A wrist joint rehabilitation training robot based on metamorphic parallel mechanism

Abstract

This invention provides a wrist joint rehabilitation training robot based on a variable-cell parallel mechanism, including an arm support and fixation device, a palm fixation device, and a variable-cell parallel mechanism. The variable-cell parallel mechanism includes a static platform, a moving platform, and four branch kinematic chains between the two platforms. The first, second, and third branch kinematic chains have the same structure, each including a revolute joint, a linear prismatic joint, a universal joint, and a ring prismatic joint. One end of the linear prismatic joint is connected to the static platform via a revolute joint, and the other end is connected to one rotation axis of the universal joint. The other rotation axis of the universal joint is connected to the moving platform via a ring prismatic joint. The fourth branch kinematic chain includes a universal joint, a linear prismatic joint, and a ball joint. One end of the linear prismatic joint is connected to the static platform via a universal joint, and the other end is connected to the moving platform via a ball joint. The variable-cell parallel mechanism drives the moving platform through the four branch kinematic chains to realize the movements required for wrist joint rehabilitation training.

Description

Technical Field

[0001] This invention belongs to the field of rehabilitation robots, specifically relating to a wrist joint rehabilitation training robot based on a variable cell parallel mechanism. Background Technology

[0002] The wrist joint is involved in various activities in daily life and work, and it is one of the most important joints in the human body. However, sports injuries, strokes, and other accidents and diseases threaten the health of the wrist joint and affect patients' normal lives. The wrist joint is the foundation for maintaining precise hand movements, bearing a large load in the support and pushing movements of the upper limbs, making it prone to injury in daily life. Wrist joint rehabilitation training is receiving increasing attention. After a wrist injury, if there is a long-term lack of exercise, it will lead to adhesion and contracture of the wrist muscles and tendons, resulting in complications such as joint swelling, pain, and limited mobility. Rehabilitation training can effectively help patients recover and prevent the condition from worsening, prevent muscle atrophy, and restore the function of the central nervous system. Compared with manual massage, wrist rehabilitation training robots are not only low-cost and easy to operate, but also convenient for patients to use at any time. Rehabilitation robots are a branch of the medical robotics field, a product of the combination of robotics technology and rehabilitation medicine. They can help patients complete effective rehabilitation training in a targeted manner, saving human resources and accurately assessing the patient's rehabilitation progress.

[0003] Many scholars in my country have applied for patents related to wrist joint rehabilitation, such as patents with application numbers 201711171694.5 and 201810867039.1. However, existing wrist joint rehabilitation devices have shortcomings in function and design, including limited movement modes, low degree of freedom, and difficulty in meeting the needs of different rehabilitation stages. Summary of the Invention

[0004] The purpose of this invention is to provide a wrist joint rehabilitation training robot based on a variable cell parallel mechanism, in order to solve the problems of general wrist joint training robots, such as single movement mode, few degrees of freedom, small range of motion, and difficulty in operation.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is: a wrist joint rehabilitation training robot based on a variable cell parallel mechanism, comprising an arm support and fixation device, a palm fixation device, and a variable cell parallel mechanism.

[0006] The variable-cell parallel mechanism includes a static platform, a moving platform, and four branch kinematic chains between the two platforms. The first, second, and third branch kinematic chains have the same structure, each including a revolute joint, a linear prismatic joint, a universal joint, and a ring prismatic joint. One end of the linear prismatic joint is connected to the static platform via a revolute joint, and the other end is connected to one rotating shaft of the universal joint. The other rotating shaft of the universal joint is connected to the moving platform via a ring prismatic joint. The fourth branch kinematic chain includes a universal joint, a linear prismatic joint, and a ball joint. One end of the linear prismatic joint is connected to the static platform via a universal joint, and the other end is connected to the moving platform via a ball joint.

[0007] The rotation axis of the first rotating joint of the first branch kinematic chain on the static platform is parallel to the rotation axis of the third rotating joint of the third branch kinematic chain and perpendicular to the rotation axis of the second rotating joint of the second branch kinematic chain; one rotation axis of the universal joint of the fourth branch kinematic chain is perpendicular to the plane of the static platform, and the other rotation axis is connected to the linear sliding joint of the fourth branch kinematic chain and is parallel to the plane of the static platform; the universal joints and annular sliding joints of the first, second, and third branch kinematic chains and the ball joint of the fourth branch kinematic chain are distributed in the plane of the moving platform, and one rotation axis of the universal joint connected to the annular sliding joint points to the centroid of the moving platform, and the other rotation axis of the universal joint is parallel to the rotation axis of the respective branch kinematic chain.

[0008] The arm support and fixing device is installed on the static platform, and the hand fixing device is installed on the moving platform;

[0009] The active pairs of the variable-cell parallel mechanism are the linear prismatic pairs of the first, second, and third branch kinematic chains and the universal joint of the fourth branch kinematic chain, and the angular displacement of the rotation axis of the universal joint connected to the stationary platform is taken as the active input.

