CN117297932A

CN117297932A - Flexible knee joint exoskeleton rehabilitation robot

Info

Publication number: CN117297932A
Application number: CN202311130154.8A
Authority: CN
Inventors: 孟伟; 朱昶; 刘泉; 董云飞; 艾青松
Original assignee: Wuhan University of Technology WUT
Current assignee: Wuhan University of Technology WUT
Priority date: 2023-09-04
Filing date: 2023-09-04
Publication date: 2023-12-29

Abstract

The invention relates to the technical field of surgery, in particular to a flexible knee joint exoskeleton rehabilitation robot. Including thigh module, shank module, knee joint module and flexible drive module, rotate through knee joint module between thigh module and the shank module and be connected, flexible drive module's drive end is connected with the shank module, flexible drive module includes the motor, the reduction gear, the lead screw, the spring fixing base, push rod drive assembly, lead screw nut expansion board and displacement sensor, lead screw one end is connected to the motor output through the reduction gear, the lead screw other end and lead screw nut expansion board threaded connection, lead screw nut expansion board elasticity sets up in the spring fixing base, spring fixing base bottom and push rod drive assembly one end link firmly, displacement sensor sets firmly on the spring fixing base, and displacement sensor's gleitbretter and lead screw nut expansion board fixed connection. Can realize flexible drive, and drive stability is good, and driving force control accuracy is high.

Description

Flexible knee joint exoskeleton rehabilitation robot

Technical Field

The invention relates to the technical field of surgery, in particular to a flexible knee joint exoskeleton rehabilitation robot.

Background

With the continuous acceleration of the aging trend of the population in China, more and more patients with limb movement dysfunction caused by cerebral apoplexy and other diseases, wherein the patients with knee joint movement dysfunction are most common. Related researches show that the exercise rehabilitation therapy can promote the recovery of the nervous system function of the patient and promote the muscle activity of the patient to a certain extent, and plays a vital role in recovering the exercise capacity of the patient. The traditional manual rehabilitation treatment has the problems of lack of manpower resources of doctors, higher rehabilitation cost and the like, and quantitative evaluation cannot be provided for the rehabilitation effect of patients. The rehabilitation robot can improve the rehabilitation efficiency while guaranteeing the rehabilitation effect, so that the patient can recover the health more quickly; the application of the sensing technology in the rehabilitation robot can quantitatively evaluate the rehabilitation training effect of the patient in real time. In lower limb rehabilitation training, knee joint training is particularly important. The knee joint not only bears most of the weight of the human body, but also provides the greatest force for walking. Therefore, the design of the knee joint exoskeleton rehabilitation robot can meet the basic mode of daily movement of the knee joint of a human body, including flexion and extension movement, and plays an important role in knee joint rehabilitation training of patients.

The existing rehabilitation robots mostly adopt rigid driving modes such as hydraulic driving, direct motor driving and the like.

The lower limb exoskeleton rehabilitation robot with the servo motor is provided by Chinese patent CN202011415947.0, adopts the servo motor to drive and vertically arranges the motor, and can reduce the whole volume of the exoskeleton. However, the direct driving of the motor cannot ensure the flexibility and safety of the rehabilitation training of the patient, and even secondary injury is caused to the patient when an accident occurs. And based on the serial elastic driver formed by the elastic elements, the device can provide flexible auxiliary force and buffer impact, thereby meeting good man-machine interaction performance. The Wilia et al at university of St.Paul propose a flexible knee exoskeleton which adopts a rotary type serial elastic driver as a driving source and has the advantages of low output impedance, good man-machine interaction performance and the like. However, the backlash between the transmission gears of the rotary-type tandem elastic driver easily affects the stability of the control system, and the torsion spring used needs to be specially designed and customized, which is difficult to produce and manufacture.

A knee joint exoskeleton proposed by China patent CN 201810462531.0 adopts a flexible driving module composed of a flexible oil cylinder, wherein the flexible driving module adopts a linear type serial elastic driver, and a spring is placed in an air cylinder, so that the size of the linear type serial elastic driver is reduced. But can't install the deflection of sensor measurement spring in the hydro-cylinder inside, and then can't realize the accurate force control of driver, and need dismantle vice hydro-cylinder just can accomplish the change of spring, have the complex operation scheduling problem.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides the flexible knee joint exoskeleton rehabilitation robot which can realize flexible driving and has good driving stability and high driving force control accuracy.

The invention provides a flexible knee joint exoskeleton rehabilitation robot which comprises a thigh module, a shank module, a knee joint module and a flexible driving module, wherein the thigh module is rotationally connected with the shank module through the knee joint module, the driving end of the flexible driving module is connected with the shank module, the flexible driving module comprises a motor, a speed reducer, a screw rod, a spring fixing seat, a push rod driving assembly, a screw rod nut expansion plate and a displacement sensor, one end of the screw rod is connected to the output end of the motor through the speed reducer, the other end of the screw rod is in threaded connection with the screw rod nut expansion plate, the screw rod nut expansion plate is elastically arranged in the spring fixing seat, the bottom of the spring fixing seat is fixedly connected with one end of the push rod driving assembly, and the displacement sensor is fixedly arranged on the spring fixing seat and a sliding sheet of the displacement sensor is fixedly connected with the screw rod nut expansion plate.

More preferably, the spring fixing base comprises a first spring baffle, a second spring baffle and a spring length adjusting plate, the screw nut expansion plate is parallel to the first spring baffle and the second spring baffle, elastic members are arranged between the screw nut expansion plate and the first spring baffle and between the second spring baffle, the spring length adjusting plate is arranged on the first spring baffle and on the second spring baffle side, two ends of the spring length adjusting plate are respectively fixedly connected with the first spring baffle and the second spring baffle, and the displacement sensor is arranged on one side of the spring fixing base and two ends of the displacement sensor are respectively fixedly connected with the first spring baffle and the second spring baffle.

