A three-terminal flexible adaptive tactile sensor and manufacturing method

Abstract

The present invention discloses a three-terminal flexible adaptive tactile sensor and a manufacturing method, comprising a first end (1), a second end (2) and a third end (3) from top to bottom; the first end (1) is a surface electrode, used to contact with the outside world to generate electrons; the second end (2) is an intermediate electrode, used to conduct electrons; the third end (3) is a bottom electrode, one end of the first end (1) is connected to the positive electrode of a power supply through a wire, and the other end of the first end (1) is connected to a host computer through a wire; one end of the second end (2) is connected to the host computer; one end of the third end (3) is connected to the negative electrode of the power supply through a wire, and the other end of the third end (3) is connected to the host computer through a wire. The present invention can self-adjust the corresponding modulus according to different pressure conditions, that is, the response is completed in the first stage under different moduli, thereby achieving an adaptive effect.

Description

Technical Field

[0001] The present invention relates to the technical field of flexible sensors, and in particular to a three-terminal flexible adaptive tactile sensor and a manufacturing method thereof. Background Art

[0002] New smart materials with adjustable elastic modulus have wide applications in many fields, such as smart robots, smart wearable devices, smart homes, etc. These materials usually have a special microstructure that enables them to respond to external stimuli (such as temperature, pressure, electric field, etc.), thereby changing their elastic modulus. One type of material with adjustable elastic modulus is magnetorheological elastomer.

[0003] Magnetorheological materials are the most representative materials among smart materials. Magnetorheological elastomers (MRE) are magnetically controlled smart materials that are solidified by adding micron-sized magnetic particles to polymers. Under an external magnetic field, its viscoelasticity and rheological properties will change, which is the so-called magnetorheological effect. Magnetorheological effect is a physical phenomenon that refers to the ability to affect the flow of materials in a magnetic field in some way. The generation of this effect depends on many factors, such as the magnetic field strength, the volume percentage concentration of magnetic medium particles, and the size of medium particles.

[0004] Graphene is a sp 2 A new material in which hybrid connected carbon atoms are tightly stacked into a single-layer two-dimensional honeycomb lattice structure. It has excellent electronic, mechanical, physical and thermal properties, which also make graphene a common basic material in pressure sensor devices. Hexagonal boron nitride (HBN) is an insulating isomorph of graphene, with a lattice mismatch rate of only 1.7% with graphene, and is comparable to graphene in terms of mechanical strength and thermal conductivity. Hybrid devices of graphene and HBN have gradually begun to be widely studied. Due to the van der Waals interaction between graphene and hexagonal boron nitride, this heterojunction also has highly adjustable electronic structure and mechanical properties. The graphene HBN heterojunction is applied in pressure sensors. On the one hand, HBN as a protective layer of graphene can protect graphene from oxidation contamination. On the other hand, in this structure, the current is generated by the tunneling of carriers and increases exponentially with the decrease of the distance between atomic layers.

[0005] The human tactile system is the largest sensory organ in the human body. The skin in different parts has different uses. The fingertips are the most sensitive part of the human skin and have the highest density of tactile corpuscles. They are mainly used to sense the material, texture, softness and hardness of objects. The skin on the arms, soles of the feet and other parts can sense a larger range and can assist the human body in carrying objects and maintaining gait balance. By simulating the self-feedback adjustment function of real skin, objects with different properties can be identified and manipulated more accurately, providing more realistic tactile feedback. Bionic skin with adaptive functions has broad application prospects and can play an important role in robotic operation, medical treatment and rehabilitation, human-computer interaction and manufacturing.

[0006] Existing flexible tactile sensors mainly focus on the precise detection of physical stimuli, including pressure, shear force and strain, in order to obtain better feedback during the robot's grasping or manipulation tasks. However, artificial sensors often lack the ability to perceive and identify the real world when touching the target object. In contrast, human skin, especially fingertips, not only has feeling and weight, but also helps to identify the objects it touches.

[0007] Biological tactile perception involves the detection of static pressure and high-frequency vibrations: slowly adapting (SA) receptors in the skin respond to static pressure, and fast adapting (FA) receptors respond to subtly changing dynamic pressures - the rich frequency information provides a new dimension for understanding the characteristics of interactions and identifying target objects. A representative example is that humans can recognize Braille letters or textile types by gently sliding their fingertips over these objects (textures with surface features). Object recognition can serve as feedback for manipulation - humans pinch an egg more carefully than a plastic ball of the same shape, size and weight, while such discriminating dexterous manipulation remains challenging for robots because they lack touch-based object recognition.

