CN110569608B

CN110569608B - Method and device for determining vibration severity of vehicle-mounted platform

Info

Publication number: CN110569608B
Application number: CN201910861179.2A
Authority: CN
Inventors: 朱玉琴; 谭勇; 杨万均; 翟庆庆; 滕俊鹏; 李迪凡; 王和平
Original assignee: No 59 Research Institute of China Ordnance Industry
Current assignee: No 59 Research Institute of China Ordnance Industry
Priority date: 2019-09-09
Filing date: 2019-09-09
Publication date: 2023-05-26
Anticipated expiration: 2039-09-09
Also published as: CN110569608A

Abstract

The application discloses a method and a device for determining vibration severity level of a vehicle-mounted platform, wherein the method comprises the following steps: the method comprises the steps of obtaining vibration acceleration signals acquired by a vibration acceleration sensor at a preset acquisition position on the vehicle-mounted platform, wherein the preset sampling position can be a vibration excitation point affecting the structure of the vehicle-mounted platform or affecting the stability or the precision of equipment on the vehicle-mounted platform or an equipment installation position point. Determining a vibration acceleration mean square value of the vibration acceleration signal and a value of a preset index, wherein the vibration acceleration mean square value represents the total power of the vibration acceleration signal, the value of the preset index represents the flatness degree of the power spectral density of the vibration acceleration signal, and the vibration severity level of the preset acquisition position of the vehicle-mounted platform is determined according to the vibration acceleration mean square value, the value of the preset index and the preset corresponding relation. According to the method, the vibration severity level of the vehicle-mounted platform is determined through the mean square value of the vibration acceleration signal and the value of the preset index.

Description

Method and device for determining vibration severity of vehicle-mounted platform

Technical Field

The present disclosure relates to the field of signal processing, and in particular, to a method and an apparatus for determining a vibration severity level of a vehicle-mounted platform.

Background

In-vehicle platforms (e.g., including vehicles and vehicle-mounted electronic devices), vibration may occur during transportation or task execution. The electronic equipment which needs to be installed at certain positions on the vehicle-mounted platform has higher sensitivity to the vibration degree of the vehicle-mounted platform, for example, the electronic equipment is relatively precise, the vibration easily causes the precision of the electronic equipment to be reduced, even the electronic equipment is damaged, the service life of the electronic equipment is shortened, and meanwhile, the reliability of the vehicle-mounted platform is also influenced.

In order to avoid the influence of vibration on the electronic equipment, it is necessary to comprehensively consider the vibration intensity at the position for mounting the electronic equipment in the vehicle-mounted platform when the electronic equipment mounted on the vehicle-mounted platform is mounted or engineering design is performed, and therefore, a method for analyzing the vibration condition of the vehicle-mounted platform is needed.

Disclosure of Invention

The application provides a method and a device for determining vibration severity level of a vehicle-mounted platform, and aims to provide a scheme capable of analyzing vibration conditions of the vehicle-mounted platform.

In order to achieve the above object, the present application provides the following technical solutions:

the application provides a method for determining vibration severity level of an on-board platform, which comprises the following steps:

Acquiring a vibration acceleration signal; the vibration acceleration signal is obtained by sampling a vibration acceleration sensor arranged at a preset acquisition position on the vehicle-mounted platform according to a preset sampling frequency;

determining the mean square value of the vibration acceleration and the value of a preset index; the mean square value of the vibration acceleration represents the total power of the vibration acceleration signal; the magnitude of the value of the preset index represents the flatness degree of the power spectral density of the vibration acceleration signal;

determining the vibration severity level of a preset acquisition position of the vehicle-mounted platform according to the vibration acceleration mean square value, the value of the preset index and the preset corresponding relation; the preset corresponding relation is a preset corresponding relation among a preset vibration acceleration mean square value, a preset index value and a preset vibration severity grade.

Optionally, the vibration acceleration signal is a triaxial vibration acceleration signal; the preset index is a variation coefficient of the normalized power spectrum component; the normalized power spectrum component refers to the distribution of power at different frequency levels;

determining the mean square value of the vibration acceleration of the triaxial vibration acceleration signal and the value of a preset index comprises the following steps:

Respectively calculating the square sum of the data in each axial vibration acceleration signal to obtain the mean square value of each axial vibration acceleration;

taking the sum of the mean square values of the vibration acceleration of each axial direction as the mean square value of the vibration acceleration;

respectively determining the power spectral density of each axial vibration acceleration signal to obtain the power spectral density of each axial direction;

taking the sum of the powers at the same frequency in the power spectrum density of each axial direction as the power at the frequency to obtain a first comprehensive power spectrum density;

calculating the variance of the normalized power spectrum component as a first variance according to the first comprehensive power spectrum density and the mean square value of the vibration acceleration;

and taking the ratio of the arithmetic square root of the first variance to the mean square value of the vibration acceleration as the value of the variation coefficient.

taking the power maximum value at the same frequency in the power spectral density of each axial direction as the power at the frequency to obtain a second comprehensive power spectral density;

calculating a mean square value of vibration acceleration under the second comprehensive power spectrum density according to the relation between the power spectrum density and the total power;

calculating the variance of the normalized power spectrum component as a second variance according to the second comprehensive power spectrum density and the mean square value of the vibration acceleration;

and taking the ratio of the arithmetic square root of the second variance to the mean square value of the vibration acceleration as the variation coefficient of the normalized power spectrum component.

respectively segmenting each axial vibration acceleration signal according to the starting time and the ending time of each speed condition in the information of the preset speed condition set to obtain a vibration acceleration signal segment set in each axial direction;

Respectively determining the power spectral density of each vibration acceleration signal segment in each axial vibration acceleration signal segment set to obtain each axial power spectral density set;

calculating the comprehensive power spectral density of each axial vibration acceleration signal section under the time length corresponding to each speed condition respectively to obtain the third comprehensive power spectral density of the triaxial vibration acceleration signal;

calculating a vibration acceleration mean square value under the third comprehensive power spectrum density as the vibration acceleration mean square value according to the relation between the power spectrum density and the total power;

calculating the variance of the normalized power spectrum component as a third variance according to the third comprehensive power spectrum density and the vibration acceleration mean square value;

and taking the ratio of the arithmetic square root of the third variance to the mean square value of the vibration acceleration as the variation coefficient of the normalized power spectrum component.

Optionally, the calculating the integrated power spectral density of the power spectral density of each axial vibration acceleration section under the time length corresponding to each speed condition respectively, to obtain the integrated power spectral density of the triaxial vibration acceleration signal as a third integrated power spectral density includes:

Respectively carrying out weighted summation on the power spectral density of each axial vibration acceleration signal section according to the time length occupation ratio corresponding to each speed condition to obtain the comprehensive power spectral density of each axial direction; the power spectral density weight of any vibration acceleration signal section in any axial direction is as follows: the duration of the speed condition which is the same as the starting time and the ending time of the vibration acceleration signal section is the same as the duration of the speed condition;

and taking the sum of the powers at the same frequency in the axial integrated power spectral density as the power at the frequency, or taking the maximum power at the same frequency in the axial integrated power spectral density as the power at the frequency, so as to obtain the integrated power spectral density of the triaxial vibration acceleration signal as the third integrated power spectral density.

Optionally, the calculating the integrated power spectrum density of each power spectrum density in each axial power spectrum density set under the duration ratio corresponding to each speed condition to obtain the integrated power spectrum density of the triaxial vibration acceleration signal as a third integrated power spectrum density includes:

taking the sum of powers at the same frequency or the maximum power at the same frequency in the power spectral densities of the vibration acceleration signal segments in the axial directions, which are the same as the starting time and the ending time of the speed condition, as the power at the frequency to obtain the comprehensive power spectral densities of the vibration acceleration signals in the three axial directions under the speed condition respectively;

Respectively carrying out weighted summation on the comprehensive power spectrum densities of the triaxial vibration acceleration signals under each speed condition to obtain the third comprehensive power spectrum density; the weight of the comprehensive power spectrum density of the triaxial vibration acceleration signal under any speed condition is as follows: the duration of the speed condition is a ratio.

