Method for manufacturing meta-structured fabric type actuator capable of individual current control for each zone and the fabric type actuator

Abstract

A method for manufacturing a fabric actuator of a metastructure having a negative Poisson ratio and the fabric actuator may include the steps of: creating a re-entrant structure by tying a pair of shape memory alloy wires to a unit cell of a re-entrant expansion structure; repeating the step of creating the re-entrant structure using a plurality of pairs of shape memory alloy wires to create a fabric structure in which pairs of shape memory alloy wires are connected in a two-dimensional direction; and manufacturing a fabric actuator of a single object by tying the pairs of wires of the fabric structure using a mold.

Description

Technology Field

[0001] The present disclosure relates to a method for manufacturing a metastructure fabric type actuator capable of individual current control by zone and to a fabric type actuator. Background Technology

[0002] Wearable haptic devices are being actively developed to be lightweight and compact, allowing them to be easily worn like everyday clothing without interfering with activities, while providing augmentation effects. In particular, the importance of wearable haptic devices is being highlighted as a medium that can naturally and intuitively connect virtual environments with the real world, such as VR (virtual reality), AR (augmented reality), MR (mixed reality), and XR (extended reality).

[0003] Existing motor and pneumatic-based wearable haptic devices increase fatigue and cause discomfort when worn due to their heavy weight and large size. Additionally, movement during daily activities can cause the device to fail to stay in place and easily fall off, or act as a hindrance to daily activities.

[0004] Shape memory alloy wires capable of generating force depending on temperature are primarily used in the development of lightweight and soft wearable devices. For example, shape memory alloy wires are woven into a fabric form and used as fabric-type actuators or artificial muscles capable of generating force when heated.

[0005] However, conventional shape memory alloy-based wearable fabric actuators have the inconvenience of requiring hot air to be supplied from the outside to generate force.

[0006] In addition, for shape memory alloy-based fabric actuators to be used as haptic devices, a single actuator must provide various information, but conventional shape memory alloy-based fabric actuators are only capable of single relaxation / contraction, which shows a significant limitation in the diversity of information provided.

[0007] Most wearable devices, including conventional fabric actuators, possess high contractile force, but when contraction occurs along one axis, they relax along the other axis, resulting in a limited range of contraction / relaxation during actual wear. In particular, this type of deformation is referred to as a structure that deforms with a positive Poisson ratio, which presents a problem in that it has limitations in adhering to curved surfaces (most surfaces of the human body) or bent shapes (elbows, knees, skull, etc.). The problem to be solved

[0008] The present disclosure provides a method for manufacturing a metastructure fabric actuator capable of surface conductivity modification and individual current control by zone by applying a Perlin thin film coating to the surface of the fabric actuator, wherein a shape memory alloy wire is knotted into a re-entrant structure and such re-entrant structure is tessellated so that the overall structure has a metastructure having a negative Poisson ratio, and the fabric actuator itself. means of solving the problem

[0009] According to one feature, the method comprises the steps of: creating a re-entrant structure by tying a pair of shape memory alloy wires to a unit grid of a re-entrant expansion structure; repeating the step of creating the re-entrant structure using multiple pairs of shape memory alloy wires to create a fabric structure in which pairs of shape memory alloy wires are connected in a two-dimensional direction; and manufacturing a fabric-type actuator of a single object by tying the pairs of wires of the fabric structure using a mold.

[0010] The above re-entry structure can have a negative Poisson ratio in the form formed through the knotting procedure.

[0011] After the above manufacturing step, the method further includes a step of forming a film using Chemical Vapor Deposition (CVD) on the surface of the fabric-type actuator, and the film can enable individual current control of the fabric-type actuator in multiple zone units.

[0012] The above forming step involves applying a Parylene coating to the surface of the fabric-type actuator to insulate the surface of the conductive shape memory alloy, and through the insulation, the current may be suppressed from flowing to adjacent areas other than the area where the current flows.

[0013] The step of generating the fabric structure above can generate the fabric structure, which is a meta-structure having a negative Poisson ratio, by repeating (tessellating) the reentrant structure above.

[0014] According to another feature, the fabric actuator is a fabric structure in which pairs of shape memory alloy wires are connected in a two-dimensional direction by repeating a re-entrant structure created through a procedure in which a pair of shape memory alloy wires are knotted in the unit grid of a re-entrant expansion structure, and the pairs of wires of the fabric structure are knotted using a mold to form a single object.

