Modular knee exoskeleton based on series elastic actuators

Abstract

A modular knee exoskeleton based on a series elastic actuator includes a series elastic actuator, a modular knee exoskeleton, Bowden wires, and a main control module. The series elastic actuator is connected to the modular knee exoskeleton via Bowden wires. The modular knee exoskeleton contains elastic units for cushioning and compressive energy storage during knee flexion. The main control module controls the operation of the series elastic actuator, causing the elastic units to rebound and generate assist. This invention proposes a modular knee exoskeleton system based on a series elastic actuator. During knee flexion in the wearer's gait cycle, the modular knee exoskeleton separates from the series elastic actuator, with only the elastic units in the modular knee exoskeleton providing cushioning. The series elastic actuator does not generate additional resistance for the wearer.

Description

Technical Field

[0001] This invention belongs to the field of rehabilitation medical devices, and specifically relates to a modular knee exoskeleton based on a series elastic actuator. Background Technology

[0002] Existing powered knee exoskeletons are wearable mechanical devices that assist the wearer in performing knee joint movements, based on the human limb's movement relationships and physiological structure. In use, the powered knee exoskeleton fits closely to the body, and the motor's output torque is transmitted to the knee joint via the motor shaft, reducer, and exoskeleton hardware, thereby driving knee joint rotation. As a wearable device, the powered knee exoskeleton has a direct physical coupling with the human body; therefore, safety and comfort are paramount. Current powered knee exoskeletons mostly use direct-drive motors, which suffers from poor safety and low comfort. Because the human body has direct physical contact with the exoskeleton, the lack of elastic drive mechanisms and mechanical structures reduces wearing comfort and can even cause personal injury. Furthermore, existing powered knee exoskeletons are bulky and cumbersome, with actuators that are not user-friendly, and lack flexibility to accommodate the user after sudden power-on or power-off events, resulting in stiffness. Secondly, existing knee exoskeletons often use forward and reverse motor control strategies to avoid wearer resistance to motor damping, which makes it difficult to achieve proper power separation in series elastic actuators. This leads to knee exoskeletons using series elastic drives typically employing two sets of drive lines, increasing structural complexity and power consumption. These drawbacks constitute the main reasons hindering the widespread adoption of powered knee exoskeletons. Summary of the Invention

[0003] The purpose of this invention is to provide a modular knee exoskeleton based on a series elastic actuator to solve the above-mentioned problems.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A modular knee exoskeleton based on a series elastic actuator includes a series elastic actuator, a modular knee exoskeleton, Bowden wires, and a main control module. The series elastic actuator is connected to the modular knee exoskeleton via Bowden wires. An elastic unit is provided inside the modular knee exoskeleton. The elastic unit is used for buffering and compressing energy storage during knee flexion. The main control module is used to control the operation of the series elastic actuator, causing the elastic unit to rebound and generate assistance.

[0006] Furthermore, the series flexible actuator includes a brushless DC motor, a first reduction gear, a second reduction gear, a first end-face ratchet, a second end-face ratchet, a winch, a servo gear, a servo housing, a servo motor, a first housing, and a second housing. The first housing contains a motor mounting boss and a servo motor mounting slot. The brushless DC motor is mounted in the motor mounting boss and secured with bolts. The output end of the brushless DC motor and the motor output shaft are connected by bolts. The first reduction gear is connected to the motor output shaft via a key. The servo motor is mounted in the servo motor mounting slot, and the servo motor housing is covered and secured with bolts. The servo gear is bolted to the servo motor. The bottom of the first housing has a Bowden cable mounting bracket.

[0007] The second housing is provided with a boss for abutting against the first reduction gear; the second housing is provided with a first bearing seat for placing the first tapered roller bearing, one end of the gear shaft is placed in the bearing hole of the first tapered roller bearing, and the other end is connected to the second reduction gear through a flat key;

[0008] The first end face ratchet is fixed to the first end face ratchet mounting hole on the second reduction gear by bolts, and the second end face ratchet is fixed to the second end face ratchet mounting hole on the winch by bolts.

[0009] The first outer casing is provided with a second bearing seat for placing a second tapered roller bearing. One end of the winch shaft is placed in the bearing hole of the second tapered roller bearing, and the other end is connected to the winch via a flat key. A compression spring is provided between the winch and the shoulder of the winch shaft.

