A wearable device for forearm based on four-bar two-cable tension structure

Abstract

The application discloses a kind of forearms wearable devices based on four-pole two cable tension structure, belong to upper limb wearable power-assisted equipment technical field.It mainly includes coaxial installation forearm rotating mechanism and wrist self-recovery mechanism.Forearm rotating mechanism is constituted by upper fixed ring, three-pole parallel mechanism and three equidistant distribution four-pole two cable tension integrated unit.Tension integrated unit and three-pole parallel mechanism realize multi-position steady-state switching and elastic power in forearm internal rotation / external rotation movement in cooperation.Wrist self-recovery mechanism includes hand support ring, four wrist support blocks, four branch chains and four elastic ropes, forms two-degree-of-freedom parallel tension structure, realizes the assistance, buffering and automatic reset of wrist flexion and extension and adduction and abduction movement.The device combines tension integrated structure and rigid parallel mechanism, has compliance, stability and lightweight characteristics, can match human movement mechanism, improve wearing comfort and safety.

Description

Technical Field

[0001] This invention relates to the field of wearable assistive devices for the upper limbs, specifically to a wearable forearm device based on a four-bar, two-cable tensioning structure. Background Technology

[0002] In recent years, with the development of human-machine collaboration and assistive technologies, wearable devices used to enhance or assist human movement capabilities have gradually gained attention in the engineering field, especially upper limb wearable devices, which have developed rapidly. The human upper limb has a wide range of motion and diverse movement forms, such as grasping, carrying, and dragging, which places high demands on the flexibility and stability of movements. Among these, the forearm, as a crucial part connecting the hand and upper arm, plays a key role in force transmission and precision manipulation. Therefore, forearm wearable devices, as an important type of upper limb wearable device, are of great significance in improving work efficiency, reducing muscle burden, and enhancing continuous work capacity.

[0003] However, while existing wearable forearm devices can assist the human body in performing some tasks to a certain extent, they still have many shortcomings in practical applications. First, most existing devices adopt rigid structures, resulting in a large overall size and weight, affecting wearing comfort and long-term use experience. For example, the adjustable backplate exoskeleton disclosed in patent CN202610013844.2 uses metal for both its drive unit and support frame, leading to a heavy overall weight and limited joint freedom of movement, making it difficult to adapt to different users' forearm shapes and movement habits. Second, some forearm exoskeletons are not well-matched to the biomechanical characteristics of the human forearm in their structural design, easily causing constraint incoordination or additional stress, reducing the naturalness and flexibility of movement. For example, the exoskeleton device and robot with it disclosed in patent CN202512052958.6 use an adjustable motor at each joint as the power source for the assist function, ignoring that the instantaneous center of rotation of the human joint changes with the joint's angle of motion, thus applying additional torque to the wearer's joints, causing difficulty or discomfort in joint movement. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention proposes a forearm wearable device based on a four-bar, two-cable tensioning structure. By combining the overall tensioning structure with a rigid parallel mechanism, and utilizing the four-bar, two-cable tensioning structure composed of two flexible tensioning units and four rigid compression units, the rigid-flexible coupling characteristics of the forearm wearable device are achieved. This invention enables the device to achieve flexibility, stability, and lightweight while also possessing a certain degree of rigidity and load-bearing capacity, thus solving problems such as overly complex structures, large overall device weight, and mismatch between device movement trajectory and human movement trajectory in traditional forearm wearable mechanisms.

[0005] This invention achieves multi-positional steady-state operation of the forearm wearable device through an innovative four-bar, two-cable tensioning overall structure. The three steady states of the four-bar, two-cable tensioning structure correspond to specific rotation angles in the three-bar parallel mechanism, enabling the forearm wearable device to maintain stability at the extreme external rotation, neutral, and internal rotation positions of the arm, thus matching the human body's movement mechanisms. Furthermore, utilizing the unique mechanical properties of the four-bar, two-cable tensioning structure during steady-state switching, an elastic thrust can be applied during the rotation of the three-bar parallel mechanism, thereby providing assistance to the forearm wearable device during internal and external rotation processes.

[0006] It should be noted that the naming of related components in this invention is for descriptive purposes only and is used to illustrate the technical solution. It should not be construed as a limitation of this invention.

