Vehicle cornering braking force distribution method and device, electronic device, and storage medium

Abstract

This application provides a method and device for distributing braking force during vehicle cornering, an electronic device, and a storage medium, applicable to the field of vehicle brake-by-wire technology. This application acquires real-time vehicle status information upon detecting cornering braking demand information, and then performs initial braking force distribution based on the longitudinal lateral acceleration and first brake pedal displacement from the real-time status information. Next, it inputs the first longitudinal vehicle speed and first steering wheel angle from the real-time status information into a linear two-degree-of-freedom vehicle model to obtain the vehicle's second yaw rate and second center-of-gravity deviation angle. Then, it calculates the vehicle's additional yaw moment based on the first yaw rate, first center-of-gravity deviation angle, second yaw rate, and second center-of-gravity deviation angle, and finally performs secondary braking force distribution based on the additional yaw moment. This application can effectively improve the stability and safety of vehicles during driving.

Description

Technical Field

[0001] This application relates to the field of vehicle brake-by-wire technology, and in particular to a method and device for distributing braking force during vehicle turning, electronic equipment, and storage medium. Background Technology

[0002] In related technologies, braking force distribution methods for brake-by-wire vehicles during cornering braking are mainly divided into two categories: one is a distribution method based on vertical load, which distributes braking force according to the proportion of vertical load on each wheel; the other is a distribution method based on multi-objective optimization, which distributes braking force to the four wheels by setting an optimization objective function and constraints. The first type of distribution method first allocates the initial braking force based on the proportion of vertical load on each wheel, and then adds the braking force required to generate additional yaw moment. In this case, it may cause one side of the wheels to lock up due to over-braking. The second type of distribution method may not be able to simultaneously meet the requirements of braking force and yaw moment, resulting in a situation where there is no solution in solving the optimization objective function. Therefore, it can be seen that the stability and safety of vehicles controlled by both distribution methods are relatively low during driving.

[0003] In summary, the technical problems existing in the relevant technologies need to be improved. Summary of the Invention

[0004] The main objective of this application is to provide a method and device for distributing braking force during vehicle turning, an electronic device, and a storage medium, which can effectively improve the stability and safety of the vehicle during driving.

[0005] To achieve the above objectives, one aspect of this application proposes a method for distributing braking force during vehicle turning, the method comprising the following steps:

[0006] When a turning braking demand is detected, the vehicle's real-time status information is obtained, including the first yaw rate, the first center of gravity offset angle, the first longitudinal vehicle speed, the first steering wheel angle, the first brake pedal displacement, and the longitudinal lateral acceleration.

[0007] The initial braking force is distributed to the vehicle based on the longitudinal lateral acceleration and the displacement of the first brake pedal;

[0008] Input the first longitudinal vehicle speed and the first steering wheel angle into a linear two-degree-of-freedom vehicle model to obtain the vehicle's second yaw rate and second center-of-gravity lateral angle.

[0009] The additional yaw moment of the vehicle is calculated based on the first yaw rate, the first center of gravity slant angle, the second yaw rate, and the second center of gravity slant angle.

[0010] The vehicle is then subjected to secondary braking force distribution based on the additional yaw moment.

[0011] In some embodiments, the initial braking force distribution to the vehicle based on the longitudinal lateral acceleration and the first brake pedal displacement includes:

[0012] Calculate the vertical load on each wheel based on the longitudinal lateral acceleration;

[0013] Calculate the proportion of the vertical load on each wheel;

[0014] Calculate the desired braking deceleration based on the displacement of the first brake pedal.

[0015] Calculate the desired braking force based on the desired braking deceleration;

[0016] The vehicle is initially braked based on the proportion of vertical load on each wheel and the desired braking force.

[0017] In some embodiments, the formula for calculating the vertical load of each wheel is as follows:

[0018]

[0019] Where a represents the front wheelbase, b represents the rear wheelbase, h represents the center of gravity height, and B f Indicates the front wheel track, B r Indicates the rear wheel track, a x a represents longitudinal acceleration. y F represents lateral acceleration. z_fl F represents the vertical load on the left front wheel. z_fr F represents the vertical load on the right front wheel. z_rl F represents the vertical load on the left rear wheel. z_rr The value represents the vertical load on the right rear wheel, m represents the total mass of the vehicle, and g represents the acceleration due to gravity.

[0020] In some embodiments, the formula for calculating the desired braking force is as follows:

[0021] F d =m·a d ;

[0022] Among them, a d F represents the desired braking deceleration. d For the expected braking force;

[0023] The initial braking force calculation formula for each wheel is as follows:

[0024]

[0025] Among them, F′ x_flThe initial distribution of braking force to the left front wheel; F′ x_fr The initial distribution of braking force to the right front wheel; F′ x_rl The initial braking force assigned to the left rear wheel; F′ x_rr The initial braking force is allocated to the left rear wheel.

