CN106382979A - Measuring device and method of laser vibration measuring instrument step response - Google Patents
Measuring device and method of laser vibration measuring instrument step response Download PDFInfo
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- CN106382979A CN106382979A CN201610849472.3A CN201610849472A CN106382979A CN 106382979 A CN106382979 A CN 106382979A CN 201610849472 A CN201610849472 A CN 201610849472A CN 106382979 A CN106382979 A CN 106382979A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
- G01H9/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
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Abstract
The present invention relates to a measuring device and method of laser vibration measuring instrument step response and belongs to the photoelectric measurement technical field. The measuring device of the present invention comprises a measured laser vibration measuring instrument, a polarizer P1, a polarizer P2, a polarizing reflector M1, a semi-transmitting and semi-reflection mirror M2, an acousto-optic modulator AOM1, an acousto-optic modulator AOM2, an FM signal source, a square wave signal source, a sinusoidal signal source, a semi-transmitting and semi-reflection mirror M3, reflectors M4, M5, M6 and M7, a semi-transmitting and semi-reflection mirror M8, a photoelectric detector and the like. Optical frequency modulation signals are down-converted into a radio frequency range through beat-frequency processing; a signal waveform sequence is obtained by means of high-speed data acquisition and quantization technologies; instantaneous frequency accurate demodulation of laser frequency modulation signal waveforms is realized through a digitization mode, so that standard motion velocity waveforms and motion acceleration waveforms can be obtained; and problems in accurate measurement and value traceability of the step response of the laser vibration measuring instrument can be solved.
Description
Technical field
The present invention relates to a kind of measurement apparatus of laser vibration measurer step response and method, belong to photoelectric measurement technology neck
Domain.
Background technology
Laser vibration measurer is a kind of general, basic vibration, shock measurement instrument, have high accuracy, noncontact, to tested
Object no additional interference and the measuring instrument of impact, its measurement and calibration is always industry difficulties, is primarily due to its
It is actuated to motion value (displacement, speed, acceleration), and measuring principle used is to be carried out by laser doppler, need
Perception physical motion is changed by light frequency, output is to provide result with electrical signal data form again, is related to mechanical movement, light
The different aspects such as frequency control, electronic surveying.
It is all generally to be encouraged by " standard vibration machine " to its measurement and calibration, value survey is carried out with " standard laser vialog "
Other laser vibration measurers are carried out measurement and calibration by amount.Because shake table belongs to the physical motion device of electromechanical structure, it is limited to thing
The restriction of reason principle and theory of mechanics etc., and the restriction of material, mechanical process capacity etc., and this photoelectric measuring of laser vibration measurer
Measuring appratus are compared, and its stability is difficult to reach very high, and frequency band is narrower, and amplitude can reach and compares larger quantities in low frequency
Value, and under high frequency situations, amplitude only enables very little value, and the degree of accuracy is relatively low, is difficult to reach and carries out to vibration measurement with laser
Measure the technical requirements traced to the source.Although carrying out measurement and calibration using standard laser vialog, because shake table characteristic causes not
Restriction caused by degree of certainty and its amplitude and frequency range remains mainly asks present in laser vibration measurer measurement and calibration
Topic.On the other hand, using standard laser vialog, metering is carried out to other laser vibration measurers and trace to the source itself, there is also in logic
Problem be that the measurement and calibration problem of standard laser vialog oneself still cannot achieve a solution.
Content of the invention
The invention aims to solving to be limited to the machinery fortune such as shake table present in laser vibration measurer measurement and calibration
Vialog range cannot be completely covered for dynamic technical parameter and stability is not so good as the subject matter of vialog, and standard laser is surveyed
Vibration Meter measures the problem that cannot be fully solved of tracing to the source, and proposes a kind of measurement apparatus of laser vibration measurer step response and measurement side
Method.
The present invention is achieved by the following technical solutions.
A kind of laser vibration measurer step response measurement apparatus, including laser vibration measurer, the first polarizer, the second polarizer,
Polarizing mirror, the first semi-transparent semi-reflecting lens, first sound-optic modulator, second sound-optic modulator, FM signal source, square-wave signal source,
Sine signal source, the second semi-transparent semi-reflecting lens, the first speculum, the second speculum, the 3rd speculum, the 4th speculum, the 3rd half
Semi-reflective mirror, photodetector, filter amplifier, digital oscilloscope and electronic computer thoroughly.
A kind of measurement apparatus of laser vibration measurer step response, concrete measuring method is：
The Frequency Stabilized Lasers being sent by laser vibration measurer, through the first polarizer, polarizing mirror, are transmitted through first semi-transparent half
It is divided into two after anti-mirror, a road, through first sound-optic modulator, is modulated by the FM signal source of square-wave frequency modulation, produce the light of+1 order of diffraction
Frequency modulation, its modulation waveform is square-wave signal, and median frequency is at the optical frequency of+1 order of diffraction of first sound-optic modulator.The
The core devices that one acousto-optic modulator is modulated as optical frequency, realize optical frequency step.This signal is another after the second semi-transparent semi-reflecting lens
It is divided into two, -1 order diffraction shift frequency through second sound-optic modulator for the road, obtaining median frequency is laser vibration measurer output frequency
Light frequency modulation, second sound-optic modulator is as optical frequency frequency displacement device.Through the first speculum, the second speculum, the 3rd reflection
After mirror, the 4th speculum reflection, laser vibration measurer is returned to optical frequency vibration performance and measures process, obtain laser vibration measurer
Step response waveform.Sine signal source therein is used for controlling -1 grade of frequency of second sound-optic modulator.An other road and first
The non-modulated optical frequency signal that semi-permeable and semi-reflecting mirror splits carries out beat frequency, obtains the frequency modulated signal of rf frequency, warp
Cross photodetector to receive, obtain the square wave FM signal in radio-frequency region, this signal gathers through digital oscilloscope, is computed
After machine is digitized demodulation, obtain frequency demodulation wave sequence：
Calculate according to formula (1) and obtain movement velocity wave sequence
In formula, the optical maser wavelength that λ exports for laser vibration measurer；Movement velocity instantaneous estimation value, (i=1,2 ..., M)；For modulation waveform frequency shift value, (i=1,2 ..., M)；M is the sequence length after demodulation.
Calculate according to formula (2) and obtain acceleration of motion wave sequence
Thus completing the assignment procedure of the measurement apparatus of laser vibration measurer.
Acceleration of motion instantaneous estimation value, (i=1,2 ..., M)；D is symbol of differentiating.T is time variable.
Laser vibration measurer movement velocity or acceleration of motion measurement result are compared with above-mentioned wave sequence parameter, permissible
Obtain the calibration result that vibration measurement with laser moves step response characteristic.
Beneficial effect
The present invention controls optical signal to produce the laser Doppler signal with galloping motion feature using electric signal, with optical frequency
Control change to replace the mechanical movement of physics to produce Doppler frequency shift mode, directly produce the optical frequency with motion Doppler feature
Modulated signal, thus avoid the difficult point that mechanical movement produces high-quality step signal.By this measurement and calibration laser vibration measurer
Step response characteristic, compared with the excitation of shock machine, the present invention has a faster rise time, broader frequency range, more greatly
Amplitude range.
The parameter assignment of the step excitation signal producing with regard to this device, is will to be become under this light frequency modulation by beat frequency
Frequency, to radio-frequency region, then, obtains signal waveform sequence by means of high-speed data acquisition and quantification technique, real with digital form
The instantaneous frequency of existing laser frequency modulated signal waveform accurately demodulates, and then obtains the vibration velocity waveform as standard and vibration
Acceleration pulse, and finally solve the problems, such as accurate measurement and the magnitude tracing of laser vibration measurer step response itself.Therefore, this
Line motor message (line movement velocity, line acceleration of motion) value is traced to the source by bright being actually by frequency modulation(PFM) and demodulation techniques
To on frequency value, thus from principle, there is the accuracy of measurement higher than mechanical movement excitation and stability.
Brief description
Fig. 1 is a kind of laser vibration measurer step response measurement apparatus structural representation of the present invention；
Wherein, P1- first polarizer, P2- second polarizer, M1- polarizing mirror, M2- first semi-transparent semi-reflecting lens,
AOM1- first sound-optic modulator, AOM2- second sound-optic modulator, M3- second semi-transparent semi-reflecting lens, M4- first speculum, M5-
Two-mirror, M6- the 3rd speculum, M7- the 4th speculum, M8- the 3rd semi-transparent semi-reflecting lens.
Specific embodiment
The present invention will be further described with reference to the accompanying drawings and examples.
As shown in figure 1, a kind of laser vibration measurer step response measurement apparatus, including laser vibration measurer, the first polarizer
(P1), the second polarizer (P2), polarizing mirror (M1), the first semi-transparent semi-reflecting lens (M2), first sound-optic modulator (AOM1),
Two acousto-optic modulators (AOM2), FM signal source, square-wave signal source, sine signal source, the second semi-transparent semi-reflecting lens (M3), the first reflection
Mirror (M4), the second speculum (M5), the 3rd speculum (M6), the 4th speculum (M7), the 3rd semi-transparent semi-reflecting lens (M8), light electrical resistivity survey
Survey device, filter amplifier, digital oscilloscope and electronic computer.
Specifically measuring method is：
The Frequency Stabilized Lasers being sent by laser vibration measurer, through the first polarizer (P1), polarizing mirror (M1), are transmitted through
It is divided into two after one semi-transparent semi-reflecting lens (M2), a road, through first sound-optic modulator (AOM1), is adjusted by the FM signal source of square-wave frequency modulation
System, produces the light frequency modulation of+1 order of diffraction, and its modulation waveform is square-wave signal, and median frequency is in first sound-optic modulator
(AOM1) at the optical frequency of+1 order of diffraction.This signal is divided into two after the first semi-transparent semi-reflecting lens (M3) again, and a road is through the rising tone
- 1 order diffraction shift frequency of optical modulator (AOM2), obtains the light frequency modulation that median frequency is laser vibration measurer output frequency,
After the first speculum M4, the second speculum M5, the 3rd speculum M6, the 4th speculum M7 reflection, returned with optical frequency vibration performance
Measure process to laser vibration measurer, obtain the step response waveform of laser vibration measurer.Sine signal source therein is used for controlling
- 1 grade of frequency of second sound-optic modulator (AOM2) processed.An other road is non-modulated with what the first semi-transparent semi-reflecting lens (M2) split
Optical frequency signal carry out beat frequency, obtain the frequency modulated signal of rf frequency, receive through photodetector, obtain radio-frequency region
Interior square wave FM signal, this signal gathers through digital oscilloscope, is digitized through computer after demodulation, obtains frequency solution
Adjust wave sequence：
Calculate according to formula (1) and obtain movement velocity wave sequence
In formula, the optical maser wavelength that λ exports for laser vibration measurer；
Calculate according to formula (2) and obtain acceleration of motion wave sequence
Thus completing the assignment procedure of the measurement apparatus of laser vibration measurer.
Laser vibration measurer movement velocity or acceleration of motion measurement result are compared with above-mentioned wave sequence parameter, permissible
Obtain the calibration result that vibration measurement with laser moves step response characteristic.
The above is presently preferred embodiments of the present invention, and the present invention should not be limited to this embodiment and accompanying drawing institute is public
The content opened.Every without departing from complete equivalent or modification under spirit disclosed in this invention, each fall within the model of present invention protection
Enclose.
Claims (2)
1. a kind of laser vibration measurer step response of the present invention measurement apparatus it is characterised in that：Including laser vibration measurer, first
Polarizer, the second polarizer, polarizing mirror, the first semi-transparent semi-reflecting lens, first sound-optic modulator, second sound-optic modulator, FM
Signal source, square-wave signal source, sine signal source, the second semi-transparent semi-reflecting lens, the first speculum, the second speculum, the 3rd speculum,
4th speculum, the 3rd semi-transparent semi-reflecting lens, photodetector, filter amplifier, digital oscilloscope and electronic computer；
Light path is moved towards：The Frequency Stabilized Lasers being sent by laser vibration measurer, through the first polarizer, polarizing mirror, are transmitted through
It is divided into two after one semi-transparent semi-reflecting lens, a road, through first sound-optic modulator, is modulated by the FM signal source of square-wave frequency modulation, produce+1 and spread out
Penetrate the light frequency modulation of level, its modulation waveform is square-wave signal, and median frequency is in+1 order of diffraction of first sound-optic modulator
At optical frequency；The core devices that first sound-optic modulator is modulated as optical frequency, realize optical frequency step；This signal is semi-transparent semi-reflecting through second
It is divided into two after mirror again, -1 order diffraction shift frequency through second sound-optic modulator for the road, obtaining median frequency is that laser vibration measurer is defeated
Go out the light frequency modulation of frequency, second sound-optic modulator is as optical frequency frequency displacement device；Through the first speculum, the second speculum,
After 3rd speculum, the 4th speculum reflection, laser vibration measurer is returned to optical frequency vibration performance and measures process, obtain laser
The step response waveform of vialog；Sine signal source therein is used for controlling -1 grade of frequency of second sound-optic modulator；Other one
The non-modulated optical frequency signal that road and the first semi-permeable and semi-reflecting mirror split carries out beat frequency, obtains the frequency modulation(PFM) of rf frequency
Signal, receives through photodetector, obtains the square wave FM signal in radio-frequency region, this signal is adopted through digital oscilloscope
Collection, is digitized through computer after demodulation, obtains frequency demodulation wave sequence.
2. as claimed in claim 1 a kind of measuring method of the measurement apparatus of laser vibration measurer step response it is characterised in that：
The frequency demodulation wave sequence that described computer obtains after being digitized demodulating：
Calculate according to formula (1) and obtain movement velocity wave sequence
In formula, the optical maser wavelength that λ exports for laser vibration measurer；Movement velocity instantaneous estimation value, (i=1,2 ..., M)；For adjusting
Waveform frequency shift value processed, (i=1,2 ..., M)；M is the sequence length after demodulation；
Calculate according to formula (2) and obtain acceleration of motion wave sequence
Thus completing the assignment procedure of the measurement apparatus of laser vibration measurer；
Wherein,Acceleration of motion instantaneous estimation value, (i=1,2 ..., M)；D is symbol of differentiating, and t is time variable；
Laser vibration measurer movement velocity or acceleration of motion measurement result are compared with above-mentioned wave sequence parameter, can obtain
Vibration measurement with laser moves the calibration result of step response characteristic.
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Cited By (5)
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| CN107560814A (en) * | 2017-09-29 | 2018-01-09 | 浙江省计量科学研究院 | The reliability test system of laser vibration measurer |
| CN107966172A (en) * | 2017-11-24 | 2018-04-27 | 电子科技大学 | A kind of wideband photodetectors responsiveness tester and its test method |
| CN109374554A (en) * | 2018-12-08 | 2019-02-22 | 山西大学 | A kind of laser frequency scanning means and method |
| CN110849465A (en) * | 2019-11-27 | 2020-02-28 | 中国航空工业集团公司北京长城计量测试技术研究所 | Arbitrary waveform optical frequency modulation and tracing device |
| CN110849466A (en) * | 2019-11-27 | 2020-02-28 | 中国航空工业集团公司北京长城计量测试技术研究所 | Optical frequency modulation device and method for arbitrary waveform |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107560814A (en) * | 2017-09-29 | 2018-01-09 | 浙江省计量科学研究院 | The reliability test system of laser vibration measurer |
| CN107966172A (en) * | 2017-11-24 | 2018-04-27 | 电子科技大学 | A kind of wideband photodetectors responsiveness tester and its test method |
| CN109374554A (en) * | 2018-12-08 | 2019-02-22 | 山西大学 | A kind of laser frequency scanning means and method |
| CN110849465A (en) * | 2019-11-27 | 2020-02-28 | 中国航空工业集团公司北京长城计量测试技术研究所 | Arbitrary waveform optical frequency modulation and tracing device |
| CN110849466A (en) * | 2019-11-27 | 2020-02-28 | 中国航空工业集团公司北京长城计量测试技术研究所 | Optical frequency modulation device and method for arbitrary waveform |
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Application publication date: 20170208 |