Mine wind speed and non-contact sensing bionic flexible sensor and preparation method thereof

Abstract

The present application relates to the technical field of mine sensor, in particular to a mine wind speed and non-contact sensing bionic flexible sensor and a preparation method thereof, which mainly solves the technical problems of existing wind speed measuring sensor, such as serious mechanical wear, high starting wind speed, limited measuring accuracy, and low integration degree of independent layout and integration with proximity detection sensor. The sensor comprises an upper electrode layer, a dielectric layer and a lower electrode layer fixedly connected in sequence from top to bottom. The upper electrode layer comprises a first substrate and flexible cilia arranged on the top surface of the first substrate. The top surface of the first substrate and the flexible cilia are collectively covered with a first conductive film. The upper electrode layer serves as a resistance test layer to measure wind speed and as a voltage test layer to realize non-contact proximity detection. The lower electrode layer comprises a second substrate and a second conductive film, which serves as an excitation electrode layer to generate an excitation electric field. The present application also provides a preparation method of the sensor. The present application integrates dual functions in a single sensor, has high integration degree, no mechanical wear and low starting wind speed.

Description

Technical Field

[0001] This invention relates to the field of mining sensor technology, and in particular to a biomimetic flexible sensor for mining wind speed and non-contact sensing, and its preparation method. Background Technology

[0002] Mine ventilation systems play a crucial supporting role in coal mine safety production. Their core task is to continuously improve underground air conditions, effectively remove harmful gases such as methane and carbon monoxide, and thus maintain a stable and safe underground environment. Ensuring the efficient and stable operation of the ventilation system is of irreplaceable importance in preventing major safety accidents such as gas explosions and fires. In ventilation monitoring, wind speed measurement is of paramount importance.

[0003] Existing wind speed sensors mostly employ mechanical anemometers, such as cup anemometers and tail fin anemometers. While these offer advantages like simple structure and low cost, their mechanical components are prone to wear, and they suffer from drawbacks such as high starting wind speed requirements and limited measurement accuracy. Furthermore, in mining environments, proximity sensors are needed near mobile equipment such as continuous mining machines, shuttle cars, and loader conveyors to enable non-contact proximity monitoring of personnel. However, existing wind speed sensors and proximity sensors have limited functionality and must be deployed as two separate components, resulting in low integration and high structural costs.

[0004] Therefore, there is an urgent need for a dual-function sensor that can function as both a wind speed sensor and a proximity detection sensor, and that has no mechanical wear, low starting wind speed, and high measurement accuracy. Summary of the Invention

[0005] To overcome the technical shortcomings of existing wind speed measuring sensors, such as severe mechanical wear, high starting wind speed, limited measurement accuracy, and the need for independent deployment and low integration with proximity detection sensors, this invention proposes a biomimetic flexible wind speed and non-contact sensing sensor for mining and its fabrication method.

[0006] The present invention provides a biomimetic flexible sensor for mining wind speed and non-contact sensing, comprising:

[0007] The upper electrode layer includes a first substrate and flexible fibers disposed on the top surface of the first substrate. The top surface of the first substrate and the flexible fibers are jointly covered with a first conductive film. The upper electrode layer is used as a resistance test layer to measure wind speed and as a voltage test layer to realize non-contact proximity detection.

[0008] A dielectric layer, which is fixedly connected to the underside of the upper electrode layer;

[0009] A lower electrode layer is fixedly connected below the dielectric layer. The lower electrode layer includes a second substrate and a second conductive film. The second conductive film covers the top or bottom surface of the second substrate. The lower electrode layer is used as an excitation electrode layer to generate an excitation electric field.

[0010] Furthermore, the first substrate is made of a flexible elastomer material.

[0011] Furthermore, the first substrate and the flexible fibers are integrally molded.

[0012] Furthermore, the flexible cilia are provided in at least two levels, and the length and / or diameter of the flexible cilia in different levels are different.

[0013] Furthermore, the flexible fibers are provided in two levels, with multiple rows of flexible fibers in each level. The two levels of flexible fibers are arranged alternately, and the flexible fibers in adjacent rows are staggered.

[0014] Furthermore, both the first substrate and the second substrate are fixedly connected to the dielectric layer by adhesive bonding.

[0015] The method for fabricating a mine wind speed and non-contact sensing biomimetic flexible sensor provided by this invention includes the following steps:

[0016] Preparation of the upper electrode layer: First, a mold for integrally molding the first substrate and flexible fibers is prepared, and a molding liquid is prepared; then, the molding liquid is injected into the mold and the air bubbles are removed, followed by curing and molding, and then the cured colloid is taken out from the mold. Finally, a first conductive film is processed on the side of the cured colloid with flexible fibers to obtain the upper electrode layer.

