A flexible tactile sensor unit based on annular spiral fiber and a preparation method thereof

Abstract

The present invention discloses a flexible tactile sensor unit based on annular spiral fibers and a preparation method thereof, comprising a base layer, a support layer, a tactile sensing layer and an electrode layer, wherein the support layer covers the base layer; the tactile sensing layer comprises X×Y annular spiral fiber units distributed on the support layer; the electrode layer is arranged on the support layer and is used as a signal output lead to connect the X×Y annular spiral fiber units. The flexible tactile sensor unit based on annular spiral sensitive fibers of the present invention has a large degree of design freedom, and array blocks of different sizes and sizes can be designed according to needs. At the same time, the structural surfaces of different regular and irregular carriers are arranged and assembled into a splicable array structure, which can be expanded into different types of tactile sensing arrays and has stronger portability.

Description

Technical Field

[0001] The present invention belongs to the technical field of sensors, and in particular relates to a flexible tactile sensor unit based on annular spiral fibers and a preparation method thereof. Background Art

[0002] In recent years, tactile sensors with high flexibility, large area and high stability have received more and more attention in the fields of robot electronic skin, health monitoring, human-computer interaction, master-slave hand coordination system, etc. The development trend of today's intelligent society has put forward higher requirements for the ability of tactile sensing devices to obtain information. The metal foil pressure sensors used in rigid devices and their systems are currently difficult to meet the requirements of being adaptable, wearable and portable in terms of flexibility. The flexible tactile sensors in the field of flexible electronic skin are friendly, reliable and safe with human skin, which makes them widely studied and applied.

[0003] The sensing mechanism of tactile sensors includes a variety of sensitive mechanisms or sensitive effects, such as resistive, capacitive, piezoelectric, etc. Resistive tactile sensors obtain tactile sensing information through changes in device resistance, and have the characteristics of easy signal collection and simple device structure. At the same time, the advantage of easy large-scale integrated design gives it the potential for scalability and large area, and has broad application prospects in system integration, device arraying and chipization. Domestic and foreign scholars have proposed and designed many devices and array structures for tactile sensor units and their arrays, but many structures are difficult to take into account both bending and stretching characteristics. At the same time, there are certain problems in performance such as sensitivity, detection limit and stability, which restricts the application of resistive tactile sensors. Summary of the invention

[0004] The object of the present invention is to provide a flexible tactile sensor unit based on annular spiral fibers to overcome the above technical problems.

[0005] The above technical objectives of the present invention are achieved through the following technical solutions:

[0006] A flexible tactile sensor unit based on annular spiral fibers, characterized by comprising:

[0007] Basal layer;

[0008] A support layer, covering the base layer;

[0009] A tactile sensing layer, comprising X×Y annular spiral fiber units distributed on the support layer;

[0010] The electrode layer is arranged on the support layer and is used as a signal output lead to connect X×Y annular spiral fiber units.

[0011] Furthermore, the base layer is made of fabric material, and the fabric material is selected from one of lycra fabric, cotton-wrapped spandex fabric, polyester fabric, cotton fabric, nylon fabric, modal, and strong fiber fabric.

[0012] Furthermore, the support layer is made of a rubber-based polymer material, and the rubber-based polymer material is selected from one of silicone rubber and polydimethylsiloxane.

[0013] Furthermore, the annular spiral fiber unit includes an outer spiral and an inner spiral that spirals along the outer spiral, the end points of the outer spiral and the inner spiral are connected by a transverse short fiber, the starting point of the outer spiral is connected to the electrode layer by a longitudinal fiber, and the starting point of the inner spiral is connected to the electrode layer by a transverse fiber.

[0014] Furthermore, the annular spiral fiber unit includes a fiber substrate layer and a rubber-based polymer layer wrapping the fiber substrate layer, and the rubber-based polymer layer is filled with strain-sensitive material.

