A passive waist assist exoskeleton based on variable stiffness composite elastomers

Abstract

The application discloses a passive waist assisting exoskeleton based on a variable stiffness composite elastomer and relates to the technical field of waist exoskeletons. The two groups of adjusting belts arranged outside the composite elastic backplate are located at the lower ends of the shoulder straps, and the shoulder straps and the adjusting belts are provided with adjusting buckles at the ends close to each other. The passive waist assisting exoskeleton based on the variable stiffness composite elastomer is suitable for the assisting requirements of different bending work scenes, the overall structure adopts a passive design, no external power equipment is needed, the overall weight is lighter, and no additional weight burden is added to the user; the tightness of each part of the exoskeleton can be quickly adjusted through the adjusting buckles and the leg binding adjusting buckles, the exoskeleton is suitable for users with different body shapes, the adaptability is stronger, the load on the waist muscles and the lumbar vertebrae can be effectively shared, the risk of waist strain is reduced, the structure is simple, wearing is convenient, and the exoskeleton is suitable for most bending work scenes.

Description

Technical Field

[0001] This invention relates to the field of lumbar exoskeleton technology, specifically a passive lumbar assistive exoskeleton based on a variable stiffness composite elastomer. Background Technology

[0002] A lumbar assistive exoskeleton is a wearable, lightweight mechanical device whose core function is to provide support and assistance to the lower back when bending over or lifting objects, thereby relieving pressure on the lumbar spine and reducing muscle strain. It is widely used in industrial, logistics, construction, and medical rehabilitation fields. Most existing lumbar assistive exoskeletons are equipped with motors, sensors, and batteries. The sensors capture movements in real time, and the motors provide active assistance, making them intelligent and efficient, but they are also relatively heavy and expensive.

[0003] Patent CN112621722B, authorized by patent publication number CN112621722B, discloses an active waist-assisting exoskeleton for connecting a left leg binding system and a right leg binding system to the human leg. The left waist module or the right waist module is provided with a drive module, and the back module is electrically connected to the left waist module and the right waist module respectively. The drive module is used to provide active torque to the corresponding waist module to form an upward lifting force to realize the lifting assistance of the active waist-assisting exoskeleton or a downward swinging force to realize the following walking assistance of the active waist-assisting exoskeleton.

[0004] Patent CN218138043U discloses an integrated weight-bearing exoskeleton. The lumbar exoskeleton adopts a rigid structure and is rigidly connected to the back mechanism. Therefore, this exoskeleton has higher strength, higher load-bearing capacity, and is more conducive to load distribution. Specifically, the entire lumbar and back mechanisms are rigidly connected, and all three rotational degrees of freedom of the exoskeleton's hip joint mechanism are placed on the side of the human hip joint. The advantage of this structure is that when the human wears the exoskeleton and bears weight, the weight can be effectively transmitted directly to the hip joint mechanism connected to the end of the lumbar mechanism through the lumbar mechanism, thereby transmitting the force to the ground through the lower limb exoskeleton modules on both sides of the human body.

[0005] Patent publication number CN117601105A discloses a flexible lumbar exoskeleton with intelligent driving torque. This flexible exoskeleton includes its overall shape design, EMG signal acquisition of relevant muscle groups during straightening and bending movements, EMG signal processing, hip joint torque estimation algorithm, research on the relationship between hip joint rotation angle and torque, and intelligent driving mechanism design. This flexible exoskeleton conforms to the physiological curves of the human body, does not interfere with the body, and is lightweight while ensuring strength.

[0006] In the aforementioned patents, most lumbar exoskeletons use a rigid backplate combined with an active drive structure. This not only results in a large overall weight, which increases the user's burden during prolonged wear, but also lacks the ability to adjust stiffness, making it unable to adapt to the assistance needs at different bending angles. Furthermore, active exoskeletons rely on electric drive, which leads to short battery life in long-term outdoor work scenarios and high maintenance costs. In addition, some existing passive lumbar exoskeletons use a fixed-stiffness elastic structure to provide assistance, which cannot automatically adjust the assistance stiffness according to the user's bending angle and work needs. When bending at a small angle, the assistance is too great, increasing the feeling of restriction, while when bending at a large angle, the assistance is insufficient and cannot effectively share the load on the lumbar spine, resulting in poor adaptability.

