A flexible tactile sensing and feedback system and method based on texture recognition

Abstract

The application discloses a flexible tactile sensing and feedback system and method based on texture recognition, which comprises an electrostatic flexible tactile sensor, a feedback actuator and a tactile feedback control circuit, the electrostatic flexible tactile sensor comprises a tactile interaction film for acquiring texture features and a pressure sensor for texture feature conversion; the feedback actuator completes tactile feedback of the texture feature signal acquired by the flexible sensor in the form of vibration; the tactile control system is mainly connected with the electrostatic flexible tactile sensor and the tactile feedback actuator through the feedback control circuit; the tactile feedback actuator has a stimulation reinforcement structure on the contact surface with the human body, which can further enhance the fine feedback of the tactile feeling. The application can effectively identify the texture features and complete the feedback of the fine tactile feeling in the form of vibration, provides effective assistance for the tactile recovery of the disabled, and has important application value in the game industry, especially in the development of virtual reality technology.

Description

Technical Field

[0001] This invention belongs to the field of tactile sensing and feedback technology, specifically relating to a flexible tactile sensing and feedback system and method based on texture recognition. Background Technology

[0002] Flexible haptic feedback technology is a crucial component of human-computer interaction, playing a significant role in virtual reality (VR), augmented reality (AR), robotics, healthcare, and wearable devices. Traditional rigid sensors face limitations in their application on flexible objects or curved surfaces, while flexible sensors, due to their flexibility and adaptability, have become an effective solution to this problem. However, current flexible haptic sensing and feedback systems still face challenges in texture recognition and providing fine-grained haptic feedback. Texture recognition refers to the system's ability to accurately perceive and identify the texture features of an object's surface, including but not limited to roughness and shape. This is essential for achieving more intelligent and realistic haptic feedback. Traditional texture recognition technologies primarily rely on vision or other sensors, which often struggle to achieve accurate recognition on flexible materials or irregularly shaped objects, and fine-grained haptic feedback technologies are also quite lacking.

[0003] The organic integration of texture recognition and tactile feedback is an indispensable and crucial step in the development of tactile reproduction, involving the structural design and fabrication of tactile stimulus mapping in tactile feedback actuators and the design of feedback control circuits. However, most current technological integrations have not yet achieved fine-grained tactile feedback; that is, mapping the magnitude of tactile features under different textures still faces significant challenges, severely impacting the fine-grained feedback of flexible electronic skin when contacting different textures. Therefore, there is an urgent need to develop a flexible tactile sensing system capable of recognizing the texture features of external objects and providing fine-grained feedback. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention aims to provide a flexible tactile sensing and feedback system and method based on texture recognition. By combining a high-performance ionized flexible tactile sensor, a feedback control circuit, and a tactile feedback actuator, it achieves efficient perception and recognition of the texture features of an object surface and can provide accurate tactile feedback based on the recognition results, thereby improving the interactivity, realism, and application value of the tactile system.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a flexible tactile sensing and feedback system based on texture recognition, comprising an ionized flexible tactile sensor, a tactile feedback actuator, and a feedback control circuit. The feedback control circuit is used to convert the capacitive signals of different texture features collected by the ionized flexible tactile sensor into signals of different magnitudes of mechanical vibration of the tactile feedback actuator, thereby realizing tactile feedback.

[0006] The ionized flexible tactile sensor includes an ion membrane disposed between a bottom thermoplastic polyurethane elastomer (TPU) film electrode and a top TPU film electrode. The hierarchical micron-scale structure on the surface of the ion membrane is oriented towards the top TPU film electrode. A mesh spacer layer is disposed between the ion membrane and the top TPU film electrode. A tactile interaction membrane is connected to the top TPU film electrode. The tactile interaction membrane has a microconical protrusion structure. During use, the microconical protrusion structure comes into contact with and rubs against the object to be textured.

[0007] The tactile feedback actuator includes, from top to bottom, a PDMS film inlaid with a tactile stimulation enhancement structure, a vibrator, a copper wire, and a PDMS substrate film, which are connected in sequence. The tactile stimulation enhancement structure has a micron-level protrusion structure, which comes into contact with human skin during use.

[0008] Furthermore, the tactile interaction membrane is a TPU film with a micro-conical protrusion structure; both the bottom TPU film electrode and the top TPU film electrode are integrated structures consisting of a TPU film and an Au electrode. A TPU solution with a thickness of 8μm to 10μm is coated on the non-electrode surface of the top TPU film electrode, and a TPU solution with a thickness of 8μm to 10μm is coated on the periphery of the non-electrode area of ​​the electrode surface of the bottom TPU film electrode, for encapsulation.

[0009] Furthermore, the specific steps for fabricating the ionized flexible tactile sensor are as follows:

[0010] 1) TPU solution preparation:

[0011] TPU particles are mixed with DMF solution to obtain TPU solution;

[0012] 2) Fabrication of tactile interaction membrane:

[0013] TPU solution is poured onto a mold plate with a microconical groove structure and cured to obtain a TPU film with a microconical protrusion structure. The TPU film is then dimensionally etched according to a set shape to obtain a tactile interactive film.

[0014] 3) TPU film electrode fabrication:

[0015] A photomask is fixed on a polytetrafluoroethylene (PTFE) film adhesive surface, electrodes are sputtered, and a TPU solution is spin-coated onto the PTFE film adhesive surface with sputtered electrode patterns. After curing, a TPU film with electrodes is obtained. The TPU film is etched according to a set shape to obtain a TPU film electrode.

[0016] 4) Preparation of ion exchange membranes:

[0017] The TPU, DMF solution and ILs are heated and mixed to obtain a TPU ionic solution, the TPU ionic solution is coated on sandpaper, and solidification is performed to obtain a TPU ionic film with a hierarchical micron structure surface, and the TPU ionic film is etched according to a set shape to obtain a TPU ionic film.

[0018] 5) Spacer layer preparation:

[0019] The TPU solution is spin-coated on a glass sheet, and solidification is performed to obtain a TPU film, and the TPU film is etched according to a set shape to obtain a mesh spacer layer.

[0020] 6) Packaging of the deionization type flexible tactile sensor:

[0021] The bottom TPU film electrode, the ionic film, the mesh spacer layer, the top TPU film electrode and the tactile interaction film are placed from bottom to top for hot pressing packaging to obtain a deionization type flexible tactile sensor.

[0022] Further, in step 1), the mass ratio of TPU and DMF solution is (2-4):10, the rotation speed is 1000 r / min-1500 r / min, the temperature is 100℃-120℃, and the heating and stirring time is 2h-4h;

[0023] In step 2), the film pouring plate is cured under ultraviolet light with a power of 20W-30W for 20min-30min, and the TPU film is cured at a temperature of 70℃-90℃ for 45min-75min;

[0024] In step 3), an A4 paper is used to prepare a mask plate, specifically: the A4 paper is laser cut for 3-5 cycles under the conditions of a power of 3W-5W and a moving speed of 200mm / s-400mm / s;

[0025] When sputtering the electrode: sputter for 200s-300s at a current of 20mA-30mA, and the target material is Au;

[0026] The TPU solution is spin-coated at a rotation speed of 500r / min-1000r / min for 10s-20s, and solidified at a temperature of 70℃-90℃ for 60min-100min;

[0027] In step 4), the TPU, DMF solution and ILs are mixed in a ratio of 2g:(5-10)mL:(1-1.5)g, and stirred at a temperature of 100℃-120℃ and a rotation speed of 1000r / min-1500r / min for 2h-4h to obtain a TPU ionic solution; the TPU ionic solution is coated on sandpaper, and solidified at a temperature of 60℃-80℃ for 3h-5h to obtain a TPU ionic film;

[0028] In step 5), the TPU is spin-coated at a speed of 2500 r / min to 3500 r / min for 10 s to 20 s and cured at a temperature of 70°C to 90°C for 60 min to 100 min to obtain the spacer layer.

