Sensing actuating system and method based on flexible sensor and thin film actuator and application

Abstract

The invention relates to the technical field of thin film actuators and flexible sensors, and provides a sensing actuating system and method based on a flexible sensor and a thin film actuator and application, and the sensing actuating system comprises a flexible capacitive pressure sensor, a double-layer thin film actuator and a central processing unit. The sensor detects object contact, and the central processing unit collects and processes changed capacitance signals and controls the actuator to conduct actuating bending. According to the sensor part, an AAO microstructure is introduced into a dielectric layer and matched with an ultra-thin electrode layer, micro stress detection can be achieved, electrode packaging integrated design is adopted in the whole, and the ultra-thin effect is achieved; the actuator part realizes multi-response actuation on the basis of a simple structure. According to the invention, by improving the preparation methods of the flexible capacitive pressure sensor and the double-layer film-shaped actuator, the ability of the sensor to detect micro stress and the ability of the actuator to respond to diversification are improved, the sensor and the actuator are directly and physically combined to form an integrated device, and the integrated device is matched with the central processing unit. Integrated operation of signal detection and feedback control can be achieved, and the device can be applied to the related fields of bionic animal and plant simulation, simulated grippers and the like.

Description

Technical Field

[0001] The present invention relates to the technical field related to flexible sensors and thin film actuators, and in particular to a sensing and actuation system, method and application based on flexible sensors and thin film actuators. Background Art

[0002] The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art.

[0003] With the continuous development of smart materials and smart systems, composite systems that integrate multiple sensing and actuation functions have shown great potential in many fields. Flexible capacitive pressure sensors can convert pressure into capacitive signals. They have good flexibility, fast response speed, and can provide real-time feedback of pressure information. They can be applied in a variety of scenarios. By introducing microstructures, the sensitivity of small pressure ranges can be greatly improved. However, existing technologies still have some problems in practical applications: ordinary pressure detection sensors generally have low sensitivity in the small pressure detection range, and although small pressure detection sensors have good sensitivity under small pressures, they do not work well in the normal pressure range.

[0004] Thin-film actuators can directly convert external stimuli into macroscopic force strain. Their thinness, light weight, and excellent flexibility allow them to achieve complex movements such as bending and folding, adapting to a variety of morphological changes. However, most existing thin-film actuators offer only single or dual responses, not specific multi-responses, limiting their application in diverse and complex environments. Furthermore, existing thin-film actuators combined with flexible sensors are relatively limited in form, failing to meet the demands of widespread application.

[0005] In summary, existing flexible capacitive pressure sensors and thin film actuators have some of the above-mentioned shortcomings in their respective fields, and their combined use still needs to be optimized. Summary of the Invention

[0006] In order to solve the above problems, the present invention proposes a sensing and actuation system, method and application based on flexible sensors and thin film actuators. By improving the preparation method of flexible capacitive pressure sensors and double-layer thin film actuators, the sensor's ability to detect tiny stresses and the actuator's diversified response are enhanced, and the two are directly physically combined to form an integrated device. When used with a central processing unit, it can realize the integrated operation of signal detection and feedback control, and can be applied to related fields such as bionic plant and animal simulation and simulated grippers.

[0007] In order to achieve the above-mentioned objectives, the present invention adopts the following technical solutions: one or more embodiments provide a sensing and actuation system based on a flexible sensor and a thin film actuator, including: a flexible capacitive pressure sensor, a double-layer thin film actuator and a central processing unit; the sensor detects contact with the object, the central processing unit collects and processes the changing capacitance signal, and controls the actuator to actuate the bending.

[0008] One or more embodiments provide a sensing and actuation method based on a flexible sensor and a thin film actuator, comprising the following steps:

[0009] Detecting contact with objects based on flexible sensors;

[0010] Compare the test results with the set values;

[0011] The actuator is electrically controlled and actuated according to the comparison result.

[0012] One or more embodiments provide sensing and actuation applications based on flexible sensors and thin film actuators, including: the sensing and actuation system can be considered as a bionic pitcher plant, where when the sensor detects contact with a tiny object, the actuator can bend quickly to grasp the object;

[0013] Alternatively, the three combined devices can be combined into a simulated gripper that pre-contacts the object, actuates it, and bends it to grasp the object.

[0014] Compared with the existing technology, the excellent effect of the present invention is: the present invention combines a flexible pressure sensor that still has high sensitivity within a certain small pressure range with a multi-response thin film actuator with a simple structure in a relatively stable physical combination, designs a sensing and actuation system, and applies it in the fields of bionic plants and animals and simulated grippers.