[0010] Both the static platform and the moving platform are circular.

[0011] The linear moving pairs in the first, second, and third branch kinematic chains are driven by hydraulics, pneumatics, or electric motors.

[0012] The arm support and fixing device includes an arm support rod, an arm support ring, and an arm fixing mechanism. The arm support ring is concentric with the stationary platform. The two ends of the arm support rod are connected to the arm support ring and the stationary platform, respectively. The arm fixing mechanism is set on the arm support ring and is used to fix the arm.

[0013] The arm fixation mechanism includes a cuff and an air bladder for inflating the cuff, with the cuff distributed on the inner circular surface of the arm support ring.

[0014] The hand fixing device includes a hand support rod, a hand placement plate, and a hand fixing component. One end of the hand support rod is perpendicularly connected to the hand placement plate, and the other end is connected to the moving platform. The connection position is located at the intersection of the ball joint of the fourth branch kinematic chain and the moving platform. The axis of the hand support rod is located in the plane of the moving platform and points to the centroid of the moving platform. The hand fixing component is set on the hand placement plate and is used to fix the hand.

[0015] The hand fixation component is an elastic bandage.

[0016] The beneficial effects of the present invention are as follows: The present invention provides a variable cell parallel wrist joint rehabilitation training robot mechanism that can realize two motion modes of four degrees of freedom and three degrees of freedom. Different rehabilitation actions can be realized through the combination of the different branches: (1) driving the second branch kinematic chain alone can realize wrist palmar flexion / dorsiflexion rehabilitation training actions; (2) driving the first and third branch kinematic chains at the same time can realize wrist radial deviation / ulnar deviation actions; (3) driving the fourth branch kinematic chain alone can control the pronation / supination actions of the arm; (4) driving the first, second and third branch kinematic chains together can perform wrist joint traction and compression training, and can also realize the adjustment of the rotation center position of the moving platform to meet the rehabilitation training needs of different patients.

[0017] Therefore, this invention can utilize the motion platform of the variable cell parallel mechanism to realize the movement required for wrist joint rehabilitation training, effectively solving the problems of existing wrist rehabilitation medical devices, such as single movement mode, limited freedom of movement, difficulty in operation, and inability to meet the needs of different rehabilitation stages. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0019] Figure 2 This is a schematic diagram of the variable cell parallel mechanism in this invention;

[0020] Figure 3 This is a schematic diagram of the arm support and fixing device in this invention;

[0021] Figure 4 This is a schematic diagram of the hand-fixing device in the present invention;

[0022] The markings in the diagram are: 1. Arm support and fixation device, 101. Arm support rod, 102. Arm support ring, 103. Airbag, 104. Cuff.

[0023] 2. Hand fixation device, 201. Hand support rod, 202. Hand placement plate, 203. Elastic bandage;

[0024] 3. Variable-cell parallel mechanism: 301, ring-shaped static platform; 302, ring-shaped moving platform; L1, first branch kinematic chain; L2, second branch kinematic chain; L3, third branch kinematic chain; L4, fourth branch kinematic chain; R11, first revolute joint; R21, second revolute joint; R31, third revolute joint; P11, first linear prismatic joint; P21, second linear prismatic joint; P31, third linear prismatic joint; P41, fourth linear prismatic joint; U11, first universal joint; U21, second universal joint; U31, third universal joint; U41, fourth universal joint; Pc11, first ring-shaped prismatic joint; Pc21, second ring-shaped prismatic joint; Pc31, third ring-shaped prismatic joint; S41, ball joint. Detailed Implementation

[0025] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the invention in any way.

[0026] See attached document Figure 1-4 As shown, a wrist joint rehabilitation training robot based on a variable cell parallel mechanism includes an arm support and fixation device 1, a palm fixation device 2, and a variable cell parallel mechanism 3.

[0027] like Figure 2 As shown, the variable cell parallel mechanism includes a first branch kinematic chain, a second branch kinematic chain, a third branch kinematic chain, a fourth branch kinematic chain, a ring-shaped static platform, and a ring-shaped moving platform.

