Method for testing performance of acceleration sensor based on vibration table

Abstract

The application relates to the technical field of sensor vibration detection, and discloses a performance testing method of an acceleration sensor based on a vibration table, which simulates the modal of a vibration table surface, obtains a distribution pattern of the amplitude superposition of the vibration of the vibration table surface and the standing wave under different vibration frequencies through wave solution analysis, determines the point distribution position area with the optimal interference amplitude of the standing wave and the installation position of the acceleration sensor on the vibration table surface, generates an excitation signal through a signal generating unit, amplifies the excitation signal through a power amplifying unit, converts the excitation signal into a periodic signal for driving the vibration of a vibration generating unit, makes the sensor on the vibration table surface vibrate at a preset vibration amplitude and frequency, sends the signal generated due to the vibration to a signal conditioning unit to be converted into a signal recognizable by a control processing unit, and obtains the verification evaluation result of the acceleration sensor to be tested by the control processing unit.

Description

Technical Field

[0001] This invention relates to the field of sensor vibration detection technology, specifically to a performance testing method for an accelerometer based on a vibration table. Background Technology

[0002] Accelerometers are widely used in many industrial production fields such as consumer electronics, industrial automation, vehicle and aircraft safety, and structural monitoring. The quality of the accelerometer directly affects the results of the data collected in the current application scenario, and affects the correct operation of the entire device or system. Therefore, accurate measurement of accelerometer parameters has become a top priority in the field of detection technology.

[0003] In the testing and calibration of accelerometers, a vibrator is required. The vibrator can convert arbitrary periodic waveform signals generated by a signal generator into corresponding vibration frequencies by connecting a power amplifier, thereby driving the vibrator platform to vibrate.

[0004] During testing, the accelerometer is fixedly mounted on the vibration plane of the exciter. The results collected by the accelerometer are verified and compared with the data of the reference sensor to determine the quality of the sensor under test.

[0005] Currently, the main methods for testing the performance of accelerometer parameters are to provide stable acceleration excitation through vibration table vibration to simulate actual vibration conditions, and to use data loggers or oscilloscopes to collect and dynamically analyze test data in real time, or to use standard accelerometers as a benchmark to compare the performance of the test piece, thereby obtaining more accurate measurement data.

[0006] The testing and calibration of existing accelerometers do not initially specify the installation positions of the test piece and the reference sensor on the vibration table surface. According to the comparison of previous experimental data, it was found that different sensor installation positions have different effects on the experimental results. The relevant tests on the market have not been optimized for this, and there is a lack of measures specifically for accurately collecting vibration data and eliminating interference caused by different installation points. Summary of the Invention

[0007] To address the aforementioned shortcomings and deficiencies in the existing technology, this invention provides a performance testing method for an accelerometer based on a vibration table, comprising the following:

[0008] Step S1: Simulate the vibration table mode. Based on the shape of the table, the vibration table is regarded as a thin plate. Through wave solution analysis, the distribution of the vibration and standing wave amplitude superposition of the vibration table at different vibration frequencies in the target vibration frequency acquisition domain is obtained.

[0009] Step S2: Based on the results of Step 1, obtain the optimal distribution area of ​​each frequency affected by standing wave interference within the target vibration frequency acquisition domain, and determine the installation position of the accelerometer on the vibration table.

[0010] Step S3: An excitation signal is generated by the signal generation unit, amplified by the power amplification unit, and converted into a periodic signal that drives the vibration generation unit to vibrate at the same vibration frequency. This signal is then transmitted to the vibration generation unit, causing the accelerometer on the vibration table to vibrate according to the preset vibration amplitude and frequency.

[0011] Step S4: The accelerometer collects the IEPE signal generated by vibration and sends it to the signal conditioning unit. The signal conditioning unit converts the signal generated by the sensor into a signal that can be recognized by the control processing unit. The control processing unit then obtains the verification and evaluation results of the accelerometer under test.

[0012] In step S1, the target vibration frequency acquisition range for simulating the vibration table mode is 0.5Hz to 12KHz.

[0013] Step S1 is as follows:

[0014] Let w(x,y) be the amplitude of each coordinate point on the equivalent thin plate, which is composed of the superposition of several cosine waves, i.e., the expression for the solution in the X-axis direction:

[0015] ;

[0016] Where n is the number of peaks and troughs in the X-axis direction of the equivalent thin plate;

[0017] The expression for the solution in the Y-axis direction:

[0018] ;

[0019] Where m is the number of peaks and troughs in the Y-axis direction of the equivalent thin plate;

[0020] During vibration, the amplitude of w(x,y) is determined by the product of X(x) and Y(y), that is:

[0021] ;

[0022] When m and n take different values, the vibration frequency f varies with (m+2n). 2 Proportional to each other, we can obtain the possible distribution combinations of vibration amplitudes at different vibration frequencies.

