A Flexible Piezoresistive Sensor, Smart Glove and UAV Gesture Control Method

Abstract

The present invention discloses a flexible piezoresistive sensor, an intelligent glove and a method for controlling a drone by gestures, which relates to the technical field of drone control. A flexible piezoresistive sensor includes a microcone polydimethylsiloxane film layer, a composite film layer and a polydimethylsiloxane film layer stacked in sequence from bottom to top; the composite film layer includes a thermoplastic polyurethane elastomer fiber film and a microcracked multi-walled carbon nanotube film, the thermoplastic polyurethane elastomer fiber film is attached to the microcone polydimethylsiloxane film layer, and the microcracked multi-walled carbon nanotube film is attached to the polydimethylsiloxane film layer; conductive electrode materials are attached to both ends of the microcracked multi-walled carbon nanotube film. The flexible piezoresistive sensor of the present invention can quickly change its resistance value under the action of force, so as to achieve fast response and high-sensitivity pressure detection, has high sensitivity and accuracy, and can be applied to an intelligent glove using the method for controlling a drone by gestures to precisely control the drone.

Description

Technical Field

[0001] The present invention relates to the technical field of UAV control, and particularly to a flexible piezoresistive sensor, an intelligent glove and a UAV gesture control method. Background Art

[0002] Consumer-grade UAVs require simple and convenient operation, and the market demand for consumer-grade UAVs is increasing. However, the operation of most UAVs still relies on a remote controller or is controlled through an application on a smart device, with complex operation, inconvenient control, and high professional requirements for operators. For the general public, there is a certain learning cost, which is not conducive to the popularization of UAVs.

[0003] Although gesture control has emerged in current UAV operation, most of them adopt pattern recognition or image recognition gestures. Image recognition requires a camera module, a sensor and an image processing chip with a certain clarity, resulting in high costs; at a long distance, the accuracy of image recognition gestures is not high, and misoperation is likely to occur; in emergency situations or complex environments (such as low light, foggy weather, etc.), it is difficult to quickly or accurately respond to the operator's instructions, with great limitations and unable to perfectly meet the needs of UAV control.

[0004] Existing UAV operation mainly adopts pattern recognition or image recognition gestures, and the sensors used have poor recognition effects at long distances or in complex environments, making it difficult to control UAVs sensitively and precisely; therefore, the existing UAVs have the problems that the control method cannot control UAVs sensitively and precisely and has great limitations. Summary of the Invention

[0005] In view of the above deficiencies of the prior art, the purpose of the present application is to provide a flexible piezoresistive sensor, an intelligent glove and a UAV gesture control method, aiming to solve the problems that the existing UAVs have great limitations in that the control method cannot control UAVs sensitively and precisely.

[0006] To solve the above technical problems, the purpose of the present invention is achieved through the following technical solutions:

[0007] On the one hand, the present invention discloses a flexible piezoresistive sensor, which includes a microconical polydimethylsiloxane film layer, a composite film layer, and a polydimethylsiloxane film layer stacked in sequence from bottom to top; wherein, the composite film layer includes a thermoplastic polyurethane elastomer fiber film and a microcracked multi-walled carbon nanotube film, the thermoplastic polyurethane elastomer fiber film is attached to the microconical polydimethylsiloxane film layer, and the microcracked multi-walled carbon nanotube film is attached to the polydimethylsiloxane film layer; conductive electrode materials are attached to both ends of the microcracked multi-walled carbon nanotube film; the thickness of the microcracked multi-walled carbon nanotube film is 1-10 μm; the preparation steps of the composite film layer include: coating an aqueous dispersion of multi-walled carbon nanotubes on the thermoplastic polyurethane elastomer fiber film, drying and then stretching and rebounding to obtain the composite film layer with the microcracked multi-walled carbon nanotube film; the preparation steps of the microconical polydimethylsiloxane film layer include: mixing polydimethylsiloxane matrix and a curing agent evenly, pouring them into a mold with a microconical structure and curing, and then taking out to obtain the microconical polydimethylsiloxane film layer; the thickness of the microconical polydimethylsiloxane film layer is 0.2-1 mm.

[0008] Optionally, the thickness ratio of the microconical polydimethylsiloxane film layer, the microcracked multi-walled carbon nanotube film, the thermoplastic polyurethane elastomer fiber film, and the polydimethylsiloxane film layer is: (200-1000):(1-10):(50-200):(200-1000).

[0009] Optionally, the preparation steps of the thermoplastic polyurethane elastomer fiber film include: dissolving the thermoplastic polyurethane elastomer in an organic mixed solvent to obtain a thermoplastic polyurethane elastomer solution, and performing electrospinning treatment on the thermoplastic polyurethane elastomer solution to obtain the thermoplastic polyurethane elastomer fiber film; the organic mixed solution is selected from at least one of a mixture of dimethylformamide and ethyl acetate and a mixture of dimethylformamide and tetrahydrofuran; in the thermoplastic polyurethane elastomer solution, the mass fraction of the thermoplastic polyurethane elastomer is 18-25 wt%; the parameters of the electrospinning treatment are: voltage 14-16 kV, distance between the needle and the collector 12-18 cm, and the flow rate of the thermoplastic polyurethane elastomer solution is 1-4 mL / h.

[0010] Optionally, in the preparation steps of the composite film layer, the aqueous dispersion of multi-walled carbon nanotubes contains multi-walled carbon nanotubes and a dispersant, the mass fraction of the multi-walled carbon nanotubes is 8-12 wt%, and the mass fraction of the dispersant is 1-4 wt%; the diameter of the multi-walled carbon nanotubes is 10-25 nm, and the length is 5-15 μm; the crack spacing of the microcracked multi-walled carbon nanotube film is 80-120 μm.

[0011] Optionally, in the preparation step of the micro-conical polydimethylsiloxane film layer, the mass ratio of the polydimethylsiloxane matrix to the curing agent is (8 - 12):1.

[0012] Optionally, the flexible piezoresistive sensor further includes a first polyurethane film layer and a second polyurethane film layer. The first polyurethane film layer is disposed below the micro-conical polydimethylsiloxane film layer, and the second polyurethane film layer is disposed above the polydimethylsiloxane film layer. The thickness of the first polyurethane film layer is 50 - 150 μm, and the thickness of the second polyurethane film layer is 50 - 150 μm.

[0013] On the other hand, the present invention discloses an intelligent glove, including a glove body and the flexible piezoresistive sensor as described above. The flexible piezoresistive sensor is attached to the glove body.

[0014] Optionally, the intelligent glove further includes a main control board, which includes a fixed resistor, a single-chip microcomputer, a filter, an operational amplifier, and a wireless communication module. There are four flexible piezoresistive sensors, which are respectively attached to the pulp positions of the fingers except the thumb on the glove body corresponding to the human fingers, for identifying and collecting finger pressure signals. The single-chip microcomputer is connected to the wireless communication module.

[0015] The flexible piezoresistive sensor has a resistance. Each flexible piezoresistive sensor is connected in series with the fixed resistor to form a voltage division circuit, which converts the change in resistance value into a change in voltage division, and then successively passes through the filter and the operational amplifier to form a stable voltage signal and input it into the single-chip microcomputer.

[0016] In addition, the present invention also discloses a method for controlling a drone gesture, including the following steps:

[0017] Step 1: Put on the intelligent glove on the hand, and install a drone instruction execution module on the drone body.

[0018] The intelligent glove is the intelligent glove as described above.

[0019] The drone instruction execution module includes a flight control module and a Raspberry Pi.

[0020] The Raspberry Pi receives the instruction signal and converts it into a control signal for the corresponding flight mode of the drone. At the same time, the Raspberry Pi is connected to the flight control module, and the flight control module controls the drone body to complete various actions.

