CN103162815A - Method for ensuring power spectrum high-and-low energy region of hydraulic machinery vibration signals - Google Patents

Method for ensuring power spectrum high-and-low energy region of hydraulic machinery vibration signals Download PDF

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CN103162815A
CN103162815A CN2012105328795A CN201210532879A CN103162815A CN 103162815 A CN103162815 A CN 103162815A CN 2012105328795 A CN2012105328795 A CN 2012105328795A CN 201210532879 A CN201210532879 A CN 201210532879A CN 103162815 A CN103162815 A CN 103162815A
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frequency
vibration signal
power spectrum
energy
piecewise function
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赵越
李正
明君
李屹
王从寅
赵明晗
赵英男
李振龙
辛艳东
郭全宝
刘智良
孙德友
童文波
覃咏麟
魏方睿
吴可君
邵国辉
徐用良
刘登峰
张金伟
赵伟
张颖
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HARBIN INSTITUTE OF LARGE ELECTRICAL MACHINERY
NATIONAL ENGINEERING RESEARCH CENTER-HYDROPOWER EQUIPMENT
Harbin Electric Machinery Co Ltd
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HARBIN INSTITUTE OF LARGE ELECTRICAL MACHINERY
NATIONAL ENGINEERING RESEARCH CENTER-HYDROPOWER EQUIPMENT
Harbin Electric Machinery Co Ltd
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Abstract

The invention relates to a method for ensuring a power spectrum high-and-low energy region of hydraulic machinery vibration signals. In a power spectrum of the hydraulic machinery vibration signals, an obvious juncture point exists between a low-frequency high energy region and a high-frequency low energy region, a variation tendency of the energy of the low-frequency high energy region and the high-frequency low energy region in the power spectrum of the hydraulic machinery vibration signals along with a vibration signal frequency is matched by adopting a piecewise function which is matched by a least squares fit, an intersection point of deviation square and the minimum piecewise function is the demarcation point of the low-frequency high energy region and the high-frequency low energy region in the power spectrum of the hydraulic machinery vibration signals.

