Three-electrode flexible strain tactile sensor and preparation method, circuit and system thereof

Abstract

The invention relates to a preparation method of a three-electrode flexible strain tactile sensor, a sensor, a circuit and a system. The method comprises the following steps: S1, depositing a first conductive film on a flexible substrate, leading out a first electrode from one side of the conductive film, and packaging the first electrode; s2, depositing a second conductive thin film with the same size as the first conductive thin film on coordinate paper by using a graphite pencil, and leading out a second electrode and a third electrode from the two sides of the second conductive thin film and packaging the second electrode and the third electrode; and S3, placing the first conductive thin film and the second conductive thin film in a mirroring manner by using a gasket, and packaging to form the three-electrode flexible strain tactile sensor. According to the scheme, the strain state and the tactile information of the sensor can be analyzed in a signal decoupling mode, the wiring complexity of the sensor can be reduced, meanwhile, the tactile and strain information can be kept to be detected in time, and the wide market application prospect is achieved.

Description

Technical Field

[0001] The present application relates to the field of hardware circuit design, and specifically to a three-electrode flexible strain tactile sensor and its preparation method, circuit and system. Background Art

[0002] Tactile information is information about the external environment acquired through sensory organs such as the skin. It primarily includes various sensory stimuli such as pressure, temperature, vibration, and strain. Strain, as a key component of tactile information, describes the degree of deformation of an object under external forces, helping users perceive the hardness, softness, and shape changes of an object through touch. Touch not only conveys the existence of an object and its physical properties, but also provides users with direct feedback on the environment, making it crucial in numerous application scenarios.

[0003] Tactile information is multimodal, providing users with rich feedback on object properties and environmental changes through the synergistic effects of different sensory channels. Tactile information plays a crucial role in cutting-edge fields such as robotics, virtual reality, and human-computer interaction. It not only significantly enhances user experience and improves operational precision, but also provides robots with more refined tactile perception, enabling them to better adapt to complex environments.

[0004] To effectively integrate multimodal tactile information, it is often necessary to construct a sensor network that organically combines different types of tactile sensors. In particular, the combination of strain sensors and touch sensors can greatly expand the dimensions of tactile information acquisition. However, the application of multimodal sensors in wearable devices or electronic skins faces numerous technical challenges, such as complex wiring and signal complexity. These challenges not only significantly increase the difficulty of system design and implementation but can also adversely affect the accuracy and response speed of the resulting tactile perception. Summary of the Invention

[0005] In view of the above problems, the present application provides a method for reverse designing a three-electrode flexible strain tactile sensor according to needs, so as to solve the problems of complex wiring and signal redundancy of existing tactile sensors.

[0006] In a first aspect, the present application provides a method for preparing a three-electrode flexible strain tactile sensor, comprising the following steps:

[0007] S1: depositing a first conductive film on a flexible substrate and leading out a first electrode on one side of the conductive film and encapsulating the first electrode;

[0008] S2: Using a graphite pencil, deposit a second conductive film having the same size as the first conductive film on graph paper, and lead out a second electrode and a third electrode on both sides of the second conductive film and encapsulate them;

[0009] S3: The first conductive film and the second conductive film are placed in a mirror-image manner using a gasket, and encapsulated to form a three-electrode flexible strain tactile sensor. The mirror-image setting includes: setting the first conductive film at the top, setting the second conductive film at the bottom, and maintaining a certain distance between the first conductive film and the second conductive film through the gasket.

[0010] Furthermore, step S1 includes:

[0011] A groove is formed by using adhesive tape, and a conductive copper-silver paste is applied in the groove to form the first conductive film. The adhesive tape is then removed, and a first electrode is led out from one side of the first conductive film.

[0012] The first conductive film leading to the first electrode is placed in an oven and baked at 120 degrees Celsius for 5 minutes to solidify the conductive copper-silver paste;

[0013] Polydimethylsiloxane is coated on the first electrode and placed in an oven for curing to complete the packaging of the first electrode.

[0014] Furthermore, the coordinate paper is a graph paper with an accuracy of 1 mm, and step S2 includes:

[0015] Draw a second conductive film with the same size as the first conductive film on the graph paper with a graphite pencil, and draw a second electrode and a third electrode on both sides with conductive copper-silver paste;

[0016] The second conductive film leading to the second electrode and the third electrode is placed in an oven and baked at 120 degrees Celsius for 5 minutes to solidify the conductive copper-silver paste;

[0017] Polydimethylsiloxane is coated on the second electrode and the third electrode respectively and placed in an oven for curing to complete the packaging of the second electrode and the third electrode.

[0018] In a second aspect, the present application provides a three-electrode flexible strain tactile sensor, which is prepared according to the preparation method described in the first aspect of the present application.

