Flexible tactile sensors and methods for high hydrostatic pressure environments, underwater robots

Abstract

This invention discloses a flexible tactile sensor and method for use in high hydrostatic pressure environments, as well as an underwater robot. The sensor includes an upper flexible electrode layer, an ion-gel dielectric layer, and a lower flexible electrode layer, with the ion-gel dielectric layer disposed between the upper and lower flexible electrode layers. The ion-gel dielectric layer has a fully open-pore porous framework structure. This invention exhibits high hydrostatic pressure adaptability, enabling the measurement of contact force under hydrostatic pressure. It demonstrates excellent environmental adaptability and precise tactile sensing capabilities in deep-sea high hydrostatic pressure environments.

Description

Technical Field

[0001] This invention specifically relates to a flexible tactile sensor and method for use in high hydrostatic pressure environments, and an underwater robot. Background Technology

[0002] With the increasing demand for marine resource development, the tactile sensing capabilities of deep-sea underwater equipment have become an important direction for technological development. However, the application of existing flexible tactile sensors in deep-sea environments is limited by several challenges, including signal distortion and equipment damage caused by extreme hydrostatic pressure, ion interference in aquatic environments, and chemical corrosion of materials. Most existing sensors are only adaptable to shallow water environments and cannot meet the high-pressure requirements of deep-sea environments. Furthermore, traditional rigid robots, lacking flexible tactile sensing, struggle to grasp fragile objects and perform delicate operations. Simultaneously, robotic actuators lacking tactile sensing systems struggle to acquire information about the properties of the objects they grasp, preventing them from accurately and precisely manipulating small, soft, and fragile objects in extreme deep-sea environments.

[0003] Therefore, developing a flexible tactile sensor that can operate reliably in the high hydrostatic pressure environment of the deep sea, is sensitive to contact force, and adapts to complex environments is crucial for advancing deep-sea resource exploration. Summary of the Invention

[0004] The purpose of this invention is to provide a flexible tactile sensor and method for high hydrostatic pressure environments, as well as an underwater robot, which has high hydrostatic pressure adaptability, can measure contact force under hydrostatic pressure, and has excellent environmental adaptability and precise tactile perception capabilities in the deep-sea high hydrostatic pressure environment.

[0005] The technical solution adopted in this invention is:

[0006] A flexible tactile sensor for use in high hydrostatic pressure environments includes an upper flexible electrode layer, an ion gel dielectric layer, and a lower flexible electrode layer. The ion gel dielectric layer is disposed between the upper and lower flexible electrode layers. The ion gel dielectric layer has a fully open-pore porous framework structure, meaning that all pores are open and connected to the external water environment, and there are no closed pores inside the ion gel.

[0007] Preferably, both the upper flexible electrode layer and the lower flexible electrode layer include a polyimide (PI) flexible substrate and a copper electrode, with the copper electrode disposed on the polyimide (PI) flexible substrate and connected to the ion gel dielectric layer.

[0008] Preferably, the upper flexible electrode layer and the lower flexible electrode layer are bonded to both sides of the ion gel dielectric layer by conductive silver paste adhesive.

[0009] Preferably, the porous framework structure of the ion gel dielectric layer includes an array of biomimetic porous ion gels; the biomimetic porous ion gel is a completely hydrophobic material.

[0010] Biomimetic porous ionogels are produced by pouring ionogel liquid into a sacrificial framework mold. The uncured ionogel liquid is then extracted through vacuum and immersed into all the pores of the mold. After curing, the mold is dissolved to achieve the fully open-pore porous framework structure of the ionogel material itself.

[0011] The mold is a sugar cube mold. Sugar cubes are used only as a sacrificial mold and are not used for fixation. Other water-soluble materials can also be used as sacrificial skeletons. The mold is completely water-soluble. When the mold dissolves in an aqueous solution, it can achieve an open structure with pores that connect with the external environment.

[0012] Preferably, the biomimetic porous ion gel is arranged on the patterned electrodes on the upper and lower flexible electrode layers, and connected in parallel with the seawater between the electrodes to form a high-capacitance double-layer microcapacitor, namely the porous ion gel capacitor and the seawater capacitor. When contact force is applied, the cations of the ion gel and the seawater move relative to each other with the anions of the ion gel and the seawater, and the capacitance value changes. The contact force of the flexible tactile sensor under high hydrostatic pressure can be measured by the relative change of the capacitance value of the ion gel and the seawater, thus realizing tactile perception.

