CN114752017B

CN114752017B - Rigidity-variable composite material, rigidity-variable system and grabbing equipment

Info

Publication number: CN114752017B
Application number: CN202210430026.4A
Authority: CN
Inventors: 孙一博; 张凯; 渐南南; 吕荣浩; 伊继烜
Original assignee: Beijing Institute of Technology BIT
Current assignee: Beijing Institute of Technology BIT
Priority date: 2022-04-22
Filing date: 2022-04-22
Publication date: 2023-07-18
Anticipated expiration: 2042-04-22
Also published as: CN114752017A

Abstract

The present disclosure provides a stiffness variable composite comprising: a substrate made of a first material; inclusions made of a second material; wherein the inclusions flow through the substrate and are adapted to react with the substrate in a state in which the substrate is under pressure to change the stiffness of at least a portion of the substrate in the pressed position. Under the state that the base material is stressed, the base material made of the first material reacts with the inclusion made of the second material to improve the rigidity of at least one part of the pressed position of the base material, so that the wear resistance of the position can be improved, and the service life of the position contacted with the article can be effectively prolonged. A variable stiffness system and grasping apparatus are also provided.

Description

Rigidity-variable composite material, rigidity-variable system and grabbing equipment

Technical Field

At least one embodiment of the present disclosure relates to a variable stiffness composite, and more particularly to a variable stiffness composite, a variable stiffness system, and a grasping device.

Background

Gripping devices are classified into flexible gripping (made of flexible material at the portion contacting the article) and rigid gripping (made of hard material at the portion contacting the article) depending on the material characteristics of the portion contacting the article. In the flexible grabbing mode, the contact part of grabbing equipment and the object is made of homogeneous materials.

In the practical application process, as the grabbed articles are different, the positions of the grabbed articles, which are worn in the working process, are concentrated in the local areas contacted with the articles, the homogeneous materials cannot form higher rigidity in the local areas with concentrated stress, and therefore once the local areas contacted with the articles are seriously worn, the homogeneous materials need to be replaced integrally, so that the service life of the flexible materials is shorter.

Disclosure of Invention

Aiming at the prior art problems, the invention provides a rigidity-variable composite material, a rigidity-variable system and grabbing equipment, which are used for at least partially solving the technical problems.

One aspect of the present disclosure provides a stiffness-variable composite comprising: a substrate made of a first material; inclusions made of a second material; wherein the inclusions flow through the substrate, and wherein the inclusions are adapted to react with the substrate in a state in which the substrate is under pressure to change the stiffness of at least a portion of the substrate in a pressed position.

In an exemplary embodiment, a flow-directing cavity is formed within the substrate and adapted to direct the inclusions to flow through the substrate.

In an exemplary embodiment, the flow directing cavities are configured as a mesh structure disposed along the length and/or width of the substrate.

In an exemplary embodiment, the flow directing chamber includes: a plurality of warp cavities arranged along the width direction of the base material; a plurality of weft cavities arranged along the length direction of the base material, wherein each weft cavity is communicated with at least one part of warp cavities; the liquid inlet is formed on the warp cavity and/or the weft cavity and is suitable for guiding the inclusion to flow into the flow guiding cavity; and the liquid outlet is formed on the warp cavity and/or the weft cavity and is suitable for guiding the inclusion to flow out of the flow guiding cavity.

In an exemplary embodiment, the first material comprises a dual-network hydrogel made with sodium poly-2-acrylamido-2-methylpropanesulfonate as the first network monomer.

In an exemplary embodiment, the second material comprises an aqueous solution of 2-acrylamido-2-methyl-1-propanesulfonic acid sodium salt and N, N' -methylenebisacrylamide as a crosslinker; wherein the inclusions are adapted to react with the substrate to form a more double network hydrogel in a state where the substrate is under pressure, to increase the rigidity of the substrate at the pressed location.