[0019] In a third aspect, the present application provides a voltage divider circuit, which is used to generate analog signals with different divided voltages, and includes:

[0020] The three-electrode flexible strain tactile sensor is the three-electrode flexible strain tactile sensor as described in the second aspect of the present application;

[0021] A voltage-dividing resistor is connected in series with the three-electrode flexible strain tactile sensor, and the voltage-dividing resistor is respectively connected to the second electrode and one end of the power module, and the third electrode is connected to the other end of the power module to form a first loop; or, the two voltage-dividing resistors are respectively connected to the second and third electrodes and the negative pole of the power module, and the first electrode of the three-electrode flexible strain tactile sensor is connected to the positive pole of the power module to form a second loop.

[0022] Furthermore, the resistance of the voltage-dividing resistor is half of the resistance of the second conductive film in the three-electrode flexible strain tactile sensor.

[0023] In a fourth aspect, the present application provides a control circuit, the control circuit comprising:

[0024] The voltage divider circuit is the voltage divider circuit as described in the third aspect of the present application;

[0025] The Arduino development board includes a power module, a digital-to-analog converter, and a microcontroller. The digital-to-analog converter is used to receive a voltage-divided analog signal from the voltage-dividing circuit and convert it into a digital signal. The microcontroller is used to process the digital signal. The power module is used to provide power for the voltage-dividing circuit, the digital-to-analog converter, and the microcontroller.

[0026] Furthermore, in the first circuit, the power module of the Arduino development board is connected to the second electrode of the three-electrode flexible strain tactile sensor, the voltage divider resistor is connected to the third electrode and connected to the GND port of the Arduino development board, and the analog port A0 of the analog-to-digital converter is connected to the third electrode of the three-electrode flexible strain tactile sensor.

[0027] In the second circuit, the power module of the Arduino development board is connected to the first electrode of the three-electrode flexible strain tactile sensor. Two voltage-dividing resistors are connected to the second and third electrodes respectively and connected to the GND port of the Arduino development board. The analog ports A0 and A1 of the analog-to-digital converter are connected to the second and third electrodes of the three-electrode flexible strain tactile sensor respectively.

[0028] In a fifth aspect, the present application provides a control system, comprising:

[0029] A control circuit, which is the control circuit as described in the fourth aspect of the present application;

[0030] The terminal device is communicatively connected with the microcontroller of the control circuit.

[0031] Furthermore, the communication connection mode is Bluetooth connection.

[0032] Different from existing technologies, the above technical solution involves a preparation method, sensor, circuit, and system for a three-electrode flexible strain tactile sensor. The method includes: S1: depositing a first conductive film on a flexible substrate, extending a first electrode from one side of the conductive film, and encapsulating the film; S2: depositing a second conductive film of the same size as the first conductive film on graph paper using a graphite pencil, extending a second electrode and a third electrode from both sides of the second conductive film, and encapsulating the film; S3: mirroring the first and second conductive films using spacers, and encapsulating the resulting three-electrode flexible strain tactile sensor. The above solution can analyze the sensor's strain state and tactile information through signal decoupling, reducing the complexity of the sensor's wiring while ensuring timely detection of tactile and strain information, and has broad market application prospects.

[0033] The above-mentioned records related to the content of the invention are only an overview of the technical solution of this application. In order to enable ordinary technicians in this field to understand the technical solution of this application more clearly, and then implement it according to the text of the specification and the contents recorded in the drawings, and to make the above-mentioned purposes and other purposes, features and advantages of this application easier to understand, the following is an explanation in combination with the specific implementation methods and drawings of this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The drawings are only used to illustrate the principles, implementation methods, applications, features and effects of the specific embodiments of the present invention and other related contents, and are not to be considered as limiting the present application.

[0035] In the drawings of the specification:

[0036] Figure 1 This is a flow chart of a method for preparing a three-electrode flexible strain tactile sensor according to a first exemplary embodiment of the present application;

[0037] Figure 2 This is a flow chart of a method for preparing a three-electrode flexible strain tactile sensor according to a second exemplary embodiment of the present application;

[0038] Figure 3 This is a flow chart of a method for preparing a three-electrode flexible strain tactile sensor according to a third exemplary embodiment of the present application;

[0039] Figure 4 A module diagram of a voltage divider circuit according to an exemplary embodiment of the present application;

[0040] Figure 5 is a schematic diagram of a control circuit involved in an exemplary embodiment of the present application;

[0041] Figure 6 A schematic diagram of a control system according to an exemplary embodiment of the present application;

[0042] Figure 7 is a schematic diagram of a first circuit involved in an exemplary embodiment of the present application;

[0043] Figure 8 is a schematic diagram of a second circuit involved in an exemplary embodiment of the present application;

[0044] Figure 9 This is a schematic diagram of the top structure of a three-electrode flexible strain tactile sensor according to an exemplary embodiment of the present application;

[0045] Figure 10 This is a schematic diagram of the bottom structure of a three-electrode flexible strain tactile sensor according to an exemplary embodiment of the present application;

[0046] Figure 11 This is a front view of a three-electrode flexible strain tactile sensor according to an exemplary embodiment of the present application;

[0047] Figure 12 This is a schematic diagram of the connection between the second conductive film and the second electrode and the third electrode according to an exemplary embodiment of the present application;

[0048] Figure 13 This is a module diagram of a physiological signal detection system in which the control system involved in Example 1 of the present application is a physiological signal detection system;

[0049] Figure 14 The control system involved in Example 2 of the present application is a module schematic diagram of a human-computer interaction system;

[0050] Figure 15 This is a module diagram of the control system involved in Example 3 of the present application, which is a robot electronic skin.