[0008] At present, Shuyun Zhuo et al. prepared heterogeneous ion gels for adaptive pressure sensors, which have both shape and stiffness memory effects by combining the stiffness change and shape memory effect induced by the directional microstructure of PSMA microinclusions. Based on the adjustable stiffness and compressibility, the gel has different pressure-deformation responses. Therefore, the pressure sensor based on ion gel manipulates the microstructure of ion gel by compression and fixation, thereby exhibiting a programmable pressure resistance response. Waner Lin et al. proposed an innovative design of a tactile sensor that integrates the functions of two slow-adapting mechanoreceptors (BSM) in a soft medium, allowing self-decoupled sensing of local pressure and strain at specific locations within the contact interface. Then, a biomimetic multi-information fusion strategy was developed based on the adaptive perception of synergistic multiple deformation properties (material flexibility and compliance) using the BSM sensor combined with the robot's kinesthetic cues. Lin Shao et al. designed a highly integrated MASS that receives optical, electrical and pressure information to generate typical synaptic behaviors to mimic multisensory neurons in the brain. The MASS can collect multiple signals and store information for more than 1000 seconds. At the same time, STP can be converted into LTP by adjusting certain spike conditions. The MASS can not only simulate some basic biological signals independently, but also simulate more complex memory behaviors when external stimulus conditions change. By reshaping the memory to adapt to the changing environment, new reaction conditions will be automatically formed.

[0009] In summary, most of the existing devices are self-adaptive in light brightness by imitating vision. In addition, the existing adaptive tactile sensors are mainly based on the establishment of artificial neural networks to achieve the relationship between the output signal and the softness of the material. Most of them are based on the back-end circuit to establish artificial neural networks to achieve the adaptive effect. However, there are not many devices designed to achieve the adaptive effect based on the properties of the material itself, and it is in a blank stage. Summary of the invention

[0010] In view of the technical problem that the accuracy and resolution of object recognition by tactile sensors in the prior art are low, the present invention proposes a three-terminal flexible adaptive tactile sensor and a manufacturing method. By adopting a new type of intelligent material magnetorheological elastomer and a clever structural design to combine the adaptive mechanism and non-volatile neural morphology, it can eliminate some interference signals caused by vibrations, pulses, etc. to a certain extent, thereby improving the accuracy and resolution of object recognition, and achieving response in the first stage of the corresponding modulus under different pressure stages in a device.

[0011] In order to achieve the above object, the present invention provides the following technical solutions:

[0012] A three-terminal flexible adaptive tactile sensor, comprising a first end 1, a second end 2 and a third end 3 from top to bottom;

[0013] The first end 1 is a surface electrode, used for contacting with the outside world to generate electrons; the second end 2 is an intermediate electrode, used for conducting electrons; the third end 3 is a bottom electrode;

[0014] One end of the first terminal 1 is connected to the positive pole of the power supply through a wire, and the other end of the first terminal 1 is connected to the host computer through a wire; one end of the second terminal 2 is connected to the host computer; one end of the third terminal 3 is connected to the negative pole of the power supply through a wire, and the other end of the third terminal 3 is connected to the host computer through a wire.

[0015] Preferably, the first end 1 comprises a substrate 11 and a microstructure 12 , and an inverted pyramid-shaped microstructure 12 is etched on the lower surface of the substrate 11 .

[0016] Preferably, the height of the microstructure 12 includes a first height and a second height, the first height is 5 mm, and the second height is 10 mm.

[0017] Preferably, a layer of thin film 13 is also grown on the surface of the microstructure 12; the materials of the substrate 11 and the microstructure 12 are magnetorheological elastomers, and the material of the thin film 13 is graphene.

[0018] Preferably, the

[0019] The second end 2 includes a tunneling layer 21 , a first electrode 22 and a dielectric layer 23 .

[0020] Preferably, the material of the tunneling layer 21 is HBN, and the material of the first electrode 22 is graphene; the tunneling layer 21 and the first electrode 22 form a heterojunction.

