Passive and wireless three-dimensional force sensor preparation method and three-dimensional force detection system

Abstract

The invention relates to a passive and wireless three-dimensional force sensor preparation method and a three-dimensional force detection system, and belongs to the technical field of sensors. Comprising the following steps: drawing n antenna patterns with different structures; according to the antenna pattern, the flexible film attached with the electrode material is made into an antenna, and a resonant antenna layer is obtained; wherein n is an integer greater than or equal to 3; selecting a thin film, and carving the appearance of the thin film to obtain a reflecting layer; selecting a flexible material, and preparing an elastic layer by using the flexible material; and combining the reflecting layer, the elastic layer and the resonant antenna layer to obtain the wireless passive three-dimensional force sensor. Acquiring phase information output by the three-dimensional force sensor by using a signal reading circuit; and the upper computer receives and analyzes the phase information, and identifies and obtains three-dimensional force information. Connection with a wire is not needed, and the problems of complex circuit and inconvenient power supply are avoided. Meanwhile, the method does not depend on a large instrument, real-time performance is achieved, and the sampling rate and the detection speed are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of sensors, and in particular to a preparation method for a passive wireless three-dimensional force sensor and a three-dimensional force detection system. Background Art

[0002] With the continuous emergence of flexible electronic products, artificial tactile sensing technology has emerged, covering many fields such as soft electrodes, flexible sensors, and wearable devices. In these cutting-edge electronic devices, flexible pressure sensors play a key role in simultaneously detecting normal loads and tangential loads on the sensor surface.

[0003] Currently, a variety of sensing principles are used to detect three-dimensional loads, including voltage, resistance, capacitance, and optical technologies. Among them, the resistive three-dimensional force sensor is one of the most commonly used methods, which is mainly composed of conductive sensing elements such as conductive rubber or metal. Its working principle is: when the sensor is subjected to an external force, the built-in conductive unit is compressed or stretched, resulting in a corresponding change in local resistance. In recent years, the research on flexible three-dimensional force sensors has attracted much attention from scientific researchers. For example, a capacitive three-dimensional force sensor was developed using a truncated PDMS pyramid array as a medium; there was also research that introduced a double-layer pore / PDMS composite medium into the sensor, and the shear force was represented by the ratio of the differential capacitance to the total capacitance, while the normal force corresponded to the change in the total capacitance; in addition, a capacitive three-dimensional force sensor was prepared by using a conductive fabric electrode and a porous elastomer material similar to a four-leaf clover pattern. However, the above three-dimensional force sensors generally have a problem: they all need to be connected to a signal conditioning circuit through wires to achieve signal transmission and energy supply. This method not only has complex wiring but also inconvenient power supply, seriously limiting its application in some extreme environments.

[0004] The pressure sensor based on resonance technology provides a new solution. This sensor can collect force information wirelessly through near-field electromagnetic coupling, and obtain the resonance frequency of the sensor by scanning the spectral characteristics of an external reading coil. However, this frequency scanning method usually relies on large instruments such as network analyzers, which not only have a large device volume but also poor real-time performance and low sampling rate, making it difficult to meet the requirements of rapid detection. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the complexity of the circuit caused by the need for wire connection and the inconvenience of power supply in the prior art, as well as the large device volume, poor real-time performance, low sampling rate, and slow detection speed caused by relying on large instruments.

[0006] In a first aspect, to solve the above technical problem, the present invention provides a preparation method for a passive wireless three-dimensional force sensor, including:

[0007] Draw n antenna patterns with different structures; according to the antenna patterns, make a flexible thin film attached with an electrode material into an antenna to obtain a resonant antenna layer; where n is an integer greater than or equal to 3;

[0008] Select a thin film, engrave the outer shape of the thin film to obtain a reflective layer;

[0009] Select a flexible material and prepare an elastic layer using the flexible material;

[0010] Combine the reflective layer, the elastic layer and the resonant antenna layer to obtain a wireless passive three-dimensional force sensor.

[0011] In an embodiment of the present invention, the combination method of the reflective layer, the elastic layer and the resonant antenna layer includes: the reflective layer, the elastic layer and the resonant antenna layer are stacked in sequence; or, both the reflective layer and the resonant antenna layer are embedded in the elastic layer.

