A microstructure flexible pressure sensor based on fold evolution and a design method thereof

Abstract

This invention belongs to the field of flexible sensor technology and discloses a microstructure flexible pressure sensor based on crease evolution and its design method. The sensor includes an upper electrode, a lower electrode, and a sensitive layer located between them. The sensitive layer consists of a flat plate and multiple microstructure units. Each microstructure unit is a polyhedral structure, including a basic unit and its derived units, designed using a crease evolution strategy. The design method includes: unfolding the basic unit into a two-dimensional crease; analyzing its geometric features; generating derived creases through an amplification or reduction similarity evolution strategy; and then folding it into a three-dimensional microstructure unit. This invention, through a systematic design method and innovative crease evolution technology, solves the randomness problem in the design of microstructure flexible pressure sensors, significantly improving the sensor's performance and reliability, and has significant theoretical value and practical application significance.

Description

Technical Field

[0001] This invention belongs to the field of flexible sensor technology, and in particular relates to a microstructure flexible pressure sensor based on crease evolution and its design method. Background Technology

[0002] Flexible pressure sensors, which help soft robots perceive changes in contact pressure, are an indispensable part of intelligent flexible systems. With the continuous development of intelligent requirements, higher demands are being placed on the performance indicators of flexible pressure sensors, such as wide operating range, high linearity, and customizable sensitivity. More research focuses on various strategies aimed at improving sensing performance, among which the micron-level morphological structure design of the sensitive layer or electrode layer is considered a promising method for improving the performance of flexible pressure sensors. For example, this can be achieved by controllably introducing microstructures with highly regular shapes (such as pyramids or micro-hemisphers) or replicating naturally occurring microstructural templates (such as pollen grains, petals, human skin, and sandpaper) to introduce them into the active layer of the flexible pressure sensor. However, these methods lack clear guidance based on rational design, leading to a randomness in the achievement of target performance. Therefore, it is necessary to introduce deterministic microstructure design methods and further determine the morphological and spatial parameters based on appropriate theoretical calculations. Summary of the Invention

[0003] The purpose of this invention is to provide a microstructure flexible pressure sensor and design method based on crease evolution, so as to solve the technical problem that the existing microstructure design methods of flexible pressure sensors lack clear guidance based on rational design, resulting in randomness in the design.

[0004] To address the aforementioned technical problems, the specific technical solution of this invention, a microstructure flexible pressure sensor based on crease evolution and its design method, is as follows:

[0005] A microstructure flexible pressure sensor based on crease evolution includes a sensitive layer comprising a plate and a series of microstructure units. Each microstructure unit is connected by the plate. The microstructure unit is a series of polyhedral units with polygonal bases, isosceles triangles on the sides, and points at vertices. The polyhedral units are obtained from the basic units based on a derivation design method.

[0006] Furthermore, the microstructure flexible pressure sensor also includes an upper electrode and a lower electrode, the sensitive layer is connected between the upper electrode and the lower electrode, and the upper electrode and the lower electrode are wrapped with an encapsulation layer.

[0007] Furthermore, the upper and lower electrodes are made of conductive materials.

[0008] Furthermore, the sensitive layer is an ion-conductive hydrogel material composed of polyvinyl alcohol and anhydrous magnesium chloride, or a PDMS elastomer doped with conductive materials.

[0009] Furthermore, the polyhedral unit, when its base is a regular quadrilateral and its lateral isosceles triangles are equilateral triangles, is defined as a 4-1 type basic unit, where 4 represents the number of vertices of the base polygon and 1 represents the number of vertices; the polyhedral unit, when its base is a regular quadrilateral and its lateral isosceles triangles have a height-to-base ratio greater than 1 / 2... When defined as a 4-1 type derivative unit, 4 represents the number of vertices of the base polygon, and 1 represents the number of vertices; the polyhedral unit, when its base is a regular quadrilateral and the ratio of the height to the base of its isosceles triangle is less than 1 / 3. When the base polygon is an octagon and the lateral faces are eight isosceles triangles, the polyhedral unit is defined as a 4-1 type II derivative unit, where 4 represents the number of vertices of the base polygon and 1 represents the number of vertices. When the base polygon is an octagon and the lateral faces are eight isosceles triangles, the polyhedral unit is defined as an 8-1 type derivative unit, where 8 represents the number of vertices of the base polygon and 1 represents the number of vertices. The 4-1 type I derivative unit, the 4-1 type II derivative unit, and the 8-1 type derivative unit are obtained from the 4-1 type basic unit based on the derivative design method.

