Ankle joint parallel rehabilitation mechanism

Abstract

The invention relates to an ankle joint parallel rehabilitation mechanism, which belongs to the technical field of medical rehabilitation instruments and comprises a static platform, a movable platform, a mechanism frame, three RPS branched chains, an SPS branched chain and an RPRR accompanying branched chain. The three RPS accompanying branch chains are distributed in a triangular shape around the center SPS branch chain and connected between the static platform and the movable platform. The RPRR branch chains are connected with the frame and the movable platform. And the movable platform is driven to realize multi-degree-of-freedom movement of three-rotation and one-movement through cooperative extension and retraction of the branched chains. The RPRR branch chains adjust the height of the rotating center through the moving pairs so that the rotating center can coincide with the physiological center of the ankle joint of the human body. The device is compact in structure, stable in movement and capable of meeting the ankle joint core rehabilitation requirement, effectively solves the problem that man-machine movement centers are not matched, and avoids secondary injury in training.

Description

Technical Field

[0001] This invention relates to the field of medical rehabilitation equipment technology, and in particular to a parallel ankle joint rehabilitation mechanism. Background Technology

[0002] The ankle joint is one of the most important weight-bearing joints in the human musculoskeletal system, playing a crucial role in weight-bearing and balance regulation during daily activities such as standing, walking, running, and jumping. Due to its complex anatomical structure and heavy load-bearing capacity, the ankle joint is also one of the joints with the highest incidence of sports injuries. If ankle injuries are not treated with timely and scientific rehabilitation training, they can easily lead to joint stiffness, muscle atrophy, and even permanent motor dysfunction, severely impacting the patient's quality of life.

[0003] Traditional ankle rehabilitation primarily relies on one-on-one manual therapy by physical therapists. This approach is extremely physically demanding for therapists, making it difficult to guarantee prolonged, highly repetitive training intensity and consistent movements. Furthermore, the scarcity of professional physical therapists leads to high treatment costs, leaving many patients unable to access adequate rehabilitation services. In addition, manual therapy relies heavily on the therapist's personal experience, lacking quantifiable data feedback and hindering accurate assessment of rehabilitation progress.

[0004] To compensate for the shortcomings of manual rehabilitation, rehabilitation equipment based on robotics technology has gradually become a research hotspot. Current ankle rehabilitation robots are mainly divided into two categories: serial mechanisms and parallel mechanisms. Serial mechanisms are typically bulky, have high moment of inertia, and suffer from poor compliance and safety due to the direct load-bearing capacity of the joint drive motors. In contrast, parallel mechanisms offer advantages such as high stiffness, strong load-bearing capacity, and low cumulative error, making them more suitable for ankle rehabilitation applications requiring high load-bearing capacity and precise control.

[0005] However, existing ankle joint rehabilitation devices still face many challenges in practical application. For example, traditional Stewart platforms or simple 3-RPS mechanisms often struggle to address the issue of matching the center of rotation. The movement of the human ankle joint is not a simple fixed-axis rotation; its physiological center of rotation changes dynamically during movement, and different patients have different ankle joint sizes. If existing devices lack effective mechanisms for adjusting and constraining the center of rotation, their mechanical center of rotation cannot coincide with the patient's physiological center of rotation. This "human-machine mismatch" can generate unexpected shear or compressive forces on the ankle joint during training, easily causing secondary damage to the articular cartilage or ligaments.