[0012] In an embodiment of the present invention, the steps of sequentially stacking the reflective layer, the elastic layer and the resonant antenna layer are: place the resonant antenna layer in a mold and fix it with tape; pour the solution for preparing the elastic layer into the mold and scrape the surface flat; place the reflective layer on the scraped surface and wait for the solution to solidify; remove the mold;

[0013] The steps of embedding both the reflective layer and the resonant antenna layer into the elastic layer are: pour the solution for preparing the elastic layer into a first mold, and place the resonant antenna layer on the upper surface after the solution solidifies; place a second mold above the resonant antenna layer, pour the solution into the second mold and scrape the surface flat, and place the reflective layer on the upper surface after the solution solidifies; pour the solution into a third mold and press it flat, and remove the first mold, the second mold and the third mold after the solution solidifies.

[0014] In an embodiment of the present invention, the flexible thin film attached with an electrode material includes an electrode layer and a flexible thin film layer; the electrode layer is attached to one side or both sides of the flexible thin film layer.

[0015] In an embodiment of the present invention, the method for the elastic layer to obtain a porous structure includes a foaming method or a templating method.

[0016] Second, to solve the above technical problems, the present invention provides a passive wireless three-dimensional force detection system, including:

[0017] A signal reading circuit for connecting to an external power supply;

[0018] The three-dimensional force sensor prepared by the above method, the three-dimensional force sensor includes an inductance coil, and the inductance coil is coupled with the coupling coil of the signal reading circuit through electromagnetic induction;

[0019] A host computer, wirelessly connected to the signal reading circuit.

[0020] In an embodiment of the present invention, the signal reading circuit includes:

[0021] A voltage stabilizing module, connected to the external power supply, for controlling the voltage of the external power supply;

[0022] A signal generator module, connected to the voltage stabilizing module and the coupling coil;

[0023] A phase detection module, connected to the voltage stabilizing module and the coupling coil;

[0024] A differential amplification module, connected to the voltage stabilizing module and the phase detection module;

[0025] An interaction module, connected to the voltage stabilizing module, the differential amplification module and the signal generator module.

[0026] In an embodiment of the present invention, the interaction module of the signal reading circuit includes a small system module and a Bluetooth module that communicate with each other; the Bluetooth module receives the sampled voltage signal sent by the small system module and transmits the sampled voltage signal to the host computer.

[0027] In a third aspect, to solve the above technical problems, the present invention provides a resonant passive wireless three-dimensional force detection method, including:

[0028] Using the signal reading circuit in the above three-dimensional force detection system to obtain the phase information output by the three-dimensional force sensor prepared by the above method at different excitation frequencies, and transmitting the phase information to the host computer;

[0029] The host computer analyzes the phase information to identify and obtain three-dimensional force information.

[0030] In a fourth aspect, to solve the above technical problems, the present invention provides an electronic device, including the above passive wireless three-dimensional force detection system.

[0031] The above technical solutions of the present invention have the following beneficial effects compared with the prior art:

[0032] (1) A method for fabricating a passive wireless three-dimensional force sensor and a three-dimensional force detection system according to the present invention can detect force signals of different frequencies or modes by designing antenna patterns with different structures, increasing the versatility of the sensor and enabling it to flexibly adapt to various detection requirements. Utilizing the high-sensitivity response of the resonant antenna layer to minute force changes, the sensor of the present invention not only improves the detection accuracy but also exhibits excellent real-time performance. This effectively solves the common problems of complex circuitry and inconvenient power supply in traditional sensors, providing users with a more convenient and reliable detection solution. In addition, the present invention uses a flexible film attached with electrode materials, which can be used on curved or deformed surfaces, expanding its application range. By introducing the film design, the weight of the entire sensor is kept at a low level, facilitating integration into portable devices and improving the portability of the devices.

[0033] (2) The three-dimensional force sensor fabricated by the method of the present invention does not require connecting wires, avoiding complex circuitry and inconvenient power supply. At the same time, during the three-dimensional force detection process, the coil of the reading antenna does not need to be connected to large instruments, not only achieving good real-time performance but also reaching a high sampling rate and detection speed.

