Patent Publication Number: US-11376148-B2

Title: Combined structure of wearable apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims under 35 U.S.C. § 119(a) the benefit of Korean Patent Application No. 10-2019-0039702, filed Apr. 4, 2019, the entire contents of which are incorporated by reference herein. 
     BACKGROUND 
     (a) Technical Field 
     The present disclosure relates generally to a combined structure of a wearable apparatus, more particularly, to a structure configured to be combined with a wearer to simulate the rotation of a wearer&#39;s shoulder joint through a cross four-bar linkage. 
     (b) Description of the Related Art 
     A wearable robot is a robot that assists movement of a wearer&#39;s body by putting the robot on a specific part of the body or by mounting the robot to a specific part, and is designed to be used for medical, military, or industrial purposes. In particular, in the case of wearable robots for the workplace, such wearable robots are designed to prevent injuries and to support muscle strength by reducing a load applied to the wearer. The wearable robot is one made by mimicking a wearer&#39;s exoskeleton, and it is important to design a joint to have the same motion as the actual motion of the body. 
     In particular, a wearable muscular strength assisting apparatus includes a manual support mechanism configured to support a person supporting the weight of a tool. A typical manual support mechanism is configured to compensate for gravity under a range of positions by using a combination of structural elements, springs, cables, and pulleys. The configuration of these devices provides gravity compensation within a limited operating range of operation. 
     However, the conventional wearable apparatus is problematic in that it is impossible to simulate the lateral rotation of a wearer&#39;s shoulder joint. In particular, when a wearer performs internal rotation or external rotation of his or her shoulder joint, a center of rotation is moved instead of being a fixed center of rotation. As a result, when an upper arm assisting apparatus is configured to be rotatable about a single rotation shaft in the up-and-down direction, it is impossible to simulate the rotational motion of the shoulder joint. 
     Further, to solve the above problem, when a plurality of rotation shafts in the up-and-down direction is provided, an extra degree of freedom occurs, so additional coupling to the wearer is required, and during the external rotation of the shoulder joint, the rotation shafts and the components thereof may be projected to the outside, which may cause a great risk of accident. 
     The foregoing is intended merely to aid in the understanding of the background of the present disclosure, and is not intended to mean that the present disclosure falls within the purview of the related art that is already known to those skilled in the art. 
     SUMMARY 
     Accordingly, the present disclosure proposes a combined structure of a wearable apparatus, in which it is possible to stably simulate internal rotation or external rotation of a wearer&#39;s shoulder joint with a single degree of freedom. 
     In order to achieve the above object, according to one aspect of the present disclosure, there is provided a combined structure of a wearable apparatus, the combined structure including: a torso fastening part fixedly fastened to a wearer&#39;s torso; a fixed link extending from the torso fastening part to a position above a wearer&#39;s shoulder; a first link and a second link being respectively coupled to the fixed link to be laterally rotatable, and crossing each other while being vertically spaced apart from each other; a rotatable part disposed at a position above the wearer&#39;s shoulder, and coupled to the first link and the second link to be laterally rotatable; a connecting part coupled to the rotatable part to extend downward from the rotatable part; and an upper arm module coupled to be rotatable upward or downward about the connecting part while an end thereof is coupled to the connecting part at a position corresponding to an upper end portion of the wearer&#39;s upper arm, and fastened to the wearer&#39;s upper arm while extending in a longitudinal direction of the wearer&#39;s upper arm. 
     The torso fastening part may be disposed at a wearer&#39;s back side, and may include: an upper plate disposed at an upper portion of the torso fastening part to be brought in contact with the wearer&#39;s back side; a lower plate disposed at a lower portion of the torso fastening part to be brought in contact with the wearer&#39;s back side; and a rear side link extending in a vertical direction to connect the upper plate and the lower plate together. 
     The rear side link may be rotatably coupled to the upper plate or the lower plate about an extended longitudinal direction thereof as a rotation axis. 
     The upper plate may be fastened to the wearer&#39;s back side at a position higher than the wearer&#39;s shoulder, and the fixed link may be disposed at a position above the wearer&#39;s shoulder by extending forward from a position where the upper plate is laterally extended. 