[0017] Fabrication of dielectric layer;

[0018] Fabrication of the lower electrode layer: First, a planar thin film is prepared as the second substrate, and then a second conductive film is processed on one side surface of the second substrate to obtain the lower electrode layer;

[0019] Assembly: The upper electrode layer, dielectric layer and lower electrode layer are bonded and fixed in sequence.

[0020] Furthermore, the molding liquid is a polydimethylsiloxane mixture, and the ratio of the matrix to the curing agent in the polydimethylsiloxane mixture is 20:1 or 30:1.

[0021] Alternatively, the molding liquid is a silicone rubber mixture, and the ratio of the matrix to the curing agent in the silicone rubber mixture is 1:1.

[0022] Furthermore, the dielectric layer is prepared using insulating silicone.

[0023] Alternatively, the dielectric layer may be prepared using an ionic dielectric material, which is a mixture of an ionic liquid and a polymer framework.

[0024] Furthermore, both the first conductive film and the second conductive film are processed by ion sputtering or spraying a conductive mixture.

[0025] The technical solution provided by this invention has the following advantages compared with the prior art.

[0026] The biomimetic flexible sensor for mine wind speed and non-contact sensing provided by this invention utilizes flexible fibers placed on the top surface of the first substrate of the upper electrode layer. Both the top surface of the first substrate and the flexible fibers jointly cover the first conductive film, allowing the upper electrode layer to simultaneously serve as a resistance testing layer and a voltage testing layer. This achieves both wind speed measurement and non-contact proximity detection functions within a single sensor. Compared to existing solutions where wind speed and proximity sensors are deployed separately, this design offers higher integration and lower structural costs. The flexible fibers deflect under airflow, causing a change in the resistance of the first conductive film. This eliminates the need for mechanical rotating parts, resulting in no mechanical wear, lower starting wind speed, and higher measurement accuracy. The lower electrode layer acts as the excitation electrode layer, generating an excitation electric field. Non-contact proximity detection is achieved through capacitive voltage division, eliminating the need for infrared or ultrasonic transceivers. This design is simple in structure and highly reliable.

[0027] The method for preparing a biomimetic flexible sensor for mining wind speed and non-contact sensing provided by the present invention integrates the first substrate and flexible fibers into one piece by preparing a mold, avoiding the complex process of separate manufacturing and reassembly, and achieving better structural consistency; a first conductive film is processed on the side of the cured colloid with flexible fibers, so that the conductive film directly adheres to the surface of the fibers, resulting in better film quality. Attached Figure Description

[0028] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This diagram illustrates the structure of the biomimetic flexible sensor in an embodiment of the present invention.

[0031] Figure 2 This is a front view of the upper electrode layer in an embodiment of the present invention;

[0032] Figure 3This is a top view of the upper electrode layer in an embodiment of the present invention;

[0033] Figure 4 express Figure 3 A schematic diagram showing the effect of airflow from different directions on region A in the middle;

[0034] Figure 5 This diagram shows the stress of the upper electrode layer under low flow rate in an embodiment of the present invention.

[0035] Figure 6 This diagram shows the stress of the upper electrode layer under high flow rate in an embodiment of the present invention.

[0036] Figure 7 This diagram illustrates the principle of non-contact proximity detection using a biomimetic flexible sensor in an embodiment of the present invention.

[0037] In the picture:

[0038] 100, Upper electrode layer; 110, First substrate; 120, Flexible cilia; 130, First conductive film; 200, Dielectric layer; 300, Lower electrode layer; 310, Second substrate; 320, Second conductive film; 400, System grounding terminal; 500, Earth; 600, External object. Detailed Implementation

[0039] To better understand the above-mentioned objectives, features, and advantages of the present invention, the solutions of the present invention will be further described below. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

[0040] Many specific details are set forth in the following description in order to provide a full understanding of the invention, but the invention may also be practiced in other ways different from those described herein; obviously, the embodiments in the specification are only some embodiments of the invention, and not all embodiments.

[0041] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0042] Reference Figure 1 This embodiment provides a biomimetic flexible sensor for mining wind speed and non-contact sensing, including an upper electrode layer 100, a dielectric layer 200 and a lower electrode layer 300.

[0043] Among them, reference Figure 2 The upper electrode layer 100 includes a first substrate 110 and flexible fibers 120 disposed on the top surface of the first substrate 110. The top surface of the first substrate 110 and the flexible fibers 120 are jointly covered with a first conductive film 130. The upper electrode layer 100 is used as a resistance test layer to measure wind speed and as a voltage test layer to realize non-contact proximity detection.

