CN114088274B - Amplitude-phase comprehensive correlation identification method for helicopter main shaft bending moment identification - Google Patents
Amplitude-phase comprehensive correlation identification method for helicopter main shaft bending moment identification Download PDFInfo
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Abstract
A method for comprehensively and correlated identification of a bending moment mark of a main shaft of a helicopter, the method comprising: measuring rotor shaft section bending moment raw data of a helicopter, and carrying out harmonic analysis on the rotor shaft section bending moment raw data to obtainAmplitude sequences and phase sequences; respectively calculating the pearson product moment correlation coefficient of the amplitude sequences of the first-order harmonic components of any two test channels and the pearson product moment correlation coefficient of the phase sequences; respectively carrying out arithmetic average calculation on the pearson moment correlation coefficient of the amplitude sequence and the pearson moment correlation coefficient of the phase sequence to obtain an arithmetic average value of the amplitude correlation coefficient and an arithmetic average value of the phase correlation coefficient; multiplying the arithmetic average value of the amplitude correlation coefficient and the arithmetic average value of the phase correlation coefficient to obtain the amplitude-phase comprehensive correlation coefficient r of the two test channels Fψ The method comprises the steps of carrying out a first treatment on the surface of the According to the amplitude-phase integrated correlation coefficient r Fψ And judging whether the bending moment identifications of the two test channels are accurate or not.
Description
Technical Field
The invention is used in the field of helicopter test data analysis, and particularly relates to a method for comprehensively and relevant identification of a amplitude-phase of a helicopter main shaft bending moment mark.
Background
With the development of modern test sensor performance, test methods and inspection techniques, required main shaft bending moment can be accurately measured, and heading force, lateral force, pitching bending moment and rolling bending moment of load on a main shaft of a helicopter rotor and the center of a hub are obtained, so that the method is used for main shaft load threshold real-time monitoring and evaluation, main shaft service life evaluation, flight safety control and the like. Meanwhile, because the measuring endpoints of the bending moment of the main shaft are very many, the phenomenon of false identification is easy to generate. If the measurement identification errors occur, the analysis of misleading result data and characteristics and the subsequent multidimensional application bring direct technical hidden danger and risk to the flight safety and the development of new machines. In the development process of helicopter technology, some measurement mark authenticity identification methods are developed and formed, and the methods are generally applied to the helicopter before a flight test is started. Once the flight test is initiated, the limitations of these methods in terms of efficiency and effectiveness present difficulties and challenges to test data verification.
Disclosure of Invention
The method for comprehensively and relatively identifying the amplitude-phase of the helicopter main shaft bending moment identification accurately discriminates the helicopter main shaft bending moment measurement identification and ensures the effectiveness and accuracy of main shaft bending moment measurement data.
The technical scheme is as follows: a method for comprehensively and correlated identification of a bending moment mark of a main shaft of a helicopter, the method comprising:
measuring rotor shaft section bending moment raw data of a helicopter, and carrying out harmonic analysis on the rotor shaft section bending moment raw data to obtain an amplitude sequence and a phase sequence;
respectively calculating the pearson product moment correlation coefficient of the amplitude sequences of the first-order harmonic components of any two test channels and the pearson product moment correlation coefficient of the phase sequences;
respectively carrying out arithmetic average calculation on the pearson moment correlation coefficient of the amplitude sequence and the pearson moment correlation coefficient of the phase sequence to obtain an arithmetic average value of the amplitude correlation coefficient and an arithmetic average value of the phase correlation coefficient;
multiplying the arithmetic average value of the amplitude correlation coefficient and the arithmetic average value of the phase correlation coefficient to obtain the amplitude-phase comprehensive correlation coefficient r of the two test channels Fψ ；
According to the amplitude-phase integrated correlation coefficient r Fψ And judging whether the bending moment identifications of the two test channels are accurate or not.
Specifically, harmonic analysis is performed on the rotor shaft section bending moment raw data to obtain an amplitude sequence and a phase sequence, including:
and carrying out n whole-period data sequences of the amplitude and the phase of the first k-order harmonic components of 4 measuring channels of the helicopter rotor head on the original rotor head section bending moment data.