More preferably, the flexible driving module further comprises a first screw support, a second screw support, a first screw end bearing, a second screw end bearing, a first guide rail and a second guide rail, the first screw end bearing is fixedly connected with the first screw support, the second screw end bearing is fixedly connected with the second screw support, the first screw support is fixedly connected with the motor support, one end of the screw passes through the first screw end bearing in a tight fit manner, the other end of the screw passes through the second screw end bearing in a tight fit manner, the screw is fixedly connected with the speed reducer through a second coupling, the first guide rail and the second guide rail penetrate through the spring fixing seat and the screw nut expansion plate, one end of the screw nut expansion plate is fixedly connected with the motor support, the other end of the screw nut expansion plate is fixedly connected with the second screw support, and the spring fixing seat is in sliding fit with the first guide rail and the second guide rail.

More preferably, the push rod driving assembly comprises a first push rod, a second push rod, a push rod fixing plate and a rod end joint bearing or a tension pressure sensor, wherein the first push rod and the second push rod are mutually parallel and penetrate through the spring fixing seat and the screw nut expansion plate, one end of the first push rod and one end of the second push rod are fixedly connected with the spring fixing seat, the other end of the second push rod are fixedly connected with the push rod fixing plate, the screw nut expansion plate is in sliding fit with the first push rod and the second push rod, an elastic component is sleeved on the first push rod and the second push rod, and the bottom of the push rod fixing plate is fixedly connected with the rod end joint bearing or the tension pressure sensor;

when the bottom of the push rod fixing plate is connected with the rod end joint bearing, the rod end joint bearing is rotationally connected with the shank module through a third shoulder pin shaft;

when the bottom of the push rod fixing plate is connected with the pull pressure sensor, the top of the pull pressure sensor is fixedly connected with the bottom of the push rod fixing plate, the bottom of the pull pressure sensor is fixedly connected with the top of the pull pressure sensor connecting seat, and one side of the pull pressure sensor connecting seat is fixedly connected with the calf module.

More preferably, the knee joint module comprises an angle sensor bracket, a first coupling, an angle sensor, an anti-rotation piece and a first shoulder pin shaft, wherein the thigh module and the shank module are rotationally connected through the first shoulder pin shaft, one end of the angle sensor bracket is fixedly connected with the thigh module, the other end of the angle sensor bracket is fixedly connected with a shell of the angle sensor, a shaft lever of the angle sensor is fixedly connected with the shaft lever of the first shoulder pin shaft through the first coupling, the anti-rotation piece is embedded in a shaft hole of the shank module for assembling the first shoulder pin shaft, and the anti-rotation piece is in radial limit fit with the first shoulder pin shaft.

More preferably, the knee joint module further comprises a limiting pin, a limiting hole and a U-shaped limiting groove, wherein the U-shaped limiting groove is formed in the lower leg module, a plurality of limiting holes are formed in the thigh module, the limiting pin is arranged in one of the limiting holes, and the limiting pin can slide along the U-shaped limiting groove.

More preferably, the thigh module includes thigh driver support, thigh outer pole, thigh inner pole, thigh protective equipment module and second take shoulder round pin axle, thigh driver support with thigh outer pole mutually perpendicular, thigh outer pole with pole parallel arrangement in the thigh, thigh driver support one end is passed through the second takes shoulder round pin axle with flexible drive module rotates to be connected, the other end with the top of thigh outer pole links firmly, the bottom of thigh outer pole with the top of thigh inner pole links firmly, thigh inner pole bottom with knee joint module connects, thigh protective equipment module with the shaft of thigh outer pole links firmly, vertically on the thigh outer pole be equipped with the multiunit be used for connecting thigh driver support's driver support mounting hole, be used for connecting thigh inner pole mounting hole and be used for connecting thigh protective equipment module's thigh protective equipment module mounting hole, be equipped with the multiunit flexible drive module connection module along the horizontal direction on the thigh driver support.

More preferably, the shank module includes shank driver support, shank outer pole, shank inner pole, shank protective equipment module to and third shoulder round pin axle or pull pressure sensor connecting seat, shank driver support with shank inner pole mutually perpendicular, shank outer pole with shank inner pole parallel arrangement, shank driver support one end is passed through third shoulder round pin axle with flexible drive module's drive end swivelling joint, or pass through pull pressure sensor connecting seat with flexible drive module's drive end fixed connection, shank driver support other end with shank inner pole's upper portion links firmly, shank inner pole's lower part with shank outer pole's upper portion links firmly, shank protective equipment module with shank outer pole's shaft links firmly, shank driver support is last to be equipped with the multiunit in shank inner pole mounting hole that is used for connecting shank inner pole along the horizontal direction, be equipped with on the shank inner pole along vertically multiunit leg outer pole is used for connecting shank outer pole, multiunit knee protector module is equipped with in the multiunit knee protector inner pole is used for connecting shank inner pole, the multiunit knee protector module is used for connecting with the shank inner pole is equipped with the inner joint hole.

Preferably, the leg support device further comprises a leg support module and/or an external support frame module, wherein the leg support module is detachably connected to the bottom of the lower leg module, and the external support frame module is detachably connected with the thigh module.

More preferably, the thigh protective device module comprises an arc-shaped hoop and a fastening tape, wherein the arc-shaped hoop is fixedly connected with the thigh outer rod, and one end of the fastening tape is fixedly arranged on the arc-shaped hoop.

