Device and system for simulating built-in charge amplification type piezoelectric accelerometer

Abstract

The utility model discloses a device and a system for simulating a built-in charge amplification type piezoelectric accelerometer, the device comprises a plurality of capacitors, a plurality of resistors and a plurality of dial switches, the dial switches can adjust the connection relation of partial or all resistors in the plurality of resistors so as to form an equivalent resistor; the equivalent resistor and a part of or all of the capacitors form an equivalent resistance-capacitance circuit in which an equivalent resistor R and an equivalent capacitor C are connected in series, and the equivalent resistor R is equal to or approximately equal to the equivalent resistor of the built-in charge amplification type piezoelectric accelerometer. And the equivalent capacitance C is equal to or approximately equal to the equivalent capacitance of the built-in charge amplification type piezoelectric accelerometer. The device can serve as a scheme which is high in speed, low in cost and high in precision, a built-in charge amplification type piezoelectric accelerometer is simulated, and furthermore, the device is matched with a signal generator and a data acquisition device, so that inspection and verification of the data acquisition device can be realized.

Description

Technical Field

[0001] The utility model belongs to the field of signals and sensors, and particularly relates to a device and a system for simulating an internally-mounted charge-amplified piezoelectric accelerometer. Background Art

[0002] PCB Piezotronics, Inc., namely PCB® company, is committed to the research, development and product manufacturing of piezoelectric measurement technologies. It is a company that researches, develops and manufactures impact, vibration, force, pressure, strain, torque, acoustic sensors and measuring instruments. Its sensors are widely used in fields such as aviation, aerospace, shipbuilding, ordnance, nuclear industry, petrochemical, hydraulic, electric power, light industry, transportation and vehicles. The ICP® (i.e., sensor-integrated charge amplifier) technology it proposed makes the use of sensors more convenient, and these ICP® technologies have occupied a considerable share in today's dynamic testing field.

[0003] Internally-mounted charge-amplified accelerometers, usually known to those skilled in the art as ICP (Integrated Circuit Piezoelectric) or IEPE (Integrated Electronics Piezo-Electric), are sensors that use the piezoelectric effect principle to measure acceleration. They integrate a sensing element (piezoelectric crystal) and a signal conditioning circuit (including a charge amplifier, etc.) to form a complete, plug-and-play measurement system.

[0004] With the rapid development of modern electronic technologies, various vibration acquisition and analysis instruments and secondary instruments for unit operation protection are becoming more and more widely used. Therefore, the inspection and calibration of the input channels of these acquisition hardware and secondary instruments have become increasingly important, and there is a strong user demand.

[0005] Traditional inspection and calibration devices use a portable vibration table to excite the accelerometer and use the output signal of the accelerometer to inspect and calibrate the input channels of the acquisition instrument, which have technical problems such as high cost, low efficiency and poor accuracy. However, there has long been a lack of mature and simple tools and their inspection and calibration solutions in the market to solve this technical problem.

[0006] The above information disclosed in the background art section is only used to enhance the understanding of the background of the utility model, and thus may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Utility Model

[0007] Aiming at the deficiencies in the prior art, the purpose of the utility model is to provide a device for simulating an internally-mounted charge-amplified piezoelectric accelerometer and an inspection and calibration system for a data collector, so as to overcome the problems of high cost, low efficiency and poor accuracy existing in the traditional solution.

[0008] To achieve the above object, the present utility model provides the following technical solutions:

[0009] A device for simulating a built-in charge amplifier type piezoelectric accelerometer, comprising:

[0010] A plurality of capacitors, a plurality of resistors and a plurality of DIP switches, wherein,

[0011] The DIP switch can adjust the connection relationship of some or all of the plurality of resistors to form an equivalent resistance;

[0012] The equivalent resistance and some or all of the plurality of capacitors constitute an equivalent resistance-capacitance circuit in which the equivalent resistance R and the equivalent capacitance C are connected in series, wherein,

[0013] The equivalent resistance R in the equivalent resistance-capacitance circuit is equal to or approximately equal to the equivalent resistance of the built-in charge amplifier type piezoelectric accelerometer,

[0014] The equivalent capacitance C in the equivalent resistance-capacitance circuit is equal to or approximately equal to the equivalent capacitance of the built-in charge amplifier type piezoelectric accelerometer.