[0006] Furthermore, existing simplified parallel mechanisms often struggle to achieve a balance between movement dimensions and stability. While some mechanisms are structurally simple, they lack sufficient degrees of freedom to fully cover the ankle's required dorsiflexion / plantar flexion, inversion / eversion, adduction / abduction, and axial stretching movements, resulting in limited rehabilitation outcomes. Simultaneously, some low-degree-of-freedom mechanisms, lacking dedicated accompanying branch constraints, are prone to unusual positioning or jerking during movement, affecting the stability and safety of rehabilitation training. Therefore, developing a compact ankle parallel rehabilitation mechanism capable of enabling multi-degree-of-freedom compound movements and effectively adjusting the rotation center to prevent secondary injuries is a pressing technical challenge. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a parallel ankle joint rehabilitation mechanism. This mechanism uses the coordinated extension and retraction of three RPS branches and the central SPS branch to drive a multi-degree-of-freedom compound rehabilitation exercise platform. It utilizes the RPRR accompanying branch to constrain the movement trajectory and adjust the height of the rotation center to adapt to the physiological structure of the human ankle joint, thereby solving the problem of human-machine motion center mismatch in existing mechanisms and achieving safe, accurate rehabilitation training that avoids secondary injuries.

[0008] To achieve the above objectives, the present invention provides a parallel ankle rehabilitation mechanism, comprising: a static platform, a mechanism frame, a dynamic platform, three RPS branches, one SPS branch, and one RPRR accompanying branch;

[0009] The mechanism frame is fixedly mounted on one side of the static platform and extends upward; the moving platform is located above the static platform.

[0010] The three RPS branches and the one SPS branch are all connected between the static platform and the dynamic platform, and the three RPS branches are distributed around the SPS branch.

[0011] One end of the RPRR accompanying branch is connected to the mechanism frame, and the other end is connected to the moving platform;

[0012] The moving platform performs multi-degree-of-freedom motion relative to the static platform through the three RPS branches, the one SPS branch, and the RPRR accompanying branch.

[0013] Furthermore, the three RPS branches have the same structure, and each RPS branch includes a first revolute joint, a first prismatic joint, and a first ball joint;

[0014] The first rotating joint is mounted on the stationary platform, one end of the first sliding joint is connected to the first rotating joint, the other end of the first sliding joint is connected to one end of the first ball joint, and the other end of the first ball joint is connected to the moving platform.

[0015] Furthermore, the first movable pair includes a first hydraulic cylinder or a first electric push rod, and the first movable pair is capable of telescopic movement along its axial direction to change the distance between the static platform and the moving platform.

[0016] Furthermore, the SPS branch is located at the center of the static platform, and the SPS branch includes a second ball joint, a second sliding joint, and a third ball joint;

[0017] The second ball joint is mounted on the stationary platform, the bottom end of the second movable joint is connected to the second ball joint, the top end of the second movable joint is connected to the third ball joint, and the third ball joint is connected to the center position of the moving platform.

[0018] Furthermore, the accompanying branch of the RPRR includes a second revolute joint, a third prismatic joint, a third revolute joint, and a fourth revolute joint;

[0019] The second revolute joint is connected to one of the suspended ends of the mechanism frame. The third prismatic joint is connected to the mechanism frame through the second revolute joint. The third revolute joint is connected to the third prismatic joint. The fourth revolute joint is connected between the third revolute joint and the moving platform.

[0020] Furthermore, the third prismatic joint is arranged vertically and is configured to adjust the rotation center height of the rehabilitation mechanism; the rotation axes of the second, third, and fourth prismatic joints are used to constrain the motion trajectory of the moving platform.

[0021] Furthermore, the mechanism frame includes a vertical support rod and a horizontal cantilever rod. The bottom end of the vertical support rod is fixedly connected to the static platform, and the horizontal cantilever rod is connected to the top end of the vertical support rod. The horizontal cantilever rod extends above the moving platform, and the RPRR is connected to the end of the horizontal cantilever rod via an accompanying branch.

[0022] Furthermore, the three RPS branches are RPS branch I, RPS branch II, and RPS branch III, respectively.

[0023] The RPS branch I, RPS branch II, and RPS branch III are arranged in an equilateral triangle on the static platform, with the SPS branch located on the central geometric perpendicular line of the equilateral triangle.

[0024] Furthermore, the static platform is a circular base, and the static platform is provided with mounting holes for installing the three RPS branches and the one SPS branch; the moving platform is a circular pedal.

