A flexible capacitive pressure sensor using frequency modulation signal
By introducing frequency modulated signals and RLC resonant circuits into flexible capacitive pressure sensors, the problem of poor sensor stability and consistency is solved, and a high integration and low cost monitoring effect is achieved, which is suitable for the detection of human joint activity status.
Patent Information
- Application Number
- CN202210848344.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-07-19
- Publication Date
- 2024-12-10
- Estimated Expiration
- 2042-07-19
AI Technical Summary
The existing flexible capacitive pressure sensors have problems such as poor stability and consistency, low integration and high cost, especially being disturbed by stray capacitors and coupling capacitors, and interference introduced by signal conductors is difficult to avoid.
Flexible capacitive pressure sensor using frequency modulation signals, by introducing RLC resonance circuit into flexible compressible capacitors with shielding layer, converting capacitance changes into frequency changes, and using the signal acquisition module to collect and send frequency signals in real time to avoid miscellaneous Interference between discharge capacitors and coupling capacitors.
It effectively improves the stability and consistency of the sensor, enhances integration, reduces costs, avoids interference introduced by signal conductors, and is suitable for monitoring human joint activity.
Smart Images
Figure CN115165162B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a flexible capacitive pressure sensor, in particular to a flexible capacitive pressure sensor using a frequency modulation signal. Background Art
[0002] Flexible capacitive pressure sensor is a flexible electronic device that can convert pressure into capacitance changes. It can be used to monitor the activity status of human joints and has wide applications in rehabilitation medicine and other fields.
[0003] At present, there are three main types of flexible capacitive pressure sensors: the first type is a flexible capacitive pressure sensor without a shielding layer. On the one hand, this type of sensor will be interfered by the stray capacitance and coupling capacitance in the free space, and on the other hand, it will be interfered by the stray capacitance and coupling capacitance introduced by the signal wire, so it has problems with poor stability and consistency. The second type is a flexible capacitive pressure sensor with a shielding layer. This type of sensor can avoid the interference of stray capacitance and coupling capacitance in the free space, but it will be interfered by the stray capacitance and coupling capacitance introduced by the signal wire, so it also has problems with poor stability and consistency. The third type is a flexible capacitive pressure sensor with a shielding layer and extremely short signal wires. This type of sensor can avoid the interference of stray capacitance and coupling capacitance (it can avoid the interference of stray capacitance and coupling capacitance in the free space, and it can also avoid the interference of stray capacitance and coupling capacitance introduced by the signal wire), but it has problems of low integration and high cost.
[0004] Research shows that the transmission of biological sensory nerve signals will not be interfered by the external electromagnetic environment, and has the advantages of strong anti-interference ability and low energy consumption. The principle is that biological signals are a kind of frequency modulated signals, and frequency modulated signals have strong anti-interference and anti-fading capabilities during transmission.
[0005] Therefore, inspired by biological sensory nerve signals, the invention of a flexible capacitive pressure sensor that uses frequency modulation signals is bound to solve the problems of poor stability and consistency, low integration and high cost of existing flexible capacitive pressure sensors. Summary of the invention
[0006] In order to solve the problems of poor stability and consistency, low integration and high cost of existing flexible capacitive pressure sensors, the present invention provides a flexible capacitive pressure sensor using a frequency modulation signal.
[0007] The present invention is achieved by adopting the following technical solutions:
[0008] A flexible capacitive pressure sensor using a frequency modulated signal includes a flexible compressible capacitor with a shielding layer, an inductor, three signal wires, two shielding wires, and a signal acquisition module;
[0009] The flexible compressible capacitor with a shielding layer comprises a flexible compressible dielectric layer, two flexible electrode layers, two flexible dielectric layers, and two flexible shielding layers; the flexible compressible dielectric layer is sandwiched between the two flexible electrode layers; the flexible compressible dielectric layer and the two flexible electrode layers are both sandwiched between the two flexible dielectric layers; the flexible compressible dielectric layer, the two flexible electrode layers, and the two flexible dielectric layers are all sandwiched between the two flexible shielding layers;
[0010] The first flexible electrode layer is electrically connected to the signal acquisition module through the first signal wire, the inductor, and the second signal wire in sequence; the second flexible electrode layer is electrically connected to the signal acquisition module through the third signal wire; and the two flexible shielding layers are grounded through two shielding wires respectively.