[0015] The above reentrant structure may be a metastructure having a negative Poisson ratio.

[0016] The fabric-type actuator described above has a re-entry structure that is tessellated, so the entire structure can have a negative Poisson ratio.

[0017] The fabric-type actuator described above may have a thin film coating formed on its surface for zone-unit individual current control, in which only some of the multiple divided zones are heated to transmit a contracting force.

[0018] The above thin film coating may include a Parylene coating. Effects of the invention

[0019] According to the embodiment, a fabric-type actuator can be manufactured having a meta-structure that has a negative Poisson ratio and deforms so that it can effectively adhere to human body surfaces having different curvatures and can wrap around all surfaces even in a curved shape. Furthermore, this fabric-type actuator can be applied to a fabric-type wearable haptic device that is lightweight, compact, and easy to wear, such as clothing worn in daily life.

[0020] In addition, by applying a Perlin thin film coating to the surface of the fabric actuator, the force generated by the shape memory alloy through Joule heating via individual current supply to each zone is conveniently and effectively controlled, and a single shape memory alloy-based fabric actuator can be divided into spatially separated zones to provide multiple pieces of information. Brief explanation of the drawing

[0021] FIG. 1 is a flowchart illustrating a method for manufacturing a fabric-type actuator according to one embodiment. FIG. 2 is a diagram illustrating a knotting procedure for manufacturing a fabric-type actuator according to one embodiment. FIG. 3 is a drawing illustrating a non-unraveling knotting method for manufacturing a fabric-type actuator according to one embodiment. FIG. 4 is a drawing illustrating the process of using a mold for manufacturing a fabric-type actuator according to one embodiment. FIG. 5 is an example diagram illustrating spatially separated driving by applying current only to specific areas of a fabric-type actuator coated with Perlin on its surface according to one embodiment. FIG. 6 shows an auxetic-knot shape memory alloy fabric made of an active fabric connected to a passive fabric by a simple sewing according to an embodiment. FIG. 7 illustrates a demonstration of the negative Poisson ratio operation of a fabric type actuator according to one embodiment. FIG. 8 illustrates a demonstration of the shape-fitting function of a fabric actuator according to one embodiment. FIG. 9 illustrates a demonstration of the size-fitting function of a fabric actuator according to one embodiment. FIG. 10 shows a thermal IR image taken after performing individual current control on a fabric actuator according to one embodiment for each divided zone. FIG. 11 shows an application example of a fabric-type actuator according to one embodiment. FIG. 12 shows an application example of a fabric-type actuator according to another embodiment. FIG. 13 shows an application example of a fabric-type actuator according to another embodiment. Specific details for implementing the invention

[0022] Embodiments of the present disclosure are described below with reference to the attached drawings so that those skilled in the art can easily implement them. However, the present disclosure may be embodied in various different forms and is not limited to the embodiments described herein. Furthermore, in order to clearly explain the present disclosure in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification are denoted by similar reference numerals.

[0023] Throughout the specification, when a part is described as "including" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0024] Expressions described in the singular in this specification may be interpreted as singular or plural unless explicit expressions such as "one" or "single" are used.

[0025] In this specification, the same reference numeral refers to the same component regardless of the drawing, and "and / or" includes each of the mentioned components and all combinations of one or more.

[0026] In this specification, terms including ordinal numbers, such as first, second, etc., may be used to describe various components, but said components are not limited by said terms. Such terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the present disclosure, the first component may be named the second component, and similarly, the second component may be named the first component.

[0027] In the flowchart described with reference to the drawings in this specification, the order of operations may be changed, several operations may be merged or some operations may be divided, and certain operations may not be performed.

[0029] FIG. 1 is a flowchart illustrating a method for manufacturing a fabric type actuator according to one embodiment, FIG. 2 is a diagram illustrating a knotting procedure for manufacturing a fabric type actuator according to one embodiment, FIG. 3 is a diagram illustrating a knotting method that does not easily unravel for manufacturing a fabric type actuator according to one embodiment, FIG. 4 is a diagram illustrating a process of utilizing a mold for manufacturing a fabric type actuator according to one embodiment, and FIG. 5 is an example diagram illustrating spatially separated driving by applying current only to a specific area of ​​a fabric type actuator coated with perlin on the surface according to one embodiment.

[0030] Referring to FIG. 1, the manufacturing process of a fabric-type actuator, that is, a fabric-type actuator, consists of S101, S102, S103, and S104.

