A variable stiffness rope-driven knee rehabilitation system

Abstract

The application discloses a knee joint rehabilitation system driven by a variable stiffness rope, which comprises a liftable handrail type rehabilitation wheelchair, a variable stiffness rope driving system, an exoskeleton waist stepless adjusting mechanism and an exoskeleton leg mechanism; the variable stiffness rope driving system comprises two variable stiffness rope driving modules and is arranged on the back of the wheelchair; the exoskeleton leg mechanism drives the flexion and extension movement of the knee joint and the ankle joint of the exoskeleton in the exoskeleton leg mechanism through the flexion steel wire rope and the extension steel wire rope in the variable stiffness rope driving module. The application satisfies the requirement that the handrail is lowered when the patient is in a sitting position for training, and when the sitting position training is mature, the patient can stand up by relying on the raised handrail with both hands and trying to put the feet on the ground.

Description

Technical Field

[0001] This invention relates to the field of knee joint rehabilitation system technology, and more specifically to a variable stiffness rope-driven knee joint rehabilitation system. Background Technology

[0002] After knee replacement surgery, patients often use passive rehabilitation training devices to train knee flexion and extension movements and lower limb muscle strength in order to restore knee function. However, currently, passive rehabilitation training devices have a relatively simple structure, a relatively simple training mode, and relatively low rehabilitation efficiency.

[0003] The training methods for rehabilitation devices are generally in lying and standing positions. Lying position training has a smaller load and a poorer rehabilitation effect; standing position training has a larger load, but it is more challenging for patients with limited mobility to perform standing position training.

[0004] Dynamic joint rehabilitation training devices hold more promise than passive devices, enabling different training modes at different stages of patient rehabilitation. Traditional high-deceleration-ratio, high-stiffness driven joints have limited application in exoskeletons, failing to meet the need for compliant interaction with the human body. Typical exoskeleton designs directly mount the motor at the joint, increasing the inertia of the exoskeleton's legs and complicating control. While rope-driven systems are used in exoskeletons, current solutions are typically unidirectional, only capable of flexion or extension, and the driving ropes are prone to detachment. On the other hand, some series-connected elastic actuators exist to reduce the stiffness of the driven joint; however, constant-stiffness elastic actuators cannot adjust to the optimal stiffness parameters based on different human movement patterns. Summary of the Invention

[0005] In order to overcome the above technical problems, the purpose of this invention is to provide a variable stiffness rope driven knee joint rehabilitation system that allows patients to lower the handrails during seated training and, when the time is right for seated training, to use their hands to support the raised handrails and try to stand up.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A variable stiffness rope-driven knee joint rehabilitation system includes a height-adjustable armrest rehabilitation wheelchair 1, a variable stiffness rope drive system 2, an exoskeleton lumbar stepless adjustment mechanism 3, and an exoskeleton leg mechanism 4. The variable stiffness rope drive system 2 contains two variable stiffness rope drive modules located at the back of the wheelchair. The exoskeleton leg mechanism 4 is driven by the flexion steel wire rope 208 and extension steel wire rope 211 in the variable stiffness rope drive modules to drive the flexion and extension movements of the knee and ankle joints of the exoskeleton inside the exoskeleton leg mechanism 4.

[0008] The height-adjustable armrest rehabilitation wheelchair 1 includes a lifting motor adapter plate 102, a lead screw optical axis fixing seat 103, a lead screw optical axis limiting block 107, a connecting rod seat one 108, and a connecting rod seat two 110 arranged on both sides of the wheelchair. The lifting motor 101 is connected to the lifting motor adapter plate 102. The lifting lead screw 106 is coaxially connected to the lifting motor 101 and passes through the lead screw optical axis fixing seat 103 and the lead screw optical axis limiting block 107. The sliding optical axis 105 is parallel to the lifting lead screw 106. The arrangement is such that both ends are fixed to the lead screw optical axis fixing seat 103 and the lead screw optical axis limiting block 107 respectively. The nut slider 104 is installed in conjunction with the sliding optical axis 105 and the lifting lead screw 106. The nut slider 104 slides back and forth along the sliding optical axis 105 under the drive of the lifting motor 101. One end of the support connecting rod 109 and the support connecting rod 4 117 are connected to the connecting rod seat 2 110 and the connecting rod seat 108 respectively, and the other end is connected to both ends of the I-shaped connecting rod 118 respectively.

[0009] The adjustable armrest rehabilitation wheelchair 1 is provided with a wheelchair side bar, an I-shaped connecting rod 118, a first support connecting rod 109, and a fourth support connecting rod 117 on its side. The wheelchair side bar, the I-shaped connecting rod 118, the first support connecting rod 109, and the fourth support connecting rod 117 form a parallelogram. One end of the second support connecting rod 112 and the third support connecting rod 116 is connected to both ends of the I-shaped connecting rod 118, and the other end is connected to both ends of the armrest rod 114, armrest hinge block 113 and armrest hinge block 215, respectively. Next, the handrail 114, the I-shaped connecting rod 118, the second support connecting rod 112, and the third support connecting rod 116 form another parallelogram. The second synchronous gear 120 is coaxially and fixedly connected to one end of the hinge hole of the first support connecting rod 109. The first synchronous gear 111 is coaxially and fixedly connected to one end of the hinge hole of the second support connecting rod 112. The second synchronous gear 120 and the first synchronous gear 111 are in transmission cooperation. The nut slider 104 and the fourth support connecting rod 117 are connected by the push connecting rod 119.

