CN114715160A

CN114715160A - Slip ratio calculation method, slip ratio calculation device, computer equipment and storage medium

Info

Publication number: CN114715160A
Application number: CN202210445294.3A
Authority: CN
Inventors: 万里恩; 刘明明; 张军; 郭冬妮; 陈宇超; 乔艳辉; 王天璐; 田博; 高枫; 王玉博
Original assignee: FAW Jiefang Automotive Co Ltd
Current assignee: FAW Jiefang Automotive Co Ltd
Priority date: 2022-04-26
Filing date: 2022-04-26
Publication date: 2022-07-08

Abstract

The application relates to a slip ratio calculation method, a slip ratio calculation device, a computer device, a storage medium and a computer program product. The method comprises the following steps: acquiring current wheel speeds of all wheels of the vehicle at the current moment; all wheels comprise a front left wheel, a front right wheel, a rear left wheel and a rear right wheel; determining the current reference speed of the vehicle at the current moment according to the current wheel speeds of all wheels; determining the current slip rate of each wheel at the current moment according to the current wheel speed of each wheel and the current reference vehicle speed; filtering the current slip rate of the rear left wheel according to the slip rate of the front left wheel at the previous moment and the slip rate of the rear left wheel at the previous moment to obtain the real slip rate of the rear left wheel; and filtering the current slip rate of the rear right wheel according to the slip rate of the front right wheel at the previous moment and the slip rate of the rear right wheel at the previous moment to obtain the real slip rate of the rear right wheel. Therefore, the accuracy of the real slip ratio of the rear left wheel and the rear right wheel is improved, and the braking efficiency of the ABS is further improved.

Description

Slip ratio calculation method, slip ratio calculation device, computer equipment and storage medium

Technical Field

The present application relates to the field of vehicle braking technologies, and in particular, to a slip ratio calculation method, apparatus, computer device, storage medium, and computer program product.

Background

An ABS (antilock brake system) plays an important role in a modern car safety system, and a road surface identification algorithm in the ABS relates to calibration and selection of ABS control parameters, and whether road surface identification is accurate or not directly determines the performance effect of the ABS, so the road surface identification algorithm is one of the cores of ABS control software.

In the related art, the ABS generally determines a current road surface by a slip ratio, and specifically, calculates a slip ratio of a vehicle by a vehicle speed and a wheel speed. And for the off-road, usually, the road surface is uneven, the unevenness of the road surface causes great wheel speed fluctuation of the vehicle, the slip rate of the rear wheel calculated through the vehicle speed and the wheel speed is distorted, the braking efficiency of the ABS is influenced, and the rear wheel of the vehicle generates drift or sideslip.

Disclosure of Invention

Based on this, it is necessary to provide a slip ratio calculation method, apparatus, computer device, computer readable storage medium and computer program product capable of making the obtained real slip ratio of the rear left wheel and the real slip ratio of the rear right wheel more approximate to the slip ratio during actual running of the rear wheels, in view of the above technical problems.

In a first aspect, the present application provides a slip ratio calculation method. The method comprises the following steps:

acquiring current wheel speeds of all wheels of the vehicle at the current moment; all wheels comprise a front left wheel, a front right wheel, a rear left wheel and a rear right wheel;

determining the current reference speed of the vehicle at the current moment according to the current wheel speeds of all wheels;

determining the current slip rate of each wheel at the current moment according to the current wheel speed of each wheel and the current reference vehicle speed;

filtering the current slip rate of the rear left wheel according to the slip rate of the front left wheel at the previous moment and the slip rate of the rear left wheel at the previous moment to obtain the real slip rate of the rear left wheel;

and filtering the current slip rate of the rear right wheel according to the slip rate of the front right wheel at the previous moment and the slip rate of the rear right wheel at the previous moment to obtain the real slip rate of the rear right wheel.

In one embodiment, determining the current reference vehicle speed of the vehicle at the current time based on the current wheel speeds of all wheels comprises:

if the current wheel speed which is larger than the reference vehicle speed at the last moment exists in the current wheel speeds of all the wheels, taking the maximum current wheel speed in the current wheel speeds of all the wheels as the current reference vehicle speed; if the current wheel speed which is larger than the reference vehicle speed at the last moment does not exist in the current wheel speeds of all the wheels and the current moment is the initial braking moment, taking the minimum current wheel speed in the current wheel speeds of all the wheels as the initial reference vehicle speed, and determining the current reference vehicle speed according to the initial reference vehicle speed, the vehicle body deceleration and the first time difference between the current moment and the last moment;

if the current wheel speed which is larger than the reference vehicle speed at the last moment does not exist in the current wheel speeds of all the wheels and the current moment is not the initial braking moment, obtaining the wheels with the current wheel deceleration equal to the preset threshold value from all the wheels, taking the current wheel speed of the wheels with the current wheel deceleration equal to the preset threshold value as the initial reference vehicle speed, and determining the current reference vehicle speed according to the initial reference vehicle speed, the vehicle body deceleration and the first time difference between the current moment and the last moment;

if the current wheel speed which is larger than the reference vehicle speed at the last moment does not exist in the current wheel speeds of all the wheels, the current moment is not the initial braking moment, and the wheels of which the current wheel deceleration is equal to the preset threshold value are not obtained in all the wheels, taking the reference vehicle speed at the last moment as the initial reference vehicle speed, and determining the current reference vehicle speed according to the initial reference vehicle speed, the vehicle body deceleration and the first time difference between the current moment and the last moment.

In one embodiment, determining the current reference vehicle speed based on the initial reference vehicle speed, the vehicle body deceleration, and a first time difference between the current time and a previous time includes:

and acquiring a first product between the deceleration of the vehicle body and the first time difference, acquiring a first difference value between the initial reference vehicle speed and the first product, and taking the first difference value as the current reference vehicle speed.

