Wearable flexible lower limb gravity balance exoskeleton

Abstract

The application discloses a wearable flexible lower limb gravity balance exoskeleton and relates to the field of exoskeleton robots.The exoskeleton robot comprises a flexible garment, a knee joint binding mechanism, a Bowden cable transmission mechanism and a gravity balance device.The flexible garment is worn on the upper body of a human body, provides a stress anchor point for the gravity balance device and guarantees the stability of wearing.The knee joint binding mechanism is installed at the knee joint of the lower limb of the human body and connects the gravity balance device with the knee joint.The Bowden cable transmission mechanism is distributed on the front side of the thigh and provides assistance for the flexion of the hip joint.The Bowden cable transmission mechanism is connected with the knee joint binding mechanism.The gravity balance device is installed on the front side of the flexible garment and assists the flexion of the hip joint.The gravity balance mechanism is combined with the Bowden cable transmission mechanism and adopts a bionic driving mode to simulate the force line direction of the hip flexor muscle of the lower limb.The application adopts a variable stiffness design, and elastic elements and flexible mechanisms are matched with the motion change of the human body, so that the fitting degree of the exoskeleton with the human body is higher, and the assistance and safety are improved.

Description

Technical Field

[0001] This invention relates to the field of exoskeleton robots, and more particularly to a wearable flexible lower limb gravity-balanced exoskeleton. Background Technology

[0002] As China's population ages, problems such as lower limb muscle weakness due to physiological decline seriously affect the daily activities of the elderly. To help the elderly walk, wearable devices have been proposed, among which lower limb exoskeletons play an important role in promoting the recovery of normal function.

[0003] Currently, most lower limb exoskeletons are rigid structures, generally quite heavy, which increases the wearer's energy consumption as an additional burden. At the same time, rigid structures restrict the freedom of joint movement, thereby altering the wearer's natural gait pattern. Flexible lower limb exoskeletons, on the other hand, are gaining increasing attention due to their advantages such as light weight and strong adaptability to human movement.

[0004] Therefore, those skilled in the art are dedicated to providing a wearable flexible lower limb gravity balance exoskeleton for the rehabilitation of lower limb motor dysfunction, which meets the requirements of being lightweight, highly flexible, and providing more natural assistance. It can compensate for the weight of the hip joint during walking, producing a lower limb gravity balance effect and reducing the wearer's energy consumption during walking. Summary of the Invention

[0005] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is that the rigid structure of traditional exoskeletons is difficult to adapt to the movement changes of the human body at different stages and is difficult to adapt to complex external environments.

[0006] To achieve the above objectives, the present invention provides a wearable flexible lower limb gravity-balancing exoskeleton, characterized in that the wearable flexible lower limb gravity-balancing exoskeleton is symmetrical about the human body and includes flexible clothing, a knee joint binding mechanism, a Bowden cable transmission mechanism, and a gravity-balancing device, wherein...

[0007] The flexible garment is worn on the upper body and provides force anchor points for the gravity balance device, ensuring the stability of the garment.

[0008] The knee joint binding mechanism is installed at the knee joint of the human lower limb, and the gravity balance device is connected to the knee joint.

[0009] The Bowden cable drive mechanism is located on the front of the thigh and provides assistance for hip flexion. The Bowden cable drive mechanism is connected to the knee joint binding mechanism.

[0010] The gravity balancing device is installed on the front of the flexible garment to assist hip joint flexion. The gravity balancing mechanism and the Bowden line transmission mechanism are combined and adopt a biomimetic drive method to mimic the force line direction of the hip flexor muscles of the lower limb.

[0011] Furthermore, the flexible garment includes shoulder straps, a chest fixing strap, a waist fixing strap, and a waist belt. The shoulder straps are fixedly connected to the chest fixing strap, and the waist fixing strap is fixedly connected to the waist belt, providing stable anchor points while ensuring that the flexible garment fits closely to the upper body of the human body.

[0012] Furthermore, the knee joint binding mechanism includes an upper knee, a middle knee, and a lower knee. The upper knee and the lower knee are composed of a low-temperature thermoplastic plate and a sponge liner. The middle knee includes a support spring. The two ends of the middle knee are respectively connected to the low-temperature thermoplastic plates of the upper knee and the lower knee, which improves wearing comfort while ensuring firmness. The upper knee is connected to the lower end of the Bowden cable in the Bowden cable transmission mechanism.

[0013] Furthermore, the gravity balancing device includes a fixed assembly module and a sliding assembly module. The fixed assembly module includes a waist fixing shell, a guide rod fixing plate, and a sliding fixing component. The sliding assembly module includes a sliding plate, a guide rod, a spring, a guide pulley, a lead screw, a rack, and a pressure hole plate. The sliding plate of the sliding assembly module is used to fix the components of the gravity balancing device. The sliding plate is fitted with holes on both sides of the waist fixing shell. The number of sliding fixing components and guide pulleys is the same, and the number of each is set to three.