[0044] Specifically, in this embodiment, the first substrate 110 is made of a flexible elastomer material. When the flexible cilia 120 deflects, the first substrate 110 made of the flexible elastomer material will also deform slightly, avoiding stress concentration at the root of the flexible cilia 120, thereby preventing the flexible cilia 120 from breaking and falling off.

[0045] More specifically, the type of flexible elastomer material is not limited, such as polydimethylsiloxane (PDMS), silicone rubber, etc.

[0046] Specifically, the thickness of the first substrate 110 is not limited, but is preferably 200 μm to 500 μm.

[0047] Specifically, in this embodiment, the first substrate 110 and the flexible fibers 120 are integrally formed. During operation, a mold can be made first, with the mold designed to be the reverse structure of the overall structure of the first substrate 110 and the flexible fibers 120. Then, the components are integrally cast using this mold. Integral molding avoids the creation of weak connection areas, makes operation more convenient, and better ensures the relative positional accuracy of the flexible fibers 120 and the first substrate 110.

[0048] As an improved structure of the flexible cilia 120, the flexible cilia 120 has at least two levels, and the lengths and / or diameters of the flexible cilia 120 in different levels are different. On the one hand, the flexible cilia 120 in different levels are sensitive to different wind speed ranges. At low wind speeds, the longer flexible cilia 120 responds first, and at high wind speeds, the shorter flexible cilia 120 can also respond. The graded combination can cover a wider wind speed range. On the other hand, at the same wind speed, the flexible cilia 120 in different levels produce different deflections, which is equivalent to multi-range deformation measurement, resulting in higher signal resolution.

[0049] Specifically, refer to Figures 2 to 4 In this embodiment, the flexible fibers 120 are provided in two levels, with multiple rows of flexible fibers 120 in each level. The two levels of flexible fibers 120 are arranged alternately, and adjacent rows of flexible fibers 120 are staggered. The size of the two levels of flexible fibers 120 is not limited, but preferably, the diameter and length of one level of flexible fibers 120 are designed to be relatively large. For example, the diameter of one level of flexible fibers 120 is 50μm and the length is 200μm, while the diameter of the other level of flexible fibers 120 is 100μm and the length is 400μm. The alternating arrangement ensures that each level of flexible fibers 120 can fully contact the airflow; the staggered arrangement avoids the formation of straight airflow channels between flexible fibers 120 in the same row, which could lead to airflow misses, thus enabling the flexible fibers 120 to fully cover the airflow.

[0050] Specifically, the forming method of the first conductive film 130 is not limited. For example, the first conductive film 130 can be formed by ion sputtering or spraying a conductive mixture.

[0051] The dielectric layer 200 is fixedly connected below the upper electrode layer 100.

[0052] Specifically, in this embodiment, the dielectric layer 200 is fixedly connected to the underside of the upper electrode layer 100 by adhesive bonding. The specific bonding method is not limited, for example, a PDMS mixture can be spin-coated onto the bottom surface of the first substrate 110 and / or the top surface of the dielectric layer 200 to achieve bonding between the dielectric layer 200 and the upper electrode layer 100.

[0053] Specifically, the material of dielectric layer 200 is not limited. For example, it can be insulating silicone such as PDMS, or it can be an ionic dielectric material composed of an ionic liquid and a polymer backbone. The ionic liquid is preferably 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, and the polymer backbone is preferably polyvinylidene fluoride-hexafluoropropylene copolymer.

[0054] The lower electrode layer 300 is fixedly connected below the dielectric layer 200. The lower electrode layer 300 includes a second substrate 310 and a second conductive film 320. The second conductive film 320 covers the top or bottom surface of the second substrate 310. The lower electrode layer 300 is used as an excitation electrode layer to generate an excitation electric field.

[0055] Specifically, the material of the second substrate 310 is not limited. For example, in this embodiment, a planar thin film made of PDMS is used as the second substrate 310.

[0056] Specifically, in this embodiment, the second substrate 310 is fixedly connected to the underside of the dielectric layer 200 by adhesive bonding. The specific bonding method is not limited, for example, a PDMS mixture can be spin-coated onto the bottom surface of the dielectric layer 200 and / or the top surface of the second substrate 310 to achieve bonding between the dielectric layer 200 and the lower electrode layer 300.

[0057] Specifically, the forming method of the second conductive film 320 is not limited. For example, the second conductive film 320 can be formed by ion sputtering or spraying a conductive mixture.