[0021] Step 2: By setting a threshold value, determine whether the flexible piezoresistive sensor is in a state of heavy press or light pinch.

[0022] Step 3: Combine and input the status information of the flexible piezoresistive sensor into the single-chip microcomputer to obtain the gesture status corresponding to each combined information and the instruction corresponding to the gesture status;

[0023] Step 4: The executor makes corresponding gesture actions with fingers as required, and the single-chip microcomputer transmits the instruction signal to the Raspberry Pi through the wireless communication module;

[0024] Step 5: After receiving the instruction signal, the Raspberry Pi converts the gesture action into a drone control signal, so as to control the drone to complete the instruction action.

[0025] Optionally, the gesture status in Step 3 and the instruction corresponding to the gesture status include:

[0026] Gently pinch the index finger with the thumb, and the drone executes a descending operation;

[0027] Press the index finger hard with the thumb, and the drone executes a landing operation;

[0028] Gently pinch the middle finger with the thumb, and the drone executes a forward movement operation;

[0029] Press the middle finger hard with the thumb, and the drone executes a backward movement operation;

[0030] Gently pinch the ring finger with the thumb, and the drone executes a left flight operation;

[0031] Press the ring finger hard with the thumb, and the drone executes a right flight operation;

[0032] Gently pinch the little finger with the thumb, and the drone executes an ascending operation;

[0033] Press the little finger hard with the thumb, and the drone executes a takeoff operation;

[0034] The pressure for gentle pinching is 5 - 30 kPa, and the pressure for hard pressing is 80 - 200 kPa.

[0035] Beneficial effects:

[0036] In the flexible piezoresistive sensor, intelligent glove and UAV gesture control method of the present invention, the flexible piezoresistive sensor includes a micro-conical polydimethylsiloxane film layer, a composite film layer and a polydimethylsiloxane film layer. The micro-cracked multi-walled carbon nanotube film of the composite film layer has micron-scale cracks that expand under physical pressure, which can increase the number of resistance paths inside the film, resulting in a significant decrease in resistance. Moreover, the micron-scale cracks enable the micro-cracked multi-walled carbon nanotube film to generate obvious electrical signal changes even under a small force, greatly improving the sensitivity and operation response speed of the sensor. The micro-conical polydimethylsiloxane film layer has a micro-conical structure, which can increase the specific surface area of the film by increasing the density and distribution uniformity of the micro-conical structure, improving the sensitivity of the film, and thus more accurately capturing and transmitting tiny pressure changes.

[0037] Therefore, when the flexible piezoresistive sensor is subjected to force, it can quickly change its resistance value, thereby achieving fast response and high-sensitivity pressure detection. It has high sensitivity and accuracy, can accurately capture and transmit tiny pressure changes, and can be applied to an intelligent glove using the UAV gesture control method to sensitively sense the pressure changes brought about by gesture changes, so as to precisely control the UAV. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings below are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0039] Figure 1 is a cross-sectional view of the flexible piezoresistive sensor of the present invention;

[0040] Figure 2 is a schematic diagram of the flexible piezoresistive sensor of the present invention;

[0041] Figure 3 is a finished product diagram of the flexible piezoresistive sensor prepared in Example 1 of the present invention;

[0042] Figure 4 is a schematic diagram of the cyclic electrical signal response of the flexible piezoresistive sensor prepared in Example 1 of the present invention under different pressing degrees;

[0043] Figure 5 is a comparison diagram of stress nephograms of the micro-conical PDMS film layer prepared in Example 1 of the present invention, the micro-pyramidal PDMS film layer prepared in Comparative Example 2, the micro-cylindrical PDMS film layer prepared in Comparative Example 3, and the micro-prismatic PDMS film layer prepared in Comparative Example 4 under different strains;

[0044] Figure 6Comparison chart of strain-pressure test data of the micro-cone PDMS film layer prepared in Example 1 of the present invention, the micro-pyramid PDMS film layer prepared in Comparative Example 2, the micro-cylinder PDMS film layer prepared in Comparative Example 3, and the micro-prism PDMS film layer prepared in Comparative Example 4;

[0045] Figure 7 Finished product diagram of the intelligent glove prepared in Example 1 of the present invention;

[0046] Figure 8 Circuit schematic diagram of the main control board of the intelligent glove prepared in Example 1 of the present invention;

[0047] Figure 9 Schematic diagram of the gesture control method for drones of the present invention.

[0048] Explanation of reference numerals:

[0049] 1. Composite film layer; 11. TPU fiber film; 12. Micro-cracked MWCNTs film; 2. Micro-cone PDMS film layer; 3. PDMS film layer; 4. Electrode material; 5. Second PU film layer; 6. First PU film layer; V in , Power supply voltage; R s , Resistance of the flexible piezoresistive sensor; R1, Fixed resistor; C1, Filter; T1, Operational amplifier; D1, Single-chip microcomputer. Detailed implementation manners

[0050] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0051] It should be understood that when used in this specification and the appended claims, the terms "comprises" and "comprising" indicate the presence of the described features, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0052] A flexible piezoresistive sensor includes a micro-cone polydimethylsiloxane film layer (i.e., micro-cone PDMS film layer), a composite film layer, and a polydimethylsiloxane film layer (i.e., PDMS film layer) stacked in sequence from bottom to top. The composite film layer includes a thermoplastic polyurethane elastomer fiber film (i.e., TPU fiber film) and a micro-cracked multi-walled carbon nanotube film (i.e., micro-cracked MWCNTs film); the thermoplastic polyurethane elastomer fiber film is attached to the micro-cone polydimethylsiloxane film layer, and the micro-cracked multi-walled carbon nanotube film is attached to the polydimethylsiloxane film layer.

[0053] The thickness of each film layer directly affects the microstructure morphology of the flexible piezoresistive sensor. In this application, the thickness of the microcrack MWCNTs film in the composite film layer is preferably 1 - 10 μm, specifically it can be 1 μm, 2 μm, 4 μm, 8 μm, 10 μm; the thickness of the TPU fiber film is preferably 50 - 200 μm, specifically it can be 50 μm, 100 μm, 120 μm, 140 μm, 200 μm. At the same time, the thickness of the microcone PDMS film layer is preferably 0.2 - 1 mm, specifically it can be 0.2 mm, 0.5 mm, 0.8 mm, 1.0 mm; among them, the diameter of the microcone is 100 - 150 um, and the height is 80 - 120 um; the thickness ratio of the microcone PDMS film layer, the microcrack MWCNTs film, the TPU fiber film and the PDMS film layer is preferably any value within (200 - 1000):(1 - 10):(50 - 200):(200 - 1000), specifically it can be: 200:1:50:200, 500:4:100:500, 1000:10:200:1000, 600:6:200:400, 800:10:120:600, 400:8:140:600.

[0054] The microcrack structure of the microcrack MWCNTs film expands under the action of physical pressure, which can increase the number of resistance paths inside the film, thus leading to a significant decrease in resistance; and the micron-level cracks enable the microcrack MWCNTs film to generate obvious electrical signal changes even under a small force, greatly improving the sensitivity and operation response speed of the sensor; the thickness of the microcrack MWCNTs film can affect the number of resistance paths inside the film, thereby affecting its sensitivity and operation response speed under force.

[0055] The preparation steps of the composite film layer include: coating an aqueous dispersion of multi-walled carbon nanotubes on the TPU fiber film, and after drying, obtaining the composite film layer with a microcrack MWCNTs film through stretching and springback. That is, the composite film layer uses the TPU fiber film as the substrate, and a microcrack MWCNTs film is prepared on the surface.

