CN115221633A - VPG-based commercial vehicle load spectrum equivalent method - Google Patents

Abstract

The invention discloses a VPG-based commercial vehicle load spectrum equivalent method, which comprises the following steps: acquiring a test field load spectrum; comparing and analyzing the data of each test signal, wherein the damage from each load to full load is equivalent; obtaining a VPG simulation load spectrum; equivalently optimizing load spectrum damage; and outputting the equivalent load spectrum. The method solves the benchmarking problem of simulation data and test data under the condition that the load variation range of the commercial vehicle is large, shortens the workload of model benchmarking, has lower difficulty, improves the precision of the load spectrum acquired by the commercial vehicle through a virtual simulation technology, and can better and more accurately predict the fatigue performance of the vehicle.

Description

VPG-based commercial vehicle load spectrum equivalent method

Technical Field

The invention relates to a virtual test field simulation application of a commercial vehicle, in particular to a VPG-based commercial vehicle load spectrum equivalent method.

Background

The load of the whole vehicle under the Virtual test field environment can be predicted based on the joint simulation of the Virtual road surface and the multi-body dynamic model of the whole vehicle, and the technology is generally called as a Virtual test field technology, namely Virtual providing group, which is called as VPG for short. The technology is applied to more passenger vehicles at present, the load range of the commercial vehicle is changed greatly, the road conditions are more complex, the application difficulty of the VPG technology in the aspect of the commercial vehicle is increased, and particularly, how to evaluate the data obtained by simulation and the data of different test load conditions and how to consider the influence of the change range of the load.

In the whole vehicle multi-body dynamic model, some parameters are difficult to obtain by testing and can only be obtained according to empirical values; the tire is used as a primary vibration isolation system which is directly contacted with the road surface in the whole vehicle, and the modeling precision directly influences the precision of the loads of all other parts; due to accuracy problems or actual road surface loss and the like during virtual road surface scanning; the errors of simulation load and actual measurement can be caused, and a large amount of benchmarking work is needed to improve the precision of the whole vehicle model when the errors are reduced, wherein the accuracy comprises parameter measurement, tire testing modeling, performance sensitivity analysis and the like, time and labor are consumed, the workload is large, and the difficulty is high.

Disclosure of Invention

Based on the technical problems existing in the VPG application of the commercial vehicle, the VPG-based load spectrum equivalent method for the commercial vehicle is small in benchmarking workload of simulation data and test data and low in difficulty.

In order to solve the technical problems, the technical scheme of the invention is as follows: a VPG-based commercial vehicle load spectrum equivalent method comprises the following steps:

step 1, acquiring a test field load spectrum:

selecting a durable road surface of a test field, planning a driving sequence, and planning a load channel of each key part attachment point; then carrying out load test on the commercial vehicle, and acquiring load test signals under various loads to obtain a test load spectrum;

step 2, comparing and analyzing the data of each test signal, wherein the damage from each load to full load is equivalent:

firstly, carrying out data processing on load test signal data under each load, and scaling the test signal under each load to be in a full-load state through amplitude or time so that the scaled load damage is kept consistent with the load damage before scaling, thereby forming a test load spectrum under an equivalent full-load working condition;

step 3, obtaining a VPG simulation load spectrum:

sequentially simulating each virtual road surface according to the test route of the actual test field, screening simulation load channels corresponding to each actual test load channel, and obtaining the simulation load spectrum of each simulation load channel;

step 4, equivalent optimization of load spectrum damage:

based on the principle of consistent damage, a genetic algorithm is used for carrying out equivalent iteration on the simulation load damage matrix of the simulation load channel to the test load damage matrix of the test load channel, and SN curve parameters are kept consistent during pseudo-damage calculation;

and 5, outputting an equivalent load spectrum:

and multiplying the simulated load spectrums of the simulated load channels after equivalent iteration by corresponding equivalent coefficients in a time domain according to the road surfaces, and then sequentially connecting the simulated load spectrums in series according to the road surfaces to obtain equivalent load spectrums.