[0029] In step 6), when performing the hot-press packaging, the pressure is 10 N to 20 N, the temperature is 60°C to 70°C, and the time is 5 min to 15 min.

[0030] Further, the haptic feedback actuator preparation step is specifically as follows:

[0031] 1) spin-coat the PDMS solution on the substrate to obtain a PDMS film after curing;

[0032] 2) adsorb the copper foil on the surface of the PDMS film and etch to obtain copper wires;

[0033] 3) connect the vibrator and the copper wires, check the connection, and then spin-coat the PDMS solution;

[0034] 4) embed the haptic stimulation reinforcement structure component into the PDMS solution one by one corresponding to the vibrator, and obtain the haptic feedback actuator after heating and curing.

[0035] Further, in step 1), the PDMS solution is prepared by mixing Dow Corning 184 curing agent (B solution) and Dow Corning 184 base fluid (A solution) at a mass ratio of 1:(10-20); the PDMS solution is spin-coated on the substrate at a speed of 500 r / min to 1000 r / min for 10 s to 20 s, and cured at a temperature of 80°C to 100°C for 1 h to 2 h to obtain a PDMS film;

[0036] In step 2), nanosecond laser etching is used, with a power of 3 W to 5 W, a pulse width of 1000 ns, a frequency of 50000 Hz, a speed of 200 mm / s to 400 mm / s, and a cutting cycle of 15 to 25 times.

[0037] Further, the vibrator is a brushless vibration motor with a diameter of 5 mm to 7 mm and a thickness of 2 mm.

[0038] Further, the feedback control circuit includes a capacitance acquisition module, an ESP32 master single-chip microcomputer, a motor driving module, a power module, and a voltage reduction module, wherein the capacitance acquisition module is used to acquire the capacitance signal output by the off-electric flexible tactile sensor and transmit it to the ESP32 master single-chip microcomputer;

[0039] The ESP32 master single-chip microcomputer is used to convert the capacitance signal into an output voltage for controlling the motor driving module;

[0040] The power module is used to power the motor driving module;

[0041] The motor driving module receives the voltage change data output by the ESP32 master single-chip microcomputer and transmits to the voltage reduction module, and the voltage reduction module is used for reducing the voltage to the working voltage of the haptic feedback actuator;

[0042] The change of the output voltage of the motor driving module is controlled by the ESP32 master single-chip microcomputer, and the output voltage is transmitted to the voltage reduction module, and the voltage reduction module reduces the voltage to the working voltage of the haptic feedback actuator.

[0043] Further, the capacitance acquisition module transmits data to the ESP32 master single-chip microcomputer through an IIC communication protocol;

[0044] The ESP32 master single-chip microcomputer is used for processing the capacitance frequency and peak value collected by the capacitance module, and outputting a PWM square wave of an IOA port to control the output voltage of the motor driving module.

[0045] The application also provides a texture recognition method using the above system, and the specific steps are as follows:

[0046] 1) The off-electric flexible tactile sensor is connected with the haptic feedback actuator through the feedback control circuit;

[0047] 2) The convex structure of the haptic interaction film of the off-electric flexible tactile sensor is contacted and rubbed with the object to be identified, and a capacitance signal is obtained, and the off-electric flexible tactile sensor transmits the capacitance signal to the feedback control circuit;

[0048] 3) The feedback control circuit converts the capacitance signal into a vibration signal of the haptic feedback actuator and transmits it to the haptic feedback actuator;

[0049] 4) The vibrator of the haptic feedback actuator vibrates according to the received vibration signal, and the micron-level convex structure on the haptic stimulation reinforcement structure component vibrates under the driving of the vibrator, and the haptic of the object to be identified is fed back to the human skin through vibration.

[0050] Compared with the prior art, the application has at least the following beneficial effects:

[0051] The application provides a flexible tactile sensing and feedback system based on texture recognition, which is provided with an ion film and a tactile interaction film, so that the flexible tactile sensor provided by the application has super-sensitive tactile detection performance and can realize accurate identification of micro texture structure; meanwhile, the tactile feedback actuator of the application is equipped with a tactile stimulation reinforcement structure component, which significantly improves the reproduction ability of skin stimulation and enhances the strength and fineness of tactile feedback; the application uses a capacitive feedback control circuit as a connecting bridge, organically combines the flexible tactile sensor and the tactile feedback actuator, realizes identification of tactile texture and fine mapping of tactile size, and provides users with more abundant and accurate tactile feedback experience.

[0052] Further, the tactile interaction film, the film electrode, the net-shaped spacing layer and the ion film of the flexible tactile sensor are all made of TPU material, so that the material is designed in an integrated manner, the shear resistance of the sensor when rubbing different textures can be effectively enhanced, the delamination phenomenon can be prevented, and the stability of data acquisition can be improved.

[0053] Further, the vibrator of the tactile feedback actuator is combined with the flexible substrate wire to construct a tactile feedback electronic skin, which closely adheres to the human skin; the improvement of the structure of the tactile feedback actuator enhances the reproduction ability of the human skin stimulation; the vibrator and the tactile stimulation reinforcement structure component are connected through a PDMS film to form a tactile feedback actuator with fine feedback.

[0054] Further, the feedback control circuit collects the capacitive signal of the flexible tactile sensor, processes and converts it into a vibration signal of the tactile feedback actuator, realizes the organic combination of the flexible tactile sensor and the tactile feedback actuator, and constructs a complete tactile sensing and feedback system, which can realize identification of tactile texture and fine mapping of tactile size, and provide users with more abundant and accurate tactile feedback experience.

[0055] In summary, the flexible tactile sensing and feedback system based on texture recognition provided by the application has excellent performance in the field of tactile sensing and feedback, and provides strong technical support for the tactile repair of disabled people, the development of virtual reality (VR) in the game industry and other applications. BRIEF DESCRIPTION OF DRAWINGS

[0056] The drawings described herein are used to provide further understanding of the application, constitute a part of the application, and do not constitute an improper limitation on the application, and in the drawings:

[0057] Figure 1 is a schematic view of the flexible tactile sensing system based on texture recognition of the application;

[0058] Figure 2is the unfolded view of the electrostatic flexible tactile sensor of the present application;

[0059] Figure 3 is the schematic view of the sensor cross section;

[0060] Figure 4 is the process flow chart of the tactile feedback execution of the present application;

[0061] Figure 5 is the schematic view of the feedback actuator structure of the present application;

[0062] Figure 6 is the schematic view of the feedback control circuit of the present application.