[0007] To address the aforementioned issues, there is an urgent need for innovative designs based on existing exoskeleton structures. Summary of the Invention

[0008] The purpose of this invention is to provide a passive lumbar assistive exoskeleton based on a variable stiffness composite elastomer, in order to solve the problems mentioned in the background art. Existing lumbar exoskeletons are mostly rigid back plates with active drive structures, which are heavy, have a strong burden when worn for a long time, have weak variable stiffness adjustment capabilities, and are difficult to adapt to the assistance needs of different bending angles. Active models rely on electricity, which has limited battery life and high maintenance costs for outdoor operations. Passive models mostly use a fixed stiffness elastic structure, which cannot adaptively adjust stiffness according to bending angle and work requirements. Excessive assistance at small bending angles results in a strong sense of restraint, while insufficient assistance at large bending angles leads to poor lumbar spine reduction and poor overall adaptability.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a passive lumbar support exoskeleton based on a variable stiffness composite elastomer, comprising shoulder straps and a composite elastic backplate disposed between the two sets of shoulder straps; two sets of adjustable webbing disposed on the outer side of the composite elastic backplate are located at the lower end of the shoulder straps, and an adjustment buckle is disposed at the end of the shoulder straps and the adjustable webbing that are close to each other; a pelvic fixation support is disposed at the lower end of the composite elastic backplate; a waist belt is disposed on the outer side of the pelvic fixation support; and a leg-binding adjustment buckle disposed at the lower end of the pelvic fixation support is located at the lower end of the waist belt.

[0010] Preferably, the lower end of the leg-adjusting buckle is provided with a leg-adjusting strap, the lower end of the leg-adjusting strap is provided with a loop, and the lower end of the loop is provided with a knee strap.

[0011] Preferably, the lower end of the knee strap is provided with a knee buckle, and two sets of knee straps, knee buckles and loops are provided at the lower end of the pelvic fixation support.

[0012] Preferably, the assist structure provided on the outer side of the composite elastic backplate can provide assistance for the waist to stand upright. The assist structure includes a mounting frame, which is located at the rear end of the pelvic fixation support. The mounting frame has a fixing shaft inside, which allows the mounting frame to stably install the coiled spring through the fixing shaft, ensuring that the coiled spring can stably extend and retract the connecting flat rope, thus providing a structural basis for subsequent variable stiffness assistance.

[0013] Preferably, the coiled spring on the outside of the fixed shaft is located inside the mounting frame, and the end of the coiled spring away from the fixed shaft is connected to a connecting flat rope. Furthermore, the two sets of anti-wear shafts inside the mounting frame are located on both sides of the connecting flat rope. This allows the coiled spring to stably wind up the connecting flat rope, while the anti-wear shafts can limit and protect the connecting flat rope, preventing wear caused by friction between the connecting flat rope and the inner wall of the mounting frame during winding and unwinding, thus extending the service life of the structure.

[0014] Preferably, the assist structure further includes a connecting block, which is located at the rear end of the shoulder strap, and the elastic traction belts at the lower ends of the two sets of connecting blocks are connected to each other, while an elastic tension belt is connected to the outer side of the connection position of the two sets of elastic traction belts.

[0015] Preferably, the rear end of the composite elastic back plate is provided with a limiting block, and two sets of limiting shafts are rotatably installed inside the limiting block. The two sets of limiting shafts are located on both sides of the elastic tension band, and the two sets of limiting shafts are respectively located at the lower ends of the two sets of elastic traction bands. This allows the limiting shafts to guide and limit the elastic tension band and the elastic traction band, preventing the elastic tension band from shifting or misaligning during the pulling process and ensuring the stable transmission of the assisting force.

[0016] Preferably, the two sets of adjustment frames at the rear end of the composite elastic backplate are located at the lower end of the limiting block, and pulleys A and B are rotatably installed inside the adjustment frames. At the same time, the lower adjustment frame is fixedly connected to the composite elastic backplate, which allows the connecting flat rope to pass around pulleys A and B in sequence. By utilizing the radius difference between pulleys A and B, the stroke of the connecting flat rope is gradually increased as the bending angle increases, making the variable stiffness adjustment smoother and more stable, and adapting to the assistance needs of different bending angles.

