A rope-driven ankle rehabilitation robot

Abstract

The present application provides a kind of rope drive ankle rehabilitation robot, man-machine structure matching degree is higher, compliance safety is better, man-machine interaction is better, it is beneficial to promote ankle rehabilitation training effect and efficiency.Pulley is installed on shank support plate;Coronal axis joint plate is fixedly connected with ankle support plate;The bottom of vertical axis joint plate is rotatably connected with the coronal axis joint plate, and the rotation axis is parallel to the sagittal axis of human ankle;Rope drive system is installed on base support and connected with driving rope, driving rope is connected with sole support plate after passing through pulley;Inclination adjustment mechanism is installed on base support, moving part is installed on inclination adjustment mechanism;Arc-shaped guide rail is fixedly installed on shank support plate;Sliding block is slidingly installed on arc-shaped guide rail;The top of vertical axis joint plate is fixed with sliding block;Height adjustment mechanism is installed on sole support plate;Ankle support plate is rotatably installed on height adjustment mechanism, and the rotation axis is parallel to the coronal axis of human ankle.

Description

Technical Field

[0001] This invention relates to a cable-driven ankle joint rehabilitation robot, belonging to the field of medical rehabilitation devices. Background Technology

[0002] With an aging population and the increasing prevalence of cardiovascular and cerebrovascular diseases among younger people, the incidence of stroke and other related illnesses is rising, leading to a growing number of patients with hemiplegia, disability, and other motor dysfunctions. Stroke has become the leading cause of disability and the second leading cause of death among adults worldwide, with a high recurrence rate and numerous complications. The global medical community has listed it as one of the three major diseases threatening human health. Neurological disabilities caused by stroke and other diseases have placed a heavy burden on society and families and will have a significant impact on social and economic development. The rehabilitation of stroke patients with motor dysfunction has attracted widespread attention worldwide.

[0003] The ankle joint is a crucial component of the lower limbs. When walking, the entire body weight rests on the ankle. Running and jumping require coordinated rotation in all directions, making the ankle a vital pivot point for weight-bearing, foot pressure cushioning, and walking. Stroke patients often suffer damage to their central nervous system, leading to impaired control of movement. Common ankle problems include foot drop, inversion, and external rotation. Due to partial nerve loss, muscles cannot maintain the ankle in its normal position. Without timely rehabilitation, changes in muscle and connective tissue characteristics can occur, resulting in irreversible damage such as disuse atrophy, severely impacting daily life. Based on theories of brain plasticity and functional reorganization, early postoperative ankle rehabilitation training can significantly reduce ankle muscle stiffness and improve soft tissue extensibility and viscoelasticity, thereby promoting lower limb motor function recovery. Traditional rehabilitation therapy requires one-on-one repetitive rehabilitation training from a rehabilitation therapist. This therapist-dependent approach has the following drawbacks: (1) high labor intensity and low efficiency; (2) reliance on experience and difficulty in quantification; (3) imprecise treatment methods limit the effectiveness of rehabilitation therapy. Furthermore, my country's limited medical resources, small number of rehabilitation therapists, and high cost of rehabilitation therapy result in many patients not receiving timely and effective rehabilitation treatment, missing the optimal window for rehabilitation. Therefore, researching ankle joint rehabilitation robots to assist or even replace rehabilitation therapists in providing rehabilitation training for patients is of great significance.

[0004] In recent years, with the significant advancements in robotic intelligence and bionics, rehabilitation robots can closely mimic the techniques used by physical therapists, assisting them in treatment. Based on the high precision and repeatability of these robots, they offer higher rehabilitation efficiency and feedback capabilities compared to traditional methods. As rehabilitation robots have been a research hotspot for the past decade, universities and research institutions both domestically and internationally have designed and developed various assistive robots for daily activities and training robots for rehabilitation therapy, and these projects are gradually being commercialized through collaborations with companies.

