CN111241632A - Suspension system fault pre-diagnosis method based on random matrix theory and Euclidean distance - Google Patents
Suspension system fault pre-diagnosis method based on random matrix theory and Euclidean distance Download PDFInfo
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Abstract
The invention discloses a suspension system fault pre-diagnosis method based on a random matrix theory and Euclidean distance, which comprises the following steps: s1, constructing an initial matrix based on the random matrix theory and big data; s2, converting the initial matrix into a batch random matrix through a preset mobile window; s3, converting the batch random matrix into a non-Hermite matrix according to a random matrix theory single-loop theorem; s4, calculating a characteristic value of the non-Hermite matrix, obtaining the MSR of the non-Hermite matrix according to the characteristic value, and taking the MSR as a health state value of the suspension system; s5, when the health state value MSR of the suspension system reaches an early warning value, calculating the contribution degree of each parameter; s6, calculating the distance between the contribution degree of each parameter in the step S5 and the contribution degree of each parameter in the existing various fault data, and taking the fault with the minimum distance with the current state as the fault to be generated by the suspension system, namely the predictive fault diagnosis result. The invention realizes predictive fault diagnosis by using random matrix theory and Euclidean distance, and has simple detection and high reliability.
Description
Technical Field
The invention relates to the technical field of magnetic suspension trains, in particular to a suspension system fault pre-diagnosis method based on a random matrix theory and Euclidean distance.
Background
With the popularization of magnetic levitation trains, the safety and reliability of levitation systems are receiving more and more attention. In the running process of the magnetic suspension train, once the suspension system breaks down, the train cannot run. This is largely avoided if predictive diagnostics can be performed on the system before a failure of the levitation system occurs. Therefore, how to accurately implement the predictive fault diagnosis of the suspension system is a problem which needs to be solved urgently at present.
Disclosure of Invention
In view of the above, the invention provides a suspension system fault pre-diagnosis method based on a random matrix theory and an Euclidean distance, and the method realizes predictive fault diagnosis by using the random matrix theory and the Euclidean distance, and has the advantages of simple detection and high reliability.
On one hand, the invention provides a suspension system fault pre-diagnosis method based on a random matrix theory and Euclidean distance, which comprises the following steps:
s1, constructing an initial matrix based on the random matrix theory and big data;
s2, converting the initial matrix into a batch random matrix through a preset mobile window;
s3, converting the batch random matrix into a non-Hermite matrix according to a random matrix theory single-loop theorem;
s4, calculating a characteristic value of the non-Hermite matrix, obtaining an MSR of the characteristic value according to the characteristic value, and taking the MSR as a health state value of the suspension system;
s5, when the health state value MSR of the suspension system reaches an early warning value, calculating the contribution degree of each parameter;
s6, calculating the distance between the contribution degree of each parameter in the step S5 and the contribution degree of each parameter in the existing various fault data, and taking the fault with the minimum distance with the current state as the fault to be generated by the suspension system, namely the predictive fault diagnosis result.
As a further improvement, the initial matrix is described by the expression:
wherein A represents an initial matrix, T represents a matrix transposition, R represents the number of variables, NmRepresenting the number of samples in the mth time series,represents R line NmSet of column matrices, X1、X2、Xk、XRThe elements of the initial matrix a are respectively expressed as:
in the formula, XkOne-dimensional random matrix, x, representing the k-th variable in the m-th time seriesk1、xk2、Are respectively a one-dimensional random matrix XkOf (2) is used.
As a further improvement, the expression of the batch random matrix is:
Aj=(Yj1,Yj2,...,Yjk,...,YjR)T∈CR×d(3)
in the formula, Yj1、Yj2、Yjk、YjRRespectively, a batch random matrix AjVector of length d, d representing the width of the moving window, CR×dRepresenting a matrix set of R rows and d columns, j ∈ [1, Nm-d+1]Is a batch random matrix AjWherein:
Yjk=(yk1,yk2,...,ykd)∈C1×d(4)
in the formula, yk1、yk2、ykdIs YjkElement (2) of (C)1×dRepresenting a matrix set of l rows and d columns.