[0014] Furthermore, the guide pulley is fixed to the outside of the sliding plate by the sliding fastener via bolts, for defining the transmission path of the Bowden line; the gear transmission plate is embedded in the upper part of the sliding plate, for fixing the inner mechanism; the gear spool shaft on the inner side of the sliding plate connects the two gears and one spool to the gear transmission plate, for tightening or extending the Bowden line during driving.

[0015] Furthermore, the upper end of the guide rod is connected to the guide rod fixing plate by bolts. The pressure plate has three holes through which two guide rods and one lead screw pass. Two springs are respectively fitted on the two guide rods to define the compression path of the springs.

[0016] Furthermore, the two racks fixed inside the waist fixing shell are used to mesh with the gear, and when the spring is compressed or relaxed, the rotation of the gear drives the sliding plate to slide up and down.

[0017] Furthermore, the wearable flexible lower limb gravity-balancing exoskeleton uses the spring as an elastic element and the lead screw to adjust the pre-compression of the elastic element, thereby changing the system stiffness of the entire mechanism. When the lower limbs swing, the knee joint binding mechanism transmits force to the gravity-balancing device at the waist through the Bowden cable transmission mechanism. Under force, the sliding plate of the gravity-balancing device begins to slide through the rotation of the gear on the rack and begins to compress the elastic element. The lead screw mechanism changes the system stiffness of the entire mechanism by changing the pre-compression, thereby achieving gravity balance of the lower limbs.

[0018] Furthermore, the gravity balancing device employs a spring-assisted method to counteract the effects of gravity. This spring-assisted method does not add inappropriate weight. By rotating the lead screw to change the pre-compression of the spring, the stiffness of the system is altered, compensating for the gravitational torque generated by the lower limbs during walking. The spring-assisted method utilizes the energy stored in the spring compression to additionally increase elastic potential energy. The human body and the gravity balancing device cooperate to store elastic potential energy, ensuring that the hip joint torque is equal to the leg gravitational torque, thus achieving gravity balance.

[0019] Furthermore, the hip joint torque M h for:

[0020] M h =K h ×(l-l0)×L h

[0021] Among them, K h L is the spring stiffness coefficient, l is the spring length, l0 is the initial spring length, and L h The torque arm of the spring relative to the center of rotation of the hip joint;

[0022] The gravitational torque M of the leg borne by the hip joint during the flexion and elevation of the human lower limb. G for:

[0023] M G =m1gl1 * sinθ h +m2g(l1sinθ h +l2 * sin(θ h -θ k ))+m3g(l1sinθ h +l2sin(θ h -θ k ))

[0024] In this coordinate system, the center of rotation of the hip joint is taken as the origin, l1 is the thigh length, m1 is the thigh mass, and the distance from the center of mass of the thigh to the center of rotation of the hip joint is l1. *l2 is the length of the lower leg, m2 is the mass of the lower leg, and the distance from the center of mass of the lower leg to the center of rotation of the knee joint is l2. * m3 represents the mass of a single point mass at the end of the lower leg, simplified to foot. θ h θ is the rotation angle of the hip joint. k This refers to the angle of rotation of the knee joint;

[0025] According to the static gravity balance model of the human lower limbs, when M g =M h Gravitational torque balance can be achieved at this time, and the stiffness K of the gravity balancing device is... h for:

[0026]

[0027] Among them, θ1, θ2, d3, and h3 can be calculated using the following formulas:

[0028]

[0029]

[0030]

[0031]

[0032] In the formula, d1 is from point U h To P hip The perpendicular distance, d2, is from point U. h To P hip The horizontal distance between them, h1 is from point H to point P. hip The distance, h2 represents the distance from point D. h The distance between point P and H; hip The upper anchor point U is the center of hip joint rotation. h Set at the superior frontal spine, lower anchor point D h Located on the front of the thigh, half the length of the femur, U h D h P hip The plane formed is located in the middle of the thigh and is parallel to the sagittal plane of the human body. Point P is point U. h The projection of point H onto the human torso is point D. h Projection on the midline of the thigh.

[0033] In a preferred embodiment of the present invention, the present invention has the following advantages over the prior art:

[0034] 1. This invention adopts a variable stiffness design, with elastic elements and flexible mechanisms working together to provide appropriate stiffness and shape at different stages to match the changes in human movement, better adapting to the rehabilitation needs of patients. The stiffness can be adjusted according to the actual situation, resulting in higher assistiveness and safety.

[0035] 2. This invention adopts a modular design, with each part being small, simple in structure and easy to assemble. The gravity balance mechanism and Bowden line transmission mechanism are combined, and a biomimetic drive method is used to imitate the force line of the hip flexor muscles of the lower limb, which improves the transmission efficiency and reduces the metabolic cost of the wearer during exercise.

