Frequency-response function measurement method employing pulse-like excitation

A technology of pulse excitation and frequency response function, which can be used in measurement devices, testing of machine/structural components, vibration testing, etc., and can solve problems such as frequency confusion.

Active Publication Date: 2016-01-13
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] During the digital sampling process of the signal, due to the co-occurrence signal in the sampled analog signal, it is easy to cause frequency confusion

Method used

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  • Frequency-response function measurement method employing pulse-like excitation
  • Frequency-response function measurement method employing pulse-like excitation
  • Frequency-response function measurement method employing pulse-like excitation

Examples

Experimental program
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Embodiment 1

[0081] The measuring system that embodiment 1 adopts is as figure 2 As shown, the measurement system is composed of conventional equipment, including NI data collectors, power supplies, anti-aliasing filters, computers, etc. Use a computer to make a pulse-like excitation signal, which is input to the anti-aliasing filter through the NI data collector, and at the same time use the data collector to collect the input signal x(t) and output signal y(t) of the anti-aliasing filter, In the computer, the signal processing of the input and output signals of the anti-aliasing filter and the calculation of the frequency response function are programmed according to the method of the present invention.

[0082] The specific measurement process of embodiment 1 is as figure 1 As shown, the specific steps are as follows:

[0083] 1) Determine the frequency range of the system under test:

[0084] In embodiment 1, the frequency range is [10Hz, 1500Hz]

[0085] 2) Design pulse excitation ...

Embodiment 2

[0110] The measuring system that embodiment 2 adopts is as Figure 4 As shown, the measurement system is composed of conventional equipment, including NI data collectors, acceleration sensors, piezoelectric ceramic strain gauges, power supplies, cantilever beams, computers, etc. Use the computer to make a pulse-like excitation signal, and input it into the piezoelectric ceramic strain gauge through the NI data collector. The strain gauge provides a pulse-like excitation to the cantilever beam at the fixed end of the cantilever beam. The acceleration sensor is installed at the cantilever end of the cantilever beam. The data collector collects the input signal x(t) of the fixed end and the output signal y(t) of the cantilever end, and performs signal processing of the input signal and output signal and calculation of the system frequency response function by programming in the computer according to the method of the present invention.

[0111] The specific measurement process of...

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Abstract

The invention relates to a frequency-response function measurement method employing pulse-like excitation, and belongs to the technical field of electric system and mechanical system frequency-response function measurement. The method comprises the steps: determining a frequency range; constructing a pulse-like excitation signal as an input signal of a measured system; measuring the input signal of the measured system and an output signal of the measured system; carrying out the windowing Fourier transform of the input and output signals of the measured system through employing a central zero window analysis method, and obtaining a windowed Nyquist frequency spectrum; employing the windowed Nyquist frequency spectrum for calculation, and obtaining the frequency-response function of the measured system. The method can achieve the quick measurement of the frequency-response function. Moreover, the method can obtain high precision which is difficult to achieve through other methods the frequency-response function of a strong resonance system is measured.

Description

technical field [0001] The invention belongs to the technical field of measuring frequency response functions of electrical systems and mechanical systems, and in particular relates to efficient measurement of frequency response functions of expected frequency bands and accurate measurement of strong resonance frequency response functions. Background technique [0002] The frequency response function of the system is the ratio of the response (output) signal spectrum function of the system to the excitation (input) signal spectrum function, which can reflect the dynamic / electrical characteristics of the system within the frequency range. The frequency response function method is one of the most important means of measuring the characteristics of mechanical and electrical systems. After the Fast Fourier Transform (FFT) method appeared, in order to improve the measurement efficiency, people widely used broadband excitation. For a system, waveform distortion, energy leakage, a...

Claims

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Application Information

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IPC IPC(8): G01R23/16G01M7/02
Inventor 连小珉王通彭博
Owner TSINGHUA UNIV
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