[0011] The flexible compressible capacitor with a shielding layer is circular, with a diameter of 2mm~50mm; the thickness of the flexible compressible dielectric layer is 100μm~2000μm, and it is made of polydimethylsiloxane foam, and the pore size of the polydimethylsiloxane foam is 10μm~30μm; the thickness of the flexible electrode layer is 5μm~20μm, and it is made of a flexible conductive material; the thickness of the flexible dielectric layer is 200μm~2000μm, and it is made of polydimethylsiloxane; the thickness of the flexible shielding layer is 5μm~20μm, and it is made of a flexible conductive material.
[0012] The inductor is a 1206 chip inductor, and its inductance value is 1μH~1mH.
[0013] The signal wire is a copper wire covered with an insulating layer.
[0014] The shielded conductor is a copper conductor covered with an insulating layer.
[0015] The signal acquisition module includes a frequency data acquisition card and a 32-bit microcontroller; the first flexible electrode layer is electrically connected to the frequency data acquisition card through a first signal wire, an inductor, and a second signal wire in sequence; the second flexible electrode layer is electrically connected to the frequency data acquisition card through a third signal wire; and the frequency data acquisition card is electrically connected to the 32-bit microcontroller.
[0016] The preparation steps of the polydimethylsiloxane foam are as follows:
[0017] Step 1: mixing a polydimethylsiloxane prepolymer solution and a curing agent in a mass ratio of 10:1 to obtain a polydimethylsiloxane solution;
[0018] Step 2: Add sugar particles to the polydimethylsiloxane solution at a volume ratio of 10% to 60% and stir evenly to obtain a mixed solution;
[0019] Step 3: heating and curing the mixture at 60° C. for 6 h to obtain polydimethylsiloxane foam containing sugar;
[0020] Step 4: Put the polydimethylsiloxane foam containing sugar into 50° C. warm water to dissolve it, so as to obtain polydimethylsiloxane foam.
[0021] The preparation steps of the flexible conductive material are as follows:
[0022] Step 1: mixing a polydimethylsiloxane prepolymer solution and a curing agent in a mass ratio of 10:1 to obtain a polydimethylsiloxane solution;
[0023] Step 2: Adding conductive carbon black particles to the polydimethylsiloxane solution at a mass ratio of 1:10 and stirring evenly to obtain a mixed solution;
[0024] Step 3: Heat and cure the mixture at 60° C. for 6 hours to obtain a flexible conductive material.
[0025] When working, the flexible compressible capacitor with a shielding layer is attached to the surface of the human joint, and is connected in series with the inductor to form an RLC resonant circuit. The signal acquisition module is electrically connected to the host computer.
[0026] The specific working process is as follows: When the human joints are not moving, the shape of the flexible compressible capacitor with a shielding layer remains unchanged, its capacitance value remains unchanged, and the resonant frequency of the RLC resonant circuit remains unchanged. During this process, the signal acquisition module collects the resonant frequency of the RLC resonant circuit in real time, and sends the collected results to the host computer for display in real time. When the human joints move, the flexible compressible capacitor with a shielding layer is squeezed and compressed (the distance between the two flexible electrode layers decreases), its capacitance value increases, and the resonant frequency of the RLC resonant circuit shifts. During this process, the signal acquisition module collects the resonant frequency of the RLC resonant circuit in real time, and sends the collected results to the host computer for display in real time.