Specifically, the 4 measurement channels of the helicopter rotor main shaft are two directions orthogonal to each other in two parallel sections of the helicopter rotor main shaft, namely a section in direction I N, a section in direction II P, a section in direction II N and a section in direction II P, and the corresponding 4 measurement channels are provided.
Specifically, the calculation process of the n whole-period data sequences of the amplitude and the phase of the first k-order harmonic component of 4 measurement channels of the helicopter rotor head is carried out on the rotor head section bending moment raw data is as follows:
according to the rotor rotation speed signal, intercepting sampling points N of one rotation of a rotor of a data sequence harmonic wave, a time domain measured amplitude Fj of each point and a relative azimuth angle ψj of each point j, wherein N is a quotient obtained by fc/omega, and fc is the sampling frequency of a main shaft bending moment data signal;
performing discrete Fourier transform on each sampling point N to obtain a cosine component Fic of the harmonic wave; and discrete Fourier transform of the sine to obtain a sine component Fis of the harmonic, i being the order of the harmonic component;
and according to the cosine component Fic and the sine component Fis, respectively calculating the amplitude Fi of the ith-order harmonic quantity in one rotation and the phase angle psi i of the ith-order harmonic quantity.
Specifically, the pearson product moment correlation coefficient of the amplitude sequences of the first-order harmonic components of any two test channels and the pearson product moment correlation coefficient of the phase sequences are calculated respectively, and specifically include:
constructing equidistant discrete amplitude data F of any two test channels of a spindle bi And equally spaced discrete phase data ψ of any two test channels of the spindle bi ；
The discrete amplitude data F are respectively subjected to a pearson moment correlation coefficient calculation method bi And discrete phase data ψ bi Calculating to obtain the pearson moment correlation coefficient r of the amplitude sequence of the first-order harmonic components of any two measuring channels F1bi And the pearson product moment correlation coefficient r of the phase sequence Ψ1bi 。
Specifically, the amplitude-phase complex correlation coefficient r Fψ Is a dimensionless one with amplitude ranging from [ -1,1]Between them.
Specifically, according to the amplitude-phase integrated correlation coefficient r Fψ Is larger than (1)The method is small, and judges whether the bending moment identifications of the two test channels are accurate or not, and specifically comprises the following steps:
if the amplitude-phase integrated correlation coefficient r of two test channels Fψ The method meets the following conditions: r is more than or equal to 0.81 Fψ And less than or equal to 1.0, the two test channels are test channels with different cross sections and in the same direction.
Specifically, k is equal to or greater than 4.
In summary, the method for comprehensively and correlatively identifying the amplitude-phase of the helicopter main shaft bending moment mark provided by the invention has the following advantages: the correlation of the amplitude and the phase of each order harmonic of the data of different measuring channels of the bending moment of the rotor shaft of the helicopter is utilized to simply, directly, accurately and intelligently finish the identification of the bending moment mark of the main shaft.
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Fig. 1 is a schematic diagram of an amplitude-phase comprehensive correlation identification method for a helicopter main shaft bending moment identifier.
Detailed Description
The invention provides a multi-order harmonic amplitude-phase comprehensive related main shaft bending moment identification method based on a large sample, which is applied to discrimination of authenticity of a main shaft bending moment measurement identification of a helicopter, ensures validity and accuracy of main shaft bending moment measurement data, and completes verification of the method by utilizing main shaft bending moment flight actual measurement data of a certain helicopter. The method provides a new means and a new choice for discriminating the authenticity of the main shaft bending moment measuring mark, can solve the limitations of the existing identification method and improve the identification precision of the main shaft bending moment measuring mark. The method can be popularized and applied to intelligent identification of authenticity of the identification of the helicopter blade shimmy and waving moment measuring channels with different cross sections in the direction of the wing span of the helicopter blade in the direction of the perpendicular direction bending moment of the parallel cross section of the similar rotating structural member.