[0036] 3. This invention uses flexible straps instead of rigid connecting rods. Each strap is sewn together and equipped with a fixing buckle for easy wearing and removal. The waist strap serves as the force point of the gravity balance mechanism. The flexible straps fit the human body better and provide a stable force anchor point while ensuring sturdiness. It is more convenient to wear, more comfortable, and can adapt to different body types.

[0037] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0038] Figure 1 This is a schematic diagram illustrating the wearability effect of a preferred embodiment of the present invention;

[0039] Figure 2 This is a schematic diagram of a flexible clothing structure provided in a preferred embodiment of the present invention;

[0040] Figure 3 This is a schematic diagram of a knee joint binding mechanism provided in a preferred embodiment of the present invention;

[0041] Figure 4 This is a schematic diagram of the overall structure of a gravity balancing device provided in a preferred embodiment of the present invention;

[0042] Figure 5 This is a schematic diagram of the internal structure of a gravity balancing device provided in a preferred embodiment of the present invention;

[0043] Figure 6 This is a schematic diagram of the outer side of the sliding plate of the gravity balancing device provided in a preferred embodiment of the present invention;

[0044] Figure 7 This is a schematic diagram of the inner side of the sliding plate of the gravity balancing device provided in a preferred embodiment of the present invention;

[0045] Figure 8 This is a schematic diagram of the sliding assembly structure of the gravity balancing device provided in a preferred embodiment of the present invention;

[0046] Figure 9 This is a schematic diagram of the inner side of the waist fixing shell of the gravity balancing device provided in a preferred embodiment of the present invention;

[0047] Figure 10 This is a mathematical model of the human lower limb hip joint provided in a preferred embodiment of the present invention;

[0048] Figure 11 This is a preferred embodiment of the present invention providing a static gravity balance model of the human lower limbs;

[0049] Figure 12 This is a preferred embodiment of the present invention, which provides a dynamic gravity balance model of the human lower limbs.

[0050] In the picture,

[0051] 1- Flexible garment, 101- Shoulder straps, 102- Chest support strap, 103- Waist support strap, 104- Waist belt.

[0052] 2- Knee joint binding mechanism, 201- Upper knee, 202- Middle knee, 203- Lower knee.

[0053] 3-Bowden wire drive mechanism, 301-Bowden wire,

[0054] 4-Gravity balancing device, 401-Fixed assembly module, 4011-Waist fixed shell, 4012-Guide rod fixing plate, 4013-Sliding fixing piece, 402-Sliding assembly module, 4021-Sliding plate, 40211-Spindle, 40212-Gear, 40213-Gear-spindle shaft, 40214-Gear transmission plate, 4022-Guide rod, 4023-Spring, 4024-Guide pulley, 4025-Screw rod, 4026-Rack, 4027-Pressure hole plate. Detailed Implementation

[0055] The following description, with reference to the accompanying drawings, illustrates several preferred embodiments of the present invention to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0056] In the accompanying drawings, components with the same structure are indicated by the same numerical designation, and components with similar structures or functions are indicated by similar numerical designations. The dimensions and thicknesses of each component shown in the drawings are arbitrary, and the present invention does not limit the dimensions and thicknesses of each component. To make the illustrations clearer, the thickness of some components is appropriately exaggerated in the drawings.

[0057] like Figure 1As shown in the figure, the wearable flexible lower limb gravity-balancing exoskeleton provided by this invention can be used for the rehabilitation of lower limb motor dysfunction. It meets the requirements of being lightweight, highly flexible, and providing more natural assistance. It can compensate for the weight of the hip joint during walking, producing a lower limb gravity balance effect and reducing the wearer's energy consumption during walking. This wearable flexible lower limb gravity-balancing exoskeleton is symmetrical about the human body and includes a flexible garment 1, a knee joint binding mechanism 2, a Bowden cable transmission mechanism 3, and a gravity-balancing device 4.

[0058] The flexible garment 1 is worn on the upper body of the human body, providing force anchor points for the gravity balance device and ensuring the stability of the garment;

[0059] The knee joint binding mechanism 2 is installed at the knee joint of the human lower limb, and the gravity balance device 4 is connected to the knee joint;

[0060] The Bowden wire drive mechanism 3 is located on the front of the thigh to assist hip flexion. The Bowden wire drive mechanism 3 is connected to the knee binding mechanism 2.

[0061] The gravity balance device 4 is installed on the front of the flexible garment 1 to assist in hip flexion. The gravity balance mechanism 4 and the Bowden line transmission mechanism 3 are combined and adopt a biomimetic drive method to imitate the force line direction of the hip flexor muscles of the lower limb.