[0025] Furthermore, the upper surface of the moving platform is provided with a fixing component for fixing the user's feet, the fixing component including a flexible pad and a fastening strap disposed on the flexible pad.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) This invention adopts a parallel mechanism configuration consisting of three RPS branches, one SPS central branch, and one RPRR accompanying branch. Through the coordinated movement of each branch, the moving platform can achieve four degrees of freedom of movement (three rotations and one transfer) relative to the static platform. This specific structural configuration enables the rehabilitation mechanism to not only accurately achieve the three core rotational trainings required for ankle joint rehabilitation (dorsiflexion / plantar flexion, inversion / eversion, and adduction / abduction), but also to achieve passive stretching (transfer) training along the lower leg axis. Compared with traditional simplified mechanisms with insufficient degrees of freedom, this invention can cover the full range of rehabilitation exercise needs of the ankle joint, and the parallel structure has the advantages of strong load-bearing capacity and small cumulative error, ensuring the accuracy of rehabilitation movements.

[0028] (2) This invention effectively solves the problem of human-machine motion center matching by setting up an RPRR accompanying branch connecting the mechanism frame and the moving platform, especially by utilizing its included vertical sliding joint. The RPRR accompanying branch not only constrains the motion trajectory of the moving platform, but more importantly, its sliding joint can flexibly adjust the height of the mechanism's rotation center according to different patients' foot sizes and ankle joint physiological structures, ensuring that the mechanical rotation center of the mechanism always coincides with the physiological rotation center of the patient's ankle joint (i.e., human-machine integration). This method eliminates the unexpected shear or compressive forces generated during training due to misalignment of rotation centers, effectively avoiding "secondary damage" to the patient's damaged joints, and significantly improving the safety and comfort of rehabilitation training.

[0029] (3) In this invention, an SPS branch is set at the center of the three drive branches, which connects the center of the static platform and the center of the moving platform through a combination of ball joints and sliding joints. The SPS branch plays a key role in central support and stiffness enhancement in the mechanism. It can effectively share the weight of the moving platform and the patient's limb, prevent the moving platform from tilting or shaking during movement, and significantly improve the overall structural stiffness and load stability of the mechanism. At the same time, as a central constraint rod, the SPS branch helps to avoid singular configurations of the mechanism in the workspace, ensuring that the mechanism remains stable and smooth when performing complex compound movements.

[0030] (4) In this invention, three identical RPS drive chains are symmetrically distributed in an equilateral triangle on a static platform and arranged around the central SPS chain. This highly symmetrical layout gives the mechanism good kinematic isotropy and more uniform force distribution, greatly simplifying the kinematic forward and inverse kinematics algorithms and control strategies, and reducing the development difficulty and manufacturing cost of the system. At the same time, the RPS chain adopts a series connection of revolute joint-prioritized joint-spherical joint, which is simple and compact. The moving platform can be flexibly driven to complete various complex spatial rehabilitation trajectories through the differentiated extension and retraction of the three chains, which has the advantages of simple structure, fast response speed and high operational reliability. Attached Figure Description

[0031] Figure 1 This is an axonometric schematic diagram of the overall structure of a parallel ankle joint rehabilitation mechanism according to the present invention.

[0032] Labeling explanations: 1. Mechanism frame; 2. RPRR accompanying branch; 3. RPS branch II; 4. RPS branch III; 5. Static platform; 6. SPS branch; 7. RPS branch I; 8. Dynamic platform. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0034] In the description of this invention, it should be understood that the terms "center," "axial," "lateral," "upper," "lower," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0035] In the description of the invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0036] like Figure 1 As shown, this embodiment of the invention provides a parallel ankle rehabilitation mechanism, including: a static platform 5, a mechanism frame 1, a moving platform 8, three RPS branches, one SPS branch 6, and one RPRR accompanying branch 2; the mechanism frame 1 is fixedly disposed on one side of the static platform 5 and extends upward; the moving platform 8 is disposed above the static platform 5; the three RPS branches and the one SPS branch 6 are all connected between the static platform 5 and the moving platform 8, and the three RPS branches are distributed around the SPS branch 6; one end of the RPRR accompanying branch 2 is connected to the mechanism frame 1, and the other end is connected to the moving platform 8; the moving platform 8 performs multi-degree-of-freedom movements relative to the static platform 5 through the three RPS branches, the one SPS branch 6, and the RPRR accompanying branch 2.

