Passive bionic variable stiffness hip joint assisted exoskeleton

Abstract

The application discloses a passive bionic variable stiffness hip joint assisting exoskeleton, which comprises a waist binding module, passive variable stiffness drivers, a thigh link and a thigh binding module. The waist binding module is provided with an adjusting mechanism in the circumferential direction, so that the width can be adjusted, and the positions of the passive variable stiffness drivers on both sides of the human hip can be adjusted, so that the passive variable stiffness drivers are aligned with the rotation center of the hip joint sagittal plane. The thigh binding module is worn on the human thigh, and the passive variable stiffness drivers on both sides are connected through the thigh link. Through the design of the passive variable stiffness drivers, the stiffness change range of the exoskeleton as a whole during walking can be adjusted, and the real stiffness change trend of the human hip joint can be simulated, so as to match the optimal stiffness of the human body. Meanwhile, a slip compensation structure is designed in the thigh binding module, which can offset the piston effect caused by the non-coincidence of the human-machine hip joint rotation center. The whole device is compact in structure and light in weight, and no additional power supply is needed in the assisting process, so that the gait of the person during walking can be more natural.

Description

Technical Field

[0002] This invention relates to the field of hip joint assistive exoskeleton technology, specifically a passive bionic variable stiffness hip joint assistive exoskeleton. Background Technology

[0004] A hip-assisted exoskeleton is a device worn on the waist and thigh to assist hip joint movement during walking or rehabilitation training. It can reduce the burden on the muscles around the hip joint and enhance human mobility.

[0005] Hip-assisted exoskeletons can be divided into active and passive exoskeletons based on whether they require power. Active exoskeletons use motors, pneumatic or hydraulic drives to assist the joint, rely on batteries for power, have complex control, and are larger and heavier. Passive exoskeletons provide assistance through the storage and release of energy by elastic elements in specific phases of the gait cycle. They do not require a power source, have a simple structure, are lightweight, and offer better wearing comfort and safety.

[0006] Chinese patent application number "CN202010607911.6" discloses "a passive variable stiffness energy storage assistive hip joint exoskeleton", which uses a cam and spring energy storage mechanism to realize energy storage and release during walking, and sets up a variable stiffness adjustment mechanism to adjust the joint output torque; however, its variable stiffness adjustment mechanism introduces components such as motor, reducer, worm gear, lead screw nut, etc., which still require power and the mechanism is relatively complex, and does not achieve true all-passive lightweight design.

[0007] Chinese patent application number "202511183135.0" discloses "a sliding telescopic sleeve device and a walking assistance device", which realizes the sliding extension and retraction of the sleeve device through two sleeves and a circulating ball structure. However, the structure is complex and can only achieve extension and retraction in one direction, and cannot achieve rotation.

[0008] Therefore, there is an urgent need for a passive exoskeleton solution for hip joint assistance that can achieve more comfortable assistance output by mimicking the actual torque change trend of the human hip joint without the need for a power source. It can also achieve manual and rapid adjustment of stiffness and has the ability to compensate for the relative displacement of the thigh bar along the thigh direction caused by the misalignment of the human-machine rotation center, thereby improving the effectiveness, comfort and applicability of assistance. Summary of the Invention

[0010] To address the aforementioned issues, this invention proposes a passive biomimetic variable stiffness hip joint assistive exoskeleton. By designing passive variable stiffness actuators on both sides of the hip joint, the overall stiffness variation range of the exoskeleton during walking can be adjusted and the stiffness variation trend of the human hip joint can be imitated to match the optimal stiffness of the human body, making the gait more natural during walking.

[0011] This invention relates to a passive biomimetic variable stiffness hip joint assistive exoskeleton, comprising a waist belt worn around the waist, thigh binding modules worn on both sides of the thighs, and passive variable stiffness actuators located on both sides of the hip. The passive variable stiffness actuators are hinged to the actuator connectors on both sides of the waist to form a rotating pair, with the axis of rotation along the front-back direction; the actuator connectors on both sides are suspended from the waist belt via straps; the passive variable stiffness actuators on both sides are also connected to the thigh binding straps via thigh connecting rods.

[0012] The passive variable stiffness actuator is used to provide hip joint assistance for the lower limbs. It has a disc-shaped outer shell consisting of an upper actuator housing, a lower actuator housing, and a cam ring between the two, which are fixedly connected, as well as a passive variable stiffness adjustment mechanism installed inside.