[0017] Preferably, a connecting flat rope is wound around the outer side of pulleys A and B, and the end of the connecting flat rope away from the coiled spring is fixedly connected to the traction shaft inside the upper adjustment frame. The radius of pulley A is larger than that of pulley B. At the same time, the two sets of pulleys A are located on both sides of the two sets of pulleys B, so that the upper adjustment frame can pull the connecting flat rope with the user's bending motion. The greater the bending angle, the greater the length of the connecting flat rope pulled out, and the greater the rebound force generated by the coiled spring being stretched. At the same time, in conjunction with the variable stiffness elastic traction belt and elastic tension belt structure, the assist stiffness will increase synchronously with the bending angle. This achieves gentle assistance and reduced restraint when bending at a small angle, and increased stiffness and sufficient support when bending at a large angle. The adaptive adjustment can automatically adapt to the assistance needs of different bending work scenarios without additional manual adjustment or electric drive. At the same time, the overall structure adopts a passive design, which does not require external power equipment, and the overall weight is lighter, without adding extra weight burden to the user.

[0018] Preferably, the shoulder strap and the composite elastic back panel are arranged symmetrically about the composite elastic back panel, and the length of the composite elastic back panel is greater than the distance between the two sets of adjustment frames. The adjustment frames are located on the central axis of the composite elastic back panel, and the upper adjustment frame is in close contact with the composite elastic back panel.

[0019] Compared with existing technologies, the beneficial effects of this invention are as follows: This passive lumbar assistive exoskeleton based on a variable stiffness composite elastomer can adjust the output of assistance according to the user's lumbar bending angle, providing greater assistance when the bending angle increases, thus adapting to the assistance needs of different bending work scenarios. Simultaneously, the overall structure adopts a passive design, requiring no external power equipment, resulting in a lighter overall weight and no additional burden on the user. The tightness of various parts of the exoskeleton can be quickly adjusted via adjustment buckles and leg strap adjustment buckles, adapting to users of different body types, thus enhancing its adaptability. During long-term bending work, it can effectively distribute the load on the lumbar muscles and lumbar spine, reducing the risk of lumbar strain. The structure is simple, easy to wear, and suitable for most bending work scenarios.

[0020] 1. This passive lumbar support exoskeleton based on variable stiffness composite elastomer can automatically adjust its stiffness according to the angle of the user's bending motion by setting a composite elastic back plate with variable stiffness characteristics. When the bending range increases, the structural stiffness is increased simultaneously to provide greater support force. When in an upright state, it maintains low stiffness and will not cause additional restriction to the user's normal activities. 2. The device adopts a passive structure design, which does not require an external power source and control module. This reduces the overall weight and manufacturing cost of the device, and avoids the limitation of battery life on the usage scenarios. It is suitable for long-term outdoor work and bending over to carry things. 3. The shoulder strap length and leg strap length can be flexibly adjusted through the adjustment buckle and leg strap adjustment buckle to adapt to the wearing needs of users with different body types. At the same time, the multiple sets of limiting and transmission structures can stably store the deformation energy generated by bending over and release it during the standing process, assisting users to complete the upright movement, effectively reducing the load on the waist muscles and lumbar spine, and reducing the waist injury caused by long-term bending work.

[0021] 4. Furthermore, the variable stiffness composite elastomer is prepared by layering elastic materials with different moduli. The surface layer is a low-modulus flexible elastic matrix, and multiple layers of high-modulus elastic support sheets are embedded inside. There are reserved gaps between the support sheets. As the bending angle increases, the support sheets gradually come together to form an overall support structure, so that the overall stiffness automatically increases with the deformation amplitude. Stiffness self-adaptive adjustment can be achieved without additional control structure.

[0022] 5. Furthermore, the coiled spring inside the mounting frame can work in sync with the variable stiffness backplate to store and release energy. When the user bends over, the connecting flat rope is pulled by the upper adjustment frame, causing the coiled spring to tighten and store elastic potential energy. At this time, as the bending angle increases, the stiffness of the composite elastic backplate increases simultaneously. Combined with the potential energy stored in the coiled spring, it can provide support for the waist, counteract the torque generated by the bending action, and reduce the stress on the waist. When the user stands up from the bent-over position, the coiled spring releases the stored elastic potential energy and pulls the connecting flat rope back. Combined with the rebound force of the composite elastic backplate, it helps the user to smoothly complete the standing action, further reducing the force that the waist needs to output during the standing process.