[0026] In some embodiments, the step of inputting the first longitudinal vehicle speed and the first steering wheel angle into a linear two-degree-of-freedom vehicle model to obtain the vehicle's second yaw rate and second center-of-gravity lateral angle includes:

[0027] The second yaw rate is calculated using the following formula:

[0028]

[0029] The second centroid deflection angle is calculated using the following formula:

[0030]

[0031] Where, ω d β represents the second yaw rate. d The second centroid deviation angle is represented by μ, the road adhesion coefficient is represented by δ, the front wheel steering angle is represented by v, and the vehicle's longitudinal velocity is represented by k. f Indicates the front axle lateral stiffness, k r Indicates the rear axle lateral stiffness. The stability factor is represented by L = a + b, which represents the wheelbase of the car, and g represents the acceleration due to gravity.

[0032] In some embodiments, the secondary braking force distribution to the vehicle based on the additional yaw moment includes:

[0033] Based on the aforementioned additional yaw moment, the secondary distribution of braking force among the wheels of the vehicle is calculated using the following formula:

[0034]

[0035] Where ΔM represents the additional yaw moment, δ represents the front wheel steering angle, and ΔF x_fl ΔF x_fr ΔF x_rl ΔF x_rr These represent the secondary distribution values ​​of braking force for each wheel; B represents the wheel track of the vehicle.

[0036] In some embodiments, when performing secondary braking force distribution on the vehicle based on the additional yaw moment, the method satisfies the following constraints:

[0037] When the additional yaw moment is positive, the longitudinal force of the left wheel satisfies the following first preset requirement:

[0038] 0≤ΔF x_il ≤μ il ·F z_il -F′ x_il ;

[0039] Where i = f, r; F′ x_il ΔF represents the initial braking force distribution to the left wheel. x_il The secondary braking force distribution value for the left wheel, μ il This indicates the road adhesion coefficient of the front and rear wheels on the left side;

[0040] When the additional yaw moment is positive, the longitudinal force of the right wheel satisfies the following second preset requirement:

[0041] 0≤ΔF x_ir ≤F′ x_ir ;

[0042] Where i = f, r; F′ x_ir ΔF represents the initial braking force distribution to the right wheel. x_ir The secondary braking force distribution value for the right wheel;

[0043] When the additional yaw moment is negative, the longitudinal force of the left wheel satisfies the following third preset requirement:

[0044] 0≤ΔF x-il ≤F′ x-il ;

[0045] Where i = f, r; F′ x-il ΔF represents the initial braking force distribution to the left wheel. x_il The secondary braking force distribution value for the left wheel;

[0046] When the additional yaw moment is negative, the longitudinal force of the right wheel satisfies the following fourth preset requirement:

[0047] 0≤ΔF x_ir ≤μ ir ·F z_ir -F′ x_ir ;

[0048] Where i = f, r; F′ x_ir ΔF represents the initial braking force distribution value for the right wheel. x_ir μ is the secondary braking force distribution value for the right wheel. ir This indicates the road adhesion coefficient of the front and rear right wheels.

[0049] To achieve the above objectives, another aspect of this application provides a vehicle turning braking force distribution device, the device comprising:

[0050] The first module is used to obtain real-time vehicle status information when cornering braking demand information is detected. The real-time status information includes a first yaw rate, a first center of gravity offset angle, a first longitudinal vehicle speed, a first steering wheel angle, a first brake pedal displacement, and longitudinal lateral acceleration.

[0051] The second module is used to distribute the initial braking force to the vehicle based on the longitudinal lateral acceleration and the displacement of the first brake pedal.

[0052] The third module is used to input the first longitudinal vehicle speed and the first steering wheel angle into a linear two-degree-of-freedom vehicle model to obtain the vehicle's second yaw rate and second center of gravity deviation angle.

[0053] The fourth module is used to calculate the vehicle's additional yaw moment based on the first yaw rate, the first center of gravity eccentricity angle, the second yaw rate, and the second center of gravity eccentricity angle.

[0054] The fifth module is used to distribute the secondary braking force to the vehicle based on the additional yaw moment.

[0055] To achieve the above objectives, another aspect of this application provides an electronic device, comprising:

[0056] At least one processor;

[0057] At least one memory for storing at least one program;

[0058] When the at least one program is executed by the at least one processor, the at least one processor performs the method described above.

[0059] To achieve the above objectives, another aspect of the embodiments of this application proposes a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method.