[0010] Furthermore, the servo motor is equipped with a servo push rod, and the winch is connected to a winch push rod. The winch push rod includes a first pin mounting hole, a second pin mounting hole, a third pin mounting hole, and a fourth pin mounting groove. The first and second pin mounting holes form line contact with the push rod groove on the winch through mounting pins. The first housing is provided with a push rod mounting boss, which has a boss pin hole. The third pin mounting hole is connected to the boss pin hole through a pin. The servo push rod has pin mounting holes I, II, and III. The pin mounting holes I and II on the servo push rod are connected to the fourth pin mounting groove on the winch push rod through pins. The pin mounting hole III on the servo push rod is connected to the rack pin hole on the rack through a pin. The rack is placed in the rack groove on the servo motor housing and meshes with the servo gear on the servo motor output shaft. The bottom of the rack coincides with the bottom of the servo push rod.

[0011] Furthermore, the Bowden wire is installed inside the Bowden conduit, one end of which is fixed in the Bowden conduit mounting base and secured by the first conduit fixing nut and the second conduit fixing nut; one end of the Bowden wire is wound around the winch, passes through the Bowden conduit, and the other end is connected to the elastic unit.

[0012] Furthermore, the first and second housings are connected by bolts, and countersunk holes are reserved on both housings for embedding nuts and bolt heads; countersunk holes are reserved on the side of the first housing for embedding nuts when the servo housing is fixed to the first housing by bolts.

[0013] Furthermore, the modular knee exoskeleton includes a femoral fixation module, a tibial fixation module, a knee joint module, an elastic unit, a femoral module IMU, a tibial module IMU, an ankle joint module, a foot module, an upper drive block shell, and a lower drive block shell. The upper end of the knee joint module is connected to the upper drive block shell, which is connected to the femoral fixation module via a snap-fit. The elastic unit is located inside the upper drive block shell. The lower end of the knee joint module is connected to the lower drive block shell, which is connected to the tibial fixation module via a snap-fit. The lower drive block shell is connected to the ankle joint module, which is connected to the foot module via a hinge. The femoral module IMU and the tibial module IMU are respectively located on the femoral fixation module and the tibial fixation module, and are used to send data to the main control module.

[0014] Furthermore, the knee joint module includes an upper drive block, a lower drive block, an outer fixation shell, an inner fixation shell, an outer connecting rod, and an inner connecting rod. One end of the outer connecting rod and the inner connecting rod are connected to the upper drive block, and the other end is connected to the lower drive block. The outer fixation shell and the inner fixation shell are connected by threads to fix the outer connecting rod, the inner connecting rod, the upper drive block, and the lower drive block inside. The outer connecting rod and the inner connecting rod are connected by a sleeve. The upper drive block is fixed to the side of the upper drive block housing by screws, and the lower drive block is fixed to the side of the lower drive block housing by screws.

[0015] Furthermore, the elastic unit is located inside the outer shell of the upper drive block, and its bottom is mounted on the elastic unit base of the upper drive block. The piston rod is connected to the piston rod connecting block. The piston rod connecting block has a Bowden wire connector and a drive wire connector on both sides of the through hole. One end of the Bowden wire is fixed to the Bowden wire connector, and one end of the drive wire is fixed to the drive wire connector. The drive wire passes through the groove on the upper drive block and the wire channel inside the lower drive block, and the other end is fixed in the groove of the lower drive block. When the knee joint module bends, the drive wire is tensioned and drives the elastic unit to compress. When the knee joint module straightens, the drive wire returns to its original shape and the elastic unit returns to its original state.

[0016] Furthermore, the femoral fixation module is fixed to the femur with a strap, and the tibial fixation module is fixed to the tibia with a strap.

[0017] Furthermore, the Bowden wire coupling passes through a through hole in the piston rod connecting block, and its bottom has external threads. The drive wire coupling has internal threads, and the two are connected together by threads.