[0015] Furthermore, the strain sensitive material is selected from two of zero-dimensional sensitive materials, one-dimensional sensitive materials and two-dimensional sensitive materials; the zero-dimensional sensitive material is selected from one of carbon black particles, gold nanoparticles, silver nanoparticles, copper nanoparticles, polyaniline nanoparticles, and polypyrrole nanoparticles; the one-dimensional sensitive material is selected from one of carbon nanotubes, carbon nanofibers, gold nanowires, silver nanowires, zinc oxide nanowires, polyaniline nanowires, polypyrrole nanowires, and polyaniline nanofibers; the two-dimensional sensitive material is selected from one of graphene nanosheets, graphene oxide nanosheets, polyaniline nanosheets, and polypyrrole nanosheets.

[0016] Furthermore, the electrode layer is composed of X transverse conductive fibers and Y longitudinal conductive fibers which are cross-arranged vertically to connect the X×Y annular spiral fiber units.

[0017] Furthermore, the conductive fiber comprises a fiber substrate and a rubber-based polymer wrapping the fiber substrate, and the rubber-based polymer is filled with a conductive material.

[0018] Furthermore, the conductive material is selected from a two-phase conductive material composed of at least one of carbon black particles, gold nanoparticles, silver nanoparticles, and copper nanoparticles.

[0019] Another object of the present invention is to provide a method for preparing a flexible tactile sensor unit based on annular spiral fibers, characterized in that it comprises the following steps:

[0020] Material preparation: Soak the fiber substrate in ethanol and deionized water to clean it, dry it at room temperature and set aside;

[0021] Preparation of conductive fiber: dissolve the conductive material in naphtha in proportion, ultrasonically treat for 0.5-2h, magnetically stir for 0.5-2h, then add the rubber-based polymer material, continue stirring for 1-3h, and obtain a conductive composite material solution; place the fiber substrate in the conductive composite material solution for 5-10min, and vacuum dry at 40-60°C to obtain conductive fiber;

[0022] Preparation of annular spiral fiber unit: dissolve the strain sensitive material in naphtha according to the proportion, ultrasonically treat for 1-3 hours, magnetically stir for 1-3 hours, then add the rubber-based polymer material, continue stirring for 1-3 hours, and obtain the strain sensitive material solution; put the fiber substrate into an annular spiral mold, inject the strain sensitive material solution into the annular spiral mold, vacuum dry at 40-60°C, and then take it out from the mold to obtain the annular spiral fiber unit;

[0023] Preparation of a flexible tactile sensor unit based on annular spiral fibers: a rubber-based polymer layer is prepared on a base layer, X×Y conductive fibers arranged vertically and crossed are placed on the rubber-based polymer layer, and then X×Y annular spiral fiber units are placed on the rubber polymer layer and distributed among the X×Y conductive fibers, and the two starting ends of the annular spiral fiber units are respectively connected to the transverse fibers and the longitudinal fibers, wherein the intersection of the leads of the X×Y conductive fibers is isolated by a rubber-based polymer, and after vacuum drying and curing at 40-60°C, a flexible tactile sensor unit based on annular spiral fibers is obtained.

[0024] Beneficial effects:

[0025] (1) The flexible tactile sensor unit based on the circular spiral sensitive fiber described in the present invention, on the one hand, compared with the flexible tactile sensor unit based on the circular spiral fiber and its array with two-dimensional film or three-dimensional structure, when the flexible tactile sensor unit based on the circular spiral fiber with fabric as carrier senses different types of strain such as stretching, compression, bending, etc., the conductive path formed by the strain sensitive material on the microfiber surface of the fabric changes instantaneously, causing changes in electrical parameters such as resistance. In this way, the textile electronic device that senses tactile information is similar to traditional fabrics, and has better softness, adaptability, and compatibility with the target carrier; on the other hand, the flexible tactile sensor unit based on the circular spiral sensitive fiber has a large degree of design freedom, and array blocks of different sizes and sizes can be designed according to needs. At the same time, the structural surfaces of different regular and irregular carriers are arranged and assembled into a spliced ​​array structure, which can be expanded to a tactile sensing array that senses different pressure ranges, and has stronger portability. Therefore, the flexible tactile sensor based on the circular spiral sensitive fiber and its array can adapt to various types of regular and irregular structural surfaces, and can adapt to strains of different modes such as bending, stretching, curling, etc.