[0015] The central processing system collects the capacitance signal of the sensor, compares and judges the changing capacitance signal with the set value, controls the voltage output drive module to perform adaptive output, and then controls the film actuator to perform the required curling and grasping.

[0016] The advantages of the present invention and its additional aspects will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings constituting a part of the specification of this embodiment are used to provide a further understanding of this embodiment. The schematic embodiments and descriptions of this embodiment are used to explain this embodiment and do not constitute an improper limitation on this embodiment.

[0018] Figure 1 It is a schematic diagram of the three-dimensional structure of the sensor-actuator combination device;

[0019] Figure 2This is a flow chart for preparing the dielectric layer film of the flexible sensor;

[0020] Figure 3 is a flow chart for the preparation of thin film actuators;

[0021] Figure 4 This is the SEM (scanning electron microscope) image of the AAO microstructure of the flexible sensor dielectric layer;

[0022] Figure 5 is a cross-sectional SEM image of the thin film actuator;

[0023] Figure 6 This is an enlarged SEM image of the cross section of the nafion layer of the thin film actuator;

[0024] Figure 7 This is a comparative test chart of flexible sensors detecting micro stress;

[0025] Figure 8 This is a graph of the flexible sensor undergoing periodic loading tests under different pressures;

[0026] Figure 9 is the response time and recovery time of the flexible sensor;

[0027] Figure 10 This is a photothermal response test diagram of the thin film actuator;

[0028] Figure 11 This is the humidity response test graph of the thin film actuator;

[0029] Figure 12 This is a test diagram of the photothermal response recovery ability of the thin film actuator;

[0030] Figure 13 This is a test diagram of the humidity response recovery ability of the thin film actuator;

[0031] Figure 14 This is a comparison test diagram of the electrothermal performance of different electrode thicknesses on the thin film actuator;

[0032] Figure 15 This is a test diagram of the heat generation performance and electrothermal response recovery time of the thin film actuator after the electrode is introduced at a voltage of 3V;

[0033] Figure 16 It is a schematic diagram of the bionic pitcher plant composed of sensor and actuator devices and a combined diagram of the operating process of the sensor and actuator system;

[0034] Figure 17 It is a schematic diagram of a simulated mechanical gripper composed of sensing and actuating devices and a schematic diagram of release and grasping. Specific implementation plan

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0036] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0037] It should be noted that the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the exemplary embodiments according to the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof. It should be noted that, in the absence of conflict, the various embodiments in the present disclosure and the features in the embodiments can be combined with each other. The embodiments will be described in detail below with reference to the accompanying drawings.

[0038] In response to some technical problems existing in the above-mentioned background technology, the present invention designs a preparation method of a flexible capacitive pressure sensor and a flexible thin film multi-response actuator, as well as a physical combination method of the two. The flexible capacitive pressure sensor designed by the present invention not only has excellent performance under the normal pressure range, but also has relatively high sensitivity under a certain range of micro-pressures. Moreover, the overall structure of the sensor is simple and the thickness is relatively thin, which realizes the integration of electrode packaging and can be adapted to be attached to the surface of most objects. The flexible thin film multi-response actuator designed by the present invention can realize multi-response actuation on the basis of a simple structure, and has excellent response actuation capability and can be applied to a variety of scenarios. For the combination of the two, direct physical attachment is also adopted to ensure the stability and coordination of the combined device. In addition, the sensing and actuation system designed by the present invention can achieve good sensing feedback and better interpret the combination of sensing and actuation, so that it has excellent potential application value in the fields of bionic plants and animals. In the entire system, the sensor converts the pressure signal into a capacitance signal. The capacitance acquisition module, composed of an STM32 and FDC2214, collects the changing capacitance signal and transmits it to the central processing unit. The central processing unit calculates and judges the data, generating corresponding outputs for data reaching different thresholds. The voltage drive module, composed of an L298N and an external power supply, receives the output and generates an adaptive voltage output to control the actuator to achieve bending. This is explained below using a specific embodiment.

[0039] Example 1

[0040] In the technical solutions disclosed in one or more embodiments, Figures 1 to 16 As shown, the sensing and actuation system based on the flexible sensor and the thin film actuator includes: a flexible capacitive pressure sensor, a double-layer thin film actuator and a central processing unit;

[0041] The contact of the object is detected based on the flexible sensor; the detection result is compared with multiple set thresholds; and the actuator is electrically controlled and actuated according to the comparison result.