[0013] The passive variable stiffness adjustment mechanism includes a leaf spring support frame, an arc-shaped leaf spring, a first needle roller bearing, a fulcrum adjustment rod, a second needle roller bearing, and a manual stiffness adjustment knob. The leaf spring support frame is a ring structure, housing two arc-shaped leaf springs. The outer rings of the two springs are flush with the inner wall of the support frame, and their ends are fixed to the inner wall at opposite positions. An opening is located at the front end of the two leaf springs on the support frame wall. The first needle roller bearing is placed within this opening, its shaft parallel to the axis of the support frame. The first needle roller bearing is confined within the opening by the inner ring of a cam ring and the outer wall of the front end of the leaf spring.

[0014] The aforementioned leaf spring support frame has a stiffness adjustment flange and an output flange fixedly installed at both ends; both are connected to the upper and lower housings of the driver respectively via bearings to form a rotating pair; the output flange is fixedly connected to the top of the thigh connecting rod; thus, the rotation of the human thigh drives the thigh connecting rod to rotate, which in turn drives the output flange to rotate, ultimately realizing the rotation of the leaf spring support frame. During the rotation of the leaf spring support frame, the inner ring contour of the cam ring squeezes the first needle roller bearing, causing the first needle roller bearing to generate radial displacement within the opening, which in turn squeezes the front end of the leaf spring to generate torque.

[0015] The fulcrum adjusting rod is located within the leaf spring support frame; second needle roller bearings are installed at both ends of the fulcrum adjusting rod; the second needle roller bearings form a rolling pair with the two leaf springs. A D-shaped shaft and a cylindrical shaft are designed at relative positions on the fulcrum adjusting rod; the cylindrical shaft is coaxially connected to the output flange to form a rotating pair. The D-shaped shaft, through a through-hole on the inner end face of the stiffness adjusting flange, is placed within the central cavity designed inside the stiffness adjusting flange. The end of the D-shaped shaft has a cylindrical section, which connects with the through-hole at the end of the stiffness adjusting flange to form a rotating pair.

[0016] The manual stiffness adjustment knob has a positioning plate at its end; the end face of the manual stiffness adjustment knob has a D-shaped hole, and a first return spring is installed in the D-shaped hole. The end of the manual stiffness adjustment knob and the end positioning plate are respectively inserted into the central cavity through the center hole on the outer end face of the stiffness adjustment flange and the slots on both sides of the center hole, and the D-shaped shaft enters the D-shaped hole to compress the first return spring; at this time, rotating the manual stiffness adjustment knob drives the fulcrum adjustment rod to rotate, and the stiffness variation range is adjusted by the second needle roller bearings at both ends of the fulcrum adjustment rod cooperating with the two leaf springs at different circumferential positions.

[0017] After the two positioning plates are staggered during the above process, the manual stiffness adjustment knob is released. At this time, the first reset spring rebounds, causing the positioning plates on both sides of the manual stiffness adjustment knob to engage with the two opposite slots in the toothed groove designed on the outer circumferential side of the central cavity, thereby achieving circumferential positioning of the stiffness adjustment flange.

[0018] The advantages of this invention are:

[0019] 1) The passive variable stiffness actuators on both sides of the passive bionic hip joint assistive exoskeleton of this invention are connected to the actuator connectors on both sides via positioning pins and first deep groove ball bearings, realizing the adduction and abduction functions of the hip joint. The actuators of this exoskeleton utilize the elastic deformation of the circular arc leaf spring for energy storage and release, resulting in a more compact structure compared to other linear elastic elements. The cam disk contour curves in the passive variable stiffness actuators on both sides match the torque of a normal human hip joint, and the overall stiffness can change with the stiffness of the human hip joint. No power supply is required, and the range of changes in the overall stiffness of the exoskeleton during walking can be adjusted via a manual stiffness adjustment knob to match the optimal stiffness of the human body.

[0020] 2) The left and right thigh binding modules in the passive bionic hip joint assistive exoskeleton of this invention adopt a quick-release and quick-install design, which is convenient for putting on, taking off, and maintenance. Compared with the prior art, this exoskeleton is equipped with a sliding compensation module, which can counteract the piston effect caused by the misalignment of the rotation center of the human-machine hip joint. This compensation module can not only slide along the axis, but also rotate along the axis, which is more flexible.

[0021] 3) The width-adjustable tube in the passive bionic hip joint assistive exoskeleton of this invention can adjust the width of the exoskeleton waist to accommodate people with different waist sizes; the side telescopic tube can adjust the position of the left and right passive variable stiffness actuators along the axis to align with the rotation center of the hip joint coronal axis. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of the passive biomimetic variable stiffness hip joint assistive exoskeleton of the present invention;

[0024] Figure 2 This is a front view of the overall structure of the passive biomimetic variable stiffness hip joint assistive exoskeleton of the present invention;

[0025] Figure 3 This is a top view of the overall structure of the passive biomimetic variable stiffness hip joint assistive exoskeleton of the present invention;

[0026] Figure 4 This is a schematic diagram of the overall structure of the passive variable stiffness actuator in the passive bionic variable stiffness hip joint assistive exoskeleton of the present invention.

