Active lower limb four-link heterogeneous exoskeleton and use method thereof

Abstract

The present invention discloses an active lower limb four-bar linkage heterogeneous exoskeleton and a method of using the same, comprising a back plate, a hip joint, a four-bar linkage knee joint, a shank rod, and a sole shoe cover; the back plate is connected to the hip joint shaft hole through a hip joint position shaft; the hip joint and the four-bar linkage knee joint are connected to the bolts of a motor through a bracket; the four-bar linkage knee joint is connected to the shank rod through a shaft hole; the shank rod is connected to the sole shoe cover through a fisheye bearing; the sole shoe cover is at the end of the exoskeleton, and the hip joint, the four-bar linkage knee joint, the shank rod, and the sole shoe cover are mirror-mounted with the back plate as a reference plane. The active lower limb four-bar linkage heterogeneous exoskeleton provided by the present invention reduces the swing inertia of the lower limb joints and components through the coaxial layout of the hip and knee motors, and the knee joint four-bar linkage drive form amplifies the torque on the knee joint shaft, thereby improving the support capacity of the exoskeleton joint.

Description

Technical Field

[0001] The present invention belongs to the technical field of wearable lower limb exoskeletons, and in particular relates to an active lower limb four-link heterogeneous exoskeleton and a method of using the same. Background Art

[0002] At present, lower limb exoskeleton robots are developing rapidly in the military and health care fields in the direction of human capacity enhancement and lower limb rehabilitation for sick and elderly patients. The application scenarios are constantly expanding, and exoskeletons are gradually beginning to show their advantages.

[0003] At present, the hip joint design of mainstream lower limb exoskeletons generally simulates and corresponds to the rotational freedom of human joints to design exoskeletons in a bionic manner. The isomorphic form of exoskeletons fits the human body, but there are problems such as large motion inertia and high control difficulty; therefore, heterogeneous exoskeletons that do not correspond to the freedom of human joints are gradually appearing in people's vision. The main advantages of heterogeneous exoskeletons are high wearing comfort, non-fitting to the human body, and large freedom of movement. The difficulty of terrain recognition and posture control is lower than that of isomorphic exoskeletons.

[0004] However, the technical problems are: 1) The lower limbs of the exoskeleton are too heavy, and the large inertia causes inconvenience in lower limb movement and large interaction force; 2) When the heterogeneous exoskeleton extends the leg, the leg length cannot be adjusted, which interferes with the human kicking action and restricts the wearer's movement behavior; 3) The heterogeneous exoskeleton has an infinite position structure, which makes it impossible for the motor to determine a unified zero position during static support; 4) The lower limb structure has no gravity compensation device, and the exoskeleton's own gravity is not conducive to interactive control between humans and machines; 5) The existing motor torque does not match the knee joint movement torque. Summary of the invention

[0005] The purpose of the present invention is to provide an active lower limb four-link heterogeneous exoskeleton and a method of using the same, which is a heterogeneous exoskeleton that does not interfere with human body movements, is highly comfortable to wear, does not fit the human body, and has a large degree of freedom of movement.

[0006] In order to achieve the purpose of the present invention, on the one hand, the present invention provides an active lower limb four-bar heterogeneous exoskeleton, including a back plate, a hip joint, a four-bar knee joint, a calf rod, and a plantar shoe cover; the back plate is connected to the hip joint shaft hole through a hip joint position shaft; the hip joint and the four-bar knee joint are connected through a bracket and a bolt of a motor; the four-bar knee joint is connected to the calf rod through a shaft hole; the calf rod is connected to the plantar shoe cover through a fisheye bearing; the plantar shoe cover is at the end of the exoskeleton and is a base for the back plate, the hip joint, the four-bar knee joint, and the calf rod.

[0007] The back panel includes a plastic shell, a carbon plate, a lithium battery, a battery sheet metal fixing frame, a support plate support shaft, a square structure carbon tube, a waist plate structural frame, a support plate carbon tube, and a support plate; the plastic shell and the carbon plate are connected by copper nuts and bolts on the screw columns, and the carbon plate and the square structure carbon tube are connected to each other by riveting; the lithium battery is installed between two of the square structure carbon tubes, and is connected by bolts between the battery sheet metal fixing frame and the rivet nuts on the carbon plate, and the battery sheet metal fixing frame is connected to the carbon plate and the square structure carbon tube by bolts; the support plate support shaft is connected to the waist plate structural frame bolts by semicircular hole structure positioning, and the waist plate structural frame is connected to the square structure carbon tube by square slot hole positioning and bolt tightening, and the support plate support shaft is installed on the waist plate structural frame; the support plate carbon tube is connected to the support plate support shaft by a rotating shaft, and the support plate is covered on its outside, and the support plate is used for the external connection device of the back panel to support heavy objects.

