Unpowered lightweight knee joint assisted rehabilitation training exoskeleton

Abstract

This invention discloses a lightweight, non-powered knee-joint assistive rehabilitation exoskeleton, comprising a thigh-side interactive structure, a knee joint pivot structure, and a lower leg support structure connected from top to bottom. The thigh-side interactive structure interacts with the thigh side of the body, allowing for a fitted fit to the thigh muscles. A steel wire is incorporated into the thigh-side interactive structure; adjusting the tension of the wire adjusts the opening degree of the thigh-side structure, accommodating individuals with varying leg sizes. The knee joint pivot structure simulates the knee joint's flexion and extension freedom, rotating via two pairs of meshing gears and adjusting the passive assist force via a pair of force-transmitting cams. The lower leg support structure supports the lower leg during knee flexion and extension. This invention caters to individuals with different leg sizes, allows for adjustable assist force, and meets the assistive device needs of patients at various stages of rehabilitation.

Description

Technical Field

[0001] This invention relates to the field of knee joint assistive training exoskeleton technology, specifically to a non-powered, lightweight knee joint assistive rehabilitation training exoskeleton. Background Technology

[0002] Traditional knee rehabilitation training methods require guidance from a professional therapist in a specific location, which is limited by time and the number of participants, resulting in low efficiency. Furthermore, patients may not be able to train correctly after leaving the guidance area. The equipment is bulky, complex in structure, and inconvenient to carry, limiting patients from training at home or other locations.

[0003] Electric or pneumatic equipment requires an external power source, resulting in high costs, energy consumption, and noise. It cannot be used without the corresponding energy source, and maintenance is cumbersome. In addition, the standardized specifications of traditional equipment make it difficult to meet the individual needs of different patients, which may affect training effectiveness or cause secondary injuries.

[0004] Exoskeletons have certain advantages for knee joint rehabilitation, but they also have problems: most existing exoskeletons use metal materials and have complex structures, making them heavy, increasing the burden on patients, affecting the naturalness and comfort of movement, and hindering rehabilitation.

[0005] Existing exoskeletons have fixed structural specifications, making it difficult to meet the diverse needs of patients with different body types. There is a need for an exoskeleton robot that is highly adaptable to different body types.

[0006] In addition, the power system is complex, has many components, is costly, heavy, has a high probability of failure, is difficult to maintain and repair, and limits its use time and flexibility.

[0007] The market lacks exoskeleton devices that combine lightweight and non-powered features. Lightweight design can reduce burden, improve comfort and effectiveness, while non-powered solutions can avoid power system problems, reduce costs and maintenance difficulty, and make the equipment simpler and more reliable.

[0008] Some existing passive exoskeleton structures directly use rigid springs or spring-linkage structures to assist the knee joint, failing to achieve adaptive adjustment of knee joint torque. Some passive exoskeleton structures, such as the passive knee exoskeletons in patents CN202110210958.3 and CN202121419223.3, only allow the joint's auxiliary torque to change linearly with the angle during knee flexion. However, the torque borne by the human knee joint during knee flexion is not linear with the angle, requiring a specific structure to adjust the magnitude of the auxiliary torque. Summary of the Invention

[0009] To overcome the shortcomings of the existing technology, this invention provides a lightweight, unpowered knee joint assistive rehabilitation training exoskeleton. Through an adjustable passive force transmission structure connected to a cam by a gas spring, it can accommodate people with different leg sizes. The amount of assistive force can be adjusted to meet the assistive needs of patients at various rehabilitation stages. It is lightweight, simple in structure, flexible in movement, highly comfortable, and easy to wear, accelerating the rehabilitation process for knee joint patients while reducing their pain.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0011] A lightweight, non-powered knee joint assistive rehabilitation training exoskeleton includes a thigh side interactive structure 1, a knee joint pivot structure 2, and a lower leg support structure 3 connected from top to bottom;

[0012] The thigh side interactive structure 1, the knee joint pivot structure 2, and the calf support structure 3 are symmetrically installed on both sides of the human body, corresponding to the left and right legs respectively.

[0013] The thigh-side interactive structure 1 is used to achieve interaction with the thigh side of the human body, so as to fit the thigh muscle side of the human body. The thigh-side interactive structure 1 is provided with steel wire. By adjusting the tension of the steel wire rope, the opening degree of the thigh-side interactive structure 1 can be adjusted to meet the needs of people with different leg thicknesses.

[0014] The knee joint pivot structure 2 is used to simulate the flexion and extension degrees of freedom of the knee joint. It rotates through two pairs of meshing gears and adjusts the passive auxiliary force through a pair of force transmission cams.

[0015] The lower leg support structure 3 is used to support the lower leg during knee flexion and extension of the knee joint pivot structure 2.

[0016] Furthermore, the thigh-side interactive structure 1 includes a separate U-shaped leg wrap shell 4, a thigh-side elastic outer cover 5, a thigh support shell 6, and a gas spring buffer structure;

[0017] The inner side of the split U-shaped leg wrap shell is closely attached to the outer side of the left and right thighs. The outer side of the split U-shaped leg wrap shell 4 is provided with a protruding structure. The protruding structure is inserted into the thigh support shell 6. The thigh support shell 6 is a hollow structure with a cuboid shape.

[0018] The lower end of the separate thigh wrap shell 4 is also connected to a gas spring device via a threaded nut.

[0019] The separate U-shaped leg wrap shell 4 is provided with a cable hole, through which a steel wire rope is passed and connected to the thigh side elastic cover 5. The thigh elastic cover 5 and the two separate U-shaped leg wrap shells 4 are connected by the steel wire rope. A steel wire rope tension adjustment knob is provided on the U-shaped leg wrap shell.

[0020] The detachable U-shaped leg wrap shell 4 has two holes 42 on its protruding structure, which are matched and connected by threaded nuts and two pairs of holes 48 on the left and right thigh support shells 6.

[0021] The outer surface of the arc-shaped plate of the split U-shaped leg wrap 4 is provided with four small circular holes arranged in a square on both sides for fixing the nylon straps and flexible padding.

[0022] The U-shaped outer shell 4 of the split U-shaped leg wrap has four transverse inner holes on the surface of the U-shaped outer shell near the front of the thigh, namely transverse inner hole 1 44, U-shaped inner hole 1 45, U-shaped inner hole 2 46 and transverse inner hole 2 47.