[0010] This invention also discloses a microstructure unit derivation design method for a microstructure flexible pressure sensor based on crease evolution, comprising the following steps:

[0011] Step 1: Unfold the 4-1 type basic unit along the edge, reducing it from three dimensions to two dimensions, to obtain a two-dimensional crease diagram with a regular quadrilateral in the center and four isosceles triangles around it. Define this as a two-dimensional basic crease.

[0012] Step 2: Analyze the geometric features of the two-dimensional basic creases. Define the circumcircle of the regular quadrilateral and the circumcircles of the four isosceles triangles as the basic circles. All the surrounding basic circles are tangent to the two adjacent basic circles, and the point of tangency is the vertex of the central regular quadrilateral.

[0013] Step 3: Based on the similarity evolution strategy, the two-dimensional basic crease evolves to obtain the two-dimensional 4-1 type I derived crease, the two-dimensional 4-1 type II derived crease, and the two-dimensional 8-1 type derived crease;

[0014] Step 4: Fold the two-dimensional derivative creases along the sides of the quadrilateral or octagon to obtain the 4-1 type I derivative unit, the 4-1 type II derivative unit, and the 8-1 type derivative unit.

[0015] Furthermore, the two-dimensional 4-1 type-1 derived crease mentioned in step 3 is obtained from the two-dimensional basic crease through an amplification and similarity evolution strategy that takes the inner intersection point. The two-dimensional 4-1 type-1 derived crease includes a regular quadrilateral and four isosceles triangles whose base sides coincide with the sides of the regular quadrilateral. The amplification and similarity evolution strategy that takes the inner intersection point is based on the basic circle in the two-dimensional basic crease. Without changing the position of the center of the basic circle, the radius of the basic circle is simultaneously enlarged to obtain a new enlarged derived basic circle. Adjacent derived basic circles intersect each other at two intersection points, one inside and one outside. P in and P out Select four internal intersection points P in The base quadrilateral of the 4-1 type derived polyhedron unit is obtained by connecting them sequentially. A perpendicular bisector is drawn on each side of the base quadrilateral. The far-distance intersection of the perpendicular bisector with the four enlarged derived base circles is taken as the vertex of the lateral isosceles triangle. The four isosceles triangles are obtained by connecting them sequentially.

[0016] Furthermore, the two-dimensional 4-1 type II derived crease mentioned in step 3 is obtained from the two-dimensional basic crease through an amplification and similarity evolution strategy using the diplomatic point. The two-dimensional 4-1 type II derived crease includes a regular quadrilateral and four isosceles triangles whose base sides coincide with the sides of the regular quadrilateral. The amplification and similarity evolution strategy using the diplomatic point is based on the basic circle in the two-dimensional basic crease. Without changing the position of the center of the basic circle, the radius of the basic circle is simultaneously enlarged to obtain a new enlarged derived basic circle. Adjacent derived basic circles intersect each other at two intersection points, one inside and one outside. P in and P out Select four diplomatic points P out The base quadrilateral of the 4-1 type II derived polyhedron unit is obtained by connecting them sequentially. A perpendicular bisector is drawn on each side of the base quadrilateral. The far-distance intersection of the perpendicular bisector with the four enlarged derived base circles is taken as the vertex of the isosceles triangle on the side. The four isosceles triangles are obtained by connecting them sequentially.

[0017] Furthermore, the two-dimensional 8-1 type derived crease mentioned in step 3 is obtained from the two-dimensional basic crease through a reduction similarity evolution strategy. The two-dimensional 8-1 type derived crease includes an octagon and eight isosceles triangles whose base sides coincide with the sides of the octagon. The reduction similarity evolution strategy is based on the basic circle in the two-dimensional basic crease. Without changing the position of the center of the basic circle, the radius of the basic circle is reduced simultaneously to obtain new, mutually disjoint reduced derived basic circles. Connecting the centers of the reduced derived basic circles yields a regular quadrilateral. The intersection of the regular quadrilateral and the reduced derived basic circles yields eight... Intersection points: Connect the eight intersection points in sequence to obtain an octagon of type 8-1 derived crease. Draw the perpendicular bisectors of the four sides of the octagon that are inside the reduced derived base circle. Take the farthest intersection point of the perpendicular bisector with the four reduced derived base circles as the vertices of the four isosceles triangles on the sides. Connect them in sequence to obtain four isosceles triangles. With the eight vertices of the octagon as the center, draw arcs with the side lengths of the four isosceles triangles obtained above as the radius. The intersection points of adjacent arcs are used as the vertices of the remaining four isosceles triangles. Connect them in sequence to obtain the remaining four isosceles triangles of the two-dimensional type 8-1 derived crease.