[0018] Compared with the prior art, the present invention has the following technical effects:

[0019] This invention proposes a modular knee exoskeleton system based on a series elastic actuator. During knee flexion in the wearer's gait cycle, the modular knee exoskeleton separates from the series elastic actuator, with only the elastic units within the modular exoskeleton providing cushioning; the series elastic actuator does not generate additional resistance for the wearer. During knee extension in the wearer's gait cycle, the modular knee exoskeleton connects to the series elastic actuator, and the brushless DC motor in the series elastic actuator actively drives the elastic units in the modular knee exoskeleton to rebound, providing walking assistance to the wearer. The modular knee exoskeleton system allows for rapid donning and disassembly, reducing donning and disassembly time, simplifying the overall structure, and reducing the weight of the exoskeleton system. Attached Figure Description

[0020] Figure 1 This is an overall diagram of a modular knee exoskeleton system based on a series elastic actuator.

[0021] Figure 2 This is an exploded planar view of a series elastic actuator.

[0022] Figure 3 This is an exploded view of the first shaft side of a series elastic actuator.

[0023] Figure 4 This is an exploded view of the second shaft side of a series elastic actuator.

[0024] Figure 5 This is a schematic diagram showing the location of the Bowden conduit mounting bracket.

[0025] Figure 6 This is a schematic diagram of a series elastic actuator.

[0026] Figure 7 This is a schematic diagram of the installation of the elastic unit.

[0027] Figure 8 This is a structural diagram of the winch push rod.

[0028] Figure 9 This is a diagram of the servo motor push rod structure.

[0029] Figure 10 It is a modular knee exoskeleton system.

[0030] Figure 11 Exploded view of the knee joint module.

[0031] in:

[0032] 1. Series elastic actuator; 2. Modular knee exoskeleton; 3. Bowden conduit; 4. Bowden wire; 5. Main control module; 6. DC brushless motor; 71. First reduction gear; 72. Second reduction gear; 81. First end face ratchet; 82. Second end face ratchet; 9. Winch; 10. Winch push rod; 11. Servo push rod; 12. Rack; 13. Servo gear; 14. Servo housing; 15. Servo; 16. First housing; 17. Second housing; 18. Stock 19. Bone fixation module; 201. Tibial fixation module; 202. Upper drive block; 203. Lower drive block; 21. Knee joint module; 22. Drive wire; 23. Elastic unit; 24. Femoral module IMU; 25. Tibial module IMU; 26. Ankle joint module; 27. Foot module; 28. Mounting boss; 29. ​​Servo mounting slot; 30. Bowden cable mounting base; 311. First cable fixing nut; 312. Second cable fixing nut; 32. Motor output shaft; 33. Boss; 34. First bearing housing; 35. First tapered roller bearing; 36. Gear shaft; 37. First end face ratchet mounting hole; 38. Second end face ratchet mounting hole; 39. Second bearing housing; 40. Second tapered roller bearing; 41. Winch shaft; 42. Compression spring; 431. Fourth pin mounting hole; 432. Second pin mounting hole; 433. Third pin mounting hole; 434. Third pin mounting hole; 44. Push rod groove; 45. Push rod mounting boss; 46. ​​Boss pin hole; 471. Pin mounting hole I; 472. Pin mounting hole II; 473. Pin mounting hole III; 48. Rack pin hole; 49. Rack groove; 501. Outer fixing shell; 502. Inner fixing shell; 511. Outer connecting rod; 512. Inner connecting rod; 52. Sleeve; 53. Upper drive block housing; 54. Lower drive block housing; 55. Elastic unit base; 56. Piston rod connecting block; 57. Bowden wire connector; 58. Drive wire connector. Detailed Implementation

[0033] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0034] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are used only for the convenience of describing the invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0035] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0036] A modular knee exoskeleton system based on a series elastic actuator includes a series elastic actuator 1, a modular knee exoskeleton 2, a Bowden conduit 3, a Bowden wire 4, and a main control module 5.

[0037] The series elastic actuator 1 includes a DC brushless motor 6, a first reduction gear 71, a second reduction gear 72, a first end face ratchet 81, a second end face ratchet 82, a winch 9, a winch push rod 10, a servo push rod 11, a rack 12, a servo gear 13, a servo housing 14, a servo 15, a first housing 16, and a second housing 17.