As a further improvement, the width size of the moving window is obtained by the following formula:
d=R*c (6)
wherein c represents the ratio of determinant and is obtained by the following steps:
1) setting the minimum value of c as:
wherein epsilon is a proportional factor for preventing d from being too large;
2) taking the selected time sequence as an object, and taking 0.1 as a step length from the minimum value of c to 1 by c to obtain different MSR curves;
3) comparing the obtained different MSR curves, and taking the optimal c to make the curve monotonically decrease;
4) other time series are used to determine if c is appropriate.
As a further improvement, the non-Hermite matrix in step S3 is obtained specifically by: after c is obtained, the random matrix A is applied to the batchjIs normalized to obtain a standard non-Hermite matrixThe expression of (a) is:
As a further improvement, the non-Hermite matrixThe characteristic value of (a) is obtained by the following steps:
according to the following formula, a non-Hermite matrix is obtained through calculationCharacteristic value of
In the formula (I), the compound is shown in the specification,is composed ofThe matrix of equivalent singular values of (a),is composed ofThe transpose matrix of (a) is,is composed ofThe transposed matrix of (1), wherein,the following formula is used to solve:
in the formula, U is a Harley matrix.
As a further improvement, a non-Hermite matrix is definedThe MSR of the characteristic value of (1) is MSRj,qFor reflecting the matrixThe distribution of characteristic values of (a), which is obtained by the following formula:
in the formula, MSRj,qRepresents the state of health value of the suspension system at the q-th time,is a characteristic value λOf (c) is used.
As a further improvement, MSRj,qThe method is used for early warning and judgment of the suspension system, and obtains the fault early warning occurrence time of the suspension system through the following processes:
setting a threshold value theta when MSRj,q>θ, and MSRj,q-1<And when theta is reached, the q-1 moment is the moment of the fault early warning of the suspension system.
As a further improvement, a group of historical data matrixes obtained according to the fault early warning time are defined as H, wherein H belongs to EZ×M,EZ×MThe characteristic value delta of H is diag (delta) representing a matrix set of Z rows and M columns1,...,δZ) Then, the expression of the contribution of each parameter in H is specifically as follows:
in the formula, #rIs the contribution, δ, of the r-th eigenvalue in the current staterIs the r-th eigenvalue of H, and Z is the number of H eigenvalues.
As a further improvement, #rThe method is used for suspension system predictive fault diagnosis, and obtains a suspension system predictive fault diagnosis result through the following formula:
D=minDt(13)
wherein D represents the predictive failure diagnosis result of the suspension system, DtAnd representing the distance between the contribution degree of each parameter and the contribution degree of each parameter in the existing various fault data, wherein:
in the formula, #r,f,hContribution degree of the r characteristic value of the f group in the h fault, VhThe number of sets of eigenvalues in the h-th fault.
The invention provides a suspension system fault pre-diagnosis method based on a random matrix theory and Euclidean distance, which mainly realizes early fault detection through two steps: firstly, obtaining a health state value of a suspension system through a random matrix theory; secondly, calculating the contribution degree of each parameter through principal component analysis; and thirdly, selecting the minimum distance as a result by utilizing the Euclidean distance to realize a fault pre-diagnosis result, and the method has the advantages of simple diagnosis and high reliability.
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The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
fig. 1 is a flowchart of a suspension system fault pre-diagnosis method based on a random matrix theory and euclidean distance according to an embodiment of the present invention.
Detailed Description
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.