The application also provides a vehicle-mounted platform vibration severity level's determining means, include:

the acquisition module is used for acquiring the vibration acceleration signal; the vibration acceleration signal is obtained by sampling a vibration acceleration sensor arranged at a preset acquisition position on the vehicle-mounted platform according to a preset sampling frequency;

the first determining module is used for determining the mean square value of the vibration acceleration and the value of a preset index; the mean square value of the vibration acceleration represents the total power of the vibration acceleration signal; the magnitude of the value of the preset index represents the flatness degree of the power spectral density of the vibration acceleration signal;

the second determining module is used for determining the vibration severity level of the preset acquisition position of the vehicle-mounted platform according to the vibration acceleration mean square value, the preset index value and the preset corresponding relation; the preset corresponding relation is a preset corresponding relation among a preset vibration acceleration mean square value, a preset index value and a preset vibration severity grade.

the first determining module is configured to determine a mean square value of vibration acceleration and a value of a preset index, and includes:

the first determining module is specifically configured to calculate a sum of squares of each data in each axial vibration acceleration signal, so as to obtain a mean square value of each axial vibration acceleration;

the first determining module is specifically configured to determine a power spectral density of each axial vibration acceleration signal, so as to obtain a power spectral density of each axial direction;

the first determining module is specifically configured to segment each axial vibration acceleration signal according to a start time and a stop time of each speed condition in information of a preset speed condition set, so as to obtain a vibration acceleration signal segment set in each axial direction;

Optionally, the first determining module is configured to calculate a comprehensive power spectral density of the power spectral density of each axial vibration acceleration section under a time length corresponding to each speed condition, and obtain a comprehensive power spectral density of the triaxial vibration acceleration signal as a third comprehensive power spectral density, where the method includes:

the first determining module is specifically configured to respectively perform weighted summation on the power spectrum density of each axial vibration acceleration signal segment according to the duration duty ratio corresponding to each speed condition, so as to obtain the comprehensive power spectrum density of each axial direction; the power spectral density weight of any vibration acceleration signal section in any axial direction is as follows: the duration of the speed condition which is the same as the starting time and the ending time of the vibration acceleration signal section is the same as the duration of the speed condition;

the first determining module is specifically configured to obtain, from power spectral densities of vibration acceleration signal segments in each axial direction, which are the same as a start time and a stop time of a speed condition, a sum of powers at the same frequency or a maximum power at the same frequency as the power at the frequency, so as to obtain comprehensive power spectral densities of the vibration acceleration signals in each axial direction under each speed condition;

In the method and the device for determining the vibration severity level of the vehicle-mounted platform, vibration acceleration signals are obtained, wherein the vibration acceleration signals are obtained by sampling a vibration acceleration sensor arranged at a preset collecting position on the vehicle-mounted platform according to a preset sampling frequency, and the mean square value of the vibration acceleration signals and the value of a preset index are determined. And determining the vibration severity level of the preset acquisition position of the vehicle-mounted platform according to the mean square value of the vibration acceleration, the value of the preset index and the preset corresponding relation. The preset corresponding relation is a preset corresponding relation among a preset vibration acceleration mean square value, a preset index value and a preset vibration severity grade.

The mean square value of the vibration acceleration represents the total power of the vibration acceleration signal, the magnitude of the preset index represents the flatness of the power spectral density of the vibration acceleration signal, so that the mean square value of the vibration acceleration and the value of the preset index can reflect the distribution condition of power in the power spectral density of the vibration acceleration signal, and the distribution condition of power in the power spectral density of the vibration acceleration signal can reflect the vibration condition of the preset acquisition position on the vehicle-mounted platform.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 (a) is a graph of normalized power components disclosed in an embodiment of the present application;

FIG. 1 (b) is a schematic diagram of cumulative distribution of normalized power components disclosed in the embodiments of the present application;

FIG. 2 is a flow chart of a method for classifying vibration severity of an on-board platform according to an embodiment of the present application;

FIG. 3 is a flow chart of yet another method of grading vibration severity of an on-board platform disclosed in an embodiment of the present application;

FIG. 4 is a flow chart of a method for determining vibration severity level based on triaxial vibration acceleration signals at different velocity conditions according to an embodiment of the present application;

FIG. 5 is a schematic diagram of a velocity profile disclosed in an embodiment of the present application;

FIG. 6 is a flow chart of yet another method for determining vibration severity level based on triaxial vibration acceleration signals at different velocity conditions according to an embodiment of the present application;

fig. 7 is a schematic diagram of three axial vibration acceleration signals collected at a GPS support of a vehicle platform according to an embodiment of the present disclosure;

fig. 8 is a schematic diagram of distribution of vibration amplitude of an X-axis vibration acceleration signal collected at a GPS support of a vehicle-mounted platform according to an embodiment of the present application;

fig. 9 is a schematic power spectrum density diagram of an X-axis vibration acceleration signal collected at a GPS support of a vehicle-mounted platform according to an embodiment of the present application;

FIG. 10 is a schematic diagram of power spectral densities of a Y-axis vibration acceleration signal and a Z-axis vibration acceleration signal acquired at a GPS support of a vehicle-mounted platform according to an embodiment of the present application;

fig. 11 is a schematic diagram of stacking three axial power spectrums collected at a GPS support of a vehicle-mounted platform to obtain a total power spectrum according to the embodiment of the present application;

fig. 12 is a schematic diagram of a power spectrum obtained by taking the maximum value of three axial power spectrums collected at a GPS support of a vehicle-mounted platform according to an embodiment of the present application;

fig. 13 is a schematic structural diagram of a device for determining vibration severity level of an on-board platform according to an embodiment of the present application.

Detailed Description

The vibration conditions at different positions of the vehicle-mounted platform are different, and the vibration conditions at the same position in different axial directions are different. In this embodiment of the present application, the vibration condition at the preset collection position needs to be analyzed, and specifically, the preset collection position may be a vibration excitation point that affects the structure of the vehicle-mounted platform, or affects the stability or precision of the device on the vehicle-mounted platform, or is a device installation position point.

Specifically, an acceleration sensor is installed at a preset acquisition position, and the installed acceleration sensor can be a single-axis vibration acceleration sensor or a triaxial vibration acceleration sensor. The single-axis vibration acceleration sensor is used for collecting vibration acceleration signals in a single axial direction on a preset collecting position, and the three-axis vibration acceleration sensor is used for collecting vibration acceleration signals in three axial directions on the preset collecting position. Whether the vibration acceleration sensor is a single-axis vibration acceleration sensor or a triaxial vibration acceleration sensor, vibration acceleration signals at preset sampling positions are collected according to preset sampling frequencies, and for convenience of description, the vibration acceleration signals collected by the single-axis vibration acceleration sensor are called single-axis vibration acceleration signals, and the three axial vibration acceleration signals collected by the triaxial vibration acceleration sensor are called triaxial vibration acceleration signals. The vibration acceleration signal in any one axial direction is a two-dimensional signal with time and acceleration as variables.

In the embodiment of the application, the precondition is that the vibration acceleration signal is a smooth random process. Because the vibration generated by the vehicle-mounted platform when the vehicle-mounted platform runs on a single road surface at a constant speed is random vibration, the acquired vibration acceleration signal is a stable process in a time domain. However, in practice, the collected vibration acceleration signal may exhibit a non-stationary state due to uncertainty of an emergency of the running state of the vehicle-mounted platform, etc. In this embodiment, the vibration acceleration signal collected by the vibration acceleration sensor may be divided into multiple segments, and each segment of divided vibration acceleration signal may be regarded as a stable random process, so as to ensure that the vibration acceleration signal processed by the embodiment of the present application is a stable random process.

The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.

In this embodiment, the vibration severity level is determined based on the frequency domain characteristics of the vibration acceleration signal.

Assuming that the vibration acceleration signal acquired by the vibration acceleration sensor has a sampling frequency f _s Obtaining N sampling points x ₀ ,x ₁ ,...,x _N-1 . Performing discrete Fourier transform to obtain a main value sequence shown in the following formula (1):

wherein X is _k Representing frequency

Complex components at that point. Let N be an even number. From the result of the discrete fourier transform, the power spectral density of the signal at each frequency can be calculated using the following equation (2).

