A passive shoulder exoskeleton robot for assisting overhead tasks and its design method

Abstract

The present invention relates to the technical field of exoskeleton robots, and relates to a passive shoulder exoskeleton robot for assisting overhead tasks and a design method. The exoskeleton includes a shoulder module, a passive drive module, a back support module, and a flexible module; the shoulder module includes a horizontal flexion and extension rod, a shoulder bending link, a sagittal flexion and extension rod, and a front and rear adjustment link; the passive drive module uses a torque generator for generating an assist torque, and its peak torque and peak torque angle are adjustable; the back support module includes a back slide rail, a waist fixing plate, an upper back rod, and a lower back rod; the flexible module includes a shoulder strap, a waist strap, and an arm binding. The design method includes: 1. Designing the shoulder module, with parameters including the pitch angle φ, the vertical distance d v and the horizontal deviation d b ; 2. Designing the passive drive module, with parameters including K, L i , α, β, r1, r2, r3, r; 3. Designing the back support module; 4. Designing the flexible module. It can achieve assistance to the human shoulder joint, reduce the human shoulder load, and reduce the risk of shoulder diseases.

Description

Technical Field

[0001] The present invention relates to the technical field of exoskeleton robots, and particularly to a passive shoulder exoskeleton robot for assisting overhead tasks and a design method thereof. Background Art

[0002] Work-related musculoskeletal disorders are the main cause of health problems for workers globally, affecting 1.71 billion people. This is closely related to the high demand in labor-intensive industries. It is statistically shown that workers on assembly lines need to raise their arms up to 4,600 times a day, and the incidence of shoulder musculoskeletal disorders is very high (accounting for 13%), resulting in long-term absenteeism (with an average median of 25 - 37 days), leading to decreased productivity and increased treatment costs. Overhead tasks have the greatest impact on shoulder injuries and are usually associated with high physical loads and awkward shoulder postures. Although factory automation technology seems to be a possible solution to reduce the burden on workers while maintaining productivity, it is costly and requires modification of the production line, making it difficult to be popularized to multiple tasks. In addition, for many complex tasks that require human flexibility and cognitive abilities, automated technology solutions do not provide effective support. Through research, it is found that the shoulder exoskeletons involved in current invention patents mainly focus on the rehabilitation field, and most of their structures are large and bulky, not suitable for assisting workers in performing overhead operations. Considering the low-cost characteristics of passive shoulder exoskeletons compared to active shoulder exoskeletons, they may be an economically effective tool in the future, which can assist in completing multiple overhead tasks while protecting workers from shoulder injuries.

[0003] Since the shoulder is one of the most complex joints in the human body, the insufficient kinematic compatibility between the exoskeleton and the user has become the main problem faced in the design process of current passive shoulder exoskeletons. Improving kinematic compatibility is crucial for users to accept the exoskeleton. At the same time, the shape of the assistive force curve of current passive shoulder exoskeletons is fixed, and the peak torque angle cannot be changed. Using the same shape of assistive force curve to adapt to multiple tasks and populations results in insufficient task adaptability and individual adaptability of the exoskeleton, and it is difficult to achieve the optimal assistive effect. Therefore, how to design a passive shoulder exoskeleton that can change the peak torque angle is crucial for improving the assistive efficiency and adaptability of the exoskeleton. Summary of the Invention

[0004] In view of the above problems, the present invention provides a passive shoulder exoskeleton robot for assisting overhead tasks and a design method thereof, which can assist the human shoulder joint, reduce the human shoulder load, and reduce the risk of shoulder musculoskeletal diseases.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A passive shoulder exoskeleton robot for assisting overhead tasks, comprising a shoulder module, a passive drive module, a back support module, and a flexible module; the shoulder module includes a horizontal flexion and extension rod 1, a shoulder bending link 2, a sagittal flexion and extension rod 3, and a front and rear adjustment link 12, and the shoulder module is used to increase the shoulder movement range when a person wears the exoskeleton; the passive drive module uses a torque generator 4 to generate an assisting torque, and the peak torque and peak torque angle of the assisting torque are adjustable; the back support module includes a back slide rail 5, a waist fixing plate 7, an upper back rod 11, and a lower back rod 9, and the back support module is used to support the overall structure of the exoskeleton; the flexible module includes shoulder straps 6, a waist belt 8, and arm bindings 10, and the flexible module is used to connect the exoskeleton to the human body.

[0007] One end of the shoulder bending link 2 and the front and rear adjustment link 12 are connected by the horizontal flexion and extension rod 1 to form a horizontal flexion and extension degree of freedom, with one on each side symmetric about the median sagittal plane of the human body; the other end of the shoulder bending link 2 and the torque generator 4 are connected by the sagittal flexion and extension rod 3 to form a sagittal flexion and extension degree of freedom, with one on each side; one end of the lower back rod 9 and the waist fixing plate 7 are connected to form a waist rotation degree of freedom, and its rotation axis is perpendicular to the sagittal plane, and the other end of the lower back rod 9 is connected to the back slide rail 5; one end of the upper back rod 11 is connected to the front and rear adjustment link 12, and the other end is connected to the back slide rail 5; the arm bindings 10 are fixed on the torque generator 4, with one on each side; the shoulder straps 6 are respectively connected to the back slide rail 5 and the waist belt 8; the waist belt 8 is respectively connected to the waist fixing plate 7 and the shoulder straps 6.

[0008] Further, the torque generator 4 is composed of a pulley block 13, a guide rail 14, a steel wire rope 15, a tensile elastic element 16, a figure-eight ring 17, a pre-tightening bolt 18, and a housing 19; the pulley block (13) includes a No. 1 pulley (131), a No. 2 pulley (132), a No. 3 pulley (133), a No. 4 pulley (134), and a No. 5 pulley (135);

[0009] The tensile elastic element 16 provides power as an energy storage element; one end of the steel wire rope 15 is fixed on the No. 1 pulley 131, wound around the No. 2 pulley 132 and the No. 3 pulley 133 in the middle, and connected to the tensile elastic element 16 through the middle of the No. 4 pulley 134 and the No. 5 pulley 135. The No. 4 pulley 134 and the No. 5 pulley 135 are placed side by side, and their function is to ensure that the direction of the steel wire rope 15 is in a straight line with the tensile elastic element 16; the No. 2 pulley 132 and the No. 3 pulley 133 are installed on the guide rail sliders that cooperate with the guide rail 14 and can slide along the guide rail 14; the other end of the tensile elastic element 16 is connected to the figure-eight ring 17, the other end of the figure-eight ring 17 is connected to the pre-tightening bolt 18, and the pre-tightening bolt 18 adjusts the pre-tightening length of the tensile elastic element 16; there is a rotation degree of freedom in the middle of the figure-eight ring 17, and its function is to ensure that the tensile elastic element 16 does not rotate when the pre-tightening bolt 18 is rotated; the housing 19 provides protection and support.

[0010] Further, the back slide rail 5 includes a back slide rail body 51, a back slider 52, and a back carbon fiber plate 53; the back slide rail body 51 is fixed on the back carbon fiber plate 53; there is a groove on the back slide rail body 51, and the back slider 52 is placed in the groove and can slide left and right in the back slide rail body 51;

[0011] The upper back rod 11 includes an upper part 111 of the upper back rod and a lower part 112 of the upper back rod; the upper end of the upper part 111 of the upper back rod is bolted to the end of the front and rear adjustment link 12, where there is a prefabricated threaded hole at the upper end of the upper part 111 of the upper back rod, and its installation position with the front and rear adjustment link 12 can be changed; the lower end of the upper part 111 of the upper back rod is bolted to the upper end of the lower part 112 of the upper back rod by using the length adjustment hole 20 to adjust the overall length of the upper back rod 11 of the exoskeleton; the lower end of the lower part 112 of the upper back rod is bolted to the back slider 52;

[0012] The lower back rod 9 includes an upper part 91 of the lower back rod and a lower part 92 of the lower back rod. The upper end of the upper part 91 of the lower back rod is fixedly connected to the back carbon fiber plate 53. The lower end of the upper part 91 of the lower back rod is bolted to the upper end of the lower part 92 of the lower back rod by using the length adjustment hole 20 to adjust the overall length of the lower back rod 9 of the exoskeleton; the lower end of the lower part 92 of the lower back rod is connected to the waist fixing plate 7 through a rotary joint.