[0005] A comprehensive analysis of current ankle rehabilitation robots reveals two main categories based on their structure: wearable and platform-based. Wearable mechanisms have limited degrees of freedom, making it difficult to meet comprehensive rehabilitation needs and impacting rehabilitation outcomes. Platform-based mechanisms typically possess multiple degrees of freedom, but some mechanisms have significant deviations between their rotation centers and the ankle's rotation center. During rehabilitation training, the ankle joint moves along with the mechanism's rotation, easily causing discomfort for the patient. Based on their actuation methods, ankle rehabilitation robots can be categorized into rigid and flexible actuation. While rigid actuation is easy to model and control, it suffers from poor compliance, high inertia, and difficulty in structural modification. Rigid linkages are prone to generating harmful impacts during rehabilitation training, leading to patient discomfort. Flexible actuation increases the mechanism's compliance and safety, but existing methods such as artificial muscles, linear cylinders, and series elastic actuators suffer from high nonlinearity and poor stability, affecting actual training effectiveness.

[0006] Compared to traditional power transmission methods such as linkage, belt, gear, and ball screw drives, rope drive is one of the most suitable drive methods for rehabilitation robots due to its excellent compliance and safety. Therefore, rope-driven rehabilitation robots have attracted increasing attention from researchers over the past decade.

[0007] The applicant filed a Chinese patent application on February 22, 2021, entitled "An Ankle Joint Rehabilitation Training Device and Robot," application number 202110200162.X. The patent includes a base, a support mechanism, a drive mechanism, and a tilt adjustment mechanism. The support mechanism includes a foot support plate, a lower leg support plate, and a rotating joint. The foot support plate is connected to the lower leg support plate via the rotating joint, and the lower leg support plate is connected to the tilt adjustment mechanism, which adjusts the tilt relative to the base. The drive mechanism includes a drive unit, multiple ropes, and multiple pulleys. At least one rope is fixed to each of the four corners of the foot support plate, and at least one pulley is fixed to both the lower leg support plate and the base. Each rope sequentially passes around a corresponding pulley on the lower leg support plate and a corresponding pulley on the base before connecting to the drive unit. This invention uses rigid components and rotating joints to provide three degrees of freedom of rotation and employs flexible rope drive to achieve precise movement of the ankle relative to the lower leg. However, this patent solution has the following drawbacks:Figure 6 As shown, its rotational joint is a revolute pair composed of two single components. The rotational axis A of the rotational joint in the vertical direction does not coincide with the rotational axis B of the ankle in the vertical direction, which is not conducive to the adduction / abduction movement of the ankle joint. Summary of the Invention

[0008] The purpose of this invention is to overcome the above-mentioned shortcomings in the prior art and provide a rope-driven ankle rehabilitation robot with higher human-machine structure matching, better flexibility and safety, and better human-machine interaction, which is conducive to improving the effect and efficiency of ankle rehabilitation training.

[0009] The technical solution adopted by this invention to solve the above problems is: a rope-driven ankle joint rehabilitation robot, comprising a moving part and a base part; the moving part includes a lower leg support plate, a rotational joint, a foot support plate, a drive rope, and a pulley; the pulley is mounted on the lower leg support plate; the foot support plate is located below the lower leg support plate; the rotational joint includes an ankle support plate, a coronal axis joint plate, and a vertical axis joint plate; the coronal axis joint plate is fixedly connected to the ankle support plate; the bottom of the vertical axis joint plate is rotatably connected to the coronal axis joint plate, and the rotation axis is parallel to the sagittal axis of the human ankle joint; the base part includes a rope drive system, a tilt adjustment mechanism, and a base support; the rope drive system is mounted on the base support... The ankle support plate is mounted on a frame and connected to a drive rope, which passes through a pulley and connects to a foot support plate. An inclination adjustment mechanism is mounted on the base support, and the moving part is mounted on the inclination adjustment mechanism. The moving part further includes a height adjustment mechanism, an arc-shaped guide rail, and a slider. The arc-shaped guide rail is fixedly mounted on the calf support plate and is perpendicular to the vertical axis of the ankle joint. The slider is slidably mounted on the arc-shaped guide rail and can rotate around the vertical axis of the ankle joint. The top of the vertical axis joint plate is fixed to the slider. The height adjustment mechanism is mounted on the foot support plate. The ankle support plate is rotatably mounted on the height adjustment mechanism, with its rotation axis parallel to the coronal axis of the ankle joint.