[0042] A further technical solution is a flexible capacitive pressure sensor comprising: upper and lower electrode layer films and an intermediate dielectric layer film;

[0043] The electrode layer film is a silver electrode film prepared by thermal evaporation of silver on the adhesive-coated surface of the PI tape; the dielectric layer film is an SBS / BaTiO3 / graphene film with an AAO microstructure. Optionally, SBS can be replaced by a hot-melt material such as PVDF or TPU, BaTiO3 can be replaced by a high dielectric constant material such as TiO2, LiNbO3, PbTiO3 or SrTiO3, and graphene can be replaced by a conductive material such as CNT or MXene.

[0044] Due to the inherent adhesiveness of PI tape, the dielectric layer film can be completely fixed and wrapped in it. The PI tape itself is also relatively thin, and the thickness of the plated electrode is about 150nm. Therefore, the electrode layer as a whole is very soft. Therefore, it can be deformed to a great extent under slight pressure, reducing the influence of the electrode layer's own toughness on deformation, and realizing the integration of the electrode layer and the outer packaging layer. Optionally, a thinner BOPP tape can be used instead of PI tape. Combined with the dielectric layer film after heat pressing, the overall thickness of the sensor can be controlled within 1cm.

[0045] The dielectric layer film uses a thermoplastic elastomer such as SBS as the base material. Adding an appropriate amount of graphene can effectively increase the effect of capacitance change, while adding an appropriate amount of barium titanate can increase the dielectric constant of the dielectric layer and reduce the dielectric loss caused by graphene. By introducing a 200nm AAO microstructure, the sensitivity of the sensor under a small stress range has been greatly improved. The SEM image of the micro-cone microstructure on the surface of the sensor dielectric layer is shown in the figure. Figure 4 As shown;

[0046] The flexible sensor in this embodiment not only has excellent performance under normal pressure ranges, but also has relatively high sensitivity under a certain range of micro-pressures. Moreover, the sensor has a simple overall structure and a thin thickness, and realizes an integrated electrode package, making it adaptable to be attached to the surface of most objects.

[0047] A further technical solution is a double-layer thin film actuator, comprising: a photothermal actuation film and a humidity actuation film;

[0048] The photothermal actuated film is a commercially available BOPP (biaxially oriented polypropylene) film tape with an overall thickness of approximately 60-80 microns. It features high transparency, high tensile strength, strong water resistance, excellent chemical stability, and ease of processing. It uses high-quality pressure-sensitive adhesive, which provides excellent initial and sustained adhesion, allowing for a stable bond with the humidity-activated film. Alternatively, PE tape, PE electrostatic adsorption film, or thermally expansive materials such as PVDF and PTFE can be used in place of the BOPP film tape.

[0049] The humidity-actuated membrane is a Nafion (perfluorosulfonic acid polymer) film doped with CNTs and MXene. Nafion has excellent chemical stability, can resist strong acids and alkalis, and has a unique microstructure. The Nafion molecule contains both hydrophilic sulfonic acid groups and hydrophobic perfluorocarbon chains, which gives it excellent water absorption and water loss capabilities; the incorporated CNTs have excellent photothermal conversion capabilities and can respond quickly to infrared light and ultraviolet light. Optionally, graphene can also be used instead of CNTs; with the incorporation of CNTs, the Nafion membrane as a whole will gradually become harder and affect the internal structure, causing the actuator's actuation bending ability to decrease, so MXene is incorporated. The addition of MXene can, on the one hand, improve Nafion's water absorption and, to a certain extent, alleviate the hardening problem caused by CNTs; CNTs and MXene both have good thermal conductivity and can promote heat transfer.

[0050] The cross-sectional SEM image of the actuator is shown in Figure 2. Figure 5 As shown, the upper part is the Nafion humidity response layer, and the lower part is the BOPP photothermal response layer. When the Nafion humidity response layer is enlarged, MXene and CNT are evenly distributed. The SEM image is as follows: Figure 6 shown.

[0051] The thin film actuator in this embodiment has a simple structure and consists of only two thin films with an overall thickness of about 150 microns. However, it can achieve multiple responses, including thermal actuation, photothermal actuation, humidity actuation, and ethanol solvent actuation. It can also be electrothermally actuated by combining an ultra-thin serpentine loop electrode on the surface. The photothermal actuation performance diagram is shown in FIG. Figure 10 As shown in the figure, the humidity actuation performance is as follows Figure 11 As shown in the figure; for different external stimuli, the film actuator has different bending actuation degrees, reflecting its good controllability and fast response speed. The photothermal response recovery ability and humidity response recovery ability are shown in the figure. Figure 12 、 Figure 13 shown.

