CN114825762B - A knee joint exoskeleton for generating electricity based on negative work recovery and a method for generating electricity thereof - Google Patents

Abstract

The invention discloses a knee joint exoskeleton capable of generating power based on negative power recovery and a power generation method thereof. The invention collects the negative work generated by the knee joint when the human body walks, realizes that the human can acquire electric energy at any time when walking, can ensure the unidirectional rotation of the generator when collecting the electric energy, not only prolongs the service life of the generator, but also avoids the influence of the impact of the generator on the gait when walking normally; in addition, the artificial thigh support and the artificial shank support are integrally designed by adopting a curved surface, and the conventional rod-shaped design is abandoned, so that the leg support is more fit with the surface of a human body, and the design is fit with the curve of the human body, so that the artificial thigh support is more comfortable to wear.

Description

A knee joint exoskeleton for generating electricity based on negative work recovery and a method for generating electricity thereof

Technical Field

The present invention relates to the technical field of exoskeleton robots, and in particular to a knee joint exoskeleton for generating electricity based on negative work recovery and a method for generating electricity thereof.

Background technique

In recent years, we have become increasingly dependent on portable electronic devices. These devices range from biomedical devices, such as pacemakers and electromechanical prostheses, to consumer products, such as mobile phones, personal digital assistants, and global positioning systems. Currently, all of these devices are powered by batteries, which increases weight, size, and inconvenience for users, and there is a need to develop alternative sustainable energy sources.

Therefore, researchers are exploring sustainable energy supplies for portable devices to solve these problems. Human muscles are the source of mechanical power required to obtain biomechanical energy, and muscles require metabolic energy to complete positive and negative work. Harvesters based on obtaining energy from human movement are gradually used to power portable devices. When the human body walks normally, the knee joint generates about 67W of power to assist walking, of which about 90% of the power performs negative work. By harvesting the power generated by the human body when walking, the generated electricity can fully meet the power needs of portable devices.

At present, there are mainly two types of devices for realizing human power generation at home and abroad. One is to collect joint movement in both directions, that is, to collect the positive and negative work of the human body at the same time; the other is to selectively recover only the negative work of a certain gait stage. The most common is to recover the negative work generated when the knee flexor acts on the brake leg movement at the end of the swing stage. When the first device is performing bidirectional collection, the generator needs to continuously rotate forward and reverse. The inertia of the generator rotor can easily impact the human body and affect the gait during normal walking; the second device only recovers part of the negative work, and there is still room for improvement in efficiency and power generation. Therefore, it is necessary to study a new type of human power generation device that can collect all the negative work generated by the human knee joint when the human body is walking normally, and will not cause the motor to rotate forward and reverse.

Summary of the invention

The technical problem to be solved by the present invention is to provide a knee joint exoskeleton that generates electricity based on negative work recovery. By setting two groups of leg support transmission devices with opposite rotation outputs and cooperating with two groups of reversing transmission components with opposite transmission directions, negative work can be achieved in different gait stages of the knee joint. The collection of negative work is more sufficient and efficient, and the generator is driven to rotate in the same direction to achieve continuous power generation, avoiding continuous forward and reverse rotation of the generator during the process of collecting energy. While increasing the service life of the generator, it also avoids the impact of the generator on the normal gait during walking.

In order to solve the above technical problems, a technical solution adopted by the present invention is: to provide a knee joint exoskeleton for generating electricity based on negative work recovery, comprising an anthropomorphic thigh support and an anthropomorphic calf support, both sides of the calf support are connected to a leg support transmission device, the power output end of the leg support transmission device is connected to a reversing transmission assembly, and the power output end of the reversing transmission assembly is connected to a power generation mechanism;

The leg support transmission device includes a rack fixedly connected to one side of the calf support, a transmission gear A meshing with the rack and rotatably mounted on the side wall of the thigh support, a transmission gear B coaxially arranged with the transmission gear A, a gear rotating disk meshing with the transmission gear B, a ratchet pawl rotatably connected to the end of the gear rotating disk, and a ratchet disk coaxially sleeved with the ratchet pawl for transmission, and the two ratchet disks located on both sides of the thigh support have opposite driving directions;