[0062] like Figure 2 As shown, the flexible garment 1 includes shoulder straps 101, chest fixing straps 102, waist fixing straps 103 and waist belts 104. The shoulder straps 101 are fixedly connected to the chest fixing straps 103, and the waist fixing straps 104 are fixedly connected to the waist belts 104. While providing stable anchor points, the flexible garment 1 is ensured to fit closely to the upper body of the human body.

[0063] Preferably, the shoulder straps 101 are sewn to the chest fixing strap 103, and the waist fixing strap 104 is sewn to the waist belt 104.

[0064] like Figure 3 As shown, the knee joint binding mechanism 2 includes an upper knee 201, a middle knee 202, and a lower knee 203. The upper knee 201 and the lower knee 203 are composed of a low-temperature thermoplastic plate and a sponge liner. The middle knee 202 includes a support spring. The two ends of the middle knee 202 are connected to the low-temperature thermoplastic plates of the upper knee 201 and the lower knee 203, respectively, which improves wearing comfort while ensuring firmness. The upper knee 201 is connected to the lower end of the Bowden wire 301 in the Bowden wire transmission mechanism.

[0065] like Figures 4-9As shown, the gravity balancing device 4 includes a fixed assembly module 401 and a sliding assembly module 402. The fixed assembly module 401 includes a waist fixing shell 4011, a guide rod fixing plate 4012, and a sliding fixing component 4013. The sliding assembly module 402 includes a sliding plate 4021, a guide rod 4022, a spring 4023, a guide pulley 4024, a lead screw 4025, a rack 4026, and a pressure hole plate 4027. The sliding plate 4021 of the sliding assembly module 402 is used to fix the components of the gravity balancing device 4. The sliding plate 4021 fits into the holes on both sides of the waist fixing shell 4011. The sliding fixing component 4013 and the guide pulley 4024 are the same in number, and the number of each is set to three. The guide pulley 2024 is fixed to the outside of the sliding plate 4021 by bolts via the sliding fixing member 4013, and is used to define the transmission path for the Bowden line 301. The gear transmission plate 40214 is embedded in the upper part of the sliding plate 4021, and is used to fix the inner mechanism. The gear spool shaft 40213 on the inner side of the sliding plate 4021 connects two gears 40212 and one spool 40211 to the gear transmission plate 40214, and is used to tighten or extend the Bowden line 301 during driving. The upper end of the guide rod 4022 is connected to the guide rod fixing plate 4012 by bolts. The pressure plate 4027 is provided with three holes, through which two guide rods 4022 and a lead screw 4025 pass respectively. Two springs 4023 are respectively sleeved on the two guide rods 4022, and are used to define the compression path for the springs 4023. The two racks 4026 fixed inside the waist fixing shell 4011 are used to mesh with the gear 40212. When the spring 4023 is compressed or relaxed, the rotation of the gear 40212 drives the sliding plate 4021 to slide up and down.

[0066] The wearable flexible lower limb gravity-balancing exoskeleton uses a spring 4023 as an elastic element and a lead screw 4025 to adjust the pre-compression of the elastic element, thereby changing the system stiffness of the entire mechanism. When the lower limbs swing, the knee joint binding mechanism 2 transmits the force to the gravity balancing device 4 at the waist through the Bowden wire 301 transmission mechanism. Under the force, the sliding plate 4021 of the gravity balancing device 4 begins to slide through the rotation of the gear 40212 on the rack 4026 and begins to compress the elastic element. The lead screw mechanism changes the system stiffness of the entire mechanism by changing the pre-compression, thereby achieving the effect of lower limb gravity balance.

[0067] The gravity balancing device 4 employs a spring-assisted method to counteract the effects of gravity. This method avoids adding undue weight and alters the system's stiffness by rotating the lead screw 4025 to change the pre-compression of the spring 4023, thus compensating for the gravitational torque generated by the lower limbs during walking. The spring-assisted method utilizes the energy stored in the spring 4023 during compression, additionally increasing elastic potential energy. The human body and the gravity balancing device 4 work together, storing elastic potential energy to ensure that the hip joint torque equals the leg's gravitational torque, achieving a gravitational balance.

[0068] Hip joint torque M h for:

[0069] M h =K h ×(l-l0)×L h

[0070] Among them, K h L is the spring stiffness coefficient, l is the spring length, l0 is the initial spring length, and L h The torque arm of the spring relative to the center of rotation of the hip joint;

[0071] The gravitational torque M of the leg borne by the hip joint during the flexion and elevation of the human lower limb. G for:

[0072] M G =m1gl1 * sinθ h +m2g(l1sinθ h +l2*sin(θ h -θ k ))+m3g(l1sinθ h +l2sin(θ h -θ k ))

[0073] In this coordinate system, the center of rotation of the hip joint is taken as the origin, l1 is the thigh length, m1 is the thigh mass, and the distance from the center of mass of the thigh to the center of rotation of the hip joint is l1. * l2 is the length of the lower leg, m2 is the mass of the lower leg, and the distance from the center of mass of the lower leg to the center of rotation of the knee joint is l2. * m3 represents the mass of a single point mass at the end of the lower leg, simplified to foot. θ h θ is the rotation angle of the hip joint. k This refers to the angle of rotation of the knee joint;