[0051] The reference numerals in the above drawings are described as follows:

[0052] 1. Conductive copper-silver paste; 2. Gasket; 31. First electrode; 32. Second electrode; 33. Third electrode; 4. Graphite; 5. Flexible substrate; 6. Coordinate paper; 7. Dimethylsiloxane;

[0053] 10. Voltage divider circuit; 100. Three-electrode flexible strain tactile sensor; 101. Voltage divider resistor;

[0054] 20. Arduino development board; 201. Power module; 202. Digital-to-analog converter; 203. Microcontroller;

[0055] 30. Control circuit; 40. Terminal device; 50. Control system. DETAILED DESCRIPTION

[0056] In order to explain in detail the possible application scenarios, technical principles, specific solutions that can be implemented, and the purpose and effects of this application, the following is a detailed description of the specific embodiments listed in conjunction with the accompanying drawings. The embodiments described herein are only used to more clearly illustrate the technical solutions of this application and are therefore only examples and are not intended to limit the scope of protection of this application.

[0057] References to "embodiments" herein mean that the specific features, structures, or characteristics described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the word "embodiment" in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or relevance to other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the various technical features mentioned in the embodiments can be combined in any manner to form a corresponding implementable technical solution.

[0058] Unless otherwise defined, the technical terms used herein have the same meanings as those generally understood by those skilled in the art to which this application belongs; the use of relevant terms herein is only for describing specific embodiments and is not intended to limit this application.

[0059] In the description of this application, the term "and / or" is used to describe a logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and both A and B exist. In addition, the character " / " in this document generally indicates that the objects before and after are in a logical "or" relationship.

[0060] In this application, terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual quantity, priority or sequence relationship between these entities or operations.

[0061] Without further limitations, in this application, the words "include", "comprise", "have" or other similar open-ended expressions used in sentences are intended to cover non-exclusive inclusion. These expressions do not exclude the presence of additional elements in the process, method or product that includes the elements, so that the process, method or product that includes a series of elements may include not only those defined elements, but also other elements that are not explicitly listed, or also include elements inherent to such process, method or product.

[0062] In this application, expressions such as "greater than," "less than," and "exceed" are understood to exclude the number itself; expressions such as "above," "below," and "within" are understood to include the number itself. In addition, in the description of the embodiments of this application, "multiple" means two or more (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups" and "multiple times," unless otherwise specifically limited.

[0063] In the description of the embodiments of the present application, the space-related expressions used, such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "vertical", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or position relationship based on the orientation or position relationship shown in the specific embodiments or drawings, and are only for the convenience of describing the specific embodiments of the present application or facilitating the reader's understanding, and do not indicate or imply that the device or component referred to must have a specific position, a specific orientation, or be constructed or operated in a specific orientation. Therefore, it should not be understood as a limitation on the embodiments of the present application.

[0064] Unless otherwise expressly specified or limited, in the description of the embodiments of the present application, the terms "installed", "connected", "connected", "fixed", "set", etc. used should be understood in a broad sense. For example, the "connection" can be a fixed connection, a detachable connection, or an integrated setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For those skilled in the art of the present application, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0065] The design principles of the present invention are as follows:

[0066] When selecting the strain signal detection and interaction architecture, the circuit diagram of the three-electrode flexible strain tactile sensor (i.e., the first circuit mentioned below, denoted as circuit 1) is as follows: Figure 7 As shown, the tactile sensor is mainly used to detect strain performance, and this function is mainly completed by the second conductive film. When the sensor is bent, the resistance R f Monotonically increasing. Assuming the gauge coefficient is α, the resistance of the second conductive film R f '=α1*R f , therefore, the bending degree of the sensor can be inferred according to the following formula:

[0067] α1=(UU A )*R / (U A *R f ).

[0068] When it is necessary to detect strain and touch information simultaneously, the circuit diagram of the three-electrode flexible strain tactile sensor (i.e., the second circuit mentioned below, denoted as circuit 2) is as follows: Figure 8 As shown, A is the first electrode of the three-electrode flexible strain tactile sensor, B and C are the second electrode and the third electrode respectively. Among them, the total resistance of the initial second conductive film R f =R f1 +R f2 When there is no external contact, it is equivalent to the virtual switch S being disconnected, and the circuit is in an open circuit state. At this time, no current will be generated in the entire circuit.