[0021] Preferably, the dielectric layer 23 is made of PVA ion gel and has an array hole structure.

[0022] Preferably, the material of the third end 3 is graphene.

[0023] The present invention also provides a method for manufacturing a three-terminal flexible adaptive tactile sensor, comprising the following steps:

[0024] S1: Gr-PET is used as the third end 3;

[0025] S2: using the prepared PVA ion gel to prepare a dielectric layer 23 on the upper surface of the third end 3;

[0026] S3: placing a first electrode 22 on the dielectric layer 23;

[0027] S4: placing a tunneling layer 21 on the first electrode 22 to form a second end 2;

[0028] S5: etching on a silicon wafer to obtain an array multi-level inverted pyramid structure mold, using a PE-CVD method to grow graphene nanowalls on the array multi-level inverted pyramid structure mold to obtain a graphene film 13; then pouring a magnetorheological elastomer material onto the graphene film 13, taking it out after curing, to obtain a substrate 11 and a microstructure 12 formed by the magnetorheological elastomer material, thereby forming a first end 1;

[0029] S6: Paste the first end 1 onto the second end 2 to obtain a sensor.

[0030] Preferably, S2 includes:

[0031] S2-1: First, prepare PVA ion gel:

[0032] After mixing water and polyvinyl alcohol in a ratio of 1:9, mechanically stir at 100° for 1 hour until PVA is completely dissolved; then cool to room temperature, add a phosphoric acid solution with a mass fraction of 1.69 g / ml, and stir at room temperature for 2 hours to obtain PVA ion gel;

[0033] S2-2: Place a pore structure template on the upper surface of the third end 3, and add the prepared PVA ion gel into the pores with a dropper, put it into a vacuum chamber to evacuate, and after the air in the PVA ion gel is exhausted, put it into a drying oven and bake it at 40° for 12 hours, take out the pore structure template, and thus form a dielectric layer 23 with a pore structure.

[0034] In summary, due to the adoption of the above technical solution, compared with the prior art, the present invention has at least the following beneficial effects:

[0035] 1. The present invention uses a new type of intelligent material magnetorheological elastomer with adjustable elastic modulus to conform to the carbon nanowall film. By changing the magnetic field intensity, the material can change from an intermediate modulus to a hard / soft state, and the state change is reversible, that is, after the condition is removed, its mechanical properties can be restored to the original state; and through repeated training, the modulus of the material can be adjusted as the external contact pressure changes.

[0036] 2. The present invention senses different objects through sliding pressure, evaluates and processes the collected data, adjusts the modulus of the material accordingly through specific conditions, and then performs repeated training so that it can self-adjust the corresponding modulus when exposed to different external pressures, that is, completes the response in the first stage under different moduli, thereby achieving an adaptive effect.

[0037] 3. The adaptive flexible pressure sensor prepared by the present invention adopts a Gr-HBN heterostructure transferred based on thermal release tape, applies the interlayer quantum tunneling effect of two-dimensional materials to the pressure sensor, and gives full play to the excellent performance of graphene and HBN materials and the exponential tunneling current change of the heterostructure; the heterostructure not only has a good protective effect on the graphene electrode, but also expands the relative change of the current, thereby enhancing the sensitivity and response time of the sensor.

[0038] 4. The conformal multi-level pyramid microstructure carbon nanowall of the present invention is prepared by photolithography process, which ensures the consistency and order of the microstructure, and can prepare a multi-level response structure with 5 microns and 10 microns intersecting, which has the effect of improving the sensitivity of the device; the graphene nanowall with high conductivity can be prepared by PE-CVD growth.

[0039] 5. The present invention adopts a multi-level pyramid microstructure with a certain pre-pressure, the contact area between the top electrode and the HBN layer is increased, the distance between the HBN and graphene atomic layers is reduced, and the intensity of the quantum tunneling effect area will be significantly enhanced to produce a huge current change, thereby greatly improving the device's sensitivity response, detection limit and ability to detect tiny forces. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Schematic diagram of a three-terminal flexible adaptive tactile sensor according to an exemplary embodiment of the present invention.

[0041] Figure 2 Schematic diagram of a three-terminal flexible adaptive tactile sensor according to an exemplary embodiment of the present invention.

