A non-orthogonal design shoulder joint five-degree-of-freedom isokinetic muscle strength evaluation and rehabilitation platform
By designing a non-orthogonal five-DOF isokinetic muscle strength assessment and rehabilitation platform for the shoulder joint, the problem of the singularity of traditional single-joint single-DOF assessment is solved. It simulates shoulder girdle movement, reduces the risk of shoulder injury, and improves the accuracy and efficiency of assessment and rehabilitation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HARBIN INSTITUTE OF TECHNOLOGY (SHENZHEN) (INSTITUTE OF SCIENCE AND TECHNOLOGY INNOVATION HARBIN INSTITUTE OF TECHNOLOGY SHENZHEN)
- Filing Date
- 2023-12-28
- Publication Date
- 2026-06-30
AI Technical Summary
Traditional single-joint, single-degree-of-freedom isokinetic rehabilitation and assessment methods are limited and cannot fully consider the complex movements of the shoulder joint. They neglect the movement of the scapular girdle, increasing the risk of shoulder injury for users.
A non-orthogonal five-DOF isokinetic muscle strength assessment and rehabilitation platform for the shoulder joint was designed, including four active degrees of freedom and one passive degree of freedom. The movement of the scapular girdle is simulated through the two-DOF acromioclavicular joint, sternoclavicular joint, and the three-DOF glenohumeral ball-and-socket joint. The passive degree of freedom is realized by using slewing bearings, guide rails, and sliders, while the active degree of freedom is realized by joint servo motors and reducers. A non-orthogonal coordinate system is established to reduce space occupation and center of gravity.
It enables multi-degree-of-freedom muscle strength assessment and rehabilitation training, reduces the risk of shoulder injury, improves the accuracy of assessment and rehabilitation efficiency, and adapts to the needs of different groups of people.
Smart Images
Figure CN117752516B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of isokinetic muscle strength assessment and joint rehabilitation equipment, and in particular to a non-orthogonal design five-degree-of-freedom isokinetic muscle strength assessment and rehabilitation platform for the shoulder joint. Background Technology
[0002] An exoskeleton rehabilitation training system is a robotic rehabilitation aid designed to assist patients in performing rehabilitation exercises and restoring function. It provides strength support and movement assistance through robotic devices to enhance muscle strength and mobility. Exoskeleton rehabilitation devices not only reduce the workload of physical therapists and save on rehabilitation costs, but also provide objective data to evaluate the patient's rehabilitation progress, facilitating the development of appropriate rehabilitation strategies by physical therapists.
[0003] With the introduction of the concept of isokinetic exercise and the advent of isokinetic instruments, isokinetic muscle strength training technology has been gradually applied in the fields of sports medicine and rehabilitation medicine, and has broad application prospects. Isokinetic muscle strength training technology refers to a method of muscle strength training using isokinetic instruments based on isokinetic exercise. In isokinetic muscle strength training, the movement speed is constant, while the resistance can be adjusted as needed. The subject trains according to a preset limb movement speed, and the torque output of the isokinetic instrument changes with the increase or decrease of muscle tension to ensure that the limb does not generate acceleration. Isokinetic muscle strength instruments can assess and rehabilitate individuals with motor dysfunction, and can also assist athletes in training.
[0004] Isokinetic muscle strength testers offer isokinetic, isometric, isotonic, concentric, and eccentric training modes. The isokinetic training mode ensures joint rehabilitation safety and improves the accuracy of muscle strength assessment. Commonly used test parameters include peak torque, peak torque angle, average power, and total muscle work. Traditional isokinetic muscle strength testers employ single-joint, single-degree-of-freedom assessment and rehabilitation strategies. For different joint movements, mechanical adapters are required, enabling a single paradigm of assessment and rehabilitation exercise. This design can only meet the training needs of specific joints. Multi-joint isokinetic muscle strength testers, however, can achieve multi-joint, multi-degree-of-freedom assessment and rehabilitation, providing possibilities for more comprehensive training.