[0010] The calf support plate of the present invention includes an inner ring plate and an outer ring plate, with the outer ring plate fixed on the inner ring plate.

[0011] The arc-shaped guide rail described in this invention is fixedly installed at the bottom of the outer ring plate.

[0012] The arc-shaped guide rail and the inner ring plate described in this invention are arranged concentrically.

[0013] The height adjustment mechanism of the present invention includes a scissor linkage mechanism, an adjusting screw, a base, and a rotating shaft connecting block; the base is fixedly installed on the foot support plate; the scissor linkage mechanism is installed on the base; the adjusting screw is connected to the scissor linkage mechanism; the rotating shaft connecting block is installed on the scissor linkage mechanism; and the ankle support plate is rotatably installed on the rotating shaft connecting block.

[0014] The moving part of the present invention also includes a magnetic grating displacement sensor, which includes a magnetic grating read head and a magnetic grating strip. The magnetic grating read head is fixedly mounted on the slider, and the magnetic grating strip is fixedly mounted on the lower leg support plate. The magnetic grating read head and the magnetic grating strip cooperate with each other.

[0015] The rotary joint of the present invention also includes an encoder; the encoder is installed between the vertical axis joint plate and the coronal axis joint plate.

[0016] The tilt adjustment mechanism of the present invention includes a calf support plate connecting block, a calf support plate fixing shaft, and a support connecting rod; the support connecting rod is fixedly installed on the base bracket; the calf support plate connecting block is fixedly installed on the calf support plate and rotatably installed on the support connecting rod; a positioning hole is provided on the calf support plate connecting block, and the calf support plate fixing shaft is inserted into the support connecting rod and the positioning hole to fix the calf support plate connecting block and the support connecting rod.

[0017] The tilt adjustment mechanism of the present invention further includes a calf support plate pivot, and the calf support plate connecting block is rotatably mounted on the support connecting rod via the calf support plate pivot.

[0018] The leg support plate connecting block of the present invention has six positioning holes spaced at 15° intervals.

[0019] Compared with the prior art, the present invention has the following advantages and effects: 1. This expands the configuration methods for cable-driven parallel robotics, allowing for greater alignment of the rotation axis of the joint in the vertical direction with that of the ankle in the vertical direction. This facilitates plantar flexion / dorsiflexion, adduction / abduction, and inversion / eversion movements of the ankle joint. Furthermore, physical therapists can adjust the height of the mechanism's rotation center using a height adjustment mechanism to accommodate different patients' ankle heights.

[0020] 2. An inclination adjustment mechanism was designed. By adjusting the inclination angle between the movement execution part of the mechanism and the base part, users can choose a more comfortable position between lying down and sitting for rehabilitation training. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention.

[0022] Figure 2 This is a schematic diagram of the moving part in an embodiment of the present invention. Figure 1 .

[0023] Figure 3 This is a schematic diagram of the moving part in an embodiment of the present invention. Figure 2 .

[0024] Figure 4 This is a schematic diagram of the height adjustment mechanism according to an embodiment of the present invention.

[0025] Figure 5 This is a schematic diagram of the tilt adjustment mechanism according to an embodiment of the present invention.

[0026] Figure 6 This is a structural diagram of a Chinese patent with prior art application number 202110200162.X. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The following embodiments are explanations of the present invention, but the present invention is not limited to the following embodiments.

[0028] This invention includes a movement part and a base part. The movement part is mainly used to realize active and passive rehabilitation training of the ankle joint; the base part mainly provides structural support for the movement part and realizes the control and drive function. The movement part and the base part are connected by a tilt adjustment mechanism, which can adjust the tilt of the movement part relative to the base.