[0013] Further, the size of the exoskeleton robot is adjustable. Among them, the front and rear adjustment link 12 can adjust its length to adapt to people with different back thicknesses, and the adaptable back thickness range is 5 - 10 cm; the upper back rod 11 and the lower back rod 9 can adjust their lengths to adapt to people with different back lengths, and the adaptable back length range is 43.6 - 66.6 cm; the upper back rod can slide left and right along the back slide rail 5 to adapt to people with different shoulder widths, and the adaptable shoulder width range is 29.6 - 45.6 cm; the arm bindings 10, the waist belt 8, and the shoulder straps 6 can adjust their lengths.

[0014] Further, the usage method of the exoskeleton robot is as follows: Before using the exoskeleton, the user can adjust the position of the No. 1 pulley 131 and the positions of the No. 2 pulley 132 and the No. 3 pulley 133 on the guide rail 14 according to the height of the over - head task actually faced and the requirement for the safety limit angle; during the use of the exoskeleton, the user adjusts the size of the exoskeleton through the arm bindings 10, the waist belt 8, the shoulder straps 6, the front and rear adjustment link 12, the upper back rod 11, the lower back rod 9, and the back slide rail 5 to make it conform to their own body size; after wearing, the peak torque of the torque generator 4 is changed by adjusting the pre - tightening bolt 18 to meet their own needs.

[0015] Based on the above technical solution, the present invention further provides a design method for a passive shoulder exoskeleton robot for assisting overhead tasks, which is used to design the above passive shoulder exoskeleton robot for assisting overhead tasks, and includes the following steps:

[0016] Step 1: Design the shoulder module. The design parameters of the shoulder module include the pitch angle φ, the vertical distance d v and the horizontal deviation d b ; among them, the pitch angle φ is the angle between the front and rear adjustment link and the human horizontal plane, and the vertical distance d v is defined as the vertical distance from the user's shoulder rotation center to the front and rear adjustment link, and the horizontal deviation d b is the horizontal distance between the user's shoulder rotation center and the exoskeleton shoulder rotation center; the pitch angle φ and the vertical distance d v are used to adjust the space between the acromion and the horizontal flexion and extension rod of the exoskeleton above it, and the horizontal deviation d b is used to adjust the deviation distance between the exoskeleton shoulder rotation center and the user's shoulder rotation center.

[0017] Step 2: Design the passive drive module. The passive drive module uses a torque generator. The design parameters of the torque generator include K, L i 、α、β、r 1 、r 2 、r 3 r, which are used to adjust the peak torque and the peak torque angle; among them, K is the stiffness of the tensile elastic element, and L i is the initial elongation of the tensile elastic element, α is the angle of the first pulley, β is the angle of the second pulley, and r 1 is the distance between the sagittal flexion and extension rod and the first pulley, r 2 is the distance between the sagittal flexion and extension rod and the guide rail, r 3 is the radius of the sagittal flexion and extension rod, and r is the radius of the first pulley, the second pulley, and the third pulley;

[0018] Step 3: Design the back support module to adapt to wearers of different body sizes;

[0019] Step 4: Design the flexible module to fix the exoskeleton on the human body.

[0020] Furthermore, in step 2, the design parameters of the torque generator include K, L i 、α、β、r 1 、r 2 、r 3 r, which are used to adjust the peak torque and the peak torque angle. Specifically: K, L i and r 1It mainly affects the peak torque of the assist torque curve. As the parameter increases, the peak torque increases; r 2 It affects the overall length of the torque generator housing; r 3 It mainly affects the assist torque in Stage 1, r 3 As it increases, the assist torque in Stage 1 increases, but the peak torque in Stage 2 remains basically unchanged; It has a slight influence on the peak torque of the assist torque curve and the demarcation angle between Stage 1 and Stage 2. An increase will cause a slight increase in the peak torque and a slight decrease in the demarcation angle value between Stage 1 and Stage 2; α and β mainly affect the peak torque of the assist torque curve, the peak torque angle, and the demarcation angle between Stage 1 and Stage 2. If α increases or β decreases, the peak torque of the assist torque curve decreases, the peak torque angle increases, and the demarcation angle between Stage 1 and Stage 2 increases;

[0021] The definitions of the above-mentioned Stage 1 and Stage 2 are as follows: According to whether the wire rope is in contact with the sagittal flexion and extension rod, the entire assist process can be divided into two stages: Stage 1 is the low-assist area, in which the wire rope is in contact with the sagittal flexion and extension rod and the force arm is very small; Stage 2 is the high-assist area, in which the wire rope is separated from the sagittal flexion and extension rod and the force arm first increases and then decreases.

[0022] Furthermore, in Step 2, the assist torque τ generated by the torque generator 4 exo , and the calculation method is:

[0023] τ exo =F s L exo (1)

[0024] In the formula, F s and L exo respectively represent the stored elastic potential energy and the force arm. The force arm is the vertical distance from the center of the exoskeleton sagittal flexion and extension rod to the wire rope between the No. 1 pulley and the No. 2 pulley. F s is obtained through formula (2)

[0025] F s =KΔL (2)

[0026] where K is the stiffness of the tensile elastic element and ΔL is the tensile amount of the tensile elastic element.

[0027] Furthermore, the calculation formula for the tensile amount ΔL of the tensile elastic element is:

[0028] ΔL=ΔL(θ sexo )=L A′B′ (θ s，exo )-L A′B′ (max(θ s,exo ))+L i (3)

[0029] where L A′B′ is the change in the length of the wire rope between the first pulley and the third pulley. When θ s，exo reaches its maximum value, L A′B′ is at its shortest length, and L i is the initial elongation of the tensile elastic element.

[0030] Compared with the prior art, the present invention has the following beneficial technical effects:

[0031] 1. A shoulder structure is designed to simultaneously meet the sagittal flexion / extension and horizontal flexion / extension movement ranges of the human shoulder, addressing the difficulty of achieving good human-machine compatible kinematic performance in existing rigid upper limb exoskeletons.

[0032] 2. A torque generator is designed to change the peak torque angle to address the problem that existing passive upper limb exoskeletons cannot change the peak torque angle. This torque generator can reconstruct the assist curve at two levels: the peak and phase of the assist torque curve, improving the assist effect of the exoskeleton.

[0033] 3. The present invention can effectively assist the shoulder during overhead tasks, reducing the physical burden on the shoulder, decreasing related muscle activation, thereby delaying muscle fatigue and reducing the risk of musculoskeletal diseases. Performance verification experiments of the present invention show that, in the case of exoskeleton matching, the relative percentage decrease in muscle activation can reach approximately 40%.

[0034] 4. Compared with active exoskeletons, the passive shoulder exoskeleton in the present invention has low cost and good economy.

