Device for calibrating PVDF (Polyvinylidene Fluoride) pressure sensor by using pressure air bag device
By combining a pressure bladder device and a charge amplification circuit, the problem of inaccurate calibration of PVDF piezoelectric films is solved, and accurate calibration and circuit matching of PVDF pressure sensors are achieved, making them suitable for pressure testing of spacecraft.
Patent Information
- Application Number
- CN202423073967.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-12
- Publication Date
- 2025-12-02
- Estimated Expiration
- 2034-12-12
AI Technical Summary
The lack of a unified calibration standard in existing technologies leads to inaccurate calibration of PVDF piezoelectric film pressure sensors. Traditional pressure testing equipment is bulky, consumes a lot of power, and is difficult to install, which affects the reliability verification of spacecraft structures.
A pressure airbag device is used to calibrate the PVDF pressure sensor. The airbag and PVDF film are fixed by the airbag fixing device and connected to the charge amplification circuit and the acquisition card. The constant inflation device of the airbag converts the pressure into current, ensuring that the PVDF film is subjected to uniform force and the circuit is matched.
It achieves accurate calibration of PVDF pressure sensors, eliminates errors caused by uneven force and inconsistent response speed, and ensures the accuracy and consistency of calibration, making it suitable for pressure testing of spacecraft.
Smart Images
Figure CN223623755U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the technical field of pressure sensor calibration devices, and specifically relates to a device for calibrating PVDF pressure sensors using a pressure airbag device. Background Technology
[0002] Modern spacecraft equipment has complex structures, requiring static tests to theoretically verify these structures. Traditional pressure testing equipment is bulky, consumes a lot of power, is difficult to install, and has large testing errors. Therefore, finding a universal pressure testing device for static verification to ensure the reliability of spacecraft structures is an urgent problem to be solved.
[0003] PVDF piezoelectric films are flexible materials with high mechanical strength, high sensitivity, temperature stability, and fast response speed, exhibiting excellent environmental adaptability. In recent years, they have been widely used in pressure testing of various aerospace vehicles. Currently, there is no unified calibration standard for PVDF, and the calibration of PVDF piezoelectric films affects the accuracy of testing. PVDF calibration mainly addresses the quantitative measurement of the sensor's output charge, thereby calibrating the pressure. Utility Model Content
[0004] In order to solve the above-mentioned problems in the existing technology, the purpose of this utility model is to provide a device for calibrating PVDF pressure sensors using a pressure airbag device.
[0005] The technical solution adopted in this utility model is as follows:
[0006] A device for calibrating a PVDF pressure sensor using a pressure airbag includes an airbag, an airbag fixing device, a charge amplification circuit, and a data acquisition card. The airbag is placed on the PVDF film to be tested, the airbag fixing device fixes the airbag and the PVDF film, the PVDF film is electrically connected to the charge amplification circuit, and the charge amplification circuit is electrically connected to the data acquisition card.
[0007] This invention employs a pressure airbag and proposes a calibration method using a constant inflation device. This calibration method converts the pressure of the PVDF film into current and transforms the high impedance of the PVDF film input into low impedance for convenient circuit matching. The pressure and flow rate of the airbag are controllable, eliminating calibration inaccuracies caused by uneven force and inconsistent response speeds.
[0008] An airbag is placed on the PVDF film to be tested and secured with an airbag fixing device to ensure complete coverage of the film. The PVDF film is connected to a charge amplification circuit via electrodes and then to a data acquisition card. During use, the airbag is inflated at a constant rate through the airbag inflation valve. The PVDF film generates a charge due to the airbag pressure, producing a current across a parallel resistor in the charge amplification circuit. The input voltage through this resistor is amplified and then acquired by the data acquisition card.