[0034] (3) The present invention realizes resonant passive wireless three-dimensional force detection through a signal reading circuit, a three-dimensional force sensor, and a host computer. This design not only solves the difficulties in wiring and inconvenient power supply of flexible three-dimensional force sensors but also addresses the problems of poor real-time performance and low sampling rate caused by the frequency sweeping method commonly used in resonant frequency detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to make the content of the present invention easier to be clearly understood, the following further details the present invention according to specific embodiments of the present invention in conjunction with the drawings, where

[0036] Figure 1 is a flowchart of a method for fabricating a passive wireless three-dimensional force sensor in a preferred embodiment of the present invention;

[0037] Figure 2 is a 3D structure diagram of the sensor fabricated by the method for fabricating a passive wireless three-dimensional force sensor in a preferred embodiment of the present invention;

[0038] Figure 3 is a schematic structural diagram of a three-dimensional force sensor combination in a preferred embodiment of the present invention;

[0039] Figure 4 is a flowchart for fabricating a stacked structure three-dimensional force sensor in a preferred embodiment of the present invention;

[0040] Figure 5 is a flowchart for fabricating an embedded structure three-dimensional force sensor in a preferred embodiment of the present invention;

[0041] Figure 6 Schematic diagram of the equivalent model of the three-dimensional force sensor measurement system in the preferred embodiment of the present invention;

[0042] Figure 7 Phase-frequency diagram of the LC sensor in the preferred embodiment of the present invention;

[0043] Figure 8 Phase-frequency diagram of the coil with forces applied in different directions in the preferred embodiment of the present invention;

[0044] Figure 9 Structural diagram of a passive wireless three-dimensional force detection system in the preferred embodiment of the present invention.

[0045] Explanation of the reference numerals in the drawings of the specification: 1. Reflection layer; 2. Elastic layer; 3. Metal layer; 4. Flexible film substrate. Detailed implementation manners

[0046] The present invention will be further described below in conjunction with the drawings and specific embodiments, so that those skilled in the art can better understand the present invention and be able to implement it, but the embodiments given are not intended to limit the present invention.

[0047] Embodiment 1

[0048] Referring to Figure 1 and Figure 2 As shown, the embodiment of the present invention provides a method for fabricating a passive wireless three-dimensional force sensor, including:

[0049] Drawing n antenna patterns with different structures; according to the antenna patterns, making a flexible film with an electrode material into an antenna to obtain a resonant antenna layer; where n is an integer greater than or equal to 3;

[0050] Selecting a film and engraving the outer shape of the film to obtain the reflection layer 1;

[0051] Selecting a flexible material and preparing the elastic layer 2 using the flexible material;

[0052] Combining the reflection layer 1, the elastic layer 2 and the resonant antenna layer to obtain a passive wireless three-dimensional force sensor.

[0053] An embodiment of the present invention provides a method for fabricating a passive wireless three-dimensional force sensor. By designing antenna patterns with different structures, the sensor can detect force signals of different frequencies or modes, increasing the versatility of the sensor and enabling it to flexibly adapt to various detection requirements. The resonant antenna layer is utilized to respond to minute force changes, thereby improving the sensitivity of the sensor and featuring good real-time performance, effectively avoiding the complexity of traditional sensor circuits and the inconvenience of power supply. In addition, a flexible thin film with electrode material attached is adopted, enabling it to be used on curved or deformed surfaces and expanding its application scope. By introducing the thin film design, the weight of the entire sensor is maintained at a low level, facilitating integration into portable devices and enhancing the portability of the devices. The elastic layer 2 can adaptively adjust according to external pressure or deformation, ensuring stable performance of the sensor under different working conditions. Therefore, the sensor fabricated by the method described in the embodiment of the present invention does not require connection of wires, avoiding the complexity of circuits and the inconvenience of power supply. Meanwhile, during the three-dimensional force detection process, the coil of the reading antenna does not need to be connected to large-scale instruments, not only achieving good real-time performance but also reaching a high sampling rate and detection speed.