The beneficial effects of the invention are as follows:

1. the screw nut expansion plate of the flexible driving module is elastically arranged in the spring fixing seat, the bottom of the spring fixing seat is fixedly connected with one end of the push rod driving assembly, the displacement sensor is fixedly arranged on the spring fixing seat, and the sliding sheet of the displacement sensor is fixedly connected with the screw nut expansion plate. The flexible driving is realized through elastic force, and the flexible driving device has the advantages of good stability, large output force, low impedance, high safety and flexibility. And the displacement sensor is fixedly arranged on the spring fixing seat, and the sliding sheet of the displacement sensor follows the displacement of the screw nut expansion plate, so that the monitoring of the deformation quantity of the spring can be realized, and the accurate force control of the driver is realized. And the spring replacement only needs to detach the spring fixing seat, so that the maintenance is more convenient.

2. The bottom of the push rod driving assembly can be connected with a rod end joint bearing or a tension pressure sensor in an adaptive manner, when the rod end joint bearing is connected, normal rotation of the knee joint exoskeleton rehabilitation robot can be realized, when the tension pressure sensor is connected, the knee joint exoskeleton rehabilitation robot is kept static, at the moment, the flexible driving module is equivalent to a calibration platform of the spring elastic coefficient, the deformation of the spring can be obtained through the displacement sensor, and the elasticity of the spring can be obtained through the tension pressure sensor, so that the calibration of the spring elastic coefficient is realized.

3. The knee joint module angle sensor support, angle sensor, anti-rotation piece, take shoulder round pin axle, spacer pin, spacing hole and U type spacing groove, angle sensor's shell passes through angle sensor support and thigh module to be linked firmly, and the axostylus axostyle passes through the shaft coupling and links firmly with taking shoulder round pin axle, realizes that angle sensor pivoted angle is the same with the relative turned angle of thigh interior pole and shank interior pole, has higher measurement accuracy. Through the mode that spacer pin, spacing hole and U type spacing groove mutually support, realized joint rotation angle's regulation and spacing. Radial limiting of the shoulder pin shaft is achieved through the arrangement of the anti-rotation piece. The rotation smoothness and stability of the whole knee joint module are ensured.

4. The adjustability of the assembly positions is realized among all the components of the thigh module and the shank module through a plurality of groups of mounting holes, so that the device can be adapted to users with different body types, and has good suitability and universality.

Drawings

FIG. 1 is a schematic view of the structure of the present invention (without the external support frame module);

FIG. 2 is a schematic view of the structure of the present invention (including an external support frame module);

FIG. 3 is a schematic diagram of the connection of the thigh module to the calf module of the present invention;

FIG. 4 is a schematic diagram of a flexible driving module according to the present invention;

FIG. 5 is a schematic structural view of a first connection of the push rod driving assembly according to the present invention;

FIG. 6 is a schematic view of a second connection of the push rod driving assembly of the present invention;

FIG. 7 is a schematic view of a knee joint module of the present invention;

FIG. 8 is a schematic view of an exploded view of a knee module of the present invention;

FIG. 9 is a schematic view of the thigh brace module of the invention;

FIG. 10 is a schematic diagram of an arrangement of the light sensor of the present invention;

FIG. 11 is a schematic diagram of a dual-flow neural network of the present invention;

fig. 12 is a flow chart of the overall exoskeleton control method of the present invention.

Detailed Description

In order to make the technical problems, technical schemes and beneficial effects to be solved by the present application more clear, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the present application.

It will be understood that when an element is referred to as being "mounted" or "disposed" on another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.

It is to be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate or are based on the orientation or positional relationship shown in the drawings, merely to facilitate description of the present application and simplify description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be configured and operated in a particular orientation, and therefore should not be construed as limiting the present application.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

Reference in the specification to "one embodiment" or "some embodiments" or the like means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," and the like in the specification are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments" unless expressly specified otherwise. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless expressly specified otherwise. "plurality" means "two or more".

Example 1

Fig. 1 and 2 show schematic structural views of a flexible knee exoskeleton rehabilitation robot according to a preferred embodiment of the present application, and for convenience of explanation, only the portions related to the present embodiment are shown, which are described in detail below:

a flexible knee joint exoskeleton rehabilitation robot comprises a thigh module 1, a shank module 2, a knee joint module 3, a flexible driving module 4, a foot rest module 5 and an external support frame module 6. The thigh module 1 and the shank module 2 are rotationally connected through the knee joint module 3, and the driving end of the flexible driving module 4 is connected with the shank module 2. The foot support module 5 is detachably connected to the bottom of the lower leg module 2, and the outer support frame module 6 is detachably connected with the thigh module 1.

As shown in fig. 3, the thigh module 1 comprises a thigh driver support 11, a thigh outer rod 12, a thigh inner rod 13, a thigh brace module 14, a second shoulder pin 15; the thigh driver support 11 is provided with three large round holes and two small round holes, the connection position of the thigh driver support and the flexible driving module 4 can be adjusted, the second shoulder pin shaft 15 passes through the round holes and the driver round holes and is locked by nuts, and the flexible driving module 4 is in rotary connection with the thigh module 1; two round holes are formed in the right side of the thigh driver support 11, the thigh outer rods 12 are aligned with the small round holes of the thigh driver support 11 in pairs, and the thigh outer rods are fixedly connected through two screws penetrating through the round holes and matched nuts; the thigh outer rod 12 is provided with a plurality of groups of 2 round holes, and the positions of the thigh outer rod 12, the thigh inner rod 13 and the thigh outer rod 12 connected with the thigh driver support 11 can be adjusted to meet different driving requirements and wearing requirements; the thigh outer rod 12 is provided with a plurality of groups of 4 small round holes, screws penetrate through the round holes and the corresponding 4 round holes on the thigh guard module 14, so that the thigh outer rod 12 is connected with the thigh guard module 14, and the position of the thigh guard module 14 can be adjusted according to the thickness of the thigh of a patient.