[0058] The working principle of the mine wind speed and non-contact sensing biomimetic flexible sensor provided by this invention is as follows:

[0059] When measuring wind speed, the upper electrode layer 100 serves as a resistance testing layer, and leads are used to connect the first conductive film 130 to resistance testing instruments such as multimeters and resistance meters. When airflow passes, the flexible cilia 120 deflect under the stimulation of external wind speed, causing deformation of the first conductive film 130, which in turn leads to a change in the resistance of the first conductive film 130. The resistance testing instrument collects this change in resistance to obtain the corresponding wind speed information. (Comparison) Figure 5 and Figure 6 It can be concluded that the higher the flow velocity, the greater the deflection of the flexible cilia 120, and the greater the stress. Figure 5 Small flow rates and Figure 6 The stress difference of flexible fibers 120 under high flow velocity is obvious, indicating that the resistance change is significantly different under different wind velocities, and the resolution is high.

[0060] In the non-contact proximity detection, the upper electrode layer 100 serves as a voltage testing layer and is connected to the analog-to-digital converter (ADC) of a voltage detection instrument such as a multimeter or microcontroller via leads. The lower electrode layer 300 serves as an excitation electrode layer and is connected to a signal source via leads. The signal source applies a high-frequency square wave or sine wave signal of 100kHz to 1000kHz to the lower electrode layer 300, with a voltage amplitude of 3V to 5V. The lower electrode layer 300 generates an electric field around the sensor. When an external object 600 approaches, it disrupts this electric field, causing a change in the voltage of the upper electrode layer 100. The voltage detection instrument collects this voltage change to obtain the proximity distance of the external object 600.

[0061] Reference Figure 7 The capacitor is defined by the upper electrode layer 100, the lower electrode layer 300, and the intermediate dielectric layer 200. An external object 600 and the upper electrode layer 100 form a capacitor. A capacitor is formed between the upper electrode layer 100 and the system ground terminal 400. A capacitor is formed between the lower electrode layer 300 and the system ground terminal 400. An external object 600 and the ground 500 form a capacitor. A capacitor is formed between the ground 500 and the system grounding terminal 400. Based on the principle of capacitive voltage division, the induced voltage of the upper electrode layer 100... and the excitation voltage of the lower electrode layer 300 The relationship between them is:

[0062] ;

[0063] Since the system grounding terminal 400 is connected to the earth 500, the above formula can be simplified to:

[0064] ;

[0065] because Therefore, the above formula can be simplified to:

[0066] ;

[0067] When an external object 600 approaches, a capacitor is formed between the external object 600 and the upper electrode layer 100. Furthermore, the closer the external object 600 is to the upper electrode layer 100, the better. The larger, The greater the change.

[0068] It should be noted that, in order to illustrate the complete capacitor model, the capacitor formed between the lower electrode layer 300 and the system ground terminal 400 was listed above. However, due to and Parallel connection does not participate in voltage division calculation, therefore it is not included in the aforementioned formula. .

[0069] The method for fabricating a mine wind speed and non-contact sensing biomimetic flexible sensor provided by the present invention includes four steps: fabrication of upper electrode layer 100, fabrication of dielectric layer 200, fabrication of lower electrode layer 300, and assembly.

[0070] In the preparation of the upper electrode layer 100: firstly, a mold for integrally molding the first substrate 110 and the flexible fibers 120 is prepared, and a molding liquid is prepared; then the molding liquid is injected into the mold, and the air bubbles are removed; then the molding is cured; then the cured colloid is taken out of the mold; finally, a first conductive film 130 is processed on the side of the cured colloid where the flexible fibers 120 are located, and the upper electrode layer 100 is obtained.

[0071] Specifically, a mold is prepared using 3D printing equipment. The mold is designed to be the reverse structure of the overall structure of the first substrate 110 and the flexible cilia 120, that is, to prepare pit structures with different sizes (corresponding to multi-level flexible cilia 120).

[0072] Specifically, the molding liquid is preferably a PDMS mixture or a silicone rubber mixture. The ratio of matrix to curing agent in the PDMS mixture is 20:1 or 30:1, and the ratio of matrix to curing agent in the silicone rubber mixture is 1:1, in order to obtain a more flexible structural property.

[0073] Specifically, during the degassing operation, the mold containing the molding liquid is placed in a vacuum drying oven for degassing treatment, and the degassing time is not less than 3 hours.

[0074] Specifically, during the curing process, the mold after the air bubbles have been removed is placed in an oven and kept there for 3 hours to form a cured colloid.

[0075] Specifically, the first conductive film 130 is processed by ion sputtering or spraying a conductive mixture.