[0056] Among them, the preparation steps of the TPU fiber film include: dissolving the thermoplastic polyurethane elastomer in an organic mixed solvent to obtain a solution of the thermoplastic polyurethane elastomer, and performing electrospinning treatment on the solution of the thermoplastic polyurethane elastomer to obtain the TPU fiber film.

[0057] The organic mixed solution is selected from at least one of a mixed solution of dimethylformamide and ethyl acetate and a mixed solution of dimethylformamide and tetrahydrofuran; preferably, in the mixed solution of dimethylformamide and ethyl acetate, the mass ratio of the two is (1 - 4):1, specifically, it can be 1:1, 2:1, 3:1, 4:1; in the mixed solution of dimethylformamide and tetrahydrofuran, the mass ratio of the two is (0.5 - 2):1, specifically, it can be 0.5:1, 1:1, 2:1.

[0058] In the thermoplastic polyurethane elastomer solution, the mass fraction of the thermoplastic polyurethane elastomer is preferably 18 - 25 wt%.

[0059] The parameters of the electrospinning treatment are preferably: voltage 14 - 16 kV, distance between the needle and the collector 12 - 18 cm, and the flow rate of the thermoplastic polyurethane elastomer solution is 1 - 4 mL / h. The parameters of the electrospinning treatment can interact to affect the formation structure of the fiber membrane. When the voltage is too high, the jet will be unstable, resulting in a wider fiber diameter distribution; when the voltage is too low, it is difficult to overcome the surface tension of the solution, resulting in a larger fiber diameter and difficulty in forming continuous fibers; when the distance between the needle and the collector is too close, the jet cannot be fully dried and stretched; when the distance between the needle and the collector is too far, the fiber yield will be reduced and the cost will be increased; when the flow rate is too fast, the solvent cannot be fully volatilized, causing the fiber diameter to increase and forming bead-like defects; when the flow rate is too slow, the jet will be unstable and an ideal fiber structure cannot be obtained.

[0060] The diameter, length, mass fraction of multi-walled carbon nanotubes and the mass fraction of the dispersant can all affect the crack structure of the prepared film layer. The aqueous dispersion of multi-walled carbon nanotubes contains multi-walled carbon nanotubes and a dispersant. The mass fraction of the multi-walled carbon nanotubes is preferably 8 - 12 wt%, and the mass fraction of the dispersant is preferably 1 - 4 wt%; the diameter of the multi-walled carbon nanotubes is preferably 10 - 25 nm, and the length is preferably 5 - 15 μm; it can ensure that the surface of the obtained film has a micron-scale crack structure; prevent the multi-walled carbon nanotubes from being unevenly dispersed and overly agglomerated, resulting in an uneven film structure and difficulty in forming cracks; it can also prevent the multi-walled carbon nanotubes from being overly dispersed, resulting in a decrease in mechanical properties and difficulty in rebounding after stretching. The crack spacing of the microcrack MWCNTs film is preferably 80 - 120 μm. The dispersant is preferably a polymer-type dispersant, specifically, it can be polyvinylpyrrolidone, polyvinylpyrrolidone, sodium polyacrylate, etc.

[0061] The aqueous dispersion of multi-walled carbon nanotubes is coated on the TPU fiber film, and the coating rate is preferably 2-5 mm / s. Too fast or too slow coating rate will lead to uneven coating. The thermoplastic polyurethane elastomer fiber film coated with the aqueous dispersion of multi-walled carbon nanotubes is dried under the conditions of temperature 25-30°C, humidity 40-50%, and drying in a well-ventilated environment; too high humidity will affect the drying effect, making it difficult to completely dry, prolonging the production cycle, or making the crack structure after stretching unclear; too low humidity is prone to over-drying, causing the film to become hard and brittle, making it difficult to perform subsequent stretching operations.

[0062] Conductive electrode materials are provided at both ends of the microcrack MWCNTs membrane; the conductive electrode materials can be attached before or after stretching, and the conductive electrode materials are used for connection and conduction. The conductive electrode materials can be selected from flexible conductive materials, such as elastic silver paste, nickel-copper conductive fabric, silver fiber fabric, electrode materials containing carbon-based conductive additives, copper foil, etc.

[0063] The purpose of the stretching operation is to destroy the surface structure of the film layer and form a crack structure on its surface; the stretching rate is preferably 1-4mm / s, and the film layer is stretched to 100% strain and then released. The surface area of ​​the film layer changes very little after rebound, but a micron-level crack structure can be formed; the stretching is bidirectional stretching, that is, simultaneous stretching in the transverse and longitudinal directions; the stretching strength and rate should be moderate to prevent unnecessary damage to the film layer.

[0064] The preparation steps of the micro-cone PDMS film layer include: uniformly mixing a polydimethylsiloxane matrix and a curing agent, pouring the mixture into a mold with a micro-cone structure, curing the mold, and then taking out the micro-cone PDMS film layer to obtain the micro-cone PDMS film layer.

[0065] The micro-cone PDMS membrane layer can increase the specific surface area of ​​the membrane by increasing the density and distribution uniformity of the micro-cone structure, thereby improving the sensitivity of the membrane and capturing and transmitting tiny pressure changes more accurately.

[0066] Among them, the mass ratio of the polydimethylsiloxane matrix to the curing agent is (8 - 12):1; this increases the toughness and elasticity of the film layer. The curing agent can be its corresponding curing agent, and options include hydrogen-containing silicone oil, monobutyl phthalate, special curing agent C-100, etc.; preferably, a two-component product of Sylgard 184 can be selected. Sylgard 184 includes a matrix and a curing agent, where the curing agent is vinyl-terminated polydimethylsiloxane (Vinyl-Terminated PDMS). The mold with a microconical structure can be a bionic structure mold. More specifically, the mold with a microconical structure can be selected as the mold obtained by stamping and replicating the paper mulberry leaf. Using a template with a microconical structure to stamp and replicate the leaf can reduce costs, and the paper mulberry leaf also has a microconical structure, which can be used as a mold to prepare a microconical PDMS film layer. The curing parameters are preferably curing for 1 - 4 h in a vacuum environment of 40 - 80°C and 0.5 - 2 bar.

[0067] The mold with a microconical structure can be obtained by pouring a uniformly mixed PDMS (i.e., polydimethylsiloxane) and curing agent above the leaf, followed by curing and demolding; in the mold with a microconical structure, the mass ratio of PDMS to the curing agent is preferably 3 - 6:1 to make it have stronger hardness; and the curing agent can be selected from hydrogen-containing silicone oil, monobutyl phthalate, special curing agent C-100, etc.; the curing parameters are preferably curing for 3 - 6 h in a vacuum environment of 40 - 80°C and 0.5 - 2 bar. In the mold with a microconical structure, to avoid the formation of too strong chemical bonds between the mold and the subsequent coating, a metal nanoparticle film is sprayed on the surface of the mold using a magnetron sputtering device. The metal nanoparticles can be platinum nanoparticles, gold nanoparticles, etc.

[0068] The preparation method of the flexible piezoresistive sensor is to stack the microconical PDMS film layer, the composite film layer, and the PDMS film layer from bottom to top and then encapsulate them with a polyurethane film layer; that is, the flexible piezoresistive sensor preferably further includes a first polyurethane film layer (i.e., the first PU film layer) and a second polyurethane film layer (i.e., the second PU film layer). The first PU film layer is disposed below the microconical PDMS film layer, and the second PU film layer is disposed above the PDMS film layer; the thickness of the first PU film layer is 50 - 150 μm, and the thickness of the second PU film layer is 50 - 150 μm. Both the first PU film layer and the second PU film layer are preferably PU films with high elasticity and medical grade.

[0069] Among them, the PDMS film layer can be an existing commercially available product, or obtained by uniformly mixing and curing a polydimethylsiloxane matrix and a curing agent.

