1. A whole vehicle tire matching method is characterized by comprising the following steps:

1) determining the load of the tire of the whole vehicle according to the vehicle type of the whole vehicle, and selecting the tire type and the tire pressure of the tire according to the load of the tire of the whole vehicle;

2) according to the vehicle type, the tire type and the tire pressure of the whole vehicle, calculating a transfer characteristic curve of a whole vehicle suspension system to obtain a corresponding whole vehicle suspension second-order resonance peak value;

3) judging whether the second-order resonance peak value of the finished automobile suspension meets a set condition or not, and if so, judging that the selected tire type and the tire pressure of the tire are matched with the finished automobile type; the set conditions comprise that the second-order resonance peak value of the whole vehicle suspension is lower than a target value.

2. The vehicle tire matching method according to claim 1, wherein if the set condition is not satisfied, the tire pressure of the tire is adjusted, and whether the second-order resonance peak value of the vehicle suspension corresponding to the adjusted tire pressure satisfies the set condition is judged.

3. The finished automobile tire matching method according to claim 2, wherein if the second-order resonance peak value of the finished automobile suspension corresponding to the adjusted tire pressure does not meet the set condition, whether the unsprung mass of the finished automobile can be reduced is judged, and if the unsprung mass of the finished automobile can be reduced, whether the second-order resonance peak value of the finished automobile suspension corresponding to the adjusted tire pressure and the reduced unsprung mass of the finished automobile can meet the set condition is judged.

4. The finished automobile tire matching method according to claim 3, wherein if the second-order resonance peak value of the finished automobile suspension after the unsprung mass of the finished automobile is reduced still does not meet the set condition, the tire model is adjusted to be a smaller model, and whether the corresponding second-order resonance peak value of the finished automobile suspension after the tire model is adjusted can meet the set condition is judged again.

5. The finished automobile tire matching method according to claim 2, wherein if the second-order resonance peak value of the finished automobile suspension after tire pressure adjustment can meet a set condition, the tire stiffness corresponding to the tire pressure after tire pressure adjustment is calculated, and the tire model and the tire pressure are reselected according to the tire stiffness.

6. The finished automobile tire matching method according to claim 1, wherein the set condition further includes that a ratio of the finished automobile suspension second-order resonance peak value to the target value satisfies a set range.

7. The finished automobile tire matching method according to claim 1, wherein the target value is determined according to a corresponding relationship between the smoothness of the existing finished automobile and the benchmarking vehicle and a finished automobile suspension second-order resonance peak value.

8. The vehicle tire matching method according to claim 1, wherein step 1) is based on a formulaSelecting the model of the tire; in the formula, F₁For tire load-carrying capacity, F₂For the tire load, β is the set tire load rate limit.

9. The vehicle tire matching method according to claim 1, wherein step 1) is based on a formulaSelecting the tire pressure of the tire; in the formula, P_refFor indicating tyre pressure, Q_maxMarking the tyre with the corresponding maximum load-bearing capacity, Q, at the tyre pressure_rRequired tyre carrying capacity for real vehicles, P_rThe inflation pressure required by the real vehicle.

10. A vehicle tyre matching apparatus, comprising a processor and a memory, wherein the processor executes a computer program stored by the memory to implement the vehicle tyre matching method according to any one of claims 1-9.

Background

With the improvement of living standard of people, the requirement on riding comfort is higher and higher, and the tyre is used as the only part for contacting the whole vehicle with the ground, and the vibration isolation characteristic of the tyre greatly influences the driving smoothness. The larger the rigidity of the tire is, the larger the vibration of the tire is caused by uneven road surface, so that the larger the vibration is transmitted to the floor of a vehicle body, meanwhile, the too high rigidity of the tire can lower the unsprung damping ratio, and the unsprung vibration problem is difficult to completely solve only by adjusting the damping force of the shock absorber. Therefore, reasonable matching of tires is very important for the influence of the ride comfort performance of the whole vehicle.