[0063] In the figure, 1, electrostatic flexible tactile sensor; 2, tactile feedback actuator; 3, feedback control circuit; 4, bottom TPU film electrode; 5, ion film; 6, reticular spacer layer; 7, top TPU film electrode; 8, tactile interaction film; 9, copper wire; 10, nanosecond laser; 11, vibrator; 12, tactile stimulation reinforcement structure component; 13, PDMS base film. DETAILED DESCRIPTION

[0064] The present application will be described in detail below with reference to the accompanying drawings and specific embodiments, which are used to explain the present application, but not as a limitation of the present application.

[0065] Reference Figure 1 The present application provides a flexible tactile sensing and feedback system based on texture recognition, which comprises an electrostatic flexible tactile sensor 1, a tactile feedback actuator 2 and a feedback control circuit 3. The electrostatic flexible tactile sensor 1 and the tactile feedback actuator 2 are connected through the feedback control circuit 3. When the flexible tactile sensing system of the present application works, the electrostatic flexible tactile sensor 1 obtains the capacitance characteristic signal when rubbing with different textures. The feedback control circuit 3 converts the input capacitance characteristic signal of different textures into mechanical vibration signals of different sizes. The tactile feedback actuator 2 receives the mechanical vibration signal output by the feedback control circuit 3 and performs different size mechanical vibration to simulate the tactile effect of different textures, thereby realizing tactile feedback.

[0066] Reference Figure 2 The electrostatic flexible tactile sensor of the embodiment of the present application comprises a bottom TPU film electrode 4, an ion film 5, a reticular spacer layer 6, a top TPU film electrode 7 and a tactile interaction film 8. The above six components are connected in order from bottom to top to form the electrostatic flexible tactile sensor. The bottom TPU film electrode 4 and the top TPU film electrode 7 are both TPU film electrodes composed of electrode sputtering on TPU film. The ion film 5 has irregular microstructure on the surface, which is described in detail in Figure 3The sensor cross-section schematic diagram; the tactile interaction film 8 has micro-cone convex structure, and the convex structure is in contact and friction with the object to be identified in use;

[0067] The bottom TPU film electrode 4, the ion film 5, the net spacing layer 6 and the top TPU film electrode 7 constitute a flexible pressure sensor, the ion film 5 is located between the bottom TPU film electrode 4 and the top TPU film electrode 7, and a hierarchical micron structure is designed on the surface of the ion film to enhance the response ability to pressure change. To ensure the initial capacitance stability, the ion film 5 and the top TPU film electrode 7 are isolated by the net spacing layer 6 to avoid direct contact. When no external force is applied, the net spacing layer 6 ensures that the sensor maintains a stable air capacitance state. Under the action of external force, the top TPU film electrode 7 contacts the ion film 5 to form a nanoscale ion-electric sensing interface, and the capacitance value rapidly changes from air capacitance to double-layer capacitance, significantly enhancing the signal strength of the sensor, thereby realizing sensitive and accurate detection of pressure.

[0068] The microstructure identification mechanism of the present application is based on the interaction of the ion-electric flexible tactile sensor with different roughness surfaces. When the ion-electric flexible tactile sensor contacts and slides on different texture surfaces, vibration is generated between the tactile interaction film 8 and the different texture surface structures due to friction. The flexible pressure sensor provided by the present application has high sensitivity and can capture these vibrations caused by friction and convert them into electrical signals. Because different surfaces have different roughness and texture characteristics, the vibration frequency and intensity are different. Therefore, the ion-electric flexible tactile sensor of the present application can effectively distinguish and identify the surface structure characteristics of the contacted object, and realize accurate identification of the surface structure of different objects.

[0069] Reference Figure 5 The tactile feedback actuator 2 includes a PDMS film embedded with a tactile stimulation reinforcement structure component 12, a vibrator 11, a copper wire 9 and a PDMS base film 13 connected in sequence from top to bottom, and the tactile stimulation reinforcement structure component 12 has a micron-level convex structure which is in contact with human skin in use.

[0070] In the embodiment, the TPU solution is prepared by mixing thermoplastic polyurethane elastomer (TPU) of Easypak with N,N-dimethylformamide solution (DMF solution) of Macclin; the ionic liquid (ILs) is 1-ethyl-3-methylimidazolium trifluoromethanesulfonate solution of Aladdin, 98%.

[0071] Reference Figure 6The principle schematic diagram of the feedback control circuit 3 of the embodiment of the present application, the integrated control circuit includes a capacitive collection module, an ESP32 single-chip microcomputer, an L298N motor drive module, a power module, and an LM2596 voltage reduction module. The capacitive collection module of the feedback control circuit 3 is connected to the input end of the electroluminescent flexible tactile sensor 1, and the output end of the LM2596 voltage reduction module is connected to the tactile feedback actuator 2.

[0072] Reference Figure 2 In one embodiment, the preparation method of the electroluminescent flexible tactile sensor includes the following steps:

[0073] Before each layer is prepared, TPU particles are mixed in a DMF solution at a mass ratio of (2-4):10 using a clean beaker, and then a magnetic stirrer is used to stir at 100-120 DEG C at 1000-1500 r / min for 2-4 h to completely dissolve the particles, thereby obtaining a TPU solution.

[0074] Step 1, tactile interaction film preparation:

[0075] Maxon Cinema 4D software is used to design the structure of the reverse film plate, and a 3D printer is used to manufacture the reverse film plate with the micro-cone groove structure by using additive technology; a 25 mL beaker is cleaned with anhydrous ethanol and dried with a hot hair dryer, and isopropanol solution is poured into the beaker, the reverse film plate is taken out from the 3D printer and placed in the beaker, and then the beaker is placed in an ultrasonic cleaner for ultrasonic treatment for 15-20 min; after the ultrasonic treatment is completed, the reverse film plate is taken out with tweezers, naturally air-dried, and placed in an ultraviolet light curing machine for curing at a power of 20-30 W for 20-30 min; the TPU solution is poured on the cured reverse film plate, placed in a vacuum filtration machine to remove the bubbles in the grooves of the reverse film plate, and then placed on a constant temperature heating table for constant temperature curing at 70-90 DEG C for 45-75 min; the reverse film plate is taken off from the heating table, cooled to room temperature, and the TPU film is peeled off using a plastic tweezer, thereby obtaining the tactile interaction film 8 with the micro-cone convex structure.

[0076] Step 2, TPU film electrode preparation:

[0077] 1) 60mm×60mm glass sheets are cleaned with deionized water and anhydrous ethanol respectively, and then dried with a hot hair dryer; a plastic spatula is used to slowly and evenly glue the PTFE film on the glass sheets;

[0078] 2) A4 paper is adsorbed under the nanosecond laser light output mirror, and the laser light output power is adjusted to 3W~5W according to the pre-designed electrode profile, the moving speed of the laser head is 200mm / min~400mm / min, the pulse width is 1000ns, the frequency is 50000Hz, and the profile cutting cycle is 3~5 times, to obtain a mask plate for magnetron sputtering electrode;

[0079] 3) The mask plate is covered on the glass sheet with PTFE film glue using transparent single-sided tape at the edge of the mask plate, and then placed in the vacuum chamber of the magnetron sputtering machine, the sputtering target is replaced with Au, the current is adjusted to 20mA~30mA, the air is pumped out by opening the vacuum pump, and when the pressure in the vacuum chamber is lowered to 3Pa, the sputtering is performed for 200s~300s, and Au particles are sputtered on the PTFE film glue through the non-shielding part of the mask plate to obtain an electrode pattern;

[0080] 4) The glass sheet with Au electrode sputtered PTFE film glue is fixed on the rotating disc of the spin coater, and the TPU solution is spin coated at a speed of 500r / min~1000r / min for 10s~20s;

[0081] 5) The glass sheet with spin-coated TPU solution is taken out and placed on a constant temperature heating table, and heated at 70℃~90℃ for 60min~100min to solidify the TPU film;

[0082] 6) The solidified TPU film is peeled off from the PTFE film glue using a sharp tweezers to obtain a TPU film electrode.

