Pneumatic muscle four-bar linkage variable instantaneous center lower limb rehabilitation exoskeleton and impedance training method

Abstract

The invention belongs to the technical field of power-assisted robots, and particularly relates to a pneumatic muscle four-bar linkage variable instantaneous center lower limb rehabilitation exoskeleton and an impedance training method. The exoskeleton comprises a waist fixing piece, a hip joint assembly, a knee joint assembly and a sole assembly. The knee joint assembly comprises a four-connecting-rod variable instantaneous center structure, first to fourth connecting rods and the like form a parallelogram mechanism, and the parallelogram mechanism is matched with the thigh pneumatic muscle assembly for driving, so that the instantaneous center track of the knee joint is matched with the physiological track of a human body, and man-machine slippage is reduced. The hip joint assembly is hinged through a hip-leg plate and driven by a hip joint pneumatic muscle assembly, and the sole assembly comprises an elastic connecting structure. The invention further provides a variable instantaneous center knee joint track obtaining method, and the structure size matched with the human body is obtained by establishing a kinematics system and optimizing parameters. According to the impedance training method, safe and effective flexion and extension impedance training is achieved based on pneumatic muscle pressure dynamic adjustment. The exoskeleton has good motion coordination and safety, and has wide applicability.

Description

Technical Field

[0001] The present invention belongs to the technical field of power-assisted robots, and in particular relates to a pneumatic muscle four-link variable instantaneous heart lower limb rehabilitation exoskeleton and an impedance training method. Background Art

[0002] A lower limb exoskeleton is a wearable robot designed based on the bionics of human movement. Through the integration of mechanical structure and drive device, it is adapted to the joints of the lower limbs of the human body and can provide the wearer with functions such as movement assistance, load bearing, function enhancement or rehabilitation treatment.

[0003] In terms of driving mode, traditional lower limb exoskeletons are mostly driven by motors or hydraulics. Although this type of driving mode can provide greater power, the system is bulky, has a slow response speed, and it is difficult to simulate the compliance characteristics of human muscles. The public invention patent application "An Antagonistic Pneumatic Muscle Lower Limb Powered Exoskeleton" (CN115415997A) realizes antagonistic pneumatic muscle driving of the hip joint, knee joint, and ankle joint, but it cannot accurately match the physiological instantaneous center trajectory of the human knee joint movement in different motion states, and there are deficiencies in joint movement control. When wearing a lower limb exoskeleton for exercise, if a fixed axis knee joint mechanism is used, it will cause poor coordination between the human and the machine's knee joints, which will not only affect the human gait, but also aggravate the wear of the exoskeleton's knee joints. Long-term use may even cause joint pain and injury, affecting the patient's rehabilitation effect. Summary of the Invention

[0004] The present invention aims to provide a pneumatic muscle four-link variable instantaneous heart lower limb rehabilitation exoskeleton and impedance training method to solve the problems of poor knee joint coordination between man and machine, and relative slippage and dislocation between the exoskeleton and the human body.

[0005] In order to achieve the above-mentioned object, one aspect of the present invention is to provide a technical solution: a pneumatic muscle four-link variable instantaneous heart lower limb rehabilitation exoskeleton, comprising a waist fixing device, a hip joint assembly connected to the waist fixing device, a knee joint assembly connected to the knee joint assembly, and a foot assembly connected to the knee joint assembly, wherein: The knee joint assembly includes a hip-knee plate, a four-link variable instant center structure constituting the knee joint, and a calf connecting rod. The hip-knee plate and the four-link variable instant center structure are equipped with a thigh pneumatic muscle assembly for driving the knee joint movement. The knee joint four-bar variable instant center structure includes a first link, two second links, two third links, two fourth links, a first driving shaft, a second driving shaft, a first driven shaft, a second driven shaft and a third driven shaft. The third link is arranged in a V shape, the calf connecting rod is connected to the third link, the two second links are parallel, the two third links are parallel, and the two fourth links are parallel. One end of the third link is rotatably connected to one end of the second link through the first driving shaft, the end of the third link away from the first driving shaft is rotatably connected through the second driving shaft, the middle part of the third link and one end of the fourth link are rotatably connected through the first driven shaft, the first link, the ends of the two fourth links away from the first driven shaft and the bottom of the hip-knee board are rotatably connected through the second driven shaft, the bottom of the hip-knee board and the end of the second link close to the hip-knee board and away from the first driving shaft are rotatably connected through the third driven shaft, and the end of the second link away from the hip-knee board and away from the first driving shaft is rotatably connected to the first link; The sole assembly is detachably connected to the calf connecting rod.

[0006] The working principle and beneficial effects of this solution are as follows: when the thigh pneumatic muscle assembly is in motion, the driving force is transmitted to the four-bar variable instant center structure through the first drive shaft and the second drive shaft. Since the two second links are parallel, the V-shaped link at the upper end of the calf connecting rod is parallel to the third link, and the two fourth links are parallel, and the first link, the second link, the third link and the fourth link form a parallelogram, a parallelogram motion mechanism is formed, and each link rotates in coordination around the first driven shaft, the second driven shaft and the third driven shaft. During the movement, the instant center position of the knee joint is dynamically adjusted as the posture of the four-bar variable instant center structure changes, and the instant center trajectory is highly consistent with the physiological instant center trajectory of the natural movement of the human knee joint, realizing the bionic flexion and extension movement of the knee joint. At the same time, the third link is connected through the second drive shaft, which further enhances the stability and synchronization of the motion transmission.