[0008] The hip joint includes a back connecting plate, a plastic sleeve, a hip abduction shaft, a hip abduction frame, an external rotation shaft, a hip motor, a ball joint nut, a hip motor bracket, a ball joint, a hip motor output rod, a hip thigh rod, a rod-shaped elastic element, an external rotation shaft locking screw, a gasket, and an abduction shaft screw; the back connecting plate is connected to the bolt of the hip abduction shaft through the gasket and the abduction shaft screw; the plastic sleeve is assembled on the two end surfaces of the shaft hole of the hip abduction frame, the flange surface of the plastic sleeve is tightly mounted on the surface of the hip abduction frame, and the hip abduction shaft is connected to the abduction shaft through the abduction shaft screw The thread is fixedly connected in the positioning groove of the back connecting plate, and the hip abduction frame and the hip abduction shaft form a revolving pair under the lubrication of the plastic sleeve; the external rotation shaft is inserted and installed on the concentric axial holes on both sides of the hip abduction frame, and the positioning is formed by the surface contact between the boss on one side of the external rotation shaft and the countersunk hole of the hip abduction frame, and the external rotation shaft locking screw is threadedly connected with the internal thread on the other side of the external rotation shaft to fasten the external rotation shaft in the axial hole of the hip abduction frame to form a revolving pair; the hip joint motor is connected to the hip joint motor bracket through the threaded hole on the surface; the ball hinge joint nut is connected to the ball The hinged head is fixed to the hip joint motor bracket by threaded connection, and the hip joint motor bracket forms a rotation pair with the hip joint abduction frame under the support of the external rotation axis; the ball hinge joint is connected to the rod-shaped elastic element by a ball hinge; the hip joint motor output rod is connected to the hip joint motor by fastening with the pin positioning matching bolts on the output end face of the hip joint motor; the hip joint thigh rod is connected to the hip joint motor output rod by fastening with the axial hole matching bolts; both ends of the rod-shaped elastic element are connected to the ball hinge joint, and one end of the ball hinge joint is fixed to the back connecting plate and the other end is fixed to the hip joint motor bracket The external rotation axis locking screw is connected to the external rotation axis lock; the gasket is fastened between the back connecting plate and the abduction axis screw, the back connecting plate is connected to the hip abduction axis through the gasket and the abduction axis screw, and the hip abduction frame and the hip abduction axis form a rotation pair; the hip joint motor is fixed to the hip joint motor bracket by screws, and the hip joint motor output rod is fixed to the output end of the hip joint motor, extending downward and connected to the hip joint thigh rod through a thread; the hip joint motor bracket and the hip abduction frame are connected through the external rotation axis to form a rotation pair.

[0009] The four-bar linkage knee joint includes a knee joint motor, a knee joint motor bracket, a hip joint thigh rod, a knee joint bearing seat, a calf connecting rod, a gas spring, a gas spring connecting rod, a fisheye joint, a motor output rod, an extension limit PU pad, and a flexion limit PU pad; the knee joint motor is connected to the threaded hole of the knee joint motor bracket by a bolt, the knee joint motor bracket is threadedly connected to the hip joint thigh rod, the hip joint thigh rod is fastened with a bolt to the axial hole of the knee joint bearing seat, the knee joint bearing seat is connected to the calf connecting rod by a bearing support through a plug screw, and the calf connecting rod is connected to the The gas spring is connected through a fisheye bearing, the gas spring is connected to the gas spring connecting rod through a screw, the gas spring connecting rod is connected to the motor output rod through the fisheye joint, and the motor output rod is connected to the knee joint motor through an axial hole and bolt fastening; the extension limit PU pad and the flexion limit PU pad are respectively fixed on the two side positions of the step surface of the knee joint motor bracket, and the shapes of the extension limit PU pad and the flexion limit PU pad correspond to the side of the motor output rod, respectively serving as the limit points for the knee joint to extend and flex to the limit, protecting the human body from being affected by the loss of control of the exoskeleton.

[0010] The calf rod includes a leg length extension structure, a leg length adjustment mechanism, and a force sensor; the leg length extension structure is connected to the leg length adjustment mechanism via axial hole matching circumferential bolts, the leg length adjustment mechanism is connected to the force sensor via end face positioning circumferential bolts, and the force sensor is connected to the four-bar knee joint structure bolts.

[0011] The leg extension structure includes a foot connector, a buffer TPU pad, an inner extension tube, a first spring pin, a tension spring, a second spring pin, a sliding membrane, and an outer tube; the foot connector is connected to the inner extension tube through the first spring pin through a pin-controlled fit; the buffer TPU pad is placed between the foot connector and the outer tube; the inner extension tube is fixed to the foot connector through a spring pin, the first spring pin is inserted into the pin holes of the foot connector and the inner extension tube through an interference fit, the tension spring is connected between the first spring pin and the second spring pin through a pull ring, and the second spring pin is fixed in the pin hole of the outer tube through an interference fit; the sliding membrane is matched with the slot inside the outer tube through a convex point, and the outer tube serves as the end of the mechanism, and its bottom surface is in contact with the buffer TPU pad.

[0012] The leg length adjustment mechanism includes a friction locking rear opening, a locking sleeve, a friction locking front opening, a carbon fiber inner tube, a positioning pin, and a carbon fiber outer tube; the friction locking rear opening is connected to the friction locking front opening via a tapered thread, and the friction locking front opening is glued to the end of the carbon fiber outer tube; the locking sleeve is clamped on the outside of the carbon fiber inner tube, and the carbon fiber inner tube and the positioning pin are interference fit through a through hole on the tube surface, and a compression head is provided on the head of the positioning pin, and the axial position of the carbon fiber inner tube on the carbon fiber outer tube is adjusted by pressing, and the carbon fiber outer tube is provided with an outer tube hole, which cooperates with the positioning pin compression head for positioning.

[0013] The sole shoe cover includes a silicone rubber shoe cover, a foot fisheye bearing, and a foot support; the silicone rubber shoe cover is connected to the foot support through side bolts; the foot fisheye bearing is constrained by the foot support pin through a bearing hole, and the foot support is located on the side of the mechanism, and is used to transmit the load force of the lower limbs to the ground through the foot fisheye bearing.

[0014] On the other hand, the present invention also provides a method for using an active lower limb four-link heterogeneous exoskeleton, comprising the following steps:

[0015] Step 1: After the exoskeleton is powered on, the system is initialized and the IMU and motor encoder located on the human calf are calibrated to zero.