[0074] According to the static gravity balance model of the human lower limbs, when M g =M h Gravitational torque balance can be achieved at this time, and the stiffness K of the gravity balancing device is... h for:

[0075]

[0076] Among them, θ1, θ2, d3, and h3 can be calculated using the following formulas:

[0077]

[0078]

[0079]

[0080]

[0081] In the formula, d1 is from point U h To P hip The perpendicular distance, d2, is from point U. h To P hip The horizontal distance between them, h1 is from point H to point P. hip The distance, h2 represents the distance from point D. h The distance between point P and H; hip The upper anchor point U is the center of hip joint rotation. h Set at the superior frontal spine, lower anchor point D h Located on the front of the thigh, half the length of the femur, U h D h P hip The plane formed is located in the middle of the thigh and is parallel to the sagittal plane of the human body. Point P is point U. h The projection of point H onto the human torso is point D. h The projection on the midline of the thigh, such as Figure 10 As shown.

[0082] This invention addresses the problem that the rigid structure of traditional exoskeletons is difficult to adapt to the changing movement of the human body at different stages and to complex external environments. This invention employs a variable stiffness design, combining elastic elements and flexible mechanisms to provide appropriate stiffness and shape at different stages to match the body's movement changes, better meeting the rehabilitation needs of patients. Adjusting stiffness according to actual conditions enhances safety. The wearable flexible lower limb gravity-balancing exoskeleton provided by this invention features a line-driven mechanism to assist in lower limb flexion. The principle of the lower limb gravity-balancing mechanism applied to the hip joint is implemented through springs, gears, and rope drives. A kinematic and dynamic model of the human lower limb is established, analyzing and solving the torque magnitudes at each joint under gravity-balancing assistance during gait, deriving a gravity-balancing model consistent with human lower limb walking, enabling gravity balance during walking. This invention uses rigorous theoretical calculations to accurately simulate human dynamics and kinematic factors, helping to optimize the exoskeleton structure, resulting in a higher degree of adaptation between the exoskeleton and the human body, improving the exoskeleton's assistive capabilities and safety.

[0083] Furthermore, addressing the issue of existing exoskeleton structures being large and heavy, increasing the wearer's energy consumption as an additional burden, this invention adopts a modular design with smaller parts, a simpler structure, and convenient assembly. The gravity balance mechanism and Bowden cable transmission mechanism are combined, employing a biomimetic drive method that mimics the force line of the hip flexors in the lower limbs, improving transmission efficiency and reducing the wearer's metabolic costs during exercise. The gravity balance device provided in this embodiment mainly comprises a sliding module and a fixed module. The device is fixed to the waist strap via the fixed module. Internally, gears and racks work together to slide the sliding plate. The upper end of the Bowden cable transmission mechanism connects to the internal gears, and the lower end connects to the upper part of the knee joint binding mechanism. When the lower limbs swing, the knee joint binding mechanism transmits force to the gravity balance device in the waist via the Bowden cable transmission mechanism. Under force, the sliding plate begins to slide through the rotation of the gears on the rack, compressing the elastic element. At this time, the lead screw mechanism can change the system stiffness of the entire mechanism by altering the pre-compression, achieving the effect of lower limb gravity balance. Meanwhile, the gravity balancing device provided in this embodiment of the invention has small mass and size, simple module structure, and low cost.

[0084] Addressing the issue that existing exoskeletons are mostly rigid structures that do not conform well to the human body, have poor wearing comfort, and may affect the wearer's normal gait, this invention uses flexible straps instead of rigid links. Each strap is sewn together and equipped with a fixing buckle for easy putting on and taking off. The waist straps serve as the force-bearing point of the gravity balance mechanism. The flexible garment distributes the force evenly to the upper body through the force-bearing point of the waist straps. The knee joint binding mechanism is divided into upper, middle, and lower parts to better fix the force-bearing points of the lower limbs and protect the knee joint. The mechanism will not shift under the action of force. The flexible straps conform more closely to the human body, providing stable force anchor points while ensuring sturdiness. It is easier to wear, more comfortable, and can adapt to different body types.

[0085] The present invention will now be described in detail with reference to preferred embodiments.

[0086] A preferred embodiment of the present invention provides a wearable flexible lower limb gravity-balancing exoskeleton, comprising a flexible garment 1, a knee joint binding mechanism 2, a Bowden cable transmission mechanism 3, and a gravity-balancing device 4, the wearing effect of which is as follows: Figure 1 As shown.