[0069] When the three-electrode flexible strain tactile sensor receives external mechanical stimulation, it is equivalent to the virtual switch S being closed. When the sensor bends, the resistance R f Monotonically increasing. Assuming the gauge factor is α2, the total resistance of the second conductive film is:

[0070] R f '=α2*R f =α2*(R f +R f2 );

[0071] Therefore, the bending degree of the tactile sensor can be inferred according to the following formula:

[0072] α2=[(UU B )*R1 / (U B *R f1 ')+(UU C )*R2 / (U C *R f2 ')] / R f ;

[0073] Assuming the total length of the second conductive film in the touch sensor is L, the position at the touch distance B can be calculated as:

[0074] L B =[(UU B )*R1 / U B ] / [(UU B )*R1 / U B +(UU C )*R2 / U C ]*L;

[0075] According to the above formula, the modes can be fused into the signal.

[0076] In the first aspect, Figure 1 As shown, the present application provides a method for preparing a three-electrode flexible strain tactile sensor, comprising the following steps:

[0077] S1: depositing a first conductive film on a flexible substrate and leading out a first electrode on one side of the conductive film and encapsulating the first electrode;

[0078] S2: Using a graphite pencil, deposit a second conductive film having the same size as the first conductive film on graph paper, and lead out a second electrode and a third electrode on both sides of the second conductive film and encapsulate them;

[0079] S3: The first conductive film and the second conductive film are placed in a mirror-image manner using a gasket, and encapsulated to form a three-electrode flexible strain tactile sensor. The mirror-image setting includes: setting the first conductive film at the top, setting the second conductive film at the bottom, and maintaining a certain distance between the first conductive film and the second conductive film through the gasket.

[0080] In some embodiments, as Figure 2 As shown, step S1 includes:

[0081] Step S201: using tape to form a groove, applying conductive copper-silver paste in the groove to form the first conductive film, and leading out a first electrode on one side of the first conductive film;

[0082] Step S202: placing the first conductive film leading to the first electrode into an oven and baking it at 120 degrees Celsius for 5 minutes to solidify the conductive copper-silver paste;

[0083] Step S203: coating the first electrode with polydimethylsiloxane and placing the first electrode in an oven for curing to complete the packaging of the first electrode.

[0084] In some embodiments, the coordinate paper is a graph paper with a precision of 1 mm, such as Figure 3 As shown, step S2 includes:

[0085] Step S301: using a graphite pencil to draw a second conductive film of the same size as the first conductive film on the graph paper, and using conductive copper-silver paste to draw out a second electrode and a third electrode on both sides thereof;

[0086] Step S302: placing the second conductive film from which the second electrode and the third electrode are drawn into an oven and baking at 120 degrees Celsius for 5 minutes to solidify the conductive copper-silver paste;

[0087] Step S303: Polydimethylsiloxane is coated on the second electrode and the third electrode respectively and placed in an oven for curing to complete the packaging of the second electrode and the third electrode.

[0088] The above scheme deposits a conductive copper-silver paste film strip on a flexible substrate (i.e., thermoplastic polyurethane), with an electrode drawn out on one side. A graphite pencil is then used to continuously scratch on coordinate paper to deposit a conductive graphite film of the same size as the conductive copper-silver paste film. Electrodes are then drawn out on both sides of the conductive graphite film using conductive copper-silver paste. Subsequently, tape is used as a spacer on both sides of the conductive graphite strip, placed face-to-face with the conductive copper-silver paste film strip, to form a three-electrode strain tactile sensor. The single electrode on the upper side is connected to the positive terminal of the power supply, while the dual electrodes on the lower side are connected to the negative terminal of the power supply.

[0089] By analyzing the ratio of the electrical signals generated by the two electrodes on the bottom side, the sensor's specific touch location can be determined, and by analyzing the overall electrical signal value, the sensor's specific bending degree can be determined. This three-electrode strain tactile sensor mathematically decouples the detection of bending degree from touch location, reducing the complexity of the tactile sensor's wiring while ensuring timely detection of tactile and strain information. It has broad application prospects in wearable devices and mechatronic skin.

[0090] In a second aspect, the present application further provides a three-electrode flexible strain tactile sensor, which is prepared according to the preparation method described in the first aspect of the present application.

[0091] In the third aspect, Figure 4 As shown, the present application provides a voltage divider circuit 10, which is used to generate analog signals with different divided voltages. The voltage divider circuit 10 includes:

[0092] The three-electrode flexible strain tactile sensor 100 is the three-electrode flexible strain tactile sensor as described in the second aspect of the present application;

[0093] A voltage-dividing resistor 101 is connected in series with the three-electrode flexible strain tactile sensor, and the voltage-dividing resistor is respectively connected to the second electrode and one end of the power module, and the third electrode is connected to the other end of the power module to form a first loop; or, the two voltage-dividing resistors are respectively connected to the second and third electrodes and the negative electrode of the power module, and the first electrode of the three-electrode flexible strain tactile sensor is connected to the positive electrode of the power module to form a second loop.

[0094] In some embodiments, the resistance of the voltage-dividing resistor is half the resistance of the second conductive film in the three-electrode flexible strain tactile sensor.