The amplitude-phase comprehensive correlation identification method for the helicopter main shaft bending moment identification is applied to helicopter rotor wing main shaft bending moment measurement. As shown in FIG. 1, helicopter rotor mast bending moment measurement is performed by measuring bending moments in two directions orthogonal to each other in two parallel sections, namely, the N direction of section I-I (In measurement channel), the P direction of section I-I (In measurement channel), the N direction of section II-II (In measurement channel), and the P direction of section II-II (In measurement channel), corresponding to the 4 measurement channels. The method comprises the steps of firstly carrying out harmonic analysis on the original data of 4 measuring channels of a main shaft on the basis of data effectiveness by utilizing the original data of the section bending moment of a rotor shaft measured in the stages of helicopter scientific research test flight and shaping test flight, and obtaining n whole-period data sequences of the amplitude and the phase of the first 6-order harmonic component of each measuring channel. And secondly, carrying out pearson product moment coefficient calculation on the amplitude sequence of a certain order harmonic component of any two test channels to obtain pearson product moment correlation coefficients of the amplitudes of the certain order harmonic components of the two test channels. And thirdly, calculating an arithmetic average value of the amplitude correlation coefficients of the k-order harmonic components before the two test channels to obtain the arithmetic average value of the amplitude correlation coefficients of the two test channels. Finally, the same flow and method can calculate the arithmetic average value of the phase correlation coefficients of the two test channels, multiply the amplitude value with the arithmetic average value of the phase relation number to obtain the amplitude-phase comprehensive correlation coefficient of the two test channels, and judge whether the identifications of the two test channels are accurate according to the amplitude-phase comprehensive correlation coefficient.
The application provides a method for comprehensively and relevant identification of a amplitude-phase of a helicopter main shaft bending moment mark, which comprises the following steps:
step 10: and measuring the rotor shaft section bending moment original data of the helicopter, and carrying out harmonic analysis on the rotor shaft section bending moment original data to obtain an amplitude sequence and a phase sequence.
In practical application, the rotor shaft section bending moment raw data are rotor shaft section bending moment raw data measured in the helicopter scientific research test flight and shaping test flight stage.
Specifically, harmonic analysis is performed on the rotor shaft section bending moment raw data to obtain an amplitude sequence and a phase sequence, including: and carrying out n whole-period data sequences of the amplitude and the phase of the first k-order harmonic components of 4 measuring channels of the helicopter rotor head on the original rotor head section bending moment data.
In practical applications, k is greater than or equal to 4.
Specifically, the 4 measurement channels of the helicopter rotor main shaft are two directions orthogonal to each other in two parallel sections of the helicopter rotor main shaft, namely a section in direction I N, a section in direction II P, a section in direction II N and a section in direction II P, and the corresponding 4 measurement channels are provided.
More specifically, the calculation process of the n whole-period data sequences of the amplitude and the phase of the first k-order harmonic component of 4 measurement channels of the helicopter rotor head is carried out on the rotor head section bending moment raw data is as follows:
step 101: according to the rotor rotation speed signal, intercepting the sampling point number N of one rotation of the rotor of the data sequence harmonic wave, the time domain measured amplitude Fj of each point and the relative azimuth angle ψj of each point j, wherein N is the quotient rounding obtained for fc/omega, and fc is the sampling frequency of the main shaft bending moment data signal.
The sampling points N are equally divided distributions.
Step 102: performing discrete Fourier transform on each sampling point N to obtain a cosine component Fic of the harmonic wave; and discrete Fourier transform of the sine to obtain a sine component Fis of the harmonic, wherein i is the order of the harmonic component.
Step 103: and according to the cosine component Fic and the sine component Fis, respectively calculating the amplitude Fi of the ith-order harmonic quantity in one rotation and the phase angle psi i of the ith-order harmonic quantity.
Through the above processing, two sections of the main shaft are obtainedAmplitude F of harmonic bending moment component of n rotation periods in plane orthogonal direction bip Wherein b represents the bending moment measured in two orthogonal directions of the measuring channel, i.e. two sections, b=1, 2, 3, 4,1 represents the R direction of section i-i, 2 represents the P direction of section i-i, 3 represents the R direction of section ii-ii, 4 represents the P direction of section ii-ii, wherein section i-i is parallel to section ii-ii, the R direction is in the same section as the P direction, both orthogonal.