[0087] The flexible garment 1 is worn on the upper body, providing a force anchor point for the gravity balancing device 4 and ensuring stability. The knee joint binding mechanism 2 is installed at the knee joint of the lower limbs to connect the gravity balancing device 4 to the knee joint. The Bowden cable transmission mechanism 3 is distributed on the front of the thigh, providing assistance for hip flexion. The gravity balancing device 4 is installed on the front of the flexible garment 1 to assist hip flexion. This invention provides auxiliary torque for hip flexion under different phases of the wearer's hip joint, and achieves lower limb gravity balance by changing the spring stiffness to compensate for the gravity of the hip joint, thereby improving the walking stability of people with lower limb dysfunction and improving abnormal gait.

[0088] The wearable flexible lower limb gravity-balanced exoskeleton of this embodiment is symmetrical about the left and right sides of the human body. Unless otherwise specified, only the structure on one side will be described below.

[0089] like Figure 2 As shown, the flexible garment 1 includes shoulder straps 101, a chest fixing strap 102, a waist fixing strap 103, and a waist belt 104. The shoulder straps 101 are sewn to the chest fixing strap 102, and the waist fixing strap 103 is sewn to the waist belt 104. This provides stable anchor points while ensuring that the flexible garment 1 fits closely to the upper body of the human body.

[0090] like Figure 3 As shown, the knee joint binding mechanism 2 includes an upper knee section 201, a middle knee section 202, and a lower knee section 203. Both the upper knee section 201 and the lower knee section 203 are composed of a low-temperature thermoplastic plate and a sponge lining. The middle knee section 202 includes a support spring, with both ends connected to the low-temperature thermoplastic plates of the upper knee section 202 and the lower knee section 203, respectively, ensuring both stability and improved wearing comfort. The lower end of the Bowden cable 301 is connected to the upper knee section 201.

[0091] like Figure 4 and 5 As shown, the various parts of the fixed assembly module 401 and the sliding assembly module 402 are connected. The main parts are fixed on the sliding plate 4021. The sliding plate 4021 fits into the holes on both sides of the waist fixed shell 4011 to form the entire gravity balancing device 4.

[0092] like Figure 6 and 7 As shown, three guide pulleys 4024 are bolted to the outside of the sliding plate 4021 by three sets of sliding fasteners 4013, defining the transmission path for the Bowden line 301. The gear transmission plate 40214 is embedded in the upper part of the sliding plate 4021, fixing the inner mechanism. The gear-spool shaft 40213 inside the sliding plate 4021 connects two gears 40212 and one spool 40211 to the gear transmission plate 40214, used to tighten or extend the Bowden line during operation.

[0093] like Figure 8 As shown, the upper end of the guide rod 4022 is connected to the guide rod fixing plate 4012 by bolts. The pressure plate 4026 has three holes, through which two guide rods 4022 and a lead screw 4025 pass respectively. Two springs 4023 are respectively fitted on the two guide rods 4022 to specify the compression path of the springs 4023.

[0094] like Figure 9 As shown, the two racks 4026 fixed inside the waist fixing shell 4011 are used to mesh with the gear 40212. When the spring is compressed or relaxed, the rotation of the gear 40212 drives the sliding plate 4021 to slide up and down.

[0095] The gravity balancing device uses a spring-assisted method to utilize the energy stored in the spring compression to counteract the effect of gravity. Furthermore, the spring-assisted method does not add any undue weight to the system. The system's stiffness is changed by rotating the lead screw to alter the spring's pre-compression, thus compensating for the gravitational torque generated by the lower limbs during walking.

[0096] During walking, the lower limbs convert kinetic and potential energy to conserve metabolic energy, while the gravity balance device adds extra elastic potential energy. From standing to extending the legs backward, the movement of the lower limbs stores energy in the springs, reaching its maximum elastic potential energy at the maximum angle. As the legs swing forward, the gravitational potential energy gradually decreases to zero, and some of the stored elastic potential energy is converted into kinetic energy. During the flexion and lifting of the swinging leg, the spring stiffness in the gravity balance device increases, and at the highest flexion position, all the stored elastic and kinetic energy is converted into gravitational potential energy. Throughout the walking process, the human body and the device work together, storing elastic potential energy to ensure that the hip joint torque equals the leg's gravitational torque, thus achieving gravitational balance.