[0027] Based on the above process, compared with the existing flexible capacitive pressure sensor, the flexible capacitive pressure sensor using frequency modulation signal described in the present invention is inspired by biological sensory nerve signals (such as Figure 3As shown), an RLC resonant circuit is used to convert the capacitance amplitude modulation signal into a frequency modulation signal, which has the following beneficial effects: First, compared with the first existing flexible capacitive pressure sensor, the present invention can avoid the interference of stray capacitance and coupling capacitance in free space due to the shielding layer on the one hand, and can avoid the interference of stray capacitance and coupling capacitance introduced by the signal wire on the other hand due to the use of frequency modulation signal, thereby effectively improving the stability and consistency. Second, compared with the second existing flexible capacitive pressure sensor, the present invention can avoid the interference of stray capacitance and coupling capacitance introduced by the signal wire due to the use of frequency modulation signal, thereby also effectively improving the stability and consistency. Third, compared with the third existing flexible capacitive pressure sensor, the present invention can avoid the interference of stray capacitance and coupling capacitance introduced by the signal wire due to the use of frequency modulation signal, without shortening the signal wire, thereby effectively improving the integration and effectively reducing the cost.
[0028] In order to verify the above beneficial effects, the following comparative tests were conducted:
[0029] Comparative test 1:
[0030] The first existing flexible capacitive pressure sensor is compressed by 0%, 10%, 20%, 30%, and 40%, and its output signal (capacitance value) is recorded to obtain Figure 4 The compression-capacitance curve is shown in Figure 1. Figure 4 It can be seen from the error bars on the ordinate that the output signal of the first existing flexible capacitive pressure sensor is interfered by the stray capacitance and coupling capacitance in the free space on the one hand, and by the stray capacitance and coupling capacitance introduced by the signal wire on the other hand.
[0031] The present invention is compressed by 0%, 10%, 20%, 30%, and 40%, and its output signal (resonance frequency) is recorded to obtain Figure 5 The compression amount-resonance frequency curve shown. Figure 5 It can be seen from the error bars on the ordinate that the output signal of the present invention is not interfered by the stray capacitance and coupling capacitance in the free space, nor is it interfered by the stray capacitance and coupling capacitance introduced by the signal wire.
[0032] The conclusion is as follows: the present invention can avoid the interference of stray capacitance and coupling capacitance.
[0033] Comparative test 2:
[0034] The present invention is compressed by 0%, 10%, 20%, 30%, and 40%, and its output signal (resonance frequency) is recorded to obtain Figure 5 The compression amount-resonance frequency curve shown. Figure 5It can be seen from the error bars on the ordinate that the output signal of the present invention is not interfered by the stray capacitance and coupling capacitance in the free space, nor is it interfered by the stray capacitance and coupling capacitance introduced by the signal wire.
[0035] After removing the two flexible shielding layers in the present invention, the compression is performed by 0%, 10%, 20%, 30%, and 40%, and the output signal (resonance frequency) is recorded to obtain Figure 6 The compression amount-resonance frequency curve shown. Figure 6 It can be seen from the error bars on the ordinate that after the two flexible shielding layers in the present invention are removed, the output signal is interfered by the stray capacitance and coupling capacitance in the free space.
[0036] The present invention has a reasonable structure and ingenious design, and effectively solves the problems of poor stability and consistency, low integration and high cost of existing flexible capacitive pressure sensors, and is suitable for monitoring the activity status of human joints. BRIEF DESCRIPTION OF THE DRAWINGS
[0037] Figure 1 It is a structural schematic diagram of the present invention.
[0038] Figure 2 yes Figure 1 Top view of the .
[0039] Figure 3 Schematic diagram of the present invention inspired by biological sensory nerve signals.
[0040] Figure 4 This is the compression-capacitance curve of the first existing flexible capacitive pressure sensor in comparative experiment 1.
[0041] Figure 5 It is the compression amount-resonance frequency curve of the present invention in comparative test 1 and comparative test 2.