[0070] Refer to the appendix Figure 1 and Figure 2, the flexible piezoresistive sensor can be composed of a microcone PDMS film layer 2, a composite film layer 1, and a PDMS film layer 3 stacked from bottom to top; the composite film layer 1 contains a TPU fiber film 11 and a microcrack MWCNTs film 12, and electrode materials 4 are attached to both ends of the microcrack MWCNTs film 12; specifically, the electrode materials 4 are located between the microcrack MWCNTs film 12 and the PDMS film layer 3, which can prevent the PDMS film layer 3 from damaging the carbon nanotube structure in the microcrack MWCNTs film 12 to a certain extent.

[0071] Meanwhile, a first PU film layer 6 is attached to the lower part of the microcone PDMS film layer 2, and a second PU film layer 5 is attached to the upper part of the PDMS film layer 3 for encapsulation to protect the internal laminated structure.

[0072] The prepared flexible piezoresistive sensor can be applicable to monitoring the pressure range of 0 - 200 kPa, and can exhibit good sensitivity at low, medium, and high pressures. Specifically, the flexible piezoresistive sensor can exhibit -0.14004 kPa -1 , -0.00268 kPa -1 and -0.00149 kPa -1 sensitivity.

[0073] Example 1, a flexible piezoresistive sensor is prepared through the following steps.

[0074] (1) Prepare the TPU fiber film

[0075] The TPU particles (WHT - 1180; TPU thermoplastic elastomer; specific gravity: 1.18 g / cm 3 ) are dried in a vacuum oven at 80 °C for 24 hours to remove the moisture therein. Subsequently, the TPU particles are dissolved in a mixed solvent of dimethylformamide (DMF) and ethyl acetate (EAC) at a concentration of 20 wt%, and the volume ratio of DMF to EAC is 2:1. The dissolution process is carried out at 80 °C and is magnetically stirred for 8 hours to ensure complete dissolution of the particles to obtain a TPU solution.

[0076] Then, using an electrospinning device, the prepared TPU solution is placed in a 10 mL syringe equipped with a 20 - gauge blunt needle, and the flow of the solution is precisely controlled by a digital injection pump. The electrospinning process is carried out in an environment of room temperature and 60% humidity, applying a voltage of 15 kV, the distance between the needle and the collector is maintained at 15 cm, the rotational speed of the collector roller is set at 100 rpm, and the flow rate of the solution is 2 mL / h. Under the action of the electric field, the solvent rapidly evaporates to form a continuous TPU fiber film, and the TPU fiber film is finally vacuum - dried at room temperature for 12 hours to remove the residual solvent, obtaining the TPU fiber film.

[0077] (2) Prepare the composite film layer

[0078] Using a heating-type flat coating machine, 0.5 mL of an aqueous dispersion of multi-walled carbon nanotubes was uniformly coated on a TPU fiber membrane at a speed of 5 mm / s. Among them, the average diameter of the multi-walled carbon nanotubes was 15 nm, the average length was 10 μm, and the solid content was 10 wt%; the dispersant was polyvinylpyrrolidone with a content of 2 wt%.

[0079] The TPU fiber membrane was previously cut into a size of 30 mm × 100 mm. After coating, the membrane was fixed on a flat surface and dried for 3 hours in a room-temperature environment with low humidity of 45% and good ventilation. The dried membrane was further cut into 30 mm × 30 mm segments, and copper foils were attached to both ends as electrode materials.

[0080] Then, these membrane pieces were installed on a tensile testing machine for two-way stretching in the longitudinal and transverse directions at a stretching rate of 2 mm / s. After stretching to 100% strain, it was released, and the stretching was performed once. Through the method of two-way stretching, a micro-cracked MWCNTs membrane with a micro-scale crack structure was formed on the surface of the membrane pieces, thereby obtaining a composite membrane layer. The thickness of the micro-cracked MWCNTs membrane was 5 μm, and the average crack spacing was 100 μm.

[0081] (3) Preparation of a micro-conical PDMS membrane layer

[0082] First, select fresh Broussonetia papyrifera leaves as a template with a micro-conical structure. The leaves were thoroughly cleaned with deionized water and air-dried at room temperature for 20 - 30 minutes, then cut into 25 mm × 25 mm segments and fixed to the bottom of the mold with UV glue. Then, Sylgard 184 (Sylgard 184 is a two-component product including a matrix and a curing agent) was mixed at a mass ratio of 5:1 of the matrix to the curing agent, degassed, and poured above the leaves with a thickness of at least 3 mm, and cured in a vacuum environment at 65 °C and 0.9 bar for 4 hours. After curing, the PDMS negative mold was carefully removed and ultrasonically cleaned with 70% ethanol to remove the residual leaf material. To avoid the formation of too strong chemical bonds between the PDMS negative mold and the subsequent coating, a thin gold film was sprayed on the surface of the negative mold using a magnetron sputtering device for 120 seconds. The prepared PDMS negative mold was used as a mold with a micro-conical structure for subsequent use. In the PDMS negative mold, the average diameter of the micro-cones was 120 μm, and the height was 100 μm.

[0083] Subsequently, PDMS mixed at a mass ratio of 10:1 of the matrix to the curing agent of Sylgard 184 was poured into the PDMS negative mold and cured again in a vacuum environment at 65 °C and 0.9 bar for 2 hours, finally obtaining a micro-conical PDMS membrane layer imitating the micro-conical structure of Broussonetia papyrifera leaves.

[0084] (4) Assembly of a flexible piezoresistive sensor

[0085] Stack the microconical PDMS film layer, the composite film layer, and the PDMS film layer in sequence from bottom to top; then wrap the above-stacked film layers with a PU film in the middle, that is, the lower part of the microconical PDMS film layer is in close contact with the first PU film layer, and the upper part of the PDMS film layer is in close contact with the second PU film layer.

[0086] The PDMS film layer is obtained by uniformly mixing Sylgard 184 according to a mass ratio of matrix to curing agent of 10:1 and curing it in a vacuum environment of 65°C and 0.9 bar for 2 hours.

[0087] Among them, the side of the microconical PDMS film layer with the bionic microconical structure is in contact with the TPU fiber membrane.

[0088] The thickness of the microconical PDMS film layer is 0.5 mm, the thickness of the TPU fiber membrane is 150 μm, the thickness of the microcrack MWCNTs film is 5 μm, and the thickness of the PDMS film layer is 0.5 mm. The first PU film layer and the second PU film layer are the same, both are medical-grade PU films, and their thicknesses are both 0.1 mm.

[0089] Example 2, a flexible piezoresistive sensor is prepared by the following steps.

[0090] (1) Prepare the TPU fiber membrane

[0091] Dry the TPU particles (WHT-1180; TPU thermoplastic elastomer; specific gravity: 1.18 g / cm 3 ) in a vacuum oven at 80°C for 24 hours to remove the moisture therein. Subsequently, dissolve the TPU particles in a mixed solvent of DMF and tetrahydrofuran (THF) at a concentration of 20 wt%, and the volume ratio of DMF to THF is 1:1. The dissolution process is carried out at 80°C and magnetically stirred for 8 hours to ensure complete dissolution of the particles to obtain a TPU solution.

[0092] Next, use an electrospinning device, place the prepared TPU solution in a 10 mL syringe equipped with a 20-gauge blunt needle, and precisely control the flow of the solution through a digital injection pump. The electrospinning process is carried out in an environment of room temperature and 60% humidity, apply a voltage of 14 kV, keep the distance between the needle and the collector at 12 cm, set the rotation speed of the collector roller to 100 rpm, and the flow rate of the solution is 1 mL / h. Under the action of the electric field, the solvent evaporates rapidly to form a continuous TPU fiber membrane, and the TPU fiber membrane is finally vacuum dried at room temperature for 12 hours to remove the residual solvent to obtain the TPU fiber membrane.