[0018] The microstructure flexible pressure sensor and design method based on crease evolution of the present invention have the following advantages:

[0019] Systematic Design Method: This invention provides a design method for a microstructure flexible pressure sensor based on crease evolution. Through a parameterized geometric model and a clear crease evolution strategy, it achieves rational design of microstructure units, avoiding the randomness and blindness in traditional design.

[0020] Diverse microstructure units: By combining basic units and derived units (such as 4-1 type I, 4-1 type II and 8-1 type), polyhedral microstructures with different contact deformation characteristics can be flexibly designed to meet the sensor performance requirements of different application scenarios.

[0021] High-performance sensing characteristics: The designed microstructure flexible pressure sensor exhibits high sensitivity and stability under pressure, the resistance change rate changes significantly with increasing pressure, and it shows good repeatability and recoverability in cyclic pressure testing.

[0022] Structural optimization and computational support: Through precise geometric parameter calculation formulas, key parameters such as the height and side length of microstructure units can be optimized, thereby achieving precise control over the sensor's sensitivity, linearity, and operating range.

[0023] Innovative crease evolution technology: Introducing crease evolution strategies from origami techniques provides new ideas for microstructure design, which not only simplifies the manufacturing process but also improves the controllability and consistency of microstructures.

[0024] With broad application prospects, this design method is applicable to fields such as soft robots, smart wearable devices, and medical monitoring, providing reliable technical support for the development of flexible electronic devices.

[0025] In summary, this invention solves the randomness problem in the design of microstructure flexible pressure sensors through a systematic design method and innovative crease evolution technology, significantly improving the performance and reliability of the sensor, and has important theoretical value and practical application significance. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the microstructure flexible pressure sensor of the present invention.

[0027] Figure 2 This is a schematic diagram of the 4-1 type basic unit of the present invention and the two-dimensional basic crease structure obtained by unfolding it.

[0028] Figure 3 This is a schematic diagram of the 4-1 type derivative unit structure obtained by the two-dimensional 4-1 type derivative crease and folding of the present invention.

[0029] Figure 4 This is a schematic diagram of the 4-1 type II derivative unit structure obtained by the two-dimensional 4-1 type II derivative crease and folding of the present invention.

[0030] Figure 5 This is a schematic diagram of the 8-1 type derivative unit structure obtained by the two-dimensional 8-1 type derivative crease and folding according to the present invention.

[0031] Figure 6 The graph shows the response and recovery curves of the microstructure flexible pressure sensor of the present invention under different pressures, where (R-R0) / R0 represents the resistance change rate of the sensor.

[0032] Figure 7 The graph shows the cyclic test curve of the microstructure flexible pressure sensor of the present invention under a pressure of 4255 Pa, where (R-R0) / R0 represents the resistance change rate of the sensor.

[0033] The markings in the diagram are as follows: 1. Upper electrode; 2. Lower electrode; 3. Sensitive layer; 31. Plate; 32. Microstructure unit; 4. Encapsulation layer. Detailed Implementation

[0034] To better understand the purpose, structure, and function of this invention, the following detailed description, in conjunction with the accompanying drawings, provides a microstructure flexible pressure sensor based on crease evolution and its design method.

[0035] like Figure 1As shown, a microstructure flexible pressure sensor based on crease evolution according to the present invention includes an upper electrode 1 and a lower electrode 2, with a sensitive layer 3 between the upper electrode 1 and the lower electrode 2. The upper and lower ends of the sensitive layer 3 are connected to the upper electrode 1 and the lower electrode 2, respectively. The sensitive layer 3 includes a plate 31 and a series of microstructure units 32, each microstructure unit 32 being connected through the plate 31. The upper electrode 1 and the lower electrode 2 are wrapped with polyimide tape as an encapsulation layer 4.