Wherein the power spectral density reflects the mean square value of the time domain vibration acceleration signal

(i.e. total power) within the frequency range under consideration +.>

And the total power of the time domain vibration acceleration signal is calculated as shown in the following formula (3):

due to the sampling frequency f _s According to actual vehiclesThe carrier and the frequency band range of interest are determined in advance, so that the frequency band information is obtained when the power spectrum density analysis is performed

The determination of vibration severity is not critical, and the shape of the power spectral density will be the focus of the vibration severity analysis. Wherein, the power spectral density reflects the distribution of the total power at different frequencies: for a given +. >

The flatter the power spectral density function, the more uniform the distribution of power over the various frequency components, and the less likely a large proportion of the components will occur over some components. Conversely, if the power is concentrated in a certain (several) narrow frequency band, the greater the risk is. Therefore, it is considered whether the power spectral density is flat within a given frequency band, and the severity of the vibration acceleration signal is determined therefrom. According to this idea, the following method for determining the severity level is proposed.

For ease of description, consider normalized power components

Wherein->

A function shown in the following formula (4) is defined:

F _s (s) is given in

Upper->

At a frequency component, the number of frequency components having a power spectral component value below a certain power component level sProportion of (2) wherein%>

Is indicated at->

Upper->

The number of frequency components at which the power component value is below a certain level s, i.e. at +.>

Upper->

At any one of the frequency components, if the value of the power spectrum component at that frequency component is less than s, the value at that frequency component is 1.

Specifically, F _s The schematic diagram of(s) is shown in fig. 1 below, fig. 1 comprising two diagrams, fig. 1 (a) and fig. 1 (b) in this order from top to bottom. Wherein FIG. 1 (a) shows a normalized distribution of a certain power component (i.e. S _k P PSD), it has components at 10 frequencies of 0 to 9. Given a certain power component level s=0.8, it can be seen that the power spectral component level at 5 frequencies total of 2,3,4,5,6 is less than 0.8; accordingly, at the power component level F _s (0.8) =0.5, indicating that the power spectrum component value at the frequency component of 50% in total is smaller than 0.8. Similarly, F at any s can be given _s The(s) value is shown in FIG. 1 (b). F (F) _s (s) defines the cumulative distribution of normalized power components, which may be referred to as the distribution function of normalized power components.

If F is to be used _s (S) is regarded as a random variable S _x The random variable is expected to be as shown in equation (5) below:

it can be verified that we define F as above _s (s) satisfy

Thus, the normalized power component S within the considered frequency bin _k Regarded as a sampling of a random variable, F _s (s) corresponds to the corresponding empirical distribution function, and the sample mean value corresponds to the signal

(this is also referred to herein as S _k For normalizing the power component). To measure the flatness of the normalized power component distribution, S as shown in the following equation (6) can be used _k Is used for sample variance quantization:

for sampled signals of different powers, to ensure lateral comparability, the coefficient of variation shown in the following formula (7) is considered

Thus, a binary group describing the frequency domain distribution of the vibration acceleration signal can be obtained

According to the above analysis, for a given

CV[S _x ]The smaller the power spectral density function, the flatter the shape, the less likely the power is concentrated at a certain location, and the less likely the power is concentrated at a certain frequency due to the energy concentrationCausing some undesirable losses. Of course, is->

Smaller indicates lower power and less vibration severity. Thus, by +.>

As a main index, CV [ S ] _x ]As a second index, in the form of a binary group +.>

As a comprehensive index describing the severity of vibration. For two different vibration environments, +.>

The large vibration environment is more severe; when->

CV [ S ] when the same _x ]The large vibration environment is more severe.

Considering that the frequency range is deterministic, the mean square value (rather than the power spectral density) is directly employed as a grading criterion for the vibration power level to intuitively characterize the power level of the signal. Referring to the existing national standard and actually measured vibration data, in this embodiment, the vibration level is first divided into five levels according to the mean square value, and the vibration of each level is further divided into four types according to the variation coefficient of the normalized power component, as shown in table 1.

TABLE 1

In practice, for a vehicle-mounted platform, the absolute vibration grading criterion should be determined by comprehensively considering vibration amplitude ranges of the vehicle-mounted platform in different environments and at different positions in a vehicle, and considering acceleration limit values of equipment and passengers (electronic products and passengers) in the vibration grading criterion.

In this embodiment of the present application, the principle of determining the severity level of the vehicle-mounted platform may be adopted to process the uniaxial vibration acceleration signal to obtain the severity level of the vehicle-mounted platform vibration, or process the triaxial vibration acceleration signal to obtain the severity level of the vehicle-mounted platform vibration. Specifically, first, vibration acceleration signals in three directions are integrated based on vibration acceleration signals in three axial directions, and then, a vibration severity level is determined based on the integrated vibration acceleration signals. Specifically, the embodiments of the present application provide two methods, namely, a sum method and a maximum method, and detailed descriptions are given in the embodiment corresponding to fig. 2 for the specific implementation of the sum method, and detailed descriptions are given in the embodiment corresponding to fig. 3 for the specific implementation of the maximum method.

Fig. 2 is a method for determining vibration severity level of an on-board platform according to an embodiment of the present application, including the following steps:

s201, acquiring a triaxial vibration acceleration signal acquired by a triaxial vibration acceleration sensor.

In this step, the triaxial vibration acceleration sensor samples a preset acquisition position at a preset sampling frequency to obtain a triaxial vibration acceleration signal, which may specifically be (x ₀ ,y ₀ ,z ₀ ),...,(x _N-1 ,y _N-1 ,z _N-1 )。

In the present embodiment, the vibration severity level is determined on the premise that the amplitude in the vibration acceleration signal in each axial direction follows a normal distribution with a mean value of 0.

S202, determining the mean square value of the vibration acceleration of the triaxial vibration acceleration signal.

In the present embodiment, the vibration acceleration signal at the i-th timing

Wherein the acceleration sensor is acquired at the momentThe signal on the XYZ axis is (x) _i ,y _i ,z _i ) Specifically, the signal at the ith moment on the X axis takes the value X _i The signal value at the ith moment on the Y axis is Y _i The signal value at the ith moment on the Z axis is Z _i 。

Vibration acceleration signal at N times

Mean square value +.>

The calculation formula of (2) is shown in the following formula (8):

the calculation method of the mean square value of the N vibration acceleration signals in the X axis is shown in the following formula (9):

the mean square value of the N vibration acceleration signals in the Y-axis direction is calculated as shown in the following formula (10):

the mean square value of the N vibration acceleration signals in the Z-axis direction is calculated as shown in the following formula (11):

From the formula (8), the formula (9), the formula (10) and the formula (11), the formula shown in the following formula (12) can be obtained:

it can be seen that the light source is,

the total power corresponding to the vibration acceleration in three degrees of freedom is actually given, so in this embodiment, the mean square value of the vibration acceleration signal in each axial direction is calculated, and the sum of the mean square values of the vibration signals in the three axial directions is used as the mean square value of the vibration acceleration signal in the three axial directions.

S203, performing Fourier transform on each axial vibration acceleration signal to obtain the power spectrum density of each axial vibration acceleration signal.

Specifically, the fourier transform process of the vibration acceleration signal is a prior art, and will not be described herein. After fourier transforming the vibration acceleration signal, the power spectral densities of the vibration acceleration signal are obtained, and in this embodiment, the power spectral densities of the vibration acceleration signals in three axial directions are expressed as: s is S _xx (f)、S _yy (f) And S is _zz (f) Wherein, the method comprises the steps of, wherein,

the power spectral density reflects the distribution of power at different frequencies, and the shape of the power spectral density curve is an important basis for determining the vibration severity level. In particular, the flatter the shape of the power spectral density curve, the more uniform the power distribution across the frequencies, the less likely a large proportion of power will occur at certain frequencies, and the less likely the vibration will be greater (i.e., the vibration severity level will be higher). Conversely, the more spikes in the power spectral density indicate that the power is concentrated in one or more narrower frequency bands, at which time the greater the probability of vibration.

As the power spectrum density of the vibration acceleration signal comprises a plurality of frequency bands, experiments prove that [0, f _s ]The power spectral density corresponding to this frequency band has a good effect on determining the vibration severity level of the present embodiment, and therefore, in the present embodimentIn the examples, for [0, f _s ]The power spectral density corresponding to this band is analyzed. Of course, in practical application, it may be determined according to practical situations, which frequency band is required to be analyzed, and the value of the frequency band used for determining the vibration severity level is not limited in this embodiment.