The lower leg module 2 comprises a lower leg driver support 21, an lower leg outer rod 22, a lower leg inner rod 23, a lower leg protector module 24, a third shoulder pin 25 and a pull pressure sensor connecting seat 26; the lower leg driver support 21 is provided with a large round hole, and can be connected with the flexible driving module 4 by matching with a third shoulder pin shaft 25 or a tension pressure sensor connecting seat 26; the lower leg driver support 21 is provided with a plurality of groups of 2 round holes, the lower leg inner rod 23 is provided with two round holes with the same diameter and the same interval, the two round holes are aligned with each other, the two round holes are fixedly connected through two screws penetrating through round hole matching nuts, and the connection position of the lower leg driver support 21 and the lower leg inner rod 23 can be realized by adjusting the alignment position of the round holes so as to meet different driving requirements; the outer shank rod 22 is provided with a plurality of groups of 2 round holes, the inner shank rod 23 is provided with two round holes with the same diameter and interval, two screws simultaneously penetrate through the round holes aligned on the outer shank rod 22 and the inner shank rod 23 to realize the fixed connection of the two, the connection positions of the two can be changed by adjusting the alignment positions of the round holes, the adjustment of the shank rod length is realized, and the wearing requirements of patients with different sizes are met; the outer shank 22 is provided with a plurality of groups of 4 small round holes, the 4 small round holes are in diamond design, 4 screws penetrate through the group of round holes and the corresponding 4 round holes on the shank protector module 24, connection between the outer shank 22 and the shank protector module 24 is achieved, and the position of the shank protector module 24 can be adjusted according to the thickness of the shank of a patient.

FIG. 4 is a schematic diagram of a flexible drive module, wherein a motor 41 is connected with a speed reducer 42 to increase the output torque; the shaft side of the speed reducer 42 is provided with a threaded hole, and the speed reducer 42 is fixed on the motor support 43 through a screw; the first screw end bearing 45a is fixedly connected with the first screw support 46a through a screw, the second screw end bearing 45b is fixedly connected with the second screw support 46b through a screw, and the first screw support 46a is fixedly connected with the motor support 43 through a screw; one end of the screw 48 (ball screw) passes through the first screw end bearing 45a in a tight fit manner, and the other end passes through the second screw end bearing 45b in the same manner; one end of the second coupler 44 is connected with the shaft lever of the speed reducer 42, the other end is connected with the shaft lever of the ball screw 48, and the screw rod is locked by tightening the screw on the coupler; one end of the first guide rail 47a and one end of the second guide rail 47b are provided with threads, the threads are inserted into round holes in the second screw support 46b and are fixedly connected through nuts, and the other end of the threads are inserted into round holes in the motor support 43 and are fixedly connected through tight fit; one end of the first push rod 413a and one end of the second push rod 413b are provided with screw threads, the screw threads are inserted into a round hole in the first spring baffle 49a and are fixedly connected through nuts, the other end of the screw threads are inserted into a round hole in the push rod fixing plate 414 and are fixedly connected through tight fit, the push rod fixing plate 414 is provided with a threaded hole, and a rod end joint bearing 415 or a screw rod on the pull pressure sensor 416 passes through the threaded hole of the push rod fixing plate 414 to be fixedly connected with the first push rod and the second push rod; the first spring baffle 49a is provided with round holes penetrating through the first guide rail 47a and the second guide rail 47b, the screw nut expansion plate 412 is fixedly connected with the screw nut 410 through screws, four corners of the screw nut expansion plate 412 and the second spring baffle 49b are provided with round holes penetrating through the first guide rail 47a, the second guide rail 47b, the first push rod 413a and the second push rod 413b respectively; the 4 springs 411 are respectively arranged on a first push rod 413a between the first spring baffle 49a and the screw nut expansion plate 412, a first push rod 413a between the second spring baffle 49b and the screw nut expansion plate 412, a second push rod 413b between the first spring baffle 49a and the screw nut expansion plate 412 and a second push rod 413b between the second spring baffle 49b and the screw nut expansion plate 412; the spring length adjusting plate 417 is fixedly connected with the first spring baffle 49a and the second spring baffle 49b through screws to realize precompression of the springs, and one side of the spring length adjusting plate 417 is provided with an oblong hole, so that the connection position with the second spring baffle 49b can be adjusted to realize adjustment of precompression length of the springs; the displacement sensor 418 is respectively fixed on the first spring baffle 49a and the second spring baffle 49b through screws, two clamping pieces are arranged on the screw nut expansion plate 412, concave grooves are formed in the clamping pieces, a sliding block of the displacement sensor is inserted into the concave grooves in the two clamping pieces and is locked by the screws, and when the springs deform, the sliding block of the displacement sensor moves along with the clamping pieces.