[0023] Step S2 specifically involves: determining the frequency response range of the sensor under test, selecting several sets of vibration frequencies within this frequency response range, and selecting a total of 64 coordinate points in eight directions at each set of frequencies. Calculating the average amplitude value of these coordinate points and the difference between each coordinate point and the average amplitude, and obtaining the sensor installation position with the least interference at a single vibration frequency based on the results. At the same time, comparing the results of other sets of frequencies, the final installation position of the sensor is selected within the entire frequency response range.

[0024] In step S3, the signal generation unit is a signal generator. The output signal of the signal generator is sent to the power amplifier. After being amplified by the power amplifier, the signal is sent to the exciter. The exciter drives the accelerometer mounted on its vibration table to vibrate and sends the signal generated by the sensor through vibration, which includes parameters such as sensitivity, frequency response range, and range, to the signal conditioning unit.

[0025] In step S4, the signal conditioning module collects and summarizes the data from the accelerometer, conditions it, and sends it to the control processing unit for decoding or analysis. The signal conditioning module includes an ADC module, a DAC module, a digital input / output module, and an FPGA control module. The ADC module acquires analog signals, the DAC module outputs multi-channel signals synchronously, and the digital input / output module includes a buffered digital input / output and multiplexing function control module, which provides input / output signals for configuring digital signals, input / output signals for sampling clocks, digital trigger signals, or I / O signals for counters.

[0026] In step S4, the control processing unit is an industrial computer that analyzes and processes the collected sensor data, generates arbitrary vibration drive period signals as needed, detects the performance parameters of the sensor under test, including sensitivity, range, and linear range, based on the sensor data arranged at each location, and obtains the final evaluation result.

[0027] Compared with the prior art, the present invention has the following beneficial technical effects and advantages:

[0028] This invention performs vibration modal analysis on the vibration table surface of an exciter vibrating in the range of 0.5Hz to 12KHz. It eliminates the shortcomings of existing technologies that rely heavily on experience or blindly distribute sensors in a uniform manner, leading to missed modal detections. For the vibration table surface modes, based on its shape, the vibration table surface is treated as a thin plate. Through wave solution analysis, the distribution pattern of the vibration and standing wave amplitude superposition at different vibration frequencies within the target vibration frequency acquisition range of 0.5Hz to 12KHz is obtained. This reveals the optimal placement area for standing wave interference at each frequency within the target vibration frequency acquisition range, determining the installation position of the accelerometer on the vibration table surface. This effectively eliminates the interference of standing waves on the accelerometer data, significantly improving the accuracy and precision of the testing system and reducing testing costs. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the unit composition of the performance testing method for an accelerometer based on a vibration table according to the present invention;

[0030] Figure 2 For a vibration frequency of 1560Hz, step 1 yields the distribution combination pattern;

[0031] Figure 3 When the vibration frequency is 2340Hz, step 1 yields the distribution combination pattern. Detailed Implementation

[0032] The present invention will now be described in detail, as follows: Figure 1 As shown, the present invention provides a performance testing method for an accelerometer based on a vibration table, which is based on a signal generation unit, a power amplification unit, a vibration generation unit, a signal conditioning unit, and a control processing unit;

[0033] The signal generation unit includes the main body of the signal generator, power supply harness, and test signal harness. The overall frame of the signal generator is made of aluminum plate and PC material. The front panel has buttons, knobs, output interfaces, and a viewing window; the rear panel has the power interface and heat dissipation fins; and a handle is designed on the side. The panel is divided into functional areas, making operation simple and logically clear.

[0034] The power amplifier unit includes the main body of the power amplifier device, power supply harness, test signal harness, and feedback signal acquisition harness. The power amplifier adjusts the amplification factor of the output signal by using buttons and knobs, thereby adjusting the amplitude of the output signal. The output signal drives the exciter through the harness.

[0035] The vibration generating unit is an exciter, which converts the arbitrary periodic waveform signal generated by the signal generator into the corresponding vibration frequency through a power amplifier, thereby driving the platform of the exciter to vibrate. The sensor installation position on the vibration table is determined by algorithm calculation to select the position with the least interference to the collected signal and the optimal collection arrangement.

[0036] The signal conditioning unit collects and summarizes the data from the sensors, and sends it to the control processing unit for decoding or analysis after conditioning. The signal conditioning unit includes an ADC module, a DAC module, a digital input / output module, and an FPGA control module. The ADC module realizes the acquisition of analog signals, the DAC module realizes the synchronous output of multi-channel signals, and the digital input / output module includes a buffered digital input / output and multiplexing function control module, which provides input / output signals for configuring digital signals, input / output signals for sampling clocks, digital trigger signals, or I / O signals for counters.