[0037] The three RPS branches have identical structures. Each RPS branch includes a first revolute joint, a first prismatic joint, and a first ball joint. The first revolute joint is mounted on the stationary platform 5. One end of the first prismatic joint is connected to the first revolute joint, and the other end of the first prismatic joint is connected to one end of the first ball joint. The other end of the first ball joint is connected to the moving platform 8. The first prismatic joint includes a first hydraulic cylinder or a first electric push rod. The first prismatic joint can extend and retract along its axial direction to change the distance between the stationary platform 5 and the moving platform 8.

[0038] SPS branch 6 is located at the center of the stationary platform 5. SPS branch 6 includes a second ball joint, a second sliding joint and a third ball joint. The second ball joint is installed on the stationary platform 5. The bottom end of the second sliding joint is connected to the second ball joint. The top end of the second sliding joint is connected to the third ball joint. The third ball joint is connected to the center of the moving platform 8.

[0039] The RPRR accompanying branch 2 includes a second revolute joint, a third prismatic joint, a third revolute joint, and a fourth revolute joint. The second revolute joint is connected to one suspended end of the mechanism frame 1. The third prismatic joint is connected to the mechanism frame 1 via the second revolute joint and is also connected to the third prismatic joint. The fourth revolute joint is connected between the third revolute joint and the moving platform 8. The third prismatic joint is arranged vertically and is configured to adjust the height of the rotation center of the rehabilitation mechanism. The rotation axes of the second, third, and fourth revolute joints are used to constrain the motion trajectory of the moving platform 8.

[0040] The mechanism frame 1 includes a vertical support rod and a horizontal cantilever rod. The bottom end of the vertical support rod is fixedly connected to the static platform 5, and the horizontal cantilever rod is connected to the top end of the vertical support rod, extending above the moving platform 8. The RPRR (Receiving Power Response) branch 2 is connected to the end of the horizontal cantilever rod. Three RPS branches are designated as RPS branch I 7, RPS branch II 3, and RPS branch III 4; these branches are arranged in an equilateral triangle on the static platform 5, with the SPS branch 6 located on the central geometrical perpendicular line of the equilateral triangle. The static platform 5 is a circular base with mounting holes for the three RPS branches and one SPS branch 6. The moving platform 8 is a circular footrest. The upper surface of the moving platform 8 has a fixing component for securing the user's feet, including a flexible pad and fastening straps on the flexible pad.

[0041] This rehabilitation facility uses a static platform 5 as a fixed base, and a flexible pad and fastening straps on a dynamic platform 8 to stabilize the patient's foot. It utilizes the coordinated movements of three RPS branches and SPS branches 6 to precisely achieve core rehabilitation movements such as ankle dorsiflexion, plantar flexion, inversion / eversion, adduction / abduction. Simultaneously, the RPRR (Repetitive Stretch Reduction) mechanism, along with the moving joint of branch 2, can perform passive stretching training of the damaged ankle joint and adjust the height of the mechanism's rotation center to coincide with the physiological rotation center of the human ankle joint, thus avoiding secondary injury. The control device flexibly adjusts the branch extension and contraction, movement rate, and rehabilitation angle according to the patient's ankle joint size and rehabilitation stage. The measuring device records real-time biomechanical data such as the movement parameters of the dynamic platform 8 and the amount of ankle muscle activity, providing a basis for rehabilitation assessment. This facility has a simple structure, is easy to operate, covers the rehabilitation needs of the ankle joint's three rotations and one transfer, has no gaps or singularities in the workspace, ensures stable and safe movement, significantly improves the rehabilitation effect of damaged ankle joints, and is suitable for long-term rehabilitation training.