[0010] The variable stiffness rope drive system 2 includes a drive wheel 209 and a drive main shaft 221 coaxially fixed on the drive mechanism base plate 201. The drive wheel 209 and the large bevel gear 210 are coaxially fixed. The lower end of the drive main shaft 221 is mounted on the drive mechanism base plate 201 through the base bearing 222. The bearing cover 205 is mounted on the upper end of the drive main shaft 221 through the pressure plate bearing 223. The two ends of the bearing cover 205 are fixed on the drive mechanism base plate 201 through the bending cable guide block 206 and the stretching cable guide block 213, respectively. The drive motor 202 is fixed on the drive mechanism base plate 201 through the drive motor seat 203. The small bevel gear 204 is connected to the output shaft of the drive motor 202 and cooperates with the large bevel gear 210 for transmission. A variable stiffness elastic mechanism is arranged on the left and right sides of the drive motor 202 axial direction.

[0011] The variable stiffness elastic mechanism includes a stiffness adjusting motor 219, which is fixed to the drive mechanism base plate 201 via a stiffness adjusting motor support 234. One end of an adjusting screw 224 is coaxially fixed to the output shaft of the stiffness adjusting motor 219, and the other end of the adjusting screw 224 is mounted on a limiting support 233, which is fixed to the drive mechanism base plate 201. Two adjusting guide rails 220 are parallel to the adjusting screw 224 and distributed on both sides of the adjusting screw 224. The two ends of the two adjusting guide rails 220 are respectively connected to the stiffness adjusting motor support. 234 and the limiting support 233 are fixed together. The nut sliding block 216 is assembled on the adjusting screw 224 and is mounted on the adjusting guide rail 220 through the slider linear bearing 226. On the other side of the nut sliding block 216, there are two parallel spring sliding shafts 225 mounted on the nut sliding block 216 through two slider linear bearings 226. One end of the spring sliding shaft 225 is connected to the pulley fixing block 215 and the guide pulley 214 respectively. The other end of the spring sliding shaft 225 passes through the adjusting spring 217 and is connected to the optical axis fixing block 218.

[0012] The drive wheel 209 has a bending wire rope fixing hole 229 and a stretching wire rope fixing hole 230 on its surface. The drive wheel 209 also has a bending wire rope groove 232 and a stretching wire rope groove 231 on its side. A bending wire rope fixing block 227 is fixed in the bending wire rope fixing hole 229. The bending wire rope 208 is sequentially wound around the bending wire rope groove 232 and the guide pulley 214 on the drive wheel 209, and passes through the bending guide block 227. 06, and is fitted in the bending cable tube 207, the extension wire rope fixing block 228 is fixed in the extension wire rope fixing hole 230, the extension wire rope 211 is wound in the extension wire rope groove 231 of the drive wheel 209 and another guide pulley 214, passes through the extension cable guide block 213, and is fitted in the extension cable tube 212, the bending wire rope 208 and the extension wire rope 211 are powered by the drive motor 202.

[0013] The exoskeleton lumbar stepless adjustment mechanism 3 includes a lumbar fixation groove 301 installed at the bottom of the wheelchair 100, width structural plates 310 arranged on the left and right sides of the lumbar fixation groove 301, the width structural plates 310 sliding freely in the lumbar fixation groove 301, a width adjustment motor 302 fixed in the middle of the lumbar fixation groove 301 by an adjustment motor seat 303, a lead screw support 304 fixed at each of the left and right ends of the lumbar fixation groove 301, an adjustment lead screw 307 installed between the adjustment motor seat 303 and the lead screw support 304, two adjustment sliders 305 fixed together with the width structural plates 310 on the left and right sides respectively, an adjustment nut 306 installed on the adjustment slider 305 and installed together with the adjustment lead screw 307, two adjustment bevel gears 308 connected to the end of the adjustment lead screw 307 near the adjustment motor seat 303 respectively, a motor bevel gear 309 connected to the output shaft of the width adjustment motor 302, the motor bevel gear 309 and the two adjustment bevel gears 308 arranged vertically and engaged.

[0014] The exoskeleton leg mechanism 4 includes a thigh adapter plate 401 fixedly connected to the width structural plate 310. The thigh adapter plate 401 is connected to a knee joint support member 407, which serves as a rotational support for the knee joint. The knee joint support member 407 is connected to a lower leg adapter plate 403 via a joint bearing 410. The knee joint support member 407 is connected to a knee joint cover plate 402, which axially restricts the movement of the lower leg adapter plate 403. The knee joint cover plate 402 is provided with an extension lasso hole 411 and a flexion lasso hole 412. An extension hole 408 and a bending hole 409 are provided on the lower leg adapter plate 403. The extension wire rope 211 passes through the extension loop hole 411 and its end is fixed in the extension hole 408. The bending wire rope 208 passes through the bending loop hole 412 and its end is fixed in the bending hole 409. The extension loop tube 212 and the bending loop tube 207 are respectively sleeved on the extension wire rope 211 and the bending wire rope 208. The extension loop tube 212 and the bending loop tube 207 are respectively assembled in the extension loop hole 411 and the bending loop hole 412.