As shown in fig. 5 and 6, the flexible driving module 4 and the lower leg module 2 are connected in two ways, namely, a rotating connection in fig. 4a and a fixed connection in fig. 4 b; as shown in fig. 4a, the end of the push rod fixing plate 414 of the flexible driving module is connected with the rod end joint bearing 415 through a threaded hole, the third shoulder pin shaft 25 simultaneously passes through the bearing hole of the rod end joint bearing 415 and the round hole of the lower leg driver support 21 and is fixed through a nut, and the rod end joint bearing 415 and the lower leg driver support 21 can rotate relatively; as shown in fig. 4b, the pull pressure sensor connecting seat 26 is provided with a threaded hole with the same diameter as the pull pressure sensor screw rod, and is also provided with a threaded rod with the same diameter as the round hole of the shank driver support 21, the upper end of the push rod fixing plate 414 of the flexible driving module is connected with the upper end screw rod of the pull pressure sensor 416 through a threaded hole, the lower end screw rod of the pull pressure sensor 416 is fixedly connected with the threaded hole of the pull pressure sensor connecting seat 26, and the threaded rod of the pull pressure sensor connecting seat 26 passes through the round hole of the shank driver support 21 and is fixedly connected with the shank driver support 21 through a nut; when the flexible driving module 4 and the lower leg module 2 are rotationally connected, the knee joint exoskeleton rehabilitation robot can normally rotate; when the flexible driving module 4 and the lower leg module 2 are fixedly connected, the knee joint exoskeleton rehabilitation robot keeps static, at the moment, the flexible driving module is equivalent to a calibration platform of the spring elastic coefficient, the deformation of the spring can be known through the displacement sensor, and the elasticity of the spring can be known through the tension pressure sensor, so that the calibration of the spring elastic coefficient is realized.

As shown in fig. 7 and 8, the knee joint module 3 includes an angle sensor bracket 31, a first coupler 32, an angle sensor 33, an anti-rotation piece 34, a limiting device, a limiting pin 35-1, a limiting hole 35-2, a U-shaped limiting groove 35-3, and a first shoulder pin 36; the first shoulder pin shaft 36 passes through round holes of the thigh inner rod 13 and the shank inner rod 23 to realize the rotary connection of the thigh module 1 and the shank module 2, and the axial side distance between the thigh inner rod 13 and the shank inner rod 23 is adjusted through a nut; one end of the angle sensor bracket 31 is fixedly connected to the thigh inner rod 13 through a screw, and the other end is fixedly connected with the angle sensor 33 through a screw matched with a threaded hole on the outer shell of the shaft side of the angle sensor 33; the lower leg inner rod 23 is provided with a square groove, the anti-rotation piece 34 is locked in the groove through a screw, and is used for preventing the lower leg inner rod 23 and the first shoulder pin shaft 36 from rotating relatively, so that the lower leg inner rod 23 and the first shoulder pin shaft 36 are kept relatively static, and only the thigh inner rod 13 and the first shoulder pin shaft 36 rotate, so that the thigh module 1 and the lower leg module 2 rotate relatively; one end of the first coupling 32 is connected with the shaft lever of the first shoulder pin shaft 36, and the other end is connected with the shaft lever of the angle sensor 33, so that the shaft lever of the angle sensor 33 and the lower leg inner rod 23 are kept relatively static, and the shell of the angle sensor 33 and the lower leg inner rod 13 are kept relatively static due to the fact that the angle sensor bracket 31 is fixed on the lower leg inner rod 13, and the rotating angle of the angle sensor 33 is ensured to be the same as the rotating angle of the lower leg inner rod 23 and the upper leg inner rod 13; the knee joint module 3 is also provided with a limiting device 35, the lower leg inner rod 23 is provided with a U-shaped limiting groove 35-3, the thigh inner rod 13 is provided with a plurality of limiting holes 35-2, the limiting pins 35-1 are inserted into the limiting holes 35-2 in a tight fit mode, and the limited joint rotation angle can be adjusted by changing the positions of the limiting pins 35-1.

As shown in fig. 9, the thigh guard module 14 is exemplified by an arc-shaped hoop 14-1 and a fastening tape 14-2, wherein the arc of the arc-shaped hoop 14-1 is fit with the arc of the leg of the human body, and four small round holes are formed in the arc-shaped hoop 14-1 and are used for being connected with the thigh outer rod 12; the two ends of the arc-shaped hoop 14-1 are provided with oblong holes, the fastening tape 14-2 passes through one oblong hole and bypasses the thigh of the patient and passes through the other oblong hole, and the fastening tape 14-2 is tightened to tightly fix the thigh of the patient and the thigh protector module 14.

The working principle of the device is as follows:

the motor 41 rotates under the control of the controller system, the ball screw 48 is driven to rotate after the speed is reduced by the speed reducer 42, the screw nut 410 moves linearly and deforms the spring 411, under the action of spring force, the push rods 413a and 413b are pulled to move linearly, the push rods pull the shank rod and the thigh rod to rotate relatively, the knee joint flexion and extension movement is achieved, meanwhile, the flexible driving module 4 rotates relatively with the thigh driver support 11 and the shank driver support 21 in a small amplitude, and the displacement sensor records the deformation quantity of the spring, and the angle sensor records the knee joint flexion and extension angle and feeds back to the control system.

The encoder of the flexible knee joint exoskeleton rehabilitation robot is arranged at the top of the motor to record the speed and the position of the motor, the displacement sensor is arranged at two ends of the spring to measure the deformation quantity of the spring and calculate the output force of the driver, and the angle sensor is arranged at the knee joint to measure the rotation angle of the knee joint. The motor controller collects data of the encoder, the displacement sensor and the angle sensor, the data are transmitted to the upper computer through Labview software, and the upper computer processes and analyzes the sensor data according to corresponding control strategies, so that the motor controller outputs current signals to enable the motor to rotate, and further knee joint movement is driven.

In one embodiment, the modules of the device may be removable for selection based on the rehabilitation session.

In the early stage of rehabilitation, an external support frame module and a foot rest module can be selectively assembled, and the weight of a patient is supported by the two modules in a matched mode;

an external support frame module or a foot rest module can be selected to support part of the weight of the patient (namely, one of the modules is removed) in the middle rehabilitation period;

and the external support frame module and the foot rest module are disassembled at the later period of rehabilitation, so that the maximum voluntary rehabilitation of the patient is realized.