[0007] This invention proposes a wearable forearm device based on a four-bar, two-cable tension structure, mainly comprising a forearm rotation mechanism and a wrist self-recovery mechanism. The wrist self-recovery mechanism is coaxially mounted with the forearm rotation mechanism, positioned above it, and connected via pre-drilled bolt holes at the bottom and top of each mechanism. This connection determines the relative position of the wrist and forearm, preventing wrist sprains caused by the wrist self-recovery mechanism's rotation center not being aligned with the forearm rotation axis.

[0008] The forearm rotation mechanism mainly includes an upper fixing ring, an upper cover plate, a support ring, a central shaft, a three-bar parallel mechanism, a four-bar two-cable tensioning unit, a sleeve plate, a bearing, and a clamping plate for connecting the wrist self-recovery mechanism. The three-bar parallel mechanism is located below the upper fixing ring, and the three four-bar two-cable tensioning units are located between the upper fixing ring and the three-bar parallel mechanism and are evenly distributed at equal intervals. The upper end of each tensioning unit is hinged to a lug reserved on the bottom surface of the upper fixing ring, and its lower end is hinged to the upper surface of the parallel mechanism. The upper end of the central shaft is fixedly connected to the upper fixing ring, passes through the middle of the tensioning unit, and its lower end can slide up and down into the upper plate of the three-bar parallel mechanism, so that the parallel mechanism, the tensioning unit, and the upper fixing ring can rotate synchronously. The upper fixed ring and the bottom surface of the three-bar parallel mechanism are fixed coaxially by sleeve plates and bearings installed inside, ensuring that the relative height between the upper and lower fixed rings remains constant and that the axes of the upper and lower fixed rings coincide, preventing injury to the human body during forearm rotation due to misalignment of the upper and lower rings. Specifically, the three sleeve plates are evenly spaced circumferentially distributed inside the upper fixed ring and the three-bar parallel mechanism. A groove is provided on the outer side of the upper end for fitting the inner ring of the bearing, and a perforated boss is provided on the inner side for installing a support ring to connect the three sleeve plates into a single sleeve. The lower end of the sleeve plates is fixedly connected to the bottom surface of the three-bar parallel mechanism. The inner ring of the bearing is fitted onto the inner ring of the upper fixed ring, and the outer ring of the bearing is fitted into the groove at the upper end of the sleeve plate. The upper cover plate is fixedly connected to the top of the upper fixed ring after the bearing is installed, assisting in fixing the outer ring of the bearing and preventing the bearing from slipping out of the upper fixed ring during rotation.

[0009] The three-bar linkage mechanism includes an upper cover plate, an outer upper ring plate, an inner upper ring plate, three ball-head connecting rods, a base plate, an outer lower ring plate, and an inner lower ring plate. The lower surface of the upper cover plate and the upper surfaces of the outer and inner upper ring plates each have three equally spaced spherical grooves, forming a rotating pair with the ball heads at one end of the three ball-head connecting rods. Similarly, the upper surface of the base plate and the lower surfaces of the outer and inner upper ring plates also have three equally spaced spherical grooves at the same positions, forming a rotating pair with the ball heads at the other end of the three ball-head connecting rods. Through the transmission of the three ball-head connecting rods, the upper cover plate can rotate coaxially with the base plate. A clip is fixedly installed on the inner side of the base plate, used to connect the wearer's arm end to the base plate of the three-bar linkage mechanism, thereby fixing the relative positional relationship between the arm and the device.

[0010] The four-bar, two-cable tensioning unit includes two stretchable springs, two rigid upper connecting rods, and two rigid lower connecting rods. One end of each rigid upper connecting rod is hinged to a lug on the bottom surface of the upper fixed ring, and the other end is hinged to one end of the lower connecting rod. The other end of the lower connecting rod is hinged to a lug on the upper surface of the upper cover plate. The two upper connecting rods and the two lower connecting rods are installed symmetrically on the left and right sides, and the four connecting rods are arranged in a rectangular pattern. One of the two springs is horizontally connected between the hinge points of the upper and lower connecting rods on the left and right sides, and the other spring is vertically arranged, with one end connected near the hinge point of the upper connecting rod with the upper fixed ring, and the other end connected near the hinge point of the lower connecting rod with the upper cover plate in the three-bar parallel mechanism.