[0015] Preferably,

[0016] The connection relationship of some or all of the resistors includes: series connection, parallel connection, or series-parallel connection to form a mixed connection.

[0017] Preferably,

[0018] The DIP switch can also adjust the connection relationship of some or all of the plurality of capacitors to form an equivalent capacitance.

[0019] Preferably,

[0020] The connection relationship of some or all of the capacitors includes: series connection, parallel connection, or series-parallel connection to form a mixed connection.

[0021] Preferably,

[0022] The input end of the device is used to connect to a signal generator.

[0023] Preferably,

[0024] The output end of the device is used to connect to a data collector.

[0025] In addition, the present utility model also discloses a test and calibration system for a data collector, which includes:

[0026] A signal generator, the device described above, and a data collector, wherein,

[0027] The input end of the described device is connected to a signal generator, and the output end of the described device is connected to a data collector.

[0028] Compared with the prior art, the beneficial effects brought by the present utility model are as follows: The device for simulating an internally built charge amplifier type piezoelectric accelerometer disclosed by the present utility model can be used as a solution with high speed, low cost, and high precision to simulate an internally built charge amplifier type piezoelectric accelerometer. Further, the device, in cooperation with a signal generator and a data collector, can realize the inspection and calibration of the data collector.

[0029] The specific advantages of the present utility model include:

[0030] The ingeniously designed equivalent circuit not only uses a capacitor to block the influence of the constant current source power supply of the data collector on the signal generator, but also isolates the interference of the DC drift of the signal generator on the acquisition channel.

[0031] The values of the equivalent resistance and equivalent capacitance of the equivalent circuit are approximately equivalent to those of the equivalent resistance and equivalent capacitance of a real ICP / IEPE piezoelectric accelerometer (ideally, they are equal), and can simulate and "deceive" the data acquisition / secondary meter channel, making it think that a real accelerometer has been connected.

[0032] In this way, in cooperation with the signal of a signal generator (typically, a high-precision signal generator), the input channel and configuration of the data acquisition / secondary meter are verified or calibrated for accuracy / correctness.

[0033] In summary, compared with the traditional scheme of exciting a real accelerometer with a portable / fixed vibration table, the present utility model has high precision, high speed, and low cost, can conveniently and quickly perform on-site signal loop inspection and calibration of a high-precision data acquisition hardware system, greatly reduces the workload of on-site staff, and simultaneously greatly improves the accuracy of calibration and verification. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] By reading the detailed description of the preferred specific embodiments below, various other advantages and benefits of the present utility model will become clear to those of ordinary skill in the art. The accompanying drawings in the specification are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present utility model. Obviously, the drawings described below are only some embodiments of the present utility model, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts. Moreover, throughout the drawings, the same reference numerals are used to represent the same components.

[0035] Figure 1 It is a schematic diagram of a system for inspecting and calibrating a data collector in an embodiment of the present utility model;

[0036] Figure 2In another embodiment of the present utility model, it is a design diagram of a device for simulating an internally built charge amplifier type piezoelectric accelerometer;

[0037] Among them, the reference numerals are as follows:

[0038] Signal generator - 1, data collector - 2, equivalent capacitor - 3, equivalent resistor - 4. Specific embodiments

[0039] The following will refer to the attached Figures 1 to 2 The specific embodiments of the present utility model will be described in detail. Although specific embodiments of the present utility model are shown in the drawings, it should be understood that the present utility model can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present utility model and to be able to convey the scope of the present utility model completely to those skilled in the art.