[0009] This invention ensures a consistent calibration environment for each test, uniform stress on the PVDF film, and guarantees calibration accuracy. An airbag ensures consistent pressure across the entire film patch, preventing errors caused by uneven pressure. An airbag inflation valve and fixing device ensure accurate pressure calculation and controllable inflation speed, guaranteeing calibration is performed at the same response speed of the piezoelectric film, resulting in consistent charge-time derivatives and constant current. The charge is converted into current across the resistor; the parallel resistor reduces the high input impedance of the PVDF film, facilitating circuit matching.
[0010] As a preferred embodiment of this utility model, the airbag is connected to an airbag inflation valve.
[0011] As a preferred embodiment of this utility model, the airbag fixing device includes an upper plate and a lower plate, with a plurality of connecting columns connecting the upper plate and the lower plate, and the upper plate and the lower plate clamping the airbag and the PVDF film.
[0012] As a preferred embodiment of this utility model, the airbag is fully covered by a PVDF film.
[0013] As a preferred embodiment of this utility model, the PVDF film is provided with electrodes, and the PVDF film is connected to the charge amplification circuit through the electrodes.
[0014] As a preferred embodiment of this utility model, the charge amplification circuit includes a resistor and a voltage amplifier. The resistor is connected in parallel with the PVDF film, and the two ends of the resistor are electrically connected to the output terminal of the voltage amplifier. The output terminal of the voltage amplifier is electrically connected to the data acquisition card.
[0015] The beneficial effects of this utility model are as follows:
[0016] This invention ensures a consistent calibration environment for each test, uniform stress on the PVDF film, and guarantees calibration accuracy. An airbag ensures consistent pressure across the entire film patch, preventing errors caused by uneven pressure. An airbag inflation valve and fixing device ensure accurate pressure calculation and controllable inflation speed, guaranteeing calibration is performed at the same response speed of the piezoelectric film, resulting in consistent charge-time derivatives and constant current. The charge is converted into current across the resistor; the parallel resistor reduces the high input impedance of the PVDF film, facilitating circuit matching. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the structural layout of the calibration equipment of this utility model;
[0018] Figure 2 This is a structural diagram of the airbag and airbag fixation device;
[0019] Figure 3 This is a schematic diagram of a charge amplifier circuit;
[0020] Figure 4This is a flowchart of the process of this utility model.
[0021] In the diagram: 1-Airbag; 2-Airbag inflation valve; 3-Airbag fixing device; 4-Charge amplification circuit; 5-Data acquisition card. Detailed Implementation
[0022] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0023] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be combined with each other.
[0024] like Figures 1-3 As shown, the device for calibrating a PVDF pressure sensor using a pressure airbag device in this embodiment includes an airbag 1, an airbag 1 fixing device, a charge amplification circuit 4, and a data acquisition card 5. The airbag 1 is placed on the PVDF film to be tested, the airbag 1 fixing device fixes the airbag 1 and the PVDF film, the PVDF film is electrically connected to the charge amplification circuit 4, and the charge amplification circuit 4 is electrically connected to the data acquisition card 5.
[0025] The airbag 1 is equipped with an airbag inflation valve.
[0026] The airbag 1 fixing device includes an upper plate and a lower plate, with several connecting posts connecting the upper plate and the lower plate, which clamp the airbag 1 and the PVDF film together.
[0027] The airbag 1 is fully covered by a PVDF film.
[0028] The PVDF film is provided with electrodes, and the PVDF film is connected to the charge amplification circuit 4 through the electrodes.
[0029] The charge amplification circuit 4 includes a resistor and a voltage amplifier. The resistor is connected in parallel with the PVDF film, and the two ends of the resistor are electrically connected to the output terminal of the voltage amplifier. The output terminal of the voltage amplifier is electrically connected to the acquisition card 5.