[0011] It should be noted that there is a corresponding relationship between the steady state of the tensioning system and the rotation angle of the three-bar parallel mechanism. When it is necessary to apply assisted movement to the forearm, the palm is clenched and passes through the sleeve composed of three sleeve plates in the forearm rotation mechanism and into the wrist self-recovery mechanism, so that the palm rests at the center of the upper surface of the wrist self-recovery mechanism; when the wearer performs forearm internal or external rotation, the palm opens, and the wrist self-recovery mechanism and the upper fixing ring rotate under the action of the palm, which drives the upper plate of the parallel mechanism to rotate clockwise synchronously through the intermediate shaft and the two-bar four-cable tensioning system, thereby transmitting power to the three-bar parallel mechanism, forcing the upper plate of the parallel mechanism to rotate clockwise. As the plate moves downward, the vertically mounted tension springs in the tensioning system are stretched under the action of the upper plate, while the horizontally mounted springs are compressed. As the forearm rotates continuously, the deformation of the two springs also increases. When the vertical and horizontal springs are compressed and stretched to a certain extent, the internal stress of the four-bar, two-cable tensioning system is rebalanced, allowing the tensioning system to reach a new equilibrium position. At this point, the three-bar parallel mechanism rotates to the limit angle of the forearm's forward or outward rotation, achieving positional matching between the tensioning steady state and the three-bar parallel mechanism.

[0012] The wrist mechanism consists of a hand support ring, four wrist support blocks, four branches, and four elastic ropes. The four branches are evenly arranged in a circle around the hand support ring, with one end hinged to the hand support ring and the other end hinged to the corresponding wrist support block. The hand support ring is positioned directly above the wrist support blocks. The four wrist support blocks are fixedly connected to the upper surface of the upper fixed ring and are distributed at equal intervals in a circle. The four elastic ropes are connected between the hand support ring and the corresponding wrist support blocks, forming a self-stabilizing and self-recovering parallel tension structure.

[0013] It should be noted that when the wearer's wrist moves, the hand support ring moves with the wrist, causing the wrist support block to shift accordingly via a chain. The elastic cord deforms during this process, providing resistance and cushioning for the wrist movement, thus assisting and protecting it. Simultaneously, due to the presence of the elastic cord, the wrist mechanism can automatically adjust its position and angle to better follow the wrist's movement trajectory, improving wearing comfort and stability.

[0014] The chain consists of an upper arm, a middle connecting block, and a lower arm. One end of the upper arm is hinged to the hand support ring, and the other end is hinged to one end of the middle connecting block. The other end of the middle connecting block is hinged to one end of the lower arm, and the other end of the lower arm is hinged to the wrist support block. With the four chains mutually restricting each other, the wrist self-recovery mechanism possesses the same two degrees of freedom as the human wrist: adduction / abduction and flexion / extension movements. When the wrist performs adduction / abduction or flexion / extension movements, the four chains rotate and deform accordingly, while the elastic rope stretches or compresses, providing resistance and support for the wrist movement. This resistance and support help the user better control the range and force of wrist movement, reducing the risk of injury caused by excessive wrist movement angles. Moreover, the self-stabilizing characteristic of the wrist self-recovery mechanism allows it to automatically return to its initial neutral position after the wrist movement stops, relying on the elastic restoring force of the elastic rope. This feature not only facilitates user operation but also ensures the stability and neatness of the device when not in use.

[0015] Beneficial Effects: Through the synergistic effect of the four-bar, two-cable tensioned overall structure and the three-bar parallel mechanism, the wearable device achieves dynamic locking and elastic assistance in multiple stable positions during the internal and external rotation of the forearm. The wrist self-recovery mechanism, through the cooperation of four branches and elastic cords, assists and protects the wrist's adduction, abduction, flexion, and extension movements. This wearable device, through the organic combination of the tensioned overall structure and the rigid parallel mechanism, combines flexibility, stability, and lightweight characteristics, while possessing suitable stiffness and load-bearing capacity, effectively solving the problems of complex structures and excessive weight in traditional devices. Furthermore, the multi-stable position design is highly compatible with human movement mechanisms, avoiding the generation of additional stress and improving the device's fit with human joint movements and wearing comfort. The elastic cords of the wrist self-recovery mechanism provide cushioning and resistance, preventing wrist sprains and reducing the risk of sports injuries. The wrist mechanism can automatically return to a neutral position, ensuring the stability and regularity of the device's use. Attached Figure Description

[0016] To clearly illustrate the embodiments and related technical solutions of the present invention, the accompanying drawings involved in the embodiments will be briefly described below. It should be understood that the following drawings are only for illustrating some embodiments of the present invention. Those skilled in the art can also obtain other related technical solutions and drawings based on these drawings without any inventive effort.