[0035] 5. The passive shoulder exoskeleton in the present invention also has the characteristics of light weight, convenient use, and comfortable wearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a schematic diagram of the overall structure of the exoskeleton;

[0037] Figure 2 is a diagram defining the design parameters of the shoulder structure of the exoskeleton,

[0038] wherein, Figure 2 (a) is the perspective view of the ψ plane, Figure 2 (b) is the top view perspective;

[0039] Figure 3 is a schematic diagram of the kinematic models of the user and the exoskeleton,

[0040] wherein, Figure 3 (a) is the kinematic model of the user, Figure 3 (b) is the kinematic model of the exoskeleton;

[0041] Figure 4 It is a simulation result diagram of the range of motion of the shoulder structure;

[0042] Figure 5 It is a schematic diagram of the overall structure of the torque generator;

[0043] Figure 6 It is a schematic diagram of the force arm of the torque generator;

[0044] Figure 7 It is a schematic diagram of the assist curve of the torque generator;

[0045] Figure 8 It is a schematic diagram of the design parameters of the torque generator;

[0046] Among them Figure 8 (a) is a schematic diagram of the design parameters in Stage 1, Figure 8 (b) is a schematic diagram of the design parameters in Stage 2;

[0047] Figure 9 It is a diagram showing the relationship between the peak torque angle and β in the torque generator;

[0048] Figure 10 It is a simulation auxiliary torque curve diagram of the torque generator, where,

[0049] Figure 10 (a) is the influence diagram of L i on the auxiliary torque curve, Figure 10 (b) is the influence diagram of r 1 on the auxiliary torque curve,

[0050] Figure 10 (c) is the influence diagram of r 2 on the auxiliary torque curve, Figure 10 (d) is the influence diagram of r 3 on the auxiliary torque curve,

[0051] Figure 10 (e) is the influence diagram of α on the auxiliary torque curve, Figure 10 (f) is the influence diagram of β on the auxiliary torque curve,

[0052] Figure 10 (g) is the influence diagram of r on the auxiliary torque curve; Figure 10 (h) is the influence diagram of K on the auxiliary torque curve;

[0053] Figure 11 It is a schematic diagram of the exoskeleton experiment task,

[0054] Among them Figure 11 (a) corresponds to the range of motion experiment, Figure 11 (b) corresponds to the performance verification experiment;

[0055] Figure 12 is a highly defined diagram of the exoskeleton performance verification experiment;

[0056] Figure 13 is the muscle activation diagram of the exoskeleton performance verification experiment,

[0057] wherein Figure 13 (a) corresponds to screwing a screw at a low height, Figure 13 (b) corresponds to screwing a screw at a high height.

[0058] Reference numerals:

[0059] 1. Horizontal flexion and extension rod; 2. Shoulder bending link; 3. Sagittal flexion and extension rod; 4. Torque generator;

[0060] 5. Back slide rail, 51. Back slide rail body, 52. Back slider, 53. Back carbon fiber plate;

[0061] 6. Shoulder strap; 7. Lumbar fixing plate; 8. Belt;

[0062] 9. Lower back rod, 91. Upper part of the lower back rod, 92. Lower part of the lower back rod; 10. Arm binding;

[0063] 11. Upper back rod, 111. Upper part of the upper back rod, 112. Lower part of the upper back rod;

[0064] 13. Pulley block, 131. No. 1 pulley, 132. No. 2 pulley, 133. No. 3 pulley,

[0065] 134. No. 4 pulley, 135. No. 5 pulley;

[0066] 14. Guide rail; 15. Steel wire rope; 16. Tensile elastic element; 17. Figure-eight ring;

[0067] 18. Pre-tightening bolt; 19. Outer shell; 20. Length adjustment hole. Detailed implementation manners

[0068] To make the objectives, technical solutions and advantages of the present invention clearer, the following describes the embodiments of the present invention in detail with reference to the accompanying drawings.

[0069] The present invention provides a passive shoulder exoskeleton robot for assisting in over-head tasks, as Figure 1As shown in the figure, it includes a shoulder module, a passive drive module, a back support module, and a flexible module; the shoulder module includes a horizontal flexion and extension rod 1, a shoulder bending link 2, a sagittal flexion and extension rod 3, and a front-back adjustment link 12, and the shoulder module is used to increase the shoulder movement range when a person wears the exoskeleton; the passive drive module uses a torque generator 4 to generate an assist torque, and the peak torque and peak torque angle of the assist torque are adjustable; the back support module includes a back slide rail 5, a waist fixing plate 7, an upper back rod 11, and a lower back rod 9, and the back support module is used to support the overall structure of the exoskeleton; the flexible module includes shoulder straps 6, a waist belt 8, and arm bindings 10, and the flexible module is used to connect the exoskeleton to the human body.

[0070] This exoskeleton robot has a total of 5 degrees of freedom. One end of the shoulder bending link 2 and the front-back adjustment link 12 are connected by the horizontal flexion and extension rod 1 to form a horizontal flexion and extension degree of freedom, with one on each side with the median sagittal plane of the human body as the symmetry plane; the other end of the shoulder bending link 2 and the torque generator 4 are connected by the sagittal flexion and extension rod 3 to form a sagittal flexion and extension degree of freedom, with one on each side; one end of the lower back rod 9 is connected to the waist fixing plate 7 to form a waist rotation degree of freedom, and its rotation axis is perpendicular to the sagittal plane. The other end of the lower back rod 9 is connected to the back slide rail 5; one end of the upper back rod 11 is connected to the front-back adjustment link 12, and the other end is connected to the back slide rail 5; the arm bindings 10 are fixed on the torque generator 4, with one on each side; the shoulder straps 6 are respectively connected to the back slide rail 5 and the waist belt 8; the waist belt 8 is respectively connected to the waist fixing plate 7 and the shoulder straps 6.

[0071] The following will separately explain the four modules:

[0072] I. Shoulder module

[0073] (1) Overall introduction of the shoulder module

[0074] As one of the most complex joints in the human body, the shoulder has the characteristic of flexible movement. In order to ensure that the normal movement range of a person is not affected when wearing the shoulder exoskeleton, an ergonomic shoulder structure needs to be designed. The center of the glenohumeral joint is considered to be the center of the shoulder of the user (CSU). The intersection of the rotation axes of the sagittal flexion and extension rod 3 and the horizontal flexion and extension rod 1 is considered to be the center of the shoulder of the exoskeleton (CSE). The center of the shoulder of the exoskeleton is close to the center of the shoulder of the user, which enables the torque generator 4 to better track the shoulder movement. However, the positions of the two do not coincide, and the shoulder movement is accompanied by the elevation and posterior displacement of the humerus, resulting in the deviation of the center of the shoulder of the user. Therefore, it is necessary to extract the structural design parameters and find the optimal solution. For this purpose, the present invention defines the following structural design parameters: pitch angle φ, vertical distance dv and the horizontal deviation d b , as Figure 2 shown. Define the plane that contains the front and rear adjustment link 12 and is perpendicular to the human body's horizontal plane as the ψ plane. The pitch angle φ is the angle between the front and rear adjustment link 12 and the human body's horizontal plane; the vertical distance d v is defined as the vertical distance between the rotation center of the user's shoulder and the front and rear adjustment link 12; the horizontal deviation d b is the horizontal distance between the rotation center of the user's shoulder and the rotation center of the exoskeleton's shoulder. Φ and d v can define the configuration of the front and rear adjustment link 12, and d b can be adjusted by the front and rear adjustment link 12. Increasing Φ and d v can expand the space between the user and the exoskeleton's shoulder, which is used for the elevation of the humerus to avoid the collision between the exoskeleton and the user at high elevation angles. Increasing d b can move the rotation center of the exoskeleton's shoulder backward towards the user's shoulder to compensate for the displacement of the rotation center of the user's shoulder during the movement of the user's shoulder.

[0075] (II) Shoulder kinematic modeling and analysis of design parameters

[0076] To better explore the influence of shoulder design parameters on the range of motion, kinematic analysis needs to be carried out. Here, only consider two degrees of freedom of the user, namely the horizontal flexion-extension degree of freedom and the sagittal flexion-extension degree of freedom, which are represented by θ h，user and θ s，user respectively, representing the human body's horizontal flexion-extension angle and sagittal flexion-extension angle. Correspondingly, the horizontal flexion-extension degree of freedom and the sagittal flexion-extension degree of freedom of the exoskeleton are represented by θ h，exo and θ s，exo respectively, representing the exoskeleton's horizontal flexion-extension angle and sagittal flexion-extension angle. D user and D exo represent the distances from the rotation center of the user's shoulder and the rotation center of the exoskeleton's shoulder to the centroid of the arm restraint 10 respectively, Figure 3 is the kinematic model diagram of the user and the exoskeleton established. Table 1 and Table 2 are the Denavit-Hartenberg (DH) parameters of the user's kinematic model and the exoskeleton's kinematic model respectively. The connection between these two models is that their coordinate origins are both the rotation center of the user's shoulder, and the arm restraint 10 is in the same position. Using this characteristic, carry out simulation calculations for the shoulder range of motion when the user wears the exoskeleton. The specific simulation process is shown in Table 3. Figure 4 Shows the selected seven groups of design parameters and the corresponding range of motion.