[0052] A further technical solution is to use thermal evaporation to deposit a 180nm serpentine conductive silver electrode on one side of the Nafion membrane of the thin film actuator. Alternatively, a 180nm silver electrode can be sputtered on one side of the Nafion membrane by magnetron sputtering. The electrothermal performance comparison of different electrode thicknesses is shown in FIG. Figure 14 As shown, by comparing the effective working temperature range of the actuator, the thickness of the evaporation is finally determined to be 180nm, the heat generation effect at 3V voltage and the electrothermal response recovery time performance of the actuator are as follows Figure 15 As shown; the flexible sensor is cut into 0.8 cm squares and pasted to the open end of the conductive electrode using TPU hot melt adhesive; the selected TPU hot melt adhesive has a soft texture and good adhesion after melting into glue, and will not cause chemical damage to the actuator and sensor. Optionally, ultra-thin double-sided tape can be used instead of TPU hot melt adhesive for pasting.

[0053] Furthermore, a sensing and actuating method of a sensing and actuating system based on a flexible sensor and a thin film actuator comprises the following steps:

[0054] Detecting contact with objects based on flexible sensors;

[0055] Compare the detection results with multiple set thresholds;

[0056] The actuator is electrically controlled and actuated according to the comparison result.

[0057] In this embodiment, the flexible sensor can make real-time detection of some objects that can generate tiny pressure, and provide effective capacitance change signals, thereby accurately and quickly responding to the contact of the object. By comparing the detection results with multiple sets of pre-set thresholds, the central processing unit calculates and outputs different voltage drive signals, and then controls the voltage drive module to output the corresponding voltage, so that the actuator produces different degrees of bending deformation. This realizes automated sensing and actuation to a large extent, and the setting of multiple thresholds also ensures the accuracy and reliability of the overall system; the two are directly physically combined to form an integrated device, which can be used with the central processing unit to realize the integrated operation of signal detection and feedback control. It can be applied to related fields such as bionic plant and animal simulation and simulated grippers. The sensing and actuation system can be regarded as a bionic pitcher plant. When the sensor detects the contact of a tiny object, the actuator can bend quickly to grab the object. The relevant schematic diagram is shown in the figure. Figure 16 Alternatively, the three combined devices can be combined into a simulated gripper to pre-contact the object, actuator and bend to grasp the object, as shown in the relevant schematic diagram. Figure 17 shown.

[0058] Example 2

[0059] Based on Example 1, this embodiment provides a method for preparing a flexible capacitive pressure sensor in Example 1, such as Figure 2 、 Figure 4 、 Figures 7 to 9 As shown, the following steps are included:

[0060] Step 1: dissolving SBS particles in a mixed solution of N,N-dimethylformamide and tetrahydrofuran in a mass ratio of 1:3 to obtain a 10% SBS solution, and then adding graphene powder and magnetically stirring;

[0061] Step 2: Pour BaTiO3 powder into an appropriate amount of N,N-dimethylformamide solution and perform magnetic stirring and ultrasonic dispersion. After stirring evenly, add the mixed solution in step 1 and continue magnetic stirring. The mass ratio of SBS, graphene and BaTiO3 is 4:0.35:3;

[0062] Step 3: Pour the stirred solution into a glass culture dish, evaporate the solvent naturally at room temperature, cut into appropriate sizes and hot-press the AAO template to obtain a dielectric layer film with a microstructure. The specific model of the AAO template is VS450-100--400;

[0063] Step 4: Thermal evaporation silver is performed on the adhesive-coated surface of the PI tape to deposit a 150 nm thick layer of silver as a silver electrode; two silver electrodes are attached to the two sides of the dielectric layer film to obtain a prepared flexible capacitive pressure sensor;

[0064] In this embodiment, SBS is used as the substrate to ensure the chemical stability of the sensor dielectric layer film and improve the mechanical toughness. The combined use of graphene and barium titanate not only increases the dielectric constant but also reduces the dielectric loss. By introducing a 200nm AAO microstructure, the sensitivity of the sensor under a small stress range is greatly improved. In addition, the overall structure of the sensor is simple and thin, realizing the integrated electrode packaging.