[0042] Figure 6 It is a compression amount-resonance frequency curve of the present invention after removing the two flexible shielding layers in the comparative experiment 2.
[0043] In the figure: 101 - flexible compressible dielectric layer, 102 - flexible electrode layer, 103 - flexible dielectric layer, 104 - flexible shielding layer, 2 - inductor, 3 - signal wire, 4 - shielding wire, 5 - signal acquisition module. DETAILED DESCRIPTION
[0044] Embodiment 1
[0045] A flexible capacitive pressure sensor using a frequency modulated signal, comprising a flexible compressible capacitor with a shielding layer, an inductor 2, three signal wires 3, two shielding wires 4, and a signal acquisition module 5;
[0046] The flexible compressible capacitor with a shielding layer comprises a flexible compressible dielectric layer 101, two flexible electrode layers 102, two flexible dielectric layers 103, and two flexible shielding layers 104; the flexible compressible dielectric layer 101 is sandwiched between the two flexible electrode layers 102; the flexible compressible dielectric layer 101 and the two flexible electrode layers 102 are both sandwiched between the two flexible dielectric layers 103; the flexible compressible dielectric layer 101, the two flexible electrode layers 102, and the two flexible dielectric layers 103 are both sandwiched between the two flexible shielding layers 104;
[0047] The first flexible electrode layer 102 is electrically connected to the signal acquisition module 5 through the first signal wire 3, the inductor 2, and the second signal wire 3 in sequence; the second flexible electrode layer 102 is electrically connected to the signal acquisition module 5 through the third signal wire 3; the two flexible shielding layers 104 are grounded through two shielding wires 4 respectively.
[0048] The flexible compressible capacitor with a shielding layer is circular, with a diameter of 2 mm; the thickness of the flexible compressible dielectric layer 101 is 100 μm, and it is made of polydimethylsiloxane foam, and the pore size of the polydimethylsiloxane foam is 10 μm; the thickness of the flexible electrode layer 102 is 5 μm, and it is made of a flexible conductive material; the thickness of the flexible dielectric layer 103 is 200 μm, and it is made of polydimethylsiloxane; the thickness of the flexible shielding layer 104 is 5 μm, and it is made of a flexible conductive material.
[0049] The inductor 2 is a 1206 chip inductor, and its inductance value is 1 μH.
[0050] The signal wire 3 is a copper wire covered with an insulating layer.
[0051] The shielded conductor 4 is a copper conductor covered with an insulating layer.
[0052] The signal acquisition module 5 includes a frequency data acquisition card and a 32-bit microcontroller; the first flexible electrode layer 102 is electrically connected to the frequency data acquisition card through the first signal wire 3, the inductor 2, and the second signal wire 3 in sequence; the second flexible electrode layer 102 is electrically connected to the frequency data acquisition card through the third signal wire 3; the frequency data acquisition card is electrically connected to the 32-bit microcontroller.
[0053] The preparation steps of the polydimethylsiloxane foam are as follows:
[0054] Step 1: mixing a polydimethylsiloxane prepolymer solution and a curing agent in a mass ratio of 10:1 to obtain a polydimethylsiloxane solution;
[0055] Step 2: Add sugar particles to the polydimethylsiloxane solution at a volume ratio of 10% and stir evenly to obtain a mixed solution;
[0056] Step 3: heating and curing the mixture at 60° C. for 6 h to obtain polydimethylsiloxane foam containing sugar;
[0057] Step 4: Put the polydimethylsiloxane foam containing sugar into 50° C. warm water to dissolve it, so as to obtain polydimethylsiloxane foam.
[0058] The preparation steps of the flexible conductive material are as follows:
[0059] Step 1: mixing a polydimethylsiloxane prepolymer solution and a curing agent in a mass ratio of 10:1 to obtain a polydimethylsiloxane solution;
[0060] Step 2: Adding conductive carbon black particles to the polydimethylsiloxane solution at a mass ratio of 1:10 and stirring evenly to obtain a mixed solution;
[0061] Step 3: Heat and cure the mixture at 60° C. for 6 hours to obtain a flexible conductive material.