[0077] Table 1. DH parameters of the user's kinematic model

[0078]

[0079] In Table 1, α i-1 is the angle along the x i axis, rotating from z i to z i+1 ; a i-1 is the distance along the x i axis, moving from z i to z i+1 ; d i is the distance along the z i axis, moving from x i-1 to x i ; θ i is the angle along the z i axis, rotating from x i-1 to x i .

[0080] Table 2. DH Parameters of the Exoskeleton Kinematic Model

[0081]

[0082] Table 3. Simulation of the Range of Motion When the User Wears the Exoskeleton

[0083]

[0084] In Table 3, (p x , p y , p z ) respectively represent the x-axis coordinate, y-axis coordinate, and z-axis coordinate of the centroid of the arm binding.

[0085] II. Passive Driving Module

[0086] (I). Overall Introduction of the Torque Generator

[0087] The passive driving module adopts a torque generator. As Figure 5 shown, the torque generator 4 consists of a pulley block 13, a guide rail 14, a wire rope 15, a tensile elastic element 16, a figure-eight ring 17, a pre-tightening bolt 18, and a housing 19. The pulley block 13 includes a pulley 131, a pulley 132, a pulley 133, a pulley 134, and a pulley 135; among them, the radii of the pulley 131, the pulley 132, and the pulley 133 are the same.

[0088] The stretching elastic element 16 provides power as an energy storage element; one end of the steel wire rope 15 is fixed on the pulley 131 of No. 1, wound around the pulley 132 of No. 2 and the pulley 133 of No. 3 in the middle, and is connected to the stretching elastic element 16 through the middle of the pulley 134 of No. 4 and the pulley 135 of No. 5. Among them, the pulley 134 of No. 4 and the pulley 135 of No. 5 are placed side by side, and their function is to ensure that the direction of the steel wire rope 15 is in a straight line with the stretching elastic element 16; the pulley 132 of No. 2 and the pulley 133 of No. 3 are installed on the guide rail slider that cooperates with the guide rail 14 and can slide along the guide rail 14; the other end of the stretching elastic element 16 is connected to the figure-eight ring 17, and the other end of the figure-eight ring 17 is connected to the pre-tightening bolt 18. The pre-tightening bolt 18 can adjust the pre-tightening length of the stretching elastic element 16. There is a rotational degree of freedom in the middle of the figure-eight ring 17, and its function is to ensure that the stretching elastic element 16 does not rotate when the pre-tightening bolt 18 is rotated; the housing 19 provides protection and support.

[0089] Among them, the stretching elastic element 16 is one of a parallel spring group, an elastic rope, and a tension spring.

[0090] Since the torque generator 4 is fixed to the user's upper arm by the arm binding 10, it can be assumed that the flexion and extension angles of the exoskeleton and the user are the same. The assisting principle of the torque generator 4 is to store the elastic potential energy of the stretching elastic element 16 when the arm is lowered and release the elastic potential energy of the stretching elastic element 16 when the arm is lifted. Its characteristic is that both the peak torque of the assisting torque and the peak assistive torque angle (PATA) can be adjusted.

[0091] (2) Description of the assisting torque

[0092] The assisting torque τ generated by the torque generator 4 exo , and the calculation method is:

[0093] τ exo =F s L exo (1)

[0094] In the formula, F s and L exo respectively represent the stored elastic potential energy and the force arm. The force arm is the vertical distance from the center of the sagittal flexion and extension rod 3 of the exoskeleton to the steel wire rope between the pulley 131 of No. 1 and the pulley 132 of No. 2. As Figure 6 shown, F s can be obtained through formula (2)

[0095] F s =KΔL (2)

[0096] Where K is the stiffness of the tensile elastic element 16, and ΔL is the elongation of the tensile elastic element 16. During shoulder movement, since the wire rope 15 is in series with the tensile elastic element 16, the elongation of the tensile elastic element 16 is the same as the change in the length of the wire rope 15 between pulley 1 and pulley 3 (i.e., Figure 8 the length of the wire rope between the midpoint A' and point B'). ΔL can be constructed as a function of the sagittal flexion / extension angle (θ s，exo ),

[0097] ΔL = ΔL(θ s,exo ) = L A′B′ (θ s，exo ) - L A′B′ (max(θ s,exo )) + L i (3)

[0098] Where L A′B′ is the change in the length of the wire rope between pulley 1 and pulley 3. When θ s，exo reaches its maximum value, the length of L A′B′ is the shortest at this time. L i is the initial elongation of the tensile elastic element 16 and can be adjusted by the pre-tightening bolt 18.

[0099] Figure 7 Shows the change in the force arm and the torque curve. The gray part in the figure represents stage 1, and the white part represents stage 2. It can be seen that the change process of the force arm L exo first increases and then decreases, while the elongation ΔL of the tensile elastic element 16 is monotonically decreasing. Therefore, it can be known that the force arm L exo will affect the peak torque angle of the assist torque, and ΔL affects the peak torque.

[0100] To better identify the assist torque curve, six design parameters (α, β, r 1 , r 2 , r 3 , r) are extracted, and their meanings are shown in Table 4.

[0101] Table 4. Definition of the design parameters of the torque generator

[0102]

[0103] The main parameters affecting L exo are α and β. When α increases or β decreases, the peak angle of L exo will shift to the left, which causes the peak torque angle of the assist curve to also shift to the left accordingly. To explore the change trend of the peak torque angle, when α = β = 0, the peak torque angle at this time is defined as the reference value, represented by θ 0 . The peak torque angle (θPATA ) It can be expressed by formulas (4)-(5):

[0104] θ PATA = θ 0 + α - kβ (4)

[0105]

[0106] where r is the radius of the second pulley 132, and r 2 is the distance between the sagittal flexion / extension rod and the guide rail; due to the non-linear influence of ΔL on τ exo , k is a variable positive value close to 1. It can be seen from formulas (4)-(5) that increasing r or decreasing r 2 can make θ 0 decrease, and then lead to a decrease in the peak torque angle. It can be seen from the simulation experiment results that this influence is very weak. Refer to Figure 10 (c) and Figure 10 (g). In order to make the peak torque angle adjustable to adapt to different tasks and populations, β can be adjusted by changing the positions of the second pulley 132 and the third pulley 133 on the guide rail 14. The relationship between the peak torque angle and β is as Figure 9 shown.

[0107] (III) Analyze the influence of parameters on the torque curve by stages

[0108] According to whether the steel wire rope 15 is in contact with the sagittal flexion / extension rod 3, the entire assistance process can be divided into two stages: Stage 1 is the low assistance area, corresponding to Figure 8 (a). In this stage, since the steel wire rope 15 is in contact with the sagittal flexion / extension rod 3, the force arm is very small, so the assistance torque is low to prevent hindering the normal movement of the user; Stage 2 is the high assistance area, corresponding to Figure 8 (b). In this stage, since the steel wire rope 15 is separated from the sagittal flexion / extension rod 3, the force arm first increases and then decreases, resulting in the torque first increasing and then decreasing. The contact between the steel wire rope 15 and the sagittal flexion / extension rod 3 can ensure that the assistance torque is always a positive effect. If the steel wire rope 15 does not rest on the sagittal flexion / extension rod 3 at a low angle, it will cause a negative torque, stretching the arm backward and creating a safety hazard.

[0109] Define the shoulder flexion / extension angle corresponding to the critical state of Stage 1 and Stage 2 as θ c , and its magnitude is related to α and β. When α increases or β decreases, θ c will become larger. The influence of each parameter on the assistance torque will be introduced by stages below. Figure 9 are the simulation experiment results of the influence of each design parameter on the assistance torque. It should be noted that no matter in which stage, the stiffness K and the initial stretching amount L of the tensile elastic element 16 iAll are positively correlated with the peak torque and independent of the peak torque angle.