[0017] Figure 1 A schematic diagram of a forearm wearable device based on a four-bar, two-cable tensioning structure provided in this embodiment of the invention. Figure I .

[0018] Figure 2 A schematic diagram of a forearm wearable device based on a four-bar, two-cable tensioning structure provided in this embodiment of the invention. Figure II .

[0019] Figure 3 This is a top view of the forearm rotation mechanism of a forearm wearable device based on a four-bar two-cable tensioning structure, provided as an embodiment of the present invention.

[0020] Figure 4 This is a schematic diagram of the forearm rotation mechanism of a forearm wearable device based on a four-bar, two-cable tensioning structure, provided as an embodiment of the present invention.

[0021] Figure 5 This is a cross-sectional view of the forearm rotation mechanism of a forearm wearable device based on a four-bar two-cable tensioning structure, provided as an embodiment of the present invention.

[0022] Figure 6 This is a schematic diagram of the three-bar parallel mechanism of a forearm wearable device based on a four-bar two-cable tensioning structure, provided as an embodiment of the present invention.

[0023] Figure 7 An exploded view of a three-bar parallel mechanism of a forearm wearable device based on a four-bar, two-cable tensioning structure, provided as an embodiment of the present invention.

[0024] Figure 8 This is a schematic diagram of a four-bar, two-cable tensioning unit structure for a forearm wearable device based on a four-bar, two-cable tensioning structure, provided as an embodiment of the present invention.

[0025] Figure 9 This is a schematic diagram of the wrist self-recovery mechanism of a forearm wearable device based on a four-bar two-cable tension structure, provided as an embodiment of the present invention.

[0026] Figure 10 This is a cross-sectional view of the wrist self-recovery mechanism of a forearm wearable device based on a four-bar two-cable tension structure, provided as an embodiment of the present invention.

[0027] Figure 11This is a schematic diagram of the inward (outward) rotation state of a forearm wearable device based on a four-bar two-cable tensioning structure, provided as an embodiment of the present invention.

[0028] Labeling Explanation: 1. Forearm Rotation Mechanism; 101. Upper Fixed Ring; 102. Upper Cover Plate; 103. Support Ring; 104. Sleeve Plate; 105. Four-Bar Two-Cable Tensioning Unit; 10501. Upper Connecting Rod; 10502. Lower Connecting Rod; 10503. Tension Spring; 106. Clamping Plate; 107. Central Shaft; 108. Three-Bar Parallel Mechanism; 10801. Upper Cover Plate; 10802. Outer Ring 1. Plate; 10803, Inner Ring Upper Plate; 10804, Ball Head Connector; 10805, Outer Ring Lower Plate; 10806, Inner Ring Lower Plate; 10807, Base Plate; 109, Bearing; 2. Wrist Self-Recovery Mechanism; 201, Hand Support Ring; 202, Branch Chain; 20201, Upper Arm; 20202, Intermediate Connecting Block; 20203, Lower Arm; 203, Elastic Rope; 204, Wrist Support Block. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] See Figure 1 and Figure 2 This invention provides a wearable forearm device based on a four-bar, two-cable tension structure, which mainly includes a forearm rotation mechanism 1 and a wrist self-recovery mechanism 2. The wrist self-recovery mechanism 2 is located above the forearm rotation mechanism 1 and is coaxially mounted with the forearm rotation mechanism 1. Specifically, the two are fixedly connected by bolt holes pre-drilled at the bottom and top, respectively, to accurately determine the relative position of the wrist and forearm, avoiding wrist sprains caused by the rotation center of the wrist self-recovery mechanism 2 not being on the rotation axis of the forearm rotation mechanism 1.