The reversing transmission assembly includes a side plate connecting rod fixedly connected to one side of the middle part of the thigh support, side plates fixed to both ends of the side plate connecting rod and symmetrically arranged, a side plate gear coaxially arranged with the gear rotating disk, and a transmission gear meshingly connected with the side plate gear in sequence, the side plate gear and the transmission gear are both rotatably mounted on the side wall of the side plate, and the number of the transmission gears rotatably mounted on the two side plates is one odd and one even;

The power generation mechanism includes a generator fixedly mounted on the side plate connecting rod, a ratchet fixedly mounted on the generator input shaft, and a left gear shaft and a right gear shaft respectively rotatably mounted on the side plate connecting rod. The opposite ends of the left gear shaft and the right gear shaft are fixedly provided with spring pawl plates, and the end surface of each spring pawl plate is provided with a plurality of small pawls evenly distributed and cooperating with the ratchet for transmission.

Furthermore, a leg bracket drive shaft is rotatably mounted on the inner wall of the thigh bracket via a bearing, the end of the calf bracket and the end of the rack are fixed to the leg bracket drive shaft via a key connection, the gear turntable is rotatably mounted on the middle part of the leg bracket drive shaft via a bearing, and the ratchet plate is rotatably mounted on the end of the leg bracket drive shaft away from the thigh bracket via a bearing.

Furthermore, the rack is a quarter-arc-shaped internal gear structure, and its central axis coincides with the axis of the leg support transmission shaft.

Furthermore, a thigh support extension section is integrally provided at the bottom of the thigh support, and the transmission gear A is rotatably mounted on the thigh support extension section and is located on one side of the leg support transmission shaft.

Furthermore, an upper fixing frame is fixedly provided on the middle front side of the thigh support, and a thigh strap is connected to the rear side of the end of the upper fixing frame. A lower fixing frame is fixedly provided on the middle front side of the calf support, and a calf strap is connected to the rear side of the end of the lower fixing frame.

Furthermore, a motor tripod and bearing seats on both sides of the motor tripod are fixedly arranged above the middle part of the side plate connecting rod, a reducer is fixedly connected to the input shaft end of the generator, the reducer is fixedly mounted on the motor tripod, and the left gear shaft and the right gear shaft are rotatably mounted on two bearing seats through bearings respectively.

Furthermore, the two ends of the side panel connecting rod are fixedly connected to the middle parts of both sides of the thigh support through the inclined thigh support connecting rod.

Furthermore, two transmission gears are rotatably mounted on the side plate on one side, and three transmission gears are rotatably mounted on the side plate on the other side.

A method for generating electricity for the knee joint exoskeleton is also provided, comprising the following main steps:

S10, putting the thigh support on the thigh of the user, and putting the calf support on the calf of the user, and fixing them by tying with the thigh strap and the calf strap;

S20, the user walks on flat ground with a normal walking gait. In the swinging stage of walking on one side of the calf, the calf support rotates unidirectionally relative to the thigh support. The leg support transmission device located on one side of the thigh support transmits the relative rotation to the power generation mechanism through the reversing transmission component on the corresponding side, thereby driving the generator of the power generation mechanism to rotate unidirectionally by a certain angle to generate electrical energy;

S30, in the standing stage of walking at the same calf part, the calf support rotates in a unidirectional reverse direction relative to the thigh support, and the leg support transmission device located on the other side of the thigh support transmits the relative rotation to the power generation mechanism through the reversing transmission component on the corresponding side, thereby driving the generator of the power generation mechanism to rotate unidirectionally in the same direction by a certain angle to generate electrical energy;

S40, the lower leg on the other side performs steps S20 and S30 to complete the same power generation process;

S50, repeating steps S20 to S40 to achieve alternating power generation by the legs on both sides;

S60: After power generation is completed, loosen the thigh straps and calf straps, and take off the knee exoskeleton.