[0027] Figure 5 This is a side sectional view of the overall structure of the passive variable stiffness actuator.

[0028] Figure 6 Exploded view of a passive variable stiffness actuator;

[0029] Figure 7 This is a schematic diagram of the internal structure of the variable stiffness adjusting flange in a passive variable stiffness actuator.

[0030] Figure 8 This is a schematic diagram of the thigh binding module structure in the passive biomimetic variable stiffness hip joint assistive exoskeleton of the present invention;

[0031] Figure 9 A schematic diagram of the lock head and lock seat structure of the quick-release buckle module in the thigh binding module;

[0032] Figure 10 This is a schematic diagram illustrating the engagement method between the lock head and lock seat in the snap-on quick-release module.

[0033] Figure 11 This is a schematic diagram illustrating the locking mechanism between the lock head and the sliding block in the snap-on quick-release module.

[0034] Figure 12 This is a cross-sectional view of the locking engagement between the lock head and the sliding block in the snap-on quick-release module.

[0035] In the picture:

[0036] 1-Waist binding module; 2-Left passive variable stiffness actuator; 3-Right passive variable stiffness actuator; 4-Left thigh rod; 5-Right thigh rod; 6-Left thigh binding module; 7-Side thigh binding module.

[0037] 101-Waist belt fixing tube; 102-Left side width adjustment tube; 103-Right side width adjustment tube; 104-Left side bend tube; 105-Right side bend tube; 106-Left side telescopic tube; 107-Right side telescopic tube; 108-Left side drive connector; 109-Right side drive connector; 110-Waist locking buckle; 111-Side locking buckle; 112-Waist belt.

[0038] 201-Driver upper housing; 202-Driver lower housing; 203-Cam ring; 204-Passive variable stiffness adjustment mechanism; 205-Manual stiffness adjustment knob; 204a-Leaf spring support frame; 204b-Circular arc leaf spring; 204c-First needle roller bearing; 204d-Pivot point adjusting rod; 204e-Second needle roller bearing; 204f-Stiffness adjustment flange; 204g-Output flange; 204f1-Central cavity; 204f2-Adjusting hole; 204f3-Insertion slot; 204f4-Gear groove; 205a-Rotor; 205b-First reset compression spring; 205c-Rectangular positioning plate.

[0039] 601-Sliding compensation module; 602-Snap fastener module; 603-Thigh binding component; 604-Binding strap; 601a-Upper optical axis fixing component; 601b-Lower optical axis fixing component; 601c-Sliding optical axis; 601d-Sliding block; 602a-Lock seat; 602b-Lock head; 602c-T-slot; 602d-Second reset spring; 602e-Limiting block; 602f-Sliding channel; 602g-Dovetail groove. Detailed Implementation

[0041] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0042] This invention relates to a passive biomimetic variable stiffness hip joint assistive exoskeleton, comprising a waist restraint module 1, a left passive variable stiffness actuator 2, a right passive variable stiffness actuator 3, a left thigh rod 4, a right thigh rod 5, a left thigh restraint module 6, and a right thigh restraint module 7, as shown below. Figure 1 , Figure 2 As shown.

[0043] The waist binding module 1 includes a waist belt fixing tube 101, a left width adjusting tube 102, a right width adjusting tube 103, a left curved tube 104, a right curved tube 105, a left telescopic tube 106, a right telescopic tube 107, a left driver connector 108, a right driver connector 109, a waist locking buckle 110, a side locking buckle 111, and a waist belt 112. Figure 3 As shown.

[0044] The waist belt 112 has an overall C-shaped structure and is worn around the waist. The back of the waist belt 112 is a flat back-fitting part, and the left and right sides are arc-shaped waist-fitting parts; at the same time, the opposite ends of the waist-fitting parts on both sides are equipped with straps, which can be inserted through the plug to further fix the waist belt 112 in the position of the waist.

[0045] The waist-fixing round tube 101 is arranged in the left-right direction, and its left and right parts are fixedly connected to the back-fitting part of the waist belt 112 by bolts to ensure effective force transmission between the two. The left and right ends of the waist-fixing round tube 101 have equally spaced gaps in the circumferential direction, forming a multi-branch structure. The ends of the left width-adjusting round tube 102 and the right width-adjusting round tube 103 are respectively coaxially inserted into the ends of the waist-fixing round tube 101, and the two are locked and fixed by the waist-fixing locking buckle 110 sleeved on the end of the waist-fixing round tube 101.