[0060] The embodiments of this application include at least the following beneficial effects: This application provides a method and device for distributing braking force during vehicle turning, an electronic device, and a storage medium. This solution obtains the real-time state information of the vehicle when turning braking demand information is detected, and then performs initial braking force distribution on the vehicle based on the longitudinal lateral acceleration and the first brake pedal displacement in the real-time state information. Next, the first longitudinal vehicle speed and the first steering wheel angle in the real-time state information are input into a linear two-degree-of-freedom vehicle model to obtain the second yaw rate and the second centroid offset angle of the vehicle. Then, the additional yaw moment of the vehicle is calculated based on the first yaw rate, the first centroid offset angle, the second yaw rate, and the second centroid offset angle. Finally, the vehicle performs secondary braking force distribution based on the additional yaw moment. This embodiment achieves secondary distribution of braking force by considering the influence of yaw rate and centroid offset angle under turning braking conditions, thereby effectively preventing the situation where the optimization objective is unsolvable under high-intensity braking, so that the braking system can continuously have reliable braking force, thereby effectively improving the stability and safety of the vehicle during driving. Attached Figure Description

[0061] Figure 1 This is a flowchart of the vehicle turning braking force distribution method provided in the embodiments of this application;

[0062] Figure 2 This is a schematic diagram of the tire attachment ellipse model provided in the embodiments of this application;

[0063] Figure 3 This is a complete implementation flowchart of the vehicle turning braking force distribution method provided in the embodiments of this application;

[0064] Figure 4 This is a schematic diagram comparing yaw rates provided in an embodiment of this application;

[0065] Figure 5 This is a schematic diagram comparing the centroid offset angles provided in the embodiments of this application;

[0066] Figure 6 This is a schematic diagram of the vehicle turning braking force distribution device provided in the embodiments of this application;

[0067] Figure 7 This is a schematic diagram of the hardware structure of the electronic device provided in the embodiments of this application. Detailed Implementation

[0068] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit it. In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with those of this application; they are merely examples of apparatuses and methods consistent with some aspects of the embodiments of this application.

[0069] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0070] The vehicle turning braking force distribution method provided in this application relates to the field of vehicle brake-by-wire technology. This method can be applied to a terminal, a server, or software running on either a terminal or a server. In some embodiments, the terminal can be a smartphone, tablet, laptop, desktop computer, smart speaker, smartwatch, or in-vehicle terminal, but is not limited to these. The server can be configured as an independent physical server, a server cluster or distributed system composed of multiple physical servers, or a cloud server providing basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, CDN, and big data and artificial intelligence platforms. The server can also be a node server in a blockchain network. The software can be an application implementing the vehicle turning braking force distribution method, but is not limited to the above forms.

[0071] This application can be used in a wide variety of general-purpose or special-purpose computer system environments or configurations. Examples include: personal computers, server computers, handheld or portable devices, tablet devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable consumer electronics, network PCs, minicomputers, mainframe computers, and distributed computing environments including any of the above systems or devices. This application can be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform specific tasks or implement specific abstract data types. This application can also be practiced in distributed computing environments where tasks are performed by remote processing devices connected via a communication network. In distributed computing environments, program modules can reside in local and remote computer storage media, including storage devices.

[0072] Figure 1 This is an optional flowchart of the vehicle turning braking force distribution method provided in the embodiments of this application. Figure 1 The method may include, but is not limited to, steps S110 to S150:

[0073] Step S110: When the turning braking demand information is detected, the real-time status information of the vehicle is obtained, including the first yaw rate, the first center of gravity offset angle, the first longitudinal vehicle speed, the first steering wheel angle, the first brake pedal displacement, and the longitudinal lateral acceleration.

[0074] Step S120: Distribute initial braking force to the vehicle based on longitudinal lateral acceleration and first brake pedal displacement;

[0075] Step S130: Input the first longitudinal vehicle speed and the first steering wheel angle into the linear two-degree-of-freedom car model to obtain the second yaw rate and the second center of gravity deviation angle of the vehicle.

[0076] Step S140: Calculate the additional yaw moment of the vehicle based on the first yaw rate, the first center of gravity offset angle, the second yaw rate, and the second center of gravity offset angle;

[0077] Step S150: Distribute the secondary braking force to the vehicle based on the additional yaw moment.

[0078] In this embodiment, after the vehicle needs to turn and brake and real-time information of the vehicle is obtained, the vertical load of each wheel is calculated based on the longitudinal lateral acceleration, and the proportion of the vertical load of each wheel is calculated; at the same time, the desired braking deceleration is calculated based on the displacement of the first brake pedal, and the desired braking force is calculated based on the desired braking deceleration; then, the initial braking force is distributed to the vehicle based on the proportion of the vertical load of each wheel and the desired braking force.