An aspect of the present disclosure also provides a variable stiffness system, comprising: a substrate layer made of a stiffness-variable composite material; a sensing assembly disposed on a first side of the substrate layer adapted to detect a pressure applied by a second side of the substrate layer facing away from the first side; and the circulating assembly is communicated with the diversion cavity and is in communication connection with the sensing assembly, and is suitable for adjusting at least one of the concentration, the pressure and the flow of the inclusion flowing into the diversion cavity according to the pressure detected by the sensing assembly.

In an exemplary embodiment, the sensing assembly includes a resistive pressure sensor.

In an exemplary embodiment, the circulation assembly includes: the liquid storage unit is suitable for storing the inclusions, and a liquid inlet end and a liquid outlet end of the liquid storage unit are respectively communicated with the flow guide cavity; the liquid pump unit is communicated with the liquid storage unit and is suitable for inputting or extracting the inclusion into or out of the diversion cavity; and the control unit is in communication connection with the induction component and the liquid storage unit and/or the liquid pump unit, is suitable for collecting signals output by the induction component, and controls the liquid storage unit and/or the liquid pump unit according to the signals, and is used for inputting the impurities into the diversion cavity.

An aspect of the present disclosure also provides a grasping apparatus including: a plurality of finger portions; and a substrate layer formed of the variable stiffness composite material and disposed on at least a portion of a surface of the finger portion for contacting an article.

The embodiment of the invention discloses a rigidity-variable composite material, a rigidity-variable system and grabbing equipment. The substrate and the inclusion flowing through the substrate form a rigidity-variable composite material, and under the state that the substrate is stressed, the substrate made of the first material reacts with the inclusion made of the second material to improve the rigidity of at least one part of the stressed position of the substrate, so that the wear resistance of the position is improved, and the service life of the position contacted with an article can be effectively prolonged.

Drawings

FIG. 1 is a schematic illustration of a variable stiffness composite according to an exemplary embodiment of the present disclosure;

FIG. 2 is a top view of a flow directing cavity portion of the variable stiffness composite in the illustrative embodiment shown in FIG. 1;

FIG. 3 is a reaction diagram of the reaction of a substrate with inclusions in the exemplary embodiment shown in FIG. 1; 3A is a reaction process diagram of the 2-acrylamide-2-methylpropanesulfonic acid sodium polymer chain with broken covalent bond to form mechanical free radical; 3B is a reaction process diagram of the sodium salt of 2-acrylamido-2-methyl-1-propanesulfonic acid to form new free radicals; 3C is a reaction process diagram of two new free radicals to generate free radical polymerization to form a second polymer chain of 2-acrylamide-2-methylpropanesulfonic acid sodium polymer; 3D is a reaction process diagram of forming covalent bonds between N, N' -methylene bisacrylamide serving as a cross-linking agent and a second polymer chain of sodium 2-acrylamide-2-methylpropanesulfonate;

FIG. 4 is a module connection diagram of a variable stiffness system according to an exemplary embodiment of the present disclosure; and

fig. 5 is a bottom view of a gripping apparatus according to an exemplary embodiment of the present disclosure.

Reference numerals

1. A variable stiffness system;

11. a substrate layer;

111. a substrate;

112. inclusion;

113. a diversion cavity;

12. an induction assembly;

13. a circulation assembly;

2. a base; and

21. a finger part.

Detailed Description

The present invention will be further described in detail below with reference to specific embodiments and with reference to the accompanying drawings, in order to make the objects, technical solutions and advantages of the present invention more apparent.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The terms "comprises," "comprising," and/or the like, as used herein, specify the presence of stated features, steps, operations, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, or components.

All terms, including technical and scientific terms, used herein have the meaning commonly understood by one of ordinary skill in the art unless otherwise defined. It should be noted that the terms used herein should be construed to have meanings consistent with the context of the present specification and should not be construed in an idealized or overly formal manner.