[0007] The four-link variable instantaneous center structure can dynamically adjust the position of the rotation center during knee joint bending, so that the instantaneous center of the knee joint changes with the dynamic movement and accurately matches the physiological instantaneous center trajectory of the human knee joint, reducing the relative slip and dislocation between the exoskeleton and the human body, greatly improving movement coordination and comfort, and reducing the risk of joint wear or secondary injury during long-term use. (2) Antagonistic pneumatic muscles as driving elements have similar soft characteristics and damping effects as biological muscles, which can absorb impact vibration while providing assistance. Compared with rigid motor drive, the present invention has lower mechanical impedance and better safety. At the same time, the drive of the hip joint and knee joint is independently controllable, and the drive torque can be accurately adjusted according to gait requirements to adapt to various sports scenes such as walking, going up and downhill. The instantaneous center curve after the pneumatic muscle is combined with the four-link variable instantaneous center structure has a high degree of fit with the ideal instantaneous center curve of the human knee joint, effectively reducing the joint pain and damage that may be caused by long-term use and enhancing the patient's rehabilitation effect. Optionally, the hip joint assembly includes a hip-leg plate No. 1 and a hip-leg plate No. 2, and hip-leg plate No. 1 and hip-leg plate No. 2 are installed with hip joint pneumatic muscle components for driving hip joint movements, and the lower end of the hip-leg plate No. 1 is hinged to the upper end of the hip-leg plate No. 2; the plantar assembly includes an ankle-knee connecting plate, an elastic component and a plantar plate, and the ankle-knee connecting plate is connected to the plantar plate through the elastic component; a number of through holes are provided on the hip-knee plate, the hip-leg plate No. 2 and the calf connecting rod, and a linear groove is provided on the ankle-knee connecting plate, the upper end of the hip-knee plate is detachably connected to the lower end of the hip-leg plate No. 2, and the lower end of the calf connecting rod is detachably connected to the ankle-knee connecting plate.

[0008] Optionally, the thigh pneumatic muscle assembly includes knee joint pneumatic muscle No. 1 and knee joint pneumatic muscle No. 2, and fisheye joints are provided at both ends of knee joint pneumatic muscle No. 1 and knee joint pneumatic muscle No. 2. The top ends of knee joint pneumatic muscle No. 1 and knee joint pneumatic muscle No. 2 are hinged to the upper end of the hip knee plate through the fisheye joint, and the bottom ends of knee joint pneumatic muscle No. 1 and knee joint pneumatic muscle No. 2 are hinged to the first drive shaft and the second drive shaft respectively through the fisheye joint.

[0009] Optionally, the knee joint assembly is provided with a knee joint coupling, a knee joint angle encoder and a limit link, the knee joint angle encoder is provided at the connection between the first link and the second link, the knee joint angle encoder rotates synchronously with the second link through the knee joint coupling, one end of the limit link is fixedly connected to the hip knee plate, and the other end is fixedly connected to the first link; a limit block is fixedly provided on the first link, the limit block extends to above the fourth link, and a limit sleeve is provided on the fisheye joint connecting the knee joint No. 1 pneumatic muscle and the first drive shaft.

[0010] Optionally, the knee joint assembly is provided with a hip-knee fixing part and a calf fixing part, a plurality of through holes are provided on the hip-leg plate No. 1, the hip-knee plate and the calf connecting rod, a straight groove is provided on the waist fixing part, the hip-knee fixing part and the calf fixing part, the hip-knee plate is detachably connected to the waist fixing part, the hip-knee plate is detachably connected to the hip-knee fixing part, and the calf connecting rod is detachably connected to the calf fixing part.

[0011] Optionally, the hip joint pneumatic muscle assembly includes hip joint pneumatic muscle No. 1 and hip joint pneumatic muscle No. 2, and both ends of hip joint pneumatic muscle No. 1 and hip joint pneumatic muscle No. 2 are provided with fisheye joints, and the top ends of hip joint pneumatic muscle No. 1 and hip joint pneumatic muscle No. 2 are hinged to the upper end of hip leg plate No. 1 through the fisheye joint, and the bottom ends of hip joint pneumatic muscle No. 1 and hip joint pneumatic muscle No. 2 are hinged to the upper end of hip leg plate No. 2 through the fisheye joint.

[0012] Optionally, the hip joint assembly is provided with a hip joint coupling and a hip joint angle encoder. The hip joint coupling and the hip joint angle encoder are arranged at the hinge point between the lower end of the hip-leg plate No. 1 and the upper end of the hip-leg plate No. 2. The hip joint angle encoder rotates synchronously with the hip-leg plate No. 2 through the hip joint coupling.

[0013] Optionally, the hip joint assembly is provided with an adjustment belt, which is detachably connected to the hip-leg plate No. 1; the waist fixing member is provided with two left-right symmetrical C-shaped members, and the waist fixing member is provided with a waist adjustment plate, and one end of the two C-shaped members is detachably connected to the waist adjustment plate.

[0014] Optionally, the elastic component includes a slip ring, a pneumatic telescopic spring, a coil spring, an ankle joint hinge seat, a spring mounting seat and a plantar connecting plate, a linear groove is provided on the plantar connecting plate, the slip ring is slidingly connected to the ankle-knee connecting plate, the ankle-knee connecting plate is hinged to the ankle joint hinge seat, the ankle joint hinge seat is rotatably connected to the spring mounting seat, the spring mounting seat is detachably connected to the plantar connecting plate, the plantar connecting plate is fixedly connected to the plantar plate, the coil spring is coaxially sleeved on the outside of the pneumatic telescopic spring, one end of the pneumatic telescopic spring and the coil spring is hinged to the slip ring, and the end of the pneumatic telescopic spring and the coil spring away from the slip ring is hinged to the spring assembly mounting seat.

