CN105891907A - Portable piezoelectric detector multi-parameter testing system and testing method - Google Patents

Abstract

The present invention relates to a portable piezoelectric detector multi-parameter testing system and testing method, comprising a piezoelectric detector to be tested, a sealed sound pressure chamber, a piezoelectric detector tester and a host computer; its technical features are: the piezoelectric detector The detector tester is composed of a shell and its internal measurement control circuit. The internal measurement control circuit includes: a microcomputer processor, an audio signal generation circuit, an audio power amplifier circuit, a signal excitation module, and a piezoelectric detector probe interface circuit to be tested. , signal processing and channel selection circuit, A/D converter and power supply module; the present invention analyzes various technical index parameters such as sensitivity, DC resistance, damping coefficient, natural frequency and polarity of the piezoelectric detector to be measured, It can fully reflect the performance of the piezoelectric detector to be tested.

Description

A portable piezoelectric detector multi-parameter testing system and testing method

technical field

The invention belongs to the technical field of piezoelectric detectors, in particular to a portable piezoelectric detector multi-parameter testing system and testing method.

Background technique

With the development of oil exploration from land to shallow sea and marsh areas, the market for piezoelectric detectors will gradually grow. Therefore, the demand for piezoelectric detector testers is becoming stronger and stronger.

The technical index of the piezoelectric geophone characterizes its role in the actual oil exploration construction, that is to say, the technical index parameters of the piezoelectric geophone will have a direct impact on the seismic exploration results. The measurement of the technical index parameters of the piezoelectric detector to be tested is realized through the piezoelectric detector test system, and the performance of a piezoelectric detector to be tested can be identified through the comparative analysis between the actual measured value and the designed nominal value However, the existing piezoelectric detector measurement system can measure a single technical index parameter of the piezoelectric detector. Generally, only two parameters of resistance and sensitivity can be measured, which cannot fully reflect the performance of the piezoelectric detector to be tested. inferior.

In addition, because the volume of the closed sound pressure chamber in the existing piezoelectric detector test system is too large, it cannot meet the field needs of oil exploration, so it cannot meet the current market demand.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art, and provide a portable piezoelectric detector multi-parameter testing system and testing method with reasonable design and comprehensive measurement of technical index parameters.

The present invention solves its technical problem and realizes by taking the following technical solutions:

A portable piezoelectric detector multi-parameter testing system, including a piezoelectric detector to be tested, a sealed sound pressure chamber, a piezoelectric detector tester and a host computer; the piezoelectric detector to be tested is installed on the top of the sealed sound pressure chamber and be connected with the piezoelectric detector probe interface to be tested of the piezoelectric detector tester; one end of the airtight sound cavity has a built-in speaker, and the speaker is connected with the audio signal output port of the piezoelectric detector tester; The piezoelectric detector tester is also connected with the host computer, and the sampling data is transmitted to the upper computer for calculation and analysis; the piezoelectric detector tester is composed of a casing and an internal measurement control circuit, and the internal measurement control The circuit includes: a microcomputer processor, an audio signal generating circuit, an audio power amplifier circuit, a signal excitation module, a probe interface circuit of a piezoelectric detector to be tested, a signal processing and channel selection circuit, an A/D converter and a power supply module; the microcomputer The processor is respectively connected with the audio signal generating circuit to control it to generate audio signals, connected with the audio power amplifier circuit to control its on-off, connected with the signal excitation module and outputting a DC control signal to it, and A/D conversion connected with the signal processing and channel selection circuit and output a channel selection control signal to it; the output end of the audio signal generation circuit is connected with the sound power amplifier circuit, and the output end of the sound power amplifier circuit is connected with the loudspeaker connection, used to make the speaker generate an external sound pressure excitation signal and then measure the sensitivity of the piezoelectric detector to be tested; the output end of the signal excitation module is connected to the probe interface circuit of the piezoelectric detector to be tested, and the piezoelectric detector to be tested The detector probe interface circuit is connected with the signal processing and channel selection circuit, and the output terminal of the signal processing and channel selection circuit is connected with the A/D converter for processing the response signal generated by the piezoelectric detector After amplification, filtering and impedance matching, it is output to the A/D converter; the power supply module is connected with the microcomputer processor and supplies power to each module of the measurement control circuit.

Moreover, the signal excitation module is composed of a DC voltage generating circuit and a pulse voltage generating circuit, the DC voltage generating circuit and the pulse voltage generating circuit include a D/A converter and a voltage follower, and the voltage follower is mainly composed of an operational amplifier Composition; the DC excitation signal generated by the DC voltage generation circuit is used to measure the DC resistance of the piezoelectric detector to be tested, and the pulse excitation signal generated by the pulse voltage generation circuit is used to measure the piezoelectric detector to be measured The damping coefficient and natural frequency of .

Moreover, the signal processing circuit of the signal processing and channel selection circuit includes two differential amplifiers with different amplification factors and an operational amplifier, and the differential amplifiers with two different amplification factors and the operational amplifier are connected together to form two The output voltage of the circuit follows the circuit to achieve the purpose of buffering and isolation.

Moreover, the channel selection circuit of the signal processing and channel selection circuit is composed of an analog switch and a relay, which is used for the external sound pressure excitation of the output DC excitation signal and pulse excitation signal of the signal excitation module and the output of the audio signal generation circuit. The signal is time-sharing on-off control.

Moreover, the microcomputer processor is also connected with one end of the extended liquid crystal screen interface circuit and the RS232 interface circuit, and the other end of the RS232 interface circuit is connected with the USB interface circuit, and is used for transferring the USB interface through the RS232 serial port. Communication with the upper computer in the common way.

Moreover, the airtight sound pressure chamber is a rigid cylinder with both ends sealed for simulating a uniform pressure field environment, and an electrodynamic low-frequency speaker is installed at one end of the rigid cylinder.

A test method for a portable piezoelectric detector multi-parameter test system, comprising the following steps:

Step 1. After connecting the piezoelectric detector tester with the host computer, calibrate the piezoelectric detector tester;

Step 2, testing the polarity of the piezoelectric detector to be tested;

Step 3. Install the piezoelectric detector to be tested after testing the polarity of the piezoelectric detector at a fixed position on the top of the sound pressure airtight chamber, and the sound pressure detector tester automatically measures the sensitivity, DC resistance, After the damping coefficient and natural frequency, the test result and test waveform will be displayed on the host computer software. If the test result does not meet the qualified range of the relevant manufacturer, the host computer software will display the corresponding indication;

Step 4, saving the test data of the piezoelectric detector to be tested and outputting a test report.

And, the concrete method of described step 1 is: first connect the piezoelectric detector tester with the communication interface of the host computer, then the host computer software sends a handshake signal to the piezoelectric detector tester, and the piezoelectric detector tester After receiving the handshake signal through the serial port, a reply signal is sent. If the sent reply signal matches the received handshake signal, the piezoelectric detector tester and the host computer have successfully shaken hands; The standard piezoelectric detector with known parameters is installed at a fixed position on the top of the airtight sound pressure chamber, and then the standard piezoelectric detector is connected to the test probe interface of the piezoelectric detector tester, and then the standard piezoelectric detector is input into the host computer. If the calibration is successful, the piezoelectric detector to be tested can be tested.

Moreover, the specific method of the step 2 is: the piezoelectric detector to be tested is connected to the test probe interface of the piezoelectric detector tester, and the host computer issues an instruction to test the polarity of the piezoelectric detector to be tested. After the sound of the speaker, press the sensitive part of the piezoelectric detector to be tested for a certain period of time, sample the response waveform output by the piezoelectric detector to be tested, and display it through the host computer, analyze the polarity of the first peak, if the first peak If it is a positive pulse, the piezoelectric detector under test is of positive polarity, and if it is a negative pulse, the piezoelectric detector under test is of negative polarity.

And, the specific method of described step 4 is: input the product number in the upper computer data recording area, click the record data button to save the current test data in the data recording area and input the tester name, product in the upper computer report information input box After numbering, click the report output button to output the previous test data in the data recording area in the form of a report.

Advantage and positive effect of the present invention are:

1. The present invention can fully reflect the performance of the piezoelectric detector to be tested by analyzing various technical index parameters such as sensitivity, DC resistance, damping coefficient, natural frequency, polarity, etc. of the piezoelectric detector to be tested.

2. The present invention adopts the airtight chamber comparison method when measuring the sensitivity of the detector to be tested. First, a relatively uniform sound field environment is established in a rigid airtight chamber, and the piezoelectric detector to be tested and the standard piezoelectric detector are time-shared. Into the same position in the cavity, respectively measure the open circuit voltage of the piezoelectric detector under a fixed sound pressure, because the open circuit voltage of the standard piezoelectric detector will not change much under the same environment. The piezoelectric detector multi-parameter test system can record the open-circuit voltage of the standard piezoelectric detector in this period, and provide comparison parameters for subsequent continuous measurement of multiple groups of piezoelectric detectors to be tested. The method for measuring the sensitivity of the detector to be tested in the present invention can The volume of the closed sound pressure cavity is saved, and the portability of the instrument is greatly improved.

Description of drawings

Fig. 1 is an overall structural block diagram of the present invention;

Fig. 2 is the internal measurement control circuit block diagram of the piezoelectric detector tester of the present invention;

Fig. 3 is the generation circuit of DC voltage and pulse voltage of the present invention;

Fig. 4 is a schematic block diagram of the airtight sound pressure cavity signal source of the present invention;

Fig. 5 is a schematic diagram of a response signal processing circuit of the present invention;

Fig. 6 is a structural schematic diagram of a closed sound pressure chamber of the present invention;

Fig. 7 is the organizational relationship diagram of the upper computer function of the present invention;

Fig. 8 is the test program processing flow chart of upper computer of the present invention;

Fig. 9 is the processing flow chart of the report generation program of the host computer of the present invention;

Fig. 10 is a physical installation diagram of the present invention.

Explanation of reference signs:

1- Piezoelectric detector to be tested; 2- Sealed sound pressure cavity; 3- Speaker

detailed description

A portable piezoelectric detector multi-parameter testing system, as shown in Figure 10, includes a piezoelectric detector to be tested, a closed sound pressure chamber, a piezoelectric detector tester, a host computer and a printer; the piezoelectric detector to be tested The detector is installed on the top of the closed sound pressure chamber and connected with the piezoelectric detector probe interface to be tested of the piezoelectric detector tester; one end of the sealed sound cavity has a built-in speaker, and the loudspeaker is connected to the piezoelectric detector tester The audio signal output port is connected; the piezoelectric detector tester is also connected with the host computer, and the sampling data is transmitted to the host computer for calculation and analysis; the host computer system is a host computer software developed based on the Windows system. The software can analyze and calculate the sampling data of the lower computer, display, save and print the test results and corresponding test waveforms; the upper computer is also connected to a printer for printing the test data report of the piezoelectric detector to be tested.

The airtight sound pressure chamber is used to simulate a uniform pressure field environment, and its structure is shown in Figure 6. The airtight sound pressure wall is a rigid cylinder with both ends sealed, and an electric low-frequency speaker is installed at one end of the rigid cylinder.

The piezoelectric detector tester is composed of a shell and an internal measurement control circuit, and the internal measurement control circuit includes a microcomputer processor, an audio signal generation circuit, an audio power amplifier circuit, a signal excitation module, The probe interface circuit of the piezoelectric detector to be tested, the signal processing and channel selection circuit, the A/D converter, the extended LCD screen interface circuit, the RS232 interface circuit, the USB interface circuit and the power supply module; The generating circuit is connected to control it to generate audio signals, connected to the audio power amplifier circuit to control its on-off, connected to the signal excitation module and output a DC control signal to it, connected to the A/D converter, and connected to the signal The processing is connected with the channel selection circuit and outputs a channel selection control signal to it; the output end of the audio signal generation circuit is connected with the audio power amplifier circuit, and the output end of the sound power amplifier circuit is connected with the loudspeaker for making the loudspeaker Generate an external sound pressure excitation signal and then measure the sensitivity of the piezoelectric detector to be tested; the output end of the signal excitation module is connected to the probe interface circuit of the piezoelectric detector to be tested, and the probe interface circuit of the piezoelectric detector to be tested is connected to the The signal processing and channel selection circuit is connected, and the output terminal of the signal processing and channel selection circuit is connected with the A/D converter for amplifying, filtering and impedance matching the corresponding signal generated by the piezoelectric detector Output to the A/D converter; the microcomputer processor is also connected with one end of the extended LCD interface circuit and the RS232 interface circuit respectively, and the other end of the RS232 interface circuit is connected with the USB interface circuit for passing through the RS232 serial port The communication mode of turning to the USB interface communicates with the host computer; the power supply module is connected with the microcomputer processor and supplies power for each module of the measurement control circuit.

The working principles and functions of the audio generation circuit, signal excitation module, signal processing and channel selection circuit in the measurement control circuit are described below:

(1) Audio generating circuit: the audio signal produced by the audio generating circuit of the present embodiment is based on direct numerical frequency synthesis (DDS), adopting the DDS chip of AD9833 to produce the required 31.5HZ of the piezoelectric detector tester Sine waveform. As shown in Figure 4, the sine wave signal is amplified by the TDA7492 power amplifier board to drive the speaker in the closed sound pressure chamber to form an external sound pressure excitation signal, and then measure the sensitivity of the piezoelectric detector to be tested. Its function is to make the loudspeaker generate an external sound pressure excitation signal, and then measure the sensitivity of the piezoelectric detector to be tested.

(2) Signal excitation module: the signal excitation module of the present embodiment, as shown in Figure 3, is made up of DC voltage generation circuit and pulse voltage generation circuit, and described DC voltage generation circuit and pulse voltage generation circuit comprise D/A converter and A voltage follower, the voltage follower is mainly composed of an operational amplifier; the D/A converter adopts a D/A converter chip whose model is DAC8562, and the operational amplifier adopts a precision operational amplifier chip whose model is OPA2111. Its function is: the DC excitation signal generated by the DC voltage generation circuit is used to measure the DC resistance of the piezoelectric detector to be tested, and the pulse excitation signal generated by the pulse voltage generation circuit is used to measure the piezoelectric detector to be tested. The damping coefficient and natural frequency of .

(3) Channel selection circuit: the channel selection circuit of the present embodiment is made of analog switch and relay, because there are three kinds of excitations when the piezoelectric detector to be measured is tested, it is the DC excitation when measuring resistance respectively; Pulse excitation; external sound pressure excitation when measuring sensitivity. Various excitation signals act independently on the piezoelectric detector to be tested, so it is necessary for the channel selection circuit to excite the DC excitation signal and the pulse excitation signal output by the signal excitation module and the external sound pressure excitation output by the audio signal generation circuit The signal is time-sharing on-off control. The analog switch in this embodiment is a high-speed analog switch ADG1436. With the cooperation of the high-speed analog switch and the relay, the time-sharing on-off control of various excitation signals is completed. The external sound pressure excitation is used to measure the sensitivity of the piezoelectric detector to be tested, the DC voltage excitation is used to measure the transformer coil resistance of the piezoelectric detector to be tested, and the pulse voltage excitation is used to measure the piezoelectric detector to be tested The damping coefficient and natural frequency of .

(4) Signal processing circuit: the signal processing circuit of the present embodiment as shown in Figure 5, comprises the differential amplifier of two different amplification factors and an operational amplifier, the differential amplifier of the two different amplification factors and the operational amplifier The amplifiers are connected together to form a voltage follower circuit with two outputs for buffering and isolation purposes. After the excitation signal is output to the piezoelectric detector, the piezoelectric detector generates a corresponding response signal, which needs to be processed before the response signal is input to the A/D converter channel. The main function of the signal processing circuit is to amplify and filter the response signal and perform impedance matching. Its working principle is: since the front-end circuit of the A/D converter needs different magnifications when measuring the polarity, resistance, damping coefficient, natural frequency and sensitivity of the piezoelectric detector to be tested, in order to improve the A/D The sampling accuracy of the converter adopts two differential amplifiers with different amplification factors respectively. The signal processing of the present invention adopts INA128 differential amplifier chip, which can filter common mode interference and perform differential amplification. The output of the differential amplifier adopts a first-order low-pass filter, which can eliminate high-frequency interference existing in the response signal. Then, the two output voltage follower circuits are composed of operational amplifiers, which play the role of buffering and isolation. The operational amplifier of the signal processing circuit of the present invention adopts the OPA2211 operational amplifier chip.

The gain of the differential amplifier chip INA128 is:

$\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 50</span>}\mathrm{<span\; class="notranslate">\; K</span>}}{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 9</span>}<span\; class="notranslate">\; )</span>$

Wherein, R _F =10K, R _F =NC (no connection), it can be known that the amplification factors of the two amplified signals are 6 times and 1 times.

The power supply module is a ±12V/±5V/3.3V DC power supply module; the microcomputer processor adopts the minimum system module chip of a low-power single-chip microcomputer MSP430F5438a; the A/D converter adopts 18-bit high-precision charge redistribution successively Approximate high-speed analog-to-digital converter AD7634 chip; the serial communication circuit adopts the MAX3232 chip to form the serial communication circuit; the USB interface circuit adopts the ZE533C type USB-to-serial data link line.

A test method for a portable piezoelectric detector multi-parameter test system, comprising the following steps:

Step 1. After connecting the piezoelectric detector tester with the host computer, calibrate the piezoelectric detector tester. The concrete method of described step 1 is: first connect the piezoelectric detector tester with the communication interface of the host computer, then the host computer software sends a handshake signal to the piezoelectric detector tester, and the piezoelectric detector tester passes the serial port After receiving the handshake signal, send a reply signal. If the sent reply signal matches the received handshake signal, the piezoelectric detector tester and the host computer have successfully shaken hands; The standard piezoelectric detector of the parameters is installed at a fixed position on the top of the airtight sound pressure chamber, and then the standard piezoelectric detector is connected to the test probe interface of the piezoelectric detector tester, and then the standard piezoelectric detector is input into the host computer. Technical index parameters, turn on the automatic calibration function of the instrument, if the calibration is successful, you can test the piezoelectric detector to be tested.

Step 2. Test the polarity of the piezoelectric detector to be tested. The specific method of said step 2 is: the piezoelectric detector to be tested is connected to the test probe interface of the piezoelectric detector tester, and the host computer sends an instruction to test the polarity of the piezoelectric detector to be tested. After the sound, press the sensitive part of the piezoelectric detector to be tested for a certain period of time, sample the response waveform output by the piezoelectric detector to be tested, and display it through the host computer, analyze the polarity of the first peak, if the first peak is a positive pulse Then the piezoelectric detector under test is of positive polarity, and if it is a negative pulse, the piezoelectric detector under test is of negative polarity.

Step 3. Install the piezoelectric detector to be tested after testing the polarity of the piezoelectric detector at a fixed position on the top of the sound pressure airtight chamber, and the sound pressure detector tester automatically measures the sensitivity, DC resistance, After the damping coefficient and natural frequency, the test result and test waveform will be displayed on the host computer software. If the test result does not meet the qualified range of the relevant manufacturer, the host computer software will display the corresponding indication;

Step 4, saving the test data of the piezoelectric detector to be tested and outputting a test report. The specific method of said step 4 is: input the product number in the upper computer data recording area, click the record data button to save the current test data in the data recording area after inputting the tester's name and product number in the upper computer report information input box Click the report output button to output the previous test data in the data recording area in the form of a report.

The method for automatically measuring the sensitivity, DC resistance, damping coefficient and natural frequency of the piezoelectric detector to be tested by using the sound pressure detector tester in step 3 is described in detail below:

(1) Test the sensitivity of the tested piezoelectric detector

According to GB4130-84, the calibration method for the sensitivity of the piezoelectric detector with a frequency within 1Hz to 3.15KHz can be divided into a primary calibration method and a secondary calibration method according to the calibration accuracy. Among them, the purpose of the primary calibration is to calibrate the standard piezoelectric sensor, and the purpose of the secondary calibration is to calibrate the piezoelectric detector to be tested. Generally, the main methods for calibrating the piezoelectric detector to be tested include the vibrating liquid column method and the closed sound pressure chamber comparison method. Because the airtight sound pressure chamber comparison method has the advantages of simple device, easy to carry, convenient calibration, high calibration accuracy and strong applicability of the piezoelectric detector test frequency, the sensitivity of the piezoelectric detector to be measured by the airtight sound pressure chamber comparison method is selected in the present invention. carry out testing.

The test principle of the airtight chamber comparison method is shown in Figure 1. First, a relatively uniform sound field environment is established in a rigid airtight chamber, and the piezoelectric detector to be tested and the standard piezoelectric detector are placed in the chamber at the same time. The open circuit voltage of the piezoelectric detector under a fixed sound pressure is measured separately, because the open circuit voltage of the standard piezoelectric detector will not change much under the same environment. The piezoelectric detector multi-parameter test system can record the open-circuit voltage of the standard piezoelectric detector in this period, and provide comparison parameters for subsequent continuous measurement of multiple groups of piezoelectric detectors to be tested. The method for measuring the sensitivity of the detector to be tested in the present invention can The volume of the closed sound pressure cavity is saved, and the portability of the instrument is greatly improved.

The formula for calculating the sound pressure sensitivity of the piezoelectric detector to be tested is:

${\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}}}{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

In the above formula, Mx is the sound pressure sensitivity of the piezoelectric detector to be tested (μV/μPa); Ms is the sound pressure sensitivity of the standard piezoelectric detector (μV/μPa); Ux is the open circuit voltage at the output of the piezoelectric detector to be tested (μV); Us is the open-circuit voltage (μV) at the output of the standard piezoelectric detector.

When measuring the sensitivity of the piezoelectric detector to be tested, the signal processing and channel selection circuit selects the corresponding sensitivity measurement channel, and the microcomputer processor controls the audio signal generation circuit to generate an audio signal (DDS sine wave signal), and the DDS sine wave signal The power is amplified through the audio power amplifier circuit, and the speaker in the closed sound pressure cavity is pushed to form an external sound pressure excitation signal in the closed sound pressure cavity. The speaker makes a sound, which stimulates the output response of the piezoelectric detector to be tested, and the A/D converter samples the test. The output response of the piezoelectric detector is transmitted to the host computer through the serial port to USB module for calculation and analysis.

(2) Test the damping coefficient and natural frequency of the measured piezoelectric detector

The signal processing and channel selection circuit selects the damping coefficient and the natural frequency measurement channel, the microcomputer processor controls the audio power amplifier circuit to be disconnected, and the speaker stops sounding; the microcomputer processor controls the signal excitation module to generate a pulse excitation signal to excite the output of the piezoelectric detector to be tested In response, the A/D converter samples the output response of the piezoelectric detector to be tested, and transmits it to the host computer through the serial port to USB module for calculation and analysis.