[0023] 6. Furthermore, there is no need to learn how to adjust it, carry spare parts, or worry about improper adjustment. Workers can simply put on the exoskeleton and start working, making it suitable for large-scale enterprise deployment. It offers perfect height adaptability; one size fits all heights (155-190cm), eliminating the need to produce multiple sizes and reducing inventory costs. The non-linear assist curve of the backplate and the lever adaptive mechanism provide maximum assistance when bending over deeply and when most prone to injury, effectively reducing pressure on the lumbar intervertebral discs. The passive design requires no batteries or motors, resulting in no operating costs. The composite material has a long lifespan and low maintenance costs. The number of parts is small, resulting in low manufacturing costs. Attached Figure Description

[0024] Figure 1 This is a top-view three-dimensional structural diagram of the present invention; Figure 2 This is a rear-view stereoscopic structural diagram of the present invention; Figure 3 This is a top-view three-dimensional structural diagram of the connecting block of the present invention; Figure 4 This is a top-view three-dimensional structural diagram of the elastic traction belt of the present invention; Figure 5 This is a top-view three-dimensional structural diagram of the adjustment frame of the present invention; Figure 6 This is a top-view three-dimensional structural diagram of pulley A of the present invention; Figure 7 This is a top-view three-dimensional structural diagram of pulley B of the present invention; Figure 8 This is a front view structural diagram of the flat rope connection state of the present invention.

[0025] In the diagram: 1. Shoulder strap; 2. Composite elastic back panel; 3. Adjustment buckle; 4. Adjustment webbing; 5. Pelvic fixation support; 6. Waist belt; 7. Leg strap adjustment buckle; 8. Leg adjustment strap; 9. Ring buckle; 10. Knee strap; 11. Knee buckle; 12. Mounting frame; 13. Fixing shaft; 14. Coil spring; 15. Connecting block; 16. Elastic traction belt; 17. Limiting block; 18. Limiting shaft; 19. Elastic tension belt; 20. Adjustment frame; 21. Pulley A; 22. Pulley B; 23. Connecting flat rope; 24. Anti-wear shaft; 25. Traction shaft. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Example 1: In a specific embodiment, the present invention provides the following technical solution: a passive lumbar support exoskeleton based on a variable stiffness composite elastomer, such as... Figures 1-4 The process of wearing and using the waist-assisting exoskeleton is shown in the figure.

[0028] The back panel consists of shoulder straps 1 and a composite elastic backplate 2 positioned between the two sets of shoulder straps 1. Two sets of adjustable webbing 4 are located on the outer side of the composite elastic backplate 2 at the lower end of the shoulder straps 1, with adjustable buckles 3 at the ends of the shoulder straps 1 and the adjustable webbing 4 that are close to each other. A pelvic fixation support 5 is located at the lower end of the composite elastic backplate 2. A waist belt 6 is located on the outer side of the pelvic fixation support 5. A leg-binding adjustment buckle 7 is located at the lower end of the waist belt 6. A leg-binding adjustment strap 8 is located at the lower end of the leg-binding adjustment buckle 7, with a loop 9 at the lower end of the leg-binding adjustment strap 8. A knee strap 10 is located at the lower end of the loop 9, with a knee buckle 11 at the lower end of the knee strap 10. Two sets of knee straps 10, knee buckles 11, and loops 9 are located at the lower end of the pelvic fixation support 5. The assistive structure provides support for upright posture. The assistive structure includes a mounting frame 12, which is positioned at the rear end of the pelvic fixation support 5. A fixing shaft 13 is located inside the mounting frame 12. A coiled spring 14, located outside the fixing shaft 13, is positioned inside the mounting frame 12. A connecting flat rope 23 is connected to the end of the coiled spring 14 away from the fixing shaft 13. Two sets of anti-wear shafts 24 are located on either side of the connecting flat rope 23 inside the mounting frame 12. The shoulder strap 1 and the composite elastic backplate 2 are symmetrically arranged about the composite elastic backplate 2. The length of the composite elastic backplate 2 is greater than the distance between the two sets of adjustment frames 20. The adjustment frames 20 are located on the central axis of the composite elastic backplate (2), and the upper adjustment frame (20) is tightly fitted to the composite elastic backplate (2). When using this passive lumbar assistive exoskeleton based on variable stiffness composite elastomer, the exoskeleton needs to be worn on the user's body first. The distance between the shoulder straps 1 and the adjustable webbing 4 can be adjusted by adjusting buckle 3, making it convenient for users with different shoulder widths to wear. During the wearing process, the waist circumference of the waist belt 6 can be automatically adjusted so that the composite elastic back plate 2 can fit snugly against the user's back. Then, the knee buckle 11 can be adjusted to fix the knee strap 10 to the lower end of the knee. At the same time, when wearing the lumbar assistive exoskeleton, the user's upper body is in a forward-leaning position, which allows the composite elastic back plate 2 to be in a bending and energy storage state. When standing up, the rebound of the composite elastic back plate 2 directly provides assistance to pull the shoulder straps 1 upward, thus completing the initial assistance process of the lumbar assistive exoskeleton. By providing assistance through the composite elastic back plate 2, the assistance effect can be guaranteed while reducing the cost and structural complexity of the lumbar assistive exoskeleton.