[0097] For mathematical models of hip exoskeletons, such as Figure 10 As shown, K h Consider it as the stiffness coefficient of a spring, where l is the length of the spring, l0 is the initial length of the spring, and L h Let M be the torque arm of the spring relative to the center of rotation of the hip joint, then the torque M generated by the hip joint... h for

[0098] M h =K h ×(l-l0)×L h

[0099] For a static gravity balance model of the human lower limbs, the legs are considered as... Figure 11 The two-degree-of-freedom mechanism shown has the hip joint rotation center as the origin, the thigh length as l1, the mass as m1, and the distance from the center of mass to the hip joint rotation center as l1. *Let the length of the lower leg be l2, its mass be m2, and the distance from the center of mass to the center of rotation of the knee joint be l2. * Simplifying the foot to a point of mass m3 at the end of the lower leg, neglecting the ankle joint, and considering only the rotation angles of the hip and knee joints, the gravitational torque M borne by the hip joint during the flexion and elevation of the lower limb is then calculated. G for:

[0100] M G =m1gl1 * sinθ h +m2g(l1sinθ h +l2 * sin(θ h -θ k ))+m3g(l1sinθ h +l2sin(θ h -θ k ))

[0101] Let M g =M h Gravitational torque balance can be achieved, and the stiffness of the gravity-balanced system is K. h :

[0102]

[0103] Among them, θ1, θ2, d3, and h3 can be calculated using the following formulas:

[0104]

[0105]

[0106]

[0107]

[0108] In the formula, d1 is from point U h To P hip The perpendicular distance, d2, is from point U. h To P hip The horizontal distance between them, h1 is from point H to point P. hip The distance, h2 represents the distance from point D. h The distance between point P and H; hip The upper anchor point U is the center of hip joint rotation. h Set at the superior frontal spine, lower anchor point D h Located on the front of the thigh, half the length of the femur, U h D h P hip The plane formed is located in the middle of the thigh and is parallel to the sagittal plane of the human body. Point P is point U.h The projection of point H onto the human torso is point D. h The projection on the midline of the thigh, such as Figure 10 As shown.

[0109] For the dynamic gravity balance model of the human lower limbs, such as Figure 12 As shown, the potential energy and kinetic energy of the human lower limbs are mutually converted, thereby saving the body's energy consumption. When a spring is added to the lower limb system, elastic potential energy is added to the potential energy.

[0110] Taking the center of hip joint rotation as the zero potential energy position, during the swing leg movement, assuming the human joint does no more work, the swing begins at position a, where the elastic potential energy is at its maximum, the gravitational potential energy is the initial value of hip flexion during the swing, and the kinetic energy is zero. When the leg reaches position b, assuming the gravitational potential energy is 0, the kinetic energy reaches its maximum, and part of the elastic potential energy is converted into kinetic energy. When the leg reaches position c, the gravitational potential energy reaches its maximum, the elastic potential energy is zero, and the kinetic energy is also zero. Therefore, at this moment, all elastic potential energy and kinetic energy are converted into gravitational potential energy. The swing leg flexes and rises to its highest position, which is equivalent to the maximum elastic potential energy of the auxiliary spring being equal to the change in gravitational potential energy from position c to position a.

[0111] The working principle of the wearable flexible lower limb gravity-balancing exoskeleton of the present invention is as follows:

[0112] The entire mechanism uses a spring 4023 as the elastic element and a lead screw 4025 to adjust the pre-compression of the elastic element, thereby changing the system stiffness of the entire mechanism. When the lower limbs swing, the knee joint binding mechanism 2 transmits force to the gravity balancing device 1 at the waist through the Bowden cable transmission mechanism 3. Under the force, the sliding plate 4021 of the device begins to slide through the rotation of the gear 40212 on the rack 4026 and begins to compress the elastic element. At this time, the lead screw mechanism can change the system stiffness of the entire mechanism by changing the pre-compression, thereby achieving the effect of lower limb gravity balance.

[0113] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A wearable flexible lower limb gravity-balancing exoskeleton, characterized in that, The wearable flexible lower limb gravity-balancing exoskeleton is symmetrical about the human body and includes flexible clothing, a knee joint binding mechanism, a Bowden cable transmission mechanism, and a gravity-balancing device. The flexible garment is worn on the upper body and provides force anchor points for the gravity balance device, ensuring the stability of the garment. The knee joint binding mechanism is installed at the knee joint of the human lower limb and connects the gravity balance device to the knee joint. The knee joint binding mechanism includes an upper part of the knee, a middle part of the knee, and a lower part of the knee. The Bowden cable drive mechanism is located on the front of the thigh and provides assistance for hip flexion. The Bowden cable drive mechanism is connected to the knee joint binding mechanism. The gravity balancing device is installed on the front of the flexible garment to assist hip joint flexion. The gravity balancing device and the Bowden line transmission mechanism are combined and adopt a biomimetic drive method to mimic the force line direction of the hip flexor muscles of the lower limb. in, The gravity balancing device includes a fixed group module and a sliding group module. The gravity balancing device is fixed to the waist strap through the fixed group module. The gravity balancing device uses gears and racks to slide the sliding plate. The upper end of the Bowden cable transmission mechanism is connected to the gear inside the device, and the lower end is connected to the upper part of the knee joint binding mechanism. The fixed assembly module includes a waist fixing shell, a guide rod fixing plate, and a sliding fixing component. The sliding assembly module includes a sliding plate, a guide rod, a spring, a guide pulley, a lead screw, a rack, and a pressure hole plate. The sliding plate of the sliding assembly module is used to fix the components of the gravity balancing device. The sliding plate is fitted with the holes on both sides of the waist fixing shell. The guide pulley is fixed to the outside of the sliding plate by the sliding fastener via bolts, and is used to define the transmission path for the Bowden line; the gear transmission plate is embedded in the upper part of the sliding plate, and is used to fix the inner mechanism; the gear and spool shaft on the inner side of the sliding plate connects the two gears and one spool to the gear transmission plate, and is used to tighten or extend the Bowden line during driving; The two racks fixed inside the waist fixing shell are used to mesh with the gear, and when the spring is compressed or relaxed, the rotation of the gear drives the sliding plate to slide up and down; The wearable flexible lower limb gravity-balancing exoskeleton uses springs as elastic elements and a lead screw to adjust the pre-compression of the elastic elements, thereby changing the system stiffness of the entire mechanism. When the lower limbs swing, the knee joint binding mechanism transmits force to the gravity-balancing device at the waist through the Bowden cable transmission mechanism. Under force, the sliding plate of the gravity-balancing device begins to slide through the rotation of the gear on the rack and begins to compress the elastic element. The lead screw mechanism changes the system stiffness of the entire mechanism by changing the pre-compression, thereby achieving gravity balance of the lower limbs.

