CN110652425B

CN110652425B - Variable-rigidity lower limb exoskeleton power-assisted robot

Info

Publication number: CN110652425B
Application number: CN201910768255.5A
Authority: CN
Inventors: 吴青聪; 朱杨辉; 陈柏; 陈喜; 徐大文
Original assignee: Nanjing University of Aeronautics and Astronautics
Current assignee: Nanjing University of Aeronautics and Astronautics
Priority date: 2019-08-20
Filing date: 2019-08-20
Publication date: 2021-12-17
Anticipated expiration: 2039-08-20
Also published as: CN110652425A

Abstract

The invention discloses a variable-rigidity lower limb exoskeleton power-assisted robot which is worn on lower limbs of a human body and comprises a waist mechanism, a hip mechanism and a knee mechanism, wherein the waist mechanism is connected with the hip mechanism; the driving motor and the driving disc on the waist mechanism are used as driving sources, the driving lasso is driven to rotate forwards or backwards, the input disc of the knee mechanism below is driven to rotate forwards or backwards, and the input disc rotates relative to the output disc to drive the knee joint to rotate. A pulley and a steel wire rope are adopted between an input disc and an output disc of the knee mechanism to form a variable stiffness adjusting function. And the rigidity range of the joint can be increased or decreased by adjusting the number of the pulley sets, and the rigidity characteristic of the joint is changed. When the variable stiffness mechanism is used for driving, the stiffness can be actively changed in the walking process, so that the exoskeleton has the advantages of better flexibility, higher safety, better adaptability and compact and simple mechanism.

Description

Variable-rigidity lower limb exoskeleton power-assisted robot

Technical Field

The invention belongs to the field of robots, and particularly relates to an exoskeleton robot which aims to enhance the knee joint movement ability of a wearer, provide lower limb walking assistance or assist patients with lower limb dyskinesia to perform rehabilitation training and treatment.

Background

With the development of modern society, the aging problem of the population in China is gradually serious, and as the old people generally have the phenomena of insufficient physical strength and insufficient walking force, even a part of people are inconvenient to walk due to stroke and traffic accidents, the problems bring huge pressure and burden to families. Therefore, a wearable, comfortable and portable lower limb exoskeleton robot is needed to be researched, provides walking assistance for the old and has great value and potential for assisting rehabilitation treatment of stroke patients.

The existing lower limb assistance exoskeleton robot has various defects, for example, a driver is directly connected to a joint, so that the safety is low, secondary injury is easily caused to a user, the mass of a leg is too large due to the driving mode, the inertia of the leg is increased, and the energy consumption in the motion process is increased. In addition, the existing power-assisted exoskeleton adopts rigid joints or series elastic joints with invariable rigidity, so that the flexibility is difficult to ensure, the use safety is not high enough, and the existing power-assisted exoskeleton is difficult to adapt to complex motion environments.

In chinese patent application No. 201610511532.0, a lower extremity assisted exoskeleton robot is disclosed that includes an upper body structure, a leg structure, a knee joint, and a hip joint. The hip joint and the knee joint are directly driven by the double motors, and the motors are arranged at the joints, so that the joints have large mass and inertia, poor joint flexibility and poor safety.

In chinese patent application No. 201610099877.X, an energy-saving semi-passive lower extremity exoskeleton based on lasso drive is disclosed, which comprises a hip joint mechanism, a knee joint mechanism, and an ankle joint mechanism. The mechanism is driven by using the lasso, so that the problems of high mass and inertia of the joint are effectively solved, but the rigidity of the joint cannot be changed, the mechanism is difficult to adapt to different walking environments, and the interactivity is poor.

In chinese patent application No. 201711065264.5, a variable stiffness lower extremity exoskeleton robot is disclosed, which comprises a back plate, a waist flexibility adjustment mechanism, a hip joint mechanism, a thigh, a knee joint mechanism, a shank and an ankle joint mechanism. The variable-stiffness driver is adopted to directly drive the joint, and the driver is arranged at the joint, so that the mass and inertia at the joint are large. The rigidity is changed by changing the fulcrum compression spring, so that the rigidity is easy to change suddenly and is difficult to control.

Disclosure of Invention

The purpose of the invention is as follows: the invention aims to solve the technical problem of the background technology, and provides a variable-rigidity lower limb assistance exoskeleton robot which can be used for actively adjusting the angular rigidity of the movement of a knee joint and improving the flexibility and the safety performance of the exoskeleton knee joint.