[0065] In step 1, SBS is a styrene-butadiene-styrene block copolymer. SBS particles do not dissolve well in either N,N-dimethylformamide (DMF) or tetrahydrofuran (THF) alone. Mixing them in a mass ratio of 1:3 greatly improves the dissolution effect. During the stirring process, the temperature must be heated to around 100 degrees Celsius to effectively dissolve the SBS particles. Only after the SBS particles are completely dissolved can the graphene powder be added and stirred, otherwise the graphene will agglomerate.

[0066] In step 2, the nano-BaTiO3 powder is first dispersed in N,N-dimethylformamide to ensure that the mass ratio of SBS, graphene and BaTiO3 is 4:0.35:3. The BaTiO3 dispersion is first magnetically stirred at room temperature for 8 hours, and then ultrasonicated in cold water for two hours to promote dispersion; after the ultrasonication, it is quickly added to the SBS solution and continued to mix and stir with the graphene;

[0067] In step 3, the mixed solution is magnetically stirred for 12 hours and then poured into a glass culture dish. It is best to evaporate the solvent in a fume hood or other environment with stable wind speed at room temperature. After drying, the entire film will have some wrinkles and grooves. It is necessary to preheat and press the surface to flatten it, and then place the AAO groove template on it. After hot pressing at 200°C for 20 minutes, the film is placed in a 50%-60% concentration NaOH solution to dissolve the AAO template and obtain an AAO microstructure with a micro-cone structure.

[0068] In step 4, thermal evaporation silver is plated on the adhesive surface of the PI tape, and the evaporation time is controlled within 20-30 minutes to ensure the tightness of the silver surface. Optionally, the adhesive surface can be pre-treated with plasma to increase the adhesion of the silver. Since the adhesive surface of the PI tape has its own adhesiveness, the reserved space can be directly pasted, and the two silver electrodes are attached to the two sides of the dielectric layer film relative to each other, wrapping the dielectric layer film.

[0069] The flexible capacitive sensor fabricated above integrates the electrode layer and the packaging layer, largely resolving the performance issue caused by the stacking of the electrode layer and the packaging layer, resulting in excessive device thickness. Due to its ultra-thin shell, the fabricated sensor can respond promptly to even small pressures, and the introduction of the AAO microstructure further enhances its ability to detect minute pressures.

[0070] When the pressure is very low, the electrode layer first contacts the top of the AAO microcone (SEM image as shown in Figure 2). Figure 4 As shown in Figure 3, as the pressure increases, the electrode layer begins to squeeze the microcone, and the area of contact with the dielectric layer becomes larger and larger, until the pressure reaches a level sufficient to completely flatten the microcone, causing the electrode layer to completely contact the dielectric layer. As the pressure continues to increase, the sensor with the AAO microstructure becomes almost the same as the sensor with an ordinary normal structure, and can continue to detect normal pressure.

[0071] like Figure 7 As shown in the figure, under a small pressure of 0.6Pa-6Pa, both the sensor with AAO microstructure and the sensor with normal structure can respond to a certain extent, but the response of the former is much stronger than that of the latter. As the pressure increases, the response of the two tends to be the same; as for normal pressure, Figure 8As shown in Figure 2, the sensor has a better response under pressures of 0.5kPa, 5kPa, and 20kPa, which proves that the prepared sensor can detect normal pressures. Regarding the response recovery time of the prepared sensor, as shown in Figure 2, Figure 9 As shown in the figure, the prepared sensor has a faster response recovery time.

[0072] Example 3

[0073] Based on Example 1, this embodiment provides a method for preparing a double-layer thin film actuator in Example 1, such as Figure 3 、 Figures 5 to 6 、 Figures 10 to 11 As shown, the following steps are included:

[0074] Step 1: Pour Nafion powder into an appropriate amount of DMAC solution, heat and stir magnetically until completely dissolved;

[0075] Step 2: Pour CNT into the Nafion solution prepared in step 1, perform magnetic stirring at room temperature, and after stirring evenly, perform the first ultrasonic dispersion;

[0076] Step 3: Dissolve the MXene powder in a small amount of water. After it is completely dissolved, pour it into the mixed solution ultrasonicated in step 2. Continue stirring at room temperature. After stirring evenly, perform a second ultrasonic dispersion.