[0040] It should be noted that in the description of the specification and claims, certain terms are used to refer to specific components. Those skilled in the art should understand that technicians may use different terms to refer to the same component. The description of the specification and claims does not use the difference in terms as a way to distinguish components, but uses the difference in the functions of components as the criterion for distinction. For example, the term "comprising" or "including" mentioned throughout the specification and claims is an open-ended term, so it should be interpreted as "including but not limited to". The subsequent description of the specification is the preferred embodiment for implementing the present utility model, but the description is for the purpose of the general principle of the specification and is not used to limit the scope of the present utility model. The protection scope of the present utility model shall be determined by the scope defined by the appended claims.

[0041] For the convenience of understanding the embodiments of the present utility model, the following will take specific embodiments as examples and further explain with reference to the drawings, and each drawing does not constitute a limitation to the embodiments of the present utility model.

[0042] In one embodiment, the present utility model provides a device for simulating an internally built charge amplifier type piezoelectric accelerometer, including:

[0043] Multiple capacitors, multiple resistors and multiple DIP switches, among which,

[0044] The DIP switch can adjust the connection relationship of some or all of the resistors among the multiple resistors to form an equivalent resistor;

[0045] The equivalent resistor and some or all of the capacitors among the multiple capacitors form an equivalent resistance-capacitance circuit in which the equivalent resistor R and the equivalent capacitor C are connected in series. Among them,

[0046] The equivalent resistance R in the equivalent resistance-capacitance circuit is equal to or approximately equal to the equivalent resistance of the built-in charge amplifier type piezoelectric accelerometer.

[0047] The equivalent capacitance C in the equivalent resistance-capacitance circuit is equal to or approximately equal to the equivalent capacitance of the built-in charge amplifier type piezoelectric accelerometer.

[0048] For the embodiment, the device actually provides an equivalent resistance-capacitance (RC) circuit that simulates a real ICP / IEPE accelerometer, i.e., the built-in charge amplifier type piezoelectric accelerometer. Together with the DIP switch, it can simulate the equivalent resistance and capacitance characteristics of different real accelerometers. It can be understood that when the device is combined with a signal generator, the device can simulate the response characteristics of such accelerometers at different frequencies, thus serving as a test and calibration tool.

[0049] In another embodiment,

[0050] The connection relationships of some or all of the resistors include: series connection, parallel connection, or series-parallel connection to form a mixed connection.

[0051] In another embodiment,

[0052] The DIP switch can also adjust the connection relationships of some or all of the multiple capacitors to form an equivalent capacitance.

[0053] In another embodiment,

[0054] The connection relationships of some or all of the capacitors include: series connection, parallel connection, or series-parallel connection to form a mixed connection.

[0055] In another embodiment,

[0056] The input end of the device is used to connect to a signal generator.

[0057] In another embodiment,

[0058] The output end of the device is used to connect to a data collector. The data collector is, for example, a data acquisition system including software and hardware, etc.

[0059] In another embodiment, the present utility model also discloses a verification and calibration system for a data collector, which includes:

[0060] A signal generator, the device, and a data collector, wherein,

[0061] The input end of the device is connected to the signal generator, and the output end of the device is connected to the data collector.

[0062] See Figure 1 , Exemplarily, in the verification and calibration system of the data collector,

[0063] As described above, the DIP switch can connect some or all of the capacitors in the device of the analog built-in charge amplifier type piezoelectric accelerometer through its switch setting to form an equivalent capacitor C-3. The DIP switch can also connect some or all of the resistors in the device through its switch setting to form an equivalent resistor R-4. Among them, the equivalent capacitor C and the equivalent resistor R are in a series relationship.

[0064] The signal generator - 1 has two output terminals, namely the signal generator + terminal and the signal generator - terminal, where

[0065] The signal generator + terminal is connected to one end of the equivalent capacitor C-3 in the device.