[0016] Step 2: When the person wearing the exoskeleton exercises, the posture sensor IMU monitors the human motion characteristics in real time, processes the movement speed of the human lower limbs, builds a human motion estimation model based on the human calf angle combined with the human gait characteristics, and builds a human-exoskeleton motion mapping model based on the human motion trajectory model combined with the exoskeleton related rod information, quantifies the human joint motion and maps it to the exoskeleton joint angle, and compares the angular velocities of the left and right calves of the human body. The exoskeleton joint corresponding to the side with lower angular velocity is multiplied by an attenuation function to reduce the interference with the human body during high-speed movement, so as to achieve a multi-terrain tracking effect, so that the exoskeleton controller drives the hip joint motor and the knee joint motor to output torque;

[0017] Step 3: The hip joint motor drives the knee joint motor bracket to rotate, and the thigh is extended through binding. The knee joint motor drives the knee joint motor output rod to rotate, and promotes the four-bar linkage to rotate in space, driving the calf connecting rod to rotate around the knee joint bearing seat, and the calf is extended through binding;

[0018] Step 4: Gait swing phase: In the leg extension structure, the human leg drives the extension spring fixed at the foot joint to extend, providing freedom for kicking, and rebounding to provide assistance at the beginning of the gait support phase;

[0019] Step 5: Gait support phase: the hip joint motor is stalled, the hip joint motor and the knee joint motor bracket remain relatively still to provide a support torque; the knee joint motor is stalled, the knee joint motor output rod and the knee joint motor remain relatively still to provide a support torque;

[0020] Step 6: The left and right legs output torque alternately, following the movement of the human body and supporting the human joints, and the program starts to run normally.

[0021] Compared with the prior art, the significant progress of the present invention lies in: (1) The present invention adopts a heterogeneous layout of the hip joint, knee joint and human body, and transfers the mass of the motor and other components to the hip part of the exoskeleton by adopting a coaxial arrangement of the hip and knee motors. The lower limbs are only the mass of the leg rod and other devices, which greatly reduces the leg swing inertia and improves the wearing comfort and portability of movement. (2) The present invention designs a leg movement spring extension compensation mechanism to ensure that the calf is not restricted from movement due to structural interference during the swing process. (3) The present invention arranges an elastic PU pad on the motor bracket to limit the movement of the motor while absorbing shock and noise. (4) The present invention adopts a three-degree-of-freedom passive anthropomorphic degree-of-freedom design of the hip joint. Through the self-weight compensation structure of the hip joint, the characteristics of the anthropomorphic three-degree-of-freedom are ensured, while ensuring that the abduction / adduction and external rotation / internal rotation degrees of freedom of the hip joint are not restricted. (5) The present invention amplifies the motor output torque through a four-bar linkage mechanism and applies it to the knee joint to match the torque change during the joint movement.

[0022] In order to more clearly illustrate the functional characteristics and structural parameters of the present invention, further description is given below in conjunction with the accompanying drawings and specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0024] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0025] Figure 2 is an exploded schematic diagram of the back plate structure of the present invention;

[0026] Figure 3 is an exploded schematic diagram of the hip joint structure of the present invention;

[0027] Figure 4 is an axial schematic diagram of the four-bar linkage knee joint structure of the present invention;

[0028] Figure 5 is a front view schematic diagram of the four-bar linkage knee joint structure of the present invention;

[0029] Figure 6It is a schematic diagram of the components of the calf rod of the present invention;

[0030] Figure 7 is an exploded schematic diagram of the calf rod of the present invention;

[0031] Figure 8 is a schematic diagram of a foot shoe cover structure of the present invention;

[0032] Fig. 9 It is a process flow of active lower limb four-link heterogeneous exoskeleton driving method.

[0033] The reference numerals in the figure are: 1, back plate; 2, hip joint; 3, four-link knee joint; 4, calf rod; 5, sole shoe cover; 101, plastic shell; 102, carbon plate; 103, lithium battery; 104, battery sheet metal fixing frame; 105, support plate support shaft; 106, square structure carbon tube; 107, waist plate structure frame; 108, support plate carbon tube; 109, support plate; 201, back connecting plate; 202, plastic shaft sleeve; 203, hip abduction axis; 204, hip abduction frame; 205, external rotation axis; 206, hip motor; 207, ball joint nut; 208, hip motor; 209, bracket ball joint; 210, hip motor output rod; 211, hip thigh rod; 212, rod-shaped elastic element; 213, external rotation axis; 214, locking screw gasket; 215, abduction axis screw; 301, knee motor; 302, knee motor bracket; 303, knee bearing seat; 304, calf connecting rod; 305, gas spring; 306, gas spring connecting rod; 307, fisheye joint; 308, motor output rod; 309, extension limit PU pad; 310, flexion limit PU pad; 401, leg length extension structure; 402, leg length adjustment mechanism; 403, force sensor; 411, foot connector; 412, buffer TPU pad; 413, inner extension tube; 414, first spring pin; 415, tension spring; 416, second spring pin; 417, sliding membrane; 418, outer tube; 421, friction locking rear opening; 422, locking sleeve; 423, friction locking front opening; 424, carbon fiber inner tube; 425, positioning pin; 426, carbon fiber outer tube; 501, silicone rubber shoe cover; 502, foot fisheye bearing; 503, foot support. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0035] The present invention is an active lower limb four-link heterogeneous exoskeleton, combined with Figure 1 , including a back plate 1, a hip joint 2, a four-bar knee joint 3, a calf rod 4, and a sole shoe cover 5; the back plate 1 is used as the combination area between the exoskeleton and the human body, and is connected to the axial hole of the hip joint 2 through the hip joint position shaft; the hip joint 2 and the four-bar knee joint 3 are connected to the bolts of the motor through a bracket; the four-bar knee joint 3 and the calf rod 4 are connected through the axial hole; the calf rod 4 and the sole shoe cover 5 are connected through a fisheye bearing; the sole shoe cover 5 is at the end of the exoskeleton and is used as the base of the back plate 1, the hip joint 2, the four-bar knee joint 3, and the calf rod 4; the lower limb exoskeleton mainly drives the hip joint and the knee joint, so two active degrees of freedom joints are arranged, and the hip joint 2, the four-bar knee joint 3, the calf rod 4, and the sole shoe cover 5 are mirror-mounted with the back plate 1 as the reference plane.