[0077] Step 4: Pour the dispersed mixed solution into a glass culture dish, place it in a vacuum drying oven at high temperature to dry the solvent, and obtain a Nafion humidity-responsive film;

[0078] Step 5: Cut the film into appropriate sizes and attach it with PE tape, and then cut it according to the film size to obtain the prepared double-layer film actuator;

[0079] In this embodiment, Nafion is used as the base material. Nafion has excellent chemical stability, can resist strong acids and alkalis, and has a unique microstructure. The Nafion molecule contains both hydrophilic sulfonic acid groups and hydrophobic perfluorocarbon chains, which makes it have excellent water absorption and water loss capabilities; the incorporated CNTs have excellent photothermal conversion capabilities and can respond quickly to infrared light and ultraviolet light. However, with the incorporation of CNTs, the Nafion membrane as a whole will gradually become harder and affect the internal structure, causing the actuator's actuation bending ability to decrease, so MXene is incorporated. The addition of MXene can, on the one hand, improve the water absorption of Nafion and, to a certain extent, alleviate the hardening problem caused by CNTs; CNTs and MXene both have good thermal conductivity and can promote heat transfer.

[0080] Example 4

[0081] Based on Example 2, this embodiment provides a specific implementation of the method for preparing a capacitive pressure sensor of Example 2, including the following steps:

[0082] (A1) Dissolve 2 g of SBS particles in a 1:3 mixture of N,N-dimethylformamide and tetrahydrofuran (DMF), i.e., 4.5 g of DMF and 13.5 g of THF. The mixture is magnetically stirred at approximately 100°C and 500-600 rpm for 3-4 hours to obtain a 10% SBS solution. Then, remove 2 g of the SBS solution and add 0.035 g of graphene powder. The mixture is magnetically stirred at 700-800 rpm and 20°C-30°C for 6-8 hours to ensure uniform mixing.

[0083] (A2) Pour 0.3 g of BaTiO3 powder into 2-3 ml of N,N-dimethylformamide solution, and stir magnetically at 400-500 rpm at room temperature. After stirring for 3-4 hours, place the powder in an ultrasonic machine for ultrasonic dispersion for 1-1.5 hours. After uniform dispersion, add the powder to the SBS and graphene mixed solution, and continue magnetic stirring at 700-800 rpm at 20°C-30°C for 8-10 hours to ensure uniform stirring. The mass ratio of SBS, graphene, and BaTiO3 is 4:0.35:3.

[0084] (A3) Pour the stirred solution into a glass culture dish with an inner diameter of about 5 cm. Allow the solvent to evaporate naturally at room temperature in a fume hood. Take it out after 12 hours, cut it into pieces of appropriate size (1 cm * 1 cm) and pre-heat press it at 180°C. The hot pressing time is controlled at 10-15 minutes to flatten the surface. After pre-heat pressing, hot press the AA0 template. Place the AAO template microstructure side up and cover the cut sensor film on the template. Hot press it at 200°C for 20 minutes. At this point, the template and the film are tightly connected. Directly tearing it off will destroy the microstructure. Place the sensor film with the template in a 50%-60% NaOH solution. After 24 hours, wait for the AAO template to completely dissolve to obtain a dielectric layer film with a microstructure. The specific model of the AAO template is VS450-100--400, and the height of the microcone structure is about 200nm.

[0085] (A4) Cut the PI tape and turn it upside down. First, use plasma to treat the coated surface at a power of 10W and treat it with oxygen for 3-4 minutes to increase the adhesion of silver. Turn the treated PI tape upside down, leaving 0.5mm of space on both sides. Then evaporate silver for 20-30 minutes to deposit a 150nm thick layer of silver as a silver electrode. Select two silver electrodes, fix the lead wires to each with conductive silver paste, and then attach the two silver electrodes to the two sides of the dielectric layer film. Align and pinch to reserve a free tape area to obtain the prepared flexible capacitive pressure sensor.

[0086] Example 5

[0087] Based on Example 3, this embodiment provides a specific implementation of the method for preparing a capacitive pressure sensor of Example 3, including the following steps:

[0088] (A1) Pour 0.1 g of Nafion™ powder into 2-3 ml of N,N-dimethylformamide (DMAC) solution and stir magnetically at 400-500 rpm at 60°C-70°C for 1-1.5 hours until the Nafion™ powder is completely dissolved to obtain a Nafion™ solution.

[0089] (A2) Pour 0.067 g of CNT (carbon nanotube) into the Nafion solution in (A1), and stir magnetically at room temperature and a speed of 600-700 rpm for 5 h. After stirring evenly, perform the first ultrasonic dispersion for 1 h.