[0083] Step 3, ion membrane preparation:

[0084] 5mL~10mL DMF solution is transferred to a beaker using a syringe, 2g TPU powder and 1~1.5g ILs are added in sequence; then a magnet is placed in the beaker, and it is moved to a magnetic stirrer, and heated and stirred at a speed of 1000r / min~1500r / min and a temperature of 100℃~120℃ for 2h~4h to uniformly disperse the powder and ions; after uniform dispersion, a TPU ion solution is obtained, which is cooled at room temperature for standby use; take a 1000 mesh~5000 mesh sandpaper, and use double-sided tape to attach it to a 60mm×60mm glass sheet, and cut off the excess sandpaper edges; the TPU solution is coated on the sandpaper, and placed on a constant temperature heating table, and heated at a constant temperature of 60℃~80℃ for 3h~5h to solidify the TPU ion solution on the sandpaper; the TPU ion film is slowly peeled off from the edge of the sandpaper with tweezers, and the thickness is 100μm~250μm.

[0085] Step 4, spacer layer preparation:

[0086] Take a piece of 60mm x 60mm glass sheet cleaned according to step 2-1), fix it on the rotating disc of the spin coater, spin coat the TPU solution at a speed of 2500r / min~3500r / min for 10s~20s; take out the glass sheet and place it on the constant temperature heating table, heat at 70℃~90℃ for 60min~100min to solidify the TPU film; slowly peel off the TPU film from the glass sheet with tweezers to obtain a 10μm~30μm thick TPU spacer layer film.

[0087] Step 5, packaging of the electrostatic flexible tactile sensor:

[0088] 1) According to the designed sensor structure, use 3D additive technology to make a lower hot press mold with a groove profile and an upper hot press mold matched with the groove profile, and clean and solidify the mold according to step 1;

[0089] 2) The bottom TPU film without cutting treatment, the TPU film with sputtering electrode, the TPU ion film and the TPU spacer layer film are sequentially etched according to the pre-designed profile on the nanosecond laser 10, the laser moving speed is 100mm / min~500mm / min, the power is 5W, the pulse width is 1000ns, and the frequency is 50000Hz, wherein the tactile interaction film, the TPU film with sputtering electrode and the TPU ion film are cut 15~25 times in a cycle, and the spacer layer film is cut 5~10 times in a cycle, and the laser etching obtains the tactile interaction film 8, the bottom TPU film electrode 4, the top TPU film electrode 7, the ion film 5 with a diameter of 4mm~8mm and the net-shaped spacer layer 6;

[0090] 3) Put the following materials in the lower hot press mold in turn: the bottom TPU film electrode 4 with a thickness of 8μm~10μm TPU solution scraped on the electrode surface periphery, the ion film 5, the net-shaped spacer layer 6, the top TPU film electrode 7 with a thickness of 8μm~10μm TPU solution scraped on the non-electrode surface, and the tactile interaction film 8 with micro-cone convex structure;

[0091] 4) Assemble the upper hot press mold, heat press at a pressure of 10N~20N and a constant temperature of 60℃~70℃ for 5min~15min, complete the packaging of the electrostatic flexible tactile sensor, and the packaged sensor can effectively improve the shear resistance of the sensor in friction and prevent the occurrence of delamination (the sensor cross-sectional schematic diagram is shown in Figure 3 b), and the structure of the traditional sensor prone to delamination is shown in Figure 3 a.

[0092] Step 6, preparation of tactile feedback actuator:

[0093] The PDMS solution is prepared by mixing the solution of Dow Corning 184 B and the solution of Dow Corning 184 A in a clean beaker at a mass ratio of 1:(10-20) and stirring with a glass rod for 3-5 min; a 25 mm x 25 mm glass sheet cleaned according to step 2-1) is fixed on the rotating disc of a spin coater, and the PDMS solution is applied thereon and spun at a speed of 500-1000 r / min for 10-20 s; the glass sheet coated with the PDMS solution is placed in a vacuum filter to remove air bubbles in the film, and then placed on a constant temperature heating table to heat and cure the PDMS solution at 80-100°C for 1-2 h, and then removed and cooled to room temperature to obtain a glass sheet coated with a PDMS film; a 15-20 μm thick copper foil is fixed on the PDMS film using a plastic spatula, and placed under the 10 light-emitting mirrors of a nanosecond laser, and cut according to a pre-designed profile at a moving speed of 200-400 mm / min, a power of 3-5 W, a pulse width of 1000 ns and a frequency of 50000 Hz, and the residual copper foil is removed using a sharp-tipped forceps to obtain a copper wire, as shown in Figure 4 Steps a-c; the vibrator 11 is a brushless vibration motor with a diameter of 5-7 mm and a thickness of 2 mm, which is connected to the copper wire, and whether the vibrator 11 is in communication is checked, and after confirming that all vibrators 11 can be normally used, the PDMS solution is again spin-coated according to the spin-coating conditions of the present step; the haptic stimulation reinforcement structure part 12 made by 3D additive technology is embedded in the PDMS solution and corresponds to the vibrator 11 one by one, and the PDMS solution is cured according to the PDMS heating conditions of the present step, as shown in Figure 4 Steps d-f; the whole device is slowly peeled off from the glass sheet using a round-tipped forceps to obtain a haptic feedback actuator.

[0094] Step 7, connection of feedback control circuit

[0095] A sensor capacitor collection, processing and control circuit is designed; the output end of the off-electric type flexible haptic sensor capacitor is connected to the capacitor collection end of the circuit, and the positive and negative electrodes of the vibrator of the haptic feedback actuator are connected to the voltage output end and the GND end of the circuit, respectively, so that a flexible haptic sensing system is obtained.

[0096] Step 2, connection of feedback control circuit

[0097] As Figure 6As shown, the feedback control circuit of the present application includes a capacitor collection module, an ESP32 single-chip microcomputer, an L298N motor drive module, a power module, and an LM2596 voltage reduction module. The capacitor collection module is directly connected to the off-electric flexible tactile sensor 1 and transmits data to the ESP32 single-chip microcomputer through the IIC communication protocol, and delivers the detected different texture characteristic signals to the ESP32 single-chip microcomputer for processing. The power module provides a 5V power supply for the L298N motor drive module, and the L298N motor drive module can also provide power for the ESP32 single-chip microcomputer after obtaining the power supply. Considering that the vibrator 7 in the tactile feedback actuator 2 has a rated voltage of 3.3V, the feedback control circuit of the present application is specially designed with an LM2596 voltage reduction module to reduce the 5V voltage of the L298N motor drive module to 3.3V, ensuring that the vibrator 7 receives appropriate voltage for power supply. Through this design, the feedback control circuit not only efficiently processes signals from the off-electric flexible tactile sensor 1, but also ensures that the tactile feedback actuator 2 receives stable power supply, thereby realizing precise tactile feedback control.