[0036] Combination Figure 2 The back plate 1 includes a plastic shell 101, a carbon plate 102, a lithium battery 103, a battery sheet metal fixing frame 104, a support plate support shaft 105, a square structure carbon tube 106, a waist plate structure frame 107, a support plate carbon tube 108, and a support plate 109; the plastic shell 101 and the carbon plate 102 are connected by copper nuts and bolts on the screw columns, and the carbon plate 102 and the square structure carbon tube 106 are connected to each other by riveting; the lithium battery 103 is installed between the two square structure carbon tubes 106, and is connected by bolts between the battery sheet metal fixing frame 104 and the pressure rivet nuts on the carbon plate 102, and the battery sheet metal fixing frame 1 04 is connected with the carbon plate 102 and the square structure carbon tube 106 by bolts; the support plate support shaft 105 is connected with the waist plate structure frame 107 by bolts through a semicircular hole structure positioning, the waist plate structure frame 107 and the square structure carbon tube 106 are connected by square slot positioning and bolt fastening, and the support plate support shaft 105 is installed on the waist plate structure frame 107; the support plate carbon tube 108 is connected to the support plate support shaft 105 through a rotating shaft, and the outside of the support plate 109 is covered, and the support plate 109 serves as an external connection device of the back plate 1 to support heavy objects, so that the support plate 109 can be unfolded when in use and folded and stored when not in use.

[0037] Combination Figure 3The hip joint 2 includes a back connecting plate 201, a plastic sleeve 202, a hip abduction shaft 203, a hip abduction frame 204, an external rotation shaft 205, a hip motor 206, a ball joint nut 207, a hip motor bracket 208, a ball joint 209, a hip motor output rod 210, a hip thigh rod 211, a rod-shaped elastic element 212, an external rotation shaft locking screw 213, a gasket 214, and an abduction shaft screw 215; the back connecting plate 201 is connected to the bolts of the hip abduction shaft 203 through the gasket 214 and the abduction shaft screw 215; the plastic sleeve 202 is assembled on the two end surfaces of the shaft hole of the hip abduction frame 204, and the flanges of the plastic sleeve 202 The hip abduction frame 204 is tightly mounted on the surface of the hip abduction frame 204, and the hip abduction shaft 203 is threadedly fixedly connected to the positioning groove of the back connecting plate 201 through the abduction shaft screw 215. The hip abduction frame 204 and the hip abduction shaft 203 form a revolute pair under the lubrication of the plastic sleeve 202; the external rotation shaft 205 is inserted and installed on the concentric axial holes on both sides of the hip abduction frame 204, and the positioning is formed by the surface contact between the boss on one side of the external rotation shaft 205 and the countersunk hole of the hip abduction frame 204. The external rotation shaft locking screw 213 is threadedly connected with the internal thread on the other side of the external rotation shaft 205, so that the external rotation shaft 205 is fastened in the axial hole of the hip abduction frame 204. , forming a rotation pair; the hip joint motor 206 is connected to the hip joint motor bracket 208 through a threaded hole on the surface; the ball joint nut 207 is connected to the ball joint joint 209 and is fixed to the hip joint motor bracket 208 through a thread, and the hip joint motor bracket 208 forms a rotation pair with the hip joint abduction frame 204 under the support of the external rotation axis 205; the ball joint joint 209 is ball-jointed with the rod-shaped elastic element 212; the hip joint motor output rod 210 is connected to the hip joint motor 206 by the pin positioning matching bolts on the output end surface of the hip joint motor 206; the hip joint thigh rod 211 is fastened to the hip joint motor output rod 21 through the axial hole matching bolts 0; both ends of the rod-shaped elastic element 212 are connected to the ball joint 209, one end of the ball joint 209 is fixed to the back connecting plate 201 and the other end is fixed to the hip joint motor bracket 208, the external rotation axis locking screw 213 is locked with the external rotation axis 205; the gasket 214 is fastened between the back connecting plate 201 and the abduction axis screw 215, the back connecting plate 201 is connected to the hip joint abduction axis 203 through the gasket 214 and the abduction axis screw 215, the hip joint abduction frame 204 and the hip joint abduction axis 203 form a revolute pair; the plastic sleeve 202 is used as a self-lubricating sleeve as a rotating intermediate piece to avoid hard friction of structural parts;The hip joint motor 206 is fixed to the hip joint motor bracket 208 by screws, and the hip joint motor output rod 210 is fixed to the output end of the hip joint motor 206, extending downward and connected to the hip joint thigh rod 211 by threads; the hip joint motor bracket 208 and the hip joint abduction frame 204 are connected to form a rotation pair through the external rotation shaft 205.

[0038] The rod-shaped elastic element 212 adopts a gas spring structure, is in a compressed state in the exoskeleton hip joint structure, and outputs a rebound force to the outside. The rod-shaped elastic element 212 is compressed and restricted on the back connecting plate 201 and the motor bracket 208, and the back connecting plate 201 is fixed on the lumbar plate structure frame 107. The hip joint motor bracket 208 connected to the hip joint abduction frame 204 is driven by the rebound force of the rod-shaped elastic element 212, which is converted into torque to balance the torque of the hip joint thigh itself relative to the rotation center of the back connecting plate 201, thereby offsetting the self-weight on the coronal plane and realizing passive self-weight compensation.