[0015] The lower leg adapter plate 403 is fixed to the lower leg base plate 404, the lower leg sliding plate 405 and the ankle joint adapter 406 are connected together, the sliding cover plate 420 is installed on the lower leg base plate 404, the spring pin 421 is installed on the sliding cover plate 420, a row of pin holes 422 are provided on the lower leg sliding plate 405, the lower leg sliding plate 405 slides in the sliding groove of the lower leg base plate 404, and any one of the pin holes 422 is selected to cooperate with the pin head of the spring pin 421;

[0016] Ankle joint adapter 406 and ankle joint hinge block 413 are hinged together to achieve the inward / outward swing freedom of the ankle joint. Ankle joint hinge block 413 and foot body 414 are hinged together to achieve the flexion and extension freedom of the ankle joint. Foot body 414 is fixedly connected to heel ring 415 to form a complete exoskeleton foot. An extension loop opening 417 and a flexion loop opening 416 are respectively located on the front and rear sides of ankle joint hinge block 413. There are extension anchor points 419 and bending anchor points 418 on the front and rear sides respectively. The extension wire rope 211 passes through the extension sleeve opening 417 and its end is fixed at the extension anchor point 419. The bending wire rope 208 passes through the bending sleeve opening 416 and its end is fixed at the bending anchor point 418. The extension sleeve tube 212 and the bending sleeve tube 207 are respectively fitted onto the extension wire rope 211 and the bending wire rope 208, and the extension sleeve tube 212 and the bending sleeve tube 207 are respectively assembled at the extension sleeve opening 417 and the bending sleeve opening 416.

[0017] The beneficial effects of this invention are:

[0018] This invention allows patients to easily switch the height of the handrails when sitting or standing, effectively supporting and protecting them.

[0019] This invention employs a variable stiffness rope drive system with the power mechanism positioned at the rear. A single drive motor in this system can simultaneously drive two directions of movement of the target joint. A variable stiffness elastic mechanism is added to the traditional link, which on the one hand prevents the rope from detaching from the drive wheel; on the other hand, it allows for real-time adjustment of stiffness parameters, enhancing assist efficiency and human comfort.

[0020] In terms of energy loss, due to the introduction of an elastomer, there is a process of spring compression and release during the flexion and extension of the knee or ankle joints. Therefore, overload energy can be stored in the spring and released when the spring returns to its initial state, which can reduce the peak power of the power drive, making the force output smoother and greatly improving the assist efficiency. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a variable stiffness rope-driven knee rehabilitation system.

[0022] Figure 2 This is a schematic diagram of a rehabilitation wheelchair with adjustable armrests.

[0023] Figure 3 This is a schematic diagram of a height-adjustable handrail.

[0024] Figure 4 This is a schematic diagram of a rope-driven variable stiffness rehabilitation exoskeleton mechanism.

[0025] Figure 5 This is a schematic diagram of a variable stiffness rope drive system.

[0026] Figure 6 This is a schematic diagram of the bottom structure of a variable stiffness rope drive system.

[0027] Figure 7 This is a schematic diagram of the core mechanism of the variable stiffness rope drive system.

[0028] Figure 8 This is a schematic diagram of a rope-driven winding wheel.

[0029] Figure 9 This is a schematic diagram of a variable stiffness elastic mechanism.

[0030] Figure 10 This is a schematic diagram of the drive rope winding method.

[0031] Figure 11 This is a schematic diagram of the stepless adjustment mechanism for the waist section of the exoskeleton.

[0032] Figure 12 This is a schematic diagram of the exoskeleton leg structure.

[0033] Figure 13 This is a schematic diagram of an exoskeleton knee joint mechanism.

[0034] Figure 14 This is a schematic diagram of the exoskeleton ankle joint mechanism.

[0035] Figure 15 This is a schematic diagram of the leg mechanism.

[0036] The invention comprises: 1-a height-adjustable armrest rehabilitation wheelchair, 2-a variable stiffness rope drive system, 3-a stepless adjustment mechanism for the waist of the exoskeleton, 4-a leg mechanism of the exoskeleton, and 5-a hardware control box for the rehabilitation system.

[0037] 1. A height-adjustable armrest rehabilitation wheelchair, comprising: 100 wheelchair (this wheelchair can be a common general-purpose wheelchair on the market), 101 lifting motor, 102 lifting motor adapter plate, 103 lead screw optical axis fixing seat, 104 nut slider, 105 sliding optical axis, 106 lifting lead screw, 107 lead screw optical axis limiting block, 108 connecting rod seat one, 110 connecting rod seat two, 109 support connecting rod one, 112 support connecting rod two, 116 support connecting rod three, 117 support connecting rod four, 111 synchronous gear one, 113 armrest hinge block one, 115 armrest hinge block two, 114 armrest trunk, 118 I-shaped connecting rod, 119 propulsion connecting rod, and 120 synchronous gear two.