[0023] The two horizontal inner holes 44 and 47 are horizontally penetrating, while the two U-shaped inner holes 45 and 46 are U-shaped and are used for winding the wire rope. The upper and lower holes are used to connect the tensioning cover 5 with the wire rope. The outer side of the detachable U-shaped leg cover 4 is provided with a circular groove for placing the wire rope tensioning knob.

[0024] The thigh-side elastic outer cover 5 has a symmetrical structure. Four holes are set on the left and right sides in a direction parallel to the surface of the structure. U-shaped protrusions are set on the outside of the four holes. The openings of the U-shaped protrusions are arranged outwards and in pairs in a U-shape for the wire rope to run.

[0025] The thigh elastic outer cover 5 is connected to the separate U-shaped leg wrap shell 4 by a steel wire rope through four symmetrical holes on both sides. When worn, it is located in the middle of the two separate U-shaped leg wrap shells 4 and covers the upper thigh.

[0026] Furthermore, the specific routing method of the steel wire rope is as follows: the steel wire rope starts from the middle adjustment knob installed in the circular groove 43 on the separate U-shaped leg wrap shell 4. The starting point of the steel wire rope is fixed on the purchased middle adjustment knob. Then the steel wire rope is wrapped around the outside of the middle adjustment knob, and then comes out from the circular groove 43, passes through the small horizontal inner hole 44 at the upper end of the separate U-shaped leg wrap shell 4, reaches one end of the U-shaped hole on the upper side of the thigh side elastic outer cover 5, passes through the U-shaped hole, returns to the middle U-shaped inner hole 45 of the separate U-shaped leg wrap shell 4, passes through and exits from the second U-shaped inner hole 46, then returns to the other U-shaped hole of the thigh side elastic outer cover 5 and passes through, finally returns to the small horizontal inner hole 47 at the lower end of the separate U-shaped leg wrap shell 4 and passes through, and returns to the elastic adjustment knob in the middle of the separate U-shaped leg wrap shell 4, thus completing the routing of the steel wire rope on the thigh side.

[0027] The thigh support shell 6 has two holes 48 on its upper and lower inner sides respectively. The two holes 48 on the upper side are used to correspond to the holes 42 on the protruding structure of the inserted split U-shaped leg wrap shell 4, and are used to fix the split U-shaped leg wrap shell 4. The two holes 49 at the lower end are matched with gear 16 and gear 2 17 respectively, and are used to connect gear 16 and gear 2 17. Gear 16 and gear 2 17 are respectively set on both sides of the lower end of the split U-shaped leg wrap shell 4.

[0028] The inner side of the thigh support shell 6 is fixed to the thigh side fitting arc plate 7, which fits the thigh. The thigh side fitting arc plate 7 has 3 small holes on each of the left and right sides for fixing the nylon straps, and a flexible pad is pasted on the nylon straps. The entire shell is made of carbon fiber material, which ensures the lightweight structure.

[0029] The gas spring buffer structure includes a hydraulic head 8, with a hydraulic push rod 9 and a hydraulic push rod 10 fixedly connected to the lower ends of the hydraulic head 8 respectively; the hydraulic push rod 9 is connected to a hydraulic terminal 13 via a hydraulic cylinder 11; the hydraulic push rod 10 is connected to a hydraulic terminal 14 via a hydraulic cylinder 12.

[0030] The top of the hydraulic head 8 has a threaded hole. The threaded hole is connected to the threaded hole below the split U-shaped leg shell 4 through a tension threaded support. At the same time, the power supply wire is tied to the middle hole of the hydraulic head 8 as the power supply end. The wire passes around the power transmission circular cam 20 and the curved cam 34 and reaches the tension adjustment knob 37 on the lower leg side to transmit the buffer resistance of the gas spring.

[0031] The gas spring buffer structure is installed inside the thigh support shell 6. Through the perforated hydraulic terminal 13 and hydraulic terminal 2 14, the gear 16 and gear 2 17 are clamped on the outside and correspond to the two small holes on the upper side of the two gears. Then it is connected to the two holes 49 on the lower side of the thigh support shell 6.

[0032] Furthermore, the hydraulic push rod 9 and the hydraulic cylinder 11 are locked at both ends, the hydraulic cylinder 11 is completely sealed, and when the hydraulic push rod 9 slides in the middle groove, it will compress air, thereby generating buffer resistance. The lower end of the hydraulic cylinder 11 is connected to the hydraulic terminal 13 through an internal thread. The hydraulic terminal 13 has a hole that connects to a hole 49 at the lower end of the thigh support shell 6.

[0033] The hydraulic push rod 210 and the hydraulic cylinder 212 are locked at both ends. The hydraulic cylinder 212 is completely sealed. When the hydraulic push rod 210 slides in the middle groove, it will compress air, thereby generating buffer resistance. The lower end of the hydraulic cylinder 212 is connected to the hydraulic terminal 214 through an internal thread. The hydraulic terminal 214 has a hole that connects to another hole 49 at the lower end of the thigh support shell 6.

[0034] Furthermore, the knee joint pivot structure 2 includes two pairs of partially meshing gears, namely gear one 16, gear three 32 and gear two 17, gear four 33.

[0035] Gear 1 (16) and Gear 3 (32) mesh; Gear 2 (17) and Gear 4 (33) mesh.

[0036] Gear 16 and gear 27 are attached to one side of the circular cam 20 via flat washer 121 and to the other side via flat washer 22.

[0037] Gear 32 and gear 43 are attached to one side of the curved cam 34 by flat washer 431 and to the other side by flat washer 30.

[0038] Cover plate 1 25 and cover plate 2 26 are respectively provided on both sides of the two pairs of incompletely meshing gears. Cover plate 1 25 and cover plate 2 26 are covered with packaging shell 15 on the outside.

[0039] The gear 16, gear 27, flat washer 21, circular cam 20, flat washer 22, cover plate 1 25, cover plate 2 26 and packaging shell 15 are provided with through holes at the same corresponding positions. Hex bolt 23 passes through the above through holes and is fixed by hex nut 24 to connect the above components together.

[0040] Gear 32, gear 43, flat washer 431, curved cam 34, flat washer 30, cover plate 125, cover plate 26 and packaging shell 15 are provided with through holes at the same corresponding positions. Hex bolt 29 passes through the above through holes and is fixed by hex nut 28 to connect the above components together.