[0026] (2) The sensitive material system in the annular spiral sensitive fiber can be selected from a zero-dimensional sensitive material system, a one-dimensional sensitive material system, and a two-dimensional sensitive material system. Different sensitive material systems can be designed for tactile perception scenarios in different pressure ranges to meet the application requirements of different scenarios.

[0027] (3) The flexible tactile sensor unit based on annular spiral fiber proposed in the present invention comprises X×Y annular spiral sensitive fiber units. On the one hand, each unit can select the same sensitive material or independently select different sensitive materials. On the other hand, each unit has a large degree of freedom in structural design. The number of winding circles, the winding radius, and the spacing between different circles of each unit are flexibly adjustable. The above parameters can be designed according to the specific pressure perception range in different application scenarios. It has the characteristics of adjustable sensitivity and tactile perception range. Each tactile sensor unit independently senses tactile signals, which can realize the perception of single-point tactile information. It can also realize the perception of multi-point tactile information through multiple tactile sensor units on the surface array.

[0028] (4) The process of the present invention is simple, the manufacturing cost is low, and large-scale, scalable sensor array preparation can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of the present invention;

[0030] Figure 2 is a schematic diagram of the connection between the tactile sensor and the electrode layer in the present invention;

[0031] Figure 3 This is a strain resistance curve diagram when the tactile sensor unit described in Example 1 of the present invention senses finger touch pressure multiple times. DETAILED DESCRIPTION

[0032] In the description of the present invention, unless otherwise specified, the terms "upper", "lower", "left", "right", "front", "rear", etc. indicating directions or positional relationships are only for describing the present invention and simplifying the description, and do not indicate or imply that the device or structure referred to must have a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0033] like Figure 1 The flexible tactile sensor unit based on annular spiral fibers comprises a base layer, a support layer, a tactile sensing layer, and an electrode layer.

[0034] Wherein, the base layer is made of fabric material, and the fabric material is selected from one of lycra fabric, cotton-wrapped spandex fabric, polyester fabric, cotton fabric, nylon fabric, modal, and strong fiber fabric;

[0035] Wherein, the support layer covers the base layer, and the support layer is made of a rubber-based polymer material, and the rubber-based polymer material is selected from one of silicone rubber and polydimethylsiloxane;

[0036] Wherein, the tactile sensing layer includes X×Y annular spiral fiber units distributed on the supporting layer, the annular spiral fiber unit includes an outer spiral and an inner spiral that is spiraled along the outer spiral, the end points of the outer spiral and the inner spiral are connected by a transverse short fiber, the starting point of the outer spiral is connected to the electrode layer by a longitudinal fiber, and the starting point of the inner spiral is connected to the electrode layer by a transverse fiber; the annular spiral fiber unit includes a fiber substrate layer and a rubber-based polymer layer that wraps the fiber substrate layer, and the rubber-based polymer layer is filled with strain sensitive material, wherein, The strain sensitive material is selected from two of a zero-dimensional sensitive material, a one-dimensional sensitive material and a two-dimensional sensitive material; the zero-dimensional sensitive material is selected from one of carbon black particles, gold nanoparticles, silver nanoparticles, copper nanoparticles, polyaniline nanoparticles, and polypyrrole nanoparticles; the one-dimensional sensitive material is selected from one of carbon nanotubes, carbon nanofibers, gold nanowires, silver nanowires, zinc oxide nanowires, polyaniline nanowires, polypyrrole nanowires, and polyaniline nanofibers; the two-dimensional sensitive material is selected from one of graphene nanosheets, graphene oxide nanosheets, polyaniline nanosheets, and polypyrrole nanosheets;

[0037] The electrode layer is arranged on the support layer and is used to connect X×Y annular spiral fiber units as a signal output lead. The electrode layer is composed of X transverse conductive fibers and Y longitudinal conductive fibers that are cross-arranged vertically to connect the X×Y annular spiral fiber units. The conductive fibers include a fiber substrate and a rubber-based polymer that wraps the fiber substrate. The rubber-based polymer is filled with a conductive material, and the conductive material is selected from a two-phase conductive material composed of at least one of carbon black particles, gold nanoparticles, silver nanoparticles, and copper nanoparticles.