S204, taking the sum of three powers corresponding to the same frequency in the power spectral densities in each axial direction as the power of the frequency to obtain a first comprehensive power spectral density.

In the present embodiment, the vibration acceleration signals in the three axial directions are acquired with the same sampling frequency, and therefore, the frequencies in the power spectral densities in the three axial directions are the same.

In this step, for any one frequency, the sum of three powers corresponding to the frequency in the power spectral densities in the three axial directions is used as the power of the frequency, and at this time, the power corresponding to each frequency in the power spectral densities in the three axial directions can be calculated, that is, the correspondence between the frequency and the power can be obtained, and the correspondence between the frequency and the power obtained in this step is referred to as a first integrated power spectral density.

Specifically, an expression of the sum of three powers corresponding to any one frequency is determined, as shown in the following formula (13):

wherein S is _aa (f _j ) Representing the frequency f _j Corresponding three powers S _xx (f _j ),S _yy (f _j ),S _zz (f _j ) And (3) summing. In this embodiment, the obtained first integrated power spectral density is S _aa (f) And (3) representing.

S205, determining a variation coefficient according to the first comprehensive power spectral density and the mean square value of the vibration acceleration.

In the present embodiment, the variance of the power spectrum is calculated in a manner shown by the following formula (14):

in the formula Var [ S ] _x ]The first variance is represented, in particular the variance of the normalized power component, where the normalized power component refers to the distribution of power at different frequency levels.

For sampled signals of different powers, to ensure lateral comparability, consider the coefficient of variation shown in the following equation (16):

wherein the coefficient of variation is a dimensionless magnitude.

S206, determining the vibration severity level of the preset position of the vehicle-mounted platform according to the vibration acceleration mean square value, the variation coefficient and the preset vibration severity level table.

In this step, the vibration severity level to which the vibration acceleration mean square value and the variation coefficient belong in the vibration severity level table is determined from the calculated vibration acceleration mean square value, variation coefficient, and the vibration severity level table provided in table 1.

The embodiment corresponding to fig. 2 is a process of determining the vibration severity level of the vehicle platform by using the triaxial vibration acceleration signal. For the uniaxial vibration acceleration signal, the mean square value of the vibration acceleration is calculated by simply using the uniaxial vibration acceleration signal. The power spectral density of the uniaxial vibration acceleration signal is calculated, the operation of summing the power spectral density is not needed, the variation coefficient is calculated only according to the power spectral density and the mean square value of the vibration acceleration, specifically, the variation coefficient is calculated, and the vibration severity level of the vehicle-mounted platform is determined according to the mean square value of the vibration acceleration, the variation coefficient and the preset corresponding relation, which are the same as those of the triaxial vibration signal, and the description is omitted here.

Fig. 3 is a schematic diagram of another method for classifying vibration severity of an on-board platform according to an embodiment of the present application, including the following steps:

s301, acquiring a triaxial vibration acceleration signal acquired by a triaxial vibration acceleration sensor.

The specific content of this step may refer to S201 in the corresponding embodiment of fig. 2, which is not described herein.

S302, performing Fourier transform on each axial vibration acceleration signal to obtain the power spectral density of each axial vibration acceleration signal.

Specifically, the fourier transform process of the obtained vibration acceleration signal in any one axial direction is the same as the principle of S203 in the embodiment corresponding to fig. 2, and will not be described herein.

In the present embodiment, the power spectral densities of the vibration acceleration signals in the three axial directions are expressed as: s is S _xx (f)、S _yy (f) And S is _zz (f) Wherein, the method comprises the steps of, wherein,

s303, taking the maximum power of the three powers corresponding to the same frequency in the power spectral densities in each axial direction as the power of the frequency to obtain a second comprehensive power spectral density.

In the present embodiment, since the three axial vibration acceleration signals are sampled by the triaxial vibration acceleration sensor with the same sampling frequency, the frequencies in the power spectral densities in the three axial directions are the same.

In this step, for any one frequency, the maximum power value of the three powers corresponding to the frequency among the three axial power spectral densities is used as the power of the frequency, the power of each frequency among the three axial power spectral densities is obtained, and the correspondence between the obtained frequency and the power at this time is referred to as a second integrated power spectral density.

Specifically, an expression of the maximum power of any one frequency among the corresponding three powers is determined, as shown in the following formula (17):

Wherein S is _uu (f _j ) Representing the frequency f _j Corresponding three powers S _xx (f _j ),S _yy (f _j ),S _zz (f _j ) Is set at the maximum power of (a). In this embodiment, the second integrated power spectral density obtained is S _uu (f) And (3) representing.

In this embodiment, for three power spectral densities corresponding to the three axial vibration acceleration signals, for any one frequency of the three power spectral densities, the maximum power of the three powers corresponding to the frequency in the three power spectral densities is used as the power of the frequency in the integrated power spectral density, so as to obtain a second integrated power spectral density. The obtained second comprehensive power spectrum density is an envelope spectrum of three power spectrum densities corresponding to the three axial directions, and the power of the envelope spectrum is larger than the power of any one axial direction. The envelope spectrum characterizes the maximum power that the electronic device on the vehicle-mounted platform may be subjected to in any one of the three XYZ axes, and therefore, the second integrated power spectral density may be used as the power spectral density of the vibration acceleration signals in the three axes.

S304, determining a mean square value and a variation coefficient of the vibration acceleration according to the second comprehensive power spectral density.

Specifically, the mode of determining the mean square value of the vibration acceleration according to the second integrated power spectral density is shown in the following formula (18):

In the method, in the process of the invention,

representing a second integrated power spectral density, +.>

Representing mean square value of vibration acceleration at second integrated power spectral density。

To ensure unity, the variance of the normalized power component may also be calculated as shown in equation (19) below.

In the method, in the process of the invention,

representing a second integrated power spectral density Var [ S ] _x ]For the second variance, the variance of the normalized power spectral component is represented,/->

The mean square value of the vibration acceleration is shown.

For sampled signals of different powers, to ensure lateral comparability, consider the coefficient of variation shown in the following equation (20):

wherein the coefficient of variation is a dimensionless magnitude.

S305, determining the vibration severity level of the preset position of the vehicle-mounted platform according to the vibration acceleration mean square value, the variation coefficient and the preset vibration severity level table.

In this step, according to the calculated mean square value and variation coefficient of the vibration acceleration and the vibration severity classification table provided in the embodiment of the present application, the vibration severity class to which the mean square value and variation coefficient of the vibration acceleration belong in the vibration severity classification table is determined.

In the embodiments corresponding to fig. 2 and 3, the mean square value of the vibration acceleration signal and the coefficient of variation of the normalized power component are calculated, respectively, where the mean square value of the vibration acceleration represents the total power of the triaxial vibration acceleration signal. The coefficient of variation of the normalized power component represents the degree of flatness of the power spectral density of the triaxial vibration acceleration signal. In the embodiment of the present application, only the flatness of the power spectrum density of the triaxial vibration acceleration signal expressed by using the variation coefficient of the normalized power component is given, in practice, other indexes may also be adopted, for convenience in description, the preset index is referred to as a preset index, as long as the preset index represents the flatness of the power spectrum density of the triaxial vibration acceleration signal, and the specific content of the preset index is not limited in this embodiment.

The above embodiments corresponding to fig. 3 are all processes of determining the vibration severity level of the vehicle platform by using the triaxial vibration acceleration signals. For the uniaxial vibration acceleration signal, calculating the power spectral density of the uniaxial vibration acceleration signal, and not performing maximum operation on the power spectral density, only calculating the mean square value and the variation coefficient of the vibration acceleration according to the power spectral density, specifically, calculating the mean square value and the variation coefficient of the vibration acceleration, and determining the vibration severity level of the vehicle-mounted platform according to the mean square value and the variation coefficient of the vibration acceleration and the preset corresponding relation, which are the same as those of the triaxial vibration signal, and will not be repeated here.