[0093] (2) Prepare the composite film layer

[0094] The heating type flat coater was used to evenly coat 0.1 mL of the aqueous dispersion of multi-walled carbon nanotubes on the TPU fiber membrane at a speed of 5 mm / s. Among them, the average diameter of the multi-walled carbon nanotubes was 10 nm, the average length was 15 μm, and the solid content was 8 wt%; the dispersant was polyvinylpyrrolidone with a content of 1.8 wt%.

[0095] The TPU fiber membrane was previously cut into a size of 30 mm × 100 mm. After coating, the membrane was fixed on a flat surface and dried for 3 hours in a room temperature environment with low humidity of 45% and good ventilation. The dried membrane was further cut into 30 mm × 30 mm segments, and copper foils were attached to both ends as electrode materials respectively.

[0096] Then, these membrane pieces were installed on a tensile testing machine for bidirectional stretching in the longitudinal and transverse directions. The stretching rate was 1.5 mm / s. After stretching to 100% strain and then releasing, the stretching was carried out 1 time. Through the method of bidirectional stretching, a microcrack MWCNTs membrane with a micron-level crack structure was formed on the surface of the membrane piece, thereby obtaining a composite membrane layer. The thickness of the microcrack MWCNTs membrane of the microcrack MWCNTs membrane was 1 μm, and the average crack spacing was 84 μm.

[0097] (3) Preparation of the microcone PDMS membrane layer

[0098] First, fresh Broussonetia papyrifera leaves were selected as the template with a microcone structure. The leaves were thoroughly cleaned with deionized water and air-dried at room temperature for 20 - 30 minutes and then cut into 25 mm × 25 mm segments, which were fixed to the bottom of the mold with UV glue. Then, Sylgard 184 was mixed according to a mass ratio of matrix to curing agent of 5:1, degassed, and poured above the leaves with a thickness of not less than 3 mm, and cured in a vacuum environment at 65 °C and 0.9 bar for 4 hours. After curing, the PDMS negative mold was carefully taken out and ultrasonically cleaned with 70% ethanol to remove the remaining leaf materials. To avoid the formation of too strong chemical bonds between the PDMS negative mold and the subsequent coating, a thin gold film was sprayed on the surface of the negative mold with a magnetron sputtering device for 120 seconds. The obtained PDMS negative mold was used as the mold with a microcone structure for subsequent use. In the PDMS negative mold, the average diameter of the microcones was 100 um, and the height was 80 um.

[0099] Subsequently, the PDMS mixed according to a mass ratio of 8:1 of matrix to curing agent was poured into the PDMS negative mold and cured again in a vacuum environment at 65 °C and 0.9 bar for 1.5 hours, finally obtaining the microcone PDMS membrane layer with a microcone structure imitating Broussonetia papyrifera leaves.

[0100] (4) Assembly of the flexible piezoresistive sensor

[0101] Stack the microcone PDMS film layer, the composite film layer, and the PDMS film layer in sequence from bottom to top; then wrap the above-stacked film layers with a PU film in the middle, that is, the bottom of the microcone PDMS film layer is in close contact with the first PU film layer, and the top of the PDMS film layer is in close contact with the second PU film layer.

[0102] The PDMS film layer is obtained by uniformly mixing Sylgard 184 according to a mass ratio of matrix to curing agent of 10:1 and curing it in a vacuum environment of 65 °C and 0.9 bar for 2 hours.

[0103] Among them, the side of the microcone PDMS film layer with the bionic microcone structure is in contact with the TPU fiber film.

[0104] The thickness of the microcone PDMS film layer is 0.2 mm, the thickness of the TPU fiber film is 100 μm, the thickness of the microcrack MWCNTs film is 1 μm, and the thickness of the PDMS film layer is 0.2 mm. The first PU film layer and the second PU film layer are the same, both are medical-grade PU films, and their thicknesses are both 0.05 mm.

[0105] Example 3, a flexible piezoresistive sensor is prepared by the following steps.

[0106] (1) Prepare the TPU fiber film

[0107] Dry the TPU particles (WHT-1180; TPU thermoplastic elastomer; specific gravity: 1.18 g / cm 3 ) in a vacuum oven at 80 °C for 24 hours to remove the moisture therein. Subsequently, dissolve the TPU particles in a mixed solvent of DMF and EAC at a concentration of 20 wt%, and the volume ratio of DMF to EAC is 3:1. The dissolution process is carried out at 80 °C and magnetically stirred for 8 hours to ensure complete dissolution of the particles to obtain a TPU solution.

[0108] Then, using an electrospinning device, place the prepared TPU solution in a 10 mL syringe equipped with a 20-gauge blunt needle, and precisely control the flow of the solution through a digital injection pump. The electrospinning process is carried out in an environment of room temperature and 60% humidity, applying a voltage of 16 kV, keeping the distance between the needle and the collector at 18 cm, setting the roller speed of the collector at 100 rpm, and the flow rate of the solution at 3 mL / h. Under the action of the electric field, the solvent quickly evaporates to form a continuous TPU fiber film, and the TPU fiber film is finally vacuum dried at room temperature for 12 hours to remove the residual solvent to obtain the TPU fiber film.

[0109] (2) Prepare the composite film layer

[0110] The TPU fiber membrane prepared by the same preparation process as the TPU fiber membrane was uniformly coated with 0.8 mL of an aqueous dispersion of multi-walled carbon nanotubes on the TPU fiber membrane at a speed of 5 mm / s using a heating type flat coater. Among them, the average diameter of the multi-walled carbon nanotubes was 25 nm, the average length was 5 μm, and the solid content was 12 wt%; the dispersant was polyvinylpyrrolidone, and the content was 2.2 wt%.

[0111] The TPU fiber membrane was previously cut into a size of 30 mm × 100 mm. After coating, the membrane was fixed on a flat surface and dried in a well-ventilated room temperature environment with low humidity of 45% for 3 hours. The dried membrane was further cut into 30 mm × 30 mm segments, and copper foils were attached to both ends as electrode materials respectively.

[0112] Then, these membrane pieces were installed on a tensile testing machine for two-way stretching in the longitudinal and transverse directions at a stretching rate of 2.5 mm / s. After stretching to 100% strain, it was released and stretched once. By means of two-way stretching, a microcrack MWCNTs membrane with a micron-scale crack structure was formed on the surface of the membrane piece, thereby obtaining a composite membrane layer. The thickness of the microcrack MWCNTs membrane was 8 μm, and the average crack spacing was 112 μm.

[0113] (3) Preparation of the microcone PDMS membrane layer

[0114] First, select fresh Broussonetia papyrifera leaves as a template with a microcone structure. The leaves were thoroughly cleaned with deionized water, air-dried at room temperature for 20 - 30 minutes, and then cut into 25 mm × 25 mm segments, which were fixed to the bottom of the mold with UV glue. Then, Sylgard 184 was mixed at a mass ratio of matrix to curing agent of 5:1, degassed, and poured above the leaves with a thickness of not less than 3 mm, and cured in a vacuum environment of 65 °C and 0.9 bar for 4 hours. After curing, the PDMS negative mold was carefully taken out and ultrasonically cleaned with 70% ethanol to remove the residual leaf material. To avoid the formation of too strong chemical bonds between the PDMS negative mold and the subsequent coating, a thin gold film was sprayed on the surface of the negative mold using a magnetron sputtering device for 120 seconds. The prepared PDMS negative mold was used as a mold with a microcone structure for subsequent use. In the PDMS negative mold, the average diameter of the microcones was 150 μm, and the height was 120 μm.