In one embodiment, the device is used in combination with a flexible sensor module, wherein the flexible sensor module comprises a myoelectric sensor and a flexible optical fiber sensor, and skin-adhering acquisition of data can be realized. And collecting electromyographic signals and optical fiber deformation signals of the lower limbs of the subject through the flexible sensor module.

As shown in fig. 10, the optical fiber sensor increases the number of bonding sites near the knee bending region, so that the sensitivity of the sensor is increased, in order to prevent the optical fiber from being broken by the deformation of the surface when the optical fiber is subjected to bending deformation, the design plan adopts a loop wiring mode, so that the tangential direction of the optical fiber at the bonding position is perpendicular to the direction of the fabric length change caused by bending, and the loop wiring mode can also obtain more sampling points in the sampling region under the condition that the curvature radius is not small. The optical fiber in the sensor has 5 loop bends, and the curvature radius is generally designed to be 6.5-8.5 mm, so that the problem that the measurement effect is poor due to overlarge optical loss caused by too small curvature radius is avoided.

In one embodiment, the joint angle at the next moment is predicted through a double-flow neural network, and the auxiliary force is provided in advance to drive the patient to recover. As shown in fig. 11, the gait trajectory prediction algorithm predicts the joint angle at the next moment by using the myoelectric signal and the optical fiber deformation through the dual-flow neural network, wherein the first-layer neural network comprises a CNN module, a spatial attention module, a temporal attention module, and an LSTM module, the second-layer neural network comprises an LSTM module and an attention module, and finally, the prediction result is output by weighting and summing the two-layer neural networks.

Wherein the first layer neural network time attention module pools feature vectors through a global averaging layerDimension slaveMapping to +.>And adjust the feature dimension to +.>Performing multiplication operation with the original feature matrix, and then obtaining a time attention weight vector through a sigmoid function; the spatial attention module dimension-wise-feature vectors from the global averaging pooling layerMapping to +.>And adjust the feature dimension to +.>And carrying out multiplication operation on the space attention weight vector and the original feature matrix, and then obtaining the space attention weight vector through a sigmoid function. The first module is a CNN feature extraction module, which includes a convolution layer for extracting high-dimensional features of the original data. The second module is a spatial attention module, features output to CNN pass through an average pooling layer and a maximum pooling layer respectively, and feature vector dimensions are reduced from +.>Mapping toAnd then splicing the pooled feature graphs, obtaining a space attention weight vector through a convolution layer and a sigmoid function, and multiplying the space attention weight vector with the original features element by element to output the feature vector. The third module is a time attention module, the characteristics of time attention output pass through a global average pooling layer, and then the pooled characteristic vector dimension is from +. >Mapping toThen pass through a convolution layer and adjust the feature dimension to +.>And then obtaining a time attention weight vector through a sigmoid function, and multiplying the time attention weight vector with the original feature matrix element by element to output a feature vector. The fourth module is an LSTM prediction module, which comprises an LSTM network layer and a flat layer, and is used for capturing sequence mode information, carrying out regression analysis and unidimensional data. The main network parameters are as follows:

table 1: neural network parameters

The second layer neural network obtains the attention weight vector through the softmax function, and then performs weighted calculation on all hidden layer units and the attention weight, wherein the formula is as follows:

wherein the method comprises the steps ofFeature dimension output for LSTM hidden layer, < >>For attention weight, ++>A weighted sum of all hidden layer units and their corresponding attention weights for the encoder.

And then carrying out weighted summation on the output of the double-flow neural network to obtain a final prediction result, wherein the formula is as follows:

wherein the method comprises the steps ofFor final output result, ++>Two layers of neural network weights respectively, +.>And outputting results for the two layers of neural networks respectively.

FIG. 12 is a flow chart of the overall exoskeleton control method of the present invention, which is an adaptive impedance algorithm to predict gait trajectories For reference, a flexible knee joint exoskeleton self-adaptive impedance controller is designed based on an artificial potential field method, and the exoskeleton movement range is limited in a coordination space, and the formula is as follows:

wherein,to make an object at a certain point->Is>As a function of the force potential->To repulsive forcePotential function->Is gravitation gain factor>Representing the Euclidean distance of the object from the target point, +.>In order for the repulsive force to be a gain factor,representing the Euclidean distance between the object and the obstacle, < >>Representing the maximum distance of action of the repulsive field generated by the obstacle.

The gait track is enabled to accord with the healthy-affected side coordinated motion law as much as possible while the human-computer interaction flexibility is ensured, and the self-adaptive adjustment formula of the impedance parameter is designed as follows:

wherein the method comprises the steps of、/>、/>Respectively represent inertia coefficient->Damping coefficient->Rigidity coefficient->The initial value set,/->Is indicated at->The magnitude of the potential function of the moment,/->、/>、/>Representing the positive number weight acting on the potential function. The potential function is smaller and changes slower when the object is closer to the target, i.e., the desired trajectory deviates less from the optimal coordinated gait trajectory, and is larger and changes faster when the object is farther from the target, i.e., the desired trajectory deviates more from the optimal coordinated gait trajectory. When approaching the boundary, the repulsive force potential function approaches infinity, so that the object is ensured not to cross the boundary.

A flexible knee exoskeleton position-based impedance control structure is presented in which the feedback force is derived from the spring rate times the amount of spring compression. When the actual man-machine interaction force is as desiredWhen the man-machine interaction force is equal, the force feedback outer ring fails at the moment, and the exoskeleton moves according to the original expected track under the action of the position control inner ring. When the actual man-machine interaction force is not equal to the expected man-machine interaction force, the force feedback outer ring is used for controlling the force feedback outer ring to output a force according to the difference value of the actual man-machine interaction force and the expected man-machine interaction forceCalculating the correction value of the desired track +.>And correcting the original expected track, and tracking the corrected track by the robot under the action of the position control inner ring to move. Therefore, when the intention of the patient side movement is inconsistent with the actual movement of the exoskeleton, the actual human interaction force and the expected human interaction force deviate, so that the exoskeleton carries out expected track adjustment to conform to the movement intention of a patient, and the safe and flexible control effect is achieved.