[0090] (A3) Dissolve 0.33 g of MXene powder in 1 ml of water, shake evenly and completely dissolve, then pour into the ultrasonicated mixed solution in (A2). Continue magnetic stirring at room temperature and a speed of 600-700 rpm. After stirring for 7-8 hours, perform a second ultrasonic dispersion for 2.5 hours.

[0091] (A4) Pour the dispersed mixed solution into a glass Petri dish with an inner diameter of approximately 5 cm. Place the dish in a vacuum drying oven at 100°C to dry the solvent for approximately 2 hours. After cooling at room temperature for 5 minutes, pour an appropriate amount of deionized water (enough to cover the film) into the dish. After 2 minutes, use tweezers to peel the film off the Petri dish to obtain the Nafion humidity-responsive film.

[0092] (A5) Cut the film into 1*3 cm pieces and tightly adhere them with PE tape. Then, trim the excess tape according to the film size to obtain the prepared double-layer film-shaped actuator.

[0093] Example 6

[0094] Based on Example 1, this embodiment provides an implementation of the sensor and actuator combination method described in Example 1, including the following steps:

[0095] (A1) Thermally evaporate silver on one side of the Nafion membrane of the thin film actuator, cover it with a serpentine circuit mask template that is cut and printed by yourself, and evaporate a 180nm serpentine conductive silver electrode. The conductive electrode is as follows Figure 1 As shown in;

[0096] (A2) Cut the flexible sensor into 0.8cm squares and glue them to the open ends of the conductive electrode leads using TPU hot melt adhesive. Figure 1 As shown;

[0097] Example 7

[0098] Based on Example 1, this embodiment provides an implementation scheme of the sensing and actuation method of the sensing and actuation system based on the flexible sensor and the thin film actuator described in Example 1, including:

[0099] (A1) Detecting contact with an object based on a flexible sensor: When an object contacts the sensor, especially an object that can generate a small amount of pressure, the sensor can make a real-time detection and provide a capacitance change signal. When the sensor contacts an object, the sensor can also make a real-time detection and provide a capacitance change signal. These functions enable the sensor to accurately and quickly respond to object contact. In this embodiment, the acquisition circuit uses a capacitance acquisition module that combines an STM32C8T6 and an FDC2214.

[0100] (A2) Comparing the detection results with multiple set thresholds: The capacitance signal collected by the acquisition module is continuously input to the central processing unit, and the input capacitance signal is numerically compared with multiple groups (8-10 groups) of different thresholds pre-stored in the central processing unit;

[0101] (A3) Electrically controlling the actuator based on the comparison results: All comparison results are converted into different voltage drive signals and output to the L298N voltage drive module; the voltage drive module outputs corresponding voltages based on the different drive signals. Different voltages can generate different powers, thereby controlling the degree of bending of the actuator;

[0102] Example 8

[0103] The sensing and actuation system of Example 1 can be applied to many aspects such as bionic plants and animals, simulated grippers, etc., and has high sensitivity even under small pressures and can be used to detect small stresses.

[0104] Based on Example 1, this example provides an application of the sensing and actuation system based on the flexible sensor and the thin film actuator described in Example 1 in a bionic pitcher plant and a simulated mechanical assistant, such as Figure 16 and Figure 17 As shown;

[0105] Regarding the application of bionic pitcher plants, the combination form and method of the sensor and actuator are shown in Example 6. The sensor-attached side is upward and the actuator is placed flat. When an object similar to a tiny insect rests on the sensor, the voltage drive module will quickly apply a large voltage to increase the power, causing the actuator to quickly curl and grab the resting object. The specific scenario diagram is shown in the figure below. Figure 16 As shown;

[0106] Regarding the application of the simulated gripper, the sensor and the actuator are slightly separated. The specific structural diagram is as follows: Figure 17 As shown, three actuators coated with serpentine conductive paths are triangularly symmetrically attached to a base with sensors attached. When the sensor contacts an object, it is squeezed and the capacitance change signal is collected. Through threshold comparison, the corresponding signal is output to control the corresponding output of the external voltage, thereby performing adaptive grasping.

[0107] Compared with existing application system designs, most application systems can only be designed and apply sensors or thin film actuators separately. The few that can combine the two cannot achieve effective and reasonable integrated applications. However, the sensing and actuation system composed of a flexible capacitive pressure sensor and a double-layer thin film actuator directly physically combines the two to form an integrated device. When equipped with a central processing unit, it can realize the integrated operation of signal detection and feedback control, and can be effectively applied to related fields such as bionic plant and animal simulation and simulated grippers.