[0054] Specifically, for the structure of the three-dimensional force sensor, refer to Figure 2 , which includes a reflective layer 1, an elastic layer 2, and a resonant antenna layer (referred to as the antenna layer for short). Among them, the reflective layer 1 is a thin film material located at the top layer, having the characteristics of reflecting or absorbing electromagnetic waves, such as a metal thin film or a magnetic thin film, etc. The middle elastic layer 2 is composed of deformable elastic materials, such as silicone materials like PDMS and Ecoflex, for sensing the deformation under external force. The bottom layer is the resonant antenna layer, which includes n resonant antennas with different structures and is made into a flexible film substrate 4 using a flexible thin film with electrode material attached. In this embodiment, the value of n is 4. These resonant antennas can be LC resonant antennas composed of a planar spiral inductor coil and a capacitor structure, or microwave microstrip antennas. It is only required that the resonant frequencies of each antenna are within a similar frequency range and are different from each other.

[0055] Furthermore, there are multiple options for the combination mode of the upper reflective layer 1, the bottom antenna layer, and the middle elastic layer 2. Specifically, they can be assembled in a stacked manner of three layers in sequence, or the upper and lower layers can be embedded in the elastic layer 2. These two different combination modes are respectively as shown in Figure 3 (a) and Figure 3 (b). This diverse structural design not only provides flexibility for optimizing the performance of the sensor but also can meet the requirements of different application scenarios.

[0056] Specifically, for the antenna layer, the specific manufacturing steps are as follows: First, use AutoCAD software to draw the antenna pattern. Select a flexible film (such as polyimide film, PET, etc.) attached with electrode materials (such as copper, silver, etc.), and process it using standard screen printing and etching techniques to produce the designed antenna pattern. The flexible film attached with electrode materials includes an electrode layer and a flexible film layer. The thickness range of the electrode layer is 1 - 12 μm, and the thickness of the flexible film layer is between 10 - 50 μm. The electrode layer can be attached to one or both sides of the flexible film, depending on the design requirements. If double-sided electrodes are used and connection is required, through-hole perfusion technology is used for processing. It should be noted that since the material of the electrode layer is metal, the electrode layer can also be referred to as metal layer 3.

[0057] Specifically, the main function of the reflective layer 1 is to reflect or absorb electromagnetic waves, and its material can be selected from commercial metals (such as aluminum, copper, etc.) or wave-absorbing materials. To ensure the flexibility and overall performance of the sensor, the thickness of the reflective layer 1 is usually controlled at about 50 μm. The shape of the reflective layer 1 can be designed and engraved through lithography technology, and its area does not need to completely cover the underlying resonant antenna layer to achieve the best electromagnetic compatibility and structural compactness.

[0058] Specifically, for the elastic layer 2, a soft elastic material can be used, such as silicone materials like polydimethylsiloxane (PDMS). Its preparation method is to mix two liquid components of the silicone material (component A is the monomer, component B is the curing agent) in a certain proportion, and then let it stand at room temperature for a period of time (such as 24 hours) to cure into a solid elastic material.

[0059] Furthermore, to ensure the sensitivity of the sensor, the elastic layer 2 can be prepared with a porous structure in the flexible material, thereby reducing the modulus of the elastic material and improving the sensitivity. The methods for preparing the porous structure include the foaming method and the template method. The following takes the preparation of elastomeric PDMS by the foaming method as an example for illustration:

[0060] First, mix sodium dodecyl sulfate (SDS) and deionized water (DI) in a mass ratio of 1:1 to 1:100 (SDS:DI), and then shake it in a vortex oscillator to form an SDS / DI (abbreviated as SD) mixture. Then, add this mixture to both part A and part B of the PDMS respectively. The specific operation is to add the SD mixture to part A and part B of the PDMS in a mass ratio of 1:1, and manually stir each solution for 5 minutes. After that, mix the two solutions in a mass ratio of 1:1 in a beaker and continue to stir for 5 minutes to evenly disperse the deionized water in the mixture. Finally, place the mixture of SD, part A, and part B, called the PDMS solution, in a vacuum chamber and evacuate it for 15 minutes to remove the bubbles.