[0029] The moving parts include a calf support plate 1, a rotating joint 2, a foot support plate 3, a drive rope 4, a magnetic grating displacement sensor 5, a pulley 6, a height adjustment mechanism 7, an arc-shaped guide rail 8, and a slider 9.

[0030] The calf support plate 1 is used to fix the patient's calf. It includes an inner ring plate 101 and an outer ring plate 102, with the outer ring plate 102 fixed to the inner ring plate 101. The inner ring plate 101 has a diameter of 80mm, and together with the straps and cushioning pads, it ensures that the calf of patients of different body types is fixed in a comfortable position and remains still during rehabilitation. The outer ring plate 102 has a diameter of 110mm. The larger diameter allows the pulley 6 to be fixed at a more outer end, increasing the distance between the distal anchor points of the traction rope. The greater distance between the proximal and distal anchor points of the rope ensures a larger working space for the moving parts.

[0031] Four pulleys 6 with an outer diameter of 16mm are mirrored 50mm before and after the outer ring plate 102. The pulleys 6 are divided into inner and outer wheels. The inner wheel is responsible for rotating and transmitting the rope, while the outer wheel is fixed to the pulley bracket. The outer wheel is equipped with a smooth rod with anti-snagging function to prevent the rope from falling off the pulley track during rehabilitation training.

[0032] The arc-shaped guide rail 8 is fixedly installed at the bottom of the outer ring plate 102. The diameter of the arc-shaped guide rail 8 is 100mm and the arc is 60°. The arc-shaped guide rail 8 is perpendicular to the vertical axis of the human ankle joint. Optimally, the center of the arc of the arc-shaped guide rail 8 is located on the coronal axis of the human ankle joint. The slider 9 is slidably installed on the arc-shaped guide rail 8 and can move around the vertical axis of the human ankle joint on the arc-shaped guide rail 8. The arc-shaped guide rail 8 and the slider 9 serve as the joints rotating in the vertical axis direction of the mechanism. The arc-shaped guide rail 8 and the inner ring plate 101 are concentrically arranged. Because the arc-shaped guide rail 8 and the inner ring plate 101 are concentric, when the slider 9 moves relative to the arc-shaped guide rail 8, the trajectory of the slider 9 is always tangent to the arc-shaped guide rail 8, making the rotation direction of the vertical axis of the mechanism consistent with the internal / external rotation direction of the ankle joint. To obtain the rotation angle in the vertical axis direction, a magnetic grating displacement sensor 5 is provided. The magnetic grating displacement sensor 5 includes a magnetic grating read head and a magnetic grating strip. The magnetic grating read head is fixedly installed on the slider 9, and the magnetic grating strip is fixedly installed on the inner ring plate 101 of the lower leg support plate 1. The magnetic grating read head cooperates with the magnetic grating strip to read the magnetic grating strip and then convert it into an angle value, thereby measuring the angular displacement of the slider 9 during its movement.

[0033] The foot support plate 3 is located below the calf support plate 1.

[0034] The height adjustment mechanism 7 is mounted on the foot support plate 3. The height adjustment mechanism 7 is a simplified version of a scissor jack and includes a scissor linkage mechanism 71, an adjusting screw 72, a base 73, and a rotating shaft connecting block 74. The base 73 is fixedly mounted on the foot support plate 3. The scissor linkage mechanism 71 is mounted on the base 73. The adjusting screw 72 is connected to the scissor linkage mechanism 71, and the extension and retraction of the scissor linkage mechanism 71 can be driven by rotating the adjusting screw 72. The rotating shaft connecting block 74 is mounted on the scissor linkage mechanism 71, and the extension and retraction of the scissor linkage mechanism 71 drives the rotating shaft connecting block 74 to rise and fall, thereby adjusting the height of the rotating shaft connecting block 74. In the scissor linkage mechanism 71, the angle between the force-bearing link and the adjusting screw 72 is defined as the force angle. Initially, the force angle of the force-bearing link is 45°, and the distance between the center of the height adjustment mechanism and the base 73 is 80mm. With continuous adjustment of the force angle, the distance from the center of the height adjustment mechanism to the base 73 can range from 30mm to 105mm. This allows therapists to adjust the center of rotation of the movement part to align with the ankle before rehabilitation training begins, while maintaining cable tension. After adjusting the mechanism to the desired height by rotating the adjusting screw 72, the position of the adjusting screw 72 can be fixed using a self-locking nut via a screw pair. Two height adjustment mechanisms 7 are arranged side-by-side.