[0005] The shoulder joint is a complex joint in the human upper limb, comprising the glenohumeral, acromioclavicular, sternoclavicular, and scapular joints. It has the largest range of motion and the most diverse range of movements in the human body. Shoulder joint movements include internal rotation, external rotation, abduction, adduction, forward / backward / upward extension, and forward / backward rotation. From a musculoskeletal perspective, the human shoulder complex joint is actually composed of a three-degree-of-freedom glenohumeral ball-and-socket joint and two-degree-of-freedom acromioclavicular and sternoclavicular joints. The acromioclavicular and sternoclavicular joints are responsible for elevation, descent, extension, and retraction of the scapula. Traditional exoskeleton rehabilitation robots use ball-and-socket joints to provide the three degrees of freedom for shoulder movement, neglecting the movement of the scapular girdle. However, the scapular girdle plays a crucial role, connecting the scapula to the skeletal skeleton and influencing the shoulder's anatomy and range of motion. Ignoring scapular girdle movement can lead to human-machine joint mismatch, increasing the risk of shoulder injury or damage. Therefore, the kinematic structure of exoskeleton rehabilitation robots must consider scapular girdle movement. Summary of the Invention
[0006] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is that the traditional single-joint single-degree-of-freedom isokinetic rehabilitation and assessment paradigm is too simplistic and cannot fully take into account the compensation of other joints; moreover, it only uses three degrees of freedom to simulate ball-and-socket joints without considering the combination of actual movements.
[0007] To achieve the above objectives, this invention provides a non-orthogonal design five-DOF isokinetic muscle strength assessment and rehabilitation platform for the shoulder joint. The platform comprises four active degrees of freedom and one passive degree of freedom, including a two-DOF acromioclavicular and sternoclavicular joints and a three-DOF glenohumeral ball-and-socket joint. The two-DOF acromioclavicular and sternoclavicular joints mainly include a slewing bearing, a guide rail, a slider, a first joint servo motor, a first motor mount, a first reducer, and a coupling. The three-DOF glenohumeral ball-and-socket joint mainly includes second to fourth joint servo motors, second to fourth motor mounts, second to fourth reducers, a coupling, and an upper arm fixation plate.
[0008] The active degrees of freedom are achieved by joint servo motors and reducers, while the passive degrees of freedom are achieved by slewing bearings, guide rails, and sliders. The two-degree-of-freedom acromioclavicular and sternoclavicular joints are connected to the three-degree-of-freedom glenohumeral ball-and-socket joints through fasteners, enabling multi-degree-of-freedom muscle strength assessment and rehabilitation training of the shoulder joint in multiple paradigms, including adduction and abduction, internal and external rotation, and extension and flexion.
[0009] Furthermore, the two-degree-of-freedom acromioclavicular and sternoclavicular joints include passive degrees of freedom for extension and retraction and active degrees of freedom for elevation and descent. The two degrees of freedom form a pair of coordinate systems that are perpendicular to each other and parallel to the human joints, thereby simulating the movement of the scapular girdle. The passive degrees of freedom for extension and retraction are passively realized by the slewing bearing, guide rail, and slider, while the active degrees of freedom for elevation and descent are actively realized by the first joint servo motor and the first reducer. The first joint servo motor and the first reducer are connected by fasteners.
[0010] Furthermore, the passive degrees of freedom of extension and retraction of the two-degree-of-freedom acromioclavicular and sternoclavicular joints are replaced by the combination of the rotational motion of the slewing bearing and the linear motion of the guide rail slider. The guide rail and slider are set on the slewing bearing, parallel to the clavicle, and the range of motion of the slider is limited according to the range of motion of the human body, so that the two-degree-of-freedom acromioclavicular and sternoclavicular joints can always ensure that the origin of the three-degree-of-freedom glenohumeral ball-and-socket joint coincides with the intersection of the rotational shafts of the second to fourth joint servo motors of the three degrees of freedom while rotating.
[0011] Furthermore, for the active degrees of freedom of the two-degree-of-freedom acromioclavicular and sternoclavicular joints in raising and lowering, the size of the second motor seat is designed specifically for different patients to ensure that the second motor seat and the human acromioclavicular part remain approximately relatively stationary when the two-degree-of-freedom acromioclavicular and sternoclavicular joints rotate.