[0038] The modular knee exoskeleton 2 includes a femoral fixation module 18, a tibial fixation module 19, an upper drive block 201, a lower drive block 202, a knee joint module 21, a drive wire 22, an elastic unit 23, a femoral module IMU 24, a tibial module IMU 25, an ankle joint module 26, and a foot module 27.

[0039] One end of the Bowden conduit 3 is fixed to the first housing 16, and the other end is fixed to the upper drive block housing 53;

[0040] One end of the Bowden wire 4 is wound around the winch 9, passes through the Bowden wire tube 3, and the other end is connected to the elastic unit 23.

[0041] The brushless DC motor 6 is installed in the motor mounting boss 28 of the first housing 16 and is fixed by bolts;

[0042] The servo motor 15 is installed in the servo motor mounting slot 29 of the first housing 16, the servo motor housing 14 is covered, and the servo motor housing 14 is fixed by bolts;

[0043] The servo gear 13 is fixed to the servo 15 by bolts;

[0044] The bottom of the first housing 16 is provided with a Bowden conduit mounting base 30. One end of the Bowden conduit 3 is fixed in the Bowden conduit mounting base 30 and fixed by a first conduit fixing nut 311 and a second conduit fixing nut 312.

[0045] The output end of the brushless DC motor 6 and the motor output shaft 32 are connected by bolts.

[0046] The first reduction gear 71 is connected to the motor output shaft 32 via a flat key;

[0047] The second housing 17 is provided with a boss 33, which is used to abut against the first reduction gear 71 to prevent it from moving axially;

[0048] The second housing 17 is provided with a first bearing seat 34 for placing a first tapered roller bearing 35. One end of the gear shaft 36 is placed in the bearing hole of the first tapered roller bearing 35, and the other end is connected to the second reduction gear 72 through a flat key.

[0049] The first end face ratchet 81 is fixed to the first end face ratchet mounting hole 37 on the second reduction gear 72 by bolts, and the second end face ratchet 82 is fixed to the second end face ratchet mounting hole 38 on the winch 9 by bolts.

[0050] The first outer casing 16 is provided with a second bearing seat 39 for placing a second tapered roller bearing 40. One end of the winch shaft 41 is placed in the bearing hole of the second tapered roller bearing 40, and the other end is connected to the winch 9 through a flat key.

[0051] A compression spring 42 is provided between the shoulder of the winch 9 and the winch shaft 41.

[0052] The winch push rod 10 includes a first pin mounting hole 431, a second pin mounting hole 432, a third pin mounting hole 433, and a fourth pin mounting groove 434. The first pin mounting hole 431 and the second pin mounting hole 432 form line contact with the push rod groove 44 on the winch 9 by installing pins. The first outer casing 16 is provided with a push rod mounting boss 45, and the push rod mounting boss 45 has a boss pin hole 46. The third pin mounting hole 433 is connected to the boss pin hole 46 by a pin. The servo push rod 11 has pin mounting holes I 471, II 472, and III 473. The pin mounting holes I 471 and II 472 on the servo push rod 11 are connected to the fourth pin mounting groove 434 on the winch push rod 10 by a pin. The pin mounting hole III 473 on the servo push rod 11 is connected to the rack pin hole 48 on the rack 12 by a pin. The rack 12 is placed in the rack groove 49 on the servo casing 14 and meshes with the servo gear 13 on the output shaft of the servo 15. The bottom of the rack 12 coincides with the bottom of the servo push rod 11.

[0053] The first outer shell 16 and the second outer shell 17 are connected by bolts, and countersunk holes are reserved on both shells for embedding nuts and bolt heads;

[0054] The first housing 16 has a countersunk hole on its side for inserting a nut when the servo housing 14 is fixed to the first housing 16 by bolts.

[0055] The knee joint module 21 includes an outer fixing shell 501, an inner fixing shell 502, an outer connecting rod 511, and an inner connecting rod 512. One end of the outer connecting rod 511 and the inner connecting rod 512 are connected to the upper driving block 201, and the other end is connected to the lower driving block 202. The outer fixing shell 501 and the inner fixing shell 502 are fixed inside by a threaded connection. The outer connecting rod 511 and the inner connecting rod 512 are connected by a sleeve 52. The upper driving block 201 is fixed to the side of the upper driving block housing 53 by screws, and the lower driving block 202 is fixed to the side of the lower driving block housing 54 by screws.