In order to understand the overall vibration response of the vehicle platform, pavement tests are required to be performed at different speeds on different typical pavements. For a given uniform road surface, the vibration response and the spectral variation with travel speed at a location within the vehicle are quite different: although the power of the vibration signal generally increases with an increase in the running speed, the specific functional relationship also varies from case to case; and the variation of each frequency component in vibration along with the running speed is more complex. In addition, the change rule of the vibration response along with the running speed at different positions is different, and the change rule of the vibration response along with the running speed is different for different road surfaces. Thus, the vibrational response of the vehicle platform at a location is affected by the structural characteristics of the vehicle itself, the road surface properties, and the speed of travel.

Assuming that the response conditions of different road conditions and different running speeds are known for a certain position of the vehicle platform, the typical task scene and task profile of the vehicle need to be considered. Only the main purpose and the use scene of the vehicle are determined, the different road conditions possibly experienced by the vehicle during running and the speed change condition during running can be determined, and then the actual vibration level of the vehicle is determined. Based on this information, vibration severity analysis can be performed. Therefore, an element of vibration severity analysis for a specific vehicle is a typical task profile, including a road surface type and a running speed of main running, and in this embodiment of the present application, a speed profile is taken as an example, and a process of determining a vibration severity level of a vibration acceleration signal at a preset collecting position of a vehicle platform is described, specifically, the following embodiments respectively corresponding to fig. 4 and fig. 5.

Fig. 4 is a method for determining a vibration severity level according to a triaxial vibration acceleration signal under different speed conditions according to an embodiment of the present application, including the following steps:

s401, acquiring a speed signal of the vehicle-mounted platform in the running process, and acquiring a triaxial vibration acceleration signal acquired by a triaxial vibration acceleration sensor on the vehicle-mounted platform.

In this embodiment, a speed sensor may be installed on the vehicle platform, where the speed sensor is used to measure the speed of the vehicle platform at each moment in the running process of the vehicle platform, and for convenience of description, the corresponding relationship between the running speeds of the vehicle platform at each moment measured by the speed sensor is referred to as a speed signal.

In the step, a triaxial vibration acceleration signal acquired by a triaxial vibration acceleration sensor on the vehicle-mounted platform is also acquired. Specifically, the process of acquiring the triaxial vibration acceleration signal may refer to S201 in the embodiment corresponding to fig. 2, which is not described herein.

S402, determining information of each speed condition in the speed signal.

In this embodiment, the vehicle-mounted platform may first go through a short acceleration stage, then go through a long constant velocity stage, and finally go through a deceleration stage after reaching the purpose in the actual driving process, as shown in a speed curve schematic diagram in fig. 5.

In fig. 5, the abscissa indicates time, and the ordinate indicates the magnitude of speed, and it can be seen from fig. 5 that the speed profile is changed in such a way that acceleration is performed first, then uniform speed is performed, and finally deceleration is performed. It should be noted that the speed profile shown in fig. 5 is merely an example, and in practice, the speed signal of the vehicle platform may be obtained by connecting a plurality of speed profiles in fig. 5 in series during the actual running process of the vehicle platform.

Since the speed is changed during the running of the vehicle platform, in this embodiment, the speed increasing process, the speed unchanged process, and the speed decreasing process are all referred to as a speed changing process. Any one speed change process or a plurality of continuous speed change processes in the speed signals of the running process of the vehicle-mounted platform are collectively called a speed condition.

In this embodiment, the speed signal of the vehicle platform is divided into a plurality of speed conditions according to the sequence from front to back of the time. In the present embodiment, the m speed conditions into which the speed signal of the vehicle-mounted platform is divided are referred to as a speed condition set, and c is adopted ₁ ,c ₂ ,...,c _m Representation, wherein c _j Represents any one speed condition, where j=1, 2,..m.

In this step, for each determined speed condition, information about the speed condition is further determined, where the information may include: the starting time and the ending time of the speed condition are the time length and the duty ratio. The time length of any one speed condition is the time length from the starting time of the speed condition to the ending time of the speed condition, and the time length of any one speed condition is the proportion of the total time length of the whole speed signal.

Assuming that the speed signal during the traveling of the vehicle platform is a speed curve as shown in fig. 5, in the present embodiment, the speed increasing process may be used as the first speed condition c ₁ Taking the constant speed process as a second speed condition c ₂ The speed reduction process is taken as a third speed condition c ₃ . Wherein the first speed condition c ₁ The information of (a) is [ t ] ₁ ,t ₂ ]The duration is as follows

Wherein T represents the total duration of the speed profile of FIG. 5, the second speed condition c ₂ The information of (a) is [ t ] ₃ ,t ₄ ]The duration is +.>

Third speed condition c ₃ The information of (a) is [ t ] ₅ ,t ₆ ]The duration is +.>

S403, respectively determining vibration acceleration signal segments corresponding to the time of each speed condition in the speed condition set from the vibration acceleration signals in each axial direction, and determining the duration duty ratio of each determined vibration acceleration signal segment.

For any one axial vibration acceleration signal S of the triaxial vibration acceleration signals, vibration acceleration signal segments indicated by the starting time and the ending time in the information of each speed condition are determined. Specifically, for any one of the velocity condition c in the velocity condition set ^j In the vibration acceleration signal S in the axial direction, a vibration acceleration signal segment composed of vibration acceleration signals of a time segment composed of a start time and an end time in the information of the speed condition is determined. And uses the vibration acceleration signal section as a vibration acceleration signal section S corresponding to the speed condition ^j And takes the time length of the speed condition as the vibration acceleration signal section S ^j The duration of (2) is P ^j At this time, c ^j 、S ^j And P ^j The two are corresponding.

Thus, with the set of speed conditions c ¹ ,c ² ,...,c ^m The corresponding vibration acceleration signal sections are S in turn ¹ ,S ² ,...,S ^m And a set of velocity conditions c ¹ ,c ² ,...,c ^m The corresponding time length proportion of the vibration acceleration signal sections is P in turn ¹ ,P ² ,...,P ^m . For convenience of description, it will be associated with the velocity condition set c ¹ ,c ² ,...,c ^m The corresponding set of vibration acceleration signal segments is called vibration acceleration signal segment set, and will be associated with speed condition set c ¹ ,c ² ,...,c ^m The corresponding set of the duration duty ratio of the vibration acceleration signal segments is called a vibration acceleration signal segment duration duty ratio set. The speed condition set, the vibration acceleration signal segment set and the vibration acceleration signal segment duration duty ratio set have corresponding relations.

In this step, for the vibration acceleration signal in the X-axis direction, the vibration acceleration signal segment set in the X-axis direction is expressed as

The corresponding set of the time length proportion of the vibration acceleration signal section in the X-axis is expressed as +.>

For the vibration acceleration signal in the Y-axis, the set of vibration acceleration signal segments in the Y-axis is denoted +.>

The corresponding set of the time length proportion of the vibration acceleration signal section in the Y-axis is expressed as +. >

For the vibration acceleration signal in the Z-axis, the set of vibration acceleration signal segments in the Z-axis is denoted +.>

The time length duty ratio set of the vibration acceleration signal section in the Z axis is represented as P _z ¹ ,P _z ² ,...,P _z ^m 。

The purpose of the above-mentioned S402 to S403 is: according to the starting time and the ending time of each speed condition in the information of the preset speed condition set, respectively segmenting each axial vibration acceleration signal to obtain a vibration acceleration signal segment set in each axial direction.

S404, determining the power spectral density of each vibration acceleration signal segment in each axial vibration acceleration signal segment set.

For any axial direction, fourier transform is performed on each vibration acceleration signal segment in the vibration acceleration signal segment set of the axial direction to obtain the power spectral density of each vibration acceleration signal segment in the vibration acceleration signal segment set of the axial direction, and for convenience of description, the power spectral density of any vibration acceleration signal segment in the vibration acceleration signal segment set of the axial direction is referred to as the power spectral density segment of the vibration acceleration signal segment. Further, a set of power spectral density segments corresponding to the axial vibration acceleration signal is obtained.

Specifically, in this step, for the vibration acceleration signal in the X-axis direction, the vibration acceleration signal segments in the X-axis direction are collected as

The corresponding set of power spectral density segments is +.>

For the vibration acceleration signal in the Y-axis direction, the vibration acceleration signal segments in the Y-axis direction are assembled as +.>

The corresponding set of power spectral density segments is +.>

For the vibration acceleration signal in the Z-axis direction, the vibration acceleration signal segments in the Z-axis direction are assembled as +.>

The corresponding set of power spectral density segments is +.>

S405, calculating the comprehensive power spectrum density of each axial direction.