[0015] Another aspect of the present invention is to provide a method for performing impedance training using the pneumatic muscle four-link variable instantaneous heart lower limb rehabilitation exoskeleton, comprising: Read the preset training program parameters and initially inflate both the knee joint No. 1 pneumatic muscle and the knee joint No. 2 pneumatic muscle to the safety pressure P0; The control unit collects the angle and angular velocity of the knee joint in real time. If it detects that the knee joint is moving in the direction of flexion, the control unit increases the pressure of the knee joint's No. 2 pneumatic muscle P2 to the target pressure, while maintaining the pressure of the knee joint's No. 1 pneumatic muscle at a safe pressure P0 or slightly below the target pressure. The specific inflation volume is dynamically adjusted according to a linear mapping. When the knee joint angle approaches the maximum flexion angle, P2 drops back to P0 to avoid excessive resistance at the end. If it is detected that the knee joint is moving in the extension direction, the control unit will increase the pressure of the knee joint No. 1 pneumatic muscle P1 to the target pressure, and maintain the pressure of the knee joint No. 2 pneumatic muscle at P0 or slightly below the target pressure. The specific inflation volume is dynamically adjusted according to the linear mapping, and gradually reduced to P0 when the knee joint angle approaches the initial angle; After training, the controller will exhaust gas steadily to P0 or ambient pressure to release the impedance state. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is an overall schematic diagram of a pneumatic muscle four-link variable instantaneous heart lower limb rehabilitation exoskeleton according to an embodiment of the present invention; Figure 2Schematic diagram of the knee joint assembly of the pneumatic muscle four-link variable instantaneous heart lower limb rehabilitation exoskeleton in an embodiment of the present invention; Figure 3 Schematic diagram of the four-link instantaneous center structure of the pneumatic muscle four-link instantaneous center lower limb rehabilitation exoskeleton in an embodiment of the present invention; Figure 4 A comparison diagram of the instantaneous center trajectory curve of the knee joint of the pneumatic muscle four-link variable instantaneous center lower limb rehabilitation exoskeleton in an embodiment of the present invention and the ideal instantaneous center trajectory curve of the human knee joint; Figure 5 Schematic diagram of the operation of the knee joint assembly from -60° to 0° of the pneumatic muscle four-link variable instantaneous heart lower limb rehabilitation exoskeleton in an embodiment of the present invention; Figure 6 Schematic diagram of the hip joint assembly of the pneumatic muscle four-link variable instantaneous center lower limb rehabilitation exoskeleton in an embodiment of the present invention; Figure 7 Schematic diagram of the hip joint connection of the pneumatic muscle four-link variable instantaneous heart lower limb rehabilitation exoskeleton in an embodiment of the present invention; Figure 8 Schematic diagram of the waist fixing part of the pneumatic muscle four-link variable instantaneous heart lower limb rehabilitation exoskeleton in an embodiment of the present invention; Figure 9 Schematic diagram of the plantar assembly of the pneumatic muscle four-link variable-speed lower limb rehabilitation exoskeleton in an embodiment of the present invention. DETAILED DESCRIPTION

[0017] The following is further described in detail through specific implementation methods: The symbols in the drawings of the specification include: hip joint assembly 1, hip-leg plate No. 1 11, hip-leg plate No. 2 12, hip joint pneumatic muscle No. 1 121, hip joint pneumatic muscle No. 2 122, hip joint coupling 13, hip joint angle encoder 14, cross roller bearing 15, gasket 16, waist fixing part 17, waist adjustment plate 171, C-shaped part 172, adjustment belt 18, knee joint assembly 2, hip-knee plate 21, knee joint pneumatic muscle No. 1 211, knee joint pneumatic muscle No. 2 212, fisheye joint 213, four-bar variable instantaneous center structure 22, first connecting rod 221, second connecting rod 222, third connecting rod 22 3. Fourth connecting rod 224, first driving shaft 225, second driving shaft 226, first driven shaft 227, second driven shaft 228, third driven shaft 229, calf connecting rod 23, limiting connecting rod 24, connecting aluminum column No. 1 241, connecting aluminum column No. 2 242, limiting block 243, limiting sleeve 244, knee joint coupling 25, knee joint angle encoder 26, hip-knee fastener 27, calf fastener 28, plantar assembly 3, ankle-knee connecting plate 31, slip ring 32, pneumatic telescopic spring 33, coil spring 34, ankle joint hinge seat 35, spring mounting seat 36, plantar connecting plate 37, plantar plate 38.

[0018] Example This embodiment is basically as Figure 1 As shown: a pneumatic muscle four-link instantaneous center lower limb rehabilitation exoskeleton and an impedance training method, wherein the pneumatic muscle four-link instantaneous center lower limb rehabilitation exoskeleton includes a waist fixing part 17, the waist fixing part 17 is connected to a hip joint assembly 1, the hip joint assembly 1 is connected to a knee joint assembly 2, and the knee joint assembly 2 is connected to a plantar assembly 3.

[0019] like Figure 2 As shown, the knee joint assembly 2 includes a hip-knee plate 21, a four-bar variable instant center structure 22 constituting the knee joint, and a calf connecting rod 23. A thigh pneumatic muscle assembly for driving the knee joint movement is installed on the hip-knee plate 21 and the four-bar variable instant center structure 22. The thigh pneumatic muscle assembly includes knee joint No. 1 pneumatic muscle 211 and knee joint No. 2 pneumatic muscle 212. Both ends of the knee joint No. 1 pneumatic muscle 211 and the knee joint No. 2 pneumatic muscle 212 are provided with fisheye joints 213.