[0039] Combination Figure 4 , Figure 5 The four-bar linkage knee joint 3 includes a knee joint motor 301, a knee joint motor bracket 302, a hip joint thigh rod 211, a knee joint bearing seat 303, a calf connecting rod 304, a gas spring 305, a gas spring connecting rod 306, a fisheye joint 307, a motor output rod 308, an extension limit PU pad 309, and a flexion limit PU pad 310; the knee joint motor 301 is connected to the threaded hole of the knee joint motor bracket 302 by a bolt, the knee joint motor bracket 302 is threadedly connected to the hip joint thigh rod 211, the hip joint thigh rod 211 is fastened with the axial hole of the knee joint bearing seat 303 by bolts, the knee joint bearing seat 303 is connected to the calf connecting rod 304 by a bearing support by a plug screw, and the small The leg connecting rod 304 is connected to the gas spring 305 through a fisheye bearing, the gas spring 305 is connected to the gas spring connecting rod 306 through a screw, the gas spring connecting rod 306 is connected to the motor output rod 308 through the fisheye joint 307, and the motor output rod 308 is connected to the knee joint motor 301 by fastening with an axial hole and a bolt; the extension limit PU pad 309 and the flexion limit PU pad 310 are respectively fixed on the two sides of the step surface of the knee joint motor bracket 302, and the shapes of the extension limit PU pad 309 and the flexion limit PU pad 310 correspond to the side of the motor output rod 308, and they serve as the limit points for the extension and flexion of the knee joint to the limit, respectively, to protect the human body from being affected by the loss of control of the exoskeleton.

[0040] The four-link rod comprises the thigh rod 211 as the first link, i.e. the fixed link; the motor output rod 308 as the second link; the gas spring 305, the gas spring connecting rod 306 and the fisheye joint 307 are connected to form a third link; the calf connecting rod 304 is the fourth link; the knee joint drive is driven by the knee joint motor 301 to rotate, driving the second link to swing, the second link drives the third link to swing, and the fourth link rotates around the end point of the first link driven by the first two links, and the fourth link is the input of the calf rod rotational movement; the gas spring is an elastic element and can be compressed by impact; the third link composed of the gas spring 305, the gas spring connecting rod 306 and the fisheye joint 307 can provide cushioning when the exoskeleton is worn, reduce rigidity, and improve the structural flexibility of the lower limb exoskeleton.

[0041] After limiting, the range of motion of the calf rod is 150° extension and 50° flexion, which can fully meet the needs of heterogeneity and human joint wear. By simulating and calculating the angular velocity of the second and third links during the movement, the reduction ratio, i.e. the torque amplification factor, can be obtained by solving the inverse of the angular velocity ratio. Therefore, the use of a four-bar knee joint mechanism can effectively increase the output torque of the knee joint motor and convert it into torque on the knee joint rotation axis.

[0042] Combination Figure 6 , Figure 7 The calf rod 4 includes a leg length extension structure 401, a leg length adjustment mechanism 402, and a force sensor 403; the leg length extension structure 401 is connected to the leg length adjustment mechanism 402 through axial hole matching circumferential bolts, the leg length adjustment mechanism 402 is connected to the force sensor 403 through end face positioning circumferential bolts, and the force sensor 403 is connected to the four-bar knee joint 3 structure bolts.

[0043] The leg extension structure 401 includes a foot connector 411, a cushioning TPU pad 412, an inner extension tube 413, a first spring pin 414, a tension spring 415, a second spring pin 416, a sliding membrane 417, and an outer tube 418; the foot connector 411 is connected to the inner extension tube 413 by the first spring pin 414; the cushioning TPU pad 412 is placed between the foot connector 411 and the outer tube 418; the inner extension tube 413 is fixed to the foot connector 411 through a spring pin, The first spring pin 414 is inserted into the pin hole of the foot connector 411 and the inner extension tube 413 through interference fit, the tension spring 415 is connected between the first spring pin 414 and the second spring pin 416 through a pull ring, and the second spring pin 416 is fixed in the pin hole of the outer tube 418 through interference fit; the sliding membrane 417 is matched with the slot inside the outer tube 418 through the convex point to achieve axial positioning and fixation, and the outer tube 418 is the end of the mechanism, and its bottom surface is in contact with the buffer TPU pad 412. Considering that in the heterogeneous form, the distance between the foot and the hip joint will become longer when the person wearing the exoskeleton steps in the swing phase, the under-actuated design module is introduced in the ankle joint design, which can increase the degree of freedom of passive extension when kicking, and quickly retract to stabilize the foot support in the support phase. The under-actuated design of the ankle joint adopts the form of inner and outer telescopic tubes under spring tension, and the exploded view is shown in the figure. Under the constraint of the sliding membrane, the inner extension tube can slide in the outer tube to provide redundant displacement, and the tension spring can be unloaded after being stretched to reset itself. The design limits the calf rod stretching to 30mm to meet the needs of people's swinging steps.

[0044] The leg length adjustment mechanism 402 includes a friction locking rear opening 421, a locking sleeve 422, a friction locking front opening 423, a carbon fiber inner tube 424, a positioning pin 425, and a carbon fiber outer tube 426; the friction locking rear opening 421 is connected to the friction locking front opening 423 through a tapered thread, and the friction locking front opening 423 is glued to the end of the carbon fiber outer tube 426; the locking sleeve 422 is clamped on the outside of the carbon fiber inner tube 424 and can move up and down, the carbon fiber inner tube 424 and the positioning pin 425 are interference fit through the through hole on the tube surface, and the head of the positioning pin 425 is provided with a compression head, which can be adjusted by pressing The carbon fiber inner tube 424 is in the axial position of the carbon fiber outer tube 426. The carbon fiber outer tube 426 is provided with an outer tube hole, which cooperates with the compression head of the positioning pin 425 for positioning; the overall calf length is 20 mm per gear, and can be adjusted by 80 mm in total. After the carbon fiber inner tube 424 is stuck in a certain gear position through the positioning pin 425, and the carbon fiber inner tube 424 is cooperated with the gear position of the outer hole of the carbon fiber outer tube 426 through the positioning pin 425, the threads between the two friction locking ports are tightened together, so that the locking sleeve 422 tightly hugs the carbon fiber inner tube 424 through friction, thereby playing a role of friction locking.