[0038] 2. Variable stiffness rope drive system, including: 201 drive mechanism base plate, 202 drive motor, 203 drive motor mount, 204 small bevel gear, 205 bearing cap, 206 bending cable guide block, 207 bending cable tube, 208 bending wire rope, 209 drive wheel, 210 large bevel gear, 211 extension wire rope, 212 extension cable tube, 213 extension cable guide block, 214 guide pulley, 215 pulley fixing block, 216 nut sliding block, 217 adjusting spring, 21... 8. Optical axis fixing block; 219. Stiffness adjustment motor; 220. Adjustment guide rail; 221. Drive spindle; 222. Base bearing; 223. Pressure plate bearing; 224. Adjustment screw; 225. Spring sliding shaft; 226. Slider linear bearing; 227. Bending steel wire rope fixing block; 228. Extending steel wire rope fixing block; 229. Bending steel wire rope fixing hole; 230. Extending steel wire rope fixing hole; 231. Extending steel wire rope groove; 232. Bending steel wire rope groove; 233. Limit support; 234. Stiffness adjustment motor support.

[0039] 3. The stepless adjustment mechanism for the waist of the exoskeleton includes: 301 waist fixing groove, 302 width adjustment motor, 303 adjustment motor base, 304 lead screw support, 305 adjustment slider, 306 adjustment nut, 307 adjustment lead screw, 308 adjustment bevel gear, 309 motor bevel gear, and 310 width structural plate.

[0040] 4. Exoskeleton leg mechanism, including: 401 thigh adapter plate, 402 knee joint cover plate, 403 lower leg adapter plate, 404 lower leg base plate, 405 lower leg sliding plate, 406 ankle joint adapter, 407 knee joint support, 408 extension action hole, 409 flexion action hole, 410 joint bearing, 411 extension lasso hole, 412 flexion lasso hole, 413 ankle joint hinge block, 414 foot body, 415 heel ring, 416 flexion lasso opening, 417 extension lasso opening, 418 flexion anchor point, 419 extension anchor point, 420 sliding cover plate, 421 spring pin, 422 pin hole. Detailed Implementation

[0041] The present invention will now be described in further detail with reference to the accompanying drawings.

[0042] Overall structure as Figure 1 As shown, a 100-wheelchair (which can be a common, universal wheelchair on the market) serves as the platform for the entire system.

[0043] exist Figure 3In the description of the height-adjustable armrest, the lifting motor adapter plate 102, the lead screw shaft fixing seat 103, the lead screw shaft limiting block 107, and the connecting rod seats 108 and 110 are all fixed to the left (or right) side of the wheelchair. The lifting motor 101 is connected to the lifting motor adapter plate 102. The lifting lead screw 106 is coaxially connected to the lifting motor 101 and passes through the lead screw shaft fixing seat 103 and the lead screw shaft limiting block 107. The sliding shaft 105 is arranged parallel to the lifting lead screw 106, and its two ends are fixed to the lead screw shaft fixing seat 103 and the lead screw shaft limiting block 107, respectively. The nut slider 104 is installed in conjunction with both the sliding shaft 105 and the lifting lead screw 106, and the nut slider 104 can slide back and forth along the sliding shaft 105 under the drive of the lifting motor 101. One end of the support connecting rods 109 and 117 is connected to the connecting rod seats 110 and 108 respectively, and the other end is connected to both ends of the I-shaped connecting rod 118 respectively.

[0044] The wheelchair side bar, I-beam connecting rod 118, and support connecting rods 109 and 117 form a parallelogram. One end of support connecting rods 112 and 116 is connected to both ends of the I-beam connecting rod 118, and the other end is connected to the two ends of the armrest hinge blocks 113 and 115 of the armrest rod 114. The armrest rod 114, I-beam connecting rod 118, and support connecting rods 112 and 116 form another parallelogram. Synchronizing gear 120 is coaxially fixedly connected to one end of the hinge hole of support connecting rod 109, and synchronous gear 111 is coaxially fixedly connected to one end of the hinge hole of support connecting rod 112, with synchronous gear 111 and synchronous gear 120 engaging in a transmission relationship. The nut slider 104 and support connecting rod 117 are connected via a pusher connecting rod 119. When the nut slider 104 slides, the angles of the first support rod 109 and 117 change synchronously; under the action of the first synchronous gear 111 and the second synchronous gear 120, the angles of the second support rod 112 and 116 change synchronously, thus the handrail 114 achieves a lifting and lowering motion, allowing the handrails to rise when the user stands up, providing real-time body support. The handrail's lowering and raising states are as follows: Figure 2 As shown.

[0045] The variable stiffness rope drive system 2 contains two variable stiffness rope drive modules located at the back of the wheelchair. For example... Figure 5 , Figure 6 As shown, in a variable stiffness rope drive module, the variable stiffness rope drive system contains two drive units, each of which can drive the flexion and extension movements of a joint. Here, we take a single drive unit (left side) as an example for a detailed introduction.