As a preferable technical scheme, the road surface in the step 1 includes n road surfaces of a pothole road, a twisted road, a stone road, a cobblestone road and a washboard road.

Preferably, the load channels of the key part attachment points in the step 1 comprise m load channels of wheel center force, vibration absorber displacement and frame attachment point acceleration.

As a preferable technical scheme, the load test of the commercial vehicle in the step 1 comprises the test under no-load, half-load and full-load working conditions.

As a preferred technical scheme, the step 2 is as follows: and comparing and analyzing the test signal data, wherein the no-load and half-load to full-load damage is equivalent, firstly, data processing is carried out on the load test signal data under each load, and the no-load and half-load signals are scaled to be in a full-load state through amplitude or time, so that the scaled load damage is kept consistent with the load damage before scaling, and a test load spectrum under the equivalent full-load working condition is formed.

As a preferred technical solution, the step 4 of load spectrum damage equivalent optimization includes:

a. respectively carrying out pseudo-damage calculation on the load spectrums of the simulation load channels according to the combined road surface to obtain an mxn variable matrix

Wherein X _mn Representing the damage value of the simulation load channel m on the road surface n;

b. carrying out pseudo-damage calculation on the load spectrum of each test load channel according to the combined road surface to obtain an mx 1 target matrix

Wherein Y is _m Representing the sum of the damage values of the test load channel m on all the road surfaces;

c. based on the multi-objective optimization principle of genetic algorithm, the variable matrix is optimized and iterated to the objective matrix, and the equivalent coefficient is calculated according to the following formula

In the formula (I), the compound is shown in the specification,

is a variable matrix which is a simulation load damage matrix;

is a target matrix, isTesting a load damage matrix;

is a matrix of equivalent coefficients, alpha _n The equivalent coefficient corresponding to the road surface n;

and controlling the solution to be an integer larger than zero, and iteratively solving an equivalent coefficient matrix to obtain a matrix with the solution of n multiplied by 1, namely equivalent coefficients corresponding to n road surfaces.

Due to the adoption of the technical scheme, the invention has the following advantages: 1. the calibration problem of simulation data and test data under the condition of large load variation range of the commercial vehicle is solved, and the obtained load spectrum is closer to an actual test value; 2. compared with the traditional method for improving the precision of the load spectrum, the fatigue damage equivalent iteration method based on the genetic algorithm is more convenient and faster, does not need to excessively pursue the precision of the model, shortens the workload of model alignment, and has lower difficulty; 3. the method avoids errors caused by uncertain factors such as the fact that parameters cannot be directly measured, improves the precision of the load spectrum acquired by the commercial vehicle through the virtual simulation technology, and can better and more accurately predict the fatigue performance of the vehicle.

Drawings

The drawings are only for purposes of illustrating and explaining the present invention and are not to be construed as limiting the scope of the present invention. Wherein:

FIG. 1 is a flow chart of the present invention;

FIG. 2 is a schematic view of a virtual road simulation of a full vehicle model according to the present invention;

FIG. 3 is a schematic illustration of a comparative example of test and simulation data for a left front wheel vertical force tunnel of the present invention on a rock roadway;

FIG. 4 is a schematic diagram of an example of a left front wheel vertical force equivalent rear road combined load spectrum of the present invention.

Detailed Description

Exemplary embodiments according to the present invention are described in detail below with reference to the accompanying drawings. Here, it is to be noted that in the drawings, the same reference numerals are given to the components having substantially the same structure and function, and redundant description about the substantially same components is omitted in order to make the description more concise.

As shown in the figure, the VPG-based commercial vehicle load spectrum equivalent method comprises the following steps:

step 1, acquiring a test field load spectrum:

selecting a durable road surface of a test field, planning a driving sequence, and planning a load channel of each key part attachment point; then carrying out load test on the commercial vehicle, and acquiring load test signals under various loads to obtain a test load spectrum; the pavement comprises n pieces of pavements such as a pothole pavement, a twisted pavement, a stone pavement, a cobblestone pavement and a washboard pavement, and even other pavements needing to be tested; the key part attachment point load channels comprise m load channels such as wheel center force, vibration absorber displacement, frame attachment point acceleration and even other parts needing to be tested; and the preferable load tests of the commercial vehicle for carrying out load tests on the commercial vehicle comprise tests under no-load, half-load and full-load working conditions, and the test consistency and the test uniformity are ensured as much as possible on the premise of ensuring the test accuracy.