[0045] Combination Figure 8 The sole shoe cover 5 includes a silicone rubber shoe cover 501, a foot fisheye bearing 502, and a foot support 503; the silicone rubber shoe cover 501 is connected to the foot support 503 through side bolts; the foot fisheye bearing 502 is pin-constrained with the foot support 503 through a bearing hole, and the foot support 503 is located on the side of the mechanism, and is used to transmit the load force of the lower limbs to the ground through the foot fisheye bearing 502, and the foot fisheye bearing 502 provides the foot with the degree of freedom of swinging and rotating.

[0046] The present invention also provides a method for using an active lower limb four-link heterogeneous exoskeleton, combining Fig. 9 , including the following steps:

[0047] Step 1: After the exoskeleton is powered on, the system is initialized and the IMU and motor encoder located on the human calf are calibrated to zero.

[0048] Step 2: When the person wearing the exoskeleton exercises, the posture sensor IMU monitors the human motion characteristics in real time, processes the movement speed of the human lower limbs, builds a human motion estimation model based on the human calf angle combined with the human gait characteristics, and builds a human-exoskeleton motion mapping model based on the human motion trajectory model combined with the exoskeleton related rod information, quantifies the human joint motion and maps it to the exoskeleton joint angle, and compares the angular velocities of the left and right calves of the human body. The exoskeleton joint corresponding to the side with lower angular velocity is multiplied by an attenuation function to reduce the interference with the human body during high-speed movement, so as to achieve a multi-terrain tracking effect, so that the exoskeleton controller drives the hip joint motor and the knee joint motor to output torque;

[0049] The attenuation function is constructed by comparing the angular velocity relationship between the two legs of the human lower limbs, and attenuating the torque output of the corresponding exoskeleton joint with a smaller angular velocity; the posture sensor IMU at the human calf is processed to approximate the movement speed of the human lower limbs. The approximate speed formula of the human lower limbs is shown as follows:

[0050] ;

[0051] in, and They represent the horizontal and vertical movement speeds of the human ankle joint, respectively. Represents the human knee joint angle, Represents the human ankle joint and The modulus of the vector sum of ;

[0052] The attenuation ratio of the joint torque is the weighted result of the angular velocity of the corresponding human lower leg, as shown in the following formula:

[0053] ;

[0054] in, and Respectively represent the speed of the left and right legs of the human body. and Represent the output gain of the left and right legs of the exoskeleton, Indicates adjustable gain, which can be adjusted according to actual conditions;

[0055] Step 3: The hip joint motor drives the knee joint motor bracket to rotate, and the thigh is extended through binding. The knee joint motor drives the knee joint motor output rod to rotate, and promotes the four-bar linkage to rotate in space, driving the calf connecting rod to rotate around the knee joint bearing seat, and the calf is extended through binding;

[0056] Step 4: Gait swing phase: In the leg extension structure, the human leg drives the extension spring fixed at the foot joint to extend, providing freedom for kicking, and rebounding to provide assistance at the beginning of the gait support phase;

[0057] Step 5: Gait support phase: the hip joint motor is stalled, the hip joint motor and the knee joint motor bracket remain relatively still to provide a support torque; the knee joint motor is stalled, the knee joint motor output rod and the knee joint motor remain relatively still to provide a support torque;

[0058] Step 6: The left and right legs output torque alternately, following the movement of the human body and supporting the human joints, and the program starts to run normally.

[0059] Furthermore, the rod-shaped elastic element 212 uses, but is not limited to, a gas spring, and may use elastic elements such as a tension spring, a compression spring, an elastic band, and a damper;

[0060] Furthermore, the arrangement of the rod-shaped elastic element 212 does not necessarily need to produce a thrust force at the bottom to offset the load, but may also produce a pull force at the top to offset the load;

[0061] Furthermore, the metal material used may include but is not limited to aluminum alloy, and the plastic material used may include but is not limited to ABS, PA, etc.

[0062] Example

[0063] Example 1: Collaborative support

[0064] When a normal person walks wearing the exoskeleton, the person's foot touches the ground with the exoskeleton foot, and the force sensor 403 feeds back the ground support reaction force data information. At the same time, the gas spring 305 in the four-bar linkage first buffers and absorbs part of the energy; after the hip joint motor and the knee joint motor receive the processor information, they output unidirectional torque to support the structure; taking the knee joint as an example, the motor pushes the four-bar linkage to move in the direction of expanding the knee joint angle, thereby achieving the effect of supporting the end calf rod.

[0065] Example 2: Active walking

[0066] When a patient walks in an exoskeleton, the human body is bound to the exoskeleton through straps or bands. When the exoskeleton detects the human body's intention to move, it actively drives the motor (position control) to drive the human body's hip and knee joints to move.