[0046] The front ends of the left width adjusting tube 102 and the right width adjusting tube 103 are respectively inserted and fixed to the short ends of the left bend tube 104 and the right bend tube 105. The long ends of the left bend tube 104 and the right bend tube 105 extend downwards and forwards towards the waist belt, with equally spaced circumferential gaps at the ends, forming a multi-branch structure. The ends of the left telescopic tube 106 and the right telescopic tube 107 are respectively inserted and fixed to the long ends of the left bend tube 104 and the right bend tube 105, and are locked and fixed by side locking buckles 111 fixedly sleeved on the long ends of the left bend tube 104 and the right bend tube 105. The front ends of the left telescopic tube 106 and the right telescopic tube 107 are respectively inserted and fixed to the cylindrical portions of the left driver connector 108 and the right driver connector 109.

[0047] The aforementioned left-side actuator connector 108 and right-side actuator connector 109 are respectively located on the left and right sides of the human hip joint. They have identical structures, with a connector at the top of their cylindrical portion. The connector has an insertion port, through which a nylon braided strap passes. This strap passes through the insertion port and also through an insertion port designed at the lower edge of the waist-fitting part on the same side, and the two ends are then connected and fixed, thus achieving the connection between the left-side actuator connector 108 and right-side actuator connector 109 and the waist belt 112. Slots are designed at the bottom of the cylindrical portion of the left-side actuator connector 108 and right-side actuator connector 109 for connecting the passive variable stiffness actuator on the same side.

[0048] With the waist binding module 1 of the above structure, the axial positions of the left width adjustment tube 102 and the right width adjustment tube 103 can be adjusted by loosening the waist locking buckle 110, thereby adjusting the width of the waist belt 112; the axial positions of the left telescopic tube 102 and the right telescopic tube 103 can be adjusted by loosening the side locking buckle 111, thereby adjusting the height of the left passive variable stiffness actuator 2 and the right passive variable stiffness actuator 3.

[0049] The left passive variable stiffness actuator 2 and the right passive variable stiffness actuator 3 have the same structure and are used to provide lower limb hip joint assistance. They include an upper actuator housing 201, a lower actuator housing 202, a cam ring 203, a passive variable stiffness adjustment mechanism 204, and a manual stiffness adjustment knob 205. Figures 4-7 As shown.

[0050] The upper housing 201 and lower housing 202 of the driver are circular shells, coaxially arranged with their recessed sides facing each other, and a cam ring 203 is coaxially arranged between them. The outer ring of the cam ring 203 is circular, and the inner ring has a customized profile; further, the three are coaxially fixed together by bolts passing through the threaded holes in the circumference of the three to form an integral disc-shaped shell. The outer ring of the cam ring 203 has shoulders on both sides, which respectively cooperate with the shoulders designed on the inner circumference of the upper housing 201 and the lower housing 202 of the driver for positioning, ensuring the coaxiality between the three and facilitating the clamping of the cam ring 203 when the three are fixed.

[0051] The passive variable stiffness adjustment mechanism 204 is coaxially mounted inside the housing. The passive variable stiffness adjustment mechanism 204 includes a leaf spring support frame 204a, an arc leaf spring 204b, a first needle roller bearing 204c, a fulcrum adjustment rod 204d, a second needle roller bearing 204e, a stiffness adjustment flange 204f, and an output flange 204g.

[0052] The leaf spring support frame 204a is a ring structure, with two arc-shaped leaf springs 204b installed inside. The outer rings of the two arc-shaped leaf springs 204b are in contact with the inner wall of the leaf spring support frame 204a, and their ends are respectively connected and fixed to the inner wall of the leaf spring support frame 204a at opposite positions. An opening is located on the wall of the leaf spring support frame 204a at the front end of the two leaf springs, and a first needle roller bearing 204c is placed in the opening. The rotation axis of the first needle roller bearing 204c is arranged parallel to the axis of the leaf spring support frame 204a.