Step 2, comparing and analyzing the data of each test signal, wherein the damage from each load to full load is equivalent:

firstly, carrying out data processing on load test signal data under each load, and scaling the test signal under each load to be in a full-load state through amplitude or time so that the scaled load damage is kept consistent with the load damage before scaling, thereby forming a test load spectrum under an equivalent full-load working condition; preferably, each test signal data is compared and analyzed, no-load and half-load damage is equivalent, firstly, data processing is carried out on the load test signal data under each load, the signals of the no-load and the half-load are scaled to be in a full-load state through amplitude or time, the scaled load damage is kept consistent with the load damage before scaling, and simultaneously, mileage distribution under different loads of a test scheme is considered, so that a test load spectrum under an equivalent full-load working condition is formed;

as shown in fig. 2, step 3 is performed, and vpg simulation load spectrum acquisition is performed:

sequentially simulating each virtual road surface according to the test route of the actual test field, screening out simulation load channels corresponding to each actual test load channel, and obtaining the simulation load spectrum of each simulation load channel; FIG. 3 is a schematic diagram of an example of comparing test and simulation data on a stone road for a left front wheel vertical force channel;

step 4, load spectrum damage equivalent optimization:

based on the principle of consistent damage, a genetic algorithm is used for carrying out equivalent iteration on the simulation load damage matrix of the simulation load channel to the test load damage matrix of the test load channel, and SN curve parameters are kept consistent during pseudo-damage calculation; the method comprises the following steps:

a. respectively carrying out pseudo-damage calculation on the load spectrums of the simulation load channels according to the combined pavement to obtain an mxn variable matrix

Wherein X _mn Representing the damage value of the simulation load channel m on the road surface n;

b. carrying out pseudo-damage calculation on the load spectrum of each test load channel according to the combined road surface to obtain an mx 1 target matrix

Wherein Y is _m Representing the sum of the damage values of the test load channel m on all the road surfaces;

c. based on the multi-objective optimization principle of the genetic algorithm, the variable matrix is optimized and iterated to the target matrix, and the equivalent coefficient is calculated according to the following formula

In the formula (I), the compound is shown in the specification,

is a variable matrix which is a simulation load damage matrix;

is a target matrix which is a test load damage matrix;

is a matrix of equivalent coefficients, α _n Equivalent coefficients corresponding to the road surface n;

controlling the solution to be an integer larger than zero, and iteratively solving an equivalent coefficient matrix to obtain a matrix with the solution of n multiplied by 1, namely equivalent coefficients corresponding to n road surfaces;

and 5, outputting an equivalent load spectrum:

and multiplying the simulated load spectrums of the simulated load channels after equivalent iteration by corresponding equivalent coefficients in a time domain according to the road surfaces, and then sequentially connecting the simulated load spectrums in series according to the road surfaces to obtain equivalent load spectrums. Fig. 4 is a schematic diagram of an example, which is a combined load spectrum of the left front wheel vertical force equivalent rear road surface.

The example schematic diagrams shown in fig. 3 and 4 are the testing and simulation processing example of the vertical force channel of the left front wheel on the stone road, the load spectrum of other parts on the vehicle can be based on the VPG simulation without actual testing according to the equivalent method of the invention, the precision is also close to the actual vehicle testing value, and the testing and time alignment are saved.

The method overcomes the defects that the simulation test of the virtual test field of the commercial vehicle is time-consuming and labor-consuming and the key position is difficult to measure, the load spectrum obtained by the fatigue damage consistency principle is closer to the actual test value, the fatigue damage of the simulation load and the actual test field test load to each part of the commercial vehicle is ensured to be consistent as much as possible, and the fatigue performance of the vehicle can be more accurately predicted by applying the damage iteration tool based on the genetic algorithm. The invention provides a key technical basis for enterprises to rapidly research and develop high-quality and high-reliability products and rapidly seize the market.