[0013] A method for fabricating a flexible tactile sensor for use in a high hydrostatic pressure environment as described above includes the following steps:

[0014] Preparation of ion gel precursor solution;

[0015] The obtained precursor solution was ultrasonically mixed for a time T1 and then poured into the mold, allowing the precursor solution to penetrate the mold pores.

[0016] The precursor solution in the mold is solidified to form an ion gel. The ion gel is then placed in deionized water and the mold is removed by ultrasonication to form a biomimetic porous ion gel.

[0017] The obtained biomimetic porous ion gel was integrated with an upper flexible electrode layer and a lower flexible electrode layer using conductive silver paste to complete the sensor assembly, resulting in a flexible tactile sensor for use in high hydrostatic pressure environments.

[0018] The mold is a sacrificial skeleton mold. Uncured ionogel liquid is extracted into all the gaps of the mold through vacuum extraction. After curing, the mold is dissolved to realize the fully open-pore porous skeleton structure of the ionogel material itself.

[0019] Preferably, the specific process for preparing the ion gel precursor solution is as follows: butyl acrylate (BA), methyl methacrylate (MMA), and ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide [BMIM]TFSI are mixed to obtain a first mixed liquid, and nano-SiO2 particles, crosslinking agent polyethylene glycol dimethacrylate, and thermal initiator azobisisobutyronitrile are added to the mixed liquid.

[0020] Preferably, the weight ratio of [BMIM]TFSI:BA:MMA in the first mixed liquid is (6.0~8.0):(1.5~3.0):(0.5~1.0).

[0021] Among them, [BMIM]TFSI refers to 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide; BA refers to butyl acrylate; and MMA refers to methyl methacrylate.

[0022] Preferably, the amount of nano-SiO2 particles added is 1.0~2.0 wt% of the first mixed solution.

[0023] An underwater robot includes a flexible tactile sensor, as described above, for use in high hydrostatic pressure environments, attached to the surface of the robot.

[0024] The beneficial effects of this invention are:

[0025] This invention achieves hydrostatic pressure balance between the inside and outside through a fully open-pore, multi-framework ion gel dielectric layer, exhibiting high hydrostatic pressure adaptability. Simultaneously, the relative change in the double-layer microcapacitor formed by the parallel connection of the ion gel and seawater allows for the measurement of contact force under hydrostatic pressure. It possesses aquatic stability and a self-balancing pore structure, effectively mitigating environmental interference caused by hydrostatic pressure. This enables the sensor to operate normally under 50MPa hydrostatic pressure, detecting contact force unaffected by hydrostatic pressure. It can adapt to deep-sea environments ranging from 0 to 5000 meters, effectively solving the problem of interference from high hydrostatic pressure on sensor signals and structure in deep-sea environments. It achieves accurate measurement of operational contact force, demonstrating exceptional environmental adaptability and precise tactile sensing capabilities in high hydrostatic pressure deep-sea conditions. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of a flexible tactile sensor for use in a high hydrostatic pressure environment according to an embodiment of the present invention.

[0027] Figure 2 This is a schematic diagram of the structure of the upper flexible electrode layer in an embodiment of the present invention.

[0028] Figure 3 This is a schematic diagram of the ion gel dielectric layer arranged in the lower flexible electrode layer in an embodiment of the present invention.

[0029] Figure 4This is a schematic diagram of the principle of a flexible tactile sensor for use in high hydrostatic pressure environments in an embodiment of the present invention.

[0030] In the figure: 1-Upper flexible electrode layer; 101-Upper copper electrode; 102-Upper polyimide flexible substrate; 2-Ion gel dielectric layer; 201-Bionic porous ion gel; 202-Ion gel cation; 203-Ion gel anion; 204-Porous ion gel capacitor; 3-Lower flexible electrode layer; 301-Lower copper electrode; 302-Lower polyimide flexible substrate; 4-Seawater; 401-Seawater cation; 402-Seawater anion; 403-Seawater capacitor. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0032] In the description of this invention, it should be understood that if terms such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, they are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0033] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. They can refer to a mechanical connection or an electrical connection. They can refer to a direct connection or an indirect connection through an intermediate medium, and they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0034] Example 1