The technical scheme is as follows: in order to achieve the purpose, the invention can adopt the following technical scheme:

a variable-rigidity lower limb exoskeleton power-assisted robot comprises a waist mechanism, a hip mechanism and a knee mechanism;

the waist mechanism is connected with a waist wearing piece and comprises a waist frame, a driving motor arranged on the waist frame, a speed reducer matched with the driving motor and a driving disc arranged on the output of the speed reducer, and a driving lasso is wound on the driving disc;

the hip mechanism is connected with a thigh wearing piece and comprises a hip joint steering plate connected with the waist frame, the rear end of the hip joint steering plate is hinged with the waist frame through a hip joint abduction and adduction shaft, and the front end of the hip joint steering plate is bent and extended; the front end of the hip joint steering plate is connected with a hip joint lower plate, the upper end of the hip joint lower plate and a hip joint are hinged with the steering plate through a hip joint bending and extending shaft, and the lower end of the hip joint lower plate extends downwards; a hip joint balance pulley extending outwards is arranged below the hip joint lower plate; the hip mechanism is also provided with a hip joint balance spring and a hip joint lasso which extend up and down, one end of the hip joint lasso extends upwards and is fixedly connected with a hip joint steering plate, the other end of the hip joint lasso extends downwards and is wound around a hip joint balance pulley and then is fixedly connected with the lower end of the hip joint balance spring upwards, and the upper end of the hip joint balance spring is fixedly connected with the upper end of a hip joint lower plate;

the knee mechanism is connected with a shank wearing piece and comprises a knee joint upper plate, a rope tail end stress frame, a knee joint shaft extending outwards from the knee joint upper plate, an input disc arranged on the knee joint shaft, an output disc also arranged on the knee joint shaft and a knee joint lower plate arranged at the lower end of the output disc and extending downwards; the input disc rotates around the knee joint shaft; the output disc is relatively fixed with the knee joint shaft; the outer side of the input disc is provided with a step disc for the driving lasso to pass through, the step disc, the driving disc and the driving lasso form belt transmission, and the driving disc rotates to drive the input disc to rotate through the driving lasso; a plurality of variable-rigidity input pulleys which are uniformly arranged on one surface of the input disc facing the output disc along the same circumference are arranged on the surface of the input disc; the variable stiffness input pulley is axially parallel to the knee joint shaft and surrounds the periphery of the knee joint shaft; a plurality of knee joint output pulleys which are uniformly arranged on one surface of the output disc facing the input disc along the same circumference are arranged on the surface of the output disc, and the knee joint output pulleys are axially parallel to the knee joint shaft and surround the periphery of the knee joint shaft; each variable stiffness input pulley corresponds to each knee joint output pulley one by one, and the variable stiffness input pulleys are positioned on the outer sides of the knee joint output pulleys; the knee mechanism is also provided with a steel wire rope, and the steel wire rope is crossed at the inner side of each knee joint output pulley to form a rope sleeve which is sleeved on the variable-rigidity input pulley; the knee joint lower plate is provided with an auxiliary spring and a tensioning device, the auxiliary spring extends in the same direction along the extension direction of the knee joint lower plate, the upper end of the auxiliary spring is connected with one end of a steel wire rope, and the lower end of the auxiliary spring is connected with a spring fixing device extending out of the outer side of the knee joint lower plate; the other end of the steel wire rope is connected with a tensioning device.