[0095] like Figure 5 As shown, in a fourth aspect, the present application provides a control circuit, the control circuit comprising:

[0096] The voltage divider circuit 10 is the voltage divider circuit described in the third aspect of the present application;

[0097] The Arduino development board 20 includes a power module 201, a digital-to-analog converter 202, and a microcontroller 203. The digital-to-analog converter 202 is used to receive the divided analog signal from the voltage divider circuit 10 and convert it into a digital signal. The microcontroller 203 is used to process the digital signal. The power module 201 is used to provide power to the voltage divider circuit 10, the digital-to-analog converter 202, and the microcontroller 203.

[0098] Preferably, the power supply voltage provided by the power module 201 is 5 V. The microcontroller can be implemented by software, hardware, firmware or a combination thereof, and can use at least one of a circuit, a single or multiple application-specific integrated circuits (ASIC), a digital signal processor (DSP), a digital signal processing device (DSPD), a programmable logic device (PLD), a field programmable gate array (FPGA), a central processing unit (CPU), and a microprocessor.

[0099] Preferably, in the first circuit, the power module of the Arduino development board is connected to the second electrode of the three-electrode flexible strain tactile sensor, the voltage divider resistor is connected to the third electrode and connected to the GND port of the Arduino development board, and the analog port A0 of the analog-to-digital converter is connected to the third electrode of the three-electrode flexible strain tactile sensor.

[0100] In the second circuit, the power module of the Arduino development board is connected to the first electrode of the three-electrode flexible strain tactile sensor. Two voltage-dividing resistors are connected to the second and third electrodes respectively and connected to the GND port of the Arduino development board. The analog ports A0 and A1 of the analog-to-digital converter are connected to the second and third electrodes of the three-electrode flexible strain tactile sensor respectively.

[0101] In the fifth aspect, Figure 6 As shown, the present application provides a control system 50, which includes:

[0102] The control circuit 30 is the control circuit as described in the fourth aspect of the present application;

[0103] The terminal device 40 is communicatively connected to the microcontroller 203 of the control circuit 30 .

[0104] Preferably, the communication connection is a Bluetooth connection. The control system can be a physiological signal detection system, a human-computer interaction system, a robot electronic skin, etc.

[0105] like Figures 9-15 As shown, the Hilbert sensor and its preparation method involved in this application are specifically described below in conjunction with Examples 1-3:

[0106] Example 1

[0107] In this embodiment, the preparation method includes the following steps:

[0108] (1) According to actual needs, the size of the three-electrode strain tactile sensor is determined to be 8 cm × 8 mm. A long strip of TPU of the same size is prepared. By sticking tape in advance, a 7 cm × 4 mm long strip pattern is reserved. Subsequently, a layer of conductive copper-silver paste with a thickness of 0.05 mm is scraped on the surface of the pattern, and the stuck tape is torn off to obtain a conductive copper-silver paste with a long strip pattern. An electrode (i.e., the first electrode) is drawn out at one end of the long strip pattern, and it is placed in an oven at 120 degrees Celsius and baked for 5 minutes to solidify the conductive copper-silver paste. Finally, the electrode is encapsulated with polydimethylsiloxane (PDMS), and the encapsulated electrode is placed in an oven at 120 degrees Celsius and baked for 2 minutes to ensure that the electrode will not be easily damaged by the outside world. At this point, the top of the three-electrode strain tactile sensor is completed.

[0109] (2) Use a graph paper with a precision of 1 mm as coordinate paper, and use a pencil to draw a 7 cm × 4 mm strip pattern on this graph paper to obtain a graphite conductive film. After drawing, use conductive copper-silver paste to lead out dual electrodes at the beginning and end of the strip pattern, and place it in an oven at 120 degrees Celsius for 5 minutes to solidify the conductive copper-silver paste. Finally, use PDMS to encapsulate the electrode and place it in an oven at 120 degrees Celsius for 2 minutes to ensure that the electrode will not be easily damaged by the outside world. On this basis, cut out the required sensor size. At this point, the bottom of the three-electrode strain tactile sensor is completed.

[0110] (3) Based on the top and bottom of the three-electrode strain tactile sensor obtained in steps (1) and (2), two pieces of double-sided tape with a width of 2 mm and a thickness of 0.2 mm are overlapped to form a gasket. Then, the top and bottom of the obtained tactile sensor are aligned and placed on the gasket in a mirror image. At this point, the construction of the three-electrode strain tactile sensor is completed.

[0111] (4)Reference Figures 9 to 12The prepared three-electrode strain tactile sensor includes a conductive copper-silver paste 1, graphite 4, a first electrode 31, a second electrode 32, and a third electrode 33, as well as a gasket 2 for constructing an active sensing interval, dimethylsiloxane 7 for encapsulating the electrodes, a flexible substrate 5, and graph paper 6. The working principle of the three-electrode strain tactile sensor is as follows: touching the top and bottom layers causes a change in the total resistance of the tactile sensor, and the change in resistance can be used to analyze the specific location of the touch; at the same time, the bending of the tactile sensor changes the total resistance of the sensor, and the bending deformation state of the tactile sensor can be analyzed. The three-electrode strain tactile sensor involved in this embodiment can be used to implement a real-time monitoring system for physiological signals.