Currently, the selection of tires for a whole vehicle is generally determined on the basis of two aspects, namely the determination of the bearing capacity of the tires and the adjustment determination of the selection of different tires. In the first method, the bearing capacity of the tire is excessive, the rigidity of the tire is selected too much, the whole vehicle can continuously shake under a spring when passing through a poor road surface, and the smoothness performance is difficult to improve. The second method causes resource waste, prolongs the adjustment cycle of the whole vehicle, generally selects tires through subjective feeling, requires experienced adjustment experts to determine, and may cause errors in subjective judgment and poor smoothness.

Therefore, the problem that the smoothness of the whole vehicle is poor in the existing matching method of the whole vehicle tires exists, and the problem that how to improve the smoothness of the whole vehicle matched with the whole vehicle tires needs to be solved urgently is also solved.

Disclosure of Invention

The invention aims to provide a whole vehicle tire matching method and a whole vehicle tire matching device, and aims to solve the problem of poor whole vehicle smoothness performance of the conventional whole vehicle tire matching method.

In order to achieve the aim, the invention provides a method for matching a whole vehicle tire, which comprises the following steps:

1) determining the load of the tire of the whole vehicle according to the vehicle type of the whole vehicle, and selecting the tire type and the tire pressure of the tire according to the load of the tire of the whole vehicle;

2) according to the vehicle type, the tire type and the tire pressure of the whole vehicle, calculating a transfer characteristic curve of a whole vehicle suspension system to obtain a corresponding whole vehicle suspension second-order resonance peak value;

3) judging whether the second-order resonance peak value of the finished automobile suspension meets a set condition or not, and if so, judging that the selected tire type and the tire pressure of the tire are matched with the finished automobile type; the set conditions comprise that the second-order resonance peak value of the whole vehicle suspension is lower than a target value.

In addition, the invention also provides a whole vehicle tire matching device which comprises a processor and a memory, wherein the processor executes a computer program stored by the memory so as to realize the whole vehicle tire matching method.

The beneficial effects are that: the method comprises the steps of firstly realizing primary selection of tire models and tire pressures according to the types of finished vehicles, then calculating the second-order resonance peak value of a finished vehicle suspension frame after the tire models and the tire pressures are installed, and judging whether the selected tires are matched with the finished vehicles or not by taking the second-order resonance peak value of the finished vehicle suspension frame as an index. The invention matches the whole vehicle tyre by taking the second-order resonance peak value of the whole vehicle suspension as an index, so that the tyre matching is more reasonable, and the problem of poor smoothness caused by high tyre rigidity is solved.

Further, in the method and the device, if the set condition is not met, the tire pressure of the tire is adjusted, and whether the second-order resonance peak value of the whole vehicle suspension after the tire pressure is adjusted can meet the set condition is judged.

Further, in the method and the device, if the second-order resonance peak value of the whole vehicle suspension corresponding to the adjusted tire pressure still does not meet the set condition, whether the unsprung mass of the whole vehicle can be reduced is judged, and if the unsprung mass of the whole vehicle can be reduced, whether the second-order resonance peak value of the whole vehicle suspension corresponding to the adjusted tire pressure and the reduced unsprung mass of the whole vehicle can meet the set condition is judged.

Further, in the method and the device, if the second-order resonance peak value of the whole vehicle suspension after the unsprung mass of the whole vehicle is reduced still does not meet the set condition, the model of the tire is adjusted to be a smaller model, and whether the corresponding second-order resonance peak value of the whole vehicle suspension after the model of the tire is adjusted can meet the set condition is judged again.

Further, in the method and the device, if the second-order resonance peak value of the whole vehicle suspension after the tire pressure adjustment can meet the set condition, the corresponding tire rigidity after the tire pressure adjustment is calculated, and the tire model and the tire pressure are reselected according to the tire rigidity.

Further, in the method and the device, the setting condition further includes that the ratio of the second-order resonance peak value of the finished automobile suspension to the target value meets the setting range.