Has the advantages that: the variable-rigidity lower limb exoskeleton power-assisted robot is worn on the lower limbs of a human body, and the driving motor and the driving disc on the waist mechanism are used as driving sources to drive the driving lasso to rotate forwards or backwards so as to drive the input disc of the lower knee mechanism to rotate forwards or backwards, so that the input disc rotates relative to the output disc to drive the knee joint to rotate. In order to overcome the defects that the mechanism is complex, the knee structure has no variable stiffness capability or the variable stiffness effect is poor to cause poor joint motion flexibility in the prior art, a pulley and a steel wire rope are adopted between an input disc and an output disc of the knee mechanism to form a variable stiffness adjusting effect in the scheme. When the input disc rotates relative to the output disc, a deflection angle is generated between the variable-stiffness input pulley and the knee joint output pulley, so that the length of a steel wire rope between the variable-stiffness input pulley and the knee joint output pulley is increased, a spring connected with the steel wire rope is stretched, and then deflection torque is generated between the input disc and the output disc to drive the output disc to rotate to form a series elastic mechanism. Wherein, the spring has a certain stretching amount in the initial state, so that the steel wire rope part connected with the variable stiffness input pulley has a pre-tensioning force for pre-tensioning the knee joint output pulley to form a damping and buffering effect between the pulleys (each group of pulleys is a variable stiffness input pulley and the corresponding knee joint output pulley). The change of the angular stiffness of the joint can be realized by changing the initial stretching amount of the spring, namely changing the pretension force of the steel wire rope between the stiffness-variable input pulley and the knee joint output pulley. When the input disc and the output disc deflect at the same angle under the same initial pretension force, the more the number of the pulley blocks is, the longer the total stretching length of the spring is, the larger the deflection torque is generated, and the joint angle rigidity is increased (the joint angle rigidity is the deflection torque/deflection angle). Therefore, under the condition that the size of the spring is limited, the adjustable range of the angular stiffness of the joint can be determined by adjusting the number of the pulley blocks (the more the number of the pulley blocks is, the larger the range of the angular stiffness adjustment is), so that the angular stiffness adjusting mechanism has better adaptability. . When the variable stiffness mechanism is used for driving, the angular stiffness can be actively changed in the walking process, so that the exoskeleton has the advantages of better flexibility, higher safety and better adaptability. Meanwhile, the rope and the pulley are combined, so that the mechanism is more compact and simpler, and the adaptability is better. Meanwhile, a balance mechanism formed by combining a hip joint lasso, a pulley and a spring is used at the hip joint, so that the overturning moment of the back structure when the user stands is balanced, and a part of assistance can be provided when the user walks.

Furthermore, the waist mechanism, the hip mechanism and the knee mechanism are symmetrical two, and comprise a left waist mechanism, a right waist mechanism, a left hip mechanism, a right hip mechanism, a left knee mechanism and a right knee mechanism; a waist adjusting plate is arranged between the left waist mechanism and the right waist mechanism.

Furthermore, the tensioning device comprises a servo motor arranged on the outer side of the knee joint lower plate and a turbine arranged above the servo motor, wherein an output shaft of the servo motor is provided with a worm matched with the turbine, a turbine connecting shaft extending outwards is further arranged on the outer side of the knee joint lower plate, the turbine is arranged on the turbine connecting shaft, a round table matched with the steel wire rope is arranged on the inner side of the turbine, and the steel wire rope is wound on the round table.

Furthermore, a knee joint rotary encoder and a variable rigidity difference angle rotary encoder are also arranged; the shaft of the left knee joint rotary encoder is connected with a belt wheel at the left encoder; the outer end of the knee joint shaft is connected with a shaft end belt wheel, the belt wheel at the encoder is connected with the shaft end belt wheel through a synchronous belt, and the knee joint rotary encoder is used for measuring the relative angle between the upper knee joint plate and the lower left knee joint plate; the variable stiffness differential angle rotary encoder is used for measuring the relative angle between the input disc and the output disc.

Furthermore, the waist mechanism also comprises a speed reducer bracket and a driving lasso stress frame; the speed reducer bracket is connected to the waist frame through a screw, and a hole and a threaded hole in the speed reducer bracket are used for positioning and connecting the speed reducer; the speed reducer is connected with the internal coupling and the driving motor through screws, and a shaft of the speed reducer is connected with the driving disc through a key; the driving disc is provided with a steel wire rope fixing block, and the steel wire rope fixing block is connected with the driving disc through a screw and used for fixing the driving lasso to transmit power; the driving lasso stress frame is connected with the speed reducer bracket through a screw, and the lasso is pre-tightened through the screw on the side surface; the driving lasso is provided with two upper guide tubes, and two ends of the driving lasso extend from the driving disc and then are respectively guided out from the two upper guide tubes.

Furthermore, the knee mechanism also comprises a lasso tail end stress frame which is fixed on the knee joint upper plate, and two lower guide pipes are arranged at the upper end of the lasso tail end stress frame and used for guiding and fixing the lower end of the driving lasso.

Furthermore, still be equipped with the waist connecting plate that upwards extends on the waist frame, the waist is worn the piece and is installed on this waist connecting plate.

Further, the thigh wearing part is installed on the inner side of the knee joint upper plate.

Furthermore, the hip mechanism is also provided with a hip joint rotary encoder and a hip joint rotary encoder bracket; the hip joint rotary encoder is connected to the hip joint rotary encoder bracket, and the shaft part of the hip joint rotary encoder is adhered to the hip joint flexion and extension shaft and is used for measuring the relative angle between the hip joint lower plate and the hip joint upper plate; the bottom of the hip joint rotary encoder bracket is fixed on the hip joint lower plate.