[0041] Gear 16 and gear 27 are arranged side by side, gear 32 and gear 43 are arranged side by side, and the other end of each gear that is not meshed is a square plate structure with through holes. The through holes on gear 16 and gear 217 match the through holes on the lower side of the thigh support shell 6 for connection.

[0042] The through holes on gear 32 and gear 43 match the through holes on the lower leg support structure 3 for connection.

[0043] The first gear 16 and the second gear 17 have the same module and pitch circle radius, which ensures smooth transmission. The number of teeth is designed to be 6 each.

[0044] The gears 32 and 43 have the same module and pitch circle radius, ensuring smooth transmission. The number of teeth is designed to be 5 each.

[0045] It provides a rotation range of approximately 120° within the smooth meshing range of the gears, and the remaining rotation gradually moves to the meshing limit position, where the resistance gradually increases, thereby achieving control of the rotation angle range and angle limit.

[0046] The circular cam 20 and the curved cam 34 constitute a cam-based force transmission structure. The circular cam 20 is a circle with a fixed radius, while the calf-side cam 34 is designed according to requirements to adapt to force transmission needs in different scenarios. Since the calf-side cam 34 is fixed in the calf support structure 3, it will form an angle with the circular cam 20 during the movement of the mechanism. This angle has a linear relationship with the knee joint angle. By designing the tangent radius of the cam 34 and cam 20 at different angles, the magnitude of the final output auxiliary torque can be controlled.

[0047] Four flat pads are used to support the two pairs of meshing gears. The cam has a groove in the middle for winding the wire rope. One end of the wire rope is connected to the hydraulic head 8, passes around the force transmission cam, and the other end is connected to the tension adjustment knob of the lower leg. During operation, the torque can be effectively transmitted through the cam.

[0048] Furthermore, the lower leg support structure 3 includes a lower leg support plate 35, a winding rope tension adjustment wheel 37, a spring pin 38, and a lower leg adaptability adjustment plate;

[0049] The lower leg support plate 35 is used to provide support for the lower leg side when assisting.

[0050] The winding rope tension adjustment wheel 37 and spring pin 38 are used to adjust the tension of the winding rope, thereby adjusting the preload of the assist device. The winding rope tension adjustment wheel 37 winds the winding rope, and the winding length is adjusted by rotation. The spring pin 38 is used to lock the winding rope tension adjustment wheel 37 to maintain a certain winding length.

[0051] The calf adaptation adjustment plate 40 is used to adjust the opening degree of the lower side of the calf. It is connected to the lower side of the calf support plate 35 through the hinge 39. The opening degree can be adjusted through the one degree of freedom provided by the hinge, thereby adapting to the characteristic of the calf tapering downwards.

[0052] The uppermost part of the calf support plate 35 has two small holes for connecting the through holes on the square plate structure of gear 32 and gear 43. The parallel gears are connected by threaded nuts. Gear 32 and gear 43 have an inward fold at the bottom to adapt to the characteristic of the thigh tapering towards the calf. Higher strength aluminum alloy material is used to ensure strength.

[0053] A calf-side fitting arc plate 36 is installed on the inner side of the calf support plate 35. The calf-side fitting arc plate 36 fits against the calf. The calf-side fitting arc plate 36 is installed and fixed through small holes on the calf support plate 35.

[0054] The lower leg support plate 35 is provided with a slender rectangular groove that transitions to a circle. The circular groove is used to install the pretension adjustment wheel 37. The adjustment wheel 37 has a hole in the center. After being installed on the outside of the lower leg support plate 35 through the circular groove, the inner lower leg side fitting arc plate 36 is also provided with a hole at the position opposite to the center hole of the pretension adjustment wheel 37. Thus, the lower leg side fitting arc plate 36 and the pretension adjustment wheel 37 are connected to both sides of the lower leg support plate 35 by threaded nuts.

[0055] A small boss is provided below the circular groove, and a small internal thread hole is provided in the center of the boss for placing the spring pin 38. A hinge 39 is installed on the small leg support plate 35 below the spring pin 38.

[0056] The winding rope tension adjustment device includes a pre-tension adjustment wheel 37 and a spring pin 38. The pre-tension adjustment wheel 37 is installed by setting threads on the outside of the lower leg support plate 35. The pre-tension adjustment wheel 37 is used to adjust the tension of the winding rope. The pre-tension adjustment wheel 37 is designed with a toothed structure, and a groove is designed at the lower end for installing the spring pin 38. In the working state, the spring pin 38 locks the pre-tension adjustment wheel 37. When tension adjustment is required, simply pull out the spring pin 38 and rotate the pre-tension adjustment wheel 37. After adjustment, release the spring pin. Under the action of the spring, the pin pops out and locks the toothed pre-tension adjustment wheel 37. The radius of the spring pin 38 is the same as the width of the tooth groove to ensure the accuracy of tension adjustment.

[0057] The calf adaptive adjustment plate includes a rotating hinge 39, a lower calf plate 40, and a calf interactive shell 41. The upper end of the rotating hinge 39 is connected to the calf support plate 35, and the lower end is connected to the lower calf plate 40, realizing inward and outward rotation adjustment to adapt to people with different calf circumferences. A calf interactive shell 41 is installed on the lower calf plate 40. The calf interactive shell 41 is designed with a knob mounting groove for fixing the tightness adjustment knob. Small holes are opened on both sides for connecting nylon straps and flexible pads. The calf interactive shell 41 is designed with protrusions to accommodate four horizontal inner holes for steel wire rope routing. The other end is connected to a tightness outer cover for adjusting the tightness of the wearing on the calf side.

[0058] The beneficial effects of this invention are:

[0059] 1. This invention achieves force relief and cushioning protection for the patient's knee joint through a combination of a gas spring buffer structure, a winding rope, a cam force transmission structure, a gear transmission structure, and a leg support structure.

[0060] 2. The interactive structure on the thigh and calf sides uses a steel wire rope routing structure and an elastic outer cover to adjust the opening degree of the exoskeleton on the thigh and calf sides, so that the exoskeleton can meet the wearing requirements of users with different leg shapes.