[0012] Furthermore, the two-degree-of-freedom shoulder lock and chest lock joint also includes a base, a guide rail base, and two first motor base support ribs; the base is composed of alloy profiles, alloy profile corner brackets, and sliding nuts, and the two first motor base support ribs clamp the first motor bases with fasteners to ensure the stability of the mechanism above the first motor bases.
[0013] Furthermore, the three-degree-of-freedom glenohumeral ball-and-socket joint is designed with a non-orthogonal basis. When a person is standing normally, the ball-and-socket joint of the human shoulder is used as the origin, a set of mutually perpendicular vectors in the horizontal plane are used as the x-axis and y-axis, and a vector with an angle of 45° with the direction of gravity is used as the z-axis to establish a three-dimensional non-orthogonal coordinate system. The motor axis coincides with the coordinate axis. Therefore, the servo motor axes of the second to fourth joints are in two sets of orthogonal relationships and one set with an angle of 45°.
[0014] Furthermore, the three-degree-of-freedom glenohumeral ball-and-socket joint also includes a second output plate and a third output plate; the servo motors of the second to fourth joints are designed in series, the output end of the second joint servo motor is connected to the second output plate and the third motor mount, and the second output plate and the third motor mount form a 135° angle; the output end of the third joint servo motor is connected to the third output plate and the fourth motor mount, and the third output plate and the fourth motor mount form a 90° angle; the output end of the fourth joint servo motor is connected to the upper arm fixing plate.
[0015] Furthermore, the bosses at the front ends of the first to fourth reducers are all embedded in the holes of the corresponding first to fourth motor mounts to ensure concentricity and installation accuracy.
[0016] Furthermore, the first to fourth reducers use couplings for output. The fixed side and the deformable side of the coupling are connected by fasteners. By using the clamping force on the output shaft of the reducer, the load is driven to work through friction. At the same time, the fasteners are screwed into the output shaft of the reducer through the holes of the load to prevent axial movement of the coupling.
[0017] Furthermore, the upper arm fixing plate is equipped with straps for fixing the human body and the device. The upper arm fixing plate has straight slots at different positions for fixing the straps, which can be used to adapt to different people. The position of the straps can be adjusted as needed to meet the needs of different people.
[0018] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention solves the problem of the limited paradigm of rehabilitation and assessment in traditional single-joint, single-degree-of-freedom isokinetic instruments. Through the cooperation of various actuators, it can achieve multi-degree-of-freedom muscle strength assessment and rehabilitation training of shoulder joint adduction and abduction, internal and external rotation, and extension and flexion without changing mechanical adapters. Simultaneously, it fully considers the movement of the shoulder girdle, approximating the acromioclavicular and sternoclavicular joints as a two-degree-of-freedom model, corresponding to the forward extension and retraction, and elevation and descent of the acromioclavicular and sternoclavicular regions, respectively. The forward extension and retraction degree of freedom is replaced by a combination of rotary bearing rotational motion and linear motion of slider and guide rail, which is a passive degree of freedom. The elevation and descent degree of freedom is actively achieved by a motor, which is an active degree of freedom. This method avoids the user injury problem caused by insufficient degrees of freedom in traditional shoulder joint rehabilitation exoskeletons and reduces the possibility of movement interference between the mechanical body and the human body during actual operation. For the three-degree-of-freedom glenohumeral ball-and-socket joint in the shoulder joint, a non-orthogonal design is adopted. A non-orthogonal reference system is established with the ball-and-socket joint of the human shoulder as the origin when the person is standing normally. This saves space, lowers the overall center of gravity of the device, and reduces the impact of the mechanism's own weight on control. This design improves the accuracy of joint muscle strength assessment and the efficiency of rehabilitation.