Further, the lower leg wearing part is arranged on the inner side of the lower plate of the knee joint.

Drawings

FIG. 1 is an isometric view of the unitary construction of the present invention

FIG. 2 is a front view of the overall structure of the present invention

FIG. 3 is a rear view of the overall structure of the present invention

FIG. 4 is an isometric view of a waist feature of the present invention

Figure 5 is an isometric view of a left hip structure of the present invention

FIG. 6 is an isometric view of a right hip structure of the present invention

FIG. 7 is a rear view of the left knee structure of the present invention

FIG. 8 is a rear view of the right knee structure of the present invention

FIG. 9 is a left side perspective view of the variable stiffness knee structure of the present invention

FIG. 10 is an exploded left side view of the variable stiffness knee structure of the present invention.

Wherein each component is named as follows:

a waist structure I, a left hip structure II, a left knee structure III, a right hip structure IV, a right knee structure V, a waist wearing part 1, a left thigh wearing part 2, a left shank wearing part 3, a right thigh wearing part 4, a right shank wearing part 5, a left waist connecting plate 6, an upper conduit 7, a left lasso stress frame 8, a left reducer bracket 9, a left driving disc 10, a left waist bracket 11, a left wire rope fixing block 12, a left reducer 13, a left driving motor 14, a waist adjusting plate 15, a right waist connecting plate 16, a right waist bracket 17, a right lasso stress frame 18, a right reducer bracket 19, a right driving disc 20, a reducer shaft sleeve 21, a reducer end pressing sleeve 22, a right wire rope fixing block 23, a right reducer 24, a right driving motor 25, a left hip joint extension adduction shaft 26, a left hip joint steering plate 27, a left hip joint upper plate 28, a left hip joint lower plate 29, a left joint extension shaft 30, a right joint extension shaft 24, a left hip joint extension shaft and a right joint extension shaft 18, A left hip joint rotary encoder 31, a left hip joint rotary encoder bracket 32, a left hip joint balance spring 33, a left hip joint balance pulley 34, a hip joint balance pulley shaft sleeve 35, a right hip joint steering plate 36, a right hip joint abduction and adduction shaft 37, a right hip joint upper plate 38, a right hip joint rotary encoder 39, a right hip joint rotary encoder bracket 40, a right hip joint balance spring 41, a right hip joint lower plate 42, a right hip joint balance pulley 43, a left knee joint upper plate 44, a left lasso tail end stress frame 45, a left knee joint rotary encoder bracket 46, a left encoder belt wheel 47, a left knee joint rotary encoder 48, a left synchronous belt 49, a left shaft end belt wheel 50, a left variable stiffness difference angle rotary encoder 51, a left variable stiffness difference angle rotary encoder bracket 52, a left knee joint shaft 53, a left input disc cover 54, a left input disc 55, a left limiting block 56, a left knee joint lower plate 57, a left hip joint balance pulley shaft sleeve 40, a right hip joint balance pulley 40, a right hip joint balance spring 41, a right hip joint balance pulley 43, a left knee joint upper plate 44, a left variable stiffness difference angle rotary encoder bracket 52, a left knee joint cover, a left knee joint outer plate, a left knee joint outer cover, a left outer cover, a right sleeve outer cover, a left sleeve outer cover, a right sleeve outer cover, a left sleeve outer cover, a right sleeve outer cover, a left sleeve outer cover, a right sleeve outer cover, a left sleeve outer cover, a right sleeve outer cover, a left sleeve outer cover, a right sleeve outer cover, a left sleeve outer cover, a right sleeve, A left turbine 58, a left output disc 59, a left reel 60, a left turbine connecting shaft 61, a left stiffness-variable servo motor bracket 62, a stiffness-variable control left servo motor 63, a left auxiliary spring 64, a left tension sensor 65, a left joint bearing block 66, a left joint bearing bracket 67, a right knee joint upper plate 68, a right knee joint rotary encoder bracket 69, a right lasso tail end stress bracket 70, a right knee joint output 71, a right encoder pulley 72, a right synchronous belt 73, a right knee joint rotary encoder 74, a right shaft end pulley 75, a right stiffness-variable differential angle rotary encoder 76, a right stiffness-variable differential angle rotary encoder bracket 77, a right input disc cover 78, a right knee joint shaft 79, a right input disc 80, a right limit block 81, a right knee joint output 82, a right knee joint lower plate 83, a right turbine connecting shaft 84, a right stiffness-variable servo motor bracket 85, a right reel 86, a right turbine 87, a stiffness-variable control right servo motor 88, a variable servo motor, A right variable stiffness position spring 89, a right tension sensor 90, a right joint bearing seat 91, a right joint bearing support 92, a knee joint shaft end cover 93, a knee joint output pulley 94, a variable stiffness input pulley 95, a left worm 96, a right worm 97, a steel wire rope 98, a left driving lasso 99, a hip joint steel wire rope 100 and a lower guide pipe 101.