[0079] Understandably, the formula for calculating the vertical load on each wheel is as follows:

[0080]

[0081] Where a represents the front wheelbase, b represents the rear wheelbase, h represents the center of gravity height, and B f Indicates the front wheel track, B r Indicates the rear wheel track, a x a represents longitudinal acceleration. y F represents lateral acceleration. z_fl F represents the vertical load on the left front wheel. z_fr F represents the vertical load on the right front wheel. z_rl F represents the vertical load on the left rear wheel. z_rrThe value represents the vertical load on the right rear wheel, m represents the total mass of the vehicle, and g represents the acceleration due to gravity.

[0082] The formula for calculating the desired braking force is as follows:

[0083] F d =m·a d ;

[0084] Among them, a d F represents the desired braking deceleration. d For the expected braking force;

[0085] The initial braking force calculation formula for each wheel is as follows:

[0086]

[0087] Among them, F′ x_fl The initial distribution of braking force to the left front wheel; F′ x_fr The initial distribution of braking force to the right front wheel; F′ x_rl The initial braking force assigned to the left rear wheel; F′ x_rr The initial braking force is allocated to the left rear wheel.

[0088] In this embodiment, after the initial distribution of vehicle braking force is completed according to the above method, the obtained first longitudinal vehicle speed and first steering wheel angle are input into a linear two-degree-of-freedom vehicle model to obtain the vehicle's second yaw rate and second center-of-gravity deviation angle. It can be understood that the second yaw rate is calculated using the following formula:

[0089]

[0090] The second centroid deflection angle is calculated using the following formula:

[0091]

[0092] Where, ω d β represents the second yaw rate. d The second center of gravity deflection angle is represented by μ, the road adhesion coefficient is represented by δ, the front wheel steering angle is represented by ν, and the vehicle's longitudinal velocity is represented by k. f Indicates the front axle lateral stiffness, k r Indicates the rear axle lateral stiffness. The stability factor is represented by L = a + b, which represents the wheelbase of the car, and g represents the acceleration due to gravity.

[0093] After calculating the second yaw rate (ideal yaw rate) and the second center-of-gravity sideslip angle (ideal sideslip angle) of the current vehicle, the second yaw rate is compared with the first yaw rate, and the second sideslip angle is compared with the first sideslip angle. The differences obtained from the comparison are input into the yaw rate control module and the sideslip angle control module, respectively, to adjust the vehicle's dynamic performance. Since there is a coupling relationship between the actual yaw rate and the sideslip angle of the vehicle, the differences between the first and second yaw rates, and the differences between the first and second sideslip angles, are substituted into the two-degree-of-freedom vehicle model formula to calculate the corresponding results. Then, the corresponding results are weighted and summed to obtain the additional yaw moment.

[0094] In this embodiment of the application, after calculating the additional yaw moment, the secondary distribution of braking force to each wheel in the vehicle is calculated using the following formula:

[0095]

[0096] Where ΔM represents the additional yaw moment, δ represents the front wheel steering angle, and ΔF x_fl ΔF x_fr ΔF x_rl ΔF x_rr These represent the secondary distribution values ​​of braking force for each wheel; B represents the wheel track of the vehicle.

[0097] Specifically, considering the limitations of ground adhesion conditions, the longitudinal and lateral forces provided by the tires should meet the following requirements. Figure 2 The tire adhesion ellipse shown indicates that increasing the longitudinal force leads to a decrease in the lateral force. This embodiment uses the following formula to rationally distribute the braking force (i.e., longitudinal force) so that the final longitudinal force distributed to each tire does not exceed the limit value:

[0098]

[0099] Among them, F x_ij For the longitudinal force of the tire; F y_ij The lateral force of the tire is i = f, r; j = l, r.

[0100] This embodiment adjusts the braking torque of the four wheels a second time to meet the required additional yaw moment. Specifically, increasing the braking force on the left wheel and decreasing the braking force on the right wheel generates a positive additional yaw moment; conversely, decreasing the braking force on the left wheel and increasing the braking force on the right wheel generates a negative additional yaw moment. Under low to medium braking intensity, the wheel on the side with increased braking force does not reach its tire adhesion limit; however, under high braking intensity, the wheel on that side may exceed its adhesion limit, leading to wheel lock-up. Due to the tire adhesion limit, this embodiment applies upper and lower limits to the secondary distribution of braking force to prevent wheel lock-up on one side during high-braking-intensity cornering, thereby ensuring vehicle handling stability and safety. Furthermore, for the wheel on the side about to reach the lock-up threshold, the required additional yaw moment will be achieved by adjusting the braking force of the other wheel, ensuring vehicle safety under various complex road conditions.