The wearable sensor monitors the motion information of the patient in real time, obtains the current state of the patient based on various motion data analysis, triggers the exoskeleton balance recovery control strategy when detecting that the patient has a falling trend, rapidly applies the assistance moment to the knee joint of the patient, and enables the patient to recover the self balance, thereby achieving the purpose of falling avoidance.

Wherein the method comprises the steps of、/>Is the mass of thigh and shank, +.>、/>Is the barycenter position of thigh and calf, < ->、/>Respectively comprises an included angle between thighs and the horizontal plane, an included angle between the lower legs and the horizontal plane, and +.>Is a muscle tension arm>And->The thigh length and the calf length are respectively,Is the vector diameter of the mass center. Wherein->The ankle moment is the product of the plantar pressure value at the ankle joint and the distance from the ankle joint to the toe root. />Is the knee joint moment which the exoskeleton wearer should achieve under normal walking conditions.

Calculating a balance restoring moment at the knee joint according to the exoskeleton wearer motion information and the limb parameters:

wherein the method comprises the steps ofTo balance the restoring moment>Is a torque assist coefficient.

The bending angle of the knee joint is 0-60 degrees when the human body walks normally, and the bending degree of the knee joint can be increased when the human body falls down until the human body exceeds the normal range. Weakness of lower limbs when patients have a tendency to fallThe moment of the knee joint can not reach the normal moment range, and the real-time motion information and the moment auxiliary coefficient of the patient at the momentThere is a non-linear mapping between them. By fuzzy logic reasoning, the moment auxiliary coefficient is built by combining the moment which the patient should reach and the acceleration, angular velocity, angle and plantar pressure obtained by the inertia measuring unit +. >By calculation, the compensation moment exerted by the exoskeleton on the knee joint, i.e. the balancing restoring moment +.>. And triggering an exoskeleton balance restoration control strategy after predicting that the falling action is about to occur, and enabling the exoskeleton to provide assistance according to a preset balance restoration moment value so as to enable the knee joint angle to return to a normal range.

The above embodiments are only for illustrating the technical solution of the present application, and are not limiting; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application, and are intended to be included in the scope of the present application.

Claims

1. A flexible knee joint ectoskeleton rehabilitation robot which is characterized in that: including thigh module (1), shank module (2), knee joint module (3) and flexible drive module (4), thigh module (1) with pass through between shank module (2) knee joint module (3) rotate and connect, the drive end of flexible drive module (4) with shank module (2) are connected, flexible drive module (4) include motor (41), reduction gear (42), lead screw (48), spring fixing base, push rod drive assembly, lead screw nut expansion board (412) and displacement sensor (418), lead screw (48) one end is connected to motor (41) output through reduction gear (42), the lead screw (48) other end with lead screw nut expansion board (412) threaded connection, lead screw nut expansion board (412) elasticity set up in the spring fixing base, spring fixing base bottom with push rod drive assembly one end links firmly, displacement sensor (418) set firmly on the spring fixing base, just the gleitbretter of displacement sensor (418) with lead screw nut expansion board (412) fixed connection.

2. The flexible knee exoskeleton rehabilitation robot of claim 1, wherein: the spring fixing seat comprises a first spring baffle (49 a), a second spring baffle (49 b) and a spring length adjusting plate (417), the screw nut extending plate (412) is arranged between the first spring baffle (49 a) and the second spring baffle (49 b) in parallel, elastic components are arranged between the screw nut extending plate (412) and the first spring baffle (49 a) and between the screw nut extending plate and the second spring baffle (49 b), the spring length adjusting plate (417) is arranged on one side of the first spring baffle (49 a) and one side of the second spring baffle (49 b), two ends of the spring length adjusting plate (417) are respectively fixedly connected with the first spring baffle (49 a) and the second spring baffle (49 b), and the displacement sensor (418) is arranged on one side of the spring fixing seat and two ends of the displacement sensor (418) are respectively fixedly connected with the first spring baffle (49 a) and the second spring baffle (49 b).

3. The flexible knee exoskeleton rehabilitation robot of claim 1, wherein: the flexible driving module (4) further comprises a first screw support (46 a), a second screw support (46 b), a first screw end bearing (45 a), a second screw end bearing (45 b), a first guide rail (47 a) and a second guide rail (47 b), the first screw end bearing (45 a) is fixedly connected with the first screw support (46 a), the second screw end bearing (45 b) is fixedly connected with the second screw support (46 b), the first screw support (46 a) is fixedly connected with the motor support (43), one end of the screw (48) penetrates through the first screw end bearing (45 a) in a tight fit mode, the other end of the screw (48) penetrates through the second screw end bearing (45 b) in a tight fit mode, the screw (48) is fixedly connected with the speed reducer (42) through a second coupler (44), the first guide rail (47 a) and the second guide rail (47 b) penetrate through the spring fixing seat and the nut expansion plate (412), one end of the screw (48) is fixedly connected with the motor support (43), and the other end of the screw (48) is fixedly connected with the second guide rail (47 b) and the first guide rail (47 b) in a tight fit mode.