[0053] The aforementioned leaf spring support frame 204a is coaxially placed inside the housing. The first needle roller bearing 204c contacts the inner ring of the cam ring 203, and is confined within an opening by the inner ring of the cam ring 203 and the outer wall of the front end of the leaf spring 204b. Since the inner ring of the cam ring 203 has a custom profile, during the rotation of the leaf spring support frame 204a, the specific contour of the inner ring of the cam ring 203 will compress the first needle roller bearing 204c, causing the first needle roller bearing 204c to generate radial displacement within the opening. This, in turn, generates a specific torque by compressing the front end of the leaf spring 204b. A rectangular groove is designed at the contact point between the outer wall of the front end of the leaf spring 204b and the first needle roller bearing 204c, allowing the first needle roller bearing 204c to contact and compress the leaf spring 204b with the bottom plane of the rectangular groove, thus optimizing the overall force transmission effect.

[0054] The fulcrum adjusting rod 204d is set perpendicular to the axis of the leaf spring support frame 204a and is located inside the leaf spring support frame 204a. The fulcrum adjusting rod 204d has U-shaped joints at both ends, and a second needle roller bearing 204e is installed in the U-shaped joint through a rotating shaft; the rotating shaft of the second needle roller bearing 204e is arranged parallel to the axis of the leaf spring support frame 204a, and its wall surface contacts the inner rings of the two leaf springs 204b to form a fulcrum, and can roll along the inner ring wall surface of the leaf springs 204b.

[0055] The pivot adjusting rod 204d has a D-shaped shaft and a cylindrical shaft respectively designed at its middle relative positions along the axis of the leaf spring support frame 204a. The cylindrical shaft is placed in the circular groove at the inner end of the output flange 204g, and is connected to the circular groove by a second deep groove ball bearing to form a rotating pair. Four circumferentially spaced connecting beams of the output flange 204g are respectively connected and fixed by screws to the corresponding screw holes on the inner end face of the leaf spring support frame 204a. At the same time, the output flange 204 and the center hole of the lower housing 202 of the driver are connected by a crossed roller bearing 229 to form a rotating pair.

[0056] The D-shaped shaft is placed inside the central cavity 204f1 of the stiffness adjusting flange 204f through a through hole on the inner end face of the stiffness adjusting flange 204f. The end of the D-shaped shaft has a cylindrical section, which is connected to the end through hole of the stiffness adjusting flange via a first deep groove ball bearing to form a rotating pair. Four circumferentially spaced connecting beams of the stiffness adjusting flange 204f are respectively connected and fixed to the corresponding threaded holes on the outer end face of the leaf spring support frame 204a via screws. Simultaneously, the outer wall of the central cavity of the stiffness adjusting flange 204f is connected to the central hole of the upper housing 201 of the actuator via a crossed roller bearing to form a rotating pair. The outer end face of the stiffness adjusting flange 204f has an adjusting hole 204f2 communicating with the central cavity 204f1. A slot 204f3 communicating with both the adjusting hole 204f2 and the central cavity 204f1 is provided at a circumferentially opposite position to the adjusting hole 204f2 for installing a manual stiffness adjusting knob 205.

[0057] The main body of the manual stiffness adjustment knob 205 is a columnar structure, with a rotating rod 205a at a circumferential position at its end for manually rotating the stiffness adjustment knob 205. A D-shaped hole is designed on the front end face of the stiffness adjustment knob 205, and a first return spring 205b is installed inside the D-shaped hole; simultaneously, two rectangular positioning plates 205c are designed at a circumferential position at the front end of the stiffness adjustment knob 205.

[0058] The front end of the stiffness adjustment knob 205 and the rectangular positioning plates 205c on both sides of the front end can be inserted into the central cavity 204f1 through the center hole of the outer end face of the stiffness adjustment flange 204f and the insertion slots on both sides of the center hole, respectively. During the process, the D-shaped shaft enters the D-shaped hole and compresses the first reset spring 205b. At this time, rotating the stiffness adjustment knob 205 can drive the fulcrum adjustment rod 204d to rotate. Through the second needle roller bearings 204e at both ends of the fulcrum adjustment rod 204d and the two leaf springs 204b at different circumferential positions, the stiffness variation range can be adjusted. During the above process, the two rectangular positioning plates 205c are staggered from the insertion slot 204f3. Then, the stiffness adjustment knob 205 is released. At this time, the first reset spring 205b rebounds, so that the two side plates 205c of the stiffness adjustment knob 205 can be aligned with the toothed groove 204f4 on the outer side of the central cavity 204f1 of the stiffness adjustment flange 204f, thus achieving circumferential positioning of the manual stiffness adjustment knob 205. At this time, the D-shaped shaft is still located in the D-shaped hole, and the first reset spring 205b is still in a compressed state.