[0035] The rotating joint 2 includes an ankle support plate 21, a coronal axis joint plate 22, a vertical axis joint plate 23, and an encoder 24. To accommodate human ankle dimensions, the ankle support plate 21 has a diameter of 50mm. Both ends of the ankle support plate 21 are rotatably connected to the rotating shaft connecting blocks 74 of the two height adjustment mechanisms 7, with the rotation axis parallel to the coronal axis of the human ankle joint, ideally coinciding with it. One end of the coronal axis joint plate 22 is fixedly connected to the ankle support plate 21. The bottom of the vertical axis joint plate 23 is rotatably connected to the coronal axis joint plate 22, with the rotation axis parallel to the sagittal axis of the human ankle joint, ideally coinciding with it. An encoder 24 is installed between the vertical axis joint plate 23 and the coronal axis joint plate 22. The top of the vertical axis joint plate 23 is fixed to the slider 9. The rotation joint 2 can realize plantar flexion / dorsiflexion, inversion / eversion, adduction / abduction of the ankle joint. Plantar flexion / dorsiflexion is rotation about the coronal axis, inversion / eversion is rotation about the sagittal axis, and adduction / abduction is rotation about the vertical axis. The rotation angle of the rotation joint can be directly obtained by encoder 24 and magnetic grating displacement sensor 5.

[0036] The base includes a cable drive system 10, an inclination adjustment mechanism 11, and a base support 12. The base adopts a hollow structure for simplification, which reduces the manufacturing cost. Its main function is to provide structural support, cable drive, and control for the moving parts.

[0037] The rope drive system 10 is mounted on the base bracket 12 and connected to the drive rope 4. The drive rope 4 passes through the pulley 6 and is connected to the foot support plate 3.

[0038] The tilt adjustment mechanism 11 is mounted on the base bracket 12, and the moving parts are mounted on the tilt adjustment mechanism 11. The tilt adjustment mechanism 11 mainly functions to adjust the tilt of the lower leg, and includes a lower leg support plate connecting block 111, a lower leg support plate rotating shaft 112, a lower leg support plate fixing shaft 113, and a support connecting rod 114.

[0039] The support rod 114 is fixedly mounted on the base bracket 12. A groove is provided on the back of the inner ring plate 101, and the lower leg support plate connecting block 111 is fixedly mounted in the groove, thus fixing the lower leg support plate connecting block 111 to the back of the inner ring plate 101. The lower leg support plate connecting block 111 is rotatably mounted on the support rod 114 via the lower leg support plate pivot 112.

[0040] To enable patients to perform rehabilitation training while bedridden during the early stages of rehabilitation, the lower leg support plate connecting block 111 has six positioning holes 115 spaced at 15° intervals. The lower leg support plate fixing shaft 113 is inserted into the support connecting rod 114 and the positioning holes 115, fixing the lower leg support plate connecting block 111 and the support connecting rod 114 together. The tilt angle between the moving part and the base part can be adjusted through the different positioning holes 115 through which the lower leg support plate fixing shaft 113 passes. The tilt angle adjustment range is 0-90°, corresponding to the sitting rehabilitation posture, the lying rehabilitation posture, and the intermediate transition posture, respectively.

[0041] Furthermore, it should be noted that the specific embodiments described in this specification may differ in the shape and name of their components, etc. The above description is merely illustrative of the structure of the present invention. All equivalent or simple variations made based on the structure, features, and principles described in this patent concept are included within the protection scope of this patent. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to substitute them, as long as they do not deviate from the structure of the present invention or exceed the scope defined by the claims, all of which should fall within the protection scope of this invention.