[0029] Example 2: In one specific embodiment, such as Figures 1-8 As shown, the secondary lumbar assistance process of this lumbar assist exoskeleton is disclosed.

[0030] The assist structure also includes connecting blocks 15, which are located at the rear end of the shoulder strap 1. Elastic traction straps 16 at the lower ends of the two sets of connecting blocks 15 are interconnected. Elastic tension straps 19 are connected to the outer sides of the connection points of the two sets of elastic traction straps 16. A limiting block 17 is located at the rear end of the composite elastic backplate 2, and two limiting shafts 18 are rotatably mounted inside the limiting block 17. The two limiting shafts 18 are located on both sides of the elastic tension straps 19, and are respectively located at the lower ends of the two sets of elastic traction straps 16. The rear end of the composite elastic backplate 2... The two sets of adjustment frames 20 are located at the lower end of the limiting block 17, and pulleys A21 and B22 are rotatably installed inside the adjustment frame 20. At the same time, the lower adjustment frame 20 is fixedly connected to the composite elastic back plate 2. The outer sides of pulleys A21 and B22 are wrapped with connecting flat ropes 23, and the end of the connecting flat ropes 23 away from the coiled spring 14 is fixedly connected to the traction shaft 25 inside the upper adjustment frame 20. The radius of pulley A21 is larger than the radius of pulley B22, and the two sets of pulleys A21 are located on both sides of the two sets of pulleys B22.

[0031] When using this passive lumbar support exoskeleton based on a variable stiffness composite elastomer, the compression of the coiled spring 14 directly assists in straightening the waist. When the waist is bent, the shoulder strap 1, through the connecting block 15, keeps the elastic traction belt 16 and elastic tension belt 19 in a stretched state. At the same time, the elastic tension belt 19 directly pulls the upper adjustment frame 20 upward, and the connecting flat rope 23 expands on the outside of the coiled spring 14, while the coiled spring 14 coils up. When the waist is biased towards an upright position, the coiled spring 14 expands. Zhang pulls the upper mounting frame 12 downwards via the connecting flat rope 23. At this time, the downward movement of the mounting frame 12 will pull the connecting block 15 on the outside of the shoulder strap 1 through the elastic traction belt 16 and the elastic tension belt 19, assisting the user's waist to be in a slightly upright position. Meanwhile, the pulleys A21 and B22 inside the upper adjustment frame 20 form a movable pulley group, which can amplify the force of the coil spring 14, so that the tension on the connecting block 15 on the outside of the shoulder strap 1 is 4 to 5 times the coiling force of the coil spring 14, thereby further enhancing the waist assist exoskeleton's assisting effect on the waist.

[0032] Example 3: Based on the above examples, such as... Figures 1-8 The overall usage process of this lumbar support exoskeleton is shown in the figure.

[0033] When using this passive lumbar assist exoskeleton based on variable stiffness composite elastomer, users can flexibly adjust the tightness of the legs and shoulders / back by adjusting the leg strap adjustment buckles 7 and 3 according to their own needs and actual usage scenarios. This adapts to users of different body shapes while ensuring the overall stability of the exoskeleton and preventing displacement or slippage during wear. The two sets of limiting shafts 18 can limit the elastic tension band 19, preventing it from shifting or misaligning during traction movement and ensuring stability during traction assistance. The anti-wear shaft 24 can... The sides of the connecting flat rope 23 are protected to prevent excessive friction between the connecting flat rope 23 and the inner wall of the mounting frame 12 during the winding and unwinding process, thus extending the service life of the connecting flat rope 23. During the process of the user bending over and standing up, the user can simultaneously receive the rebound assistance of the composite elastic back plate 2 and the traction assistance of the coiled spring 14. The superposition of dual assistance can effectively reduce the load on the waist muscles and lumbar spine, and relieve waist fatigue caused by long-term bending work. At the same time, the overall structure does not require an external power source, is lighter, and will not cause additional burden on the user, increasing the overall creativity.