[0061] Further, the antenna layer, the reflective layer 1, and the elastic layer 2 prepared by the above method are used to assemble the sensor. For Figure 3 the stacked structure shown in (a), the specific assembly method is as follows: First, place the lower antenna layer in the mold and fix it with tape (as shown in Figure 4 (a)). Second, pour the prepared PDMS solution into the mold (as shown in Figure 4 (b)), and scrape the surface flat with a scraper (as shown in Figure 4 (c)). Then, place the upper reflective layer 1 on top of the PDMS solution (as shown in Figure 4 (d)). Next, place the entire mold on a heating table for heating until the PDMS solution is completely cured (as shown in Figure 4 (e)). After curing, carefully remove the sensor from the mold to obtain a three-dimensional force sensor with a stacked structure (as shown in Figure 4 (f)). In this assembly, the mold is an open box structure, and its specific dimensions can be flexibly adjusted and customized according to actual application requirements.

[0062] For Figure 3 the embedded structure shown in (b), the specific assembly method is as follows: First, pour the above PDMS solution into the first mold (the mold is as shown in Figure 5 (a)) and cure it (as shown in Figure 5 (b)). After curing, place the bottom antenna layer on the upper surface of the PDMS cured layer (as shown in Figure 5 (c)). Then, place the second mold on it, pour the PDMS solution and flatten it (as shown in Figure 5 (d)). After this layer of PDMS is cured, place the top reflective layer 1 on the upper surface (as shown in Figure 5 (e)). Subsequently, place the third mold on it (as shown in Figure 5 (f)), pour the PDMS solution and flatten it (as shown in Figure 5 (g)). Finally, after the PDMS is completely cured (as shown in Figure 5 (h)), carefully remove all the molds (all the molds include the first mold, the second mold, and the third mold) to complete the preparation of the three-dimensional force sensor and obtain the sensor with an embedded structure (as shown in Figure 5 (i)). In this assembly, the first mold is an open box structure, the second mold and the third mold are upper and lower open mold frames, and the specific dimensions of each mold can be flexibly adjusted and customized according to actual application requirements.

[0063] For the above-mentioned stacked structure, its functional layers (antenna layer, elastic layer 2, and reflection layer 1) are clearly defined in the stacked structure, facilitating subsequent debugging and optimization. For the embedded structure, each layer is completely wrapped by PDMS, which not only enhances the mechanical strength and durability of the sensor but also reduces the risk of interlayer separation. In practical applications, the appropriate structural design can be flexibly selected according to specific requirements.

[0064] Specifically, the working principle of the resonant three-dimensional force sensor prepared by the method of this embodiment is as follows: The sensor requires an external reading antenna to obtain the information of the sensor, and the reading antenna is connected to an external circuit. This design enables the three-dimensional force sensor to transfer information and energy to the external circuit through electromagnetic coupling without wire connection. Taking the LC resonant three-dimensional force sensor as an example, the equivalent model of its measurement system is as Figure 6 shown. The four LC resonant antennas in the sensor respectively correspond to four different resonant frequencies. Among them, R 0 and L 0 are the equivalent resistance and inductance of the reading coil, while R 1 ~R 4 、L 1 ~L 4 and C 1 ~C 4 are the equivalent resistance, inductance, and parasitic capacitance of the four LC resonant antennas respectively. Since the structures of these four LC resonant antennas are different, their resonant frequencies are also different. When an external force is applied to the sensor, the middle elastic layer 2 deforms. This deformation causes the distance between the upper reflection layer 1 and the lower antenna layer to decrease, thereby causing a change in the magnetic field around the antenna. This change in the magnetic field ultimately leads to a change in the resonant frequency of the sensor. Among them, the mathematical expression of the resonant frequency f s of the s-th sensor is:

[0065]

[0066] where, π is the pi, L s is the inductance of the s-th LC resonant antenna, and C s is the parasitic capacitance of the s-th LC resonant antenna.