Where expressions like at least one of "A, B and C, etc. are used, the expression" system having at least one of A, B and C "shall be construed, for example, in general, in accordance with the meaning of the expression as commonly understood by those skilled in the art, and shall include, but not be limited to, systems having a alone, B alone, C alone, a and B together, a and C together, B and C together, and/or A, B, C together, etc. Where a formulation similar to at least one of "A, B or C, etc." is used, such as "a system having at least one of A, B or C" shall be interpreted in the sense one having ordinary skill in the art would understand the formulation generally, for example, including but not limited to systems having a alone, B alone, C alone, a and B together, a and C together, B and C together, and/or A, B, C together, etc.

FIG. 1 is a schematic illustration of a variable stiffness composite according to one exemplary embodiment of the present disclosure. FIG. 2 is a top view of a flow directing cavity portion of the variable stiffness composite in the illustrative embodiment shown in FIG. 1. FIG. 3 is a reaction diagram of the reaction of a substrate with inclusions in the exemplary embodiment shown in FIG. 1.

The present disclosure provides a variable stiffness composite, as shown in fig. 1 and 2, comprising a substrate 111 of a first material and inclusions 112 of a second material. The inclusions 112 flow through the substrate 111, and in a state where the substrate 111 is subjected to pressure, the inclusions 112 are adapted to react with the substrate 111 to change the rigidity of at least a portion of the pressed position of the substrate 111. In such embodiments, the variable stiffness composite material may be used out of solution (e.g., by immersing the substrate 111 of the first material in a solution made of the second material) because the inclusions 112 flow through the substrate 111.

In an exemplary embodiment, the variable stiffness material may be provided on the surface of other mechanisms. For example, at the surface of the gripping means that is in contact with the article.

In detail, in the above-described usage scenario, the inclusions 112 circulate in the internal space defined by the base material 111, and thus, the inclusions 112 are configured to maintain the function of the rigidity-variable material with the base material 111 in a relatively independent environment even when the external environment of the usage scenario (including, but not limited to, temperature and/or humidity) is changed.

In an exemplary embodiment, the first material includes, but is not limited to, at least one of a silicone gel, a rubber, or other material.

In an exemplary embodiment, the second material includes, but is not limited to, a liquid.

In detail, the second material flows within the substrate made of the first material. It should be understood that embodiments of the present disclosure are not limited thereto.

For example, the second material also includes a gas.

In accordance with an embodiment of the present disclosure, as shown in fig. 1 and 2, a flow directing cavity 113 is formed in the substrate 111 that is adapted to direct inclusions to flow through the substrate.

According to an embodiment of the present disclosure, as shown in fig. 2, the flow directing cavities 113 are configured as a mesh structure, disposed along the length and/or width of the substrate.

In an exemplary embodiment, the flow directing chamber 113 is configured as a mesh structure.

In detail, the mesh structure preferably covers a large area of the substrate 111.

In another exemplary embodiment, the flow guiding chamber 113 is configured as a plurality of mesh structures, each of which is stacked in the thickness direction of the base material 111.

In detail, the plurality of mesh structures are connected to each other or independent. It should be understood that embodiments of the present disclosure are not limited thereto.

For example, the flow directing cavities 113 are configured in a spiral configuration, either from the outside of the substrate 111 inward or from the inside of the substrate 111 outward.

For another example, the flow guiding chamber 113 is configured in an S-shaped structure, formed by an S-shaped arrangement on one side of the substrate 111. Preferably, the diffusion speed and the diffusion uniformity of the inclusions in the guide cavity 113 are facilitated.

According to an embodiment of the present disclosure, as shown in fig. 2, the flow guiding chamber 113 includes a plurality of warp chambers and a plurality of weft chambers. The warp cavities are arranged in the width direction of the substrate layer 11. The weft cavities are arranged along the length direction of the base material layer 11 and are communicated with at least a part of the warp cavities. The warp cavity and/or the weft cavity are/is provided with a liquid inlet and a liquid outlet, the liquid inlet is communicated with the liquid outlet end of the circulation assembly 13, and the liquid outlet is communicated with the liquid inlet end of the circulation assembly 13.