[0066] The other end of the equivalent capacitor C is not only connected to one end of the data collector - 2 through the acquisition channel + terminal, but also connected to one end of the equivalent resistor R-4.

[0067] The signal generator - terminal is connected to the other end of the equivalent resistor R-4 in the device.

[0068] The other end of the equivalent resistor R is connected to the other end of the data collector - 2 through the acquisition channel - terminal.

[0069] It can be understood that the signal generator is used to simulate the voltage change caused by external vibration. By adjusting the voltage amplitude and frequency of its output, vibration signals under different conditions can be simulated. These signals act on the device, and then the data collector evaluates the response characteristics of the device (even a real accelerometer) under various or characteristic vibration conditions. Under the action of the signal generator, the device actually outputs an analog voltage signal, representing the "measured" acceleration change. This corresponds to the following working process of a real such accelerometer: object vibration → the piezoelectric element of the accelerometer generates charge, and then the built-in signal processing circuit of the accelerometer (mainly amplifying the signal) outputs a dynamic voltage signal → the data collector performs single-ended / differential input acquisition. For those skilled in the art, it is well known that the data collector can be a data acquisition system, which can further process and analyze the signal. It should be noted that the present invention does not involve any improvement to the signal generator itself or the data collector itself, but uses the signal generator to generate various signals to simulate vibration, and then uses the device coupled between the signal generator and the data collector to realize the simulation of the built-in charge amplifier type piezoelectric accelerometer, so as to be used for the inspection and calibration of the data collector.

[0070] For example, the inspection and calibration system can implement the following specific method, including the following steps:

[0071] The signal generator generates an AC voltage signal as the excitation signal, which is injected through the positive and negative input terminals of the equivalent circuit; this signal simulates the voltage change generated by vibration.

[0072] The equivalent circuit of the device outputs a voltage signal based on the excitation signal, and the voltage signal is transmitted to the data collector through the "+" terminal and "-" terminal of the acquisition channel.

[0073] Typically, the data collector records the amplitude and phase of the voltage signal. Naturally, by comparing with a real accelerometer, it can be evaluated whether the performance of the device is close to that of a real accelerometer, so as to realize the inspection and calibration of the data acquisition instrument, that is, the data collector or the secondary meter.

[0074] It can be understood that the equivalent resistance R and equivalent capacitance C of the equivalent circuit determine the frequency response characteristics of the equivalent circuit. At low frequencies, the influence of the capacitance is small, and the resistive component of the circuit dominates, so that the voltage signal passes through almost without attenuation.

[0075] Furthermore, in one embodiment, the method for pre-adjusting the equivalent resistance and equivalent capacitance of the equivalent circuit is as follows:

[0076] Benchmark test: First, use a real accelerometer with known qualified accuracy (for example, assume that the response curve standard of the qualified accelerometer is: the frequency response at 1 kHz drops between -2.5 dB and -3.5 dB). Using the signal generator, test the real accelerometer under certain test conditions and record its actual frequency response curve.

[0077] Equivalent circuit verification: Then, use the equivalent circuit to simulate different resistor-capacitor combinations and record their frequency responses under the same test conditions.

[0078] Taking 1 kHz as an example, if the output of the equivalent circuit drops by -3 dB at this frequency point, and this result is consistent with the response curve of the qualified accelerometer within the error range (taking into account measurement errors and environmental factors), it can be considered that the simulation of the equivalent circuit at this frequency point is effective; if the consistent standard is not reached, adjust the equivalent resistance and equivalent capacitance of the equivalent circuit until it meets the standard.