[0061] 3. Compared to similar exoskeletons, this exoskeleton achieves force relief and cushioning for knee flexion movements in a non-powered manner. Furthermore, all related structures are made of carbon fiber, making it very lightweight and low-burden. Using this exoskeleton for rehabilitation training is safe, reliable, and yields significant rehabilitation results.

[0062] 4. Compared with similar exoskeletons, this exoskeleton uses a rope tension adjustment device to adjust the magnitude of rehabilitation assistive force, and can apply different magnitudes of buffer assistive force to patients at different stages of rehabilitation, making it highly adaptable. Attached Figure Description

[0063] Figure 1 This is an isometric view of the overall structure of the present invention.

[0064] Figure 2 This is a structural diagram of the detachable thigh wrap shell of the present invention.

[0065] Figure 3 This is a structural diagram of the adjustable outer cover of the present invention.

[0066] Figure 4 This is a structural diagram of the thigh support structure of the present invention.

[0067] Figure 5 This is a structural diagram of the buffer gas spring of the present invention.

[0068] Figure 6 This is an exploded view of the joint shaft structure of the present invention.

[0069] Figure 7 This is a structural diagram of the incompletely meshing transmission gear of the present invention.

[0070] Figure 8 This is a structural diagram of the force-transmitting cam of the present invention.

[0071] Figure 9 The force transmission cam designed in this invention is based on the knee joint torque curve.

[0072] Figure 10 This is a schematic diagram of the force transmission principle of the force transmission cam structure of the present invention.

[0073] Figure 11 This is an external view of the rotating shaft structure and the lower leg support structure of the present invention.

[0074] In the picture:

[0075] 1. Thigh-side interactive structure; 4. Separable U-shaped leg wrap shell; 5. Thigh-side elastic outer cover; 6. Thigh support shell; 7. Leg-fitting U-shaped plate one; 8. Hydraulic head; 9. Hydraulic push rod one; 10. Hydraulic push rod two; 11. Hydraulic cylinder one; 12. Hydraulic cylinder two; 13. Hydraulic terminal one; 14. Hydraulic terminal two; 42. Lower end connection hole of the separable U-shaped leg wrap shell; 43. Adjustment knob mounting slot; 44. Horizontal inner hole one; 45. U-shaped inner hole one; 46. U-shaped inner hole two; 47. Horizontal inner hole two;

[0076] 2. Knee joint pivot structure; 15. Packaging shell; 16. Gear 1; 17. Gear 2; 18. Plunger bolt; 19. Bearing; 20. Circular cam; 21. Flat washer 1; 22. Flat washer 2; 23. Hex bolt 1; 24. Hex nut 1; 25. Cover plate 1; 26. Cover plate 2; 27. Stud; 28. Hex nut 2; 29. ​​Hex bolt 2; 30. Flat washer 3; 31. Flat washer 4; 32. Gear 3; 33. Gear 4; 34. Curved cam;

[0077] 3. Lower leg support structure 35. Lower leg support plate 36. Leg fitting U-shaped plate II 37. Preload adjustment wheel 38. Spring pin 39. Hinge 40. Lower leg plate 41. Lower leg interactive shell Detailed Implementation

[0078] The present invention will now be described in further detail with reference to the accompanying drawings.

[0079] The overall isometric view of the invention is as follows Figure 1 As shown, this embodiment provides a non-powered passive rehabilitation training exoskeleton for the knee joint, which consists of three main parts: thigh interaction structure 1, knee joint pivot structure 2, and lower leg support structure 3.

[0080] The thigh interaction structure 1, the knee joint pivot structure 2, and the lower leg support structure 3 are connected sequentially from top to bottom;

[0081] The thigh interaction structure 1 is designed to fit snugly on the thigh muscle side of the human body. The U-shaped structure at the top is designed to conform to the thigh muscle to ensure wearing comfort. The thigh interaction structure 1 includes a separate thigh leg wrap shell 4 and an elastic adjustment cover 5.

[0082] like Figure 2 As shown in Figure 3, both outer shells have some internal holes perpendicular to the cross-sectional direction. The steel wire rope passes through the internal holes to connect them. The split thigh leg wrap outer shell 4 is provided with a groove to prevent the steel wire rope from being loosened. The tension adjustment knob can be adjusted freely to control the degree of opening of the exoskeleton on the thigh side, adapting to people with different leg shapes.

[0083] The lower end of the separate thigh wrap shell 4 and the thigh support shell 6 are connected by a threaded nut. The thigh support shell 6 serves as a support shell for the thigh side, such as... Figure 4As shown, a leg-fitting U-shaped plate 7 is installed on its inner side for fitting the leg skin. The material is made of lightweight carbon fiber to reduce the weight of the overall structure and thus reduce the burden on the lower limbs during use.

[0084] The outer surface of the arc-shaped plate of the split U-shaped leg wrap 4 is provided with four small circular holes arranged in a square on both sides for fixing the nylon straps and flexible padding.

[0085] The U-shaped design, along with the use of soft nylon straps and flexible padding, ensures comfortable wear. During normal wear, the U-shaped outer shell 4, located near the front of the thigh, contains four transverse inner holes. The top and bottom transverse inner holes 44 and 47 are transversely penetrating, while the two middle U-shaped inner holes 45 and 46 are U-shaped, both used for winding the steel wire rope. The upper and lower holes are used to connect the steel wire rope to the tensioning cover 5, which has two U-shaped protrusions for routing the steel wire rope. A circular groove is located on the outer side of the separate U-shaped outer shell 4 to house the steel wire rope tension adjustment knob.

[0086] The thigh-side elastic outer cover 5 has a symmetrical structure. Four holes are set on the left and right sides in a direction parallel to the surface of the structure. U-shaped protrusions are set on the outside of the four holes. The openings of the U-shaped protrusions are arranged outwards and in pairs in a U-shape for the wire rope to run.

[0087] The thigh elastic outer cover 5 is connected to the separate U-shaped leg wrap shell 4 by a steel wire rope through four symmetrical holes on both sides. When worn, it is located in the middle of the two separate U-shaped leg wrap shells 4 and covers the upper thigh.