Claims

1. A rope-driven ankle joint rehabilitation robot, comprising a movement part and a base part; the movement part includes a lower leg support plate, a rotational joint, a foot support plate, a drive rope, and a pulley; the pulley is mounted on the lower leg support plate; the foot support plate is located below the lower leg support plate; the rotational joint includes an ankle support plate, a coronal axis joint plate, and a vertical axis joint plate; the coronal axis joint plate is fixedly connected to the ankle support plate; the bottom of the vertical axis joint plate is rotatably connected to the coronal axis joint plate, and the rotation axis is parallel to the sagittal axis of the human ankle joint; the base part includes a rope drive system, a tilt adjustment mechanism, and a base support; the rope drive system is mounted on the base support and connected to the drive rope, the drive rope passing through the pulley and then connected to the foot support plate; the tilt adjustment mechanism is mounted on the base support, and the movement part is mounted on the tilt adjustment mechanism; characterized in that: The moving part further includes a height adjustment mechanism, an arc-shaped guide rail, and a slider; the arc-shaped guide rail is fixedly installed on the calf support plate, and the arc-shaped guide rail is perpendicular to the vertical axis of the human ankle joint; the slider is slidably installed on the arc-shaped guide rail and can rotate around the vertical axis of the human ankle joint on the arc-shaped guide rail; the top of the vertical axis joint plate is fixed to the slider; the height adjustment mechanism is installed on the foot support plate; the ankle support plate is rotatably installed on the height adjustment mechanism, and the rotation axis is parallel to the coronal axis of the human ankle joint; the calf support plate includes an inner ring plate and an outer ring plate, and the outer ring plate is fixed on the inner ring plate; the tilt adjustment mechanism includes a calf support plate connecting block, a calf support plate fixing shaft, and a support connecting rod; the support connecting rod is fixedly installed on the base bracket; the calf support plate connecting block is fixedly installed on the calf support plate and rotatably installed on the support connecting rod; the calf support plate connecting block has a positioning hole, and the calf support plate fixing shaft is inserted into the support connecting rod and the positioning hole to fix the calf support plate connecting block and the support connecting rod.

2. The cable-driven ankle rehabilitation robot according to claim 1, characterized in that: The arc-shaped guide rail is fixedly installed at the bottom of the outer ring plate.

3. The cable-driven ankle rehabilitation robot according to claim 1, characterized in that: The arc-shaped guide rail and the inner ring plate are concentrically arranged.

4. The cable-driven ankle rehabilitation robot according to claim 1, characterized in that: The height adjustment mechanism includes a scissor linkage mechanism, an adjusting screw, a base, and a rotating shaft connecting block; the base is fixedly installed on the foot support plate; the scissor linkage mechanism is installed on the base; the adjusting screw is connected to the scissor linkage mechanism; the rotating shaft connecting block is installed on the scissor linkage mechanism; and the ankle support plate is rotatably installed on the rotating shaft connecting block.

5. The cable-driven ankle rehabilitation robot according to claim 1, characterized in that: The moving part also includes a magnetic grating displacement sensor, which includes a magnetic grating read head and a magnetic grating strip. The magnetic grating read head is fixedly mounted on the slider, and the magnetic grating strip is fixedly mounted on the lower leg support plate. The magnetic grating read head and the magnetic grating strip cooperate with each other.

6. The cable-driven ankle rehabilitation robot according to claim 1, characterized in that: The rotary joint also includes an encoder; the encoder is mounted between the vertical axis joint plate and the coronal axis joint plate.

7. The cable-driven ankle rehabilitation robot according to claim 1, characterized in that: The tilt adjustment mechanism also includes a lower leg support plate pivot, and the lower leg support plate connecting block is rotatably mounted on the support connecting rod via the lower leg support plate pivot.

8. The cable-driven ankle rehabilitation robot according to claim 1, characterized in that: The leg support plate connecting block has six positioning holes spaced 15° apart.

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