In one embodiment, the determination of the deceleration of the vehicle body includes:

judging whether the braking process corresponding to the current moment belongs to first braking, if so, obtaining the deceleration value of the vehicle body to be 0.6g, if not, obtaining the wheel speed corresponding to the preset moment of all the wheels in the last braking process, and determining the deceleration of the vehicle body according to the filter coefficient, the vehicle body deceleration of the last braking process, the maximum wheel speed in the wheel speeds corresponding to the preset moment of all the wheels in the last braking process, and a second time difference between the preset moment and the last moment of the preset moment.

In one embodiment, determining the deceleration of the vehicle body according to the filter coefficient, the deceleration of the vehicle body in the last braking process, the maximum wheel speed of the wheel speeds of all the wheels corresponding to the preset time in the last braking process, and the second time difference between the preset time and the last time of the preset time comprises:

calculating a second difference value between the 1 and the filter coefficient, and acquiring a second product between the second difference value and the vehicle body deceleration in the last braking process;

acquiring a third difference value between the maximum wheel speed of the wheel speeds corresponding to the preset time in the last braking process of all the wheels and the maximum wheel speed of the wheel speeds corresponding to the last time of the preset time in the last braking process of all the wheels; acquiring a first ratio between the third difference and the second time difference; obtaining a third product between the first ratio and the filter coefficient;

and acquiring a sum value between the second product and the third product, and taking the sum value as the vehicle body deceleration.

In one embodiment, the filtering the current slip ratio of the rear left wheel according to the slip ratio of the front left wheel at the previous moment and the slip ratio of the rear left wheel at the previous moment to obtain the real slip ratio of the rear left wheel includes:

acquiring an absolute value of a fourth difference value between the slip ratio of the front left wheel at the previous moment and the slip ratio of the rear left wheel at the previous moment;

acquiring a fifth difference value between the current slip ratio of the rear left wheel and the absolute value of the fourth difference value;

and taking the fifth difference value as the real slip ratio of the rear left wheel.

In a second aspect, the present application further provides a slip ratio calculation apparatus. The device comprises:

the device comprises an acquisition module, a control module and a control module, wherein the acquisition module is used for acquiring the current wheel speeds of all wheels of a vehicle at the current moment; all wheels comprise a front left wheel, a front right wheel, a rear left wheel and a rear right wheel;

the first determining module is used for determining the current reference speed of the vehicle at the current moment according to the current wheel speeds of all wheels;

the second determining module is used for determining the current slip rate of each wheel at the current moment according to the current wheel speed of each wheel and the current reference vehicle speed;

the third determining module is used for filtering the current slip rate of the rear left wheel according to the slip rate of the front left wheel at the previous moment and the slip rate of the rear left wheel at the previous moment to obtain the real slip rate of the rear left wheel;

and the fourth determining module is used for filtering the current slip rate of the rear right wheel according to the slip rate of the front right wheel at the previous moment and the slip rate of the rear right wheel at the previous moment to obtain the real slip rate of the rear right wheel.

In a third aspect, the present application also provides a computer device. The computer device comprises a memory storing a computer program and a processor implementing the following steps when executing the computer program:

acquiring current wheel speeds of all wheels of a vehicle at the current moment; all wheels comprise a front left wheel, a front right wheel, a rear left wheel and a rear right wheel;

In a fourth aspect, the present application further provides a computer-readable storage medium. The computer-readable storage medium having stored thereon a computer program which, when executed by a processor, performs the steps of:

In a fifth aspect, the present application further provides a computer program product. The computer program product comprising a computer program which when executed by a processor performs the steps of:

The slip ratio calculating method, the slip ratio calculating device, the computer equipment, the storage medium and the computer program product are characterized in that the current wheel speeds of all wheels of the vehicle at the current moment are obtained; all wheels comprise a front left wheel, a front right wheel, a rear left wheel and a rear right wheel; determining the current reference speed of the vehicle at the current moment according to the current wheel speeds of all wheels; determining the current slip rate of each wheel at the current moment according to the current wheel speed of each wheel and the current reference vehicle speed; filtering the current slip rate of the rear left wheel according to the slip rate of the front left wheel at the previous moment and the slip rate of the rear left wheel at the previous moment to obtain the real slip rate of the rear left wheel; and filtering the current slip rate of the rear right wheel according to the slip rate of the front right wheel at the previous moment and the slip rate of the rear right wheel at the previous moment to obtain the real slip rate of the rear right wheel. The current slip rate of the rear left wheel is not directly used as the real slip rate of the rear left wheel and the current slip rate of the rear right wheel is used as the real slip rate of the rear right wheel, but the current slip rate of the rear left wheel is filtered according to the slip rate of the front left wheel at the previous moment and the slip rate of the rear left wheel at the previous moment, so that the real slip rate of the rear left wheel is obtained; according to the slip rate of the front right wheel at the previous moment and the slip rate of the rear right wheel at the previous moment, filtering the current slip rate of the rear right wheel to obtain the real slip rate of the rear right wheel, so that the obtained real slip rate of the rear left wheel and the real slip rate of the rear right wheel are closer to the slip rate of the rear wheel in the actual driving process, the accuracy of the real slip rate of the rear left wheel and the real slip rate of the rear right wheel is improved, the braking efficiency of the ABS is further improved, the phenomenon that the wheel speed of the vehicle is fluctuated greatly due to uneven pits on a cross-country road surface, the slip rate of the rear wheel obtained by calculating the vehicle speed and the wheel speed is distorted, the braking efficiency of the ABS is influenced, and the rear wheel of the vehicle is subjected to tail flicking or sideslip.

Drawings

FIG. 1 is a schematic flow chart of a slip ratio calculation method in one embodiment;

FIG. 2 is a block diagram showing the structure of a slip ratio calculating means in one embodiment;

FIG. 3 is a diagram illustrating an internal structure of a computer device according to an embodiment.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

It will be understood that, as used herein, the terms "first," "second," and the like may be used herein to describe various terms, but these terms are not limited by these terms unless otherwise specified. These terms are only used to distinguish one term from another. For example, the first time difference and the second time difference may be the same or different without departing from the scope of the present application.