Description

Determine the method for the high low energy area of hydraulic vibration signal power spectrum
Technical field: the method that the present invention relates to the high low energy area of a kind of definite hydraulic vibration signal power spectrum.
Background technology: further deeply reach the user to the progressively raising of hydraulic stability requirement along with what the hydraulic internal characteristic was studied, guarantee that hydraulic safe and stable operation under the non-cavitating state has become an important indicator of examination hydraulic running status.At present, utilize the regularity of energy distribution of analyzing hydraulic internal vibration signal to be used as judging that the whether research of hydraulic generation cavitation has become a kind of method that the engineering using value is arranged very much of judging that hydraulic machinery cavitation occurs.The generation that the regularity of energy distribution in the low frequency high-energy district of the vibration signal of the method when analyzing before and after hydraulic generation cavitation and high frequency low-yield district is judged cavitation phenomenon whether.Only have the low frequency high-energy district that delimit exactly vibration signal and high frequency low-yield district, the accuracy of the above-mentioned hydraulic machinery cavitation decision method of guarantee.Therefore, it is very necessary setting up a kind of method of utilizing power spectrum to distinguish hydraulic vibration signal low frequency high-energy zone and high frequency low energy area.
Summary of the invention: the present invention is when the regularity of energy distribution in the low frequency high-energy district of the vibration signal that carries out hydraulic and high frequency low-yield district, provides a kind of computer program that can adopt to determine the method for the high low energy area of hydraulic vibration signal power spectrum in hydraulic vibration signal power spectrum.Technical scheme of the present invention is:
1, start computer system;
2, the vibration signal that gathers is carried out power spectrumanalysis;
3, at the interval (x of frequency analysis 0, x n-1) in, x is arranged i=x 0+ ih, wherein: i=0,1,2 ..., n-1, and h is frequency resolution.Make x m=x i+1, set up respectively piecewise function one time
Figure DEST_PATH_GDA00003093484100021
y ‾ = k 0 x + b 0 , x ≤ x m k 1 x + b 1 , x > x m
In formula:
Figure DEST_PATH_GDA00003093484100023
Represent one time piecewise function;
x mRepresent one time piecewise function
Figure DEST_PATH_GDA00003093484100024
Intersection point;
k 0, k 1Represent one time piecewise function
Figure DEST_PATH_GDA00003093484100025
In once coefficient;
b 0, b 1Represent one time piecewise function Middle constant term;
4, make each measurement data (x of vibration signal i, y i) be V to the deviation of an above-mentioned piecewise function i, have
Figure DEST_PATH_GDA00003093484100027
That is:
V i = y i - k 0 x i - b 0 , x i ≤ x m y i - k 1 x i - b 1 , x i > x m
If x i≤ x mThe time n arranged 1Individual measurement data, x iX mThe time n arranged 2Individual measurement data, i.e. n 1+ n 2=n, the quadratic sum Q of deviation iFor:
Q i = Σ V i 2 = Σ n 1 V i 2 + Σ n 2 V i 2 = Σ i = 0 n 1 - 1 [ y i - ( k 0 x i + b 0 ) ] 2 + Σ i = n 1 n - 1 [ y i - ( k 1 x i + b 1 ) ] 2
Order ∂ Q i ∂ k 0 = 0 , ∂ Q i ∂ k 1 = 0 , ∂ Q i ∂ b 0 = 0 , ∂ Q i ∂ b 1 = 0 To determine corresponding k 0, b 0, k 1And b 1,
In formula:
Figure DEST_PATH_GDA00003093484100031
Q iTo k 0Partial derivative;
Figure DEST_PATH_GDA00003093484100032
Q iTo k 1Partial derivative;
Figure DEST_PATH_GDA00003093484100033
Q iTo b 0Partial derivative;
Figure DEST_PATH_GDA00003093484100034
Q iTo b 1Partial derivative;
Calculate respectively x m=x i+1The time Q iValue;
5, to all Q iValue sorts, sum of square of deviations Q iMinimum value Q IminCorresponding vibration signal power spectrum low frequency high-energy zone and piecewise function of high frequency low energy area
Figure DEST_PATH_GDA00003093484100035
Intersection frequency value x BBe low frequency high-energy zone and high frequency low energy area energy separation in hydraulic vibration signal power spectrum;
6, output result of calculation.
In the power spectrum of hydraulic vibration signal, the variation tendency of energy is continuous, and low frequency high-energy zone presents the trend that the rising energy value along with the vibration signal frequency falls suddenly, along with the amplitude that the rising of vibration signal frequency reduces is much smaller, exist an obvious point of interface as shown in Figure 1 between low frequency high-energy zone and high frequency low energy area at high frequency low energy area energy value.If can mark off exactly low frequency high-energy zone and high frequency low energy area in hydraulic vibration signal power spectrum, just can be regional according to the low frequency high-energy and the variation of the regularity of energy distribution of high frequency low energy area whether the cavitation of hydraulic is occured to predict.Only guaranteed low frequency high-energy zone and high frequency low energy area in hydraulic vibration signal power spectrum, be low frequency high-energy zone and high frequency low energy area point of interface, science and the accuracy of dividing just may realize whether the cavitation of hydraulic is occured effectively to study.
the hydraulic vibration signal energy that represents with the discrete point form of observing in Fig. 1 can be found with the variation tendency of signal frequency, although can feel significantly low frequency high-energy zone hydraulic vibration signal power spectrum and the existence of high frequency low energy area from sense organ, but because the energy of hydraulic vibration signal in the frequency range of studying presents very large discreteness with the discrete data point of frequency change, although can adopt the piecewise function that utilizes a time as shown in Figure 2, namely set up respectively linear function according to signal energy in the zone of the low frequency high-energy in hydraulic vibration signal power spectrum and high frequency low energy area with the variation tendency of frequency respectively, intersection point as determining that thereby the low frequency high-energy zone method with high frequency low energy area point of interface reduces human factor as far as possible on determining low frequency high-energy zone in hydraulic vibration signal power spectrum and the impact of high frequency low energy area, but the weak point that between the artificial manual division low frequency high-energy zone of above-mentioned routine and high frequency low energy area, the point of interface method exists is still very obvious:
Lack unitarity and science.At first, different people, due to the angle of its observation and analysis problem and the difference of Specialized Quality, may with the variation tendency of frequency, different sensations be arranged to signal energy in low frequency high-energy zone and high frequency low energy area, thereby construct different piecewise functions, this has just inevitably caused the difference of a piecewise function intersection point.Moreover, even same person under different times, different health and psychological condition, can not be also identical for signal energy in same one group of hydraulic vibration signal power spectrum with the piecewise function that the variation tendency of frequency constructs.
In order to verify the correctness of above-mentioned judgement, for signal in same group of hydraulic vibration signal power spectrum, we have carried out respectively following test:
Test 1: relatively the professional and technical personnel of three experience, Specialized Quality all similar adopts piecewise function of artificial manual mode structure according to signal energy in above-mentioned given same group of hydraulic vibration signal power spectrum with the variation tendency of frequency, compares the difference between a piecewise function intersection point place frequency values corresponding to three.For ease of relatively, a piecewise function intersection point place frequency values is carried out normalized, corresponding data is seen Fig. 3:
As shown in Figure 3, the professional and technical personnel of three experience, Specialized Quality all similar adopts the difference between a piecewise function intersection point place frequency values of artificial manual mode structure unexpectedly to reach 11% with the variation tendency of frequency to signal energy in same group of hydraulic vibration signal power spectrum.It is contemplated that, if the not identical personnel of background carry out aforesaid operations, this is a how large magnitude for the difference between piecewise function intersection point place frequency values.
Test 2: for the same professional and technical personnel, every 30 days, require it for signal in same group of hydraulic vibration signal power spectrum, construct a piecewise function once according to energy with the artificial manual mode of variation tendency employing of frequency.Carry out altogether 3 times.More the same professional and technical personnel different times to same group of hydraulic vibration signal power spectrum in difference between a piecewise function intersection point place frequency values setting up of signal.For ease of relatively, a piecewise function intersection point place frequency values is carried out normalized, corresponding data is seen Fig. 4:
As shown in Figure 4, for the same professional and technical personnel, different times adopts the difference between a piecewise function intersection point place frequency values of artificial manual mode structure also to reach the 3% such magnitude that cannot ignore on engineering with the variation tendency of frequency to signal energy in same group of hydraulic vibration signal power spectrum.
Can't guarantee real-time.Divide low frequency high-energy zone in hydraulic vibration signal power spectrum and the purpose of high frequency low energy area, exactly will be in time whether the cavitation of hydraulic is occured to judge.The collection of hydraulic vibration signal and the calculating of power spectrum signal utilize that computer system is instantaneous to be completed, if determine that low frequency high-energy zone and high frequency low energy area must rely on manual carrying out, not only can greatly lag behind in time the speed of computer acquisition, and for carrying out the hydraulic machinery cavitation research of analyzing and processing to mass data, its labor workload is big can't be imagined;
Can't realize intelligentized cavitation monitoring purpose.The ultimate purpose that hydraulic vibration signal power spectrum is divided low frequency high-energy zone and high frequency low energy area exactly online the automatic judgement of real-time implementation computing machine hydraulic under current working whether cavitation occurs.Obviously, artificially manual definite low frequency high-energy zone and high frequency low energy area are that the cavitation that can't realize computer intelligence judgement hydraulic occurs.
Determine the deficiency of low frequency high-energy zone and high frequency low energy area method in order to make up above-mentioned artificial craft, the present invention proposes the method for utilizing computer program to determine the high low energy area of hydraulic vibration signal power spectrum.That is, adopt a piecewise function of least square fitting
Figure DEST_PATH_GDA00003093484100061
Characterize low frequency high-energy zone in hydraulic vibration signal power spectrum and high frequency low energy area energy with the variation tendency of vibration signal frequency, the intersection point x of a piecewise function of measured value and calculated value sum of square of deviations minimum BBe low frequency high-energy zone in hydraulic vibration signal power spectrum and the frequency at high frequency low energy area energy separation place, that is to say x BThe frequency at some place is low frequency high-energy zone and the high frequency low energy area energy separation in hydraulic vibration signal power spectrum.
Determine the method for the high low energy area of hydraulic vibration signal power spectrum for checking the computer program that utilizes that the present invention proposes, namely adopt the repetition degree of frequency values corresponding to the intersection point place of a piecewise function of least square fitting, same group of hydraulic vibration signal power spectrum signal moved tens of time by technical scheme of the present invention, frequency values corresponding to the intersection point place of a piecewise function that obtains each time is all identical.For given hydraulic vibration signal, the method that proposes according to the present invention can be determined to zero error the frequency values corresponding to intersection point place of the piecewise function of constructing with the variation tendency of vibration signal frequency according to low frequency high-energy zone and high frequency low energy area energy.
Definite low frequency high-energy zone and the high frequency low energy area energy separation of the employing computer approach that adopts artificial manual method and the present invention to propose all has been plotted in Fig. 2.in Fig. 2, the hydraulic vibration signal energy that represents with the discrete point form for same group is with the test figure of signal frequency change trend, can compare adopting low frequency high-energy zone and the high frequency low energy area energy separation that employing computer approach that artificial manual method and the present invention propose is determined: the corresponding frequency values M of intersection point of the piecewise function that the corresponding frequency values N of intersection point of the piecewise function that the employing computer approach of the corresponding employing the present invention proposition that represents with solid line constructs and the artificial manual method of the corresponding employing that is represented by dotted lines construct, the low frequency high-energy zone that the employing computer approach that namely adopts artificial manual method and the present invention to propose is definite and high frequency low energy area energy separation M and N numerically differ greatly.Can know by inference, will inevitably cause respectively the inconsistent of the hydraulic vibration signal regularity of energy distribution that carries out according to this with M and N dot frequency value as hydraulic vibration signal low frequency high-energy zone and high frequency low energy area energy separation, thereby directly affect the judgement that whether hydraulic is occured cavitation phenomenon.
The present invention proposes the method for determining the high low energy area of hydraulic vibration signal power spectrum.Utilize the method for the high low energy area of definite hydraulic vibration signal power spectrum that the present invention proposes, can utilize the regularity of energy distribution of analyzing hydraulic internal vibration signal to be used as accurately judging whether hydraulic cavitation phenomenon occurs.
The present invention has proposed the method for the high low energy area of definite hydraulic vibration signal power spectrum first in the research field of judging Hydrodynamic cavitation.By the repetition test research on dissimilar hydraulic, the present invention is applicable to the regularity of energy distribution of the utilization analysis hydraulic internal vibration signal of all types hydraulic and judges in hydraulic generation cavitation whether result of study.
Description of drawings:
The power spectrum of Fig. 1 hydraulic vibration signal
Low frequency high-energy zone and high frequency low energy area energy separation that the method that Fig. 2 adopts artificial manual method and the present invention to propose is determined
Fig. 3 to be different personnel determine same group of hydraulic vibration signal power spectrum signal piecewise function intersection point place frequency values
Fig. 4 is different times, the piecewise function intersection point place frequency values that same people determines same group of hydraulic vibration signal power spectrum signal
Embodiment:
The vibration signal historical data that the present invention can utilize hydraulic to collect under a certain operating condition under off-line case, according to the low frequency high-energy in hydraulic vibration signal power spectrum zone and the high frequency low energy area energy variation tendency with the vibration signal frequency, determine low frequency high-energy zone in hydraulic vibration signal power spectrum and the frequency at high frequency low energy area energy separation place, the frequency at this some place is the regional and high frequency low energy area energy separation of low frequency high-energy in hydraulic vibration signal power spectrum.
Sea of the present invention can utilize the vibration signal field data of hydraulic under a certain operating condition in online situation, complete in real time according to the low frequency high-energy in hydraulic vibration signal power spectrum zone and the high frequency low energy area energy variation tendency with the vibration signal frequency, determine low frequency high-energy zone in hydraulic vibration signal power spectrum and the frequency at high frequency low energy area energy separation place, the frequency at this some place is the work of the regional and high frequency low energy area energy separation of low frequency high-energy in hydraulic vibration signal power spectrum.
No matter be for the historical data of off-line or online real time data, the present invention all determines the high low energy area of hydraulic vibration signal power spectrum by following program:
1, start computer system;
2, the vibration signal of corresponding site under a certain stable operating condition of hydraulic that collects is carried out power spectrumanalysis;
3, at the interval (x of frequency analysis 0, x n-1) in, x is arranged i=x 0+ ih, wherein: i=0,1,2 ..., n-1, and h is frequency resolution.Make x m=x i+1, set up respectively piecewise function one time
Figure DEST_PATH_GDA00003093484100091
y ‾ = k 0 x + b 0 , x ≤ x m k 1 x + b 1 , x > x m
In formula:
Represent one time piecewise function;
x mRepresent one time piecewise function
Figure DEST_PATH_GDA00003093484100102
Intersection point;
k 0, k 1Represent one time piecewise function
Figure DEST_PATH_GDA00003093484100103
In once coefficient;
b 0, b 1Represent one time piecewise function
Figure DEST_PATH_GDA00003093484100104
Middle constant term;
4, make each measurement data (x of vibration signal i, y i) be V to the deviation of an above-mentioned piecewise function i, have
Figure DEST_PATH_GDA00003093484100105
That is:
V i = y i - k 0 x i - b 0 , x i ≤ x m y i - k 1 x i - b 1 , x i > x m
If x i≤ x mThe time n arranged 1Individual measurement data, x iX mThe time n arranged 2Individual measurement data, i.e. n 1+ n 2=n, the quadratic sum Q of deviation iFor:
Q i = Σ V i 2 = Σ n 1 V i 2 + Σ n 2 V i 2 = Σ i = 0 n 1 - 1 [ y i - ( k 0 x i + b 0 ) ] 2 + Σ i = n 1 n - 1 [ y i - ( k 1 x i + b 1 ) ] 2
Order ∂ Q i ∂ k 0 = 0 , ∂ Q i ∂ k 1 = 0 , ∂ Q i ∂ b 0 = 0 , ∂ Q i ∂ b 1 = 0 To determine corresponding k 0, b 0, k 1And b 1,
In formula:
Figure DEST_PATH_GDA000030934841001012
Q iTo k 0Partial derivative;
Figure DEST_PATH_GDA000030934841001013
Q iTo k 1Partial derivative;
Figure DEST_PATH_GDA000030934841001014
Q iTo b 0Partial derivative;
Figure DEST_PATH_GDA000030934841001015
Q iTo b 1Partial derivative;
Calculate respectively x m=x i+1The time Q iValue;
5, to all Q iValue sorts, sum of square of deviations Q iMinimum value Q IminCorresponding vibration signal power spectrum low frequency high-energy zone and piecewise function of high frequency low energy area
Figure DEST_PATH_GDA00003093484100111
Intersection frequency value x BBe low frequency high-energy zone and high frequency low energy area energy separation in hydraulic vibration signal power spectrum;
6, output result of calculation.