[0115] Subsequently, PDMS mixed at a mass ratio of matrix to curing agent of 12:1 was poured into the PDMS negative mold and cured again in a vacuum environment of 65 °C and 0.9 bar for 3 hours, finally obtaining a microcone PDMS membrane layer with a microcone structure imitating Broussonetia papyrifera leaves.

[0116] (4) Assembly of the flexible piezoresistive sensor

[0117] Stack the micro-cone PDMS film layer, the composite film layer, and the PDMS film layer in sequence from bottom to top; then wrap the above-stacked film layers with a PU film in the middle, that is, the bottom of the micro-cone PDMS film layer is in close contact with the first PU film layer, and the top of the PDMS film layer is in close contact with the second PU film layer.

[0118] The PDMS film layer is obtained by uniformly mixing Sylgard 184 according to a mass ratio of matrix to curing agent of 10:1 and then curing it in a vacuum environment of 65 °C and 0.9 bar for 2 hours.

[0119] Among them, the side of the micro-cone PDMS film layer with the bionic micro-cone structure is in contact with the TPU fiber film.

[0120] The thickness of the micro-cone PDMS film layer is 1 mm, the thickness of the TPU fiber film is 200 μm, the thickness of the micro-crack MWCNTs film is 10 μm, and the thickness of the PDMS film layer is 1 mm. The first PU film layer and the second PU film layer are the same, both are medical-grade PU films, and the thickness of both is 0.15 mm.

[0121] At the same time, the following Comparative Examples 1-9 are set according to Example 1, and the differences between Comparative Examples 1-9 and Example 1 are shown in the following table. Comparative Examples 1-9 are prepared into flexible piezoresistive sensors by the same method as Example 1.

[0122] Table 1 Differences between Example 1 and Comparative Examples 1-9

[0123]

[0124]

[0125] Among them, the short service life of the flexible piezoresistive sensor prepared in Comparative Example 1 is mainly because the direct contact between the micro-cone structure and the micro-crack MWCNTs film is not conducive to the service life of the sensor. Specifically, although the surface energy of PDMS is extremely low, some carbon nanotubes will still adhere to it during use, causing loss of the carbon nanotube film; the PDMS with the micro-cone structure has more destructive structural features and a larger contact surface area than the PDMS layer without structure, which will damage the carbon nanotube layer to a greater extent, resulting in problems such as unstable electrical signal response of the sensor and reduced service life of the sensor under long-term use.

[0126] Perform strain tests on the micro-cone PDMS film layer prepared in Example 1, the micro-pyramid PDMS film layer prepared in Comparative Example 2, the micro-cylinder PDMS film layer prepared in Comparative Example 3, and the micro-prism PDMS film layer prepared in Comparative Example 4.

[0127] The strain test conditions were as follows: The finite element method (FEM) was used to simulate the mechanical response under compression, and the stress distribution and strain behavior of the microstructure on PDMS were evaluated by the general simulation software COMSOL Multiphysics. The simulation was based on an accurate hyperelastic compression model of PDMS, using the Mooney-Rivlin 5-parameter model (material parameters: C01 = 114.08 [kPa], C02 = -269.88 [kPa], C10 = 145.06 [kPa], C11 = 450.72 [kPa], C20 = 156.23 [kPa]).

[0128] In Figure 5 which, from left to right, are the strain test results of the microcone PDMS film layer prepared in Example 1, the microprism PDMS film layer prepared in Comparative Example 2, the microcylinder PDMS film layer prepared in Comparative Example 3, and the microprism PDMS film layer prepared in Comparative Example 4; combined with In Figure 5 and In Figure 6 it can be seen that the microcone PDMS film layer prepared in Example 1 has stronger pressure sensitivity.

[0129] The flexible piezoresistive sensors prepared in Examples 1-3 and Comparative Examples 5-9 were tested.

[0130] Testing equipment: Pressure testing machine / vibrator, multimeter / impedance analyzer, data acquisition system Testing environment: Room temperature environment

[0131] Testing method: 1. Fix the flexible sensor on the workbench of the pressure testing machine to ensure that the surface of the sensor is flat and free of warping.

[0132] 2. Use the pressure testing machine to gradually increase the pressure starting from 0 Pa, and the maximum test pressure is selected according to the stable performance range during sensor testing (for example, 0 - 200 kPa).

[0133] 3. At the same time, record the changes in the applied pressure and the output signal (resistance) of the sensor through the data acquisition system.

[0134] 4. Hold for several seconds at each pressure value to ensure that the output signal of the sensor is stable before recording.

[0135] 5. Conduct multiple repeated tests at different pressure points (such as 5 Pa, 10 Pa, 20 Pa, etc.) to ensure the reliability and repeatability of the data.

[0136] The test result data table is shown in the following table.

[0137] Table 2 Performance test result table of examples and comparative examples

[0138]

[0139] The flexible piezoresistive sensor prepared in Example 1 is as follows: Figure 3 As shown in the figure, the schematic diagram of the cyclic electrical signal response under different pressing degrees is as follows Figure 4 As shown, during 1.5s-7.5s, the flexible piezoresistive sensor is in a hard pressing state, and during 9s-15s, the flexible piezoresistive sensor is in a light pinching state.

[0140] As can be seen from the table above, Example 1 shows excellent sensitivity in the full pressure range of 0-200 kPa due to its optimized multi-walled carbon nanotube loading and highly uniform distribution. In particular, in the low pressure range (0-2.5 kPa), its sensitivity reaches -0.14004 kPa. -1 , far exceeding other examples and comparison examples, verifying its high efficiency in accurately measuring small pressure changes. This performance is achieved through sophisticated material engineering and advanced manufacturing technology, ensuring reliability and stability in a wide range of applications.

[0141] Example 2 attempts to reduce costs by reducing the amount of multi-walled carbon nanotubes, resulting in lower sensitivity than Example 1 in all pressure ranges, especially a significant decrease in performance in the low pressure range. The data of this example emphasizes that while trying to reduce costs, performance may be negatively affected. Example 3 improves sensitivity in the low pressure range by improving solvents and electrospinning technology and increasing the amount of multi-walled carbon nanotubes, but its performance in the medium to high pressure range still does not reach the level of Example 1, which shows that although the goal is to increase sensitivity in a specific range, performance in the medium to high pressure range needs to be optimized. Even local optimization needs to maintain attention to the full range of performance.

[0142] The PDMS film thickness of Comparative Example 5 is 20 μm, which is thinner than that of Example 1. Because a smaller material thickness allows for faster deformation, this thinner film design is intended to improve the sensitivity of the film, especially in the low pressure range. However, the results show that the performance is inferior to or close to that of Example 1 in all pressure ranges, because the thinner film cannot disperse the stress well to increase the conductive path, resulting in reduced sensitivity.

[0143] The thickness of the PDMS membrane layer in Comparative Example 6 reaches 1500 μm, which greatly enhances the stability of the structure, but at the same time is likely to limit the sensitivity, especially in applications that require rapid response to small pressure changes. This design choice may make the membrane more stable in the high pressure range, but the sensitivity and response speed in the low pressure range are much lower than those of Example 1.

[0144] Comparative Example 7 describes a MWCNTs composite membrane with a crack-free structure. The crack structure is designed to enhance the flexibility of the membrane and its responsiveness to different pressure changes. It can provide more deformation space at the microscopic level, allowing the membrane to distribute stress more effectively under pressure, and theoretically improve its sensitivity in all pressure ranges. Similar to the theoretical inference, the results show that the sensitivity of the crack-free structure in all ranges is inferior to that of Example 1 with a microcrack structure.