In view of the problems in the related art, embodiments of the present invention provide a slip ratio calculating method, which may be applied to a server, a terminal, or a system including the terminal and the server, and is implemented by interaction between the terminal and the server. The server may be implemented by an independent server or a server cluster composed of a plurality of servers. The terminal can be but not limited to various personal computers, notebook computers, smart phones, tablet computers, internet of things equipment and portable wearable equipment, and the internet of things equipment can be intelligent sound boxes, intelligent televisions, intelligent air conditioners, intelligent vehicle-mounted equipment and the like. The portable wearable device can be a smart watch, a smart bracelet, a head-mounted device, and the like. It should be noted that, the numbers of "a plurality" and the like mentioned in the embodiments of the present application each refer to a number of "at least two", for example, "a plurality" refers to "at least two".

Before describing the specific implementation of the embodiment of the present invention, a description will be given of a main application scenario of the embodiment of the present invention. The embodiment of the invention provides a slip ratio calculation method which is mainly applied to braking of a vehicle in the running process of a cross-country road surface, the slip ratio of the vehicle in the braking process is obtained in real time, the slip ratio is fed back to an ABS (anti-lock braking system), and the ABS controls the scene of the braking process of the vehicle based on the slip ratio obtained in real time. The method mainly comprises the steps that when the vehicle brakes, the current wheel speeds of all wheels of the vehicle in the braking process are obtained in real time; determining the current reference speed of the vehicle according to the current wheel speeds of all wheels; determining the current slip rate of each wheel according to the current wheel speed of each wheel and the current reference vehicle speed; filtering the current slip rate of the rear left wheel according to the slip rate of the front left wheel at the previous moment and the slip rate of the rear left wheel at the previous moment to obtain the real slip rate of the rear left wheel; and filtering the current slip rate of the rear right wheel according to the slip rate of the front right wheel at the previous moment and the slip rate of the rear right wheel at the previous moment to obtain the real slip rate of the rear right wheel. The slip rate of the rear wheel obtained by calculating the speed and the wheel speed is not directly used as the real slip rate of the rear wheel, but the slip rate of the rear wheel is filtered according to the slip rate of the front wheel, and the filtered slip rate is used as the real slip rate of the rear wheel, so that the real slip rate of the rear wheel obtained by calculation is closer to the slip rate of the rear wheel in the actual driving process, and the braking efficiency of the ABS is improved.

In one embodiment, as shown in fig. 1, a slip ratio calculation method is provided, and this embodiment is illustrated by applying the method to a server, and the method includes the following steps:

102. acquiring current wheel speeds of all wheels of a vehicle at the current moment; all wheels include a front left wheel, a front right wheel, a rear left wheel and a rear right wheel.

Specifically, a wheel speed sensor may be provided on each wheel of the vehicle, and the current wheel speeds of all the wheels at the current time are acquired based on the wheel speed sensors.

It should be noted that, when the vehicle is not braked, the slip ratios of all the wheels are 0, and therefore, when the vehicle is not braked, the slip ratio of the vehicle does not need to be calculated. Based on this, it can be understood that the current time is the time during which the vehicle is braking.

104. And determining the current reference vehicle speed of the vehicle at the current moment according to the current wheel speeds of all wheels.

Specifically, the largest current wheel speed among the current wheel speeds of all the wheels may be acquired, and then the largest current wheel speed may be taken as the current reference vehicle speed. Wherein, the process of obtaining the largest current wheel speed among the current wheel speeds of all wheels may be represented by the following formula (1):

maxω＝max(max(ω_fl，ω_fr)，max(ω_rl，ω_rr))； (1)

it should be noted that max ω represents the maximum current wheel speed among the current wheel speeds of all wheels, ω_flRepresenting the current wheel speed, omega, of the front left wheel_frCurrent wheel speed, ω, of the front right wheel_rlRepresenting the current wheel speed, ω, of the rear left wheel_rrRepresenting the current wheel speed of the rear right wheel and max representing the maximum value.

106. And determining the current slip rate of each wheel at the current moment according to the current wheel speed of each wheel and the current reference vehicle speed.

Specifically, for any one of all wheels, a sixth difference value between the current reference vehicle speed and the current wheel speed of any one wheel is obtained; acquiring a second ratio between the sixth difference and the current reference vehicle speed; the second ratio is taken as the current slip ratio of any one wheel.

The specific process of obtaining the current slip rate of each wheel at the current time may refer to the following formula (2):

λ_{x_c}＝(Vref-ω)/Vref； (2)

in this specification, λ_{x_c}And Vref is the current reference vehicle speed, and omega is the current wheel speed of any wheel.

108. And filtering the current slip rate of the rear left wheel according to the slip rate of the front left wheel at the previous moment and the slip rate of the rear left wheel at the previous moment to obtain the real slip rate of the rear left wheel.

Specifically, a seventh difference value between the slip ratio of the front left wheel at the last moment and the slip ratio of the rear left wheel at the last moment is obtained, and based on the seventh difference value, the current slip ratio of the rear left wheel is filtered to obtain the real slip ratio of the rear left wheel.

110. And filtering the current slip rate of the rear right wheel according to the slip rate of the front right wheel at the previous moment and the slip rate of the rear right wheel at the previous moment to obtain the real slip rate of the rear right wheel.

Specifically, an eighth difference value between the slip ratio of the front right wheel at the previous moment and the slip ratio of the rear right wheel at the previous moment is obtained, and based on the eighth difference value, the current slip ratio of the rear right wheel is filtered to obtain the real slip ratio of the rear right wheel.