[0079] Furthermore, the pre-adjustment method further includes the following steps:

[0080] Comprehensive analysis: Conduct the above-mentioned benchmark tests and equivalent circuit verifications across the entire frequency range, and then perform comparative analysis to ensure that the responses of the equivalent circuit at all key frequency points are within the allowable error range compared to those of a qualified accelerometer. Ultimately, this results in: The equivalent resistance R in the equivalent resistance-capacitance circuit is equal to or approximately equal to the equivalent resistance of the built-in charge amplifier piezoelectric accelerometer, and the equivalent capacitance C in the equivalent resistance-capacitance circuit is equal to or approximately equal to the equivalent capacitance of the built-in charge amplifier piezoelectric accelerometer. Thus, the device disclosed in the present invention for simulating a built-in charge amplifier piezoelectric accelerometer is suitable for use as a standard reference for inspection and calibration.

[0081] Here, it should be noted that

[0082] Since the equivalent capacitance passes alternating current and blocks direct current, this causes the alternating current signal of the signal generator to be loaded across the equivalent resistance; at the same time, the characteristic of the capacitor blocking direct current prevents the constant current power supply on the acquisition channel side from affecting the signal generator, without affecting the output signal accuracy of the signal generator, ensuring the working environment of the signal generator and the accuracy during the operation of the entire system;

[0083] Since the + / − ends of the acquisition channel are also connected across the equivalent resistance, the precise alternating current signal emitted by the signal generator is thus loaded across the input channels of the data acquisition / secondary instrument.

[0084] Furthermore, in another embodiment,

[0085] When the constant current source (such as a common 2 - 8 mA) output from the positive of the data acquisition / secondary instrument channel flows through the equivalent resistance, since the equivalent resistance can be adjusted by a DIP switch, then by adjusting the resistance value, the offset voltage (exemplarily, generally 4 - 12 V, depending on the design of the instrument manufacturer) when the real accelerometer is working properly can be presented, and the data acquisition / secondary instrument channel will consider that a real accelerometer is connected to the channel and can collect signals.

[0086] In this way, the device realizes the simulation of a real accelerometer and successfully "deceives" the data acquisition / secondary instrument to achieve the purpose of inspecting and calibrating the data collector in the present invention.

[0087] Furthermore, it can be understood that the present invention can achieve rapid and repeatable configuration adjustment at low cost by using a DIP switch to select different resistor or capacitor combinations. Refer to Figure 2 , which shows the design diagram of the device.

[0088] It can be found that BNC connectors are provided at both ends of the device to facilitate the rapid connection of the signal generator and the data collector, and after inspecting and calibrating one channel, it can be quickly disassembled and installed to monitor the next channel.

[0089] Exemplarily, the constant current supply current of the data collector has multiple values such as 2 mA, 4 mA, and 6 mA. The DIP switch can control the connection relationship of several parallel resistors to achieve a DC voltage value between 8 V and 12 V across the equivalent resistor.

[0090] Typically,

[0091] The signal generator - 1 sets a 159.2 Hz, 100 mv single - peak AC signal and outputs it through the + and - terminals of the signal generator;

[0092] When the AC signal flows through the equivalent capacitor 3, even weak DC unstable drift will be blocked by the capacitor; it can be understood that by selecting an appropriate capacitance value, the AC signal can pass through smoothly and be loaded across the equivalent resistor - 4.

[0093] Meanwhile, the data collector - 2's acquisition channel outputs a constant current of 2 / 4 / 6 / 8 mA, etc., for external power supply; it can be understood that without the equivalent capacitor - 3, this constant current will disturb the output of the signal generator - 1, but with the said equivalent capacitor, the current can only flow back to the - terminal of the acquisition channel through the resistor 4. If the resistance value of the equivalent resistor is appropriate, a DC voltage of 8 - 12 V will be generated across its two ends, which is the working voltage of a normal ICP / IEPE accelerometer in this example. Therefore, the data collector determines that the accelerometer is properly connected to the data collector based on this.