[0020] like Figure 3As shown, the four-bar variable instant center structure 22 of the knee joint includes a first link 221, two second links 222, two third links 223, two fourth links 224, a first drive shaft 225, a second drive shaft 226, a first driven shaft 227, a second driven shaft 228, and a third driven shaft 229. The third link 223 is arranged in a V-shape, with the angle between the two arms of the V-shaped third link 223 ranging from 120° to 160°. In this embodiment, the angle between the two arms of the V-shaped third link 223 is set to 135°. The calf connecting rod 23 is integrally formed with the third link 223 near the hip and knee plate 21. The two second links 222 are parallel, the two third links 223 are parallel, and the two fourth links 224 are parallel, forming a parallelogram motion mechanism. One end of the third link 223 is rotationally connected to one end of the second link 222 through the first drive shaft 225, and the end of the third link 223 away from the first drive shaft 225 is rotationally connected through the second drive shaft 226. The middle part of the third link 223 and one end of the fourth link 224 are rotationally connected through the first driven shaft 227. The first link 221, the ends of the two fourth links 224 away from the first driven shaft 227 and the bottom of the hip-knee board 21 are rotationally connected through the second driven shaft 228. The bottom of the hip-knee board 21 and the end of the second link 222 close to the hip-knee board 21 and away from the first drive shaft 225 are rotationally connected through the third driven shaft 229. The end of the second link 222 away from the hip-knee board 21 and away from the first drive shaft 225 is rotationally connected to the first link 221. The connections between the first drive shaft 225, the second drive shaft 226, the first driven shaft 227, the second driven shaft 228, and the third driven shaft 229 and the four-link are equipped with flanged bearings to provide support and prevent the four-link from shifting during movement. The four-link variable instantaneous center structure 22 dynamically adjusts the position of its center of rotation during knee flexion, ensuring that the exoskeleton's instantaneous center of rotation precisely aligns with the trajectory of the human knee's instantaneous center of rotation. This allows the exoskeleton to rotate synchronously with the user's knee during movement, closely matching the movement of the human joint, whether in standing support or walking swing.

[0021] like Figure 2As shown, the top ends of knee joint pneumatic muscle No. 1 211 and knee joint pneumatic muscle No. 2 212 are hinged to the upper end of the hip-knee plate 21 via a fisheye joint 213. The bottom end of knee joint pneumatic muscle No. 1 211 is hinged to the first drive shaft 225 via a fisheye joint 213, and the bottom end of knee joint pneumatic muscle No. 2 212 is hinged to the second drive shaft 226 via a fisheye joint 213. By flexing the left knee joint pneumatic muscle No. 1 211 and extending the right knee joint pneumatic muscle No. 2 212, the calf connecting rod 23 swings leftward relative to the four-bar variable instantaneous center structure 22 to achieve knee flexion. Conversely, by extending the left knee joint pneumatic muscle No. 1 211 and flexing the right knee joint pneumatic muscle No. 2 212, the calf connecting rod 23 swings rightward to achieve knee extension.

[0022] like Figure 3 As shown, the knee joint assembly 2 is provided with a limit link 24, a knee joint coupling 25 and a knee joint angle encoder 26. The limit link 24 includes a No. 1 connecting aluminum column 241 and a No. 2 connecting aluminum column 242. One end of the No. 1 connecting aluminum column 241 and the No. 2 connecting aluminum column 242 is fixedly connected to the hip-knee plate 21, and the end of the No. 1 connecting aluminum column 241 and the No. 2 connecting aluminum column 242 away from the hip-knee plate 21 is fixedly connected to the first connecting rod 221. The provision of the No. 1 connecting aluminum column 241 and the No. 2 connecting aluminum column 242 can effectively prevent the limit link 24 from being loosely connected to the first connecting rod 221, causing the limit link 24 to rotate relative to the first connecting rod 221 and affect the limiting effect. The knee joint angle encoder 26 is provided at the connection point between the first connecting rod 221 and the second connecting rod 222. The knee joint angle encoder 26 rotates synchronously with the second connecting rod 222 through the knee joint coupling 25. The knee joint angle encoder 26 enables the four-bar variable instantaneous center structure 22 of the knee joint to collect the movement angle of the second link 222 relative to the hip-leg plate No. 2 12 during movement, and then calculate the rotation angle of the calf through kinematic analysis, so that motion control can be performed through the dynamic control algorithm. A limit block 243 is fixed on the first link 221, and the limit block 243 extends above the fourth link 224. A limit sleeve 244 is provided on the fisheye joint 213 connecting the knee joint No. 1 pneumatic muscle 211 and the first drive shaft 225. The limit block 243 limits the movement trajectory of the third link 223 away from the hip-knee plate 21, thereby limiting the movement trajectory of the second drive shaft 226. The limit sleeve 244 limits the movement trajectory of the knee joint No. 1 pneumatic muscle 211, thereby limiting the movement trajectory of the first drive shaft 225, preventing excessive bending or extension of the knee joint and ensuring safe use.