The beneficial effects of the present invention are as follows:

1. The present invention adopts two symmetrically arranged input mechanisms, each of which is designed with a one-way transmission mechanism. When a person walks normally, the power generation device can effectively collect the negative work generated by the knee joint in each gait stage, reduce the loss of human metabolic energy, and convert the human body's bioenergy into the electrical energy of the generator, so that a person can obtain electrical energy anytime and anywhere when walking normally, so as to provide normal use of portable devices;

2. The present invention provides a leg support transmission device with opposite output directions, and provides a reversing transmission assembly with different numbers of gears on the left and right side panels, so that the two input mechanisms finally input the same rotation direction to the ratchet, thereby avoiding the continuous forward and reverse rotation of the generator during energy collection, and increasing the service life of the generator while also avoiding the impact of the generator on the normal walking gait;

3. The present invention adopts anthropomorphic thigh supports and calf supports, and adopts a curved surface design as a whole, abandoning the conventional rod-shaped design, so that the leg supports are more close to the human body surface and the design conforms to the human body curve, so it will be more comfortable to wear.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a three-dimensional structural diagram of a knee joint exoskeleton of the present invention;

FIG2 is a three-dimensional structural diagram of the power generation mechanism of the knee joint exoskeleton of the present invention;

FIG3 is a three-dimensional structural diagram of the side plate and the connecting rod part of the knee joint exoskeleton of the present invention;

FIG4 is a three-dimensional structural diagram of a leg support transmission device of a knee joint exoskeleton of the present invention;

FIG5 is a top view of the structure of the leg support transmission device of the knee joint exoskeleton of the present invention;

FIG6 is a cross-sectional structural diagram of a leg support transmission device of a knee joint exoskeleton of the present invention;

FIG. 7 is a flow chart of the method for generating electricity for the knee joint exoskeleton of the present invention.

In the figure: 1 thigh support, 2 thigh strap, 3 ratchet plate, 4 side plate bearing end cover, 5 side plate, 6 side plate connecting rod, 7 calf strap, 8 calf support, 9 motor, 10 reducer, 11 spring ratchet plate, 12 motor tripod, 13 internal thread cylindrical pin, 14 ratchet, 15 bearing seat, 16 side plate gear, 17 gear turntable, 18 pawl, 19 thigh support connecting rod, 20 right gear shaft, 21 small pawl, 22 left gear shaft, 23 side plate gear shaft, 24 rack, 25 transmission gear B, 26 transmission gear A, 27 thigh support extension section bearing end cover, 28 thigh support bearing end cover, 29 thigh support extension section short shaft.

Detailed ways

The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

Please refer to Figures 1 to 6, a knee joint exoskeleton for generating electricity based on negative work recovery, including an anthropomorphic thigh support 1 and an anthropomorphic calf support 8. The anthropomorphic thigh support 1 and the calf support 8 are designed with a curved surface as a whole, abandoning the conventional rod-shaped design, so that the leg support is more in line with the human body surface, and the design is ergonomic, so it is more comfortable to wear. The inner wall of the thigh support 1 is rotatably mounted with a leg support transmission shaft through a bearing, and the end of the calf support 8 is fixed to the leg support transmission shaft through a key connection, so that the calf support 8 can rotate relative to the thigh support 1. The outer wall of the thigh support 1 is connected with a thigh support bearing end cover 28 located on the outside of the end bearing of the leg support transmission shaft by bolts. The middle front side of the thigh support 1 is integrally formed and fixed with a U-shaped upper fixing frame, and the rear side of the end of the upper fixing frame is connected with a thigh strap 2, and the middle front side of the calf support 8 is integrally formed and fixed with a U-shaped lower fixing frame, and the rear side of the end of the lower fixing frame is connected with a calf strap 7. Both the thigh strap 2 and the calf strap 7 are elastic straps. When the knee joint exoskeleton is in use, the thigh support 1 and the upper fixing frame are buckled on the thigh, and the calf support 8 and the lower fixing frame are buckled on the calf, and then they are tied and tightened by the thigh strap 2 and the calf strap 7 respectively. The movement of the knee joint can drive the calf support 8 to move relative to the thigh support 1.

Both sides of the calf support 8 are connected with a leg support transmission device. As shown in Figures 4 to 6, the leg support transmission device includes a rack 24 fixedly connected to one side of the calf support 8, a transmission gear A26 meshing with the rack 24 and rotatably mounted on the side wall of the thigh support 1, a transmission gear B25 coaxially arranged with the transmission gear A26, a gear rotating disk 17 meshing with the transmission gear B25, a ratchet 18 rotatably connected to the end of the gear rotating disk 17, and a ratchet disc 3 coaxially sleeved with the ratchet 18 and movably sleeved with the gear rotating disk 17.