[0145] The MWCNTs composite membrane of Comparative Example 8 has a very thin thickness (0.2 μm) and a small crack spacing (78 μm). Although this ultra-thin film layer may help improve flexibility and fit, its sensitivity in the low pressure range is significantly reduced, mainly because the ultra-thin multi-walled carbon nanotube layer makes the tunneling resistance change very small. In the medium to high pressure range, this design leads to rapid membrane loss and performance degradation.

[0146] The MWCNTs composite film of Comparative Example 9 has a thickness of 10.5 μm and a crack spacing of 122 μm. This thicker film layer helps improve the overall durability and conductivity of the film. This structure may provide better force transmission and distribution, thereby improving sensitivity. However, the results show that the larger multi-walled carbon nanotube thickness and crack spacing in the medium and high pressure range limit its sensitivity, because the larger thickness and gap require a larger pressure deformation to achieve an effective conductivity path connection.

[0147] Combined with reference Figure 7 A smart glove includes a glove body and a flexible piezoresistive sensor, wherein the flexible piezoresistive sensor is attached to the glove body.

[0148] In order to facilitate signal transmission and conversion of the smart gloves, the smart gloves also include a main control board, which includes a fixed resistor, a single-chip microcomputer, a filter, an operational amplifier and a wireless communication module.

[0149] There are four flexible piezoresistive sensors, which are respectively attached to the glove body at the positions of the fingertips of human fingers except the thumb, and are used to identify and collect finger pressure signals; the flexible piezoresistive sensor has a resistor; each of the flexible piezoresistive sensors is connected in series with the fixed resistor to form a voltage divider circuit, which converts the change in resistance value into a change in voltage divider, and then passes through the filter and the operational amplifier in sequence to form a stable voltage signal, which is input into the single-chip microcomputer; the single-chip microcomputer is connected to the wireless communication module; the flexible piezoresistive sensor is the flexible piezoresistive sensor as described above.

[0150] The processed voltage signal is then fed into the microcontroller, which can convert the analog signal into a digital signal through its ADC interface. The microcontroller then analyzes these digital signals using a preset gesture recognition algorithm and finally outputs a signal representing a specific gesture.

[0151] The wireless communication module allows the main control board to establish a wireless connection with the Raspberry Pi on the drone. The microcontroller can initialize the serial port through the UART library, and then the wireless communication module is connected to the microcontroller through the serial port, wirelessly transmitting the gesture signal to the Raspberry Pi of the drone for further processing and response.

[0152] Among them, the connection circuits between the fixed resistor, microcontroller, operational amplifier, filter, wireless communication module, and flexible piezoresistive sensor are all integrated on the main control board; the main control board integrates a microcontroller, voltage division circuit, filter circuit, power supply circuit, and wireless communication module, etc. Its power supply circuit can adopt a battery power supply method, supporting two power supply methods: USB and embedded battery.

[0153] The operational amplifier is located between the filter and the microcontroller, isolating the impedance of the signal input from the filter and then transmitting it into the ADC pin of the microcontroller. It can prevent the subsequent circuit from affecting the output of the previous stage signal source, while keeping the voltage value of the signal unchanged, ensuring the stability of the signal, and preventing signal distortion and loss; the model of the operational amplifier can be selected as TLV9064.

[0154] The output voltage range of the voltage division circuit is calculated by the following formula:

[0155]

[0156] Among them, V out is the output voltage, V in is the power supply voltage, R1 is the fixed resistor, and R S is the variable resistance of the flexible piezoresistive sensor. The flexible piezoresistive sensor will change its resistance when pressed, and accordingly, a corresponding voltage value can be generated.

[0157] By pressing the fingertip position of the glove body corresponding to the fingers of the human body except the thumb with the thumb, the flexible piezoresistive sensor can be pressed. By pressing with different forces, the flexible piezoresistive sensor can transmit different voltage signals, thereby enabling intelligent control.

[0158] In a specific manner, the circuit schematic diagram during the application of the intelligent glove is as shown in the appendix Figure 8 , the power supply voltage V in flows through the resistance R s of the flexible piezoresistive sensor, passes through the voltage division circuit formed with the fixed resistor R1 and enters the filter C1, then passes through the operational amplifier T1 and inputs into the microcontroller D1, and then is transmitted to the wireless communication module.

[0159] Combined with reference Figure 3 , a drone gesture control method includes the following steps:

[0160] Step 1: Put on the intelligent glove on the hand and install the UAV instruction execution module on the UAV body;

[0161] The UAV instruction execution module includes a flight control module and a Raspberry Pi;

[0162] The Raspberry Pi receives the instruction signal, converts the instruction signal into a control signal for the corresponding flight mode of the UAV. Meanwhile, the Raspberry Pi is connected to the flight control module, and the flight control module controls the UAV body to complete various actions;

[0163] Step 2: By setting a threshold value, determine whether the flexible piezoresistive sensor is in a state of heavy pressing or light pinching;

[0164] Step 3: Input the combined state information of the flexible piezoresistive sensor into the single-chip microcomputer to obtain the gesture state corresponding to each combined information and the instruction corresponding to the gesture state;

[0165] Step 4: The executor makes corresponding gesture actions with the fingers as required, and the single-chip microcomputer transmits the instruction signal to the Raspberry Pi through the wireless communication module;

[0166] Step 5: After receiving the instruction signal, the Raspberry Pi converts the gesture action into a UAV control signal, thereby controlling the UAV to complete the instruction action.

[0167] After receiving the instruction signal, the Raspberry Pi can convert the signal of the gesture action into a UAV control signal through Dronekit and then control the flight action of the UAV.

[0168] The intelligent glove is the above-mentioned intelligent glove.

[0169] Among them, the Raspberry Pi has a wireless communication receiving module inside, which can receive signals; the Raspberry Pi also converts the signals.

[0170] Combined with reference Figure 9 , for the UAV gesture control method of the present application, after assembling the intelligent glove and the UAV hardware, gesture actions are performed. The intelligent glove can collect the signals transmitted by the gesture actions; after the single-chip microcomputer converts the signals, specific gesture signals are sent; the UAV Raspberry Pi can receive the gesture signals and convert them into corresponding signals in the flight control module; finally, the flight control module controls the movement of the UAV.

[0171] The present application provides a method for controlling a drone in cooperation with the above-mentioned intelligent glove, enabling the operator to directly control the drone to complete command actions by simply pressing the flexible piezoresistive sensor on the glove body. The operation method is simple, intuitive, and easy to learn, reducing the technical threshold for the operator; this gesture control method allows the operator to control through natural hand movements, not only making the operation more intuitive but also helping the operator maintain a comprehensive monitoring of the surrounding environment, enhancing the safety and efficiency of interaction.

[0172] Meanwhile, the intelligent glove can also be used in harsh environments, can accurately identify gesture changes, improve the control accuracy of the drone, and the environment does not affect its sensitivity and accuracy or has little impact on its sensitivity and accuracy, making the limitations of the intelligent glove small and having a broader application scenario.

[0173] Gestures and the commands corresponding to the gestures can be set according to actual needs, thereby providing a personalized and highly adaptable interaction solution for the operator.

[0174] For this reason, the present application provides the gesture states in the preferred step three and the commands corresponding to the gesture states, which are specifically as follows.

[0175] The gesture states in step three and the commands corresponding to the gesture states include:

[0176] When the thumb lightly pinches the index finger, the drone performs a descending operation;

[0177] When the thumb presses heavily on the index finger, the drone performs a landing operation;

[0178] When the thumb lightly pinches the middle finger, the drone performs a forward movement operation;

[0179] When the thumb presses heavily on the middle finger, the drone performs a backward movement operation;

[0180] When the thumb lightly pinches the ring finger, the drone performs a left flight operation;

[0181] When the thumb presses heavily on the ring finger, the drone performs a right flight operation;

[0182] When the thumb lightly pinches the little finger, the drone performs an ascending operation;

[0183] When the thumb presses heavily on the little finger, the drone performs a takeoff operation;

[0184] The pressure for the light pinch is 5 - 30 kPa, and the pressure for the heavy press is 80 - 200 kPa.