4. The flexible knee exoskeleton rehabilitation robot of claim 1, wherein: the push rod driving assembly comprises a first push rod (413 a), a second push rod (413 b), a push rod fixing plate (414) and a rod end joint bearing (415) or a pull pressure sensor (416), wherein the first push rod (413 a) and the second push rod (413 b) are mutually parallel and penetrate through the spring fixing seat and the screw rod nut expansion plate (412), one end of the first push rod (413 a) and one end of the second push rod (413 b) are fixedly connected with the spring fixing seat, the other end of the second push rod is fixedly connected with the push rod fixing plate (414), the screw rod nut expansion plate (412) is in sliding fit with the first push rod (413 a) and the second push rod (413 b), an elastic component is sleeved on the first push rod (413 a) and the second push rod (413 b), and the bottom of the push rod fixing plate (414) is fixedly connected with the rod end joint bearing (415) or the pull pressure sensor (416);

when the bottom of the push rod fixing plate (414) is connected with the rod end joint bearing (415), the rod end joint bearing (415) is rotationally connected with the calf module (2) through a third shoulder pin shaft (25);

When the bottom of the push rod fixing plate (414) is connected with the pull pressure sensor (416), the top of the pull pressure sensor (416) is fixedly connected with the bottom of the push rod fixing plate (414), the bottom of the pull pressure sensor (416) is fixedly connected with the top of the pull pressure sensor connecting seat (26), and one side of the pull pressure sensor connecting seat (26) is fixedly connected with the lower leg module (2).

5. The flexible knee exoskeleton rehabilitation robot of claim 1, wherein: the knee joint module (3) comprises an angle sensor bracket (31), a first coupler (32), an angle sensor (33), an anti-rotation piece (34) and a first shoulder pin shaft (36), wherein the thigh module (1) and the shank module (2) are rotationally connected through the first shoulder pin shaft (36), one end of the angle sensor bracket (31) is fixedly connected with the thigh module (1), the other end of the angle sensor bracket is fixedly connected with a shell of the angle sensor (33), a shaft lever of the angle sensor (33) is fixedly connected with a shaft lever of the first shoulder pin shaft (36) through the first coupler (32), the anti-rotation piece (34) is embedded in a shaft hole of the shank module (2) for assembling the first shoulder pin shaft (36), and the anti-rotation piece (34) is in radial limit fit with the first shoulder pin shaft (36).

6. The flexible knee exoskeleton rehabilitation robot of claim 5, wherein: the knee joint module (3) further comprises a limiting pin (35-1), a limiting hole (35-2) and a U-shaped limiting groove (35-3), the U-shaped limiting groove (35-3) is formed in the lower leg module (2), a plurality of limiting holes (35-2) are formed in the thigh module (1), the limiting pin (35-1) is arranged in one of the limiting holes (35-2), and the limiting pin (35-1) can slide along the U-shaped limiting groove (35-3).

7. The flexible knee exoskeleton rehabilitation robot of claim 1, wherein: thigh module (1) are including thigh driver support (11), thigh outer pole (12), thigh inner pole (13), thigh protective equipment module (14) and second take shoulder round pin axle (15), thigh driver support (11) with thigh outer pole (12) mutually perpendicular, thigh outer pole (12) with pole body parallel arrangement in thigh inner pole (13), thigh driver support (11) one end is passed through second takes shoulder round pin axle (15) with flexible drive module (4) rotate to be connected, the other end with the top of thigh outer pole (12) links firmly, the bottom of thigh outer pole (12) with the top of thigh inner pole (13) links firmly, thigh inner pole (13) bottom with knee joint module (3) are connected, thigh protective equipment module (14) with the pole body of thigh outer pole (12) links firmly, vertically on thigh outer pole (12) be equipped with along being used for connecting thigh driver support (11) in multiunit thigh driver support (14) the horizontal drive module of thigh driver support (4) and be used for connecting in the flexible drive module mounting hole of thigh driver module (14.

8. The flexible knee exoskeleton rehabilitation robot of claim 1, wherein: the lower leg module (2) comprises a lower leg driver support (21), a lower leg outer rod (22), a lower leg inner rod (13), a lower leg protector module (24) and a third shoulder pin shaft (25) or a pull pressure sensor connecting seat (26), wherein the lower leg driver support (21) is mutually perpendicular to the lower leg inner rod (13), the lower leg outer rod (22) is arranged in parallel with the lower leg inner rod (13), one end of the lower leg driver support (21) is rotationally connected with the driving end of the flexible driving module (4) through the third shoulder pin shaft (25), or is fixedly connected with the driving end of the flexible driving module (4) through the pull pressure sensor connecting seat (26), the other end of the lower leg driver support (21) is fixedly connected with the upper part of the lower leg inner rod (13), the lower leg protector module (24) is fixedly connected with the upper part of the lower leg outer rod (22), a plurality of groups of lower leg outer rods (22) are fixedly connected with the lower leg inner rods (13) along the longitudinal direction of the lower leg inner rods (13) along the lower leg inner rods (13), the leg protector is characterized in that a plurality of groups of leg protector module mounting holes for connecting the leg protector modules (24) and a plurality of groups of second leg inner rod mounting holes for connecting the leg inner rods (13) are longitudinally formed in the leg outer rods (22), and the tops of the leg inner rods (13) are connected with the knee joint modules (3).

9. The flexible knee exoskeleton rehabilitation robot of claim 1, wherein: the leg support device is characterized by further comprising a leg support module (5) and/or an external support frame module (6), wherein the leg support module (5) is detachably connected to the bottom of the lower leg module (2), and the external support frame module (6) is detachably connected with the thigh module (1).

10. The flexible knee exoskeleton rehabilitation robot of claim 7, wherein: the thigh protective device module (14) comprises an arc-shaped hoop (14-1) and a fastening tape (14-2), wherein the arc-shaped hoop (14-1) is fixedly connected with the thigh outer rod (12), and one end of the fastening tape (14-2) is fixedly arranged on the arc-shaped hoop (14-1).