[0028] The first, second, and third branch kinematic chains have the same structure and the same connection method as the annular stationary platform and the annular moving platform. Therefore, the first branch kinematic chain will be used as an example for detailed explanation. The first branch kinematic chain includes a first revolute joint R11, a first linear prismatic joint P11, a first universal joint U11, and a first annular prismatic joint Pc11. One end of the first linear prismatic joint P11 is connected to the annular stationary platform 301 through the first revolute joint R11, allowing the first linear prismatic joint P11 to rotate relative to the annular stationary platform 301. The other end of the first linear prismatic joint P11 is connected to the first universal joint U11. The first universal joint U11 is directly connected to the annular moving platform 302 through the first annular prismatic joint Pc11, allowing the first annular prismatic joint Pc11 to rotate on the annular moving platform 302. The fourth branch kinematic chain L4 includes a fourth universal joint U41, a fourth linear prismatic joint P41, and a ball joint S41. The fourth linear prismatic joint P41 is connected to the annular stationary platform 301 and the annular moving platform 302 through the fourth universal joint U41 and the ball joint S41, respectively, so as to realize the movement of the fourth linear prismatic joint P41 relative to the annular stationary platform 301 and relative to the annular moving platform 302.

[0029] Furthermore, the rotation axis of the first revolute joint R11 of the first branch kinematic chain L1 on the annular stationary platform 301 is parallel to the rotation axis of the third revolute joint R31 of the third branch kinematic chain L3, and perpendicular to the rotation axis of the second revolute joint R21 of the second branch kinematic chain L2; one rotation axis of the fourth universal joint U41 in the fourth branch kinematic chain L4 is perpendicularly mounted on the plane of the annular stationary platform 301, and the other rotation axis is connected to the fourth linear sliding joint P41 and is parallel to the annular stationary platform 301; and the revolute joints in the first, second, and third branch kinematic chains and the fourth universal joint U41 of the fourth branch kinematic chain L4 are evenly distributed along the circumference on the annular stationary platform 301. The universal joints and annular sliding joints in the first, second, and third branch kinematic chains and the ball joint S41 of the fourth branch kinematic chain L4 are distributed in the plane of the annular moving platform 302, and the rotation axis of the universal joint connected to the annular sliding joint points to the centroid of the annular moving platform 302, and the other rotation axis of the universal joint is parallel to the axis of the revolute joint of its respective branch kinematic chain.

[0030] The active pairs of the variable-cell parallel mechanism 3 are the linear gliding pairs of the first, second, and third branch kinematic chains (L1, L2, L3) and the fourth universal joint U41 of the fourth branch kinematic chain L4, with the angular displacement of the rotation axis of the fourth universal joint U41 connected to the annular static platform 301 as the active input. The linear gliding pairs in the first, second, and third branch kinematic chains are hydraulically or pneumatically driven, for example, by hydraulic rods or pneumatic rods, or by electric motors, such as electric push rods. The fourth universal joint U41 in the fourth branch kinematic chain L4 is driven by an electric motor.

[0031] like Figure 3 As shown, the arm support and fixing device 1 includes an arm support rod 101, an arm support ring 102, an airbag 103, and a cuff 104. The arm support ring 102 is located within the area enclosed by the annular stationary platform 301, and the arm support ring 102 is concentric with the annular stationary platform 301. One end of the arm support rod 101 is connected to the arm support ring 102, and the other end is fixed to the stationary platform 301, with the connection point located at the intersection of the axis of the fourth universal joint U41 of the fourth branch L4 kinematic chain and the annular stationary platform 301. The cuff 104 is distributed along the circumference of the arm support ring 102 on the inner side of the arm support ring 102 and communicates with the airbag 103 located on the outer circumference of the arm support ring 102. The airbag 103 inflates the cuff 104 to clamp and fix the arm. During use, the inflation amount of the cuff is adjusted by the airbag, thereby adjusting the degree of clamping and fixing of the arm, or adapting to different arm sizes.

[0032] like Figure 4As shown, the hand fixation device 2 includes a hand support rod 201, a hand placement plate 202, and an elastic bandage 203. One end of the hand support rod 201 is vertically connected to the hand placement plate 202, and the other end is connected to the annular moving platform 302. The connection point is located at the intersection of the ball joint S41 of the fourth branch kinematic chain L4 and the annular moving platform 302, and the axis of the hand support rod 201 lies in the plane of the annular moving platform 302 and points towards the centroid of the annular moving platform 302. The elastic bandage 203 is located on the hand support plate 202, and the hand is fixed by the elastic bandage 203.

[0033] When using this invention, the user's arm extends into the annular static platform and the annular dynamic platform. The arm is fixed by an arm support and fixation device, and the hand is fixed by a hand fixation device. After fixation, driving the second branch kinetic chain L2 alone can achieve wrist flexion / dorsiflexion movements; driving the first branch kinetic chain L1 and the third branch kinetic chain L3 simultaneously can achieve wrist radial / ulnar deviation movements; driving the fourth branch kinetic chain L4 alone can achieve arm pronation / supination movements. The first, second, and third branch kinetic chains work together to traction and compress the wrist joint, and the position of the dynamic platform can also be adjusted to meet the needs of different patients.