[0101] It is understood that when this embodiment performs secondary braking force distribution on the vehicle based on the additional yaw moment, the following constraints must be met:

[0102] When the additional yaw moment is positive, the longitudinal force of the left wheel satisfies the following first preset requirement:

[0103] 0≤ΔF x_il ≤μ il ·F z_il -F′ x_il ;

[0104] Where i = f, r; F′ x_il ΔF represents the initial braking force distribution to the left wheel. x_il The secondary braking force distribution value for the left wheel, μ il This indicates the road adhesion coefficient of the front and rear wheels on the left side;

[0105] When the additional yaw moment is positive, the longitudinal force of the right wheel satisfies the following second preset requirement:

[0106] 0≤ΔF x_ir ≤F′ x_ir ;

[0107] Where i = f, r; F′ x-ir ΔF represents the initial braking force distribution to the right wheel. x_ir The secondary braking force distribution value for the right wheel;

[0108] When the additional yaw moment is negative, the longitudinal force of the left wheel satisfies the following third preset requirement:

[0109] 0≤ΔF x_il ≤F′ x_il ;

[0110] Where i = f, r; F′ x_il ΔF represents the initial braking force distribution to the left wheel. x_il The secondary braking force distribution value for the left wheel;

[0111] When the additional yaw moment is negative, the longitudinal force of the right wheel satisfies the following fourth preset requirement:

[0112] 0≤ΔF x_ir ≤μ ir ·F z_ir -F′ x_ir ;

[0113] Where i = f, r; F′ x_ir ΔF represents the initial braking force distribution value for the right wheel. x_ir μ is the secondary braking force distribution value for the right wheel. ir This indicates the road adhesion coefficient of the front and rear right wheels.

[0114] To achieve good braking safety and improve vehicle stability, this embodiment defines equal longitudinal forces distributed to the left and right wheels as the optimization objective. The goal is to maintain the total braking force of the vehicle to the maximum extent possible while ensuring the additional yaw moment is met. Therefore, the optimization objective function is defined as follows:

[0115] Min:J=(F x_fl +F x_rl -F xfr -F x_rr ) 2 ;

[0116] Considering the time-sensitive nature of vehicle control, this embodiment selects Sequential Quadratic Programming (SQP), which offers good real-time performance and high allocation accuracy, for the secondary allocation calculation of braking force. This allows the vehicle to adjust the braking force of the four wheels under different braking conditions to meet the additional yaw moment. Since this embodiment already satisfies the requirements for braking intensity and tire utilization based on the vertical load of each wheel during the initial allocation, it is only necessary to set the equality of the longitudinal forces of the secondary allocation on the left and right wheels as the objective function of the Sequential Quadratic Programming method, and establish the equality constraints of the additional yaw moment and the upper and lower limits of the control variables.

[0117] It is understood that the mathematical description of the sequential quadratic programming provided in this embodiment is as follows:

[0118]

[0119] stAx≤B;

[0120] A eq x = B eq ;

[0121] lb≤x≤ub;

[0122] Where: control variable x = [ΔF] x_fl ΔF x_fr ΔF x_rl ΔF x_rr H is the second derivative matrix of the objective function; f is the vector of the first term in the quadratic programming; A and B are the coefficient matrix and right-hand vector of the linear inequality constraint, respectively; Aeq and Beq are the coefficient matrix and right-hand vector of the linear equality constraint, respectively; lb and ub are the upper and lower limits of the independent variable, respectively.

[0123] After the target-optimized secondary distribution of braking force is completed in this embodiment, the final braking force calculation formula for each wheel is as follows:

[0124] When the additional yaw moment is positive:

[0125]

[0126] When the additional yaw moment is negative:

[0127]

[0128] Among them, F x_fl F represents the final braking force of the left front wheel. x_fr F represents the final braking force of the right front wheel. x_rl F represents the final braking force of the left rear wheel. x_rr This indicates the final braking force of the right rear wheel.

[0129] After completing the secondary distribution of braking force, the braking force distribution control to each wheel will be terminated when the braking demand is detected.

[0130] In some embodiments, such as Figure 3 As shown, the complete implementation process of the vehicle turning braking force distribution method provided in this application includes, but is not limited to, the following steps:

[0131] Step S310: After detecting the turning braking demand, obtain the real-time status information of the vehicle;

[0132] Step S320: Distribute the initial braking force according to the desired braking force and the vertical load ratio of each wheel;

[0133] Step S330: Compare the ideal yaw rate and ideal centroid lateral angle calculated by the linear two-degree-of-freedom model with the actual yaw rate and actual centroid lateral angle in the real-time state information to obtain the required additional yaw torque.