[0067] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0068] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An active lower limb four-link heterogeneous exoskeleton, characterized in that: The exoskeleton comprises a back plate (1), a hip joint (2), a four-bar knee joint (3), a shank rod (4), and a sole shoe cover (5); the back plate (1) is connected to the shaft hole of the hip joint (2) via a hip joint position shaft; the hip joint (2) and the four-bar knee joint (3) are connected to the bolts of the motor via a bracket; the four-bar knee joint (3) and the shank rod (4) are connected to each other via the shaft hole; the shank rod (4) and the sole shoe cover (5) are connected via a fisheye bearing; the sole shoe cover (5) is located at the end of the exoskeleton and is used as a base for the back plate (1), the hip joint (2), the four-bar knee joint (3), and the shank rod (4); The hip joint (2) comprises a back connecting plate (201), a plastic sleeve (202), a hip joint abduction shaft (203), a hip joint abduction frame (204), an external rotation shaft (205), a hip joint motor (206), a ball joint nut (207), a hip joint motor bracket (208), a ball joint (209), a hip joint motor output rod (210), a hip joint thigh rod (211), a rod-shaped elastic element (212), an external rotation shaft locking screw (213), a gasket (214), and an abduction shaft screw (215); the back connecting plate (201) is connected to the hip joint abduction shaft (203) by bolts via the gasket (214) and the abduction shaft screw (215). The plastic sleeve (202) is mounted on both end surfaces of the shaft hole of the hip abduction frame (204); the flange surface of the plastic sleeve (202) is tightly mounted on the surface of the hip abduction frame (204); the hip abduction shaft (203) is threadedly fixedly connected to the positioning groove of the back connecting plate (201) through the abduction shaft screw (215); the hip abduction frame (204) and the hip abduction shaft (203) form a rotation pair under the lubrication of the plastic sleeve (202); the external rotation shaft (205) is inserted and mounted on the concentric shaft holes on both sides of the hip abduction frame (204); a boss on one side of the external rotation shaft (205) and the hip abduction shaft (203) are connected to the hip abduction frame (204); The countersunk holes of the frame (204) are in surface contact to form positioning, the external rotation axis locking screw (213) is threadedly connected to the internal thread on the other side of the external rotation axis (205), and the external rotation axis (205) is fastened in the axial hole of the hip joint abduction frame (204) to form a rotation pair; the hip joint motor (206) is connected to the hip joint motor bracket (208) through the threaded hole on the surface; the ball joint nut (207) and the ball joint (209) are threadedly connected and fixed to the hip joint motor bracket (208), and the hip joint motor bracket (208) forms a rotation pair with the hip joint abduction frame (204) under the support of the external rotation axis (205); the ball joint (209) is connected to the rod-shaped elastic element (212) by a ball joint; the hip joint motor output rod (210) is connected to the hip joint motor (206) by being fastened with a pin positioning matching bolt on the output end surface of the hip joint motor (206); the hip joint thigh rod (211) is connected to the hip joint motor output rod (210) by being fastened with a shaft hole matching bolt; both ends of the rod-shaped elastic element (212) are connected to the ball joint joint (209), one end of the ball joint joint (209) is fixed to the back connecting plate (201) and the other end is fixed to the hip joint motor bracket (208), and the external rotation axis locking screw (213) is connected to the external rotation axis (205) by a locking screw;The washer (214) is fastened between the back connection plate (201) and the abduction shaft screw (215); the back connection plate (201) is connected to the hip joint abduction shaft (203) via the washer (214) and the abduction shaft screw (215); the hip joint abduction frame (204) and the hip joint abduction shaft (203) form a rotation pair; the hip joint motor (206) is fixed to the hip joint motor bracket (208) via screws; the hip joint motor output rod (210) is fixed to the output end of the hip joint motor (206) and extends downward to be connected to the hip joint thigh rod (211) via threads; the hip joint motor bracket (208) and the hip joint abduction frame (204) are connected via the external rotation shaft (205) to form a rotation pair. ; 2. The active lower limb four-link heterogeneous exoskeleton according to claim 1, characterized in that: The back plate (1) comprises a plastic shell (101), a carbon plate (102), a lithium battery (103), a battery sheet metal fixing frame (104), a support plate support shaft (105), a square structure carbon tube (106), a waist plate structure frame (107), a support plate carbon tube (108), and a support plate (109); the plastic shell (101) and the carbon plate (102) are connected via copper nuts and bolts on screw columns, and the carbon plate (102) and the square structure carbon tube (106) are connected to each other via rivets; the lithium battery (103) is installed between two of the square structure carbon tubes (106), and the battery sheet metal fixing frame (104) and the carbon plate (102) are connected via rivet nuts between the pressure rivet nuts The battery sheet metal fixing frame (104) is connected to the carbon plate (102) and the square structure carbon tube (106) by bolts; the support plate support shaft (105) is connected to the waist plate structure frame (107) by bolts through a semicircular hole structure positioning; the waist plate structure frame (107) and the square structure carbon tube (106) are connected by square slot hole positioning and bolt fastening; the support plate support shaft (105) is installed on the waist plate structure frame (107); the support plate carbon tube (108) is connected to the support plate support shaft (105) by a rotating shaft, and the support plate (109) is sleeved on the outside; the support plate (109) is used as an external connection device of the back plate (1) to support heavy objects.

3. The active lower limb four-link heterogeneous exoskeleton according to claim 2, characterized in that: The rod-shaped elastic element (212) adopts a gas spring structure and is in a compressed state in the exoskeleton hip joint structure to output a rebound force to the outside. The rod-shaped elastic element (212) is compressed and restricted on the back connecting plate (201) and the motor bracket (208), and the back connecting plate (201) is fixed on the waist plate structure frame (107). The hip joint motor bracket (208) connected to the hip joint abduction frame (204) is driven by the rebound force of the rod-shaped elastic element (212) to convert it into a torque to balance the torque of the hip joint thigh itself relative to the rotation center of the back connecting plate (201).

4. The active lower limb four-link heterogeneous exoskeleton according to claim 1, characterized in that: The four-link knee joint (3) comprises a knee joint motor (301), a knee joint motor bracket (302), a hip joint thigh rod (211), a knee joint bearing seat (303), a shank connecting rod (304), a gas spring (305), a gas spring connecting rod (306), a fisheye joint (307), a motor output rod (308), an extension limit PU pad (309), and a flexion limit PU pad (310); the knee joint motor (301) is connected to a threaded hole of the knee joint motor bracket (302) by a bolt, the knee joint motor bracket (302) is threadedly connected to the hip joint thigh rod (211), the hip joint thigh rod (211) and the axial hole of the knee joint bearing seat (303) are fastened with bolts, and the knee joint bearing seat (303) is connected to the shank connecting rod (304) by a plug screw through a bearing support. The calf connecting rod (304) is connected to the gas spring (305) via a fisheye bearing, the gas spring (305) is connected to the gas spring connecting rod (306) via a screw, the gas spring connecting rod (306) is connected to the motor output rod (308) via the fisheye joint (307), and the motor output rod (308) is connected to the knee joint motor (301) via a shaft hole and bolts; the extension limit PU pad (309) and the flexion limit PU pad (310) are respectively fixed to positions on both sides of the step surface of the knee joint motor bracket (302); the extension limit PU pad (309) and the flexion limit PU pad (310) have shapes corresponding to the side of the motor output rod (308), and serve as limit points for the extension and flexion of the knee joint to the limit, respectively, to protect the human body from being affected by the loss of control of the exoskeleton.