[0108] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

[0109] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without any creative work are still within the scope of protection of the present invention.

Claims

1. A sensing and actuation system based on a flexible sensor and a thin film actuator, characterized in that: include: Flexible capacitive pressure sensor, double-layer membrane actuator and central processing unit; The sensor detects the contact of the object, and the central processing unit collects and processes the changing capacitance signal to control the actuator to actuate the bending.

2. The sensing and actuation system based on a flexible sensor and a thin film actuator according to claim 1, characterized in that: The flexible sensor includes: upper and lower layers of electrode packaging integrated film and an intermediate dielectric layer film; The electrode packaging integrated film is a silver-plated PI electrode film; The dielectric layer film is a SBS / BaTiO3 / graphene film with an AAO microstructure.

3. The sensing and actuation system based on a flexible sensor and a thin film actuator according to claim 1, characterized in that: The thin film actuator includes: a photothermal actuation film and a humidity actuation film; The photothermal actuated film is a BOPP (biaxially oriented polypropylene) film tape; The humidity-actuated membrane is a Nafion (perfluorosulfonic acid polymer) film doped with CNTs and MXene.

4. The sensing and actuation system based on a flexible sensor and a thin film actuator according to claim 1, wherein: A conductive electrode is evaporated on one side of the humidity-actuated film of the thin film actuator and a flexible sensor is attached. The flexible sensor can detect the contact of an object, and combined with the central processor for calculation and output, the flexible actuator will then bend to grasp the object.

5. A sensing and actuating method of a sensing and actuating system based on a flexible sensor and a thin film actuator according to claims 1 to 4, characterized in that: Detecting contact with objects based on flexible sensors; Compare the detection results with multiple set thresholds; The actuator is electrically controlled and actuated according to the comparison result.

6. The sensing and actuating method of the sensing and actuating system based on the flexible sensor and the thin film actuator according to claim 5, characterized in that: A method for preparing a flexible capacitive pressure sensor comprises the following steps: SBS particles were dissolved in a mixed solution of N,N-dimethylformamide and tetrahydrofuran in a mass ratio of 1:3 to obtain a 10% SBS solution, graphene powder was added and magnetic stirring was performed. After stirring evenly, a separately stirred BaTiO3 suspension was poured into the solution. The mass ratio of SBS, graphene and BaTiO3 was 4:0.35:

3. After further magnetic stirring, the solution was poured into a glass Petri dish. The solvent was naturally evaporated at room temperature, and the solution was cut into appropriate sizes and hot-pressed with an AAO template to obtain a dielectric layer film. Thermal evaporation silver plating is performed on the adhesive-coated surface of the PI tape to deposit a layer of silver with a thickness of 150nm as a silver electrode; two silver electrodes are attached facing each other on both sides of the dielectric layer film to obtain the prepared flexible sensor.

7. The sensing and actuating method of the sensing and actuating system based on the flexible sensor and the thin film actuator according to claim 5, characterized in that: A method for preparing a double-layer thin film actuator comprises the following steps: Dissolve Nafion powder in DMAC solution, pour CNT and MXene aqueous solution into it, The mass ratio of Nafion, CNT, and MXene is specifically 3:2:

1. After being magnetically stirred evenly, it is ultrasonicated in ice water, poured into a glass Petri dish, and placed in an oven to dry the solvent. The film is cut into appropriate sizes and attached with PE tape.

8. The sensing and actuation application of the sensing and actuation system based on the flexible sensor and thin film actuator according to claims 1-4, characterized in that: Combination of flexible sensors and thin film actuators; Application form of sensor-actuated system.

9. The sensing and actuation application of the sensing and actuation system based on the flexible sensor and the thin film actuator according to claim 8, characterized in that: A 180nm serpentine conductive silver electrode was evaporated on one side of the Nafion membrane of the thin film actuator, and the flexible sensor was cut into 0.8cm squares and adhered to the open end of the conductive electrode using TPU hot melt adhesive.

10. The sensing and actuation application of the sensing and actuation system based on the flexible sensor and the thin film actuator according to claim 8, characterized in that: The sensor-actuation system can be thought of as a bionic pitcher plant. When the sensor detects a tiny object touching it, the actuator bends quickly to grab the object. Alternatively, three actuators and a sensor can be combined into a simulated gripper that pre-contacts the object, actuates the actuators, and bends to grasp the object.

Images