For a better understanding of the invention, the following explanations are made in advance:
fig. 1 is a flowchart of a suspension system fault pre-diagnosis method based on a random matrix theory and euclidean distance according to an embodiment of the present invention. As shown in fig. 1, the method for predicting the suspension system fault based on the random matrix theory and the euclidean distance includes the following steps:
s1, constructing an initial matrix based on the random matrix theory and big data;
s2, converting the initial matrix into a batch random matrix through a preset mobile window;
s3, converting the batch random matrix into a non-Hermite matrix (non-Hermite matrix) according to a random matrix theory single-loop theorem;
s4, calculating a characteristic value of the non-Hermite matrix, obtaining an MSR (mean spectral radius) of the characteristic value according to the characteristic value, and taking the MSR as a health state value of the suspension system;
s5, when the health state value MSR of the suspension system reaches an early warning value, calculating the contribution degree of each parameter;
s6, calculating the distance between the contribution degree of each parameter in the step S5 and the contribution degree of each parameter in the existing various fault data, and taking the fault with the minimum distance with the current state as the fault to be generated by the suspension system, namely the predictive fault diagnosis result.
From the above discussion, it is clear that the present invention achieves early fault detection primarily in two steps: firstly, analyzing a characteristic value and an energy spectrum of a complex system through a mathematical statistical method by using a Random Matrix Theory (RMT) to obtain an internal attribute of the complex system, wherein the internal attribute can be used for analyzing a relevant state of the system to reflect an operation state of the system) to obtain a health state value of a suspension system; secondly, calculating the contribution degree of each parameter through principal component analysis; and thirdly, selecting the minimum distance as a result by utilizing the Euclidean distance to realize a fault pre-diagnosis result, and the method has the advantages of simple diagnosis and high reliability.
Specifically, the steps are realized through the following processes:
assuming that the number of variables is R, the expression of the one-dimensional random matrix of the kth variable in the mth time series is as follows:
in the formula, XkOne-dimensional random matrix, x, representing the k-th variable in the m-th time seriesk1、xk2、Are respectively a one-dimensional random matrix XkElement (b) of (A), NmRepresents the number of samples in the mth time series.
The initial matrix is described as:
wherein A denotes an initial matrix, T denotes a matrix transpose, R denotes the number of variables,represents R line NmSet of column matrices, X1、X2、Xk、XRRespectively, the elements of the initial matrix a.
Setting the width of a moving window as d, and converting the initial matrix A into a batch random matrix A through the moving window with the width of dj:
Aj=(Yj1,Yj2,...,Yjk,...,YjR)T∈CR×d(3)
In the formula, Yj1、Yj2、Yjk、YjRRespectively, a batch random matrix AjVector of medium length d, CR×dRepresenting a matrix set of R rows and d columns, j ∈ [1, Nm-d+1]Is a batch random matrix AjWherein:
Yjk=(yk1,yk2,...,ykd)∈C1×d(4)
in the formula, yk1、yk2、ykdIs YjkElement (2) of (C)1×dRepresenting a matrix set of l rows and d columns.
In fact, the larger d, the larger the amount of data, the higher the accuracy of SOH (State of Health) evaluation, but the larger the amount of calculation. Therefore, it is necessary to make a reasonable choice to ensure the accuracy and efficiency of the method. According to the random matrix theory single-ring theorem, the following can be obtained:
when the appropriate c is selected, d can also be determined from equation (6):
d=R*c (6)
although d can be determined by equation (6), c is not a fixed value, but a range. Specifically, c can be obtained by the following steps:
first, the minimum value of c is set as:
wherein epsilon is a proportional factor for preventing d from being too large;
secondly, taking the selected time sequence as an object, and taking 0.1 as a step length from the minimum value of c to 1 by c to obtain different MSR curves;
thirdly, comparing the obtained different MSR curves, and taking the best c to make the curve monotonically decrease;
finally, other time series are used to determine if c is appropriate.