     The lower plate may be fastened to the wearer&#39;s back side at a position corresponding to a wearer&#39;s pelvis, and the lower plate may be coupled to the rear side link to be rotatable forward or backward. 
     The lower plate may be provided with a first coupling portion and a second coupling portion protrudingly extending from positions vertically spaced apart from each other, and the rear side link may be coupled to the first coupling portion and the second coupling portion, wherein the first coupling portion is rotatably coupled to the rear side link, and the second coupling portion is slidably coupled to the rear side link. 
     The fixed link may extend forward from the torso fastening part to be disposed at a position above the wearer&#39;s shoulder, and may be rotatably coupled to the first link and the second link respectively at a first point and a second point spaced apart from each other. 
     The rotatable part may be in the form of a plate extending parallel to the ground, may be rotatably coupled to the first link and the second link respectively at a third point and a fourth point spaced apart from each other, and may be coupled to the connecting part at a fifth point spaced apart from the third point and the fourth point. 
     The upper arm module may be applied with a rotational torque that rotates the upper arm module upwardly with respect to the connecting part, and the fifth point of the rotatable part coupled with the connecting part may be disposed at a position behind an intersection of the first link and the second link. 
     The first link or the second link may be coupled to the fixed link or the rotatable part through a thrust bearing, and may extend on planes parallel to each other while being vertically spaced from each other. 
     The combined structure may further include: a first magnetic body disposed at an end of the rotatable part spaced apart from positions where the rotatable part is coupled to the first link and the second link; and a second magnetic body disposed at a lateral end of the torso fastening part, wherein the first magnetic body and second magnetic body are attracted to each other. 
     The upper arm module may be disposed at an outer side of a wearer&#39;s upper arm, and may include a support that supports the wearer&#39;s upper arm from a lower portion of the wearer&#39;s upper arm by extending toward an inner side of the wearer&#39;s upper arm through the lower portion of the wearer&#39;s upper arm. 
     According to the combined structure of a wearable apparatus of the present disclosure, it is possible to exactly simulate a center of rotation that has moved according to internal rotation or external rotation of the wearer&#39;s shoulder joint, thereby allowing motion to be implemented without any discomfort. 
     Further, without requiring an additional fastening mechanism to a wearer&#39;s body or configuration protruding by being spaced apart from the wearer&#39;s body, motion is implemented with a single degree of freedom, so it is possible to improve stability. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features and other advantages of the present disclosure will be more clearly understood from the following detailed description when taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a rear view showing a combined structure of a wearable apparatus according to an embodiment of the present disclosure; 
         FIG. 2  is a top view showing the combined structure of a wearable apparatus according to an embodiment of the present disclosure; 
         FIGS. 3 and 4  are views showing joints constituting a shoulder of a human body and movements according to rotation; 
         FIG. 5  is a view comparing a moving path of rotation according to the combined structure of a wearable apparatus according to an embodiment of the present disclosure with a moving path of rotation according to a single axis; 
         FIG. 6  is a view showing a moving process of the combined structure of a wearable apparatus according to an embodiment of the present disclosure according to internal rotation of a shoulder joint; 
         FIGS. 7A, 7B, and 7C  are schematic views showing a moving process of the combined structure of a wearable apparatus according to an embodiment of the present disclosure according to internal rotation of a shoulder joint; 
         FIGS. 8 and 9  are views showing movements of a first link and a second link included in the combined structure of a wearable apparatus according to an embodiment of the present disclosure; 
         FIG. 10  is an enlarged view showing the first link and the second link included in the combined structure of a wearable apparatus according to an embodiment of the present disclosure; 
         FIG. 11  is an exploded perspective view showing the first link and the second link included in the combined structure of a wearable apparatus according to an embodiment of the present disclosure; 
         FIG. 12  is a view showing a forward and backward rotation structure of the combined structure of a wearable apparatus according to an embodiment of the present disclosure; and 