[0036] The upper electrode 1 and the lower electrode 2 can be made of conductive materials such as copper, gold, or conductive glass.

[0037] The sensitive layer 3 can be an ion-conductive hydrogel material made of a mixture of polyvinyl alcohol and anhydrous magnesium chloride, or a PDMS elastomer doped with conductive materials such as graphene or carbon nanotubes.

[0038] The microstructure unit 32 of the sensitive layer 3 is a series of polyhedral units with polygonal bases, isosceles triangles on the sides and points at the vertices.

[0039] The polyhedral unit, when its base is a regular quadrilateral and its lateral isosceles triangles are equilateral triangles, is defined as a 4-1 type basic unit, where 4 represents the number of vertices of the base polygon and 1 represents the number of vertices.

[0040] The polyhedral unit, when its base is a regular quadrilateral and its lateral face is an isosceles triangle, has a height-to-base ratio greater than... When defined as a 4-1 type derivative unit, 4 represents the number of vertices of the base polygon and 1 represents the number of vertices.

[0041] The polyhedral unit, when its base is a regular quadrilateral and its lateral surface is an isosceles triangle, has a height-to-base ratio less than [value missing]. When defined as a 4-1 type II derivative unit, 4 represents the number of vertices of the base polygon and 1 represents the number of vertices.

[0042] The polyhedral unit, when its base is an octagon and its lateral faces are eight isosceles triangles, is defined as an 8-1 type derived unit, where 8 represents the number of vertices of the base polygon and 1 represents the number of vertices.

[0043] The 4-1 type I derivative unit, 4-1 type II derivative unit, and 8-1 type derivative unit are obtained from the 4-1 type basic unit based on the derivative design method.

[0044] The present invention provides a method for the derivation design of sensitive layer microstructure units based on crease evolution, the specific steps of which are as follows:

[0045] Step 1: Unfold the 4-1 type basic unit along the edge, reducing it from three dimensions to two dimensions, to obtain a two-dimensional crease diagram with a regular quadrilateral in the center and four isosceles triangles around it. Define this as a two-dimensional basic crease.

[0046] Step 2: Analyze the geometric features of the two-dimensional basic creases. Define the circumcircle of the regular quadrilateral and the circumcircles of the four isosceles triangles as the basic circles. All the surrounding basic circles are tangent to the two adjacent basic circles, and the point of tangency is the vertex of the central regular quadrilateral.

[0047] Step 3: Based on the similarity evolution strategy, the two-dimensional basic crease is evolved to obtain the two-dimensional 4-1 type I derivative crease, the two-dimensional 4-1 type II derivative crease and the two-dimensional 8-1 type derivative crease.

[0048] The two-dimensional 4-1 type-1 derived crease is obtained from the two-dimensional basic crease through an amplified similarity evolution strategy that takes the inner intersection point. The two-dimensional 4-1 type-1 derived crease includes a regular quadrilateral and four isosceles triangles whose base sides coincide with the sides of the regular quadrilateral.

[0049] The aforementioned amplified similarity evolution strategy, which takes the inner intersection point as the basis, uses the base circle in the two-dimensional base crease as the foundation. Without changing the position of the center of the base circle, the radius of the base circle is simultaneously enlarged to obtain a new amplified derived base circle. Adjacent derived base circles intersect each other at two intersection points, one inside and one outside. P in and P out Select four internal intersection points P in The base quadrilateral of the 4-1 type derived polyhedron unit is obtained by connecting them sequentially. A perpendicular bisector is drawn on each side of the base quadrilateral. The far-distance intersection of the perpendicular bisector with the four enlarged derived base circles is taken as the vertex of the lateral isosceles triangle. The four isosceles triangles are obtained by connecting them sequentially.

[0050] The two-dimensional 4-1 type II derived crease is obtained from the two-dimensional basic crease through an amplified similarity evolution strategy using diplomatic points. The two-dimensional 4-1 type II derived crease includes a regular quadrilateral and four isosceles triangles whose bases coincide with the sides of the regular quadrilateral.