[0037] The control and processing unit centrally analyzes and processes the collected sensor data and the working status of the test system components. The control and processing unit is an industrial control computer that can generate arbitrary vibration drive period signals according to experimental needs. It can detect performance parameters such as sensitivity, range, and linear range based on the sensors arranged on the vibration table and obtain the final evaluation results.

[0038] It also includes human-computer interaction devices such as monitors, keyboards, and mice, used to control and operate the experimental process.

[0039] Furthermore, the sensor installation position on the vibration table with the least interference in the acquired signal was selected, specifically as follows:

[0040] The vibration table mode was simulated. Based on the shape of the table, the vibration table was regarded as a thin plate. The distribution of the vibration and standing wave amplitude superposition of the vibration table at different vibration frequencies in the target vibration frequency acquisition range of 0.5Hz to 12KHz was obtained by wave solution analysis.

[0041] Let w(x,y) be the amplitude of each coordinate point on the equivalent thin plate, which is composed of the superposition of several cosine waves, i.e., the expression for the solution in the X-axis direction:

[0042] ;

[0043] Where n is the number of peaks and troughs in the X-axis direction of the equivalent thin plate;

[0044] The expression for the solution in the Y-axis direction:

[0045] ;

[0046] Where m is the number of peaks and troughs in the Y-axis direction of the equivalent thin plate;

[0047] During vibration, the amplitude of w(x,y) is determined by the product of X(x) and Y(y), that is:

[0048] ;

[0049] When m and n take different values, the vibration frequency f varies with (m+2n). 2 Proportional to each other, we can obtain the possible distribution combinations of vibration amplitudes at different vibration frequencies.

[0050] Specifically, when the vibration frequency is 1560Hz, the distribution combination pattern is as follows: Figure 2 As shown;

[0051] When the vibration frequency is 2340Hz, the distribution combination pattern is as follows: Figure 3 As shown;

[0052] By referring to the product manual, obtain the nominal frequency response range of the measured sensor, and select five groups of vibration frequencies that are roughly evenly distributed within this range.

[0053] For each of the five selected groups of vibration frequencies, with the center point of the image as the coordinate, select 64 coordinates in eight directions radiating like a "plus" sign, calculate the average amplitude value of these coordinates and the difference between each point and the average amplitude, and record the ten points with the smallest difference.

[0054] Finally, based on the results, the installation position of the sensor with the least interference under a single vibration frequency can be determined. By comparing the results of other groups of frequencies, the installation position of the sensor within the entire frequency response range can be finally selected.

[0055] After determining the installation position of the sensor on the vibration table, preset the vibration amplitude and vibration frequency, start the signal generator. The signal generator generates an excitation signal, which is amplified by the power amplifier and converted into a periodic signal that drives the exciter to vibrate at the same vibration frequency. The acceleration sensor on the exciter vibration table vibrates according to the preset vibration amplitude and frequency; the signal containing parameters such as sensitivity, frequency response range, and measurement range generated by the sensor through vibration is sent to the signal conditioning unit.

[0056] The signal conditioning unit converts the signal generated by the sensor into a signal recognizable by the control processing unit, and finally obtains the verification and evaluation result of the measured acceleration sensor.

[0057] Specifically, the acceleration sensor converts the charge signal generated by the vibrating piezoelectric crystal into a voltage signal through an internal impedance conversion circuit. After passing through the signal conditioning unit, the sensor is equivalent to a variable resistor and outputs a signal recognizable by the control processing unit. The control processing unit finally obtains the verification and evaluation result of the measured acceleration sensor.

[0058] For example, for the measurement of the sensor sensitivity, the measured sensor and the reference sensor collect data simultaneously in the same environment. Taking the data collected by the reference sensor as the standard, compare the deviation value measured by the measured sensor; select the average value of multiple measurement results under different vibration conditions as the final measurement value. If the final measurement value ≤ ±3%, it is judged as excellent (corresponding to 90 - 100 points according to the measured index), if the final measurement value ≤ ±5%, it is judged as qualified (corresponding to 60 - 89 points according to the measured index), and if the final measurement value > ±5%, it is judged as unqualified according to this scoring standard.