[0042] Figure 3 Schematic diagram of a method for manufacturing a three-terminal flexible adaptive tactile sensor according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0043] The present invention is further described in detail below in conjunction with the examples and specific implementation methods. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following examples, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0044] In the description of the present invention, it is necessary to understand that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0045] like Figure 1 As shown, the present invention provides a three-terminal flexible adaptive tactile sensor, comprising a first end 1, a second end 2 and a third end 3 from top to bottom.

[0046] In this embodiment, one end of the first terminal 1 is connected to the positive electrode of the power supply through a wire, and the other end of the first terminal 1 is connected to the host computer through a wire; one end of the third terminal 3 is connected to the negative electrode of the power supply through a wire, and the other end of the third terminal 3 is connected to the host computer through a wire; one end of the second terminal 2 is connected to the host computer. The host computer tests the current value I through the connection between the first terminal 1 and the second terminal 2; the host computer tests the voltage value U through the connection between the second terminal 2 and the third terminal 3; the host computer calculates the contact pressure according to the current value I or the voltage value U.

[0047] In this embodiment, the first end 1 is a surface electrode, which is an end surface in contact with the outside world; the first end 1 includes a substrate 11 and a microstructure 12, the upper surface of the substrate 11 is in contact with the outside world, and the lower surface of the substrate 11 is etched with an inverted pyramid-shaped microstructure 12. The material of the substrate 11 can be a magnetorheological elastomer.

[0048] In this embodiment, the height of the microstructure 12 includes a first height and a second height, for example, the first height is 5 mm and the second height is 10 mm, so that a cross-response structure can be formed to improve the sensitivity of the response. The microstructure 12 is a magnetorheological elastomer.

[0049] In this embodiment, a thin film 13 is also grown on the surface of the microstructure 12; the material of the thin film 13 can be graphene.

[0050] In this embodiment, the magnetorheological effect of the magnetorheological elastomer is utilized to adjust the first end 1 by regulating the magnetic intensity (external pressure), so that the magnetorheological elastomer can undergo a change from an intermediate modulus to a hard / soft state (for example, the soft state is: <2Mpa or 2N / mm2; the intermediate modulus is: 2-5Mpa or 2-5N / mm2; the hard state is: >5Mpa or 5N / mm2), and the state change is reversible, that is, after the external pressure is withdrawn, its mechanical properties can be restored to the original state.

[0051] This embodiment also includes an adaptive training method for a three-terminal flexible adaptive tactile sensor:

[0052] First, when the three-terminal flexible adaptive tactile sensor is not in pressure contact with the outside world, the magnetorheological elastomer is in the first modulus (intermediate modulus); when the first end 1 touches and senses the material, texture, softness and hardness of the object, the computer connected to the sensor records the data collected by it, and divides it into a first pressure range, a second pressure range, and a third pressure range. For example, the first pressure range is 0-10N, the second pressure range is 10-30N, and the third pressure range is 30-50N;

[0053] Then, the magnetorheological elastomer is placed in a first modulus, and a sensing object corresponding to a first pressure range is touched, and the training is repeated multiple times, so that the sensor switches to the first modulus to measure the pressure of the sensing object in the first pressure range;

[0054] By applying a magnetic field at the first end 1 and changing the magnetic field strength, the magnetorheological elastomer is changed from the first modulus to the second modulus (i.e., the magnetorheological elastomer becomes soft), and then the sensing object corresponding to the second pressure range is touched. The training is repeated multiple times so that the sensor switches to the second modulus to measure the pressure of the sensing object in the second pressure range.

[0055] By applying a magnetic field at the first end 1 and changing the magnetic field strength, the magnetorheological elastomer is changed from the first modulus to the third modulus (i.e., the magnetorheological elastomer becomes hard), and then the sensing object corresponding to the third pressure range is touched. The training is repeated many times so that the sensor switches to the third modulus to measure the pressure of the sensing object in the third pressure range.

[0056] In this embodiment, the first end 1 is adjusted accordingly by changing the magnetic field strength, thereby changing the modulus of the sensor, and repeated training is performed so that it can self-adjust the corresponding modulus (first modulus, second modulus, third modulus) when exposed to different external pressures, thereby achieving adaptive tactile perception in which the same sensor can judge different moduli and make corresponding responses.