[0030] Airbag 1 is placed on the PVDF film to be tested and secured with the airbag 1 fixing device to ensure that airbag 1 completely covers the PVDF film. See Figure 2 The PVDF film is connected to the charge amplifier circuit 4 via electrodes and then to the data acquisition card 5. During use, the airbag 1 is inflated at a constant speed through its inflation valve. The PVDF film generates a charge due to the pressure of the airbag 1, which in turn generates a current across the parallel resistor in the charge amplifier circuit 4. The main structure of the charge amplifier circuit 4 is as follows: Figure 3 As shown. The input voltage of this resistor is amplified and acquired by data acquisition card 5, outputting the voltage-time Vt curve. The output charge Q satisfies:
[0031]
[0032] Where T is the cycle of acquisition card 5, A is a fixed coefficient, i=1 is the inflation start time point, and i=N is the time point with no voltage output.
[0033] Since pressure and charge Q have a linear relationship, we have:
[0034]
[0035] In this calculation, the pressure F is calculated by inflating gas into airbag 1, and S is the contact area between the PVDF film and airbag 1. Multiple measurements are taken to obtain the coefficient K through linear fitting, thereby calibrating the relationship between pressure and output voltage. The specific workflow is as follows: Figure 4 As shown.
[0036] This invention employs a pressure airbag 1 and proposes a calibration method using a constant inflation device. This calibration method converts the pressure of the PVDF film into current and transforms the high impedance of the PVDF film input into low impedance for convenient circuit matching. The pressure and flow rate of the airbag 1 are controllable, eliminating calibration inaccuracies caused by uneven force and inconsistent response speeds.
[0037] This invention ensures a consistent calibration environment for each test, uniform stress on the PVDF film, and guarantees calibration accuracy. An airbag 1 ensures consistent pressure across the entire film patch, preventing errors due to uneven pressure. The airbag 1 inflation valve and fixing device ensure accurate pressure calculation and controllable inflation speed, guaranteeing calibration is performed at the same response speed of the piezoelectric film, resulting in consistent charge-time differential and constant current. The charge is converted into current across the resistor; the parallel resistor reduces the high input impedance of the PVDF film, facilitating circuit matching.
[0038] This utility model is not limited to the above-mentioned optional embodiments. Anyone can derive other forms of products under the guidance of this utility model. However, regardless of any changes made in its shape or structure, any technical solution that falls within the scope of the claims of this utility model shall be protected by this utility model.
Claims
1. A device for calibrating a PVDF pressure sensor using a pressure airbag, characterized in that: It includes an airbag (1), an airbag (1) fixing device, a charge amplification circuit (4) and a data acquisition card (5). The airbag (1) is placed on the PVDF film to be tested. The airbag (1) fixing device fixes the airbag (1) and the PVDF film. The PVDF film is electrically connected to the charge amplification circuit (4), and the charge amplification circuit (4) is electrically connected to the data acquisition card (5).
2. The apparatus for calibrating a PVDF pressure sensor using a pressure airbag device according to claim 1, characterized in that: An airbag (1) inflation valve is connected to the airbag (1).
3. The apparatus for calibrating a PVDF pressure sensor using a pressure airbag device according to claim 1, characterized in that: The airbag (1) fixing device includes an upper plate and a lower plate, with several connecting columns connected between the upper plate and the lower plate, and the upper plate and the lower plate clamp the airbag (1) and the PVDF film.
4. The apparatus for calibrating a PVDF pressure sensor using a pressure airbag device according to claim 1, characterized in that: The airbag (1) is fully covered by a PVDF film.
5. The apparatus for calibrating a PVDF pressure sensor using a pressure airbag device according to claim 1, characterized in that: The PVDF film is provided with electrodes, and the PVDF film is connected to the charge amplification circuit (4) through the electrodes.
6. The apparatus for calibrating a PVDF pressure sensor using a pressure airbag device according to claim 1, characterized in that: The charge amplification circuit (4) includes a resistor and a voltage amplifier. The resistor is connected in parallel with the PVDF film, and the two ends of the resistor are electrically connected to the output of the voltage amplifier. The output of the voltage amplifier is electrically connected to the acquisition card (5).