[0038] The above-mentioned method for preparing a flexible tactile sensor unit based on annular spiral fibers comprises the following steps:

[0039] Material preparation: Soak the fiber substrate in ethanol and deionized water to clean it, dry it at room temperature and set aside;

[0040] Preparation of conductive fiber: dissolve the conductive material in naphtha in proportion, ultrasonically treat for 0.5-2h, magnetically stir for 0.5-2h, then add the rubber-based polymer material, continue stirring for 1-3h, and obtain a conductive composite material solution; place the fiber substrate in the conductive composite material solution for 5-10min, and vacuum dry at 40-60°C to obtain conductive fiber;

[0041] Preparation of annular spiral fiber unit: dissolve the strain sensitive material in naphtha according to the proportion, ultrasonically treat for 1-3 hours, magnetically stir for 1-3 hours, then add the rubber-based polymer material, continue stirring for 1-3 hours, and obtain the strain sensitive material solution; put the fiber substrate into an annular spiral mold, inject the strain sensitive material solution into the annular spiral mold, vacuum dry at 40-60°C, and then take it out from the mold to obtain the annular spiral fiber unit;

[0042] Preparation of a flexible tactile sensor unit based on annular spiral fibers: a rubber-based polymer layer is prepared on a base layer, X×Y conductive fibers arranged vertically and crossed are placed on the rubber-based polymer layer, and then X×Y annular spiral fiber units are placed on the rubber polymer layer and distributed among the X×Y conductive fibers, and the two starting ends of the annular spiral fiber units are respectively connected to the transverse fibers and the longitudinal fibers, wherein the intersection of the leads of the X×Y conductive fibers is isolated by a rubber-based polymer, and after vacuum drying and curing at 40-60°C, a flexible tactile sensor unit based on annular spiral fibers is obtained.

[0043] The following are specific embodiments:

[0044] Embodiment 1:

[0045] S1: Soak the spandex fabric substrate and the spandex fiber substrate in ethanol and deionized water respectively, clean them, dry them at room temperature and set them aside;

[0046] S2: 0.15 g of carbon black and 0.15 g of silver nanoparticles were dissolved in naphtha, ultrasonically dispersed for 0.5 h, magnetically stirred for 1 h, and then 1.5 g of silicone rubber was added, followed by magnetic stirring for 1.5 h to obtain a carbon black / silver nanoparticle / silicone rubber composite material solution;

[0047] S3: placing the spandex fiber substrate into the carbon black / silver nanoparticle / silicone rubber composite material solution for 5 minutes, and vacuum drying at 40° C. to obtain conductive fibers;

[0048] S4: 0.1 g of graphene nanosheets and 0.05 g of carbon nanotubes were dissolved in naphtha, ultrasonically dispersed for 2 h, magnetically stirred for 1.5 h, and then 2 g of silicone rubber was added, followed by magnetic stirring for 2 h to obtain a graphene nanosheet / carbon nanotube / silicone rubber composite material solution;

[0049] S5: placing the spandex fiber substrate into a ring-shaped spiral mold, injecting a graphene nanosheet / carbon nanotube / silicone rubber composite material solution into the mold, vacuum drying at 50° C., and then taking it out of the mold to obtain a ring-shaped spiral fiber unit;

[0050] S6: A layer of silicone rubber with a thickness of 1 mm is spin-coated on the spandex fabric substrate, and X×Y annular spiral sensitive fiber units and X×Y conductive fiber row and column leads arranged crosswise and vertically are placed on the silicone rubber surface. The two ends of the X×Y fiber units are connected to the row and column leads by conductive fibers respectively, and the intersection of the leads is isolated by silicone rubber. After vacuum drying and curing at 50°C, a flexible tactile sensor unit based on the annular spiral sensitive fiber is obtained.