[0031] See Figures 1 to 5The forearm rotation mechanism 1 is the core component of this invention for achieving the function of assisting forearm internal / external rotation movement and maintaining multiple stable states at extreme positions. It mainly includes an upper fixing ring 101, an upper cover plate 102, a support ring 103, three central shafts 107, a three-bar parallel mechanism 108, a clamping plate 106, three four-bar two-cable tensioning integral units 105, three sleeve plates 104, and a bearing 109. Among them, the three-bar parallel mechanism 108 is located below the upper fixing ring 101, and the three four-bar two-cable tensioning integral units 105 are evenly distributed at equal intervals between the upper fixing ring 101 and the three-bar parallel mechanism 108. The upper end of each tensioning integral unit is hinged to the lug reserved on the bottom surface of the upper fixing ring 101 by bolts, and the lower end is hinged to the connecting block provided on the upper surface of the parallel mechanism. The upper end of the central shaft 107 is fixedly connected to the upper fixed ring 101, the middle part passes through the tensioning unit, and the lower end can slide up and down into the upper plate of the three-bar parallel mechanism 108, so that the parallel mechanism, the tensioning unit, and the upper fixed ring 101 can rotate synchronously.

[0032] See Figures 2 to 5 The bottom surfaces of the upper fixing ring 101 and the three-bar parallel mechanism 108 are rotatably and coaxially fixed through sleeve pieces 104 and bearings 109 disposed inside the upper fixing ring 101. This ensures that the relative height between the upper fixing ring 101 and the lower fixing ring remains constant and that their rotation axes coincide, preventing injury to the wearer's forearm during rotation due to misalignment. Specifically, three sleeve pieces 104 are circumferentially distributed at equal intervals inside the upper fixing ring 101 and the three-bar parallel mechanism 108. The upper outer side of the sleeve piece 104 has a groove, which can be fixedly connected to the inner ring of the bearing 109 by an interference fit. The outer ring of the bearing 109 is placed on a small protrusion on the inner ring of the upper fixing ring 101, thus achieving a rotatable connection between the upper fixing ring 101 and the sleeve piece 104. The inner side of the sleeve piece 104 has a perforated protrusion, on which a support ring 103 is installed, thereby connecting the three sleeve pieces 104 into a single sleeve structure, enhancing the strength of the top of the sleeve. The upper cover plate 10801 is fixed to the bolt holes on the surface of the upper fixing ring 101 by bolts. It cooperates with the upper fixing ring 101 to achieve axial positioning of the outer ring of the bearing 109. This ensures that the rotation axis of the bearing 109 always coincides with the rotation axis of the upper fixing ring 101, while preventing the bearing 109 from coming out of the upper fixing ring 101 during rotation.

[0033] See Figure 5 , Figure 7 and Figure 8The three-bar parallel mechanism 108 includes an upper cover plate 10801, an outer ring upper plate 10802, an inner ring upper plate 10803, three ball joint connecting rods 10804, a base plate 10807, an outer ring lower plate 10805, and an inner ring lower plate 10806. The outer ring upper plate 10802 and the inner ring upper plate 10803 are located on the inner and outer sides of the lower surface of the upper cover plate 10801, and the three are fixedly connected by bolts. The semi-circular groove on the bottom surface of the upper cover plate 10801 and the corresponding circular grooves on the upper surfaces of the outer and inner rings cooperate to form a complete ball joint groove, which is used to connect with one end of the ball joint connecting rod 10804 to form a spherical kinematic pair. The base plate is located directly below the upper cover plate 10801. Similarly, the outer ring lower plate 10805, the inner ring upper plate 10803, and the base plate 10807 are also fixed to each other by bolts. The circular grooves cooperate to form a complete ball joint groove, which is connected to the other end of the ball head connecting rod 10804 to form a kinematic pair.

[0034] See Figure 2 and Figure 7 The clip 106 is fixed to the inner side of the base plate 10807 of the three-bar parallel mechanism 108. It is used to connect the end of the wearer's arm to the base plate 10807 of the three-bar parallel mechanism 108 to fix the relative positional relationship between the wearer's arm and the entire forearm wearable device.

[0035] See Figure 2 , Figure 4 and Figure 6 The four-bar, two-cable tensioning unit 105 is the core component of the forearm rotation mechanism 1, enabling multi-steady-state switching and elastic assistance. Each unit includes a central shaft 107, two stretchable tension springs 10503, two rigid upper connecting rods 10501, and two rigid lower connecting rods 10502. The upper ends of the two rigid upper connecting rods 10501 are hinged to the lugs pre-reserved on the bottom surface of the upper fixing ring 101, and the lower ends of the two rigid upper connecting rods 10501 are hinged to the upper ends of the corresponding rigid lower connecting rods 10502. The lower ends of the two rigid lower connecting rods 10502 are hinged to the left and right sides of the connecting block on the upper surface of the upper cover plate 10801 of the three-bar parallel mechanism 108. The two upper connecting rods 10501 and the two lower connecting rods 10502 are arranged symmetrically from left to right, forming a rectangular spatial four-bar configuration.