         FIGS. 13 and 14  are views showing a lateral rotation structure of the combined structure of a wearable apparatus according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE DISCLOSURE 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Throughout the specification, unless explicitly described to the contrary, the word “comprise” and variations such as “comprises” or “comprising” will be understood to imply the inclusion of stated elements but not the exclusion of any other elements. In addition, the terms “unit”, “-er”, “-or”, and “module” described in the specification mean units for processing at least one function and operation, and can be implemented by hardware components or software components and combinations thereof. 
     Further, the control logic of the present disclosure may be embodied as non-transitory computer readable media on a computer readable medium containing executable program instructions executed by a processor, controller or the like. Examples of computer readable media include, but are not limited to, ROM, RAM, compact disc (CD)-ROMs, magnetic tapes, floppy disks, flash drives, smart cards and optical data storage devices. The computer readable medium can also be distributed in network coupled computer systems so that the computer readable media is stored and executed in a distributed fashion, e.g., by a telematics server or a Controller Area Network (CAN). 
     In the following description, the structural or functional description specified to exemplary embodiments according to the concept of the present disclosure is intended to describe the exemplary embodiments, so it should be understood that the present disclosure may be variously embodied, without being limited to the exemplary embodiments. 
     The exemplary embodiments according to the concept of the present disclosure may be variously modified and may have various shapes, so examples of which are illustrated in the accompanying drawings and will be described in detail with reference to the accompanying drawings. However, it should be understood that the exemplary embodiments according to the concept of the present disclosure are not limited to the embodiments which will be described hereinbelow with reference to the accompanying drawings, but various modifications, equivalents, additions and substitutions are possible, without departing from the scope and spirit of the disclosure. 
     It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element, from another element. For instance, a first element discussed below could be termed a second element without departing from the teachings of the present disclosure. Similarly, the second element could also be termed the first element. 
     It will be understood that when an element is referral to as being “coupled” or “connected” to another element, it can be directly coupled or connected to the other element or intervening elements may be present therebetween. In contrast, it should be understood that when an element is referred to as being “directly coupled” or “directly connected” to another element, there are no intervening elements present. Further, the terms used herein to describe a relationship between elements, for example, “between”, “directly between”, “adjacent” or “directly adjacent” should be interpreted in the same manner as those described above. Unless otherwise defined, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
     Hereinbelow, an exemplary embodiment of the present disclosure will be described in detail with reference to the accompanying drawings. Throughout the drawings, the same reference numerals will refer to the same or like parts. 
       FIG. 1  is a rear view showing a combined structure of a wearable apparatus according to an embodiment of the present disclosure; and  FIG. 2  is a top view showing the combined structure of a wearable apparatus according to an embodiment of the present disclosure. 
     With reference to  FIGS. 1 and 2 , a combined structure of a wearable apparatus according to an embodiment of the present disclosure includes: a torso fastening part  100  fixedly fastened to a wearer&#39;s torso; a fixed link  200  extending from the torso fastening part  100  to a position above a wearer&#39;s shoulder; a first link  300  and a second link  400  being respectively coupled to the fixed link  200  to be laterally rotatable, and crossing each other while being vertically spaced apart from each other; a rotatable part  500  disposed at a position above the wearer&#39;s shoulder, and coupled to the first link  300  and the second link  400  to be laterally rotatable; a connecting part  600  coupled to the rotatable part  500  to extend downward from the rotatable part  500 ; and an upper arm module  700  coupled to be rotatable upward or downward about the connecting part  600  while an end thereof is coupled to the connecting part  600  at a position corresponding to an upper end portion of a wearer&#39;s upper arm, and fastened to the wearer&#39;s upper arm while extending in a longitudinal direction of the wearer&#39;s upper arm. 
     The torso fastening part  100 , which is fastened to the wearer&#39;s torso, may be secured to the wearer&#39;s torso via a separate harness or the like. 