The specific test process is: the channel selection circuit of the microcomputer processor switches the analog switch to the channel for measuring the damping coefficient and the natural frequency, and the DC excitation voltage generated by the D/A converter is about 1.4V. , the analog switch disconnects the excitation voltage, so that the second-order circuit composed of the piezoelectric ceramic sheet of the piezoelectric detector and the transformer coil undergoes RLC oscillation, and at the same time, the A/D sampler is turned on to collect the response waveform, and the computer will calculate the The two parameters of damping coefficient and natural frequency are obtained.

According to the structural analysis of the piezoelectric detector to be tested, it can be concluded that the mechanical structure of the piezoelectric detector is a second-order mechanical system model, so the method adopted is the DC excitation method, that is, the output response of the sampling detector under the DC excitation Correlation operations. Its motion equation and output equation are:

$\left\{\begin{array}{c}\mathrm{<span\; class="notranslate">\; m</span>}\stackrel{<span\; class="notranslate">\; \&CenterDot;\&CenterDot;</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; c</span>}\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; k</span>}\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; e</span>}}{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}<span\; class="notranslate">\; (</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>\\ \mathrm{<span\; class="notranslate">\; e</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; e</span>}}\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

In the above formula, t≥0 is the zero input response time; m is the mass of the piezoelectric ceramic sheet of the piezoelectric detector; ε(-t) is a unit step function, when t≤0, ε(-t)=1, When t≥0, ε(-t)=0; c is the damping coefficient of the piezoelectric detector; k is the combined stiffness of the piezoelectric detector; c _me is the sensitivity of the piezoelectric detector; x is the deformation of the piezoelectric ceramic displacement; I ₀ is the amplitude of the excitation current; e(t) is the time-domain response function of the DC excitation; is the second partial derivative of x; is the first partial derivative of x.

From the above formula (2), the output equation of the piezoelectric detector to be tested can be deduced as:

$\mathrm{<span\; class="notranslate">\; e</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\frac{{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; e</span>}}{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}{\mathrm{<span\; class="notranslate">\; m</span>}}\frac{{\mathrm{<span\; class="notranslate">\; e</span>}}^{{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}\mathrm{<span\; class="notranslate">\; t</span>}}}{{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}}\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

In the above formula, m is the quality of the piezoelectric ceramic sheet of the piezoelectric detector to be tested; c _me is the sensitivity of the piezoelectric detector; I ₀ is the current value added to both ends of the piezoelectric detector; B _t is the Relative damping coefficient; ω ₀ is the inherent angular frequency of the piezoelectric detector; e is a natural constant.

A ₁ and A ₂ in the DC excitation response curve of the piezoelectric detector represent the amplitudes of the first peak and the second trough respectively, and by deriving formula (3) and setting e′(t)=0, we can get The following formula:

$\frac{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; exp</span>}<span\; class="notranslate">\; (</span><span\; class="notranslate">\; -</span>\frac{{\mathrm{<span\; class="notranslate">\; \&pi;B</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}}{\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

Among them, exp is an exponential function with the natural constant e as the base.

By further simplifying Equation (4), the relative damping coefficient of the hydrophone can be obtained as:

${\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; ln</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}{\sqrt{{\mathrm{<span\; class="notranslate">\; \&pi;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; ln</span>}\frac{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

For the natural frequency F _n , T is the time between the starting point of the DC excitation response curve and the first zero-crossing point, let e(T)=0, we can get Since T is the time when zero passes for the first time, it can be obtained that It can be seen that the calculation formula of the natural frequency F _n is:

${\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span>$

Derived from the above analysis, we obtained the parameter calculation method of the damping coefficient and natural frequency of the hydrophone. Through formulas (5) and (6) and the DC excitation response curve of the piezoelectric detector, after collecting the DC excitation response of the hydrophone , we can easily calculate the damping and natural frequency of the hydrophone by extracting the three data information of T, A ₁ and A ₂ .

(3) Test the DC resistance of the piezoelectric detector under test

The signal processing and channel selection circuit selects the DC resistance measurement channel, adjusts the excitation voltage of the D/A converter in the signal excitation module, the microcomputer processor controls the audio power amplifier circuit to disconnect, and the speaker stops sounding; the microcomputer processor controls the signal excitation module to generate The stable DC voltage excitation signal stimulates the output response of the piezoelectric detector to be tested, and the A/D converter samples the output response of the piezoelectric detector to be tested, and transmits it to the host computer through the serial port to USB module for calculation and analysis.