In the slip ratio calculation method, the current wheel speeds of all wheels of the vehicle at the current moment are obtained; all wheels comprise a front left wheel, a front right wheel, a rear left wheel and a rear right wheel; determining the current reference speed of the vehicle at the current moment according to the current wheel speeds of all wheels; determining the current slip rate of each wheel at the current moment according to the current wheel speed of each wheel and the current reference vehicle speed; filtering the current slip rate of the rear left wheel according to the slip rate of the front left wheel at the previous moment and the slip rate of the rear left wheel at the previous moment to obtain the real slip rate of the rear left wheel; and filtering the current slip rate of the rear right wheel according to the slip rate of the front right wheel at the previous moment and the slip rate of the rear right wheel at the previous moment to obtain the real slip rate of the rear right wheel. The current slip rate of the rear left wheel is not directly used as the real slip rate of the rear left wheel and the current slip rate of the rear right wheel is used as the real slip rate of the rear right wheel, but the current slip rate of the rear left wheel is filtered according to the slip rate of the front left wheel at the last moment and the slip rate of the rear left wheel at the last moment, so that the real slip rate of the rear left wheel is obtained; according to the slip rate of the front right wheel at the previous moment and the slip rate of the rear right wheel at the previous moment, filtering the current slip rate of the rear right wheel to obtain the real slip rate of the rear right wheel, so that the obtained real slip rate of the rear left wheel and the real slip rate of the rear right wheel are closer to the slip rate of the rear wheel in the actual driving process, the accuracy of the real slip rate of the rear left wheel and the real slip rate of the rear right wheel is improved, the braking efficiency of the ABS is further improved, the phenomenon that the wheel speed of the vehicle is fluctuated greatly due to uneven pits on a cross-country road surface, the slip rate of the rear wheel obtained by calculating the vehicle speed and the wheel speed is distorted, the braking efficiency of the ABS is influenced, and the rear wheel of the vehicle is subjected to tail flicking or sideslip.

In one embodiment, determining a current reference vehicle speed of the vehicle at a current time based on current wheel speeds of all wheels comprises:

if the current wheel speed which is greater than the reference vehicle speed at the last moment exists in the current wheel speeds of all the wheels, taking the maximum current wheel speed in the current wheel speeds of all the wheels as the current reference vehicle speed; if the current wheel speed which is larger than the reference vehicle speed at the last moment does not exist in the current wheel speeds of all the wheels and the current moment is the initial braking moment, the minimum current wheel speed in the current wheel speeds of all the wheels is used as the initial reference vehicle speed, and the current reference vehicle speed is determined according to the initial reference vehicle speed, the vehicle body deceleration and the first time difference between the current moment and the last moment.

It should be noted that, the determination process of the reference vehicle speed at the previous time may refer to the determination process of the current reference vehicle speed, and therefore, the details are not described here.

If the current wheel speed which is larger than the reference vehicle speed at the last moment does not exist in the current wheel speeds of all the wheels and the current moment is not the initial braking moment, obtaining the wheels with the current wheel deceleration equal to the preset threshold value from all the wheels, taking the current wheel speed of the wheels with the current wheel deceleration equal to the preset threshold value as the initial reference vehicle speed, and determining the current reference vehicle speed according to the initial reference vehicle speed, the vehicle body deceleration and the first time difference between the current moment and the last moment.

If the current wheel speed which is larger than the reference vehicle speed at the last moment does not exist in the current wheel speeds of all the wheels, the current moment is not the initial braking moment, and the wheels with the current wheel deceleration equal to the preset threshold value are not obtained in all the wheels, the reference vehicle speed at the last moment is used as the initial reference vehicle speed, and the current reference vehicle speed is determined according to the initial reference vehicle speed, the vehicle body deceleration and the first time difference between the current moment and the last moment.

In this embodiment, if the current wheel speeds of all the wheels are greater than the reference vehicle speed at the previous moment, the largest current wheel speed of the current wheel speeds of all the wheels is used as the current reference vehicle speed; if the current wheel speed which is larger than the reference vehicle speed at the last moment does not exist in the current wheel speeds of all the wheels and the current moment is the initial braking moment, taking the minimum current wheel speed in the current wheel speeds of all the wheels as the initial reference vehicle speed, and determining the current reference vehicle speed according to the initial reference vehicle speed, the vehicle body deceleration and the first time difference between the current moment and the last moment; if the current wheel speed which is larger than the reference vehicle speed at the last moment does not exist in the current wheel speeds of all the wheels and the current moment is not the initial braking moment, obtaining the wheels with the current wheel deceleration equal to the preset threshold value from all the wheels, taking the current wheel speed of the wheels with the current wheel deceleration equal to the preset threshold value as the initial reference vehicle speed, and determining the current reference vehicle speed according to the initial reference vehicle speed, the vehicle body deceleration and a first time difference between the current moment and the last moment; if the current wheel speed which is larger than the reference vehicle speed at the last moment does not exist in the current wheel speeds of all the wheels, the current moment is not the initial braking moment, and the wheels with the current wheel deceleration equal to the preset threshold value are not obtained in all the wheels, the reference vehicle speed at the last moment is used as the initial reference vehicle speed, and the current reference vehicle speed is determined according to the initial reference vehicle speed, the vehicle body deceleration and the first time difference between the current moment and the last moment. The current reference vehicle speed is determined based on the actual running condition of the wheels of the vehicle in the braking process, so that the determined current reference vehicle speed is closer to the actual vehicle speed of the vehicle, the accuracy of the determined current slip ratio of each wheel at the current moment is improved, and the accuracy of the real slip ratios of the rear left wheel and the rear right wheel is improved.

and acquiring a first product between the vehicle body deceleration and the first time difference, acquiring a first difference between the initial reference vehicle speed and the first product, and taking the first difference as the current reference vehicle speed.

Specifically, the determination process of the current reference vehicle speed may refer to the following equation (3):

Vref＝Vrefo-a_ref*Δt； (3)

it should be noted that Vref represents the current reference vehicle speed, Vrefo represents the initial reference vehicle speed, a_refRepresents the vehicle body deceleration, and Δ t represents a first time difference between the present time and the previous time.