     The fixed link  200  may be fixedly coupled to the torso fastening part  100  and extend toward the position above the wearer&#39;s shoulder. In particular, the fixed link may extend from the torso fastening part  100  to respective opposite sides of the shoulder of the wearer. 
     The rotatable part  500  may be rotatably coupled to the fixed link  200  through the first link  300  and the second link  400 . In particular, the first link  300  and the second link  400  are coupled to the rotatable part  500  and the fixed link  200  respectively so as to be laterally rotatable, and thus, both the fixed link  200  and the rotatable part  500  may be rotatably coupled to each other in a direction parallel to the ground. 
     The first link  300  and second link  400  may be respectively coupled to the rotatable part  500  and fixed link  200  to form a four-bar linkage structure. In particular, the first link  300  and the second link  400  may be arranged so as to be spaced apart from each other in the vertical direction and cross each other while being extended on planes parallel to each other. 
     The first link  300  and the second link  400  may be laterally rotatable about the fixed link  200  fixed to the wearer&#39;s torso, and the rotatable part  500  coupled to the first link  300  and the second link  400  to be laterally rotatable is rotated about an instantaneous center of rotation (ICR)  540  formed at the intersection of the first link  300  and the second link  400 . 
     In other words, the rotatable part  500  is rotated about the ICR  540  moved according to rotations of the first link  300  and the second link  400 , so that the end of the rotatable part  500  can be rotated to simulate the movement of the end of the wearer&#39;s shoulder joint. 
     The upper arm module  700  may be coupled to the connecting part  600  to be rotatable upward or downward about an end of the upper arm module. In particular, the connecting part  600  may include: a first connecting part  610  extending downward from one point of the rotatable part  500 ; and a second connecting part  620  extending from the first connecting part  610  to a position corresponding to the upper end portion of the wearer&#39;s upper arm along the direction parallel to the ground. 
     The first connecting part  610  may be disposed at the wearer&#39;s back side, and the second connecting part  620  may extend from the wearer&#39;s back side to the wearer&#39;s outer side. The end of the upper arm module  700  may be coupled to the second connecting part  620  at the wearer&#39;s outer side to be rotatable about a position that matches the center of rotation of the wearer&#39;s upper arm. 
     As another embodiment, the first connecting part  610  and the second connecting part  620  may be integrally formed into one configuration, and directly connect the rotatable part  500  and the upper arm module  700  together. 
     Accordingly, as the rotatable part is connected to the crossed first link  300  and second link  400 , it is possible to naturally simulate the movement of the end of the wearer&#39;s shoulder joint. 
     In particular, the upper arm module  700  may extend in the extension direction of the wearer&#39;s upper arm, and may generate rotational torque that rotates the wearer&#39;s upper arm upward or downward. A torso support can support a reaction against this rotational torque in the torso. 
     The upper arm module  700  may be provided therein with an elastic body such as a spring generating an elastic force, wherein the elastic body is connected to a wire wound or unwound according to an angle at which the upper arm module  700  is rotated upward or downward about one end thereof, whereby the elastic force of the elastic body can be varied according to the rotation angle of the upper arm module  700 . 
     Further, the rotational torque is varied according to the magnitude of the elastic force and the direction where the elastic force is applied, and a profile of the rotational torque according to the rotation angle of the upper arm module  700  may be designed by providing a cam in the upper arm module  700 , which induces the wire to be wound or the elastic body to be deformed according to the rotation angle of the upper arm module  700 . 
     The upper arm module  700  may be disposed at an outer side of the wearer&#39;s upper arm, and the upper arm module  700  may include a support  710  that supports the wearer&#39;s upper arm from a lower portion of the wearer&#39;s upper arm by extending to an inner side of the wearer&#39;s upper arm through the lower portion of the wearer&#39;s upper arm. The support  710  may be in a shape that surrounds the lower portion of the wearer&#39;s upper arm. 
       FIGS. 3 and 4  are views showing joints constituting a shoulder of a human body and movements according to rotation. 
     With reference to  FIGS. 3 and 4 , the shoulder of the human body is composed of complex joints J 1 , J 2 , and J 3 , and rotations thereof are combined to realize the upward and downward movements of the scapula S, and upward and downward rotation of the shoulder including internal rotation and external rotation. 