[0067] Furthermore, according to the transformer principle, the phase loss reaches the maximum value at the resonant frequency. Therefore, the resonant frequency can be accurately detected by scanning the phase change at different frequencies and finding the minimum value of the phase. The specific steps are as follows:

[0068] First, perform a frequency sweep test on the sensor. During the test, connect the reading coil to the network analyzer and set it to the frequency sweep mode. As Figure 7 shown, the four resonant frequency drop points f 1, f 2 , f 3 and f 4 , respectively corresponding to four resonant antennas in the sensor. When a three-dimensional force is applied to the sensor, the four resonant frequencies will all change. However, since the change in the resonant frequency is small and the frequency changes of each resonant antenna do not interfere with each other, there will be no crosstalk phenomenon.

[0069] Secondly, apply three-dimensional forces in different directions to the sensor. When applying the force, the phase-frequency curve of the coil is as Figure 8 shown, where the continuous curve (corresponding to Figure 8 , the first curve from top to bottom) represents the initial state of the sensor. When the sensor is subjected to a normal force in the -Z direction, the distance between the ferrite film and the coil decreases, resulting in a decrease in the resonant frequency (corresponding to Figure 8 , the second curve from top to bottom). When the sensor is subjected to a tangential force in the -X direction, the facing area between the ferrite film and the coil increases, and the resonant frequency also decreases (corresponding to Figure 8 , the third curve from top to bottom). On the contrary, when the sensor is subjected to a tangential force in the +X direction, the facing area between the ferrite film and the coil decreases, and the resonant frequency increases (corresponding to Figure 8 , the fourth curve from top to bottom). When the excitation frequency is set to 8.5 MHz, measure the phase change of the coil: the tangential force in the -X direction and the normal force in the -Z direction will both cause the phase of the coil to decrease, while the tangential force in the +X direction will cause the phase of the coil to increase. Thus, it can be seen that three-dimensional forces in different directions will cause different changes in the phases of the four LC resonant antennas of the sensor. Therefore, the information of three-dimensional forces can be identified and distinguished by the phase changes of the four resonant antennas at a specific excitation frequency.

[0070] Embodiment 2

[0071] This embodiment provides a passive wireless three-dimensional force detection system, including:

[0072] A signal reading circuit for connecting to an external power supply;

[0073] The three-dimensional force sensor prepared by the method of Embodiment 1, and the three-dimensional force sensor includes an inductance coil, and the inductance coil is coupled with the coupling coil of the signal reading circuit through electromagnetic induction;

[0074] An upper computer, wirelessly connected to the signal reading circuit.

[0075] A passive wireless three-dimensional force detection system provided in this embodiment realizes resonant passive wireless three-dimensional force detection through a signal reading circuit, a three-dimensional force sensor, and a host computer. This embodiment not only solves the problems of difficult wiring and inconvenient power supply in flexible three-dimensional force sensors, but also solves the problems of poor real-time performance and low sampling rate in the frequency sweeping method commonly used in resonant frequency detection. This system design avoids the common problems of complex circuits and power supply in traditional sensors, and at the same time provides a solution for reading the data of antenna coils without connecting to large instruments, which not only ensures the real-time performance of the detection process, but also enables the sensor to achieve high sampling rate and fast detection response.

[0076] Specifically, for the three-dimensional force sensor prepared by the method described in Embodiment 1, its specific working principle can refer to the relevant description in Embodiment 1.

[0077] Specifically, the three-dimensional force sensor provided in this embodiment internally includes four resonant antennas, and each antenna corresponds to a unique resonant frequency. Therefore, during the measurement process, four excitation frequencies need to be set separately, and the corresponding phase outputs are obtained. To achieve this function, this embodiment designs a signal reading circuit specifically for the three-dimensional force sensor. The system block diagram of this signal reading circuit is as Figure 9 shown, and mainly includes the following modules: an interaction module, a voltage stabilization module, a signal generator module, a phase detection module, and a differential amplification module. Among them, the interaction module includes a small system module and a Bluetooth module.

[0078] Further, referring to Figure 9 , the connection relationships of each module are as follows: The voltage stabilization module is connected to an external power supply for controlling the voltage of the external power supply; the signal generator module is connected to the voltage stabilization module and the coupling coil; the phase detection module is connected to the voltage stabilization module and the coupling coil; the differential amplification module is connected to the voltage stabilization module and the phase detection module; the interaction module is connected to the voltage stabilization module, the differential amplification module, and the signal generator module.