Detailed Description

The detailed description of the embodiments of the present invention is provided in conjunction with the accompanying drawings.

The terms "left" and "right" in the present invention refer to the left and right portions of the structure when worn by a wearer.

As shown in fig. 1 to 3, the invention relates to a variable-rigidity lower limb assistance exoskeleton, which comprises a wearing mechanism, a waist mechanism I, a left hip mechanism II, a left knee mechanism III, a right hip mechanism IV and a right knee mechanism V. Wherein the wearing mechanism comprises a waist wearing piece 1, a left thigh wearing piece 2, a left shank wearing piece 3, a thigh wearing piece right 4 and a right shank wearing piece 5. The waist wearing part 1 is connected to the left waist connecting plate 6 and the right waist connecting plate 16 through screws, the left thigh wearing part 2 is connected to the left knee joint upper plate 44 and the left hip joint lower plate 29 through screws, the left calf wearing part 3 is connected to the left knee joint lower plate 57 through screws, the thigh wearing part right 4 is connected to the right hip joint lower plate 42 and the right knee joint upper plate 68 through screws, and the right calf wearing part 5 is connected to the right knee joint lower plate 83 through screws. The left hip joint lower plate 29 of the left hip mechanism II and the left knee joint upper plate 44 of the left knee mechanism III are connected through screws, and the positions of the left hip joint lower plate and the left knee joint upper plate are adjustable so as to adapt to users with different thigh lengths; the left hip joint lower plate 29 of the right hip mechanism IV and the right knee joint upper plate 68 of the right knee mechanism V are connected through screws, and the positions of the two plates can be adjusted to adapt to users with different thigh lengths.

As shown in fig. 4, which is the lumbar mechanism of the present invention, the left lumbar connecting plate 6 and the right lumbar connecting plate 16 are respectively connected to the left lumbar frame 11 and the right lumbar frame 17 by screws, and their positions can be adjusted to suit different users; the middle parts of the left waist frame 11 and the right waist frame 17 are connected through a waist adjusting plate 15, and the width of the waist can be adjusted by changing the position of the adjusting plate so as to adapt to users with different body types; the left speed reducer bracket 9 is connected to the left waist frame 11 through a screw, and a hole and a threaded hole in the left speed reducer bracket 9 are used for positioning and connecting a left speed reducer 13; the left reducer 13 is connected with the left driving motor 14 through a screw and an internal coupling, and the shaft of the left reducer 13 is connected with the left driving disc 10 through a key; the left steel wire rope fixing block 12 is connected with the left driving disc 10 through a screw and used for fixing the steel wire rope and transmitting power; the left lasso stress frame 8 is connected with the left speed reducer bracket 9 through screws, and the lasso can be pre-tightened through the screws on the side surface; the right waist frame 17, the right lasso stress frame 18, the right reducer bracket 19, the right driving disk 20, the reducer shaft sleeve 21, the reducer end pressing sleeve 22, the right wire rope fixing block 23, the right reducer 24, the right driving motor 25 and corresponding parts on the left have similar assembly relations, which is shown in detail in the figure.