[0031] In S101, a re-entry structure, which is a unit structure, is created through a procedure of knotting a pair of shape memory alloy wires into the unit cell of a re-entry expansion structure, as described in detail in Fig. 2.

[0032] In S102, by repeating S101, a pair of shape memory alloy wires are extended in the 2D (x-axis, y-axis) direction to produce a fabric-like structure in which multiple pairs of shape memory alloy wires are connected. S102 is explained in detail through FIG. 3.

[0033] In S103, a single fabric actuator is fabricated by knotting pairs of wires using a mold, as illustrated in Fig. 4.

[0034] In S104, a Parylene (Parylene C) coating is applied to the surface of the fabric actuator, as described in detail in Fig. 5.

[0035] Through the above S101, S102, S103, and S104, a fabric actuator in the form of a metastructure having a negative Poisson ratio is fabricated.

[0036] Generally, the Poisson ratio is a value representing the ratio of the strain in the vertical direction to the strain in the parallel direction of an object. A negative Poisson ratio signifies a case where the axis perpendicular to the axis of application of force contracts or expands in the same direction.

[0037] A fabric-type actuator can be fabricated by expanding a shape memory alloy wire in a 2D direction through a series of knotting processes.

[0038] At this time, the unit structure produced through knotting is manufactured to have a 're-entrant structure,' which is one of the meta-structures having a negative Poisson ratio. This unit structure is tessellated to produce a Wearable Haptic Auxetic Fabric (WHAF) in the form of a meta-structure having a negative Poisson ratio.

[0039] Figure 2(a) illustrates the process of creating a re-entrant structure, which is a unit structure, through two shape-memory alloy (SMA) wires (black lines). That is, it shows the procedure of knotting a pair of shape-memory alloy wires into the unit cell of the re-entrant structure. In this way, a pair of shape-memory alloy wires are knotted to form a zone.

[0040] Figures 2(b), (c), and (d) illustrate the process of fabricating a fabric by expanding a pair of shape memory alloy wires in a 2D direction through the process of repeating Figure 2(a).

[0041] At this time, Figure 2(b) shows the process of knotting the shape memory alloy wire into a re-entry structure and expanding it along the y-axis.

[0042] Figure 2(c) shows the process of knotting a shape memory alloy wire into a re-entry structure and extending it along the x-axis.

[0043] Figure 2(d) shows the process of extending the knot along the x-axis and y-axis by repeating Figure 2(b) and (c).

[0044] That is, if you repeat the knotting with a pair of shape memory alloy wires, you create a structure that is extended only in the downward direction, i.e., along the y-axis, as shown in Fig. 2 (b). Therefore, if you add another pair of shape memory alloy wires and attach them sideways to form a knot, you can obtain a structure that is extended sideways, i.e., along the x-axis.

[0045] In this way, a structure that extends in the y-axis direction is produced by knotting a pair of shape memory alloy wires, and a structure that extends in the x-axis is produced by connecting and knotting multiple pairs of shape memory alloy wires. As shown in Fig. 4, when a total of 8 pairs of shape memory alloy wires are knotted, a total of 8 zones are formed.

[0046] At this time, when current is applied to both ends of Zone 1 in Fig. 4, the current does not flow only into Zone 1 but also into adjacent zones, making it impossible to control. The reason for the current flow is that adjacent zones are in physical contact, and since shape memory alloys are conductive materials, current flows when they touch each other. Therefore, if a very thin insulating polymer film is coated on the surface of the shape memory alloy, it is possible to prevent current from flowing into adjacent areas, thereby allowing current to flow only into Zone 1 to which the current is applied. Fig. 3 shows the knotting method used to form a knot that does not easily unravel during the knotting process of Fig. 2 (a), (b), (c), and (d). That is, Fig. 3 shows the process of knotting two shape memory alloy wires emerging from adjacent pillars that share vertices and corners.

[0047] Figure 4 illustrates the process of using a mold to knot shape memory alloy wires and thereby fabricating a fabric-type actuator of a meta-structure. Specifically, it illustrates the process of fabricating a fabric-type actuator as a single unit by knotting eight pairs of shape memory alloy wires.

[0048] Custom aluminum molds are used as frames to hold the structure in place during the shape memory process. The wire pairs constituting the pillars of the fabric actuator are distinguished by different colors, and each wire pair is color-matched.

[0049] The fabric actuator, formed using a mold, undergoes a process of heating at a high temperature of 390° for one hour and rapidly cooling in cold water a total of three times for the shape memory process.