Claims (1)

1. the method for the high low energy area of definite hydraulic vibration signal power spectrum is characterized in that:
1, start computer system;
2, the vibration signal that gathers is carried out power spectrumanalysis;
3, at the interval (x of frequency analysis 0, x n-1) in, x is arranged i=x 0+ ih, wherein: i=0,1,2 ..., n-1, and h is frequency resolution.Make x m=x i+1, set up respectively piecewise function one time
Figure FDA00002563996000011
y ‾ = k 0 x + b 0 , x ≤ x m k 1 x + b 1 , x > x m
In formula:
Figure FDA00002563996000013
Represent one time piecewise function;
x mRepresent one time piecewise function
Figure FDA00002563996000014
Intersection point;
k 0, k 1Represent one time piecewise function
Figure FDA00002563996000015
In once coefficient;
b 0, b 1Represent one time piecewise function
Figure FDA00002563996000016
Middle constant term;
4, make each measurement data (x of vibration signal i, y i) be V to the deviation of an above-mentioned piecewise function i, have
Figure FDA00002563996000017
That is:
V i = y i - k 0 x i - b 0 , x i ≤ x m y i - k 1 x i - b 1 , x i > x m
If x i≤ x mThe time n arranged 1Individual measurement data, x iX mThe time n arranged 2Individual measurement data, i.e. n 1+ n 2=n, the quadratic sum Q of deviation iFor:
Q i = Σ v i 2 = Σ n 1 v i 2 + Σ n 2 v i 2 = Σ i = 0 n 1 - 1 [ y i ( k 0 x i + b 0 ) ] 2 + Σ i = n 1 n - 1 [ y i ( k 1 x i + b 1 ) ] 2
Order ∂ Q i ∂ k 0 = 0 , ∂ Q i ∂ k 1 = 0 , ∂ Q i ∂ b 0 = 0 , ∂ Q i ∂ b 1 = 0 To determine corresponding k 0, b 0, k 1And b 1,
In formula:
Figure FDA00002563996000026
Q iTo k 0Partial derivative;
Figure FDA00002563996000027
Q iTo k 1Partial derivative;
Figure FDA00002563996000028
Q iTo b 0Partial derivative;
Figure FDA00002563996000029
Q iTo b 1Partial derivative;
Calculate respectively x m=x i+1The time Q iValue;
5, to all Q iValue sorts, sum of square of deviations Q iMinimum value Q IminCorresponding vibration signal power spectrum low frequency high-energy zone and piecewise function of high frequency low energy area
Figure FDA000025639960000210
Intersection frequency value x BBe low frequency high-energy zone and high frequency low energy area energy separation in hydraulic vibration signal power spectrum;
6, output result of calculation.
CN2012105328795A 2012-12-11 2012-12-11 Method for ensuring power spectrum high-and-low energy region of hydraulic machinery vibration signals Pending CN103162815A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103604607A (en) * 2013-11-22 2014-02-26 哈尔滨电机厂有限责任公司 Acoustic method for determining cavitation corrosion of rotating wheel gap of model water turbine
CN103616440A (en) * 2013-11-20 2014-03-05 哈尔滨电机厂有限责任公司 Acoustic method for determining cavitation of leak-proof ring of model water turbine runner
CN111189915A (en) * 2020-01-13 2020-05-22 明君 Real-time judgment method for cavitation occurrence of hydraulic machine