In one illustrative embodiment, the substrate 111 is configured as a rectangle.

In detail, a plurality of warp cavities are uniformly provided at intervals along the length direction of the base material 111.

Further, a plurality of weft cavities are provided at uniform intervals along the width direction of the base material 111, and each weft cavity is communicated with each warp cavity in sequence. The middle part in one weft chamber is equipped with the inlet, and the middle part in another weft chamber is equipped with the liquid outlet. It should be understood that embodiments of the present disclosure are not limited thereto.

In an exemplary embodiment, the mesh structure of the flow directing chamber 113 includes, but is not limited to, being formed by three-dimensional printing.

In detail, a mesh structure is printed with a polyvinyl alcohol (PVA) material as a sacrificial material.

Further, after the net structure is placed in a mold, the double-network hydrogel is formed by casting.

Further, after the sacrificial material is dissolved, a diversion cavity 113 is formed.

According to embodiments of the present disclosure, the first material includes, but is not limited to, a dual-network hydrogel having sodium poly-2-acrylamido-2-methylpropanesulfonate as the first network monomer.

According to embodiments of the present disclosure, the second material includes, but is not limited to, an aqueous solution of 2-acrylamido-2-methyl-1-propanesulfonic acid sodium salt and N, N' -methylenebisacrylamide as a crosslinking agent.

In an exemplary embodiment, the dual-network hydrogel is prepared by a method comprising mixing a first network monomer, a cross-linking agent, an initiator, and water to obtain a first mixture; placing the first mixed solution into a mould, and crosslinking under the ultraviolet irradiation condition to prepare single-network hydrogel; mixing a cross-linking agent, an initiator and water to prepare a second mixed solution, and soaking the single-network hydrogel in the second mixed solution; and taking out the soaked single-network hydrogel and crosslinking under the ultraviolet irradiation condition to obtain the double-network gel.

In an exemplary embodiment, mixing the first network monomer, the cross-linking agent, the initiator, and water to form a first mixture includes taking 2.5 grams of the first network monomer; 0.0653 g of cross-linking agent is taken; taking 0.02 g of an initiator; the first network monomer, the cross-linking agent and the initiator are dissolved in 10 g of water and are fully stirred until the first network monomer, the cross-linking agent and the initiator are completely dissolved.

In detail, the first network monomer includes, but is not limited to, sodium poly-2-acrylamido-2-methylpropanesulfonate, the crosslinking agent includes, but is not limited to, N' -methylenebisacrylamide, and the initiator includes, but is not limited to, alpha-ketoglutarate.

In an exemplary embodiment, placing the first mixed solution in a mold and crosslinking under ultraviolet light conditions to produce a single network hydrogel includes injecting the first mixed solution into the mold; covering the glass sheet subjected to surface hydrophobic treatment at the opening position of the mould; the mold was placed in an ultraviolet cross-linker and reacted for 1.5 hours until the first mixed solution solidified to form a single network hydrogel.

In one illustrative embodiment, mixing the cross-linking agent, the initiator, and the water to form a second mixed solution, and immersing the single-network hydrogel in the second mixed solution comprises immersing the single-network hydrogel in the second mixed solution for 24 hours.

In detail, the molar mass of the crosslinking agent in the second mixed liquor comprises 0.08 g/mol, and the molar mass of the initiator in the second mixed liquor comprises 0.08 g/mol.

Further, the crosslinking agent includes, but is not limited to, N' -methylenebisacrylamide, and the initiator includes, but is not limited to, alpha-ketoglutarate.

In an exemplary embodiment, taking out the soaked single-network hydrogel and crosslinking under ultraviolet irradiation to prepare a double-network gel, wherein the single-network hydrogel is clamped between two acrylic plates; and (3) placing the acrylic plate into an ultraviolet crosslinking instrument, and reacting for 1.5 hours until the single-network gel is solidified to form the double-network hydrogel.

