Speed estimation laser vibration measurement phase demodulation method
A technology of laser vibration measurement and phase demodulation, applied in measuring devices, measuring ultrasonic/sonic/infrasonic waves, instruments, etc., to achieve the effect of expanding the application range, reducing the amount of data, and reducing requirements
Active Publication Date: 2018-10-09
HARBIN INST OF TECH
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[0009] The purpose of this invention is to provide a new phase demodulation method for the problem that the traditional phase demodulation algorithm limits the measurement speed of homodyne orthogonal laser Innovate the phase demodulation method for big problems, reduce the requirements for sampling rate and memory during high-speed measurement, increase the maximum speed that the vibrometer can measure, and meet the needs of high-speed vibration measurement
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[0033] Specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.
[0034] A speed estimation laser vibrometer phase demodulation method, the method includes the following steps:
[0035] (1) For the collected original interferometric quadrature signal I x and I y Make gain and offset corrections;
[0036] (2) According to I x and I y Calculate the phase sequence as follows
[0037]
[0038] where arctan() is the arc tangent function;
[0039] (3) Phases at the initial two moments with In a stripe, the displacement d corresponding to the initial two moments is calculated according to the following formula 1 and d 2 :
[0040]
[0041]
[0042] where λ is the laser wavelength;
[0043] (4) For the subsequent moments i=3, 4, ..., estimate the velocity, displacement, phase integer term and phase fractional term at the corresponding time according to the following formula:
[0044]
[004...
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A speed estimation laser vibration measurement phase demodulation method belongs to the laser vibration measurement technology field. The phase demodulation method comprises the following steps of carrying out gain and offset correction on an original interference orthogonal signal; calculating a phase sequence; calculating an initial displacement, an estimated speed, a displacement, a phase integer term and a phase decimal item; and determining an actual phase integer item and an actual displacement according to the difference value between an actual phase decimal item and an estimated phasedecimal item, and realizing phase demodulation. In the invention, problems that a sampling frequency is too high and a data amount is too large in a traditional phase demodulation method during high-speed vibration measurement in a homodyne laser interference vibration measurement technology can be solved, a vibration measurement speed can be effectively increased, hardware cost is reduced and a laser vibration measurement instrument application range is enlarged.
Description
technical field [0001] The invention belongs to the technical field of laser vibration measurement, and mainly relates to a velocity estimation laser vibration measurement phase demodulation method. Background technique [0002] Homodyne laser vibration measurement technology has the advantages of simple structure, high measurement accuracy, wide dynamic range and easy nonlinear compensation, etc. It is widely used in displacement dynamic measurement, vibration measurement and monitoring, ultra-precision equipment and system integration, scientific research and experiments, etc. field. The homodyne laser vibrometers in the high-end and cutting-edge fields mostly adopt the four-channel homodyne orthogonal laser interferometric vibrometer scheme, using polarized light phase-shifting interference technology to obtain two orthogonal photoelectric signals, and through signal processing such as phase demodulation to realize High-precision measurement of displacement and vibration...
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Inventor 边星元何张强江文雪谭久彬崔俊宁
Owner HARBIN INST OF TECH