The rack 24 is a quarter-circular arc-shaped internal gear structure, and its central axis coincides with the axis of the leg support transmission shaft. The ends of the rack 24 are fixed to the leg support transmission shaft through key connection and are located on the inner side of the calf support 8. When the calf support 8 rotates relative to the thigh support 1, it will drive the transmission shaft between the legs to rotate, and then drive the rack 24 to rotate synchronously. The bottom of the thigh support 1 is integrally provided with a thigh support extension section, and the thigh support extension section is rotatably mounted with a thigh support extension section short shaft 29 on the side wall where the rack 24 is located through a bearing. The transmission gear A26 and the transmission gear B25 are fixedly sleeved on the thigh support extension section short shaft 29 by key connection, and the transmission gear A26 is meshed with the rack 24. The outer wall of the thigh support extension section is fixedly provided with a thigh support extension section bearing end cover 27 located on the outer side of the shaft end bearing of the thigh support extension section short shaft 29 by bolt connection. When the rack 24 rotates around the leg support transmission shaft, the transmission gear A26 can be driven to rotate through the meshing transmission action, and the transmission gear B25 rotates synchronously with the transmission gear A26.

The gear turntable 17 is an integrated structure consisting of a gear and a turntable, and is rotatably sleeved on the middle part of the leg support transmission shaft through a bearing. Among them, the gear part is meshed and connected with the transmission gear B25 to realize meshing transmission, thereby driving the rotation of the turntable. The turntable is a shuttle-shaped structure, and ratchets 18 are rotatably installed on the side surfaces at both ends. The ratchet plate 3 is rotatably sleeved on the end of the leg support transmission shaft away from the thigh support 1 through a bearing, and the ratchet 18 is kept in cooperation with the tooth groove in the ratchet plate 3 by a spring arranged on the side of the turntable, thereby forming a ratchet transmission mechanism. After the gear turntable 17 is driven by the transmission gear B25, the ratchet plate 3 is driven to rotate through the ratchet 18.

In the present knee joint exoskeleton, the leg support transmission devices located on both sides of the thigh support 1 are symmetrically arranged, but the driving directions of the two ratchet discs 3 are opposite. Therefore, when the calf support 8 rotates in the positive direction (clockwise from the perspective shown in FIG. 4) relative to the thigh support 1, the ratchet disc 3 on one side (the right side from the perspective shown in FIG. 1) rotates counterclockwise under the action of the ratchet 18, while the ratchet disc 3 on the other side (the left side from the perspective shown in FIG. 1) is not affected by the ratchet 18 on the corresponding side and remains stationary; on the contrary, when the calf support 8 rotates in the reverse direction (counterclockwise from the perspective shown in FIG. 4) relative to the thigh support 1, the ratchet disc 3 on the left side rotates clockwise under the action of the ratchet 18, while the ratchet disc 3 on the right side is not affected by the ratchet 18 on the corresponding side and remains stationary. By using two sets of leg support transmission devices with opposite output directions, the collection of negative work can be achieved in two different gait stages of walking in the calf area, namely the swinging stage and the standing stage.

The power output end of the leg support transmission device is connected to a reversing transmission assembly. As shown in FIG1 , the reversing transmission assembly includes a side panel connecting rod 6 fixedly connected to one side of the middle part of the thigh support 1, a side panel 5 fixed to both ends of the side panel connecting rod 6 and symmetrically arranged, a side panel gear 16 coaxially arranged with the gear turntable 17, and a transmission gear meshed with the side panel gear 16 in sequence. As shown in FIG3 , both ends of the side panel connecting rod 6 are fixedly provided with a thigh support connecting rod 19, the thigh support connecting rod 19 is tilted, and its bottom end is integrally formed and fixedly provided on the side panel connecting rod 6, and the top end is fixedly provided in the middle of both sides of the thigh support 1 by bolt connection. The two side panels 5 are symmetrically integrally formed and fixedly provided at both ends of the side panel connecting rod 6, and then the thigh support 1, the calf support 8, the side panel connecting rod 6 and the two side panels 5 are assembled and connected to form the frame part of the entire device.