[0134] Step S340: Determine whether the additional yaw moment is greater than or equal to 0. If yes, proceed to step S350; otherwise, proceed to step S360.

[0135] Step S350: Add the secondary distribution braking force value to the initial braking force value of each wheel on the left; subtract the secondary distribution braking force value from the initial braking force value of each wheel on the right.

[0136] Step S360: Subtract the secondary distribution braking force value from the initial braking force value of each wheel on the left; add the secondary distribution braking force value to the initial braking force value of each wheel on the right.

[0137] Step S370: Determine whether the braking demand needs to be released. If not, proceed to step S320; otherwise, end the braking force distribution process.

[0138] In some embodiments, application tests of the vehicle turning braking force distribution method provided in this application can yield results. Figure 4 and Figure 5 The diagram shown illustrates the effect. Specifically, with an initial speed of 90 km / h, a steering wheel angle of 45° in the first second, and emergency braking in the third second, from... Figure 4 and Figure 5 It is known that the target yaw angle change range obtained by the method of this application is close to the actual yaw angle change range, and the target centroid deviation angle obtained by the method of this application has a smaller fluctuation compared to the actual centroid deviation angle. Therefore, when the vehicle is subjected to turn braking control by the method of this application, the stability and safety of the vehicle during driving can be effectively improved.

[0139] Therefore, this embodiment of the application performs an initial distribution of braking force based on the vertical load of each wheel, and uses an optimization algorithm to solve the objective function to achieve a secondary distribution of braking force. During execution, the relationship between different braking intensities and tire adhesion limits is considered, which can effectively avoid the possibility of one-sided wheel lock-up after secondary braking force distribution under high braking intensity, ensuring driving safety and stability. Furthermore, this embodiment achieves accurate tracking of the vehicle's yaw rate and sideslip angle under cornering braking conditions, especially under high-intensity braking conditions, effectively preventing situations where the optimization objective is unsolvable, ensuring the braking system continuously possesses reliable braking force, and effectively improving overall braking performance and vehicle handling stability.

[0140] Reference Figure 6 This application provides a vehicle turning braking force distribution device, the device comprising:

[0141] The first module 610 is used to obtain real-time status information of the vehicle when a turning braking demand information is detected. The real-time status information includes a first yaw rate, a first center of gravity offset angle, a first longitudinal vehicle speed, a first steering wheel angle, a first brake pedal displacement, and longitudinal lateral acceleration.

[0142] The second module 620 is used to initially distribute braking force to the vehicle based on the longitudinal lateral acceleration and the displacement of the first brake pedal;

[0143] The third module 630 is used to input the first longitudinal vehicle speed and the first steering wheel angle into the linear two-degree-of-freedom car model to obtain the second yaw rate and the second center of gravity deviation angle of the vehicle.

[0144] The fourth module 640 is used to calculate the additional yaw moment of the vehicle based on the first yaw rate, the first center of gravity deviation angle, the second yaw rate, and the second center of gravity deviation angle.

[0145] The fifth module 650 is used to distribute the secondary braking force to the vehicle based on the additional yaw moment.

[0146] It is understood that the content of the above method embodiments is applicable to the present device embodiments. The specific functions implemented by the present device embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0147] This application also provides an electronic device, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the above-described vehicle turning braking force distribution method. This electronic device can be any smart terminal, including a tablet computer, an in-vehicle computer, or similar device.

[0148] It is understood that the content of the above method embodiments is applicable to this device embodiment. The specific functions implemented by this device embodiment are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0149] Please see Figure 7 , Figure 7 The hardware structure of an electronic device according to another embodiment is illustrated. The electronic device includes:

[0150] The processor 710 can be implemented using a general-purpose CPU (Central Processing Unit), microprocessor, application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this application.

[0151] The memory 720 can be implemented as a read-only memory (ROM), a static storage device, a dynamic storage device, or a random access memory (RAM). The memory 720 can store the operating system and other applications. When the technical solutions provided in the embodiments of this specification are implemented through software or firmware, the relevant program code is stored in the memory 720 and is called and executed by the processor 710 to execute the vehicle turning braking force distribution method of the embodiments of this application.

[0152] The input / output interface 730 is used to implement information input and output;

[0153] The communication interface 740 is used to enable communication and interaction between this device and other devices. Communication can be achieved through wired means (such as USB, network cable, etc.) or wireless means (such as mobile network, WIFI, Bluetooth, etc.).