[0051] The aforementioned strategy of amplifying similarity evolution based on the diplomatic point takes the basic circle in the two-dimensional basic crease as the basis, and simultaneously enlarges the radius of the basic circle without changing the position of the center of the basic circle to obtain a new amplified derived basic circle. Adjacent derived basic circles intersect each other at two intersection points, one inside and one outside. P in and P out Select four diplomatic points P out The base quadrilateral of the 4-1 type II derived polyhedron unit is obtained by connecting them sequentially. A perpendicular bisector is drawn on each side of the base quadrilateral. The far-distance intersection of the perpendicular bisector with the four enlarged derived base circles is taken as the vertex of the isosceles triangle on the side. The four isosceles triangles are obtained by connecting them sequentially.

[0052] The two-dimensional 8-1 type derived crease is obtained from the two-dimensional basic crease through a reduction similarity evolution strategy. The two-dimensional 8-1 type derived crease includes an octagon and eight isosceles triangles whose base sides coincide with the sides of the octagon.

[0053] The shrinking similarity evolution strategy uses the base circle in the two-dimensional basic crease as a foundation. Without changing the center position of the base circle, the radius of the base circle is simultaneously reduced to obtain new, mutually disjoint, reduced derivative base circles. Connecting the centers of the reduced derivative base circles yields a regular quadrilateral. The regular quadrilateral intersects the reduced derivative base circles at eight points. Connecting these eight points sequentially yields an octagon for the 8-1 type derivative crease. The perpendicular bisectors of the four sides of the octagon located within the reduced derivative base circles are drawn. The farthest intersections of these perpendicular bisectors with the four reduced derivative base circles are taken as the vertices of four isosceles triangles on the lateral faces. Connecting these points sequentially yields four isosceles triangles. Using the eight vertices of the octagon as centers and the side lengths of the four isosceles triangles as radii, arcs are drawn. The intersections of adjacent arcs are taken as the vertices of the remaining four isosceles triangles. Connecting these arcs sequentially yields the remaining four isosceles triangles of the two-dimensional 8-1 type derivative crease.

[0054] Step 4: Fold the two-dimensional derivative creases along the sides of the quadrilateral or octagon to obtain the 4-1 type I derivative unit, the 4-1 type II derivative unit, and the 8-1 type derivative unit. Example

[0055] like Figure 2 As shown, by unfolding the 4-1 type basic unit along its edges, reducing it from three dimensions to two dimensions, a square with its center is obtained. □M 1 M 2 M 3 M 4 The surrounding area consists of four isosceles triangles. △M 1 A 1 M 2 , △M 2 A 2 M 3 , △M 3 A 3 M 4 , △M 4 A 4 M 1The two-dimensional crease diagram of ) is defined as a two-dimensional basic crease, and its geometric characteristics are analyzed:

[0056] 1) Define the circumcircle of the regular quadrilateral and the circumcircles of the four isosceles triangles as the basic circles, denoted as . O ( O 0 , O 1 , O 2 , O 3 , O 4 , R ),in, R Based on the radius of the basic circle, O 0 , O 1 , O 2 , O 3 , O 4 The center of the basic circle is such that all surrounding basic circles are tangent to the two adjacent basic circles at the vertices of the central regular quadrilateral. M 1 , M 2 , M 3 , M 4 The interior angles of a regular quadrilateral are denoted as . Side length is recorded as and the radius of the basic circle R Satisfying Relationship:

[0057] ,

[0058] 2) The height of the 4-1 type basic unit is defined as follows: The height of the side surface of the 4-1 type basic unit (i.e., the isosceles triangle in the two-dimensional foundation fold) is defined as... The asymmetry between the center and the edge is defined as follows: It can be calculated using the following formula:

[0059]

[0060] like Figure 3 As shown, based on the basic circle in the two-dimensional basic crease, without changing the position of the center of the basic circle, the radius of the basic circle is simultaneously enlarged to obtain a new enlarged derived basic circle. O E ( O 0 , O 1 ,O 2 , O 3 , O 4 , R E Define the radius of the new enlarged derived basic circle. R E Compared with the radius of the basic circle before evolution R The ratio is the similarity ratio. w Adjacent enlarged derivative basic circles intersect each other at two points, one inside and one outside. P in and P out Select the enlarged derivative base circle O E The four internal intersections P in And by connecting them sequentially, we obtain a quadrilateral with a type 4-1 derived crease. M 1 M 2 M 3 M 4 Draw a perpendicular bisector on each side of the quadrilateral, and take the farthest intersection point of the perpendicular bisector with the four enlarged derivative base circles. A 1 , A 2 , A 3 , A 4 ), connected sequentially M 1 A 1 , A 1 M 2 , M 2 A 2 , A 2 M 3 ，M 3 A 3 , A 3 M 4 , M 4 A 4 , A 4M 1 This yields four isosceles triangles. Folding these isosceles triangles along the creases results in the 4-1 type derivative unit. M 1 M 2 M 3 M 4 -A .