The side plate gear 16 and the transmission gear are both rotatably mounted on the side wall of the side plate 5. As shown in FIG6 , the side plate gear 16 is sleeved with a rotating shaft and connected to the rotating shaft by a key. The inner end of the rotating shaft is fixedly connected to the end face of the ratchet disc 3, and the outer end is rotatably mounted in the side wall of the side plate 5 through a bearing. The outer wall of the side plate 5 is fixedly provided with a side plate bearing end cover 4 located outside the bearing at the end of the rotating shaft by bolt connection. The number of transmission gears rotatably mounted on the two side plates 5 is one odd and one even. In this embodiment, two gear mounting shafts are fixedly provided on the side plate 5 on one side, and a transmission gear is rotatably sleeved on each gear mounting shaft. Three gear mounting shafts are fixedly provided on the side plate 5 on the other side, and a transmission gear is rotatably mounted on each gear mounting shaft. Since the transmission gears mesh in sequence to transmit, the rotation of the side plate gear 16 is changed and then output, so the position distribution of each transmission gear on the side plate 5 only needs to meet the meshing transmission relationship. Since the rotation directions transmitted to the side plate gears 16 by the ratchet disks 3 on both sides are opposite, and the number of transmission gears on both sides is an odd number and an even number, the direction of rotation of the transmission gears at the end of the transmission chain on the side plates 5 on both sides is the same, that is, in the two different gait stages of the swinging stage and the standing stage of the calf walking, a single-direction power output can be achieved through the reversing transmission assembly, and since the leg support transmission device adopts a ratchet structure to achieve unidirectional power output, the power output on both sides is continuously alternated.

The power output end of the reversing transmission assembly is connected to a power generation mechanism. As shown in FIG2 , the power generation mechanism includes a generator 9 fixedly mounted on the side plate connecting rod 6, a ratchet 14 fixedly mounted on the input shaft of the generator 9, and a left gear shaft 22 and a right gear shaft 20 respectively rotatably mounted on the side plate connecting rod 6. The opposite ends of the left gear shaft 22 and the right gear shaft 20 are fixedly provided with spring ratchet discs 11, and the end surface of each spring ratchet disc 11 is provided with a plurality of small ratchets 21 evenly distributed and cooperating with the ratchet 14 for transmission. The ratchet 14 is sleeved on the input shaft of the generator 9 and is positioned and fastened with a locking screw by an internal threaded cylindrical pin 13. The two spring ratchet discs 11 are fixed on the left gear shaft 22 and the right gear shaft 20 by a key connection, and the reset of each small ratchet 21 is achieved by a spring. In this embodiment, six small ratchets 21 are evenly distributed on the end surface of each spring ratchet disc 11 around the circumference of its axis, and the directions of all the small ratchets 21 on the two spring ratchet discs 11 are consistent. The shaft ends of the left gear shaft 22 and the right gear shaft 20 are coaxially fixed with the power output ends of the reversing transmission components on both sides, that is, the transmission gear at the end of the transmission chain. Since the power output directions on both sides are consistent, the rotation directions of the left gear shaft 22 and the right gear shaft 20 are also the same, so that the ratchet wheel 14 can be alternately driven to rotate in a single direction through the small pawl 21, thereby driving the generator 9 to rotate continuously in a single direction to generate electricity, avoiding the continuous forward and reverse rotation of the generator 9 during the process of collecting energy, and increasing the service life of the generator 9 while also avoiding the impact of the generator 9 on the normal walking gait.

Since the gear shaft is slightly slender, in order to reduce vibration and make the transmission more precise, as shown in Figure 3, a motor tripod 12 and a bearing seat 15 located on both sides of the motor tripod 12 and fixed to the side plate connecting rod 6 by bolts are integrally formed and fixed on the upper middle part of the side plate connecting rod 6, the input shaft end of the generator 9 is fixedly connected to the reducer 10 by bolts, and the reducer 10 is fixedly installed on the motor tripod 12 by bolts, and the left gear shaft 22 and the right gear shaft 20 are rotatably installed on the two bearing seats 15 through bearings respectively.