[0094] Exemplarily, the data collector can further start collecting the AC voltage signal between the two ends of the equivalent resistor, and can effectively determine whether the data collector is working properly by whether the AC voltage displayed by the software supporting the data collector is 100 mV single - peak. For example, it can determine whether the hardware analog - to - digital conversion channel and configuration of the data collector are working properly. It can be understood that when the AC voltage displayed by the software supporting the data collector is 100 mV single - peak, it can be considered that the inspection and calibration system is accurate. Thus, the device and the inspection and calibration system can be used to simulate a real accelerometer and perform inspection and calibration on the data collector.

[0095] In another embodiment,

[0096] The signal generator uses a Fluke 743B signal generator to output a 100 Hz, 100 mV peak - to - peak AC voltage signal. This signal is divided by the capacitive reactance and impedance of the equivalent circuit. The voltage across the equivalent resistor is 100 mV * 4300 / ((4300 + / 1(2 * 3.14 * 100 * 100)) = 99.999984%, and the error is 0.0016%, which is a negligible tiny error;

[0097] Taking the typical NI 9234 4-channel data acquisition device as an example, its channel supplies 2mA constant current to the outside, and the constant current power supply is blocked by the equivalent capacitor 3, and flows through the resistor in the equivalent circuit, such as the preferred precision resistor; at this time, only the 4 dip switches are connected to the dip switch 1, and the other 3 are disconnected, then the current flows through the 4300 ohm resistor, and the DC voltage is 8.6V. The data acquisition device determines that the DC voltage is the voltage of a normally working accelerometer (8-12VDC is normal), thereby "cheating" the data acquisition device. At the same time, the data acquisition device also collects the AC voltage signal through the acquisition channel, that is, the AC voltage loaded on this resistor by the signal generator.

[0098] Furthermore, by checking in the upper computer software of the data logger whether the data obtained from the test is a 100mV peak-to-peak signal and the error, the test accuracy and configuration can be evaluated.

[0099] It can be found that the equivalent resistor is not only applied with the AC voltage from the signal generator, but also with the DC voltage from the data acquisition device. The inspection and verification system first determines whether the DC voltage on the equivalent resistor is within the normal range or the error range, and then checks through the upper computer software of the data acquisition device whether the measured AC voltage is roughly consistent with the AC voltage provided by the signal generator or is within the error range.

[0100] Other similar examples include: 1) When the constant current provided by the digital logger is 4mA, connect the dip switches 1 and 2, and assuming the resistance value is 2150 ohms, the DC voltage is 8.6V; 2) When the constant current provided by the digital logger is 6mA, connect 3 dip switches, and make the DC voltage across the equivalent resistor still be 8.6V; 3) When the constant current provided by the digital logger is 8mA, connect 4 dip switches, and make the DC voltage across the equivalent resistor still be 8.6V.

[0101] That is to say, in addition to implementing inspection and verification through the response curve described above, the utility model can also implement the following DC voltage and AC voltage judgment method: first determine whether the DC voltage on the equivalent resistor is within the normal range or the error range, and then check through the upper computer software of the data logger whether the measured AC voltage is generally consistent with the AC voltage provided by the signal generator or is within the error range.

[0102] In summary, the device for simulating a piezoelectric accelerometer with built-in charge amplification disclosed in the utility model can be used as a fast, low-cost, and high-precision solution to simulate a piezoelectric accelerometer with built-in charge amplification. Furthermore, the device cooperates with a signal generator and a data acquisition device to realize the inspection and verification of the data acquisition device.

[0103] In another embodiment, for the device simulating an in-built charge amplifier type piezoelectric accelerometer, in addition to adjusting the equivalent resistance and / or equivalent capacitance by means of the DIP switch as described above, the present utility model also discloses a device for a programmable controlled in-built charge amplifier type piezoelectric accelerometer, which comprises an equivalent circuit, and the equivalent circuit comprises a digital potentiometer or a programmable resistance network, and a programmable capacitor array, and the equivalent resistance and equivalent capacitance of the equivalent circuit are dynamically adjusted by means of a microcontroller. It can be understood that this may increase the cost, but is conducive to providing a higher level of flexibility and automation, as well as higher precision and the implementation of more complex functions.