Note that, after c is obtained, the random matrix A is applied to the batchjIs normalized to obtain a standard non-Hermite matrixThe expression of (a) is:
in the formula (I), the compound is shown in the specification,is composed ofThe matrix of equivalent singular values of (a),is composed ofIs a transposed matrix of (1), U is a Harley momentAnd (5) arraying.
according to the following formula, a non-Hermite matrix is obtained through calculationCharacteristic value of
In the formula (I), the compound is shown in the specification,is composed ofThe transposed matrix of (2).
Then, a non-Hermite matrix is definedThe MSR of the characteristic value of (1) is MSRj,qFor reflecting non-Hermite matrixThe distribution of characteristic values of (a), which is obtained by the following formula:
in the formula, MSRj,qRepresents the state of health value of the suspension system at the q-th time,is a characteristic valueOf (c) is used.
Up to this point, the health value of the suspension system used as an arbitrary time can be obtained by the above equation (11).
As a further preferred embodiment, the MSR of the inventionj,qThe method is used for early warning and judgment of the suspension system, and obtains the fault early warning occurrence time of the suspension system through the following processes:
setting a threshold value theta when MSRj,q>θ, and MSRj,q-1<And when theta is reached, the q-1 moment is the moment of the fault early warning of the suspension system.
Furthermore, it is worth mentioning that a set of historical data matrices obtained according to the fault pre-warning time is defined as H, wherein H ∈ EZ×M,EZ×MThe characteristic value delta of H is diag (delta) representing a matrix set of Z rows and M columns1,...,δZ) Then, the expression of the contribution of each parameter in H is specifically as follows:
in the formula, #rIs the contribution, δ, of the r-th eigenvalue in the current staterIs the r-th eigenvalue of H, and Z is the number of H eigenvalues.
As a further improvement, #rThe method is used for suspension system fault pre-diagnosis, and the suspension system fault pre-diagnosis result is obtained through the following processes:
in the formula, DtIndicating the distance, psi, between the contribution of each parameter and the contribution of each parameter in the existing fault datar,f,hContribution degree of the r characteristic value of the f group in the h fault, VhIs the number of sets of eigenvalues in the h fault, where:
taking the fault with the minimum distance from the current state as the fault to be generated by the system, namely the fault pre-diagnosis result of the suspension system:
D=minDt(13)
in the formula, D represents a suspension system predictive failure diagnosis result.
In a word, the invention realizes the predictive fault diagnosis of the suspension system by using the random matrix theory and the Euclidean distance, and has the advantages of simple detection and high reliability.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (10)
1. The suspension system fault pre-diagnosis method based on the random matrix theory and the Euclidean distance is characterized by comprising the following steps of:
s1, constructing an initial matrix based on the random matrix theory and big data;
s2, converting the initial matrix into a batch random matrix through a preset mobile window;
s3, converting the batch random matrix into a non-Hermite matrix according to a random matrix theory single-loop theorem;
s4, calculating a characteristic value of the non-Hermite matrix, obtaining an MSR of the characteristic value according to the characteristic value, and taking the MSR as a health state value of the suspension system;
s5, when the health state value MSR of the suspension system reaches an early warning value, calculating the contribution degree of each parameter;
s6, calculating the distance between the contribution degree of each parameter in the step S5 and the contribution degree of each parameter in the existing various fault data, and taking the fault with the minimum distance with the current state as the fault to be generated by the suspension system, namely the predictive fault diagnosis result.
2. The method for suspension system fault pre-diagnosis based on stochastic matrix theory and Euclidean distance according to claim 1, wherein the initial matrix is described by the following expression:
wherein A represents an initial matrix, T represents a matrix transposition, R represents the number of variables, NmRepresents the number of samples in the mth time series,represents R line NmSet of column matrices, X1、X2、Xk、XRThe elements of the initial matrix a are respectively expressed as:
3. The method for predicting the suspension system fault based on the random matrix theory and the Euclidean distance according to claim 2, wherein the expression of the batch random matrix is as follows:
Aj=(Yj1,Yj2,...,Yjk,...,YjR)T∈CR×d(3)
in the formula, Yj1、Yj2、Yjk、YjRRespectively, a batch random matrix AjVector of length d, d representing the width of the moving window, CR×dRepresenting a matrix set of R rows and d columns, j ∈ [1, Nm-d+1]Is a batch random matrix AjWherein:
Yjk=(yk1,yk2,...,ykd)∈Cl×d(4)
in the formula, yk1、yk2、ykdIs YjkElement (2) of (C)1×dRepresenting a matrix set of l rows and d columns.