As shown in fig. 5 and 6, is a hip structure of the present invention. Wherein, fig. 5 is a left hip structure, and fig. 6 is a right hip structure. The middle of the left waist frame 11 and the left hip joint abduction and adduction shaft 26 is provided with double bearings which can rotate relatively, the outer ring of the bearing is contacted with the left waist frame 11, the inner ring of the bearing is contacted with the left hip joint abduction and adduction shaft 26, and the bearing is positioned and fixed by the step of the left waist frame 11, the step of the left hip joint abduction and adduction shaft 26, a retaining ring for a shaft and a retaining ring for a hole; the left hip joint steering plate 27 is tightly pressed on the step of the left hip joint abduction and adduction shaft 26 through a round nut, the other side of the left hip joint steering plate 27 is connected with the left hip joint upper plate 28 through a screw, the positions of the left hip joint steering plate and the left hip joint upper plate are adjustable, and the applicability is improved; the other end of the left hip joint upper plate 28 is tightly pressed on the step of the left hip joint flexion-extension shaft 30 through a round nut; a bearing is arranged between the left hip joint lower plate 29 and the left hip joint flexion and extension shaft 30 and can rotate relatively, the outer ring of the bearing is in contact with the left hip joint lower plate 29, the inner ring of the bearing is in contact with the left hip joint flexion and extension shaft 30, and the bearing is positioned and fixed through the step of the left hip joint lower plate 29, the step of the left hip joint flexion and extension shaft 30, a shaft check ring and a hole check ring; the left hip joint rotary encoder 31 is connected to a left hip joint rotary encoder bracket 32 through screws, the shaft part is adhered to the left hip joint flexion-extension shaft 30 and used for measuring the relative angle between the left hip joint lower plate 29 and the left hip joint upper plate 28, and the bottom of the left hip joint rotary encoder bracket 32 is fixed on the left hip joint lower plate 29 through screws; one end of the left hip joint balance spring 33 is hooked on a screw connected on the left hip joint lower plate 29, one end is connected with the hip joint steel wire rope 100, and the hip joint steel wire rope 100 extends until the other end of the hip joint steel wire rope 100 is fixed on the left hip joint upper plate 28 through the guidance of the left hip joint balance pulley 34. When the user is at rest, the tension force provided by the hip joint steel wire rope 100 to the left hip joint balance spring 33 is combined with the elastic force of the left hip joint balance spring 33 to balance the overturning moment of the waist mechanism caused by gravity, so that the comfort is improved, and the assistance can be provided during the walking process. The right and left hip structures are similar in their relationship to each other and function, as shown in detail in figure 5.

As shown in fig. 7, 8 and 9, the knee structure of the present invention is shown. Fig. 7 is a left knee structure, fig. 7 is a right knee structure, and fig. 9 is a variable stiffness mechanism. The left knee joint shaft 53 is connected with a left input disc 55, a left output disc 59, a left knee joint upper plate 44 and a left shaft end belt wheel 50. Wherein, a double bearing is arranged between the left input disk 55 and the left knee joint shaft 53 to rotate relatively, the outer ring of the bearing is contacted with the left input disk 55 and is positioned and fixed by the step of the left input disk 55 and the left input disk cover 54, the inner ring of the bearing is contacted with the left knee joint shaft 53 and is positioned and fixed by the step of the left knee joint shaft 53 and the retaining ring for the shaft; the left output disc 59 is connected with the left knee joint shaft 53 through a key and cannot rotate relatively; a double bearing is arranged between the left knee joint upper plate 44 and the left knee joint shaft 53 and can rotate relatively, the outer ring of the bearing is contacted with the left knee joint upper plate 44 and is positioned and fixed through the step of the left knee joint upper plate 44 and the knee joint shaft end cover 93, the inner ring of the bearing is contacted with the left knee joint shaft 53 and is positioned and fixed through the step of the left knee joint shaft 53 and the shaft check ring; the left shaft end belt wheel 50 is connected with a left knee joint shaft 53 through a set screw; the bottom of the left lasso tail end stress frame 45 is fixed on the left knee joint upper plate 44 through screws, two holes at the upper end are used for fixing the upper guide pipe 7, and a steel wire rope 98 guided by the upper guide pipe 7 winds the outer ring of the left input disc 55 to transmit the torque of the far-end left driving motor 14, so that the torque input of the joint is realized. Two downcomers 101 are provided at the upper end of the left lasso end stress frame 45 for guiding and securing the lower end of the left drive lasso 99. The left input disc 55 is provided on its outer side with a left step disc around which the lasso is driven. The left input disc 55 is provided with a plurality of variable stiffness input pulleys 95 (in this embodiment, six variable stiffness input pulleys 95 are included) on a surface facing the left output disc 59, the input pulleys being arranged uniformly along the same circumference. The variable stiffness input pulley 95 is axially parallel to the left knee joint axis 53 and surrounds the left knee joint axis 53. The left output disc 59 is provided with a plurality of left knee joint output pulleys 94 on one surface facing the left input disc 55, the left knee joint output pulleys 94 are uniformly arranged along the same circumference on the surface, and the left knee joint output pulleys 94 are parallel to the knee joint shaft 53 and surround the periphery of the knee joint shaft 53. And each left variable stiffness input pulley 95 corresponds one-to-one to each left knee joint output pulley 94, and the left variable stiffness input pulley 95 is located outside the left knee joint output pulley 94. The left knee mechanism is further provided with a wire rope 98, and the wire rope 98 is crossed at the inner side of each left knee joint output pulley 95 to form a rope loop and is sleeved on the variable stiffness input pulley 95. The left knee joint lower plate 57 is provided with a left auxiliary spring 64 and a left tensioning device. The tensioning device comprises a left servo motor 63 arranged on the outer side of the lower plate of the left knee joint and a left turbine 58 arranged above the left servo motor 63.