[0076] The dielectric layer 200 is preferably made of insulating silicone or ionic dielectric material, wherein the ionic dielectric material is made of a mixture of ionic liquid and polymer framework.

[0077] In the preparation of the lower electrode layer 300: firstly, a planar thin film is prepared as the second substrate 310, and then a second conductive film 320 is processed on one side surface of the second substrate 310 to obtain the lower electrode layer 300.

[0078] Specifically, when preparing planar thin films, finished products can be used directly, or PDMS mixtures can be cast into shape.

[0079] Specifically, the second conductive film 320 is formed by ion sputtering or spraying a conductive mixture.

[0080] During assembly: the upper electrode layer 100, the dielectric layer 200, and the lower electrode layer 300 are bonded and fixed in sequence.

[0081] Specifically, the bonding and fixation between adjacent layers is achieved by spin-coating a thin layer of PDMS mixture onto the bonding surface.

[0082] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the present invention. Although detailed descriptions have been provided with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments, and they should all be covered within the protection scope of the claims.

Claims

1. A mine-used wind speed and non-contact sensing bionic flexible sensor, characterized in that, include: The upper electrode layer (100) includes a first substrate (110) and flexible cilia (120) disposed on the top surface of the first substrate (110). The top surface of the first substrate (110) and the flexible cilia (120) are jointly covered with a first conductive film (130). The upper electrode layer (100) is used as a resistance test layer to measure wind speed and as a voltage test layer to realize non-contact proximity detection. A dielectric layer (200) is fixedly connected below the upper electrode layer (100); The lower electrode layer (300) is fixedly connected below the dielectric layer (200). The lower electrode layer (300) includes a second substrate (310) and a second conductive film (320). The second conductive film (320) covers the top or bottom surface of the second substrate (310). The lower electrode layer (300) is used as an excitation electrode layer to generate an excitation electric field.

2. The mine-used wind speed and non-contact sensing bionic flexible sensor according to claim 1, characterized in that, The first substrate (110) is made of a flexible elastomer material.

3. The mine-used wind speed and non-contact sensing bionic flexible sensor according to claim 1 or 2, characterized in that, The first substrate (110) and the flexible fibers (120) are integrally formed.

4. The mine-used wind speed and non-contact sensing bionic flexible sensor according to claim 1, characterized in that, The flexible cilia (120) are provided in at least two levels, and the length and / or diameter of the flexible cilia (120) of different levels are different.

5. The mine-used wind speed and non-contact sensing bionic flexible sensor according to claim 4, characterized in that, The flexible cilia (120) has two levels, and each level of flexible cilia (120) has multiple rows. The two levels of flexible cilia (120) are arranged alternately, and the flexible cilia (120) in adjacent rows are staggered.

6. The mine-used wind speed and non-contact sensing bionic flexible sensor according to claim 1, characterized in that, The first substrate (110) and the second substrate (310) are both fixedly connected to the dielectric layer (200) by adhesive bonding.

7. A method for preparing a mine-used wind speed and non-contact sensing bionic flexible sensor, characterized in that, Includes the following steps: Preparation of the upper electrode layer (100): First, a mold for integrally molding the first substrate (110) and flexible fibers (120) is prepared, and a molding liquid is prepared; then, the molding liquid is injected into the mold and the air bubbles are removed, followed by curing and molding, and then the cured colloid is taken out from the mold. Finally, a first conductive film (130) is processed on the side of the cured colloid with flexible fibers (120) to obtain the upper electrode layer (100). Fabrication of the dielectric layer (200); Preparation of the lower electrode layer (300): First, a planar thin film is prepared as the second substrate (310), and then a second conductive film (320) is processed on one side surface of the second substrate (310) to obtain the lower electrode layer (300). Assembly: The upper electrode layer (100), dielectric layer (200) and lower electrode layer (300) are bonded and fixed in sequence.

8. The method for preparing a mine wind speed and non-contact sensing biomimetic flexible sensor according to claim 7, characterized in that, The molding liquid is a polydimethylsiloxane mixture, and the ratio of the matrix to the curing agent of the polydimethylsiloxane mixture is 20:1 or 30:

1. Alternatively, the molding liquid is a silicone rubber mixture, and the ratio of the matrix to the curing agent in the silicone rubber mixture is 1:

1.

9. The method according to claim 7, wherein the method is characterized by, The dielectric layer (200) is made of insulating silicone. Alternatively, the dielectric layer (200) may be prepared using an ionic dielectric material, which is a mixture of an ionic liquid and a polymer framework.

10. The method according to claim 7, wherein, The first conductive film (130) and the second conductive film (320) are both processed by ion sputtering or spraying conductive mixture.

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