[0088] Furthermore, the specific wiring method of the steel wire rope is as follows: a steel wire rope of appropriate length starts from the middle adjustment knob installed in the groove 43 on the separate U-shaped leg wrap shell 4. The starting point of the steel wire rope is fixed on the purchased middle adjustment knob. Then the steel wire rope is wrapped around the outside of the middle adjustment knob, and then comes out from the groove 43, passes through the small horizontal inner hole 44 at the upper end of the separate U-shaped leg wrap shell 4, reaches one end of the U-shaped hole on the upper side of the thigh side elastic outer cover 5, passes through the U-shaped hole, returns to the middle U-shaped inner hole 45 of the separate U-shaped leg wrap shell 4, passes through and exits from the second U-shaped inner hole 46, then returns to the other U-shaped hole of the thigh side elastic outer cover 5 and passes through, and finally returns to the small horizontal inner hole 47 at the lower end of the separate U-shaped leg wrap shell 4 and passes through, returning to the elastic adjustment knob in the middle of the separate U-shaped leg wrap shell 4, thus completing the wiring of the steel wire rope on the thigh side.

[0089] When it is necessary to adjust the opening degree of the thigh side exoskeleton, turn the knob clockwise to retract the steel wire rope. The length of the steel wire rope will decrease, which will cause the tension cover 5 to tighten the two separate U-shaped leg shells 4 on the left and right sides, so that the exoskeleton fits the thigh better and the overall opening degree of the thigh side structure can be adjusted.

[0090] The thigh support shell 6 has two holes 48 on its upper and lower inner sides respectively. The two holes 48 on the upper side are used to correspond to the holes 42 on the protruding structure of the inserted split U-shaped leg wrap shell 4, and are used to fix the split U-shaped leg wrap shell 4. The two holes 49 at the lower end are matched with gear 16 and gear 2 17 respectively, and are used to connect gear 16 and gear 2 17. Gear 16 and gear 2 17 are respectively set on both sides of the lower end of the split U-shaped leg wrap shell 4.

[0091] Meanwhile, the lower end of the separate thigh wrap shell 4 is also connected to a gas spring device via a threaded nut, such as Figure 5 As shown, the structure placed inside the thigh support shell 6 includes a hydraulic head 8, a hydraulic push rod 1 9, a hydraulic push rod 2 10, a hydraulic cylinder 1 11, a hydraulic cylinder 2 12, a hydraulic terminal 1 13, and a hydraulic terminal 2 14. The hydraulic head 8 has a through threaded hole in the middle for attaching a bolt to connect to the separate thigh support shell 4. A winding is then hung on top, passing over the cam below to transmit the force of the gas spring. Inside, there are two symmetrical threaded holes connecting to hydraulic push rod 1 9 and hydraulic push rod 2 10 respectively. The push rods are connected to hydraulic cylinder 1 11 and hydraulic cylinder 2 12 respectively. The hydraulic cylinders have grooves that match the push rods. Initially, the push rods are pulled out; when they are compressed inward, the air volume decreases, creating a buffering effect. The lower end connects to hydraulic terminal 1 13 and hydraulic terminal 2 14. Each terminal has a hole to accommodate a threaded nut of a certain size for connecting to the knee joint pivot structure 2.

[0092] Knee joint pivot structure 2 is based on human knee joint dimensions, such as... Figure 6 As shown, gears 16 and 17, as well as gears 32 and 33, are two pairs of incompletely meshing gears used to simulate knee joint rotation. Figure 7 As shown, it mainly undertakes the functions of shape constraint and transmission. By setting the meshing position and number of teeth of two pairs of gears, the structure can provide a rotation range of about 120° within the smooth meshing range of the gears. The remaining rotation gradually turns to the meshing limit position, and the resistance gradually increases.

[0093] Gear 16 and Gear 27 are connected by a threaded nut, a thigh support housing 6, and hydraulic terminals 13 and 24. They are identical in shape and have 6 teeth within an angle range of approximately 135°. The engagement position has a smooth curve, while the disengagement position has a sharper curve.

[0094] Gear 32 and Gear 43 have the same shape and are set with 5 teeth in an angle range of about 120°. The engagement and disengagement positions at both ends are relatively sharp. When rotated to the engagement and disengagement positions, the engagement and disengagement positions of Gear 32 and Gear 43 partially insert into the first tooth and its engagement position and the sixth tooth and its disengagement position of Gear 16 and Gear 27. After reaching the limit position, the difficulty of rotation increases, thereby increasing the rotation resistance and completing the limiting function.

[0095] Carbon fiber is selected as the material to ensure strength at the joint while meeting the requirements of lightweight design, reducing the burden on the knee joint. The 3mm tooth thickness provides a small contact space even during slight inward or outward rotation, meeting the requirements of power transmission. A smooth curve with a relatively large curvature is designed at the meshing point of gear 16 and gear 27. Figure 7 As shown, when the gear rotates to this point, the force-bearing part is in surface contact, increasing the force-bearing area and giving the structure higher strength to withstand the resistance brought by the limit. The gear disengagement point is designed with a sharp curve with a very small curvature. When the gear rotates to this point, the force-bearing part is in line contact, which will create a large reaction resistance, effectively preventing the gear from disengaging and causing the mechanism to jam. At the same time, when the human knee joint rotation angle exceeds the safe range, the joint pressure is transferred to the thigh, avoiding secondary damage to the knee joint and reminding the patient.

[0096] Two pairs of gears are placed in parallel, with a cam transmission structure in the middle, including a circular cam 20 and a curved cam 34, such as... Figure 8 As shown, the cam is designed based on the knee joint torque curve, and its torque characteristics under different loads are as follows: Figure 9 As shown, the assist curve is fitted to the relevant curve of the joint angle. Based on the human walking and leg lifting pattern, the thigh side cam is designed as a circle with a fixed radius, while the lower leg side is designed according to the knee joint torque variation characteristics to adapt to the force transmission needs under different postures.

[0097] Its force transmission mathematical model can be established, such as Figure 10 As shown, the upper side is a circular cam 20 on the thigh side, and the lower side is a curved cam 34 on the calf side. The force supply wire passes around the force transmission cam. When the knee is flexed, part of the wire attaches to the force transmission cam, and the wire length becomes shorter, causing the gas spring to compress and generate resistance. This force is regarded as a force F transmitted from the thigh side. Under the action of the curved cam 34 on the calf side with a specific curve, the rate at which the force supply wire changes with the knee joint flexion angle is changed, thereby adapting to the changing characteristics of the joint torque. Figure 9The auxiliary torque it provides to the knee joint can be expressed as (1). The radius of the circular cam 20 on the thigh side is r1 and remains constant. Based on the characteristics of torque variation of fixed stiffness, it is designed that r2 is linearly related to the sine of the joint rotation angle β. In the figure, α is the angle between the lower leg axis and the center line of the gear pair, which satisfies the relationship (2) with the knee joint rotation angle. Then the lower leg cam radius r2 is linearly related to the sine of 2α. Considering the actual size limitation, the design size is as shown in equation (3).