[0062] Embodiment 2
[0063] A flexible capacitive pressure sensor using a frequency modulated signal, comprising a flexible compressible capacitor with a shielding layer, an inductor 2, three signal wires 3, two shielding wires 4, and a signal acquisition module 5;
[0064] The flexible compressible capacitor with a shielding layer comprises a flexible compressible dielectric layer 101, two flexible electrode layers 102, two flexible dielectric layers 103, and two flexible shielding layers 104; the flexible compressible dielectric layer 101 is sandwiched between the two flexible electrode layers 102; the flexible compressible dielectric layer 101 and the two flexible electrode layers 102 are both sandwiched between the two flexible dielectric layers 103; the flexible compressible dielectric layer 101, the two flexible electrode layers 102, and the two flexible dielectric layers 103 are both sandwiched between the two flexible shielding layers 104;
[0065] The first flexible electrode layer 102 is electrically connected to the signal acquisition module 5 through the first signal wire 3, the inductor 2, and the second signal wire 3 in sequence; the second flexible electrode layer 102 is electrically connected to the signal acquisition module 5 through the third signal wire 3; the two flexible shielding layers 104 are grounded through two shielding wires 4 respectively.
[0066] The flexible compressible capacitor with a shielding layer is circular, with a diameter of 50 mm; the thickness of the flexible compressible dielectric layer 101 is 2000 μm, and it is made of polydimethylsiloxane foam, and the pore size of the polydimethylsiloxane foam is 30 μm; the thickness of the flexible electrode layer 102 is 20 μm, and it is made of a flexible conductive material; the thickness of the flexible dielectric layer 103 is 2000 μm, and it is made of polydimethylsiloxane; the thickness of the flexible shielding layer 104 is 20 μm, and it is made of a flexible conductive material.
[0067] The inductor 2 is a 1206 chip inductor, and its inductance value is 1mH.
[0068] The signal wire 3 is a copper wire covered with an insulating layer.
[0069] The shielded conductor 4 is a copper conductor covered with an insulating layer.
[0070] The signal acquisition module 5 includes a frequency data acquisition card and a 32-bit microcontroller; the first flexible electrode layer 102 is electrically connected to the frequency data acquisition card through the first signal wire 3, the inductor 2, and the second signal wire 3 in sequence; the second flexible electrode layer 102 is electrically connected to the frequency data acquisition card through the third signal wire 3; the frequency data acquisition card is electrically connected to the 32-bit microcontroller.
[0071] The preparation steps of the polydimethylsiloxane foam are as follows:
[0072] Step 1: mixing a polydimethylsiloxane prepolymer solution and a curing agent in a mass ratio of 10:1 to obtain a polydimethylsiloxane solution;
[0073] Step 2: Add sugar particles to the polydimethylsiloxane solution at a volume ratio of 60% and stir evenly to obtain a mixed solution;
[0074] Step 3: heating and curing the mixture at 60° C. for 6 h to obtain polydimethylsiloxane foam containing sugar;
[0075] Step 4: Put the polydimethylsiloxane foam containing sugar into 50° C. warm water to dissolve it, so as to obtain polydimethylsiloxane foam.
[0076] The preparation steps of the flexible conductive material are as follows:
[0077] Step 1: mixing a polydimethylsiloxane prepolymer solution and a curing agent in a mass ratio of 10:1 to obtain a polydimethylsiloxane solution;
[0078] Step 2: Adding conductive carbon black particles to the polydimethylsiloxane solution at a mass ratio of 1:10 and stirring evenly to obtain a mixed solution;
[0079] Step 3: Heat and cure the mixture at 60° C. for 6 hours to obtain a flexible conductive material.