[0079] Further, the working principle (or specific steps) of the signal reading circuit is as follows:

[0080] Step 1: The voltage stabilization module is connected to an external power supply and is responsible for stabilizing the input voltage to the voltage values suitable for the interaction module, the signal generator module, the phase detection module, and the differential amplification module respectively.

[0081] Step 2: After the power is turned on, the microcontroller of the small system module generates four excitation frequencies corresponding to the resonant antennas through the control chip respectively.

[0082] Step 3: These excitation signals are sent to the external coupling coil of the LC 3D force sensor. After passing through the external coupling coil of the LC 3D force sensor, the chip in the phase detection module converts the phase information of the coupling coil into a voltage signal.

[0083] Step 4: The converted voltage signal is amplified by the differential amplification module, and the amplification factor is determined by the difference at the input end, thereby improving the signal-to-noise ratio and stability of the signal.

[0084] Step 5: The amplified signal is sampled by the single-chip microcomputer in the small system module, and the sampled value is transmitted to the host computer through the Bluetooth module, completing the acquisition and transmission of data.

[0085] In Step 1, the voltage division design not only avoids the problems of power conflict and voltage mismatch, but also improves the stability and reliability of the circuit. Step 2 ensures the frequency accuracy and stability of the excitation signal, providing a high-quality input signal for subsequent phase detection. This two-stage signal processing method in Steps 3 and 4 not only improves the signal-to-noise ratio of the signal, but also ensures the stability of the signal during transmission, avoiding measurement errors caused by signal attenuation or interference. Step 5 ensures the high precision and high resolution of data acquisition. At the same time, the selection of wireless transmission mode increases the flexibility of the system and ensures the reliability of data transmission. The addition of the Bluetooth module enables the circuit to communicate with mobile devices or remote terminals conveniently, expanding the application scenarios. Through this modular design concept in this embodiment, each module (such as the power supply voltage stabilization module, signal generator module, phase detection module, etc.) can be independently developed and tested, facilitating the integration of the system and subsequent expansion.

[0086] To more clearly illustrate the signal reading circuit provided in this embodiment, the following is a detailed description through specific examples.

[0087] Exemplarily, the power supply voltage stabilization module uses the AMS1117 chip to regulate the input 5V voltage to 3.3V. Among them, 3.3V is used to supply power to the interaction module, while 5V provides power for the chips in the signal generator module, the chips in the phase detection module, and the chips in the differential amplification module. In this embodiment, the microcontroller of the small system module selects STM32F103C8T6, and four excitation frequencies corresponding to the resonant antenna are generated respectively by controlling the AD9851 chip. After these excitation signals pass through the external coupling coil of the LC 3D force sensor, the AD8302 phase detection chip converts the phase information of the coupling coil into a voltage signal. Subsequently, this voltage signal is amplified by the INA333 low-power differential amplifier, and the amplification factor is determined by the difference at the input end. The amplified signal is sampled by the built-in ADC of the STM32 single-chip microcomputer, and finally the sampled value is transmitted to the host computer through the Bluetooth module.

[0088] Embodiment III

[0089] Based on the same inventive concept, this embodiment provides a resonant passive wireless three-dimensional force detection method. The principle of solving the problem is similar to that of a passive wireless three-dimensional force detection system provided in Embodiment II, and the repeated parts will not be elaborated here.

[0090] This embodiment provides a resonant passive wireless three-dimensional force detection method, including:

[0091] Using the signal reading circuit provided in Embodiment II to obtain the phase information output by the three-dimensional force sensor prepared by the method described in Embodiment I at different excitation frequencies, and transmitting the phase information to the host computer;

[0092] The host computer analyzes the phase information to identify and obtain three-dimensional force information.

[0093] Embodiment IV

[0094] This embodiment provides an electronic device, including a passive wireless three-dimensional force detection system provided in Embodiment II.

[0095] Those skilled in the art should understand that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0096] The present application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, and the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0097] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device, and the instruction device implements the functions in the process Figure 1One process or multiple processes and / or boxes Figure 1 The functions specified in one box or multiple boxes.