In one embodiment, the determination process of the vehicle body deceleration includes:

judging whether the braking process corresponding to the current moment belongs to first braking, if so, obtaining the deceleration value of the vehicle body to be 0.6g, otherwise, obtaining the wheel speed corresponding to the preset moment of all the wheels in the last braking process, and determining the deceleration of the vehicle body according to the filter coefficient, the vehicle body deceleration of the last braking process, the maximum wheel speed in the wheel speeds corresponding to the preset moments of all the wheels in the last braking process, the maximum wheel speed in the wheel speeds corresponding to the last moment of the preset moments of all the wheels in the last braking process and a second time difference between the preset moment and the last moment of the preset moments.

The preset time may be an end time of the braking process.

Note that the vehicle body deceleration at the initial braking takes 0.6g because the road surface information obtained at the first duty cycle of the ABS is limited, and therefore, the vehicle body deceleration is set at a high road surface.

The value range of the filter coefficient is 0 to 1, and it should be noted that the value range of the filter coefficient is determined according to the road result and considering factors such as the identification response speed and the anti-interference performance.

In one embodiment, determining the deceleration of the vehicle body based on the filter coefficient, the deceleration of the vehicle body of the last braking process, the maximum wheel speed among the wheel speeds of all the wheels corresponding to the preset time in the last braking process, and the second time difference between the preset time and the last time of the preset time comprises:

calculating a second difference value between the 1 and the filter coefficient, and acquiring a second product between the second difference value and the vehicle body deceleration in the last braking process; acquiring a third difference value between the maximum wheel speed of the wheel speeds of all the wheels corresponding to the preset time in the last braking process and the maximum wheel speed of the wheel speeds of all the wheels corresponding to the last time in the last braking process; acquiring a first ratio between the third difference and the second time difference; obtaining a third product between the first ratio and the filter coefficient; and acquiring a sum value between the second product and the third product, and taking the sum value as the vehicle body deceleration.

Specifically, the determination process of the vehicle body deceleration may refer to the following formula (4):

in addition, a is_refRepresenting vehicle body deceleration, k₁Represents the filter coefficient, a_ref-1Vehicle body deceleration, V, representing last braking process_wnRepresenting the maximum wheel speed, V, of the wheel speeds of all the wheels at the preset moment of the last braking process_wn-1Representing the maximum wheel speed, t, of the wheel speeds of all the wheels at the last instant of the preset instant in the last braking process_nRepresents a predetermined time, t_n-1Representing the time immediately preceding the preset time.

acquiring an absolute value of a fourth difference value between the slip ratio of the front left wheel at the previous moment and the slip ratio of the rear left wheel at the previous moment; acquiring a fifth difference value between the current slip ratio of the rear left wheel and the absolute value of the fourth difference value; and taking the fifth difference value as the real slip ratio of the rear left wheel.

The determination process of the slip ratio of the front left wheel at the previous moment and the determination process of the slip ratio of the rear left wheel at the previous moment can both refer to the determination process of the current slip ratio of each wheel, and details are not repeated here.

Specifically, the determination process of the true slip ratio of the rear left wheel may refer to the following formula (5):

λ_{rl_r}＝λ_{rl_c}-Δλ_rl； (5)

in addition, λ is_{rl_r}Representing the true slip ratio, λ, of the rear left wheel_{rl_c}Representing the current slip ratio, Δ λ, of the rear left wheel_rlAnd represents an absolute value of a fourth difference between the slip ratio of the front left wheel at the previous time and the slip ratio of the rear left wheel at the previous time. Wherein, Δ λ_rlAnd also represents the road surface unevenness of the front left wheel at the previous moment. It can be understood that, the rear left wheel runs along the track of the front left wheel in the running process of the vehicle, so that the current slip rate of the rear left wheel can be filtered through the road surface unevenness of the front left wheel at the last moment, the real slip rate of the rear left wheel is obtained, the real slip rate of the rear left wheel is closer to the slip rate of the rear left wheel in the actual running process, and the braking efficiency of the ABS is further improved.

In the embodiment, the absolute value of a fourth difference value between the slip ratio of the front left wheel at the last moment and the slip ratio of the rear left wheel at the last moment is obtained; acquiring a fifth difference value between the current slip ratio of the rear left wheel and the absolute value of the fourth difference value; and taking the fifth difference as the real slip ratio of the rear left wheel. The current slip rate of the rear left wheel is filtered through the road surface unevenness of the front left wheel at the previous moment, so that the real slip rate of the rear left wheel is obtained, the real slip rate of the rear left wheel is closer to the slip rate of the rear left wheel in the actual driving process, and the braking efficiency of the ABS is improved.

In one embodiment, the filtering the current slip ratio of the rear right wheel according to the slip ratio of the front right wheel at the previous moment and the slip ratio of the rear right wheel at the previous moment to obtain the real slip ratio of the rear right wheel includes:

acquiring an absolute value of a ninth difference value between the slip ratio of the front right wheel at the previous moment and the slip ratio of the rear right wheel at the previous moment; acquiring a tenth difference value between the current slip ratio of the rear right wheel and the absolute value of the ninth difference value; and taking the tenth difference as the real slip ratio of the rear right wheel.

The determination process of the slip ratio of the front right wheel at the previous moment and the determination process of the slip ratio of the rear right wheel at the previous moment can both refer to the determination process of the current slip ratio of each wheel, and details are not repeated here.

Specifically, the determination process of the true slip ratio of the rear right wheel may refer to the following formula (6):

λ_{rr_r}＝λ_{rr_c}-Δλ_rr； (6)

in addition, λ is_{rr_r}Representing the real slip ratio, λ, of the rear right wheel_{rr_c}Representing the current slip ratio, Δ λ, of the rear right wheel_rrRepresents an absolute value of a ninth difference between the slip ratio of the front right wheel at the previous time and the slip ratio of the rear right wheel at the previous time. Wherein, Δ λ_rrAnd also represents the road surface unevenness of the front right wheel at the previous moment. It can be understood that, the rear right wheel runs along the track of the front right wheel in the running process of the vehicle, so that the current slip rate of the rear right wheel can be filtered through the road surface unevenness of the front right wheel at the last moment, the real slip rate of the rear right wheel is obtained, the real slip rate of the rear right wheel is closer to the slip rate of the rear right wheel in the actual running process, and the braking efficiency of the ABS is further improved.

