CN115017778A - An Accuracy Evaluation Method of Automobile Durable Dummy Load - Google Patents

Abstract

The invention discloses a precision evaluation method for an automobile durable virtual load, which comprises the following steps: building a simulation environment, setting a simulation vehicle speed, evaluating the virtual load precision, and selecting X, Y, Z three-direction force values of a wheel center in virtual load data as a comparison channel; and carrying out pseudo-damage calculation with X, Y, Z force values of the wheel center obtained by the test of the real endurance test field, and respectively obtaining a vertical pseudo-damage ratio, a longitudinal pseudo-damage ratio and a lateral pseudo-damage ratio as evaluation reference indexes of the virtual load precision. The technical scheme visually judges the length of the time domain signal of the simulation result to ensure the consistency of the load data peak value; the evaluation result represents the precision level of the virtual test field simulation load under the condition of the road condition of the test field; the method of the false damage ratio is adopted, the load characteristic of the whole time history of the data is considered, the defect of the peak value ratio is avoided, and the comparison precision is improved.

Description

An Accuracy Evaluation Method of Automobile Durable Dummy Load

technical field

The invention belongs to the technical field of automobile design, and in particular relates to a precision evaluation method of a dummy load of automobile durability.

Background technique

In the process of vehicle development, the dynamic load input of the vehicle chassis and body is required for the structural durability simulation of the vehicle. In the early stage of development, the dynamic load of the development vehicle could not be accurately obtained according to the test results. Therefore, the motion state of the vehicle on the road was simulated by the method of virtual simulation, and then the dynamic properties of the chassis and the body were simulated and extracted. This method is called the virtual test field method. The establishment of the virtual proving ground simulation method mainly includes the digital road model, the vehicle multi-body dynamics model and the driver model. Through the simulation, the dynamic loads of the connection points of the chassis and the body parts are obtained, which provides basic data for the structural durability simulation of the vehicle. . On the premise of using the virtual proving ground for simulation, the accuracy of the virtual load is particularly important.

The existing methods for evaluating the accuracy of virtual loads are mainly to observe the consistency of simulation data and experimental data in the time domain, such as phase and amplitude. As shown in Figure 1.

Existing methods can evaluate the accuracy of virtual loads to a certain extent, but in the durability simulation of vehicle structures, the ratio of a single peak cannot reflect the accuracy of the entire event history data. The peak ratio accuracy is good, but other peaks and phase errors in the event history are large, and even the overall signal is distorted.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a method for evaluating the accuracy of automobile durable virtual load, so as to solve the problem of the phenomenon of overall signal distortion in the existing method for evaluating the accuracy of virtual load when other peaks and phase errors in the event history are large. .

To achieve the above purpose, the application is achieved through the following technical solutions:

An accuracy evaluation method for a dummy load of automobile durability, comprising the following steps:

S1. Construction of the simulation environment:

Create the corresponding road surface model according to the durability test field, and create the digital test field road surface;

Fitting and generating the Ftire tire model required for the simulation of the virtual proving ground according to the tire test results;

S2, the setting of simulation speed:

Use the multi-body dynamics model of the whole vehicle on the road of the digital test field created in step S1, and use the test speed during the real endurance test field test as the reference speed for driving the virtual vehicle to determine the simulated target vehicle speed;

S3. Evaluation of virtual load accuracy:

On the basis of the multi-body dynamics model in step S3, the road surface of the digital test site is used as the reference road surface, and the simulated target vehicle speed is set. The virtual vehicle will generate force between various components through the process of driving on the reference road surface. transfer, so as to obtain the virtual load data of the relevant parts under specific conditions;

S4. Select the force values in the X, Y, Z directions of the wheel center in the virtual load data of step S3 as the comparison channel; The force value is used to calculate the pseudo-damage, and the vertical pseudo-damage ratio, the longitudinal pseudo-damage ratio and the lateral pseudo-damage ratio are respectively obtained as the evaluation reference index of the virtual load accuracy.

Further, in step S1, the creation method of the road surface model is to establish a 3D digital model of the road surface with equal proportions through the construction drawing for the regular road surface of the durability test site with a specific size, and use the finite element method to discretize the digital model to generate nodes and The unit establishes a 3D equivalent volume pavement model; for the random pavement of the endurance test field, a CRG pavement model is created by laser scanning.

Further, the regular road surface with a specific size in the endurance test field at least includes washboard road, pothole road, resonance road and wave road; the random road surface in the endurance test field at least includes Belgian road or cobblestone road.