     In particular, the shoulder joint consists of a sterno-clavicular joint J 1 , an acromio-clavicular joint J 2 , and a scapulo-thoracic joint J 3  connected to each other on a horizontal plane. When the shoulder joint rotates internally or externally on the horizontal plane, the sterno-clavicular joint J 1  and the acromio-clavicular joint J 2  simultaneously rotate, and thus, a complex rotation occurs in which the scapula S and the clavicle C rotate. Accordingly, the wearer&#39;s upper arm moves while the center of rotation MP 1  thereof is changed. This rotational motion cannot be simulated with a single rotation axis, as described below. 
       FIG. 5  is a view comparing a moving path of rotation MP 1  according to the combined structure of a wearable apparatus according to an embodiment of the present disclosure with a moving path of rotation according to a single axis MP 2 . 
     With further reference to  FIG. 5 , the combined structure of a wearable apparatus according to an embodiment of the present disclosure has a four-bar linkage structure in which the first link  300  and the second link  400  cross each other, so the ICR  540  is rotated as the first link  300  and the second link  400  are laterally rotated, whereby an end (a fifth point  530  to be described below) of the rotatable part  500  can be moved to simulate the movement of the center of rotation MP 1  of the upper arm that is the end of the wearer&#39;s shoulder. 
     In particular, compared to a path moving along a circumference based on a single rotation axis MP 2 , the end of the rotatable part of the rotatable part can be moved to exactly simulate the movement of the center of rotation MP 1  of the upper arm that is the end of the wearer&#39;s shoulder. As a result, it is possible to exactly simulate the movement of the wearer, so that motion without any discomfort is possible. 
       FIG. 6  is a view showing a moving process of the combined structure of a wearable apparatus according to an embodiment of the present disclosure according to internal rotation of a shoulder joint, depicting a moving path MP 3  of the instantaneous center of rotation (ICR)  540 ;  FIGS. 7A, 7B, and 7C  are schematic views showing a moving process of the combined structure of a wearable apparatus according to an embodiment of the present disclosure according to internal rotation of a shoulder joint;  FIGS. 8 and 9  are views showing movements of a first link and a second link included in the combined structure of a wearable apparatus according to an embodiment of the present disclosure; and  FIG. 10  is an enlarged view showing the first link and the second link included in the combined structure of a wearable apparatus according to an embodiment of the present disclosure. 
     With further reference to  FIGS. 6 to 10 , the fixed link  200  may extend forward from the torso fastening part  100  to be disposed at a position above the wearer&#39;s shoulder, and may be rotatably coupled to the first link  300  and the second link  400  respectively at a first point  210  and a second point  220  spaced apart from each other. 
     The fixed link  200  may be disposed at a position above the wearer&#39;s shoulder by extending forward from the torso fastening part  100  fastened to the wearer&#39;s back side. In particular, the first point  210  and the second point  220  of the fixed link  200  may be spaced apart from each other in the forward and backward direction, and may be coupled to the first link  300  at the first point  210  and with the second link  400  at the second point  220 . 
     The first link  300  and second link  400  may extend outwardly from the fixed link  200 , and the rotatable part  500  may be coupled to the first link  300  and the second link  400  while being positioned outside the fixed link  200 . 
     Further, the rotatable part  500  may be in the form of a plate extending parallel to the ground, be rotatably coupled to the first link  300  and the second link  400  respectively at a third point  510  and a fourth point  520  spaced apart from each other, and be coupled to the connecting part  600  at a fifth point  530  spaced apart from the third point  510  and the fourth point  520 . 
     The rotatable part  500  may extend in the direction parallel to the ground to be coupled to the first link  300  and the second link  400  at the third point  510  and the fourth point  520  spaced apart from each other in the forward and backward direction. Thus, the first link  300  and the second link  400  may be coupled to each other while extending in the direction parallel to the ground to cross each other between ends thereof. 
     In particular, the first link  300  and the second link  400  are vertically spaced from each other, wherein the first link  300  may be coupled to a position under the fixed link  200  and the rotatable part  500 , and the second link  400  may be coupled to a position above the fixed link  200  and the rotatable part  500 , and the reverse is also possible. Thus, the first link  300  and the second link  400  may cross each other without interference. 