In the embodiment, the current slip rate of the rear right wheel is filtered through the road surface unevenness of the front right wheel at the previous moment, so that the real slip rate of the rear right wheel is obtained, the real slip rate of the rear right wheel is closer to the slip rate of the rear right wheel in the actual driving process, and the braking efficiency of the ABS is further improved.

acquiring an absolute value of a fourth difference between the slip ratio of the front left wheel at the previous moment and the slip ratio of the rear left wheel at the previous moment; calculating a fourth product between the absolute value of the fourth difference and the scaling factor; calculating an eleventh difference between the current slip ratio of the rear left wheel and the fourth product; and taking the eleventh difference value as the real slip ratio of the rear left wheel.

Specifically, the determination process of the true slip ratio of the rear left wheel may refer to the following formula (7):

λ_{rl_r}＝λ_{rl_c}-k₂Δλ_rl； (7)

in addition, k is₂For the explanation of other parameters in equation (7) representing the scaling factor, refer to equation (5), which is not described herein again.

acquiring an absolute value of a ninth difference value between the slip ratio of the front right wheel at the previous moment and the slip ratio of the rear right wheel at the previous moment; calculating a fifth product between the absolute value of the ninth difference and the scaling factor; calculating a twelfth difference between the current slip ratio of the rear right wheel and the fifth product; and taking the twelfth difference value as the real slip ratio of the rear right wheel.

Specifically, the determination process of the true slip ratio of the rear right wheel may refer to the following formula (8):

λ_{rr_r}＝λ_{rr_c}-k₂Δλ_rr； (8)

it should be noted that, for the explanation of each parameter in the formula (8), reference may be made to the formula (6) and the formula (7).

acquiring the time quantity between the initial braking time and the current time;

the method comprises the steps that the slip rate of a front left wheel at each moment between an initial braking moment and a current moment and the slip rate of a rear left wheel at each moment between the initial braking moment and the current moment are obtained;

acquiring an absolute value of a thirteenth difference value between the slip ratio of the front left wheel at each moment between the initial braking moment and the current moment and the slip ratio of the rear left wheel at each moment between the initial braking moment and the current moment; summing the absolute value of a thirteenth difference value corresponding to each moment between the initial braking moment and the current moment to obtain a summation result; acquiring a third ratio between the summation result and the time quantity; calculating a sixth product between the third ratio and the scaling factor;

calculating a fourteenth difference between the current slip ratio of the rear left wheel and the sixth product; and taking the fourteenth difference value as the real slip ratio of the rear left wheel.

Specifically, the determination process of the true slip ratio of the rear left wheel may refer to the following formula (9):

λ_{rl_r}＝λ_{rl_c}-k₂*[(Δλ₁+Δλ₂+Δλ₃+……Δλ_n)/n]； (9)

in addition, (Δ λ)₁+Δλ₂+Δλ₃+……Δλ_n) Representing the summation result, n represents the number of time instants between the initial braking time instant and the current time instant, and the explanation of other parameters in the formula (9) can refer to the formula (7), which is not described herein again.

It should be noted that, the determination process of the actual slip ratio of the rear right wheel may refer to the determination process of the actual slip ratio of the rear left wheel, and is not described herein again.

It should be understood that, although the steps in the flowcharts related to the embodiments described above are shown in sequence as indicated by the arrows, the steps are not necessarily performed in sequence as indicated by the arrows. The steps are not limited to being performed in the exact order illustrated and, unless explicitly stated herein, may be performed in other orders. Moreover, at least a part of the steps in the flowcharts related to the embodiments described above may include multiple steps or multiple stages, which are not necessarily performed at the same time, but may be performed at different times, and the execution order of the steps or stages is not necessarily sequential, but may be performed alternately or alternately with other steps or at least a part of the steps or stages in other steps.

Based on the same inventive concept, the embodiment of the present application further provides a slip ratio calculation apparatus for implementing the slip ratio calculation method. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the method, so the specific limitations in one or more embodiments of the slip ratio calculation device provided below can be referred to the limitations on the slip ratio calculation method in the above, and details are not repeated here.

In one embodiment, as shown in fig. 2, there is provided a slip ratio calculation apparatus including: an acquisition module 202, a first determination module 204, a second determination module 206, a third determination module 208, and a fourth determination module 210, wherein:

an obtaining module 202, configured to obtain current wheel speeds of all wheels of a vehicle at a current time; all wheels comprise a front left wheel, a front right wheel, a rear left wheel and a rear right wheel;

the first determination module 204 is configured to determine a current reference vehicle speed of the vehicle at a current moment according to current wheel speeds of all wheels;

a second determining module 206, configured to determine a current slip rate of each wheel at a current time according to a current wheel speed of each wheel and a current reference vehicle speed;

a third determining module 208, configured to filter the current slip rate of the rear left wheel according to the slip rate of the front left wheel at the previous time and the slip rate of the rear left wheel at the previous time, so as to obtain a real slip rate of the rear left wheel;

the fourth determining module 210 is configured to filter the current slip rate of the rear right wheel according to the slip rate of the front right wheel at the previous time and the slip rate of the rear right wheel at the previous time, so as to obtain the real slip rate of the rear right wheel.