FIG. 3 is a reaction diagram of the substrate layer reacting with inclusions in the exemplary embodiment shown in FIG. 1; 3A is a reaction process diagram of the 2-acrylamide-2-methylpropanesulfonic acid sodium polymer chain with broken covalent bond to form mechanical free radical; 3B is a reaction process diagram of the sodium salt of 2-acrylamido-2-methyl-1-propanesulfonic acid to form new free radicals; 3C is a reaction process diagram of two new free radicals to generate free radical polymerization to form a second polymer chain of 2-acrylamide-2-methylpropanesulfonic acid sodium polymer; 3D is a reaction process diagram of N, N' -methylene bisacrylamide serving as a cross-linking agent and forming a covalent bond with a second polymer chain of sodium 2-acrylamide-2-methylpropanesulfonate.

In the embodiment in which the dual-network hydrogel prepared by the preparation method is used as the substrate 111, as shown in fig. 3, when the substrate 111 is deformed under pressure, covalent bonds of the polymer chains of the first sodium poly-2-acrylamido-2-methylpropanesulfonate (PNaAMPS) are broken, and a large amount of mechanical free radicals (e.g., 3A) are generated. The sodium salt of 2-acrylamido-2-methyl-1-propanesulfonic acid (NaAMPS) in the mechanical free radical initiating inclusions forms new radicals (e.g., 3B). Two new radicals undergo free radical polymerization to form a second polymer chain (e.g., 3C) of sodium 2-acrylamido-2-methylpropanesulfonate (PNaAMPS) polymer. N, N' -Methylenebisacrylamide (MBAA) is used as a cross-linking agent to form a covalent bond with a second polymer chain of sodium 2-acrylamido-2-methylpropanesulfonate (PNaAMPS) to generate a hydrogel with a three-dimensional network structure, so that the wear resistance (such as 3D) of the substrate 111 is effectively improved.

In one exemplary embodiment of the present invention,

the flow rate of the inclusion 112 can be adjusted, and the local concentration of the reactant can be adjusted, so that the reaction speed of the inclusion 112 and the base material 111 can be adjusted, and the rigidity change rate of the composite material can be adjusted.

For another example, the reaction rate of the inclusions 112 with the base material 111 may be adjusted by directly adjusting the concentration of the inclusions 112 (the higher the reaction rate of the inclusions with the base material in a state where the concentration of the inclusions is higher (before the entire reaction of the base material in contact with the inclusions and/or before the concentration of the inclusions exceeds the concentration suitable for reaction with the base material)). Still further, the stiffness change of the composite material may be suspended by reducing the inclusion concentration to a certain level.

Fig. 4 is a module connection diagram of a variable stiffness system according to one exemplary embodiment of the present disclosure.

The present disclosure also provides a variable stiffness system, as shown in fig. 4, comprising a substrate layer 11 made of a variable stiffness composite, a sensing assembly 12, and a circulation assembly 13. The sensing element 12 is disposed on a first side of the substrate layer 11 and is adapted to detect a pressure applied by a second side of the substrate layer 11 facing away from the first side. The circulation assembly 13 is communicated with the diversion cavity 113 and is in communication connection with the sensing assembly 12, and is suitable for adjusting at least one of the concentration, the pressure and the flow of the impurities flowing into the diversion cavity 113 according to the pressure detected by the sensing assembly 12. The inclusions are adapted to react with the base material layer 11 in a state where the base material layer 11 is subjected to pressure, so as to increase the rigidity of at least a part of the pressed position of the base material layer 11.

In an exemplary embodiment, the substrate layer 11 is configured in a rectangular shape.

In accordance with an embodiment of the present disclosure, as shown in FIG. 4, sensing assembly 12 includes a resistive pressure sensor. It should be understood that embodiments of the present disclosure are not limited thereto.