[0019] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description
[0020] Figure 1 This is an assembly drawing of an exoskeleton-type five-DOF shoulder joint isokinetic muscle strength assessment and rehabilitation platform according to a preferred embodiment of the present invention;
[0021] Figure 2 This is a schematic diagram of a two-degree-of-freedom acromioclavicular and sternoclavicular joint according to a preferred embodiment of the present invention;
[0022] Figure 3This is a left view of a three-degree-of-freedom glenohumeral ball-and-socket joint according to a preferred embodiment of the present invention;
[0023] Figure 4 This is a front view of a three-degree-of-freedom glenohumeral ball-and-socket joint according to a preferred embodiment of the present invention;
[0024] Wherein: 100: Two-degree-of-freedom shoulder lock, sternocleidomastoid joint; 101: Alloy profile; 102: Alloy profile corner bracket; 103: Slewing bearing; 104: Guide rail base; 105: Guide rail; 106: Slider; 107: Limiting block; 108: Aluminum plate base; 109: First motor base support rib; 110: First motor base; 111: First joint servo motor; 112: First reducer; 113: First coupling fixed side; 114: First coupling deformable side; 115: Second motor base; 200: Three-degree-of-freedom glenohumeral ball-and-socket joint; 201: Second joint servo motor; 208: Third... 215: Fourth joint servo motor; 202: Second reducer; 209: Third reducer; 216: Fourth reducer; 203: Second coupling fixed side; 204: Second coupling deformable side; 210: Third coupling fixed side; 211: Third coupling deformable side; 217: Fourth coupling fixed side; 218: Fourth coupling deformable side; 206: Non-orthogonal connector; 213: Orthogonal connector; 205: Second output aluminum plate; 207: Third motor mount; 212: Third output aluminum plate; 214: Fourth motor mount; 219: Boom fixing plate; 220: Strap. Detailed Implementation
[0025] The following description, with reference to the accompanying drawings, illustrates several preferred embodiments of the present invention to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.
[0026] In the accompanying drawings, components with the same structure are indicated by the same numerical designation, and components with similar structures or functions are indicated by similar numerical designations. The dimensions and thicknesses of each component shown in the drawings are arbitrary, and the present invention does not limit the dimensions and thicknesses of each component. To make the illustrations clearer, the thickness of some components has been appropriately exaggerated in the drawings.
[0027] like Figure 1As shown, the overall structure of this invention can be divided into two parts based on the characteristics of the human shoulder joint: a two-degree-of-freedom acromioclavicular and sternoclavicular joint 100 and a three-degree-of-freedom glenohumeral ball-and-socket joint 200. The active degrees of freedom are achieved by a joint servo motor and a reducer, while the passive degrees of freedom are achieved by a slewing bearing 103, a guide rail 105, and a slider 106. The two-degree-of-freedom acromioclavicular and sternoclavicular joint 100 and the three-degree-of-freedom glenohumeral ball-and-socket joint 200 are connected by fasteners, enabling multi-degree-of-freedom muscle strength assessment and rehabilitation training of the shoulder joint in multiple paradigms, including adduction / abduction, internal / external rotation, and extension / flexion.
[0028] like Figure 2 As shown, the two-degree-of-freedom shoulder lock / chest lock joint 100 includes a base, a slewing bearing 103, a first joint servo motor 111, a first reducer 112, a guide rail 105, a slider 106, and related components. In the two-degree-of-freedom shoulder lock / chest lock joint 100, the base is a frame composed of an alloy profile 101, alloy profile brackets 102, sliding nuts, and fasteners. The base is fixed to ensure overall stability.
[0029] The two-degree-of-freedom acromioclavicular and sternoclavicular joint 100 includes passive degrees of freedom for extension and retraction and active degrees of freedom for elevation and descent. The passive degrees of freedom for extension and retraction are passively realized by the slewing bearing 103, guide rail 105, and slider 106. The active degrees of freedom for elevation and descent are actively realized by the first joint servo motor 111 and the first reducer 112. The first joint servo motor 111 and the first reducer 112 are connected by fasteners to form a pair of coordinate systems that are perpendicular to each other and parallel to the human joints, thereby simulating the movement of the scapular girdle.