[0080] Embodiment 3
[0081] A flexible capacitive pressure sensor using a frequency modulated signal, comprising a flexible compressible capacitor with a shielding layer, an inductor 2, three signal wires 3, two shielding wires 4, and a signal acquisition module 5;
[0082] The flexible compressible capacitor with a shielding layer comprises a flexible compressible dielectric layer 101, two flexible electrode layers 102, two flexible dielectric layers 103, and two flexible shielding layers 104; the flexible compressible dielectric layer 101 is sandwiched between the two flexible electrode layers 102; the flexible compressible dielectric layer 101 and the two flexible electrode layers 102 are both sandwiched between the two flexible dielectric layers 103; the flexible compressible dielectric layer 101, the two flexible electrode layers 102, and the two flexible dielectric layers 103 are both sandwiched between the two flexible shielding layers 104;
[0083] The first flexible electrode layer 102 is electrically connected to the signal acquisition module 5 through the first signal wire 3, the inductor 2, and the second signal wire 3 in sequence; the second flexible electrode layer 102 is electrically connected to the signal acquisition module 5 through the third signal wire 3; the two flexible shielding layers 104 are grounded through two shielding wires 4 respectively.
[0084] The flexible compressible capacitor with a shielding layer is circular, with a diameter of 26 mm; the thickness of the flexible compressible dielectric layer 101 is 1000 μm, and it is made of polydimethylsiloxane foam, and the pore size of the polydimethylsiloxane foam is 20 μm; the thickness of the flexible electrode layer 102 is 12 μm, and it is made of a flexible conductive material; the thickness of the flexible dielectric layer 103 is 1100 μm, and it is made of polydimethylsiloxane; the thickness of the flexible shielding layer 104 is 12 μm, and it is made of a flexible conductive material.
[0085] The inductor 2 is a 1206 chip inductor, and its inductance value is 500 μH.
[0086] The signal wire 3 is a copper wire covered with an insulating layer.
[0087] The shielded conductor 4 is a copper conductor covered with an insulating layer.
[0088] The signal acquisition module 5 includes a frequency data acquisition card and a 32-bit microcontroller; the first flexible electrode layer 102 is electrically connected to the frequency data acquisition card through the first signal wire 3, the inductor 2, and the second signal wire 3 in sequence; the second flexible electrode layer 102 is electrically connected to the frequency data acquisition card through the third signal wire 3; the frequency data acquisition card is electrically connected to the 32-bit microcontroller.
[0089] The preparation steps of the polydimethylsiloxane foam are as follows:
[0090] Step 1: mixing a polydimethylsiloxane prepolymer solution and a curing agent in a mass ratio of 10:1 to obtain a polydimethylsiloxane solution;
[0091] Step 2: Add sugar particles to the polydimethylsiloxane solution at a volume ratio of 35% and stir evenly to obtain a mixed solution;
[0092] Step 3: heating and curing the mixture at 60° C. for 6 h to obtain polydimethylsiloxane foam containing sugar;
[0093] Step 4: Put the polydimethylsiloxane foam containing sugar into 50° C. warm water to dissolve it, so as to obtain polydimethylsiloxane foam.
[0094] The preparation steps of the flexible conductive material are as follows:
[0095] Step 1: mixing a polydimethylsiloxane prepolymer solution and a curing agent in a mass ratio of 10:1 to obtain a polydimethylsiloxane solution;
[0096] Step 2: Adding conductive carbon black particles to the polydimethylsiloxane solution at a mass ratio of 1:10 and stirring evenly to obtain a mixed solution;
[0097] Step 3: Heat and cure the mixture at 60° C. for 6 hours to obtain a flexible conductive material.
[0098] Although the specific embodiments of the present invention are described above, it should be understood by those skilled in the art that these are only examples, and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.