2. The wearable flexible lower limb gravity-balancing exoskeleton as described in claim 1, characterized in that, The flexible garment includes shoulder straps, a chest fixing strap, a waist fixing strap, and a waist belt. The shoulder straps are fixedly connected to the chest fixing strap, and the waist fixing strap is fixedly connected to the waist belt, providing stable anchor points while ensuring that the flexible garment fits closely to the upper body.

3. The wearable flexible lower limb gravity-balancing exoskeleton as described in claim 1, characterized in that, The upper and lower parts of the knee are composed of a low-temperature thermoplastic plate and a sponge liner. The middle part of the knee includes a support spring. The two ends of the middle part of the knee are respectively connected to the low-temperature thermoplastic plate of the upper and lower parts of the knee, which improves wearing comfort while ensuring firmness. The upper part of the knee is connected to the lower end of the Bowden wire in the Bowden wire transmission mechanism.

4. The wearable flexible lower limb gravity-balancing exoskeleton as described in claim 1, characterized in that, The number of sliding fasteners and guide pulleys is the same, and the number of each is set to three sets.

5. The wearable flexible lower limb gravity-balancing exoskeleton as described in claim 4, characterized in that, The upper end of the guide rod is connected to the guide rod fixing plate by bolts. The pressure plate has three holes through which two guide rods and one lead screw pass. Two springs are respectively fitted on the two guide rods to define the compression path of the springs.

6. The wearable flexible lower limb gravity-balancing exoskeleton as described in claim 5, characterized in that, The gravity balancing device uses a spring-assisted method to counteract the effects of gravity. This spring-assisted method does not add inappropriate weight. By rotating the lead screw, the pre-compression of the spring is changed to alter the stiffness of the system, compensating for the gravitational torque generated by the lower limbs during walking. The spring-assisted method utilizes the energy stored in the spring compression to additionally increase elastic potential energy. The human body and the gravity balancing device cooperate to store elastic potential energy, ensuring that the hip joint torque is equal to the leg gravitational torque, thus achieving gravity balance.

7. The wearable flexible lower limb gravity-balancing exoskeleton as described in claim 6, characterized in that, The hip joint torque for: in, This is the spring stiffness coefficient. The length of the spring. The initial length of the spring. The torque arm of the spring relative to the center of rotation of the hip joint; The gravitational torque on the hip joint during the flexion and elevation of the human lower limb. for: With the center of hip joint rotation as the origin of the coordinate system, Thigh length The mass of the thigh is [value], and the distance from the center of mass of the thigh to the center of rotation of the hip joint is [value]. , Calf length, Let be the mass of the lower leg, and the distance from the center of mass of the lower leg to the center of rotation of the knee joint be . , The foot is simplified to the mass of a single point of mass at the end of the lower leg. This refers to the rotation angle of the hip joint. This refers to the angle of rotation of the knee joint; According to the static gravity balance model of the human lower limbs, when Gravitational torque balance can be achieved at this time, and the stiffness of the gravity balancing device is... for: in, , , , It can be calculated using the following formula: In the formula, From point arrive vertical distance, From point arrive The horizontal distance between them From point Time distance, Point and Distance between; points The upper anchor point is the center of hip joint rotation. Set at the superior frontal spine, lower anchor point Located on the front of the thigh, at half the length of the femur, on the body surface. The plane formed is located in the middle of the thigh and is parallel to the sagittal plane of the human body. It is a point The projection on the human torso, point It is a point Projection on the midline of the thigh.

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