[0034] This invention provides a variable-cell parallel wrist joint rehabilitation training robot mechanism capable of realizing both four-degree-of-freedom and three-degree-of-freedom motion modes. The variable-cell parallel mechanism 3 drives a ring-shaped moving platform 302 via four branch kinematic chains to achieve wrist flexion / dorsiflexion, radial / ulnar deviation, forearm-direction movement, and forearm pronation / supination. The first branch kinematic chain L1 and the third branch kinematic chain L3 jointly complete the radial / ulnar deviation rehabilitation training movements of the wrist; the second branch kinematic chain L2 can independently complete the wrist flexion / dorsiflexion movements; the fourth branch kinematic chain L4 controls the forearm pronation / supination movements, and the activation of this training function can be selected by locking or deactivating the active pair in this branch. Simultaneously, the movements of the first three branch kinematic chains can jointly achieve movement along the forearm axis, completing traction and compression of the wrist joint and adjusting the position of the hand fixation device.

[0035] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Those skilled in the art should understand that modifications or equivalent substitutions can be made to the specific implementation of the present invention with reference to the above embodiments. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention are within the protection scope of the pending claims.

Claims

1. A wrist rehabilitation training robot based on a metamorphic parallel mechanism, comprising an arm support fixing device, a palm fixing device and a metamorphic parallel mechanism, characterized in that: The variable-cell parallel mechanism comprises a static platform, a dynamic platform and four branch kinematic chains between the two platforms, wherein the first, second and third branch kinematic chains have the same structure, each comprising a revolute pair, a linear moving pair, a universal joint and a ring moving pair, one end of the linear moving pair is connected with the static platform through the revolute pair, the other end is connected with one rotation axis of the universal joint, the other rotation axis of the universal joint is connected with the dynamic platform through the ring moving pair, and the fourth branch kinematic chain comprises a universal joint, a linear moving pair and a spherical pair, one end of the linear moving pair is connected with the static platform through the universal joint, and the other end is connected with the dynamic platform through the spherical pair. The rotation axis of the first revolute pair of the first branch kinematic chain on the static platform is parallel to the rotation axis of the third revolute pair of the third branch kinematic chain, and is perpendicular to the rotation axis of the second revolute pair of the second branch kinematic chain; one rotation axis of the universal joint of the fourth branch kinematic chain is perpendicular to the plane of the static platform, the other rotation axis is connected with the linear moving pair of the fourth branch kinematic chain and is parallel to the plane of the static platform; the universal joints and the ring moving pairs in the first, second and third branch kinematic chains and the spherical pair of the fourth branch kinematic chain are distributed in the plane of the dynamic platform, and one rotation axis of the universal joint connected with the ring moving pair points to the centroid of the dynamic platform, and the other rotation axis is parallel to the rotation axes of the revolute pairs of the respective branch kinematic chains. The arm supporting and fixing device is arranged on the static platform, and the palm fixing device is arranged on the dynamic platform. The driving pairs of the variable-cell parallel mechanism are respectively the linear moving pairs of the first, second and third branch kinematic chains and the universal joints of the fourth branch kinematic chain, and the angular displacement of the rotation axis of the universal joint connected with the static platform is the driving input, and the universal joints of the fourth branch kinematic chain are driven by motors. The static platform and the dynamic platform are both circular rings. The arm supporting and fixing device comprises an arm supporting rod, an arm supporting ring and an arm fixing mechanism, one end of the arm supporting rod is connected with the arm supporting ring, the other end is fixed to the static platform, and the connection position is located on the intersection of the fourth rotation axis of the fourth branch kinematic chain and the static platform, and the arm fixing mechanism is arranged on the arm supporting ring and used for fixing the arm. The palm fixing device comprises a palm supporting rod, a palm placing plate and a palm fixing member, one end of the palm supporting rod is connected with the palm placing plate perpendicularly, the other end is connected with the dynamic platform, and the connection position is located on the intersection of the spherical pair of the fourth branch kinematic chain and the dynamic platform; the axis of the palm supporting rod is located in the plane of the dynamic platform and points to the centroid of the dynamic platform; and the palm fixing member is arranged on the palm placing plate and used for fixing the palm.

2. The wrist rehabilitation training robot based on the metamorphic parallel mechanism according to claim 1, characterized in that: The linear moving pairs in the first, second and third branch kinematic chains are driven by hydraulic pressure, air pressure or motors.

3. The wrist rehabilitation training robot based on the metamorphic parallel mechanism according to claim 1, characterized in that: The arm supporting ring is concentric with the static platform.

4. The wrist rehabilitation training robot based on the metamorphic parallel mechanism according to claim 1, characterized in that: The arm fixing mechanism comprises a sleeve and an air bag for inflating the sleeve, and the sleeve is distributed on the inner circular surface of the arm supporting ring.

5. The wrist rehabilitation training robot based on the metamorphic parallel mechanism according to claim 1, characterized in that: The palm fixing member is an elastic bandage.

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