[0023] like Figure 6 、 Figure 8As shown, the hip joint assembly 1 includes a hip-leg plate 11 and a hip-leg plate 2 12. Hip-leg plate 11 and hip-leg plate 2 12 are mounted with hip joint pneumatic muscle assemblies for driving hip joint movement. The lower end of hip-leg plate 11 is hingedly connected to the upper end of hip-leg plate 2 12. The foot assembly 3 includes an ankle-knee connecting plate 31, an elastic component, and a foot plate 38. The ankle-knee connecting plate 31 and foot plate 38 are connected via the elastic component. The hip-knee plate 21, the second hip-leg plate 12, and the calf connecting rod 23 are provided with a plurality of through-holes, and the ankle-knee connecting plate 31 is provided with a linear slot. The upper end of the hip-knee plate 21 is detachably connected to the lower end of the second hip-leg plate 12, and bolts are passed through the through-holes of the hip-knee plate 21 and the second hip-leg plate 12 to lock the connection, thereby connecting the hip joint assembly 1 to the knee joint assembly 2. The through-holes at different positions on the hip-knee plate 21 and the second hip-leg plate 12 can be aligned to adjust the length of the thigh. The lower end of the calf connecting rod 23 is detachably connected to the ankle-knee connecting plate 31, and bolts are passed through the through-holes of the calf connecting rod 23 and the linear slots of the ankle-knee connecting plate 31 to lock the connection, thereby connecting the plantar assembly 3 to the knee joint assembly 2. The through-holes of the calf connecting rod 23 and the linear slots of the ankle-knee connecting plate 31 can be aligned to allow the bolts to slide in the linear slots and lock in the appropriate position, allowing the plantar assembly 3 to be adaptively adjusted according to the wearer's body shape.

[0024] like Figure 6 As shown, the hip joint pneumatic muscle assembly includes hip joint pneumatic muscle No. 1 121 and hip joint pneumatic muscle No. 2 122. Both ends of hip joint pneumatic muscle No. 1 121 and hip joint pneumatic muscle No. 2 122 are provided with fisheye joints 213. The top ends of hip joint pneumatic muscle No. 1 121 and hip joint pneumatic muscle No. 2 122 are hinged to the upper end of hip-leg plate No. 1 1 through the fisheye joint 213, and the bottom ends of hip joint pneumatic muscle No. 1 121 and hip joint pneumatic muscle No. 2 122 are hinged to the upper end of hip-leg plate No. 2 12 through the fisheye joint 213. By stretching the left hip joint No. 1 pneumatic muscle 121 and flexing the right hip joint No. 2 pneumatic muscle 122, the hip-leg No. 2 plate 12 is swung to the right relative to the hip-leg No. 1 plate 11, driving the thigh to rise; conversely, by flexing the left hip joint No. 1 pneumatic muscle 121 and stretching the right hip joint No. 2 pneumatic muscle 122, the hip-leg No. 2 plate 12 is swung to the left relative to the hip-leg No. 1 plate 11, driving the thigh to fall.

[0025] like Figure 7As shown, the hip joint assembly 1 is provided with a hip joint coupling 13 and a hip joint angle encoder 14. The hip joint coupling 13 and the hip joint angle encoder 14 are respectively arranged on both sides of the outer hinge point of the lower end of the hip leg plate No. 1 1 and the upper end of the hip leg plate No. 2 12. The hip joint angle encoder 14 rotates synchronously with the hip leg plate No. 2 12 through the hip joint coupling 13. The hip joint angle encoder 14 is used to collect the relative rotation angle between the hip leg plate No. 1 11 and the hip leg plate No. 2 12, and read the angle in real time. A cross roller bearing 15 is provided between the hip leg plate No. 1 11 and the hip leg plate No. 2 12. The cross roller bearing 15 is coaxially connected to the hip joint coupling 13. Gaskets 16 are provided on both sides of the cross roller bearing 15 to prevent parts from interfering with each other and ensure smooth movement.

[0026] like Figure 1 As shown, the knee joint assembly 2 is provided with a hip-knee fixing part 27 and a calf fixing part 28, a plurality of through holes are provided on the hip-leg plate No. 1 11, the hip-knee plate 21 and the calf connecting rod 23, and a linear groove is provided on the waist fixing part 17, the hip-knee fixing part 27 and the calf fixing part 28. The hip-leg plate No. 1 11 and the waist fixing part 17 are detachably connected by bolts passing through the through holes on the hip-leg plate No. 1 11 and the linear groove on the waist fixing part 17, and the bolts can slide up and down along the linear groove to determine the appropriate position to lock the hip-leg plate No. 1 11 and the waist fixing part 17, so as to realize the precise adjustment of the fixed position of the waist fixing part 17; the hip-knee plate 21 and the hip-knee fixing part The fixing member 27 is detachably connected by bolts passing through the through-holes in the hip-knee plate 21 and locking with the linear grooves in the hip-knee fixing member 27. The bolts can slide up and down along the linear grooves to determine the appropriate position to lock the hip-knee plate 21 and the hip-knee fixing member 27, allowing precise adjustment of the fixed position of the hip-knee fixing member 27. The calf connecting rod 23 and the calf fixing member 28 are detachably connected by bolts passing through the through-holes in the calf connecting rod 23 and locking with the linear grooves in the calf fixing member 28. The bolts can slide up and down along the linear grooves to determine the appropriate position to lock the calf connecting rod 23 and the calf fixing member 28, allowing precise adjustment of the fixed position of the calf fixing member 28. The hip joint assembly 1 is provided with an adjustable waist belt 18, which is detachably connected by passing through the through-holes in the hip-knee plate 11. The waist fixing part 17 is configured as two left-right symmetrical C-shaped parts 172, and the waist fixing part 17 is provided with a waist adjustment plate 171. One end of the two C-shaped parts 172 is detachably connected to the waist adjustment plate 171. A plurality of through holes are provided at the connection between the waist adjustment plate 171 and the two C-shaped parts 172. The waist adjustment plate 171 and the two C-shaped parts 172 are locked and connected by bolts passing through the through holes. The bolts can be passed through different through holes to adjust the width of the waist fixing part 17 to adapt to the hip width of wearers of different body shapes.