Where i represents the harmonic order, i=1, 2, 3, …, k. k generally does not exceed 6.p represents the spindle rotation period sequence number for the selected flight test period, p=1, 2, 3, …, n.
At the same time, different harmonic bending moment component phases psi of n rotation periods in the orthogonal direction of two sections of the main shaft are obtained bip 。
Step 20: respectively calculating the pearson product moment correlation coefficient of the amplitude sequences of the first-order harmonic components of any two test channels and the pearson product moment correlation coefficient of the phase sequences;
specifically, step 20 includes:
step 201: constructing equidistant discrete amplitude data F of any two test channels of a spindle bi And equally spaced discrete phase data ψ of any two test channels of the spindle bi ；
For example, see discrete magnitude data F of equation (5) bi Each set of data has n subsamples, with n being determined by the selected time of flight.
In the above, F bip In a set of equidistant amplitude dispersion quantities F bi1 、F bi2 、F ki3 、…、F kin 。
Step 202: the discrete amplitude data F are respectively subjected to a pearson moment correlation coefficient calculation method bi And discrete phase data ψ bi Peel of amplitude sequences of first-order harmonic components of any two measuring channels is calculatedThe square-moment correlation coefficient r F1bi And the pearson product moment correlation coefficient r of the phase sequence Ψ1bi 。
For example: using formula (6) and formula (7), carrying out correlation calculation on b=1 and two groups of amplitude discrete quantities when b=1, 2, 3 and 4 respectively to obtain each harmonic component amplitude correlation coefficient array r of each measurement channel in the selected flight time period F1bi 。
Similarly, the pearson product moment correlation coefficient of the phase sequence of the first-order harmonic components of any two measurement channels is calculated by adopting a pearson product moment correlation coefficient calculation method.
For example, an array r of phase correlation coefficients of each harmonic component of each measurement channel for a selected time of flight is calculated Ψ1bi See formula (8).
Step 30: and respectively carrying out arithmetic average calculation on the pearson moment correlation coefficient of the amplitude sequence and the pearson moment correlation coefficient of the phase sequence to obtain an arithmetic average value of the amplitude correlation coefficient and an arithmetic average value of the phase correlation coefficient.
Specifically, according to formula (9), for pearson product moment correlation coefficients of the two test channel amplitude sequences, for correlation coefficient values of each row, calculating an arithmetic average value of the pearson product moment correlation coefficients to obtain an arithmetic average value of amplitude correlation coefficients between any two test channels:
specifically, according to formula (10), for pearson product moment correlation coefficients of the two test channel phase sequences, for correlation coefficient values of each row, calculating an arithmetic average value of the pearson product moment correlation coefficients to obtain an arithmetic average value of phase correlation coefficients between any two test channels:
step 40: multiplying the arithmetic average of the amplitude correlation coefficient and the arithmetic average of the phase correlation coefficient by the formula (11) to obtain the amplitude-phase comprehensive correlation coefficient r of the two test channels Fψ ；
r Fψ ＝r Fbb m ×r ψbb m (11)
It should be noted that the amplitude-phase integrated correlation coefficient r Fψ Is a dimensionless one with amplitude ranging from [ -1,1]Between them.
Step 50: according to the amplitude-phase integrated correlation coefficient r Fψ And judging whether the bending moment identifications of the two test channels are accurate or not.
In particular, if the combined amplitude-phase correlation coefficient r of two test channels Fψ The method meets the following conditions: r is more than or equal to 0.81 Fψ And less than or equal to 1.0, the two test channels are test channels with different cross sections and in the same direction.
If the pearson coefficient root mean square value of the amplitude and phase of each order harmonic component of two test channels is less than 0.81, then the two test channels are orthogonally oriented test channels of different cross-sections. Accordingly, a main shaft bending moment measuring channel identification authenticity identification criterion is established, and is shown in table 1.
Table 1 main shaft measuring channel true and false identifying criterion
In summary, the method for comprehensively and correlatively identifying the amplitude-phase of the helicopter main shaft bending moment mark provided by the invention has the following advantages: the correlation of the amplitude and the phase of each order harmonic of the data of different measuring channels of the bending moment of the rotor shaft of the helicopter is utilized to simply, directly, accurately and intelligently finish the identification of the bending moment mark of the main shaft.