[0061] 4-1 Type I Derivative Unit Base Square Side Length , and similarity ratio w and the side length of the base of the basic unit The relationship is:

[0062]

[0063] 4-1 Type I Derivative Unit Side Height and the distance between the center and the edge It can be calculated using the following formula:

[0064]

[0065] The height of the 4-1 type-1 derived unit can be calculated using the above formula. :

[0066]

[0067] like Figure 4 As shown, based on the basic circle in the two-dimensional basic crease, without changing the position of the center of the basic circle, the radius of the basic circle is simultaneously enlarged to obtain a new enlarged derived basic circle. O E ( O 0 , O 1 , O 2 , O 3 , O 4 , R E Adjacent enlarged derivative base circles intersect each other at two points, one inside and one outside. P in and P out Select the enlarged derivative base circle O E Four diplomatic points P out And by connecting them sequentially, we obtain the quadrilateral with the type II derived crease 4-1. M1 M 2 M 3 M 4 Draw a perpendicular bisector on each side of the quadrilateral, and take the farthest intersection point of the perpendicular bisector with the four enlarged derivative base circles. A 1 , A 2 , A 3 , A 4 ), connected sequentially M 1 A 1 , A 1 M 2 , M 2 A 2 , A 2 M 3 ，M 3 A 3 , A 3 M 4 , M 4 A 4 , A 4 M 1 This yields four isosceles triangles. Folding these isosceles triangles along the creases results in the 4-1 type II derived unit. M 1 M 2 M 3 M 4 -A .

[0068] 4-1 Side length of the regular quadrilateral base of the type II derivative unit , and similarity ratio w and the side length of the base of the basic unit The relationship is:

[0069]

[0070] 4-1 Type II Derivative Unit Lateral Height and the distance between the center and the edge It can be calculated using the following formula:

[0071]

[0072] The element height of the 4-1 type II derived element can be calculated using the above formula. :

[0073]

[0074] like Figure 5 As shown, based on the basic circle in the two-dimensional basic crease, without changing the position of the center of the basic circle, the radius of the basic circle is simultaneously reduced to obtain new, mutually disjointed reduced derivative basic circles. O S ( O 0 , O 1 , O 2 , O 3 , O 4 , R S Connect the centers of the reduced base circle to obtain a regular quadrilateral. O 1 O 2 O 3 O 4 Regular quadrilateral and its reduced derivative basic circle O S ( O 0 , O 1 , O 2 , O 3 , O 4 , R S The intersections yield eight points. M 1 , M 2 … M 7 , M 8 Connect the eight intersection points in sequence to obtain the base octagon of the 8-1 type derived crease. Draw the perpendicular bisectors of the four sides of the base octagon that lie inside the reduced base circle. Take the farthest intersection points of the perpendicular bisectors with the four reduced derived base circles. A1 , A 3 , A 5 , A 7 ), connected sequentially M 1 A 1 , A 1 M 2 , M 3 A 3 , A 3 M 4 , M 5 A 5 , A 5 M 6 , M 7 A 7 , A 7 M 8 This yields four isosceles triangles on the lateral sides of the 8-1 type derived crease, with the length of the base denoted as . At this point, the four isosceles triangles on the sides and the octagon on the base cannot be folded to form a closed derivative unit. Using the eight vertices of the octagon as centers, and the side lengths (i.e., line segments) of the four isosceles triangles on the sides... M 1 A 1 Draw an arc with a radius of (length), and the intersection of adjacent arcs ( A 2 , A 4 , A 6 , A 8 ( ) serves as the vertex of the remaining isosceles triangle of the 8-1 type derived crease. Connect sequentially... M 2 A 2 , A 2 M 3 , M 4 A 4, A 4 M 5 , M 6 A 6 , A 6 M 7 , M 8 A 8 , A 8 M 1 This yields the remaining four isosceles triangles with lateral faces, whose base side lengths are denoted as . The 8-1 type derivative unit can be obtained by folding. M 1 … M 8 - A The unit height is denoted as .