[0042] For the three rotational movements of the ankle core, dorsiflexion is accomplished by the opposing extension and contraction of RPS branch I 7, RPS branch II 3, and RPS branch III 4. During dorsiflexion, RPS branch I 7 extends, while RPS branch II 3 and RPS branch III 4 shorten, and vice versa during plantarflexion. Inversion and eversion movements depend on the opposing extension and contraction of RPS branch I 7, RPS branch III 4, and RPS branch II 3. During inversion, RPS branch II 3 shortens, while RPS branch I 7 and RPS branch III 4 extend, and vice versa during eversion. Adduction and abduction movements are achieved through the difference in the unilateral extension and contraction speed of the branches. During adduction, RPS branch I 7 and RPS branch II 3 extend to the right, with RPS branch II 3 extending faster. During abduction, RPS branch II 3 and RPS branch III 4 extend to the left, with RPS branch I 7 extending faster. In addition, the RPRR, along with the locomotor joint of branch 2, can extend and retract along the Z-axis, providing passive stretching training for the ankle joint.

[0043] This institution utilizes motion adaptation and human-machine integration to assist rehabilitation. Its exercises fully cover the ankle joint's needs for dorsiflexion, plantar flexion, inversion / eversion, adduction / abduction, and passive stretching, specifically activating the muscles surrounding the damaged ankle joint. Simultaneously, the institution's rotation center coincides with the ankle joint's physiological rotation center, preventing uneven stress on the joint during rehabilitation and avoiding secondary injuries. The motion platform 8 is made of flexible materials and is sized to fit most adult foot types, enhancing rehabilitation comfort. The passive stretching function improves blood circulation in the soft tissues around the ankle joint. Combined with the three rotational movements, it helps the damaged ankle joint regain range of motion, strengthens muscles, and achieves effective rehabilitation training.

[0044] When the drive motor drives the locating joints to extend and retract, the locating joints of the three RPS chains, through differentiated extension and retraction, cooperate with the ball joints and revolute joints to drive the moving platform 8. The movement patterns can achieve single-degree-of-freedom and multi-degree-of-freedom compound movements according to rehabilitation needs: when a single locating joint is driven alone, the moving platform 8 can achieve unidirectional reciprocating rotation such as dorsiflexion and plantarflexion; when two locating joints are driven in tandem, they can achieve fixed-axis reciprocating compound rotation such as inversion accompanied by dorsiflexion, with the coronal axis and sagittal axis at fixed angles; when all three locating joints move simultaneously, the footrest can achieve three-degree-of-freedom compound rehabilitation movements of dorsiflexion and plantarflexion, inversion and eversion, and adduction and abduction. At the same time, the RPRR accompanying chain 2 constrains the direction of movement through the revolute joint, and at the same time, with the help of the locating joint adjustment mechanism, it makes its rotation center coincide with the rotation center of the human ankle joint, achieving human-machine integration and avoiding secondary injury during rehabilitation.

[0045] The experimental setup consists of two parts: a fixed component and a moving component. The fixed component comprises a static platform 5 and a mechanism frame 1. The static platform 5 is placed on the ground, and the mechanism frame 1 is installed together with the static platform 5. The moving component consists of three identical RPS branches (RPS branch II 3, RPS branch III 4, and RPS branch I 7), an SPS branch 6, an RPRR accompanying branch 2, and a moving platform 8. The RPRR accompanying branch 2 is assembled with the mechanism frame 1 to form a stable structure. The moving platform 8 is equipped with pedals and straps for securing the ankles.