In one embodiment, the first determining module 204 includes:

the first determining submodule is used for taking the maximum current wheel speed in the current wheel speeds of all the wheels as the current reference vehicle speed if the current wheel speed of all the wheels is larger than the reference vehicle speed at the previous moment; if the current wheel speed which is larger than the reference vehicle speed at the last moment does not exist in the current wheel speeds of all the wheels and the current moment is the initial braking moment, taking the minimum current wheel speed in the current wheel speeds of all the wheels as the initial reference vehicle speed, and determining the current reference vehicle speed according to the initial reference vehicle speed, the vehicle body deceleration and the first time difference between the current moment and the last moment;

the second determining submodule is used for acquiring wheels with the current wheel deceleration equal to a preset threshold value from all the wheels if the current wheel speeds of all the wheels do not have the current wheel speed larger than the reference vehicle speed at the previous moment and the current moment is not the initial braking moment, taking the current wheel speed of the wheels with the current wheel deceleration equal to the preset threshold value as the initial reference vehicle speed, and determining the current reference vehicle speed according to the initial reference vehicle speed, the vehicle body deceleration and the first time difference between the current moment and the previous moment;

and the third determining submodule is used for taking the reference vehicle speed at the previous moment as the initial reference vehicle speed and determining the current reference vehicle speed according to the initial reference vehicle speed, the vehicle body deceleration and the first time difference between the current moment and the previous moment if the current wheel speed of all wheels does not exist, the current moment is not the initial braking moment, and the wheels with the current wheel deceleration equal to the preset threshold value are not obtained from all the wheels.

In one embodiment, the first determination submodule, the second determination submodule, and the third determination submodule include:

the acquiring unit is used for acquiring a first product between the vehicle body deceleration and the first time difference, acquiring a first difference value between the initial reference vehicle speed and the first product, and taking the first difference value as the current reference vehicle speed.

and the judging unit is used for judging whether the braking process corresponding to the current moment belongs to first braking, if so, the deceleration value of the vehicle body is 0.6g, if not, the wheel speeds corresponding to the preset moments of all the wheels in the last braking process are obtained, and the deceleration of the vehicle body is determined according to the filter coefficient, the deceleration of the vehicle body of the last braking process, the maximum wheel speed in the wheel speeds corresponding to the preset moments of all the wheels in the last braking process and the second time difference between the preset moment and the preset moment.

In one embodiment, the determining unit includes:

the calculation subunit is used for calculating a second difference value between 1 and the filter coefficient and acquiring a second product between the second difference value and the vehicle body deceleration in the last braking process;

the first obtaining subunit is configured to obtain a third difference between a maximum wheel speed of wheel speeds of all wheels at a preset time in the last braking process and a maximum wheel speed of wheel speeds of all wheels at a preset time in the last braking process; acquiring a first ratio between the third difference and the second time difference; obtaining a third product between the first ratio and the filter coefficient;

and a second obtaining subunit operable to obtain a sum value between the second product and the third product, the sum value being used as the vehicle body deceleration.

In one embodiment, the third determining module 208 includes:

the first obtaining submodule is used for obtaining an absolute value of a fourth difference value between the slip ratio of the front left wheel at the previous moment and the slip ratio of the rear left wheel at the previous moment;

the second obtaining submodule is used for obtaining a fifth difference value between the current slip ratio of the rear left wheel and the absolute value of the fourth difference value;

and the third obtaining submodule is used for taking the fifth difference value as the real slip ratio of the rear left wheel.

The modules in the slip ratio calculation device can be wholly or partially realized by software, hardware and a combination thereof. The modules can be embedded in a hardware form or independent from a processor in the computer device, and can also be stored in a memory in the computer device in a software form, so that the processor can call and execute operations corresponding to the modules.

In one embodiment, a computer device is provided, which may be a server, the internal structure of which may be as shown in fig. 3. The computer device includes a processor, a memory, and a network interface connected by a system bus. Wherein the processor of the computer device is configured to provide computing and control capabilities. The memory of the computer device comprises a nonvolatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of an operating system and computer programs in the non-volatile storage medium. The database of the computer device is used for storing the current wheel speeds of all the wheels at the current moment, the current reference vehicle speed of the vehicle at the current moment, the current slip rate of each wheel at the current moment, the real slip rate of the rear left wheel and the real slip rate data of the rear right wheel. The network interface of the computer device is used for communicating with an external terminal through a network connection. The computer program is executed by a processor to implement a slip ratio calculation method.

Those skilled in the art will appreciate that the architecture shown in fig. 3 is merely a block diagram of some of the structures associated with the disclosed aspects and is not intended to limit the computing devices to which the disclosed aspects apply, as particular computing devices may include more or less components than those shown, or may combine certain components, or have a different arrangement of components.

In one embodiment, a computer device is provided, comprising a memory and a processor, the memory having a computer program stored therein, the processor implementing the following steps when executing the computer program:

acquiring current wheel speeds of all wheels of a vehicle at the current moment; all wheels comprise a front left wheel, a front right wheel, a rear left wheel and a rear right wheel; determining the current reference speed of the vehicle at the current moment according to the current wheel speeds of all wheels; determining the current slip rate of each wheel at the current moment according to the current wheel speed of each wheel and the current reference vehicle speed; filtering the current slip rate of the rear left wheel according to the slip rate of the front left wheel at the previous moment and the slip rate of the rear left wheel at the previous moment to obtain the real slip rate of the rear left wheel; and filtering the current slip rate of the rear right wheel according to the slip rate of the front right wheel at the previous moment and the slip rate of the rear right wheel at the previous moment to obtain the real slip rate of the rear right wheel.

In one embodiment, the processor, when executing the computer program, further performs the steps of:

In one embodiment, the processor when executing the computer program further performs the steps of:

and taking the fifth difference as the real slip ratio of the rear left wheel.

In one embodiment, a computer-readable storage medium is provided, having a computer program stored thereon, which when executed by a processor, performs the steps of:

acquiring current wheel speeds of all wheels of the vehicle at the current moment; all wheels comprise a front left wheel, a front right wheel, a rear left wheel and a rear right wheel; determining the current reference speed of the vehicle at the current moment according to the current wheel speeds of all wheels; determining the current slip rate of each wheel at the current moment according to the current wheel speed of each wheel and the current reference vehicle speed; filtering the current slip rate of the rear left wheel according to the slip rate of the front left wheel at the previous moment and the slip rate of the rear left wheel at the previous moment to obtain the real slip rate of the rear left wheel; and filtering the current slip rate of the rear right wheel according to the slip rate of the front right wheel at the previous moment and the slip rate of the rear right wheel at the previous moment to obtain the real slip rate of the rear right wheel.