[0112] (5) Please refer to Figure 13 , the three-electrode strain tactile sensor can be embedded into smart wearable devices (such as smart gloves) and Figure 7 The first circuit in Figure 13 The circuit (represented as Circuit 1) is connected to external components, including a voltage divider resistor, an Arduino development board, and a Bluetooth module. In this circuit design, the Arduino development board provides power (VCC), which is connected to the second electrode of the strain gauge tactile sensor. The voltage divider resistor is connected to the third electrode and then to the Arduino's GND port. The Arduino's A0 port then reads the analog signal between the voltage divider resistor and the strain gauge tactile sensor, converts it to a digital signal via a digital-to-analog converter, and transmits the signal to a processing terminal via the Bluetooth module.

[0113] The control system involved in this embodiment 1 can continuously read the analog signal of the A0 port according to a predefined program, and transmit the signal to the processing terminal through a digital-to-analog converter and a long-distance transmission device, thereby collecting physiological characteristic parameters of specific parts of the user and monitoring the user's health status in real time.

[0114] Example 2

[0115] In this embodiment, the preparation method includes the following steps:

[0116] (1) According to actual needs, the size of the three-electrode strain tactile sensor is determined to be 12 cm × 10 mm. A long strip of TPU of the same size is prepared. By sticking tape in advance, a long strip pattern of 11 cm × 6 mm is reserved. Subsequently, a layer of conductive copper-silver paste with a thickness of 0.05 mm is scraped on the surface of the pattern, and then the stuck tape is torn off to obtain a conductive copper-silver paste with a long strip pattern. An electrode is drawn out at one end of the long strip pattern and placed in an oven at 120 degrees Celsius for 5 minutes to solidify the conductive copper-silver paste. Finally, the electrode is encapsulated with PDMS and placed in an oven at 120 degrees Celsius for 2 minutes to ensure that the electrode will not be easily damaged by the outside world. At this point, the top of the three-electrode strain tactile sensor is completed.

[0117] (2) Use a graph paper with a precision of 1 mm as coordinate paper, and use a pencil to draw an 11 cm × 6 mm strip pattern on this graph paper to obtain the bottom resistor. After drawing, use conductive copper-silver paste to lead out double electrodes at the beginning and end of the strip pattern, and place it in an oven at 120 degrees Celsius for 5 minutes to solidify the conductive copper-silver paste. Finally, use PDMS to encapsulate the electrodes and place them in an oven at 120 degrees Celsius for 2 minutes to ensure that the electrodes will not be easily damaged by the outside world. On this basis, cut out the required size of the tactile sensor. At this point, the bottom of the three-electrode strain tactile sensor is completed.

[0118] (3) Based on the top and bottom of the tactile sensor obtained in steps (1) and (2), two pieces of double-sided tape with a width of 2 mm and a thickness of 0.2 mm are overlapped to form a gasket. Then, the top and bottom of the obtained tactile sensor are aligned and placed on the gasket in a mirror image. At this point, the construction of the three-electrode strain tactile sensor is completed.

[0119] (4)Reference Figures 9 to 12 The three-electrode strain tactile sensor obtained by the above method includes a conductive copper-silver paste 1, graphite 4, a first electrode 31, a second electrode 32, and a third electrode 33, as well as a gasket 2 for constructing an active sensing gap, polydimethylsiloxane 7 for encapsulating the electrodes, a flexible substrate 5, and graph paper 6. The working principle of the three-electrode strain tactile sensor is as follows: touching causes the top and bottom layers to contact, resulting in a change in the total resistance of the tactile sensor. Based on the change in total resistance, the specific location of the touch can be analyzed. The three-electrode strain tactile sensor involved in this embodiment can be used in remote human-computer interaction systems to realize the control of virtual characters in the interactive interface.

[0120] (5) Please refer to Figure 14 In practical applications, the three-electrode strain tactile sensor can be worn on the arm and Figure 8 The second circuit in Figure 8 The circuit (represented as Circuit 2) is connected to external components, including a voltage-dividing resistor, an Arduino development board, and a Bluetooth module. In the circuit design, the Arduino development board provides access to a built-in power supply (VCC), and analog ports A0 and A1 are connected to the second and third electrodes of the strain gauge tactile sensor, respectively. The voltage-dividing resistor forms a voltage-dividing circuit with the second and third electrodes of the strain gauge tactile sensor, with the other ends connected to ground. The tactile sensor and the voltage-dividing resistor generate different voltage-dividing analog signals, which are read by the Arduino development board's analog-to-digital converter and converted into digital signals, which are transmitted to the processing terminal via the Bluetooth module.

[0121] The control system involved in this embodiment 2 can divide the tactile sensor into four sensing areas according to a predefined program, corresponding to the four directions of front, back, left and right. When the user touches different positions of the sensor, corresponding analog signals will be generated. These analog signals are converted into digital signals by the digital-to-analog converter and transmitted to the terminal through the Bluetooth module for remote control of the movement of virtual characters in the human-computer interaction interface or performance of specific actions.