[0046] In the variable stiffness rope drive system, all drive mechanisms are mounted on the drive mechanism base plate 201. The drive wheel 209 and drive spindle 221 are coaxially fixed, and the large bevel gear 210 is coaxially fixed with the drive wheel 209. The lower end of the drive spindle 221 is mounted on the drive mechanism base plate 201 via a base bearing 222. The bearing cap 205 is mounted on the upper end of the drive spindle 221 via a pressure plate bearing 223, and both ends of the bearing cap 205 are fixed to the drive mechanism base plate 201 via a bending cable guide block 206 and a stretching cable guide block 213, respectively. The drive motor 202 is fixed to the drive mechanism base plate 201 via a drive motor mount 203. The small bevel gear 204 is connected to the output shaft of the drive motor 202 and engages with the large bevel gear 210 for transmission. On the left and right sides of the drive motor 202 along its axial direction, a variable stiffness elastic mechanism is arranged, such as... Figure 7 As shown. The stiffness adjustment motor 219 is fixed to the drive mechanism base plate 201 via the stiffness adjustment motor support 234. One end of the adjusting screw 224 is coaxially fixed with the output shaft of the stiffness adjustment motor 219, and the other end of the adjusting screw 224 is mounted on the limiting support 233, which is fixed to the drive mechanism base plate 201. Two adjusting guide rails 220 are parallel to the adjusting screw 224 and are distributed on both sides of the adjusting screw 224. The two ends of the two adjusting guide rails 220 are fixed to the stiffness adjustment motor support 234 and the limiting support 233, respectively. The nut sliding block 216 is assembled on the adjusting screw 224 and is mounted on the adjusting guide rail 220 via the slider linear bearing 226. On the other side of the nut sliding block 216, there are two parallel spring sliding shafts 225 mounted on the nut sliding block 216 via two slider linear bearings 226. One end of the spring sliding shaft 225 is connected to the pulley fixing block 215 and the guide pulley 214 respectively; the other end of the spring sliding shaft 225 passes through the adjusting spring 217 and is connected to the optical shaft fixing block 218. When the pulley fixing block 215 is pulled, the spring sliding shaft 225 can slide in the nut sliding block 216, and the adjusting spring 217 will be compressed. By controlling the movement of the stiffness adjusting motor 219, the position of the nut sliding block 216 (i.e., the starting point of the compression of the adjusting spring 217) can be adjusted, thereby changing the degree of compression of the adjusting spring 217.

[0047] In a rope-driven system, a single drive joint contains two power output ropes, such as... Figure 10 As shown. Figure 8 As shown, the drive wheel 209 includes two rope fixing holes: a bending wire rope fixing hole 229 and a stretching wire rope fixing hole 230, which correspond to the bending wire rope groove 232 and the stretching wire rope groove 231, respectively.

[0048] The bending wire rope fixing block 227 on the bending wire rope 208 is located in the bending wire rope fixing hole 229 on the drive wheel 209. The bending wire rope 208 is sequentially wound in the bending wire rope groove 232 and the guide pulley 214 on the drive wheel 209, passes through the bending cable guide block 206, and is fitted in the bending cable tube 207, serving as the joint flexion power output. The extension wire rope fixing block 228 on the extension wire rope 211 is fixed in the extension wire rope fixing hole 230 on the drive wheel 209. The extension wire rope 211 is sequentially wound in the extension wire rope groove 231 and another guide pulley 214 on the drive wheel 209, passes through the extension cable guide block 213, and is fitted in the extension cable tube 212, serving as the joint extension power output.

[0049] By controlling the forward and reverse rotation of the drive motor 202, the motion output of the bending wire rope 208 and the extending wire rope 211 can be controlled. Throughout the transmission chain, the presence of the adjusting spring 217 reduces the system's rigidity. By controlling the stiffness adjusting motor 219, on the one hand, the tension of the ropes can be adjusted to prevent the bending wire rope 208 and the extending wire rope 211 from falling out of the bending wire rope groove 232 and the extending wire rope groove 231; on the other hand, the output stiffness of the bending wire rope 208 and the extending wire rope 211 can be adjusted. The drive stiffness can be adjusted in real time according to different motion scenarios and motion phases, enhancing the compliance of the exoskeleton drive and the wearer's comfort.

[0050] The exoskeleton's stepless waist adjustment mechanism 3 is fixed to the bottom of the waist fixation groove 301 and the wheelchair 100. Width structure plates 310 are installed on the left and right sides of the waist fixation groove 301 and can slide freely within it. A width adjustment motor 302 is fixed to the middle of the waist fixation groove 301 via an adjustment motor base 303. A lead screw support 304 is fixed to each of the left and right ends of the waist fixation groove 301. Two adjustment lead screws 307 are installed between the adjustment motor base 303 and the lead screw supports 304. Two adjustment sliders 305 are fixed to the width structure plates 310 on the left and right sides respectively. Adjustment nuts 306 are installed on the adjustment sliders 305 and cooperate with the adjustment lead screws 307. Two adjustment bevel gears 308 are connected to the ends of the adjustment lead screws 307 near the adjustment motor base 303. A motor bevel gear 309 is connected to the output shaft of the width adjustment motor 302. Overall, the motor bevel gear 309 and the two adjusting bevel gears 308 are arranged vertically and cooperate with each other. When the width adjusting motor 302 drives the motor bevel gear 309 to rotate, the two adjusting bevel gears 308 rotate in the clockwise and counterclockwise directions respectively. That is, the two adjusting nuts 306 drive the width structure plates 310 on both sides to slide inward or outward at the same time, so as to realize the function of width adjustment between the two legs of the exoskeleton.

[0051] Exoskeleton Leg Mechanism 4 Overall Design (Single Leg) as follows Figure 12 As shown. The flexion and extension movements of the exoskeleton's knee and ankle joints are driven by two variable stiffness rope drive systems: a flexion wire rope 208 and a extension wire rope 211. Figure 4 As shown.