[0059] This invention performs vibration modal analysis on the vibration table surface of an exciter vibrating in the range of 0.5Hz to 12KHz. It eliminates the shortcomings of existing technologies that rely heavily on experience or blindly distribute sensors in a uniform manner, leading to missed modal detections. For the vibration table surface modes, based on its shape, the vibration table surface is treated as a thin plate. Through wave solution analysis, the distribution pattern of the vibration and standing wave amplitude superposition at different vibration frequencies within the target vibration frequency acquisition range of 0.5Hz to 12KHz is obtained. This reveals the optimal placement area for standing wave interference at each frequency within the target vibration frequency acquisition range, determining the installation position of the accelerometer on the vibration table surface. This effectively eliminates the interference of standing waves on the accelerometer data, significantly improving the accuracy and precision of the testing system and reducing testing costs.

[0060] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any modifications, alterations, substitutions, and variations made by those skilled in the art to the above embodiments are within the scope of the present invention.

[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A performance testing method for an accelerometer based on a vibration table, characterized in that, Includes the following steps: Step S1: Simulate the vibration table mode. Based on the shape of the table, the vibration table is regarded as a thin plate. Through wave solution analysis, the distribution of the vibration and standing wave amplitude superposition of the vibration table at different vibration frequencies in the target vibration frequency acquisition domain is obtained. Step S2: Based on the results of Step 1, obtain the optimal distribution area of ​​each frequency affected by standing wave interference within the target vibration frequency acquisition domain, and determine the installation position of the accelerometer on the vibration table. Step S3: An excitation signal is generated by the signal generation unit, amplified by the power amplification unit, and converted into a periodic signal that drives the vibration generation unit to vibrate at the same vibration frequency. This signal is then transmitted to the vibration generation unit, causing the accelerometer on the vibration table to vibrate according to the preset vibration amplitude and frequency. Step S4: The accelerometer collects the IEPE signal generated by vibration and sends it to the signal conditioning unit. The signal conditioning unit converts the signal generated by the sensor into a signal that can be recognized by the control processing unit. The control processing unit then obtains the verification and evaluation results of the accelerometer under test.

2. The performance testing method for an accelerometer based on a vibration table according to claim 1, characterized in that, In step S1, the target vibration frequency acquisition range for simulating the vibration table mode is 0.5Hz to 12KHz.

3. The performance testing method for an accelerometer based on a vibration table according to claim 1, characterized in that, Step S1 is as follows: Let w(x,y) be the amplitude of each coordinate point on the equivalent thin plate, which is composed of the superposition of several cosine waves, i.e., the expression for the solution in the X-axis direction: ； Where n is the number of peaks and troughs in the X-axis direction of the equivalent thin plate; The expression for the solution in the Y-axis direction: ； Where m is the number of peaks and troughs in the Y-axis direction of the equivalent thin plate; During vibration, the amplitude of w(x,y) is determined by the product of X(x) and Y(y), that is: ； When m and n take different values, the vibration frequency f varies with (m+2n). 2 Proportional to each other, we can obtain the possible distribution combinations of vibration amplitudes at different vibration frequencies.

4. The performance testing method for an accelerometer based on a vibration table according to claim 1, characterized in that, Step S2 specifically involves: determining the frequency response range of the sensor under test, selecting several sets of vibration frequencies within this frequency response range, and selecting a total of 64 coordinate points in eight directions at each set of frequencies. Calculating the average amplitude value of these coordinate points and the difference between each coordinate point and the average amplitude, and obtaining the sensor installation position with the least interference at a single vibration frequency based on the results. At the same time, comparing the results of other sets of frequencies, the final installation position of the sensor is selected within the entire frequency response range.

5. The performance testing method for an accelerometer based on a vibration table according to claim 1, characterized in that, In step S3, the signal generation unit is a signal generator. The output signal of the signal generator is sent to the power amplifier. After being amplified by the power amplifier, the signal is sent to the exciter. The exciter drives the accelerometer mounted on its vibration table to vibrate and sends the signal generated by the sensor through vibration, which includes parameters such as sensitivity, frequency response range, and range, to the signal conditioning unit.

6. The performance testing method for an accelerometer based on a vibration table according to claim 1, characterized in that, In step S4, the signal conditioning module collects and summarizes the data from the accelerometer, conditions it, and sends it to the control processing unit for decoding or analysis. The signal conditioning module includes an ADC module, a DAC module, a digital input / output module, and an FPGA control module. The ADC module acquires analog signals, the DAC module outputs multi-channel signals synchronously, and the digital input / output module includes a buffered digital input / output and multiplexing function control module, which provides input / output signals for configuring digital signals, input / output signals for sampling clocks, digital trigger signals, or I / O signals for counters.

7. The performance testing method for an accelerometer based on a vibration table according to claim 1, characterized in that, In step S4, the control processing unit is an industrial computer that analyzes and processes the collected sensor data, generates arbitrary vibration drive period signals as needed, detects the performance parameters of the sensor under test, including sensitivity, range, and linear range, based on the sensor data arranged at each location, and obtains the final evaluation result.

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