[0110] Stage 1: The parameter that affects the assist torque in this stage is mainly the radius r of the sagittal flexion and extension rod 3. 3 . When r 3 increases, L A′B′ and L exo increase, which causes the assist torque in the low-assist area to become larger.

[0111] Stage 2: The parameters that affect the assist torque in this stage are mainly the angle α of the first pulley 131, the angle β of the second pulley 132, and the distance r between the sagittal flexion and extension rod 3 and the first pulley 131. 1 . When r 1 increases, L A′B′ and L exo increase, thereby causing the peak torque to become larger. When α increases or β decreases, the peak angle of L exo will shift to the left, which causes the peak torque angle of the assist curve to also shift to the left accordingly. α also has a limiting function, and different positions correspond to different maximum flexion and extension angles, with a maximum of 170° and a minimum of 140°. At the same time, r 2 and r were tested, and it was found that they basically do not affect the peak torque and the peak torque angle.

[0112] III. Back support module

[0113] As Figure 1 shown, the back support module includes a back slide rail 5, a waist fixing plate 7, an upper back rod 11, and a lower back rod 9.

[0114] The back slide rail 5 includes a back slide rail body 51, a back slider 52, and a back carbon fiber plate 53; the back slide rail body 51 is fixed on the back carbon fiber plate 53; there is a groove on the back slide rail body 51, and the back slider 52 is placed in the groove and can slide left and right in the back slide rail body 51.

[0115] The upper back rod 11 includes an upper part 111 of the upper back rod and a lower part 112 of the upper back rod. The upper end of the upper part 111 of the upper back rod is connected to the end of the front and rear adjustment link 12 by a bolt. There are prefabricated threaded holes at the upper end of the upper part 111 of the upper back rod, and its installation position with the front and rear adjustment link 12 can be changed. The lower end of the upper part 111 of the upper back rod is connected to the upper end of the lower part 112 of the upper back rod by a bolt using the length adjustment hole 20 to adjust the overall length of the upper back rod 11 of the exoskeleton. The lower end of the lower part 112 of the upper back rod is connected to the back slider 52 by a bolt.

[0116] The lower back rod 9 includes an upper part 91 of the lower back rod and a lower part 92 of the lower back rod. The upper end of the upper part 91 of the lower back rod is fixedly connected to the back carbon fiber plate 53. The lower end of the upper part 91 of the lower back rod and the upper end of the lower part 92 of the lower back rod are connected by bolts using the length adjustment hole 20 to adjust the overall length of the exoskeleton lower back rod 9. The length adjustment hole 20 for adjusting the lower back rod 11 is on the side. The lower end of the lower part 92 of the lower back rod is connected to the waist fixing plate 7 through a rotary joint, making the exoskeleton fit the human movement better.

[0117] IV. Flexible Module

[0118] The flexible module includes a shoulder strap 6, a waist strap 8, and an arm binding 10. The shoulder strap 6 and the waist strap 8 are used to fix the exoskeleton structure to the human body, and the lengths of the shoulder strap 6 and the waist strap 8 are both adjustable. The arm binding 10 is used to connect the torque generator 4 to the human arm to achieve the effect that the torque generator 4 follows the movement of the human arm; the arm binding 10 can be made by 3D printing, and the material is resin or nylon.

[0119] The size of the exoskeleton robot of the present invention is adjustable to adapt to people with different body types. The front and rear adjustment link 12 can adjust its length to adapt to people with different back thicknesses (i.e., the thickness of the body from front to back), and the adaptable back thickness range is 5 - 10 cm; the upper back rod 11 and the lower back rod 9 can adjust their lengths to adapt to people with different back lengths (i.e., the length of the upper body of the body), and the adaptable back length range is 43.6 - 66.6 cm; the upper back rod can slide left and right along the back slide rail 5 to adapt to people with different shoulder widths, and the adaptable shoulder width range is 29.6 - 45.6 cm; the flexible module (arm binding 10, waist strap 8, and shoulder strap 6) can adjust its length to adapt to people with different body types and ensure comfortable wearing.

[0120] The usage method of the exoskeleton robot is as follows: Before using the exoskeleton, the user can adjust the position of the No. 1 pulley 131 and the positions of the No. 2 pulley 132 and the No. 3 pulley 133 on the guide rail 14 according to the actual over - head task height faced and the requirements for the safety limit angle. During the use of the exoskeleton, the user can adjust the size of the exoskeleton through the arm binding 10, the waist strap 8, the shoulder strap 6, the front and rear adjustment link 12, the upper back rod 11, the lower back rod 9, and the back slide rail 5 to make it conform to their own body size. After wearing, the peak torque of the torque generator 4 can be changed by adjusting the pre - tightening bolt 18 to meet their own needs.

[0121] Based on the above technical solutions, the present invention also provides a design method for a passive shoulder exoskeleton robot for assisting over - head tasks, including the following steps:

[0122] Step 1: Design the shoulder module. The design parameters of the shoulder module include the pitch angle φ, the vertical distance d v and the horizontal deviation d b ;

[0123] Among them, the pitch angle φ is the angle between the front-back adjustment link and the human body horizontal plane, and the vertical distance d v is defined as the vertical distance from the rotation center of the user's shoulder to the front-back adjustment link, and the horizontal deviation d b is the horizontal distance between the rotation center of the user's shoulder and the rotation center of the exoskeleton shoulder; the pitch angle φ and the vertical distance d v are used to adjust the space between the acromion and the horizontal flexion-extension rod of the exoskeleton above it, and the horizontal deviation d b is used to adjust the deviation distance between the rotation center of the exoskeleton shoulder and the rotation center of the user's shoulder.

[0124] Step 2: Design the passive drive module. The passive drive module adopts a torque generator. The design parameters of the torque generator include K, L i , α, β, r 1 , r 2 , r 3 r, which is used to adjust the peak torque and the peak torque angle; among them, K is the stiffness of the tensile elastic element, and L i is the initial elongation of the tensile elastic element, α is the angle of the No. 1 pulley, β is the angle of the No. 2 pulley, and r 1 is the distance between the sagittal flexion-extension rod and the No. 1 pulley, r 2 is the distance between the sagittal flexion-extension rod and the guide rail, r 3 is the radius of the sagittal flexion-extension rod, and r is the radius of the No. 1 pulley, No. 2 pulley and No. 3 pulley.

[0125] The influence of the above design parameters on the auxiliary torque curve is as Figure 10 shown. K, L i and r 1 mainly affect the peak torque of the assisting torque curve. As the parameters increase, the peak torque increases; r 2 has basically no influence on the assisting torque curve, but since r 2 is the distance between the sagittal flexion-extension rod and the guide rail, so r 2 affects the overall length of the torque generator housing; r 3 mainly affects the assisting torque in stage 1. When r 3 increases, the assisting torque in stage 1 increases, but the peak torque in stage 2 remains basically unchanged; r has a slight influence on the peak torque of the assisting torque curve and the demarcation angle between stage 1 and stage 2. When r increases, the peak torque will increase slightly and the demarcation angle value between stage 1 and stage 2 will decrease slightly; α and β mainly affect the peak torque, the peak torque angle and the demarcation angle between stage 1 and stage 2 of the assisting torque curve. If α increases or β decreases, the peak torque of the assisting torque curve decreases, the peak torque angle increases, and the demarcation angle between stage 1 and stage 2 increases.

[0126] Among the above parameters, r 1 , r 2 , r 3 and r are parameters that need to be determined during the design phase. Once determined and the exoskeleton entity is constructed, these parameters cannot be changed anymore, unless the exoskeleton is reconstructed; but L i , K, α, and β can still be changed after the exoskeleton is constructed. Among them, L i can be adjusted by pre-tightening bolts, K can be adjusted by replacing elastic elements, α can be adjusted by changing the installation position of pulley No. 1 (there are prefabricated installation holes at the end of the shoulder bending link, as Figure 9 shown), and β can be adjusted by changing the positions of pulley No. 2 and pulley No. 3 on the slide rail.