In this embodiment, the constant voltage method is used to measure the resistance, and the voltage of the untested piezoelectric detector is first collected, that is, the voltage U of the constant voltage source when the circuit is open; then the analog switch is switched to connect the piezoelectric detector to be tested into the circuit, The voltage u at both ends of the piezoelectric detector is collected. Since the known resistance in the circuit is a precision resistor, its resistance value is r, so the DC resistance R of the piezoelectric detector can be obtained very easily. The calculation formula is:

$\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; u</span>}}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; )</span>$

Simplify formula (7) to get:

$\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; r</span>}}{\frac{\mathrm{<span\; class="notranslate">\; u</span>}}{\mathrm{<span\; class="notranslate">\; u</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 8</span>}<span\; class="notranslate">\; )</span>$

In this embodiment, the organizational relationship of the functions of the host computer is shown in Figure 7. The functions of the host computer are mainly reflected in the form of the man-machine interface. The man-machine interface is the user's operation interface, which can completely reflect the tester Function, use this interface as a framework to add corresponding algorithm programs to complete specific test functions. The main interface of the tester mainly includes: serial port configuration, test value display area, test threshold indication, calibration settings, data recording area, and report generation settings.

In this embodiment, the process flow of the host computer is shown in Figure 8 and Figure 9. After starting the host computer software, it is first necessary to initialize the relevant settings, mainly including serial port initialization, calibration of the host computer, etc. The program mainly includes two parts: the first part mainly processes the relevant test data sent by the serial port, displays the test value and test waveform, and analyzes and judges the test results. The second part is to save multiple sets of test results and generate corresponding test reports according to user requirements. After initializing the upper computer, send a test command, the serial port monitor starts to work, and an interrupt is generated when the buffer characters reach the set value. After reading the data packet sent by the serial port, send a message to the corresponding message processing function for data processing and analysis, and then display it on the interface. If there is a need to save the data, the data can be saved in the data storage area, and the test report can be generated after filling in the user information.

It should be emphasized that the embodiments described in the present invention are illustrative rather than restrictive, so the present invention includes and is not limited to the embodiments described in the specific implementation, and those skilled in the art according to the technology of the present invention Other implementations derived from the scheme also belong to the protection scope of the present invention.

Claims (10)

1. a handheld piezoelectric cymoscope Multi parameters Test Macro, including piezoelectricity detection to be measured Device, airtight acoustic pressure chamber, hydrophone tester and host computer；It is characterized in that: described in treat Survey piezoelectric seismometer be arranged on airtight acoustic pressure top of chamber and with described hydrophone tester Piezoelectric seismometer probe interface to be measured is connected；One end boombox of the described airtight operatic tunes, This speaker is connected with the audio signal delivery outlet of described hydrophone tester；This piezoelectricity Geophone tester is also connected with host computer, and to host computer, sampled data transmission is carried out computing Analyze；Described hydrophone tester is made up of the circuit of measurement and control of shell and inside thereof, The circuit of measurement and control of described inside includes: computer processor, audio signal generating circuit, sound Ring at power amplifier, signal stimulating module, piezoelectric seismometer probe interface circuit to be measured, signal Reason and channel selection circuit, A/D converter and power supply module；Described computer processor divides It is not connected for controlling its generation audio signal with audio signal generating circuit, with sound equipment power amplifier Circuit is connected for controlling its break-make, is connected with signal stimulating module and exports direct current to it Control signal, is connected with A/D converter, is connected with signal processing and channel selection circuit And select control signal to its output channel；The outfan of described audio signal generating circuit and sound Ringing power amplifier to be connected, the outfan of this sound power amplifier is connected with described speaker, uses Produce external sound pressure pumping signal in making speaker and then measure the sensitive of piezoelectric seismometer to be measured Degree；The outfan of described signal stimulating module is connected with piezoelectric seismometer probe interface circuit to be measured Connect, described piezoelectric seismometer probe interface circuit to be measured and signal processing and channel selection circuit phase Connecting, described signal processing is connected with described A/D converter with the outfan of channel selection circuit Connect the response signal for being produced by described piezoelectric seismometer and be amplified filtering and impedance matching Rear output is to A/D converter；Described power supply module is connected also with described computer processor Modules for circuit of measurement and control is powered.

A kind of handheld piezoelectric the most according to claim 1 cymoscope multi-parameters test system System, it is characterised in that: described signal stimulating module is by DC voltage generation circuit and pulse voltage Generation circuit forms, and described DC voltage generation circuit and pulse voltage produce circuit and include D/A Transducer and voltage follower, described voltage follower is mainly made up of operational amplifier；Described The continuous current excitation signal that DC voltage generation circuit produces is used for measuring described piezoelectricity detection to be measured The D.C. resistance of device, described pulse voltage produces the pulse excitation signal of circuit generation and is used for measuring The damped coefficient of described piezoelectric seismometer to be measured and natural frequency.