Claims
1. A flexible capacitive pressure sensor using a frequency modulated signal, characterized in that: It comprises a flexible compressible capacitor with a shielding layer, an inductor (2), three signal wires (3), two shielding wires (4), and a signal acquisition module (5); The flexible compressible capacitor with a shielding layer comprises a flexible compressible dielectric layer (101), two flexible electrode layers (102), two flexible dielectric layers (103), and two flexible shielding layers (104); the flexible compressible dielectric layer (101) is sandwiched between the two flexible electrode layers (102); the flexible compressible dielectric layer (101) and the two flexible electrode layers (102) are both sandwiched between the two flexible dielectric layers (103); the flexible compressible dielectric layer (101), the two flexible electrode layers (102), and the two flexible dielectric layers (103) are both sandwiched between the two flexible shielding layers (104); The first flexible electrode layer (102) is electrically connected to the signal acquisition module (5) via the first signal wire (3), the inductor (2), and the second signal wire (3) in sequence; the second flexible electrode layer (102) is electrically connected to the signal acquisition module (5) via the third signal wire (3); and the two flexible shielding layers (104) are grounded respectively via the two shielding wires (4); The flexible compressible capacitor with a shielding layer is circular, with a diameter of 2 mm to 50 mm; the thickness of the flexible compressible dielectric layer (101) is 100 μm to 2000 μm, and it is made of polydimethylsiloxane foam, and the pore size of the polydimethylsiloxane foam is 10 μm to 30 μm; the thickness of the flexible electrode layer (102) is 5 μm to 20 μm, and it is made of a flexible conductive material; the thickness of the flexible dielectric layer (103) is 200 μm to 2000 μm, and it is made of polydimethylsiloxane; the thickness of the flexible shielding layer (104) is 5 μm to 20 μm, and it is made of a flexible conductive material.
2. The flexible capacitive pressure sensor using a frequency modulated signal according to claim 1, characterized in that: The inductor (2) is a 1206 chip inductor, and its inductance value is 1μH~1mH.
3. The flexible capacitive pressure sensor using a frequency modulation signal according to claim 1, characterized in that: The signal wire (3) is a copper wire coated with an insulating layer.
4. The flexible capacitive pressure sensor using a frequency modulation signal according to claim 1, characterized in that: The shielded conductor (4) is a copper conductor coated with an insulating layer.
5. The flexible capacitive pressure sensor using a frequency modulation signal according to claim 1, characterized in that: The signal acquisition module (5) comprises a frequency data acquisition card and a 32-bit microcontroller; the first flexible electrode layer (102) is electrically connected to the frequency data acquisition card via a first signal wire (3), an inductor (2), and a second signal wire (3) in sequence; the second flexible electrode layer (102) is electrically connected to the frequency data acquisition card via a third signal wire (3); and the frequency data acquisition card is electrically connected to the 32-bit microcontroller.
6. The flexible capacitive pressure sensor using a frequency modulation signal according to claim 1, characterized in that: The preparation steps of the polydimethylsiloxane foam are as follows: Step 1: mixing a polydimethylsiloxane prepolymer solution and a curing agent in a mass ratio of 10:1 to obtain a polydimethylsiloxane solution; Step 2: Add sugar particles to the polydimethylsiloxane solution at a volume ratio of 10% to 60% and stir evenly to obtain a mixed solution; Step 3: heating and curing the mixture at 60° C. for 6 h to obtain polydimethylsiloxane foam containing sugar; Step 4: Put the polydimethylsiloxane foam containing sugar into 50° C. warm water to dissolve it, so as to obtain polydimethylsiloxane foam.
7. The flexible capacitive pressure sensor using a frequency modulation signal according to claim 1, characterized in that: The preparation steps of the flexible conductive material are as follows: Step 1: mixing a polydimethylsiloxane prepolymer solution and a curing agent in a mass ratio of 10:1 to obtain a polydimethylsiloxane solution; Step 2: Adding conductive carbon black particles to the polydimethylsiloxane solution at a mass ratio of 1:10 and stirring evenly to obtain a mixed solution; Step 3: Heat and cure the mixed solution at 60° C. for 6 hours to obtain a flexible conductive material.