[0098] Example 1

[0099] The present application provides a flexible tactile sensing and feedback system based on texture recognition, and the preparation steps are as follows:

[0100] The TPU particles are mixed in the DMF solution at a mass ratio of 4:10, stirred at 1200r / min for 3h at 120℃, so that the particles are completely dissolved, and a TPU solution is obtained.

[0101] Step 1, tactile interaction film preparation:

[0102] The inverted membrane plate structure is designed, the micro-cone groove structure inverted membrane plate is manufactured by printing technology, the prepared inverted membrane plate is ultrasonically cleaned with isopropanol solution, and after air drying, it is cured with 25W power ultraviolet light for 25min. Pour the TPU solution on the cured inverted membrane plate, remove the bubbles, and then place it on a constant temperature heating table for constant temperature curing at 80℃ for 60min. After the TPU is cooled to room temperature, use a plastic tweezers to peel off the TPU film, and get a tactile interaction film with a micro-cone convex structure.

[0103] Step 2, TPU film electrode preparation:

[0104] The PTFE film glue is evenly adhered to the cleaned glass sheet; the nanosecond laser power is adjusted to 3W, the moving speed is 200mm / min, the pulse width is 1000ns, the frequency is 50000Hz, and the electrode sputtering mask plate is obtained by cutting 4 times; after the mask plate is adhered, it is placed in the vacuum chamber of the magnetron sputtering machine, the Au target material is replaced, the current is adjusted to 30mA, the vacuum pump is started to remove air, and when the pressure in the vacuum chamber is lowered to 3Pa, sputtering is performed for 200s to obtain the electrode pattern; the glass sheet with the sputtered Au electrode PTFE film glue is fixed on the rotating disc of the glue spreading machine, and the TPU solution is spin-coated at a rotating speed of 700r / min for 15s; the TPU film is cured on the constant temperature heating table at 80°C for 60min; the cured film is peeled off to obtain the TPU film electrode.

[0105] Step 3, ion film preparation:

[0106] The 7mL DMF solution is transferred to a beaker with a syringe, 2g of TPU powder and 1.2g of ILs are added in sequence, and the mixture is magnetically stirred at a speed of 1000r / min and a temperature of 100°C for 4h; a piece of 5000 mesh sandpaper is attached to a 60mm×60mm glass sheet using double-sided tape, and the excess sandpaper edges are trimmed; the cooled TPU solution is coated on the sandpaper, which is placed on a constant temperature heating table and heated at a constant temperature of 70°C for 4h to solidify; the TPU ion film is slowly peeled off from the edge to the center of the sandpaper with tweezers.

[0107] Step 4, spacer layer preparation:

[0108] A piece of cleaned 60mm×60mm glass sheet is spin-coated with TPU solution at a speed of 3500r / min for 10s, then heated on a constant temperature heating table at 80°C for 60min, and the TPU film is slowly peeled off from the glass sheet with tweezers to obtain the TPU spacer layer film.

[0109] Step 5, off-electric type flexible tactile sensor packaging:

[0110] A preparation, ultrasonic cleaning and curing hot press mold are prepared; according to the pre-designed profile, the TPU tactile interaction film, the TPU film with sputtered electrodes, the TPU ion film and the TPU spacer layer film are etched in the nanosecond laser in sequence, the laser moving speed is 100mm / min, the tactile interaction film, the TPU film with electrodes and the TPU ion film are cut 15 times in a cycle, the spacer layer film is cut 5 times in a cycle, and the tactile interaction film, the TPU film electrode, the ion film with a diameter of 6mm and the net-like spacer layer are obtained by laser etching; each layer is placed in the hot press mold in sequence under the conditions of 15N pressure and 65°C constant temperature for 10min to complete the packaging of the off-electric type flexible tactile sensor.

[0111] Step 6, preparation of tactile feedback actuator

[0112] The solution of Dow Corning 184 B was mixed with the solution of Dow Corning 184 A at a mass ratio of 1:20, and stirred for 3 min to ensure uniform mixing, to obtain a PDMS solution. A glass piece with a size of 25 mm x 25 mm was washed with anhydrous ethanol, wiped and air-dried; the glass piece was fixed on the rotating disc of a spin coater, the PDMS solution was evenly applied, and spin coating was performed at a speed of 500 r / min for 20 s. The glass piece coated with the PDMS solution was placed in a vacuum filtration machine to remove air bubbles in the film. After the air bubbles were completely removed, the glass piece was placed on a constant temperature heating table, and the PDMS solution was heated and cured at 90℃ for 1.5 h. After cooling to room temperature, a glass piece covered with a PDMS film was obtained. Then, a 15 μm thick copper foil was fixed on the PDMS film using a paper spatula, and placed under the light-emitting mirror of a nanosecond laser. The laser head moved at a speed of 300 mm / min, a power of 3 W, a pulse width of 1000 ns and a frequency of 50000 Hz, and was cut according to a pre-designed pattern for 20 cycles. After cutting, the remaining copper foil was removed using tweezers, and a patterned copper wire was obtained. A brushless vibration motor with a diameter of 6 mm and a thickness of 2 mm was selected as the vibrator, and was connected to the copper wire by welding. After welding, it was checked whether the vibrator was connected, and it was confirmed that all the vibrators worked normally. The PDMS solution was spin coated again according to the above PDMS spin coating conditions. The tactile stimulation reinforcement structure part made by 3D printing technology was embedded in the PDMS solution, and its position was ensured to correspond to the vibrator. The PDMS solution was cured according to the above PDMS heating conditions. Finally, after the PDMS solution was completely cured, the assembled device was peeled off from the glass piece using tweezers, to obtain a tactile feedback actuator.

[0113] Step 7, connection of feedback control circuit

[0114] A sensor capacitance collection, processing and feedback control circuit was designed; the output end of the capacitive flexible tactile sensor was connected to the input end of the capacitance collection module of the circuit, and the positive and negative electrodes of the vibrator of the tactile feedback actuator were connected to the voltage output end of the voltage reduction module of the circuit, to form a flexible tactile sensing and feedback system.

[0115] Example 2

[0116] The present application provides a flexible tactile sensing and feedback system based on texture recognition, and the preparation steps are specifically as follows:

[0117] The TPU particles were mixed in the DMF solution at a mass ratio of 2:10, and were completely dissolved by stirring at 100℃ and 1500 r / min for 2 h, to obtain a TPU solution.

[0118] Step 1, preparation of tactile interaction film:

[0119] The micro-cone groove structure of the reverse film plate is manufactured by printing technology; the manufactured reverse film plate is treated by ultrasonic cleaning with isopropyl alcohol solution; after air drying, it is cured by 30W power ultraviolet light for 20min; TPU solution is poured on the cured reverse film plate, and bubble removal treatment is performed, and then it is placed on a constant temperature heating table for constant temperature curing at 90℃ for 45min; after the TPU is cured and cooled to room temperature, the TPU film is peeled off using a plastic tweezers, and a haptic interaction film with a micro-cone convex structure is obtained.