[0104] Exemplarily, the digital potentiometer is a multi-channel digital potentiometer, the programmable capacitor array is a variable capacitor, and the microcontroller is an Arduino or a Raspberry Pi, or other optional microcontrollers. Among them, the microcontroller automatically changes the equivalent resistance and equivalent capacitance of the equivalent circuit according to a preset sequence to implement equivalent circuits with different equivalent resistances and equivalent capacitances.

[0105] Similarly, for the device of this embodiment, the method for pre-adjusting the equivalent resistance and equivalent capacitance of the equivalent circuit as described above can also be implemented to ensure that the responses of the equivalent circuit at all key frequency points are kept within the allowable error range of the responses of a qualified accelerometer.

[0106] Further, the device, a signal generator and a data collector are formed into an inspection and calibration system for the data collector.

[0107] When the inspection and calibration system is operating, the following frequency response analysis method can be executed, which comprises the following steps:

[0108] The microcontroller starts from a setting of low impedance and low capacitance value, and gradually increases the equivalent resistance and equivalent capacitance of the equivalent circuit in the device, while the signal generator performs frequency sweeping;

[0109] The microcontroller further records the frequency response data under each setting and sends them to a computer through various interfaces such as a serial port or a network interface for real-time analysis and display;

[0110] Automatically compare the frequency response curves of the real accelerometer and the simulated data of the device.

[0111] Exemplarily, the resistance value is programmed to gradually increase from 1 kΩ to 10 kΩ, and the capacitance value is from 1 pF to 100 pF to generate a series of frequency response curves. If the frequency response errors of the real accelerometer to be inspected and calibrated are all within ±1 dB at all test points, it is determined to be qualified.

[0112] Furthermore, the system can also implement the method for determining the DC voltage and AC voltage described above: first determine whether the DC voltage on the equivalent resistor is within a normal range or an error range, and then check in the upper computer software of the data logger whether the measured AC voltage is generally consistent with the AC voltage provided by the signal generator or is within the error range.

[0113] Furthermore, in another embodiment, based on the above-mentioned programmable control device for simulating a piezoelectric accelerometer with built-in charge amplification, the utility model also discloses a method for evaluating the data acquisition device, comprising the following steps:

[0114] The software collects a large amount of frequency response data under different resistor and capacitor combinations, and uses data analysis and machine learning techniques to build a model that can predict the theoretical response curve under different settings to optimize the calibration algorithm. It can be understood that the data logger can use this model to perform real-time correction to improve measurement accuracy.

[0115] Use the optimized calibration algorithm to evaluate the performance of the data logger over the entire frequency band. For example, select several key frequency points (such as 100Hz, 1kHz, etc.) to check whether the measurement error of the data logger is within an acceptable range, and evaluate the linearity, sensitivity, and stability of the data logger by comparing it with the theoretical response curve.

[0116] In this way, the utility model can not only realize the above-mentioned inspection and verification but also can deeply evaluate and optimize the performance of the back-end data acquisition device after evaluation, so as to ensure its accuracy and reliability in various applications.

[0117] Furthermore, in another embodiment, the model includes:

[0118] Input layer: It contains two nodes, representing the logarithmic transformation of the resistance and capacitance values; this can better handle a wide range of values;

[0119] Hidden layers: two to three layers, each containing 8-16 neurons, using the ReLU activation function; this helps solve nonlinear problems;

[0120] Output layer: A single node that outputs the predicted frequency response value (e.g., attenuation in dB), using a linear activation function; this makes the output a continuous value.

[0121] Exemplarily, the model is built using Python's deep learning library such as TensorFlow or PyTorch.