[0098] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process. Thus, the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one process Figure 1 One process or multiple processes and / or boxes Figure 1 The steps of the functions specified in one box or multiple boxes.

[0099] Obviously, the above embodiments are only examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A method for preparing a passive wireless three-dimensional force sensor, characterized in that: include: Draw antenna patterns of n different structures; According to the antenna pattern, a flexible film with an electrode material is made into an antenna to obtain a resonant antenna layer; Wherein n is an integer greater than or equal to 3; Selecting a film, and engraving the outer shape of the film to obtain a reflective layer; selecting a flexible material, and preparing an elastic layer using the flexible material; The reflective layer, the elastic layer and the resonant antenna layer are combined to obtain a wireless passive three-dimensional force sensor.

2. The method for preparing a passive wireless three-dimensional force sensor according to claim 1, characterized in that: The combination of the reflective layer, the elastic layer and the resonant antenna layer includes: the reflective layer, the elastic layer and the resonant antenna layer are stacked in sequence; or the reflective layer and the resonant antenna layer are both embedded in the elastic layer.

3. The method for preparing a passive wireless three-dimensional force sensor according to claim 2, characterized in that: The steps of stacking the reflective layer, the elastic layer and the resonant antenna layer in sequence are: placing the resonant antenna layer in a mold and fixing it with tape; pouring a solution for preparing the elastic layer into the mold and flattening the surface; placing the reflective layer on the flattened surface and waiting for the solution to solidify; removing the mold; The steps of embedding both the reflective layer and the resonant antenna layer into the elastic layer are as follows: pouring a solution for preparing the elastic layer into a first mold, and placing the resonant antenna layer on the upper surface after the solution is solidified; Placing a second mold above the resonant antenna layer, pouring the solution into the second mold, and flattening the surface, and placing the reflective layer on the upper surface after the solution solidifies; The third mold is placed above the reflective layer, the solution is poured into the third mold and flattened, and the first mold, the second mold and the third mold are removed after the solution is solidified.

4. The method for preparing a passive wireless three-dimensional force sensor according to claim 1, characterized in that: The flexible film with electrode material includes an electrode layer and a flexible film layer; the electrode layer is attached to one side or both sides of the flexible film layer.

5. The method for preparing a passive wireless three-dimensional force sensor according to claim 1, characterized in that: The method for obtaining the porous structure of the elastic layer includes a foaming method or a template method.

6. A passive wireless three-dimensional force detection system, characterized in that: include: A signal reading circuit, used for connecting to an external power supply; A three-dimensional force sensor prepared by the method according to any one of claims 1 to 5, wherein the three-dimensional force sensor comprises an inductor coil, and the inductor coil is coupled to the coupling coil of the signal reading circuit by electromagnetic induction; The host computer is wirelessly connected to the signal reading circuit.

7. A passive wireless three-dimensional force detection system according to claim 6, characterized in that: The signal reading circuit comprises: A voltage stabilizing module, connected to the external power supply, and used to control the voltage of the external power supply; A signal generator module connected to the voltage stabilizing module and the coupling coil; A phase detection module connected to the voltage stabilization module and the coupling coil; A differential amplification module, connected to the voltage stabilization module and the phase detection module; The interaction module is connected with the voltage stabilization module, the differential amplifier module and the signal generator module.

8. A passive wireless three-dimensional force detection system according to claim 6 or 7, characterized in that: The interactive module of the signal reading circuit includes a small system module and a Bluetooth module that communicate with each other; the Bluetooth module receives the sampled voltage signal sent by the small system module, and transmits the sampled voltage signal to the host computer.

9. A resonant passive wireless three-dimensional force detection method, characterized in that: include: Using a signal reading circuit in a three-dimensional force detection system as described in any one of claims 6 to 8 to obtain phase information output by a three-dimensional force sensor prepared by the method as described in any one of claims 1 to 5 at different excitation frequencies, and transmitting the phase information to a host computer; The host computer analyzes the phase information and identifies and obtains three-dimensional force information.

10. An electronic device, characterized in that: It comprises a passive wireless three-dimensional force detection system as described in any one of claims 6 to 8.

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