For example, sensing assembly 12 includes, but is not limited to, a voltage pressure sensor, a film pressure sensor, or other device suitable for converting a pressure signal into an electrical or digital signal.

According to an embodiment of the present disclosure, as shown in fig. 4, the circulation assembly 13 includes a liquid storage unit, a liquid pump unit, and a control unit. The liquid storage unit is suitable for storing impurities, and the liquid inlet end and the liquid outlet end of the liquid storage unit are respectively communicated with the flow guide cavity 113. The liquid pump unit is communicated with the liquid storage unit and is suitable for inputting or outputting the impurities into or out of the diversion cavity 113. The control unit is in communication connection with the sensing assembly 12 and the liquid storage unit and/or the liquid pump unit, and is suitable for collecting signals output by the sensing assembly 12, and controlling the liquid storage unit and/or the liquid pump unit according to the signals, so as to output the impurities to the diversion cavity 113.

In an exemplary embodiment, a liquid storage cavity is defined in the liquid storage unit, single-concentration inclusions are stored in the liquid storage cavity, and the liquid storage cavity is communicated with the liquid pump unit.

In another illustrative embodiment, a plurality of fluid storage chambers are defined within the fluid storage unit.

In detail, the concentration of inclusions in at least two liquid storage chambers is different.

Further, each liquid storage cavity is communicated with one liquid pump unit, and is suitable for inputting impurities with different concentrations into the diversion cavity 113.

Furthermore, any two liquid storage cavities for storing impurities with different concentrations are mutually communicated, and a valve body is arranged on a corresponding pipeline, so that the impurities with the first concentration, the impurities with the second concentration and the impurities with the third concentration after mixing can be selected to be communicated through the communication or the closing of the valve body.

In yet another exemplary embodiment, a mixing chamber and a plurality of liquid storage chambers are defined in the liquid storage unit, a flow meter (and other devices suitable for measuring at least one of the volume, the mass and the concentration of the liquid flowing out of the liquid storage chambers) is arranged between each liquid storage chamber and each liquid storage chamber, and one type of solution is stored in each liquid storage chamber, so that different solutions can be mixed to form inclusions with different concentrations under different conduction time, flow rate and flow velocity conditions.

In one illustrative embodiment, the liquid pump unit includes, but is not limited to, a miniature liquid pump (miniature liquid pump) and associated tubing.

In detail, the tubing includes, but is not limited to, polyurethane (PU) material.

In an exemplary embodiment, the control unit includes, but is not limited to, a single-chip microcomputer.

In detail, the single-chip microcomputer is adapted to collect the electrical signal output by the sensing component 12, and drive the liquid storage unit (such as switching on different liquid storage cavities) and/or the liquid pump unit (such as adjusting the flow rate, the flow velocity, etc. of the liquid pump) according to the electrical signal. Fig. 5 is a bottom view of a gripping apparatus according to an exemplary embodiment of the present disclosure.

The present disclosure also provides a gripping apparatus, as shown in fig. 5, comprising a plurality of finger portions 21 and a substrate layer 11 formed of a composite material provided on at least a portion of the surface of the finger portions 21 for contacting an article.

In an exemplary embodiment, as shown in fig. 5, the gripping device includes a base 2, and the base 2 is provided with a plurality of protrusions at uniform intervals in the circumferential direction, and each protrusion is provided with a finger portion 21, which is perpendicular to the base 2.

In detail, each finger 21 is further provided with at least one sensing assembly 12 of the variable stiffness system 1.

Further, the sensing element 12 is disposed on the opposite surface of the finger portion 21, and the substrate layer 11 is disposed on the opposite surface of the sensing element 12 and the finger portion 21.

Still further, at least one circulation assembly 13 of the variable stiffness system 1 is provided on each finger 21.