[0122] It should be noted that the training method of the model includes the following steps:

[0123] Collect a dataset of a large number of different combinations of equivalent resistances and equivalent capacitances generated by the device. For example, the resistance values range from 1 kΩ to 10 kΩ with a step size of 1 kΩ; the capacitance values range from 1 pF to 100 nF with a step size of 10 pF. And for each set of resistance-capacitance values, use a signal generator to perform a frequency sweep in the range of 1 Hz to 1 kHz and record the response data.

[0124] Furthermore, perform normalization processing on the collected raw data to facilitate the learning of the neural network.

[0125] Furthermore, divide the dataset into a training set (e.g., 80% as the training set), a validation set (e.g., 10% as the validation set), and a test set (e.g., 10% as the test set). Then select the mean squared error (MSE) as the loss function and use the Adam optimizer for gradient descent.

[0126] Meanwhile, during the model training process, monitor the loss on the validation set to prevent overfitting. When the loss does not meet expectations or overfitting occurs, optimize the model through early stopping or model checkpoints, where

[0127] The method of optimizing the model using model checkpoints includes the following steps:

[0128] Before the start of the training loop, define a checkpoint callback function (such as the implementation of ModelCheckpoint in Keras), and specify the save path, file name format, and save conditions of the checkpoint. Exemplarily, common save conditions include saving at the end of each epoch or only when the validation loss improves.

[0129] Select one or more metrics (such as validation loss, accuracy) as the basis for triggering the save. When these metrics reach the optimal or improve, the state of the model will be automatically saved.

[0130] After training is completed, the training can be quickly resumed according to the saved checkpoints, avoiding loss of progress due to accidental interruption. At the same time, the model weights with the lowest validation loss (or the optimal value of other metrics) can be loaded as the final model deployment to ensure the optimal performance of the model.

[0131] Then evaluate the model performance on the test set. If the model has good generalization ability, the hyperparameters can be further fine-tuned to improve the prediction accuracy.

[0132] Although the embodiments of the present utility model have been described above in conjunction with the accompanying drawings, the present utility model is not limited to the above specific embodiments and application fields. The above specific embodiments are merely illustrative and guiding, rather than restrictive. Those of ordinary skill in the art can also make many forms under the inspiration of this specification and without departing from the scope protected by the claims of the present utility model, and all of these fall within the scope of protection of the present utility model.

Claims

1. A device for simulating a piezoelectric accelerometer with built-in charge amplification, characterized in that: include: Multiple capacitors, multiple resistors and multiple dip switches, among which, The DIP switch is capable of adjusting the connection relationship between some or all of the multiple resistors to form an equivalent resistor; The equivalent resistor and some or all of the capacitors in the plurality of capacitors form an equivalent resistor-capacitor circuit in which an equivalent resistor R and an equivalent capacitor C are connected in series, wherein: The equivalent resistance R in the equivalent resistance-capacitance circuit is equal to or approximately equal to the equivalent resistance of the built-in charge amplification type piezoelectric accelerometer. The equivalent capacitance C in the equivalent resistance-capacitance circuit is equal to or approximately equal to the equivalent capacitance of the piezoelectric accelerometer with built-in charge amplification.

2. The device according to claim 1, characterized in that The connection relationship of some or all of the resistors includes: series connection, parallel connection, or series-parallel connection to form a mixed connection.

3. The device according to claim 1, characterized in that The DIP switch can also adjust the connection relationship between some or all of the multiple capacitors to form an equivalent capacitor.

4. The device according to claim 3, characterized in that The connection relationship of some or all of the capacitors includes: series connection, parallel connection, or series-parallel connection to form a mixed connection.

5. The device according to claim 1, characterized in that The input end of the device is used to connect a signal generator.

6. The device according to claim 1, characterized in that The output end of the device is used to connect to a data acquisition device.

7. A calibration system for a data logger, characterized in that: include: A signal generator, and a device as claimed in any one of claims 1 to 6, and a data logger, wherein: The input end of the device is connected to a signal generator, and the output end of the device is connected to a data acquisition device.

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