[0027] like Figure 8As shown, the elastic component includes a slip ring 32, a pneumatic telescopic spring 33, a coil spring 34, an ankle joint hinge seat 35, a spring mounting seat 36 and a plantar connecting plate 37. A linear groove is provided on the plantar connecting plate 37. The slip ring 32 is slidably connected to the ankle-knee connecting plate 31. The ankle-knee connecting plate 31 is hinged to the ankle joint hinge seat 35. The ankle joint hinge seat 35 is rotatably connected to the spring mounting seat 36. The spring mounting seat 36 is detachably connected to the plantar connecting plate 37. The spring mounting seat 36 is detachably connected to the plantar connecting plate 37. The spring mounting seat 36 is detachably connected to the plantar connecting plate 37. The linear slots 36 and 37 of the sole connecting plate 37 are locked together. The linear slots on the sole connecting plate 37 can be adjusted with bolts to adjust the locking position, allowing the wearer to adjust the foot to their leg length. The sole connecting plate 37 is fixedly connected to the sole plate 38. The coil spring 34 is coaxially sleeved on the outside of the pneumatic telescopic spring 33. One end of the pneumatic telescopic spring 33 and the coil spring 34 is hinged to the slip ring 32. The ends of the pneumatic telescopic spring 33 and the coil spring 34 away from the slip ring 32 are hinged to the spring assembly mounting seat. This structure provides flexible elastic support for the sole assembly 3, allowing the sole plate 38 to swing naturally with the movement of the lower leg within a set angle range. The sole plate 38 serves as the bearing surface in contact with the ground, transmitting the forces generated during walking to the entire exoskeleton structure.

[0028] The driving mode adopted by the present invention is the pneumatic muscle driver antagonistic drive, which can meet the needs of human walking. The flexion and extension degrees of freedom of the hip joint and knee joint are set as the driving degrees of freedom, and the flexion and extension of the ankle joint are set as the passive degrees of freedom. The rotation angle range of the hip joint in the sagittal plane is limited to -30° to 30°. The rotation angle range of the knee joint in the sagittal plane is -60° to 0°. The operation diagram of the four-bar variable instantaneous center structure 22 of the knee joint is shown in FIG. Figure 5 The rotation angle of the ankle joint in the sagittal plane ranges from -25° to 25°.

[0029] The four-link variable instantaneous center knee exoskeleton includes an independent control unit, which is mounted on a waist fixture 17. The control unit controls the inflation and deflation of the hip joint pneumatic muscle assembly and the thigh pneumatic muscle assembly through electromagnetic valves, thereby achieving independent drive control of the hip and knee joint movements. Hip joint angle encoders 14 and knee joint angle encoders 26 are provided at the hip and knee joints to detect changes in joint angles or lengths of pneumatic muscles. The control unit runs a closed-loop control algorithm based on the feedback signals of the hip joint angle encoder 14 and the knee joint angle encoder 26 to dynamically adjust the air pressure and tension of the pneumatic artificial muscles, thereby achieving precise power output. At the same time, the control unit presets a safety threshold. When it detects that the joint angle or torque is close to exceeding the safety range, the limit protection mechanism is automatically triggered to limit the output of the pneumatic muscle or lock the joint movement to ensure safe use.

[0030] The components of the present invention are primarily constructed of carbon fiber, while the four-bar variable center structure 22 is constructed of aluminum alloy. Pneumatic muscles serve as the actuator, resulting in a relatively light overall machine. The pneumatic muscles, acting as actuators, utilize air pressure to control their contraction, operating in a manner similar to human muscle, resulting in smooth, muscle-like movement. Furthermore, since the pneumatic muscles are woven from a special rubber material, they offer flexibility, safety, light weight, and high output. Compared to cold cylinders and motors, they are more suitable for applications involving close human contact. The components of the present invention are independently controlled, so the movement of each joint is solely driven by the expansion and contraction of the pneumatic muscles, without interfering with each other's movements. This facilitates accurate control of the present invention, resulting in smooth overall movement, high precision, and excellent stability.

[0031] This invention utilizes a detachable, modular, and adjustable mechanical design. Key dimensions such as hip width, thigh, and calf length can be adjusted to the user's body type, allowing the same exoskeleton to accommodate users of varying heights and leg lengths. Precise alignment ensures that the axes of the exoskeleton's joints are coaxial with the user's own joints, ensuring a correct and unbiased force transmission path. This improved human-machine alignment makes the training process more natural and effective, meeting the rehabilitation training needs of multiple users and possessing broad applicability.

[0032] The method for obtaining the variable instantaneous center knee joint trajectory by using the above-mentioned four-bar variable instantaneous center structure 22 of the knee joint comprises the following specific steps: S1: Establishment of artificial knee joint kinematic system; S2: Establish the ideal instantaneous center trajectory equation of the human knee joint based on motion constraints; S3: Selecting the four-bar knee joint component data: the dimensions and initial motion positions of the first link 221 , the two second links 222 , the two third links 223 , and the two fourth links 224 , as optimization parameters; S4: Establish an objective function based on the ideal instantaneous center trajectory equation of the human knee joint and perform data optimization. The optimized result is the initial structural size of the artificial knee joint.