[0050] To explain in more detail, it is as follows.

[0051] According to Figure 2(a), the unit cell of the re-entry structure has six vertices connected by six corners, resembling a bow tie shape. Two shape memory alloy wires (indicated as 1 and 1') are used to form this unique shape through knots.

[0052] First, shape memory alloy wires are intersected to form the first vertex in the center, and then the two wires are separated to the left and right respectively to form the upper part of the angle expansion unit. Next, an additional vertex is knotted in the lower half, and then the two wires are gathered and knotted in the center to finally form a single unit grid in the shape of an angle.

[0053] According to Figure 2(b), if the two wires coming out of the last vertex are twisted and the same process is repeated, the entire structure can be expanded in one direction, namely the y-axis or the vertical direction.

[0054] According to Fig. 2(c), to expand the structure along another axis, namely the x-axis, a pair of shape memory alloy wires is knotted to form a re-entrant structure in which adjacent auxiliary lattices share two vertices and one edge. Then, by repeating the process of forming an expansion structure along the x-axis and y-axis, an expanded shape memory alloy wire fabric expanded in the 2D direction can be produced, as shown in Fig. 2(d).

[0055] Meanwhile, all vertices realized by knotting shape memory alloy wires are designed to function as static points with high structural integrity during repetitive operation and deformation. According to FIG. 2, to ensure robust structural integrity, the vertex knotting is performed in three stages: 1. interlacing, 2. forming a square knot, and 3. tightening with the addition of forming a so-called double square knot. Through these three consecutive stages, three friction points are created during each interlacing process, thereby maintaining the shape of the vertex robustly even in the event of deformation, and allowing the robust vertex to function as an undeformed static point.

[0056] Referring to Fig. 4, to form the expansion fabric of Fig. 2, the shape memory alloy wire is knotted using an aluminum mold with pillars that act as pinpoints where knotted vertices are created.

[0057] The entire interlacing and knotting procedure, consisting of the four specific steps mentioned above, is illustrated in Figures 2, 3, and 4, respectively.

[0058] A fabric actuator (WHAF) having an auxetic structure knot is fabricated by repeating the cross-linking and knotting of shape memory alloy wires in four stages at a specific part.

[0059] Referring to FIG. 5, Parylene is coated on the surface of a fabric actuator for spatially separated zone-based drive control. That is, a thin Parylene (Parylene C) coating with a thickness of 5 micrometers can be applied to the surface of the fabric actuator to enable individual drive for each zone of a single shape memory alloy-based fabric actuator, which is spatially separated. Through this, the conductive surface of the shape memory alloy is insulated, thereby suppressing the phenomenon in which current flows to adjacent areas during the Joule heating process through current supply, causing unwanted areas to be heated and contracted.

[0060] This Perlin coating process is performed via Chemical Vapor Deposition (CVD), which enables a uniform and robust coating even on surfaces with complex and tight structures.

[0061] Perlin is an insulator, and perlin coating using CVD, that is, a coating method through gas injection, can be uniformly coated even in very small gaps. Therefore, when a perlin coating is applied to the surface of a shape memory alloy, a perlin thin film can be coated without missing any gaps in the knotted structure, and as a result, current can be prevented from flowing between zones, making it possible to control current by zone.

[0062] According to Fig. 5, when current is applied to only a portion of a shape memory alloy-based fabric actuator with a Perlin coating, current does not flow in adjacent areas but flows only in a specific area, so that force is generated and contraction occurs only in that area.

[0063] Through the above process, it is possible to produce a fabric-type actuator of a metastructure having a negative Poisson ratio, in which a shape memory alloy wire is knotted and expanded into a 2D fabric form, and the final formed shape formed by knotting has a re-entrant structure that is a metastructure having a negative Poisson ratio, and finally the re-entrant structure is tessellated so that the entire structure has a negative Poisson ratio.

[0064] In addition, by applying a Perlin thin film coating to the surface of a fabric actuator, surface conductivity modification and zone-specific driving control are made possible. Therefore, the fabric actuator can be controlled easily and effectively through current control, and various spatial information essential for haptic applications can be provided.

[0066] FIG. 6 shows an auxetic-knot shape memory alloy fabric made of an active fabric connected to a passive fabric by a simple sewing according to an embodiment.