The two knee joint output pulleys 94 on the left output disc 59 can avoid extra friction caused by mutual winding of the steel wire rope 98, one end of the steel wire rope 98 is connected with the left auxiliary spring 64, the other end of the steel wire rope 98 is connected with the left reel 60, the change of the rigidity of the joint can be realized by changing the pretightening force of the left auxiliary spring 64, the rigidity range of the joint can be increased or decreased by increasing or decreasing the number of pulley sets between the left input disc 55 and the left output disc 59, and the rigidity characteristic of the joint can be changed; the bottom of the left variable stiffness servo motor support 62 is connected with the left knee joint lower plate 57 through a screw, the upper part of the left variable stiffness servo motor support 62 is connected with the variable stiffness control left servo motor 63 through a screw, the variable stiffness control left servo motor 63 is connected with the left worm 96 through a set screw on the shaft, the left worm 96 is in contact with the left turbine 58 to transmit power, and the left variable stiffness servo motor support 62 drives the worm to change the pretightening force of the left auxiliary spring 64, so that the stiffness change of the knee joint is realized. The left turbine 58 is connected with a left turbine connecting shaft 61 through a set screw, a key is arranged on the left turbine connecting shaft 61 and is connected with a left reel 60, double bearings are arranged between the left turbine connecting shaft 61 and the left knee joint lower plate 57, the outer ring of the bearing is positioned and fixed through a step and a hole of the left knee joint lower plate 57 by a retainer ring, and the inner ring of the bearing is fixed through the step of the left turbine connecting shaft 61 and a shaft retainer ring; one end of a left tension sensor 65 is connected with the left auxiliary spring 64, and the other end is connected with the left joint bearing block 66, and is used for measuring the tension of the left auxiliary spring 64 and estimating the torque of the knee joint; the left joint bearing block 66 is fixed on the left joint bearing bracket 67 through a screw, and the bottom of the left joint bearing bracket 67 is fixed on the left knee joint lower plate 57 through a screw; the left knee joint lower plate 57 is connected with a left output disc 59 through screws; the bottom of the left knee joint rotary encoder bracket 46 is connected with the left knee joint upper plate 44 through screws, the upper part of the left knee joint rotary encoder bracket is connected with a left knee joint rotary encoder 48, a shaft of the left knee joint rotary encoder 48 is connected with a left encoder belt wheel 47 through a set screw, the left encoder belt wheel 47 is connected with a left shaft end belt wheel 50 through a left synchronous belt 49, and therefore the left knee joint rotary encoder 48 can measure the relative angle between the left knee joint upper plate 44 and the left knee joint lower plate 57; the bottom of the left variable stiffness differential angle rotary encoder bracket 52 is connected to a left input disc 55 through a screw, the upper part of the left variable stiffness differential angle rotary encoder bracket 52 is connected with a left variable stiffness differential angle rotary encoder 51, and the shaft of the left variable stiffness differential angle rotary encoder 51 is adhered to a left knee joint shaft 53 and used for measuring the relative angle between the left input disc 55 and the left output disc 59 and estimating the angular stiffness of the knee joint. The assembled relationship of the right knee structure and the assembled relationship of the left knee structure are identical, see in particular fig. 8.

Various other modifications and changes may be made by those skilled in the art based on the above-described technical solutions and concepts, and all such modifications and changes should fall within the scope of the claims of the present invention.