[0059] The left passive variable stiffness actuator 2 and the right passive variable stiffness actuator 3 of the above structure are respectively connected to the slots below the left actuator connector 108 and the right actuator connector 109 via plugs designed on the outer wall of the lower housing 202 of the actuator, forming a rotating pair through a rotating shaft with the axis of rotation along the front-back direction. The left passive variable stiffness actuator 2 and the right passive variable stiffness actuator 3 are respectively connected to the left thigh binding module 6 and the right thigh binding module 7 installed on the left and right thighs of the human body via the left thigh rod 4 and the right thigh rod 5.

[0060] Both the left thigh rod 4 and the right thigh connecting rod 5 are curved aluminum alloy rods that extend from top to bottom along the side of the hip to the front of the thigh, their outlines enclosing about one-quarter of the thigh. The upper ends of the left thigh rod 4 and the right thigh rod 5 have connecting surfaces that are fixed to the output flange 204g in the passive variable stiffness actuator. Therefore, when the thigh rotates, it drives the thigh connecting rod to rotate, which in turn drives the output flange 204g to rotate, ultimately causing the leaf spring support frame 204a to rotate.

[0061] The left thigh binding module 6 and the right thigh binding module 7 have the same structure, including a sliding compensation module 601, a quick-release buckle module 602, a thigh binding component 603, and a binding strap 604. Figure 8 As shown. The binding strap is a medical leg-correcting binding strap, which has a C-shaped structure and is fitted onto the thigh. An arc-shaped plate-like thigh binding component 603 is fixedly installed on its side wall. The inner arc surface of the thigh binding component 603 is connected to the outer wall of the medical leg-correcting binding strap by Velcro. The outer arc surface is connected to the sliding compensation module 601 by a quick-release buckle module 602.

[0062] The slip compensation module 601 includes an upper optical axis fixing component 601a, a lower optical axis fixing component 601b, a slip optical axis 601c, and a slip block 601d. The slip block 601d is a dovetail slider with a bearing seat on its top surface. The slip optical axis 601c is parallel to the platform and coaxially mounted in an opening on the bearing seat, with the two connected by a linear bearing to form a sliding pair. The bottom end of the slip optical axis 601c is inserted and fixed into a blind hole on the top of the lower optical axis fixing component 601b; the top end of the slip optical axis 601c passes through a through hole on the upper optical axis fixing component 601a, and a fixing ring is used to limit its movement.

[0063] The left thigh binding module 6 and the right thigh binding module 7 of the above structure are connected and fixed to the bottom connecting surfaces of the left thigh rod 4 and the right thigh connecting rod 5 respectively by bolts through the side connecting surfaces of the upper optical axis fixing member 601a and the lower optical axis fixing member 601b. Thus, the sliding pair formed by the sliding block 601d and the sliding optical axis 601c ensures the range of motion between the human thigh binding point and the thigh rod. When actually wearing this exoskeleton and walking, the sliding block 601d can slide along the optical axis as the distance between the human thigh binding point and the hip joint rotation center changes, adaptively compensating for the slippage of the binding straps caused by the difficulty in aligning the human-machine joint rotation center, thereby reducing the friction of the binding straps on the human thigh and optimizing the force transmission between the human thigh and the thigh connecting rod.

[0064] The aforementioned sliding block 601d, together with the lock base 602a and the lock head 602b, constitutes a snap-on quick-release module 602, such as... Figures 9-11 As shown. The sliding block 601d is designed on the bottom surface of the aforementioned sliding block 601d and arranged along the sliding optical axis 601c. The sliding block 601d is slidably connected to the dovetail groove 601g designed on the top surface of the lock seat 602a; the lock seat 602a has an opening for screws to connect and fix it to the back side of the thigh binding 603. Simultaneously, a T-shaped groove 602c is designed on the bottom surface of the lock seat 602a perpendicular to the dovetail groove 602g, and the head (wide end) of the T-shaped groove 602c communicates with the side wall of the lock seat 602a. A T-shaped lock head 602b matching its size is provided in the T-shaped groove 602c, and the end face of the tail end (narrow end) of the lock head 602b is connected to the end face of the tail end of the T-shaped groove 602c by a second reset spring 602d. A limit block 602e is designed on the side of the tail end of the lock head 602b.

[0065] The aforementioned lock head 602b is disposed within the T-slot 602c, and its end limiting block 602e is placed through an opening in the T-slot 602c within a sliding channel 602f on the lock seat 602a that communicates with the dovetail groove 602g. Figure 12As shown. When the thigh binding 603 and the sliding compensation module 601 are connected by a dovetail joint, the limiting block 602e moves from the sliding channel 602f into the dovetail groove 602g under the elastic force of the second return spring 602d, and is located in the notch opened on the side of the sliding block 601d, thereby locking the sliding block 601d and the lock seat 602a. When the lock head 602b is pushed, the second return spring 602d is compressed, the limiting block 602e moves in the opposite direction, and can completely enter the sliding channel 602f. At this time, the limiting block 602e leaves the side opening of the sliding block 601d, and the sliding block 601d and the lock seat 602a are unlocked, realizing the quick disassembly of the thigh binding 603.