[0127] Step 3: Design the back support module to adapt to wearers of different body sizes.

[0128] Step 4: Design the flexible module to fix the exoskeleton on the human body.

[0129] Example:

[0130] A passive shoulder exoskeleton robot for assisting in over-head tasks includes a shoulder module, a passive drive module, a back support module, and a flexible module; the shoulder module includes a horizontal flexion and extension rod 1, a shoulder bending link 2, a sagittal flexion and extension rod 3, and a front and rear adjustment link 12, which are used to increase the shoulder movement range when a person wears the exoskeleton; the passive drive module uses a torque generator 4 to generate an assisting torque, and the peak torque and peak torque angle of the assisting torque are adjustable; the back support module includes a back slide rail 5, a waist fixing plate 7, an upper back rod 11, and a lower back rod 9, which are used to support the overall structure of the exoskeleton; the flexible module includes shoulder straps 6, a waist belt 8, and arm bindings 10, which are used to connect the exoskeleton to the human body.

[0131] This exoskeleton robot has a total of 5 degrees of freedom. One end of the shoulder bending link 2 and the front and rear adjustment link 12 are connected by the horizontal flexion and extension rod 1 to form a horizontal flexion and extension degree of freedom, with one on each side with the median sagittal plane of the human body as the symmetry plane; the other end of the shoulder bending link 2 and the torque generator 4 are connected by the sagittal flexion and extension rod 3 to form a sagittal flexion and extension degree of freedom, with one on each side; one end of the lower back rod 9 is connected to the waist fixing plate 7 to form a waist rotation degree of freedom, and its rotation axis is perpendicular to the sagittal plane. The other end of the lower back rod 9 is connected to the back slide rail 5; one end of the upper back rod 11 is connected to the front and rear adjustment link 12, and the other end is connected to the back slide rail 5; the arm bindings 10 are fixed on the torque generator 4, with one on each side; the shoulder straps 6 are respectively connected to the back slide rail 5 and the waist belt 8; the waist belt 8 is respectively connected to the waist fixing plate 7 and the shoulder straps 6.

[0132] The shoulder module includes the pitch angle φ and the vertical distance d vand the horizontal deviation d b Three design parameters. In this embodiment, the specific design parameters are φ = 15°, d v = 80 mm, d b = 10 mm. The movement range obtained by this set has ensured that while the user can move normally, they can complete the over-head task.

[0133] The passive drive module adopts a torque generator. The torque generator 4 is composed of a pulley group 13, a guide rail 14, a wire rope 15, a tensile elastic element 16, a figure-eight ring 17, a pre-tightening bolt 18, and a housing 19. The pulley group 13 includes a pulley 131, a pulley 132, a pulley 133, a pulley 134, and a pulley 135; in this embodiment, the pulley 131, the pulley 132, and the pulley 133, the pulley 134, and the pulley 135 use pulleys with the same radius.

[0134] In this embodiment, the tensile elastic element 16 adopts a parallel spring group; one end of the wire rope 15 is fixed on the pulley 131, wound around the pulley 132 and the pulley 133 in the middle, and connected to the parallel spring group through the middle of the pulley 134 and the pulley 135. The pulley 134 and the pulley 135 are placed side by side to ensure that the wire rope 15 is in a straight line with the parallel spring group; the pulley 132 and the pulley 133 are installed on the guide rail slider that cooperates with the guide rail 14 and can slide along the guide rail 14; the other end of the parallel spring group is connected to the figure-eight ring 17, the other end of the figure-eight ring 17 is connected to the pre-tightening bolt 18, and the pre-tightening bolt 18 can adjust the pre-tightening length of the parallel spring group. The figure-eight ring 17 contains a rotational degree of freedom in the middle, and its function is to ensure that the parallel spring group does not rotate when the pre-tightening bolt 18 is rotated; the housing 19 provides protection and support.

[0135] The design parameters of the torque generator include K, L i 、α、β、r 1 、r 2 、r 3 r, which are used to adjust the peak torque and the peak torque angle. The specific design parameter values of the torque generator in this embodiment are shown in the following table.

[0136] Table 5 Numerical Table of Torque Generator Design Parameters

[0137]

[0138]

[0139] The back support module includes a back slide rail 5, a waist fixing plate 7, an upper back rod 11, and a lower back rod 9.

[0140] The back slide rail 5 includes a back slide rail body 51, a back slider 52, and a back carbon fiber plate 53; the back slide rail body 51 is fixed on the back carbon fiber plate 53; there is a groove on the back slide rail body 51, and the back slider 52 is placed in the groove and can slide left and right in the back slide rail body 51.

[0141] The upper back rod 11 includes an upper part 111 of the upper back rod and a lower part 112 of the upper back rod. The upper end of the upper part 111 of the upper back rod is connected to the end of the front and rear adjustment link 12 by a bolt. There is a prefabricated threaded hole at the upper end of the upper part 111 of the upper back rod, and its installation position with the front and rear adjustment link 12 can be changed. The lower end of the upper part 111 of the upper back rod is connected to the upper end of the lower part 112 of the upper back rod by a bolt using the length adjustment hole 20, so as to adjust the overall length of the upper back rod 11 of the exoskeleton. The lower end of the lower part 112 of the upper back rod is connected to the back slider 52 by a bolt.

[0142] The lower back rod 9 includes an upper part 91 of the lower back rod and a lower part 92 of the lower back rod. The upper end of the upper part 91 of the lower back rod is fixedly connected to the back carbon fiber plate 53. The lower end of the upper part 91 of the lower back rod is connected to the upper end of the lower part 92 of the lower back rod by a bolt using the length adjustment hole 20, so as to adjust the overall length of the lower back rod 9 of the exoskeleton. The length adjustment hole 20 for adjusting the lower back rod 11 is on the side. The lower end of the lower part 92 of the lower back rod is connected to the waist fixing plate 7 through a rotary joint.

[0143] The flexible module includes a shoulder strap 6, a waist belt 8, and an arm binding 10. The lengths of the shoulder strap 6 and the waist belt 8 are both adjustable. The arm binding 10 is used to connect the torque generator 4 to the human arm. The arm binding 10 can be made by 3D printing, and the material is resin. Performance verification:

[0144] To further verify the rationality of the present invention, a range of motion experiment and a performance verification experiment are carried out.

[0145] 1. Experimental content

[0146] Five healthy males participated in the range of motion experiment (age ± standard deviation: 24.1 ± 1.64 years old, height ± standard deviation: 173.8 ± 3.27 cm, weight ± standard deviation: 70 ± 9.06 kg). Each experimental subject was required to perform horizontal flexion and extension and sagittal flexion and extension movements at a suitable speed selected by himself to the maximum extent, and each movement was performed 5 times. The experimental configuration for each person included two cases: wearing and not wearing the exoskeleton. The data of the range of motion experiment were collected by optical motion capture (sampling frequency 100 Hz, VICON, UK).