[0120] Step 2, TPU film electrode preparation:

[0121] The PTFE film glue is evenly adhered to the cleaned glass sheet; the power of the nanosecond laser is adjusted to 4W, the moving speed is 300mm / min, the pulse width is 1000ns, the frequency is 50000Hz, and the electrode sputtering mask plate is obtained by circular cutting for 3 times; after the mask plate is adhered, it is placed in the vacuum chamber of the magnetron sputtering machine, the Au target material is replaced, the current is adjusted to 25mA, the vacuum pump is started to remove air, and when the pressure in the vacuum chamber is lowered to 3Pa, the electrode pattern can be obtained by sputtering for 300s; the glass sheet with the Au electrode sputtered PTFE film glue is fixed on the turntable of the spin coater, and the TPU solution is spin coated at a speed of 500r / min for 20s; the TPU film is cured by heating at 90℃ for 80min on a constant temperature heating table; the cured film is peeled off to obtain a TPU film electrode.

[0122] Step 3, ion film preparation:

[0123] 10mL of DMF solution is transferred to a beaker using a syringe, 2g of TPU powder and 1.5g of ILs are added in sequence, and the mixture is magnetically stirred at a speed of 1500r / min and a temperature of 110℃ for 3h; a piece of 3000 mesh sandpaper is attached to a 60mm×60mm glass sheet using double-sided tape, and the excess sandpaper edges are trimmed; the cooled TPU solution is coated on the sandpaper, and the sandpaper is placed on a constant temperature heating table and heated at a constant temperature of 80℃ for 3h to cure; the TPU ion film is slowly peeled off from the edge to the center of the sandpaper using tweezers.

[0124] Step 4, spacer layer preparation:

[0125] A piece of cleaned 60mm×60mm glass sheet is spin coated with TPU solution at a speed of 3000r / min for 15s, and then heated on a constant temperature heating table at 90℃ for 80min until the TPU film is cured; the TPU spacer layer film is slowly peeled off from the glass sheet using tweezers.

[0126] Step 5, packaging of ion-electric type flexible tactile sensor:

[0127] Preparation, ultrasonic cleaning and curing of the hot-pressing mold; according to the pre-designed profile, the TPU haptic interaction film, the TPU film of the sputtered electrode, the TPU ion film and the TPU spacer layer film are etched in the nanosecond laser in turn, the laser moving speed is 300 mm / min, the haptic interaction film, the electrode TPU film and the TPU ion film are cyclically cut 20 times, the spacer layer film is cyclically cut 8 times, and the laser etching obtains the haptic interaction film, the TPU film electrode, the ion film with a diameter of 8 mm and the reticular spacer layer; each layer is placed in the hot-pressing mold under the condition of 10N pressure and 70℃ constant temperature for 5 min in turn, and the packaging of the electroded flexible tactile sensor is completed.

[0128] Step 6, design and preparation of haptic feedback actuator

[0129] The solution of Dow Corning 184 B is mixed with the solution of Dow Corning 184 A at a mass ratio of 1:10, and stirred with a glass rod for 5 min to obtain a PDMS solution. A 25mm×25mm glass sheet cleaned and wiped with anhydrous ethanol and deionized water respectively and air-dried is fixed on the rotating disc of a spin coater, the PDMS solution is applied, and spin coating is performed at a rotating speed of 700r / min for 15s, then the glass sheet coated with the PDMS solution is placed in a vacuum filter to eliminate air bubbles in the film, and after the air bubbles are removed, the PDMS solution is heated and cured on a constant temperature heating table at 100℃ for 1h, and the glass sheet coated with the PDMS film is obtained after cooling to room temperature; a 20μm thick copper foil is fixed on the PDMS film using a paper spatula, and placed under the light-emitting mirror of a nanosecond laser, and the laser head is cyclically cut 25 times according to the pre-designed profile at a moving speed of 200mm / min, a power of 5W, a pulse width of 1000ns and a frequency of 50000Hz, and then the residual copper foil is taken out using tweezers to prepare an electrical copper wire. In the present application, the vibrator is a brushless vibration motor with a diameter of 5mm and a thickness of 2mm, which is connected to the electrical copper wire by welding, and after the welding is completed, it is checked whether the vibrator is connected. After confirming that all the vibrators can be used normally, the PDMS solution is spin-coated again according to the previously described PDMS spin-coating conditions. Subsequently, the haptic stimulation reinforcement structure is precisely embedded in the PDMS solution, and its position is ensured to correspond to the vibrator. Then, the spin-coated PDMS solution is cured according to the established PDMS solution heating and curing conditions. After the curing is completed, the entire device is peeled off from the glass sheet using tweezers to obtain the haptic feedback actuator.

[0130] Step 7, connection of feedback control circuit

[0131] The sensor capacitor collection, processing and feedback control circuit is designed; the output end of the capacitive flexible tactile sensor is connected to the input end of the capacitor collection module of the circuit, and the positive and negative leads of the vibrator of the tactile feedback actuator are connected to the voltage output end of the voltage reduction module of the circuit respectively, so that a flexible tactile sensing and feedback system is formed.

[0132] Embodiment 3

[0133] The application provides a flexible tactile sensing and feedback system based on texture recognition, and the preparation steps are as follows:

[0134] TPU particles are mixed in a DMF solution at a mass ratio of 3:10, and the particles are completely dissolved by stirring at 1000 r / min for 4 h at 110 DEG C to obtain a TPU solution.

[0135] Step 1, tactile interaction film preparation:

[0136] The film reversing plate structure is designed, the micro-cone groove structure film reversing plate is manufactured by printing technology, the manufactured film reversing plate is cleaned by ultrasonic cleaning with isopropyl alcohol solution, and after air drying, the film reversing plate is cured by ultraviolet light with a power of 20 W for 30 min; the TPU solution is poured on the cured film reversing plate, bubble removal treatment is performed, and then the TPU solution is placed on a constant temperature heating table for constant temperature curing at 70 DEG C for 75 min; after the TPU is cooled to room temperature, the TPU film is peeled off using a plastic tweezers, and a tactile interaction film with a micro-cone convex structure is obtained.

[0137] Step 2, TPU film electrode preparation:

[0138] The PTFE film glue is evenly adhered to the cleaned glass sheet; the power of the nanosecond laser is adjusted to 5 W, the moving speed is 400 mm / min, the pulse width is 1000 ns, the frequency is 50000 Hz, and the electrode sputtering mask plate is obtained by cutting 5 times; after the mask plate is adhered, the glass sheet with the PTFE film glue is placed in the vacuum chamber of the magnetron sputtering machine, the Au target material is replaced, the current is adjusted to 20 mA, the vacuum pump is started to remove air, and when the pressure in the vacuum chamber is lowered to 3 Pa, the electrode pattern is obtained by sputtering for 250 s; the glass sheet with the Au electrode sputtered PTFE film glue is fixed on the turntable of the spin coater, the TPU solution is spin coated at a rotation speed of 1000 r / min for 10 s, and the TPU film is cured by heating at 70 DEG C for 100 min; the cured film is peeled off to obtain a TPU film electrode.