[0122] Example 3

[0123] In this embodiment, the preparation method includes the following steps:

[0124] (1) According to actual needs, the size of the three-electrode strain tactile sensor is determined to be 5 cm × 10 mm. A long strip of TPU of the same size is prepared. By sticking tape in advance, a 4 cm × 6 mm long strip pattern is reserved. Subsequently, a layer of conductive copper-silver paste with a thickness of 0.05 mm is scraped on the surface of the pattern, and then the stuck tape is torn off to obtain a conductive copper-silver paste with a long strip pattern. An electrode is drawn out at one end of the long strip pattern and placed in an oven at 120 degrees Celsius for 5 minutes to solidify the conductive copper-silver paste. Finally, the electrode is encapsulated with PDMS and placed in an oven at 120 degrees Celsius for 2 minutes to ensure that the electrode will not be easily damaged by the outside world. At this point, the top of the three-electrode strain tactile sensor is completed.

[0125] (2) Use a graph paper with a precision of 1 mm as coordinate paper, and use a pencil to draw a 4 cm × 6 mm strip pattern on this graph paper to obtain the bottom resistor. After drawing, use conductive copper-silver paste to lead out dual electrodes at the beginning and end of the strip pattern, and place it in an oven at 120 degrees Celsius for 5 minutes to solidify the copper-silver paste. Finally, use PDMS to encapsulate the electrodes and place them in an oven at 120 degrees Celsius for 2 minutes to ensure that the electrodes will not be easily damaged by the outside world. On this basis, cut out the required sensor size. At this point, the bottom of the three-electrode strain tactile sensor is completed.

[0126] (3) Based on the top and bottom of the tactile sensor obtained in steps (1) and (2), two pieces of double-sided tape with a width of 2 mm and a thickness of 0.2 mm are overlapped to form a gasket. Then, the top and bottom of the obtained tactile sensor are aligned and placed on the gasket in a mirror image. At this point, the construction of the three-electrode strain tactile sensor is completed.

[0127] (4)Reference Figures 9 to 12The three-electrode strain tactile sensor obtained by the above preparation method includes a conductive copper-silver paste 1, graphite 4, a first electrode 31, a second electrode 32, and a third electrode 33, a gasket 2 for constructing an active sensing interval, polydimethylsiloxane 7 for encapsulating the electrodes, a flexible substrate 5, and coordinate paper 6. The working principle of the three-electrode strain tactile sensor is as follows: by touching, the top and bottom layers come into contact, causing the total resistance of the tactile sensor to change, and the specific location of the touch can be analyzed based on the change in the total resistance; at the same time, the bending of the sensor will change the total resistance of the sensor, and the change in the total resistance can be used to analyze the bending deformation state of the sensor. The three-electrode strain tactile sensor involved in this embodiment can be applied to robot electronic skin.

[0128] (5) Please refer to Figure 15 In practical applications, the three-electrode strain tactile sensor can be attached to the robot's mechanical arm and Figure 8 The second circuit in Figure 8 The circuit (represented as Circuit 2) is connected to external components, including a voltage-dividing resistor, an Arduino development board, and a Bluetooth module. In the circuit design, the Arduino development board provides access to a built-in power supply (VCC), and analog ports A0 and A1 are connected to the second and third electrodes of the strain gauge tactile sensor, respectively. The voltage-dividing resistor forms a voltage-dividing circuit with the second and third electrodes of the strain gauge tactile sensor, with the other ends connected to ground. The tactile sensor and the voltage-dividing resistor generate different voltage-dividing analog signals, which are read by the Arduino development board's analog-to-digital converter and converted into digital signals, which are transmitted to the processing terminal via the Bluetooth module.

[0129] The control system involved in this embodiment 3 can sense and analyze the position of the robot when it is touched or actively touched, according to a predefined program, while also monitoring the bending condition of the robot arm in real time. When the robot is touched or actively touched, a corresponding analog signal is generated. This analog signal is converted into a digital signal by a digital-to-analog converter and sent to a terminal device via a Bluetooth module. The terminal device analyzes the digital signal and can determine the touch position. At the same time, the process of the robot bending its fingers generates a continuously changing signal. After the continuously changing signal is converted into a digital signal and synchronized to the terminal device, the terminal device can analyze the current bending condition of the robot's mechanical arm and thus identify the robot's motion state.

[0130] The beneficial effects of the present invention are as follows:

[0131] (1) The multifunctional three-electrode flexible strain tactile sensor proposed in the present invention adds an information dimension compared to traditional tactile and strain sensors, making it more versatile and having a wider range of applications;

[0132] (2) The three-electrode flexible strain tactile sensor proposed in the present invention significantly reduces its size and complexity through a design with fewer electrodes, thereby improving its comfort and adaptability in wearable devices;

[0133] (3) The three-electrode flexible strain tactile sensor proposed in the present invention has only two signal dimensions and does not generate any signal when there is no external contact, which has advantages in signal processing and simplification;

[0134] (4) The three-electrode flexible strain tactile sensor structure proposed in the present invention is scalable. Its core is a combination of high-conductivity film and low-conductivity film. In theory, as long as the process is met, a more sensitive sensor can be designed based on this.