[0035] A flexible tactile sensor for use in high hydrostatic pressure environments, such as Figures 1-4 As shown, the sensor includes an upper flexible electrode layer 1, an ion gel dielectric layer 2, and a lower flexible electrode layer 3, with the ion gel dielectric layer 2 sandwiched between the upper flexible electrode layer 1 and the lower flexible electrode layer 3. The ion gel dielectric layer 2 is a fully open-pore porous framework structure, meaning that all pores are open and connected to the external water environment, and there are no closed pores inside the ion gel. The ion gel dielectric layer 2 achieves the balance of hydrostatic pressure inside and outside the ion gel dielectric layer, and bonds the flexible electrode layer 1 and the flexible electrode layer 3 to both sides. The ion gel dielectric layer 2 can support the upper flexible electrode layer 1 and the lower flexible electrode layer 3, and the porous framework structure provides support, maintaining the integrity of the overall structure of the flexible tactile sensor. The ion gel dielectric layer 2 with its porous framework introduces seawater into the porous structure, balancing the hydrostatic pressure inside and outside the porous framework of the flexible tactile sensor. When a contact force is applied, the seawater inside the framework is squeezed out, causing the sensor structure to deform to detect the contact force.

[0036] Furthermore, both the upper flexible electrode layer 1 and the lower flexible electrode layer 3 include a polyimide (PI) flexible substrate and a copper electrode. The copper electrode is arranged on the polyimide (PI) flexible substrate to form a patterned electrode, and the copper electrode is connected to the ion gel dielectric layer 2.

[0037] The upper flexible electrode layer 1 includes an upper polyimide (PI) flexible substrate 102 and an upper copper electrode 101, wherein the upper copper electrode 101 is deposited on the upper polyimide (PI) flexible substrate 102 to create a patterned electrode.

[0038] The lower flexible electrode layer 3 is prepared in the same way as the upper flexible electrode layer 1, including a lower polyimide (PI) flexible substrate 302 and a lower copper electrode 301, wherein the lower copper electrode 301 is deposited on the lower polyimide (PI) flexible substrate 302 to create a patterned electrode.

[0039] Furthermore, the upper flexible electrode layer 1 and the lower flexible electrode layer 3 are bonded to both sides of the ion gel dielectric layer 2 by conductive silver paste adhesive.

[0040] Example 2

[0041] Based on Example 1, the ion gel dielectric layer was further defined, resulting in Example 2 having even better performance.

[0042] Furthermore, the porous framework structure of the ion gel dielectric layer 2 includes biomimetic porous ion gel 201 arranged in an array; the biomimetic porous ion gel 201 is a completely hydrophobic material, which can achieve anti-swelling and inhibition of ion exchange in underwater environment, thereby improving the aquatic stability of the flexible tactile sensor in high hydrostatic pressure environment.

[0043] Biomimetic porous ionogels are produced by pouring ionogel liquid into a sacrificial framework mold. The uncured ionogel liquid is then extracted through vacuum and immersed into all the pores of the mold. After curing, the mold is dissolved to achieve the fully open-pore porous framework structure of the ionogel material itself.

[0044] The mold is a sugar cube mold. Sugar cubes are used only as a sacrificial mold and are not used for fixation. Other water-soluble materials can also be used as sacrificial skeletons. The mold is completely water-soluble. When the mold dissolves in an aqueous solution, it can achieve an open structure with pores that connect with the external environment.

[0045] Furthermore, the biomimetic porous ion gel 201 is arranged on the patterned electrodes on the upper flexible electrode layer 1 and the lower flexible electrode layer 3, and is connected in parallel with the seawater 4 between the electrodes to form a high-capacitance double-layer microcapacitor, namely the porous ion gel capacitor 204 and the seawater capacitor 403. When contact force is applied, the ion gel cations 202 and the seawater cations 401 move relative to the ion gel anions 203 and the seawater anions 402, and the capacitance value changes. The contact force of the flexible tactile sensor under high hydrostatic pressure can be measured by the relative change of the capacitance values ​​of the ion gel and the seawater, thus realizing tactile perception.