     The fifth point  530  may be spaced apart from the third point  510  and the fourth point  520  of the rotatable part  500 , and may be an outer end of the rotatable part  500 . In other words, the fifth point  530  may be outer laterally disposed to form a triangle along with the third point  510  and the fourth point  520 , and the rotatable part  500  may be a triangular shape having the third point  510 , the fourth point  520 , and the fifth point  530  as corners. 
     Thus, the rotatable part  500  rotatably coupled to the first link  300  and the second link  400  is laterally moved by the first link  300  and the second link  400  rotating as a cross four-bar linkage, and accordingly, the fifth point  530  of the rotatable part  500  is capable of rotational movement in which the center of rotation is moved instead of the fixed center of rotation. 
     The connecting part  600  may be coupled to the rotatable part  500  at the fifth point  530 . In particular, the connecting part may be coupled to the first connecting part  610  extending downwardly from the fifth point  530 . In particular, the fifth point  530  and the first connecting part  610  may be disposed at a position behind the wearer&#39;s shoulder. 
     The second connecting part  620  may extend to a position corresponding to the upper end portion of the wearer&#39;s upper arm along the direction parallel to the ground by being coupled to the first connecting part  610 . In particular, the rotatable part  500  and the first connecting part  610 , and the first connecting part  610  and the second connecting part  620  may be coupled so that the lateral rotation is restrained. Thus, in order to simulate the external rotation or internal rotation of the wearer&#39;s shoulder, compared to the conventional case where the rotatable part  500  and the first connecting part  610 , and the first connecting part  610  and the second connecting part  620  are rotatably coupled to form an excessive degree of freedom, according to the present disclosure, it is possible to exactly simulate the movement of the end of the wearer&#39;s shoulder using a cross four-bar linkage. 
     In particular, as shown in  FIG. 6 , the combined structure of a wearable apparatus may further include: a first magnetic body  550  disposed at an end of the rotatable part  500  spaced apart from positions where the rotatable part is coupled to the first link  300  and the second link  400  respectively; and a second magnetic body  140  disposed at a lateral end of the torso fastening part  100 , wherein the first magnetic body  550  and second magnetic body  140  may be attracted to each other. 
     The first magnetic body  550  may be disposed at a position coincident with or at a position adjacent to the fifth point  530  of the rotatable part  500 . The second magnetic body  140  may be disposed at an outer lateral end extending laterally from the torso fastening part  100 , and may be disposed at a position extending from the torso fastening part  100  to the fixed link  200 . 
     The first magnetic body  550  and second magnetic body  140  may be attracted to each other due to magnetism. When no external force is applied, the rotatable part  500  may be fixedly coupled to the torso fastening part  100  by the magnetic force between the first magnetic body  550  and the second magnetic body  140 , as shown by the alternate long and short dash line of  FIG. 6 . 
     Accordingly, the combined structure of a wearable apparatus is maintained in a folded state when not worn by the wearer, thereby facilitating storage and transportation. 
     The upper arm module  700  may be applied with a rotational torque that rotates the upper arm module  700  upwardly with respect to the connecting part  600 , and the fifth point  530  of the rotatable part  500  coupled with the connecting part  600  may be disposed at a position behind an intersection of the first link  300  and the second link  400 . 
     As described above, the rotational torque that rotates the upper arm module  700  upwardly with respect to the connecting part  600  may be generated in the upper arm module  700 , and a reaction thereagainst may be supported at the torso support through the connecting part  600 . 
     In particular, between the fifth point  530  of the rotatable part  500  coupled with the connecting part  600 , and the intersection of the first link  300  and the second link  400  that is the ICR  540  of the rotatable part  500 , an offset spaced apart in the forward and backward direction may occur. In particular, since the fifth point  530  is disposed at a position behind the ICR  540  of the rotatable part  500 , when the rotational torque is generated in the upper arm module  700 , a force by which the rotatable part  500  is rotated forward about the ICR  540  may be generated. 
     Accordingly, without a separate harness or strap, the rotatable part  500  or the connecting part  600  is brought in close contact with the wearer&#39;s body and wearer&#39;s shoulder to follow the internal rotation and external rotation of the shoulder. 
       FIGS. 8 and 9  show the movement of the first link  300  and the second link  400  according to the rotation thereof at the first point  210  to the fourth point  520 . In particular, the first link  300  and the second link  400  form a trajectory such as the following equation. 
     