[0139] Step 3, ion film preparation:

[0140] 5 mL DMF solution was transferred to a beaker with a syringe, 2 g of TPU powder and 1 g of ILs were added in turn, and the mixture was stirred at 1200 r / min and 120°C for 2 h. A piece of 1000-mesh sandpaper was attached to a 60 mm x 60 mm glass sheet using double-sided tape, and the excess edges were trimmed. The cooled TPU solution was coated on the sandpaper and placed on a constant temperature heating platform at 60°C for 5 h to solidify. The TPU ion film was slowly peeled off from the edge to the center of the sandpaper with tweezers.

[0141] Step 4, spacer layer preparation:

[0142] A piece of cleaned 60 mm x 60 mm glass was spin-coated with TPU solution at 2500 r / min for 20 s, then heated on a constant temperature heating platform at 70°C for 100 min. The TPU spacer film was slowly peeled off from the glass with tweezers after solidification.

[0143] Step 5, packaging of the off-electric flexible tactile sensor:

[0144] The mold was prepared, ultrasonically cleaned, and cured. The TPU tactile interaction film, sputtered electrode TPU film, TPU ion film, and TPU spacer film were sequentially etched in a nanosecond laser according to the pre-designed profile. The laser moved at a speed of 500 mm / min. The tactile interaction film, electrode TPU film, and TPU ion film were cut 25 times in a cycle, and the spacer film was cut 10 times in a cycle. The laser etching obtained a tactile interaction film, TPU film electrode, ion film with a diameter of 4 mm, and a mesh spacer. Each layer was placed in the hot press mold under a pressure of 20 N and a constant temperature of 60°C for 15 min to complete the packaging of the off-electric flexible tactile sensor.

[0145] Step 6, preparation of tactile feedback actuator

[0146] The solution of Dow Corning 184 B is mixed with the solution of Dow Corning 184 A at a mass ratio of 1:15, and stirred for 4 min to ensure uniform mixing, to obtain a PDMS solution. A glass piece with a size of 25 mm x 25 mm is washed with anhydrous ethanol, wiped and air-dried; the glass piece is fixed on the rotating disc of a spin coater, the PDMS solution is evenly applied, and spin coating is performed at a speed of 1000 r / min for 20 s. The glass piece coated with the PDMS solution is placed in a vacuum filter to remove air bubbles in the film. After the air bubbles are completely removed, the glass piece is placed on a constant temperature heating table, and the PDMS solution is heated and cured at 80℃ for 2 h. After cooling to room temperature, a glass piece covered with a PDMS film is obtained. Then, a 18 μm thick copper foil is fixed on the PDMS film using a paper spatula, and placed under the light-emitting mirror of a nanosecond laser. The laser head moves at a speed of 400 mm / min, a power of 4 W, a pulse width of 1000 ns and a frequency of 50000 Hz, and cuts according to a pre-designed pattern for 15 cycles. After cutting, the remaining copper foil is removed using tweezers, and a patterned copper wire is obtained. A brushless vibration motor with a diameter of 7 mm and a thickness of 2 mm is selected as a vibrator, and is connected to the copper wire by welding. After welding, it is checked whether the vibrator is connected, and it is confirmed that all the vibrators work normally. The PDMS solution is spin coated again according to the above PDMS spin coating conditions. A haptic stimulation reinforcing structure made by using a 3D printing technology is embedded in the PDMS solution, and it is ensured that the position corresponds to the vibrator. The PDMS solution is cured according to the above PDMS heating conditions. Finally, after the PDMS solution is completely cured, the assembled device is peeled off from the glass piece using tweezers, to obtain a haptic feedback actuator.

[0147] Step 7, connection of feedback control circuit

[0148] A sensor capacitor acquisition, processing and feedback control circuit is designed; the output end of the off-electric type flexible tactile sensor capacitor is connected to the input end of the capacitor acquisition module of the circuit, and the positive and negative electrode wires of the vibrator of the haptic feedback actuator are connected to the voltage output end of the voltage reduction module of the circuit, to form a flexible tactile sensing and feedback system.

[0149] In one embodiment of the present application, a design method of a flexible tactile sensing and feedback system based on texture recognition is provided. The system comprises a 25 mm x 25 mm haptic feedback actuator, a corresponding feedback control circuit and an off-electric type flexible tactile sensor connected thereto.

[0150] The working process of the system is as follows: the off-electric flexible tactile sensor captures characteristic capacitive signals when contacting different texture surfaces. The signals are collected by the capacitive collection module and transmitted to the ESP32 single-chip microcomputer through the IIC communication protocol. The ESP32 single-chip microcomputer analyzes the signals, extracts characteristic information such as capacitive frequency and peak value, and converts them into digital signals. Subsequently, the single-chip microcomputer outputs the corresponding duty ratio PWM signal to the L298N motor drive module at the IOA port, and the module adjusts the voltage according to the PWM signal to control the tactile feedback actuator to generate vibrations of different intensities, simulating the tactile sensation of different textures.

[0151] In summary, the present application provides a flexible tactile sensing and feedback system and method based on texture recognition, including an off-electric flexible tactile sensor, a feedback actuator and a tactile feedback control circuit. The off-electric flexible tactile sensor includes a tactile interaction film for obtaining texture characteristics and a pressure sensor for converting texture characteristics; the feedback actuator completes the tactile feedback of the texture characteristic signals obtained by the flexible sensor in the form of vibration; the tactile control system is mainly connected to the off-electric flexible tactile sensor and the tactile feedback actuator through the feedback control circuit; the tactile feedback actuator has a stimulating reinforcement structure on the contact surface with the human body, which can further enhance the fine feedback of the tactile sensation. The present application can effectively identify texture characteristics and complete fine tactile feedback in the form of vibration, providing effective assistance for the tactile recovery of disabled people, and has important application value in the game industry, especially in the development of virtual reality (VR) technology.

[0152] The present application is not limited to the above-mentioned embodiments, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed in the present application, which should be covered within the protection scope of the present application.