[0046] Furthermore, the biomimetic porous ion gel 201 is arranged between the lower copper electrode 301 and the upper copper electrode 101, and is connected in parallel with the seawater 4 between the electrodes to form a high-capacitance double-layer microcapacitor. When contact force is applied, the porous ion gel capacitor 204 and the seawater capacitor 403 move relative to each other, and the capacitance value changes. The contact force of the flexible tactile sensor under high hydrostatic pressure can be measured by the relative change of the capacitance values ​​of the ion gel and the seawater, thus realizing tactile perception.

[0047] A method for fabricating a flexible tactile sensor for use in a high hydrostatic pressure environment as described above includes the following steps:

[0048] Step S1: Prepare the ion gel precursor solution;

[0049] Step S2: After ultrasonic mixing for a time T1 (T1 is 15 min), the precursor solution obtained in step S1 is poured into a sugar cube mold and vacuumed to allow the precursor solution to penetrate the pores of the sugar cube mold.

[0050] Step S3: Cover the sugar cube mold with a glass plate after pouring in the precursor solution and place it in a 70℃ oven for 2 hours to solidify and form an ion gel. Place the ion gel in deionized water and ultrasonically remove the sugar cube mold to form a biomimetic porous ion gel.

[0051] Step S4: Integrate the upper and lower flexible electrodes of the biomimetic porous ion gel obtained in step S3 using conductive silver paste to complete the sensor assembly and obtain a flexible tactile sensor for use in high hydrostatic pressure environments.

[0052] The mold is a sacrificial skeleton mold. Uncured ionogel liquid is extracted into all the gaps of the mold through vacuum extraction. After curing, the mold is dissolved to realize the fully open-pore porous skeleton structure of the ionogel material itself.

[0053] Further, the specific process for preparing the ion gel precursor solution is as follows: mixing the soft monomer butyl acrylate (BA), the hard monomer methyl methacrylate (MMA), and the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide [BMIM]TFSI to obtain a first mixed liquid, and adding nano-SiO2 particles, the crosslinking agent polyethylene glycol dimethacrylate, and the thermal initiator azobisisobutyronitrile to the mixed liquid.

[0054] Furthermore, in step S1, the content of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide [BMIM]TFSI in the first mixed liquid is 60~80wt%, the content of butyl acrylate BA is 15~30wt%, and the content of methyl methacrylate MMA is 5~10wt%, which avoids ionic liquid leakage and maximizes capacitance performance.

[0055] Furthermore, the amount of nano-SiO2 particles added is 1.0~2.0 wt% of the first mixed solution.

[0056] Furthermore, in step S1, 1.5 wt% of SiO2 nanoparticles are added to the precursor solution to enhance the hydrophobic barrier on the surface of the ion gel dielectric layer. The denser hydrophobic interface enhances the water resistance of the ion gel and supports its long-term stability in aquatic environments, thereby supporting the operation of the tactile sensor in the ocean.

[0057] Furthermore, in step S1, a long-chain polymer (PEGDMA) is selected as a chemical crosslinking agent during the preparation of the ion gel. The network structure formed by crosslinking reduces the surface viscosity of the material while maintaining the mechanical properties of the ion gel and reduces the mutual adhesion between the skeletons, thereby shortening the sensor response recovery time.

[0058] In step S1, the ionic gel is prepared by crosslinking hydrophobic ionic liquid and hydrophobic polymer to achieve the completely hydrophobic properties. The completely hydrophobic material has an excellent hydrophobic barrier that can achieve anti-swelling and inhibit ion exchange, thereby improving the electrical stability of the sensor.

[0059] The ion gel dielectric layer uses hydrophobic soft monomers combined with hydrophobic hard monomers. The mechanical and electrical properties of the flexible tactile sensor are adjustable through crosslinking density, thereby improving the sensitivity of the flexible tactile sensor.

[0060] The fully hydrophobic ionogel prepared in steps S1, S2, and S3 can be used as a sensing functional layer. The hydrophobic ionogel exhibits anti-swelling properties underwater, inhibiting ion diffusion. Its biomimetic fully open-pore structure allows for internal and external hydrostatic pressure balance. During this process, the relative change in capacitance between the ionogel and seawater in parallel can be measured to determine the magnitude of the contact force, thus enabling tactile perception.

[0061] An underwater robot with a flexible tactile sensor, as described above, for use in high hydrostatic pressure environments, attached to the surface of the robot's gripper.