[0067] Referring to FIG. 6, the meta-structure fabric actuator having a negative Poisson ratio described in FIGs. 1 to 5 can be combined with ordinary fabrics through simple sewing to be applied as a wearable device and produced as an active smart garment.

[0068] The enlarged image with the red outline shows how shape memory alloy wires intersect and knot to form a tile pattern of the re-entry structure.

[0069] The enlarged image with the blue outline shows how the edges of the active fabric are stitched or sewn together with the passive fabric.

[0071] FIG. 7 illustrates a demonstration of the negative Poisson ratio operation of a fabric type actuator according to one embodiment.

[0072] Referring to FIG. 7(a), an image is shown of the fabric actuator before it is extended laterally. At this time, the total dimensions of the fabric actuator are measured as “80×75mm”.

[0073] Referring to Fig. 7(b), the image shows the fabric actuator after it has been extended laterally, at which point the total dimensions of the fabric actuator are measured as “155×90mm”.

[0074] The calculated negative Poisson ratio is calculated as in Equation 1.

[0075] [Mathematical Formula 1]

[0076]

[0077] Referring to Figure 7 (c), the sequence of extending the fabric actuator inward (direction of the red arrow) and the comparison before and after inward extension (blue arrow) are shown.

[0078] Through the operation demonstration in Fig. 7, it can be seen that when one axis is deformed (relaxed), the same deformation (relaxation) occurs on the other axis. Thus, a metastructure having a negative Poisson ratio can effectively adhere as the structure adapts and changes according to the curvature of the curved surface.

[0080] FIG. 8 illustrates a demonstration of the shape-fitting function of a fabric actuator according to one embodiment, and FIG. 9 illustrates a demonstration of the size-fitting function of a fabric actuator according to one embodiment.

[0081] Referring to FIG. 8(a), it shows a fabric actuator completely covering a sphere with a radius (R) of 1.9 mm. Referring to FIG. 8(b), it shows a fabric actuator completely covering a spherical globe with a radius (R) of 3 mm. Referring to FIG. 8(c), it shows a fabric actuator in close contact with the ellipsoidal surface of a soccer ball.

[0082] FIG. 9(a) shows an oblique view of a fabric actuator that has been contracted and rolled in the 3D direction after heating, FIG. 9(b) shows a front view, and FIG. 9(c) shows a side view.

[0083] As shown in Fig. 9, when a 2D fabric actuator is rolled into a cylindrical shape for use, it can be seen to contract or expand in the 3D direction. Therefore, the fabric actuator can be applied as a structure that actively adapts to the wearer's body size.

[0085] FIG. 10 shows a thermal IR image taken after performing individual current control on a fabric actuator according to one embodiment for each divided zone.

[0086] Referring to Fig. 10, when heating in line units through zone-specific individual current control, only a specific zone is heated, and a contracting force is transmitted only to that zone. The heating process is recorded through a thermal imaging camera to acquire a thermal IR image. Through zone-specific individual current control, nine different types of information can be transmitted to the wearer and used to indicate direction.

[0087] No. 1 is a thermal IR image taken after applying current only to the left area and heating it to shrink it, which can be used as information indicating the left direction (Left, L).

[0088] No. 2 is a thermal IR image taken after applying current only to the central area and heating it to shrink it, which can be used as information indicating the forward direction.

[0089] No. 3 is a thermal IR image taken after applying current only to the right section and heating it to shrink it, which can be used as information indicating the right direction (Right, R).

[0090] No. 4 is a thermal IR image taken after applying current only to the central and left regions and heating to shrink it, which can be used as information pointing to the left (L-45°) in a 45° diagonal direction.

[0091] No. 5 is a thermal IR image taken after applying current only to the left section of No. 1 and the right section of No. 3 and heating to shrink it, which can be used as information to indicate stopping.

[0092] No. 6 is a thermal IR image taken after applying current only to the center and right zones and heating to shrink it, which can be used as information pointing to the right (R-45°) in a 45° diagonal direction.

[0093] No. 7 is a thermal IR image taken after applying current to the right, center, and left sections sequentially at 0.5-second intervals and heating to contract, and can be used to simultaneously convey information about the direction indicating the left and the timing indicating the start of movement.

[0094] Number 8 is a thermal IR image taken after applying current to the left, center, and right sections sequentially at 0.5-second intervals and heating to contract them, and can be used to simultaneously convey information about the direction indicating the right and the timing indicating the start of movement.

[0095] No. 9 is a thermal IR image taken after applying current to the entire area (Total Squeeze) and heating to shrink it.