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101294845A (en) * 2008-05-05 2008-10-29 西北工业大学 Multi-frequency weak signal detecting method for early failure of rotor
CN101592548A (en) * 2009-05-15 2009-12-02 东南大学 Rotor rubbing acoustic emission signal fuzzy synthesis method of discrimination based on parameter validity
CN102043908A (en) * 2010-12-29 2011-05-04 哈尔滨电机厂有限责任公司 Method for determining gasified cavitation bubble inception of runner blades of model water turbine by utilizing computer

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101294845A (en) * 2008-05-05 2008-10-29 西北工业大学 Multi-frequency weak signal detecting method for early failure of rotor
CN101592548A (en) * 2009-05-15 2009-12-02 东南大学 Rotor rubbing acoustic emission signal fuzzy synthesis method of discrimination based on parameter validity
CN102043908A (en) * 2010-12-29 2011-05-04 哈尔滨电机厂有限责任公司 Method for determining gasified cavitation bubble inception of runner blades of model water turbine by utilizing computer

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103616440A (en) * 2013-11-20 2014-03-05 哈尔滨电机厂有限责任公司 Acoustic method for determining cavitation of leak-proof ring of model water turbine runner
CN103604607A (en) * 2013-11-22 2014-02-26 哈尔滨电机厂有限责任公司 Acoustic method for determining cavitation corrosion of rotating wheel gap of model water turbine
CN111189915A (en) * 2020-01-13 2020-05-22 明君 Real-time judgment method for cavitation occurrence of hydraulic machine
CN111189915B (en) * 2020-01-13 2022-08-19 明君 Real-time judgment method for cavitation generation of hydraulic machinery

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Application publication date: 20130619