[0033] Finally, the comparison results of the instantaneous center trajectory of the variable instantaneous center artificial knee joint during knee flexion and the ideal instantaneous center trajectory of the human body are as follows: Figure 4 As shown, the instantaneous center trajectory of the four-bar variable instantaneous center structure 22 of the knee joint during knee flexion has a good match with the ideal instantaneous center trajectory of the human body.

[0034] Among them, the method of using the above-mentioned pneumatic muscle four-link variable instantaneous center lower limb rehabilitation exoskeleton for impedance training is as follows: first, the control unit reads the preset training program parameters and inflates the initial pressure P0 of the knee joint pneumatic muscle No. 1 211 and the knee joint pneumatic muscle No. 2 212 to a safe pressure of 0.1 MPa. When the user starts joint flexion and extension movement, the control unit collects the angle and angular velocity of the knee joint in real time. If it is detected that the direction of movement of the knee joint is flexion, the control unit increases the pressure P2 of the knee joint No. 2 pneumatic muscle 212 to the target pressure of 0.3 MPa, while maintaining the pressure of the knee joint No. 1 pneumatic muscle 211 at a safe pressure of 0.1 MPa or slightly lower than the target pressure, so as to generate an impedance torque opposite to the flexion direction through the pressure difference on both sides; the specific inflation amount is dynamically adjusted according to linear mapping. When the knee joint angle approaches the maximum flexion angle, P2 falls back to P0 to avoid excessive resistance at the end; if it is detected that the direction of movement of the knee joint is extension, the control unit increases the pressure P1 of the knee joint No. 1 pneumatic muscle 211 to the target pressure of 0.3 MPa, the pressure of the knee joint No. 2 pneumatic muscle 212 is maintained at P0 or slightly lower than the target air pressure. The specific inflation volume is dynamically adjusted according to the linear mapping. When the knee joint angle approaches the initial angle, P1 is gradually reduced to P0. After the training, the pneumatic muscle is steadily exhausted to P0 or the ambient pressure to release the impedance state.

[0035] The above are only embodiments of the present invention. The invention is not limited to the fields involved in this implementation case. Common knowledge such as the known specific structures and characteristics in the scheme is not described in detail here. Ordinary technicians in the relevant field are aware of all common technical knowledge in the technical field to which the invention belongs before the application date or priority date, can obtain all existing technologies in the field, and have the ability to apply conventional experimental means before that date. Ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the inspiration given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several variations and improvements can be made, which should also be regarded as the scope of protection of the present invention. These will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A pneumatic muscle four-link variable instantaneous heart lower limb rehabilitation exoskeleton, comprising a waist fixing part, a hip joint assembly connected to the waist fixing part, a knee joint assembly connected to the hip joint assembly, and a foot assembly connected to the knee joint assembly, characterized in that: The knee joint assembly includes a hip-knee plate, a four-link variable instant center structure constituting the knee joint, and a calf connecting rod. The hip-knee plate and the four-link variable instant center structure are equipped with a thigh pneumatic muscle assembly for driving the knee joint movement. The knee joint four-bar variable instant center structure includes a first link, two second links, two third links, two fourth links, a first driving shaft, a second driving shaft, a first driven shaft, a second driven shaft and a third driven shaft. The third link is arranged in a V shape, the calf connecting rod is connected to the third link, the two second links are parallel, the two third links are parallel, and the two fourth links are parallel. One end of the third link is rotatably connected to one end of the second link through the first driving shaft, the end of the third link away from the first driving shaft is rotatably connected through the second driving shaft, the middle part of the third link and one end of the fourth link are rotatably connected through the first driven shaft, the first link, the ends of the two fourth links away from the first driven shaft and the bottom of the hip-knee board are rotatably connected through the second driven shaft, the bottom of the hip-knee board and the end of the second link close to the hip-knee board and away from the first driving shaft are rotatably connected through the third driven shaft, and the end of the second link away from the hip-knee board and away from the first driving shaft is rotatably connected to the first link; The sole assembly is detachably connected to the calf connecting rod.

2. The pneumatic muscle four-link variable instantaneous heart lower limb rehabilitation exoskeleton according to claim 1, characterized in that: The hip joint assembly includes a hip-leg plate No. 1 and a hip-leg plate No. 2, and hip-leg plate No. 1 and hip-leg plate No. 2 are installed with hip joint pneumatic muscle components for driving hip joint movements, and the lower end of hip-leg plate No. 1 is hinged to the upper end of hip-leg plate No. 2; the plantar assembly includes an ankle-knee connecting plate, an elastic component and a plantar plate, and the ankle-knee connecting plate is connected to the plantar plate through the elastic component; a number of through holes are provided on the hip-knee plate, hip-leg plate No. 2 and calf connecting rod, and a linear groove is provided on the ankle-knee connecting plate, the upper end of the hip-knee plate is detachably connected to the lower end of the hip-leg plate No. 2, and the lower end of the calf connecting rod is detachably connected to the ankle-knee connecting plate.

3. The pneumatic muscle four-link variable instantaneous heart lower limb rehabilitation exoskeleton according to claim 1, characterized in that: The thigh pneumatic muscle assembly includes knee joint pneumatic muscle No. 1 and knee joint pneumatic muscle No.