[0057] In this embodiment, the second end 2 is an intermediate electrode, including a tunneling layer 21 , a first electrode 22 and a dielectric layer 23 .

[0058] The material of the tunneling layer 21 is HBN (hexagonal boron nitride), and the material of the first electrode 22 is graphene. The tunneling layer 21 and the first electrode 22 form a heterojunction, which has a good tunneling response and amplifies the relative change of the current. Due to the van der Waals force interaction between graphene and hexagonal boron nitride to form a heterojunction (an interface region formed by the contact of two different semiconductors), this heterojunction also has highly adjustable electronic structure and mechanical properties.

[0059] The material of the dielectric layer 23 is PVA ion gel and has an array pore structure; PVA ion gel has higher stability, stronger adsorption performance, better degradability and simpler production process than other ion gels; the pore structure design helps to improve its non-volatility, and the pore structure can provide additional space so that the PVA ion gel can maintain its original shape and structure after absorbing water, while reducing the penetration and diffusion of water molecules; in addition, the pore structure can also improve the hydrophilicity of the gel and further improve its non-volatility. The non-volatile memory effect of PVA ion gel is utilized to achieve a neuromorphic effect through the accumulation and transfer of charges.

[0060] In this embodiment, the third end 3 is a second electrode, the material of which is graphene, and an electrode wire (Au) is used to lead out and connect to a power source.

[0061] In this embodiment, the working principle of the three-terminal flexible adaptive tactile sensor is as follows: Figure 2 As shown:

[0062] When the first end 1 and the second end 2 begin to contact, there are 5 electrons in the microstructure 12 of the first end 1, and there is one electron on the first electrode 22 and the second electrode 3 respectively; as the external pressure increases, the contact area between the first end 1 and the second end 2 increases, the number of electrons in the microstructure 12 of the first end 1 increases (6 electrons), and there are three electrons on the first electrode 22 and the second electrode 3 respectively, resulting in a change in the measured current value and a corresponding pressure.

[0063] The present invention adopts a multi-level pyramid microstructure with a certain pre-pressure. As the external pressure increases, the contact area between the first end and the tunneling layer 21 increases, and the distance between the atomic layers of the tunneling layer 21 and the first electrode 22 decreases. The intensity of the quantum tunneling effect area will be significantly enhanced to produce a huge current change, thereby greatly improving the device's sensitivity response, detection limit and ability to detect tiny forces.

[0064] In terms of structure, the present invention combines the adaptive mechanism with the non-volatile neural morphology, and then combines with the data processing module to form an intelligent flexible sensor that integrates sensing, storage and computing. By touching and sensing the material, texture, softness and hardness of the object, the collected data is evaluated and processed, and then the modulus of the material is adjusted accordingly by regulating the magnetic field intensity, thereby changing the range, sensitivity, etc. of the sensor, and repeatedly training is performed so that it can self-adjust the corresponding modulus under different external pressure conditions, thereby realizing adaptive tactile sensing. After the Gr-HBN heterojunction, it has a good tunneling response and expands the relative change of the current. To a certain extent, some interference signals caused by vibrations, pulses, etc. can be eliminated, thereby improving the accuracy and resolution of object recognition. At the same time, the three-terminal output design enables the device to have a variety of signal output modes.

[0065] like Figure 3 As shown, the present invention also provides a method for manufacturing a three-terminal flexible adaptive tactile sensor, which specifically includes the following steps:

[0066] S1: Use Gr-PET as the third end 3.

[0067] In this embodiment, Gr-PET (glass reinforced polyethylene terephthalate) is laser cut to a preset size as the third end 3; then an electrode wire mask is made, and after the electrode wire mask is covered on both ends of the third end 3, Au is sputtered using a magnetron sputtering method as the electrode wire of the third end 3.

[0068] S2: preparing a dielectric layer 23 on the upper surface of the third end 3 .

[0069] S2-1: First, prepare PVA ion gel.

[0070] In this embodiment, water and polyvinyl alcohol (PVA) are mixed in a ratio of 1:9, and mechanically stirred at 100° for 1 hour until the PVA is completely dissolved; then, after cooling to room temperature, a phosphoric acid solution with a mass fraction of 1.69 g / ml is added, and stirred at room temperature for 2 hours to obtain an ion gel liquid; in order to improve its non-volatility, carbon black with a hydrophobic group ratio of 10% is introduced to heat-treat the ion gel liquid (put it in an oven or a hot air circulation oven, and set appropriate heating temperature and time according to experimental conditions and objectives, such as heating at 80° for 1 hour) to make its structure more stable and reduce the possibility of water molecule penetration and diffusion.