[0185] The drone gesture control method paired with the above-mentioned intelligent glove relies on gesture changes to control the drone, which can quickly and accurately reflect the actual operation intention of the operator, making the control of the drone more sensitive and precise; and can provide a personalized and highly adaptable interaction solution for the operator by inputting and modifying gesture commands, improving the operator's usage experience.

[0186] In summary, in the flexible piezoresistive sensor, intelligent glove and drone gesture control method of the present invention, the flexible piezoresistive sensor can quickly change its resistance value when subjected to force, thereby achieving fast response and high-sensitivity pressure detection, with high sensitivity and precision, capable of accurately capturing and transmitting tiny pressure changes, and can be applied to the intelligent glove using the drone gesture control method to sensitively sense the pressure changes brought about by gesture changes, so as to precisely control the drone.

[0187] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A flexible piezoresistive sensor, characterized in that, It includes a micro-conical polydimethylsiloxane film layer, a composite film layer, and a polydimethylsiloxane film layer stacked in sequence from bottom to top; Among them, the composite film layer includes a thermoplastic polyurethane elastomer fiber film and a micro-cracked multi-walled carbon nanotube film. The thermoplastic polyurethane elastomer fiber film is attached to the micro-conical polydimethylsiloxane film layer, and the micro-cracked multi-walled carbon nanotube film is attached to the polydimethylsiloxane film layer; conductive electrode materials are attached to both ends of the micro-cracked multi-walled carbon nanotube film; The preparation steps of the composite film layer include: coating an aqueous dispersion of multi-walled carbon nanotubes on the thermoplastic polyurethane elastomer fiber film, drying and then stretching and rebounding to obtain the composite film layer with a micro-cracked multi-walled carbon nanotube film; the thickness of the micro-cracked multi-walled carbon nanotube film is 1 - 10 μm; The preparation steps of the micro-conical polydimethylsiloxane film layer include: mixing the polydimethylsiloxane matrix and the curing agent evenly, pouring them into a mold with a micro-conical structure, curing and then taking out to obtain the micro-conical polydimethylsiloxane film layer; the thickness of the micro-conical polydimethylsiloxane film layer is 0.2 - 1 mm; The preparation steps of the thermoplastic polyurethane elastomer fiber film include: dissolving the thermoplastic polyurethane elastomer in an organic mixed solvent to obtain a thermoplastic polyurethane elastomer solution, and electrospinning the thermoplastic polyurethane elastomer solution to obtain the thermoplastic polyurethane elastomer fiber film; The organic mixed solvent is selected from at least one of the mixture of dimethylformamide and ethyl acetate, and the mixture of dimethylformamide and tetrahydrofuran; In the thermoplastic polyurethane elastomer solution, the mass fraction of the thermoplastic polyurethane elastomer is 18 - 25 wt%; The parameters of the electrospinning process are: voltage of 14 - 16 kV, distance between the needle and the collector of 12 - 18 cm, and the flow rate of the thermoplastic polyurethane elastomer solution is 1 - 4 mL / h; In the preparation steps of the composite film layer, the aqueous dispersion of multi-walled carbon nanotubes contains multi-walled carbon nanotubes and a dispersant. The mass fraction of the multi-walled carbon nanotubes is 8 - 12 wt%, and the mass fraction of the dispersant is 1 - 4 wt%; The diameter of the multi-walled carbon nanotubes is 10 - 25 nm, and the length is 5 - 15 μm; The crack spacing of the micro-cracked multi-walled carbon nanotube film is 80 - 120 μm.

2. The flexible piezoresistive sensor according to claim 1, characterized in that, The thickness ratio of the micro-conical polydimethylsiloxane film layer, the micro-cracked multi-walled carbon nanotube film, the thermoplastic polyurethane elastomer fiber film, and the polydimethylsiloxane film layer is: (200 - 1000) : (1 - 10) : (50 - 200) : (200 - 1000).

3. The flexible piezoresistive sensor according to claim 1, wherein In the preparation steps of the micro-conical polydimethylsiloxane film layer, the mass ratio of the polydimethylsiloxane matrix to the curing agent is (8 - 12) :

1.

4. The flexible piezoresistive sensor according to claim 1, wherein, The flexible piezoresistive sensor further includes a first polyurethane film layer and a second polyurethane film layer. The first polyurethane film layer is disposed below the microconical polydimethylsiloxane film layer, and the second polyurethane film layer is disposed above the polydimethylsiloxane film layer. The thickness of the first polyurethane film layer is 50 - 150 μm, and the thickness of the second polyurethane film layer is 50 - 150 μm.

5. An intelligent glove, characterized in that, It includes a glove body and the flexible piezoresistive sensor according to any one of claims 1 to 4; the flexible piezoresistive sensor is attached to the glove body.

6. The intelligent glove according to claim 5, wherein The intelligent glove further includes a main control board, and the main control board includes a fixed resistor, a single-chip microcomputer, a filter, an operational amplifier, and a wireless communication module. There are four flexible piezoresistive sensors, which are respectively attached to the pulp positions of the fingers of the glove body corresponding to the fingers of the human body except the thumb, for identifying and collecting finger pressure signals. The single-chip microcomputer is connected to the wireless communication module. The flexible piezoresistive sensor has a resistance. Each flexible piezoresistive sensor is connected in series with the fixed resistor to form a voltage division circuit, which converts the change in resistance value into a change in voltage division, and then successively passes through the filter and the operational amplifier to form a stable voltage signal and inputs it into the single-chip microcomputer.

7. A method for controlling a drone by gestures, characterized in that, It includes the following steps: Step 1: Put on the intelligent glove on the hand, and install a drone instruction execution module on the drone body. The intelligent glove is the intelligent glove according to claim 6. The drone instruction execution module includes a flight control module and a Raspberry Pi. The Raspberry Pi receives the instruction signal and converts the instruction signal into a control signal for the corresponding flight mode of the drone. At the same time, the Raspberry Pi is connected to the flight control module, and the flight control module controls the drone body to complete various actions. Step 2: By setting a threshold, determine whether the flexible piezoresistive sensor is in a state of heavy press or light pinch. Step 3: Input the combined state information of the flexible piezoresistive sensor into the single-chip microcomputer to obtain the gesture state corresponding to each combined information and the instruction corresponding to the gesture state. Step 4: The executor makes corresponding gesture actions with the fingers as required, and the single-chip microcomputer transmits the instruction signal to the Raspberry Pi through the wireless communication module. Step 5: After the Raspberry Pi receives the instruction signal, it converts the gesture action into a drone control signal, thereby controlling the drone to complete the instruction action.

8. The drone gesture control method according to claim 7, characterized in that, The gesture states and the instructions corresponding to the gesture states in step 3 include: The thumb lightly pinches the index finger, and the drone executes a descending operation. The thumb heavily presses the index finger, and the drone executes a landing operation. The thumb lightly pinches the middle finger, and the drone executes a forward movement operation. The thumb heavily presses the middle finger, and the drone executes a backward movement operation. The thumb lightly pinches the ring finger, and the drone executes a left flight operation. The thumb heavily presses the ring finger, and the drone executes a right flight operation. The thumb lightly pinches the little finger, and the drone executes an ascending operation. The thumb heavily presses the little finger, and the drone executes a takeoff operation. The pressure for light pinch is 5 - 30 kPa, and the pressure for heavy press is 80 - 200 kPa.

Images