[0030] For the passive degrees of freedom of the two-degree-of-freedom acromioclavicular and sternoclavicular joints 100—extension and retraction—the involvement of human muscles in this degree of freedom is complex and relatively small. Therefore, it is replaced by the combined rotational motion of the slewing bearing 103 and the linear motion of the guide rail 105 and slider 106. The guide rail 105 and slider 106 are mounted on the slewing bearing 103, parallel to the clavicle. The range of motion of the slider 106 is limited according to the range of motion of the human body, ensuring that the origin of the three-degree-of-freedom glenohumeral ball-and-socket joint 200 coincides with the rotation axis of the second to fourth joint servo motors of the three degrees of freedom while the two-degree-of-freedom acromioclavicular and sternoclavicular joints 100 rotates. The outer ring of the slewing bearing 103 is connected to the base via fasteners, and the inner ring is fixed to the guide rail base 104 via fasteners. The bottom surface of the guide rail base 104 has a boss embedded in the inner ring of the slewing bearing 103 to ensure concentricity. Two guide rails 105 are fixedly connected to the guide rail base 104 by fasteners. The grooves on the surface of the guide rail base 104 ensure the parallelism of the guide rails 105 during installation. Limit blocks 107 are located at both ends of the guide rails 105. The positions of the limit blocks 107 are determined by the range of motion of the human body and are fixedly connected to the guide rail base 104 by fasteners to prevent the slider 106 from dislodging. The aluminum plate base 108 and the first motor base support rib 109 are fixed to the slider 106 by fasteners. The slider 106 is embedded in the groove on the bottom surface of the aluminum plate base 108 to ensure installation accuracy. The two first motor base support ribs 109 clamp the first motor base 110 with fasteners to ensure the stability of the mechanism above the first motor base 110.
[0031] The two-degree-of-freedom acromioclavicular and sternoclavicular joints 100 have their lifting and lowering degrees of freedom achieved by a first joint servo motor 111. The first joint servo motor 111 is fixed to a first reducer 112 via fasteners, and the first reducer 112 is fixed to a first motor mount 110 via fasteners. A boss at the front end of the first reducer 112 is embedded in the first motor mount 110 to ensure concentricity during installation. The fixed side 113 and the deformable side 114 of the first coupling are connected by fasteners. The load is driven by friction through the clamping force on the output shaft of the first reducer 112. The fixed side 113 of the coupling is connected to a second motor mount 115 via fasteners. Fasteners are screwed into the threads on the output shaft of the first reducer 112 via the second motor mount 115 to prevent axial movement of the coupling. Before use, the appropriate dimensions of the second motor mount 115 are designed for different patients to ensure that this component remains approximately stationary relative to the acromioclavicular joint during mechanism rotation.
[0032] like Figure 3 and Figure 4The image shows the left and front views of a three-degree-of-freedom glenohumeral ball-and-socket joint 200 with the human body's frontal view as the positive direction. The three-degree-of-freedom glenohumeral ball-and-socket joint 200 includes a second joint servo drive motor 201, a third joint servo drive motor 208, a fourth joint servo drive motor 215, a second reducer 202, a third reducer 209, a fourth reducer 216, a coupling, an upper arm fixing plate 219, a strap 220, and other related components. To avoid motion interference between the mechanical body and the human body during actual operation, the three-degree-of-freedom glenohumeral ball-and-socket joint 200 is designed using a non-orthogonal basis. When a person is standing normally, a three-dimensional non-orthogonal coordinate system is established with the human shoulder joint socket as the origin, a set of mutually perpendicular vectors in the horizontal plane as the x-axis and y-axis, and a vector at a 45° angle to the direction of gravity as the z-axis. The motor axes coincide with the coordinate axes; therefore, two sets of coordinate axes of the three joint servo motor axes are orthogonal, and one set has an angle of 45°. The second joint servo motor 201 is fixedly connected to the second reducer 202 via fasteners, and the second reducer 202 is fixedly connected to the second motor base 115 via fasteners. A boss at the front end of the second reducer 202 is embedded in the second motor base 115 to ensure concentricity during installation. The fixed side 203 and the deformable side 204 of the second coupling are connected by fasteners, utilizing the clamping force on the output shaft of the second reducer 202 to drive the load through friction. The fixed side 203 of the second coupling is connected to