[0075] The base side length of the 8-1 type derived unit and It can be calculated using the following formula:

[0076]

[0077] Side height The distance between the center of the base and the longer side of the base It can be calculated using the following formula:

[0078]

[0079] The element height of the 8-1 type derived element can be calculated using the above formula. :

[0080]

[0081] Fold the two-dimensional derivative creases along the sides of the quadrilateral or octagon to obtain the 4-1 type I derivative unit, the 4-1 type II derivative unit, and the 8-1 type derivative unit.

[0082] Using polyvinyl alcohol and anhydrous magnesium chloride as the sensing layer materials, this embodiment ultimately obtains a microstructured flexible pressure sensor with 4-1 basic units, 4-1 type-I derived units, 4-1 type-II derived units, and 8-1 type derived units, as shown below. Figure 1As shown. This invention, through the combination of basic units and derived units (such as 4-1 type I, 4-1 type II and 8-1 type), can flexibly design polyhedral microstructures with different contact deformation characteristics to meet the sensor performance requirements of different application scenarios.

[0083] like Figure 6 As shown, pressure loads of 700, 1305, 2317, and 3622 Pa were successively applied to the microstructure flexible pressure sensor. With increasing pressure, the sensor's resistance rate also increased and recovered upon removal of the pressure load, indicating that the sensing unit is highly sensitive to pressure changes.

[0084] like Figure 7 As shown, under a cyclic pressure load of 4255 Pa, the response and recovery of the sensing unit remain stable, indicating that the sensing unit has good pressure response characteristics and repeatability.

[0085] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A microstructure unit derivation design method for a microstructure flexible pressure sensor based on crease evolution, wherein the microstructure flexible pressure sensor based on crease evolution includes a sensitive layer (3), the sensitive layer (3) includes a plate (31) and a series of microstructure units (32), each microstructure unit (32) is connected by the plate (31), the microstructure unit (32) is a series of polyhedral units with a polygonal base, isosceles triangles on the sides and a point on the vertex, the polyhedral unit, when its base is a regular quadrilateral and its isosceles triangles on the sides are equilateral triangles, is defined as a 4-1 type basic unit, where 4 represents the number of vertices of the polygonal base and 1 represents the number of vertices; the polyhedral unit, when its base is a regular quadrilateral and its isosceles triangles on the sides have a height ratio greater than 1, is defined as a 4-1 type basic unit. When defined as a 4-1 type derivative unit, 4 represents the number of vertices of the base polygon, and 1 represents the number of vertices; the polyhedral unit, when its base is a regular quadrilateral and the ratio of the height to the base of its isosceles triangle is less than 1 / 3. When the base polygon is an octagon and its lateral faces are eight isosceles triangles, the polyhedral unit is defined as a 4-1 type II derived unit, where 4 represents the number of vertices of the base polygon and 1 represents the number of vertices. The 4-1 type I, 4-1 type II, and 8-1 type derived units are obtained from the 4-1 type basic unit based on a derivation design method. Its characteristic is... The derived design method includes the following steps: Step 1: Unfold the 4-1 type basic unit along the edge, reducing it from three dimensions to two dimensions, to obtain a two-dimensional crease diagram with a regular quadrilateral in the center and four isosceles triangles around it. Define this as a two-dimensional basic crease. Step 2: Analyze the geometric features of the two-dimensional basic creases. Define the circumcircle of the regular quadrilateral and the circumcircles of the four isosceles triangles as the basic circles. All the surrounding basic circles are tangent to the two adjacent basic circles, and the point of tangency is the vertex of the central regular quadrilateral. Step 3: Based on the similarity evolution strategy, the two-dimensional basic crease evolves to obtain the two-dimensional 4-1 type I derived crease, the two-dimensional 4-1 type II derived crease, and the two-dimensional 8-1 type derived crease; Step 4: Fold the two-dimensional derivative creases along the sides of the quadrilateral or octagon to obtain the 4-1 type I derivative unit, the 4-1 type II derivative unit, and the 8-1 type derivative unit.