[0052] The knee joint structure of an exoskeleton, such as Figure 13 As shown, the thigh adapter plate 401 is fixedly connected to the width structural plate 310. The knee joint support 407 serves as a rotational support for the knee joint and is connected to the thigh adapter plate 401. The lower leg adapter plate 403 is mounted to the knee joint support 407 via a joint bearing 410. The knee joint cover plate 402 is connected to the knee joint support 407 and axially restricts the movement of the lower leg adapter plate 403. The knee joint cover plate 402 has an extension lasso hole 411 and a flexion lasso hole 412, while the lower leg adapter plate 403 has an extension action hole 408 and a flexion action hole 409. The extension wire rope 211 passes through the extension lasso hole 411 and its end is fixed in the extension action hole 408; the flexion wire rope 208 passes through the flexion lasso hole 412 and its end is fixed in the flexion action hole 409. Furthermore, the extension sleeve 212 and the bending sleeve 207 are respectively fitted onto the extension wire rope 211 and the bending wire rope 208. Additionally, the extension sleeve 212 and the bending sleeve 207 are respectively assembled into the extension sleeve hole 411 and the bending sleeve hole 412.

[0053] ankle joint of exoskeleton, such as Figure 14 As shown. The ankle joint adapter 406 and the ankle joint hinge block 413 are hinged together, realizing the inward / outward swing freedom of the foot's ankle joint. The ankle joint hinge block 413 and the foot body 414 are hinged together, realizing the flexion and extension freedom of the ankle joint. The heel ring 415 and the foot body 414 are fixed together to form a complete exoskeleton foot. There are extension loop openings 417 and flexion loop openings 416 on the front and rear sides of the ankle joint hinge block 413, respectively, and there are extension anchor points 419 and flexion anchor points 418 on the front and rear sides of the foot body 414, respectively. The extension wire rope 211 passes through the extension loop opening 417 and its end is fixed to the extension anchor point 419; the flexion wire rope 208 passes through the flexion loop opening 416 and its end is fixed to the flexion anchor point 418. The extension loop tube 212 and the flexion loop tube 207 are respectively fitted onto the extension wire rope 211 and the flexion wire rope 208. Furthermore, the extension tube 212 and the bending tube 207 are respectively assembled at the extension tube opening 417 and the bending tube opening 416.

[0054] The legs of the exoskeleton are retractable, such as... Figure 15As shown. The calf base plate 404 and the calf adapter plate 403 are fixed together, and the calf sliding plate 405 and the ankle joint adapter 406 are connected together. The sliding cover plate 420 is installed on the calf base plate 404, and the spring pin 421 is installed on the sliding cover plate 420. There is an array of pin holes 422 on the calf sliding plate 405. The calf sliding plate 405 can slide in the groove of the calf base plate 404, and can select any pin hole 422 to engage with the pin head of the spring pin 421. Each time the length of the calf is adjusted, pulling the spring pin 421 will disengage the pin head from the pin hole 422, sliding the calf sliding plate 405 to select the extension length, releasing the spring pin 421, and inserting it into the target pin hole 422 to fix the length.

[0055] This invention designs a compact and sophisticated knee joint rehabilitation system:

[0056] This invention employs a variable stiffness rope drive system with the power mechanism positioned at the rear. A single drive motor in this system can simultaneously drive two directions of movement of the target joint. A variable stiffness elastic mechanism is added to the traditional link, which prevents the rope from detaching from the drive wheel and allows for real-time adjustment of stiffness parameters, enhancing assist efficiency and user comfort. Regarding energy loss, the introduction of the elastic body means that during knee or ankle flexion and extension movements, the spring is compressed and released. This allows overload energy to be stored in the spring and released when the spring returns to its initial state, reducing the peak power of the drive and resulting in a smoother force output, significantly improving assist efficiency.

[0057] Regarding the joints, a rear-mounted cable drive system is employed. Within a compact space, a single drive wheel can simultaneously output lasso tension in two directions. A variable-stiffness elastomer is connected in series along the cable drive path, allowing for real-time adjustment of the elastomer's preload. This enables stiffness parameter adjustment for precise output of interaction forces with the external environment, while also ensuring the lasso remains taut during the drive process, preventing it from detaching from the drive wheel. This combination of rigidity and flexibility allows for a higher degree of replication of human joint motion; the output power can be precisely controlled and interacts flexibly with the human body; and the stiffness parameters of the knee and ankle joints can be adjusted, enabling the development of detailed control strategies for different training stages.

[0058] The waist mechanism has an automatically adjustable width; the leg mechanism has an adjustable length.

[0059] The overall technical solution employs a combination of rigidity and flexibility. The knee and ankle joints utilize a cable-driven + variable stiffness series elastic drive design, while the dimensions of the waist and leg mechanisms are adjustable. The exoskeleton's waist and leg sections are designed with adjustable dimensional parameters. Electronic modules, including the main control unit, electronic actuators, and switches, are integrated into the wheelchair's backrest. The wheelchair's lifting armrest mechanism utilizes a crank-slider and double parallelogram mechanism principle to maintain the armrests horizontally during lifting.