the second output aluminum plate 205 via fasteners. The fasteners are screwed into the threads on the output shaft of the second reducer 202 via the second output aluminum plate 205 to prevent axial movement of the coupling. Due to the non-orthogonal design, the second output aluminum plate 205 forms a 135° angle with the third motor base 207 and is connected to the fasteners via a non-orthogonal connector 206. The third joint servo motor 208 is fixedly connected to the third reducer 209 via fasteners. The third reducer 209 is fixedly connected to the third motor mount 207 via fasteners. The boss at the front end of the third reducer 209 is embedded in the third motor mount 207 to ensure concentricity during installation. The fixed side 210 and the deformable side 211 of the third coupling are connected by fasteners. The load is driven by friction through the clamping force on the output shaft of the third reducer 209. The fixed side 210 of the third coupling is connected to the third output aluminum plate 212 via fasteners. The fasteners are screwed into the threads on the output shaft of the reducer 209 via the third output aluminum plate 212 to prevent axial movement of the coupling. The third output aluminum plate 212 forms a 90° angle with the fourth motor mount 214 and is connected to the fasteners via orthogonal connector 213. The joint servo motor 215 is fixedly connected to the fourth reducer 216 via fasteners. The fourth reducer 216 is fixedly connected to the fourth motor mount 214 via fasteners. The boss at the front end of the fourth reducer 216 is embedded in the fourth motor base 214 to ensure concentricity during installation. The fixed side 217 and the deformable side 218 of the fourth coupling are connected by fasteners. The load is driven by friction through the clamping force on the output shaft of the fourth reducer 216.The coupling fixing side 217 is connected to the upper arm fixing plate 219 via fasteners. The fasteners are screwed into the threads on the output shaft of the fourth reducer 216 via the upper arm fixing plate 219 to prevent axial movement of the coupling. The upper arm fixing plate 219 has straight slots for fixing the strap 220, which connects to the upper arm. The strap 220 can be adjusted on the upper arm fixing plate 219 according to different upper arm positions to meet the testing and rehabilitation needs of different groups. During use, the base position is adjusted according to the subject's arm and shoulder joint and fixed using aluminum profile angle brackets 102. The lengths of the second motor mount 115, second output aluminum plate 205, third motor mount 207, third output aluminum plate 212, and fourth motor mount 214 are determined based on the human shoulder joint dimensions. The subject fixes their arm using the strap 220. The subject then performs corresponding rehabilitation movements under the doctor's guidance, recording muscle strength parameters, movement speed, angle, torque, and other information.
[0033] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.
Claims
1. A non-orthogonal designed shoulder joint five degrees of freedom isokinetic muscle strength evaluation and rehabilitation platform, characterized in that, The system consists of five degrees of freedom, comprising four active degrees of freedom and one passive degree of freedom, including a two-degree-of-freedom acromioclavicular joint, a sternoclavicular joint, and a three-degree-of-freedom glenohumeral ball-and-socket joint. The two-degree-of-freedom acromioclavicular and sternoclavicular joints mainly include a slewing bearing, a guide rail, a slider, a first joint servo motor, a first motor mount, a first reducer, and a coupling. The three-degree-of-freedom glenohumeral ball-and-socket joint mainly includes second to fourth joint servo motors, second to fourth motor mounts, second to fourth reducers, a coupling, and a boom fixation plate. The active degrees of freedom are achieved by the joint servo motor and reducer, while the passive degrees of freedom are achieved by the slewing bearing, the guide rail, and the slider. The two-degree-of-freedom acromioclavicular and sternoclavicular joints are connected to the three-degree-of-freedom glenohumeral ball-and-socket joint by fasteners, enabling multi-degree-of-freedom muscle strength assessment and rehabilitation training of the shoulder joint in multiple paradigms of adduction, abduction, internal and external rotation, and extension and flexion. The two-degree-of-freedom acromioclavicular and sternoclavicular joints include passive degrees of freedom for extension and retraction and active degrees of freedom for elevation and descent. The passive degrees of freedom for extension and retraction and the active degrees of freedom for elevation and descent form a pair of coordinate systems that are perpendicular to each other and parallel to the human joints, thereby simulating the movement of the scapular girdle. The passive degrees of freedom for extension and