Further, the simulated target vehicle speed in step S2 is the speed during the real endurance test field test, and the lower limit and the upper limit are respectively set at 5% and 95% of the vehicle speed, and the target speed is taken as the simulation target in the middle of the upper and lower limits. speed.

Further, the reference road in step S3 selects four types of roads with high frequency and low amplitude, low frequency high amplitude, low frequency low amplitude, and wide frequency and wide amplitude that have the excitation characteristics of the test field road.

Further, the virtual load data in step S3 is corrected data, the data before the wheel enters the characteristic road and after the wheel leaves the characteristic road is deleted, and only the data after the tire enters the characteristic road is retained.

Further, in step S4, the vertical pseudo-damage ratio<2, the longitudinal pseudo-damage ratio<3, and the lateral pseudo-damage ratio<5 are used as the evaluation reference index of the virtual load accuracy.

Compared with the prior art, the beneficial effects of the present invention are:

When evaluating the accuracy of the virtual simulation load of this technical solution, first of all, according to the above-mentioned method for setting the target body of the driving robot, the simulation vehicle speed should be consistent with the test vehicle speed, and the length of the time domain signal of the simulation result should be used for intuitive judgment to ensure the consistency of the load data peak value. .

Through the data analysis of the road in the test field, the pseudo-damage statistics of the virtual load of four typical road conditions of high frequency and low amplitude, low frequency and high amplitude, low frequency and low amplitude, and wide frequency and wide amplitude are selected, and the simulation load of the virtual test field is determined. The accuracy range of the vertical channel pseudo-damage ratio is within 2 times, the longitudinal channel pseudo-damage ratio is within 3 times, and the lateral channel pseudo-damage ratio is within 5 times. The results represent the road conditions of the test site. Accuracy level of virtual proving ground simulation loads.

The method of pseudo-damage ratio is adopted, which takes into account the load characteristics of the entire time history of the data, avoids the defect of peak ratio, and improves the comparison accuracy.

Description of drawings

FIG. 1 is a schematic diagram of a ratio of peak values of time-domain signals adopted in the prior art.

FIG. 2 is a schematic diagram of determining the simulated vehicle speed according to the recorder display diagram of the front wheel wheel speed sensor during the real test field test.

Figure 3 is a schematic diagram of the comparison between the suspension simulation and the test pseudo-damage.

Detailed ways

The technical solutions of the present invention will be described in detail below with reference to the accompanying drawings. The following embodiments are only exemplary, and can only be used to explain and illustrate the technical solutions of the present invention, but cannot be construed as limitations on the technical solutions of the present invention.

The technical solution is based on the virtual road surface, the vehicle dynamics model and the Ftire tire model, and the simulation accuracy is improved by setting the simulated vehicle speed of the robot. At the same time, a typical digital road is selected, and the simulation data is used to calculate the damage. The method of damage ratio is used to quickly evaluate the accuracy of the virtual load.

In this application, the durability test field will be involved. Although the conditions of different durability test fields will be different, they are basically similar. The usual durability test fields include at least: Belgian road, irregular concrete road, longitudinal granite road, Irregularly damaged stone road, pothole road, inclined wave road, rail road, transverse granite road, transverse deceleration marking, asphalt brake road, washboard road, arched granite road, pebble road, twisted road, manhole cover road and resonance road, etc. .

The present application provides a method for evaluating the accuracy of an automobile durable virtual load, comprising the following steps:

S1. Construction of the simulation environment:

For the regular pavement with specific dimensions, such as washboard road, pothole road, resonance road, wave road, etc. in the durability test site, establish a 3D digital model of the road surface in equal proportions through construction drawings, and use the finite element method to discretize the digital model to generate nodes and elements Build a 3D equivalent volume pavement model. Create CRG pavement models through laser scanning of random pavements such as Belgian roads and cobblestone roads.

According to the tire test results, the Ftire tire model required for the simulation of the virtual proving ground is generated.

S2, the setting of simulation speed:

Use the vehicle multi-body dynamics model on the road surface of the digital test site (the vehicle multi-body dynamics model in this application is a conventional model technology for the current vehicle test, and those skilled in the art can select and use the corresponding model according to actual needs. , the model here is a car model, there are corresponding multi-body dynamics models of the whole vehicle for different models, and the applicant will not repeat the description here), and the speed signal during the real test field test is used as the reference speed for driving the virtual vehicle , determine the target speed of the simulation, as shown in Figure 2. The curve is the test speed of the real test field. The lower limit and the upper limit are set at 5% and 95% of the test speed respectively, and the target speed is taken as the input of the driving robot simulation speed in the middle of the upper and lower limits.