Specifically, in this step, the integrated power spectral density in each axial direction is calculated using the following formula (21):

wherein S (f) represents the integrated power spectral density in any one axial direction, S ^j (f) A j-th vibration acceleration signal segment, P, in the vibration acceleration signal segment set representing the axial direction ^j Representing the duration duty cycle of the j-th vibration acceleration signal segment in the set of axial vibration acceleration signal segments.

Specifically, in this step, the integrated power spectral density of the X-axis is

The integrated power spectral density of the Y-axis is +.>

The integrated power spectral density of the X-axis is +.>

S406, determining the comprehensive power spectral density according to the comprehensive power spectral density of each axial direction to obtain a third comprehensive power spectral density.

In this step, there are two ways to determine the third integrated power spectral density according to the integrated power spectral density in each axial direction, the first one: the specific implementation manner of determining the maximum power value in the three powers corresponding to the same frequency in the integrated power spectrum density in each axial direction and using the determined maximum power value as the power of the frequency to obtain the third integrated power spectrum density is the same as S303 in the embodiment corresponding to fig. 3, and will not be described herein. Second kind: the sum of three powers corresponding to the same frequency in the integrated power spectrum densities in each axial direction is determined, and the determined sum value is used as the power of the frequency to obtain a third integrated power spectrum density, and a specific implementation manner is the same as S204 in the embodiment corresponding to fig. 2, which is not described in detail herein.

S407, determining a mean square value and a variation coefficient of the vibration acceleration according to the third comprehensive power spectral density.

Specifically, the principle of determining the mean square value and the coefficient of variation of the vibration acceleration is the same as that of S304 in the embodiment corresponding to fig. 3, and will not be described here again.

In this step, the mean square value of the vibration acceleration is determined according to the third integrated power spectral density, and a third variance is calculated according to the third integrated power spectral density and the vibration acceleration mean, wherein the third variance represents the standard variance of the normalized power component, and the coefficient of variation is determined according to the third variance.

S408, determining the vibration severity level of the preset position of the vehicle-mounted platform according to the vibration acceleration mean square value, the variation coefficient and the preset vibration severity level table.

FIG. 6 is a schematic diagram showing another method for determining vibration severity level according to triaxial vibration acceleration signals under different velocity conditions according to an embodiment of the present application, including the following steps:

S601, acquiring a speed signal of the vehicle-mounted platform in the running process, and acquiring a triaxial vibration acceleration signal acquired by a triaxial vibration acceleration sensor on the vehicle-mounted platform.

Specifically, the implementation process is the same as S401 in the embodiment corresponding to fig. 4, and will not be described here again.

S602, determining information of each speed condition in the speed signal.

Specifically, the implementation process is the same as S402 in the embodiment corresponding to fig. 4, and will not be described here again.

S603, determining vibration acceleration signal segments corresponding to the time of each speed condition in the speed condition set from the vibration acceleration signals in each axial direction, and determining the duration duty ratio of each determined vibration acceleration signal segment.

Specifically, the implementation process is the same as S403 in the embodiment corresponding to fig. 4, and will not be described here again. In the step, a vibration acceleration signal segment set corresponding to each axial vibration acceleration signal and a time length duty ratio set corresponding to each axial vibration acceleration signal are obtained.

The purpose of S602 to S603 is: according to the starting time and the ending time of each speed condition in the information of the preset speed condition set, respectively segmenting each axial vibration acceleration signal to obtain a vibration acceleration signal segment set in each axial direction.

S604, determining the power spectrum density segments of each vibration acceleration signal segment in each axial vibration acceleration signal segment set.

Specifically, the implementation process is the same as S404 in the embodiment corresponding to fig. 4, and will not be described here again.

S605, calculating the comprehensive power spectrum density of the triaxial vibration acceleration signals under each speed condition.

In this step, for any one of the speed conditions, the power spectral density S of the triaxial vibration acceleration signal under that speed condition is calculated ^j (f) The modes of (a) include two types, wherein the first type: the maximum power at the same frequency is taken as the power at the frequency in the power spectral density of the vibration acceleration signal segments in each axial direction, which is the same as the starting time and the ending time of the speed condition. Specifically, the implementation principle is the same as that of S303 in the embodiment corresponding to fig. 3, and will not be described herein. Second kind: the sum of the powers at the same frequency in the power spectrum densities of the vibration acceleration signal segments in the axial direction, which are the same as the starting time and the ending time of the speed condition, is taken as the power at the frequency, and the implementation principle is the same as that of S204 in the embodiment corresponding to fig. 2, and will not be described again here.

And S606, carrying out weighted summation according to the power spectrum density segments of the triaxial vibration acceleration signals under each speed condition to obtain a third comprehensive power spectrum density.

Specifically, in this step, the third integrated power spectral density is calculated using the following equation (22):

wherein S (f) represents a third integrated power spectral density, S ^j (f) Representing the power spectral density, P, of the triaxial vibration acceleration signal at the jth velocity condition ^j The duration duty cycle representing the j-th speed condition.

S607, determining the mean square value and the variation coefficient of the vibration acceleration according to the third comprehensive power spectral density.

Specifically, the principle of determining the mean square value and the coefficient of variation of the vibration acceleration is the same as that of S407 in the embodiment corresponding to fig. 4, and will not be described here again.

S608, determining the vibration severity level of the preset position of the vehicle-mounted platform according to the vibration acceleration mean square value, the variation coefficient and the preset vibration severity level table.

The above-described embodiments corresponding to fig. 4 and 6 describe a process of determining the vibration severity level of the vehicle-mounted platform under the speed condition of the triaxial vibration acceleration signal. For a uniaxial vibration acceleration signal, only the power spectral density of each vibration acceleration signal segment in the uniaxial vibration acceleration signal is calculated, the comprehensive power spectral density is calculated according to the principle of the formula (9), the mean square value and the variation coefficient of the vibration acceleration are determined according to the comprehensive power spectral density, the vibration severity level of the vehicle-mounted platform is determined according to the mean square value and the variation coefficient of the vibration acceleration, specifically, the mean square value and the variation coefficient of the vibration acceleration are determined according to the comprehensive power spectral density, and the principle of determining the vibration severity level of the vehicle-mounted platform according to the mean square value and the variation coefficient of the vibration acceleration is the same as that of the triaxial vibration acceleration signal, and is not repeated here.

The embodiment of the application has the following beneficial effects:

has the beneficial effects that,

In the embodiment of the application, since the mean square value of the vibration acceleration represents the total power of the vibration acceleration signal, and the magnitude of the preset index represents the flatness of the power spectral density of the vibration acceleration signal, the mean square value of the vibration acceleration and the value of the preset index can reflect the distribution condition of the power in the power spectral density of the vibration acceleration signal, so that the vibration severity level of the preset acquisition position on the vehicle-mounted platform is obtained by taking the mean value of the vibration acceleration and the value of the preset index as the standard for determining the vibration severity level of the vehicle-mounted platform, and furthermore, the reference data can be provided for the installation and engineering design of the electronic equipment carried by the vehicle-mounted platform, and the influence of vibration on the electronic equipment is reduced. In addition, the acceleration signal is easy to collect, so that the embodiment of the application has high feasibility and low cost.

Has the beneficial effects of,

In this embodiment, the vibration severity level of the preset collection position on the vehicle-mounted platform is also provided, and the vibration severity level is influenced by the running speed of the vehicle-mounted platform, the road surface property and other aspects. The method comprises the steps of providing information of each speed condition in a speed condition set, segmenting a triaxial vibration acceleration signal, enabling the segmented vibration acceleration signal to be a stable random process, determining the comprehensive power spectral density of each axial vibration acceleration signal segment under each speed condition based on the time length proportion of each speed condition in the speed condition set, obtaining the third comprehensive power spectral density of the vibration acceleration signal under each speed condition, determining the vibration acceleration mean square value and the variation coefficient of a normalized power component based on the third comprehensive power spectral density, and further obtaining the vibration severity level of a preset acquisition position of the vehicle-mounted platform, namely the method for determining the vibration severity level of the preset acquisition position of the vehicle-mounted platform is provided.