2. Both ends of knee joint pneumatic muscle No. 1 and knee joint pneumatic muscle No. 2 are provided with fisheye joints. The top ends of knee joint pneumatic muscle No. 1 and knee joint pneumatic muscle No. 2 are hinged to the upper end of the hip knee plate through the fisheye joint, and the bottom ends of knee joint pneumatic muscle No. 1 and knee joint pneumatic muscle No. 2 are hinged to the first drive shaft and the second drive shaft respectively through the fisheye joint.

4. The pneumatic muscle four-link variable instantaneous heart lower limb rehabilitation exoskeleton according to claim 3, characterized in that: The knee joint assembly is provided with a knee joint coupling, a knee joint angle encoder and a limit link. The knee joint angle encoder is arranged at the connection between the first link and the second link. The knee joint angle encoder rotates synchronously with the second link through the knee joint coupling. One end of the limit link is fixedly connected to the hip knee plate, and the other end is fixedly connected to the first link. A limit block is fixedly provided on the first link, and the limit block extends to above the fourth link. A limit sleeve is provided on the fisheye joint connecting the knee joint No. 1 pneumatic muscle and the first drive shaft.

5. The pneumatic muscle four-link variable instantaneous heart lower limb rehabilitation exoskeleton according to claim 2, characterized in that: The knee joint assembly is provided with a hip-knee fixing part and a calf fixing part. Several through holes are provided on the hip-leg plate No. 1, the hip-knee plate and the calf connecting rod. Straight grooves are provided on the waist fixing part, the hip-knee fixing part and the calf fixing part. The hip-leg plate No. 1 is detachably connected to the waist fixing part, the hip-knee plate is detachably connected to the hip-knee fixing part, and the calf connecting rod is detachably connected to the calf fixing part.

6. The pneumatic muscle four-link variable instantaneous heart lower limb rehabilitation exoskeleton according to claim 2, characterized in that: The hip joint pneumatic muscle assembly includes hip joint pneumatic muscle No. 1 and hip joint pneumatic muscle No.

2. Both ends of hip joint pneumatic muscle No. 1 and hip joint pneumatic muscle No. 2 are provided with fisheye joints. The top ends of hip joint pneumatic muscle No. 1 and hip joint pneumatic muscle No. 2 are hinged to the upper end of hip leg plate No. 1 through the fisheye joint, and the bottom ends of hip joint pneumatic muscle No. 1 and hip joint pneumatic muscle No. 2 are hinged to the upper end of hip leg plate No. 2 through the fisheye joint.

7. The pneumatic muscle four-link variable instantaneous heart lower limb rehabilitation exoskeleton according to claim 2, characterized in that: The hip joint assembly is provided with a hip joint coupling and a hip joint angle encoder. The hip joint coupling and the hip joint angle encoder are arranged at the hinge point between the lower end of the hip leg plate No. 1 and the upper end of the hip leg plate No.

2. The hip joint angle encoder rotates synchronously with the hip leg plate No. 2 through the hip joint coupling.

8. The pneumatic muscle four-link variable instantaneous heart lower limb rehabilitation exoskeleton according to claim 2, characterized in that: The hip joint assembly is provided with an adjustment belt, which is detachably connected to the hip-leg plate No. 1; the waist fixing part is provided with two left-right symmetrical C-shaped parts, and the waist fixing part is provided with a waist adjustment plate, and one end of the two C-shaped parts is detachably connected to the waist adjustment plate.

9. The pneumatic muscle four-link variable instantaneous heart lower limb rehabilitation exoskeleton according to claim 2, characterized in that: The elastic component includes a slip ring, a pneumatic telescopic spring, a coil spring, an ankle joint hinge seat, a spring mounting seat and a plantar connecting plate. A linear groove is provided on the plantar connecting plate. The slip ring is slidingly connected to the ankle-knee connecting plate. The ankle-knee connecting plate is hinged to the ankle joint hinge seat. The ankle joint hinge seat is rotatably connected to the spring mounting seat. The spring mounting seat is detachably connected to the plantar connecting plate. The plantar connecting plate is fixedly connected to the plantar plate. The coil spring is coaxially sleeved on the outside of the pneumatic telescopic spring. One end of the pneumatic telescopic spring and the coil spring is hinged to the slip ring. The end of the pneumatic telescopic spring and the coil spring away from the slip ring is hinged to the spring component mounting seat.

10. An impedance training method, characterized in that: The method for performing impedance training with the pneumatic muscle four-link variable instantaneous heart lower limb rehabilitation exoskeleton according to any one of claims 1 to 9 comprises: Read the preset training program parameters and initially inflate both the knee joint No. 1 pneumatic muscle and the knee joint No. 2 pneumatic muscle to the safety pressure P0; The control unit collects the angle and angular velocity of the knee joint in real time. If it detects that the knee joint is moving in the direction of flexion, the control unit increases the pressure of the knee joint's No. 2 pneumatic muscle P2 to the target pressure, while maintaining the pressure of the knee joint's No. 1 pneumatic muscle at a safe pressure P0 or slightly below the target pressure. The specific inflation volume is dynamically adjusted according to a linear mapping. When the knee joint angle approaches the maximum flexion angle, P2 drops back to P0 to avoid excessive resistance at the end. If it is detected that the knee joint is moving in the extension direction, the control unit will increase the pressure of the knee joint No. 1 pneumatic muscle P1 to the target pressure, and maintain the pressure of the knee joint No. 2 pneumatic muscle at P0 or slightly below the target pressure. The specific inflation volume is dynamically adjusted according to the linear mapping, and gradually reduced to P0 when the knee joint angle approaches the initial angle; After training, the controller will exhaust gas steadily to P0 or ambient pressure to release the impedance state.

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