S3. Evaluation of virtual load accuracy:

On the basis of the multi-body dynamics model, a virtual road surface (digital test site road surface) is added and used as the reference road surface, and the simulated target speed is set, and the vehicle will pass between the various components during the driving process on the road surface. Generate force transmission, so as to obtain virtual load data of related parts under specific conditions.

Four kinds of roads with high frequency and low amplitude, low frequency and high amplitude, low frequency and low amplitude, and wide frequency and wide amplitude are selected for the analyzed road surface. Such as washboard road, Belgian road, twisted road, long wave road.

S4. The virtual load selects the force values in the three directions of the wheel center X, Y and Z as the comparison channel, and corrects the data, deletes the data before and after the wheel enters the characteristic road, and only retains the data of the tire entering the road to improve the analysis accuracy.

The wheel center force of the virtual data and the test data is calculated as the damage, and the ratio is obtained. Through a lot of experience accumulation, the vertical pseudo-damage ratio is less than 2, the longitudinal pseudo-damage ratio is less than 3, and the lateral pseudo-damage ratio is less than 5 as the virtual load. The reference index for the evaluation of the accuracy is shown in Figure 3, which is a schematic diagram of the comparison between the suspension simulation and the test pseudo-damage.

Although the embodiments of the present application have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, and substitutions can be made in these embodiments without departing from the principles and spirit of the present application and modifications, the scope of this application is defined by the appended claims and their equivalents.

Claims (7)

1. a kind of precision evaluation method of automobile durable virtual load, is characterized in that, comprises the following steps: S1. Construction of simulation environment Create the corresponding road surface model according to the durability test field, and create the digital test field road surface; Fitting and generating the Ftire tire model required for the simulation of the virtual proving ground according to the tire test results; S2, the setting of simulation speed Use the multi-body dynamics model of the whole vehicle on the road of the digital test field created in step S1, and use the test speed during the real endurance test field test as the reference speed for driving the virtual vehicle to determine the simulated target vehicle speed; S3. Evaluation of virtual load accuracy On the basis of the multi-body dynamics model in step S3, the road surface of the digital test site is used as the reference road surface, and the simulated target vehicle speed is set. The virtual vehicle will generate force between various components through the process of driving on the reference road surface. transfer, so as to obtain the virtual load data of the relevant parts under specific conditions; S4. Select the force values in the X, Y, Z directions of the wheel center in the virtual load data of step S3 as the comparison channel; The force value is used to calculate the pseudo-damage, and the vertical pseudo-damage ratio, the longitudinal pseudo-damage ratio and the lateral pseudo-damage ratio are respectively obtained as the evaluation reference index of the virtual load accuracy. 2 . The method for evaluating the accuracy of the dummy load for automobile durability according to claim 1 , wherein in step S1 , the method for creating the road surface model is to establish an equal scale for the regular road surface with a specific size in the durability test field through the construction drawing. 3 . Using the finite element method to discretize the digital model to generate nodes and elements to establish a 3D equivalent volume pavement model; for the random pavement of the durability test site, a CRG pavement model is created by laser scanning. 3. The method for evaluating the accuracy of a dummy load for automobile durability according to claim 2, wherein the regular road surface with a specific size in the durability test field at least includes a washboard road, a pothole road, a resonance road and a wave road; the durability test field The random road surface includes at least Belgian roads or cobblestone roads. 4. The method for evaluating the accuracy of the dummy load of automobile durability according to claim 1, wherein the simulated target vehicle speed in step S2 is at the speed of the real durability test field test, including 5% and 95% of the vehicle speed. Set the lower limit and upper limit of the value respectively, and take the target speed in the middle of the upper and lower limits as the target speed of the simulation. 5. The method for evaluating the accuracy of the vehicle durable virtual load according to claim 1, wherein the reference road in step S3 is selected to have high frequency low amplitude, low frequency high amplitude, low frequency low amplitude that have road excitation characteristics of the test field There are four types of roads: value, broadband and amplitude. 6. The method for evaluating the accuracy of automobile durable virtual load according to claim 1, characterized in that, the virtual load data in step S3 is the corrected data, and the data before the wheel enters the characteristic road and after leaving the characteristic road is deleted, and only The data is retained after the tire enters the characteristic road surface. 7. The method for evaluating the accuracy of the dummy load for automobile durability according to claim 1, wherein in step S4, the vertical pseudo-damage ratio<2, the longitudinal pseudo-damage ratio<3, and the lateral pseudo-damage ratio<5 are used as The evaluation reference index of virtual load accuracy.

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