[0034] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

[0035] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A passive waist-assisting exoskeleton based on a variable stiffness composite elastomer, comprising shoulder straps (1) and a composite elastic backplate (2) disposed between two sets of shoulder straps (1). Its features are: Two sets of adjustable webbing (4) are provided on the outer side of the composite elastic back plate (2) at the lower end of the shoulder strap (1), and an adjustment buckle (3) is provided at the end of the shoulder strap (1) and the adjustable webbing (4) that are close to each other. A pelvic fixation support (5) is provided at the lower end of the composite elastic back plate (2), and a waist belt (6) is provided on the outer side of the pelvic fixation support (5). A leg adjustment buckle (7) provided at the lower end of the pelvic fixation support (5) is located at the lower end of the waist belt (6).

2. The passive lumbar support exoskeleton based on a variable stiffness composite elastomer according to claim 1, characterized in that: The lower end of the leg-adjusting buckle (7) is provided with a leg-adjusting strap (8), and the lower end of the leg-adjusting strap (8) is provided with a ring buckle (9), and the lower end of the ring buckle (9) is provided with a knee strap (10).

3. The passive lumbar support exoskeleton based on a variable stiffness composite elastomer according to claim 2, characterized in that: The lower end of the knee strap (10) is provided with a knee buckle (11), and the knee strap (10), knee buckle (11) and ring buckle (9) are provided in two sets at the lower end of the pelvic fixation support (5).

4. The passive lumbar support exoskeleton based on a variable stiffness composite elastomer according to claim 3, characterized in that: The auxiliary structure provided on the outside of the composite elastic back plate (2) can provide assistance for the waist to stand upright. The auxiliary structure includes a mounting frame (12), which is located at the rear end of the pelvic fixation support (5), and a fixing shaft (13) is provided inside the mounting frame (12).

5. The passive lumbar support exoskeleton based on a variable stiffness composite elastomer according to claim 4, characterized in that: The coiled spring (14) provided on the outside of the fixed shaft (13) is located inside the mounting frame (12), and the end of the coiled spring (14) away from the fixed shaft (13) is connected to the connecting flat rope (23), and the two sets of anti-wear shafts (24) provided inside the mounting frame (12) are located on both sides of the connecting flat rope (23).

6. The passive lumbar support exoskeleton based on a variable stiffness composite elastomer according to claim 5, characterized in that: The assist structure also includes a connecting block (15), and the connecting block (15) is located at the rear end of the shoulder strap (1). The elastic traction belts (16) located at the lower ends of the two sets of connecting blocks (15) are connected to each other, and an elastic tension belt (19) is connected to the outside of the connection position of the two sets of elastic traction belts (16).

7. A passive lumbar support exoskeleton based on a variable stiffness composite elastomer according to claim 6, characterized in that: The rear end of the composite elastic back plate (2) is provided with a limiting block (17), and two sets of limiting shafts (18) are rotatably installed inside the limiting block (17). The two sets of limiting shafts (18) are located on both sides of the elastic tension belt (19), and the two sets of limiting shafts (18) are located at the lower ends of the two sets of elastic traction belts (16).

8. The passive lumbar support exoskeleton based on a variable stiffness composite elastomer according to claim 7, characterized in that: The two sets of adjustment frames (20) at the rear end of the composite elastic back plate (2) are located at the lower end of the limiting block (17), and the adjustment frames (20) are rotatably installed with pulleys A (21) and B (22), while the lower adjustment frame (20) is fixedly connected to the composite elastic back plate (2).

9. A passive lumbar support exoskeleton based on a variable stiffness composite elastomer according to claim 8, characterized in that: The outer sides of pulleys A (21) and B (22) are wrapped with connecting flat ropes (23), and the end of the connecting flat ropes (23) away from the coil spring (14) is fixedly connected to the traction shaft (25) inside the upper adjustment frame (20). The radius of pulley A (21) is larger than that of pulley B (22), and the two sets of pulleys A (21) are located on both sides of the two sets of pulleys B (22).

10. A passive lumbar support exoskeleton based on a variable stiffness composite elastomer according to claim 9, characterized in that: The shoulder strap (1) and the composite elastic back plate (2) are symmetrically arranged about the composite elastic back plate (2), and the length of the composite elastic back plate (2) is greater than the distance between the two sets of adjustment frames (20). The adjustment frames (20) are located on the central axis of the composite elastic back plate (2), and the upper adjustment frame (20) is closely fitted with the composite elastic back plate (2).

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