The gait cycle of a normal person walking is divided into a swing phase and a stance phase. According to relevant data, negative work mainly occurs at the end of the swing phase and the beginning and end of the stance phase. The following uses the knee joint exoskeleton shown in Figure 1 as an example of using it on the right leg to illustrate its specific usage.

Please refer to FIG. 7 , a power generation method applied to the knee joint exoskeleton includes the following main steps:

S10, the thigh support 1 is mounted on the thigh of the user, and the calf support 8 is mounted on the calf of the user, and fixed by the thigh strap 2 and the calf strap 7;

S20, the user walks on flat ground with a normal walking gait. In the swinging phase of the right leg calf, negative work mainly occurs in the unidirectional (clockwise from the perspective shown in FIG1 ) movement phase of the calf support 8 relative to the thigh support 1. The leg support transmission device located on the right side of the thigh support 1 transmits the relative rotation to the power generation mechanism through the reversing transmission component on the corresponding side, thereby driving the generator of the power generation mechanism to rotate unidirectionally by a certain angle to generate electrical energy, completing the conversion of mechanical energy into electrical energy;

S30, in the standing stage of walking at the right leg calf part, negative work mainly occurs in the unidirectional reverse (counterclockwise from the perspective shown in FIG1 ) movement stage of the calf support 8 relative to the thigh support 1, and the leg support transmission device located on the left side of the thigh support 1 transmits the relative rotation to the power generation mechanism through the reversing transmission component on the corresponding side, thereby driving the generator of the power generation mechanism to rotate unidirectionally in the same direction by a certain angle to generate electrical energy, completing the conversion of mechanical energy into electrical energy;

S40, the calf part of the left leg performs steps S20 and S30 in the same manner as the right leg, completing the same power generation process;

S50, when the left leg and the right leg continuously and alternately move, steps S20 to S40 are repeatedly executed to realize continuous alternating power generation by the legs on both sides, and the power generation mechanism continuously outputs stable electric energy;

S60, power generation is completed, the thigh strap 2 and the calf strap 7 are loosened, and the knee joint exoskeleton is taken off.

The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims (9)

1. Knee joint exoskeleton capable of generating power based on negative power recovery, and is characterized in that: the leg support comprises a humanoid thigh support (1) and a humanoid shank support (8), wherein both sides of the shank support (8) are connected with leg support transmission devices, the power output end of each leg support transmission device is connected with a reversing transmission assembly, and the power output end of each reversing transmission assembly is connected with a power generation mechanism;

The leg support transmission device comprises a rack (24) fixedly connected to one side of a lower leg support (8), a transmission gear A (26) meshed with the rack (24) and rotatably installed on the side wall of the thigh support (1), a transmission gear B (25) coaxially arranged with the transmission gear A (26), a gear turntable (17) meshed with the transmission gear B (25), a pawl (18) rotatably connected to the tail end of the gear turntable (17), ratchet plates (3) matched with the pawl (18) for transmission and coaxially and movably sleeved with the gear turntable (17), and the driving directions of the two ratchet plates (3) positioned on two sides of the thigh support (1) are opposite;

The reversing transmission assembly comprises a side plate connecting rod (6) fixedly connected to one side of the middle of the thigh support (1), side plates (5) fixed at two ends of the side plate connecting rod (6) and symmetrically arranged, side plate gears (16) coaxially arranged with the gear turntables (17) and transmission gears sequentially meshed with the side plate gears (16), wherein the side plate gears (16) and the transmission gears are rotatably arranged on the side walls of the side plates (5), and the number of the transmission gears rotatably arranged on the two side plates (5) is one odd pair;

the power generation mechanism comprises a power generator (9) fixedly mounted on a side plate connecting rod (6), a ratchet wheel (14) fixedly mounted on an input shaft of the power generator (9), a left gear shaft (22) and a right gear shaft (20) which are respectively rotatably mounted on the side plate connecting rod (6), spring pawl discs (11) are fixedly arranged at opposite ends of the left gear shaft (22) and the right gear shaft (20), and a plurality of small pawls (21) which are uniformly distributed and are matched with the ratchet wheel (14) for transmission are mounted on the end face of each spring pawl disc (11).