[0071] The present invention adopts PVA ion gel prepared by adding 1.69g / ml phosphoric acid solution and 10% carbon black as the dielectric layer. Compared with other ion gels, the PVA ion gel with this ratio has higher stability, stronger adsorption performance, better degradability and simpler production process.

[0072] S2-2: using a pore structure template to form a dielectric layer 23 with a pore structure on the upper surface of the third end 3 of the PVA ion gel.

[0073] First, place the third end 3 on a horizontal plane, place a hole structure template on the upper surface of the third end 3, and add an appropriate amount of prepared PVA ion gel into the hole with a dropper, put it into a vacuum chamber and evacuate it. After the air in the PVA ion gel is exhausted, put it into a drying oven and bake it at 40° for 12 hours (that is, wait for the PVA ion gel to solidify), then take out the hole structure template to obtain the dielectric layer 23.

[0074] S3 : forming a first electrode 22 on the dielectric layer 23 .

[0075] In this embodiment, the thermal release tape and the Gr copper foil are cut to a preset size (the same size as the third electrode 3), and then the thermal release tape is pressed onto the Gr copper foil using a laminating machine, and then the first etching solution (a mixture of 130 ml of water, 10 ml of hydrochloric acid, and 5 ml of hydrogen peroxide) is used to etch the back of the Gr copper foil until it becomes transparent (when the copper foil is etched away, only the thermal release tape and the graphene on the Gr copper foil remain, that is, the thermal release tape Gr is formed, which is transparent, similar to frosted glass), and then transferred to clean water and soaked for 40 minutes, and finally blown dry with a high-purity nitrogen gun to form a first electrode 22, and finally the first electrode 22 is placed on the dielectric layer 23, and the first electrode 22 is also led out with a wire (such as Au).

[0076] S4 : forming a tunneling layer 21 on the first electrode 22 .

[0077] In this embodiment, CVD growth is used to transfer HBN, PMMA (poly methylmethacrylate) is spin-coated as a support layer and cured on a heating plate, HBN on the back of the copper foil is removed by mechanical stripping, a second etching solution (350 ml of water, 10 ml of hydrochloric acid, and 5 ml of hydrogen peroxide) is prepared, the copper foil is cut to a specified size and placed in the etching solution for 5 hours to remove the copper foil, the film is transferred to clean water with PET and soaked for use, the prepared flexible substrate is used to scoop it to the middle electrode area, and it is placed on a heating plate for drying, the device is placed in an acetone solution and soaked to remove PMMA, and finally blown dry with a high-purity nitrogen gun to form a tunneling layer 21, and finally the tunneling layer 21 is placed on the first electrode 22.

[0078] The present invention adopts a Gr-HBN heterostructure transferred based on thermal release tape, applies the interlayer quantum tunneling effect of two-dimensional materials to the pressure sensor, and gives full play to the excellent performance of graphene and HBN materials and the exponential tunneling current change of the heterostructure; the heterostructure not only has a good protective effect on the graphene electrode, but also expands the relative change of the current, thereby enhancing the sensitivity and response time of the sensor.

[0079] S5: Make the first end 1.

[0080] S5-1: Since dust particles on the surface of silicon wafers (wafers are cut into 2*2 sized silicon wafers by laser) will affect the formation of photoresist film, before starting photolithography, the silicon wafers are first ultrasonically cleaned in deionized water, acetone and alcohol for 15 minutes to remove surface impurities; after spin coating photoresist on the clean silicon wafer, it is placed on a heating plate at 100° for 10 minutes to dry, and after drying, it is exposed using a binary exposure machine and developed with a developer to form a square pattern (silicon dioxide).

[0081] S5-2: Use an RIE dry etcher to etch the square pattern (i.e., etch the exposed silicon dioxide), the etching gas is trifluoromethane (CHF3), and then clean the photoresist with acetone and alcohol; then use a third etching solution (potassium hydroxide) to etch the anisotropy of the silicon wafer, and adding isopropanol to the third etching solution can improve the orderliness of the pyramid structure etching; rinse with deionized water and blow dry with a high-purity nitrogen gun to obtain an array multi-level inverted pyramid structure mold.