5. The active lower limb four-link heterogeneous exoskeleton according to claim 1, characterized in that: The shank rod (4) comprises a leg length extension structure (401), a leg length adjustment mechanism (402), and a force sensor (403); the leg length extension structure (401) and the leg length adjustment mechanism (402) are connected via axial hole matching circumferential bolts, the leg length adjustment mechanism (402) is connected to the force sensor (403) via end surface positioning circumferential bolts, and the force sensor (403) is connected to the four-bar knee joint (3) structure bolts; The leg extension structure (401) comprises a foot connector (411), a cushioning TPU pad (412), an inner extension tube (413), a first spring pin (414), a tension spring (415), a second spring pin (416), a sliding membrane (417), and an outer tube (418); the foot connector (411) is connected to the inner extension tube (413) by means of the first spring pin (414) through a pin-controlled fit; the cushioning TPU pad (412) is provided between the foot connector (411) and the outer tube (418); the inner extension tube (413) is fixed to the foot connector through a spring pin inserted therein. On the head (411), the first spring pin (414) is inserted into the pin holes of the foot connecting head (411) and the inner extension tube (413) by interference fit, the tension spring (415) is connected between the first spring pin (414) and the second spring pin (416) by a pull ring, and the second spring pin (416) is fixed in the pin hole of the outer tube (418) by interference fit; the sliding membrane (417) is matched with the inner groove of the outer tube (418) by a convex point, and the outer tube (418) serves as the end of the mechanism, and its bottom surface is in contact with the buffer TPU pad (412); The leg length adjustment mechanism (402) comprises a friction locking rear opening (421), a locking sleeve (422), a friction locking front opening (423), a carbon fiber inner tube (424), a positioning pin (425), and a carbon fiber outer tube (426); the friction locking rear opening (421) is connected to the friction locking front opening (423) via a tapered thread, and the friction locking front opening (423) is glued to the end of the carbon fiber outer tube (426); the locking sleeve (422) is clamped on the outside of the carbon fiber inner tube (424), the carbon fiber inner tube (424) and the positioning pin (425) are interference fit via a through hole on the tube surface, the head of the positioning pin (425) is provided with a compression head, and the axial position of the carbon fiber inner tube (424) on the carbon fiber outer tube (426) is adjusted by pressing, and the carbon fiber outer tube (426) is provided with an outer tube hole, which cooperates with the compression head of the positioning pin (425) for positioning.

6. The active lower limb four-link heterogeneous exoskeleton according to claim 1, characterized in that: The sole shoe cover (5) comprises a silicone rubber shoe cover (501), a foot fisheye bearing (502), and a foot support (503); the silicone rubber shoe cover (501) and the foot support (503) are connected via side bolts; the foot fisheye bearing (502) is pin-constrained with the foot support (503) via a bearing hole; the foot support (503) is located at the side of the mechanism and is used to transmit the load force of the lower limbs to the ground via the foot fisheye bearing (502).

7. A method for using an active lower limb four-link heterogeneous exoskeleton according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: After the exoskeleton is powered on, the system is initialized and the IMU and motor encoder located on the human calf are calibrated to zero. Step 2: When the person wearing the exoskeleton exercises, the posture sensor IMU monitors the human motion characteristics in real time, processes the movement speed of the human lower limbs, builds a human motion estimation model based on the human calf angle combined with the human gait characteristics, and builds a human-exoskeleton motion mapping model based on the human motion trajectory model combined with the exoskeleton related rod information, quantifies the human joint motion and maps it to the exoskeleton joint angle, and compares the angular velocities of the left and right calves of the human body. The exoskeleton joint corresponding to the side with lower angular velocity is multiplied by an attenuation function to reduce the interference with the human body during high-speed movement, so as to achieve a multi-terrain tracking effect, so that the exoskeleton controller drives the hip joint motor and the knee joint motor to output torque; Step 3: The hip joint motor drives the knee joint motor bracket to rotate, and the thigh is extended through binding. The knee joint motor drives the knee joint motor output rod to rotate, and promotes the four-bar linkage to rotate in space, driving the calf connecting rod to rotate around the knee joint bearing seat, and the calf is extended through binding; Step 4: Gait swing phase: In the leg extension structure, the human leg drives the extension spring fixed at the foot joint to extend, providing freedom for kicking, and rebounding to provide assistance at the beginning of the gait support phase; Step 5: Gait support phase: the hip joint motor is stalled, the hip joint motor and the knee joint motor bracket remain relatively still to provide a support torque; the knee joint motor is stalled, the knee joint motor output rod and the knee joint motor remain relatively still to provide a support torque; Step 6: The left and right legs output torque alternately, following the movement of the human body and supporting the human joints, and the program starts to run normally.

8. The method for using the active lower limb four-link heterogeneous exoskeleton according to claim 7, characterized in that: The decay function in step 2 is: The attenuation function is constructed by comparing the angular velocity relationship between the two legs of the human lower limbs, and attenuating the torque output of the corresponding exoskeleton joint with a smaller angular velocity; the posture sensor IMU at the human calf is processed to approximate the movement speed of the human lower limbs. The approximate speed formula of the human lower limbs is shown as follows: ； in, and They represent the horizontal and vertical movement speeds of the human ankle joint, respectively. Represents the human knee joint angle, Represents the human ankle joint and The modulus of the vector sum of ; The attenuation ratio of the joint torque is the weighted result of the angular velocity of the corresponding human lower leg, as shown in the following formula: ； in, and Respectively represent the speed of the left and right legs of the human body. and Represent the output gain of the left and right legs of the exoskeleton, Indicates adjustable gain, which can be adjusted according to actual conditions.

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