Further, in the method and the device, the target value is determined according to the corresponding relation between the smoothness of the existing whole vehicle and the benchmark vehicle and the second-order resonance peak value of the suspension of the whole vehicle.

Further, in the above method and apparatus, the step 1) is based on the formulaSelecting the model of the tire; in the formula, F₁For tire load-carrying capacity, F₂For the tire load, β is the set tire load rate limit.

Further, in the above method and apparatus, the step 1) is based on the formulaSelecting the tire pressure of the tire; in the formula, P_refFor indicating tyre pressure, Q_maxMarking the tyre with the corresponding maximum load-bearing capacity, Q, at the tyre pressure_rRequired tyre carrying capacity for real vehicles, P_rThe inflation pressure required by the real vehicle.

Drawings

FIG. 1 is a schematic view of a radial stiffness nonlinear curve of a tire in an embodiment of a vehicle tire matching method of the invention;

FIG. 2 is a GUI interface diagram of a tire model and tire pressure selection secondary development in an embodiment of a vehicle tire matching method of the invention;

FIG. 3 is a schematic diagram of a two-degree-of-freedom model of a vehicle in an embodiment of a whole vehicle tire matching method of the invention;

FIG. 4 is a schematic diagram of a simulation result for a vehicle two-degree-of-freedom model in the embodiment of the vehicle tire matching method of the invention;

FIG. 5 is a flow chart of the finished vehicle ride comfort simulation in the embodiment of the finished vehicle tire matching method of the present invention;

FIG. 6 is a flow chart of a vehicle tire matching method in an embodiment of the vehicle tire matching method of the invention.

Detailed Description

The embodiment of the matching method of the whole vehicle tire comprises the following steps:

the basic concept of the whole vehicle tire matching method of the embodiment is as follows: according to the type of the whole vehicle, initially screening the tire type and the tire pressure required by the whole vehicle from a large number of tire types as a primary screening result; then, establishing a whole vehicle ride comfort simulation model by combining the tire model and the tire pressure which are screened out primarily, simulating and outputting a whole vehicle suspension system transfer characteristic curve, and taking a second-order resonance peak value in the curve as a main evaluation index for tire matching; when the second-order resonance peak value in the curve can not meet the requirement, the tire pressure, the unsprung mass and the tire model are sequentially adjusted until the adjusted second-order resonance peak value meets the requirement, and then the finally adjusted tire is the tire matched with the whole vehicle and can meet the requirement on the smoothness of the whole vehicle.

The following describes the entire vehicle tire matching method of the present embodiment in detail:

1) the rigidity of the tire is positively correlated with the load bearing capacity of the tire, so the model number and the tire pressure of the tire are roughly selected from the matching degree of the load bearing capacity of the tire and the load of the tire.

For a vehicle type, the front and rear axle loads are determined, a proper tire is matched according to the axle load, the larger the bearing capacity of the tire is, the smaller the tire compression amount when the tire is fully loaded is, the larger the tire rigidity is, the worse the smoothness performance of the whole vehicle is, and therefore the following rules are set when the tire is selected initially:

in the formula, F₁For tire load-carrying capacity, F₂For the tire load, β is the set tire load rate limit. Where the determination of the beta value is obtained from a summary of the ride performance and tire tuning experience for a large number of products.

The tire bearing capacity can be determined by combining the formula (1), and the tire model required by the whole vehicle can be preliminarily screened out from a large number of tire models by taking the tire bearing capacity as a parameter.

Preliminary selection of tire pressure:

the static radial stiffness of the tire is mainly related to the tire structure (tread and side steel wire layer structure), the deformation of the tire and the tire pressure of the tire, and a radial stiffness nonlinear curve of the tire can be obtained through a loading test, as shown in fig. 1. As can be seen from FIG. 1, adjusting the tire pressure can change the vertical stiffness of the tire, and the lower the tire pressure, the lower the vertical stiffness of the tire, and the more beneficial the damping of the ride comfort unsprung vibration.