[0154] Bus 750 transmits information between various components of the device (e.g., processor 710, memory 720, input / output interface 730, and communication interface 740);

[0155] The processor 710, memory 720, input / output interface 730 and communication interface 740 are connected to each other within the device via bus 750.

[0156] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described vehicle turning braking force distribution method.

[0157] It is understood that the content of the above method embodiments is applicable to this storage medium embodiment. The specific functions implemented in this storage medium embodiment are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those achieved in the above method embodiments.

[0158] Memory, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs and non-transitory computer-executable programs. Furthermore, memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, memory may optionally include memory remotely located relative to the processor, and these remote memories can be connected to the processor via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0159] The embodiments described in this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided by the embodiments of this application. As those skilled in the art will know, with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of this application are also applicable to similar technical problems.

[0160] Those skilled in the art will understand that the technical solutions shown in the figures do not constitute a limitation on the embodiments of this application, and may include more or fewer steps than shown, or combine certain steps, or different steps.

[0161] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to the first requirement.

[0162] Those skilled in the art will understand that all or some of the steps in the methods disclosed above, as well as the functional modules / units in the systems and devices, can be implemented as software, firmware, hardware, or suitable combinations thereof.

[0163] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0164] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0165] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of the units described above is only a logical functional division, and in the first implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0166] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to the first requirement.

[0167] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0168] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes multiple instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing programs, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0169] The preferred embodiments of the present application have been described above with reference to the accompanying drawings, but this does not limit the scope of the claims of the present application. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and substance of the embodiments of the present application shall be within the scope of the claims of the present application.

Claims

1. A method for distributing braking force when a vehicle is turning, characterized in that, The method includes the following steps: When a turning braking demand is detected, the vehicle's real-time status information is obtained, including the first yaw rate, the first center of gravity offset angle, the first longitudinal vehicle speed, the first steering wheel angle, the first brake pedal displacement, and the longitudinal lateral acceleration. The initial braking force is distributed to the vehicle based on the longitudinal lateral acceleration and the displacement of the first brake pedal; Input the first longitudinal vehicle speed and the first steering wheel angle into a linear two-degree-of-freedom vehicle model to obtain the vehicle's second yaw rate and second center-of-gravity lateral angle. The additional yaw moment of the vehicle is calculated based on the first yaw rate, the first center of gravity slant angle, the second yaw rate, and the second center of gravity slant angle. The vehicle is subjected to secondary braking force distribution based on the additional yaw moment, the secondary braking force distribution including: The secondary distribution of braking force to each wheel is calculated using the following formula: M; where, Indicates the additional yaw moment. Indicates the front wheel steering angle. These represent the secondary distribution values ​​of braking force for each wheel; B represents the vehicle's track width. The following constraints must be met: When the additional yaw moment is positive, the longitudinal force of the left wheel satisfies: Where i = f, r; The initial braking force distribution value for the left wheel; The secondary braking force distribution value for the left wheel. This indicates the road adhesion coefficient of the front and rear left wheels. Indicates the vertical load on the left wheel; When the additional yaw moment is positive, the longitudinal force of the right wheel satisfies: Where i = f, r; The initial braking force distribution value for the right wheel; The secondary braking force distribution value for the right wheel; When the additional yaw moment is negative, the longitudinal force of the left wheel satisfies: Where i = f, r; The initial braking force distribution value for the left wheel; The secondary braking force distribution value for the left wheel; When the additional yaw moment is negative, the longitudinal force of the right wheel satisfies: Where i = f, r; The initial braking force distribution value for the right wheel. This is the secondary braking force distribution value for the right wheel. The vertical load is for the right wheel. This indicates the road adhesion coefficient of the front and rear right wheels; Meanwhile, the secondary braking force distribution also satisfies the relationship between the longitudinal force and the lateral force of the tire based on the tire adhesion ellipse model. The optimization objective is to make the longitudinal force of the secondary distribution of the left and right wheels of the whole vehicle equal. The secondary braking force distribution is solved by the sequential quadratic programming method. During the secondary braking force distribution process, the initial braking force distribution - additional yaw moment calculation - secondary braking force distribution process is continuously executed in a loop until the braking release requirement is detected.

2. The method according to claim 1, characterized in that, The initial braking force distribution to the vehicle based on the longitudinal lateral acceleration and the first brake pedal displacement includes: Calculate the vertical load on each wheel based on the longitudinal lateral acceleration; Calculate the proportion of vertical load on each wheel; Calculate the desired braking deceleration based on the displacement of the first brake pedal; Calculate the desired braking force based on the desired braking deceleration; The vehicle is initially braked based on the proportion of vertical load on each wheel and the desired braking force.