[0060] The flexion and extension movements of the knee and ankle joints are driven by ropes. The rope-driven power module is located in the back of the wheelchair, and the rope drive end is directly led to the knee and ankle joint skeleton in the exoskeleton via a lasso transmission. Each drive unit can perform bidirectional flexion and extension movements of one joint. The motor is transversely mounted and transmits motion to the drive wheel through a bevel gear set, reducing the size of the drive mechanism. A linear spring assembly is added to a pulley through which the wire rope passes. When the drive system's rope interacts with external forces, the deformation of the spring assembly represents the magnitude and direction of the human-machine interaction force. This solution, which introduces an elastic body into the link, can significantly reduce the stiffness of the drive mechanism, thereby enhancing human comfort. At the same time, the initial position of the spring assembly can be adjusted by a linear motor, thus adjusting the preload of the wire rope and the output stiffness of the power system. On the one hand, this prevents the rope from slipping off the drive wheel, enhancing the stability of the system's drive. On the other hand, it allows for real-time adjustment of stiffness parameters, enhancing assist efficiency and human comfort.

Claims

1. A variable stiffness rope-driven knee joint rehabilitation system, characterized in that, It includes a height-adjustable armrest rehabilitation wheelchair (1), a variable stiffness rope drive system (2), an exoskeleton waist stepless adjustment mechanism (3), and an exoskeleton leg mechanism (4); the variable stiffness rope drive system (2) is located at the back of the wheelchair, and the exoskeleton leg mechanism (4) drives the flexion and extension movements of the knee and ankle joints of the exoskeleton inside the exoskeleton leg mechanism (4) through the flexion steel wire rope (208) and extension steel wire rope (211) in the variable stiffness rope drive system (2); The variable stiffness rope drive system (2) includes a drive wheel (209) and a drive spindle (221) coaxially fixed on a drive mechanism base plate (201). The drive wheel (209) and the large bevel gear (210) are coaxially fixed. The lower end of the drive spindle (221) is mounted on the drive mechanism base plate (201) via a base bearing (222). The bearing cap (205) is mounted on the upper end of the drive spindle (221) via a pressure plate bearing (223). The two ends of the drive mechanism base plate (201) are fixed by the bending cable guide block (206) and the stretching cable guide block (213) respectively. The drive motor (202) is fixed on the drive mechanism base plate (201) by the drive motor seat (203). The small bevel gear (204) is connected to the output shaft of the drive motor (202) and cooperates with the large bevel gear (210) for transmission. On the left and right sides of the drive motor (202) axis, a variable stiffness elastic mechanism is arranged respectively. The variable stiffness elastic mechanism includes a stiffness adjusting motor (219), which is fixed to the drive mechanism base plate (201) via a stiffness adjusting motor support (234). One end of the adjusting screw (224) is coaxially fixed to the output shaft of the stiffness adjusting motor (219), and the other end of the adjusting screw (224) is mounted on a limiting support (233), which is fixed to the drive mechanism base plate (201). Two adjusting guide rails (220) are parallel to the adjusting screw (224) and distributed on both sides of the adjusting screw (224). The two ends of the two adjusting guide rails (220) are respectively connected to the stiffness adjusting motor support. (234) and the limiting support (233) are fixed together. The nut sliding block (216) is assembled on the adjusting screw (224) and is installed on the adjusting guide rail (220) through the slider linear bearing (226). On the other side of the nut sliding block (216), there are two parallel spring sliding shafts (225) installed on the nut sliding block (216) through the two slider linear bearings (226). One end of the spring sliding shaft (225) is connected to the pulley fixing block (215) and the guide pulley (214) respectively. The other end of the spring sliding shaft (225) passes through the adjusting spring (217) and is connected to the optical axis fixing block (218). The drive wheel (209) has a bent wire rope fixing hole (229) and a stretched wire rope fixing hole (230) on its surface. The drive wheel (209) has a bent wire rope groove (232) and a stretched wire rope groove (231) on its side. The bent wire rope fixing hole (229) is used to fix the bent wire rope (208) on its bent wire rope (208) to a bent wire rope fixing block (227). The bent wire rope (208) is wound in the bent wire rope groove (232) and the guide pulley (214) on the drive wheel (209) in sequence, and passes through the bent wire rope guide block (227). 06), and is fitted in the bending cable tube (207), the extension wire rope fixing block (228) on the extension wire rope (211) is fixed in the extension wire rope fixing hole (230), the extension wire rope (211) is wound in the extension wire rope groove (231) of the drive wheel (209) and another guide pulley (214), passes through the extension cable guide block (213), and is fitted in the extension cable tube (212), the bending wire rope (208) and the extension wire rope (211) are powered by the drive motor (202).

2. The variable stiffness rope-driven knee joint rehabilitation system according to claim 1, characterized in that, The height-adjustable armrest rehabilitation wheelchair (1) includes a lifting motor adapter plate (102), a lead screw optical axis fixing seat (103), a lead screw optical axis limiting block (107), a connecting rod seat one (108), and a connecting rod seat two (110) arranged on both sides of the wheelchair. The lifting motor (101) is connected to the lifting motor adapter plate (102). The lifting lead screw (106) is coaxially connected to the lifting motor (101) and passes through the lead screw optical axis fixing seat (103) and the lead screw optical axis limiting block (107). The sliding optical axis (105) is parallel to the lifting lead screw (106). The two ends are fixed to the lead screw optical axis fixing seat (103) and the lead screw optical axis limiting block (107) respectively. The nut slider (104) is installed in conjunction with the sliding optical axis (105) and the lifting lead screw (106). The nut slider (104) slides back and forth along the sliding optical axis (105) under the drive of the lifting motor (101). One end of the support connecting rod one (109) and the support connecting rod four (117) are connected to the connecting rod seat two (110) and the connecting rod seat one (108) respectively, and the other end is connected to both ends of the I-shaped connecting rod (118).