[0056] The elastic unit 23 is disposed inside the outer shell 53 of the upper drive block and is mounted on the elastic unit base 55 of the upper drive block 201 at its bottom. The piston rod is connected to the piston rod connecting block 56. The piston rod connecting block 56 has a Bowden wire ring 57 and a drive wire ring 58 on both sides of the through hole. One end of the Bowden wire 4 is fixed to the Bowden wire ring 57, and one end of the drive wire 22 is fixed to the drive wire ring 58. The drive wire 22 passes through the groove on the upper drive block 201 and the wire channel inside the lower drive block 202, and the other end is fixed in the groove of the lower drive block 202. When the knee joint module 21 bends, the drive wire 22 is tensioned and drives the elastic unit 23 to compress. When the knee joint module 21 straightens, the drive wire 22 returns to its original shape and the elastic unit 23 returns to its original state. The femoral fixation module 18 is fixed to the femur by a strap, and the tibia fixation module 19 is fixed to the tibia by a strap.

[0057] The ankle joint module 26 and the foot module 27 are connected by a hinge;

[0058] The femoral fixation module 18 is fixed to the femur by a strap, the tibia fixation module 19 is fixed to the tibia and ankle joint by a strap, the upper drive block housing 53 is connected to the femoral fixation module 18 by a buckle, and the lower drive block housing 54 is connected to the tibia fixation module 19 by a buckle.

[0059] The foot module 27 is connected to the tibia fixation module 19 via a hinge.

[0060] The Bowden wire connector 57 passes through the through hole in the piston rod connecting block 56 and has an external thread at its bottom. The drive wire connector 58 has an internal thread, and the two are connected together by the threads.

[0061] The main control module 5 is placed on the second housing 17 to receive data from the femoral module IMU24 and the tibial module IMU25, calculate the knee joint angle, and control the movement of the DC brushless motor 6 and the servo motor 15.

[0062] This invention proposes a modular knee exoskeleton system based on advanced tandem elastic actuator technology. This system aims to significantly improve the wearer's walking efficiency and comfort through a highly integrated and intelligently controlled design. During knee flexion movements in the gait cycle, this modular knee exoskeleton exhibits a unique separation mechanism: the modular exoskeleton components and the tandem elastic actuator intelligently separate. In this process, only the carefully designed elastic units within the modular exoskeleton provide the necessary cushioning, effectively absorbing the impact force generated during knee flexion and ensuring the wearer's movements are natural and smooth. Simultaneously, the tandem elastic actuator remains silent during this phase, avoiding any unnecessary additional resistance to the wearer, thereby greatly improving wearing comfort and freedom of movement.

[0063] When the wearer enters the knee extension phase of the gait cycle, the system responds rapidly. The modular knee exoskeleton and the series elastic actuator seamlessly connect, forming a highly efficient and coordinated working whole. At this time, the high-performance brushless DC motor built into the series elastic actuator begins to function. With its precise control and powerful power output, it actively drives the elastic units in the modular knee exoskeleton to perform rapid and powerful rebound movements. This process not only provides powerful assistance to the wearer's knee extension, effectively reducing muscle burden during walking, but also ensures timely and appropriate assistance through precise torque control, allowing the wearer to experience a natural and smooth walking experience.

[0064] Furthermore, this modular knee exoskeleton system prioritizes ease of wear and practicality. The modular design allows for quick and easy connection and disconnection of components, significantly reducing the time required for donning and disassembly, improving efficiency, and making the overall exoskeleton system simpler, easier to maintain, and easier to upgrade. Simultaneously, the modular design helps reduce the overall weight of the exoskeleton system, allowing wearers to maintain greater comfort and flexibility during extended use, providing unprecedented support and assistance to various groups requiring assisted walking, such as the elderly, rehabilitation patients, or those engaged in heavy physical labor. In conclusion, this invention not only represents a technological breakthrough but also demonstrates its immense potential and value in practical applications.