Claims

1. The utility model provides a variable rigidity lower limbs ectoskeleton helping hand robot which characterized in that: comprises a waist mechanism, a hip mechanism and a knee mechanism;

the hip mechanism is connected with a thigh wearing piece and comprises a hip joint steering plate connected with the waist frame, the rear end of the hip joint steering plate is hinged with the waist frame through a hip joint abduction and adduction shaft, and the front end of the hip joint steering plate is bent and extended; the front end of the hip joint steering plate is connected with a hip joint lower plate, the upper end of the hip joint lower plate and the hip joint upper plate are hinged with the steering plate through a hip joint bending and extending shaft, and the lower end of the hip joint lower plate extends downwards; a hip joint balance pulley extending outwards is arranged below the hip joint lower plate; the hip mechanism is also provided with a hip joint balance spring and a hip joint lasso which extend up and down, one end of the hip joint lasso extends upwards and is fixedly connected with the upper hip joint plate, the other end of the hip joint lasso extends downwards and is wound around the hip joint balance pulley and then is fixedly connected with the lower end of the hip joint balance spring upwards, and the upper end of the hip joint balance spring is fixedly connected with the upper end of the lower hip joint plate;

2. The variable stiffness lower extremity exoskeleton assistance robot of claim 1, wherein: the waist mechanism, the hip mechanism and the knee mechanism are symmetrical and comprise a left waist mechanism, a right waist mechanism, a left hip mechanism, a right hip mechanism, a left knee mechanism and a right knee mechanism; the left waist mechanism and the right waist mechanism are connected through a waist adjusting plate.

3. The variable stiffness lower extremity exoskeleton assistance robot of claim 1 or 2, wherein: the tensioning device comprises a servo motor arranged on the outer side of the knee joint lower plate and a turbine arranged above the servo motor, wherein an output shaft of the servo motor is provided with a worm matched with the turbine, a turbine connecting shaft extending outwards is further arranged on the outer side of the knee joint lower plate, the turbine is arranged on the turbine connecting shaft, a round platform matched with a steel wire rope is arranged on the inner side of the turbine, and the steel wire rope is wound on the round platform.

4. The variable stiffness lower extremity exoskeleton assistance robot of claim 3, wherein: a knee joint rotary encoder and a variable rigidity difference angle rotary encoder are also arranged; the shaft of the knee joint rotary encoder is connected with a belt wheel at the encoder; the outer end of the knee joint shaft is connected with a shaft end belt wheel, the belt wheel at the encoder is connected with the shaft end belt wheel through a synchronous belt, and the knee joint rotary encoder is used for measuring the relative angle between the knee joint upper plate and the knee joint lower plate; the variable stiffness differential angle rotary encoder has a shaft connected to the knee joint shaft, and is used to measure the relative angle between the input disc and the output disc.

5. The variable stiffness lower extremity exoskeleton assistance robot of claim 4, wherein: the waist mechanism also comprises a speed reducer bracket and a driving lasso stress frame; the speed reducer bracket is connected to the waist frame through a screw, and a hole and a threaded hole in the speed reducer bracket are used for positioning and connecting the speed reducer; the speed reducer is connected with the internal coupling and the driving motor through screws, and a shaft of the speed reducer is connected with the driving disc through a key; the driving disc is provided with a steel wire rope fixing block, and the steel wire rope fixing block is connected with the driving disc through a screw and used for fixing the driving lasso to transmit power; the driving lasso stress frame is connected with the speed reducer bracket through a screw, and the lasso is pre-tightened through the screw on the side surface; the driving lasso is provided with two upper guide tubes, and two ends of the driving lasso extend from the driving disc and then are respectively guided out from the two upper guide tubes.

6. The variable stiffness lower extremity exoskeleton assistance robot of claim 5, wherein: the knee mechanism also comprises a lasso tail end stress frame which is fixed on the knee joint upper plate, and two lower guide pipes are arranged at the upper end of the lasso tail end stress frame and used for guiding and fixing the lower end of the driving lasso.

7. The variable stiffness lower extremity exoskeleton assistance robot of claim 5, wherein: still be equipped with the waist connecting plate that upwards extends on the waist frame, the waist is worn the piece and is installed on this waist connecting plate.

8. The variable stiffness lower extremity exoskeleton assistance robot of claim 6, wherein: the thigh wearing part is arranged on the inner side of the upper plate of the knee joint.

9. The variable stiffness lower extremity exoskeleton assistance robot of claim 6, wherein: the hip mechanism is also provided with a hip joint rotary encoder and a hip joint rotary encoder bracket; the hip joint rotary encoder is connected to the hip joint rotary encoder bracket, and the shaft part of the hip joint rotary encoder is connected with the hip joint flexion-extension shaft and is used for measuring the relative angle of the hip joint lower plate and the hip joint upper plate; the bottom of the hip joint rotary encoder bracket is fixed on the hip joint lower plate.

10. The variable stiffness lower extremity exoskeleton assistance robot of claim 9, wherein: the lower leg wearing part is arranged on the inner side of the lower plate of the knee joint.