[0147] The performance verification experiment involved 10 healthy males (age ± standard deviation: 25.1 ± 2.0 years, height ± standard deviation: 177 ± 4.3 cm, weight ± standard deviation: 68.3 ± 9.3 kg). Each subject was required to perform a screw - tightening task at two working heights on an adjustable - height aluminum alloy frame. The low height was defined as the hand height when the shoulder was elevated by 90°, and the high height was defined as the hand height when the shoulder was elevated by 120°. The exoskeleton configurations were divided into two types: one with a peak torque angle of 90° and the other with a peak torque angle of 120°. It should be noted that only two peak torque angles were adopted as the experimental configurations of the exoskeleton in this experiment. In reality, the exoskeleton can achieve any peak torque angle configuration between 90° and 150°. When the peak torque angle of the exoskeleton matches the shoulder elevation angle, the experimental configuration is defined as exoskeleton - matched; otherwise, it is exoskeleton - unmatched. In summary, there are two task heights, namely low height and high height, and three experimental configurations, namely not wearing an exoskeleton, exoskeleton - matched, and exoskeleton - unmatched. Each subject needed to perform six experiments, and each experiment lasted for 2 minutes. The task height and experimental configuration were randomly assigned. The experimental procedure is shown in the following figure. The data collected in the performance verification experiment included electromyography (EMG) data and inertial measurement unit (IMU) data (hereinafter referred to as IMU data). Among them, the EMG data was used to evaluate the exoskeleton performance, with a sampling frequency of 1111 Hz, and the IMU data was used to divide the task intervals of the data, with a sampling frequency of 148 Hz. The EMG was collected from the muscles on the right side of the human body, specifically at the anterior deltoid (AD), middle deltoid (MD), posterior deltoid (PD), biceps brachii (BB), pectoralis major (PM), trapezius (TR), latissimus dorsi (LD), and erector spinae (ES). The IMU data was resampled to 1111 Hz, and then the acceleration variance was calculated through a 30 - ms non - overlapping sliding time window. The mean of the variance plus twice the standard deviation was selected as the threshold to divide the motion intervals. The EMG data within the motion intervals was pre - processed to obtain the envelope, including zero - mean, band - pass filtering (4th order, 20 - 350 Hz), full - wave rectification, low - pass filtering (6 Hz), and normalization. For the two tasks of screw - tightening at high and low heights, the maximum amplitude of each muscle without wearing an exoskeleton for each subject was used to normalize the EMG data. The root - mean - square of the envelope of each muscle for each subject was calculated using a 30 - ms non - overlapping sliding time window. Statistical analysis was performed on the experimental results. The Shapiro - Wilk test was used to test the normality of the data. If the data did not meet the normal distribution, non - parametric analysis of variance (ANOVA) was performed to check for differences across conditions; otherwise, parametric ANOVA was applied. When a significant effect was observed, a post - hoc analysis was conducted. When the significance p - value was less than 0.05, a statistically significant conclusion was drawn.

[0148] 2. Experimental Results

[0149] (1) Range - of - motion experiment

[0150] Based on the data collected by VICON, the maximum sagittal flexion / extension angle and the maximum horizontal flexion / extension angle for each person under each experimental configuration were processed, and the means of the five people under each experimental configuration were calculated, as shown in Table 6. There was no significant difference in the results between the two experimental configurations, and the conclusion could be drawn that wearing the exoskeleton could still meet the user's range of motion.

[0151] Table 6 Shoulder range of motion with and without wearing the exoskeleton

[0152]

[0153] (2) Performance verification experiment

[0154] The ANOVA results of screwing at two heights are shown in Table 7. All monitored muscles showed significant effects statistically. Figure 13 The results of paired comparisons of muscle activation are shown. Under the exoskeleton matching conditions for the two tasks, compared with not wearing the exoskeleton, it was found that the muscle activation of all monitored muscles decreased significantly.

[0155] Table 7. F and p values of ANOVA for muscle activation under two tasks

[0156]

[0157] When screwing at a low height, compared with the exoskeleton non-matching condition, the muscle activation of MD, PD, BB, PM, and LD decreased significantly under the exoskeleton matching condition; in addition, under the exoskeleton non-matching condition, the muscle activation of BB was also significantly lower than that under the condition of not wearing the exoskeleton.

[0158] Compared with the exoskeleton non-matching condition, when screwing at a high height, the muscle activation of AD, MD, PD, and PM decreased significantly under the exoskeleton matching condition; the muscle activation of BB and TR under the exoskeleton non-matching condition was significantly lower than that when not wearing the exoskeleton.

[0159] As shown in Table 8, under the condition of exoskeleton matching, the absolute percentage reduction of both tasks is above 15% (AD is up to 22.9% and 23.8% when screwing at low and high heights respectively), and the relative percentage reduction is above 30% (AD is up to 48.3% when tightening at low height, and BB is up to 49.6% when screwing at high height). For the two tasks under the condition of exoskeleton mismatch, the absolute percentage reduction is above 5% (AD is up to 11.9% when screwing at low height, and BB and TR are 11.3% when screwing at high height), and the relative percentage reduction exceeds 9% (AD is up to 24.3% when screwing at high height, and BB is up to 27.7% when screwing at low height). For the same muscle in the same task, the absolute and relative reduction amounts under the exoskeleton matching condition are approximately twice those under the exoskeleton mismatch condition.

[0160] Table 8 Percentage reduction of muscle activation when wearing an exoskeleton

[0161]

[0162] Note: A|B represents the absolute and relative percentage reduction of muscle activation compared with not wearing an exoskeleton.

[0163] The foregoing results verify the effectiveness of the exoskeleton, indicating that the passive shoulder exoskeleton robot provided by the present invention can reduce the shoulder burden, decrease the muscle force of the corresponding muscles, and thus is expected to delay fatigue and reduce the risk of shoulder musculoskeletal diseases.

[0164] It should be noted that the embodiments of the present invention are preferred embodiments and not limitations thereof. It should be pointed out that for those of ordinary skill in the art in the technical field, without departing from the principle of the present invention, modifications can be made to the specific implementation manners or equivalent replacements can be made to some technical features, and they should all be regarded as falling within the scope of the present invention.

Claims

1. A passive shoulder exoskeleton robot for assisting head tasks, characterized in that: The exoskeleton comprises a shoulder module, a passive drive module, a back support module and a flexible module; the shoulder module comprises a horizontal flexion and extension rod (1), a shoulder bending connecting rod (2), a sagittal flexion and extension rod (3) and a front and rear adjustment connecting rod (12); the shoulder module is used to improve the range of shoulder movement when a person wears the exoskeleton; the passive drive module adopts a torque generator (4) for generating a power-assisting torque, and the peak torque and peak torque angle of the power-assisting torque are adjustable; The back support module comprises a back slide rail (5), a waist fixing plate (7), an upper back rod (11) and a lower back rod (9), and the back support module is used to support the overall structure of the exoskeleton; the flexible module comprises a shoulder belt (6), a waist belt (8) and an arm strap (10), and the flexible module is used to connect the exoskeleton to the human body; One end of the shoulder bending link (2) and the front-back adjustment link (12) are connected through a horizontal flexion and extension rod (1) to form a horizontal flexion and extension degree of freedom, with the human body's mid-sagittal plane as the symmetry plane, one on each side; the other end of the shoulder bending link (2) and the torque generator (4) are connected through a sagittal flexion and extension rod (3) to form a sagittal flexion and extension degree of freedom, one on each side; one end of the lower back rod (9) is connected to a waist fixing plate (7) to form a waist rotation degree of freedom, whose rotation axis is perpendicular to the sagittal plane, and the other end of the lower back rod (9) is connected to a back slide rail (5); one end of the upper back rod (11) is connected to the front-back adjustment link (12), and the other end is connected to the back slide rail (5); the arm binding (10) is fixed on the torque generator (4), one on each side; the shoulder strap (6) is respectively connected to the back slide rail (5) and the waist belt (8); the waist belt (8) is respectively connected to the waist fixing plate (7) and the shoulder strap (6); The torque generator (4) is composed of a pulley block (13), a guide rail (14), a steel wire rope (15), a tensile elastic element (16), an eight-shaped ring (17), a pre-tightening bolt (18) and a housing (19); the pulley block (13) includes a No. 1 pulley (131), a No. 2 pulley (132), a No. 3 pulley (133), a No. 4 pulley (134) and a No. 5 pulley (135); The tensile elastic element (16) is used as an energy storage element to provide power; one end of the steel wire rope (15) is fixed on the No. 1 pulley (131), and is wound around the No. 2 pulley (132) and the No. 3 pulley (133) in the middle, and is connected to the tensile elastic element (16) via the No. 4 pulley (134) and the No. 5 pulley (135). The No. 4 pulley (134) and the No. 5 pulley (135) are placed side by side, and their function is to ensure that the direction of the steel wire rope (15) and the tensile elastic element (16) are in a straight line; the No. 2 pulley (132) and the No. 3 pulley are connected to the tensile elastic element (16) in the middle. The wheel (133) is installed on a guide rail slider matched with the guide rail (14) and can slide along the guide rail (14); the other end of the stretching elastic element (16) is connected to the eight-shaped ring (17), and the other end of the eight-shaped ring (17) is connected to the pre-tightening bolt (18), and the pre-tightening bolt (18) adjusts the pre-tightening length of the stretching elastic element (16); the eight-shaped ring (17) contains a rotational freedom in the middle, and its function is to ensure that the stretching elastic element (16) does not rotate when the pre-tightening bolt (18) is rotated; the housing (19) provides protection and support.