[0135] (5) The three-electrode flexible strain tactile sensor proposed in the present invention can fuse tactile information from different areas, enabling the sensor to extract richer information from a small amount of signals, reducing dependence on single signal processing.

[0136] Finally, it should be noted that although the above embodiments have been described in the specification and drawings of this application, this does not limit the scope of patent protection of this application. All technical solutions generated by replacing or modifying equivalent structures or equivalent processes based on the essential concepts of this application using the contents recorded in the specification and drawings of this application, as well as directly or indirectly implementing the technical solutions of the above embodiments in other related technical fields, are included in the scope of patent protection of this application.

Claims

1. A method for preparing a three-electrode flexible strain tactile sensor, characterized in that: The following steps are involved: S1: depositing a first conductive film on a flexible substrate and leading out a first electrode on one side of the conductive film and encapsulating the first electrode; S2: Using a graphite pencil, deposit a second conductive film having the same size as the first conductive film on graph paper, and lead out a second electrode and a third electrode on both sides of the second conductive film and encapsulate them; S3: The first conductive film and the second conductive film are placed in a mirror-image manner using a gasket, and encapsulated to form a three-electrode flexible strain tactile sensor. The mirror-image setting includes: setting the first conductive film at the top, setting the second conductive film at the bottom, and maintaining a certain distance between the first conductive film and the second conductive film through the gasket.

2. The method for preparing the three-electrode flexible strain tactile sensor according to claim 1, wherein: Step S1 includes: A groove is formed by using adhesive tape, and a conductive copper-silver paste is applied in the groove to form the first conductive film. The adhesive tape is then removed, and a first electrode is led out from one side of the first conductive film. The first conductive film leading to the first electrode is placed in an oven and baked at 120 degrees Celsius for 5 minutes to solidify the conductive copper-silver paste; Polydimethylsiloxane is coated on the first electrode and placed in an oven for curing to complete the packaging of the first electrode.

3. The method for preparing the three-electrode flexible strain tactile sensor according to claim 1, wherein: The coordinate paper is a graph paper with an accuracy of 1 mm, and step S2 includes: Draw a second conductive film with the same size as the first conductive film on the graph paper with a graphite pencil, and draw a second electrode and a third electrode on both sides with conductive copper-silver paste; The second conductive film leading to the second electrode and the third electrode is placed in an oven and baked at 120 degrees Celsius for 5 minutes to solidify the conductive copper-silver paste; Polydimethylsiloxane is coated on the second electrode and the third electrode respectively and placed in an oven for curing to complete the packaging of the second electrode and the third electrode.

4. A three-electrode flexible strain tactile sensor, characterized in that: The three-electrode flexible strain tactile sensor Prepared according to the preparation method according to any one of claims 1 to 3.

5. A voltage divider circuit, characterized in that: The voltage divider circuit is used to generate analog signals with different divided voltages, and the voltage divider circuit includes: The three-electrode flexible strain tactile sensor is the three-electrode flexible strain tactile sensor according to claim 4; A voltage-dividing resistor is connected in series with the three-electrode flexible strain tactile sensor, and the voltage-dividing resistor is respectively connected to the second electrode and one end of the power module, and the third electrode is connected to the other end of the power module to form a first loop; or, the two voltage-dividing resistors are respectively connected to the second and third electrodes and the negative pole of the power module, and the first electrode of the three-electrode flexible strain tactile sensor is connected to the positive pole of the power module to form a second loop.

6. The voltage divider circuit according to claim 5, wherein: The resistance of the voltage-dividing resistor is half of the resistance of the second conductive film in the three-electrode flexible strain tactile sensor.

7. A control circuit, characterized in that: The control circuit comprises: The voltage divider circuit is the voltage divider circuit according to claim 6; The Arduino development board includes a power module, a digital-to-analog converter, and a microcontroller. The digital-to-analog converter is used to receive a voltage-divided analog signal from the voltage-dividing circuit and convert it into a digital signal. The microcontroller is used to process the digital signal. The power module is used to provide power for the voltage-dividing circuit, the digital-to-analog converter, and the microcontroller.

8. The control circuit according to claim 7, wherein: In the first circuit, the power module of the Arduino development board is connected to the second electrode of the three-electrode flexible strain tactile sensor, the voltage divider resistor is connected to the third electrode and connected to the GND port of the Arduino development board, and the analog port A0 of the analog-to-digital converter is connected to the third electrode of the three-electrode flexible strain tactile sensor. In the second circuit, the power module of the Arduino development board is connected to the first electrode of the three-electrode flexible strain tactile sensor. Two voltage-dividing resistors are connected to the second and third electrodes respectively and connected to the GND port of the Arduino development board. The analog ports A0 and A1 of the analog-to-digital converter are connected to the second and third electrodes of the three-electrode flexible strain tactile sensor respectively.

9. A control system, characterized in that: The control system includes: The control circuit is the control circuit according to claim 8; The terminal device is communicatively connected with the microcontroller of the control circuit.

10. The control system according to claim 9, wherein: The communication connection mode is Bluetooth connection.

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