[0096] In this way, according to FIG. 10, by applying current only to specific areas and heating to shrink them through individual current control for each area, when a fabric actuator is applied as a wearable haptic device, information about space and timing can be intuitively provided to the wearer.

[0098] FIG. 11 shows an application example of a fabric type actuator according to one embodiment, FIG. 12 shows an application example of a fabric type actuator according to another embodiment, and FIG. 13 shows an application example of a fabric type actuator according to yet another embodiment.

[0099] Referring to FIGS. 11 and 12, a wearable haptic device made of a fabric-type actuator according to an embodiment can be worn in close contact with the wrist.

[0100] The wearable haptic device is manufactured using the aforementioned shape memory alloy-based metastructure fabric actuator (Auxetic knotted-SMA), adjustable strap, and band. Through this, in cases where both hands cannot be used as shown in FIG. 12, for example, when both hands must be fixed to the handle while riding a mobile device, the wearable haptic device can be applied to enable movement through directional information transmitted to the wrist without separate announcements or navigation checks.

[0101] Referring to FIG. 13, the wearable haptic device can be applied as a wearable haptic device that intuitively conveys information about direction and surrounding space to the wrist under limited visual information when remotely controlling robots and transport devices within a VR environment, such as controlling a Mars probe, through compatibility with virtual reality (VR) devices and VR environments. A situation in which visibility is limited due to strong sandstorms caused by the deterioration of the atmospheric environment on Mars can be implemented in virtual reality (VR), and information about obstacles in front, to the side, and behind the Mars probe can be conveyed through the wearable haptic device. Through this, it can be used for training an operator controlling a Mars probe under adverse conditions with limited visibility, or for actual control of a Mars probe.

[0103] Although embodiments of the present disclosure have been described in detail above, the scope of the present disclosure is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concepts of the present disclosure as defined in the following claims also fall within the scope of the present disclosure.

Claims

Claim 1 A manufacturing method comprising: a step of creating a re-entrant structure, which is a unit structure, by tying a pair of shape memory alloy wires to form a single zone through a procedure of tying a pair of shape memory alloy wires to a unit grid of a re-entrant expansion structure; a step of creating a fabric structure in which pairs of shape memory alloy wires are extended and connected in a two-dimensional direction by repeating (tessellation) the step of creating the re-entrant structure using a plurality of pairs of shape memory alloy wires; a step of manufacturing a fabric-type actuator of a single object by tying the pairs of wires of the fabric structure using a mold; and a step of forming a film membrane on the surface of the fabric-type actuator, wherein the film membrane insulates the conductive shape memory alloy surface and suppresses the flow of current to adjacent zones other than a specific zone into which current flows through the insulation, thereby enabling individual current control of the fabric-type actuator in units of a plurality of zones. Claim 2 In claim 1, the re-entry structure is a manufacturing method in which the shape formed through the knotting procedure has a negative Poisson ratio. Claim 3 A manufacturing method according to claim 1, wherein the film layer is formed on the surface of the fabric-type actuator using Chemical-Vapor Deposition (CVD). Claim 4 In paragraph 2, the manufacturing method wherein the film layer is produced by performing a Parylene coating on the surface of the fabric-type actuator. Claim 5 A manufacturing method according to claim 1, wherein the step of generating the fabric structure comprises generating the fabric structure, which is a meta-structure having a negative Poisson ratio, by repeating (tessellating) the re-entrant structure. Claim 6 A fabric actuator comprising a pair of shape memory alloy wires knotted into a unit grid of a re-entrant expansion structure to form a single zone, a fabric structure formed by the unit grid being tessellated and connected in a two-dimensional direction through a plurality of pairs of shape memory alloy wires, and a film formed on the surface of the fabric structure, wherein the fabric structure forms a single object by knotting the pairs of wires using a mold, and the film insulates the conductive shape memory alloy surface of the fabric structure and suppresses the flow of current to adjacent zones other than a specific zone into which current flows through the insulation, thereby enabling individual current control on a zone-by-zone basis. Claim 7 In paragraph 6, the above-mentioned re-entry structure is a fabric actuator, which is a meta-structure having a negative Poisson ratio. Claim 8 In claim 7, a fabric actuator in which the above-mentioned re-entry structure is repeated (tessellated) so that the overall structure has a negative Poisson ratio. Claim 9 delete Claim 10 In claim 6, the above film is a fabric actuator formed through a Parylene coating.

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