In one embodiment, the computer program when executed by the processor further performs the steps of:

if the current wheel speed which is larger than the reference vehicle speed at the last moment exists in the current wheel speeds of all the wheels, taking the maximum current wheel speed in the current wheel speeds of all the wheels as the current reference vehicle speed; if the current wheel speed which is larger than the reference wheel speed at the last moment does not exist in the current wheel speeds of all the wheels and the current moment is the initial braking moment, taking the minimum current wheel speed in the current wheel speeds of all the wheels as the initial reference wheel speed, and determining the current reference wheel speed according to the initial reference wheel speed, the vehicle body deceleration and the first time difference between the current moment and the last moment;

calculating a second difference value between 1 and the filter coefficient, and acquiring a second product between the second difference value and the vehicle body deceleration in the last braking process; acquiring a third difference value between the maximum wheel speed of the wheel speeds of all the wheels corresponding to the preset time in the last braking process and the maximum wheel speed of the wheel speeds of all the wheels corresponding to the last time in the last braking process; acquiring a first ratio between the third difference and the second time difference; obtaining a third product between the first ratio and the filter coefficient; and acquiring a sum value between the second product and the third product, and taking the sum value as the vehicle body deceleration.

and taking the fifth difference as the real slip ratio of the rear left wheel.

In one embodiment, a computer program product is provided, comprising a computer program which, when executed by a processor, performs the steps of:

and taking the fifth difference as the real slip ratio of the rear left wheel.

It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by hardware instructions of a computer program, which can be stored in a non-volatile computer-readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. Any reference to memory, storage, database or other medium used in the embodiments provided herein can include at least one of non-volatile and volatile memory. Non-volatile Memory may include Read-Only Memory (ROM), magnetic tape, floppy disk, flash Memory, optical storage, or the like. Volatile Memory can include Random Access Memory (RAM) or external cache Memory. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM), for example.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A slip ratio calculation method, characterized in that the method comprises:

2. The method of claim 1, wherein determining a current reference speed of the vehicle at a current time based on current wheel speeds of all wheels comprises:

if the current wheel speed which is larger than the reference vehicle speed at the previous moment exists in the current wheel speeds of all the wheels, taking the maximum current wheel speed in the current wheel speeds of all the wheels as the current reference vehicle speed; if the current wheel speed which is larger than the reference vehicle speed at the previous moment does not exist in the current wheel speeds of all the wheels and the current moment is the initial braking moment, taking the minimum current wheel speed in the current wheel speeds of all the wheels as the initial reference vehicle speed, and determining the current reference vehicle speed according to the initial reference vehicle speed, the vehicle body deceleration and the first time difference between the current moment and the previous moment;

if the current wheel speed which is larger than the reference vehicle speed at the previous moment does not exist in the current wheel speeds of all the wheels and the current moment is not the initial braking moment, obtaining the wheels with the current wheel deceleration equal to the preset threshold value from all the wheels, taking the current wheel speed of the wheels with the current wheel deceleration equal to the preset threshold value as the initial reference vehicle speed, and determining the current reference vehicle speed according to the initial reference vehicle speed, the vehicle body deceleration and the first time difference between the current moment and the previous moment;

if the current wheel speed which is larger than the reference vehicle speed at the previous moment does not exist in the current wheel speeds of all the wheels, the current moment is not the initial braking moment, and the wheels with the current wheel deceleration equal to the preset threshold value are not obtained in all the wheels, taking the reference vehicle speed at the previous moment as the initial reference vehicle speed, and determining the current reference vehicle speed according to the initial reference vehicle speed, the vehicle body deceleration and the first time difference between the current moment and the previous moment.

3. The method of claim 2, wherein determining the current reference vehicle speed from the initial reference vehicle speed, a vehicle body deceleration, and a first time difference between a current time and a previous time comprises:

4. The method of claim 2, wherein the determining of the deceleration of the vehicle body comprises:

and judging whether the braking process corresponding to the current moment belongs to first braking, if so, obtaining the deceleration value of the vehicle body to be 0.6g, if not, obtaining the wheel speed corresponding to the preset moment of all the wheels in the last braking process, and determining the deceleration of the vehicle body according to a filter coefficient, the maximum wheel speed in the wheel speeds corresponding to the preset moment of all the wheels in the last braking process, and a second time difference between the preset moment and the last moment of the preset moment.

5. The method of claim 4, wherein determining the vehicle body deceleration based on the filter coefficient, the vehicle body deceleration of the last braking process, the maximum wheel speed among the wheel speeds of all the wheels at the preset time in the last braking process, and the second time difference between the preset time and the last time of the preset time comprises:

calculating a second difference value between 1 and the filter coefficient, and acquiring a second product between the second difference value and the vehicle body deceleration of the last braking process;

acquiring a third difference value between the maximum wheel speed of the wheel speeds of all the wheels corresponding to the preset time in the last braking process and the maximum wheel speed of the wheel speeds of all the wheels corresponding to the last time in the last braking process; acquiring a first ratio between the third difference and the second time difference; obtaining a third product between the first ratio and the filter coefficient;

6. The method according to claim 1, wherein the filtering the current slip ratio of the rear left wheel according to the slip ratio of the front left wheel at the previous moment and the slip ratio of the rear left wheel at the previous moment to obtain the real slip ratio of the rear left wheel comprises:

acquiring an absolute value of a fourth difference between the slip ratio of the front left wheel at the previous moment and the slip ratio of the rear left wheel at the previous moment;

7. A slip ratio calculation apparatus, characterized in that the apparatus comprises:

the first determination module is used for determining the current reference speed of the vehicle at the current moment according to the current wheel speeds of all wheels;

8. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor, when executing the computer program, implements the steps of the method of any of claims 1 to 6.

9. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps of the method of any one of claims 1 to 6.

10. A computer program product comprising a computer program, characterized in that the computer program realizes the steps of the method of any one of claims 1 to 6 when executed by a processor.