[0051] like Figure 3 As shown, the strain resistance curve of the prepared flexible tactile sensor unit based on annular spiral fibers remained relatively stable when sensing finger touch pressure multiple times, without any large drift.

[0052] Embodiment 2:

[0053] S1: Soak the spandex fabric substrate and the spandex fiber substrate in ethanol and deionized water respectively, clean them, dry them at room temperature and set them aside;

[0054] S2: 0.15 g of carbon black and 0.15 g of silver nanoparticles were dissolved in naphtha, ultrasonically dispersed for 0.5 h, magnetically stirred for 1 h, and then 1.5 g of silicone rubber was added, followed by magnetic stirring for 1.5 h to obtain a carbon black / silver nanoparticle / silicone rubber composite material solution;

[0055] S3: placing the spandex fiber substrate into the carbon black / silver nanoparticle / silicone rubber composite material solution for 5 minutes, and vacuum drying at 40° C. to obtain conductive fibers;

[0056] S4: 0.1 g of graphene nanosheets and 0.05 g of carbon nanotubes were dissolved in naphtha, ultrasonically dispersed for 2 h, magnetically stirred for 1.5 h, and then 2 g of silicone rubber was added, followed by magnetic stirring for 2 h to obtain a graphene nanosheet / carbon nanotube / silicone rubber composite material solution;

[0057] S5: placing the spandex fiber substrate into a ring-shaped spiral mold, injecting a graphene nanosheet / carbon nanotube / silicone rubber composite material solution into the mold, vacuum drying at 50° C., and then taking it out of the mold to obtain a ring-shaped spiral sensitive fiber;

[0058] S6: A layer of 1 mm thick silicone rubber is spin-coated on the spandex fabric substrate, and X×Y annular spiral sensitive fiber units and X×Y conductive fiber row and column leads arranged vertically and crossed are placed on the silicone rubber surface. The two ends of the X×Y fiber units are connected to the row and column leads by conductive fibers, and the intersection of the leads is isolated by silicone rubber. After vacuum drying and curing at 50°C, a flexible tactile sensor array based on annular spiral sensitive fibers is obtained.

[0059] When the flexible tactile sensor unit based on the annular spiral sensitive fiber described in the embodiment of the present invention senses different tactile information, the strain sensitive material of the sensor unit in the tactile sensing layer causes the conductive network constructed by the sensitive material inside the spiral sensitive fiber to change due to the effects of stretching, compression, extrusion, contact, etc., and outputs a specific resistance signal to complete the acquisition of tactile perception information. The tactile sensor unit includes a plurality of annular spiral sensitive fiber units, and the selection of the sensitive material system in each unit has a large degree of freedom, so that the annular spiral sensitive fiber unit has the characteristics of adjustable sensitivity and tactile perception range, and can realize the perception of single-point, multi-point and planar tactile information. In addition, based on the scalability of the fabric substrate, the area of ​​the fabric substrate can be customized according to actual application requirements, and the number of rows and columns and the number of tactile sensor units can be set synchronously, which has the potential for large-scale, customized design of tactile perception arrays, and is expected to be applied in the fields of robot master-slave hand operating systems, remote operating systems, and intelligent electronic skins.

[0060] In order to make the purpose, technical solution and advantages of the present invention more concise and clear, the present invention is illustrated by the above specific embodiments, which are only used to describe the present invention and cannot be understood as limiting the scope of the present invention. It should be pointed out that any modification, equivalent replacement and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. A flexible tactile sensor unit based on annular spiral fibers, characterized in that: include: A base layer (1), wherein the base layer is made of a fabric material; A support layer (2), covering the base layer; A tactile sensing layer (3), comprising X×Y annular spiral fiber units distributed on the support layer; An electrode layer (4), arranged on the support layer, used as a signal output lead to connect X×Y annular spiral fiber units; The annular spiral fiber unit comprises an outer spiral (31) and an inner spiral (32) that spirals along the outer spiral, the end points of the outer spiral and the inner spiral are connected by a transverse short fiber (33), the starting point of the outer spiral is connected to the electrode layer by a longitudinal fiber (34), and the starting point of the inner spiral is connected to the electrode layer by a transverse fiber (35).