[0082] S5-3: Using the PE-CVD method, a graphene nanowall is grown on the array multi-level inverted pyramid structure mold to obtain a graphene film 13; then, a magnetorheological elastomer material is poured onto the graphene film 13, and taken out after curing, so that a substrate 11 and a microstructure 12 formed by the magnetorheological elastomer material can be obtained, thereby forming a first end 1. Similarly, the two ends of the first end 1 are led out with wires (such as Au).

[0083] In this embodiment, the height of the microstructure 12 includes a first height and a second height. For example, the first height is 5 mm and the second height is 10 mm. This can form a cross-response structure to improve the sensitivity of the response.

[0084] S6: Use the electrostatic force of the plastic wrap to attach the first end 1 to the tunneling layer 21 to keep the sensor in a good initial state.

[0085] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present invention, and in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A three-terminal flexible adaptive tactile sensor, characterized in that: The invention comprises, from top to bottom, a first end (1), a second end (2) and a third end (3); The first end (1) is a surface electrode, used for contacting the outside world to generate electrons; the second end (2) is an intermediate electrode, used for conducting electrons; and the third end (3) is a bottom electrode; One end of the first end (1) is connected to the positive electrode of the power supply through a wire, and the other end of the first end (1) is connected to the host computer through a wire; one end of the second end (2) is connected to the host computer; one end of the third end (3) is connected to the negative electrode of the power supply through a wire, and the other end of the third end (3) is connected to the host computer through a wire; The first end (1) comprises a substrate (11) and a microstructure (12); an inverted pyramid-shaped microstructure (12) is etched on the lower surface of the substrate (11); a layer of thin film (13) is also grown on the surface of the microstructure (12); the material of the substrate (11) and the microstructure (12) is a magnetorheological elastomer, and the material of the thin film (13) is graphene; The second end (2) comprises a tunneling layer (21), a first electrode (22) and a dielectric layer (23); the material of the tunneling layer (21) is HBN, and the material of the first electrode (22) is graphene; the tunneling layer (21) and the first electrode (22) form a heterojunction; the material of the dielectric layer (23) is PVA ion gel and has an array hole structure; The material of the third end (3) is graphene.

2. A three-terminal flexible adaptive tactile sensor as claimed in claim 1, characterized in that: The height of the microstructure (12) includes a first height and a second height, the first height is 5 mm, and the second height is 10 mm.

3. A method for manufacturing a three-terminal flexible adaptive tactile sensor according to any one of claims 1 to 2, characterized in that: The following steps are involved: S1: Gr-PET is used as the third end (3); S2: using the prepared PVA ion gel to prepare a dielectric layer (23) on the upper surface of the third end (3); S3: placing a first electrode (22) on the dielectric layer (23); S4: placing a tunneling layer (21) on the first electrode (22) to form a second end (2); S5: etching on a silicon wafer to obtain an array multi-level inverted pyramid structure mold, using a PE-CVD method to grow graphene nanowalls on the array multi-level inverted pyramid structure mold to obtain a graphene film (13); then pouring a magnetorheological elastomer material onto the graphene film (13), and taking it out after curing to obtain a substrate (11) and a microstructure (12) formed by the magnetorheological elastomer material, thereby forming a first end (1); S6: Paste the first end (1) onto the second end (2) to obtain a sensor.

4. The method for manufacturing a three-terminal flexible adaptive tactile sensor according to claim 3, characterized in that: The step S2 comprises: S2-1: First, prepare PVA ion gel: After mixing water and polyvinyl alcohol in a ratio of 1:9, mechanically stir at 100° for 1 hour until PVA is completely dissolved; then cool to room temperature, add a phosphoric acid solution with a mass fraction of 1.69 g / ml, and stir at room temperature for 2 hours to obtain PVA ion gel; S2-2: Place a pore structure template on the upper surface of the third end (3), add the prepared PVA ion gel into the pores with a dropper, put it into a vacuum chamber to evacuate, and after the air in the PVA ion gel is exhausted, put it into a drying oven and bake it at 40° for 12 hours, take out the pore structure template, and thus form a dielectric layer (23) with a pore structure.

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