[0098]

[0099] Flat washers 1-21, 2-22, 3-30, and 4-31 are used to clamp the cam and gear, and the torque is transmitted by the clamping friction, thereby reducing the fatigue wear of the meshing gears. The outer side is fixed by cover plate 1-25, cover plate 2-26 and packaging shell 15 connected by two pairs of bolts and nuts, namely hex bolt 1-23, hex bolt 2-29, hex nut 1-24 and hex nut 2-28. In addition, a stud is designed between the two cover plates and double-ended bolts are used for connection and fixation to increase structural strength and make the appearance more beautiful.

[0100] Lower leg support structure 3 is strapped to the side of the lower leg, with the structure as follows: Figure 7 As shown, the structure includes a calf support plate 35, with its upper end clamped between gears 32 and 43, and connected to the rotating shaft structure 2 via a threaded nut. A leg-fitting U-shaped plate 36 is fixed to the inner side of the lower part, and a preload adjustment wheel 37 is installed on the outer side. The preload adjustment wheel 37 is connected to a winding that originates from the hydraulic head 8, passes around the circular cam 20 and the curved cam 34. When the knob is rotated, the winding contracts or expands, thereby adjusting the preload provided by the gas spring to the mechanism. A spring pin 38 is installed at the lower end of the structure via a protrusion. In operation, the spring pin is ejected by the spring, thus locking the preload adjustment wheel 37, ensuring the gas spring can correctly transmit torque. When the preload needs adjustment, the spring pin is pulled out, allowing the adjustment wheel 37 to rotate, thereby adjusting the preload to suit the rehabilitation needs of different patients or patients at different stages of rehabilitation.

[0101] The lower end is connected to a lower leg plate 40 via a hinge 39, allowing the structure to rotate freely in and out to adapt to changes in leg thickness. A lower leg interactive shell 41 is then installed at the lower end of the lower leg plate 40, which also has a cable routing hole for providing steel wire rope. The steel wire rope is then connected to a tension adjustment cover. A groove is provided on the lower leg interactive shell 41 for installing a steel wire rope routing adjustment knob to adjust the length of the steel wire rope, thereby adjusting the tightness when wearing it. The overall structure includes a similar structure on both the thigh and lower leg sides, improving the adaptability and wearing comfort of the exoskeleton.

[0102] In the above technical solution, the mechanism by which the knee joint-assisted rehabilitation training exoskeleton reduces knee joint pressure is as follows:

[0103] (1) In the initial upright state, straps and flexible pads are fixed on the interactive shells on the thigh and calf sides respectively. When wearing it, four straps are used for binding, two on the thigh and two on the calf, so that the movement of the exoskeleton can be related to the flexion and extension of the knee joint.

[0104] (2) Adjust the tension of the steel wire rope on the thigh and calf sides to make the structure fit the leg muscles better and ensure comfortable wear.

[0105] (3) Bend your knees and feel the cushioning resistance provided by the exoskeleton and the pain in your knee joint. If you feel too much resistance, you can adjust the tension of the rope around your lower leg according to your own situation to find a suitable state.

[0106] Working principle of the invention:

[0107] (1) In the initial state, first install straps and flexible pads on the thigh side fitting arc plate 7 and the calf side fitting arc plate 36, and wear it. Adjust the length of the wire rope winding so that the thigh side separate U-shaped leg wrap shell 4 and thigh elastic adjustment outer cover 5 fit the thigh better. Similarly, adjust the length of the wire rope on the calf side so that the calf interaction shell 41 fits the calf side better, ensuring wearing comfort.

[0108] (2) The force transmission cam winding starts from the hydraulic head 8, reaches the circular cam 20 and winds around it once, continues down to the curved cam 34 and winds around it once, and continues down to be tied to the preload adjustment wheel 37.

[0109] (3) After wearing, perform a small knee flexion movement. As the angle of the rotating shaft module 2 increases, more windings will adhere to the force transmission cam. However, the overall length of the windings remains unchanged during operation. Therefore, the hydraulic head 8 of the gas spring device can only be driven to move downward to ensure consistent length. At this time, the hydraulic push rod 1 9 and hydraulic push rod 2 10 will compress the air in the hydraulic cylinder 1 11 and hydraulic cylinder 2 12. The hydraulic cylinder is a closed container. After the gas in the cylinder is compressed, the pressure increases, generating resistance and storing energy to achieve buffer protection for the knee joint. When the knee joint is extended, the gas spring releases energy to achieve the assist effect.

[0110] (4) When the knee joint buffer resistance is too high, the preload adjustment wheel 37 can be rotated counterclockwise to increase the length of the winding and thus reduce the buffer resistance. Similarly, when the shaft module is loose and the buffer resistance is insufficient, the preload adjustment wheel 37 can be rotated clockwise to reduce the length of the working winding and increase the distance the gas spring is compressed, thereby increasing the buffer resistance when bending the knee and the joint assistance when extending the knee.

[0111] This invention utilizes a gas spring as a cushioning structure and a pair of cams as a force transmission structure, along with a preload adjustment device, to achieve cushioning and force relief protection for the knee joint. The entire exoskeleton structure adopts a powerless strategy, using the gas spring cushioning structure as an energy storage element. The structure is simple, safe, and reliable, with a wide adjustable range of auxiliary force, allowing for adjustment of the auxiliary torque according to the needs of different patients or different stages of rehabilitation. The interactive structure on the upper and lower leg sides can be adjusted to accommodate the needs of users with different leg shapes. The entire exoskeleton is lightweight, simple in structure, flexible in movement, highly comfortable, easy to wear, and highly adaptable.

[0112] Compared with existing knee joint rehabilitation exoskeletons, the exoskeleton of this invention adopts a non-powered, lightweight design with a simpler structure and strong adaptability. It is suitable for different stages of rehabilitation and for people of different body types. It is comfortable to wear and can effectively accelerate the rehabilitation process of knee joint patients while reducing their pain.