[0062] The working principle of this invention is as follows: Figures 1-4 As shown, the biomimetic deep-sea tactile sensor includes an upper flexible electrode layer 1, an ion gel dielectric layer 2, and a lower flexible electrode layer 3.

[0063] Both the upper flexible electrode layer 1 and the lower flexible electrode layer 3 are patterned electrodes obtained by depositing metallic copper (Cu) on a polyimide (PI) flexible substrate to ensure the conductivity of the sensor under high voltage conditions.

[0064] The upper flexible electrode layer 1 and the lower flexible electrode layer 3 are bonded together with conductive silver paste. After curing, they are integrated on both sides of the ion gel dielectric layer 2 to complete the sensor assembly.

[0065] The ion gel dielectric layer 2 is designed as a fully open-pore porous framework structure, supporting the upper flexible electrode layer 1 and the lower flexible electrode layer 3 on both sides, which can effectively balance the internal and external hydrostatic pressure and reduce environmental interference in tactile perception.

[0066] like Figure 4 As shown, when the tactile sensor is subjected to external force, the open structure of the ion gel dielectric layer 2 discharges the seawater 4 from the pores. That is, the ion gel interacts with the seawater to form a parallel double-layer microcapacitor, the porous ion gel capacitor 204 and the seawater capacitor 403. By measuring the relative change in capacitance, the contact force can be effectively sensed. When the external force is removed, the tactile sensor will return to its original shape due to the mechanical elasticity of the porous ion gel, thus achieving high reliability and durability of the tactile sensor under high hydrostatic pressure.

[0067] The ionogel dielectric layer 2 is composed of a fully hydrophobic open-pore ionogel with anti-swelling properties, which can inhibit ion exchange and support its long-term stability in aquatic environments, thereby supporting the operation of the tactile sensor in the ocean.

[0068] In a further preferred embodiment, the biomimetic porous ion gel 201 combines a hydrophobic polyacrylate network with nano-SiO2 during its preparation, thereby reducing the surface energy of the ion gel, enhancing the hydrophobic barrier on the surface of the dielectric layer 2 of the ion gel, and improving the water resistance and stability of the ion gel.

[0069] In a further preferred embodiment, a long-chain polymer (PEGDMA) is used as a chemical crosslinking agent when preparing the biomimetic porous ion gel 201. The network structure formed by crosslinking reduces the elastic modulus while maintaining the mechanical properties of the ion gel, without affecting the overall performance of the dielectric layer 2 of the ion gel, which is superior to ion gels prepared with short-chain crosslinking agents on the market.

[0070] In a further preferred embodiment, to avoid leakage of the biomimetic porous ion gel 201 ionic liquid and to maximize the capacitance performance, the weight ratio of [BMIM]TFSI:BA:MMA is taken as 8:1.5:0.5 when preparing the precursor solution. At the same time, the appropriate crosslinking density is adjusted to balance the mechanical and electrical properties of the flexible tactile sensor and improve the sensitivity of the flexible tactile sensor.

[0071] In a further preferred embodiment, in a deep-sea environment, seawater 4 permeates into the pores to balance the hydrostatic pressure, forming a microcapacitor in parallel with the ion gel 2 between the electrodes. This microcapacitor utilizes the principle of double-layer capacitance sensing. Figure 4 As shown. When a contact force is applied to the upper surface of the upper flexible electrode layer 1, the seawater is squeezed out of the pores, resulting in seawater capacitance 403. The decrease in the contact area between the ionogel frameworks leads to an increase in the porous ionogel capacitor 204. Increase, such as Figure 4 As shown in (ii). Contact force is detected by measuring the change in relative capacitance between the seawater and the ionogel. The specific formula for calculating the contact force is as follows:

[0072] ;

[0073] in, For the sensor output capacitor, The operating contact force (the operating contact force is the reaction force felt by the sensor when it is attached to the robotic arm for operation, such as grasping an object; the principle is to balance the influence of seawater hydrostatic pressure on the sensor, so as to realize the measurement of the contact force during operation without being affected by seawater hydrostatic pressure under high hydrostatic pressure). is the relative permittivity of the ionogel. The vacuum permittivity, Porosity The area of ​​the flexible electrode, For dielectric layer thickness, E 凝胶The elastic modulus of the ionogel is... B It is a constant in Ashby's equivalent theory that describes the geometric characteristics of porous structures.