In order to conveniently select a proper tire model and tire pressure for the rigidity of the tire, test data are analyzed, a least square method is adopted to fit the test data under different tire pressures, a numerical relation between a vertical load and a deformation is obtained, and an empirical formula of the static radial nonlinear rigidity of the tire is established, wherein the empirical formula comprises the following specific steps:

F＝k₁*Δx+k₂*Δx² (2)

k₁＝a₁+b₁p (3)

k₂＝a₂+b₂p+c₂p² (4)

F＝(a₁+b₁p)*Δx+(a₂+b₂p+c₂p²)*Δx² (5)

in the formula, k₁、k₂Is the radial stiffness coefficient of the tire (strongly related to the tire pressure), p is the tire pressure, a₁、b₁、a₂、b₂、c₂And F is the magnitude of the load force borne by the tire, and deltax is the deformation amount.

According to the above formula, the tire pressure of the tire is reduced, the tire rigidity is reduced, the bearing capacity of the tire is reduced, and in order to prevent the tire from running under an overload condition, the bearing capacity after the tire pressure is reduced needs to be calculated, according to the regulations of technical organization engineering design manual (ETRTOEDI) of European tire rims published by the existing European tire rim technical organization: when the tire bearing capacity required by the real vehicle is smaller than the maximum bearing capacity corresponding to the nominal tire pressure of the tire, the inflation pressure required by the real vehicle can be calculated by referring to the following formula:

wherein, P_refFor indicating tyre pressure, Q_maxMarking the tyre with the corresponding maximum load-bearing capacity, Q, at the tyre pressure_rRequired tyre carrying capacity for real vehicles, P_rThe inflation pressure required by the real vehicle.

After the tire model is determined, the tire pressure marked by the tire can be determined, and the tire pressure marked by the tire can be determined by combining the formula (6)_rThe tire pressure of the corresponding tire required by the whole vehicle.

In order to improve the efficiency of primary tire screening, the tire model and tire pressure selection method of the embodiment is solidified in a Matlab secondary development mode, a basic vehicle model parameter database and a tire basic parameter database are established, and a secondary development GUI interface is shown in fig. 2 below.

2) After the tire model and the tire pressure are primarily selected, modeling simulation is carried out based on the primarily selected tire model and the tire pressure to obtain a corresponding suspension second-order resonance peak value

Fig. 3 shows a two-degree-of-freedom model of a vehicle, and fig. 4 shows a simulation result of the model, where a decrease in tire stiffness corresponds to a decrease in natural frequency of unsprung mass and an increase in damping ratio, and the simulation result shows that: the larger the radial rigidity of the tire is, the larger the radial vibration caused by uneven road surfaces is, and the larger the vibration transmitted to a vehicle body is, and the radial rigidity is the most important parameter influencing the radial vibration; moreover, the influence of the change of the tire rigidity on the first-order resonance peak value of the transfer characteristic of the suspension system is small, the second-order resonance peak value is mainly influenced, the tire rigidity is reduced, the curve of the second-order resonance peak value deviates leftwards, and the amplitude is obviously reduced. Therefore, tire stiffness is a major contributor to the second order resonance peak.

According to the existing products and benchmarking vehicles of companies, the unsprung vibration grade is divided into a high-end grade, a middle-end grade and a low-end grade, the second-order resonance peak value of the transfer characteristic of the whole vehicle suspension system corresponding to the three grades is determined, and the second-order resonance peak value can be used as an index for matching a proper tire with a subsequent new product.

The method comprises the following steps of establishing a whole vehicle ride comfort simulation model by combining the tire model and the tire pressure which are screened out for the first time, setting corresponding working conditions, simulation time, solving step length and output file step length, simulating and outputting a whole vehicle suspension system transfer characteristic curve, and taking a second-order resonance peak value in the curve as a main evaluation index for tire matching, wherein the specific flow is as shown in the following figure 5:

determining vehicle body characteristic parameters: determining basic parameters of the vehicle body characteristics required by simulation, such as the length, the width and the height of the whole vehicle, the wheelbase, the mass of the whole vehicle, the front and rear unsprung masses, the static radius of a tire, the rotational inertia of a vehicle body (roll, pitch and yaw), the product of the roll of the vehicle body around the mass center of the vehicle body and the inertia of the yaw, and the like.