A kind of handheld piezoelectric cymoscope multiparameter the most according to claim 1 and 2 is surveyed Test system, it is characterised in that: described signal processing and the signal processing circuit of channel selection circuit Including differential amplifier and an operational amplifier of two different amplification coefficients, said two is not Defeated with the differential amplifier of amplification coefficient and the described operational amplifier composition two-way that links together The voltage follower circuit gone out, it is achieved the purpose buffering and isolating.

A kind of handheld piezoelectric cymoscope multiparameter the most according to claim 1 and 2 is surveyed Test system, it is characterised in that: described signal processing and the channel selection circuit of channel selection circuit Being made up of analog switch and relay, the direct current for the output to described signal stimulating module swashs Encourage the external sound pressure excitation of signal and pulse excitation signal and audio signal generating circuit output Signal carries out timesharing break-make control.

A kind of handheld piezoelectric cymoscope multiparameter the most according to claim 1 and 2 is surveyed Test system, it is characterised in that: described computer processor the most respectively with extension LCD Interface circuit Be connected with one end of RS232 interface circuit, the other end of described RS232 interface circuit with Usb circuit is connected, for the current side for being turned USB interface by RS232 serial ports Formula communicates with host computer.

A kind of handheld piezoelectric cymoscope multiparameter the most according to claim 1 and 2 is surveyed Test system, it is characterised in that: described airtight acoustic pressure chamber is for simulating uniform pressure field environment The rigidity drum that two ends are airtight, electrodynamic type woofer is installed in one end of described rigidity drum.

7. a kind of handheld piezoelectric cymoscope as described in any one of claim 1-6 is many The method of testing of parameter test system, it is characterised in that comprise the following steps:

Step 1, hydrophone tester is shaken hands with host computer be connected after to piezoelectric seismometer Tester is calibrated；

Step 2, test the polarity of piezoelectric seismometer to be measured；

Step 3, the piezoelectric seismometer to be measured testing piezoelectric seismometer polarity is arranged on acoustic pressure The fixed position at closed chamber top, acoustic pressure geophone tester measures piezoelectric seismometer to be measured automatically Sensitivity, D.C. resistance, damped coefficient and natural frequency after on upper computer software display should Test result and test waveform, if test result does not meets relevant manufacturing firm acceptability limit, on Position machine software can show corresponding instruction；

Step 4, preserve the test data of piezoelectric seismometer to be measured and export testing journal sheet.

A kind of handheld piezoelectric the most according to claim 7 cymoscope multi-parameters test system The method of testing of system, it is characterised in that: described step 1 method particularly includes: first by piezoelectricity Geophone tester is connected with the communication interface of host computer, and then upper computer software is to this piezoelectricity Geophone tester sends handshake, and hydrophone tester receives this by serial ports and holds Complex signal is sent back after hands signal, if the return signal sent is consistent with the handshake of reception, Then hydrophone tester and host computer are shaken hands successfully；Hydrophone tester and host computer After shaking hands successfully, the standard piezoelectric cymoscope of known parameters is arranged on airtight acoustic pressure top of chamber By the test probe interface of standard piezoelectric cymoscope Yu hydrophone tester behind fixed position It is connected, then inputs the technical specification parameter of this standard piezoelectric cymoscope at host computer, open Instrument automatic calibration function, if calibrating successfully, can test piezoelectric seismometer to be measured.

9. survey according to a kind of handheld piezoelectric cymoscope multiparameter described in claim 7 or 8 The method of testing of test system, it is characterised in that: described step 2 method particularly includes: by be measured Piezoelectric seismometer is connected with the test probe interface of hydrophone tester, and host computer sends Test the instruction of piezoelectric seismometer polarity to be measured, when after the sound hearing speaker, pressure measurement is treated in pressing The sensitive part certain time of electricity cymoscope, the response wave shape of piezoelectric seismometer to be measured of sampling output, And shown by host computer, analyze the polarity of first crest, if first crest is The most tested piezoelectric seismometer of positive pulse is positive polarity, if the most tested piezoelectric seismometer of negative pulse For negative polarity.

10. survey according to a kind of handheld piezoelectric cymoscope multiparameter described in claim 7 or 8 The method of testing of test system, it is characterised in that: described step 4 method particularly includes: upper Machine data recording area input product is numbered, and clicks record data button by current test data It is saved in after data recording area at host computer report messages input frame input test people's name, product Clicking report output button after product numbering then can be by the successive test data of data recording area Report form output.