[0074] Another aspect of the present invention provides a method for fabricating a flexible tactile sensor for use in high hydrostatic pressure environments, comprising the following steps:

[0075] S1: Prepare an ion gel precursor by mixing soft monomer BA, hard monomer MMA and ionic liquid [BMIM]TFSI, and add nano-SiO2 particles, crosslinking agent PEGDMA and thermal initiator AIBN to the mixed liquid.

[0076] S2: After ultrasonically mixing the precursor solution obtained in step S1 for 15 minutes, pour it into a sugar cube mold and vacuum it to allow the precursor solution to penetrate the pores of the sugar cube. Cover it with a glass plate and place it in a 70°C oven for 2 hours.

[0077] S3: After curing in step S2, the ionogel is placed in deionized water and the sugar template is removed by ultrasonication.

[0078] Preparation of biomimetic porous ionogel dielectric layers;

[0079] S4: The biomimetic porous ion gel dielectric layer obtained in step S3 is integrated with upper and lower flexible electrodes through conductive silver paste to complete the sensor assembly and obtain a flexible ionized sensor for high hydrostatic pressure environment.

[0080] The flexible tactile sensor in this specific embodiment for high hydrostatic pressure environments features an innovative biomimetic porous ionogel dielectric layer with aquatic stability and a self-balancing pore structure, effectively reducing environmental interference caused by hydrostatic pressure. Simultaneously, the sensor operates unaffected under 50 MPa hydrostatic pressure and can accurately detect the gripping contact force on objects of varying hardness. This sensor exhibits environmental adaptability under high hydrostatic pressure and precise tactile sensing capabilities.

[0081] The flexible ionized sensor has a layered structure, including upper and lower flexible electrode layers and an ion gel dielectric layer sandwiched in between. Specifically: the flexible electrode layers are made of a flexible conductive material to ensure the sensor's conductivity under high-pressure environments; the ion gel dielectric layer is composed of a fully hydrophobic open-pore ion gel, whose hydrophobic barrier provides excellent anti-swelling properties and inhibits ion exchange. Combined with the biomimetic fully open-pore structure, it can balance internal and external hydrostatic pressure, reduce environmental interference, and enhance tactile sensing capabilities.

[0082] The core technology of this sensor lies in the use of a fully hydrophobic ionogel to prepare a functional dielectric layer. Through in-situ polymerization of hydrophobic polymers and hydrophobic ionic liquids, the anti-swelling performance and electrical stability are significantly improved. This open-pore ionogel, by introducing seawater into its porous structure, achieves a dynamic balance of hydrostatic pressure inside and outside the framework, ensuring that the initial signal of the tactile sensor is not interfered with by hydrostatic pressure. This improves the accuracy of measuring relative capacitance changes when the porous ionogel is connected in parallel with the ambient liquid, thus enhancing the accuracy of tactile perception.

[0083] Preferably, the structure of the flexible ionized sensor is inspired by deep-sea sponges and is designed as a fully open structure, which facilitates the entry and exit of ambient water into the porous skeleton. The "hydrostatic skeleton" inside the skeleton achieves the balance of hydrostatic pressure inside and outside the ion gel dielectric layer, maintaining the integrity of the overall structure of the tactile sensor.

[0084] Preferably, the flexible ionized sensor enables tactile sensing. When the flexible ionized sensor is subjected to external force, the open structure drains water from the pores, meaning the ion gel interacts with seawater. The seawater and ion gel form a parallel capacitor between the upper and lower electrodes. The relative change in capacitance is measured, thereby effectively sensing structural deformation. When the external force is removed, the tactile sensor will return to its original shape due to the mechanical elasticity of the porous ion gel. Therefore, the tactile sensor has high reliability and durability under high hydrostatic pressure.