Claims

1. A flexible tactile sensing and feedback system based on texture recognition, characterized by, It includes an ionized flexible tactile sensor (1), a tactile feedback actuator (2), and a feedback control circuit (3). The feedback control circuit (3) is used to convert the capacitive signals of different texture features collected by the ionized flexible tactile sensor (1) into signals of different mechanical vibrations of the tactile feedback actuator (2) to realize tactile feedback. The ionized flexible tactile sensor (1) includes an ion membrane (5) disposed between a bottom TPU membrane electrode (4) and a top TPU membrane electrode (7). The hierarchical micron-scale structure on the surface of the ion membrane (5) is disposed towards the top TPU membrane electrode (7). A mesh spacer layer (6) is disposed between the ion membrane (5) and the top TPU membrane electrode (7). A tactile interaction membrane (8) is connected to the top TPU membrane electrode (7). The tactile interaction membrane (8) has a micro-conical protrusion structure. When in use, the micro-conical protrusion structure contacts and rubs against the object to be textured. The tactile feedback actuator (2) includes a PDMS film with a tactile stimulation enhancement structure component (12) embedded in it, a vibrator (11), a copper wire (9) and a PDMS substrate film (13) connected from top to bottom. The tactile stimulation enhancement structure component (12) has a micron-level protrusion structure, which comes into contact with human skin during use. The specific steps for preparing the ionized flexible tactile sensor (1) are as follows: 1) TPU solution preparation: TPU particles are mixed with DMF solution to obtain TPU solution; 2) Fabrication of tactile interaction membrane: TPU solution is poured onto a mold plate with a microconical groove structure and cured to obtain a TPU film with a microconical protrusion structure. The TPU film is then dimensionally etched according to a set shape to obtain a tactile interactive film. 3) TPU film electrode fabrication: A photomask is fixed on the PTFE film adhesive surface, electrodes are sputtered, and TPU solution is spin-coated onto the PTFE film adhesive surface with sputtered electrode patterns. After curing, a TPU film with electrodes is obtained. The TPU film is etched according to the set shape to obtain the TPU film electrode. 4) Preparation of ion exchange membranes: TPU, DMF solution and ILs are heated and mixed to obtain TPU ionic solution. TPU ionic solution is coated on sandpaper and cured to obtain TPU ionic film with hierarchical micron-scale structure. TPU ionic film is etched according to the set shape to obtain TPU ionic film. 5) Spacer layer preparation: TPU solution is spin-coated onto a glass slide and cured to obtain a TPU film. The TPU film is then etched according to a set shape to obtain a mesh spacer layer. 6) Packaging of ionized flexible tactile sensors: The bottom TPU membrane electrode (4), ion membrane (5), mesh spacer layer (6), top TPU membrane electrode (7), and tactile interaction membrane (8) are placed from bottom to top and then hot-pressed to obtain an ionized flexible tactile sensor. In step 1), the mass ratio of TPU to DMF solution is (2~4):10, and the mixture is heated and stirred at a speed of 1000r / min~1500r / min and a temperature of 100℃~120℃ for 2h~4h. In step 2), the molded substrate is cured under UV light at a power of 20W~30W for 20min~30min, and the TPU film is cured at a temperature of 70℃~90℃ for 45min~75min; In step 3), an A4 paper is used to prepare a photomask. Specifically, the A4 paper is laser-cut 3 to 5 times under the conditions of 3W~5W power and 200mm / s~400mm / s moving speed. When sputtering the electrode: sputter with a current of 20mA~30mA for 200s~300s, with Au as the target material; The TPU solution was spin-coated at a speed of 500r / min to 1000r / min for 10s to 20s and then cured at a temperature of 70℃ to 90℃ for 60min to 100min. In step 4), TPU, DMF solution and ILs are mixed in a ratio of 2g:(5~10)mL:(1~1.5)g and stirred for 2h~4h at a temperature of 100℃~120℃ and a speed of 1000r / min~1500r / min to obtain TPU ionic solution. TPU ionic solution is coated onto sandpaper and cured at 60℃~80℃ for 3h~5h to obtain TPU ionic film; In step 5), the TPU solution is spin-coated at a speed of 2500r / min~3500r / min for 10s~20s and cured at a temperature of 70℃~90℃ for 60min~100min to obtain the spacer layer; In step 6), when performing thermo-press sealing, the pressure is 10N~20N, the temperature is 60℃~70℃, and the time is 5min~15min.

2. The flexible tactile sensing and feedback system based on texture recognition according to claim 1, wherein, The tactile interaction membrane (8) is a TPU film with a micro-conical protrusion structure; the bottom TPU membrane electrode (4) and the top TPU membrane electrode (7) are both integrated structures of TPU film and Au electrode. A TPU solution with a thickness of 8μm~10μm is scraped on the non-electrode surface of the top TPU membrane electrode (7), and a TPU solution with a thickness of 8μm~10μm is scraped on the periphery of the non-electrode area of ​​the electrode surface of the bottom TPU membrane electrode (4).

3. The flexible tactile sensing and feedback system based on texture recognition according to claim 1, wherein, The specific steps for preparing the tactile feedback actuator (2) are as follows: 1) Spin-coating the PDMS solution onto the substrate and curing it to obtain a PDMS film; 2) Copper foil is adsorbed onto the surface of a PDMS film, and copper wires are obtained by etching; 3) Connect the vibrator and the copper wire, check for continuity, and then spin-coat with PDMS solution; 4) Embed the tactile stimulation enhancement structure components in the PDMS solution, corresponding one-to-one with the vibrator, and obtain the tactile feedback actuator after heating and curing.

4. The flexible tactile sensing and feedback system based on texture recognition according to claim 3, wherein, In step 1), the PDMS solution is prepared by mixing Dow Corning 184 B and A solutions at a mass ratio of 1:(10~20); the PDMS solution is spin-coated on the substrate at a speed of 500r / min~1000r / min for 10s~20s, and cured at a temperature of 80℃~100℃ for 1h~2h to obtain a PDMS film. In step 2), a nanosecond laser is used for etching with a power of 3W~5W, a pulse width of 1000ns, a frequency of 50000Hz, a speed of 200mm / s~400mm / s, and 15~25 cutting cycles.

5. The flexible tactile sensing and feedback system based on texture recognition according to claim 1, wherein, The vibrator (11) is a brushless vibrating motor with a diameter of 5mm~7mm and a thickness of 2mm.

6. The flexible tactile sensing and feedback system based on texture recognition according to claim 1, characterized in that, The feedback control circuit includes a capacitance acquisition module, an ESP32 microcontroller, a motor drive module, a power supply module, and a step-down module. The capacitance acquisition module is used to collect the capacitance signal output by the ionized flexible tactile sensor (1) and transmit it to the ESP32 microcontroller. The ESP32 microcontroller is used to convert capacitor signals into the output voltage for controlling the motor drive module. The power module is used to supply power to the motor drive module; The motor drive module receives voltage change data output by the ESP32 main control microcontroller and transmits it to the buck module, which reduces the voltage to the operating voltage of the haptic feedback actuator. The change in the output voltage of the motor drive module is controlled by the ESP32 main control microcontroller. The output voltage is transmitted to the step-down module, which reduces the voltage to the working voltage of the haptic feedback actuator (2).

7. A flexible tactile sensing and feedback system based on texture recognition according to claim 6, characterized in that, The capacitance acquisition module transmits data with the ESP32 main control microcontroller via the IIC communication protocol. The ESP32 microcontroller is used to collect the capacitor frequency and peak value from the capacitor module, process them, and output a PWM square wave at the IOA port to control the output voltage of the motor drive module.

8. A texture recognition method using the system described in any one of claims 1 to 7, characterized in that, The specific steps are as follows: 1) Connect the deionized flexible tactile sensor (1) to the tactile feedback actuator (2) through the feedback control circuit (3); 2) The protruding structure of the tactile interaction membrane (8) of the ionized flexible tactile sensor (1) is brought into contact with the object to be textured and rubbed to obtain a capacitance signal. The ionized flexible tactile sensor (1) transmits the capacitance signal to the feedback control circuit (3). 3) The feedback control circuit (3) converts the capacitor signal into the vibration signal of the tactile feedback actuator (2) and transmits it to the tactile feedback actuator (2). 4) The vibrator (11) of the tactile feedback actuator (2) vibrates according to the received vibration signal. The micron-level protrusions on the tactile stimulation enhancement structure component (12) vibrate under the drive of the vibrator (11), and the tactile sensation of the object to be textured is fed back to the human skin through vibration.

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