2. A flexible tactile sensor unit based on annular spiral fibers according to claim 1, characterized in that: The support layer is made of rubber-based polymer material.

3. The flexible tactile sensor unit based on annular spiral fibers according to claim 1, characterized in that: The annular spiral fiber unit includes a fiber substrate layer and a rubber-based polymer layer wrapping the fiber substrate layer, wherein the rubber-based polymer layer is filled with a strain-sensitive material.

4. A flexible tactile sensor unit based on annular spiral fibers according to claim 3, characterized in that: The strain sensitive material is selected from two of zero-dimensional sensitive materials, one-dimensional sensitive materials and two-dimensional sensitive materials; the zero-dimensional sensitive material is selected from one of carbon black particles, gold nanoparticles, silver nanoparticles, copper nanoparticles, polyaniline nanoparticles, and polypyrrole nanoparticles; the one-dimensional sensitive material is selected from one of carbon nanotubes, carbon nanofibers, gold nanowires, silver nanowires, zinc oxide nanowires, polyaniline nanowires, polypyrrole nanowires, and polyaniline nanofibers; the two-dimensional sensitive material is selected from one of graphene nanosheets, graphene oxide nanosheets, polyaniline nanosheets, and polypyrrole nanosheets.

5. The flexible tactile sensor unit based on annular spiral fibers according to claim 1, characterized in that: The electrode layer is composed of X transverse conductive fibers and Y longitudinal conductive fibers which are cross-arranged vertically to connect the X×Y annular spiral fiber units.

6. The flexible tactile sensor unit based on annular spiral fibers according to claim 5, characterized in that: The conductive fiber comprises a fiber substrate and a rubber-based polymer wrapping the fiber substrate, wherein the rubber-based polymer is filled with a conductive material.

7. The flexible tactile sensor unit based on annular spiral fibers according to claim 6, characterized in that: The conductive material is selected from at least one of carbon black particles, gold nanoparticles, silver nanoparticles, and copper nanoparticles.

8. A method for preparing a flexible tactile sensor unit based on annular spiral fibers according to any one of claims 1 to 7, characterized in that: The steps include: Material preparation: Soak the fiber substrate in ethanol and deionized water to clean it, dry it at room temperature and set aside; Preparation of conductive fiber: dissolve the conductive material in naphtha in proportion, ultrasonically treat for 0.5-2h, magnetically stir for 0.5-2h, then add the rubber-based polymer material, continue stirring for 1-3h, and obtain a conductive composite material solution; place the fiber substrate in the conductive composite material solution for 5-10min, and vacuum dry at 40-60°C to obtain conductive fiber; Preparation of annular spiral fiber unit: dissolve the strain sensitive material in naphtha according to the proportion, ultrasonically treat for 1-3 hours, magnetically stir for 1-3 hours, then add the rubber-based polymer material, continue stirring for 1-3 hours, and obtain the strain sensitive material solution; put the fiber substrate into an annular spiral mold, inject the strain sensitive material solution into the annular spiral mold, vacuum dry at 40-60°C, and then take it out from the mold to obtain the annular spiral fiber unit; Preparation of a flexible tactile sensor unit based on annular spiral fibers: a rubber-based polymer layer is prepared on a base layer, X×Y conductive fibers arranged vertically and crossed are placed on the rubber-based polymer layer, and then X×Y annular spiral fiber units are placed on the rubber polymer layer and distributed among the X×Y conductive fibers, and the two starting ends of the annular spiral fiber units are respectively connected to the transverse fibers and the longitudinal fibers, wherein the intersection of the leads of the X×Y conductive fibers is isolated by a rubber-based polymer, and after vacuum drying and curing at 40-60°C, a flexible tactile sensor unit based on annular spiral fibers is obtained.

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