[0113] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the specific implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A lightweight, unpowered knee joint assistive rehabilitation training exoskeleton, characterized in that, This includes the thigh side interaction structure, knee joint pivot structure, and calf support structure connected from top to bottom; The thigh side interaction structure, knee joint pivot structure, and calf support structure are symmetrically installed on both sides of the human body, corresponding to the left and right legs respectively. The thigh-side interactive structure is used to interact with the side of the human thigh, so as to fit the thigh muscle side of the human body. The thigh-side interactive structure is provided with steel wire. By adjusting the tension of the steel wire, the opening degree of the thigh-side interactive structure can be adjusted to meet the needs of people with different leg sizes. The knee joint pivot structure is used to simulate the flexion and extension degrees of freedom of the knee joint. It rotates through two pairs of meshing gears and adjusts the passive auxiliary force through a pair of force transmission cams. The lower leg support structure is used to support the lower leg during knee flexion and extension of the knee joint pivot structure; The thigh-side interactive structure includes a separate U-shaped leg wrap shell, a thigh-side elastic outer cover, a thigh support shell, and a gas spring cushioning structure. The inner side of the split U-shaped leg wrap shell is closely attached to the outer side of the left and right thighs. The outer side of the split U-shaped leg wrap shell is provided with a protruding structure. The protruding structure is inserted into the thigh support shell. The thigh support shell is a hollowed-out rectangular structure. The separate U-shaped leg wrap shell has a cable hole, through which a steel wire rope is passed and connected to the thigh side elastic cover. The steel wire rope connects the thigh elastic cover and the two separate U-shaped leg wrap shells. The U-shaped leg wrap shell is equipped with a steel wire rope tension adjustment knob. The lower end of the separate thigh leg wrap shell is also connected to a gas spring device through a threaded nut. The detachable U-shaped leg wrap shell has two holes on its protruding structure, which are matched and connected by threaded nuts and two pairs of holes on the left and right thigh support shells. The outer surface of the detachable U-shaped leg wrap has four small circular holes arranged in a square on both sides of the arc-shaped plate, which are used to fix the nylon straps and flexible padding. The U-shaped outer surface of the detachable U-shaped leg wrap near the front of the thigh contains four transverse inner holes, namely transverse inner hole one, U-shaped inner hole one, U-shaped inner hole two and transverse inner hole two. The two horizontal inner holes, one at the top and one at the bottom, are horizontally penetrating, while the two U-shaped inner holes, one at the middle and one U-shaped inner hole, are U-shaped and are used for winding the wire rope. The upper and lower holes are used to connect the tensioning outer cover with the wire rope. The outer side of the detachable U-shaped leg wrap has a circular groove for placing the wire rope tension adjustment knob. The elastic outer cover on the thigh side has a symmetrical structure. Four holes are set on the left and right sides in a direction parallel to the surface of the structure. U-shaped protrusions are set on the outside of the four holes. The openings of the U-shaped protrusions are arranged outward and in pairs in a U-shape for the wire rope to run. The elastic thigh cover is connected to the separate U-shaped leg wrap shell by a steel wire rope through four symmetrical holes on both sides. When worn, it is located in the middle of the two separate U-shaped leg wrap shells and covers the upper thigh. The specific wiring method for the steel wire rope is as follows: the steel wire rope starts from the middle adjustment knob installed in the circular groove on the outer shell of the split U-shaped leg wrap. The starting point of the steel wire rope is fixed on the purchased middle adjustment knob. Then the steel wire rope is wrapped around the outside of the middle adjustment knob, then comes out from the circular groove, passes through the small horizontal inner hole one at the upper end of the split U-shaped leg wrap, reaches one end of the U-shaped hole on the upper side of the thigh side elastic cover, passes through the U-shaped hole, returns to the middle U-shaped inner hole one of the split U-shaped leg wrap and passes through it again, and then passes out from the second U-shaped inner hole. Then it returns to the other U-shaped hole on the thigh side elastic cover and passes through it again. Finally, it returns to the small horizontal inner hole two at the lower end of the split U-shaped leg wrap and passes through it again, returning to the elastic adjustment knob in the middle of the split U-shaped leg wrap, thus completing the steel wire rope wiring on the thigh side.

2. The lightweight, unpowered knee joint assistive rehabilitation training exoskeleton according to claim 1, characterized in that, The thigh support shell has two holes on its upper and lower inner sides respectively. The two holes on the upper side are used to correspond to the holes on the protruding structure of the inserted split U-shaped leg wrap shell for fixing the split U-shaped leg wrap shell. The two holes at the lower end are matched with gear one and gear two respectively for connecting gear one and gear two. Gear one and gear two are respectively set on both sides of the lower end of the split U-shaped leg wrap shell. The inner side of the thigh support shell is fixed to the thigh side fitting arc plate one, the thigh side fitting arc plate one fits the thigh, and the thigh side fitting arc plate one has 3 small holes on each of the left and right sides for fixing the nylon straps, and a flexible pad is pasted on the nylon straps. The gas spring buffer structure includes a hydraulic head, with hydraulic push rod one and hydraulic push rod two fixedly connected to the lower ends of the hydraulic head respectively; hydraulic push rod one is connected to hydraulic terminal one via hydraulic cylinder one; hydraulic push rod two is connected to hydraulic terminal two via hydraulic cylinder two. The top of the hydraulic head has a threaded hole that connects to the threaded hole below the shell of the split U-shaped leg through a tension threaded support. At the same time, the power supply wire is tied to the middle hole of the hydraulic head as the power supply end. The wire passes around the power transmission circular cam and the curved cam and reaches the tension adjustment knob on the lower leg side to transmit the buffer resistance of the gas spring.

3. The lightweight, unpowered knee joint assistive rehabilitation training exoskeleton according to claim 2, characterized in that, The gas spring buffer structure is installed inside the thigh support shell. Through the perforated hydraulic terminal one and hydraulic terminal two, gear one and gear two are clamped and placed on the outside, corresponding to the two small holes on the upper side of the two gears, and then connected to the two holes on the lower side of the thigh support shell. Hydraulic push rod 1 and hydraulic cylinder 1 are locked at both ends. Hydraulic cylinder 1 is completely sealed. The lower end of hydraulic cylinder 1 is connected to hydraulic terminal 1 through internal thread. Hydraulic terminal 1 has a hole that connects to a hole at the lower end of thigh support shell. The hydraulic push rod 2 and the hydraulic cylinder 2 are locked at both ends. The hydraulic cylinder 2 is completely sealed. When the hydraulic push rod 2 slides in the middle groove, it will compress air, thereby generating buffer resistance. The lower end of the hydraulic cylinder 2 is connected to the hydraulic terminal 2 through an internal thread. The hydraulic terminal 2 has a hole that connects to another hole at the lower end of the thigh support shell.