Determining characteristic parameters of an axle and a suspension: the device comprises a spring compression and rebound nonlinear characteristic curve, a nonlinear characteristic curve of the damping force of the shock absorber changing along with the speed, left and right spans of the spring, left and right spans of the shock absorber, the height of the center of mass of an axle, the static radius of a wheel, the height of the center of mass of the axle, the mass of a front axle and a rear axle, the mass of a wheel assembly, the rotary inertia of the wheel assembly and the like.

Determining tire characteristic parameters: effective rolling radius of the tire, equivalent vertical rigidity at the tire balance position, tire model, wheel tread, maximum vertical force of the tire, width of the tire section and other parameters.

Setting pavement parameters: and setting the working conditions of a good road surface and a deceleration strip road surface which are commonly used for smoothness.

The road surface unevenness input module: and an A, B, C grade road surface with the common smoothness is established together with the road surface parameter module.

Setting vehicle speed parameters, namely controlling the running speed of the simulated vehicle.

The sensor setting module: and acquiring the measuring point signal as an original signal for subsequent processing.

And the data processing module: the time domain signal obtained by simulation can be converted into a frequency domain signal through Fourier change, and meanwhile, the amplitude-frequency characteristic of a section of frequency domain can be integrated to obtain the energy value of a section of frequency.

Ninthly will simulate the transmissionPerforming FRF frequency response function H on the output road surface power spectrum density curve and the road surface power spectrum density curve input by the road surface₁The estimation can obtain a transfer characteristic curve of the suspension system.

And carrying out simulation modeling according to the ride comfort simulation analysis flow of FIG. 5, outputting a suspension system transfer characteristic curve through a series of data processing modules, and obtaining a suspension second-order resonance peak value.

3) According to whether the second-order resonance peak value of the suspension meets the requirement or not, the matching of the whole vehicle tire is realized

The process of matching the whole vehicle tire according to whether the second-order resonance peak value of the suspension meets the requirement or not in the embodiment is shown in fig. 6.

If the suspension second-order resonance peak value analyzed by simulation is smaller than the target value, judging that the suspension second-order resonance peak value is established, indicating that the initially selected tire type and the tire pressure are matched with the whole vehicle type, and continuously performing other judgment on the suspension second-order resonance peak value downwards;

if the suspension second-order resonance peak value analyzed by simulation is larger than the target value, the judgment is not established, and the following step A is carried out;

a: adjusting the tire pressure according to the tire design specification and a formula 6, judging whether the second-order resonance peak value of the suspension obtained by simulation after the tire pressure is adjusted is lower than a target value, and if the second-order resonance peak value of the suspension obtained by simulation is lower than the target value due to the fact that proper tire pressure does not exist, entering the following step B; if the proper tire pressure can enable the second-order resonance peak value of the suspension to be lower than the target value, the following step C is carried out;

b: judging whether the unsprung mass can be reduced, if so, adjusting the unsprung mass, judging whether a second-order resonance peak value of the suspension obtained by simulation after the tire pressure is adjusted and the unsprung mass is adjusted meets a target, and if not, indicating that the tire model is selected to be larger, entering the following step D;

c: and (3) calculating the tire rigidity at the balance position according to the formula (5), reselecting the proper tire model and tire pressure according to the tire rigidity by using the formulas (1) and (6), and returning to the process to continue judging.

D: and reselecting the tire model, returning to the starting point and judging again.