[0065] For working principle, please refer to [link / reference]. Figure 6 In the initial position, the wearer is upright, and the first and second end-face ratchet wheels are disengaged. During knee flexion, the winch rotates freely, and the Bowden cable winds out of the winch. When the knee flexion ends and the knee is ready to extend, the servo rotates counterclockwise, driving the winch push rod. The first and second end-face ratchet wheels engage, the DC brushless motor starts, and drives the winch to rotate, winding the Bowden cable into the winch to assist the knee extension process. After the knee is fully extended, the DC brushless motor stops, the servo rotates clockwise, driving the winch push rod, and the first and second end-face ratchet wheels disengage.

[0066] Knee flexion process:

[0067] When the wearer performs knee flexion, the modular knee exoskeleton separates from the tandem elastic actuator. At this point, the elastic units in the modular knee exoskeleton begin to absorb the energy generated during flexion, providing assistance for subsequent extension movements.

[0068] Bowden cable gradually loosens under the action of the elastic unit, but remains connected to the winch so that power can be transmitted again when needed.

[0069] Knee extension process:

[0070] When the wearer performs knee extension movements, the modular knee exoskeleton reconnects with the tandem elastic actuators.

[0071] The main control module controls the start of the DC brushless motor based on the knee joint angle data fed back by the IMU, and tightens the Bowden cable through the reduction gear set and winch.

[0072] Bowden wires transmit power to the modular knee exoskeleton via drive wires and elastic units, causing relative movement between the upper and lower drive blocks to achieve knee extension.

[0073] During the stretching process, the elastic unit gradually releases the energy it had previously absorbed, providing the wearer with additional support.

[0074] The function of a servo motor:

[0075] The servo motor controls the movement of the rack, which in turn controls the position of the winch push rod and the servo motor push rod, thus achieving precise connection and disconnection between the winch and the Bowden line.

[0076] This plays a crucial role in the transition between knee flexion and extension, ensuring the stability and reliability of the system.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A modular knee exoskeleton based on a series elastic actuator, characterized in that, The system includes a series elastic actuator (1), a modular knee exoskeleton (2), a Bowden wire (4), and a main control module (5). The series elastic actuator (1) is connected to the modular knee exoskeleton (2) via the Bowden wire (4). The modular knee exoskeleton (2) contains an elastic unit (23). The elastic unit (23) is used for buffering and compressing energy storage during knee flexion. The main control module (5) is used to control the operation of the series elastic actuator (1), which drives the elastic unit (23) to rebound and generate assistance. The series flexible actuator (1) includes a brushless DC motor (6), a first reduction gear (71), a second reduction gear (72), a first end face ratchet (81), a second end face ratchet (82), a winch (9), a servo gear (13), a servo housing (14), a servo (15), a first housing (16), and a second housing (17). The first housing (16) is provided with a motor mounting boss (28) and a servo mounting slot (29). The brushless DC motor (6) is mounted on the motor mounting boss (71). In 28), the output end of the DC brushless motor (6) and the motor output shaft (32) are connected by bolts, and the first reduction gear (71) is connected to the motor output shaft (32) by a flat key; the servo motor (15) is installed in the servo motor mounting slot (29), the servo motor housing (14) is covered, and the servo motor housing (14) is fixed by bolts; the servo motor gear (13) is fixed to the servo motor (15) by bolts; the bottom of the first housing (16) is provided with a Bowden cable mounting seat (30); The first end face ratchet (81) is fixed to the first end face ratchet mounting hole (37) on the second reduction gear (72) by bolts, and the second end face ratchet (82) is fixed to the second end face ratchet mounting hole (38) on the winch (9) by bolts; The servo motor (15) is equipped with a servo push rod (11), and the winch (9) is connected to a winch push rod (10). The winch push rod (10) includes a first pin mounting hole (431), a second pin mounting hole (432), a third pin mounting hole (433), and a fourth pin mounting groove (434). The first pin mounting hole (431) and the second pin mounting hole (432) are connected to the push rod groove (44) on the winch (9) by installing pins. The pin mounting hole III (473) on the servo push rod (11) is connected to the rack pin hole (48) on the rack (12) by pins. The rack (12) is placed in the rack groove (49) on the servo motor housing (14) and meshes with the servo gear (13) on the output shaft of the servo motor (15). The bottom of the rack (12) coincides with the bottom of the servo push rod (11).