2. The passive shoulder exoskeleton robot for assisting over-the-head tasks according to claim 1, characterized in that: The back slide rail (5) comprises a back slide rail body (51), a back slider (52) and a back carbon fiber plate (53); the back slide rail body (51) is fixed on the back carbon fiber plate (53); a groove is provided on the back slide rail body (51), and the back slider (52) is placed in the groove and can slide left and right in the back slide rail body (51); The upper back rod (11) comprises an upper back rod upper portion (111) and an upper back rod lower portion (112); the upper end of the upper back rod upper portion (111) is connected to the end of the front and rear adjustment connecting rod (12) by bolts, wherein the upper end of the upper back rod upper portion (111) has a prefabricated threaded hole, which can change the installation position of the upper back rod upper portion (111) and the front and rear adjustment connecting rod (12); the lower end of the upper back rod upper portion (111) is connected to the upper end of the lower back rod (112) by bolts using a length adjustment hole (20) to adjust the overall length of the exoskeleton upper back rod (11); the lower end of the lower back rod (112) is connected to the back slider (52) by bolts; The lower back rod (9) comprises an upper portion (91) and a lower portion (92). The upper end of the upper portion (91) is fixedly connected to the back carbon fiber plate (53). The lower end of the upper portion (91) is connected to the upper end of the lower portion (92) by bolts via a length adjustment hole (20) to adjust the overall length of the exoskeleton lower back rod (9). The lower end of the lower portion (92) is connected to the waist fixing plate (7) via a rotating joint.

3. The passive shoulder exoskeleton robot for assisting over-the-head tasks according to claim 1, characterized in that: The size of the exoskeleton robot is adjustable, wherein the front and rear adjustment connecting rods (12) are adjustable in length to accommodate people with different back thicknesses, with the back thickness range being 5 to 10 cm; the upper back rod (11) and the lower back rod (9) are adjustable in length to accommodate people with different back lengths, with the back length range being 43.6 to 66.6 cm; the upper back rod can slide left and right along the back slide rail (5) to accommodate people with different shoulder widths, with the shoulder width range being 29.6 to 45.6 cm; the arm straps (10), waist belts (8) and shoulder straps (6) are adjustable in length.

4. The passive shoulder exoskeleton robot for assisting over-the-head tasks according to claim 1, characterized in that: The method for using the exoskeleton robot is as follows: before using the exoskeleton, the user adjusts the position of the No. 1 pulley (131) and the positions of the No. 2 pulley (132) and the No. 3 pulley (133) on the guide rail (14) according to the actual overhead task height and the requirements for the safety limit angle; during the use of the exoskeleton, the user adjusts the size of the exoskeleton through the arm binding (10), the waist belt (8), the shoulder strap (6), the front and rear adjustment connecting rods (12), the upper back rod (11), the lower back rod (9) and the back slide rail (5) to make it conform to the size of the user's body; after putting on the exoskeleton, the user changes the peak torque of the torque generator (4) by adjusting the pre-tightening bolt (18) to meet the user's own needs.

5. A design method for a passive shoulder exoskeleton robot that assists with head tasks, used to design the passive shoulder exoskeleton robot that assists with head tasks as claimed in claim 1, characterized in that: The following steps are involved: Step 1: Design the shoulder module. The design parameters of the shoulder module include the pitch angle φ, the vertical distance d v and horizontal deviation d b ; Among them, the pitch angle φ is the angle between the front and rear adjustment links and the horizontal plane of the human body, and the vertical distance d v Defined as the vertical distance between the user's shoulder rotation center and the front and rear adjustment links, horizontal deviation d b is the horizontal distance between the user's shoulder rotation center and the exoskeleton's shoulder rotation center; the pitch angle φ and the vertical distance d v Used to adjust the space between the acromion and the exoskeleton horizontal flexion and extension bar above it, horizontal deviation d b Used to adjust the deviation distance between the exoskeleton shoulder rotation center and the user's shoulder rotation center; Step 2: Design a passive drive module. The passive drive module uses a torque generator. The torque generator design parameters include K, L i , α, β, r1, r2, r3r, are used to adjust the peak torque and peak torque angle; where K is the stiffness of the tensile elastic element, L i is the initial stretch of the stretch elastic element, α is the angle of pulley No. 1, β is the angle of pulley No. 2, r1 is the distance between the sagittal flexion and extension bar and pulley No. 1, r2 is the distance between the sagittal flexion and extension bar and the guide rail, r3 is the radius of the sagittal flexion and extension bar, and r is the radius of pulley No. 1, pulley No. 2, and pulley No. 3; Step 3: Design a back support module to fit wearers of different body sizes; Step 4: Design flexible modules for fixing the exoskeleton to the human body.

6. The design method of a passive shoulder exoskeleton robot for assisting over-the-head tasks according to claim 5, characterized in that: In step 2, the torque generator design parameters include K, L i , α, β, r1, r2, r3r, used to adjust the peak torque and peak torque angle, specifically: K, L i and r1 mainly affect the peak torque of the power-assist torque curve. As the parameters increase, the peak torque increases. r2 affects the overall length of the torque generator housing. r3 mainly affects the power-assist torque of stage 1. As r3 increases, the power-assist torque of stage 1 increases, but the peak torque of stage 2 remains basically unchanged. r has some influence on the peak torque of the power-assist torque curve and the boundary angle between stage 1 and stage 2. As r increases, the peak torque increases slightly and the boundary angle between stage 1 and stage 2 decreases slightly. α and β mainly affect the peak torque, peak torque angle and boundary angle between stage 1 and stage 2 of the power-assist torque curve. If α increases or β decreases, the peak torque of the power-assist torque curve decreases, the peak torque angle increases, and the boundary angle between stage 1 and stage 2 increases. The definitions of stage 1 and stage 2 are as follows: depending on whether the wire rope is in contact with the sagittal flexion and extension bar, the entire assistance process is divided into two stages: stage 1 is a low-assistance area, in which the wire rope is in contact with the sagittal flexion and extension bar, and the lever arm is very small; stage 2 is a high-assistance area, in which the wire rope is separated from the sagittal flexion and extension bar, and the lever arm first increases and then decreases.

7. The design method of a passive shoulder exoskeleton robot for assisting over-the-head tasks according to claim 5, characterized in that: In step 2, the torque generator generates a boost torque τ exo , the calculation method is: t exo =F s L exo (1) Where F s and L exo They represent the stored elastic potential energy and the lever arm, respectively. The lever arm is the vertical distance from the center of the exoskeleton sagittal flexion and extension rod to the wire rope between pulleys 1 and 2. F s By formula (2) we can obtain F s =KΔL (2) Where K is the stiffness of the tensile elastic element and ΔL is the stretch of the tensile elastic element.

8. The design method of a passive shoulder exoskeleton robot for assisting over-the-head tasks according to claim 7, characterized in that: The calculation formula of the stretching amount ΔL of the stretching elastic element is: ΔL=ΔL(θ s，exo )=L A′B′ (i s，exo )-L A′B′ (max(θ s，exo ))+L i (3) Where L A′B′ is the change in the length of the wire rope between pulley No. 1 and pulley No. 3, θ s，exo is the sagittal flexion and extension angle of the exoskeleton, when θ s，exo When it reaches the maximum value, L A′B′ The shortest length, L i is the initial stretch of the stretch elastic element.

Images