[0036] See Figure 2 , Figure 4 , Figure 6 and Figure 11Two stretchable tension springs 10503 are connected horizontally and vertically to the hinge points of four rigid connecting rods, respectively. The horizontally arranged tension spring 10503 is connected at both ends to the hinge points of the upper connecting rod 10501 and the lower connecting rod 10502 on the left and right sides, respectively. The vertically arranged tension spring 10503 has one end connected near the hinge point between the upper connecting rod 10501 and the upper fixed ring 101, and the other end connected near the hinge point between the lower connecting rod 10502 of the parallel mechanism and the upper cover plate 10801 of the parallel mechanism. It should be noted that the hinge points connected to the left and right ends of each tension spring 10503 are not adjacent, thus ensuring that the tensioning unit can achieve steady-state switching through the redistribution of tensile and compressive internal forces when under stress.

[0037] See Figure 4 and Figure 5 The upper end of the central shaft 107 is fixedly connected to a blind hole inside the upper fixed ring 101. The middle part passes through the center of the rectangular configuration of the four-bar two-cable tensioning unit. Its lower end can be slidably inserted into the upper cover plate 10801 of the three-bar parallel mechanism 108, so that the upper fixed ring 101, the tensioning unit and the upper cover plate 10801 of the parallel mechanism can rotate synchronously, and provide guidance and constraint for the internal force changes of the tensioning unit during the movement.

[0038] See Figure 2 and Figure 11When assistive movement of the forearm is required, the palm clenches and passes through the sleeve composed of three sleeve plates 104 in the forearm rotation mechanism 1 and into the wrist self-recovery mechanism 2, so that the palm rests at the center of the upper surface of the wrist self-recovery mechanism 2 (i.e., position A). The working principle of the forearm rotation mechanism 1 of this invention is as follows: When the wearer performs forearm internal or external rotation, the palm drives the wrist self-recovery mechanism 2 and the upper fixing ring 101 fixedly connected to it to rotate. The rotation of the upper fixing ring 101 is transmitted to the upper cover plate 10801 of the three-bar parallel mechanism 108 through the central shaft 107 and three four-bar two-cable tensioning integral units 105, forcing the upper cover plate 10801 to rotate synchronously clockwise (or counterclockwise). The rotation of the upper cover plate 10801 is converted into rotational and downward force on the base plate 10807 through the constraint of the three ball joints 10804. The downward force is transmitted through the upper cover plate 10801 to the vertically arranged second tension spring 10503 in each four-bar two-cable tensioning unit 105, causing it to be stretched; simultaneously, due to the angle change between the four rigid links, the horizontally arranged first tension spring 10503 is compressed. As the forearm rotates continuously, the deformation of the two springs increases continuously, and the internal stress of the tensioning unit is constantly redistributed. When the deformation of the vertical and horizontal springs reaches a critical value, the internal tension and pressure of the four-bar two-cable tensioning unit 105 reach a new equilibrium, allowing the entire unit to enter a new stable state. At this time, the three-bar parallel mechanism 108 rotates precisely to a position corresponding to the forearm's internal or external rotation limit angle. This process achieves a precise match between the "multi-position steady state" of the tensioning unit and the rotation angle of the three-bar parallel mechanism 108, enabling the device to remain stable at the arm's external rotation limit position, neutral position, and internal rotation limit position, achieving a high degree of matching between the wearable device and the human body's movement mechanism.

[0039] It should be noted that during the steady-state switching process of the four-bar, two-cable tensioning unit 105, the stretched and compressed springs store elastic potential energy. When the wearer intends to move from the neutral position to the extreme position of the forearm, these springs release potential energy, applying an elastic thrust to the movement of the parallel mechanism, thereby achieving an assisting effect on the internal and external rotation movements of the human body, effectively reducing muscle load, and realizing the elastic assisting function of the wearable device during the movement of the human forearm.