4. The method for predicting the suspension system fault based on the stochastic matrix theory and the Euclidean distance according to claim 3, wherein the width of the moving window is obtained by the following formula:
d=R*c (6)
wherein c represents the ratio of determinant and is obtained by the following steps:
1) setting the minimum value of c as:
wherein epsilon is a proportional factor for preventing d from being too large;
2) taking the selected time sequence as an object, and taking 0.1 as a step length from the minimum value of c to 1 by c to obtain different MSR curves;
3) comparing the obtained different MSR curves, and taking the optimal c to make the curve monotonically decrease;
4) other time series are used to determine if c is appropriate.
5. The method for predicting the suspension system fault based on the stochastic matrix theory and the Euclidean distance according to claim 4, wherein the non-Hermite matrix in the step S3 is obtained by the following means: after c is obtained, the random matrix A is applied to the batchjIs normalized to obtain a standard non-Hermite matrix The expression of (a) is:
6. The method of claim 5, wherein the non-Hermite matrix is used for suspension system fault pre-diagnosis based on stochastic matrix theory and Euclidean distanceThe characteristic value of (a) is obtained by the following steps:
according to the following formula, a non-Hermite matrix is obtained through calculationCharacteristic value of
In the formula (I), the compound is shown in the specification,is composed ofThe matrix of equivalent singular values of (a),is composed ofThe transpose matrix of (a) is,is composed ofThe transposed matrix of (1), wherein,the following formula is used to solve:
in the formula, U is a Harley matrix.
7. The method for suspension system fault pre-diagnosis based on random matrix theory and Euclidean distance according to claim 6, characterized in that a non-Hermite matrix is definedThe MSR of the characteristic value of (1) is MSRj,qFor reflecting the matrixThe distribution of characteristic values of (a), which is obtained by the following formula:
8. The method of claim 7, wherein the MSR is a method for predicting the suspension system fault based on the stochastic matrix theory and Euclidean distancej,qThe method is used for early warning and judgment of the suspension system, and obtains the fault early warning occurrence time of the suspension system through the following processes:
setting a threshold value theta when MSRj,q>θ, and MSRj,q-1<And when theta is reached, the q-1 moment is the moment of the fault early warning of the suspension system.
9. The method for pre-diagnosing the fault of the suspension system based on the random matrix theory and the Euclidean distance as claimed in claim 8, wherein a group of historical data matrixes obtained according to the fault early warning time are defined as H, wherein H is EZ×M,EZ×MThe characteristic value delta of H is diag (delta) representing a matrix set of Z rows and M columns1,...,δZ) Then, the expression of the contribution of each parameter in H is specifically as follows:
in the formula, #rIs the contribution, δ, of the r-th eigenvalue in the current staterIs the r-th eigenvalue of H, and Z is the number of H eigenvalues.
10. The method of claim 9, wherein psi is used for the suspension system fault pre-diagnosis based on the stochastic matrix theory and Euclidean distancerThe method is used for suspension system predictive fault diagnosis, and obtains a suspension system predictive fault diagnosis result through the following formula:
D=minDt(13)
wherein D represents the predictive failure diagnosis result of the suspension system, DtAnd representing the distance between the contribution degree of each parameter and the contribution degree of each parameter in the existing various fault data, wherein:
in the formula, #r,f,hContribution degree of the r characteristic value of the f group in the h fault, VhThe number of sets of eigenvalues in the h-th fault.
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