[0066] This invention relates to a passive bionic variable stiffness hip joint assistive exoskeleton. Through the left-side passive variable stiffness actuator 2 and the right-side passive variable stiffness actuator 3, the curvature radius of the inner contour of the cam ring 203 changes, causing a pair of miniature needle roller bearings on the leaf spring support frame 204a to compress the arc-shaped leaf spring 204b during negative work of the human lower limb hip joint, storing energy; during positive work, the arc-shaped leaf spring 204b returns to its original shape, releasing energy to provide assistance. Furthermore, by pressing down the manual stiffness adjustment knob 205 until the two rectangular plates reach the central cavity 204f1, rotating the manual stiffness adjustment knob 205 drives the fulcrum adjustment rod 204d to rotate, thereby causing the second needle roller bearings 204e at both ends of the fulcrum adjustment rod 204d to contact the two leaf springs 204b at different circumferential positions. This proportionally amplifies or reduces the range of stiffness changes during movement to match the optimal stiffness assistance conditions; after adjustment, releasing the manual stiffness adjustment knob 205 locks the exoskeleton. The entire device of this invention is compact and lightweight, and requires no additional power source for the assistance process. To make the gait more natural during walking, the inner contour of the cam ring 203 is designed based on the actual torque changes of the hip joint during human lower limb movement.

Claims

1. A passive biomimetic variable stiffness hip joint assistive exoskeleton, comprising a waist belt worn around the waist and thigh binding modules worn on both thighs, characterized in that: It also includes passive variable stiffness actuators located on both sides of the hip; the passive variable stiffness actuators are hinged to the actuator connectors on both sides of the waist to form a rotating pair, with the axis of rotation along the front-back direction; the actuator connectors on both sides are suspended from the waist belt by straps; the passive variable stiffness actuators on both sides are also connected to the thigh straps on both sides through thigh linkages. The passive variable stiffness actuator is used to provide hip joint assistance for the lower limbs. It has a disc-shaped outer shell with an upper actuator housing, a lower actuator housing, and a cam ring connecting the two. An internal passive variable stiffness adjustment mechanism is also included. The passive variable stiffness adjustment mechanism comprises a leaf spring support frame, an arc-shaped leaf spring, a first needle roller bearing, a fulcrum adjustment rod, a second needle roller bearing, and a manual stiffness adjustment knob. The leaf spring support frame is a ring structure with two arc-shaped leaf springs installed inside. The outer rings of the two arc-shaped leaf springs are fitted against the inner wall of the leaf spring support frame, and their ends are respectively fixed to the inner wall of the leaf spring support frame at opposite positions. An opening is located at the front end of the two leaf springs on the wall of the leaf spring support frame. The first needle roller bearing is placed in the opening, and its shaft is arranged parallel to the axis of the leaf spring support frame. The first needle roller bearing is confined within the opening by the inner ring of the cam ring and the outer wall of the front end of the leaf spring. The aforementioned leaf spring support frame has a stiffness adjustment flange and an output flange fixedly installed at both ends; both are connected to the upper housing and lower housing of the driver respectively through bearings to form a rotating pair; and the output flange is fixedly connected to the top of the thigh connecting rod; thus, the rotation of the human thigh drives the rotation of the thigh connecting rod, which in turn drives the output flange to rotate, ultimately realizing the rotation of the leaf spring support frame; during the rotation of the leaf spring support frame, the inner ring contour of the cam ring squeezes the first needle roller bearing, causing the first needle roller bearing to generate radial displacement in the opening, and then the first needle roller bearing squeezes the front end of the leaf spring to generate torque; The fulcrum adjusting rod is located inside the leaf spring support frame; second needle roller bearings are installed at both ends of the fulcrum adjusting rod; the second needle roller bearings and the two leaf springs form a rolling pair; a D-shaped shaft and a cylindrical shaft are designed at opposite positions on the fulcrum adjusting rod; the cylindrical shaft is coaxially connected to the output flange to form a rotating pair; the D-shaped shaft is placed in the central cavity designed inside the stiffness adjusting flange through a through hole on the inner end face of the stiffness adjusting flange, and the end of the D-shaped shaft has a cylindrical section, which is connected to the end through hole of the stiffness adjusting flange to form a rotating pair; The manual stiffness adjustment knob has a positioning plate at its end; the end face of the manual stiffness adjustment knob has a D-shaped hole, and a first return spring is installed in the D-shaped hole; the end of the manual stiffness adjustment knob and the end positioning plate are respectively inserted into the central cavity through the center hole on the outer end face of the stiffness adjustment flange and the slots on both sides of the center hole, and the D-shaped shaft enters the D-shaped hole to compress the first return spring; at this time, rotating the manual stiffness adjustment knob drives the fulcrum adjustment rod to rotate, and the stiffness variation range is adjusted by the second needle roller bearings at both ends of the fulcrum adjustment rod cooperating with the two leaf springs at different circumferential positions; after the two positioning plates are staggered in the above process, the manual stiffness adjustment knob is released, and the first return spring rebounds, so that the positioning plates on both sides of the manual stiffness adjustment knob cooperate with the two opposite slots in the toothed grooves designed on the outer circumferential side of the central cavity, realizing the circumferential positioning of the stiffness adjustment flange.