[0040] See Figure 9 and Figure 10The wrist self-recovery mechanism 2 assists and protects the flexion, extension, adduction, and abduction movements of the wrist. It mainly includes a hand support ring 201, four wrist support blocks 204, four branches 202, and four elastic ropes 203. The hand support ring 201 is located directly above the four wrist support blocks 204. The four wrist support blocks 204 are fixedly connected to the upper surface of the upper fixed ring 101 in the forearm rotation mechanism 1, and are distributed in a circumferentially spaced manner, providing a stable mounting base for the entire wrist mechanism. The four branches 202 are evenly arranged circumferentially around the hand support ring 201, with adjacent branches 202 spaced 90° apart. One end of each branch 202 is hinged to the hand support ring 201, and the other end is hinged to the corresponding wrist support block 204, thus forming a spatial parallel mechanism. The four elastic ropes 203 are respectively connected between the hand support ring 201 and the corresponding wrist support block 204. Specifically, one end of each elastic rope 203 is fixed to a preset connection point of the hand support ring 201, and the other end is fixed to a preset connection point on the upper surface of the corresponding wrist support block 204. Through the combined action of the four branches 202 and the four elastic ropes 203, the wrist self-recovery mechanism 2 forms a parallel tension structure that is self-stabilizing and self-recovering, enabling it to automatically return to its initial equilibrium position after being subjected to external force.

[0041] See Figure 9 and Figure 10 The branch 202 consists of an upper arm 20201, an intermediate connecting block 20202, and a lower arm 20203. One end of the upper arm 20201 is hinged to the hand support ring 201, and the other end is hinged to one end of the intermediate connecting block 20202; the other end of the intermediate connecting block 20202 is hinged to one end of the lower arm 20203; and the other end of the lower arm 20203 is hinged to the corresponding wrist support block 204. Preferably, the hinges can be connected together by snap-fit ​​fasteners, so that each branch 202 constitutes a spatial open-chain structure with three degrees of rotational freedom.

[0042] It should be noted that, under the spatial geometric constraints and kinematic coupling of the four branches 202, the wrist self-recovery mechanism 2 is restricted to a motion mode with two rotational degrees of freedom: palmar flexion / dorsiflexion and adduction / abduction, which are consistent with the human wrist's motion mechanism. This two-degree-of-freedom characteristic enables the wrist self-recovery mechanism 2 to accurately follow the complex motion trajectory of the human wrist, providing effective assistance and protection for the wrist joint.

[0043] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A wearable forearm device based on a four-bar, two-cable tensioning structure, characterized in that, include: A forearm rotation mechanism (1) and a wrist self-recovery mechanism (2) are provided. The wrist self-recovery mechanism (2) is coaxially mounted with the forearm rotation mechanism (1) and is located above the forearm rotation mechanism (1). The forearm rotation mechanism (1) includes an upper fixing ring (101), an upper cover plate (102), a support ring (103), a bearing (109), a sleeve plate (104), a clamping plate (106), a three-bar parallel mechanism (108), a central shaft (107), and a four-bar two-cable tensioning integral unit (105). The three-bar parallel mechanism (108) is located below the upper fixing ring (101). The four-bar two-cable tensioning unit (105) is connected between the upper fixed ring (101) and the three-bar parallel mechanism (108); the bottom surfaces of the upper fixed ring (101) and the three-bar parallel mechanism (108) are rotatably coaxially fixed through a sleeve and a bearing (109); the upper end of the central shaft (107) is fixedly connected to the upper fixed ring (101), and passes through the four-bar two-cable tensioning unit (105) in the middle, and its lower end can slide up and down into the three-bar parallel mechanism (108) so that the parallel mechanism can rotate synchronously with the tensioning unit and the upper fixed ring; the four-bar two-cable tensioning unit (105) is connected between the upper fixed ring (101) and the three-bar parallel mechanism (108); the bottom surfaces of the upper fixed ring (101) and the three-bar parallel mechanism (108) are rotatably coaxially fixed through a sleeve and a bearing (109); the lower end of the central shaft (107) is fixedly connected to the upper fixed ring (101), and passes through the four-bar two-cable tensioning unit (105) in the middle, and its lower end can slide up and down into the three-bar parallel mechanism (108) so that the parallel mechanism can rotate synchronously with the tensioning unit and the upper fixed ring; the four-bar two-cable tensioning unit (105) is connected to the upper fixed ring (101) and the three-bar parallel mechanism (108); the bottom surfaces of the upper fixed ring (101) and the three-bar parallel mechanism (108) are rotatably coaxially fixed through a sleeve and a bearing (109); the bottom surface ... two-cable tensioning unit (105 5) Includes two rigid upper connecting rods (10501), two rigid lower connecting rods (10502), and two stretchable tension springs (10503). One end of each of the two upper connecting rods (10501) is hinged to the upper fixed ring (101), and the other end is hinged to one end of the corresponding lower connecting rod (10502). The other end of each of the two rigid lower connecting rods (10502) is hinged to the three-bar parallel mechanism (108). One tension spring (10503) is horizontally connected to the hinge point between the upper connecting rod (10501) and the lower connecting rod (10502), and the other is vertically connected to the upper connecting rod and the lower connecting rod. The hinge point of the upper fixed ring and the hinge point of the lower connecting rod with the upper surface of the parallel mechanism; the wrist self-recovery mechanism (2) includes a hand support ring (201), multiple wrist support blocks (204), multiple branches (202) and multiple elastic ropes (203). The wrist support block (204) is fixedly connected to the upper surface of the upper fixed ring (101). One end of the branch (202) is hinged to the hand support ring (201) and the other end is hinged to the corresponding wrist support block (204). The elastic rope (203) is connected between the hand support ring (201) and the corresponding wrist support block (204).