In the embodiment of the application, taking a certain vehicle-mounted platform as an example, the method for determining the severity level is shown by combining actually measured vibration acceleration signal data. And a certain vehicle-mounted platform performs pavement test on the concrete pavement and runs at a constant speed of 50 km/h. The vibration condition of the GPS support of the vehicle-mounted platform is monitored, and three axial vibration acceleration signals are respectively obtained, and as shown in fig. 7, the vibration acceleration signals in the three axial directions of the X axis, the Y axis and the Z axis are sequentially obtained from top to bottom.

For the X-axis signal, the distribution of the vibration amplitude is shown in fig. 8. It can be seen that the vibration amplitude obeys a normal distribution with a skewness of 0.103, a kurtosis of 3.36 and a mean square value of 0.1534. The power spectral density of the vibration signal can be obtained by fourier transformation, as shown in fig. 9. It can be seen that the vibration power in the X-axis direction at this point is mainly concentrated in a narrower low frequency band. The standard deviation corresponding to the normalized power component is 1.0844 and the variation coefficient is 7.069. The vibration severity of the measuring point X in the axial direction is classified into 1-2 levels according to the classification criteria given in Table 1 in the examples of the present application.

Similarly, the vibration power spectral densities in the Y-axis and Z-axis directions can be obtained, and as shown in fig. 10, the vibration power spectral densities in the Y-axis direction and the vibration power spectral densities in the Z-axis direction are sequentially shown in fig. 10 in the order from top to bottom. For the Y-axis, the mean square value of the vibration amplitude is 0.2066, the standard deviation of the normalized power component is 1.7803, and the variation coefficient of the normalized power component is 8.617; therefore, it can be judged that the vibration severity level in the Y-axis direction is 1-3. For the Z-axis, the mean square value of the vibration amplitude is 0.9496, the standard deviation of the normalized power component is 5.7348, and the variation coefficient of the normalized power component is 6.0392, so that the vibration severity level in the Z-axis direction is 1-2.

Considering the vibration conditions in three axial directions, the total power spectrum is obtained by superposing the power spectrums in three axial directions by using the summation method described above, as shown in fig. 11. The mean square value of vibration acceleration corresponding to the summation method is 1.3097, the standard deviation corresponding to the normalized power component is 7.326, and the variation coefficient of the normalized power component is 5.5936, so that the vibration severity level at the GPS support obtained according to the summation method is 2-2 levels.

The vibration power spectrum in the three axial directions is obtained by maximizing the vibration power spectrum point by using the maximum method, and the vibration power spectrum shown in fig. 12 is obtained. For the power spectrum density obtained by the maximum value method, the corresponding vibration mean square value can be calculated to be 1.0198, the standard deviation of the normalized power component is 5.8928, and the variation coefficient of the normalized power component is 5.7785. Thus, the maximum method determines a GPS mount vibration severity level of likewise 2-2. Note that the maximum value method gives a mean square value of vibration that is very close to the mean square value of vibration in the Z-axis direction, indicating that the vibration at the GPS stand is mainly determined by the vibration in the Z-axis. The table shows vibration grading in three axial directions and the overall vibration severity level determined using the sum-total method and the maximum method.

In summary, the vibration severity classification results at the GPS mount are shown in table 2:

TABLE 2

Fig. 13 is a device for determining vibration severity level of an on-board platform according to an embodiment of the present application, including: an acquisition module 1301, a first determination module 1302 and a second determination module 1303.

The acquiring module 1301 is configured to acquire a vibration acceleration signal, where the vibration acceleration signal is obtained by sampling a vibration acceleration sensor installed at a preset acquisition position on the vehicle-mounted platform according to a preset sampling frequency. The first determining module 1302 is configured to determine a mean square value of the vibration acceleration and a value of a preset index, where the mean square value of the vibration acceleration represents a total power of the vibration acceleration signal, and the value of the preset index represents a flatness degree of a power spectrum density of the vibration acceleration signal. The second determining module is used for determining the vibration severity level of the preset acquisition position of the vehicle-mounted platform according to the vibration acceleration mean square value, the preset index value and the preset corresponding relation, wherein the preset corresponding relation is the preset vibration acceleration mean square value, the preset index value and the preset corresponding relation between preset vibration severity levels.

Optionally, the vibration acceleration signal is a triaxial vibration acceleration signal, the preset index is a variation coefficient of a normalized power spectrum component, and the normalized power spectrum component refers to distribution of power at different frequency levels. A first determining module 1302, configured to determine a mean square value of the vibration acceleration and a value of a preset index, includes: the first determining module 1302 is specifically configured to calculate a sum of squares of data in each axial vibration acceleration signal, obtain a mean square value of vibration acceleration in each axial direction, determine a power spectral density of each axial vibration acceleration signal, obtain a power spectral density in each axial direction, obtain a first integrated power spectral density by using a sum of powers at the same frequency in each axial power spectral density as a power at the frequency, calculate a variance of a normalized power spectral component as a first variance according to the first integrated power spectral density and the mean square value of vibration acceleration, and use a ratio of an arithmetic square root of the first variance to the mean square value of vibration acceleration as a value of a coefficient of variation.

Optionally, the vibration acceleration signal is a triaxial vibration acceleration signal, the preset index is a variation coefficient of a normalized power spectrum component, and the normalized power spectrum component refers to distribution of power at different frequency levels. A first determining module 1302, configured to determine a mean square value of the vibration acceleration and a value of a preset index, includes: the first determining module 1302 is specifically configured to determine a power spectral density of each axial vibration acceleration signal, obtain a power spectral density of each axial direction, obtain a second integrated power spectral density by using a power maximum value at the same frequency in each axial power spectral density as power at the frequency, calculate a mean square value of vibration acceleration under the second integrated power spectral density according to a relationship between the power spectral density and the total power, calculate a variance of a normalized power spectral component as a second variance according to the second integrated power spectral density and the mean square value of vibration acceleration, and use a ratio of an arithmetic square root of the second variance to the mean square value of vibration acceleration as a variation coefficient of the normalized power spectral component.

Optionally, the vibration acceleration signal is a triaxial vibration acceleration signal, the preset index is a variation coefficient of a normalized power spectrum component, and the normalized power spectrum component refers to distribution of power at different frequency levels. A first determining module 1302, configured to determine a mean square value of the vibration acceleration and a value of a preset index, includes: the first determining module 1302 is specifically configured to segment each axial vibration acceleration signal according to a start time and an end time of each speed condition in the preset speed condition set of information, obtain each axial vibration acceleration signal segment set, determine a power spectrum density of each vibration acceleration signal segment in each axial vibration acceleration signal segment set, obtain each axial power spectrum density set, calculate a composite power spectrum density of each axial vibration acceleration signal segment under a time period corresponding to each speed condition, obtain a composite power spectrum density of the triaxial vibration acceleration signal as a third composite power spectrum density, calculate a vibration acceleration mean square value under the third composite power spectrum density as a vibration acceleration mean square value according to a relation between the power spectrum density and the total power, calculate a variance of a normalized power spectrum component as a third variance according to the third composite power spectrum density and the vibration acceleration mean square value, and calculate a ratio of an arithmetic square root of the third variance to the vibration acceleration mean square value as a variation coefficient of the normalized power spectrum component.

Optionally, the first determining module 1302 is configured to calculate a comprehensive power spectral density of the power spectral density of each axial vibration acceleration section under a time length-to-time ratio corresponding to each speed condition, to obtain a third comprehensive power spectral density of the triaxial vibration acceleration signal, where the third comprehensive power spectral density includes: the first determining module 1302 is specifically configured to respectively perform weighted summation on the power spectral densities of the vibration acceleration signal segments in each axial direction according to the time length duty ratio corresponding to each speed condition, so as to obtain a comprehensive power spectral density in each axial direction, where the weight of the power spectral density of any vibration acceleration signal segment in any axial direction is: and the time length ratio of the speed condition which is the same as the starting time and the ending time of the vibration acceleration signal section is calculated by taking the sum of powers at the same frequency in the integrated power spectrum density of each axial direction as the power at the frequency, or taking the maximum power at the same frequency in the integrated power spectrum density of each axial direction as the power at the frequency, so that the integrated power spectrum density of the triaxial vibration acceleration signal is obtained as a third integrated power spectrum density.