Considering that the fact that the suspension second-order resonance peak value is larger than the target value means that the stiffness of the tire corresponding to the initially selected tire type and the tire pressure is larger than that of the whole vehicle type, the tire pressure is specifically adjusted to be reduced in step a, and the tire of the smaller type is reselected in step D. In the step a of this embodiment, the process of adjusting the tire pressure is not limited to one-time adjustment, and the unsprung mass reduction in the step B is considered only if the second-order resonance peak of the suspension obtained through simulation after multiple adjustments still cannot meet the requirement.

Considering the influence of the tire model on other attributes such as control stability and braking performance, the embodiment limits the ratio of the suspension second-order resonance peak value to the target value, if the ratio does not meet the requirement, the tire pressure is readjusted or the tire model is adjusted for matching, if the ratio meets the requirement, the tire model and the tire pressure are determined, and the matching of the tire is finished.

The tire matching method of the embodiment has the advantages that:

firstly, solving the problem of unsprung vibration caused by tire parameter selection by a specific quantification mode of a control index, wherein the method has higher accuracy compared with a method of matching tires by experience, and the influence of tire models on smoothness is considered from the perspective of forward design and development of tires;

finding out main influence factors of the unsprung vibration based on a test or simulation method, determining a proper range of the tire rigidity by controlling a mode of a second-order resonance peak value of the frequency response of a suspension system, and selecting a proper tire model and tire pressure according to the tire rigidity;

considering the influence factors of the tire pressure and the tire deformation on the tire rigidity, finding out an empirical formula according to experimental data by adopting a polynomial fitting method, quickly calculating the tire rigidity of different tire deformation and different tire pressure, and improving the tire matching efficiency;

and fourthly, considering that the tire is possible to be a main vibration source due to the problems of assembly, non-uniformity of the tire and the like, and providing a method for detecting whether the uniformity of the tire, the imbalance degree of the assembly of the tire and a rim and the imbalance degree of the rim meet the requirements or not.

In this embodiment, the initial selection of the tire model and the tire pressure is realized according to the formulas (1) and (6), and as another embodiment, the initial selection of the tire model and the tire pressure may also be realized according to experience.

In this embodiment, the suspension second-order resonance peak is obtained by performing simulation on the entire vehicle, and as another embodiment, the suspension second-order resonance peak may also be obtained by performing real experiments on the entire vehicle.

In the embodiment, the influence of the tire model on other attributes such as steering stability and braking performance is also considered, so that the whole vehicle tire matching method further comprises the step of judging whether the ratio of the second-order resonance peak value of the suspension to the target value meets the requirement, and as other implementation modes, the step of judging whether the ratio meets the requirement can be omitted according to the requirement.

All steps in the whole vehicle matching method can be realized by a computer, and can also be realized by a mode of combining the computer and manpower.

The embodiment of the whole vehicle tire matching device comprises:

the apparatus proposed in this embodiment includes a processor and a memory, where a computer program operable on the processor is stored in the memory, and the processor implements the method of the above method embodiment when executing the computer program.

That is, the method in the above method embodiment should be understood that the flow of the entire vehicle matching method can be implemented by computer program instructions. These computer program instructions may be provided to a processor (e.g., a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus), such that the instructions, which execute via the processor, create means for implementing the functions specified in the method flow.

The processor referred to in this embodiment refers to a processing device such as a microprocessor MCU or a programmable logic device FPGA;

the memory referred to in this embodiment includes a physical device for storing information, and generally, information is digitized and then stored in a medium using an electric, magnetic, optical, or the like. For example: various memories for storing information by using an electric energy mode, such as RAM, ROM and the like; various memories for storing information by magnetic energy, such as hard disk, floppy disk, magnetic tape, magnetic core memory, bubble memory, and U disk; various types of memory, CD or DVD, that store information optically. Of course, there are other ways of memory, such as quantum memory, graphene memory, and so forth.

The apparatus comprising the memory, the processor and the computer program is realized by the processor executing corresponding program instructions in the computer, and the processor can be loaded with various operating systems, such as windows operating system, linux system, android, iOS system, and the like.