform and the dynamic platform. The No. 1 connecting rod of the metamorphic branch chain serves as an active component, so that the metamorphic branch chain can realize the transformation from the S pair to the U pair and the R pair, so that the mechanism has seven different motion modes. In each mode, each metamorphic branch chain is an SPU branch chain or a UPU branch chain. The lower ends of the first metamorphic branch link No. 1, the second metamorphic branch link No. 1, and the third metamorphic branch link No. 1 are respectively connected to a motor at the hinged position with the static platform to form drive one, two, and three respectively; Mode 1: The main movement is single-degree-of-freedom movement in the dorsiflexion and plantar flexion directions of the foot, with small-angle movement in the internal and external rotation directions. In this mode, the first metamorphic branch is the SPU branch, and the second and third metamorphic branches are both UPU branches. The main drive is drive 1, and drives 2 and 3 perform accompanying movements. Mode 2: The main movement is single-degree-of-freedom movement in the inversion and varus directions of the foot. In this mode, the first and third metamorphic branches are both UPU branches, the second metamorphic branch is an SPU branch, and the main drive is drive 2, with drives 1 and 3 performing accompanying movements. Mode 3: The main movement is single-degree-of-freedom movement in the direction of internal and external rotation of the foot, with small-angle movement in dorsiflexion, plantar flexion, and internal and external valgus. In this mode, the first and second metamorphic branches are both UPU branches, and the third metamorphic branch is the SPU branch. The main drive is drive 3, and drives 1 and 2 perform accompanying movements. Mode 4: The main movement is two-degree-of-freedom movement in the dorsiflexion and plantar flexion directions and inversion and varus, with small-angle movement in the internal and external rotation directions. In this mode, the first and second metamorphic branches are both SPU branches, and the third metamorphic branch is the UPU branch. The main drives are drive 1 and drive 2, and drive 3 performs accompanying movement. Mode 5: The main movements are two-degree-of-freedom movements in the foot's dorsiflexion and plantar flexion directions, as well as internal and external rotation, with small-angle movements in the internal and external valgus directions. In this mode, the first metamorphic branch is the SPU branch, and the second and third metamorphic branches are both UPU branches. The main drives are drive 1 and drive 3, with drive 2 performing accompanying movements. Mode 6: The main movement is two-degree-of-freedom movement in the directions of inversion and internal rotation of the foot, with small-angle movement in dorsiflexion and plantar flexion. In this mode, the first metamorphic branch is the UPU branch, and the second and third metamorphic branches are both SPU branches. The main drives are drive 2 and drive 3, and drive 1 performs accompanying movement. Mode 7: The main movements are three degrees of freedom of the foot: dorsiflexion and plantar flexion, inversion and pronation, and internal and external rotation. In this mode, the three metamorphic branches are all SPU branches, and the three drives are all main drives.

2. The reconfigurable ankle joint rehabilitation parallel mechanism according to claim 1, characterized in that: The 3R branch chain includes an arc-shaped 3R branch chain first link and an L-shaped 3R branch chain second link; the two ends of the 3R branch chain first link are respectively hinged to the rear side of the static platform to form a revolving pair A1 and A2, the middle part of the 3R branch chain first link is hinged to one end of the 3R branch chain second link to form a revolving pair A3, and the other end of the 3R branch chain second link is hinged to the rear side of the moving platform to form a revolving pair A4; the revolving axes of the revolving pairs A1, A2 and A4 intersect at point P, which is the fixed spherical center of the mechanism; the revolving axes of the revolving pairs A3 and A4 intersect at point Q, which is the moving spherical center of the mechanism.

3. The reconfigurable ankle joint rehabilitation parallel mechanism according to claim 1 or 2, characterized in that: The structure of each metamorphic branch chain is the same, and the connection method is the same; among them, the first metamorphic branch chain includes the first metamorphic branch chain connecting rod No. 1 to the first metamorphic branch chain connecting rod No. 7; the lower end of the first metamorphic branch chain connecting rod No. 1 is hinged to the right side of the static platform to form a revolving pair B1, the upper end of the first metamorphic branch chain connecting rod No. 1 is hinged to the lower end of the first metamorphic branch chain connecting rod No. 2 and the lower end of the first metamorphic branch chain connecting rod No. 3 to form a revolving pair B2, the lower end of the first metamorphic branch chain connecting rod No. 3 is also hinged to the right side of the static platform to form a revolving pair B3, the upper end of the first metamorphic branch chain connecting rod No. 2 is hinged to the lower end of the first metamorphic branch chain connecting rod No. 4 to form a revolving pair B4, and the first The upper end of the fourth connecting rod of the metamorphic branch chain is slidingly connected to the lower end of the fifth connecting rod of the first metamorphic branch chain to form a moving pair P1, the upper end of the fifth connecting rod of the first metamorphic branch chain is hinged to the lower end of the sixth connecting rod of the first metamorphic branch chain to form a rotary pair B5, the upper end of the sixth connecting rod of the first metamorphic branch chain is hinged to the lower end of the seventh connecting rod of the first metamorphic branch chain to form a rotary pair B6, and the upper end of the seventh connecting rod of the first metamorphic branch chain and the right side of the moving platform form a rotary pair B7; the rotary axes of the rotary pairs B1, B2, B3 and B4 intersect with the direction of the moving pair P1 at one point, and the rotary axes of the rotary pairs B5, B6 and B7 intersect with the direction of the moving pair P1 at another point.

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