The foregoing shows and describes the general principles, principal features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims (6)

1. A VPG-based commercial vehicle load spectrum equivalent method is characterized by comprising the following steps:

step 1, acquiring a test field load spectrum:

selecting a durable road surface of a test field, planning a driving sequence, and planning a load channel of each key part attachment point; then carrying out load test on the commercial vehicle, and acquiring load test signals under various loads to obtain a test load spectrum;

step 2, comparing and analyzing the data of each test signal, wherein the damage from each load to full load is equivalent:

firstly, data processing is carried out on load test signal data under each load, and the test signals under each load are scaled to be in a full-load state through amplitude or time, so that the scaled load damage is kept consistent with the load damage before scaling, and a test load spectrum under an equivalent full-load working condition is formed;

step 3, obtaining a VPG simulation load spectrum:

sequentially simulating each virtual road surface according to the test route of the actual test field, screening simulation load channels corresponding to each actual test load channel, and obtaining the simulation load spectrum of each simulation load channel;

step 4, equivalent optimization of load spectrum damage:

based on the principle of consistent damage, a genetic algorithm is used for carrying out equivalent iteration on the simulation load damage matrix of the simulation load channel to the test load damage matrix of the test load channel, and SN curve parameters are kept consistent during pseudo-damage calculation;

and 5, outputting an equivalent load spectrum:

and multiplying the simulation load spectrums of the simulation load channels after equivalent iteration by corresponding equivalent coefficients in a time domain according to the road surfaces, and then serially connecting the simulation load spectrums according to the order of the road surfaces to obtain equivalent load spectrums.

2. A VPG-based commercial vehicle load spectrum equivalence method according to claim 1, characterized in that: the pavement in the step 1 comprises n pavements including a hollow road, a twisted road, a stone road, a cobblestone road and a washboard road.

3. A VPG-based commercial vehicle load spectrum equivalence method according to claim 1, characterized in that: the load channels of the key part attachment points in the step 1 comprise m load channels of the wheel center force, the displacement of the shock absorber and the acceleration of the frame attachment point.

4. A VPG-based commercial vehicle load spectrum equivalence method according to claim 1, characterized in that: the step 1 of testing the load of the commercial vehicle comprises testing under no-load, half-load and full-load working conditions.

5. A VPG-based commercial vehicle load spectrum equivalent method according to claim 4, wherein the step 2 is as follows: and comparing and analyzing the test signal data, wherein the no-load and half-load to full-load damage is equivalent, firstly, the data processing is carried out on the load test signal data under each load, and the signals under the no-load and half-load are scaled to be in a full-load state through amplitude or time, so that the scaled load damage is kept consistent with the load damage before scaling, and a test load spectrum under the equivalent full-load working condition is formed.

6. A VPG-based commercial vehicle load spectrum equivalence method according to any one of claims 1-5, wherein the step 4 load spectrum impairment equivalence optimization comprises:

a. respectively carrying out pseudo-damage calculation on the load spectrums of the simulation load channels according to the combined road surface to obtain an mxn variable matrix

Wherein X _mn Representing artificial load pathsm damage value on the road surface n;

b. carrying out pseudo-damage calculation on the load spectrum of each test load channel according to the combined road surface to obtain an mx 1 target matrix

Wherein Y is _m Representing the sum of the damage values of the test load channel m on all the road surfaces;

c. based on the multi-objective optimization principle of genetic algorithm, the variable matrix is optimized and iterated to the objective matrix, and the equivalent coefficient is calculated according to the following formula

In the formula (I), the compound is shown in the specification,

is a variable matrix which is a simulation load damage matrix;

is a target matrix which is a test load damage matrix;

is a matrix of equivalent coefficients, alpha _n The equivalent coefficient corresponding to the road surface n;

and controlling the solution to be an integer larger than zero, and iteratively solving an equivalent coefficient matrix to obtain a matrix with the solution of n multiplied by 1, namely equivalent coefficients corresponding to n road surfaces.

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