CN100437054C - Calibration measurement method and system for single-frequency steady-state sine machinery vibrating amplitude phase characteristic - Google Patents

Abstract

The present invention relates to the field of metering measurement, more specifically a vibrational calibration measuring method and a calibration measuring system. The present invention provides an improved homodyne time interval method based on a general Michelson laser interferometer. Thus, the present invention reduces calculation amount caused by noise signals, and simplifies the judgement of a zero crossing point position. The calibration measuring system comprises a Michelson laser interferometer, a computer and a synchronous data acquisition card. The present invention is applied to calibrate the work of an acceleration sensor, and has the advantages of simple software algorithm, high efficiency, high hardware platform universality and price economy. The present invention can be generalized in metering faculties and laser absolute method vibration calibration laboratories for related industry in developing countries.

Description

A kind of calibration measurement method of single-frequency steady-state sine machinery vibrating amplitude phase characteristic

Technical field

The present invention relates to the measurement field, be specifically related to the calibration measurement method and the calibration measurement system of mechanical vibration magnitude-phase characteristics.

Background technology

In the measurement field of straight line mechanical vibration, acceleration transducer commonly used is as the standard utensil of transmission of quantity value or the work implement of in-site measurement.Acceleration transducer can be when experiencing the mechanical vibration acceleration change, the electric signal of output respective change.Under the incentive action of single-frequency steady-state sinusoidal vibration, the sensitivity amplitude of acceleration transducer is defined as under the certain vibration frequency, the unimodal value of electric weight (voltage or electric charge) of acceleration transducer output and the ratio of the unimodal value of mechanical vibration acceleration of input, unit is pC/ (m.s ^-2) or mV/ (m.s ^-2); The sensitivity phase shift of acceleration transducer is defined as under the certain vibration frequency, the initial phase of the initial phase of the electric weight (voltage or electric charge) of sensor output and the mechanical vibration acceleration of input poor, and unit is ° (degree).

In the measurement field, for guaranteed discharge primary system one or measure accurately and reliably, it is an important process that acceleration transducer is calibrated.This calibration operation comprises: in the vibration frequency range of acceleration transducer work, by the selected a series of vibration frequency point of 1/3rd octaves, the accekeration of recommending with international standard ISO 16063-11 is as the aimed acceleration of calibration, under selected frequency and specific acceleration, the unimodal value of degree of will speed up sensor electrical output and initial phase compare (be divided by or subtract each other) with the unimodal value and the initial phase of the mechanical vibration acceleration of the input that acceleration transducer bears of laser interference absolute method mensuration, finish the calibration to the acceleration transducer magnitude-phase characteristics.

The laser interference absolute method of using common Michelson laser interferometer to measure single-frequency mechanical vibration acceleration comprises two kinds: fringe count method and homodyne interval method.Metrological service of domestic provinces and cities and industry vibration calibration laboratory all adopts the fringe count method, and this method principle is simple, be widely used, but therefore energy measurement acceleration amplitude only also only can carry out the calibration of acceleration transducer sensitivity amplitude.This can not satisfy the requirement of increasing user to the calibration of acceleration transducer phase shift characteristic.

Based on common Michelson laser interferometer, Germany physical technique research institute (PTB) acceleration test chamber proposed the homodyne interval method in 1996, utilize the high-speed digitization instrument of vxi bus to carry out signals collecting, finish the frequency demodulation of laser interference signal by software, realize the measurement of acceleration amplitude and initial phase, can finish the calibration of transducer sensitivity amplitude and phase shift.

Document " W.Wabinski and V.Martens.Time interval analysis ofinterferometer signals for measuring amplitude and phase ofvibrations[A] .SPIE vol.2868:166-177; 1996. " a kind of calibration steps of acceleration transducer is disclosed, its measuring process is:

The 1st step: gather the laser interference signal, remove side-play amount;

The 2nd step: to all sampled points of per half laser interference signal period (between the adjacent peaks trough) of comprising zero crossing, use three rank fitting of a polynomials, determine the zero crossing position;

The 3rd step:, forward zero crossing time interval sequence and negative sense zero crossing time interval sequence are obtained the instantaneous velocity sequence of their correspondences by Doppler effect;

The 4th step: the velocity amplitude and the initial phase that go out forward and negative sense instantaneous velocity sequence by least square fitting;

The 5th step: velocity amplitude and initial phase to forward and negative sense instantaneous velocity sequence are averaged, and then obtain the amplitude and the initial phase of acceleration;

The 6th step: carried out least square fitting to what another passage was gathered simultaneously by the school sensor voltage signal, obtain voltage magnitude and initial phase;

The 7th step:, obtain the amplitude and the phase shift of transducer sensitivity by the amplitude of acceleration and initial phase, by the voltage magnitude of school sensor and initial phase.

The prior art part that comes with some shortcomings:

(1) because the measuring beam of common Michelson laser interferometer is identical with the reference beam frequency, dependence interferes the back intensity variations and measures, therefore, the voltage signal of this class interferometer output is easy to be subjected to the influence of random disturbance factors such as photoelectricity noise.When vibration frequency was low, comparatively significantly " burr " or " shake " often appearred in the photoelectricity modulation signal of output; Even vibration frequency raises, this phenomenon still exists, as shown in Figure 1.Because have the influence of random noise, interference signal is shaken when zero passage, appearance intersects the phenomenon of zero passage for three times repeatedly in very short time, sees Fig. 2.In this case, the position of actual zero crossing can change because of The noise.

And the prior art is not considered the influence of noise to actual signal, put undue emphasis on the hardware index of high-speed digitization instrument: sampling rate 50MSa/s, this causes the original data volume of collection excessive on the one hand, causes subsequent calculations committed memory space excessive, and program run is slow; On the other hand, the high resolving power of high sampling rate correspondence makes the influence more refinement of noise signal to actual zero crossing position, causes calculated amount to increase, and but can not improve the precision of determining actual zero crossing position.

(2) method of definite zero crossing position is in the prior art: to all sampled points in the half period, use three rank fitting of a polynomials and go out curvilinear equation, obtain the zero crossing position again.Because data volume is big, computing velocity is slow, particularly under calibrating acceleration commonly used, when frequency is low, owing to crude sampling is counted out too much, so it is consuming time very long to finish this computation process.

(3) in the document, the various waveform situations that occur when calculating the instantaneous velocity sequence, and unexposed concrete computing method, step are only generally mentioned this step, need application person oneself consideration.

Therefore, the method for the prior art is very restricted when using.

Simultaneously, when application the prior art is carried out the acceleration transducer calibration, need relevant hardware system support, signals collecting is used the above VXI two passage high-speed synchronous digitizers of sampling rate 50MSa/s, and the special-purpose cabinet and the nonshared control unit of the necessary supporting vxi bus of VXI two passage high-speed synchronous digitizers.This causes the data acquisition process sub-population price of calibration system very expensive, the special-purpose cabinet price of VXI is at several ten thousand yuan on the present home market, a VXI nonshared control unit price is also more than several ten thousand yuan, and the price of two passage high-speed synchronous digitizers reaches tens0000 yuan.

Therefore, existing calibration system price is very expensive, has seriously limited and has applied.

Summary of the invention

The technical problem to be solved in the present invention is:

In the acceleration transducer calibration process, existing homodyne interval method based on common Michelson laser interferometer, computing velocity is slow, the calculated amount that noise is brought is not simplified processing, and require to be equipped with expensive hardware system, be difficult in vibration calibration industry, generally promote the use of.At its deficiency, the present invention proposes a kind of improved homodyne interval method, can use the lower hardware system of price, reduce the calculated amount that noise signal is brought, finish calibration measurement work the single-frequency steady-state sine machinery vibrating amplitude phase characteristic of acceleration transducer; Simultaneously, propose that method a kind of and of the present invention matches, generic calibration measuring system with low cost.

Technical scheme of the present invention is:

A kind of calibration measurement method of single-frequency steady-state sine machinery vibrating amplitude phase characteristic adopts the improved homodyne interval method based on common Michelson laser interferometer, it is characterized in that may further comprise the steps:

The 1st step: determine parameter;

The vibration frequency f of selected calibration, the aimed acceleration value of calibration

Given Measuring Time T _MeasWith time interval Δ t;

Determine sampling rate R, make satisfied (1) formula:

$R>\frac{\hat{a}}{f}\×3.0181\×{10}^{6}m---\left(1\right)$

And the integral multiple relation of base when sampling rate R satisfies with the data collecting card crystal oscillator;

When measuring, the output data precision of general setting data capture card is not less than 16;

The 2nd step: carry out signal sampling;

At t ₀＜t＜t ₀+ T _MeasMeasuring Time in, with the identical time interval Δ t that sampling rate R determines, two passages of synchronous data collection card 3 carry out synchronized sampling continuously respectively to the laser interference signal of photelectric receiver 4 and be calibrated the output signal of acceleration transducer 5; The signal of extraction all is voltage magnitude discrete serieses in time domain, and above-mentioned laser interference burst, and above-mentioned output signal sequence each have N point, and each point is designated as i=1,2 ..., N, sample variance time series { t _i, i=1,2 ..., the corresponding time value of each point is a five equilibrium among the N, t _I+1=t _i+ Δ t;

The laser interference burst of photelectric receiver 4 is imported into computing machine 1 through synchronous data collection card 3, is designated as { u (t _i), i=1,2 ..., N;

The output signal sequence that is calibrated sensor 5 also is imported into computing machine 1 through synchronous data collection card 3, is designated as { u ^B(t _i), i=1,2 ..., N;

The process in this step is conventional.

The 3rd step: the laser interference burst is eliminated side-play amount;

According to (2) formula:

$u^{\′}\left(t_i\right)=u\left(t_i\right)-\frac{1}{N}\underset{i=1}{\overset{M}{\mathrm{\Σ}}}u\left(t_i\right)---\left(2\right)$

Calculate the voltage discrete series { u ' (t that eliminates side-play amount _i), i=1,2 ..., N;

The 4th step: point before the screening zero passage;

The point from i=1 to i=N-1, pointwise is judged by (3) formula:

u′(t _i)·u′(t _i+1)≤0(3)

To satisfy the t of (3) formula _iValue is put array { t before charging to zero passage successively _i ^B, i=1,2 ..., L, L point altogether;

The 5th step: remove the preceding point of pseudo-zero passage that noise causes;

Calculate sampling number N in the shortest laser interference signal period by (4) formula earlier _f:

$N_f=\frac{R\·f}{\hat{a}}\×1.9883\×{10}^{-6}m---\left(4\right)$

The point from i=1 to i=L-1 again, pointwise is judged by (5) formula:

$t_{i+1}^B-t_i^B>\left[\frac{N_f}{3}\right]\·\mathrm{\Δt}---\left(5\right)$

To satisfy the t of (5) formula _iValue is put array { t before charging to true zero passage successively _i ^C, i=1,2 ..., M, M point altogether;

The 6th step: calculate zero crossing array { t _i ^D, i=1,2 ..., M;

Be total to M point, the point from i=1 to i=M, the linear scaling interpolation calculation of (6) formula is pressed in pointwise:

$t_i^D=t_i^C+\frac{\left|u^{\′}\left(t_i^C\right)\right|}{\left|u^{\′}\left(t_i^C\right)\right|+\left|u^{\′}(t_i^C+\mathrm{\Δt})\right|}\·\mathrm{\Δt},i=\mathrm{1,2},..,M---\left(6\right)$

Ideally, when change in displacement λ/2, a forward and a negative sense zero crossing can appear in the photoelectricity interference signal.Yet in actual conditions, owing to interfere voltage signal to be subjected to the influence of voltage disturbance factors such as random noise, the phenomenon of zero passage may appear intersecting repeatedly in the short time, continuous three zero passages as shown in Figure 2.In this case, The noise must be eliminated, unique zero crossing can only be determined or keep.When considering this phenomenon of actual appearance, often the frequency of photoelectricity interference fringe is lower, the time interval of two true adjacent zero crossings is bigger, with in above-mentioned three continuous zero crossings any one as unique true zero crossing, influence for the frequency demodulation result is all little, and approaching amplitude and the initial phase that obtains for least square method, its influence is very little especially.Therefore, in case judge the phenomenon of continuous zero passage, always with first zero crossing as real zero crossing.This simplification does not influence final measuring accuracy, has but improved executing efficiency significantly.

For the judgement of true zero crossing position, three loaded down with trivial details rank fitting of a polynomials have been abandoned.Utilization meets forward and backward each sampled point of true zero crossing of (3) formula, just can be obtained the position of zero crossing more accurately by the simple proportional arithmetical operation.

The 7th step: calculate zero crossing odd number time interval array { Δ t by (7) formula respectively _k ^Very, calculate zero crossing even number time interval array { Δ t by (8) formula _k ^Idol,

(7) in the formula, $k=\mathrm{1,2},3,..,\left[\frac{M}{2}\right]-1,i=2k-1$

(8) in the formula, $k=\mathrm{1,2},3,..,\left[\frac{M}{2}\right]-1,i=2k$

The 8th step: calculate odd number instantaneous frequency and even number interval instantaneous frequency at interval respectively;

Promptly for odd number zero crossing time interval array Δ t _k ^Very, calculate corresponding to unequal interval seasonal effect in time series instantaneous frequency value array { Δ f by (9) formula _k ^Very, $k=\mathrm{1,2,3},..,\left[\frac{M}{2}\right]-1;$

Calculate the corresponding discrete time value of instantaneous frequency array { t by (10) formula simultaneously _k ^{* strange}, $k=\mathrm{1,2,3},..,\left[\frac{M}{2}\right]-1:$

(10) in the formula, $k=\mathrm{1,2,3},..,\left[\frac{M}{2}\right]-1,i=2k-1$

For even number zero crossing time interval sequence Δ t _k ^Idol, calculate corresponding to unequal interval seasonal effect in time series instantaneous frequency value array f by (11) formula _k ^Idol, $k=\mathrm{1,2,3},..,\left[\frac{M}{2}\right]-1;$

Calculate the corresponding discrete time value of instantaneous frequency array { t by (12) formula simultaneously _k ^{* even}, $k=\mathrm{1,2,3},..,\left[\frac{M}{2}\right]-1:$

(12) in the formula, $k=\mathrm{1,2,3},..,\left[\frac{M}{2}\right]-1,i=2k$

(9), in (10), (11), (12) formula, all calculate from the k=1 point $k=\left[\frac{M}{2}\right]-1$ The point;

The 9th step: calculate odd number instantaneous velocity and even number interval instantaneous velocity at interval respectively, promptly calculate odd number instantaneous velocity array v at interval by (13), (14) formula respectively _k ^{* strange}With even number interval instantaneous velocity array v _k ^{* even}:

In the formula, λ is He-Ne Lasers wavelength 0.6328 μ m, calculates from the k=1 point $k=\left[\frac{M}{2}\right]-1$ The point;

The 10th step: find out at interval instantaneous velocity waveform and the even number upset minimum point of instantaneous velocity waveform at interval of odd number respectively, earlier by the R that counts of the instantaneous velocity in (15) the formula unit of calculating vibration period _f:

$R_f=\frac{\hat{a}}{{\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="C20061005722700361.png"\; state="\{\{state\}\}">f</figure-callout>}}^2}\&times;0.3202\&times;{10}^6{m}^{-1}---\left(15\right)$

Again to be not more than R _f/ 2 integer

As the waveform burst length;

For odd number instantaneous velocity array at interval, from the k=1 point to $k=\left[\frac{M}{2}\right]-1$ Point is according to the waveform burst length

The interval, be divided into a plurality of waveforms interval, when the instantaneous velocity in last waveform interval is counted not enough waveform burst length, then ignore this waveform interval;

In above-mentioned each waveform interval, to odd number at interval the instantaneous velocity array each instantaneous velocity value pointwise relatively, find out minimum point, the sequence number k of this minimum point is designated as k ^mValue is as the waveform overturn point in this waveform interval; To all waveform intervals, find out all waveform overturn point sequences of odd number interval velocity array; Be designated as { k _j ^{M is strange};

According to waveform overturn point sequence, with the k value of each waveform overturn point between the next waveform overturn point as between a half-wave zone; Since 1 extremely The k value sequence be divided between a plurality of half-wave zones;

Equally, for even number interval instantaneous velocity array, also be divided between a plurality of half-wave zones in a manner described;

The 11st step: upset half-sine wave;

Set up the at interval positive figure instantaneous velocity array of odd number, odd number interval anti-graphics instantaneous velocity array, the at interval positive figure instantaneous velocity array of even number, even number anti-graphics instantaneous velocity array, totally 4 kinds of arrays at interval respectively;

Wherein setting up the at interval positive figure instantaneous velocity array of odd number is:

For odd number instantaneous velocity array at interval, from k=1 begin to $k=\left[\frac{M}{2}\right]-1,$

When the k value belongs between the 1st half-wave zone, between the 3rd half-wave zone and between all odd number half-wave zones the time:

When the k value belongs between the 2nd half-wave zone, between the 4th half-wave zone and between all even number half-wave zones the time:

Setting up odd number interval anti-graphics instantaneous velocity array is:

For odd number instantaneous velocity array at interval, from k=1 begin to $k=\left[\frac{M}{2}\right]-1,$

When the k value belongs between the 1st half-wave zone, between the 3rd half-wave zone and between all odd number half-wave zones the time:

When the k value belongs between the 2nd half-wave zone, between the 4th half-wave zone and between all even number half-wave zones the time:

Setting up the at interval positive figure instantaneous velocity array of even number is:

For even number instantaneous velocity array at interval, from k=1 begin to $k=\left[\frac{M}{2}\right]-1,$

When the k value belongs between the 1st half-wave zone, between the 3rd half-wave zone and between all odd number half-wave zones the time:

When the k value belongs between the 2nd half-wave zone, between the 4th half-wave zone and between all even number half-wave zones the time:

Setting up even number interval anti-graphics instantaneous velocity array is:

For even number instantaneous velocity array at interval, from k=1 begin to $k=\left[\frac{M}{2}\right]-1,$

When the k value belongs between the 1st half-wave zone, between the 3rd half-wave zone and between all odd number half-wave zones the time:

When the k value belongs between the 2nd half-wave zone, between the 4th half-wave zone and between all even number half-wave zones the time:

Because the laser interference signal of common Michelson laser interferometer output does not comprise the information of any vibrational motion, so reappear the semisinusoidal waveform that the velocity wave form that is a forward, dots among Fig. 3.In Fig. 3 and Fig. 4, represent two kinds of possible velocity wave forms with solid line.For two kinds of possible velocity wave forms, the amplitude that is calculated by least square method (sinusoidal approximatioss) equates that initial phase differs 180 °.

Represent owing to be calibrated the main value scope of the phase shift [90 °, 90 °] commonly used of acceleration transducer, so the existence of 180 ° of phase differential can not bring influence to the final calibration result that is calibrated the acceleration transducer phase place.

The 12nd step: set up system of equations;

Set up the at interval positive figure instantaneous velocity system of equations of odd number, odd number interval anti-graphics instantaneous velocity system of equations, the at interval positive figure instantaneous velocity system of equations of even number, even number anti-graphics instantaneous velocity system of equations, totally 4 kinds of system of equations at interval respectively;

For each system of equations, total Individual equation, $k=\mathrm{1,2,3},..,\left[\frac{M}{2}\right]-1$

Wherein each equation is:

$v_k^{\&prime;}=A_v\cos {\mathrm{\&omega;}}_k{t}_k^{*}-B_v\sin {\mathrm{\&omega;}}_k{t}_k^{*}+C_v---\left(20\right)$

(20) in the formula, A _v, B _v, C _vBe three unknown constants, v ' _kBy the 11st the step calculate ω _kCalculate t by (21) formula _k ^*According to odd number interval or even number difference at interval, should be t respectively mutually _k ^{* strange}Or t _k ^{* even},

${\mathrm{\&omega;}}_k=2\mathrm{\&pi;}\&CenterDot;f_k^{*}---\left(21\right)$

(21) f in the formula _k ^*,, should be f respectively mutually according to odd number interval or even number difference at interval _k ^{* strange}Or f _k ^{* even}

The 13rd step: the solving equation group,

For above-mentioned each system of equations, all be to have 3 unknown constants, comprise altogether

The inconsistent equation group of individual equation is found the solution according to the least square method under the minimum meaning of square error, can solve one group of unique A _v, B _v, C _vValue;

For 4 system of equations, can solve 4 groups of A _v, B _v, C _vValue;

Finding the solution the method for inconsistent equation group, is known mathematical method, also is the method for being recommended among the international standard ISO16063-11.

The 14th step: the amplitude of calculating vibration velocity

And initial phase The amplitude of acceleration

And phase place

For above-mentioned each group A _v, B _v, C _vThe value, (22) formula of all pressing calculate vibration velocity amplitude, calculate initial phase by (23) formula:

${\hat{v}}^{\&prime;}=\sqrt{{A_{\mathrm{<figure-callout\; id="2"\; label="v"\; filenames="C20061005722700361.png"\; state="\{\{state\}\}">v</figure-callout>}}}^2+{B_v}^2}---\left(22\right)$

For 4 that calculate

Value is got arithmetic mean as effective vibration velocity amplitude

For 4 that calculate

Value is got arithmetic mean as effective initial phase

Calculate the amplitude of actual acceleration by (24), (25) formula

And phase place

${\hat{a}}^{\&prime;}=2\mathrm{\&pi;}\&CenterDot;f\&CenterDot;{\hat{v}}^{\&prime;}---\left(24\right)$

The 15th step: the amplitude of calculating the output signal that is calibrated acceleration transducer

And initial phase

For the N that is calibrated acceleration sensor outputs signals sampled point { u ^B(t _i), i=1,2 ..., N

Can construct and comprise N equational system of linear equations (26):

u ^B(t _i)＝A _ucosωt _i-B _usinωt _i+C _u (26)

(26) in the formula, A _u, B _u, C _uBe three unknown constants, ω calculates by (27) formula:

ω＝2π·f (27)

Find the solution according to the least square method under the minimum meaning of square error, can solve one group of unique A _u, B _u, C _uValue;

By (28), (29) formula, calculate the amplitude that is calibrated acceleration sensor outputs signals

And initial phase

$\hat{u}=\sqrt{{A_{\mathrm{<figure-callout\; id="2"\; label="u"\; filenames="C20061005722700361.png"\; state="\{\{state\}\}">u</figure-callout>}}}^2+{B_u}^2}---\left(28\right)$

Measure, calculate the amplitude that is calibrated acceleration sensor outputs signals And initial phase

It is conventional known method.

The 16th step: calculate and be calibrated acceleration transducer sensitivity amplitude under given vibration frequency and the acceleration

And phase shift

Calculate by (30) formula and (31) formula:

${\hat{S}}_{a^{\&prime;}}=\frac{\hat{u}}{{\hat{a}}^{\&prime;}}---\left(30\right)$

By above-mentioned 16 steps, finish the calibration measurement process.

In above-mentioned 16 steps, the 2nd step was the conventional steps of existing known technology, from the 13rd process that went on foot for the 16th step, was the data processing method of being recommended among the international standard ISO 16063-11, can think known step.Therefore, no matter in the 2nd step process, or go on foot the 16th step process from the 13rd, any variation is arranged, its whole technical proposal can be thought and is equal to the present invention.

According to calibration measurement method of the present invention, invent a kind of calibration measurement system of single-frequency steady-state sinusoidal vibration magnitude-phase characteristics simultaneously:

Comprise: common Michelson laser interferometer 1, computing machine 2;

Also comprise data collecting card 3, electric wire connecting junction 6, described data collecting card 3 is connected on the mainboard of computing machine 2; Data collecting card 3 is synchronous data collection cards, have two simulating signal input channels at least; The photelectric receiver 4 of common Michelson laser interferometer 1 is connected on the input channel of electric wire connecting junction 6, is calibrated on another input channel that acceleration transducer 5 is connected to electric wire connecting junction 6; The data output cable of electric wire connecting junction 6 is connected on the data collecting card 3.

Described data collecting card 3 is pci bus normally.Because the data collecting card of pci bus can directly be inserted on the mainboard of common computer, low price.But do not get rid of the data collecting card that adopts PXI bus, vxi bus.Even adopt the data collecting card of PXI bus, vxi bus, in system of the present invention, use method of the present invention, its calibration measurement speed is still than prior art more than fast ten times.

The coupling scheme of described data collecting card 3 are DC coupling normally.But do not get rid of the use AC coupling, just may cause respective phase shift measurement error.

Described data collecting card 3 is two channel data capture cards normally.Because need gather the laser interference signal respectively and be calibrated the output signal of acceleration transducer, but not get rid of the more multichannel data collecting card of use, as 4 channel data capture cards.Even 4 channel data capture cards, its price are still well below the price of the VXI high-speed digitization instrument of prior art.

Described data collecting card 3 can also adopt the highest sampling rate to be not more than the data collecting card of 2MSa/s.Because under most of practical situations, the sampling rate of 2MSa/s is enough, adopts the highest sampling rate to be not more than the data collecting card of 2MSa/s, can make the price of system more cheap.Only be calibrated under vibration frequency and the specific acceleration, just need to use higher sampling rate at some.

The invention has the beneficial effects as follows:

Because the present invention is to the improvement of interval method, the preceding judgment processing steps of putting of zero passage definite, the laser interference burst of sampling rate have been increased, and then filter out the preceding point sequence of real zero passage, and eliminate the zero passage of the intersection repeatedly phenomenon that noise signal causes, reduced the computational data amount; To point before the real zero passage and thereafter consecutive point totally two sampled points use linear interpolations and determine the zero crossing position, calculated amount is little, computing method are simple and efficient is high; Increase the calculation procedure of four kinds of possibility waveforms of instantaneous velocity sequence, make measurement result more accurately and reliably;

Therefore can only use common Michelson laser interferometer and synchronous data collection card, just can in the 800Hz frequency range, realize the accurate calibration of acceleration transducer sensitivity amplitude and phase shift, the uncertainty index request that is better than relevant international standard, transducer sensitivity amplitude measurement expanded uncertainty≤0.4%, phase shift expanded uncertainty of measurement≤0.4 ° (≤500Hz) and≤1 ° (other), k=2.

Calibration measurement system price of the present invention just adopts about 1/10th of prior art system price.

When the two passage synchronous data collection cards (sampling rate 5MSa/s, resolution 200ns) that use based on pci bus, the original signal data volume that rational sampling rate is gathered is little, calculates fast, and can not reduce measuring accuracy; Two passage synchronous data collection cards of pci bus do not need corresponding special-purpose cabinet and Zero greeve controller, insert common Desktop Computer and just can work; The binary channels synchronous data collection card of pci bus and the virtual instrument framework of common computer, general, economical, the cost performance height is fit to apply;

It is simply efficient that improvement interval method of the present invention has software algorithm, and the advantage of hardware platform highly versatile, price economy has the using value of generally promoting in the laser absolute method vibration calibration laboratory of metering institute of developing country and relevant industries.

Description of drawings

Fig. 1 is: near the interference signal figure of overturn point.

Fig. 2 is: the partial enlarged drawing of a plurality of zero crossings of laser interference signal.

Fig. 3 is: a kind of semisinusoidal waveform figure of situation.

Fig. 4 is: the semisinusoidal waveform figure of another kind of situation.

Fig. 5 is: the calibration measurement system schematic.

Embodiment

Further describe the present invention below in conjunction with embodiment.Scope of the present invention is not subjected to the restriction of these embodiment, and scope of the present invention proposes in claims.

A kind of calibration measurement method of single-frequency steady-state sine machinery vibrating amplitude phase characteristic, international standard ISO 16063-11 recommend first with reference to vibration frequency point 160Hz and calibration target acceleration 100m/s ², be B﹠amp to model; The acceleration transducer of K8305 (containing supporting charge amplifier) is calibrated.Measuring Time is 100ms; The time interval is 500ns.It is DC coupling that the sampling rate of data collecting card is set at the 2Msa/s coupling scheme.

According to described 16 steps, calculate the sensitivity amplitude that is calibrated acceleration transducer

Be 12.543mV/ (m.s ^-2); Phase shift

It is 0.25 °.

The sensitivity amplitude that is calibrated acceleration transducer that is obtained by traditional fringe count method is 12.552mV/ (m.s ^-2).The relative deviation of the acceleration transducer sensitivity amplitude of two kinds of method measurements is about 0.07%.

A kind of calibration measurement system of single-frequency steady-state sine machinery vibrating amplitude phase characteristic,

Comprise: common Michelson laser interferometer 1, model: GDZ-2 type; Computing machine 2, model: common Dell Pentium IV Desktop Computer;

Also comprise data collecting card 3, electric wire connecting junction 6, described data collecting card 3 is connected on the mainboard of computing machine 2; Data collecting card 3 is that synchronous data collection card, the coupling scheme of pci bus are DC coupling, have two simulating signal input channels, the highest sampling rates to be not more than 2MSa/s; The photoelectric output signal of common Michelson laser interferometer 1 is connected on the input channel of electric wire connecting junction 6, and the output signal that is calibrated acceleration transducer is connected on another input channel of electric wire connecting junction 6; The data output cable of electric wire connecting junction 6 is connected on the data collecting card 3.

In above-mentioned present embodiment calibration measurement system, use above-mentioned calibration measurement method, carried out continuous calibration measurement altogether 10 times; The actual computation time of present embodiment is about: 15 seconds.

Claims (1)

1. The calibration measurement method of 1 one kinds of single-frequency steady-state sine machinery vibrating amplitude phase characteristics adopts the improved homodyne interval method based on common Michelson laser interferometer, it is characterized in that may further comprise the steps:

   The 1st step: determine parameter;

   The vibration frequency f of selected calibration, the aimed acceleration value of calibration

   

   Given Measuring Time T _MeasWith time interval Δ t;

   Determine sampling rate R, make satisfied (1) formula:

   $R>\frac{\hat{a}}{f}\&times;3.0181\&times;{10}^{6}m---\left(1\right)$

   And the integral multiple relation of base when sampling rate R satisfies with the data collecting card crystal oscillator;

   The 2nd step: carry out signal sampling;

   At t ₀＜t＜t ₀+ T _MeasMeasuring Time in, with the definite identical time interval Δ t of sampling rate R, two passages of synchronous data collection card (3) carry out synchronized sampling continuously respectively to the laser interference signal of photelectric receiver (4) and be calibrated the output signal of acceleration transducer (5); The signal of extraction all is voltage magnitude discrete serieses in time domain, and above-mentioned laser interference burst, and above-mentioned output signal sequence each have N point, and each point is designated as i=1,2 ..., N, sample variance time series { t _i, i=1,2 ..., the corresponding time value of each point is a five equilibrium among the N, t _I+1=t _i+ Δ t;

   The laser interference burst of photelectric receiver (4) is imported into computing machine (1) through synchronous data collection card (3), is designated as { u (t _i), i=1,2 ..., N;

   The output signal sequence that is calibrated sensor (5) also is imported into computing machine (1) through synchronous data collection card (3), is designated as { u ^B(t _i), i=1,2 ..., N;

   The 3rd step: the laser interference burst is eliminated side-play amount;

   According to (2) formula:

   $u^{\&prime;}\left(t_i\right)=u\left(t_i\right)-\frac{1}{N}\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}u\left(t_i\right)---\left(2\right)$

   Calculate the voltage discrete series { u ' (t that eliminates side-play amount _i), i=1,2 ..., N;

   The 4th step: point before the screening zero passage;

   The point from i=1 to i=N-1, pointwise is judged by (3) formula:

   u′(t _i)·u′(t _i+1)≤0 (3)

   To satisfy the t of (3) formula _iValue is put array { t before charging to zero passage successively _i ^B, i=1,2 ..., L, L point altogether;

   The 5th step: remove the preceding point of pseudo-zero passage that noise causes;

   Calculate sampling number N in the shortest laser interference signal period by (4) formula earlier _f:

   $N_f=\frac{R\&CenterDot;f}{\hat{a}}\&times;1.9883\&times;{10}^{-6}m---\left(4\right)$

   The point from i=1 to i=L-1 again, pointwise is judged by (5) formula:

   $t_{i+1}^B-t_i^B>\left[\frac{N_f}{3}\right]\&CenterDot;\mathrm{\&Delta;t}---\left(5\right)$

   To satisfy the t of (5) formula _iValue is put array { t before charging to true zero passage successively _i ^C, i=1,2 ..., M, M point altogether;

   The 6th step: calculate zero crossing array { t _i ^D, i=1,2 ..., M;

   Be total to M point, the point from i=1 to i=M, the linear scaling interpolation calculation of (6) formula is pressed in pointwise:

   $t_i^D=t_i^C+\frac{\left|u^{\&prime;}\left(t_i^C\right)\right|}{\left|u^{\&prime;}\left(t_i^C\right)\right|+\left|u^{\&prime;}(t_i^C+\mathrm{\&Delta;t})\right|}\&CenterDot;\mathrm{\&Delta;t},i=\mathrm{1,2},...,M---\left(6\right)$

   The 7th step: calculate zero crossing odd number time interval array { Δ t by (7) formula respectively _k ^Very, calculate zero crossing even number time interval array { among the Δ t by (8) formula _k ^Idol,

   

   (7) in the formula, $k=\mathrm{1,2,3},...,\left[\frac{M}{2}\right]-1,i=2k-1$

   

   (8) in the formula, $k=\mathrm{1,2,3},...,\left[\frac{M}{2}\right]-1,i=2k$

   The 8th step: calculate odd number instantaneous frequency and even number interval instantaneous frequency at interval respectively;

   Promptly for odd number zero crossing time interval array Δ t _k ^Very, calculate corresponding to unequal interval seasonal effect in time series instantaneous frequency value array by (9) formula

   

   

   Calculate the corresponding discrete time value of instantaneous frequency array by (10) formula simultaneously

   

   

   (10) in the formula, $k=\mathrm{1,2,3},...,\left[\frac{M}{2}\right]-1,i=2k-1$

   For even number zero crossing time interval sequence Δ t _k ^Idol, calculate corresponding to unequal interval seasonal effect in time series instantaneous frequency value array by (11) formula

   

   

   Calculate the corresponding discrete time value of instantaneous frequency array by (12) formula simultaneously

   

   

   (12) in the formula, $k=\mathrm{1,2,3},...,\left[\frac{M}{2}\right]-1,i=2k$

   (9), in (10), (11), (12) formula, all calculate from the k=1 point $k=\left[\frac{M}{2}\right]-1$ The point;

   The 9th step: calculate odd number instantaneous velocity and even number interval instantaneous velocity at interval respectively, promptly calculate odd number instantaneous velocity array v at interval by (13), (14) formula respectively _k ^{* strange}With even number interval instantaneous velocity array v _k ^{* even}:

   

   

   In the formula, λ is He-Ne Lasers wavelength 0.6328 μ m, calculates from the k=1 point $k=\left[\frac{M}{2}\right]-1$ The point;

   The 10th step: find out at interval instantaneous velocity waveform and the even number upset minimum point of instantaneous velocity waveform at interval of odd number respectively, earlier by the R that counts of the instantaneous velocity in (15) the formula unit of calculating vibration period _f:

   $R_f=\frac{\hat{a}}{f^2}\&times;0.3202\&times;{10}^6{m}^{-1}---\left(15\right)$

   Again to be not more than R _f/ 2 integer

   

   As the waveform burst length;

   For odd number instantaneous velocity array at interval, from the k=1 point to $k=\left[\frac{M}{2}\right]-1$ Point is according to the waveform burst length

   

   The interval, be divided into a plurality of waveforms interval, when the instantaneous velocity in last waveform interval is counted not enough waveform burst length, then ignore this waveform interval;

   In above-mentioned each waveform interval, to odd number at interval the instantaneous velocity array each instantaneous velocity value pointwise relatively, find out minimum point, the sequence number k of this minimum point is designated as k ^mValue is as the waveform overturn point in this waveform interval; To all waveform intervals, find out all waveform overturn point sequences of odd number interval velocity array; Be designated as { k _j ^{M is strange};

   According to waveform overturn point sequence, with the k value of each waveform overturn point between the next waveform overturn point as between a half-wave zone; Since 1 extremely The k value sequence be divided between a plurality of half-wave zones;

   Equally, for even number interval instantaneous velocity array, also be divided between a plurality of half-wave zones in a manner described;

   The 11st step: upset half-sine wave;

   Set up the at interval positive figure instantaneous velocity array of odd number, odd number interval anti-graphics instantaneous velocity array, the at interval positive figure instantaneous velocity array of even number, even number anti-graphics instantaneous velocity array, totally 4 kinds of arrays at interval respectively;

   Wherein setting up the at interval positive figure instantaneous velocity array of odd number is:

   For odd number instantaneous velocity array at interval, from k=1 begin to $k=\left[\frac{M}{2}\right]-1,$

   When the k value belongs between the 1st half-wave zone, between the 3rd half-wave zone and between all odd number half-wave zones the time:

   

   When the k value belongs between the 2nd half-wave zone, between the 4th half-wave zone and between all even number half-wave zones the time:

   

   Setting up odd number interval anti-graphics instantaneous velocity array is:

   For odd number instantaneous velocity array at interval, from k=1 begin to $k=\left[\frac{M}{2}\right]-1,$

   When the k value belongs between the 1st half-wave zone, between the 3rd half-wave zone and between all odd number half-wave zones the time:

   

   When the k value belongs between the 2nd half-wave zone, between the 4th half-wave zone and between all even number half-wave zones the time:

   

   Setting up the at interval positive figure instantaneous velocity array of even number is:

   For even number instantaneous velocity array at interval, from k=1 begin to $k=\left[\frac{M}{2}\right]-1,$

   When the k value belongs between the 1st half-wave zone, between the 3rd half-wave zone and between all odd number half-wave zones the time:

   When the k value belongs between the 2nd half-wave zone, between the 4th half-wave zone and between all even number half-wave zones the time:

   Setting up even number interval anti-graphics instantaneous velocity array is:

   For even number instantaneous velocity array at interval, from k=1 begin to $k=\left[\frac{M}{2}\right]-1,$

   When the k value belongs between the 1st half-wave zone, between the 3rd half-wave zone and between all odd number half-wave zones the time:

   

   When the k value belongs between the 2nd half-wave zone, between the 4th half-wave zone and between all even number half-wave zones the time:

   

   The 12nd step: set up system of equations;

   Set up the at interval positive figure instantaneous velocity system of equations of odd number, odd number interval anti-graphics instantaneous velocity system of equations, the at interval positive figure instantaneous velocity system of equations of even number, even number anti-graphics instantaneous velocity system of equations, totally 4 kinds of system of equations at interval respectively;

   For each system of equations, total Individual equation,

   $k=\mathrm{1,2,3},...,\left[\frac{M}{2}\right]-1$

   Wherein each equation is:

   $v_k^{\&prime;}=A_v\cos {\mathrm{\&omega;}}_k{t}_k^{*}-B_v\sin {\mathrm{\&omega;}}_k{t}_k^{*}+C_v---\left(20\right)$

   (20) in the formula, A _v, B _v, C _vBe three unknown constants, v ' _kBy the 11st the step calculate ω _kCalculate t by (21) formula _k ^*According to odd number interval or even number difference at interval, should be t respectively mutually _k ^{* strange}Or t _k ^{* even},

   ${\mathrm{\&omega;}}_k=2\mathrm{\&pi;}\&CenterDot;f_k^{*}---\left(21\right)$

   (21) f in the formula _k ^*,, should be f respectively mutually according to odd number interval or even number difference at interval _k ^{* strange}Or f _k ^{* even}

   The 13rd step: the solving equation group,

   For above-mentioned each system of equations, all be to have 3 unknown constants, comprise altogether

   

   The inconsistent equation group of individual equation is found the solution according to the least square method under the minimum meaning of square error, can solve one group of unique A _v, B _v, C _vValue;

   For 4 system of equations, can solve 4 groups of A _v, B _v, C _vValue;

   The 14th step: the amplitude of calculating vibration velocity And initial phase

   

   The amplitude of acceleration

   

   And phase place

   For above-mentioned each group A _v, B _v, C _vThe value, (22) formula of all pressing calculate vibration velocity amplitude, calculate initial phase by (23) formula:

   ${\hat{v}}^{\&prime;}=\sqrt{{A_v}^2+{B_v}^2}---\left(22\right)$

   For 4 that calculate

   

   Value is got arithmetic mean as effective vibration velocity amplitude

   

   For 4 that calculate

   

   Value is got arithmetic mean as effective initial phase

   

   Calculate the amplitude of actual acceleration by (24), (25) formula

   

   And phase place

   

   ${\hat{a}}^{\&prime;}=2\mathrm{\&pi;}\&CenterDot;f{\&CenterDot;\hat{v}}^{\&prime;}---\left(24\right)$

   The 15th step: the amplitude of calculating the output signal that is calibrated acceleration transducer

   

   And initial phase

   

   For the N that is calibrated acceleration sensor outputs signals sampled point { u ^B(t _i), i=1,2 ..., N,

   Can construct and comprise N equational system of linear equations (26):

   u ^B(t _i)＝A _u?cosωt _i-B _u?sinωt _i+C _u (26)

   (26) in the formula, A _u, B _u, C _uBe three unknown constants, ω calculates by (27) formula:

   ω＝2π·f (27)

   Find the solution according to the least square method under the minimum meaning of square error, can solve one group of unique A _u, B _u, C _{The u value}

   By (28), (29) formula, calculate the amplitude that is calibrated acceleration sensor outputs signals

   

   And initial phase

   $\hat{u}=\sqrt{{A_u}^2+{B_u}^2}---\left(28\right)$

   

   The 16th step: calculate and be calibrated acceleration transducer sensitivity amplitude under given vibration frequency and the acceleration

   

   And phase shift Calculate by (30) formula and (31) formula:

   ${\hat{S}}_{a^{\&prime;}}=\frac{\hat{u}}{{\hat{a}}^{\&prime;}}---\left(30\right)$

   

   By above-mentioned 16 steps, finish the calibration measurement process.

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