3. The method according to claim 2, characterized in that, The formula for calculating the vertical load of each wheel is as follows: ； Where 'a' represents the front wheelbase and 'b' represents the rear wheelbase. Indicates the height of the center of mass. Indicates the front wheel track. Indicates the rear wheel track. Indicates longitudinal acceleration. Indicates lateral acceleration. This indicates the vertical load on the left front wheel. This indicates the vertical load on the right front wheel. This indicates the vertical load on the left rear wheel. The value represents the vertical load on the right rear wheel, m represents the total mass of the vehicle, and g represents the acceleration due to gravity.

4. The method according to claim 3, characterized in that, The formula for calculating the desired braking force is as follows: ； in, The desired braking deceleration; For the expected braking force; The initial braking force calculation formula for each wheel is as follows: ； in, The initial distribution of braking force to the left front wheel; The initial distribution of braking force to the right front wheel; The initial distribution of braking force to the left rear wheel; The initial braking force is allocated to the left rear wheel.

5. The method according to claim 4, characterized in that, The step of inputting the first longitudinal vehicle speed and the first steering wheel angle into a linear two-degree-of-freedom vehicle model to obtain the vehicle's second yaw rate and second center-of-gravity lateral angle includes: The second yaw rate is calculated using the following formula: ； The second centroid deflection angle is calculated using the following formula: ； in, This represents the second yaw rate. This indicates the second centroid deflection angle. Indicates the road surface adhesion coefficient. Indicates the front wheel steering angle. For the longitudinal speed of the car, Indicates the front axle lateral stiffness. K represents the rear axle lateral stiffness, and K represents the stability factor. L represents the wheelbase of the car, L = a + b, and g represents the acceleration due to gravity.

6. A vehicle turning braking force distribution device, characterized in that, The device includes: The first module is used to obtain real-time vehicle status information when cornering braking demand information is detected. The real-time status information includes a first yaw rate, a first center of gravity offset angle, a first longitudinal vehicle speed, a first steering wheel angle, a first brake pedal displacement, and longitudinal lateral acceleration. The second module is used to distribute the initial braking force to the vehicle based on the longitudinal lateral acceleration and the displacement of the first brake pedal. The third module is used to input the first longitudinal vehicle speed and the first steering wheel angle into a linear two-degree-of-freedom car model to obtain the vehicle's second yaw rate and second center of gravity deviation angle. The fourth module is used to calculate the vehicle's additional yaw moment based on the first yaw rate, the first center of gravity eccentricity angle, the second yaw rate, and the second center of gravity eccentricity angle. The fifth module is used to perform secondary braking force distribution on the vehicle based on the additional yaw moment. This secondary braking force distribution includes calculating the secondary distribution amount of braking force to each wheel using the following formula: M; where, Indicates the additional yaw moment. Indicates the front wheel steering angle. Let A and B represent the secondary distribution values ​​of braking force for each wheel; B represents the vehicle track width; the following constraints must be met: When the additional yaw moment is positive, the longitudinal force of the left wheel satisfies: Where i = f, r; The initial braking force distribution value for the left wheel; The secondary braking force distribution value for the left wheel. This indicates the road adhesion coefficient of the front and rear left wheels. Indicates the vertical load on the left wheel; When the additional yaw moment is positive, the longitudinal force of the right wheel satisfies: Where i = f, r; The initial braking force distribution value for the right wheel; The secondary braking force distribution value for the right wheel; When the additional yaw moment is negative, the longitudinal force of the left wheel satisfies: Where i = f, r; The initial braking force distribution value for the left wheel; The secondary braking force distribution value for the left wheel; When the additional yaw moment is negative, the longitudinal force of the right wheel satisfies: Where i = f, r; The initial braking force distribution value for the right wheel. This is the secondary braking force distribution value for the right wheel. The vertical load is for the right wheel. This indicates the road adhesion coefficient of the front and rear right wheels; Meanwhile, the secondary braking force distribution also satisfies the relationship between the longitudinal force and lateral force of the tire constrained by the tire adhesion ellipse model, with the optimization objective of equal longitudinal force distribution on the left and right wheels of the whole vehicle, and solves the secondary braking force distribution by sequential quadratic programming method; in the process of secondary braking force distribution, the process of initial braking force distribution - additional yaw moment calculation - secondary braking force distribution is continuously executed in a loop until the need to release braking is detected.

7. An electronic device, characterized in that, include: At least one processor; At least one memory for storing at least one program; When the at least one program is executed by the at least one processor, the at least one processor implements the method as described in any one of claims 1 to 5.

8. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the method of any one of claims 1 to 5.

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