[0046] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0047] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An ankle parallel rehabilitation mechanism, characterized in that, The rehabilitation mechanism comprises a static platform (5), a mechanism frame (1), a dynamic platform (8), three RPS branch chains, one SPS branch chain (6), and one RPRR accompanying branch chain (2). The mechanism frame (1) is fixedly arranged on one side of the static platform (5) and extends upward; the dynamic platform (8) is arranged above the static platform (5). The three RPS branch chains and the one SPS branch chain (6) are connected between the static platform (5) and the dynamic platform (8), and the three RPS branch chains are distributed around the SPS branch chain (6). One end of the RPRR accompanying branch chain (2) is connected to the mechanism frame (1), and the other end is connected to the dynamic platform (8). The dynamic platform (8) moves relative to the static platform (5) in multiple degrees of freedom through the three RPS branch chains, the one SPS branch chain (6), and the RPRR accompanying branch chain (2). The three RPS branch chains are structurally identical, and each RPS branch chain comprises a first revolute pair, a first prismatic pair, and a first spherical pair.

2. The parallel mechanism for ankle rehabilitation according to claim 1, wherein The first revolute pair is mounted on the static platform (5), one end of the first prismatic pair is connected to the first revolute pair, the other end of the first prismatic pair is connected to one end of the first spherical pair, and the other end of the first spherical pair is connected to the dynamic platform (8). The first prismatic pair comprises a first hydraulic cylinder or a first electric push rod, and the first prismatic pair can move in the axial direction to change the distance between the static platform (5) and the dynamic platform (8).

3. The parallel mechanism for ankle rehabilitation according to claim 2, wherein The SPS branch chain (6) is arranged at the center of the static platform (5), and the SPS branch chain (6) comprises a second spherical pair, a second prismatic pair, and a third spherical pair.

4. The parallel mechanism for ankle rehabilitation according to claim 1, wherein The second spherical pair is mounted on the static platform (5), the bottom end of the second prismatic pair is connected to the second spherical pair, the top end of the second prismatic pair is connected to the third spherical pair, and the third spherical pair is connected to the center of the dynamic platform (8). The RPRR accompanying branch chain (2) comprises a second revolute pair, a third prismatic pair, a third revolute pair, and a fourth revolute pair.

5. The parallel mechanism for ankle rehabilitation according to claim 1, wherein The second revolute pair is connected to the free end of the mechanism frame (1), the third prismatic pair is connected to the mechanism frame (1) through the second revolute pair, the third revolute pair is connected to the third prismatic pair, and the fourth revolute pair is connected between the third revolute pair and the dynamic platform (8). The third prismatic pair is arranged in the vertical direction and is configured to adjust the height of the rotation center of the rehabilitation mechanism; the rotation axes of the second revolute pair, the third revolute pair, and the fourth revolute pair are used to constrain the motion trajectory of the dynamic platform (8).

6. The parallel mechanism for ankle rehabilitation according to claim 5, wherein, The mechanism frame (1) comprises a vertical support rod and a horizontal cantilever rod, the bottom end of the vertical support rod is fixedly connected to the static platform (5), the horizontal cantilever rod is connected to the top end of the vertical support rod, the horizontal cantilever rod extends above the dynamic platform (8), and the RPRR accompanying branch chain (2) is connected to the end of the horizontal cantilever rod.

7. The parallel mechanism for ankle rehabilitation according to claim 1, wherein ​ 8. The parallel mechanism for ankle rehabilitation according to claim 1, wherein The three RPS branches are RPS branch I (7), RPS branch II (3) and RPS branch III (4) respectively; The RPS branch I (7), the RPS branch II (3) and the RPS branch III (4) are distributed in an equilateral triangle on the static platform (5), and the SPS branch (6) is located on the central geometric vertical line of the equilateral triangle.

9. The parallel mechanism for ankle rehabilitation according to claim 1, wherein, The static platform (5) is a circular base, and the static platform (5) is provided with mounting hole positions for mounting the three RPS branches and the SPS branch (6); the dynamic platform (8) is a circular pedal.

10. The parallel mechanism for ankle rehabilitation according to claim 1, wherein, The upper surface of the dynamic platform (8) is provided with a fixing assembly for fixing the feet of a user, and the fixing assembly comprises a flexible pad layer and a fastening belt arranged on the flexible pad layer.

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