2. The forearm wearable device based on a four-bar, two-cable tensioning structure according to claim 1, characterized in that, The forearm rotation mechanism (1) includes a sleeve plate (104) and a bearing (109). The upper end of the sleeve plate (104) is sleeved with the inner ring of the bearing (109). The outer ring of the bearing (109) is sleeved on the inner ring of the upper fixing ring (101) so that the upper fixing ring (101) and the bottom surface of the three-bar parallel mechanism (108) are rotatably coaxially fixed.

3. The forearm wearable device based on a four-bar, two-cable tensioning structure according to claim 1, characterized in that, The upper cover plate (102) is fixedly connected to the top of the upper fixing ring (101) and is used to assist in fixing the outer ring of the bearing (109).

4. The forearm wearable device based on a four-bar, two-cable tensioning structure according to claim 1, characterized in that, There are three sleeve pieces (104), which are circumferentially distributed at equal intervals inside the upper fixing ring (101) and the three-bar parallel mechanism (108). The three sleeve pieces (104) are connected to form an integral sleeve structure through the support ring (103).

5. The forearm wearable device based on a four-bar, two-cable tensioning structure according to claim 1, characterized in that, The three-bar parallel mechanism (108) includes an upper cover plate (10801), a bottom plate (10807), and three ball-head connecting rods (10804). Both the upper cover plate (10801) and the bottom plate (10807) are provided with spherical grooves. The two ends of the three ball-head connecting rods (10804) respectively form a rotating pair with the spherical grooves on the upper cover plate (10801) and the bottom plate (10807).

6. The forearm wearable device based on a four-bar, two-cable tensioning structure according to claim 1, characterized in that, The number of the four-bar two-cable tensioning integral unit (105) is three, and the three four-bar two-cable tensioning integral units (105) are evenly distributed at equal intervals between the upper fixing ring (101) and the three-bar parallel mechanism (108).

7. The forearm wearable device based on a four-bar, two-cable tensioning structure according to claim 1, characterized in that, In the four-bar two-cable tensioning integral unit (105), the two upper connecting rods (10501) and the two lower connecting rods (10502) are installed in a left-right symmetrical manner, and the four connecting rods are distributed in a rectangular shape.

8. The forearm wearable device based on a four-bar, two-cable tensioning structure according to claim 1, characterized in that, There are four wrist support blocks (204), which are fixedly connected to the upper surface of the upper fixing ring (101) in a circumferentially spaced manner. There are four branches (202), which are evenly arranged in a circumference with the hand support ring (201) as the center.

9. The forearm wearable device based on a four-bar, two-cable tensioning structure according to claim 1, characterized in that, The branch (202) includes an upper arm (20201), an intermediate connecting block (20202), and a lower arm (20203). One end of the upper arm (20201) is hinged to the hand support ring (201), and the other end is hinged to one end of the intermediate connecting block (20202). The other end of the intermediate connecting block (20202) is hinged to one end of the lower arm (20203), and the other end of the lower arm (20203) is hinged to the wrist support block (204).

10. The forearm wearable device based on a four-bar, two-cable tensioning structure according to claim 1, characterized in that, The clip (106) is fixedly disposed on the inner side of the base plate (10807) of the three-bar parallel mechanism (108) to connect the end of the wearer's arm to the base plate (10807), thereby fixing the relative position of the entire wearable device and the wearer's forearm.

Images