Claims (8)
1. A method for comprehensively and relatively identifying a bending moment mark of a main shaft of a helicopter, which is characterized by comprising the following steps:
measuring rotor shaft section bending moment raw data of a helicopter, and carrying out harmonic analysis on the rotor shaft section bending moment raw data to obtain an amplitude sequence and a phase sequence;
respectively calculating the pearson product moment correlation coefficient of the amplitude sequences of the first-order harmonic components of any two test channels and the pearson product moment correlation coefficient of the phase sequences;
respectively carrying out arithmetic average calculation on the pearson moment correlation coefficient of the amplitude sequence and the pearson moment correlation coefficient of the phase sequence to obtain an arithmetic average value of the amplitude correlation coefficient and an arithmetic average value of the phase correlation coefficient;
multiplying the arithmetic average value of the amplitude correlation coefficient and the arithmetic average value of the phase correlation coefficient to obtain the amplitude-phase comprehensive correlation coefficient r of the two test channels Fψ ；
According to the amplitude-phase integrated correlation coefficient r Fψ And judging whether the bending moment identifications of the two test channels are accurate or not.
2. The method of claim 1, wherein performing harmonic analysis on the rotor mast section bending moment raw data to obtain an amplitude sequence and a phase sequence comprises:
and carrying out n whole-period data sequences of the amplitude and the phase of the first k-order harmonic components of 4 measuring channels of the helicopter rotor head on the original rotor head section bending moment data.
3. The method according to claim 1, characterized in that the 4 measuring channels of the helicopter rotor mast are two directions orthogonal to each other in two parallel sections of the helicopter rotor mast, namely a section in direction of hn, a section in direction of ip, a section in direction of ii and a section in direction of ip, corresponding to the 4 measuring channels.
4. The method according to claim 2, wherein the calculation process of the n full-period data sequence of the amplitude and phase of the first k-order harmonic component of 4 measurement channels of the helicopter rotor shaft is performed on the rotor shaft section bending moment raw data as follows:
according to the rotor rotation speed signal, intercepting sampling points N of one rotation of a rotor of a data sequence harmonic wave, a time domain measured amplitude Fj of each point and a relative azimuth angle ψj of each point j, wherein N is a quotient obtained by fc/omega, and fc is the sampling frequency of a main shaft bending moment data signal;
performing discrete Fourier transform on each sampling point N to obtain a cosine component Fic of the harmonic wave; and discrete Fourier transform of the sine to obtain a sine component Fis of the harmonic, i being the order of the harmonic component;
and according to the cosine component Fic and the sine component Fis, respectively calculating the amplitude Fi of the ith-order harmonic quantity in one rotation and the phase angle psi i of the ith-order harmonic quantity.
5. The method according to claim 4, wherein the pearson product moment correlation coefficients of the amplitude sequences of the first harmonic components of any two test channels and the pearson product moment correlation coefficients of the phase sequences are calculated, respectively, specifically comprising:
constructing equidistant discrete amplitude data F of any two test channels of a spindle bi And equally spaced discrete phase data ψ of any two test channels of the spindle bi ；
The discrete amplitude data F are respectively subjected to a pearson moment correlation coefficient calculation method bi And discrete phase data ψ bi Calculating to obtain the pearson moment correlation coefficient r of the amplitude sequence of the first-order harmonic components of any two measuring channels F1bi And the pearson product moment correlation coefficient r of the phase sequence Ψ1bi 。
6. The method of claim 1, wherein the web-phase complex phaseCoefficient of closure r Fψ Is a dimensionless one with amplitude ranging from [ -1,1]Between them.
7. The method according to claim 1, wherein the correlation coefficient r is based on an amplitude-phase complex Fψ Judging whether the bending moment identifications of the two test channels are accurate or not, comprising the following steps:
if the amplitude-phase integrated correlation coefficient r of two test channels Fψ The method meets the following conditions: r is more than or equal to 0.81 Fψ And less than or equal to 1.0, the two test channels are test channels with different cross sections and in the same direction.
8. The method of claim 2, wherein k is 4 or more.
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