2. The modular knee exoskeleton based on a series elastic actuator according to claim 1, characterized in that, Bowden wire is set inside Bowden tube (3). One end of Bowden tube (3) is fixed in Bowden tube mounting base (30) and fixed by first tube fixing nut (311) and second tube fixing nut (312). One end of Bowden wire (4) is wound on winch (9), passes through Bowden tube (3), and the other end is connected to elastic unit (23).

3. A modular knee exoskeleton based on a series elastic actuator according to claim 1, characterized in that, The first housing (16) and the second housing (17) are connected by bolts, and countersunk holes are reserved on the housing for embedding nuts and bolt heads; the first housing (16) has a countersunk hole reserved on the side for embedding nuts when the servo housing (14) is fixed to the first housing (16) by bolts.

4. A modular knee exoskeleton based on a series elastic actuator according to claim 1, characterized in that, The modular knee exoskeleton (2) includes a femoral fixation module (18), a tibial fixation module (19), a knee joint module (21), an elastic unit (23), a femoral module IMU (24), a tibial module IMU (25), an ankle joint module (26), a plantar module (27), an upper drive block shell (53), and a lower drive block shell (54). The upper end of the knee joint module (21) is connected to the upper drive block shell (53), and the upper drive block shell (53) is connected to the femoral fixation module (18) by a snap-fit. The elastic unit (23) The upper drive block housing (53) is set inside the knee joint module (21); the lower end of the knee joint module (21) is connected to the lower drive block housing (54), the lower drive block housing (54) is connected to the tibial fixation module (19) by a buckle, the lower drive block housing (54) is connected to the ankle joint module (26), the ankle joint module (26) is connected to the foot module (27) by a hinge; the femoral module IMU (24) and the tibial module IMU (25) are respectively set on the femoral fixation module (18) and the tibial fixation module (19) for sending data to the main control module.

5. A modular knee exoskeleton based on a series elastic actuator according to claim 4, characterized in that, The knee joint module (21) includes an upper drive block (201), a lower drive block (202), an outer fixing shell (501), an inner fixing shell (502), an outer connecting rod (511), and an inner connecting rod (512). One end of the outer connecting rod (511) and the inner connecting rod (512) are connected to the upper drive block (201), and the other end is connected to the lower drive block (202). The outer fixing shell (501) and the inner fixing shell (502) are connected by threads to fix the outer connecting rod (511), the inner connecting rod (512), the upper drive block (201), and the lower drive block (202) inside. The outer connecting rod (511) and the inner connecting rod (512) are connected by a sleeve (52). The upper drive block (201) is fixed to the side of the upper drive block housing (53) by screws, and the lower drive block (202) is fixed to the side of the lower drive block housing (54) by screws.

6. A modular knee exoskeleton based on a series elastic actuator according to claim 5, characterized in that, The elastic unit (23) is located inside the outer shell (53) of the upper drive block and is installed on the elastic unit base (55) of the upper drive block (201) at the bottom. The piston rod is connected to the piston rod connecting block (56). The piston rod connecting block (56) has a Bowden wire ring (57) and a drive wire ring (58) on both sides of the through hole. One end of the Bowden wire (4) is fixed to the Bowden wire ring (57), and one end of the drive wire (22) is fixed to the drive wire ring (58). The drive wire passes through the groove on the upper drive block (201) and the wire channel inside the lower drive block (202). The other end is fixed in the groove of the lower drive block (202). When the knee joint module (21) bends, the drive wire (22) is tensioned and the elastic unit (23) is compressed. When the knee joint module (21) is straightened, the drive wire (22) returns to its original state and the elastic unit (23) is restored.

7. A modular knee exoskeleton based on a series elastic actuator according to claim 6, characterized in that, The femoral fixation module (18) is fixed to the femur by a strap, and the tibial fixation module (19) is fixed to the tibia by a strap.

8. A modular knee exoskeleton based on a series elastic actuator according to claim 7, characterized in that, Bowden wire connector (57) passes through the through hole in piston rod connector (56) and has external threads at its bottom. Drive wire connector (58) has internal threads, and the two are connected together by threads.

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