4. The lightweight, unpowered knee joint assistive rehabilitation training exoskeleton according to claim 3, characterized in that, The knee joint pivot structure includes two pairs of partially meshing gears, namely gear one and gear three, and gear two and gear four. Gear 1 and gear 3 mesh; gear 2 and gear 4 mesh. Gear 1 and Gear 2 are attached to one side of the circular cam via flat washer 1, and to the other side via flat washer 2; Gear three and gear four are attached to one side of the curved cam via flat washer four, and to the other side via flat washer three; Cover plate one and cover plate two are respectively provided on both sides of the two pairs of incompletely meshing gears, and the outer sides of cover plate one and cover plate two are covered with packaging shell; The gear one, gear two, flat washer one, circular cam, flat washer two, cover plate one, cover plate two, and packaging shell are provided with through holes at the same corresponding positions. Hex bolt one passes through the above-mentioned through holes and is fixed by hex nut one to connect the above-mentioned components together. Gear 3, Gear 4, Flat Washer 4, Curved Cam, Flat Washer 30, Cover Plate 1, Cover Plate 2, and Packaging Shell are provided with through holes at the same corresponding positions. Hexagonal Bolt 2 passes through the above-mentioned through holes and is fixed by Hexagonal Nut 2, connecting the above-mentioned components together.

5. The lightweight, unpowered knee joint assistive rehabilitation training exoskeleton according to claim 4, characterized in that, Gear 1 and Gear 2 are arranged side by side, and Gear 3 and Gear 4 are arranged side by side. The unmeshed end of each gear is a square plate structure with through holes. The through holes on Gear 1 and Gear 2 match the through holes on the lower side of the thigh support shell for connection. The through holes on gears three and four match the through holes on the lower leg support structure for connection. Gear 1 and Gear 2 have the same module and pitch circle radius, and each gear is designed to have 6 teeth. The three gears and the four gears have the same module and pitch circle radius, and each gear is designed to have 5 teeth. It provides a rotation range of approximately 120° within the smooth meshing range of the gears, enabling control of the rotation angle range and angle limit; The circular cam and the curved cam constitute a cam force transmission structure. The circular cam is a circle with a fixed radius, while the calf-side cam is designed according to requirements to adapt to the force transmission requirements in different scenarios. Since the calf-side cam is fixed in the calf support structure, it will form an angle with the circular cam during the movement of the mechanism. The angle is linearly related to the knee joint angle. Four flat pads are used to support the two pairs of meshing gears. The cam has a groove in the middle for winding the wire rope. One end of the wire rope is connected to the hydraulic head, passes around the force transmission cam, and the other end is connected to the tension adjustment knob of the lower leg. During operation, the torque can be effectively transmitted through the cam.

6. The lightweight, unpowered knee joint assistive rehabilitation training exoskeleton according to claim 3, characterized in that, The calf support structure includes a calf support plate, a rope tension adjustment wheel and spring pin, and a calf adaptability adjustment plate; The lower leg support plate is used to provide support for the lower leg side when assisting. The winding rope tension adjustment wheel and spring pin are used to adjust the tension of the winding rope, thereby adjusting the preload of the assist device. The winding rope tension adjustment wheel winds the winding rope, and the winding length is adjusted by rotation. The spring pin is used to lock the winding rope tension adjustment wheel to maintain a certain winding length. The calf adaptive adjustment plate is used to adjust the opening degree of the lower side of the calf. It is connected to the lower side of the calf support plate by a hinge. The opening degree can be adjusted by the one degree of freedom provided by the hinge, so as to adapt to the characteristic of the calf tapering downward. The uppermost part of the calf support plate has two small holes for connecting the through holes on the square plate structure of gear three and gear four. The parallel gears are connected by threaded nuts. Gear three and gear four have an inward fold at the bottom to adapt to the characteristic of the thigh tapering towards the calf. A calf-side fitting arc-shaped plate is installed on the inner side of the calf support plate. The calf-side fitting arc-shaped plate fits the calf and is fixed through small holes on the calf support plate. The lower leg support plate is provided with a slender rectangular groove that transitions to a circle. The circular groove is used to install the pretension adjustment wheel. The adjustment wheel has a hole in the center. After being installed on the outside of the lower leg support plate through the circular groove, the inner lower leg side fitting arc plate is also provided with a hole at the position opposite to the center hole of the pretension adjustment wheel. Thus, the lower leg side fitting arc plate and the pretension adjustment wheel are connected to both sides of the lower leg support plate by threaded nuts. A small boss is provided below the circular groove, and a small internal thread hole is provided in the center of the boss for placing the spring pin. A hinge is installed on the small leg support plate below the spring pin. The preload adjusting wheel and spring pin constitute the winding rope tension adjustment device; the preload adjusting wheel is installed by setting threads on the outside of the lower leg support plate. The preload adjusting wheel is used to adjust the tension of the winding rope. The preload adjusting wheel is designed with a toothed structure, and a groove is designed at the lower end for installing the spring pin.

7. The lightweight, unpowered knee joint assistive rehabilitation training exoskeleton according to claim 6, characterized in that, The calf adaptive adjustment plate includes a rotating hinge, a lower calf plate, and a calf interactive shell. The upper end of the rotating hinge is connected to the calf support plate, and the lower end is connected to the lower calf plate, enabling inward and outward rotation adjustment to accommodate people with different calf circumferences. A calf interactive shell is installed on the outside of the lower calf plate. The calf interactive shell is designed with a knob mounting slot for fixing the tightness adjustment knob, and small holes on both sides for connecting nylon straps and flexible pads. The calf interactive shell is designed with protrusions to accommodate four horizontal inner holes for steel wire cable routing. The other end is connected to a tightness adjustment cover for adjusting the tightness of the calf side.

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