2. The passive biomimetic variable stiffness hip joint assistive exoskeleton as described in claim 1, characterized in that: The waist belt is equipped with a waist belt fixing tube, a width adjusting tube, a bent tube, a telescopic tube, and a right-side telescopic tube. The waist fixing tube runs horizontally and is bolted to the back of the waist belt. The left and right ends of the waist fixing tube are inserted into the ends of two horizontally running width adjusting tubes and secured with locking buckles, allowing for axial adjustment of the width adjusting tubes. The front ends of the two width adjusting tubes are inserted into the ends of two bent tubes. The front ends of the two bent tubes extend from both sides of the waist belt towards the actuator connectors and are inserted into the ends of the telescopic tubes on both sides of the waist belt, secured with locking buckles, allowing for axial adjustment of the telescopic tubes. The front ends of the two telescopic tubes are fixed to the actuator connectors on both sides of the waist belt. This allows for adjustment of the waist belt width and the height of the passive variable stiffness actuators on both sides.

3. The passive biomimetic variable stiffness hip joint assistive exoskeleton as described in claim 1, characterized in that: The outer ring of the cam ring has shoulders on both sides that are designed to cooperate with the shoulders designed on the inner circumferential edge of the upper and lower housings of the driver for positioning.

4. The passive biomimetic variable stiffness hip joint assistive exoskeleton as described in claim 1, characterized in that: The contact surface between the first needle roller bearing and the leaf spring is a flat surface designed on the outer wall of the leaf spring.

5. The passive biomimetic variable stiffness hip joint assistive exoskeleton as described in claim 1, characterized in that: The thigh link and the thigh binding strap are connected by a sliding compensation module. The sliding compensation module includes an upper optical axis fixing component, a lower optical axis fixing component, a sliding optical axis, and a sliding block. The sliding block is designed with a bearing seat, and the sliding optical axis is installed in the opening on the bearing seat. The two are connected by a linear bearing to form a sliding pair. The bottom and top ends of the sliding optical axis are respectively connected to the lower optical axis fixing component and the upper optical axis fixing component. The upper and lower optical axis fixing components are connected to the bottom end of the thigh link. The sliding pair formed by the sliding block and the sliding optical axis ensures the range of motion between the human thigh binding area and the thigh link.

6. The passive biomimetic variable stiffness hip joint assistive exoskeleton as described in claim 5, characterized in that: The sliding block is connected to the thigh strap via a quick-release mechanism. First, a dovetail block is designed on the sliding block, which mates with a dovetail groove on the lock seat. The lock seat is fixed to the strap. A T-shaped groove is designed on the bottom surface of the lock seat perpendicular to the dovetail groove, with the head of the T-shaped groove communicating with the side wall of the lock seat. A matching T-shaped lock head is installed within the T-shaped groove, with the tail end face of the lock head connected to the tail end face of the T-shaped groove via a second return spring. A limit block is designed on the side of the tail end of the lock head. The limit block, through an opening in the T-shaped groove, is positioned within an opening on the lock seat that mates with the dovetail groove. Within the sliding channel connected to the tail groove; after the thigh binding and the sliding compensation module are connected by a dovetail joint, the limiting block moves from the sliding channel into the dovetail groove under the elastic force of the second return spring, and is located in the notch opened on the side of the sliding block, thereby realizing the locking between the sliding block and the lock seat; when the lock head is pushed, the second return spring is compressed, the limiting block moves in the opposite direction, and can completely enter the sliding channel. At this time, the limiting block leaves the side opening of the sliding block, and the sliding block and the lock seat are unlocked, realizing the quick disassembly of the thigh binding.

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