3. The variable stiffness rope-driven knee joint rehabilitation system according to claim 1, characterized in that, The adjustable armrest rehabilitation wheelchair (1) is provided with a wheelchair side rod, an I-shaped connecting rod (118), a support connecting rod one (109), and a support connecting rod four (117) on its side. The wheelchair side rod, the I-shaped connecting rod (118), the support connecting rod one (109), and the support connecting rod four (117) form a parallelogram. One end of the support connecting rod two (112) and the support connecting rod three (116) are respectively connected to the two ends of the I-shaped connecting rod (118), and the other end is respectively connected to the two ends of the armrest rod (114) armrest hinge block one (113) and armrest hinge block two (115). Next, the handrail (114), the I-shaped connecting rod (118), the second supporting connecting rod (112), and the third supporting connecting rod (116) form another parallelogram. The second synchronous gear (120) is coaxially and fixedly connected to the hinge hole at one end of the first supporting connecting rod (109). The first synchronous gear (111) is coaxially and fixedly connected to the hinge hole at one end of the second supporting connecting rod (112). The second synchronous gear (120) and the first synchronous gear (111) are in transmission cooperation. The nut slider (104) and the fourth supporting connecting rod (117) are connected by the push connecting rod (119).

4. The variable stiffness rope-driven knee joint rehabilitation system according to claim 1, characterized in that, The exoskeleton lumbar stepless adjustment mechanism (3) includes a lumbar fixation groove (301) installed at the bottom of the wheelchair (100), width structural plates (310) located on the left and right sides of the lumbar fixation groove (301), the width structural plates (310) sliding freely in the lumbar fixation groove (301), a width adjustment motor (302) fixed in the middle of the lumbar fixation groove (301) by an adjustment motor seat (303), and a screw rod support (304) fixed at each of the left and right ends of the lumbar fixation groove (301). A screw rod support (304) is installed between the adjustment motor seat (303) and the screw rod support (304). Install the second adjusting screw (307), fix the two adjusting sliders (305) together with the width structure plates (310) on the left and right sides respectively, install the adjusting nut (306) on the adjusting slider (305) and install it together with the second adjusting screw (307), connect the two adjusting bevel gears (308) to the end of the second adjusting screw (307) near the adjusting motor seat (303) respectively, and connect the motor bevel gear (309) to the output shaft of the width adjusting motor (302). The motor bevel gear (309) and the two adjusting bevel gears (308) are arranged vertically and cooperate with each other.

5. The variable stiffness rope-driven knee joint rehabilitation system according to claim 1, characterized in that, The exoskeleton leg mechanism (4) includes a thigh adapter plate (401) fixedly connected to a width structural plate (310). The thigh adapter plate (401) is connected to a knee joint support (407), which serves as a rotational support for the knee joint. The knee joint support (407) is connected to a lower leg adapter plate (403) via a joint bearing (410). The knee joint support (407) is connected to a knee joint cover plate (402) for axially restricting the movement of the lower leg adapter plate (403). The knee joint cover plate (402) is provided with an extension lasso hole (411) and a flexion lasso hole (412). The leg adapter plate (403) is provided with an extension hole (408) and a bending hole (409). The extension wire rope (211) passes through the extension loop hole (411) and its end is fixed in the extension hole (408); the bending wire rope (208) passes through the bending loop hole (412) and its end is fixed in the bending hole (409). The extension loop tube (212) and the bending loop tube (207) are respectively sleeved on the extension wire rope (211) and the bending wire rope (208), and the extension loop tube (212) and the bending loop tube (207) are respectively assembled in the extension loop hole (411) and the bending loop hole (412). The lower leg adapter plate (403) is fixed to the lower leg base plate (404), the lower leg sliding plate (405) and the ankle joint adapter (406) are connected together, the sliding cover plate (420) is installed on the lower leg base plate (404), the spring pin (421) is installed on the sliding cover plate (420), a row of pin holes (422) is provided on the lower leg sliding plate (405), the lower leg sliding plate (405) slides in the groove of the lower leg base plate (404), and any one of the pin holes (422) is selected to cooperate with the pin head of the spring pin (421); Ankle joint adapter (406) and ankle joint hinge block (413) are hinged together to realize the degree of freedom of inward / outward movement of the ankle joint. Ankle joint hinge block (413) and foot body (414) are hinged together to realize the degree of freedom of flexion and extension movement of the ankle joint. Foot body (414) is fixedly connected to heel ring (415) to form a complete exoskeleton foot. There are extension loop openings (417) and flexion loop openings (416) on the front and back sides of the ankle joint hinge block (413), respectively. There are extension loop openings (417) and flexion loop openings (416) on the front and back sides of the foot body (414), respectively. There are extension anchor points (419) and bending anchor points (418). The extension wire rope (211) passes through the extension sleeve opening (417) and its end is fixed at the extension anchor point (419). The bending wire rope (208) passes through the bending sleeve opening (416) and its end is fixed at the bending anchor point (418). The extension sleeve tube (212) and the bending sleeve tube (207) are respectively fitted on the extension wire rope (211) and the bending wire rope (208), and the extension sleeve tube (212) and the bending sleeve tube (207) are respectively assembled at the extension sleeve opening (417) and the bending sleeve opening (416).

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