       
         
           
             
               
                 
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                               sin 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               
                                 θ 
                                 3 
                               
                             
                           
                           
                             
                               cos 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               
                                 θ 
                                 3 
                               
                             
                           
                         
                       
                       ] 
                     
                     ⁡ 
                     
                       [ 
                       
                         
                           
                             
                               ℓ 
                               3 
                             
                           
                         
                         
                           
                             0 
                           
                         
                       
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     Accordingly, as the first link  300  and the second link  400  are rotated about the fixed link  200  fixed to the wearer as a fixed point, the third point  510  and the fourth point  520  of the rotatable part  500  are determined, and thus, a trajectory along which the fifth point  530  is moved is formed. 
       FIG. 11  is an exploded perspective view showing the first link  300  and the second link  400  included in the combined structure of a wearable apparatus according to an embodiment of the present disclosure. 
     With further reference to  FIG. 11 , the first link  300  or the second link  400  may be coupled to the fixed link  200  or the rotatable part  500  through a thrust bearing  800 , and may extend on planes parallel to each other while being vertically spaced from each other. 
     In other words, the first link  300  and the second link  400  are respectively coupled to the fixed link  200  and the rotatable part  500  to be vertically spaced from each other, and may include the bearings  800  to be rotatably coupled to the first point  210 , the second point  220 , the third point  510 , and the fourth point  520 , which are junction points. 
     In particular, the bearing  800  may be a thrust bearing  800  or an axial bearing  800 . Thus, the thrust force acting in the direction of the rotation axis can be supported. 
     Referring again to  FIGS. 1 and 2 , the torso fastening part  100  may be disposed at a wearer&#39;s back side, and may include: an upper plate  110  disposed at an upper portion of the torso fastening part  100  to be brought in contact with the wearer&#39;s back side; a lower plate  130  disposed at a lower portion of the torso fastening part to be brought in contact with the wearer&#39;s back side; and a rear side link  120  extending in the vertical direction to connect the upper plate  110  and the lower plate  130  together. 
     In particular, the upper plate  110  may be fastened to the wearer&#39;s back side at a position higher than the wearer&#39;s shoulder, and the fixed link  200  may be disposed at a position above the wearer&#39;s shoulder by extending forward from a position where the upper plate  110  is laterally extended. 
     The upper plate  110  may be positioned behind the wearer&#39;s cervical vertebrae to be disposed above the wearer&#39;s shoulder, thereby being supported by being brought in contact with the wearer&#39;s neck. The fixed link  200  may be disposed at a position above the wearer&#39;s shoulder by extending forward while extending outer laterally from the upper plate  110 . 
       FIG. 12  is a view showing a forward and backward rotation structure of the combined structure of a wearable apparatus according to an embodiment of the present disclosure. 
     With further reference to  FIG. 12 , the lower plate  130  may be fastened to the wearer&#39;s back side at a position corresponding to a wearer&#39;s pelvis, and the lower plate  130  may be coupled to the rear side link  120  to be rotatable forward or backward. 
     In particular, the lower plate  130  may be provided with a first coupling portion  131  and a second coupling portion  132  protrudingly extending from positions vertically spaced apart from each other, and the rear side link  120  may be coupled to the first coupling portion  131  and the second coupling portion  132 , wherein the first coupling portion  131  may be rotatably coupled to the rear side link  120 , and the second coupling portion  132  may be slidably coupled to the rear side link  120 . 
     The first coupling portion  131  may be rotatably coupled to the rear side link by a hinge coupling  123  between the lower plate  130  and the rear side link  120 . 
     The second coupling portion  132  may be provided at a position downwardly spaced apart from the first coupling portion  131 . The second coupling portion  132  may be formed with a sliding groove  133  at the lower plate  130 , and the rear side link  120  may be formed with a sliding protrusion  124  sliding while being inserted in the sliding groove  133 , so that the sliding protrusion  124  may slide while being inserted in the sliding groove  133  by the rotation at the first coupling portion  131 . 
     Accordingly, it is possible to naturally simulate the motion of bending the waist forward or straightening the back backward. 
       FIGS. 13 and 14  are views showing a lateral rotation structure of the combined structure of a wearable apparatus according to an embodiment of the present disclosure. 
     With further reference to  FIGS. 13 and 14 , the rear side link  120  may be rotatably coupled to the upper plate  110  or the lower plate  130  about an extended longitudinal direction as a rotation axis. 
     Accordingly, it is possible to simulate the rotational motion of the wearer&#39;s upper body in the Yaw direction. 
     As an embodiment, the rear side link  120  may be integrally rotated along with the upper plate  110  about a Yaw rotation axis which is a rotation axis parallel to the extended longitudinal direction of the rear side link  120 . On the contrary, the rear side link  120  may be coupled to the lower plate  130  to be rotatable about a Yaw rotation axis which is a rotation axis parallel to the lower plate. 
     In particular, as shown in  FIG. 13 , the rear side link  120  may be constituted by an upper link  121  and a lower link  122  coupled to each other through a hinge joint  125  to be mutually rotatable about the Yaw rotation axis, wherein the upper link  121  may be disposed at an upper portion to be coupled to the upper plate  110 , and the lower link  122  may be coupled to the lower plate  130  at a position under the upper link  121  to be rotatable along with the upper link  121  about the Yaw rotation axis. Accordingly, the wearer can rotate the torso based on the lumbar spine. 
     Although a preferred embodiment of the present disclosure has been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the disclosure as disclosed in the accompanying claims.