[0085] In summary, the ionogel prepared using hydrophobic materials achieves underwater anti-swelling and ion exchange inhibition, while the biomimetic fully open-pore dielectric layer achieves hydrostatic pressure balance. Simultaneously, the relative change in the bilayer microcapacitor formed by the parallel connection of the ionogel and seawater allows for the measurement of contact force under hydrostatic pressure. The sensor's innovative sensing functional layer possesses aquatic stability and a self-balancing pore structure, effectively mitigating environmental interference caused by hydrostatic pressure. This enables the sensor to detect contact force unaffected by hydrostatic pressure up to 50 MPa, demonstrating excellent environmental adaptability and precise tactile sensing capabilities in deep-sea high hydrostatic pressure environments. The flexible tactile sensor for high hydrostatic pressure environments presented in this application exhibits high sensitivity, reaching 0.667 kPa at low pressure (-10 kPa). - ¹ Furthermore, it can be attached to the surface of an underwater robot gripper to accurately measure the operational contact force, providing accurate and reliable tactile sensing data support for deep-sea operations. The flexible tactile sensor of this application for high hydrostatic pressure environments exhibits stability and durability. After long-term (more than 10 days) immersion in water and salt solution environments, the sensor demonstrates stable mechanical, electrical, and environmental performance, ensuring reliability in long-term deep-sea operations.

[0086] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0087] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A flexible tactile sensor for use in high hydrostatic pressure environments, characterized in that: It includes an upper flexible electrode layer (1), an ion gel dielectric layer (2) and a lower flexible electrode layer (3), with the ion gel dielectric layer (2) disposed between the upper flexible electrode layer (1) and the lower flexible electrode layer (3); the ion gel dielectric layer (2) is a fully open-pore porous framework structure. The porous framework structure of the ion gel dielectric layer (2) includes a biomimetic porous ion gel (201) arranged in an array. The biomimetic porous ion gel (201) is arranged on the patterned electrodes on the upper flexible electrode layer (1) and the lower flexible electrode layer (3), and is connected in parallel with the seawater (4) between the electrodes to form a high-capacitance double-layer microcapacitor, namely the porous ion gel capacitor (204) and the seawater capacitor (403). When the contact force is applied, the cations of the ion gel and the seawater move relative to each other with the anions of the ion gel and the seawater, and the capacitance value changes. The contact force of the flexible tactile sensor under high hydrostatic pressure can be measured by the relative change of the capacitance value of the ion gel and the seawater, so as to realize tactile perception.

2. The flexible tactile sensor for high hydrostatic pressure environments as described in claim 1, characterized in that: Both the upper flexible electrode layer (1) and the lower flexible electrode layer (3) include a polyimide flexible substrate and a copper electrode. The copper electrode is arranged on the polyimide flexible substrate and is connected to the ion gel dielectric layer (2).

3. The flexible tactile sensor for high hydrostatic pressure environments as described in claim 1 or 2, characterized in that: The upper flexible electrode layer (1) and the lower flexible electrode layer (3) are bonded to both sides of the ion gel dielectric layer (2) by conductive silver paste adhesive.

4. The flexible tactile sensor for high hydrostatic pressure environments as described in claim 1, characterized in that: The biomimetic porous ionogel (201) is a completely hydrophobic material.

5. A method for fabricating a flexible tactile sensor for a high hydrostatic pressure environment as described in any one of claims 1 to 4, characterized in that, Includes the following steps: Preparation of ion gel precursor solution; The obtained precursor solution was ultrasonically mixed for a time T1 and then poured into the mold, allowing the precursor solution to penetrate the mold pores. The precursor solution in the mold is solidified to form an ion gel. The ion gel is then placed in deionized water and the mold is removed by ultrasonication to form a biomimetic porous ion gel. The obtained biomimetic porous ion gel was integrated with an upper flexible electrode layer and a lower flexible electrode layer using conductive silver paste to complete the sensor assembly, resulting in a flexible tactile sensor for use in high hydrostatic pressure environments.

6. The preparation method according to claim 5, characterized in that: The specific process for preparing the ion gel precursor solution is as follows: butyl acrylate, methyl methacrylate and ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide are mixed to obtain a first mixed liquid, and nano-SiO2 particles, crosslinking agent and thermal initiator are added to the mixed liquid.

7. The preparation method according to claim 6, characterized in that: In the first mixed liquid, the content of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide is 60-80 wt%, the content of butyl acrylate is 15-30 wt%, and the content of methyl methacrylate is 5-10 wt%.

8. The preparation method according to claim 6 or 7, characterized in that: The amount of nano-SiO2 particles added is 1.0~2.0 wt% of the first mixed solution.

9. An underwater robot, characterized in that: include: A flexible tactile sensor for high hydrostatic pressure environments, as described in any one of claims 1 to 4, is attached to the surface of a robot.

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