2. A knee exoskeleton for generating electricity based on negative power recovery as claimed in claim 1, wherein: the leg support transmission shaft is rotatably mounted on the inner wall of the thigh support (1) through a bearing, the end part of the shank support (8) and the end part of the rack (24) are fixedly connected to the leg support transmission shaft through keys, the gear turntable (17) is sleeved at the middle part of the leg support transmission shaft through a bearing, and the ratchet disc (3) is rotatably sleeved at one end, far away from the thigh support (1), of the leg support transmission shaft through the bearing.

3. A knee exoskeleton for generating electricity based on negative power recovery as claimed in claim 2, wherein: the rack (24) is of a quarter arc internal gear structure, and the central axis of the rack is coincident with the axis of the leg support transmission shaft.

4. A knee exoskeleton for generating electricity based on negative power recovery as claimed in claim 2, wherein: the bottom of the thigh support (1) is integrally provided with a thigh support extension section, and the transmission gear A (26) is rotatably arranged on the thigh support extension section and positioned on one side of a leg support transmission shaft.

5. A knee exoskeleton for generating electricity based on negative power recovery as claimed in claim 1, wherein: the thigh support is characterized in that an upper fixing frame is fixedly arranged on the front side of the middle of the thigh support (1), thigh binding bands (2) are connected to the rear side of the end portions of the upper fixing frame, a lower fixing frame is fixedly arranged on the front side of the middle of the shank support (8), and shank binding bands (7) are connected to the rear side of the end portions of the lower fixing frame.

6. A knee exoskeleton for generating electricity based on negative power recovery as claimed in claim 1, wherein: the motor tripod is characterized in that a motor tripod (12) and bearing seats (15) positioned on two sides of the motor tripod are fixedly arranged above the middle of the side plate connecting rod (6), a speed reducer (10) is fixedly connected to the input shaft end of the generator (9), the speed reducer (10) is fixedly arranged on the motor tripod (12), and a left gear shaft (22) and a right gear shaft (20) are respectively arranged on the two bearing seats (15) in a rotating mode through bearings.

7. A knee exoskeleton for generating electricity based on negative power recovery according to claim 1 or 6, wherein: the two ends of the side plate connecting rod (6) are fixedly connected to the middle parts of the two sides of the thigh support (1) through thigh support connecting rods (19) which are obliquely arranged.

8. A knee exoskeleton for generating electricity based on negative power recovery as claimed in claim 1, wherein: two transmission gears are rotatably arranged on the side plate (5) on one side, and three transmission gears are rotatably arranged on the side plate (5) on the other side.

9. A power generation method applied to the knee exoskeleton of any one of claims 1 to 8, comprising the main steps of:

S10, sleeving the thigh support (1) on the thigh part of a human body of a user, sleeving the shank support (8) on the shank part of the human body, and binding and fixing the thigh support and the shank support through the thigh binding belt (2) and the shank binding belt (7);

s20, a user walks on a flat ground with a normal walking gait, in a swinging stage of walking at a single-side shank position, the shank bracket (8) rotates unidirectionally relative to the thigh bracket (1), and a leg bracket transmission device positioned at one side of the thigh bracket (1) transmits the relative rotation to a power generation mechanism through a reversing transmission assembly at the corresponding side, so that a generator of the power generation mechanism is driven to rotate unidirectionally for a certain angle to generate electric energy;

S30, in a standing stage of walking at the same lower leg position, the lower leg support (8) rotates in opposite directions relative to the thigh support (1), and a leg support transmission device positioned at the other side of the thigh support (1) transmits the relative rotation to the power generation mechanism through a reversing transmission assembly at the corresponding side, so that a generator of the power generation mechanism is driven to rotate in opposite directions for a certain angle in a unidirectional manner to generate electric energy;

S40, the lower leg on the other side executes the step S20 and the step S30 to finish the same power generation process;

S50, repeatedly executing the steps S20 to S40 to realize alternate power generation of legs at two sides;

s60, after the power generation is completed, the thigh binding bands (2) and the shank binding bands (7) are loosened, and the knee joint exoskeleton is taken off.