retraction are passively realized by the slewing bearing, the guide rail, and the slider. The active degrees of freedom for elevation and descent are actively realized by the first joint servo motor and the first reducer. The first joint servo motor and the first reducer are connected by fasteners. The three-degree-of-freedom glenohumeral ball-and-socket joint is designed with a non-orthogonal basis. When a person is standing normally, the ball-and-socket joint of the human shoulder is used as the origin, a set of mutually perpendicular vectors in the horizontal plane are used as the x-axis and y-axis, and a vector with an angle of 45° with the direction of gravity is used as the z-axis to establish a three-dimensional non-orthogonal coordinate system. The motor axis coincides with the coordinate axis. Therefore, the servo motor axes of the second to fourth joints are in two sets of orthogonal and one set with an angle of 45°. The three-degree-of-freedom glenohumeral ball-and-socket joint also includes a second output plate and a third output plate; the second to fourth joint servo motors are designed in series, the output end of the second joint servo motor is connected to the second output plate and the third motor base, and the second output plate and the third motor base form a 135° angle; the output end of the third joint servo motor is connected to the third output plate and the fourth motor base, and the third output plate and the fourth motor base form a 90° angle; the output end of the fourth joint servo motor is connected to the upper arm fixing plate.
2. A non-orthogonal designed shoulder joint five degree of freedom isokinetic muscle strength evaluation and rehabilitation platform according to claim 1, characterized in that, The passive degrees of freedom of the two-degree-of-freedom acromioclavicular and sternoclavicular joints—extending and retracting—are replaced by the combined rotational motion of the slewing bearing and the linear motion of the guide rail slider. The guide rail and the slider are mounted on the slewing bearing, parallel to the clavicle. The range of motion of the slider is limited according to the range of motion of the human body, so that while the two-degree-of-freedom acromioclavicular and sternoclavicular joints are rotating, the origin of the three-degree-of-freedom glenohumeral ball-and-socket joint always coincides with the intersection point of the servo motor shafts of the second to fourth joints of the three degrees of freedom.
3. A non-orthogonal designed shoulder joint five degree of freedom isokinetic muscle strength evaluation and rehabilitation platform according to claim 1, characterized in that, For the active degrees of freedom of the two-degree-of-freedom acromioclavicular and sternoclavicular joints, the size of the second motor seat is designed specifically for different patients to ensure that the second motor seat and the human acromioclavicular part remain approximately relatively stationary when the two-degree-of-freedom acromioclavicular and sternoclavicular joints rotate.
4. The non-orthogonal design shoulder joint five-DOF isokinetic muscle strength assessment and rehabilitation platform as described in claim 1, characterized in that, The two-degree-of-freedom shoulder lock and chest lock joint also includes a base, a guide rail base, and two first motor base support ribs; the base is composed of alloy profiles, alloy profile corner brackets, and sliding nuts, and the two first motor base support ribs clamp the first motor bases with fasteners to ensure the stability of the upper structure of the first motor bases.
5. The non-orthogonal design shoulder joint five-DOF isokinetic muscle strength assessment and rehabilitation platform as described in claim 1, characterized in that, The bosses at the front end of the first to fourth reducers are all embedded in the holes of the corresponding first to fourth motor mounts to ensure concentricity and installation accuracy.
6. The non-orthogonal design shoulder joint five-DOF isokinetic muscle strength assessment and rehabilitation platform as described in claim 1, characterized in that, The first to fourth reducers use couplings for output. The fixed side and the deformable side of the coupling are connected by fasteners. The load is driven by friction through the clamping force on the output shaft of the reducer. At the same time, the fasteners are screwed into the output shaft of the reducer through the holes of the load to prevent axial movement of the coupling.
7. The non-orthogonal design shoulder joint five-DOF isokinetic muscle strength assessment and rehabilitation platform as described in claim 1, characterized in that, The upper arm fixing plate is equipped with straps for fixing the human body to the device. The upper arm fixing plate has straight slots at different positions for fixing the straps to accommodate different people. The position of the straps can be adjusted as needed to meet the needs of different people.