Those skilled in the art will appreciate that the features recited in the various embodiments of the disclosure and/or in the claims may be provided in a variety of combinations and/or combinations, even if such combinations or combinations are not explicitly recited in the disclosure. In particular, the features recited in the various embodiments of the present disclosure and/or the claims may be variously combined and/or combined without departing from the spirit and teachings of the present disclosure. All such combinations and/or combinations fall within the scope of the present disclosure.

The embodiments of the present disclosure are described above. However, these examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Although the embodiments are described above separately, this does not mean that the measures in the embodiments cannot be used advantageously in combination. The scope of the disclosure is defined by the appended claims and equivalents thereof. Various alternatives and modifications can be made by those skilled in the art without departing from the scope of the disclosure, and such alternatives and modifications are intended to fall within the scope of the disclosure.

Claims

1. A variable stiffness composite comprising:

a substrate (111) made of a first material; and

inclusions (112) made of a second material;

wherein the inclusions (112) flow through the substrate (111), the inclusions (112) being adapted to react with the substrate (111) in a state in which the substrate (111) is subjected to pressure, for changing the stiffness of at least a part of the pressed position of the substrate (111);

-forming a flow-guiding cavity (113) in said substrate (111), adapted to guide said inclusions (112) through said substrate (111);

the first material comprises double-network hydrogel prepared by taking poly-2-acrylamide-2-methylpropanesulfonic acid sodium salt as a first network monomer, and the second material comprises aqueous solution taking 2-acrylamide-2-methyl-1-propanesulfonic acid sodium salt and N, N' -methylenebisacrylamide as a cross-linking agent;

the inclusions are adapted to react with the substrate in a state where the substrate is under pressure to form more of a double network hydrogel to increase the rigidity of the substrate in the pressed position.

2. The composite material according to claim 1, wherein the flow guiding cavities (113) are configured as a mesh structure, arranged along the length and/or width direction of the substrate.

3. The composite of claim 2, wherein the flow directing chamber comprises:

a plurality of warp cavities arranged along the width direction of the base material;

a plurality of weft cavities arranged along the length direction of the base material, wherein each weft cavity is communicated with at least one part of warp cavities;

the liquid inlet is formed on the warp cavity and/or the weft cavity and is suitable for guiding the inclusion to flow into the flow guiding cavity; and

the liquid outlet is formed on the warp cavity and/or the weft cavity and is suitable for guiding the inclusion to flow out of the flow guiding cavity.

4. A variable stiffness system, comprising: a substrate layer (11) made of a variable stiffness composite according to any of claims 1 to 3;

a sensing element (12) arranged on a first side of the substrate layer (11) and adapted to detect a pressure applied by a second side of the substrate layer (11) facing away from the first side; and

the circulating assembly (13) is communicated with the diversion cavity (113) and is in communication connection with the sensing assembly (12), and is suitable for adjusting at least one of the concentration, the pressure and the flow of the impurities flowing into the diversion cavity (113) according to the pressure detected by the sensing assembly (12).

5. The system of claim 4, wherein the sensing assembly (12) comprises a resistive pressure sensor.

6. The system according to claim 4, characterized in that the circulation assembly (13) comprises:

the liquid storage unit is suitable for storing the inclusions, and a liquid inlet end and a liquid outlet end of the liquid storage unit are respectively communicated with the flow guide cavity (113);

a liquid pump unit, which is communicated with the liquid storage unit and is suitable for inputting or extracting the inclusion into or out of the diversion cavity (113); and

the control unit is in communication connection with the induction component (12) and the liquid storage unit and/or the liquid pump unit, and is suitable for collecting signals output by the induction component (12), controlling the liquid storage unit and/or the liquid pump unit according to the signals, and inputting the inclusion into the diversion cavity (113).

7. A gripping apparatus, comprising:

a plurality of finger sections (21); and

a substrate layer formed of a variable stiffness composite material according to any one of claims 1 to 3, provided on at least a portion of the surface of the finger portion (21) for contact with an article.