2. The derivative design method according to claim 1, characterized in that, The microstructure flexible pressure sensor also includes an upper electrode (1) and a lower electrode (2), the sensitive layer (3) is connected between the upper electrode (1) and the lower electrode (2), and the upper electrode (1) and the lower electrode (2) are wrapped with an encapsulation layer (4).

3. The derivative design method according to claim 2, characterized in that, The upper electrode (1) and lower electrode (2) are made of conductive materials.

4. The derivative design method according to claim 1, characterized in that, The sensitive layer (3) is an ion-conductive hydrogel material made of polyvinyl alcohol and anhydrous magnesium chloride, and a PDMS elastomer doped with conductive materials.

5. The derivative design method according to claim 1, characterized in that, The two-dimensional 4-1 type-1 derived crease described in step 3 is obtained from the two-dimensional basic crease through an amplification and similarity evolution strategy that takes the inner intersection point. The two-dimensional 4-1 type-1 derived crease includes a regular quadrilateral and four isosceles triangles whose base sides coincide with the sides of the regular quadrilateral. The amplification and similarity evolution strategy that takes the inner intersection point is based on the basic circle in the two-dimensional basic crease. Without changing the position of the center of the basic circle, the radius of the basic circle is simultaneously enlarged to obtain a new enlarged derived basic circle. Adjacent derived basic circles intersect each other at two intersection points, one inside and one outside. P in and P out Select four internal intersection points P in The base quadrilateral of the 4-1 type derived polyhedron unit is obtained by connecting them sequentially. A perpendicular bisector is drawn on each side of the base quadrilateral. The far-distance intersection of the perpendicular bisector with the four enlarged derived base circles is taken as the vertex of the lateral isosceles triangle. The four isosceles triangles are obtained by connecting them sequentially.

6. The derivative design method according to claim 1, characterized in that, The two-dimensional 4-1 type II derived crease described in step 3 is obtained from the two-dimensional basic crease through an amplification and similarity evolution strategy using the diplomatic point. The two-dimensional 4-1 type II derived crease includes a regular quadrilateral and four isosceles triangles whose base sides coincide with the sides of the regular quadrilateral. The amplification and similarity evolution strategy using the diplomatic point is based on the basic circle in the two-dimensional basic crease. Without changing the position of the center of the basic circle, the radius of the basic circle is simultaneously enlarged to obtain a new enlarged derived basic circle. Adjacent derived basic circles intersect each other at two intersection points, one inside and one outside. P in and P out Select four diplomatic points P out The base quadrilateral of the 4-1 type II derived polyhedron unit is obtained by connecting them sequentially. A perpendicular bisector is drawn on each side of the base quadrilateral. The far-distance intersection of the perpendicular bisector with the four enlarged derived base circles is taken as the vertex of the isosceles triangle on the side. The four isosceles triangles are obtained by connecting them sequentially.

7. The derivative design method according to claim 1, characterized in that, The two-dimensional 8-1 type derived crease described in step 3 is obtained from the two-dimensional basic crease through a reduction similarity evolution strategy. The two-dimensional 8-1 type derived crease includes an octagon and eight isosceles triangles whose base sides coincide with the sides of the octagon. The reduction similarity evolution strategy is based on the basic circle in the two-dimensional basic crease. Without changing the position of the center of the basic circle, the radius of the basic circle is reduced simultaneously to obtain new, mutually disjoint reduced derived basic circles. Connecting the centers of the reduced derived basic circles yields a regular quadrilateral. The regular quadrilateral intersects the reduced derived basic circles to obtain eight intersection points. Connect the eight intersection points in sequence to obtain an octagon of type 8-1 derived crease. Draw the perpendicular bisectors of the four sides of the octagon that are inside the reduced derived base circle. Take the farthest intersection point of the perpendicular bisector with the four reduced derived base circles as the vertices of the four isosceles triangles on the sides. Connect them in sequence to obtain four isosceles triangles. With the eight vertices of the octagon as the center and the side lengths of the four isosceles triangles obtained above as the radius, draw arcs. The intersection points of adjacent arcs are the vertices of the remaining four isosceles triangles. Connect them in sequence to obtain the remaining four isosceles triangles of the two-dimensional type 8-1 derived crease.

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