Optionally, the first determining module 1302 is configured to calculate a comprehensive power spectral density of the power spectral density of each axial vibration acceleration section under a time length-to-time ratio corresponding to each of the speed conditions, to obtain a third comprehensive power spectral density of the triaxial vibration acceleration signal, where the third comprehensive power spectral density includes: the first determining module 1302 is specifically configured to take, as the power at the frequency, the sum of powers at the same frequency or the maximum power at the same frequency in the power spectral densities of the vibration acceleration signal segments in the axial direction, which are the same as the start time and the end time of the speed condition, to obtain the integrated power spectral densities of the vibration acceleration signals in the triaxial directions under each speed condition, and respectively perform weighted summation on the integrated power spectral densities of the vibration acceleration signals in the triaxial directions under each speed condition, to obtain a third integrated power spectral density, where the weight of the integrated power spectral density of the vibration acceleration signals in the triaxial directions under any speed condition is: the duration of the speed condition is a ratio.

The functions described in the methods of the present application, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computing device readable storage medium. Based on such understanding, a portion of the embodiments of the present application that contributes to the prior art or a portion of the technical solution may be embodied in the form of a software product stored in a storage medium, comprising several instructions for causing a computing device (which may be a personal computer, a server, a mobile computing device or a network device, etc.) to perform all or part of the steps of the methods described in the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), a magnetic disk, or an optical disk, or other various media capable of storing program codes.

In this specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, so that the same or similar parts between the embodiments are referred to each other.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for determining a vibration severity level of an on-board platform, comprising:

determining the vibration severity level of a preset acquisition position of the vehicle-mounted platform according to the vibration acceleration mean square value, the value of the preset index and the preset corresponding relation; the preset corresponding relation is a preset corresponding relation among a preset vibration acceleration mean square value, a preset index value and a preset vibration severity grade level;

the vibration acceleration signal is a triaxial vibration acceleration signal; the preset index is a variation coefficient of the normalized power spectrum component; the normalized power spectrum component refers to the distribution of power at different frequency levels;

Respectively calculating the square sum of the data in each axial vibration acceleration signal to obtain the mean square value of each axial vibration acceleration; taking the sum of the mean square values of the vibration acceleration of each axial direction as the mean square value of the vibration acceleration; respectively determining the power spectral density of each axial vibration acceleration signal to obtain the power spectral density of each axial direction; taking the sum of the powers at the same frequency in the power spectrum density of each axial direction as the power at the frequency to obtain a first comprehensive power spectrum density; calculating the variance of the normalized power spectrum component as a first variance according to the first comprehensive power spectrum density and the mean square value of the vibration acceleration; taking the ratio of the arithmetic square root of the first variance to the mean square value of the vibration acceleration as the value of the variation coefficient;

or alternatively, the process may be performed,

respectively determining the power spectral density of each axial vibration acceleration signal to obtain the power spectral density of each axial direction; taking the power maximum value at the same frequency in the power spectral density of each axial direction as the power at the frequency to obtain a second comprehensive power spectral density; calculating a mean square value of vibration acceleration under the second comprehensive power spectrum density according to the relation between the power spectrum density and the total power; calculating the variance of the normalized power spectrum component as a second variance according to the second comprehensive power spectrum density and the mean square value of the vibration acceleration; taking the ratio of the arithmetic square root of the second variance to the mean square value of the vibration acceleration as the variation coefficient of the normalized power spectrum component;

Or alternatively, the process may be performed,

respectively segmenting each axial vibration acceleration signal according to the starting time and the ending time of each speed condition in the information of the preset speed condition set to obtain a vibration acceleration signal segment set in each axial direction; respectively determining the power spectral density of each vibration acceleration signal segment in each axial vibration acceleration signal segment set to obtain each axial power spectral density set; calculating the comprehensive power spectral density of each axial vibration acceleration signal section under the time length corresponding to each speed condition respectively to obtain the third comprehensive power spectral density of the triaxial vibration acceleration signal; calculating a vibration acceleration mean square value under the third comprehensive power spectrum density as the vibration acceleration mean square value according to the relation between the power spectrum density and the total power; calculating the variance of the normalized power spectrum component as a third variance according to the third comprehensive power spectrum density and the vibration acceleration mean square value; and taking the ratio of the arithmetic square root of the third variance to the mean square value of the vibration acceleration as the variation coefficient of the normalized power spectrum component.

2. The method according to claim 1, wherein calculating the integrated power spectral density of the power spectral density of each axial vibration acceleration segment under the respective corresponding time duration ratio of each speed condition, to obtain the integrated power spectral density of the triaxial vibration acceleration signal as a third integrated power spectral density includes:

3. The method according to claim 1, wherein calculating the integrated power spectral density of each power spectral density in each axial power spectral density set under the time length-to-time ratio corresponding to each speed condition, to obtain the integrated power spectral density of the triaxial vibration acceleration signal as a third integrated power spectral density includes:

4. A vehicle-mounted platform vibration severity level determination apparatus, comprising:

The second determining module is used for determining the vibration severity level of the preset acquisition position of the vehicle-mounted platform according to the vibration acceleration mean square value, the preset index value and the preset corresponding relation; the preset corresponding relation is a preset corresponding relation among a preset vibration acceleration mean square value, a preset index value and a preset vibration severity grade level;

the first determining module is specifically configured to calculate a sum of squares of each data in each axial vibration acceleration signal, so as to obtain a mean square value of each axial vibration acceleration; taking the sum of the mean square values of the vibration acceleration of each axial direction as the mean square value of the vibration acceleration; respectively determining the power spectral density of each axial vibration acceleration signal to obtain the power spectral density of each axial direction; taking the sum of the powers at the same frequency in the power spectrum density of each axial direction as the power at the frequency to obtain a first comprehensive power spectrum density; calculating the variance of the normalized power spectrum component as a first variance according to the first comprehensive power spectrum density and the mean square value of the vibration acceleration; taking the ratio of the arithmetic square root of the first variance to the mean square value of the vibration acceleration as the value of the variation coefficient;

Or alternatively, the process may be performed,

the first determining module is specifically configured to determine a power spectral density of each axial vibration acceleration signal, so as to obtain a power spectral density of each axial direction; taking the power maximum value at the same frequency in the power spectral density of each axial direction as the power at the frequency to obtain a second comprehensive power spectral density; calculating a mean square value of vibration acceleration under the second comprehensive power spectrum density according to the relation between the power spectrum density and the total power; calculating the variance of the normalized power spectrum component as a second variance according to the second comprehensive power spectrum density and the mean square value of the vibration acceleration; taking the ratio of the arithmetic square root of the second variance to the mean square value of the vibration acceleration as the variation coefficient of the normalized power spectrum component;

or alternatively, the process may be performed,

the first determining module is specifically configured to segment each axial vibration acceleration signal according to a start time and a stop time of each speed condition in information of a preset speed condition set, so as to obtain a vibration acceleration signal segment set in each axial direction; respectively determining the power spectral density of each vibration acceleration signal segment in each axial vibration acceleration signal segment set to obtain each axial power spectral density set; calculating the comprehensive power spectral density of each axial vibration acceleration signal section under the time length corresponding to each speed condition respectively to obtain the third comprehensive power spectral density of the triaxial vibration acceleration signal; calculating a vibration acceleration mean square value under the third comprehensive power spectrum density as the vibration acceleration mean square value according to the relation between the power spectrum density and the total power; calculating the variance of the normalized power spectrum component as a third variance according to the third comprehensive power spectrum density and the vibration acceleration mean square value; and taking the ratio of the arithmetic square root of the third variance to the mean square value of the vibration acceleration as the variation coefficient of the normalized power spectrum component.

5. The apparatus of claim 4, wherein the first determining module configured to calculate a composite power spectral density of the power spectral density of each axial vibration acceleration segment at a time length-to-time ratio corresponding to each of the speed conditions, to obtain a composite power spectral density of the triaxial vibration acceleration signal as a third composite power spectral density includes:

6. The apparatus of claim 4, wherein the first determining module configured to calculate a composite power spectral density of the power spectral density of each axial vibration acceleration segment at a time length-to-time ratio corresponding to each of the speed conditions, to obtain a composite power spectral density of the triaxial vibration acceleration signal as a third composite power spectral density includes: